Effect of Pr—doping on band structures of YBa2Cu3Oy superconductors

ＥｆｆｅｃｔｏｆＰｒ－ｄｏｐｉｎｇｏｎｂａｎｄｓｔｒｕｃｔｕｒｅｓｏｆＹＢａ＿２Ｃｕ＿３Ｏ＿ｙｓｕｐｅｒｃｏｎｄｕｃｔｏｒｓＬｉＭｉｎｇ；ＦｕＷｅｎｔａｏ（ｓｃｈｏｏｌｏｆＣｈｅｍｉｓｔｒｙａｎｄＣｈｅｍｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｓｏｎｔｈｗｅ...     

Band-structure study on YBa_2Cu_(3-x)Co_xO_y

ＢａｎｄｓｔｒｕｃｔｕｒｅｓｔｕｄｙｏｎＹＢａ２Ｃｕ３－ｘＣｏｘＯｙＨｅＹｏｕｑｉｕ，ＬｉＭｉｎｇＳｃｈｏｌｏｆＣｈｅｍｉｓｔｒｙａｎｄＣｈｅｍｉｃａｌＥｎｇｉｎｅｒｉｎｇ，ＳｏｕｔｈｗｅｓｔＣｈｉｎａＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｃｈｏｎｇｑ...     

Optical fiber Bragg grating sensors in smart structures

ＯｐｔｉｃａｌｆｉｂｅｒＢｒａｇｇｇｒａｔｉｎｇｓｅｎｓｏｒｓｉｎｓｍａｒｔｓｔｒｕｃｔｕｒｅｓＷｅｉｃｈｏｎｇＤｕ１，２，ＷＪｉｎ２，ＳＨＬｉｕ１（１ＨｏｎｇＫｏｎｇＰｏｌｙｔｅｃｈｎｉｃＵｎｉｖ．２ＳｏｕｔｈＣｈｉｎａＮｏｒｍａｌＵｎｉｖ．）Ｏｐ...     

SURFACE MODE ABSORPTION IN ZnOCOATED Zn PARTICLES

ＳＵＲＦＡＣＥＭＯＤＥＡＢＳＯＲＰＴＩＯＮＩＮＺｎＯＣＯＡＴＥＤＺｎＰＡＲＴＩＣＬＥＳ￥ＸｕＪａｉｎｆｅｎｇ；ＤｕＹｏｕｗｅｉ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓａｎｄＬａｂｏｒａｔｏｒｙｏｆＳｏｌｉｄＳｔａｔｅＭｉｃｒｏｓｔｒｕｃｔｕｒｅｓ，Ｎ...     

HARMONIC AC SUSCEPTIBILITY FOR TEXTURED YBa_2Cu_3O_7

ＨＡＲＭＯＮＩＣＡＣＳＵＳＣＥＰＴＩＢＩＬＩＴＹＦＯＲＴＥＸＴＵＲＥＤＹＢａ２Ｃｕ３Ｏ７ＧｅＹｏｎｇ１）ＤｉｎｇＳｈｉＹｉｎｇ２）（１）ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ,ＮａｔｉｏｎａｌＬａｂｏｆＳｏｌｉｄＳｔａｔｅＭｉｃｒｏｓｔｒｕｃｔｕｒ...     

THE JET-DRIVEN BOW SHOCK IN OUTFLOWS

Ｒｅｃｅｎｔｈｉｇｈｒｅｓｏｌｕｔｉｏｎｏｂｓｅｒｖａｔｉｏｎｓｓｈｏｗｔｈｅｈｉｇｈｃｏｌｌｉｍａｔｅｄｂｉｐｏｌａｒｍｏｌｅｃｕｌａｒｏｕｔｆｌｏｗｓｆｒｏｍｙｏｕｎｇｓｔｅｌｌａｒｏｂｊｅｃｔｓ,ｓｕｃｈａｓＮＧＣ２２６４ＧａｎｄＮＧＣ２０２４．Ｅｘｉｓｔｉｎｇｍｏｄｅｌｓｃａｎｎｏｔｙｅｔｇｉｖｅｃｏｍｐｌｅｔｅｉｎｔｅｒｐｒｅｔａｔｉｏｎｓｏｆｔｈｅｓｔｒｕｃｔｕｒｅａｎｄｐｒｏｐｅｒｔｉｅｓｏｆｔｈｅｏｂｓｅｒｖｅｄｆｌｏｗ．Ｈｅｒｅ,ｗｅｐｒｏｐｏｓｅａｊｅｔｄｒｉｖｅｎｂｏｗ…     

Structures of Turbulent Flows in Near-wall Region

ＳｔｒｕｃｔｕｒｅｓｏｆＴｕｒｂｕｌｅｎｔＦｌｏｗｓｉｎＮｅａｒ┐ｗａｌＲｅｇｉｏｎＺｈａｎｇＺｈａｏｓｈｕｎ（张兆顺），ＸｕＣｈｕｎｘｉａｏ（许春晓）ＤｅｐａｒｔｍｅｎｔｏｆＥｎｇｉｎｅｅｒｉｎｇＭｅｃｈａｎｉｃｓ，ＴｓｉｎｇｈｕａＵｎｉｖｅｒｓｉ...     

Brittle-plastic Theory and Identification of Material Properties for Elastoplastic Structure

Ｂｒｉｔｌｅ┐ｐｌａｓｔｉｃＴｈｅｏｒｙａｎｄＩｄｅｎｔｉｆｉｃａｔｉｏｎｏｆＭａｔｅｒｉａｌＰｒｏｐｅｒｔｉｅｓｆｏｒＥｌａｓｔｏｐｌａｓｔｉｃＳｔｒｕｃｔｕｒｅＸｕＢｉｎｇｙｅ（徐秉业），ＣｅｎＺｈａｎｇｚｈｉ（岑章志），ＳｈｅｎＸｉｎｐｕ（沈新...     

Tunneling of Electrons in Multibarrier Heterostructures under Crossed Electric and Magnetic Fields

ＴｕｎｎｅｌｉｎｇｏｆＥｌｅｃｔｒｏｎｓｉｎＭｕｌｔｉｂａｒｒｉｅｒＨｅｔｅｒｏｓｔｒｕｃｔｕｒｅｓｕｎｄｅｒＣｒｏｓｅｄＥｌｅｃｔｒｉｃａｎｄＭａｇｎｅｔｉｃＦｉｅｌｄｓ＊ＧｕｏＹｏｎｇ（郭永），ＧｕＢｉｎｇｌｉｎ（顾秉林），ＺｈａｎｇＸｉａｎｇｄ...     

DISTRIBUTION OF VORTEX BARRIERS AT DIFFERENT TEMPERATURES FOR TL 2212 FILM

ＴｈｅｅｎｅｒｇｙｂａｒｒｉｅｒｏｆｖｏｒｔｅｘｍｏｔｉｏｎＵｉｓｖｅｒｙｉｍｐｏｒｔａｎｔｉｎｖｏｒｔｅｘｄｙｎａｍｉｃｓ．Ｉｎｔｈｉｓｌｅｔｔｅｒ，ＷｅｒｅｐｏｒｔｓｕｃｈｂａｒｒｉｅｒｄｉｓｔｒｉｂｕｔｉｏｎｆｕｎｃｔｉｏｎＰ（Ｕ）ｄｅｔｅｒｍｉｎｅｄｂｙａｃｓｕｓｃｅｐｔｉｂｉｌｉｔｙ（ａｃｓ）ｔｅｃｈｎｉｑｕｅ．ＴｈｅｅｆｆｅｃｔｓｏｆｆｒｅｑｕｅｎｃｙａｎｄａｃａｍｐｌｉｔｕｄｅｏｎａｃｓｗｅｒｅｍｅａｓｕｒｅｄｆｏｒａｔｈｉｎｆｉｌｍＴｌ２Ｂａ２ＣａＣｕ２Ｏ８ｉｎａｄｃｍａｇｎｅ…     

Enhancing thermoelectric performance of Cu-modified Bi0.5Sb1.5Te3 by electroless plating and annealing

With the capacity of energy conversion from heat to electricity directly, thermoelectric materials have been considered as an alternative solution to global energy crisis. In this work, Cu modified Bi_(0.5)Sb_(1.5)Te_3(BST)composites are prepared by a facile electroless plating Cu method, spark plasma sintering, and annealing. The annealed 0.22 wt.%Cu/BST has an enhanced peak Figure of Merit(z T) of ~ 0.71 at 573 K with high average z T of0.65 in the wide temperature range between 300 and 573 K. Due to the significant increase of electrical conductivity and low lattice thermal conductivity, the annealed 0.22 wt.%Cu/BST shifts peak z T to high temperature, and shows 492% enhancement than that of pristine BST with z T of 0.12 at 573 K. Through detailed structural characterization of the annealed 0.22 wt.%Cu/BST, we found that Cu can dope into BST matrix and further form Cu2 Te nanoprecipitates, dislocations, and massive grain boundaries, leading to a low lattice thermal conductivity of 0.30 Wm-1 K-1 in the annealed 0.22 wt.%Cu/BST. Such enhanced peak z T in high-temperature and high average z T in the wide temperature range shows that the electroless plating Cu method and annealing can improve the thermoelectric performance of commercial BST and expand the applicability of Bi_2Te_3 thermoelectric materials in the power generations.     

铋系超导体晶格振动的X射线衍射研究

本讨论了利用变温X射线衍射方法在液氮至室温温区上研究了Bi1.6Pb0.4Sr2Ca2Cu3-xFexOy(x=0,0.08)铋系高温超导相晶格振动的动态行为。变温X射线的研究工作集中在（002）晶面上,它能反映与超导电性有密切关系的Bi-O层和Cu-O的晶格振动信息。在超导转变温度以上的120K附近温区上,（002）峰的衍射强度I（T）与晶格常数C（T）随温度变化的异常行为表明,在超导转变前（002）晶面出现了明显的晶格软化效应。     

Strain-induced metal-insulator phase coexistence in perovskite manganites

The coexistence of distinct metallic and insulating electronic phases within the same sample of a perovskite manganite, such as La(1-x-y)Pr(y)Ca(x)MnO3, presents researchers with a tool for tuning the electronic properties in materials. In particular, colossal magnetoresistance in these materials--the dramatic reduction of resistivity in a magnetic field--is closely related to the observed texture owing to nanometre- and micrometre-scale inhomogeneities. Despite accumulated data from various high-resolution probes, a theoretical understanding for the existence of such inhomogeneities has been lacking. Mechanisms invoked so far, usually based on electronic mechanisms and chemical disorder, have been inadequate to describe the multiscale, multiphase coexistence within a unified picture. Moreover, lattice distortions and long-range strains are known to be important in the manganites. Here we show that the texturing can be due to the intrinsic complexity of a system with strong coupling between the electronic and elastic degrees of freedom. This leads to local energetically favourable configurations and provides a natural mechanism for the self-organized inhomogeneities over both nanometre and micrometre scales. The framework provides a physical understanding of various experimental results and a basis for engineering nanoscale patterns of metallic and insulating phases.     

Bi2（Sr,Ca）3Cu2Oy超导体的EXAFS研究

利用扩展Ｘ射线吸收精细结构（ＥＸＡＦＳ），研究了Ｂｉ２（Ｓｒ，Ｃａ）２Ｃｕ２Ｏｙ超导体中Ｃｕ原子与Ｂｉ原子的局域结构．结果表明：Ｃｕ原子第一配位层是五配位的氧原子，第二配位层是四配位的Ｃａ原子和一配位的Ｃｕ原子，但不含Ｓｒ原子的结构信息，这是Ｓｒ－Ｏ层与Ｃｕ－Ｏ层层间距较大所致；同时测定Ｂｉ原子第一配住层含有２．３个氧原子，用非公度调制结构模型解释了Ｂｉ原子的配位状况．     

宽叶吊石苣苔的胚胎学研究及其系统学意义

观察和记录了较完整的宽叶吊石苣苔 ( Lysionotus pauciflorusvar.latifolius)胚胎学发育过程 ,其花药有四个小孢子囊 ,绒毡层属分泌型 ,花药壁的发育属双子叶型 ,小孢子母细胞胞质分裂为同时型 ,具四面体型的四分体 ,花粉二细胞型 ;孢原细胞直接发育为大孢子母细胞 ,四分体直列式 ,倒生胚珠 ,单珠被 ,薄珠心 ,蓼型胚囊 ;珠孔受精 ,细胞型胚乳 ,具细长的 2核单胞合点端吸器和 2个单核细胞珠孔端吸器 ;胚胎发育为柳叶菜型 .分析表明 ,苦苣苔科胚胎学特征与玄参科 ( Scrophulariaceae)、列当科 ( Orobanchaceae)和爵床科 ( Acanthaceae)较为相似 ,反映了系统学上的相近性     

Phase transitions in the incoherent lattice fluctuations in YBa2Cu3O(7-delta)

The growing body of experimental evidence for the existence of complex textures of charges and spins in the high-temperature superconductors has drawn attention to the so-called 'stripe-phase' models as a possible basis for the mechanism of superconductivity in these materials. Such observations have until now been restricted to systems where the texture dynamics are slow or suppressed altogether, and do not include the important case of YBa2Cu3O(7-delta). It seems likely that the dynamic behaviour of stripes, which has been suggested to undergo several phase transitions as a function of temperature, should also be reflected in the lattice properties of the host materials, and this forms the motivation for our present experiments. Specifically, we use MeV helium ion channelling, an ultrafast real-space probe of atomic displacements (with sub-picometre resolution), to probe incoherent lattice fluctuations in YBa2Cu3O(7-delta) as a function of temperature and oxygen doping. We detect lattice fluctuations that are larger than the expected thermal vibration component, and which show anomalies characteristic of the phase transitions anticipated for a dynamic stripe phase. Comparison of our lattice results with single-particle-tunnelling and photoemission data highlights the importance of spin-charge separation phenomena in the copper oxide superconductors.     

碳化钨晶格中的氧原子及其对催化活性的影响

用XPS、XRD、EXAFS及EHMO量子计算等多种分析方法确证了低温合成的碳化钨晶格中嵌入了氧原子.碳化钨对烷烃转化反应及CO加氢反应都有活性。晶格氧使碳化钨的比活性略有下降.     

无序和有序GaInP2的光致发光谱

对无序和有序ＧａＩｎＰ２样品分别作了变温和变激发功率密度光致发光谱的测量．无序样品表现为与激发功率密度无关的单谱峰结构，在不同温度区有不同的激活能．有序样品则表现为双峰结构，其中高能端发光峰强度随温度升高先增强而后热猝灭．根据样品有序度及取向超晶格模型解释了实验现象     

EXAFS研究合成甲醇催化剂Cu/ZnO/AL_2O_3的制备条件

用EXAFS研究了不同制备条件对合成甲醇催化剂Cu／ZnO／Al2O3结构的影响,研究表明选择较温和的还原气氛和还原温度有利于制备高分散的Cu催化剂,在还原前较小的焙烧温度有利于制备较小颗粒的ZnO粒子,此研究表明Cu0是催化剂的主要活性组分．