改善铜蒸气激光输出特性的研究

介绍了铜蒸气激光器的发展及其输出特性。总结了近年来改善铜蒸气激光输出特性的研究。     

Phase diagrams of Sc-M(IV–VII)-C systems

Translated from Poroshkovaya Metallurgiya, No. 9(321), pp. 49–57, September, 1989.     

柳河大米产地环境及其矿物元素分布特征的典范对应分析

为筛选稳定可靠的柳河大米产地确证元素,通过2 次典范对应分析研究影响吉林省柳河大米采样点分布的环境因子,分析大米产地确证元素在区域尺度内的影响关系及其稳定性。典范对应分析结果表明,2 个环境梯度轴分别解释大米矿物元素含量总方差的17.3%和23.4%,柳河大米矿物元素含量和环境变量之间存在较强的空间相关性,受产地环境变量影响最大的为Se元素,Ca、Zn、Mg含量受其影响最小,Mg、Ca、Na、Mn、Zn具有较好的稳定性和空间代表性,可作为柳河大米产地确证的指标元素。研究结果为建立柳河大米确证模型提供有效的理论依据。     

Creep of Textile-Reinforced Composite Under Static and Cyclic Loads

Strength of Materials - The paper considers the creep of a textile-reinforced thermoplastic composite with a glass filler under the action of a combined short-term cyclic and long-term static...     

Structural Features and Tribological Properties of Multilayer Coatings Based on Refractory Metals

A comparative analysis of the structural features and tribological properties of multilayer coatings based on refractory metal compounds has been conducted in this review. Features of formation of the electronic structure of the synthesized coatings have been discussed, and the effect of methods and conditions of deposition on changes in the physicomechanical characteristics of nanocrystalline structures based on transition metal nitrides has been shown. Dependences of antifriction properties, corrosion resistance, and thermal stability on the modulation period (Λ) and the number of bilayers in the studied multilayer coatings have been determined. A decrease in the modulation period of individual layers in a coating positively affects the oxidation resistance of the coating, while an increase in the number of interfaces between the layers slows down the diffusion of oxygen atoms deep into the coating and, thereby, increases the protective properties of the multilayer system as a whole. The effect of the droplet component in cathodic-arc coatings on corrosion development mechanisms in corrosive media has been shown. A class of multifunctional multilayer coatings with an adaptive friction mechanism, which is characterized by a change in the properties and structure during tribological tests, has been discussed separately.     

豚草及三裂叶豚草挥发物成分的GC和GC／MS分析

本文运用ＸＡＤ－４和ＧＤＸ１０４树脂吸附的方法，对豚草（Ａｍｂｒｏｓｉａａｒｔｅｍｉｓｓｉｆｏｌｉａ）和三裂叶豚草（Ａ．ｔｒｉｆｉｄａ）的挥发物进行了研究，发现ＸＡＤ－４和ＧＤＸ１０４在吸附两种杂草挥发物的性能上基本相同．豚草挥发物的主要成分为：α－蒎烯、β－蒎烯、莰烯、２－冰片烯；三裂叶豚草的挥发物主要为：２，４－二甲基瘐烷、α蒎烯、２，６，７－三甲基癸烷、５－甲基壬烷、２－冰片烯．这些研究结果表明两种豚草挥发物的成分差别较大，对进一步研究它们的化感作用有重要意义。     

基于数据流深度学习算法的Android恶意应用检测方法

目前针对未知的Android恶意应用可以采用机器学习算法进行检测,但传统的机器学习算法具有少于三层的计算单元,无法充分挖掘Android应用程序特征深层次的表达。文中首次提出了一种基于深度学习的算法DDBN （Data-flow Deep BeliefNetwork）对Android应用程序数据流特征进行分析,从而检测Android未知恶意应用。首先,使用分析工具FlowDroid和SUSI提取能够反映Android应用恶意行为的静态数据流特征;然后,针对该特征设计了数据流深度学习算法DDBN,该算法通过构建深层的模型结构,并进行逐层特征变换,将数据流在原空间的特征表示变换到新的特征空间,从而使分类更加准确;最后,基于DDBN实现了Android恶意应用检测工具Flowdect,并对现实中的大量安全应用和恶意应用进行检测。实验结果表明,Flowdect能够充分学习Android应用程序的数据流特征,用于检测未知的Android恶意应用。通过与其他基于传统机器学习算法的检测方案对比,DDBN算法具有更优的检测效果。     

Colloidal Nanosurfactants for 3D Conformal Printing of 2D van der Waals Materials

Printing techniques using nanomaterials have emerged as a versatile tool for fast prototyping and potentially large-scale manufacturing of functional devices. Surfactants play a significant role in many printing processes due to their ability to reduce interfacial tension between ink solvents and nanoparticles and thus improve ink colloidal stability. Here, a colloidal graphene quantum dot (GQD)-based nanosurfactant is reported to stabilize various types of 2D materials in aqueous inks. In particular, a graphene ink with superior colloidal stability is demonstrated by GQD nanosurfactants via the π–π stacking interaction, leading to the printing of multiple high-resolution patterns on various substrates using a single printing pass. It is found that nanosurfactants can significantly improve the mechanical stability of the printed graphene films compared with those of conventional molecular surfactant, as evidenced by 100 taping, 100 scratching, and 1000 bending cycles. Additionally, the printed composite film exhibits improved photoconductance using UV light with 400 nm wavelength, arising from excitation across the nanosurfactant bandgap. Taking advantage of the 3D conformal aerosol jet printing technique, a series of UV sensors of heterogeneous structures are directly printed on 2D flat and 3D spherical substrates, demonstrating the potential of manufacturing geometrically versatile devices based on nanosurfactant inks.     

Effect of Hydraulic Liquid and Sea Water on the Mechanical Characteristics of Polymeric Fibrous Structures

Strength of Materials - The degradation of the mechanical characteristics of typical composite materials under the action of the working liquid is studied. Polypropylene and epoxy specimens...