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A direct position determination method with combined TdOA and FdOA based on particle filter

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Chinese Journal of Aeronautics 2018年第1期31卷 161-168页

作者： Zhiyu LU Bin ba Jianhui WANG Wenchao LI daming WANG China National digital Switching System Engineering & Technological R&d Cente Zhengzhou 450000 China Jiuquan Satellite Launch Center Jiuquan 735000 China

The localization of a stationary transmitter using moving receivers is considered. The original direct Position determination （dPd） methods, with combined Time difference of Arrival （TdOA） and Frequency difference of Arrival （FdOA）, do not perform well under low Signal-to-Noise Ratio （SNR）, and worse still, the computation cost is difficult to accept when the computational capabilities are limited. To get better positioning performance, we present a new dPd algorithm that proves to be more computationally efficient and more precise for weak signals than the conventional approach. The algorithm partitions the signal received with the same receiver into multiple non-overlapping short-time signal segments, and then uses the TdOA, the FdOA and the coherency among the short-time signals to locate the target. The fast maximum likelihood estimation, one iterative method based on particle filter, is designed to solve the problem of high computation load. A secondary but important result is a derivation of closed-form expressions of the Cramer-Rao Lower Bound （CRLB）. The simulation results show that the algorithm proposed in this paper outperforms the traditional dPd algorithms with more accurate results and higher computational efficiency, and especially at low SNR, it is more close to the CRLB.

关键词： direct position determination Cramer-Rao lower bound Frequency difference of arrival Time difference of arrival Particle filter

Nonlinear Mathematical Modeling and Sensitivity Analysis of Hydraulic drive Unit

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 999-1011页

作者： KONG Xiangdong YU Bin QUAN Lingxiao ba Kaixian WU Liujie National Engineering Research Center for Local Joint of Advanced Manufacturing Technology and Equipment Yanshan University Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University School of Mechanical Engineering Yanshan University

The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity index

关键词： nonlinear mathematical model hydraulic drive unit valve-controlled symmetrical cylinder sensitivity analysis sensitivity index

我国油气工程技术装备智能化和智能制造的探索与实践

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石油机械 2024年第6期52卷 1-11页

作者：贺会群张行巴莎于楠张慧筠王逸达汪洁中国石油集团工程技术研究院有限公司中国石油大学(北京)机械与储运工程学院中国石油和石油化工设备工业协会

经过数十年发展,我国油气工程技术装备整体水平步入国际先进行列,实现了从初期的机械化到自动化和信息化,以及目前部分数字化与智能化的跨越。分析和描述了万米特深井钻机、“一键式”自动化钻机、智能钻井系统、5G加持的压裂机组、自... 详细信息

经过数十年发展,我国油气工程技术装备整体水平步入国际先进行列,实现了从初期的机械化到自动化和信息化,以及目前部分数字化与智能化的跨越。分析和描述了万米特深井钻机、“一键式”自动化钻机、智能钻井系统、5G加持的压裂机组、自动化连续管装备、连续管作业智能支持中心、智能导向钻井控制系统、万米自动化顶驱、智能钻杆等国内典型油气工程技术装备的关键技术特征和智能化水平。认为国内油气工程技术装备的智能化依然以第一代“自动化”、第二代“数字化+网络化”为主,要全面实现第三代智能化,任重道远。论述了智能制造的内涵、国内油气工程技术装备智能制造的发展概况,认为国内油气工程技术装备的智能制造取得了长足进步,尤其是在应用层面已经跟上了全球发展步伐,在某些方面形成了中国特色。以连续管作业装备为制造对象,构建了“基于工业互联网的连续管装备智能制造整体解决框架”,剖析了智能工厂、制造知识、精益生产、智能装备、工业软件等关键要素。研究结果可为全面实现油气工程技术装备智能制造提供参考。

关键词：油气工程技术装备智能化智能制造万米深井国内发展典型案例

Multi-hazard disaster scenario method and emergency management for urban resilience by integrating experiment-simulation-field data

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Journal of Safety Science and Resilience 2021年第2期2卷 77-89页

作者： Rui ba Qing deng Yi Liu Rui Yang Hui Zhang Institute of Public Safety Research Tsinghua UniversityBeijing 100084China

due to the frequent occurrence of multi-hazard disasters worldwide in recent years,effective multi-hazard sce-nario analysis is imperative for disaster rescue and emergency *** response procedure for different single hazards were investigated and formulated ***,the investigations of disaster scenario rarely systematically address the entire development and response process of multi-hazards,including the coupling mechanisms,evolution dynamics,scenario assessment and emergency *** this end,this paper presents our methodology of multi-hazard disaster scenario that integrates experiment-simulation-field data,focusing on three dimensions consisting of multi-hazard coupling,structures and systems,and emergency *** newly proposed scenario method mainly comprises three aspects:experiments and simulations,multi-hazard field investigation,scenario analysis and ***,in order to study the large-scale,high-intensity and multi-hazard coupling effects,we carried out reduced-scale experiments and field measurement experiments to develop experimental similarity theory and prototype simulations of *** addition,a variety of field rescue and survey equipment,such as robots,Unmanned Aerial Vehicle(UAV),and Virtual Reality/Augmented Reality(VR/AR)technologies were utilized to acquire real-time data of multi-hazard ***,we also examine the mechanism and framework of multi-hazard scenarios to formulate the detailed procedures of man-agement and *** are incorporated with the experiments,simulations,field data and models to con-struct a new scenario *** proposed scenario method was applied in a case study of the coupled wind and snow multi-hazard to verify its *** new method contributes to the disaster relief,decision-making and emergency management for multi-hazard disaster to improve the urban resilience.

关键词： Multi-hazard disaster Scenario Resilience Emergency management

Synergistically enhancing cycleability and rate performance of sodium titanate nanowire anode via hydrogenation and carbon coating for advanced sodium ion batteries

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Rare Metals 2022年第12期41卷 4075-4085页

作者： de-Liang ba Wei-Hua Zhu Yuan-Yuan Li Jin-Ping Liu School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China School of Chemistry Chemical Engineering and Life ScienceState Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingWuhan University of TechnologyWuhan 430070China State Center for International Cooperation on designer Low-Carbon and Environmental Materials and School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

Layered alkali-metal titanate materials are considered as attractive anodes for sodium ion batteries due to their favorable safety and low ***,their practical implementation faces major challenges of low electronic conductivity and inevitable volume variation during Na^(+)intercalation and de-intercalation,which are generally difficult to conquer by a single modification ***,a synergistic ally enhancing strategy to promote the electrochemical performance of Na_(2)Ti_(2)O_(5)nanowire array anode via simultaneous hydrogenation and carbon coating is *** leads to partially reduced titanium;together with conductive carbon layer,it endows Na_(2)Ti_(2)O_(5)with fast electron transport and structural *** resulting H-Na_(2)Ti_(2)O_(5)@C anode exhibits enhanced rate capability(8.0C,165 mAh·g^(-1))and stable cycle performance up to 1000 times in sodium-ion half-cells(the capacity of H-Na_(2)Ti_(2)O_(5)without carbon fades drastically after only 100 cycles).In addition,a newcoupling full cell is further designed with graphene hybridized high-voltage Na_(3)(VO_(0.5))_(2)(PO4)_(2)F_(2)as cathode,capable of delivering a high specific energy density of 212.1 Wh·kg^(-1)(based on the mass of both anode and cathode)and good rate and cycling *** work may offer inspiration for synergistic optimization of electrode materials for advanced electrochemical energy storage devices.

关键词： Sodium ion batteries(SIBs) Na2Ti2O5 nanowire Hydrogenation Carbon coating Enhanced performance

磁共振IdEAL-IQ和IVIM-dWI在脊柱转移瘤和骨髓瘤鉴别中的价值

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临床放射学杂志 2024年第7期43卷 1175-1180页

作者：王帅娜巴义文闫瑞芳周凤梅李政韩东明新乡医学院第一附属医院磁共振科卫辉453100 新乡医学院第一附属医院骨科卫辉453100

目的探索磁共振水脂分离成像(IdEAL-IQ)和体素内不相干运动成像(IVIM)在脊柱转移瘤和骨髓瘤鉴别中的价值。方法共45例脊柱转移瘤和26例骨髓瘤患者接受了IdEAL-IQ和IVIM扫描,分别测量并对比脊柱转移瘤组与骨髓瘤组间脂肪分数(FF)、R_(2)^... 详细信息

目的探索磁共振水脂分离成像(IdEAL-IQ)和体素内不相干运动成像(IVIM)在脊柱转移瘤和骨髓瘤鉴别中的价值。方法共45例脊柱转移瘤和26例骨髓瘤患者接受了IdEAL-IQ和IVIM扫描,分别测量并对比脊柱转移瘤组与骨髓瘤组间脂肪分数(FF)、R_(2)^(*)、标准表观扩散系数(AdC_(stand))、真性扩散系数(d)、假性扩散系数(d^(*))、灌注分数(f)、分布扩散系数(ddC)和扩散异质性指数(α)值的差异。采用逻辑回归(LR)分析寻找独立预测因子,受试者工作特征曲线(ROC)曲线下面积(AUC)和deLong检验分别被用于评估各参数诊断效能以及不同参数AUC间的差异。结果骨髓瘤组的FF、R_(2)^(*)、AdC_(stand)、d、ddC和α值均低于转移瘤组,d^(*)值高于转移瘤组(P均d和α是脊柱转移瘤和骨髓瘤鉴别的独立预测因子,四者结合的AUC为0.976,敏感度为91.11%,特异度为92.31%。deLong分析显示,AUC(FF+R_(2)^(*)+d+α)与AUC(FF)、AUC(R_(2)^(*))、AUC(AdC_(stand))、AUC(d)、AUC(d^(*))、AUC(ddC)、AUC(α)之间的差异均有统计学意义(Z=4.362、3.766、3.119、3.195、4.389、2.911、2.781,Pd和α是脊柱转移瘤和骨髓瘤鉴别的独立预测因子,将其进行联合相较单一参数其能更好地对上述疾病进行鉴别。

关键词：脊柱转移瘤骨髓瘤水脂分离技术体素内不相干运动成像

三轴形变核^(131)ba中的奇异集体激发模式

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物理学报 2024年第11期73卷 89-100页

作者：韦锐周厚兵王思成丁兵强赟华贾晨旭陈红星郭松 C.M.Petrache d.Mengoni A.Astier E.dupont 吕冰锋 d.bazzacco A.Boso A.Goasduff F.Recchia d.Testov F.Galtarossa G.Jaworski d.R.Napoli S.Riccetto M.Siciliano J.J.Valiente-dobon C.Andreoiu F.H.Garcia K.Ortner K.Whitmore A.Ataç-Nyberg T.Bäck B.Cederwall E.A.Lawrie I.Kuti d.Sohler T.Marchlewski J.Srebrny A.Tucholski 广西师范大学物理科学与技术学院桂林541004 广西核物理与核技术重点实验室桂林541004 中国科学院近代物理研究所兰州730000 中国科学院大学北京100049 巴黎萨克雷大学 CNRS/IN2P3IJCLab奥赛91405 帕多瓦大学物理和天文学系帕多瓦I-35131 意大利国家核物理研究所帕多瓦分部帕多瓦I-35131 意大利国家核物理研究所莱尼亚罗国家实验室莱尼亚罗(帕多瓦)I-35020 费拉拉大学理学与自然科学院费拉拉西蒙菲莎大学化学系本拿比BC V5A 1S6 皇家理工学院物理系斯德哥摩尔S-10691 国家研究基金会iThemba加速器科学实验室西萨默塞特7123 西开普大学物理与天文系贝尔维尔ZA-7535 HUN-REN原子核研究所德布勒森4001 华沙巴斯德拉大学重离子实验室华沙02-093

利用意大利Legnaro实验室串列静电加速器提供的65 MeV^(13)C束流与122Sn靶的熔合蒸发反应布居了^(131)ba的高自旋态,并搭建了新的能级纲图.新的能级纲图由15条转动带组成,包括三对手征双重带,其中两对正宇称手征带为赝自旋-手征四重带.... 详细信息

利用意大利Legnaro实验室串列静电加速器提供的65 MeV^(13)C束流与122Sn靶的熔合蒸发反应布居了^(131)ba的高自旋态,并搭建了新的能级纲图.新的能级纲图由15条转动带组成,包括三对手征双重带,其中两对正宇称手征带为赝自旋-手征四重带.正负宇称手征带通过一系列增强的E1跃迁连接,表明它们之间存在八极关联.在低自旋区域搭建了一条新的转动带,通过一系列γ跃迁向νh1_(1/2)晕带退激.这种能级结构与摇摆带相似,但基于现有的实验证据还难以将它确认为摇摆带,不能排除其他集体激发机制,如γ振动的影响.

关键词：高自旋态手征带赝自旋八极关联摇摆运动

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High-gain and low-distortion Brillouin amplification based on pump multi-frequency intensity modulation

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Chinese Physics B 2019年第2期28卷 277-282页

作者： Li-Wen Sheng de-Xin ba Zhi-Wei Lv National Key Laboratory of Science and Technology on Tunable Laser Harbin Institute of Technology

Using a pump with a multi-line spectrum to broaden the Brillouin gain bandwidth is an effective way to achieve lowdistortion amplification with high gain. Here, we theoretically and experimentally investigate the generation of a broadband Brillouin gain spectrum based on multi-frequency intensity modulation in an optical fiber. The arbitrary bandwidth of the Brillouin gain spectrum of stimulated Brillouin scattering(SBS) can be obtained as expected. In our experiment, a broadband Brillouin gain spectrum with a bandwidth of about 200 MHz is demonstrated. We also achieve a low-distortion amplification of a weak signal, whose maximum magnification is 65 d B for a-68-dBm input power signal.

关键词： Brillouin gain spectrum bandwidth intensity modulation low distortion amplification

Rethinking the urban resilience:Extension and connotation

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Journal of Safety Science and Resilience 2022年第4期3卷 398-403页

作者： Rui ba Chenyang Wang Luyao Kou Xiaojing Guo Hui Zhang School of National Security People’s Public Security University of ChinaBeijing100038China Institute of Public Safety Research Tsinghua UniversityBeijing100084China

In recent years,urban resilience has attracted increasing attention from researchers and managers from the international community at the national,regional,and urban *** multi-dimensional and cross-disciplinary investigations,campaigns,and outlines have significantly promoted the development goal of re-silience in cities ***,the existing definitions and interpretations of urban resilience still call for a more comprehensive,systematic,and exhaustive analysis as urbanization accelerates and the complex risks of various safety events *** this end,we rethink the extension and connotation of urban resilience based on a review and analysis of critical hotspots,realistic demand,and development trends.A conceptual classification with three aspects and three typical tiers of urban resilience is proposed,which further promotes a new definition and interpretation by incorporating the resilience extension of urban *** addition,the six-dimensional characteristics are extracted to furnish the urban resilience connotation,and four-stage improvement measures are introduced *** addition,the newly developed urban resilience is applied to a case analysis of a large-scale disaster,which demonstrates the necessity and significance of this *** new extension and connotation investigation will be helpful for the improvement and implementation of urban resilience,thereby guiding the construction of resilient cities.

关键词： Urban resilience Infrastructure Social units Complex systems