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半潜式平台遭遇碰撞后水平位移及锚泊索链张力变化研究
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作者 孟庆辉 李范春 贾德君 《船海工程》 北大核心 2018年第A01期85-91,共7页
为了研究半潜式平台遭遇碰撞后的水平位移以及锚泊索链张力的变化,评估平台锚泊的安全性,提出一种简化外来船只与半潜式平台间碰撞问题的方法,以动量定理为基础,将碰撞平台的外来船只转化为一个瞬时荷载,应用时域响应分析方法,对平台遭... 为了研究半潜式平台遭遇碰撞后的水平位移以及锚泊索链张力的变化,评估平台锚泊的安全性,提出一种简化外来船只与半潜式平台间碰撞问题的方法,以动量定理为基础,将碰撞平台的外来船只转化为一个瞬时荷载,应用时域响应分析方法,对平台遭遇碰撞前后自身水平位移范围的变化进行分析;应用集中质量法计算平台锚泊索链张力最大值,碰撞载荷对索链张力的影响。分析结果表明,外来船只撞击平台时,平台的水平位移以及索链张力均大幅增加,部分索链的安全系数出现下降,接近于1的情况。 展开更多
关键词 半潜式平台 碰撞 水平位移 索链张力 锚泊
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索链式巢门脱粉器制作方法
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作者 李忱 《中国养蜂》 1993年第1期27-28,共2页
近年来,一些蜂场在春季时购进并饲喂带病菌的花粉,使蜂群发生诸如白垩病等一些蜜蜂疾病,给自己的养蜂生产带来不少的麻烦和损失。为了避免发生这种情况,提倡用自己无病的蜂群脱花粉贮备起来喂蜂是很有必要的。它具有安全又省钱的优点。... 近年来,一些蜂场在春季时购进并饲喂带病菌的花粉,使蜂群发生诸如白垩病等一些蜜蜂疾病,给自己的养蜂生产带来不少的麻烦和损失。为了避免发生这种情况,提倡用自己无病的蜂群脱花粉贮备起来喂蜂是很有必要的。它具有安全又省钱的优点。要脱粉就必须有脱粉器,脱粉器可以到蜂具商店购买,也可自己动手制作,本刊将陆续向读者推荐两篇自制脱粉器的制作方法。这两种方法都有制作简单,使用方便、脱粉效果好之优点。尤其适合资金不足的业余或专业养蜂者采用。 展开更多
关键词 索链式巢门 脱粉器 制造 养蜂机具
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连接索链弹性模量对防撞系统能量转换的影响
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作者 陈徐均 于伟 刘俊谊 《交通运输工程学报》 EI CSCD 北大核心 2016年第3期46-54,共9页
为了研究船舶与柔性浮式防撞系统碰撞过程中能量的转换关系,分析了连接索链弹性模量对系统消能作用的影响。在对数值计算模拟条件做出合理假设的前提下,基于能量守恒原理,模拟了船舶撞击柔性浮式防撞系统的运动过程,分析了不同连接索链... 为了研究船舶与柔性浮式防撞系统碰撞过程中能量的转换关系,分析了连接索链弹性模量对系统消能作用的影响。在对数值计算模拟条件做出合理假设的前提下,基于能量守恒原理,模拟了船舶撞击柔性浮式防撞系统的运动过程,分析了不同连接索链弹性模量条件下重力锚位移的变化规律。基于位移相似与能量等量原则,建立了2种数学模型,比较了数值计算结果与试验结果的差异。分析结果表明:连接索链弹性模量衡量了其变形程度,是影响撞击过程中船舶动能转化为弹性势能的重要因素;在相同条件下,连接索链的弹性模量越大,连接索链越不易发生形变,船舶撞击系统过程中转化为弹性势能的动能就越小,转化为重力锚摩擦内能的动能就会越大,各重力锚的锚位移就会越大;通过数值计算结果与模型试验结果的比较,模型试验中连接索链的弹性模量为260GPa比较合适;在保证连接索链不发生断裂的前提下,索链的选取直接影响系统走锚的位移,从而影响柔性浮式防撞系统的拦阻效果。 展开更多
关键词 桥梁工程 防撞系统 连接索链 弹性模量 能量转换 锚位移
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复合缆索锚泊下的Spar平台动态响应分析 被引量:3
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作者 朱克强 黄剑 《港工技术》 2010年第2期5-8,共4页
利用复合索链的计算公式,计算不同配置的复合链组成的锚泊系统的变刚度,并将计算结果运用于Spar平台运动方程中刚度矩阵的修正,分析并比较在不同锚泊系统作用下,Spar平台的动态响应行为。通过计算发现:虽然不同配置的复合缆索对平台的... 利用复合索链的计算公式,计算不同配置的复合链组成的锚泊系统的变刚度,并将计算结果运用于Spar平台运动方程中刚度矩阵的修正,分析并比较在不同锚泊系统作用下,Spar平台的动态响应行为。通过计算发现:虽然不同配置的复合缆索对平台的动态响应没有多大影响,但是缆索张力的变化确实截然不同。这些在平台锚泊系统的初步设计中必须考虑。 展开更多
关键词 SPAR平台 系泊定位系统 索链 复合索链 动力分析
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半潜式平台两种锚泊系统的静力分析与比较 被引量:8
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作者 黄剑 朱克强 《华东船舶工业学院学报》 2004年第3期1-5,共5页
针对目前半潜式平台常用的全索链和复合索链两种定位系统进行了静力计算和比较,重点推导了复合索链的计算公式,利用该公式可以计算带有任意多重块的复合链的状态参数。文中给出了复合链系泊下的半潜式平台的具体计算步骤,并将结果绘制... 针对目前半潜式平台常用的全索链和复合索链两种定位系统进行了静力计算和比较,重点推导了复合索链的计算公式,利用该公式可以计算带有任意多重块的复合链的状态参数。文中给出了复合链系泊下的半潜式平台的具体计算步骤,并将结果绘制成了图谱。 展开更多
关键词 半潜式平台 系泊定位系统 索链 复合索链
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30Mn2钢焊接裂纹的研究 被引量:1
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作者 李平生 许伯藩 张细菊 《热加工工艺》 CSCD 北大核心 2001年第6期47-48,50,共3页
通过对 30 Mn2钢焊接时产生的裂纹进行全面的检验及分析 ,结果表明材质的微量元素控制不当、显微魏氏组织及夹杂物的存在都是造成裂纹的主要因素。
关键词 焊接裂纹 微量元素 魏氏组织 热敏温度 30Mn2钢 船舶 索链
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预应力桥梁悬臂浇筑设计方案研究 被引量:1
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作者 贾彪 《黑龙江科技信息》 2013年第34期239-240,共2页
桥位于南方某沿海城市,方案为现浇预应力混凝土连续梁方案,上部主梁采用挂篮对称悬臂浇筑施工工法。利用过渡墩和中墩基础,在墩旁搭设支架,在支架上现浇0#与1#块并与墩身临时固结,再在两侧对称搭设挂蓝,对称悬臂浇筑剩余梁段并张拉对应... 桥位于南方某沿海城市,方案为现浇预应力混凝土连续梁方案,上部主梁采用挂篮对称悬臂浇筑施工工法。利用过渡墩和中墩基础,在墩旁搭设支架,在支架上现浇0#与1#块并与墩身临时固结,再在两侧对称搭设挂蓝,对称悬臂浇筑剩余梁段并张拉对应梁段的钢索,在边跨搭设支架,在支架上浇筑边跨梁段,先合拢边跨,张拉边跨合拢钢索,再合拢次边跨、中跨,同时张拉对应跨合拢钢索。 展开更多
关键词 预应力 临时固结 预应力索链 独跨合拢
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FAST MUSIC SPECTRUM PEAK SEARCH VIA METROPOLIS-HASTINGS SAMPLER 被引量:5
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作者 Guo Qinghua Liao Guisheng 《Journal of Electronics(China)》 2005年第6期599-604,共6页
A fast MUltiple SIgnal Classification (MUSIC) spectrum peak search algorithm is devised, which regards the power of the MUSIC spectrum function as target distribution up to a constant of proportionality, and uses Metr... A fast MUltiple SIgnal Classification (MUSIC) spectrum peak search algorithm is devised, which regards the power of the MUSIC spectrum function as target distribution up to a constant of proportionality, and uses Metropolis-Hastings (MH) sampler, one of the most popular Markov Chain Monte Carlo (MCMC) techniques, to sample from it. The proposed method reduces greatly the tremendous computation and storage costs in conventional MUSIC techniques i.e., about two and four orders of magnitude in computation and storage costs under the conditions of the experiment in the paper respectively. 展开更多
关键词 MUltiple Signal Classification (MUSIC) algorithm Metropolis-Hastlngs (MH)sampler Markov Chain Monte Carlo (MCMC)
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Approach in High Precision Topic-Specific Resource Discovery on the Web
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作者 YeWei-guo LuZheng-ding 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第1期41-45,共5页
The Internet presents numerous sources of useful information nowadays. However, these resources are drowning under the dynamic Web, so accurate finding user-specific information is very difficult. In this paper we dis... The Internet presents numerous sources of useful information nowadays. However, these resources are drowning under the dynamic Web, so accurate finding user-specific information is very difficult. In this paper we discuss a Semantic Graph Web Search (SGWS) algorithm in topic-specific resource discovery on the Web. This method combines the use of hyperlinks, characteristics of Web graph and semantic term weights. We implement the algorithm to find Chinese medical information from the Internet. Our study showed that it has better precision than traditional IR (Information Retrieval) methods and traditional search engines. Key words HITS - evolution web graph - power law distribution - context analysis CLC number TP 391 - TP 393 Foundation item: Supported by the National High-Performance Computation Fund (00303)Biography: Ye Wei-guo (1970-), male, Ph. D candidate, research direction: Web information mining, network security, artificial intelligence. 展开更多
关键词 HITS evolution web graph power law distribution context analysis
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2-Competition Index of Primitive Digraphs Using Graph Theory 被引量:3
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作者 方炜 高玉斌 李忠善 《Journal of Donghua University(English Edition)》 EI CAS 2014年第3期320-324,共5页
Recently,scrambling index and competition index are widely applied to stochastic matrices and food webs. By analyzing the relationship of scrambling index and 2-competition index,n-「d/2」+ 1 was proved to be an upper... Recently,scrambling index and competition index are widely applied to stochastic matrices and food webs. By analyzing the relationship of scrambling index and 2-competition index,n-「d/2」+ 1 was proved to be an upper bound of the 2-competition2 index of a primitive digraph with exact d loops in this article.Moreover,the maximum index problem and the index set problem for the 2-competition index of primitive digraphs with minimally strong digraphs were settled. 展开更多
关键词 2-competition index primitive digraphs minimally strong digraphs
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Elastic catenary cable element considering frictional slip effect 被引量:10
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作者 CAI JianGuo LIM James +2 位作者 FENG Jian XU YiXiang WANG Kai 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第6期1489-1495,共7页
Conventional analysis methods of cable structures do not consider sliding of cables inside the joint,which may lead to inaccuracy of the theoretical behavior of the structure.In order to develop an effective method fo... Conventional analysis methods of cable structures do not consider sliding of cables inside the joint,which may lead to inaccuracy of the theoretical behavior of the structure.In order to develop an effective method for cable sliding,a two-node cable element based on the analytical solution for an elastic catenary was studied.The cable sliding stiffness and the effect of friction were investigated.To validate the proposed numerical method,analyses of two examples given in the literature were conducted.The results demonstrated that the method given in this paper is accurate and effective,and can take into account cable sliding in cable structures.In addition,it was shown that the effect of cable sliding on the behavior of cable structures is significant.It was also shown that the friction at the support hampers the flow of the cable force,leading to unequal cable tensions on both sides of the support. 展开更多
关键词 CABLE elastic catenary FRICTION cable sliding nonlinear analysis
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DISCRETE-TIME Geo/G/1 RETRIAL QUEUES WITH GENERAL RETRIAL TIME AND BERNOULLI VACATION 被引量:3
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作者 Jinting WANG 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2012年第3期504-513,共10页
This paper considers a discrete-time Geo/G/1 retrial queue where the retrial time has a general distribution and the server is subject to Bernoulli vacation policy. It is assumed that the server, after each service co... This paper considers a discrete-time Geo/G/1 retrial queue where the retrial time has a general distribution and the server is subject to Bernoulli vacation policy. It is assumed that the server, after each service completion, begins a process of search in order to find the following customer to be served with a certain probability, or begins a single vacation process with complementary probability. This paper analyzes the Markov chain underlying the queueing system and obtain its ergodicity condition. The generating functions of the number of customers in the orbit and in the system are also obtained along with the marginal distributions of the orbit size when the server is idle, busy or on vacation. Finally, the author gives two stochastic decomposition laws, and as an application the author gives bounds for the proximity between the system size distributions of the model and the corresponding model without retrials. 展开更多
关键词 Discrete-time queue general retrial time retrial queue stochastic decomposition vaca-tion.
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