Superposition of Coherent States in a Mesoscopic Josephson Junction with Dissipation

A mesoscopic Josephson junction with dissipation is considered. Usually the dissipation in the system is described as a consequence of its coupling to a reservoir. By solving the master equation we show that the state of the junction can evolve in a quantum superposition of two coherent states even when the dissipation is present.``     

Optical Properties of a New Two-photon Absorption Dye DEASPI

The two-photon absorption (TPA), TPA-induced frequency up-conversion emission, and two-photon pumped (TPP) frequency up-conversion lasing properties of a new synthesized dye Trans-4-［p-(N,N-diethylamino)styryl］-N-methylpyridinium iodide (DEASPI) were experimentally studied. This new dye has a moderate TPA cross-section of σ2=6.9×10-48 cm4*s/photon at 1064 nm, but exhibits a high lasing efficiency. The overall superradiant lasing conversion efficiency is as high as 10.7% at the pump energy of 2.14 mJ.     

Effect of Vacuum on the Laser-Induced Damage of Anti-Reflection Coatings

In the comparison of damage modifications, absorption measurement and energy dispersive x-ray analysis, the effect of vacuum on the laser-induced damage of anti-reflection coatings is analyzed. It is found that vacuum decreases the laser-induced damage threshold of the films. The low laser-induced damage threshold in vacuum environments as opposed to air environments is attributed to water absorption and the formation of the O/Si, O/Zr sub-stoichiometry in the course of laser irradiation.     

大口径石英基底衍射透镜的高精度制备方法

针对传统接触式曝光过程中掩模版因自身重力产生形变从而引入不可忽视的线宽误差和位置误差的问题,提出了一种大口径石英基底衍射透镜的高精度制备方法.采用背面具有真空道的高平面度、高强度金属校正工装吸附在掩模版上,利用掩模版上下表面的压强差使其与工装高度贴合,确保掩模版的高平面度.待石英基底所有区域均与掩模版结构面紧密贴合后取下工装.完成接触式曝光和显影后,采用反应离子刻蚀技术对大口径石英基底进行刻蚀,最终得到高精度微纳米结构.经有限元分析,使用该校正工装后,掩模版的形变量由28.85μm减小为0.88μm.实验结果表明,采用该方法制备的口径430mm两台阶石英基底菲涅尔衍射透镜波像差优于1/25λ,平均衍射效率为38.24%,达到理论值的94.35%,具有良好的聚焦和光学成像效果.     

An X-ray imaging device based on a GEM detector with delay-line readout

An X-ray imaging device based on a triple-GEM (Gas Electron Multiplier) detector, a fast delay-line circuit with 700 MHz cut-off frequency and two dimensional readout strips with 150 μm width on the top and 250 μm width on the bottom, is designed and tested. The localization information is derived from the propagation time of the induced signals on the readout strips. This device has a good spatial resolution of 150 μm and works stably at an intensity of 105 Hz/mm2 with 8 keV X-rays.     

基于基金项目的“一带一路”研究格局与态势分析

以国家和有关部委的资助项目库为数据来源,检索2014-2016年“一带一路”的相关基金立项,运用文献计量和空间分析的方法从项目的负责人、科研单位、所属地域、学科、研究内容等多个角度进行解析,旨在揭示 “一带一路”研究的格局与态势.结果表明：（1）“一带一路”相关基金立项数目总体呈逐年上升趋势,增速平缓,国家社科基金主体地位明显.（2）项目所属单位、省份在空间上呈现集中分布趋势,体现了一定的区位优势、空间关联与地理邻近效应.（3）单个负责人的立项数目差异不大,分布较为平均.（4）“一带一路”、丝绸之路经济带、21世纪海上丝绸之路为目前学者主要的研究对象和议题.（5）各类基金高频词汇基本保持同步,五类基金研究的热门领域大体趋于一致,包括经济学、国际问题研究、民族问题研究和交叉学科研究等.最后,从研究数据、时间、空间及学科与合作前景上,对未来的研究趋势做了总结和展望.     

不同直径碳纳米管的抗电化学氧化性

本文比较了由化学气相沉积法制备的不同直径(在100 nm以内)的多壁碳纳米管(CNT)的抗电化学氧化性.将CNT电极于1.2 V(vs.RHE)下电氧化120 h,记录氧化电流~时间变化曲线;X射线光电子能谱(XPS)分析氧化前后CNT的表面化学组成.结果表明,随着CNT直径的减小,其氧化电流降低,但其中以为10~20 nm的CNT电极氧化电流最小,表面氧的增量也最小,即被氧化的程度最低,抗电化学氧化性最强.根据不同直径CNT的缺陷位、不定型碳的丰度和碳原子的应力能,分析了其抗电化学氧化性差异的原因.     

以醚胺为模板剂合成含二价金属杂原子的开放骨架磷酸铝化合物M(Ⅱ)-CJ50

在水热体系中, 以2,2'-(乙烯二氧)双(乙胺)为模板剂, 合成了3种含二价金属杂原子的开放骨架磷酸铝化合物M(Ⅱ)-CJ50(|C₆H₁₇N₂O₂| [MAl₃P₄O₁₆], 其中M=Mg, Mn和Fe). 单晶及粉末X射线衍射分析表明, 这3种化合物与以咪唑为模板剂合成的含三价金属杂原子的M(Ⅲ)-CJ50具有相似的骨架拓扑结构. 二者的区别在于: 由于使用了还原性较强的醚胺作模板剂, M(Ⅱ)-CJ50结构中的金属杂原子具有比M(Ⅲ)-CJ50更低的氧化态; M(Ⅱ)-CJ50中的金属杂原子与1个醚胺模板剂分子中的2个醚氧原子形成双齿配位, 而M(Ⅲ)-CJ50中的金属杂原子则与2个咪唑模板剂分别形成单齿配位. 此外, 磁性测试结果表明, 由于金属杂原子的氧化态以及配体模板剂分子的差异, 导致M(Ⅱ)-CJ50中的过渡金属杂原子处于电子高自旋态, 而M(Ⅲ)-CJ50中的杂原子则处于低自旋态.     

Synthesis and Structure of K_3Na_3〔MnMo_9O_(32)〕·6H_2O

1INTRODUCTIONHeteroPOlymolybdatesareknownwithaverywiderangeofmetalionsithetypeandstabilityoftheclustersshowdependenceonboththeheteroatomandPH"'.TheknownheteroPOlymolybdateswhichincludemanganese(1)ormanganese(IV)havebeenreported.Afewofhetercrg-molybdateanionswiththemanganese(IIV)andnickel(IV)formsarecharacterizedandisostructural[2).Thesehigheroxidationstatespecieshavebeenpreparedpreviouslybyoxidationoflower--valentspecieswithPOwerfuloxidant,suchasPeroxydisulfateorPeroxymonosulfurica…     

聚乙烯载体催化剂的制备与表征

不同目数的聚乙烯粉末通过辐射方法接枝了4-乙烯基吡啶官能团.经甲基铝氧烷(MAO)预处理后负载了茂金属催化剂Cp₂ZrCl₂.光电子能谱和红外光谱结果表明催化剂通过MAO的作用负载在聚乙烯接枝4-乙烯基吡啶聚合物上.4-乙烯基吡啶的接枝含量、催化剂的负载率以及载体催化剂对乙烯单体的活性均随着聚乙烯粉末的颗粒减小而增大.