摘要：Four machine learning algorithms were used to predict the solid solution phases of high-entropy alloys(HEAs).To improve the model accuracy,the K-fold cross validation was *** show that the K-nearest neighbor algorithm can effectively distinguish body-centered cubic(bcc)phase,face-centered cubic(fcc)phase,and mixed(fcc+bcc)phase,and the accuracy rate is approximately 93%.Thereafter,CoCrFeNi_(2)Al_(x)(x=0,0.1,0.3,1.0)HEAs were prepared and characterized by X-ray diffractometer and energy disperse *** is found that their phases are transformed from fcc phase to fcc+bcc phase,which is consistent with the prediction results of machine ***,the influence of Al content on the microstructure and tribological properties of CoCrFeNi_(2)Al_(x)(x=0,0.1,0.3,1.0)HEAs was *** reveal that with the increase in Al content,the nanohardness and microhardness increase by approximately 45%and 75%,*** elastic limit parameter H/Er increases from 0.0216 to 0.030,whereas the plastic deformation resistance parameter H^(3)/E_(r)^(2) increases from 0.0014 to 0.0045,which demonstrates an improvement in nanohardness with the increase in Al addition *** addition,the wear rate decreases by 35%with the increase in Al addition *** research provides a new idea with energy-saving and time-reduction characteristics to prepare HEAs.

摘要：在实际生活中,气体泄漏扩散情况会受到风向、风速及建筑物等影响,常见的气体扩散研究主要是在无降雨情况下对其他环境因素进行分析。以氨气为例,利用氨气极易溶于水的性质,以原有的高斯烟羽模型为基础,通过数值模拟进行分析,研究在雨季情况下,有害气体泄漏受降雨影响时的扩散情况。首先根据实际情况对高斯烟羽模型的有效源强进行改进,然后引入沉降系数表征降雨量对扩散的影响,在相同条件下进行模拟,将前两者的模拟结果与传统的高斯烟羽模型进行对比分析。试验结果表明,降雨量和有效源强对气体泄漏扩散有明显影响,与传统高斯烟羽模型相比,改进后的高斯烟羽模型更符合实际情况。

摘要：As system of a serial of technologies and engineering activities, remanufacturing aims at restoring and rebuilding waste machinery through advanced technologies and industrialized measures under the direction of the product total life cycle theory. With the development of surface engineering, nano-surface engineering has been one subject of intensive studies. In addition, nano-surface engineering has become an important means for property reforming and promoting of remanufacturing parts. Many low-dimension and nano-size or nano-structure functional coatings, which can improve materials properties evidently, are deposited by new methods. In this paper, some researches about the new achievement and remanufacturing application of the nano-stmctured coatings by different nano-surface engineering technologies in our laboratory were introduced. Especially, nano-structured DLC multilayer coatings by d.c. plasma CVD, nano-composed Al2O3/Ni, SiC/Ni and Diamond/Ni coatings by brush plating, and nano-composed Al2O3/TiO2 coating by plasma spraying were introduced in detail.

摘要：从古至今,由细微粒矿物(小于18μm)构成的无机矿物颜料被广泛应用于艺术品中,且艺术品的品质由矿物的粒径、种类等因素所决定,建立微区矿物颜料组成、分布的精准且无损的分析方法对于工艺开发、探究时代文化特征等具有重要意义。现有分析方法有颜色鉴定的色彩学分析,但受限于色差或色度而难以直接确定矿物的类别;此外,X射线衍射、扫描电镜-能谱等被应用于矿物成分鉴定,然而此类测试方法对样品有损伤风险、测试过程繁琐等不足,不利于文物保护或样品的再利用。本文基于激光拉曼光谱为微细粒矿物颜料提供无损分析方法,通过对25种常见无机矿物颜料进行532nm、638nm、785nm激光的拉曼光谱测试,建立了25种常见无机矿物颜料的拉曼光谱数据库。随后选用不同色系以及同色系的无机矿物颜料进行拉曼微区成像,在微区中能探测到1μm左右的细微粒矿物,且细微粒矿物颜料的拉曼指纹信息与建立的矿物颜料拉曼光谱数据库完全匹配,这为微细粒矿物颜料的组成和分布提供了精准分析的方法,适用多种微细粒矿物颜料的同时分析。

摘要：文学的实践创新引领文学观念发展与变革。叙事内镜手法的运用,有助于优化文学文本叙事模式与逻辑框架,构成多重文本叙事复合关系结构——文学文本的虚构化真实与真实化虚构的多重文本间性成为文本意义增殖的有效孵化器。虚构书籍作为未必真实存在于现实世界但“真实”镶嵌于文学文本的虚构文本,以叙事内镜为中介,实现原文学文本与虚构书籍文本间性运动。文本的虚构世界与现实的真实世界碰撞交融实现意义不断生成,为文本解读提供阐释与理解的广阔空间;同时,叙事内镜构建的多重文本叙事召唤结构驱动读者内心信念与对现实世界感悟不断交汇、扩容,继而重构读者对现实世界的深层认知,揭示了文本无限开放性与意义建构性特征。由此,文学的虚构世界与真实世界多维交织、互动重构而使之成为游走于真实与虚拟的双重性存在。

摘要：四开关升降压(four-switch Buck-Boost,FSBB)变换器凭借其出色的软开关特性、宽范围调压能力、输入输出电压极性相同等优势被应用在数据中心供电架构中。然而,FSBB变换器软开关控制方式的多控制自由度特性,使得其控制策略复杂多变、增加了效率优化的难度。针对以上问题,研究并设计一种多模式高效控制策略,以提高FSBB变换器在全负载范围内的转换效率。首先,在FSBB变换器零电压开通(zero voltage switch,ZVS)的基础上得到控制量的约束条件,并确定电感电流有效值最低时控制量的取值规则;然后,构建FSBB变换器完整的损耗模型,以总损耗最低为目标,提出一种多模式的高效控制策略,并通过数据拟合的方式进行控制量的设计;最后,在Simplis中仿真验证并制作一个300 W的实验样机。测试结果表明:所设计的实验样机能在全输入、输出电压范围和全负载范围内实现较高的转换效率。其中最高峰值效率达到98.5%、最高平均效率达到97.93%,开关频率范围为500 kHz~1 MHz。

摘要：以“小红书”平台中“奶爸”博主发布的短视频为研究样本,采用文本分析方法,探讨短视频中育儿场景、产品广告植入与父职展演之间的关系。研究发现:“奶爸”博主搭建的育儿场景可分为生活型、社交型、科普型三种;在育儿短视频中植入广告在一定程度上使得虚拟育儿与现实育儿场景交融;短视频内容丰富了男性育儿的角色与实践方式,有助于人们重新审视传统育儿分工中被虚化与边缘化的父职角色;品牌方与“奶爸”博主之间是双向选择、互相形塑的,“奶爸”博主在兼顾育儿与获得经济收入的同时也帮助品牌方塑造品牌形象。但是,“奶爸”博主在商业合作的过程中发布的短视频不同程度地呈现出了内容同质化、剧本化倾向,给大众造成了困扰。基于此,一方面,博主个人要注意维护自身形象,传递正确的价值观,严把产品质量关,核实相关信息的可靠性、真实性、科学性和适用性;另一方面,新媒体平台应该加强对博主和品牌方的监管,营造友好的网络育儿社区环境。

摘要：串联谐振型直流变换器(series-resonant DC-DC converter,SRC)是电力电子变压器的核心元件,但电容等储能元件体积大是制约电力电子变压器功率密度提高的重要因素之一,为此应尽量减小电容等无源元件体积。然而,当SRC直流侧电容减小,尤其是与谐振电容基本相当时,其高频环节电流特性与传统的直流电容较大的SRC存在很大不同。为解决上述问题,该文对比分析半桥型SRC、全桥型SRC和半桥全桥混合的SRC(混合型SRC)在不同直流电容与谐振电容比值情况下的高频环节电流特性,求解得到实现软开关时3种典型SRC开关频率设计应满足的超越方程,进一步得到其开关频率与谐振频率比值解析表达式,据此提出3种SRC高频环节开关频率设计方法。最后,通过实验验证高频环节特性分析正确性和所提出的开关频率设计方法有效性。

摘要：卫星物联网终端低功耗、轻控制的设计需求导致系统采用常规随机接入协议时易发生大量碰撞,难以满足系统吞吐量要求。现有容碰撞随机接入技术依赖功率控制、波形积累的方式,在实际中难以实现。该文分析了功率域碰撞分离所需条件,提出面向功率域信号分离的辅助波束设计方案,在常规接收波束外增设辅助接收波束,通过优化辅助波束增益构造接收信号信噪比差异,支撑碰撞信号分离。仿真表明,所提方案能够显著提升随机接入的吞吐量。

摘要：As the mining industry continues to expand and international oil prices increase,more rigorous demands are being placed on the design of mining *** this,there is an urgent need to develop new power-driven mining equipment to solve the problems of high energy consumption and insufficient power coupling of current *** study proposed a design of a hybrid power system for underground Load Haul Dump(LHD).The proposed design integrated Quality Function Deployment(QFD)and Theory of Inventive Problem Solving(TRIZ).It identified 7 user requirements and 10 related technical features,formulated 11 innovative design solutions,and ultimately adopting an electric drive hybrid power *** scheme effectively addressesd power transmission coupling problems and improve the efficiency of loaders.A 6 m³hybrid power loader prototype has been developed,which reduces operational energy consumption and advances the electrification and green,low-carbon evolution of mining equipment.