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Efficient fastest-path computations for road maps

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Computational Visual Media 2021年第2期7卷 267-281页

作者： renjie Chen Craig Gotsman University of Science and Technology of China HefeiChina New Jersey Institute of Technology NewarkNJUSA

In the age of real-time online traffic information and GPS-enabled devices,fastest-path computations between two points in a road network modeled as a directed graph,where each directed edge is weighted by a“travel time”value,are becoming a standard feature of many navigation-related *** support this,very efficient computation of these paths in very large road networks is *** paths may be computed as minimal-cost paths in a weighted directed graph,but traditional minimal-cost path algorithms based on variants of the classical Dijkstra algorithm do not scale well,as in the worst case they may traverse the entire graph.A common improvement,which can dramatically reduce the number of graph vertices traversed,is the A*algorithm,which requires a good heuristic lower bound on the minimal *** introduce a simple,but very effective,heuristic function based on a small number of values assigned to each graph *** values are based on graph separators and are computed efficiently in a preprocessing *** present experimental results demonstrating that our heuristic provides estimates of the minimal cost superior to those of other *** experiments show that when used in the A*algorithm,this heuristic can reduce the number of vertices traversed by an order of magnitude compared to other heuristics.

关键词： shortest-path road map heuristic GPS navigation A^(*)search

Resonance in flow past oscillating cylinder under subcritical conditions

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Applied Mathematics and Mechanics(English Edition) 2017年第3期38卷 363-378页

作者： renjie JIANG Pengjun ZHENG Faculty of Maritime and Transportation Ningbo University Ningbo 315211 Zhejiang Province China National Traffic Management Engineering and Technology Research Centre Ningbo University Sub-centre Ningbo 315211 Zhejiang Province China Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies Nanjing 210096 China

Flow around an oscillating cylinder in a subcritical region are numerically studied with a lattice Boltzmann method(LBM). The effects of the Reynolds number,oscillation amplitude and frequency on the vortex wake modes and hydrodynamics forces on the cylinder surface are systematically investigated. Special attention is paid to the phenomenon of resonance induced by the cylinder oscillation. The results demonstrate that vortex shedding can be excited extensively under subcritical conditions, and the response region of vibration frequency broadens with increasing Reynolds number and oscillation amplitude. Two distinct types of vortex shedding regimes are observed. The first type of vortex shedding regime(VSR I) is excited at low frequencies close to the intrinsic frequency of flow, and the second type of vortex shedding regime(VSR II)occurs at high frequencies with the Reynolds number close to the critical value. In the VSR I, a pair of alternately rotating vortices are shed in the wake per oscillation cycle,and lock-in/synchronization occurs, while in the VSR II, two alternately rotating vortices are shed for several oscillation cycles, and the vortex shedding frequency is close to that of a stationary cylinder under the critical condition. The excitation mechanisms of the two types of vortex shedding modes are analyzed separately.

关键词： oscillating cylinder subcritical region resonance phenomenon lattice Boltzmann method(LBM)

LitePIG: a lite parameter inference system for the gravitational wave in the millihertz band

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Communications in Theoretical Physics 2023年第7期75卷 113-122页

作者： renjie Wang Bin Hu Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing102206China Department of Astronomy Beijing Normal UniversityBeijing100875China

We present a Python based parameter inference system for the gravitational wave(GW)measured in the millihertz *** system includes the following features:the GW waveform originated from the massive black hole binaries(MBHB),the stationary instrumental Gaussian noise,the higher-order harmonic modes,the full response function from the time delay interferometry and the Gaussian likelihood function with the dynamic nested parameter *** particular,we highlight the role of higher-order *** including these modes,the luminosity distance estimation precision can be improved roughly by a factor of 50,compared with the case with only the leading order(l=2,|m|=2)*** is due to the response functions of different harmonic modes on the inclination angle are ***,it can help to break the distance-inclination ***,we show the robustness of testing general relativity(GR)by using higher-order *** results show that the GW from MBHB can simultaneously constrain four of the higher harmonic amplitudes(deviation from GR)with 95%confidence level of c21=0.54-1.05+0.82,c32=-0.65-1.42+3.02,c33=0.56-0.96^(+0.79) and c44=1.57-2.19^(+3.22),respectively.

关键词： gravitational wave astronomy data analysis parameter estimation

RELATIONS BETWEEN INTERFACE OF CF/Al-4.5 Cu COMPOSITE AND SOLIDIFICATION PROCESSING

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中国有色金属学会会刊：英文版 1997年第2期7卷 133-137页

作者： Chu, Shuangjie Wu, renjie Shanghai Jiao Tong Univ Shanghai China

ＲＥＬＡＴＩＯＮＳＢＥＴＷＥＥＮＩＮＴＥＲＦＡＣＥＯＦＣＦ／Ａｌ４．５ＣｕＣＯＭＰＯＳＩＴＥＡＮＤＳＯＬＩＤＩＦＩＣＡＴＩＯＮＰＲＯＣＥＳＳＩＮＧ①ＣｈｕＳｈｕａｎｇｊｉｅ，ＷｕＲｅｎｊｉｅＲｅｓｅａｒｃｈＩｎｓｔ... 详细信息

ＲＥＬＡＴＩＯＮＳＢＥＴＷＥＥＮＩＮＴＥＲＦＡＣＥＯＦＣＦ／Ａｌ４．５ＣｕＣＯＭＰＯＳＩＴＥＡＮＤＳＯＬＩＤＩＦＩＣＡＴＩＯＮＰＲＯＣＥＳＳＩＮＧ①ＣｈｕＳｈｕａｎｇｊｉｅ，ＷｕＲｅｎｊｉｅＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＣｏｍｐｏｓｉｔｅＭ...

关键词： CF/Al 4.5Cu composite interface solidification cooling rate

Recent Advances in Oxidative ipso-Annulation of N-Arylpropiolamides

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Chinese Journal of Chemistry 2017年第3期35卷 280-288页

作者： renjie Song Yexiang Xie Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle Nanchang Hangkong University Nanchang Jiangxi 330063 China

Oxidative radical reactions have attracted much attention due to their extensive applications in organic synthesis. We herein summarize recent progress in the oxidative ipso-annulation of N-arylpropiolamides with various functional reagents, including ethers, alkanes, aldehydes, NaSO2CF3, tert-butyl nitrite, disulfides, thiophenols, sulfonylhydrazides, AgSCF3, tetra-n-butyl ammonium bromide (TBAB), phosphorus and silanes, for the construction of diverse substituted spirocycles. Moreover, the mechanisms for the oxidative ipso-annulation of N-arylpropiolamides were also discussed.

关键词： radical oxidative ipso-annulation N-arylpropiolamides aryl alkynoates azaspiro[4 5]trienones

The cycloaddition reaction using visible light photoredox catalysis

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Science China Chemistry 2016年第2期59卷 161-170页

作者： Yu Liu renjie Song Jinheng Li Department of Chemistry and Chemical Engineering Hunan Institute of Science and TechnologyYueyang 414005China State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineer ingHunan UniversityChangsha 410082China

In recent years, visible light photoredox catalysis has emerged as an important research area in synthesis. In this review, we describe the recent progress in the visible light induced cycloaddition reactions, including [2+2], [3+2], [4+2] and [2+2+2] cycloadditions, for the construction of four-, five- or six-membered cycles and polycycles. Furthermore, the mechanisms for these transformations are also discussed, in which the formation of the radicals is initiated by a visible light photoredox catalysis process.

关键词： cycloaddition annulation visible light photoredox

铝离子絮凝剂对微生物加固砂土效果的影响试验研究

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土木与环境工程学报（中英文） 2025年第1期47卷 71-79页

作者：卫仁杰彭劼许鹏旭李亮亮河海大学岩土力学与堤坝工程教育部重点实验室南京210098

灌注次数过多制约了微生物诱导碳酸钙沉积(MICP)在实际工程中的应用。为了减少灌注次数、提高胶结效率,提出一种MICP加固强化方法,即在胶结液中添加铝离子絮凝剂,以提高MICP加固速率和增强加固效果。开展MICP砂柱试验,在胶结液中加入不... 详细信息

灌注次数过多制约了微生物诱导碳酸钙沉积(MICP)在实际工程中的应用。为了减少灌注次数、提高胶结效率,提出一种MICP加固强化方法,即在胶结液中添加铝离子絮凝剂,以提高MICP加固速率和增强加固效果。开展MICP砂柱试验,在胶结液中加入不同浓度AlCl3·6H2O进行灌注试验,然后测试加固砂柱碳酸钙含量及无侧限抗压强度(UCS)。在水溶液试验中,观察不同溶液条件下沉积物生成情况及溶液的pH值变化,并通过XRD、SEM试验研究铝离子絮凝剂对沉积碳酸钙的成分及形态的影响。结果表明:与常规方法的对照组比较,胶结液中加入适量铝离子絮凝剂,灌注3次后砂柱即可形成有强度的固结体,灌注5次后砂柱无侧限抗压强度可达到1.7MPa,而常规对照组达到相同的强度需要灌注9次。铝离子絮凝剂的掺入有效减少了MICP灌注处理次数,对实际应用有重要意义。

关键词：微生物诱导碳酸钙沉淀铝离子絮凝剂无侧限抗压强度砂土加固

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A Deep Reinforcement Learning-Based Power Control Scheme for the 5G Wireless Systems

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China Communications 2023年第10期20卷 109-119页

作者： renjie Liang Haiyang Lyu Jiancun Fan School of Electronic and Information Engineering Xi’an Jiaotong UniversityXi’anShaanxi 710049China School of Cyber Science and Engineering Xi’an Jiaotong UniversityXi’anShaanxi 710049China

In the fifth generation(5G)wireless system,a closed-loop power control(CLPC)scheme based on deep Q learning network(DQN)is introduced to intelligently adjust the transmit power of the base station(BS),which can improve the user equipment(UE)received signal to interference plus noise ratio(SINR)to a target threshold ***,the selected power control(PC)action in DQN is not accurately matched the fluctuations of the wireless *** the experience replay characteristic of the conventional DQN scheme leads to a possibility of insufficient training in the target deep neural network(DNN).As a result,the Q-value of the sub-optimal PC action exceed the optimal *** solve this problem,we propose the improved DQN *** the proposed scheme,we add an additional DNN to the conventional DQN,and set a shorter training interval to speed up the training of the DNN in order to fully train ***,the proposed scheme can ensure that the Q value of the optimal action remains *** multiple episodes of training,the proposed scheme can generate more accurate PC actions to match the fluctuations of the wireless *** a result,the UE received SINR can achieve the target threshold range faster and keep more *** simulation results prove that the proposed scheme outperforms the conventional schemes.

关键词： reinforcement learning closed-loop power control(CLPC) signal-to-interference-plusnoise ratio(SINR)

Numerical Study of Pipeline Distribution Effect on the Performance of Pasty Propellant Rocket Motor

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Space(Science & Technology) 2023年第1期3卷 572-584页

作者： renjie Hu Weizong Wang Advanced Space Propulsion and Energy Laboratory(ASPEL) School of AstronauticsBeihang UniversityBeijingChina Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies Ministry of EducationBeijingChina Aircraft and Propulsion Laboratory Ningbo Institute of TechnologyBeihang UniversityNingboChina

This paper reports the numerical research on PPRM(pasty propellant rocket motor)through computational fluid dynamics simulation along with pipeline design comparison based on simulation *** structure of PPRM includes feed pipelines,and the propellant is distributed in a cone shape when burnt steadily in the combustion *** a result,the internal flow field presents strong 3-dimensional characteristics,which may lead to the flow *** accurately understand the combustion flow field and flow instability in the PPRM,a numerical simulation of the combustion chamber considering propellant pyrolysis and chemical reaction,coupled with the feed system module,is employed in the *** effect of pipeline distribution,including the pipeline location and the nonuniformity of pipeline diameter on the internal combustion flow characteristics as well as the motor thrust,was *** results show that the vortex caused by the special conical shape of the burning surface leads to pressure *** adjusting the pipeline location and the nonuniformity of pipeline diameter,the distribution of vortex varies dramatically,which leads to different oscillation frequencies and *** some pipeline distribution schemes,there is almost no large vortex in the rocket motor,which greatly eliminates the flow acoustic coupling oscillation of the *** oscillation amplitude decreases from about 5.7%to less than 0.1%.The results will help guide the design of the high-performance feed system and combustion chamber of PPRM.

关键词： vortex oscillation eliminate