检索结果-南通市图书馆

An integration method based on a novel combined flow for aerodynamic configuration of strutjet engine

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第9期34卷 156-167页

作者： longsheng xue Chuan CHENG Chengpeng WANG Keming CHENG College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China Aerospace System Engineering Shanghai Shanghai 201100China

In this paper a novel design method of aerodynamic configuration is proposed to integrate forebody,strut and inlet for strutjet engine,and a model at design point of Mach number6 is generated to investigate the aerodynamic performance by both simulations and *** basic flow field employed by proposed method is a combined flow named IBB,which is combined by Internal Conical Flow A(ICFA),truncated Busemann flow I(BI)for external section,and truncated Busemann flow II(BII)for internal *** model configuration is generated by streamline tracing method from basic flow field,in which the forebody section is traced from ICFA and BI flows,and the inlet as well as strut section is traced from BII *** simulations in Mach number 4,5,and 6 demonstrate uniform starting flow fields with relatively high total pressure recovery,which agree well with experiments in wind ***,in low Mach number cases,this inlet could start at Mach number 3 while it is unstarted at Mach number 2.7;in high Mach number cases,a uniform flow could still exist in Mach number 6.5 while a relatively strong shock wave boundary layer interaction is found in cowl area of Mach number 7 case,indicating the inlet designed by proposed method works in a relatively wide Mach number range.

关键词： Airframe-propulsion integration Busemann flow Combined flow Hypersonics Wind tunnel test

Oblique shock train motion based on schlieren image processing

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第3期36卷 30-41页

作者： longsheng xue Chuan CHENG Chengpeng WANG Lantian ZHANG Kang LI Keming CHENG College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China Beijing Institute of Tracking and Telecommunication Technology Beijing 100094China Aerospace System Engineering Shanghai Shanghai 201109China

In this paper,shock train motion in a Mach number 2.7 duct is studied experimentally,and large numbers of schlieren images are obtained by a high-speed *** image processing method based on Maximum Correlation Detection(MCD)is proposed to detect shock train motion from the schlieren images,based on which the key structures,e.g.,separation positions and separation shock angles on the top and bottom walls,can be analysed in *** oscillations of the shock train are generated by rhombus and ellipse shafts at various excitation *** to the analysis of MCD results,the distributions of the frequency components of shock train oscillation generated by the two shafts are distinctly different,in which the motion generated by the ellipse shaft is much smoother;shock train motion is mainly characterized by the oscillation of separation position while the separation shock strength is not so sensitive to downstream disturbance;there is a hysteresis loop relation between the downstream pressure and separation position.

关键词： Frequency components Hysteresis loop Maximum Correlation Detection(MCD) Schlieren image processing Shock train oscillation

Analysis of Unstarted Hypersonic Flow Unsteadiness Based on Schlieren Image Processing

在线全文

学校读者我要写书评

暂无评论

Transactions of Nanjing University of Aeronautics and Astronautics 2019年第5期36卷 856-867页

作者： WANG Chengpeng WANG Wenshuo xue longsheng XU Pei YANG Jinfu College of Aerospace Engineering Nanjing University of Aeronautics & Astronautics

The unstarted flow field in a hypersonic inlet model at a design point of Ma 6 is studied *** time-resolved spatial flow characteristics of the separation shock oscillation,which is induced by the unstarted flow,are analyzed based on a high-speed Schlieren system and an image processing *** motion of the separation shock detected by the shock-detection algorithm is compared to the results of fast-response wall-pressure measurements,and good agreement is demonstrated by comparing the frequency components in the power spectral density contours between shock oscillation and pressure *** hysteresis of the pressure and separation shock during oscillation cycles is observed from the time history of the shock motion,which means that the unsteady flow pattern of the unstarted hypersonic flow can be accurately clarified by time-resolved Schlieren image *** results convincingly demonstrate that the shock-detection technique is successfully applied to an unstarted hypersonic flow case.

关键词： shock-detection system hypersonic inlet flow unstarted flow

Interpenetrated Structures for Enhancing Ion Diffusion Kinetics in Electrochemical Energy Storage Devices

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第11期16卷 718-728页

作者： Xinzhe xue longsheng Feng Qiu Ren Cassidy Tran Samuel Eisenberg Anica Pinongcos Logan Valdovinos Cathleen Hsieh Tae Wook Heo Marcus A.Worsley Cheng Zhu Yat Li Department of Chemistry and Biochemistry University of California1156 High StreetSanta CruzCA 95064USA Lawrence Livermore National Laboratory 7000 East AvenueLivermoreCA 94550USA

The architectural design of electrodes offers new opportunities for next-generation electrochemical energy storage devices(EESDs)by increasing surface area,thickness,and active materials mass loading while maintaining good ion diffusion through optimized electrode ***,conventional thick electrodes increase ion diffusion length and cause larger ion concentration gradients,limiting reaction *** demonstrate a strategy for building interpenetrated structures that shortens ion diffusion length and reduces ion concentration *** free-standing device structure also avoids short-circuiting without needing a *** feature size and number of interpenetrated units can be adjusted during printing to balance surface area and ion *** with a 3D-printed interpenetrated polymer substrate,we metallize it to make it *** substrate has two individually addressable electrodes,allowing selective electrodeposition of energy storage *** a Zn//MnO_(2) battery as a model system,the interpenetrated device outperforms conventional separate electrode configurations,improving volumetric energy density by 221%and exhibiting a higher capacity retention rate of 49%compared to 35%at temperatures from 20 to 0℃.Our study introduces a new EESD architecture applicable to Li-ion,Na-ion batteries,supercapacitors,etc.

关键词： Interpenetrated structure 3D printing Electrochemical energy storage Ion diffusion length Inter-electrode distance

在线全文

学校读者我要写书评

暂无评论

振动基座下光纤陀螺信号消噪方法对比研究

现代电子技术 2014年第4期37卷 156-158,162页

作者：李佳桐张春熹张指挥薛龙生徐雪洁北京航天航空大学仪器科学与光电工程学院中国人民解放军61135部队中国人民解放军95801部队

为了减小动态环境下光纤陀螺信号的随机误差,采取振动试验对光纤陀螺的动态误差进行激发,通过对试验数据的Allan方差分析,得到了振动过程中光纤陀螺信号随机误差的变化特性。采用基于AR(2)模型的Kalman滤波方法和小波滤波方法对光纤陀... 详细信息

为了减小动态环境下光纤陀螺信号的随机误差,采取振动试验对光纤陀螺的动态误差进行激发,通过对试验数据的Allan方差分析,得到了振动过程中光纤陀螺信号随机误差的变化特性。采用基于AR(2)模型的Kalman滤波方法和小波滤波方法对光纤陀螺信号进行消噪处理,分析结果显示上述两种方法都能够有效地消除振动基座下FOG信号的随机误差,并且小波滤波方法要优于Kalman滤波方法。

关键词：振动基座 Allan方差分析 Kalman滤波小波滤波消噪

LD泵浦Nd∶YVO_4/V∶YAG被动调Q1.34μm激光器

在线全文

学校读者我要写书评

暂无评论

光子学报 2005年第7期34卷 971-974页

作者：薛庆华郑权卜轶坤钱龙生中国科学院长春光学精密机械与物理所

利用新型实用的晶体材料V∶YAG作为被动调Q元件,实现了激光二极管泵浦Nd∶YVO4的1.34μm激光谱线调Q运转.研究了饱和吸收体小信号透过率对激光稳定性的影响,得出使用小信号透过率T0小的V∶YAG可使激光脉冲能量和重复频率稳定的结论.在1... 详细信息

利用新型实用的晶体材料V∶YAG作为被动调Q元件,实现了激光二极管泵浦Nd∶YVO4的1.34μm激光谱线调Q运转.研究了饱和吸收体小信号透过率对激光稳定性的影响,得出使用小信号透过率T0小的V∶YAG可使激光脉冲能量和重复频率稳定的结论.在1.6W的泵浦条件下,T0为96%、89%和85%时,4h脉冲能量和重复频率稳定性分别为15%、10%和5%.使用T0为85%的V∶YAG,获得了平均功率输出功率96mW,脉宽8.8ns,重复频率25kHz,峰值功率436W,脉冲能量3.84μJ的实验结果.

关键词：饱和吸收体被动调Q V:YAG Nd:YVO4 1.34μm

在线全文

学校读者我要写书评

暂无评论

大跨度PC梁式桥下挠机理分析及钢束配置

辽宁工程技术大学学报（自然科学版） 2016年第10期35卷 1095-1099页

作者：薛兴伟包龙生沈阳建筑大学交通工程学院辽宁沈阳110168

针对悬臂施工PC梁桥施工过程中恒载和预应力的弯矩叠加过程进行了分解和对比分析,揭示了悬臂施工PC梁式桥下挠机理,并总结恒载零弯矩法在挠度控制中的不足,据此提出新的钢束配置方法.研究结果表明:新的钢束配置方法采用"大悬臂多配束,... 详细信息

针对悬臂施工PC梁桥施工过程中恒载和预应力的弯矩叠加过程进行了分解和对比分析,揭示了悬臂施工PC梁式桥下挠机理,并总结恒载零弯矩法在挠度控制中的不足,据此提出新的钢束配置方法.研究结果表明:新的钢束配置方法采用"大悬臂多配束,小悬臂少配束"的钢束配置形式,能保证大部分节段预应力弯矩可以抵消恒载弯矩,又能达到优于恒载零弯矩法控制跨中挠度的目的;将该法分别应用于主跨70 m刚构桥和主跨168 m连续梁桥,较原设计方案跨中挠度均明显改善.

关键词：大跨度PC梁式桥钢束配置恒载零弯矩法挠度控制下挠开裂

在线全文

学校读者我要写书评

暂无评论

聚乳酸织物的增深染色工艺

毛纺科技 2024年第1期52卷 24-31页

作者：薛孟芳张京彬武飞张子超王翊国家先进印染技术创新中心山东泰安271000 山东中康国创先进印染技术研究院有限公司山东泰安271000

针对聚乳酸纤维染深性较差的问题,研究了聚乳酸纤维玻璃化转变温度、染液pH值、载体用量对染色深度的影响。针对聚乳酸纤维无专用染料的现状,对安诺可隆PUD系列、菲诺AC系列和龙盛UN SE系列进行了染色提升力测试,其中龙盛UN SE系列分散... 详细信息

针对聚乳酸纤维染深性较差的问题,研究了聚乳酸纤维玻璃化转变温度、染液pH值、载体用量对染色深度的影响。针对聚乳酸纤维无专用染料的现状,对安诺可隆PUD系列、菲诺AC系列和龙盛UN SE系列进行了染色提升力测试,其中龙盛UN SE系列分散染料应用于聚乳酸织物的染深性最好,且耐皂洗色牢度和耐汗渍色牢度均在4级以上。安诺可隆PUD系列染色提升力最差,菲诺AC系列染色提升力较好,但织物色牢度较差。载体对部分染料的染色提升力有提升作用。可提高聚乳酸纤维染深性的染色工艺为:110℃下定形60 s,使用醋酸+醋酸钠调节染液pH值为4.5左右,浴比为1∶10,室温入染,以1℃/min升温至70℃时保温10 min,再以1℃/min升温至105℃保温40 min,于60℃下还原清洗15 min。

关键词：聚乳酸织物染深性定形温度染料筛选染液条件

LD泵浦Cr∶YAG被动调Q556nm黄光激光器

在线全文

学校读者我要写书评

暂无评论

光子学报 2005年第11期34卷 1601-1604页

作者：贾富强郑权薛庆华卜轶坤钱龙生中国科学院长春光学精密机械与物理研究所

通过对谐振腔镜镀制合理的激光薄膜,成功实现了LD泵浦Nd∶YAG1.112μm激光谱线的运转.利用LBO腔内倍频Nd∶YAG/Cr∶YAG结构获得了高重复频率被动调Q556nm全固态黄光激光器,在注入泵浦功率为1.6W时,得到平均功率51mW,脉冲宽度48ns,重复频... 详细信息

通过对谐振腔镜镀制合理的激光薄膜,成功实现了LD泵浦Nd∶YAG1.112μm激光谱线的运转.利用LBO腔内倍频Nd∶YAG/Cr∶YAG结构获得了高重复频率被动调Q556nm全固态黄光激光器,在注入泵浦功率为1.6W时,得到平均功率51mW,脉冲宽度48ns,重复频率8.9kHz,峰值功率高达119W的脉冲黄光输出.

关键词： LD泵浦被动调Q 黄光激光器 556 nm