检索结果-南通市图书馆

Josephson Effect in MgB_(2): Large I_(c)R_(N) Product and Superconducting Energy Gap

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第9期18卷 1254-1255页

作者： XUAN Yi LI Zhuang-Zhi TAO Hong-Jie REN Zhi-An che guang-can ZHAO Bai-Ru ZHAO Zhong-Xian National Laboratory for Superconductivity Institute of Physics and Center for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080

We report on the observation of the Josephson effect on the newly discovered superconductor MgB_(2) with the breakjunction technique. Similar to conventional superconductors, the I-V curve can be fitted with the resistively shunted junction model including the noise effect, and a large characteristic voltage V_(c)= I_(c)R_(N) = 9.6meV was obtained. The energy gap determined by the Ambegaokar-Baratoff relation with the fitted Vc is very consistent with the Bardeen-Cooper-Schrieffer weak-coupling value. Our result implies that the superconductor MgB_(2) is a promising material for Josephson device applications.

关键词： technique. value. Josephson

Structural Properties of MgB2 Superconductors with a Critical Current Density Greater than 10^(5)A/cm^(2)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第5期18卷 680-683页

作者： LI Jian-Qi LI Long ZHOU Yu-Qing REN Zhi-An che guang-can ZHAO Zhong-Xian National Laboratory for Superconductivity Institute of PhysicsChinese Academy of SciencesBeijing 100080 Department of Physics Ningxia UniversityYinchuan 750021

Structural features of MgB2 superconductors prepared under different conditions have been analysed by means of transmission electron *** MgB_(2) crystal is identified to have a hexagonal structure with the space group of P6/*** materials synthesized under a high pressure of 6 Gpa are made of regularly stacked grains as large as a few microns in *** faults and microstructure properties of grain boundaries either with or without impurities,appearing in a sample with the critical current density greater than 10^(5)A/cm^(2),have been systematically investigated.

关键词： MgB2 (5) Superconductor

Superconductivity of(R_(0.4)Pr_(0.6))_(0.5)Ca_(0.5)Ba_(2)Cu_(3)O_(7-δ)(R=La,Pr,Nd,Sm,Eu,Gd and Y)Prepared Under High Pressure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第5期18卷 684-686页

作者： XIONG Han che guang-can YAO Yu-Shu NI Yong-Ming LIU Zhen-Xing JIA Shun-Lian DONG cheng ZHAO Zhong-Xian National Laboratory for Superconductivity Institute of Physics and Centre for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080

The nearly single phase(R_(0.4)Pr_(0.6))_(0.5)Ca_(0.5)Ba_(2)Cu_(3)O_(7-δ)compounds(R=La,Pr,Nd,Sm,Eu,Gd and Y)with Tc about 100 K were prepared under high pressure and high temperature using the cubic anvil *** Tc is much higher than that of the traditional R-123 superconductors without doping Ca on the rare-earth *** various rare earths with different ionic radius,the(R_(0.4)Pr_(0.6))_(0.5)Ca_(0.5)Ba_(2)Cu_(3)O_(7-δ)compounds have almost the same critical *** is different from the result of the ion-size effect of rare-earth ions in R1-xPrxBa2Cu3O7-δ*** results show that Pr has the same properties as other rare earths in the 123-phase compounds due to the doping of Ca.

关键词： temperature. rare (0)

Epitaxial Growth of Bi_(2)Sr_(2-x)LaxCu_(1)O_(6+δ) Thin Films by In-Situ dc Magnetron Sputtering

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1998年第5期15卷 373-375页

作者： ZHANG Ying-zi YANG Duo-gui LI Lin ZHAO Bai-ru JIA Shun-lian cheN Hong WU Fei che guang-can ZHAO Zhong-xian National Laboratory for Superconductivity Institute of Physics&Centre for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080

Bi_(2)Sr_(2-x)LaxCu_(1)O_(6+δ)(La-2201)thin films were successfully prepared on(100)SrTiO_(3) and(100)LaAIO_(3) substrates by in-situ dc-magnetron sputtering process.A series compensated 2201 targets of La^(3+)substitution contents for Sr^(2+)were studied for growing 2201 phase thin *** superconducting zero resistance temperature T_(c,0) reached 19K.X-ray diffraction analyses showed that films oriented with c-axis perpendicular to the substrate surface and their lattice parameters are around 2.43-2.46nm.Ф-scan and rocking curve show a good epitaxial growth and crystallisation of the films.

关键词： process. substitution perpendicular

Superconducting Properties of MgB_(2) Prepared by High Pressure and Ambient Pressure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第4期18卷 589-591页

作者： REN Zhi-An che guang-can ZHAO Zhong-Xian cheN Hong DONG cheng NI Yong-Ming JIA Shun-Lian WEN Hai-Hu National Laboratory for Superconductivity Institute of Physics and Center for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080

The new superconductor MgB_(2) has been prepared by two ways: high pressure and ambient pressure synthesis. Their superconducting properties were measured and compared. It is found that the sample prepared by high pressure is much denser than that prepared under ambient pressure. Accordingly the high pressure sample has a very narrow transition width and a much higher bulk critical current density.

关键词： synthesis. ambient superconductor

Strong Quantum Fluctuation of Vortices in Bulk Samples of the New Superconductor MgB_(2)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第6期18卷 816-819页

作者： WEN Hai-Hu LI Shi-Liang ZHAO Zhi-Wen NI Yong-Ming REN Zhi-An che guang-can YANG Hai-Peng LIU Zhi-Yong ZHAO Zhong-Xian National Laboratory for Superconductivity Institute of Physics and Center for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080

By using transport and magnetic measurement,the upper critical field H_(c2)(T)and the irreversibility line Hirr(T)has been determined.A big separation between H_(c2)(0)and Hirr(0)has been found showing the existence of a quantum vortex liquid state induced by quantum fluctuation of vortices in the new superconductor MgB_(2).Further investigation on the magnetic relaxation shows that both the quantum tunneling and the thermally activated flux creep depends weakly on ***,when the melting field Hirr is approached,a drastic rise of the relaxation rate is *** may indicate that the melting of the vortex matter at a finite temperature is also induced by the quantum fluctuation of vortices.

关键词： temperature. quantum relaxation

Low Temperature Specific Heat of Superconducting MgB_(2)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第6期18卷 820-822页

作者： LUO Jian-Lin ZHANG Jie cheN Zhao-Jia BAI Hai-Yang WANG Yu-Peng MENG Ji-Bao JIN Duo REN Zhi-An che guang-can ZHAO Zhong-Xian Laboratory of Extreme Condition Physics Institute of Physics and Center for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080 National Laboratory for Superconductivity Institute of Physics and Center for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080 Department of Physics Chongqing UniversityChongqing 400044

The specific heat of the recently discovered superconductor MgB_(2) has been measured at temperatures ranging from 4.5 to 80 *** anomalyΔC at Tc is clearly *** total specific heat in normal state can be well fitted by electronic and phonon *** Debye temperatureθD is obtained to be 737 K,much larger than other intermetallic *** state electronic specific heat coefficientγis found to be 2.48±0.5 mJ/mol.K^(2) andΔC/γTc is between 1.41 and 2.15.

关键词： intermetallic superconductor electronic

Defects in phospholipase C zeta cause polyspermy and low fertilization after conventional IVF:not just ICSI failure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2024年第2期26卷 175-182页

作者： Jian-Fang che Hui-Xia Wu Si-Cong Zeng Yue-Ren Wu Jing Dai De-Hua cheng Fei Gong guang-Xiu Lu Ge Lin can Dai School of Medicine Hunan Normal UniversityChangsha 410013China Reproductive and Genetic Hospital of CITIC-Xiangya Changsha 410008China Clinical Research Center for Reproduction and Genetics in Hunan Province Changsha 410078China National Engineering and Research Center of Human Stem Cell Changsha 410205China

Phospholipase C zeta(PLC)is a key sperm-borne oocyte-activating factor that triggers Ca^(2+)oscillations and the subsequent block to polyspermy following gamete *** in PLCZ1,the gene encoding PLCζ,cause male infertility and intracytoplasmic sperm injection(ICSI)fertilization failure;and PLCζ expression and localization patterns are significantly correlated with ICSI fertilization rate(FR).However,in conventional in vitro fertilization(cIVF),whether and how sperm PLCζ affects fertilization remain ***,we identified one previously reported and two novel PLCZ1 mutations associated with polyspermy in vitro that are characterized by excessive sperm-zona binding and a delay in pronuclei(PN)*** staining and oocyte activation testing revealed that virtually all spermatozoa from patients lacked functional PLCζ and were thus unable to evoke Ca^(2+) *** with an artificial oocyte activation treatment successfully rescued the polyspermic phenotype and resulted in a live ***,we analyzed PLCζ in an additional 58 males after cIVF treatment in the Reproductive and Genetic Hospital of CiTiC-Xiangya(Changsha,China)between February 2019 and January *** found that the proportion of spermatozoa that expressed PLCζ was positively correlated with both 2PN rate and total *** optimal cutoff value below which males were likely to experience low FR(total FR≤30%)after clVF was 56.7%for the proportion of spermatozoa expressing *** study expands the mutation and the phenotypic spectrum of PLCZ1 and further suggests that PLCζ constitutes a promising biomarker for identifying low FRs cases in cIVF due to sperm-related oocyte activation deficiency and that sperm PLCζ analysis may benefit the widermale population and not onlymen with IcsI failure.

关键词： conventional IVF gene variants PLCζ polyspermy

Microstructure and Magnetization Investigations of Cu-Doping Effect on La_(2)CuO_(4+δ) Crystal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1997年第3期14卷 225-228页

作者： DONG Xiao-li ZHAO Bai-ru ZHAO zhong-xian LIU Wei ZHOU Lei XU Bo cheN Hong che guang-can NI Yong-ming YIN Bo LI Jing-wei ZHAO Li-hua XU Zhong-yu National Laboratory for Superconductivity Institute of Physics&Center for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100080 Department of Physics Hunan UniversityChangsha 410012

Measurement and characterization were carried out on Cu-doped and undoped La_(2)CuO_(4+δ) samples prepared under the same *** magnetization measurement on the Cu-doped La_(2)CuO_(4+δ) sample shows coexistence of long-range antiferromagnetic order and superconductivity.A stripe-like structure was observed at room temperature on the ab-plane of Cu-doped La_(2)CuO_(4+δ) sample by transmission electron *** for the undoped La_(2)CuO_(4+δ) sample no such behavior or structure feature was *** this letter,these phenomena were discussed in terms of phase separation.

关键词： conditions. separation. letter