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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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Minimum safe thickness of rock plug in karst tunnel according to upper bound theorem 被引量:13
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作者 YANG Zi-han ZHANG Jia-hua 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第9期2346-2353,共8页
High pressure and water-bearing caverns ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technic... High pressure and water-bearing caverns ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technical problem to be solved for karst tunnel construction. Based on the Hoek-Brown nonlinear failure criterion, the minimum safe thickness of rock plug was investigated in the light of the limit analysis theory. On the basis of the proposed failure mode, the expression of the minimum thickness for rock plug was obtained by means of upper bound theorem in combination with variational principle. The calculation results show the influence of each parameter on safe thickness and reveal the damage range of rock plug. The proposed method is verified by comparing the results with those of the drain cavern of Maluqing Tunnel. The research shows that with the increase of compressive strength and tensile strength as well as constant A of Hoek-Brown criterion, the safe thickness decreases, whereas with the increase of cavern pressure, tunnel diameter, and constant B from Hoek-Brown criterion, the safe thickness increases. Besides, the tensile strength, or constants A and B affect the shear failure angle of rock plug structure, but other parameters do not. In conclusion, the proposed method can predict the minimum safe thickness of rock plug, and is useful for water burst study and prevention measures of tunnels constructed in high-risk karst regions. 展开更多
关键词 karst tunnels rock plug minimum safe thickness upper limit theorem failure mode
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Finding the Minimum Ratio Traveling Salesman Tour by Artificial Ants 被引量:4
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作者 马良 崔雪丽 姚俭 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2003年第3期24-27,共4页
Ants of artificial colony are able to generate good solutions to the famous traveling salesman problem (TSP). We propose an artificial ants algorithm for solving the minimum ratio TSP, which is more general than the s... Ants of artificial colony are able to generate good solutions to the famous traveling salesman problem (TSP). We propose an artificial ants algorithm for solving the minimum ratio TSP, which is more general than the standard TSP in combinatorial optimization area. In the minimum ratio TSP, another criterion concerning each edge is added, that is, the traveling salesman can have a benefit if he travels from one city to another. The objective is to minimize the ratio between total costs or distances and total benefits. The idea of this type of optimization is in some sense quite similar to that of traditional cost-benefit analysis in management science. Computational results substantiate the solution quality and efficiency of the algorithm. 展开更多
关键词 minimum ratio TraveLing salesman problem Ant algorithm.
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Adaptive diagonal loaded minimum variance beamforming applied to medical ultrasound imaging 被引量:2
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作者 刘昊霖 张志宏 刘东权 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期1826-1832,共7页
In order to enhance the robustness and contrast in the minimum variance(MV) beamformer, adaptive diagonal loading method was proposed. The conventional diagonal loading technique has already been used in the MV beamfo... In order to enhance the robustness and contrast in the minimum variance(MV) beamformer, adaptive diagonal loading method was proposed. The conventional diagonal loading technique has already been used in the MV beamformer, but has the drawback that its level is specified by predefined parameter and without consideration of input-data. To alleviate this problem, the level of diagonal loading was computed appropriately and automatically from the given data by shrinkage method in the proposed adaptive diagonal loaded beamformer. The performance of the proposed beamformer was tested on the simulated point target and cyst phantom was obtained using Field II. In the point target simulation, it is shown that the proposed method has higher lateral resolution than the conventional delay-and-sum beamformer and could be more robust in estimating the amplitude peak than the MV beamformer when acoustic velocity error exists. In the cyst phantom simulation, the proposed beamformer has shown that it achieves an improvement in contrast ratio and without distorting the edges of cyst. 展开更多
关键词 medical ultrasound imaging minimum variance BEAMFORMING DIAGONAL loading delay-and-sum BEAMFORMING CONTRAST ROBUSTNESS
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Relationship between diameter of split Hopkinson pressure bar and minimum loading rate under rock failure 被引量:6
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作者 李夕兵 洪亮 +2 位作者 尹土兵 周子龙 叶洲元 《Journal of Central South University of Technology》 EI 2008年第2期218-223,共6页
In order to investigate the relationship between bar diameter and loading rate of the split Hopkinson pressure bar(SHPB) setup under the failure of rock specimen and realize the medium strain rate loading of specimen,... In order to investigate the relationship between bar diameter and loading rate of the split Hopkinson pressure bar(SHPB) setup under the failure of rock specimen and realize the medium strain rate loading of specimen,new SHPB setups with different elastic bar's diameters of 22,36,50 and 75 mm were constructed.The tests were carried out on these setups at different loading rates,and the specimens had the same diameter of elastic bars and same ratio of length to diameter.The test results show that the larger the elastic bar's diameter is,the less the loading rate is needed to cause specimen failure,they show good power relationship,and that under the same strain rate loading,specimens are broken more seriously with larger diameter SHPB setup than with smaller one. 展开更多
关键词 rock failure Hopkinson pressure bar DIAMETER minimum loading rate medium strain rate
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Enhanced minimum attribute reduction based on quantum-inspired shuffled frog leaping algorithm 被引量:3
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作者 Weiping Ding Jiandong Wang +1 位作者 Zhijin Guan Quan Shi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2013年第3期426-434,共9页
Attribute reduction in the rough set theory is an important feature selection method, but finding a minimum attribute reduction has been proven to be a non-deterministic polynomial (NP)-hard problem. Therefore, it i... Attribute reduction in the rough set theory is an important feature selection method, but finding a minimum attribute reduction has been proven to be a non-deterministic polynomial (NP)-hard problem. Therefore, it is necessary to investigate some fast and effective approximate algorithms. A novel and enhanced quantum-inspired shuffled frog leaping based minimum attribute reduction algorithm (QSFLAR) is proposed. Evolutionary frogs are represented by multi-state quantum bits, and both quantum rotation gate and quantum mutation operators are used to exploit the mechanisms of frog population diversity and convergence to the global optimum. The decomposed attribute subsets are co-evolved by the elitist frogs with a quantum-inspired shuffled frog leaping algorithm. The experimental results validate the better feasibility and effectiveness of QSFLAR, comparing with some representa- tive algorithms. Therefore, QSFLAR can be considered as a more competitive algorithm on the efficiency and accuracy for minimum attribute reduction. 展开更多
关键词 minimum attribute reduction quantum-inspired shuf- fled frog leaping algorithm multi-state quantum bit quantum rotation gate and quantum mutation elitist frog.
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A novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise,minimum mean square variance criterion and least mean square adaptive filter 被引量:9
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作者 Yu-xing Li Long Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第3期543-554,共12页
Underwater acoustic signal processing is one of the research hotspots in underwater acoustics.Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing.Owing to the complexity ... Underwater acoustic signal processing is one of the research hotspots in underwater acoustics.Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing.Owing to the complexity of marine environment and the particularity of underwater acoustic channel,noise reduction of underwater acoustic signals has always been a difficult challenge in the field of underwater acoustic signal processing.In order to solve the dilemma,we proposed a novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN),minimum mean square variance criterion(MMSVC) and least mean square adaptive filter(LMSAF).This noise reduction technique,named CEEMDAN-MMSVC-LMSAF,has three main advantages:(i) as an improved algorithm of empirical mode decomposition(EMD) and ensemble EMD(EEMD),CEEMDAN can better suppress mode mixing,and can avoid selecting the number of decomposition in variational mode decomposition(VMD);(ii) MMSVC can identify noisy intrinsic mode function(IMF),and can avoid selecting thresholds of different permutation entropies;(iii) for noise reduction of noisy IMFs,LMSAF overcomes the selection of deco mposition number and basis function for wavelet noise reduction.Firstly,CEEMDAN decomposes the original signal into IMFs,which can be divided into noisy IMFs and real IMFs.Then,MMSVC and LMSAF are used to detect identify noisy IMFs and remove noise components from noisy IMFs.Finally,both denoised noisy IMFs and real IMFs are reconstructed and the final denoised signal is obtained.Compared with other noise reduction techniques,the validity of CEEMDAN-MMSVC-LMSAF can be proved by the analysis of simulation signals and real underwater acoustic signals,which has the better noise reduction effect and has practical application value.CEEMDAN-MMSVC-LMSAF also provides a reliable basis for the detection,feature extraction,classification and recognition of underwater acoustic signals. 展开更多
关键词 Underwater acoustic signal Noise reduction Empirical mode decomposition(EMD) Ensemble EMD(EEMD) Complete EEMD with adaptive noise(CEEMDAN) minimum mean square variance criterion(MMSVC) Least mean square adaptive filter(LMSAF) Ship-radiated noise
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Recursive weighted least squares estimation algorithm based on minimum model error principle 被引量:2
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作者 雷晓云 张志安 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第2期545-558,共14页
Kalman filter is commonly used in data filtering and parameters estimation of nonlinear system,such as projectile's trajectory estimation and control.While there is a drawback that the prior error covariance matri... Kalman filter is commonly used in data filtering and parameters estimation of nonlinear system,such as projectile's trajectory estimation and control.While there is a drawback that the prior error covariance matrix and filter parameters are difficult to be determined,which may result in filtering divergence.As to the problem that the accuracy of state estimation for nonlinear ballistic model strongly depends on its mathematical model,we improve the weighted least squares method(WLSM)with minimum model error principle.Invariant embedding method is adopted to solve the cost function including the model error.With the knowledge of measurement data and measurement error covariance matrix,we use gradient descent algorithm to determine the weighting matrix of model error.The uncertainty and linearization error of model are recursively estimated by the proposed method,thus achieving an online filtering estimation of the observations.Simulation results indicate that the proposed recursive estimation algorithm is insensitive to initial conditions and of good robustness. 展开更多
关键词 minimum model error Weighted least squares method State estimation Invariant embedding method Nonlinear recursive estimate
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Minimum eigenvalue based adaptive fault compensation for hypersonic vehicles 被引量:1
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作者 MA Yajie JIANG Bin REN Hao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第2期492-500,共9页
The attitude tracking control problem is addressed for hypersonic vehicles under actuator faults that may cause an uncertain time-varying control gain matrix.An adaptive compensation scheme is developed to ensure syst... The attitude tracking control problem is addressed for hypersonic vehicles under actuator faults that may cause an uncertain time-varying control gain matrix.An adaptive compensation scheme is developed to ensure system stability and asymptotic tracking properties,including a kinematic control signal and a dynamic control signal.To deal with the uncertainties of the control gain matrix,a new positive definite one is constructed.The minimum eigenvalue of such a new control gain matrix is estimated.Simulation results of application to an X-33 vehicle model verify the effectiveness of the proposed minimum eigenvalue based adaptive fault compensation scheme. 展开更多
关键词 actuator fault adaptive compensation hypersonic vehicle minimum eigenvalue
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Analyzing the Completeness(Relative Minimum Magnitude) of History Seismic Catalogue in Sichuan Province
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作者 Li Sun,Mingzhong Tian School of the Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China. 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期51-51,共1页
Sichuan Province,East Western of China,within the area of east longitude 97°21′-108°31′,north latitude 26°03′-34°19′,which is on the Mediterranean seismic zone;with its complicated geological b... Sichuan Province,East Western of China,within the area of east longitude 97°21′-108°31′,north latitude 26°03′-34°19′,which is on the Mediterranean seismic zone;with its complicated geological background,several strong shocks occurred in this district since ancient times.Earthquake catalogue of this area could date back to B.C.26,however,limited by the conditions—technology or funds,lots of minor earthquake have been lost,which could be 展开更多
关键词 HISTORY SEISMIC CATALOGUE Sichuan Province RELATIVE minimum MAGNITUDE SURFACE-WAVE MAGNITUDE local-wave MAGNITUDE Gutenberg-Richter relation
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Minimum Distortion Direction Prediction-based Fast Half-pixel Motion Vector Search Algorithm
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作者 董海燕 张其善 《Defence Technology(防务技术)》 SCIE EI CAS 2005年第2期182-186,共5页
A minimum distortion direction prediction-based novel fast half-pixel motion vector search algorithm is proposed, which can reduce considerably the computation load of half-pixel search. Based on the single valley cha... A minimum distortion direction prediction-based novel fast half-pixel motion vector search algorithm is proposed, which can reduce considerably the computation load of half-pixel search. Based on the single valley characteristic of half-pixel error matching function inside search grid, the minimum distortion direction is predicted with the help of comparative results of sum of absolute difference(SAD) values of four integer-pixel points around integer-pixel motion vector. The experimental results reveal that, to all kinds of video sequences, the proposed algorithm can obtain almost the same video quality as that of the half-pixel full search algorithm with a decrease of computation cost by more than 66%. 展开更多
关键词 VIDEO compression motion estimation COMPUTATIONAL COMPLEXITY half-pixel SEARCH minimum DISTORTION direction PREDICTION
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Single-channel speech enhancement method based on masking properties and minimum statistics
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作者 JiangXiaoping YaoTianren FuHua 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2004年第2期217-224,共8页
A single-channel speech enhancement method of noisy speech signals at very low signal-to-noise ratios is presented, which is based on masking properties of the human auditory system and power spectral density estimati... A single-channel speech enhancement method of noisy speech signals at very low signal-to-noise ratios is presented, which is based on masking properties of the human auditory system and power spectral density estimation of non stationary noise. It allows for an automatic adaptation in time and frequency of the parametric enhancement system, and finds the best tradeoff among the amount of noise reduction, the speech distortion, and the level of musical residual noise based on a criterion correlated with perception and SNR. This leads to a significant reduction of the unnatural structure of the residual noise. The results with several noise types show that the enhanced speech is more pleasant to a human listener. 展开更多
关键词 auditory property masking varying SNR estimation speech enhancement minimum statistics.
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Minimum-energy leader-following formation of distributed multiagent systems with communication constraints
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作者 QIN Donghao WANG Le +1 位作者 GAO Jiuan XI Jianxiang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第6期1419-1431,共13页
This paper concerns minimum-energy leader-following formation design and analysis problems of distributed multiagent systems(DMASs)subjected to randomly switching topologies and aperiodic communication pauses.The crit... This paper concerns minimum-energy leader-following formation design and analysis problems of distributed multiagent systems(DMASs)subjected to randomly switching topologies and aperiodic communication pauses.The critical feature of this paper is that the energy consumption during the formation control process is restricted by the minimum-energy constraint in the sense of the linear matrix inequality.Firstly,the leader-following formation control protocol is proposed based on the relative state information of neighboring agents,where the total energy consumption is considered.Then,minimum-energy leader-following formation design and analysis criteria are presented in the form of the linear matrix inequality,which can be checked by the generalized eigenvalue method.Especially,the value of the minimum-energy constraint is determined.An illustrative simulation is provided to show the effectiveness of the main results. 展开更多
关键词 multi-agent system leader-following formation communication pause minimum energy.
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Novel Minimum Passive Element Realization of All-Pass Network Using A Modified Current Conveyor
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作者 Wu JieDepartment of Electrical Engineering, Hunan University, Changsha, Hunan, China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1992年第2期78-80,共3页
1. IntroductionA large number of networks for realizing first and second order transfer functions using a currentconveyor have been reported in the literature. Especially, the networks that can offer highinput impedan... 1. IntroductionA large number of networks for realizing first and second order transfer functions using a currentconveyor have been reported in the literature. Especially, the networks that can offer highinput impedance attract attention, for high input impedance has the advantage that the networksmay be used in cascade without requiring impedance matching device. In the Higashimura and 展开更多
关键词 In Novel minimum Passive Element Realization of All-Pass Network Using A Modified Current Conveyor
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Online Minimum-acceleration Trajectory Planning with the Kinematic Constraints 被引量:2
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作者 WANG Ying-Shi 《自动化学报》 EI CSCD 北大核心 2014年第7期1328-1338,共11页
关键词 运动规划 约束规划 机器人系统 充分必要条件 加加速度 自由度 轨迹规划 运动约束
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基于线性化的单级式双有源桥AC-DC变换器最小电流应力控制策略 被引量:1
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作者 王要强 钟正阳 +2 位作者 李想 聂福全 梁军 《电工技术学报》 北大核心 2025年第10期3224-3235,共12页
针对单级式双有源桥AC-DC变换器调制非线性和电流应力较大的问题,该文提出一种基于线性化的变换器最小电流应力控制策略。首先,分析扩展移相(EPS)调制策略的开关特性,对于输入电流与移相比呈非线性的特点,提出一种线性化变频移相控制策... 针对单级式双有源桥AC-DC变换器调制非线性和电流应力较大的问题,该文提出一种基于线性化的变换器最小电流应力控制策略。首先,分析扩展移相(EPS)调制策略的开关特性,对于输入电流与移相比呈非线性的特点,提出一种线性化变频移相控制策略。其次,通过微分极值法实现变换器电流应力的最小化,该控制策略不仅可以降低变换器的控制复杂度,还可以在有效降低变换器电流应力的同时保证开关管具有较宽零电压开通(ZVS)范围,并且移相比和开关频率以解析形式获得,计算简单、易于实现。最后,通过仿真和实验对该文所提控制策略进行验证,证明了该控制策略的可行性。 展开更多
关键词 AC-DC变换器 扩展移相 线性化 最小电流应力 零电压软开关
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狭窄环境下基于风险概率量化的车辆轨迹规划方法 被引量:1
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作者 徐晓苏 迟骋 周帅 《中国惯性技术学报》 北大核心 2025年第4期383-393,共11页
为解决自主移动车辆在狭窄环境中路径规划困难以及在动态环境下安全性难以保障的问题,提出了一种适用于狭窄环境的基于风险概率量化的轨迹规划方法。引入风险意识,通过高斯概率模型对动态障碍物的风险区域进行建模,从而评估不同碰撞概... 为解决自主移动车辆在狭窄环境中路径规划困难以及在动态环境下安全性难以保障的问题,提出了一种适用于狭窄环境的基于风险概率量化的轨迹规划方法。引入风险意识,通过高斯概率模型对动态障碍物的风险区域进行建模,从而评估不同碰撞概率风险区域,将是否能通行问题转化成为可接受风险概率下的轨迹规划问题。不同于传统的质点模型,所提方法支持更精细的自身车辆区域建模,采用基于超平面的描述,结合风险区域与轨迹规划问题,提出新的自车区域与障碍物风险区域之间的最小距离约束条件。通过在多个挑战性场景中的仿真和实机测试,实验结果表明,所提方法在狭窄环境中表现优异,且在动态环境具备风险意识,在静态障碍物仿真实验中路径平滑度提高至少26.89%,在动态环境中安全距离增大至少16.75%。 展开更多
关键词 狭窄环境 风险意识 最小距离约束 轨迹规划
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三元活性金属燃料Al/B/Mg和Al/B/MgH2的燃烧特性 被引量:1
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作者 程志鹏 夏语 +5 位作者 罗一民 马腾 徐飞扬 张宇 吴星亮 徐森 《含能材料》 北大核心 2025年第3期246-255,共10页
为探究三元活性金属燃料Al/B/Mg(ABM)和Al/B/MgH2(ABM-H)的燃烧特性,分别利用氧弹量热仪和哈特曼管研究样品的燃烧热与最小点火能,借助高速摄像系统与高速红外摄像系统研究火焰传播亚瞬态过程和温度场域时空分布特性。研究结果表明:ABM... 为探究三元活性金属燃料Al/B/Mg(ABM)和Al/B/MgH2(ABM-H)的燃烧特性,分别利用氧弹量热仪和哈特曼管研究样品的燃烧热与最小点火能,借助高速摄像系统与高速红外摄像系统研究火焰传播亚瞬态过程和温度场域时空分布特性。研究结果表明:ABM、ABM-H的燃烧热值分别为34.1 MJ·kg^(-1)和32.2 MJ·kg^(-1),较纯Al的燃烧热值(29.8 MJ·kg^(-1))分别提高了14.4%和8.1%;ABM、ABM-H和Al的最小点火能量分别在160~170,100~110,20~30 mJ之间;质量浓度为625 g·m^(-3)时,ABM和ABM-H较纯Al燃烧持续时间分别增加了65.5%和34.5%,火焰传播速度峰值分别提升了12.6%和23.0%。质量浓度在500 g·m^(-3)条件下,ABM-H和ABM的火焰传播速度峰值均最大,分别为45.05 m·s^(-1)和38.7 m·s^(-1),火焰表面最高温度峰值分别为1856℃和1717℃,ABM-H较ABM提高了7.6%,同时升温速率更快。可见,ABM和ABM-H配方在显著降低粉尘/空气混合物爆炸危险性的同时,燃烧性能明显提高,且ABM在燃烧热值和燃烧持续时间上表现出更好的热效应,ABM-H在最小点火能量、火焰传播速度和温度上升速率方面表现出更高的反应活性。 展开更多
关键词 三元活性金属燃料 最小点火能 火焰传播特性 温度场分布
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吉木萨尔凹陷芦草沟组页岩油有效储层物性下限研究 被引量:1
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作者 李映艳 邓远 +5 位作者 何吉祥 彭寿昌 宋斯宇 李一鸣 范青青 刘达东 《断块油气田》 北大核心 2025年第1期20-26,共7页
吉木萨尔凹陷芦草沟组页岩油储层为陆源碎屑-碳酸盐-火山碎屑多元混积层系。文中基于高压压汞、核磁共振和N2吸附实验,综合利用经验统计法、孔渗关系法、核磁共振法、水膜厚度法、含油产状法和J函数法对芦草沟组页岩油储层的孔隙度与渗... 吉木萨尔凹陷芦草沟组页岩油储层为陆源碎屑-碳酸盐-火山碎屑多元混积层系。文中基于高压压汞、核磁共振和N2吸附实验,综合利用经验统计法、孔渗关系法、核磁共振法、水膜厚度法、含油产状法和J函数法对芦草沟组页岩油储层的孔隙度与渗透率下限开展研究。结果表明,通过各类方法计算得到的芦草沟组有效储层孔隙度下限分布范围在3.88%~6.57%,渗透率下限分布范围在0.0059×10^(-3)~0.0120×10^(-3)μm^(2)。综合分析各方法优缺点及适用性,最终优选出核磁共振法与水膜厚度法2种方法来明确芦草沟组有效储层物性下限,得到芦草沟组页岩油有效储层孔隙度下限为5.92%、渗透率下限为0.01×10^(-3)μm^(2)。研究成果可为该地区页岩油藏开发和储量计算提供可靠支撑。 展开更多
关键词 页岩油 有效储层 物性下限 最小流动孔喉半径 芦草沟组
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共同富裕进程中低保标准的区域差异、空间格局及区域均衡化评估 被引量:3
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作者 王强 《华中科技大学学报(社会科学版)》 北大核心 2025年第2期19-27,共9页
共同富裕进程中,低保制度作为实现共同富裕目标的重要政策工具,扮演着保障民生、促进社会公平、缩小贫富差距的重要角色。本研究以2020—2023年地级市低保标准数据为基础,采用基尼系数、变异系数、极差值和空间自相关等方法,系统评估了... 共同富裕进程中,低保制度作为实现共同富裕目标的重要政策工具,扮演着保障民生、促进社会公平、缩小贫富差距的重要角色。本研究以2020—2023年地级市低保标准数据为基础,采用基尼系数、变异系数、极差值和空间自相关等方法,系统评估了低保标准在省际及省内各地级市间的差异特征及其动态变化。同时,通过对收入替代率和消费替代率的分析,评估了低保标准的区域均衡化水平。研究发现,共同富裕加速推进背景下,低保标准的区域差异和地区不平等程度不仅未缩小,反而进一步扩大。空间自相关分析揭示了低保标准的空间聚集效应,表明区域经济和社会发展的不均衡性是导致低保标准区域差异的重要原因。通过对低保标准区域均衡化的分析发现,城市低保标准区域均衡化水平相对较高,农村低保标准区域均衡化水平却较低。基于上述分析,提出在共同富裕进程中,低保标准改革优化应遵循“地方适配-区域均衡”的双重导向,并提出“省级指导线+市级调整区间+区域协同优化”的政策优化路径,旨在通过央地协同机制,推动低保标准的区域均衡化,确保低保标准既能满足地方贫困需求,又能促进区域间的公平发展,助力共同富裕目标的实现。 展开更多
关键词 共同富裕 最低生活保障标准 区域差异 空间聚集特征 区域均衡
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