PAN基活性炭纤维的氮吸附研究

用相同原料不同活化方法制备聚丙烯腈基活性炭纤维,并对其进行了氮吸附研究.结 果表明,由不同活化方法所制备的活性炭纤维的孔结构存在较大差异,并对随着活化程度的 改变其孔结构的发展进行了研究.结果表明,通过简单的改变活化方法即可以制得不同孔隙占 主导地位的炭质吸附剂;也揭示出,不同的活化方法其活化机理有所差别.     

介孔分子筛SBA-15的研究进展

介孔分子筛SBA-15具有独特的物理化学性质和广阔的应用前景,成为众多研究领域的一个研究热点.本文结合我们自己的工作和国内外相关研究,较全面地介绍了近年来SBA-15的研究状况,并展望了今后的发展方向和应用前景.     

Electric Field Analysis of Space Charge Injection from a Conductive Nano-Filler Electrode

A simulation on the electric field distribution near the electrode is proposed to explain the reason for using nanosized carbon black mixed with ethylene vinyl acetate, as the electrode could lead to more charge injection into the polymer than using a deposited metal electrode. The electrode is simplified to a layer of conductive semi-spheres with fixed size and constant electric potential. By using the finite element method, it is found that both the size of the semi-spheres and the distance between adjacent semi-spheres could dramatically influence the electric field near the surface of the spheres; these are considered to be the two decisive factors for the charge injecting rate at electrodes of various materials.     

30J能量驱动类镍银X光激光的理论研究

 在1.2×10¹³W·cm^－2低功率密度下，对基频激光预主短脉冲驱动类镍银X光激光机理进行了数值模拟和理论分析。证实了在靶长23 mm范围内X光激光都能获得有效放大，取得了和实验相符合的结果。考虑了单柱面镜线聚焦沿靶长度方向功率密度的非均匀性对X光激光放大的影响，采用弯曲靶能有效克服折射以及单柱面镜线聚焦功率密度非均匀带来的不利影响。理论模拟给出的类镍银X光激光的出光下限泵浦功率密度也与实验符合得很好。理论模拟还表明，采用1%左右的预脉冲强度并对预主脉冲时间间隔进行优化，X光激光的输出能量和能量转换效率将获得大幅度提高。     

红外焦平面技术的重要进展—单片式SiGe红外焦平面阵列的物理基础和关键技

由ＳｉＧｅ合金与Ｓｉ构成的应变层异质结构、量子阱是８０年代中期发展起来的一种新型半导体材料。本文着重讨论了单片式ＳｉＧｅ红外焦平面阵列的物理基础、高质量ＳｉＧｅ材料的制备以及低温ＳｉＧｅ器件研制中的几个关键技术。     

马烯雌酮及其衍生物的高效合成

马烯雌酮及其衍生物是结合雌激素药物的重要组成成分,主要从孕马尿中提取获得.由于存在不稳定的非共轭双键,化学合成非常困难.以商品化的19-羟基-4-烯-3,17-二酮雄甾为原料,retro-aldol芳构化反应为关键步骤,分别以32%,37%和25%的收率合成了马烯雌酮(7)、17β-二氢马烯雌酮(8)和17α-二氢马烯雌酮(9).     

Measuring Loschmidt echo via Floquet engineering in superconducting circuits

The Loschmidt echo is a useful diagnostic for the perfection of quantum time-reversal process and the sensitivity of quantum evolution to small perturbations. The main challenge for measuring the Loschmidt echo is the time reversal of a quantum evolution. In this work, we demonstrate the measurement of the Loschmidt echo in a superconducting 10-qubit system using Floquet engineering and discuss the imperfection of an initial Bell-state recovery arising from the next-nearest-neighbor (NNN) coupling present in the qubit device. Our results show that the Loschmidt echo is very sensitive to small perturbations during quantum-state evolution, in contrast to the quantities like qubit population that is often considered in the time-reversal experiment. These properties may be employed for the investigation of multiqubit system concerning many-body decoherence and entanglement, etc., especially when devices with reduced or vanishing NNN coupling are used.     

Construction of Two Coordination Polymers Based on Two New 5-Substitued Tetrazole-based Ligands: Structures and Luminescent Properties

Two new coordination polymers(CPs) based on two new tetrazole-based ligands, namely, [Cu(TPP)]n(HTTP = 4-(3-(2 H-tetrazol-5-yl)phenyl)pyridine, 1) and {[Cd_2(TBCA)_2(H_2O)_2]·-H_2O}n(H_2TBCA = 3?-(2 H-tetrazol-5-yl)biphenyl-4-carboxylic acid, 2), were synthesized via solvothermal reactions. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a(3,6)-connected rtl network topology based on binuclear secondary building units(SBUs). Compound 2 presents a 2D framework composed of 1D SUBs formed by both carboxyl and tetrazole groups. The 2D network is linked into a 3D framework via various hydrogen bonds. They represent two examples of CPs construct from rigid 5-substitued tetrazole-based ligands with relatively longer spacer. The thermal stabilities and luminescent properties of compounds 1 and 2 were also explored.     

关于L_p球的几个新不等式和性质(英文)

本文研究了L_p球的相关问题.利用对偶混合体积、球面Radon变换和Fourier变换的方法,获得了关于L_p球的几个新不等式和性质,其中一个不等式与著名的最大切片猜想有关.