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Plume aerodynamic effects of cushion engine in lunar landing

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Chinese Journal of Aeronautics 2013年第2期26卷 269-278页

作者： he Bijiao he xiaoying Zhang Mingxing Cai Guobiao School of Astronautics Beihang University

During the second period of China ＂Tanyue＂ Project, the explorer will softland on the moon. The cushion engines are used to decelerate the explorer and reduce the impact on the lunar ground. It is necessary to study its plume effects on the explorer component. The self-developed PWS （Plume WorkStation） software based on direct simulation Monte Carlo （DSMC） method is used to simulate the plume effects of two 150 N engines. Due to the complex structure of the explorer, PWS uses a decoupling method to treat the boundary mesh, which mainly interacts with simulation particles, and has no relation with the computational grids. After the analytical expressions of plane surfaces and curved surfaces of each boundary block are given, the particle position within or without the boundary blocks can be easily determined. Finally the 3D plume field of two 150 N engines is simulated. The pressure, temperature and velocity distributions of plume field are clearly presented by three characteristic slices. The aerodynamic effects on the explorer bottom, the landfall legs and antenna are separately shown. The compression influence on the plume flow of four landfall legs can be observed.

关键词： Boundary blocks Cushion engines Lunar landing Monte Carlo methods Plume effects

Simulation of two-phase plume field of liquid thruster

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Science China(Technological Sciences) 2012年第6期55卷 1739-1748页

作者： he xiaoying he BiJiao CAI GuoBiao School of Astronautics Beihang UniversityBeijing 100191China

When the liquid propellant thruster works,its plume field would contain many propellant liquid droplets,especially at pulse state.Liquid droplets may move along with the gas flow and deposit on the components of spacecraft as contamination.The simulation of the plume field involving the gas molecules and liquid droplets is an important part in contamination studies of thruster plume.Based on the PWS software developed by Beihang University(BUAA),axial-symmetric two-phase direct simulation Monte Carlo(DSMC) method is used with the liquid droplet taken as a kind of solid particle.The computation of gas-to-particle effect and gas reflection on the particle surface are decoupled.The inter-particle collision is also considered.The gas parameters at nozzle exit of 120N engine after 20 ms pulse work are taken as the entrance condition of the numerical simulation.Four test cases are conducted for comparison of different collision modules.Simulation results show that the effects of liquid propellant droplets mainly concentrate near the axis line of engine.The particle-to-gas collision would cause evident differences in the gas field and subtle differences in the particle phase.The liquid droplets in the plume field are generally accelerated and convected by the gas molecules.The DSMC method is proved to be a feasible solver to numerically simulate the two-phase flow involving solid phase and rarefied gas flow.

关键词：羽流污染液体火箭仿真结果推进器北京航空航天大学 DSMC方法发动机推力气体分子

Extension of the low diffusion particle method for near-continuum two-phase flow simulations

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Chinese Journal of Aeronautics 2013年第1期26卷 37-46页

作者： Su Wei he xiaoying Cai Guobiao School of Astronautics Beihang University

The low diffusion （LD） particle method, proposed by Burt and Boyd, is modified for the near-continuum two-phase flow simulations. The LD method has the advantages of easily coupling with the direct simulation Monte Carlo （DSMC） method for multi-scale flow simulations and dramatically reducing the numerical diffusion error and statistical scatter of the equilibrium particle methods. Liquidor solid-phase particles are introduced in the LD method. Their velocity and temperature updating are respectively, calculated from the motion equation and the temperature equation according to the local gas properties. Coupling effects from condensed phase to gas phase are modeled as momentum and energy sources, which are respectively, equal to the negative values of the total momentum and energy increase in liquid or solid phase. The modified method is compared with theoretical results for unsteady flows, and good agreements are obtained to indicate the reliability of the one-way gas-to-particle coupling models. Hybrid LD-DSMC algorithm is implemented and performed for nozzle discharging gas-liquid flow to show the prospect of the LD-DSMC scheme for multi-scale two-phase flow simulations.

关键词： DSMC method Hybrid simulation Low diffusion particle method Motion relaxation Temperature relaxation Two-phase flow

Optioning Water Rights:A Potential Alternative to the Hanjiang-Weihe River Water Transfer Project,China

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Chinese Geographical Science 2020年第6期30卷 1039-1051页

作者： he xiaoying KANG Hong GU Yaopeng SONG Yuanliang School of Management and Economics Xi'an Technological UniversityXi'an 710021China Zhongguancun Listed Companies Association Beijing 100011China

China has started shifting from relying on supply management to demand management strategy in addressing its water shortage problems.Water option,a financial derivative for water commodity,has been utilized to manage water demands in the United States and Europe since the 1990 s but is still novel to China.In this study we analyzed the pros and cons of China’s existing system for water rights transfers and proposed an alternative,flexible trading instrument-water options for China.Incorporating the uncertainty to water option pricing,this study first conducted an empirical analysis of the water option in the water-receiving area of the Hanjiang-Weihe River Transfer Project of China,and then evaluated the benefits of the water option applications.Results show that water option trading can bring water cost saving and increase the potential industrially added value for industrial enterprises in the receiving area,and trading of short-and-medium term water options is more favorable than the long-term water options trading.The novel water option trading proposed in this study,once verified through pilot studies,will be helpful in addressing water shortage problems in China.

关键词： water shortage demand management water rights transfer water options water diversion project

基于SPME-GC-MS分析稻谷遭受4种霉菌浸染期间挥发性物质成分的变化

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中国粮油学报 2024年第5期39卷 172-180页

作者：和肖营沈玲意吕冲都立辉中储粮江苏质检中心有限公司杭州分公司杭州310000 绿城农科检测技术有限公司2 北京100037 中央储备粮杭州直属库有限公司杭州310000 南京财经大学南京210000

对接种4种不同霉菌的稻谷样品中挥发性物质组分分析,探究其变化规律及特征性挥发性物质。首先,将4株霉菌(灰绿曲霉3.0100、灰绿曲霉3.3975、尖孢镰刀菌PM、尖孢镰刀菌PP)制成2种含量的菌悬液,再将其分别接种在稻谷样品上,于28℃、80%相... 详细信息

对接种4种不同霉菌的稻谷样品中挥发性物质组分分析,探究其变化规律及特征性挥发性物质。首先,将4株霉菌(灰绿曲霉3.0100、灰绿曲霉3.3975、尖孢镰刀菌PM、尖孢镰刀菌PP)制成2种含量的菌悬液,再将其分别接种在稻谷样品上,于28℃、80%相对湿度的恒温培养箱中储藏56 d,每隔7 d用固相微萃取-气质联用技术(SPME-GC-MS)对稻谷样品进行检测,获得定性和定量数据,并进行分析。结果显示接种不同霉菌的稻谷样品在储藏期间产生的挥发性物质主要有烷、烯、醇、酮、醛、酸、酯、芳香族化合物及其他类九大类物质,在储藏不同时间后,产生的挥发性物质种类与含量有较大差异,从中找出了4种霉变稻谷的特征性挥发性物质和在不同污染阶段的变化规律。初步研究表明,通过检测稻谷中的挥发性物质来判断污染霉菌的种类和生长状态的有一定的可行性。

关键词：霉菌稻谷微生物挥发性物质固相微萃取-气质联用技术

基于社会认知理论的老年肺癌患者术后运动管理方案构建

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中国实用护理杂志 2024年第5期40卷 329-337页

作者：胡银燕赵林芳贺晓映浙江大学医学院附属邵逸夫医院胸外科杭州310018 浙江大学医学院附属邵逸夫医院静脉治疗专科杭州310018

目的基于社会认知理论构建老年肺癌患者术后运动管理方案, 为提高老年肺癌患者术后运动能力提供指导。方法系统检索UpToDate、PubMed、Web of Science、Cochrane Library、医脉通、万方、中国知网等数据库中有关老年肺癌患者术后康复运... 详细信息

目的基于社会认知理论构建老年肺癌患者术后运动管理方案, 为提高老年肺癌患者术后运动能力提供指导。方法系统检索UpToDate、PubMed、Web of Science、Cochrane Library、医脉通、万方、中国知网等数据库中有关老年肺癌患者术后康复运动的相关文献, 检索时间为建库至2023年2月13日。以社会认知理论为指导, 在文献研究的基础上初步拟订老年肺癌患者术后运动管理方案初稿, 通过专家会议法修订方案内容后形成终稿。结果专家会议法问卷回收率为12/12;专家权威系数为0.892;各个条目的重要性变异系数为0~0.150, Kendall协调系数为0.262(P<0.01), 最终形成的运动管理方案包含5个一级条目、18个二级条目、42个三级条目。结论老年肺癌术后运动管理方案构建的过程具有科学性和可靠性、内容具有合理性和全面性, 能为提高老年肺癌术后患者运动康复提供指导。

关键词：老年人肺肿瘤社会认知理论运动

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青少年“符号消费”的伦理问题与对策研究

南华大学学报（社会科学版） 2024年第2期25卷 37-42页

作者：何小英朱舒欣南华大学马克思主义学院湖南衡阳421001

随着消费文化的日益多元化和深入,青少年群体中的“符号消费”现象引发了广泛关注。文章旨在深入探讨这一现象背后的伦理问题及其对青少年价值观和消费行为的影响。符号消费不只限于物质产品的购买,更体现在对品牌、形象和社会地位象征... 详细信息

随着消费文化的日益多元化和深入,青少年群体中的“符号消费”现象引发了广泛关注。文章旨在深入探讨这一现象背后的伦理问题及其对青少年价值观和消费行为的影响。符号消费不只限于物质产品的购买,更体现在对品牌、形象和社会地位象征的追求。这种追求往往导致青少年的消费决策偏离理性,忽视真实需求,从而引发伦理问题,如盲目从众、攀比心理的加剧、资源的过度消费以及对个人和社会责任的忽视。这些问题不仅影响青少年的健康成长,还对社会的可持续发展构成威胁。因此,文章着重分析这些伦理问题,并提出相应的对策,目的是促进青少年形成健康的价值观和消费行为,为社会的可持续发展贡献力量。

关键词：符号消费青少年价值观消费伦理

维普期刊数据库博看期刊

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智媒时代泛娱乐主义的生成逻辑与应对理路

马克思主义理论教学与研究 2024年第1期 140-148页

作者：袁芃何晓颖同济大学马克思主义学院

泛娱乐主义与智能媒体相结合,以娱乐作为衡量一切的尺度,过度娱乐、过界娱乐成为现代人的“精神鸦片”。智媒时代泛娱乐主义呈现新的样态:娱乐活动的“无休止”、娱乐内容的“景观狂欢”、娱乐群体“茧房化”。在资本宰制、媒介技术革... 详细信息

泛娱乐主义与智能媒体相结合,以娱乐作为衡量一切的尺度,过度娱乐、过界娱乐成为现代人的“精神鸦片”。智媒时代泛娱乐主义呈现新的样态:娱乐活动的“无休止”、娱乐内容的“景观狂欢”、娱乐群体“茧房化”。在资本宰制、媒介技术革新、个体心理需求等因素的共同驱动下,娱乐的本质被异化,泛娱乐主义在智媒空间肆虐并消解了主流意识形态的引领力和凝聚力,特别是对青年大学生产生了负面影响。对此,社会、媒体、高校应协同发力,从规范娱乐内容、净化媒介环境、提升主体鉴赏能力三个维度,形成破除泛娱乐主义对大学生不良影响的有效路径。

关键词：泛娱乐主义智媒时代生成逻辑应对理路

转盘偏心距对不对中-碰摩转子动力学响应的影响

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机床与液压 2024年第6期52卷 117-123页

作者：张凌云李銮贺晓莹刘忠熊中刚桂林航天工业学院机电工程学院广西桂林541004 桂林航天工业学院广西特种工程装备与控制重点实验室广西桂林541004 福建船政交通职业学院汽车学院福建福州350007

针对含转盘偏心的不对中-碰摩转子系统耦合故障导致的振动问题,建立不对中-碰摩耦合条件下的滑动轴承-转子系统动力学模型,考虑齿式联轴器不对中作用力、滑动轴承油膜力、转盘偏心距和碰摩等一系列强非线性的耦合。基于多参数、多目标... 详细信息

针对含转盘偏心的不对中-碰摩转子系统耦合故障导致的振动问题,建立不对中-碰摩耦合条件下的滑动轴承-转子系统动力学模型,考虑齿式联轴器不对中作用力、滑动轴承油膜力、转盘偏心距和碰摩等一系列强非线性的耦合。基于多参数、多目标协同仿真得到关键参数与系统响应的关联关系,并引入最大碰摩力和电信领域中占空比的概念对转子模型的动力学特性进行量化表征。研究结果表明:不对中的存在导致系统产生了2×、4×等偶数倍频,系统的轴心轨迹呈现出“8”字形,偏心距的变化直接影响了系统的周期运动类型和分布,当偏心距由小变大时,系统的一二阶临界转速显著提高,直接限制了油膜力的响应幅值,但不会影响不对中产生的2×频率幅值。最后得到此模型合理的偏心距取值范围。

关键词：不对中-碰摩油膜力偏心距