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Cost effective technologies for long range microwave wireless power transmission
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作者 CHOI Joon-Min KIM Dae-Kwan +3 位作者 PARK Durk-Jong YI Sang-Hwa KIM Dong-Min KO Dae-Ho 《中国空间科学技术(中英文)》 北大核心 2026年第1期122-134,共13页
Space-Based Solar Power(SBSP) presents a promising solution for achieving carbon neutrality and Renewable Electricity 100%(RE100) goals by offering a stable and continuous energy supply. However, its commercialization... Space-Based Solar Power(SBSP) presents a promising solution for achieving carbon neutrality and Renewable Electricity 100%(RE100) goals by offering a stable and continuous energy supply. However, its commercialization faces significant obstacles due to the technical challenges of long-distance microwave Wireless Power Transmission(WPT) from geostationary orbit. Even ground-based kilometer-scale WPT experiments remain difficult because of limited testing infrastructure, high costs, and strict electromagnetic wave regulations. Since the 1975 NASA-Raytheon experiment, which successfully recovered 30 kW of power over 1.55 km, there has been little progress in extending the transmission distance or increasing the retrieved power. This study proposes a cost-effective methodology for conducting long-range WPT experiments in constrained environments by utilizing existing infrastructure. A deep space antenna operating at 2.08 GHz with an output power of 2.3 kW and a gain of 55.3 dBi was used as the transmitter. Two test configurations were implemented: a 1.81 km ground-to-air test using an aerostat to elevate the receiver and a 1.82 km ground-to-ground test using a ladder truck positioned on a plateau. The rectenna consists of a lightweight 3×3 patch antenna array(0.9 m × 0.9 m), accompanied by a steering device and LED indicators to verify power reception. The aerostat-based test achieved a power density of 154.6 mW/m2, which corresponds to approximately 6.2% of the theoretical maximum. The performance gap is primarily attributed to near-field interference, detuning of the patch antenna, rectifier mismatch, and alignment issues. These limitations are expected to be mitigated through improved patch antenna fabrication, a transition from GaN to GaAs rectifiers optimized for lower input power, and the implementation of an automated alignment system. With these enhancements, the recovered power is expected to improve by approximately four to five times. The results demonstrate a practical and scalable framework for long-range WPT experiments under constrained conditions and provide key insights for advancing SBSP technology. 展开更多
关键词 wireless power transmission space-based solar power deep space antenna DSP KDSA KARI RECTENNA AEROSTAT
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基于动态Power迭代的大语言模型微调算法
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作者 匡豪 刘波 +2 位作者 李辉越 曾闰 段围 《计算机科学与探索》 北大核心 2026年第3期785-800,共16页
随着大语言模型在各领域的广泛应用,微调成为其适配特定任务的重要方法。当前主流的大模型微调方法主要分为部分微调和全量微调两种。部分微调虽能降低计算开销,但该方法仅更新大模型的少量参数,导致在复杂任务场景下,微调出的模型性能... 随着大语言模型在各领域的广泛应用,微调成为其适配特定任务的重要方法。当前主流的大模型微调方法主要分为部分微调和全量微调两种。部分微调虽能降低计算开销,但该方法仅更新大模型的少量参数,导致在复杂任务场景下,微调出的模型性能受限;虽然全量微调可以解决这一问题,但全量微调需要全面更新模型参数,从而导致微调时会存在计算资源需求高、微调时间长等问题。为解决全量微调存在的问题,提出一种基于动态Power迭代的梯度低秩投影算法(DPI-GLRP)。该方法基于秩一矩阵近似的思想,将大模型的权重矩阵在反向传播阶段产生的梯度矩阵分解为多个秩一矩阵,并通过Power迭代算法求解前r个特征向量以构成投影矩阵。该方法不仅解决了传统Power迭代只能获取单一最大特征向量的问题,还解决了以往研究中使用奇异值分解构建投影矩阵时间复杂度高、微调时间长的问题。对传统Power迭代算法进行研究发现,在特征值分布接近时,会出现收敛速度慢的问题。针对这一问题,提出一种动态Power迭代算法,该算法通过自适应调整迭代参数加快特征向量的计算效率,并从理论上证明提出的动态Power迭代算法的收敛效率比传统Power迭代要高。在LLaMA、Qwen等大模型上的实验表明,相较于LoRA等主流算法,DPI-GLRP算法能在保持或提升模型能力的同时,显著缩短微调时间,平均微调时间最多减少了80%。 展开更多
关键词 大语言模型 微调 梯度低秩投影 power迭代
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Microwave power transmission technologies for space solar power station
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作者 YANG Bo SHINOHARA Naoki 《中国空间科学技术(中英文)》 北大核心 2025年第2期1-14,共14页
The microwave wireless power transmission technologies for space solar power station are a crucial field in the international space sector,where various countries are competing in its development.This paper surveys th... The microwave wireless power transmission technologies for space solar power station are a crucial field in the international space sector,where various countries are competing in its development.This paper surveys the research experiments and development efforts related to space solar power stations and microwave wireless power transmission technologies worldwide.The objective is to assess the progress and current state of this technological foundation,determine the necessary focus for developing high-power microwave wireless power transmission technology,and provide clarity on the direction of future technology development in these areas.Finally,a distributed space solar power station plan that is immediately feasible is proposed. 展开更多
关键词 microwave power transmission space solar power station wireless power transfer microwave transmitter phased array rectenna array
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Multi-objective optimization of microwave power transmission system architecture with engineering consideration
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作者 DONG Shiwei SHINOHARA Naoki 《中国空间科学技术(中英文)》 北大核心 2025年第4期114-122,共9页
In the last decade,space solar power satellites(SSPSs)have been conceived to support net-zero carbon emissions and have attracted considerable attention.Electric energy is transmitted to the ground via a microwave pow... In the last decade,space solar power satellites(SSPSs)have been conceived to support net-zero carbon emissions and have attracted considerable attention.Electric energy is transmitted to the ground via a microwave power beam,a technology known as microwave power transmission(MPT).Due to the vast transmission distance of tens of thousands of kilometers,the power transmitting antenna array must span up to 1 kilometer in diameter.At the same time,the size of the rectifying array on the ground should extend over a few kilometers.This makes the MPT system of SSPSs significantly larger than the existing aerospace engineering system.To design and operate a rational MPT system,comprehensive optimization is required.Taking the space MPT system engineering into consideration,a novel multi-objective optimization function is proposed and further analyzed.The multi-objective optimization problem is modeled mathematically.Beam collection efficiency(BCE)is the primary factor,followed by the thermal management capability.Some tapers,designed to solve the conflict between BCE and the thermal problem,are reviewed.In addition to these two factors,rectenna design complexity is included as a functional factor in the optimization objective.Weight coefficients are assigned to these factors to prioritize them.Radiating planar arrays with different aperture illumination fields are studied,and their performances are compared using the multi-objective optimization function.Transmitting array size,rectifying array size,transmission distance,and transmitted power remaine constant in various cases,ensuring fair comparisons.The analysis results show that the proposed optimization function is effective in optimizing and selecting the MPT system architecture.It is also noted that the multi-objective optimization function can be expanded to include other factors in the future. 展开更多
关键词 space solar power satellite(SSPS) microwave power transmission(MPT) multi-objective function beam collection efficiency(BCE) system engineering
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基于Power BI的绿色供应链环境成本管理研究 被引量:5
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作者 潘富玲 符丽美 《财会通讯》 北大核心 2025年第2期169-176,共8页
一味追求经济利益而忽略环境因素将不利于企业实现绿色可持续发展目标,同时也与当前国家大力号召的绿色低碳转型产业方向相背离。传统末端治理方法会导致事后阶段环境成本的比重不断增加,进而使企业面临着巨大的双重压力即经济和环境污... 一味追求经济利益而忽略环境因素将不利于企业实现绿色可持续发展目标,同时也与当前国家大力号召的绿色低碳转型产业方向相背离。传统末端治理方法会导致事后阶段环境成本的比重不断增加,进而使企业面临着巨大的双重压力即经济和环境污染治理负担。如何有效提升公司的环境成本管理效率和效果成为环保机构、企业及社会各界关注的重点问题。企业环境成本产生于绿色供应链各环节之中,为进一步提高绿色供应链环境成本管理的透明度、实时性、效率性,引入具有数据集中、数据预处理、结果直观可视化功能的Power BI技术,结合高污染、高耗能的钢铁行业企业展开具体分析。研究发现,利用Power BI实现各供应链环节之中的环境成本情况明晰化,进而通过提升每个环节的绿色化能够有效降低企业环境成本,减少环境污染问题。 展开更多
关键词 绿色供应链 环境成本管理 power BI
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基于PowerBus总线的试飞测试数据采集技术研究
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作者 闫蓉 李卢丹 +1 位作者 尹川 吴金星 《电子测量技术》 北大核心 2025年第24期68-79,共12页
在机载测控领域,传感器的模拟量形式输出常受限于信号传输距离和电磁干扰的影响,导致信号失真和精度下降的问题,难以满足试飞测试对高精度数据采集的需求。此外,对于温度、压力等变化相对缓慢的信号,传统点对点多线制连接方式带来了布... 在机载测控领域,传感器的模拟量形式输出常受限于信号传输距离和电磁干扰的影响,导致信号失真和精度下降的问题,难以满足试飞测试对高精度数据采集的需求。此外,对于温度、压力等变化相对缓慢的信号,传统点对点多线制连接方式带来了布线复杂、安装成本高及系统灵活性受限等问题。为应对上述挑战,本文提出了一种基于PowerBus总线的传感器数字化采集技术方案。该方案利用PowerBus总线的能信一体低压载波技术和二线制连接特性,结合传感器数字化转换理念,构建了一个适用于缓变信号(如温度、压力)的高性能采集系统。采集系统由PowerBus主站(总线网络节点)和PowerBus从站(数字化传感器)组成。从站负责前端(包括铂电阻、热电偶、压力传感器)传感信号的采集、调理及高精度模数转换,并将数字化后的数据通过PowerBus总线传输;主站则负责管理PowerBus网络、接收来自各从站的数据,并进行数据封装与上传。实验结果表明:该系统能够实现1 ksps的内部采样频率和16 bit有效位数的采样精度,并在PowerBus总线9600 bps的速率限制下,实现了稳定可靠的多节点传感器数据传输,验证了该方案在机载测试等带宽受限环境下的可行性与高效性。 展开更多
关键词 数字化传感器 powerBus 能信一体 低压载波
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Performance analysis of scramjet including magnetohydrodynamic power generation after combustor
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作者 LIU Chenyuan WU Shaoxun MENG Hao 《推进技术》 北大核心 2025年第8期15-28,共14页
To investigate the overall performance of reverse energy bypass scramjet,firstly a variable spe⁃cific heat method combined with a chemical balance calculation module for combustion products were used to es⁃tablish a b... To investigate the overall performance of reverse energy bypass scramjet,firstly a variable spe⁃cific heat method combined with a chemical balance calculation module for combustion products were used to es⁃tablish a benchmark scramjet performance evaluation model.Based on the test data of typical flying point of Mach 7 with the altitude of 29 km,the reliability of the model was verified.The deviations of parameters such as the to⁃tal pressure loss of combustor between the model and the test data were analyzed.Furtherly,an analytical method for post-combustion magnetohydrodynamic power generation was established;by embedding the above method into the overall performance evaluation model,performance prediction considering the power generation effect was realized.Finally,based on the above model,variety regulations of the inlet and the outlet parameters of the power generation channel and performance parameters including the engine specific impulse and the unit thrust under different enthalpy extraction ratios and load factors were analyzed.It could be concluded that the model can reliably predict the variations of key parameters.As the value of the load factor increases,the value of the conduc⁃tivity required to reach the specified enthalpy extraction ratio first decreases and then increases,which is approxi⁃mately parabolic.In order to reduce the demand for the gas conductivity for MHD power generation,the load fac⁃tor should be around 0.5.When the load factor is 0.4 and the magnetic induction intensity is 2.5 T,if the enthalpy extraction ratio reaches 0.5%,the engine specific impulse performance reduces about 3.58%. 展开更多
关键词 SCRAMJET Energy bypass Magnetohydrodynamic power generation Chemical balance Performance evaluation
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W-band folded-waveguide traveling-wave tube with dual electron beams and H-plane power combining
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作者 Wang Huanyu Duan Jingrui +5 位作者 Wang Zhanliang Tang Haichen Lu Zhigang Wang Shaomeng Gong Huarong Gong Yubin 《强激光与粒子束》 北大核心 2025年第12期19-25,共7页
[Background]Traveling-wave tubes(TWTs)are widely applied in radar,imaging,and military systems owing to their excellent amplification characteristics.Miniaturization and integration are critical to the future of TWTs,... [Background]Traveling-wave tubes(TWTs)are widely applied in radar,imaging,and military systems owing to their excellent amplification characteristics.Miniaturization and integration are critical to the future of TWTs,with multi-channel slow-wave structures(SWSs)forming the foundation for their realization in high-power vacuum electronic devices.[Purpose]To provide design insights for multi-channel TWTs and simultaneously enhance their output power,a W-band folded-waveguide TWT with dual electron beams and H-plane power combining was proposed.[Methods]Three-dimensional electromagnetic simulations in CST were conducted to verify the highfrequency characteristics,electric field distribution,and amplification performance of the proposed SWS,thereby confirming the validity of the design.[Results]Results indicate that the designed TWT achieves a transmission bandwidth of 10 GHz.With an electron beam voltage of 17.9 kV and a current of 0.35 A,the output power reaches 450 W at 94 GHz,corresponding to an efficiency of 7.18%and a gain of 23.5 dB.Moreover,under fixed beam voltage and current,the TWT delivers over 200 W output power across 91–99 GHz,with a 3 dB bandwidth of 91–98.5 GHz.The particle voltage distribution after modulation further validates the mode analysis.[Conclusions]These results demonstrate the feasibility of compact dual-beam power-combining structures and provide useful guidance for the design of future multi-channel TWTs. 展开更多
关键词 double electron beam folded waveguide slow-wave structure power combining beam-wave interaction W-BAND
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An optimal design of the liquid-cooling plate channel in a power battery based on response surface methodology
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作者 Jinbo Zheng Jibin Jiang +2 位作者 Xiwei Yu Bingjun Yan Guofu Lian 《中国科学技术大学学报》 北大核心 2025年第2期52-65,51,I0002,共16页
The work takes a new liquid-cooling plate in a power battery with pin fins inside the channel as the object.A mathematical model is established via the central composite design of the response surface to study the rel... The work takes a new liquid-cooling plate in a power battery with pin fins inside the channel as the object.A mathematical model is established via the central composite design of the response surface to study the relationships among the length,width,height,and spacing of pin fins;the maximum temperature and temperature difference of the battery module;and the pressure drop of the liquid-cooling plate.Model accuracy is verified via variance analysis.The new liquid-cooling plate enables the power battery to work within an optimal temperature range.Appropriately increasing the length,width,and height and reducing the spacing of pin fins could reduce the temperature of the power battery module and improve the temperature uniformity.However,the pressure drop of the liquid-cooling plate increases.The structural parameters of the pin fins are optimized to minimize the maximum temperature and the temperature difference of the battery module as well as the pressure drop of the liquid-cooling plate.The errors between the values predicted and actual by the simulation test are 0.58%,4%,and 0.48%,respectively,which further verifies the model accuracy.The results reveal the influence of the structural parameters of the pin fins inside the liquid-cooling plate on its heat dissipation performance and pressure drop characteristics.A theoretical basis is provided for the design of liquid-cooling plates in power batteries and the optimization of structural parameters. 展开更多
关键词 response surface methodology power battery cooling channel optimal design
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Discussion on Methods and Influence Factors for Minimum Propulsion Power Assessment
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作者 ZHAN Xing−yu MAO Xiao−fei LI Ting−qiu 《船舶力学》 北大核心 2025年第6期888-900,共13页
Currently,the International Maritime Organization(IMO)has approved and implemented the assessment requirement for Minimum Propulsion Power(MPP)of ships in adverse sea conditions.The assessment method and relevant infl... Currently,the International Maritime Organization(IMO)has approved and implemented the assessment requirement for Minimum Propulsion Power(MPP)of ships in adverse sea conditions.The assessment method and relevant influence factors will have a vital impact on ship's design and operation.On the other hand,MPP is essentially a criterion for manoeuvring safety at actual seas.However,the practical assessment methods adopted in IMO guidelines do not directly and accurately account for ship's coursekeeping ability in severe seas.A time-domain comprehensive method with supplementary course-keeping ability criteria has been proposed in the authors'preliminary research.Based on an updated mathematical model and criteria,this paper presents more detailed elaborations,results and discussions on the time-domain method,including the comparative analyses with a power line method and two steady-state equilibrium methods based on IMO guidelines and draft.Discussions on the influences of key factors,involving criterion conditions and calculation parameters,are also presented.The results indicate that different methods exhibit varying advantages and complexity in MPP assessment,thus constituting a multi-level assessment framework for MPP.In particular,the time-domain comprehensive assessment has a higher accuracy with more realistic description of manoeuvre behaviors,capable of offering a solution for the ships that cannot meet other assessments,or for the assessment requiring additional course-keeping ability.Furthermore,an expanded range of wave direction sets a stricter but potentially necessary requirement,while using the self-propulsion factors at low speeds can eliminate the unnecessary conservation of assessment result caused by those at design speed. 展开更多
关键词 manoeuvrability in actual seas minimum propulsion power comprehensive assessment manoeuvrability criterion course keeping
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A class of quasilinear equations with-1 powers
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作者 ZHANG Heng SUN Yijing 《中国科学院大学学报(中英文)》 北大核心 2025年第1期13-19,共7页
This paper deals with quasilinear elliptic equations of singular growth like-Δu-uΔ(u^(2))=a(x)u^(-1).We establish the existence of positive solutions for general a(x)∈L^(p)(Ω),p>2,whereΩis a bounded domain inℝ... This paper deals with quasilinear elliptic equations of singular growth like-Δu-uΔ(u^(2))=a(x)u^(-1).We establish the existence of positive solutions for general a(x)∈L^(p)(Ω),p>2,whereΩis a bounded domain inℝ^(N)with N≥1. 展开更多
关键词 quasilinear singular equation -1 power elliptic equation
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Optimal Receiver Operating Characteristic Curve of Classical Conditional Power under Normal Models
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作者 ZHANG Ying-Ying 《应用概率统计》 北大核心 2025年第2期277-304,共28页
A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment ... A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment effect and interim result.For hypotheses and reversed hypotheses under normal models,we obtain analytical expressions of the ROC curves of the CCP,find optimal ROC curves of the CCP,investigate the superiority of the ROC curves of the CCP,calculate critical values of the False Positive Rate(FPR),True Positive Rate(TPR),and cutoff of the optimal CCP,and give go/no go decisions at the interim of the optimal CCP.In addition,extensive numerical experiments are carried out to exemplify our theoretical results.Finally,a real data example is performed to illustrate the go/no go decisions of the optimal CCP. 展开更多
关键词 area under the curve(AUC) classical conditional power(CCP) go/no go decisions historical and interim data receiver operating characteristic(ROC)curve
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容量限制Power图快速计算算法(英文) 被引量:1
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作者 郑利平 蔡瑞文 +3 位作者 郜文灿 江婷 曹力 张高峰 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2018年第5期791-800,共10页
与Voronoi图不同,Power图有着精确限容的特性,可应用于众多领域.在普通Power图上,通过给每个站点增加权重来添加容量限制约束,即得到容量限制Power图.现有容量限制Power图的生成算法时间复杂度高,速度较慢.本文首先对Power图权值对于容... 与Voronoi图不同,Power图有着精确限容的特性,可应用于众多领域.在普通Power图上,通过给每个站点增加权重来添加容量限制约束,即得到容量限制Power图.现有容量限制Power图的生成算法时间复杂度高,速度较慢.本文首先对Power图权值对于容量的单调性进行理论证明,然后提出了一种Power图权值的快速计算方法,相比于现有的试位法,能大幅提升容量限制Power图的生成性能.实验结果表明,文中算法具有速度快,精确度高,便于计算,密度适应性强等优点. 展开更多
关键词 power 容量限制剖分 质心power 解析法
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Improved power inversion algorithm based on derivative constraint
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作者 WANG Runnan LIU Hongchang +1 位作者 JIANG Siyuan LIU Shuai 《Journal of Systems Engineering and Electronics》 2025年第6期1398-1406,共9页
The power inversion(PI)algorithm lacks specific constraints on desired signals.Thus,the beampattern has fluctuation in all directions other than the jamming sources.This phenomenon will damage the reception of desired... The power inversion(PI)algorithm lacks specific constraints on desired signals.Thus,the beampattern has fluctuation in all directions other than the jamming sources.This phenomenon will damage the reception of desired signals.In high signal-to-noise ratio(SNR)application,the desired signal is inevitably suppressed by the PI algorithm,resulting in a deterioration to the out signal-to-interference-and-noise ratio(SINR).This paper proposes an improved PI algorithm based on derivative constraint.Firstly,the proposed method uses subspace projection to extract jamming-free data,the derivative constraint is imposed to the non-jamming data,and subsequently the Lagrange multiplier can be used to calculate the array weight vector.Simulation results demonstrate that,the proposed algorithm in this paper has a higher output SNR,flat gains in nonjamming directions,and applicability of high SINR than the PI algorithm,thus verifying the effectiveness of the algorithm. 展开更多
关键词 power inversion(PI) subspace projection derivative constraint flat gain
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Study, development and related application of a miniature compact pulsed power supply with high repetition frequency
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作者 Zhangfei Wang Jian Liu +1 位作者 Chunxia Yang Baoming Li 《Defence Technology(防务技术)》 2025年第5期304-318,共15页
Capacitor-based pulsed power supply(PPS)is widely used in fields related to electromagnetic launch,plasma,and materials'synthesis,modification and processing.As industrial applications place higher requirements on... Capacitor-based pulsed power supply(PPS)is widely used in fields related to electromagnetic launch,plasma,and materials'synthesis,modification and processing.As industrial applications place higher requirements on compact and portable pulsed power supplies,the National Key Laboratory of Transient Physics(NKLTP)recently developed a pulsed power supply consisting of a set of compact pulse-forming units(PFU),each with a capacitor energy storage of 220 kJ.This integrated PPS comes with a complete system configuration,a miniature compact structure,a high rate of repetition,and high power,with energy storage density exceeding 1.2 MJ/m^(3).This paper describes the device-level design of the unit,the system layout,the control system,the thermal management system,and the experimental results of the pulsed power supply.The experimental results verified the good reliability of the PPS at high repetition rates with each unit module delivering an output current of more than 100 kA.Additionally,flexible current pulse shapes can be formed by setting the charging voltage and the trigger sequence of the PFUs.The pulse forming network(PFN)developed from these PFUs was successfully applied to electromagnetic launch. 展开更多
关键词 Electromagnetic railgun Pulsed power supply Energy storage density Thermal management system Precision control system
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Power V和机械式随钻测斜仪在黑池1井的应用 被引量:20
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作者 刘以明 蔡文军 +2 位作者 王平 刘俊海 刘涛 《石油钻探技术》 CAS 北大核心 2006年第1期71-73,共3页
详细介绍了Power V垂直钻井系统和机械式无线随钻测斜仪的组成、工作原理及其在黑池1井的应用情况。现场应用表明,Power V系统可以解决高陡地层和自然造斜率大地层的垂直钻井问题,改善井身质量,提高钻井速度;机械式无线随钻测斜仪具有... 详细介绍了Power V垂直钻井系统和机械式无线随钻测斜仪的组成、工作原理及其在黑池1井的应用情况。现场应用表明,Power V系统可以解决高陡地层和自然造斜率大地层的垂直钻井问题,改善井身质量,提高钻井速度;机械式无线随钻测斜仪具有操作使用方便、抗高温高压、测量结果稳定等优点,既能满足应用Power V系统垂直钻井过程中随钻监测井斜的需要,又可降低钻井成本。 展开更多
关键词 垂直钻井 power V 随钻测斜仪 井斜控制 机械钻速 黑池1井
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GT-Power软件的微型车消声器设计与优化 被引量:17
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作者 颜伏伍 杨伦 +1 位作者 刘志恩 黄恒 《内燃机工程》 EI CAS CSCD 北大核心 2010年第2期64-67,共4页
采用GT-Power软件实现了对微型车CN100消声器的设计和优化。通过建立消声器消声性能与发动机工作过程的耦合仿真模型,完成了消声器声学性能和空气动力性的仿真分析。在耦合模型中,插入损失与压力损失可在一次计算过程中同时获得,减少了... 采用GT-Power软件实现了对微型车CN100消声器的设计和优化。通过建立消声器消声性能与发动机工作过程的耦合仿真模型,完成了消声器声学性能和空气动力性的仿真分析。在耦合模型中,插入损失与压力损失可在一次计算过程中同时获得,减少了计算时间。采用仿真和试验验证相结合的方法,针对尾管总体噪声值和四阶噪声值高于设计要求,对消声器进行了改进,改进后尾管的总体噪声值下降了6.4 dB(A),基本达到了设计要求。 展开更多
关键词 内燃机 消声器 性能仿真 GT—power
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Power图的性质及构造算法研究 被引量:15
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作者 吴壮志 杨钦 怀进鹏 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2001年第12期1057-1062,共6页
点集的 Power图是点集 Voronoi图的推广 ,特别适合用来解决涉及球 (圆 )的几何问题 .文中首先对 Power图的基本性质进行了几何化的证明 ;之后 ,研究了权为负数时对 Power图的影响 ,指出在 Power图的理论中允许权为负数 ,从而 Power图可... 点集的 Power图是点集 Voronoi图的推广 ,特别适合用来解决涉及球 (圆 )的几何问题 .文中首先对 Power图的基本性质进行了几何化的证明 ;之后 ,研究了权为负数时对 Power图的影响 ,指出在 Power图的理论中允许权为负数 ,从而 Power图可以应用到具有负权性质的领域 ;最后 ,给出了平面点集的 Power图的构造算法 ,该算法利用 Power图与正则三角化互为对偶的原理 ,在点集的正则三角化的基础上构造 Power图 ,同时给出了实例以说明算法的有效性 . 展开更多
关键词 带权Voronoi图 power Laguerre图 正则三角化 构造算法 计算机图形学
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运用品管圈降低Power PICC堵管率的实践 被引量:11
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作者 王莉莉 王蓓 +1 位作者 韩玲 吴蒙 《中国护理管理》 CSCD 2015年第11期1390-1394,共5页
目的 :探讨开展品管圈活动对降低Power PICC(耐高压注射型经外周置入的中心静脉导管)带管患者堵管率的有效性。方法:在实施品管圈前的2014年5-6月随机选取278例Power PICC带管患者及在实施品管圈后的2014年11-12月随机选取251例Power P... 目的 :探讨开展品管圈活动对降低Power PICC(耐高压注射型经外周置入的中心静脉导管)带管患者堵管率的有效性。方法:在实施品管圈前的2014年5-6月随机选取278例Power PICC带管患者及在实施品管圈后的2014年11-12月随机选取251例Power PICC带管患者,其中5-6月的278例患者采取常规导管护理模式,11-12月的251例患者运用品管圈管理Power PICC带管患者,包括分析患者堵管的原因,设定目标,制定相应的对策及实施,观察分析品管圈活动前后堵管率情况。结果:对Power PICC带管患者进行品管圈干预后,患者的堵管率由28.4%降低至12.0%,差异有统计学意义(P<0.05)。结论 :开展品管圈活动可以降低Power PICC带管患者的堵管率,保护了患者血管通路。 展开更多
关键词 品管圈 power PICC 堵管率
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基于GT-Power的DPF喷油催化燃烧再生仿真技术 被引量:4
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作者 侯献军 马义 +2 位作者 彭辅明 颜伏伍 张献安 《北京理工大学学报》 EI CAS CSCD 北大核心 2011年第1期19-23,共5页
利用GT-Power软件建立DPF喷油催化燃烧再生系统仿真模型,从喷油率和补气策略两方面对DPF提温过程进行优化,优化后的DPF提温时间缩短了37.9%,DPF出口最高温度增加了3.4%.通过建立DPF微粒燃烧模型,分析了再生微粒燃烧过程中载体壁面温度... 利用GT-Power软件建立DPF喷油催化燃烧再生系统仿真模型,从喷油率和补气策略两方面对DPF提温过程进行优化,优化后的DPF提温时间缩短了37.9%,DPF出口最高温度增加了3.4%.通过建立DPF微粒燃烧模型,分析了再生微粒燃烧过程中载体壁面温度及微粒(PM)层厚度分布情况.计算结果表明,载体温度由前端向后依次升高,最高温度出现在载体后端中心;微粒由载体前端向后逐渐燃烧,后端微粒燃烧速度快于前端. 展开更多
关键词 GT—power 微粒捕集器 再生 仿真
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