//www.getgobooth.com/ 必威体育下载 daily 15 2024-08-20 10:33:36 apsoffice@iphy.ac.cn apsoffice@iphy.ac.cn 2024-08-20 10:33:36 zh Copyright ©Acta Physica Sinica All Rights Reserved. 京ICP备05002789号-1 Address: PostCode：100190 Phone: 010-82649829，82649241,82649863 Email: apsoffice@iphy.ac.cn Copyright ©Acta Physica Sinica All Rights Reserved apsoffice@iphy.ac.cn 1000-3290 //www.getgobooth.com/en/article/doi/10.7498/aps.50.189 Author(s): MU WEI-BING, CHEN PAN-XUN <br/><p>The dose would be enhanced on the low- Z material side when X-ray enters the interface constructed with two different materials.The mechanism of dose enhancement has been discussed and the Dose Enhancement Factors of W-Si,W-SiO2,Ta-Si and Ta-SiO2 interfaces are calculated by the Monte-Carlo method.</p> <br/>Acta Physica Sinica. 2001 50(2): 189-192. Published 2001-01-05 Author(s): MU WEI-BING, CHEN PAN-XUN <br/><p>The dose would be enhanced on the low- Z material side when X-ray enters the interface constructed with two different materials.The mechanism of dose enhancement has been discussed and the Dose Enhancement Factors of W-Si,W-SiO2,Ta-Si and Ta-SiO2 interfaces are calculated by the Monte-Carlo method.</p> <br/>Acta Physica Sinica. 2001 50(2): 189-192. Published 2001-01-05 MONTE-CARLO CALCULATION OF X-RAY DOSE ENHANCEMENT FACTOR NEARBY HIGH Z METAL CONNECTED INTERFACE MU WEI-BING, CHEN PAN-XUN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 189-192. article doi:10.7498/aps.50.189 10.7498/aps.50.189 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.189 189-192 //www.getgobooth.com/en/article/doi/10.7498/aps.50.193 Author(s): ZHANG HU-YONG, MA YU-GANG, SU QIAN-MIN, SHEN WEN-QING, CAI XIANG-ZHOU, FANG DE-QING, HU PENG-YUN, HAN DING-DING <br/><p>Within the framework of an isospin-dependent quantum molecular dynamics (IQMD) model,the emission features of light particles in 112Sn+112Sn and 124Sn+124Sn are investigated at different beam energy,different impact parameter,different EOS and different nucleon-nucleon cross section.Calculations show that the ratios of light particles are consistent with the systematics of entrance channel isospin and the midrapidity region can emit more neutron-rich particles than projectiles-like rapidity.In addition,it is found that the light particle ratio is sensitive to the nuclear EOS,but not to the nucleon-nucleon cross section,which makes it possible to extract the isospin-dependent EOS.</p> <br/>Acta Physica Sinica. 2001 50(2): 193-197. Published 2001-01-05 Author(s): ZHANG HU-YONG, MA YU-GANG, SU QIAN-MIN, SHEN WEN-QING, CAI XIANG-ZHOU, FANG DE-QING, HU PENG-YUN, HAN DING-DING <br/><p>Within the framework of an isospin-dependent quantum molecular dynamics (IQMD) model,the emission features of light particles in 112Sn+112Sn and 124Sn+124Sn are investigated at different beam energy,different impact parameter,different EOS and different nucleon-nucleon cross section.Calculations show that the ratios of light particles are consistent with the systematics of entrance channel isospin and the midrapidity region can emit more neutron-rich particles than projectiles-like rapidity.In addition,it is found that the light particle ratio is sensitive to the nuclear EOS,but not to the nucleon-nucleon cross section,which makes it possible to extract the isospin-dependent EOS.</p> <br/>Acta Physica Sinica. 2001 50(2): 193-197. Published 2001-01-05 ISOSPIN EFFECTS ON THE LIGHT PARTICLES IN INTERMEDIATE ENERGY HEAVY ION COLLISIONS ZHANG HU-YONG, MA YU-GANG, SU QIAN-MIN, SHEN WEN-QING, CAI XIANG-ZHOU, FANG DE-QING, HU PENG-YUN, HAN DING-DING 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 193-197. article doi:10.7498/aps.50.193 10.7498/aps.50.193 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.193 193-197 //www.getgobooth.com/en/article/doi/10.7498/aps.50.198 Author(s): HE MING, DUAN YI-WU, ZHU XI-WEN, SHI LEI <br/><p>We have solved the Shr?dinger equation of three Fermi ions with coplanar configuration in a Paul trap,when the whole spin angular momentum of the system is S=1/2 or 3/2.The structure and quantum dynamics of this system are investigated by inspecting the wave function nodal structure and the shape-density.At the same time,we compare our result with that of three Bose ions system and three ions system in classical condition.</p> <br/>Acta Physica Sinica. 2001 50(2): 198-203. Published 2001-01-05 Author(s): HE MING, DUAN YI-WU, ZHU XI-WEN, SHI LEI <br/><p>We have solved the Shr?dinger equation of three Fermi ions with coplanar configuration in a Paul trap,when the whole spin angular momentum of the system is S=1/2 or 3/2.The structure and quantum dynamics of this system are investigated by inspecting the wave function nodal structure and the shape-density.At the same time,we compare our result with that of three Bose ions system and three ions system in classical condition.</p> <br/>Acta Physica Sinica. 2001 50(2): 198-203. Published 2001-01-05 QUANTUM PROBLEM OF THREE FERMI IONS WITH COPLANAR CONFIGURATION IN A PAUL TRAP HE MING, DUAN YI-WU, ZHU XI-WEN, SHI LEI 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 198-203. article doi:10.7498/aps.50.198 10.7498/aps.50.198 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.198 198-203 //www.getgobooth.com/en/article/doi/10.7498/aps.50.204 Author(s): LI YU-TONG, ZHANG JIE, CHEN LI-MING, ZHAO LI-ZENG, XIA JIANG-FAN, TENG HAO, LI YING-JUN, ZHU CHENG-YIN, JIANG WEN-MIAN <br/><p>The local density fluctuation in femtosecond laser plasmas has been studied using optical shadowgraphy and scattering imaging techniques.The instability of filamentation in the laser plasma has been observed,and the local density fluctuation studied.The result shows that this instability of filamentation is caused by the ponderomotive force.</p> <br/>Acta Physica Sinica. 2001 50(2): 204-208. Published 2001-01-05 Author(s): LI YU-TONG, ZHANG JIE, CHEN LI-MING, ZHAO LI-ZENG, XIA JIANG-FAN, TENG HAO, LI YING-JUN, ZHU CHENG-YIN, JIANG WEN-MIAN <br/><p>The local density fluctuation in femtosecond laser plasmas has been studied using optical shadowgraphy and scattering imaging techniques.The instability of filamentation in the laser plasma has been observed,and the local density fluctuation studied.The result shows that this instability of filamentation is caused by the ponderomotive force.</p> <br/>Acta Physica Sinica. 2001 50(2): 204-208. Published 2001-01-05 STUDY ON FILAMENTATION IN FEMTOSECOND LASER PLASMAS LI YU-TONG, ZHANG JIE, CHEN LI-MING, ZHAO LI-ZENG, XIA JIANG-FAN, TENG HAO, LI YING-JUN, ZHU CHENG-YIN, JIANG WEN-MIAN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 204-208. article doi:10.7498/aps.50.204 10.7498/aps.50.204 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.204 204-208 //www.getgobooth.com/en/article/doi/10.7498/aps.50.209 Author(s): SUN JUN-SHENG, WU CHUAN-SONG <br/><p>The surface border of weldpool in MIG welding is irregular and the temperature in the pool is very high and is distributed extremely nonuniformly.The violent motion occur under the action of the electromagnetic force,the buoyancy force and the surface tension,etc.According to the bimodal distribution mode for arc current density with a large deformation of the pool surface,the calculation mode for electromagnetic force is developed and described in this paper.Numerical analysis is used to study the hydrodynamics behavior in the weldpool and the effects of welding technical parameters on fluid flow.The experiments show that the predicted results are in good agreement with experimental measurements.</p> <br/>Acta Physica Sinica. 2001 50(2): 209-216. Published 2001-01-05 Author(s): SUN JUN-SHENG, WU CHUAN-SONG <br/><p>The surface border of weldpool in MIG welding is irregular and the temperature in the pool is very high and is distributed extremely nonuniformly.The violent motion occur under the action of the electromagnetic force,the buoyancy force and the surface tension,etc.According to the bimodal distribution mode for arc current density with a large deformation of the pool surface,the calculation mode for electromagnetic force is developed and described in this paper.Numerical analysis is used to study the hydrodynamics behavior in the weldpool and the effects of welding technical parameters on fluid flow.The experiments show that the predicted results are in good agreement with experimental measurements.</p> <br/>Acta Physica Sinica. 2001 50(2): 209-216. Published 2001-01-05 THE ELECTROMAGNETIC FORCE AND ITS INFLUENCE ON THE WELDPOOL FLUID FLOW IN MIG WELDING SUN JUN-SHENG, WU CHUAN-SONG 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 209-216. article doi:10.7498/aps.50.209 10.7498/aps.50.209 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.209 209-216 //www.getgobooth.com/en/article/doi/10.7498/aps.50.217 Author(s): LI CUI-LIAN, LIU YOU-YAN <br/><p>Using the projection and Fourier transform methods,we have derived the diffraction formulas and discussed the rules of diffraction peaks and systematic absences for the one-dimensional Fibonacci-class quasilattices.Moreover,we have calculated and labeled the positions of the diffraction peaks of FC(1) and FC(3).In order to check our diffraction formulas,we extend the formulas to the FC(n) quasiperiodic superlattices.Comparing the present diffraction results of the FC(1) superlattice with the experimental data,we have found that most of them agree with each other but one of the spectra is not consistent.Particularily,we doubt that the peak (4,2) in the experiment should be a stronger peak.</p> <br/>Acta Physica Sinica. 2001 50(2): 217-222. Published 2001-01-05 Author(s): LI CUI-LIAN, LIU YOU-YAN <br/><p>Using the projection and Fourier transform methods,we have derived the diffraction formulas and discussed the rules of diffraction peaks and systematic absences for the one-dimensional Fibonacci-class quasilattices.Moreover,we have calculated and labeled the positions of the diffraction peaks of FC(1) and FC(3).In order to check our diffraction formulas,we extend the formulas to the FC(n) quasiperiodic superlattices.Comparing the present diffraction results of the FC(1) superlattice with the experimental data,we have found that most of them agree with each other but one of the spectra is not consistent.Particularily,we doubt that the peak (4,2) in the experiment should be a stronger peak.</p> <br/>Acta Physica Sinica. 2001 50(2): 217-222. Published 2001-01-05 THE DIFFRACTION PROPERTIES FOR THE ONE-DIMENSIONAL FIBONACCI-CLASS QUASILATTICES LI CUI-LIAN, LIU YOU-YAN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 217-222. article doi:10.7498/aps.50.217 10.7498/aps.50.217 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.217 217-222 //www.getgobooth.com/en/article/doi/10.7498/aps.50.223 Author(s): HOU SHI-MIN, TAO CHENG-GANG, LIU HONG-WEN, ZHAO XING-YU, LIU WEI-MIN, XUE ZENG-QUAN <br/><p>We have investigated the growth of gold nanoclusters on the surface of highly oriented pyrolytic graphite in ultrahigh vacuum.Studies by ultrahigh vacuum scanning tunneling microscopy indicated that the size distribution of gold clusters was very narrow and quasi-one-dimensional chains of gold nanoclusters of approximately 2 nm diameter were produced after annealed at 74℃.And gold nanowires made of different sized gold clusters could also be formed after annealed at 122℃.These results suggest the viability of a new route to the creation of ordered nanoscale structures.</p> <br/>Acta Physica Sinica. 2001 50(2): 223-226. Published 2001-01-05 Author(s): HOU SHI-MIN, TAO CHENG-GANG, LIU HONG-WEN, ZHAO XING-YU, LIU WEI-MIN, XUE ZENG-QUAN <br/><p>We have investigated the growth of gold nanoclusters on the surface of highly oriented pyrolytic graphite in ultrahigh vacuum.Studies by ultrahigh vacuum scanning tunneling microscopy indicated that the size distribution of gold clusters was very narrow and quasi-one-dimensional chains of gold nanoclusters of approximately 2 nm diameter were produced after annealed at 74℃.And gold nanowires made of different sized gold clusters could also be formed after annealed at 122℃.These results suggest the viability of a new route to the creation of ordered nanoscale structures.</p> <br/>Acta Physica Sinica. 2001 50(2): 223-226. Published 2001-01-05 STUDY ON GOLD NANOCLUSTERS AND GOLD NANOWIRES ON THE SURFACE OF HIGHLY ORIENTED PYROLYTIC GRAPHITE HOU SHI-MIN, TAO CHENG-GANG, LIU HONG-WEN, ZHAO XING-YU, LIU WEI-MIN, XUE ZENG-QUAN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 223-226. article doi:10.7498/aps.50.223 10.7498/aps.50.223 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.223 223-226 //www.getgobooth.com/en/article/doi/10.7498/aps.50.227 Author(s): LING ZHI-HUA <br/><p>We have investigated the polarization dependence of FT-IR of the stretching of CD2 in chiral alkyl chain of TFMHxPOCBC-D2(4-(trifluoromethylhexy-3-d2 carbonyl) phenyl 4′-octyloxybiphenyl caboxylate) with a homeotropically aligned cell.It is found that the polarization dependence of Sm-C and that of Sm-CA are different.Simulation calculation indicates that the rotation of CD2 around the alkyl chain is hindered.</p> <br/>Acta Physica Sinica. 2001 50(2): 227-232. Published 2001-01-05 Author(s): LING ZHI-HUA <br/><p>We have investigated the polarization dependence of FT-IR of the stretching of CD2 in chiral alkyl chain of TFMHxPOCBC-D2(4-(trifluoromethylhexy-3-d2 carbonyl) phenyl 4′-octyloxybiphenyl caboxylate) with a homeotropically aligned cell.It is found that the polarization dependence of Sm-C and that of Sm-CA are different.Simulation calculation indicates that the rotation of CD2 around the alkyl chain is hindered.</p> <br/>Acta Physica Sinica. 2001 50(2): 227-232. Published 2001-01-05 STUDY OF POLARIZED FT-IR FOR ANTIFERROELECTRIC LIQUID CRYSTAL TFMHxPOCBC-D2 IN A HOMEOTROPICALLY ALIGNED CELL LING ZHI-HUA 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 227-232. article doi:10.7498/aps.50.227 10.7498/aps.50.227 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.227 227-232 //www.getgobooth.com/en/article/doi/10.7498/aps.50.233 Author(s): LIU ZHU-HONG, HU FENG-XIA, WANG WEN-HONG, CHEN JING-LAN, WU GUANG-HENG, GAO SHU-XIA, AO LING <br/><p>The martensitic phase transformation temperature,Tm and the Curie temperature, TC, of polycrystalline samples Ni2+xMn1-x Ga(x=-0.1,0,0.08,0.13,0.18,0.2) and Ni2-xMn1+x/2Ga1+x/2(x=-0.1,0,0.04,0.06,0.1) have been investigated by measuring the temperature dependence of alternating-current susceptibility. It was found that, with the increase of Ni content,TC decreases and Tm increases for Ni2+xMn1-xGa, and both TC and Tm increase first and decrease afterwards for Ni2-xMn1+x/2Ga1+x/2. Stress-free and two-way thermoelastic shape memory, with 1.2% strain, has been found in single crystal Ni52Mn24Ga24. The deformation can be enhanced more than three times, up to 4.0% shrinkage with a bias field 1.2T applied along the measurement direction. The origin of large recoverable strain should be attributed to the low level of internal stress and the field-induced rearrangement of martensitic variants through twin boundary motion rather than the phase boundary motion.</p> <br/>Acta Physica Sinica. 2001 50(2): 233-238. Published 2001-01-05 Author(s): LIU ZHU-HONG, HU FENG-XIA, WANG WEN-HONG, CHEN JING-LAN, WU GUANG-HENG, GAO SHU-XIA, AO LING <br/><p>The martensitic phase transformation temperature,Tm and the Curie temperature, TC, of polycrystalline samples Ni2+xMn1-x Ga(x=-0.1,0,0.08,0.13,0.18,0.2) and Ni2-xMn1+x/2Ga1+x/2(x=-0.1,0,0.04,0.06,0.1) have been investigated by measuring the temperature dependence of alternating-current susceptibility. It was found that, with the increase of Ni content,TC decreases and Tm increases for Ni2+xMn1-xGa, and both TC and Tm increase first and decrease afterwards for Ni2-xMn1+x/2Ga1+x/2. Stress-free and two-way thermoelastic shape memory, with 1.2% strain, has been found in single crystal Ni52Mn24Ga24. The deformation can be enhanced more than three times, up to 4.0% shrinkage with a bias field 1.2T applied along the measurement direction. The origin of large recoverable strain should be attributed to the low level of internal stress and the field-induced rearrangement of martensitic variants through twin boundary motion rather than the phase boundary motion.</p> <br/>Acta Physica Sinica. 2001 50(2): 233-238. Published 2001-01-05 INVESTIGATION ON MARTENSITIC TRANSFORMATION AND FIELD-INDUCED TWO-WAY SHAPE MEMORY EFFECT OF Ni-Mn-Ga ALLOY LIU ZHU-HONG, HU FENG-XIA, WANG WEN-HONG, CHEN JING-LAN, WU GUANG-HENG, GAO SHU-XIA, AO LING 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 233-238. article doi:10.7498/aps.50.233 10.7498/aps.50.233 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.233 233-238 //www.getgobooth.com/en/article/doi/10.7498/aps.50.239 Author(s): LIU PING, XU WEN-LAN, LI ZHI-FENG, MIAO ZHONG-LIN, LU WEI <br/><p>The rigid-ion model with only eight or nine meaningful parameters is applied to calculate the dispersion relations of both ferroelectric and paraelectric phases in PbTiO3. Phonon frequencies and vibration mode at the zone center were obtained. The good agreement between our calculation and the previously mode with eighteen parameters is shown. A simple model for investigation of the soft modes is suggested.</p> <br/>Acta Physica Sinica. 2001 50(2): 239-243. Published 2001-01-05 Author(s): LIU PING, XU WEN-LAN, LI ZHI-FENG, MIAO ZHONG-LIN, LU WEI <br/><p>The rigid-ion model with only eight or nine meaningful parameters is applied to calculate the dispersion relations of both ferroelectric and paraelectric phases in PbTiO3. Phonon frequencies and vibration mode at the zone center were obtained. The good agreement between our calculation and the previously mode with eighteen parameters is shown. A simple model for investigation of the soft modes is suggested.</p> <br/>Acta Physica Sinica. 2001 50(2): 239-243. Published 2001-01-05 THE THEORETICAL CALCULATION ABOUT PHONON DISPERSION OF THE TETRAGONAL AND CUBIC PHASES IN PbTiO3 LIU PING, XU WEN-LAN, LI ZHI-FENG, MIAO ZHONG-LIN, LU WEI 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 239-243. article doi:10.7498/aps.50.239 10.7498/aps.50.239 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.239 239-243 //www.getgobooth.com/en/article/doi/10.7498/aps.50.244 Author(s): DAI YONG-BING, SHEN HE-SHENG, ZHANG ZHI-MING, HE XIAN-CHANG, HU XIAO-JUN, SUN FANG-HONG, XIN HAI-WEI <br/><p>The structure of diamond/silicon interface, which was formed by the contact and the subsequent relaxation of the unreconstructed (001) surfaces of diamond film and silicon substrate, has been investigated by molecular dynamics simulation.The interaction among atoms of the silicon/carbon binary system was described by Tersoff many-body empirical potential. Before relaxation, the ratios of silicon atoms to carbon atoms along [110] and [110] directions are both 3∶2 and the ratio of the total number of interfacial silicon atoms to that of carbon is 9∶4. After relaxation, the matching of diamond and silicon lattices has been changed: along[110] direction, a 3∶2 coincidence relation is roughly remained, but along [110] direction, a 1∶1 coincidence relation is approximately adopted. Accordingly, the ratio of the total number of interfacial silicon atoms to that of carbon is near 3∶2. The migration of partial silicon atoms, which were originally in the second layer, upward to the interface is responsible for such changes. The silicon lattice near the interface shows the tendency of disordering along [001] direction. The strong bonding between interfacial silicon and carbon atoms was found and Si-C bonds with an average length of 0.189 nm were formed. This study has confirmed that the main feature of lattice matching is the meeting of silicon atoms at and near the interface to the arrangement of interfacial carbon atoms.</p> <br/>Acta Physica Sinica. 2001 50(2): 244-250. Published 2001-01-05 Author(s): DAI YONG-BING, SHEN HE-SHENG, ZHANG ZHI-MING, HE XIAN-CHANG, HU XIAO-JUN, SUN FANG-HONG, XIN HAI-WEI <br/><p>The structure of diamond/silicon interface, which was formed by the contact and the subsequent relaxation of the unreconstructed (001) surfaces of diamond film and silicon substrate, has been investigated by molecular dynamics simulation.The interaction among atoms of the silicon/carbon binary system was described by Tersoff many-body empirical potential. Before relaxation, the ratios of silicon atoms to carbon atoms along [110] and [110] directions are both 3∶2 and the ratio of the total number of interfacial silicon atoms to that of carbon is 9∶4. After relaxation, the matching of diamond and silicon lattices has been changed: along[110] direction, a 3∶2 coincidence relation is roughly remained, but along [110] direction, a 1∶1 coincidence relation is approximately adopted. Accordingly, the ratio of the total number of interfacial silicon atoms to that of carbon is near 3∶2. The migration of partial silicon atoms, which were originally in the second layer, upward to the interface is responsible for such changes. The silicon lattice near the interface shows the tendency of disordering along [001] direction. The strong bonding between interfacial silicon and carbon atoms was found and Si-C bonds with an average length of 0.189 nm were formed. This study has confirmed that the main feature of lattice matching is the meeting of silicon atoms at and near the interface to the arrangement of interfacial carbon atoms.</p> <br/>Acta Physica Sinica. 2001 50(2): 244-250. Published 2001-01-05 A MOLECULAR DYNAMICS SIMULATION OF DIAMOND/SILICON(001) INTERFACE DAI YONG-BING, SHEN HE-SHENG, ZHANG ZHI-MING, HE XIAN-CHANG, HU XIAO-JUN, SUN FANG-HONG, XIN HAI-WEI 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 244-250. article doi:10.7498/aps.50.244 10.7498/aps.50.244 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.244 244-250 //www.getgobooth.com/en/article/doi/10.7498/aps.50.251 Author(s): WANG BI-BEN, WANG WAN-LU, LIAO KE-JUN, XIAO JIN-LONG, FANG LIANG <br/><p>The enhanced nucleation process of diamond by negative substrate bias was investigated by scanning electron microscopy and atomic force microscopy. The mechanism of enhanced joint adhesion of diamond nuclei on Si substrate by ion bombardment was theoretically approached, and the relationship between negative substrate bias and adhesion of diamond nuclei on Si substrate was given.</p> <br/>Acta Physica Sinica. 2001 50(2): 251-255. Published 2001-01-05 Author(s): WANG BI-BEN, WANG WAN-LU, LIAO KE-JUN, XIAO JIN-LONG, FANG LIANG <br/><p>The enhanced nucleation process of diamond by negative substrate bias was investigated by scanning electron microscopy and atomic force microscopy. The mechanism of enhanced joint adhesion of diamond nuclei on Si substrate by ion bombardment was theoretically approached, and the relationship between negative substrate bias and adhesion of diamond nuclei on Si substrate was given.</p> <br/>Acta Physica Sinica. 2001 50(2): 251-255. Published 2001-01-05 INFLUENCE OF ION BOMBARDING ON ADHESION FORCE OF DIAMOND NUCLEI ON Si SUBSTRATE WANG BI-BEN, WANG WAN-LU, LIAO KE-JUN, XIAO JIN-LONG, FANG LIANG 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 251-255. article doi:10.7498/aps.50.251 10.7498/aps.50.251 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.251 251-255 //www.getgobooth.com/en/article/doi/10.7498/aps.50.256 Author(s): WANG YU-XIA, GUO ZHEN, HE HAI-PING, CAO YING, TANG HONG-GUO <br/><p>SiC films were prepared on Si(111) substrates by annealing polystyrene gel films at temperature 950℃ in vacuum(10-3 Pa).Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD), Transmission electron microscopy(TEM).Raman scattering and X-ray photoelectron spectroscopy(XPS) were used to study the morphology of the surface, crystal structure. composition and chemical state of the element of the SiC films. It revealed that the films consisted of preferentially oriented crystalline 6H-SiC epilayer which grew along(0001) planes parallel to Si(111) planes. The ratio of Si to C was about 1 and there were some carbon and oxide contaminant species in the form of CH, CO and Si2O3 along with a small amount of adsorptive oxide at the surface of the films. The polycrystalline grains in the films grew cylindrically along c axis.Their maximum size was about 150nm. The film was smooth. dense and uniform with a thickness of about 0.3 μm. It was found that covering the polystyrene film with a Si plate could increase the quantity of SiC during anncaling.</p> <br/>Acta Physica Sinica. 2001 50(2): 256-261. Published 2001-01-05 Author(s): WANG YU-XIA, GUO ZHEN, HE HAI-PING, CAO YING, TANG HONG-GUO <br/><p>SiC films were prepared on Si(111) substrates by annealing polystyrene gel films at temperature 950℃ in vacuum(10-3 Pa).Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD), Transmission electron microscopy(TEM).Raman scattering and X-ray photoelectron spectroscopy(XPS) were used to study the morphology of the surface, crystal structure. composition and chemical state of the element of the SiC films. It revealed that the films consisted of preferentially oriented crystalline 6H-SiC epilayer which grew along(0001) planes parallel to Si(111) planes. The ratio of Si to C was about 1 and there were some carbon and oxide contaminant species in the form of CH, CO and Si2O3 along with a small amount of adsorptive oxide at the surface of the films. The polycrystalline grains in the films grew cylindrically along c axis.Their maximum size was about 150nm. The film was smooth. dense and uniform with a thickness of about 0.3 μm. It was found that covering the polystyrene film with a Si plate could increase the quantity of SiC during anncaling.</p> <br/>Acta Physica Sinica. 2001 50(2): 256-261. Published 2001-01-05 EPITAXIAL GROWTH OF (0001)ORIENTED 6H-SiC FILMS ON Si(111) SUBSTRATE BY ORGANIC SOL-GEL FILM ANNEALING WANG YU-XIA, GUO ZHEN, HE HAI-PING, CAO YING, TANG HONG-GUO 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 256-261. article doi:10.7498/aps.50.256 10.7498/aps.50.256 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.256 256-261 //www.getgobooth.com/en/article/doi/10.7498/aps.50.262 Author(s): LI HONG-WEI, WANG TAI-HONG <br/><p>We have designed a new type metal-semiconductor-metal structure with InAs self-assembled quantum dots. Hystereses loops were observed in DC current transport. With quantum dots(QDs) directly embedded beneath the GaAs-metal interface, the charge and discharge of electrons in the dots modulate the current to form hysteresis. For a single quantum dot, the charge and discharge can be thought as single-electron processes controlled by applied voltage. In this paper we analyzed the characteristics of charging and discharging processes for the ensemble of QDs as a whole. The discharging process was dominated by the change of tunneling rate with gate voltage. The charging process was controlled by forward current flowing though the diode. The calculated results indicate that the electrons trapped to the ground states of QDs give rise to charging effect. The excited states capture fewer electrons and influence the charging effect weakly.</p> <br/>Acta Physica Sinica. 2001 50(2): 262-267. Published 2001-01-05 Author(s): LI HONG-WEI, WANG TAI-HONG <br/><p>We have designed a new type metal-semiconductor-metal structure with InAs self-assembled quantum dots. Hystereses loops were observed in DC current transport. With quantum dots(QDs) directly embedded beneath the GaAs-metal interface, the charge and discharge of electrons in the dots modulate the current to form hysteresis. For a single quantum dot, the charge and discharge can be thought as single-electron processes controlled by applied voltage. In this paper we analyzed the characteristics of charging and discharging processes for the ensemble of QDs as a whole. The discharging process was dominated by the change of tunneling rate with gate voltage. The charging process was controlled by forward current flowing though the diode. The calculated results indicate that the electrons trapped to the ground states of QDs give rise to charging effect. The excited states capture fewer electrons and influence the charging effect weakly.</p> <br/>Acta Physica Sinica. 2001 50(2): 262-267. Published 2001-01-05 CURRENT TRANSPORT PROPERTIES OF GaAs SCHOTTKY DIODE CONTAINING InAs SELF-ASSEMBLED QUANTUM DOTS LI HONG-WEI, WANG TAI-HONG 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 262-267. article doi:10.7498/aps.50.262 10.7498/aps.50.262 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.262 262-267 //www.getgobooth.com/en/article/doi/10.7498/aps.50.268 Author(s): PAN BI-CAI <br/><p>We have developed a new Si-H tight-binding potential through introducing hydrogen atom into the previous silicon tight-binding potential model,in which the correction of environment around a Si-H bond is considered for the interaction between silicon and hydrogen.The testing results show good transferability,hence this new model can be used to do research on complicated silicon-hydrogen systems.</p> <br/>Acta Physica Sinica. 2001 50(2): 268-272. Published 2001-01-05 Author(s): PAN BI-CAI <br/><p>We have developed a new Si-H tight-binding potential through introducing hydrogen atom into the previous silicon tight-binding potential model,in which the correction of environment around a Si-H bond is considered for the interaction between silicon and hydrogen.The testing results show good transferability,hence this new model can be used to do research on complicated silicon-hydrogen systems.</p> <br/>Acta Physica Sinica. 2001 50(2): 268-272. Published 2001-01-05 TIGHT-BINDING POTENTIAL WITH CORRECTION OF BONDING ENVIRONMENT FOR SILICON-HYDROGEN PAN BI-CAI 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 268-272. article doi:10.7498/aps.50.268 10.7498/aps.50.268 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.268 268-272 //www.getgobooth.com/en/article/doi/10.7498/aps.50.273 Author(s): WANG REN-ZHI, ZHENG YONG-MEI, LI SHU-PING <br/><p>In free electron band model of three different crystal structures,face-centered cubic (fcc),body-centered cubic (bcc),and hexagonal close-packed (hcp) structures,we fine that the average energy of the four lowest band eigenvalues and the five sub-low band eigenvalues (called as average bond energy Em) is rather close to Fermi level EF.Meanwhile,we also confirm that this conclusion still holds for the practical band in some metals,such as Ti,Zr and Hf with hcp structure as well as Fe with bcc structure etc.,using ab initio pseudopotential and average bond energy methods.Thereby one can further understand the physical connotation of average bond energy Em.</p> <br/>Acta Physica Sinica. 2001 50(2): 273-277. Published 2001-01-05 Author(s): WANG REN-ZHI, ZHENG YONG-MEI, LI SHU-PING <br/><p>In free electron band model of three different crystal structures,face-centered cubic (fcc),body-centered cubic (bcc),and hexagonal close-packed (hcp) structures,we fine that the average energy of the four lowest band eigenvalues and the five sub-low band eigenvalues (called as average bond energy Em) is rather close to Fermi level EF.Meanwhile,we also confirm that this conclusion still holds for the practical band in some metals,such as Ti,Zr and Hf with hcp structure as well as Fe with bcc structure etc.,using ab initio pseudopotential and average bond energy methods.Thereby one can further understand the physical connotation of average bond energy Em.</p> <br/>Acta Physica Sinica. 2001 50(2): 273-277. Published 2001-01-05 STUDY ON PHYSICAL CONNOTATION OF AVERAGE BOND ENERGY Em WANG REN-ZHI, ZHENG YONG-MEI, LI SHU-PING 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 273-277. article doi:10.7498/aps.50.273 10.7498/aps.50.273 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.273 273-277 //www.getgobooth.com/en/article/doi/10.7498/aps.50.278 Author(s): WANG LI-MIN, LUO YING, MA BEN-KUN <br/><p>We calculated the electronic structure of double quantum-dot molecule with a generalized LCAO approach and the finite element method.Compared with real molecule,the quantum dot molecule can be in the form of covalent bonding or ionic bonding between the two same (or different) quantum dots under different conditions.The condition is related to the distance between the two quantum dots and the energy of each quantum dot.The effects of the potential and radius of the quantum dots on the electronic structure have also been studied with the finite element method.</p> <br/>Acta Physica Sinica. 2001 50(2): 278-286. Published 2001-01-05 Author(s): WANG LI-MIN, LUO YING, MA BEN-KUN <br/><p>We calculated the electronic structure of double quantum-dot molecule with a generalized LCAO approach and the finite element method.Compared with real molecule,the quantum dot molecule can be in the form of covalent bonding or ionic bonding between the two same (or different) quantum dots under different conditions.The condition is related to the distance between the two quantum dots and the energy of each quantum dot.The effects of the potential and radius of the quantum dots on the electronic structure have also been studied with the finite element method.</p> <br/>Acta Physica Sinica. 2001 50(2): 278-286. Published 2001-01-05 ELECTRONIC STRUCTURE OF DOUBLE QUANTUM-DOT MOLECULE WANG LI-MIN, LUO YING, MA BEN-KUN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 278-286. article doi:10.7498/aps.50.278 10.7498/aps.50.278 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.278 278-286 //www.getgobooth.com/en/article/doi/10.7498/aps.50.287 Author(s): LIU XUE-MING, ZHANG MING-DE, SUN XIAO-HAN, LIU LIN <br/><p>By employing the concept of photon flux,the evolution of the phase and photon flux in the eigenmode state in three-wave mixing,and the requirements for the initial phase and photon flux in this state,are studied in the paper.A special state in which there are only exchanges of the photon flux but no phase variations in the three-wave mixing process is investigated.An all-optical switch based on the eigenmode pushpull nonlinear-optical-mirror is presented,and the properties of this all-optical switch are numerically calculated.The numerical results show that the performance stability is extremely good,and the intensity and phase of the output signal beams can be easily realized and controlled.</p> <br/>Acta Physica Sinica. 2001 50(2): 287-292. Published 2001-01-05 Author(s): LIU XUE-MING, ZHANG MING-DE, SUN XIAO-HAN, LIU LIN <br/><p>By employing the concept of photon flux,the evolution of the phase and photon flux in the eigenmode state in three-wave mixing,and the requirements for the initial phase and photon flux in this state,are studied in the paper.A special state in which there are only exchanges of the photon flux but no phase variations in the three-wave mixing process is investigated.An all-optical switch based on the eigenmode pushpull nonlinear-optical-mirror is presented,and the properties of this all-optical switch are numerically calculated.The numerical results show that the performance stability is extremely good,and the intensity and phase of the output signal beams can be easily realized and controlled.</p> <br/>Acta Physica Sinica. 2001 50(2): 287-292. Published 2001-01-05 A NOVEL ALL-OPTICAL SWITCH BASED ON THE CASCADING OF SECOND-ORDER NONLINEARITY LIU XUE-MING, ZHANG MING-DE, SUN XIAO-HAN, LIU LIN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 287-292. article doi:10.7498/aps.50.287 10.7498/aps.50.287 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.287 287-292 //www.getgobooth.com/en/article/doi/10.7498/aps.50.293 Author(s): ZHANG XIAO-QING, G.M.SESSLER, XIA ZHONG-FU, ZHANG YE-WEN <br/><p>The characteristics of charge storage in APCVD Si3N4/thermal-grown SiO2 double layers electret films, charged by coroma were investigated by measurements of isothermal surface potential decay and thermally stimulated discharge(TSD).The results show that all of the samples have high charge stability at room temperature, at 300 and 60℃ under 95% of the relative humidity. The transport of the trapped charges due to external excitation for the negatively charged samples is basically controlled by the slow retrapping effect. However, the transport of detrapped positive charges due to external excitation can be described by a model of thermal ion emission.</p> <br/>Acta Physica Sinica. 2001 50(2): 293-298. Published 2001-01-05 Author(s): ZHANG XIAO-QING, G.M.SESSLER, XIA ZHONG-FU, ZHANG YE-WEN <br/><p>The characteristics of charge storage in APCVD Si3N4/thermal-grown SiO2 double layers electret films, charged by coroma were investigated by measurements of isothermal surface potential decay and thermally stimulated discharge(TSD).The results show that all of the samples have high charge stability at room temperature, at 300 and 60℃ under 95% of the relative humidity. The transport of the trapped charges due to external excitation for the negatively charged samples is basically controlled by the slow retrapping effect. However, the transport of detrapped positive charges due to external excitation can be described by a model of thermal ion emission.</p> <br/>Acta Physica Sinica. 2001 50(2): 293-298. Published 2001-01-05 CHARGE STORAGE AND TRANSPORTATION IN DOUBLE LAYERS OF Si3N4/SiO2 ELECTRET FILM BASED ON Si SUBSTRATE ZHANG XIAO-QING, G.M.SESSLER, XIA ZHONG-FU, ZHANG YE-WEN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 293-298. article doi:10.7498/aps.50.293 10.7498/aps.50.293 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.293 293-298 //www.getgobooth.com/en/article/doi/10.7498/aps.50.299 Author(s): WANG JI-SUO, FENG JIAN, ZHAN MING-SHENG <br/><p>Based on the fact that the charge is quantized in the mesoscopic circuit,the quantum theory of the mesoscopic inductance-coupling circuits and the condition for Coulomb blockade have been given in this paper,and the quantum fluctuations in the mesoscopic inductance coupling circuits have also been shown.</p> <br/>Acta Physica Sinica. 2001 50(2): 299-303. Published 2001-01-05 Author(s): WANG JI-SUO, FENG JIAN, ZHAN MING-SHENG <br/><p>Based on the fact that the charge is quantized in the mesoscopic circuit,the quantum theory of the mesoscopic inductance-coupling circuits and the condition for Coulomb blockade have been given in this paper,and the quantum fluctuations in the mesoscopic inductance coupling circuits have also been shown.</p> <br/>Acta Physica Sinica. 2001 50(2): 299-303. Published 2001-01-05 COULOMB BLOCKADE AND QUANTUM EFFECTS OF CHARGE IN A NON-DISSIPATIVE MESOSCOPIC INDUCTANCE-COUPLING CIRCUITS WANG JI-SUO, FENG JIAN, ZHAN MING-SHENG 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 299-303. article doi:10.7498/aps.50.299 10.7498/aps.50.299 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.299 299-303 //www.getgobooth.com/en/article/doi/10.7498/aps.50.304 Author(s): XIONG YI-MIN, SUN ZHE, CHEN XIAN-HUI <br/><p>Raman spectra at different temperatures are reported for K3Ba3C60.A systematic change of the Raman spectra with temperature is observed.The development of the linewidth and intensity for all modes with temperature is in sharp contrast to the case for pure C60.An anomalously large up-shift of 9 cm-1 between 20 K and room temperature for the pinch Ag(2) mode suggests the existence of hybridization between the C60 molecules and the intercalants.The relative intensity of the doublet of Ag(1) systemtically changes with decreasing temperature.</p> <br/>Acta Physica Sinica. 2001 50(2): 304-309. Published 2001-01-05 Author(s): XIONG YI-MIN, SUN ZHE, CHEN XIAN-HUI <br/><p>Raman spectra at different temperatures are reported for K3Ba3C60.A systematic change of the Raman spectra with temperature is observed.The development of the linewidth and intensity for all modes with temperature is in sharp contrast to the case for pure C60.An anomalously large up-shift of 9 cm-1 between 20 K and room temperature for the pinch Ag(2) mode suggests the existence of hybridization between the C60 molecules and the intercalants.The relative intensity of the doublet of Ag(1) systemtically changes with decreasing temperature.</p> <br/>Acta Physica Sinica. 2001 50(2): 304-309. Published 2001-01-05 TEMPERATURE DEPENDENCE OF RAMAN SCATTERING IN K3Ba3C60 XIONG YI-MIN, SUN ZHE, CHEN XIAN-HUI 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 304-309. article doi:10.7498/aps.50.304 10.7498/aps.50.304 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.304 304-309 //www.getgobooth.com/en/article/doi/10.7498/aps.50.310 Author(s): XU BO-WEI, YE FEI, DING GUO-HUI <br/><p>We consider a massless fermion interacting with the gauge field by Pauli interaction in which the coupling constant is dimensionless. The model is equivalent to the s=1/2 antiferromagnetic XXZ spin chain. The two flavours massless fermion of such model can describe the two-leg spin ladder system qualitatively, and there is no gapless exitation in such a system.</p> <br/>Acta Physica Sinica. 2001 50(2): 310-312. Published 2001-01-05 Author(s): XU BO-WEI, YE FEI, DING GUO-HUI <br/><p>We consider a massless fermion interacting with the gauge field by Pauli interaction in which the coupling constant is dimensionless. The model is equivalent to the s=1/2 antiferromagnetic XXZ spin chain. The two flavours massless fermion of such model can describe the two-leg spin ladder system qualitatively, and there is no gapless exitation in such a system.</p> <br/>Acta Physica Sinica. 2001 50(2): 310-312. Published 2001-01-05 ONE KIND OF THE GAUGE FIELD THEORY OF SPIN LADDERS XU BO-WEI, YE FEI, DING GUO-HUI 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 310-312. article doi:10.7498/aps.50.310 10.7498/aps.50.310 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.310 310-312 //www.getgobooth.com/en/article/doi/10.7498/aps.50.313 Author(s): GUO GUANG-HUA, R.Z.LEVITIN <br/><p>The temperature dependence of lattice constants a and c of intermetallic compund DyMn2Ge2 is measured in the temperature range 10-800K by using the X-ray method. The magnetoelastic anomaly of lattice constants a is observed at spontaneous magnetic phase transition from paramagnetic state to antiferromagnetic state. The ac magnetic susceptibility of DyMn2Ge2 is measured in the temperature range 4.2-200K. Low temperature magnetic phase transitions in DyMn2Ge2 are discussed in the molecular field approximation by taking into account of next nearest Mn-Mn interlayer exchange interaction. The temperature dependence of magnetization and magnetic curves at different temperatures of DyMn2Ge2 single crystal are calculated. Theoretical calculation shows that the observed field-induced magnetic phase transition in DyMn2Ge2 single crystal at temperature lower than 33K is the transition from ferrimagnetic state into intermediate state.</p> <br/>Acta Physica Sinica. 2001 50(2): 313-318. Published 2001-01-05 Author(s): GUO GUANG-HUA, R.Z.LEVITIN <br/><p>The temperature dependence of lattice constants a and c of intermetallic compund DyMn2Ge2 is measured in the temperature range 10-800K by using the X-ray method. The magnetoelastic anomaly of lattice constants a is observed at spontaneous magnetic phase transition from paramagnetic state to antiferromagnetic state. The ac magnetic susceptibility of DyMn2Ge2 is measured in the temperature range 4.2-200K. Low temperature magnetic phase transitions in DyMn2Ge2 are discussed in the molecular field approximation by taking into account of next nearest Mn-Mn interlayer exchange interaction. The temperature dependence of magnetization and magnetic curves at different temperatures of DyMn2Ge2 single crystal are calculated. Theoretical calculation shows that the observed field-induced magnetic phase transition in DyMn2Ge2 single crystal at temperature lower than 33K is the transition from ferrimagnetic state into intermediate state.</p> <br/>Acta Physica Sinica. 2001 50(2): 313-318. Published 2001-01-05 SPONTANEOUS AND FIELD-INDUCED MAGNETIC PHASE TRANSITIONS IN THE INTERMETALLIC COMPOUND DyMn2Ge2 GUO GUANG-HUA, R.Z.LEVITIN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 313-318. article doi:10.7498/aps.50.313 10.7498/aps.50.313 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.313 313-318 //www.getgobooth.com/en/article/doi/10.7498/aps.50.319 Author(s): CHEN WEI, ZHONG WEI, PAN CHENG, CHANG HONG, DU YOU-WEI <br/><p>Polycrystalline samples of La0.8-xCa0.2MnO3(x=0,0.01,0.03,0.05,0.08,0.1) were synthesized using a sol-gel technique. Structure analysis, morphology observation and magnetic measurement have been used to study the effect of vacuum concentration of La3+ on the Curie temperature and magnetic entropy change of La0.8-xCa0.2MnO3. The experimental results show that by tuning the vacuum concentration of La\+\{3+\}, the materials could exhibit very different Curie temperatures (from 180 to 260K). All the samples in this paper have large magnetic entropy change, especially for La0.77Ca0.2MnO3 sintered at 1100℃, which has a very large magnetic entropy change ΔSM=3.76J/kg·K under the magnetic field H=1.0T. The phenomenon of large magnetic entropy change, high Curie temperature, high electrical resistivity and high chemical stability make this material a suitable candidates for refrigerants at high temperature.</p> <br/>Acta Physica Sinica. 2001 50(2): 319-323. Published 2001-01-05 Author(s): CHEN WEI, ZHONG WEI, PAN CHENG, CHANG HONG, DU YOU-WEI <br/><p>Polycrystalline samples of La0.8-xCa0.2MnO3(x=0,0.01,0.03,0.05,0.08,0.1) were synthesized using a sol-gel technique. Structure analysis, morphology observation and magnetic measurement have been used to study the effect of vacuum concentration of La3+ on the Curie temperature and magnetic entropy change of La0.8-xCa0.2MnO3. The experimental results show that by tuning the vacuum concentration of La\+\{3+\}, the materials could exhibit very different Curie temperatures (from 180 to 260K). All the samples in this paper have large magnetic entropy change, especially for La0.77Ca0.2MnO3 sintered at 1100℃, which has a very large magnetic entropy change ΔSM=3.76J/kg·K under the magnetic field H=1.0T. The phenomenon of large magnetic entropy change, high Curie temperature, high electrical resistivity and high chemical stability make this material a suitable candidates for refrigerants at high temperature.</p> <br/>Acta Physica Sinica. 2001 50(2): 319-323. Published 2001-01-05 CURIE TEMPERATURE AND MAGNETOCALORIC EFFECT OF POLYCRYSTALLINE La0.8-xCa0.2MnO3 CHEN WEI, ZHONG WEI, PAN CHENG, CHANG HONG, DU YOU-WEI 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 319-323. article doi:10.7498/aps.50.319 10.7498/aps.50.319 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.319 319-323 //www.getgobooth.com/en/article/doi/10.7498/aps.50.324 Author(s): LI XIAO-HONG, WEI FU-LIN, YANG ZHENG <br/><p>A model of a chain of oblate ellipsoids is proposed for magnetization reversal of barium ferrite particles. The angular dependences of coercivity and critical field were calculated with the consideration of the uniaxial magnetocrystalline anisotropy, the shape anisotropy, the interaction anisotropy of the ellipsoids, as well as the number of ellipsoids. This model could be used to explain the magnetization reversal mechanism of the oriented Ba ferrite particulate media.</p> <br/>Acta Physica Sinica. 2001 50(2): 324-328. Published 2001-01-05 Author(s): LI XIAO-HONG, WEI FU-LIN, YANG ZHENG <br/><p>A model of a chain of oblate ellipsoids is proposed for magnetization reversal of barium ferrite particles. The angular dependences of coercivity and critical field were calculated with the consideration of the uniaxial magnetocrystalline anisotropy, the shape anisotropy, the interaction anisotropy of the ellipsoids, as well as the number of ellipsoids. This model could be used to explain the magnetization reversal mechanism of the oriented Ba ferrite particulate media.</p> <br/>Acta Physica Sinica. 2001 50(2): 324-328. Published 2001-01-05 STUDY ON MAGNETIZATION REVERSAL OF BARIUM FERRITE PARTICLES LI XIAO-HONG, WEI FU-LIN, YANG ZHENG 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 324-328. article doi:10.7498/aps.50.324 10.7498/aps.50.324 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.324 324-328 //www.getgobooth.com/en/article/doi/10.7498/aps.50.329 Author(s): WANG DIAN-YUAN, XIE PING-BO, ZHANG WEI-PING, LOU LI-REN, XIA SHANG-DA <br/><p>By Application of the V-F-B model which is obtained by combining the Vasquez-Flint (V-F) model for donor-acceptor energy transfer and the model of Burshtein for donor-donor energy migration, the experimental luminescence decay curves of 4S3/2 state of Er3+ in LaF3 at 295K for four different concentrations are re-simulated successfully.It is found that in this system the donor-acceptor interaction is dipole-dipole interaction,and that the donor-acceptor interaction constant CDA is 4.75×10-41cm6/s. The results are all in agreement with the previous results of Okamoto. However, the hopping time τ0 obtained from the above simulation in proportional to xD-1.237 (xD is the donor concentration), which is different from the theoretical dependence on the donor concentration (that is τ0∝xD-2). In addition, by considering donor-acceptor energy transfer and donor-donor energy migration within the V-F model at the same time, we obtain the estimated values of the hopping time τ0′ for four different concentrations, which are in reasonable agreement with the values of τ0 obtained from the above simulation.It seems that the V-F-B model is rather self-consistent.</p> <br/>Acta Physica Sinica. 2001 50(2): 329-334. Published 2001-01-05 Author(s): WANG DIAN-YUAN, XIE PING-BO, ZHANG WEI-PING, LOU LI-REN, XIA SHANG-DA <br/><p>By Application of the V-F-B model which is obtained by combining the Vasquez-Flint (V-F) model for donor-acceptor energy transfer and the model of Burshtein for donor-donor energy migration, the experimental luminescence decay curves of 4S3/2 state of Er3+ in LaF3 at 295K for four different concentrations are re-simulated successfully.It is found that in this system the donor-acceptor interaction is dipole-dipole interaction,and that the donor-acceptor interaction constant CDA is 4.75×10-41cm6/s. The results are all in agreement with the previous results of Okamoto. However, the hopping time τ0 obtained from the above simulation in proportional to xD-1.237 (xD is the donor concentration), which is different from the theoretical dependence on the donor concentration (that is τ0∝xD-2). In addition, by considering donor-acceptor energy transfer and donor-donor energy migration within the V-F model at the same time, we obtain the estimated values of the hopping time τ0′ for four different concentrations, which are in reasonable agreement with the values of τ0 obtained from the above simulation.It seems that the V-F-B model is rather self-consistent.</p> <br/>Acta Physica Sinica. 2001 50(2): 329-334. Published 2001-01-05 A STUDY ON ENERGY TRANSFER AND ENERGY MIGRATION MODELS FOR RE IONS LUMINESCENCE SYSTEM WANG DIAN-YUAN, XIE PING-BO, ZHANG WEI-PING, LOU LI-REN, XIA SHANG-DA 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 329-334. article doi:10.7498/aps.50.329 10.7498/aps.50.329 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.329 329-334 //www.getgobooth.com/en/article/doi/10.7498/aps.50.335 Author(s): FENG YAN, SONG FENG, ZHAO LI-JUAN, ZHANG CHAO-BO, GUO HONG-CANG, ZHANG GUANG-YIN <br/><p>Upconversion fluorescence in Nd:YVO4 crystal under a laser diode (LD) pump was investigated. It is proved that the predominant mechanism for excitation of 4G7/2 level is an energy transfer upconversion. Then,a theoretical approach to upconversion effect on LD pumped Nd:YVO4 laser is given.In addition,the role of upconversion in thermal effect is discussed in detail.</p> <br/>Acta Physica Sinica. 2001 50(2): 335-340. Published 2001-01-05 Author(s): FENG YAN, SONG FENG, ZHAO LI-JUAN, ZHANG CHAO-BO, GUO HONG-CANG, ZHANG GUANG-YIN <br/><p>Upconversion fluorescence in Nd:YVO4 crystal under a laser diode (LD) pump was investigated. It is proved that the predominant mechanism for excitation of 4G7/2 level is an energy transfer upconversion. Then,a theoretical approach to upconversion effect on LD pumped Nd:YVO4 laser is given.In addition,the role of upconversion in thermal effect is discussed in detail.</p> <br/>Acta Physica Sinica. 2001 50(2): 335-340. Published 2001-01-05 UPCONVERSION IN Nd:YVO4 CRYSTAL UNDER LD PUMP AND ITS INFLUENCE FENG YAN, SONG FENG, ZHAO LI-JUAN, ZHANG CHAO-BO, GUO HONG-CANG, ZHANG GUANG-YIN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 335-340. article doi:10.7498/aps.50.335 10.7498/aps.50.335 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.335 335-340 //www.getgobooth.com/en/article/doi/10.7498/aps.50.341 Author(s): YANG HE-QING, WANG XUAN, LIU SHOU-XIN, LI YONG-FANG, ZHANG LIANG-YING, YAO XI <br/><p>C-nanoparticles with a diameter smaller than 60 nm in xAl2O3-xP2O5-100SiO2(x=0.25—2) gel-glasses have been prepared by sol-gel process. The gels synthesized through partial hydrolysis of PO(OC2H5)3,Al(NO3)3·9H2O and Si(OC2H5)4 were heated at 400℃ or 450℃ in air atmosphere or from 300 to 700℃ in N2 atmosphere, in which —OC2H5 were carbonized to form nanosized C particles. These C-nanoparticles-doped gel-glasses were characterized by optical absorption and TEM.The optical absorption edge shifts to the higher-energy side as the size of the C particle decreases. This phenomenon is interpreted in terms of a quantum confinement effect of electron and hole in the C-nanoparticles. The C-nanoparticles structures were found to be amorphous carbon in the gel-glasses by electron diffraction pattern.</p> <br/>Acta Physica Sinica. 2001 50(2): 341-346. Published 2001-01-05 Author(s): YANG HE-QING, WANG XUAN, LIU SHOU-XIN, LI YONG-FANG, ZHANG LIANG-YING, YAO XI <br/><p>C-nanoparticles with a diameter smaller than 60 nm in xAl2O3-xP2O5-100SiO2(x=0.25—2) gel-glasses have been prepared by sol-gel process. The gels synthesized through partial hydrolysis of PO(OC2H5)3,Al(NO3)3·9H2O and Si(OC2H5)4 were heated at 400℃ or 450℃ in air atmosphere or from 300 to 700℃ in N2 atmosphere, in which —OC2H5 were carbonized to form nanosized C particles. These C-nanoparticles-doped gel-glasses were characterized by optical absorption and TEM.The optical absorption edge shifts to the higher-energy side as the size of the C particle decreases. This phenomenon is interpreted in terms of a quantum confinement effect of electron and hole in the C-nanoparticles. The C-nanoparticles structures were found to be amorphous carbon in the gel-glasses by electron diffraction pattern.</p> <br/>Acta Physica Sinica. 2001 50(2): 341-346. Published 2001-01-05 SYNTHESIS AND QUANTUM SIZE EFFECT OF CARBON NANOPARTICLES DOPED IN GEL-GLASSES YANG HE-QING, WANG XUAN, LIU SHOU-XIN, LI YONG-FANG, ZHANG LIANG-YING, YAO XI 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 341-346. article doi:10.7498/aps.50.341 10.7498/aps.50.341 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.341 341-346 //www.getgobooth.com/en/article/doi/10.7498/aps.50.347 Author(s): LU MING-ZHU, WAN MING-XI, SHI YU <br/><p>This paper mainly deals with problems of optimal field pattern control to the field conjugate direct synthesis of phased-array ultrasound hyperthermia. First,the rational optimal objective function for acoustic field pattern is put forward. Then, two optimal algorithms for global optimization are proposed. One is the genetic algorithm for constructing acoustic field pattern control and the other is the eigenvector algorithm for the same purpose. The simulation is performed with these two algorithms, genetic algorithm and eigenvector algorithm. Eventually, the objective of optimal field pattern control is achieved successfully. The genetic algorithm has better characteristics as compared with the eigenvector algorithm.</p> <br/>Acta Physica Sinica. 2001 50(2): 347-353. Published 2001-01-05 Author(s): LU MING-ZHU, WAN MING-XI, SHI YU <br/><p>This paper mainly deals with problems of optimal field pattern control to the field conjugate direct synthesis of phased-array ultrasound hyperthermia. First,the rational optimal objective function for acoustic field pattern is put forward. Then, two optimal algorithms for global optimization are proposed. One is the genetic algorithm for constructing acoustic field pattern control and the other is the eigenvector algorithm for the same purpose. The simulation is performed with these two algorithms, genetic algorithm and eigenvector algorithm. Eventually, the objective of optimal field pattern control is achieved successfully. The genetic algorithm has better characteristics as compared with the eigenvector algorithm.</p> <br/>Acta Physica Sinica. 2001 50(2): 347-353. Published 2001-01-05 STUDY ON THE OPTIMAL FIELD PATTERN CONTROL TO THE FIELD CONJUGATE DIRECT SYNTHESIS OF PHASED-ARRAY ULTRASOUND HYPERTHERMIA LU MING-ZHU, WAN MING-XI, SHI YU 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 347-353. article doi:10.7498/aps.50.347 10.7498/aps.50.347 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.347 347-353 //www.getgobooth.com/en/article/doi/10.7498/aps.50.354 Author(s): ZHANG XIONG, XIE GUANG-ZHONG, ZHAO GANG, MA LI, YI JI-DONG, BAI JIN-MING <br/><p>We have collected 29 gamma-ray-loud blazars (16 BL Lac objects and 13 flat-spectrum radio quasars) with both observed near-IR and γ-ray flux densitees, with the following main results:(1)there is a very strong correlation between Fγ and FIR in the low state, and a weaker but also significant correlation between Fγ and FIR in the high state for 23 objects with both high and low state fluxes; (2) there is a very significant correlation between Fγ and FIR in the low state, and a weak correlation between Fγ and FIR in the high state for 29 sources; (3) there is a correlation between Fγ and Fx, but not between Fγ and F0, and FR for both the low and high state of 26 sources; (4) there is a strong correlation between Fγ and FIR in the low and high states for 15 BL Lac objects, but not for 11 flat-spectrum radio quasars. Possible constraints on the γ-ray emission mechanism are discussed.We suggest that the main gamma-ray radiation mechanism is probably the synchrotron self-Compton process.The inverse Compton scattering of the radiation from hot circumnuclear dust with Tg=2000K, which is located within the region of r≈3pc, by beamed ultrarelativistic electrons is likely to be an important complementary mechanism.In addition, the γ-ray emission may be somewhat different for BL Lac objects and flat-spectrum radio quasars.</p> <br/>Acta Physica Sinica. 2001 50(2): 354-360. Published 2001-01-05 Author(s): ZHANG XIONG, XIE GUANG-ZHONG, ZHAO GANG, MA LI, YI JI-DONG, BAI JIN-MING <br/><p>We have collected 29 gamma-ray-loud blazars (16 BL Lac objects and 13 flat-spectrum radio quasars) with both observed near-IR and γ-ray flux densitees, with the following main results:(1)there is a very strong correlation between Fγ and FIR in the low state, and a weaker but also significant correlation between Fγ and FIR in the high state for 23 objects with both high and low state fluxes; (2) there is a very significant correlation between Fγ and FIR in the low state, and a weak correlation between Fγ and FIR in the high state for 29 sources; (3) there is a correlation between Fγ and Fx, but not between Fγ and F0, and FR for both the low and high state of 26 sources; (4) there is a strong correlation between Fγ and FIR in the low and high states for 15 BL Lac objects, but not for 11 flat-spectrum radio quasars. Possible constraints on the γ-ray emission mechanism are discussed.We suggest that the main gamma-ray radiation mechanism is probably the synchrotron self-Compton process.The inverse Compton scattering of the radiation from hot circumnuclear dust with Tg=2000K, which is located within the region of r≈3pc, by beamed ultrarelativistic electrons is likely to be an important complementary mechanism.In addition, the γ-ray emission may be somewhat different for BL Lac objects and flat-spectrum radio quasars.</p> <br/>Acta Physica Sinica. 2001 50(2): 354-360. Published 2001-01-05 STUDY OF GAMMA-RAY AND NEAR-INFRARED EMISSION OF GAMMA-RAY-LOUD BLAZARS OBJECT ZHANG XIONG, XIE GUANG-ZHONG, ZHAO GANG, MA LI, YI JI-DONG, BAI JIN-MING 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 354-360. article doi:10.7498/aps.50.354 10.7498/aps.50.354 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.354 354-360 //www.getgobooth.com/en/article/doi/10.7498/aps.50.361 Author(s): SHI DONG-XIA, SONG YAN-LIN, ZHANG HAO-XU, XIE SI-SHEN, PANG SHI-JIN, GAO HONG-JUN <br/><p>Ultrahigh-density data storage on a 3-phenyl-1-ureidonitrile (PUN) thin film was performed using a scanning tunneling microscope. The recorded marks of 0.8 nm in diameter were obtained when voltage pulses of 4 V for 10ms were applied between the STM tip and highly ordered pyrolytic graphite substrate. The current-voltage relations at the local regions of the films indicate that the recorded region is conductive and the unrecorded region is in a high impedance state. A possible mechanism of this data storage was suggested and discussed.</p> <br/>Acta Physica Sinica. 2001 50(2): 361-364. Published 2001-01-05 Author(s): SHI DONG-XIA, SONG YAN-LIN, ZHANG HAO-XU, XIE SI-SHEN, PANG SHI-JIN, GAO HONG-JUN <br/><p>Ultrahigh-density data storage on a 3-phenyl-1-ureidonitrile (PUN) thin film was performed using a scanning tunneling microscope. The recorded marks of 0.8 nm in diameter were obtained when voltage pulses of 4 V for 10ms were applied between the STM tip and highly ordered pyrolytic graphite substrate. The current-voltage relations at the local regions of the films indicate that the recorded region is conductive and the unrecorded region is in a high impedance state. A possible mechanism of this data storage was suggested and discussed.</p> <br/>Acta Physica Sinica. 2001 50(2): 361-364. Published 2001-01-05 ULTRAHIGH-DENSITY DATA STORAGE ON AN ORGANIC MONOMER 3-PHENYL-1-UREIDONITRILE THIN FILM SHI DONG-XIA, SONG YAN-LIN, ZHANG HAO-XU, XIE SI-SHEN, PANG SHI-JIN, GAO HONG-JUN 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 361-364. article doi:10.7498/aps.50.361 10.7498/aps.50.361 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.361 361-364 //www.getgobooth.com/en/article/doi/10.7498/aps.50.365 Author(s): JIN ZHAN, ZHANG JIE <br/><p>High temperature, high density and strong magnetic fields in plasmas produced by ultra-high intensity and ultrashort laser pulses are similar to the main characteristics of astrophysical plasmas. This makes it possible to simulate some astrophysical processes at laboratories. This paper presents our theoretic simulation of aluminum emission spectra in astrophysical plasmas. It can be concluded that using laser produced plasmas, we can obtain rich information on astrophysical spectroscopy, which is unobservable for astronomer.</p> <br/>Acta Physica Sinica. 2001 50(2): 365-368. Published 2001-01-05 Author(s): JIN ZHAN, ZHANG JIE <br/><p>High temperature, high density and strong magnetic fields in plasmas produced by ultra-high intensity and ultrashort laser pulses are similar to the main characteristics of astrophysical plasmas. This makes it possible to simulate some astrophysical processes at laboratories. This paper presents our theoretic simulation of aluminum emission spectra in astrophysical plasmas. It can be concluded that using laser produced plasmas, we can obtain rich information on astrophysical spectroscopy, which is unobservable for astronomer.</p> <br/>Acta Physica Sinica. 2001 50(2): 365-368. Published 2001-01-05 STUDY OF ALUMINUM EMISSION SPECTRA IN ASTROPHYSICAL PLASMAS JIN ZHAN, ZHANG JIE 2001-01-05 Personal use only, all commercial or other reuse prohibited Acta Physica Sinica. 2001 50(2): 365-368. article doi:10.7498/aps.50.365 10.7498/aps.50.365 Acta Physica Sinica 50 2 2001-01-05 //www.getgobooth.com/en/article/doi/10.7498/aps.50.365 365-368

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