激光脉冲系统时域响应的偏离度参数

从理论上定义了基于高斯脉冲成分分析的激光脉冲时域响应的偏离度参数,并且通过实验验证了该定义的有效性.利用高速光电探测系统测量入射和出射的微秒量级激光脉冲的实际能量分布,在3%的容差范围内对能量分布进行高斯脉冲分量拟合,通过对比各独立高斯成分的归一化强度经系统后的理想值与真实值,计算得到偏离度.在该定义下,通过分析各高斯分量的权重演化以及新分量的成因,不仅可以研究光场与系统相互作用的物理机制,而且为系统的优化设计提供帮助.     

Hierarchically Structured Composite Fibers for Real Nanoscale Manipulation of Carbon Nanotubes

Carbon nanotube (CNT)-reinforced polymer fibers have broad applications in electrical, thermal, optical, and smart applications. The key for mechanically robust fibers is the precise microstructural control of these CNTs, including their location, dispersion, and orientation. A new methodology is presented here that combines dry-jet-wet spinning and forced assembly for scalable fabrication of fiber composites, consisting of alternating layers of polyacrylonitrile (PAN) and CNT/PAN. The thickness of each layer is controlled during the multiplication process, with resolutions down to the nanometer scale. The introduction of alternating layers facilitates the quality of CNT dispersion due to nanoscale confinement, and at the same time, enhances their orientation due to shear stress generated at each layer interface. In a demonstration example, with 0.5 wt% CNTs loading and the inclusion of 170 nm thick layers, a composite fiber shows a significant mechanical enhancement, namely, a 46.4% increase in modulus and a 39.5% increase in strength compared to a pure PAN fiber. Beyond mechanical reinforcement, the presented fabrication method is expected to have enormous potential for scalable fabrication of polymer nanocomposites with complex structural features for versatile applications.     

Thermodynamic Properties and Molecular Packing Explain Performance and Processing Procedures of Three D18:NFA Organic Solar Cells

Organic solar cells (OSCs) based on D18:Y6 have recently exhibited a record power conversion efficiency of over 18%. The initial work is extended and the device performance of D18-based OSCs is compared with three non-fullerene acceptors, Y6, IT-4F, and IEICO-4Cl, and their molecular packing characteristics and miscibility are studied. The D18 polymer shows unusually strong chain extension and excellent backbone ordering in all films, which likely contributes to the excellent hole-transporting properties. Thermodynamic characterization indicates a room-temperature miscibility for D18:Y6 and D18:IT-4F near the percolation threshold. This corresponds to an ideal quench depth and explains the use of solvent vapor annealing rather than thermal annealing. In contrast, D18:IEICO-4Cl is a low-miscibility system with a deep quench depth during casting and poor morphology control and low performance. A failure of ternary blends with PC₇₁BM is likely due to the near-ideal miscibility of Y6 to begin with and indicates that strategies for developing successful ternary or quaternary solar cells are likely very different for D18 than for other high-performing donors. This work reveals several unique property–performance relations of D18-based photovoltaic devices and helps guide design or fabrication of yet higher efficiency OSCs.     

硫化铋@铁酸铜异质结的构筑及光触发抗菌性能研究

病原体细菌感染引起的相关感染在世界范围内严重威胁着人类的生命安全健康。为解决该问题,研究构筑了一种由硫化铋（Bi₂S₃）与铁酸铜（CuFe₂O₄）共筑形成的近红外光触发的异质结功能材料体系Bi₂S₃@CuFe₂O₄,其通过Bi₂S₃与CuFe₂O₄之间的静电吸附作用力相结合。使用近红外光成像仪记录了材料在不同的近红外光功率下的升温曲线,验证了材料的光热效应;以1,3-二苯基异苯并呋喃（DPBF）作为活性氧的捕获剂,验证了材料的光动力效应。结果表明,Bi₂S₃@CuFe₂O₄在近红外光的触发下能够有效地产生热量,单线态氧（¹O₂）与超氧根自由基（·O^-₂）...     

粒状土与结构接触面多重剪切边界面模型

针对工程中存在大量的土与结构物相互作用,使接触面的力学特性对土体和结构物的受力变形及其相互作用产生重要影响的问题,利用塑性滑移理论,将粗粒土与结构接触面的宏观变形分解为一个宏观法向变形和剪切面内一系列不同方向分布的相互独立虚拟微观剪切变形;通过虚功原理,在粒状土的状态相关和边界面弹塑性理论框架内建立一个粗粒土与结构接触面的多重剪切边界面模型.每个微观剪切变形包含一个微观剪应力-应变关系和一个微观应力-剪胀关系.引入一个与接触面土体密度和法向应力相关的状态参数,用以描述不同状态下土与结构接触面的变形和强度特性.对不同粗粒土与结构接触面在二维或三维应力条件下的单调和循环剪切试验进行模拟计算,模型预测与试验结果吻合良好,说明模型能够合理地描述粗粒土与结构接触面的非线性力学行为.     

Fuzzy控制的发电厂冷却水管网自动补水系统

通过对某发电厂冷却水管网补水系统工艺的分析,阐述了在该系统应用Ｆｕｚｚｙ控制的必要性,并用８０９８单片机构成了Ｆｕｚｚｙ控制器,实际运行情况表明,系统性能良好,可靠性高。     

基于Android平台的屏幕水雾手机游戏的设计与实现

随着Android手机系统的普及,各种Android应用程序如雨后春笋般一下多了起来。“屏幕水雾”是基于Android平台开发的手机游戏软件,软件采用Java语言开发,开发环境是Eclipse,其主要功能为使屏幕上生成一层水雾图像,可以用手指涂写,以图像的直观方式展现在用户面前。“屏幕水雾”这款手机游戏简单、新颖,符合年轻人的爱好特点。     

Metallo-Phthalocyanines Based Photocapacitors

Silicon - The novel metallo-phthalocyanines (4–6) were obtained from the reactions of gereniol substituted phthalonitrile compound (3) with corresponding metal salts (Co (II), Cu (II) and Zn...     

The effect of Er:YAG laser and bulk filled composite type on marginal adaptation of class II cavities: an SEM analysis study

Purpose: To evaluate the effect of cavity preparation method (Er:YAG laser or diamond bur) and bulk-filled composite material type on marginal adaptation mesial occlusal (MO) class II cavities. Materials and Methods: Two-surface box cavities (4-mm proximal depth and 5-mm occlusal width) were prepared on 60 human mandibular molar teeth. Cavities were prepared using Er:YAG laser or diamond burs in an air-turbine hand-piece. All cavities were applied Single Bond Universal dentin bonding agent. The cavities were further subdivided into three subgroups according to the restorative material used; two bulk-filled composites [Filtek Bulk Fill Posterior (3M ESPE) and SonicFill 2 (Kerr)] and one traditional composite material Filtek Ultimate Universal Restorative (3M ESPE). Restorations were evaluated using scanning electron microscopy at ×200 magnification for their adaptation to the approximal margins of the tooth. Results were analyzed using the two-way ANOVA and Tukey Post Hoc Test (p < 0.05). Results: A total of 900 SEM figures were obtained from all groups. Filtek Bulk Fill Posterior, SonicFill 2, and Filtek Ultimate Universal Restorative exhibited statistically similar gapped margins. However, the lowest scores of gapped margins were observed with SonicFill 2 (4.22%). Conclusions: Completely gap-free margins were not obtained with any of the tested materials. Bulk-fill composite materials showed similar marginal adapatation compared with standard composite. Marginal adaptation of Er:YAG laser prepared cavities was more irregular and had more gaps, but was statistically similar to diamond bur-prepared cavities.     

复合型软岩中大断面硐室联合支护技术应用

平煤六矿是一个年产350万t的大型现代化矿井,共分四个采区,各采区均有两条运输上(下)山及相应的皮带硐室和绞车硐室,属于永久硐室。各硐室均采用传统的锚喷支护,在使