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A Method for Rapidly Determining the Optimal Distribution Locations of GNSS Stations for Orbit and ERP Measurement Based on Map Grid Zooming and Genetic Algorithm

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Computer Modeling in Engineering & Sciences 2018年第12期117卷 509-525页

作者： Qianxin Wang chao hu Ya Mao NASG Key Laboratory of Land Environment and Disaster Monitoring China University of Mining and TechnologyXuzhou221116China School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou221116China Mathematical and Geospatial Sciences RMIT UniversityMelbourne 3001Australia.

Designing the optimal distribution of Global Navigation Satellite System(GNSS)ground stations is crucial for determining the satellite orbit,satellite clock and Earth Rotation Parameters(ERP)at a desired precision using a limited number of *** this work,a new criterion for the optimal GNSS station distribution for orbit and ERP determination is proposed,named the minimum Orbit and ERP Dilution of Precision Factor(OEDOP)*** quickly identify the specific station locations for the optimal station distribution on a map,a method for the rapid determination of the selected station locations is developed,which is based on the map grid zooming and heuristic *** the minimum OEDOP criterion and the proposed method for the rapid determination of optimal station locations,an optimal or near-optimal station distribution scheme for 17 newly built BeiDou Navigation Satellite System(BDS)global tracking stations is *** verify the proposed criterion and method,real GNSS data are *** results show that the minimum OEDOP criterion is valid,as the smaller the value of OEDOP,the better the precision of the satellite orbit and ERP *** to the exhaustive method,the proposed method significantly improves the computational efficiency of the optimal station location *** the case of 3 newly built stations,the computational efficiency of the proposed method is 35 times greater than that of the exhaustive *** the number of stations increases,the improvement in the computational efficiency becomes increasingly obvious.

关键词： Global Navigation Satellite System(GNSS) optimal distribution of station network map grid zooming genetic algorithm.

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锅炉炉内汽水爆炸冲击波及爆炸效应评价研究

工业锅炉 2024年第3期 25-31,34页

作者：汪杰胡超林欣严祯荣上海工业锅炉研究所有限公司上海201114 上海工程技术大学机械与汽车工程学院上海201620 机械工业锅炉低碳化技术重点实验室上海201620

为合理地估算锅炉汽水爆炸冲击波的能量及破坏效应,首先对锅炉汽水爆炸的理论进行研究,主要包括锅炉汽水爆炸的过程与能量、TNT当量法、TNO多能法以及爆炸破坏评价准则,接着就某高温高压循环流化床锅炉水冷壁爆管引发炉内汽水爆炸事故... 详细信息

为合理地估算锅炉汽水爆炸冲击波的能量及破坏效应,首先对锅炉汽水爆炸的理论进行研究,主要包括锅炉汽水爆炸的过程与能量、TNT当量法、TNO多能法以及爆炸破坏评价准则,接着就某高温高压循环流化床锅炉水冷壁爆管引发炉内汽水爆炸事故进行计算分析,经计算,汽水爆炸总能量为150822.1 kJ,其中饱和蒸汽爆破能量占饱和水的比例α为10.5%,不能按照一般处理进行忽略;在TNT当量法中,汽水爆炸冲击波的峰值超压Δpmax=0.204 MPa,依据超压准则评价其破坏效应时,得到近场超压偏大的结论;在TNO多能法中,汽水爆炸的DN值为4.036×10~7 Pa2·s,依据超压-冲量准则评价其破坏效应与实际情况相符。TNT当量法容易高估近场处的超压,因此在估算锅炉炉内汽水爆炸破坏效应时,优先选用TNO多能法结合超压-冲量准则的方法,其结果更为准确。该研究成果对锅炉炉内汽水爆炸事故的预防、认定、诊断分析提供了理论计算依据和数据支撑,对锅炉实际工程项目中安全风险的辨识和评估有着重要的意义,同时为运行中降低炉内发生汽水爆炸的风险给出了运行管理建议。

关键词：锅炉汽水爆炸 TNT当量法 TNO多能法超压准则超压-冲量准则

Characteristics on Hydro-mechanical Transmission in Power Shift Process

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Chinese Journal of Mechanical Engineering 2009年第1期22卷 50-56页

作者： hu Jibin WEI chao YUAN Shihua JING Chongbo National Key Laboratory of Vehicular Transmission Beijing Institute of Technology Beijing 100081 China

To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmission, this paper explores the feasibility of shift without power interruption. With the four models concerning displacement ratio, rotational speed, rotational torque and power at ideal shift point, the characteristics on power shift in different running conditions are analyzed, and the rules of power shift are revealed. The theoretical analysis and test results show that the hydro-mechanical transmission can shift without power interruption in different running conditions. Furthermore, there exists an ideal shift point in theory, at which point the cycle power in hydro-mechanical transmission can＇t be generated, and the impact on the system can be reduced to the minimum. However, if before or after this ideal shift point, a cycle power can be generated.

关键词： stepless transmission hydro-mechanical transmission power shift

Wave localization in randomly disordered periodic layered piezoelectric structures

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Acta Mechanica Sinica 2006年第6期22卷 559-567页

作者： Fengming Li Yuesheng Wang chao hu Wenhu huang Department of Aerospace Science and Mechanics Harbin Institute of Technology Harbin 150001 China Institute of Engineering Mechanics Beijing Jiaotong University Beijing 100044 China School of Aerospace Engineering and Mechanics TongJi University Shanghai 200092 China Department of Aerospace Engineering and Mechanics Harbin Institute of Technology Harbin 150001 China

Considering the mechnoelectrical coupling, the localization of SH-waves in disordered periodic layered piezoelectric structures is studied. The waves propagating in directions normal and tangential to the layers are considered. The transfer matrices between two consecutive unit cells are obtained according to the continuity conditions. The expressions of localization factor and localization length in the disordered periodic structures are presented. For the disordered periodic piezoelectric structures, the numerical results of localization factor and localization length are presented and discussed. It can be seen from the results that the frequency passbands and stopbands appear for the ordered periodic structures and the wave localization phenomenon occurs in the disordered periodic ones, and the larger the coefficient of variation is, the greater the degree of wave localization is. The widths of stopbands in the ordered periodic structures are very narrow when the properties of the consecutive piezoelectric materials are similar and the intervals of stopbands become broader when a certain material parameter has large changes. For the wave propagating in the direction normal to the layers the localization length has less dependence on the frequency, but for the wave propagating in the direction tangential to the layers the localization length is strongly dependent on the frequency.

关键词： Disordered periodic layered piezoelectric structures Transfer matrix Lyapunov exponent Localization factor Localization length

A combined continuous-discontinuous approach for failure process of quasi-brittle materials

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Science China(Technological Sciences) 2014年第3期57卷 550-559页

作者： CHANG XiaoLin hu chao ZHOU Wei MA Gang ZHANG chao State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

Rock,concrete and other geo-materials,due to the presence of microstructural inhomogeneity,their fracture processes and damage characteristics are associated with the distribution of micro-cracks contained in the *** this study,by introducing a cohesive zone model based on fracture mechanics into the framework of deformable discrete element method,a continuous-discontinuous coupling analysis approach for simulating the fracture of quasi-brittle materials is *** cohesive interface elements are inserted into certain engineering or research *** is assumed that damage and fracture occur only in the interface elements,while bulk material is modeled to be *** Mohr-Coulomb criterion with tension cut-off is adopted as the damage initiation criterion,and a scalar damage variable representing damage in the material is used to describe the rate at which the material stiffness is *** are simulated explicitly by the failure of the interface *** simulations are performed in order to validate the suggested *** applications are also *** results show that this method provides a simple but effective tool for the simulation of crack initiation and propagation,and it can reflect the whole process of quasi-brittle materials from small deformation to large deformation and failure.

关键词： quasi-brittle materials deformable discrete elements cohesive zone model crack propagation

Design and implementation of a novel enterprise network defense system by maneuvering multi-dimensional network properties

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Frontiers of Information Technology & Electronic Engineering 2019年第2期20卷 238-252页

作者： Yang CHEN Hong-chao hu Guo-zhen CHENG National Digital Switching System Engineering & Technological R&D Center

Although the perimeter security model works well enough when all internal hosts are credible, it is becoming increasingly difficult to enforce as companies adopt mobile and cloud technologies, i.e., the rise of bring your own device(BYOD). It is observed that advanced targeted cyber-attacks usually follow a cyber kill chain;for instance, advanced targeted attacks often rely on network scanning techniques to gather information about potential targets. In response to this attack method, we propose a novel approach, i.e., an "isolating and dynamic"cyber defense, which cuts these potential chains to reduce the cumulative availability of the gathered ***, we build a zero-trust network environment through network isolation, and then multiple network properties are maneuvered so that the host characteristics and locations needed to identify vulnerabilities cannot be ***, we propose a software-defined proactive cyber defense solution(SPD) for enterprise networks and design a general framework to strategically maneuver the IP address, network port, domain name, and path, while limiting the performance impact on the benign network user. Third, we implement our SPD proof-of-concept system over a software-defined network controller(OpenDaylight). Finally, we build an experimental platform to verify the system's ability to prevent scanning, eavesdropping, and denial-of-service attacks. The results suggest that our system can significantly reduce the availability of network reconnaissance scan information, block network eavesdropping, and sharply increase the cost of cyber-attacks.

关键词： Intranet defense Software-defined network Multi-dimensional maneuvering

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一种顾及参数稀疏的GNSS瞬时钟差模型

大地测量与地球动力学 2024年第3期44卷 263-266,320页

作者：周圣淇王中元胡超王瑞光姚雪燕中国矿业大学环境与测绘学院江苏省221116 安徽理工大学空间信息与测绘工程学院安徽省232001

提出一种顾及参数稀疏的GNSS瞬时钟差模型构建算法,该算法通过在最小二乘多项式拟合中附加L 1范数项(Lasso)进行约束,并采用滑动建模的方式拟合钟差模型,即滑动Lasso拟合法。使用GFZ 300 s钟差产品作为训练数据,通过10折交叉验证获得正... 详细信息

提出一种顾及参数稀疏的GNSS瞬时钟差模型构建算法,该算法通过在最小二乘多项式拟合中附加L 1范数项(Lasso)进行约束,并采用滑动建模的方式拟合钟差模型,即滑动Lasso拟合法。使用GFZ 300 s钟差产品作为训练数据,通过10折交叉验证获得正则化参数,建立钟差模型,并与常用的钟差建模加密算法进行卫星钟差拟合精度与PPP定位精度对比。实验结果表明,滑动Lasso拟合法在进行钟差拟合建模时,对于局部钟差数据中出现跳变过大的钟差值,可以有效消除其在拟合过程中对模型造成的影响,防止模型过拟合,进而提高钟差模型的拟合精度与PPP定位精度。

关键词： Lasso 交叉验证稀疏模型钟差建模滑动式

点火位置对甲烷/空气预混爆炸特性影响的数值模拟研究

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爆破 2024年第1期41卷 186-195页

作者：王金贵梁志星胡强强朱杭钦胡超魏林慧福州大学环境与安全工程学院福州350116

密闭容器内预混气体爆炸非常复杂,为研究点火位置对甲烷/空气预混气体爆炸特性的影响,在初始压力为101 kPa和初始温度为300 K的环境下,开展1 m^(3)密闭球形爆炸容器中10 vol%甲烷浓度的中心点火爆炸实验,并使用Fluent数值模拟软件,采用... 详细信息

密闭容器内预混气体爆炸非常复杂,为研究点火位置对甲烷/空气预混气体爆炸特性的影响,在初始压力为101 kPa和初始温度为300 K的环境下,开展1 m^(3)密闭球形爆炸容器中10 vol%甲烷浓度的中心点火爆炸实验,并使用Fluent数值模拟软件,采用LES湍流模型和Zimont燃烧模型,研究不同点火位置(中心点火、0.5R点火、R点火)对容器内甲烷/空气预混气体爆炸特性的影响,包括火焰结构演化、爆炸温度、爆炸压力、爆炸压力上升速率。结果表明:(1)在中心、0.5R和R处点火时,火焰分别向四周膨胀直至容器壁面、轮廓由最初的“左薄右厚”逐渐转变为“左侧凸起的尖角”和在壁面处从“圆弧形”逐渐拉伸转变成“尖形”向左侧发展;(2)不同点火位置下温度场存在温度梯度,升温规律均由点火中心能量持续向外释放,温度不断积聚升高;(3)不同点火位置下爆炸压力变化趋势基本一致,由于壁面绝热,最终最大爆炸压力均稳定在766 kPa左右;(4)中心点火时最大爆炸压力上升速率最大,较0.5R点火和R处点火分别增大了94.5%和141.8%。

关键词：点火位置甲烷/空气预混气体火焰前锋大涡模拟密闭球形容器

石榴籽油的提取、营养组成及健康功效研究进展

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中国油料作物学报 2024年第1期46卷 208-220页

作者：胡子聪胡超凡李彦坡蒋巧俊李群和房翠兰温州市农业科学研究院食品科学研究所浙江温州325006 温州科技职业学院农业与生物技术学院浙江温州325006 温州市特色食品资源工程技术研究中心浙江温州325006 重庆市九龙坡区疾病预防控制中心重庆400039

石榴籽油是从石榴加工剩余物石榴籽中提取得到的一种功能性植物油,它具有抗氧化、抗炎症、抗肿瘤和预防心血管疾病等功效。本文从石榴籽油的提取方法、营养组成和健康功效等方面,对近年来国内外有关石榴籽油的研究结果进行了全面综述。... 详细信息

石榴籽油是从石榴加工剩余物石榴籽中提取得到的一种功能性植物油,它具有抗氧化、抗炎症、抗肿瘤和预防心血管疾病等功效。本文从石榴籽油的提取方法、营养组成和健康功效等方面,对近年来国内外有关石榴籽油的研究结果进行了全面综述。水酶法、溶剂萃取法、超临界流体萃取法和物理场辅助提取法对石榴籽油的得率和脂肪酸组成有明显的影响。尽管源于不同产地和不同提取方法的石榴籽油在脂肪酸组成上存在差异,但整体上来看,石榴籽油中不饱和脂肪酸占比达到88.57%~95.33%,其中以石榴酸为主(60.62%~81.40%),它是石榴籽油能够发挥一系列营养功效的主要活性成分。因此,石榴籽油是一种具有高营养价值和潜在利用价值的木本植物油,本文旨在为石榴籽油的进一步研究及其在食品、生物医药等领域的开发利用提供理论参考。

关键词：石榴籽油提取方法营养组成石榴酸健康功效活性机制