基于时域模型的车轮随机动载特性仿真分析     

侯占峰 《拖拉机与农用运输车》2010,37(6)

作为随机过程的车辆道路不平度,通用的模拟方法是频域模型,但在对人-车-路系统进行非线性动力学分析研究时,必须获得关于道路的时域模型。本文描述了两种基于路面功率谱模型的道路时域模型重构方法,利用该方法对C级公路路面进行数值模拟,同时建立了汽车的两自由度模型,应用SIMULINK软件仿真分析了车轮的随机动载特性,结果表明分形模型与路面的实际情况接近。  相似文献   

不平整路面履带车辆动力传动系统扭转随机激励研究   总被引：3，自引：0，他引：3  

刘辉  符升平  项昌乐 《农业机械学报》2010,41(12):1-6

为计算分析履带车辆传动系统扭转随机激励,以标准路面不平度统计特征为基础,实现路面激励时频转换。同时分析扭转随机激励产生机理,提出其理论计算公式,并且通过对相关部件模型的数学抽象,建立不同路面下履带整车动力学模型。通过实例仿真得到某履带车辆扭转随机激励谱,探讨了路面不平度、车速和预张紧力对其产生的影响。研究结果表明,路面不平度和车速是影响扭转随机激励的主要因素。  相似文献   

Negotiating China's rise: The dynamics of Chinese business associations and the Belt and Road Initiative in Brunei Darussalam     

Chang-Yau Hoon  Kaili Zhao 《Asia Pacific viewpoint》2023,64(3):359-370

With an increasingly assertive China and the intensifying influence of the Sinocentre, Chinese overseas who have access to Chineseness can exercise their agentic power in using their cultural capital for economic gains. Beijing has recognised the potential for diasporic Chinese entrepreneurs to contribute to the Belt and Road Initiative (BRI) given their influence in Southeast Asia's economy. Correspondingly, these entrepreneurs hail the BRI as a strategic opportunity for them to turn their cultural capital into fiscal capital. Considering the increased global connectivity and new Chinese migration geographies led by the BRI, this article examines the case of Chinese business associations in Brunei Darussalam. The heterogenous responses of these ethnic Chinese and their associations to China and the BRI attest to the multiplicity and contestations of Chineseness based on different migration histories and sentiments to their ancestral land. We focus on the dynamics between the old Chinese Bruneian business elites and the more recent Chinese business migrants from Malaysia and China. An investigation of the cultural and economic politics within the Chinese Bruneian business community will provide insights into the modality of Chineseness as an economic asset that can be tactically used by diasporic Chinese entrepreneurs to maintain their social position and to respond to China's economic rise.  相似文献   

基于一带一路视角下营口地区现代物流业发展对策研究     

曹军  陈兴霞  邱学林 《辽宁农业职业技术学院学报》2021,23(2)

随着我国"一带一路"战略的进一步实施,营口作为国家物流枢纽建设城市,必然对其物流业发展提出更高的要求,同时也会带来了新的机遇。在深入分析营口地区物流发展现状与问题的基础上,提出了营口地区现代物流业发展相关对策与建议。  相似文献   

我国与东盟国家民事司法协助的缺陷与完善——基于“一带一路”国际合作背景     

李学鹏 《安徽农业大学学报》2018,27(2):89-93

在“一带一路”国际合作背景下,中国与东盟国家经济交流不可避免产生法律冲突,就需要司法权介入。而司法权具有属地性,任何一国的司法机关,其司法权的行使只能限于本国境内,否则就可能侵犯外国主权,因此,只有加强中国与东盟各国司法机关之间的通力合作,相互提供司法协助便利,才能高效快捷地解决国际民事交往中出现的各类案件,从而有效解决争端,促进经济可持续发展。中国与东盟国家民事司法协助应当坚持国家主权原则、平等互惠原则、保护合法权益原则和国际合作原则。鉴于我国与东盟国家民事司法协助存在的诸多问题：现存的司法协助条约自身存在不足,中国与东盟自由贸易区组织形态和法律机制的限制,司法协助途径复杂,应当从域外送达、域外调查取证、外国法院民事判决和仲裁裁决的承认与执行等方面入手,加以规制和解决。  相似文献   

商丘市道路绿化现状与分析     

杨静  李振山 《安徽农业科学》2016,(10)

为做好商丘市树种规划与选择,笔者对商丘市城市道路绿化现状进行调查。结果表明,商丘市道路绿化中栽植的植物共167种(包括12个品种及变种),隶属42科,城区中的15条道路,整体配置模式有一板二带式、二板三带式、三板四带式,四板五带式,共有行道树树种15个,分车带绿化植物约有72种。研究分析了商丘市区道路绿化的现状及存在的问题,在此基础上提出了商丘市城市道路绿化的发展对策。  相似文献   

黄土高塬沟壑区道路排水沟侵蚀产沙试验   总被引：1，自引：0，他引：1  

朱宝才  黄鹏飞  王文龙  史倩华  白芸  李艳富  李垚林 《草地学报》2015,23(5):978-982

为给黄土高塬沟壑区道路排水沟水土流失测算及其防护提供科学依据,采用野外原位放水冲刷试验方法,在放水流量10~50 L·min^-1和坡度4°~10°条件下,对土质道路裸露排水沟和植被排水沟的侵蚀产沙规律进行试验研究。结果表明:放水流量和坡度增大,裸露和植被排水沟的径流含沙量和土壤剥蚀率均成倍数增大,与放水流量呈显著指数函数关系;同一试验条件下,裸露排水沟的径流含沙量和土壤剥蚀率分别是植被排水沟的1.3~1.7倍和1.4~2.2倍。放水流量和坡度对裸露排水沟径流含沙量的影响较为接近,而植被排水沟径流含沙量主要受放水流量影响;不论裸露还是植被排水沟,放水流量对土壤剥蚀率的影响都远大于坡度。  相似文献   

Water in the Mogao Grottoes,China: where it comes from and how it is driven     

HongShou LI  WanFu WANG  HongTao ZHAN  Fei QIU  QingLin GUO  GuoBin ZHANG 《干旱区科学》2015,7(1):37-45

The Dunhuang Mogao Grottoes in China was designated as a world heritage site by UNESCO in 1987 and is famous for its cultural relics. Water is the most active factor that harms the relics in the caves as it damages the grotto murals and painted sculptures. Thus, determining the water sources and driving forces of water movement is a key issue for protecting these cultural relics. These issues have troubled relics protectors for a long time. In this study, the authors chose a representative cave in the Mogao Grottoes and, by completely sealing the cave to make a closed system, measured the water vapor from the surrounding rock. This was accomplished by installing a condensation–dehumidification temperature–humidity control system for the collection of water vapor. The results show that there is continuous evaporation from the deep surrounding rock into the cave. The daily evaporation capacity is determined to be 1.02 g/(d?m2). The water sources and driving forces of water movement were further analyzed according to the character of the water evaporation and by monitoring the temperature and humidity of the surrounding rock. It was found that the water vapor in the cave derives from phreatic water. Moreover, the yearly fluctuation of temperature in the surrounding rock and geothermal forces are the basic powers responsible for driving phreatic evaporation. Under the action of the yearly temperature fluctuations, decomposition and combination of bound water acts as a "pump" that drives phreatic water migration and evaporation. When the temperature rises, bound water decomposes and evaporates; and when it falls, the rock absorbs moisture. This causes the phreatic water to move from deep regions to shallow ones. Determining the source and dynamic foundation of the water provides a firm scientific basis for protecting the valuable cultural relics in the caves.  相似文献   

Food habits of striped hyena(Hyaena hyaena) in a semi-arid conservation area of India     

M Shamshad ALAM 《干旱区科学》2015,7(6):860-866

Striped hyena(Hyaena hyaena) is a near-threatened large carnivore known to occur in arid and semi-arid landscapes in many parts of the world. Its population is declining globally and ecological information is required urgently to meet their conservation needs. We studied the diet pattern of the striped hyena in the semi-arid Gir National Park and Sanctuary(GNPS), western India. Prey items eaten by the striped hyena were identified from scats. Around 44.4% scats represented single to three mammalian preys while 55.6% of them represented four preys to seven preys. A variety of food items were identified including mammals, birds, insects and vegetable matters. Scats analysis showed that 63.91% diet of striped hyena was contributed by wild prey items, 20.94% by domestic prey and 3.31% by birds, whereas vegetable and insects contributed 9.92% and 1.93%, respectively. Diet diversity of the striped hyena computed by the Shannon-Weiner Index(H) was found to be 2.64. The presence of domestic mammals in the scat remains implied that the striped hyena might frequently visit human habitation in search for food and hence, a potential conflict between human and wildlife might arise. Reducing the dependence of hyena on domestic livestock is a challenge to ensure the survival of striped hyena outside the protected area.  相似文献   

"太行山道路"与大学精神   总被引：8，自引：2，他引：6  

谢帆  徐敏云  翟广运  郭洪生 《河北农业大学学报(农林教育版)》2005,7(2):24-26

通过对太行山道路的实践总结,阐述了太行山道路与太行山精神形成的历史背景和深刻内涵。指出太行山精神的实质是体现河北农业大学办学特色和彰显河北农业大学个性的大学精神。坚持太行山道路与保持办学特色、增强核心竞争力是内在统一的。提出应继续弘扬太行山精神,不断强化学校独特的精神品格。  相似文献