Novel Direct Nanopatterning Approach to Fabricate Periodically Nanostructured Perovskite for Optoelectronic Applications

While indirectly patterned organic–inorganic hybrid perovskite nanostructures have been extensively studied for use in perovskite optoelectronic devices, it is still challenging to directly pattern perovskite thin films because perovskite is very sensitive to polar solvents and high‐temperature environments. Here, a simple and low‐cost approach is proposed to directly pattern perovskite solid‐state films into periodic nanostructures. The approach is basically perovskite recrystallization through phase transformation with the presence of a periodic mold on an as‐prepared solid‐state perovskite film. Interestingly, this study simultaneously achieves not only periodically patterned perovskite nanostructures but also better crystallized perovskites and improved optical properties, as compared to its thin film counterpart. The improved optical properties can be attributed to the light extraction and increased spontaneous emission rate of perovskite gratings. By fabricating light‐emitting diodes using the periodic perovskite nanostructure as the emission layers, approximately twofold higher radiance and lower threshold than the reference planar devices are achieved. This work opens up a new and simple way to fabricate highly crystalline and large‐area perovskite periodic nanostructures for low‐cost production of high‐performance optoelectronic devices.     

喹啉-4-甲醛缩氨基硫脲的合成及其对H~+的响应

利用氨基硫脲和喹啉-4-甲醛为原料,无水乙醇为溶剂,在冰醋酸作催化剂的条件下回流合成喹啉-4-甲醛缩氨基硫脲(QLATS),测定了熔点、紫外和红外光谱。利用紫外-可见吸收光谱探究了其对H~+的影响。QLATS溶液的吸收峰位于352 nm处,随着酸性的增强,QLATS的吸收带发生红移,同时吸收光谱形状和强度也逐渐发生变化。在pH=7.22时QLATS为无色,酸性条件下呈黄色。方法操作简便,具有良好的灵敏度。     

聚乙二醇介质中纳米Fe-Mn催化剂的F-T合成反应性能

采用化学还原法在乙二醇/水混合溶剂中制备纳米Fe-Mn催化剂,考察其在液态聚乙二醇中的F-T合成反应性能。透射电子显微镜、X射线衍射、穆斯堡尔谱和X射线光电子能谱等表征结果表明,纳米Fe-Mn催化剂粒径为(20~50)nm,具有铁磁性非晶结构,Mn主要富集在催化剂表面,Mn的加入使Fe更富电子,催化剂更易碳化。纳米Fe-Mn催化剂表现出很高的F-T反应活性,Mn的加入有利于催化剂的链增长反应,使产物分布向重质烃方向偏移。     

插铣不锈钢Cr13的铣削力建模分析

在瞬时刚性力模型的基础上搭建了插铣铣削力理论模型,通过加工不锈钢Cr13确定了模型方程中的铣削力系数。经MATLAB仿真并与切削试验结果对比,验证了该理论模型的可行性以及插铣Cr13的铣削力系数的准确性。     

叶片型面在线自动测量方法

为了实现叶片型面的在线自动测量,提出了一种基于机器视觉技术和机器人相结合的叶片型面测量方法。通过机器人带动叶片回转,由扫描仪获取不同视角下叶片型面的点云数据,根据旋转拼接原理将点云数据拼接到一起,完成叶片型面的测量。阐述采用机器人进行旋转拼接的原理,提出一种自动标定机器人法兰盘回转轴线的方法,利用该方法可在线完成扫描仪与机器人法兰盘之间位置关系的标定。试验表明,该方法简单有效,拼接后的叶片表面光滑,无分层现象,可实现叶片型面的在线自动测量。     

大学校园空间形态设计思考及其实践

通过国内外大学校园空间形态变化历史的分析，指出校园空间形态构成要素组织及其规划设计原则．结合近期正在实施的华中师范大学分校校园规划，对我国当前大学校园另辟分校的校园空间形态规划设计作了有益的探索。     

建筑多样性的探索:汉口火车站改造设计

城市背景在中国交通史上,武汉就以其优越的地理位置、素有九省通衢之称,其东西向的长江水运和南北向的京汉铁路和粤汉铁路,构成我国相当长历史时期的华中区域性交通运输的主要格局,并在当时发挥了重要的作用。汉口站前     

中远程反舰导弹超视距攻击捕捉特性分析

介绍了中远程反舰导弹超视距射击原理,分析了影响捕捉概率的自控终点系统误差和自控终点随机误差．鉴于现在点射击方式下,影响随机误差的众多因素中,惯导误差、目标指示误差和目标机动误差占主要方面,得出相应的自控终点随机误差近似公式．在此基础上建立了中远程反舰导弹超视距射击捕捉概率模型,并以某型导弹为例,对导弹超视距捕捉特性进行了实例分析．     

Transport and retention of a bacteriophage and microspheres in saturated, angular porous media: effects of ionic strength and grain size

Eight saturated column experiments were conducted to examine the effects of solution chemistry and grain size on the transport of colloids through crushed silica sand. Two sizes of colloids, 0.025-μm bacteriophage (MS-2) and 1.5-μm carboxylated microspheres, were used as surrogates for the transport of pathogenic viruses and bacteria, respectively. Increasing the Ca²⁺ concentration from 1 to 4.8 mM (along with background monovalent ions) resulted in complete attenuation (>6-log decrease in C/C₀) of MS-2, but caused only a 1-log reduction (C/C₀ = 0.1) in the concentration of the microspheres. Decreasing grain size from medium sand (d₅₀ = 0.70 mm) to fine sand (d₅₀ = 0.34 mm) resulted in substantial decreases in effluent concentrations of both the MS-2 (5-log decrease) and microspheres (>2.5-log decrease). Comparison of observed colloid retention to that predicted by a recently published correlation equation for colloid filtration revealed that the model can considerably underpredict (by 4 orders of magnitude or more) colloid retention by angular sand over distances as short as 20 cm. This indicates that state-of-the-art colloid filtration models are still limited in applicability to natural systems.     

美国建筑策划工具演变研究

在对美国建筑策划工具评介基础上,梳理其历史脉络,探寻未来发展趋势;在方法上,着重于挖掘各类工具综合使用方式,力图为我国策划实践根据实际国情选取合理的策划工具提供参考.