Nanocrystallization and optical properties of CsPbBr3−xIx perovskites in chalcogenide glasses

The confinement of CsPbX₃ (X = Cl, Br, and I) perovskite nanocrystals (NCs) in a stabilized inorganic glass matrix is a new strategy for improving their long-term stability and promoting their applications in the optoelectronic field. Here, in situ nanocrystallization strategy is developed to precipitate CsPbBr_3?xI_x NCs with arbitrary I/Br ratio among an elaborately designed GeS₂–Sb₂S₃-based chalcogenide glass matrix. Spherical CsPbBr_3?xI_x NCs are homogeneously distributed in the glass matrix after thermal treatment. The photoluminescence (PL) spectra show that the emission peaks of CsPbBr_3?xI_x NCs can be tuned from 570 nm to 722 nm with the replacement of Br by I. The fs transient absorption (TA) spectra reveal that there exists some structural defects in the NCs, leading to short PL decay life. This work would shed light on confining CsPbX₃ NCs into glassy matrices, facilitating their future applications in photoelectronic fields.     

Stick-Breaking Dependent Beta Processes with Variational Inference

Neural Processing Letters - The beta processes (BP) is a powerful nonparametric tool in feature learning, which is often used as the prior of Bernoulli process for choosing features from a feature...     

含损伤软化材料层合板承压时的分叉分析

本文讨论了由纤维和树脂-损伤应变软化材料组成的层合板在面内受压时的压缩分叉。用有限变开理论和半解析有限元法建立了相应的分叉方程,并进行数值模拟。计算结果表明,分叉将在损伤材料的应变软化阶段发生,为剪切带形分叉,损伤材料骨有剪应变集中,而且在纤维和树脂的界面附近有较大的剪应变突变等现象。     

气敏薄膜的光学机理研究

本文根据光传输理论导出介导消光系数，折射率与介质电磁参数，光波频率，电偶极子浓度及迁移率等的关系，分析了光激发与增加气敏介质的氧吸附的规律，结合实验说明气敏薄膜的光学变化机制。     

燕化公司网络病毒防治系统的实现

结合燕化公司网络病毒防治系统的实施，介绍了公司网络病毒防治系统的体系结构，并对公司网络病毒防治系统的运行管理提出了看法。     

磁致冷材料研究进展

介绍了磁致冷材料磁热效应的表征方法，概述了国内外各温度区间磁致冷材料的研究进展。在20K以下温区，磁致冷材料研究主要集中在具有高导热率、低点阵热容和极低有序化温度的石榴石，如Gd3Ga5O12(GGG)，Dy3Al5O12(DAG)，Gd3Ga5-xFexO12(GGIG)及Er基磁致冷材料；20K～77K温度区间，磁致冷材料研究主要集中在重稀土金属间化合物中，如(Dy1-xErx)Al2复合材料等；在室温附近，具有大磁热效应的磁致冷材料以稀土Gd，Gd5(SixGe1-x)4(0≤x≤0．5)和MnFeP1-xAsx(0．15≤x≤0．66)合金为代表，特别是Gd5Si2Ge2(Tc=274K)和MnFeP0.45As0.55(Tc=300K)合金，在磁场5T下具有巨磁热效应，是Gd的2倍以上。总结了各温度区间磁致冷材料的选择依据。重点评述了室温磁致冷材料的最新研究成果，展望了室温磁致冷材料的发展前景。     

采用重稀土改善焊缝韧性的研究

用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X 射线能谱仪(EDAX)研究了重稀土元素对低合金钢焊缝金属韧性的影响.结果发现,采用适当的焊条药皮配方和焊接工艺可使重稀土元素微量过渡到焊缝金属中(约10ppm),减少了夹杂物的面密度和面积百分数,显著提高了焊缝金属的低温韧性。夹杂物的减少和低温韧性的提高有很好的对应关系,因此可以认为,重稀土元素对焊缝金属的净化和变质作用是提高焊缝低温韧性的主要原因。此外,还对焊缝金属中夹杂物的类型进行了较深入的鉴别。     

Active learning of Gaussian processes with manifold-preserving graph reduction

As a recently proposed machine learning method, active learning of Gaussian processes can effectively use a small number of labeled examples to train a classifier, which in turn is used to select the most informative examples from unlabeled data for manual labeling. However, in the process of example selection, active learning usually need consider all the unlabeled data without exploiting the structural space connectivity among them. This will decrease the classification accuracy to some extent since the selected points may not be the most informative. To overcome this shortcoming, in this paper, we present a method which applies the manifold-preserving graph reduction (MPGR) algorithm to the traditional active learning method of Gaussian processes. MPGR is a simple and efficient example sparsification algorithm which can construct a subset to represent the global structure and simultaneously eliminate the influence of noisy points and outliers. Thereby, when actively selecting examples to label, we just choose from the subset constructed by MPGR instead of the whole unlabeled data. We report experimental results on multiple data sets which demonstrate that our method obtains better classification performance compared with the original active learning method of Gaussian processes.     

矿产勘查生产要素配置中政府和市场作用分析

矿产资源是经济社会发展的重要物质基础,是国家安全的战略保障。党的二十大要求“构建全国统一大市场,深化要素市场化改革,建设高标准市场体系”,强调“充分发挥市场在资源配置中的决定性作用,更好发挥政府作用”。本文分析了近年来矿产勘查生产要素配置现状,梳理了矿产勘查中政府和市场关系演变和作用机制,从充分发挥市场决定性作用、构建“有效市场”和更好发挥政府作用、塑造“有为政府”两个方面提出对策建议,以期为充分发挥政府和市场两个主体在矿产勘查生产要素配置中的作用提供一些思路。     

基于物联网实验室环境远程监测系统的研究

实验室环境对电子仪器及设备的使用安全和寿命以及实验室消防安全有着非常重大的影响,传统实验室环境监控需要安排人员进行24 h值班和巡检,人力投入和安装布线成本非常高;针对上述问题,采用高性能低功耗离子式烟雾传感器NIS-07和温湿度复合传感器DTH11进行环境数据的采集,采用无线网络模块完成数据的传输,并通过微处理器将采集的数据上传服务器,同时采用基于BP神经网络PID控制算法实现在线动态温湿度调控;服务器端使用Tomcat web服务器,采用MySQL数据库进行数据存储,并通过Java编程语言实现传感器数据的存储、分析、处理以及客户端数据的更新;客户端通过Web网页或APP对实验室环境进行实时监控,从而实现精确和高效的实验室环境远程集中管理.