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Design strategy of porous elastomer substrate and encapsulation forinorganic stretchableelectronics

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International Journal of Smart and Nano Materials 2024年第2期15卷 330-347页

作者： Jiaxin Li Xianhong Meng Yunfei Shen Junlin Gu Guoquan Luo Ke bai Hailong Li Zhaoguo Xue National Key Laboratory of Strength and Structural Integrity Institute of Solid MechanicsSchool of Aeronautic Science and EngineeringBeihang UniversityBeijingP.R.China Applied Mechanics Laboratory Department of Engineering MechanicsTsinghua UniversityBeijingP.R.China

The emergence of stretchable electronic technology has led to the development of many industries and facilitated many unprecedented applications,owing to its ability to bear var-ious ***,conventional solid elastomer sub-strates and encapsulation can severely restrict the free motion and deformation of patterned interconnects,leading to poten-tial mechanical failures and electrical *** address this issue,we propose a design strategy of porous elastomer substrate and encapsulation to improve the stretchability of serpentine interconnects in island-bridge *** ser-pentine interconnects are fully bonded to the elastomer sub-strate,while segments above circular pores remain suspended,allowing for free deformation and a substantial improvement in elastic stretchability compared to the solid *** pores ensure unimpeded interconnect deformations,and mod-erate porosity provides support while maintaining the initial planar *** to conventional solid configurations,finite element analysis(FEA)demonstrates a substantial enhancement of elastic stretchability(e.g.=9 times without encapsulation and=7 times with encapsulation).Uniaxial cyc-lic loading fatigue experiments validate the enhanced elastic stretchability,indicating the mechanical stability of the porous *** its intrinsic advantages in permeability,the pro-posed strategy has the potential to offer insightful inspiration and novel concepts for advancing the field of stretchable inorganic electronics.

关键词： Stretchable inorganic electronics Island-bridge structures porous elastomer substrate encapsulation design serpentine interconnects

基于改进麻雀搜索算法优化LSTM的滚动轴承故障诊断

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工程科学与技术 2024年第2期56卷 289-298页

作者：周玉房倩裴泽宣白磊华北水利水电大学电气工程学院河南郑州450045

为了对滚动轴承的工作状态及故障类别进行准确的诊断,本文采用长短时记忆(LSTM)神经网络作为分类器对滚动轴承数据集进行分类诊断。首先,从滚动轴承原始运行振动信号中提取时域和频域特征参数,组成具有高维特征参数的数据集;使用核主成... 详细信息

为了对滚动轴承的工作状态及故障类别进行准确的诊断,本文采用长短时记忆(LSTM)神经网络作为分类器对滚动轴承数据集进行分类诊断。首先,从滚动轴承原始运行振动信号中提取时域和频域特征参数,组成具有高维特征参数的数据集;使用核主成分分析(KPCA)方法对高维特征集进行降维处理,选取重要性程度高的特征构成输入特征向量。然后,针对LSTM神经网络在滚动轴承故障诊断中存在的超参数难以确定的问题,提出一种基于自适应t分布策略的麻雀搜索算法优化LSTM神经网络的故障诊断方法(tSSA–LSTM)。最后,使用凯斯西储大学滚动轴承数据中心的数据进行故障诊断精度测试、泛化性能测试及噪声环境下故障诊断性能测试等多个仿真实验,并将本文提出的诊断模型与麻雀搜索算法优化长短时记忆神经网络(SSA–LSTM)、遗传算法优化长短时记忆神经网络(GA–LSTM)、粒子群算法优化长短时记忆神经网络(PSO–LSTM)及传统LSTM诊断模型进行对比。结果表明:tSSA可以更有效地对LSTM的隐含层神经元数量、周期次数、学习率等超参数进行合理优化;所提方法的平均诊断准确率达到98.86%,交叉验证平均诊断结果为98.57%;所提方法在噪声干扰下的故障诊断准确率也优于对比方法。因此,本文提出的tSSA–LSTM模型不仅可以更精准地诊断滚动轴承故障状态,而且具有更强的泛化能力及抗干扰能力,有效地提高了滚动轴承故障诊断的性能。

关键词：麻雀搜索算法故障诊断长短时记忆神经网络特征提取滚动轴承

氮化硼的介电特性及其在微波加热中的热透波性能

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工程科学与技术 2024年第2期56卷 118-128页

作者：张利尚小标白永珍李广超肖利平济宁学院机电工程学院山东曲阜273155 昆明理工大学机电工程学院云南昆明650500 非常规冶金教育部重点实验室云南昆明650093 微波能工程应用及装备技术国家地方联合工程实验室云南昆明650093

耐火结构的热透波性能对微波加热的模式和效率均具有重要影响,所以明确耐火结构在微波加热过程中的动态热透波性能变化至关重要。本文以氮化硼陶瓷为研究对象,通过实验测试了其在915 MHz、2 450 MHz两种频率下的宽温域(25~1 000℃)介电... 详细信息

耐火结构的热透波性能对微波加热的模式和效率均具有重要影响,所以明确耐火结构在微波加热过程中的动态热透波性能变化至关重要。本文以氮化硼陶瓷为研究对象,通过实验测试了其在915 MHz、2 450 MHz两种频率下的宽温域(25~1 000℃)介电特性,采用传输线理论计算了氮化硼陶瓷的功率透过系数,并对其介电常数、介电损耗因子等参数的温度特性进行了分析。研究表明:25~1 000℃,两种频率下的介电常数变化幅度较小,介电常数仅变化了1.8%左右;两种频率下的介电损耗因子随温度呈波动性变化,900℃之后都呈指数增长的趋势。微波在氮化硼陶瓷中的波长和穿透深度均随温度的增加呈现下降趋势;当频率增大时,穿透深度随频率的增大而减小。氮化硼陶瓷的透波性能在两种极化模式下存在明显差异,水平极化(TM)明显高于垂直极化(TE)。当频率为915 MHz时,可以考虑材料厚度值为0.08 m左右作为优化材料厚度,同时以入射角度在θ_(i)≤67°范围内入射具有良好的透波性能(PTC≥0.7)。当频率为2 450 MHz时,可以考虑材料厚度值为0.06 m作为优化材料厚度,在TE极化模式中应优先考虑微波入射角度在θ_(i)≤58°范围内入射,在TM极化模式中建议入射角度θ_(i)≤77°入射具有较好的透波效果(PTC≥0.9)。本研究对微波加热设备内炉衬材料的选择、工艺参数的设定以及有效提高微波能的利用率具有重要的现实指导意义。

关键词：微波加热氮化硼透波性能介电常数耐火结构

Symbiotic bacteria attenuate Drosophila oviposition repellence to alkaline through acidification

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Insect Science 2021年第2期28卷 403-414页

作者： Wei Liu Jie Wang Hong-Yu Zhang Ying-Chun Yang Ru-Xue Kang Peng bai Hui Fu Li-Rong Chen Yan-Ping Gao eng King Tan Department of Medical Laboratory Science Fenyang CollegeShanxi Medical UniversityShanxiChina Department of Neurology National Neuroscience InstituteSingapore General Hospital CampusSingapore Department of Basic Medical Fenyang CollegeShanxi Medical UniversityShanxiChina

Metazoans harbor a wealth of symbionts that are ever-changing the environment by taking up resources and/or excreting *** such common environmental modification is a change in *** wisdom holds that symbionts facilitate the survival and production of their hosts in the wild,but this notion lacks empirical ***,we report that symbiotic bacteria in the genus Enterococcus attenuate the oviposition avoidance of alkaline environments in *** studied the effects of alkalinity on oviposition preference for the first time,and found that flies are robustly disinclined to oviposit on alkali-containing *** innate repulsion to alkaline environments is explained,in part,by the fact that alkalinity compromises the health and lifespan of both offspring and parent *** dramatically diminished or even completely reversed the ovipositional avoidance of alkalinity in ***,Enterococcus generate abundant lactate during fermentation,which neutralizes the residual alkali in an egg-laying *** conclusion,Enterococcus protects Drosophila from alkali stress by acidifying the ovipositional substrate,and ultimately improves the fitness of the Drosophila *** results demonstrate that symbionts are profound factors in the Drosophila ovipositional decision,and extend our understanding of the intimate interactions between Drosophila and their symbionts.

关键词： acidification alkaline Drosophila,Enterococcus fitness oviposition

飞机荷载桥梁装配式主梁横向新型连接方案及其静动力性能分析

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工程科学与技术 2024年第4期56卷 98-107页

作者：王琳白增庆江辉曹铁志宋光松吴松华任阳民航机场规划设计研究总院有限公司北京100029 北京交通大学土木建筑工程学院北京100044

针对既有装配式主梁铰缝连接强度弱、湿连接施工复杂等问题,充分考虑飞机荷载桥梁荷载集度大、空间受力显著等特点,提出一种剪力键和横向预应力筋混合连接的装配式主梁连接方案。该方案通过剪力键与键槽实现相邻主梁拼接,采用横向预应... 详细信息

针对既有装配式主梁铰缝连接强度弱、湿连接施工复杂等问题,充分考虑飞机荷载桥梁荷载集度大、空间受力显著等特点,提出一种剪力键和横向预应力筋混合连接的装配式主梁连接方案。该方案通过剪力键与键槽实现相邻主梁拼接,采用横向预应力筋为接缝界面提供压应力储备,具有结构整体性好、施工方便等优点。以某机场滑行道桥为对象,基于ABAQUS平台建立新型连接装配式主梁的非线性数值模型,开展静、动力学性能分析以验证方案的可靠性,揭示了剪力键位置、数量、高度及初始预应力对主梁力学行为和抗震性能的影响规律。结果表明:飞机静载作用下,该方案能够满足规范对于主梁挠度限值的要求且具有可观的安全储备。增设跨中剪力键及增加其数量可显著降低主梁跨中挠度和弯矩;相较于仅设置梁端剪力键,加设3道跨中剪力键可使静载下力学响应分别降低19.92%、23.35%,使地震下力学响应分别降低17.29%、40.12%。剪力键倾角和高度对主梁受力影响较小,增大横向预应力筋初始张拉力可有效提高主梁接缝界面的预压应力,静载、地震下的最大增幅分别为45.31%、46.51%。研究成果可为飞机荷载桥梁的主梁拼装提供重要的技术支撑,并可拓展应用于重载公路、铁路桥梁。

关键词：飞机荷载桥梁装配式主梁剪力键横向预应力筋静力性能抗震性能

8.8级非调紧固件用10B21盘条研究与开发

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特殊钢 2024年第1期45卷 23-26页

作者：孔祥伟白云张剑锋江阴兴澄特种钢铁有限公司特钢研究院江阴214400

采用转炉→精炼炉→真空脱气→方坯连铸→加热→粗轧→中轧→精轧→减定径→吐丝→XDWP(Xingcheng Direct Water Patenting)冷却→斯太尔摩风冷冷却的方式试验生产基于10B21钢的8.8级非调紧固件用热轧盘条。通过控制减定径温度为813℃,... 详细信息

采用转炉→精炼炉→真空脱气→方坯连铸→加热→粗轧→中轧→精轧→减定径→吐丝→XDWP(Xingcheng Direct Water Patenting)冷却→斯太尔摩风冷冷却的方式试验生产基于10B21钢的8.8级非调紧固件用热轧盘条。通过控制减定径温度为813℃,吐丝温度为828℃,斯太尔摩辊道速率设置为0.75 m/s,在连续经过XDWP冷却和斯太尔摩风冷后获得的热轧盘条抗拉强度达到680 MPa,断后伸长率为23.6%,断面收缩率为75%,力学性能完全满足GB/T 29087―2012的要求。且经过1/4冷顶锻和25%的大减面率拉拔试验,其结果满足紧固件用户使用要求。

关键词： 8.8级非调紧固件 10B21钢 XDWP 贝氏体

NUMERICAL SIMULATION OF SEPARATED FLOW NEAR GROYNE

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Journal of Hydrodynamics 2002年第4期14卷 47-52页

作者： Jiang, Chang-Bo Chen, Yong-Kuan bai, Yu-Chuan Zhao, Zi-Dan Dept. of River and Coast eng. Changsha Commun. Univ. Changsha 410076 China Dept. of Hydraulic.eng. Tsinghua Univ. Beijing 100084 China Inst. of sediment on River eng. Tianjian Univ. Tianjian 300072 China

A numerical model was developed to simulate the flow around non-submeged groyne in two dimensions, which was based on N-S equations with Smagorinsky's subgrid-scale turbulence model. Flow phenomenon and results measured practically agree with the calculation results very well, and this model could be used to simulate the characteristics of the eddies of upper and down reaches around spur-dikes successfully.

关键词： Computational fluid dynamics Computer simulation Erosion Mathematical models Navier Stokes equations Turbulent flow

Efficient Extraction of Lithium Ions from High Mg/Li Ratio Brine through the Synergy of TBP and Hydroxyl Functional Ionic Liquids

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Chinese Journal of Chemistry 2020年第12期38卷 1743-1751页

作者： Ruibing bai Junfeng Wang Li Cui Shicheng Yang Wei Qian Penglei Cui Yanqiang Zhang Beijing Key Laboratory of Ionic Liquids Cleon Process Institute of Process EngineeringChinese Academy of SciencesBeijing 100049China Sino-Donish College University of Chinese Academy of SciencesBeijing 100049China Zhengzhou Institute of Emerging Industrial Technology ZhengzhouHenan 450000China Institute of Resources and Environment engineering Shanxi UniversityState Environmental Protection Key Laboratory of Efficient Utilization of Waste ResourcesTaiyuanShanxi 030006China

of main observation and conclusion The extraction of Li^+from the high Mg/Li ratio brine was performed using hydroxyl functional ionic lic-uids(ILs)as the coextractant and tributyl phosphate(TBP)as the *** the extractive system,1-2-hydroxyethyl-3-mnethylimidazolumbis(trifuoromethylsulfonyl)imide([HOEmim][NTf2])+TBP was proved to exhibit the highest extraction efficiency of Li^+(88.15%)from licl aqueous solutions among the extractants composed of differents TB P,and ls+*** of various extraction parameters on the extraction eficiencies of Li^+and Mg^2+were then investigated.95.01%of Li^+was extracted and the Li^+/Mg^2+separation factor reached 405.76 in a singl-stage at 278.15 Kand O/A of 2:*** extraction complexes were determined by the slope analysis method and ESI-MS analysis,and the metal complexes in the organic phase were indcated to be mainly[L-2TBP][NTf;*** striping study showed that 92.86%of i*was stripped with 1.0 mol·L^-1 HCl.98%extraction capacity of the synergyextractants was remained after 5 regeneration *** thermodynamic parameters(△G°,△H°,and△S°),together with the mechanism of the Li^+extraction were further demonstrated finally,According to the results,[HOEmim][NTf2]+TBP extraction system showed promising performance in extracting lithium from salt lake brine with high Mg/Li ratio.

关键词： complexes system strip

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幼年性息肉病的临床病理学特征及研究进展

中华结直肠疾病电子杂志 2024年第1期13卷 21-25页

作者：何宗杰白辰光高显华张卫海军军医大学第一附属医院(上海长海医院)病理科上海200433 海军军医大学第一附属医院(上海长海医院)肛肠外科上海200433

幼年性息肉病(JPS)是一种常染色体显性遗传的错构瘤性息肉综合征,以胃肠道出现多发幼年性息肉为主要表现,以结直肠息肉多见。JPS患者存在极高的胃肠道肿瘤发生风险,多数为结直肠癌,尽早检出尤为重要。JPS患者的幼年性息肉随疾病进展而... 详细信息

幼年性息肉病(JPS)是一种常染色体显性遗传的错构瘤性息肉综合征,以胃肠道出现多发幼年性息肉为主要表现,以结直肠息肉多见。JPS患者存在极高的胃肠道肿瘤发生风险,多数为结直肠癌,尽早检出尤为重要。JPS患者的幼年性息肉随疾病进展而呈现多样性的病理组织学表现,甚至出现腺瘤或腺癌结构,基因检测有助于精准诊断。约60%的JPS患者存在SMAD4和BMPR1A基因的胚系突变,PTEN、eng和FOCAD等基因改变在少数病例中也有发现。JPS的治疗一般采取息肉切除或脏器切除,近年来在药物治疗方面也有所进展。

关键词：肠息肉病幼年性息肉病幼年性息肉临床表现组织病理学分子遗传学