检索结果-南通市图书馆

Research on aiming methods for small sample size shooting tests of two-dimensional trajectory correction fuse

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第3期33卷 506-517页

作者： Chen Liang Qiang Shen zilong deng Hongyun Li Wenyang Pu Lingyun Tian Ziyang Lin School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction fuse *** impact point easily deviates from the target,and thus the correction result cannot be readily ***,the cost of shooting tests is considerably high to conduct many tests for data *** address this issue,this study proposes an aiming method for shooting tests based on small sample *** proposed method uses the Bootstrap method to expand the test data;repeatedly iterates and corrects the position of the simulated theoretical impact points through an improved compatibility test method;and dynamically adjusts the weight of the prior distribution of simulation results based on Kullback-Leibler divergence,which to some extent avoids the real data being"submerged"by the simulation data and achieves the fusion Bayesian estimation of the dispersion *** experimental results show that when the simulation accuracy is sufficiently high,the proposed method yields a smaller mean-square deviation in estimating the dispersion center and higher shooting accuracy than those of the three comparison methods,which is more conducive to reflecting the effect of the control algorithm and facilitating test personnel to iterate their proposed structures and algorithms.;in addition,this study provides a knowledge base for further comprehensive studies in the future.

关键词： Two-dimensional trajectory correction fuse Small sample size test Compatibility test KL divergence Fusion bayesian estimation

鸭式布局二维修正双旋弹角运动及转向响应特性分析

在线全文

学校读者我要写书评

暂无评论

兵工学报 2024年第6期45卷 1866-1876页

作者：李红云申强邓子龙北京理工大学机电学院北京100081 北京理工大学重庆创新中心重庆401120

为研究鸭式布局双旋弹受控状态下的动态响应规律,对弹丸角运动特性及转向响应特性进行理论分析。基于7自由度刚体弹道模型,求解弹丸受控状态下的攻角瞬态及稳态解析解,并推导弹丸瞬态及稳态转向响应解析表达式。研究控制指令更新周期、... 详细信息

为研究鸭式布局双旋弹受控状态下的动态响应规律,对弹丸角运动特性及转向响应特性进行理论分析。基于7自由度刚体弹道模型,求解弹丸受控状态下的攻角瞬态及稳态解析解,并推导弹丸瞬态及稳态转向响应解析表达式。研究控制指令更新周期、射角、转速及初速对转向响应特性的影响。研究结果表明:输入控制力方向对转向响应相移角影响较小;控制指令更新周期较短时,在弹道顶点相移角瞬态解与稳态解相差较大,采用瞬态解修正后弹丸横纵向耦合程度较低,随着指令更新周期的增大,转向响应相移角瞬态解逐渐趋于稳态解;相移角稳态解随转速增加而减小,随初速增加而增加。通过实验数据验证了理论的正确性。研究结果可为鸭式布局双旋弹二维修正控制系统分析设计提供理论依据。

关键词：二维弹道修正弹鸭式布局角运动特性转向响应特性瞬态响应

Melting heat transfer enhancement of a horizontal latent heat storage unit by fern-fractal fins

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第11期28卷 2857-2871页

作者： zilong deng Suchen Wu Hao Xu Yongping Chen Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Environmental Science and EngineeringSuzhou University of Science and TechnologySuzhou 215009China

The latent heat storage(LHS)technique is of crucial importance in chemical energy *** by multi-bifurcated fern leaves,a mimic fern-fractal fin is designed to improve the thermal energy charging *** paper develops a transient melting model of a rectangular LHS unit using fern-fractal fins,and their melting behaviors are compared with the conventional ***,a parametric optimization of fernfractal fins is conducted for maximizing the thermal efficiency based on the response surface method(RSM).The results indicate that the temperature uniformity is more superior and the melting duration is shorter for the fern-fractal LHS unit when compared with the conventional ***,the fern-fractal LHS device presents a slower heat storage rate during the initial conduction-dominated and early convection-dominated melting stages,while a prominent melting enhancement is achieved during the later melting *** shortest melting time is obtained based on the RSM technique when a fern-fractal fin with length ratio α=0.94 and branch angle θ=54.7°is *** with a conventional fin,the averaged heat storage rate increases by 88.3%,and the total melting time is declined by 40.3%for an optimized fern-fractal fin.

关键词： Multiscale Fractal Numerical simulation Heat storage Optimization

Cutting performance of micro-textured PCBN tool

在线全文

学校读者我要写书评

暂无评论

Nanotechnology and Precision Engineering 2021年第2期4卷 25-32页

作者： Lin Fan zilong deng Xingjun Gao Yan He School of Mechanical Engineering Liaoning Perochmical University Fushun 113001china

To study the efect of micro-texture on the cutting performance of polyrystalline cubic boron nitide(PCBN)tools,five types of micro-textures(circular pits,eliptical grooves,transverse grooves,composite grooves,and wavy grooves)were applied to the rake surface of PCBN tools by an optical fber laser marking *** a combination of three dimensional cutting simulations and experiments,the influences of micro-texture on chip-tool contact area,cutting force,chip morphology,shear angle,and surface roughness during the cuting process were *** results indicated that the chip--tool contact area and cutting force of both non-textured and micro textured tools increased with increasing cutting speed,while the shear angle decreased with increasing cutting *** chip-tool contact area and cutting force of the five types of micro-textured tools were smaller than those of the non textured tool The chip-tool contact area and cutting force obtained by the wavy-groove micro textured tool were the *** chip radius produced by the five types of micro-textured tools was smaller than that produced by the non-textured tool,and the chip morphology was more *** transverse-groove micro-textured tool had a better chip breaking *** chip rnadius generated by the lliptical groove micro textured tool was 0.96 cm,while that generated by the wavy-groove tool varied from 0.55 cm to 1.26 *** presence of a micro-texture reduced the surface roughness of the workpiece by 11.73%-56.7%.Under the same cutting conditions,the five types of micro-textured tools gave a smaller chip--tool contact area,cutting force,chip radius,and surface roughness and a larger shear angle than the non-textured *** addition,the elliptical groove and wavy-groove micro-textured tools had better cuting performance.

关键词： Micro-textured tool Chip tool contact area Cutting force Chip radius

Design of large-displacement asymmetric piezoelectric microgripper based on flexible mechanisms

在线全文

学校读者我要写书评

暂无评论

Nanotechnology and Precision Engineering 2019年第4期2卷 188-193页

作者： Xiaodong Chen Siya Hu zilong deng Jinhai Gao Xingjun Gao College of Mechanical Engineering Liaoning University of Petroleum and Chemical TechnologyFushun 113001China College of Mechanical Engineering and Automation Northeast UniversityShenyang 110000China

The output displacement of the traditional symmetrical microgripper is large,but its micro-components or parts are easily damaged due to the uneven force exerted on the left and right jaws of the *** output force of the traditional asymmetric microgripper is ***,its output displacement is small,typically half the output displacement of the symmetric *** solve these problems,in this study,we designed a large-displacement asymmetric ***,we calculated the relationship between the theoretical input and output variables based on their geometric ***,we analyzed the performance of the microgripper using finite element ***,we used a piezoelectric actuator as the input driver of the *** errors associated with the theoretical and simulated output displacements were 7.05%and 9.24%,*** 150 V of driving voltage,the maximum output displacement was 224μm,and the actual magnificationwas 11.2 *** can be gripped in parallel and stably,which confirms the validity of the design.

关键词： Microgripper Asymmetry Piezoelectric drive Experimental verification

基于ADAMS变胞升降机构构态变换动力学仿真分析

在线全文

学校读者我要写书评

暂无评论

辽宁石油化工大学学报 2024年第4期44卷 60-66页

作者：周怀堂邓子龙耿铁民何艳辽宁石油化工大学机械工程学院辽宁抚顺113001 抚顺石化工程建设有限公司辽宁抚顺113008

在地震等自然灾害发生时,道路上常常会出现大小碎石,而大小碎石影响抢险运输车的快速通行。在车辆底盘加装升降机构是解决这一问题的有效办法。然而,现有的升降机构升降方式较为单一,占用空间较大,不便安装在车辆下方。此外,还面临着不... 详细信息

在地震等自然灾害发生时,道路上常常会出现大小碎石,而大小碎石影响抢险运输车的快速通行。在车辆底盘加装升降机构是解决这一问题的有效办法。然而,现有的升降机构升降方式较为单一,占用空间较大,不便安装在车辆下方。此外,还面临着不能随不同的工况进行灵活升降的问题。为了解决这些问题,基于变胞机构原理设计了一种变胞升降机构;建立变胞升降机构的虚拟样机模型,利用ADAMS软件进行构态变换动力学仿真实验,研究了车辆在构态变换过程中的动力学特性。结果表明,该机构具有变拓扑构型和变自由度的特点,能够根据工况的不同,以不同的构态完成工作任务;针对不同大小的障碍物,该机构可进行一级或二级升高,实现快速越障;该机构具有优异的可行性和稳定性。

关键词：变胞机构升降机构构态变换动力学

Design of a flexible piezoelectric microgripper based on combined amplification principles

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Nanotechnology and Precision Engineering 2019年第3期2卷 138-143页

作者： Xiaodong Chen zilong deng Siya Hu Jinhai Gao Xingjun Gao College of Mechanical Engineering Liaoning University of Petroleum and Chemical TechnologyFushun 113001China College of Mechanical Engineering and Automation Northeast UniversityShenyang 110000China

Aiming to address the problem of the low amplification ratio of traditional microgrippers,a two-stage microgripper based on the principle of combined amplification was designed with a high amplification ratio and large displacement,using a simple and compact *** relationship between theoretical input variables and output variables were first calculated by a projection ***,the performance of the microgripper was analyzed by finite element analysis(FEA).Finally,the accuracy of the theoretical calculation and FEA was verified *** results show that the microgripper has high magnification and can be gripped in parallel,with self-adaptability for many irregular shaped micro *** actual magnification was 23.2×,which is greater than similar products.

关键词： Microgripper High magnification Projection theorem FEA Experimental verification

Bubble breakup in a microfluidic T-junction

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2016年第10期61卷 811-824页

作者： Xiangdong Liu Chengbin Zhang Wei Yu zilong deng Yongping Chen School of Hydraulic Energy and Power Engineering Yangzhou University Yangzhou 225127 China Key Laboratory of Energy Thermal Conversion and Control ofMinistry of Education School of Energy and EnvironmentSoutheast University Nanjing 210096 China

We conduct a computational fluid dynamics simulation to investigate the behaviors of bubble breakup in a microfluidic T-junction using volume-of-fluid method to represent the interface. The evolution of bubble mor- phology and the distributions of velocity and pressure in flow field are analyzed, and the effect of width ratio between main channel and branch on the bubble mor- phology are evaluated. The results indicate that, the ＂tun- nel＂ breakup, obstructed breakup, combined breakup and non-breakup are observed during the bubble flows through the T-junctions under different condition. The whole bub- ble breakup process undergoes the extension, squeeze and pinch-off stages, while the non-breakup process experi- ences extension and pushing stages. We find that, in the squeeze stage, a local vortex flow forms at the front edge of the bubble for the ＂tunnel＂ breakup while the velocity inside the bubble is of a parabolic distribution for the obstructed breakup. Irrespective of non-breakup regimes, there is a sudden pressure drop occurring at the gas-liquid interface of the bubble in the squeeze stage, and the pres- sure drop at the front interface is far larger than that at the depression region. The transition of the bubble breakup regime through the T-junction occurs with an increase in width ratio of main channel to the branch, which sequen- tially experiences the non-breakup regime, ＂tunnel＂ breakup regime and obstructed breakup regime. The flow regime diagrams are plotted with a power-law correlation to distinguish the bubble/droplet breakup and non-breakup regimes, which also characterize the difference between bubble and droplet breakup through a T-junction.

关键词： Bubble flow Breakup - T-junction Microfluidic

Nitrogen-doped iron for selective catalytic reduction of nitrate to dinitrogen

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2020年第11期65卷 926-933,M0004页

作者： Jing Wang Lan Ling zilong deng⇑ Wei-xian Zhang State Key Laboratory for Pollution Control School of Environmental Science and EngineeringShanghai Institute of Pollution Control and Ecological SecurityTongji UniversityShanghai 200092China

Nitrate is the leading cause of eutrophication worldwide and is one of the most challenging pollutants for restoration of polluted surface waters such as lakes, rivers and reservoirs. We report herein a new architecture of iron nanoparticles for high-efficiency denitrification by selective reduction of nitrate (NO3-) to dinitrogen (N2). The iron nanoparticles are doped with nitrogen (FeN) and encapsulated within a thin layer of nitride-carbon (NC). The nanoparticles have high pyrrolic N content (17.4 at.%) and large specific surface area (2040 m2/g). Laboratory experiments demonstrated high N2selectivity (91%) and nitrate removal capacity (6004 mg N/g Fe) for treatment of nitrate-containing water. This iron-based nanomaterial overcomes shortcomings of conventional catalysts by eliminating the use of precious and toxic heavy metals (e.g., Pd, Pt, Cu, Ni) and minimizing the generation of undesirable byproducts (e.g., ammonia) from the reactions with nanoscale zero-valent iron (n ZVI). The multiple electron transfers process from NO3- to N2can be fine-tuned by adjusting the NC shell thickness. Superior electrocatalytic perfor- mance, low cost and minimal environmental impact of the iron-derived nanocatalyst offer promising prospects for water purification, waste treatment and environmental remediation.

关键词： Nitrogen-doped iron(FeN) Core-shell structure Electrocatalytic denitrification N2 selectivity nZVI