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3rd International Academic Exchange Conference on Science and Technology Innovation, IAECST 2021

作者： Zhou, Chao Guo, Danyang Li, Jiaqi Rong, Aiqiong liang, Sihua Lin, xuwen Guangzhou City University of Technology College of Mechanical Engineering Guang Zhou510800 China

ISBN: (纸本)9781665402675

This paper conducts scientific research on the joint scheduling of vehicles and personnel based on the distribution of car-sharing use[1], so as to propose an optimal control scheduling scheme that improves car utilization while making customers more satisfied and maximizing corporate profits. To begin with, we used the partitioning method to pre-processing the shared vehicle location data set, and use Excel software to disassemble the coordinate information. We need to divide the data according to the parking points, count the data according to different parking points, make descriptive statistics on the total number of parked vehicles at the parking points, and then analyze the use distribution of car-sharing[2]. Additionally, a joint car-sharing scheduling optimization model is built and the model is improved, which is then transformed into a two-layer mTSP model[3]. The upper model is an mTSP model with uncertain number of vehicles with time windows, while the lower model is an mTSP model with uncertain number of persons with time windows. At the same time, the genetic algorithm is used to solve the model, and after the operation of selection, cross over and variation combined with the simulated annealing strategy[4] to achieve better optimization results and construct the most beneficial scheduling solution for the enterprise. © 2021 IEEE.

关键词： Genetic algorithms

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Theoretical and experimental study on vibration sensitivity of cubic cavity for space applications

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OPTICS AND LASER TECHNOLOGY 2023年第PartA期158卷

作者： Chen, Long Hu, xuwen Han, liang Xu, Guanjun Liu, Lei Li, Yang Liu, Tao Dong, Ruifang Zhang, Shougang Chinese Acad Sci Natl Time Serv Ctr Xian 710600 Peoples R China Northwestern Polytech Univ Sch Astronaut Xian 710072 Peoples R China Chinese Acad Sci Key Lab Time & Frequency Stand Xian 710600 Peoples R China

The increasing performance of ultra-stable lasers has made them attractive for non-laboratory and space field applications. How to reduce the vibration sensitivity of the optical reference cavity is one of the key points. To develop vibration-insensitive cavity for space applications, we investigate the vibration sensitivity of a cubic cavity with the length of 100 mm theoretically and experimentally. The functional expression of the fractional length change of the cubic cavity versus the cutting depth of the cubic spacer vertices and the compressive forces is presented for the first time. The vibration sensitivity of the 100 mm cubic cavity is measured as low as 2 x 10-11/g. Based on the vibration-insensitive cubic cavity, a 1 Hz-linewidth laser system with an envelope size of 450 mm x 541 mm x 598 mm is developed, which would be the prototype for space applications.

关键词： Vibration sensitivity Cubic cavity Ultra-stable laser

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The Pararectus approach in acetabular fractures treatment: functional and radiologcial results

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BMC MUSCULOSKELETAL DISORDERS 2022年第1期23卷 370-370页

作者： Liu, Guoming Chen, Jinli liang, Chengzhi Zhang, Chengdong Li, xuwen Hu, Yanling Qingdao Univ Dept Orthoped Affiliated Hosp Qingdao 266003 Shandong Peoples R China

Background The surgical treatment of complex acetabular fractures is one of the most challenging procedures for orthopedic surgeons. The Pararectus approach, as a reasonable alternative to the existing surgical procedures, was performed for the treatment of acetabular fractures involving the anterior column. This study aimed to evaluate outcome using the Pararectus approach for acetabular fractures involving anterior columns. Methods Thirty-seven with displaced acetabular fractures involving anterior columns were treated between July 2016 and October 2019 using the Pararectus approach. The functional outcomes (using the Merle d Aubigne and Postel scoring system, WOMAC and modified Harris scoring), the quality of surgical reduction (using the Matta criteria), and postoperative complications were assessed during approximately 26 months follow-up period. Results Thirty-seven patients (mean age 53 years, range: 30-71;28 male) underwent surgery. Mean intraoperative blood loss was 840 ml (rang: 400-2000 ml) and mean operating time was 210 min (rang: 140-500 min). The modified Merle d Aubigne score was excellent and good in 27 cases (73%), fair in 6 cases (16%), and poor in 3 cases (11%). The mean score was 88.5 (range:77-96) for the modified Harris Hip scores, and 22 (range:7-35) for the WOMAC scores after operation. Postoperative functional outcomes were significantly improved compared with preoperative outcomes (P < 0.0001). The quality of reduction was anatomical in 21 cases (57%), satisfactory in 9 cases (24%), and unsatisfactory in 7 cases (19%). At follow-up, four patients developed a DVT, and heterotopic bone formation was observed in one patient. The hip osteoarthritis was not observed. Conclusion The Pararectus approach achieved good functional outcomes and anatomical reduction in the treatment of acetabular fractures involving anterior column with minimal access morbidity.

关键词： Acetabular fracture Pararectus approach Surgical exposure Outcome Radiological results

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Environmental Monitoring Technology for Marine Natural Gas Hydrate

Environmental Monitoring Technology for Marine Natural Gas H...

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2023年中国地球科学联合学术年会

作者： liang Qianyong Ye Jianliang Qin xuwen Dong Yifei Xie Wenwei Zhong Chao Guo Binbin Guangzhou Marine Geological Survey China Geological Survey

Natural gas hydrate(NGH) is considered as one of the new clean energy sources of the 21st century with the highest potential. The environmental issues of NGH production have attracted the close attention of scientists in various countries. In 2017 and 2020, China Geological Survey successfully organized two rounds of NGH production test in the South China Sea, which set a number of world records, marking a significant leap from "exploratory test production" to "experimental test production", and also indicating an important breakthrough in environmental safety of NGH production test. China Geological survey attaches great importance to the environmental impact of NGH research work. Since 2011, we have research methane leakage, underwater landslides, subsidence, and marine ecological change may cause by NGH exploration. And the marine environment baseline characteristics before the production test in Shenhu sea area have been clarified. In addition, environmental security has also been effectively guaranteed via a comprehensive environmental monitoring system built during the NGH production test. The monitoring system considered methane leakage, seabed subsidence, marine environment and sea surface atmosphere environment. The whole process was monitored via multiple means, in multiple layers, in all domains, and in real time. After the production test, the marine environment tracking survey have been carried out in time to effectively discuss and verify the environmental impact of NGH production test. The results of the two rounds of NGH production test showed that the content of dissolved methane in seawater and the seabed environment characteristics is consistent with the background values, indicating that the two rounds of production test did not cause seabed landslide, methane leakage and other environmental problems, and make no difference on the marine environment basically.

关键词： Natural gas hydrates Production test Environmental monitoring Environmental impact

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Substitution or complementary effects between hosts and neighbors? information disclosure: Evidence from Airbnb

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JOURNAL OF BUSINESS RESEARCH 2023年 161卷

作者： Zheng, Zuolong Li, Ziying Zhang, xuwen liang, Sai Law, Rob Lei, Jiasu Suzhou Univ Sci & Technol Sch Business 99 Xuefu Rd Suzhou Peoples R China Tsinghua Univ Sch Econ & Management 30 Shuangqing Rd Beijing Peoples R China Nankai Univ Coll Tourism & Serv Management 38 Tongyan Rd Tianjin 300350 Peoples R China Univ Macau Asia Pacific Acad Econ & Management Fac Business Adm Dept Integrated Resort & Tourism Management Macau Peoples R China

Prior studies have attributed and confirmed the importance of hosts' information disclosure on boosting their performance due to the prominent information asymmetry on peer-to-peer rental platforms. This study takes a step further by analyzing how hosts and neighbors' disclosure of descriptions simultaneously and interactively influences the review volume and performance of Airbnb listings. Based on a panel dataset and fixed effect regression models, the results confirmed the findings of prior studies that self-disclosure of descriptions has a positive effect on the review volume and performance. We also initially find a substitute effect between self -disclosure of descriptions and neighbors' disclosure of public information, with a complementary effect be-tween self-disclosure of descriptions and neighbors' disclosure of private information. As a novel attempt to analyze the effect of neighbors' information disclosure on property performance, this study provides important implications for relevant literature and for hospitality professionals to improve information disclosure strategies.

关键词： Information disclosure Neighborhood effect Knowledge sharing Online review Sharing economy Airbnb

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Evaluation of Efficiency Enhancement for a Solar Panel Using Water, Ice and Dry Ice Backside Cooling Systems

Evaluation of Efficiency Enhancement for a Solar Panel Using...

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International Electrical Engineering Congress (iEECON)

作者： Tawinwika Chaisuwan Shuguang Wei Banri Khemkladmuk Supasin Srisombat Raohuai liang xuwen Zheng Aisawan Chanwiset Krit Lertlam Chonlatee Photong Faculty of Engineering Mahasarakham University Maha Sarakham Thailand School of Physics and Electronics Nanning Normal University Guangxi China

ISBN: (数字)9798350383591

ISBN: (纸本)9798350383607

The purpose of this research is to study and conduct an experimental test for investigating the increase of efficiency of a solar panel when cooling it with a backside cooling system. There were 3 experiment test-rigs by using 3 different refrigerants: water, ice, and dry ice. By containing a type of refrigerant into its identical box that was designed by wrapping insulation around the box while drilling the holes for the box that did not contain any refrigerant. Then covered the box with a solar panel. To determine which refrigerant could be the best helped increase the efficiency of a solar panel. The research team conducted the tests with 2 time periods: a short time for 1 hour operation when collecting experimental results for every 2 minutes and a long time for 6 hours when collecting experimental results every 10 minutes. It is found from the experimental tests that significantly different capacity in power generated for different types of refrigerants could be obviously noticed even for the short time. For the long-time test, ice was the best refrigerant that continuously enhanced the efficiency for the solar panel with 25.2 watts compared with 24.0 watts for no refrigerant cooling, which was 6.25% increase.

关键词： Electrical engineering Drilling Insulation Cooling Ice Solar panels Wrapping

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Effects of the seepage capability of overlying and underlying strata of marine hydrate system on depressurization-induced hydrate production behaviors by horizontal well

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MARINE AND PETROLEUM GEOLOGY 2021年 128卷 105019-105019页

作者： Yang, Lin Ye, Jianliang Qin, xuwen liang, Qianyong Wu, Xuemin China Geol Survey Guangzhou Marine Geol Survey Guangzhou 510075 Peoples R China China Geol Survey Gas Hydrate Engn Technol Ctr Guangzhou 510075 Peoples R China China Geol Survey Beijing 100083 Peoples R China

Marine gas hydrates mostly occur in high-water content and non-diagenetic submarine sediments without tight stratigraphic traps. Therefore, the seepage capability of overlying and underlying strata (OUS) serves as a crucial parameter to analyze hydrate production behaviors. This study focuses on the numerical simulation study on the effects of the seepage capability of OUS on hydrate production behaviors in depressurization-induced production of three-phase hydrate deposits using a horizontal well. As shown by the simulation results, in the early stage of hydrate production, the permeability of the OUS had little effects on gas production rates. In long-term hydrate production, the hydrate deposit with lower permeability OUS has higher cumulative gas production, larger gaswater ratio and hydrate dissociation scope, and less cumulative water production. Moreover, the hydrate production efficiency first decreased rapidly and then tended to be stable as the permeability of OUS increased, and hydrate production behaviors are similar while the permeability of OUS larger than 1.0 mD. Herein, a waterresisting layers were constructed in overlying and/or underlying strata to decrease the seepage capability of OUS. Compared to the original hydrate deposits, the cumulative gas production and gas-water ratio increased by 31% and 147%, respectively but the water production was only 76% on the 5th year of the simulated production in which water-resisting layers were designed. Furthermore, the water-resisting layer in underlying strata produced more significant effects on hydrate production efficiency than the layer in overlying strata. All these indicate that the low-permeability OUS (especially in underlying strata) can restrain fluid invading into hydrate reservoirs, increase the pressure gradient of hydrate reservoirs and significantly improve the hydrate production efficiency during long-term hydrate production. Therefore, water-proof reformation in OUS may be an effective me

关键词： Marine gas hydrate Seepage capability Water-resisting layer Horizontal well Depressurization

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The inbound container space allocation in the automated container terminals

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EXPERT SYSTEMS WITH APPLICATIONS 2021年 179卷 115014-115014页

作者： Yu, Mingzhu liang, Zhuobin Teng, Yi Zhang, Zizhen Cong, xuwen Shenzhen Univ Coll Management Inst Big Data Intelligent Management & Decis Shenzhen 518060 Peoples R China Shenzhen Univ Coll Civil & Transportat Engn Shenzhen 518060 Peoples R China Guangdong Univ Educ Dept Comp Sci Guangzhou 510303 Peoples R China Sun Yat Sen Univ Sch Data & Comp Sci Guangzhou 510006 Peoples R China

In this paper, we study an inbound container space allocation problem in the automated container terminals using simulation-embedded optimization. We aim to allocate the container terminal yard space for a batch of arrived inbound containers so as to minimize the total AGV (Automated Guided Vehicle) waiting time in the space allocation process and the external truck waiting time in the future container retrieval process. We propose an integer programming model to characterize the problem and prove the NP-hardness of the problem. A simulation module is employed to estimate the container rehandle number happened in the retrieval process. A simulation-embedded genetic algorithm is developed to solve the problem. Numerical experiment results show that (1) The proposed algorithm can significantly affect the performance of the allocation decision and achieve a trade-off between fast computation and good solution quality. (2) The space allocation schemes of the inbound containers are affected by different factors, such as initial block layout, quantity of arriving containers, and containers' arriving information. (3) The automated container terminal operators who care about the external truck waiting time may consider the simulation-embedded approach when the block yard is congested.

关键词： Automated container terminal Inbound container Space allocation problem Simulation-embedded optimization

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中国南海天然气水合物开采储层水合物相变与渗流机理:综述与展望

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中国地质 2022年第3期49卷 749-769页

作者：秦绪文陆程王平康梁前勇中国地质调查局北京100037 中国地质调查局广州海洋地质调查局广东广州510075 天然气水合物勘查开发国家工程研究中心广东广州510075 中国地质调查局油气资源调查中心北京100083

【研究目的】中国地质调查局先后于2017年、2020年在南海北部神狐海域成功实施两轮水合物试采,创造了产气时间最长、产气总量最大、日均产气量最高等多项世界纪录,了解和掌握南海天然气水合物开采储层相变与渗流机理,有助于进一步揭示... 详细信息

【研究目的】中国地质调查局先后于2017年、2020年在南海北部神狐海域成功实施两轮水合物试采,创造了产气时间最长、产气总量最大、日均产气量最高等多项世界纪录,了解和掌握南海天然气水合物开采储层相变与渗流机理,有助于进一步揭示该类型水合物分解机理、产出规律、增产机制等,可为中国海域水合物资源规模高效开采提供理论基础。【研究方法】基于两轮试采实践,笔者通过深入研究发现,储层结构表征、水合物相变、多相渗流与增渗、产能模拟与调控是制约水合物分解产气效率的重要因素。【研究结果】研究表明,南海水合物相变具有分解温度低,易在储层内形成二次水合物等特点,是由渗流场-应力场-温度场-化学场共同作用的复杂系统;多相渗流作用主要受控于未固结储层的物性特征、水合物相变、开采方式等多元因素影响,具有较强的甲烷吸附性、绝对渗透率易突变、气相流动能力弱等特点;围绕南海水合物长期、稳定、高效开采目标,需要在初始储层改造基础上,通过实施储层二次改造,进一步优化提高储层渗流能力,实现增渗扩产目的。【结论】随着天然气水合物产业化进程不断向前推进,还需要着力解决大规模长时间产气过程中温度压力微观变化及物质能源交换响应机制以及水合物高效分解、二次生成边界条件等难题。

关键词：天然气水合物泥质粉砂储层水合物相变渗流机理海域天然气水合物勘查试采工程南海中国

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Orbital reference frame estimation with power spectral density constraints for drag-free satellites

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Chinese Journal of Aeronautics 2016年第6期29卷 1721-1729页

作者： Zhang Yonghe Wang Yamin Mao Qingyun liang xuwen Shanghai Institute of Microsystem and Information Technology Chinese Academy of SciencesShanghai 200050China Shanghai Engineering Centre for Microsatellites Shanghai 201210China Joint Key Laboratory of Microsatellite Chinese Academy of SciencesShanghai 201210China

The drag-free satellites are widely used in the field of fundamental science as they enable the high-precision measurement in pure gravity fields. This paper investigates the estimation of local orbital reference frame(LORF) for drag-free satellites. An approach, taking account of the combination of the minimum estimation error and power spectral density(PSD) constraint in frequency domain, is proposed. Firstly, the relationship between eigenvalues of estimator and transfer function is built to analyze the suppression and amplification effect on input signals and obtain the eigenvalue range. Secondly, an optimization model for state estimator design with minimum estimation error in time domain and PSD constraint in frequency domain is established. It is solved by the sequential quadratic programming(SQP) algorithm. Finally, the orbital reference frame estimation of low-earth-orbit satellite is taken as an example, and the estimator of minimum variance with PSD constraint is designed and analyzed using the method proposed in this paper.

关键词： Drag-free satellite Orbital reference frame Power spectral density State estimation Transfer function

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