通过固相交换法制备的（Li,NH4）-LSX分子筛骨架中Li+的分布

采用固相交换法对NH4-LSX分子筛进行Li+交换,详细考察了交换温度和交换时间以及LiCl·H2O与分子筛的摩尔比对其结构与性能的影响,并得到最佳交换条件,由此制备出不同Li+交换度的锂型低硅铝比X型分子筛((Li,NH4)-LSX),采用XRD、FT-IR、SEM、TG和NMR等手段对其进行表征,探讨了不同交换度的(Li,NH4)-LSX分子筛骨架中Li+的分布数量和结构变化。     

基体碳材料对锂硫电池性能影响的研究

采用乙炔黑、土状石墨、Cabot Vulcan XC-72炭黑、Cabot Bp2000超级导电炭黑作为硫载体制备了一系列含硫复合材料。通过X射线粉末晶体衍射(XRD)、扫描电子显微镜(SEM)、比表面积分析(BET)等分析测试手段对材料的物理性能进行表征,利用电池测试系统对材料的电化学性能进行了测试。结果表明基体材料表面结构、孔径分布及比表面积等因素都对复合材料的电化学性能造成影响,综合性能最好的基体材料为BP2000超级导电炭黑,其初始放电比容量高达1385.1mAh/g,在室温下经过30次循环之后电池放电比容量仍保持在1080.2mAh/g,容量保持率高达78%。     

含Li的AI—Zn—Mg-Cu合金的研究进展

要对含Li的A1-Zn-Mg-Cu合金的研究进展进行了回顾与总结。含Li量大于1．8％的A1-Zn-Mg-Cu合金基体中主要沉淀相是δ＇相、S相和T’相，塑性和韧性较差。含Li量不大于1．0％的AI-Zn-Mg-Cu合金基体上析出η’，相或T’相，二级时效或多级时效则可使其达到较高的硬度。最后，指出含U的A1-Zn-Mg-Cu合金目前存在的问题，并提出了进一步研究的方向。     

Room Temperature Ferromagnetism in Dual Doped (Mn 2+ , Ni 2+ ) ZnO Codoped with Li 1+ Prepared Using EDTASintered at Low Temperature

Nanopowders of Znl_x_y_zMnxNiyLizO [（x = 0.04, y = 0, z = 0）, （x = 0.04, y = 0.03, z = 0） and （x = 0.04, y = 0.03, z = 0.03）] have been synthesized by sol-gel precursor route using ethylene diamine tetraacetic acid （EDTA） as a metal chelating agent. X-ray diffraction analysis confirms the formation of wurtzite hexagonal structure for all the three compositions. Mn2＋ doped ZnO exhibits room temperature ferromagnetism （RTFM）, and it is found that further Ni2＋ doping has decreased Ms because of limit of solid solubility of transition metal in ZnO. But codoping of monovalent Li1＋, further increases the ferromagnetism （FM） value, due to introduction of free carriers compared to the dual doped samples. Photoluminescence （PL） spectra of the system, exhibit near band edge （NBE） emission peak at --464 nm due to the electron transition from interstitials to the valence band. Recombination of conduction electron with hole trapped at oxygen vacancy, leads to prominent defect emission peaks at --482 nm and 532 nm. The evidence of the formation of metaI-EDTA complexes are found from the Fourier transform infrared spectra at 2800-3800 cm-1 with shifting, splitting of the peak and also drastic variations in the intensity.     

Optical conductivity of a superconductor withdx2?y2 symmetry

Using a simplified Eliashberg formulation in which we keep only that part of the susceptibility which is separable and of symmetry in the pairing channel and keep the isotropic part in the renormalization channel, we have calculated the ac conductivity in the superconducting state. At zero temperature, in the clean limit, we find a finite amount of absorption at any frequency, however small, although it is substantially reduced over its normal-state value. Besides this boson-assisted absorption, when impurities are added a new channel is opened up in which momentum is given up to the impurity system and absorption proceeds directly through the creation of a hole-particle pair. Born and unitary impurity scattering are considered.This research was supported in part by the Canadian Institute for Advanced Research (CIASR), by the Ontario Centre for Materials Research (OCMR), and by the Natural Sciences and Engineering Research Council o f Canada (NSERC).     

Flexible carbon nanotube--Cu2O hybrid electrodes for li-ion batteries

This study demonstrates the formation of a flexible and free-standing carbon nanotube-copper oxide-poly(vinylidene fluoride) (CNT-Cu(2) O-PVDF) nanocomposite and its application as an electrode-separator material for Li-ion batteries. Binder-free hybrid electrodes are obtained by conformally coating CNTs with Cu(2) O via electrodeposition and then embedding the resulting architecture into a porous poly(vinylidene fluoride-hexafluoropropylene) PVDF-HFP-SiO(2) polymer electrolyte membrane. The synergistic presence of high-capacity transition metal oxides and conductive CNTs results in twice the reversible areal capacity of 2.3 mAh cm(-2) as compared to 1.2 mAh cm(-2) for pure CNTs.     

ZnS:Li_2O 薄膜的电致发光特性

本文报道了新型较高亮度的ZnS:Li2O蓝色薄膜电致发光,烧结了新型的蓝色发光材料ZnS:Li2O,用电子束蒸发制备出SiO2夹层结构的ZnS,Li2O蓝色电致发光器件,通过吸收光谱,电致发光光谱,激光光电压与发光强度的关系等研究了ZnS:Li2O薄膜发光特性,认为ZnS:Li2O薄膜电致发光可能是由Zn填隙和氧替硫引起的。氧替位能抑制通过硫空位产生的无辐射跃迁使蓝色发光增强。     

Neutron detection by superconducting tunnel junctions on a Li2B4O7 single-crystal absorber

We succeeded in detecting neutrons using superconducting tunnel junctions (STJs) fabricated on a single crystal of Li₂B₄O₇. Neutrons are captured in the crystal by the nuclear reactions ⁶Li+n→T+alpha+4.78 MeV and ¹⁰B+n→⁷Li+alpha+2.3 MeV, which excite a large number of phonons in the substrate. The phonons propagate in the absorber and are measured by the STJs. We selected a single crystal of Li₂B₄O₇ as the absorber material because of properties such as the large neutron cross-section of ⁶Li and ¹⁰B, low γ-ray sensitivity, short particle range in the substrate, and fast phonon velocity. Series-connected or multiple STJs on the crystal would enable two-dimensional neutron imaging with high detection efficiency, low γ-ray background, and a high spatial resolution of a few microns. In this paper, we demonstrate neutron detection by STJs and report the basic characteristics of the fabricated STJs, including their X-ray response and neutron detection. The correlation in pulse heights between two junctions located 1.3 mm apart clearly indicates the possibility of neutron imaging.     

热连轧GH4169合金的点阵常数与蠕变性能

通过对热连轧GH4169合金进行热处理、组织形貌观察、点阵常数测定及蠕变性能测试,研究热连轧GH4169合金的点阵常数与蠕变行为。结果表明:热连轧GH4169合金主要由γ基体、γ′和γ″相组成,经标准热处理后,合金中部分粒状γ′相重溶,且又在基体中析出扁平状γ″相;经X射线衍射分析表明,与热连轧合金相比,THR-ST-GH4169合金中γ基体、γ′和γ″相的点阵常数较小,但各相之间具有较大的晶格错配度,可有效阻碍位错运动,是合金具有较高蠕变抗力和较长蠕变寿命的重要因素之一;在蠕变期间,热连轧合金的主要变形机制为位错的双取向滑移,而在THR-ST-GH4169合金中,可形成形变孪晶和发生位错滑移。