圆柱形空间约束腔直径和深度对激光诱导硅等离子体光谱的影响

以硅靶作为烧蚀样品,研究了空气环境中空间约束的激光诱导击穿光谱.采用5×5组圆柱形约束腔来约束激光诱导的等离子体羽,直径分别为4、6、8、10、12mm,深度分别为2、4、6、8、10mm.激光脉冲的能量为70mJ.利用Si(I)390.55nm谱线分析了不同直径和深度的圆柱形空间约束腔对LIBS光谱强度的影响.结果表明空间约束下激光诱导硅产生的Si(I)390.55nm光谱强度明显高于无空间约束下的光谱强度.在当前的实验条件下,不同的约束腔的直径和深度对光谱辐射强度也有较大的影响,当圆柱形约束腔的直径和深度不同时,获得的光谱强度也是不同的,表明腔的尺寸对于光发射强度起很重要的作用.腔直径6mm和深度2mm的时候Si(I)390.55nm谱线强度出现最大值.空间约束的增强主要来自激光诱导的等离子体时伴随产生的冲击波,空间约束腔反弹冲击波并与等离子体进行相互作用,致使等离子体的温度和密度增加,最终提高等离子体的光辐射强度.     

基于TDLAS的层析成像技术TDLAT简

可调谐二极管吸收光谱技术（tunable diode laser absorption spectroscopy，TDLAS）已成为超声速燃烧的重要测量手段之一. 为提高其空间分辨能力，需发展基于TDLAS，结合层析成像术的二维断层成像术（tunablediode laser absorption tomography, TDLAT）. 设计了一套基于6 平行光束-旋转测量的新型TDLAT 系统，吸收波长为7 185.6 cm^-1 和7 444.3 cm^-1 双线，采用分时-直接吸收探测策略. 重建中，使用代数重建算法，先分别反演计算两吸收线的吸收率和吸收比分布，再获得温度和浓度分布. 利用该系统，在CH₄/Air 预混平面燃烧炉上开展初步验证试验. 结果表明，TDLAT 系统可以反演出温度和浓度分布特征，反演的温度分布结果与热电偶测量值吻合较好. 进一步改进该系统，可用于超燃直连台中，测量燃烧室出口气流的温度和组分浓度分布.     

Cu Segregation at ∑5 Symmetrical Grain Boundary in α-Fe： Atomic-Level Simulations

Cu-rich precipitation is regarded as one of the main issues causing embrittlement of ferritic steels. In the present work, the Cu segregation at ∑ 5 { 012} symmetrical grain boundary （GB） in BCC iron is investigated by combining Metropolis Monte Carlo and molecular statics approaches. The segregation driven energies of Cu clusters decrease with increasing the distance from GB and also depend on the duster size. The length scales associated with Cu segregation at GB are determined. All these results indicate that Cu atoms prefer to segregate at ∑5 GB, which may account for the embrittlement of ferritic steels. The present results provide important knowledge to understand the detailed mechanisms of Cu segregation at GB and also the possible effects on mechanical properties of α-Fe.     

光折变聚合物材料的研究进展

本文综述了光折变聚合物材料的发展历史和现状。概括出了这种新型光折变材料的发展思路 ,并汇总了各种类型材料的光折变特性参数。     

激光光谱技术对滑带土改性过程中阳离子交换的时间演化研究

目前岩土工程性能的测试多为破坏性试验,不能用于固土现场的在线监测。激光击穿光谱(laserinduced breakdown spectroscopy,简称LIBS)技术具有快速、实时在线等特点。利用自行搭建的一套LIBS检测系统对不同配比的离子土固化剂(ionic soil stabilizer,ISS)水溶液改性滑带土进行了时间演化研究,并通过与改性后土壤的塑性指数、粘聚力、压缩系数等工程性质的比对,发现在现有的三个配比(1∶100,1∶200,1∶300)中1∶200的ISS改性过程中阳离子交换速度最快,工程性能指标显示改性效果非常明显,这些工作为ISS应用于固土工程提供了实验依据,同时也为岩土工程性质的检测提供了一条新的思路。     

芳基四硫富瓦烯与碘电荷转移复合物的合成及其晶体结构

采用缓慢挥发溶剂的方法合成了硫原子桥联芳基取代四硫富瓦烯（Ar-S-TTF）与碘的3种电荷转移复合物（1^+·）（I₃）·I₂、（2^+·）（I₅）·I₂和（3²⁺）（I₃）₂,采用单晶X射线衍射、紫外可见光谱、循环伏安对其进行了表征。复合物（1^+·）（I₃）·I₂为C2/c空间群,1^+·呈椅式构型。化合物1与碘之间在溶液中和复合物中电荷转移一致。复合物（2^+·）（I₅）·I₂为P1空间群,2^+·呈椅式构型。复合物（3²⁺）（I₃）₂为Pbca空间群,3²⁺呈独特的平面构型。化合物2和3与碘之间在溶液中和复合物中呈现不同的电荷转移。复合物中聚碘阴离子呈现不同的堆积结构：由I₃^-或I₅^-/I₂组成的一维链状和I₃^-/I₂组成的二维网格状。     

利用高压水射流技术制备天然橡胶复合材料

首先利用超声空化作用将炭黑团聚体破碎、切割、分散在水中制得炭黑悬浮液,然后在高速射流场中,炭黑悬浮液被高速射流卷吸到天然胶乳中,在射流边界,由于二者存在极大的速度差,而形成一个湍流混合层,炭黑在湍流拉伸、剪切作用下微观分散到天然胶乳中.结果表明,与传统干法工艺相比,射流工艺可以使炭黑更均匀的分散到天然橡胶基体中.Payne效应结果表明射流工艺减弱了炭黑与炭黑之间的相互作用,增强了炭黑与橡胶之间的相互作用.同时射流工艺制备的复合材料硫化时间变短,硫化程度增加,硫化胶的撕裂强度提高了78%,回弹性提高了20%,DIN磨耗减小了33%.动态力学性能结果表明,射流工艺制备的复合材料在60℃左右具有更低的损耗因子.     

Investigation on the Percutaneous Enhancing Permeation Mechanism of Azone for Ketoprofen Based on the Intermolecular Hydrogen-bonding Interaction

The permeation enhancing activity of Azone for ketoprofen through excised cavia skins was investigated using Franz diffusion cell. The possible hydrogen-bonded complexes formed between ketoprofen and the model molecule of Azone as azacyclopentane-2-one were fully optimized at the B3LYP/6-311++G** level. The intermolecular hydrogen-bonding interactions were calculated using the B3LYP/6-311++G**, B3LYP/6-311++G(2df, 2p), MP2(full)/6-311++G** and MP2(full)/6-311++G(2df, 2p) methods, respectively. The results show that the steady-state permeation rate of ketoprofen through excised cavia skins enhances over 9 times in the solvent with 2% Azone as compared with the solvent without Azone. The stable O–H···O=C and N–H···O=C hydrogen-bonded complexes could exist between azacyclopentane and ketoprofen. The hydrogen-bonding interaction energy follows the order of(a) (b) (c) (d) (g)(e) (h) (f). The formation of the complexes leads to the change of the conformation and molecular polarity of ketoprofen, and thus causes a better percutaneous permeation for the drug. The analyses of AIM(atom in molecule) and shift of electron density were used to further reveal the nature of the enhancing permeation activity of Azone for ketoprofen. The investigations of the temperature and solvent effects confirm that ketoprofen might enter into the skin by means of the Azone complex.     

Long-distance quantum state transfer through cavity-assisted interaction

We propose a scheme for long-distance quantum state transfer between different atoms based on cavity-assisted interactions. In our scheme, a coherent optical pulse sequentially interacts with two distant atoms trapped in separated cavities. Through the measurement of the state of the first atom and the homodyne detection of the final output coherent light, the quantum state can be transferred into the second atom with a success probability of unity and a fidelity of unity. In addition, our scheme neither requires the high-Q cavity working in the strong coupling regime nor employs the single-photon quantum channel, which greatly relaxes the experimental requirements.     

Determination of breakdown voltage of In_(0.53)Ga_(0.47)As/InP single photon avalanche diodes

We examine the saturation of relative current gain of In0.53 Ga0.47As/InP single photon avalanche diodes(SPADs) operated in Geiger mode.The punch-through voltage and breakdown voltage of the SPADs can be measured using a simple and accurate method.The analysis method is temperature-independent and can be applied to most SPADs.