大功率半导体激光器有源区温度影响因素分析

为了提高大功率半导体激光器模块散热性能,文中数值模拟研究了激光器模块的温度场,分析了焊料导热系数及其厚度、热沉导热系数和半导体制冷器冷面温度对芯片有源区温度及模块散热性能的影响规律.结果表明:焊料厚度在2~24μm范围内,无高阻层形成,模块散热性能稳定,而当焊料厚度大于24μm后,有源区温度迅速升高;随着热沉导热系数的增加,有源区温度呈指数形式下降,且当其导热系数小于1200 W/m·K时,温度降低更显著;半导体制冷器冷面温度与有源区温度呈比例系数为1的线性关系.     

船用铝合金与复合材料用防火材料导热系数研究

[目的]随着铝合金和复合材料结构件规模化上舰,原有防火材料已无法满足新需求。鉴于此,研制的新型防火材料需获得合适的导热系数。[方法]以标准耐火试验样件为研究对象,建立防火材料导热系数的算法。首先,使用无限大平板非稳态传热模型,进行空间-时域离散,实现耐火分隔传热过程的计算。其次,建立火场传热模型,对材料表面传热系数和发射率2个参数进行近似处理,并验证该近似处理对背火面温度的计算结果不产生明显影响。最后,通过分析铝合金、复合材料与钢材的高温力学差异,确定防火材料背火面温度的限值。通过导热系数的迭代,计算防火材料背火面温度,得到满足要求的导热系数。以陶瓷棉为例计算背火面温度,并与前人试验结果对比。[结果]背火面温度的计算结果与试验结果相符,验证了所提算法的可靠性。利用此算法,得到该防火材料用于铝合金结构时,导热系数应不大于0.032 W·m~(-1)·K~(-1);用于复合材料结构时,应不大于0.020 W·m~(-1)·K~(-1)。[结论]得到的导热系数可以为铝合金和复合材料结构用新型防火材料研制提供参考。     

填料改性绝缘漆导热性研究

本文研究了树脂基体、填料种类对绝缘漆导热系数的影响;通过对比试验,最终选用硅粉作为改性填料;研究了硅粉表面处理方法和含量对绝缘漆导热性及粘度的影响。使用经表面处理硅粉,添加量在30%（质量比）时,导热率从0.18W/（m·K）增加至0.35W/（m·K）,而粘度为65s,仍能满足使用工艺要求。     

舱壁保温层对深潜器舱内温度的影响

通过数值模拟的方法,对深潜器下潜和巡航过程中的传热进行分析,研究下潜速度、保温层厚度、保温层导热系数对舱内温度和内壁面温度的影响。下潜速度的增加,从时间上考虑,对舱内温度影响较小。随着导热系数的增加,保温层厚度变化对舱内环境温度影响程度减小。导热系数一定时,保温层厚度增加,舱内环境温度会线性上升,而环境温度与舱内壁面温差则线性减小。随着保温层厚度的上升,导热系数的变化对舱内环境温度影响程度变大。保温层厚度一定时,导热系数增加,舱内环境温度会加速下降,环境温度与舱内壁面温差加速上升。因此,保温层导热系数应尽量选取靠近0.1 W/(m·K),而厚度以3cm为宜。     

基于COMSOL有限元模拟大体积混凝土温度裂缝研究

为控制基础大体积混凝土施工因水化热过大产生的温度裂缝,在对筏板基础大体积混凝土施工温度监测的基础上,采用有限元软件comsol对筏板基础进行温度场仿真模拟分析,研究筏板基础温度变化曲线及温度场随时间变化规律。模拟结果表明:采用有限元软件comsol对筏板基础进行温度模拟,模拟结果与实测数据基本吻合,说明可以用数值模拟方法,预测大体积混凝土在不同浇注温度及导热系数影响因素下温度变化趋势。     

高温地区大体积混凝土固化过程中温度场的模拟分析及试验验证

大体积混凝土温度场的数值模拟对制定施工策略至关重要,而目前针对高温地区大体积混凝土温度场的模拟方法研究较少。文章以高温地区施工的大体积混凝土方块为研究对象,采用数值模拟与原型监测相结合的方法,开展了高温地区大体积混凝土固化过程中的温度场模拟方法研究,提出了相应的数值模拟方法及关键参数的选取建议。研究表明:高温地区大体积混凝土温度场模拟时,水化热应以不同时间点水化热量的差值作为水化热生成率进行施加;降低混凝土表面的放热系数,模拟得到的混凝土最高水化热温度略有增加,但幅度不大;水泥最终水化热量取值增加,可明显提高模拟结果中混凝土的温度值,进行高温地区大体积混凝土温度场模拟时,应扩大最终水化热量取值,方可使温度模拟结果与原型观测结果统一。     

高导热绝缘衬垫材料的研究

本文研制了可用于层压母线的高导热绝缘衬垫材料。分别选用聚酯(PET)、聚酰亚胺(PI)、间位芳香族聚酰胺纤维(NOMEX纸)作为基材,对比了三种基材的导热性,然后双面涂覆自制高导热胶粘剂,制成导热绝缘衬垫材料。TGA结果表明自制高导热胶粘剂的热稳定性较普通胶粘剂有一定提高。所制得的PI导热绝缘衬垫材料最高导热系数可达0.316 W/(m·k),并表现出了较好的综合性能。     

基于流固耦合的某船用低速柴油机活塞温度场分析

针对某研发新型船用柴油机,建立其活塞固体域和流体域模型,运用有限元软件ABAQUS和流体动力学软件START-CCM+进行联合仿真,得到其活塞耦合面对流换热系数和温度场分布。活塞最高温度538K左右,活塞第一环区及环区附近区域大部分温度439K在左右,活塞环区及活塞内部冷却腔大部分温度处于340K~439K范围以内,最后与现有对标机型进行对比,得到仿真计算所得活塞温度分布与对标机型温度场实测值基本一致,活塞温度场仿真计算结果基本符合实际。     

动态法计算大体积混凝土中心温度

采用动态方法,不断调整反映水化速率的系数m,计算混凝土不同时期绝热温升.基于发热和导热方程,给予一定的简化,建立混凝土结构温度散热模型.选择合适的边界条件计算大体积混凝土中心实际最高温度.     

独立罐型LNG船温度场分析及应用

以某安装B型独立罐的液化天然气(Liquefied Natural Gas, LNG)船为例,按照《国际散装运输液化气体船舶构造和设备规则》(简称《IGC规则》)、美国海岸警卫队(USCG)规则(简称USCG规则)和船级社规范的相关要求,研究该船的温度场计算方法和流程、材料导热系数和对流系数的取值及纵向构件、横向强框和横舱壁的温度场分布。分析该船在《IGC规则》和USCG规则环境工况下的温度场分布和钢等级选取,研究该船LNG日蒸发率的计算,得出对独立罐型LNG船的温度场分析和应用有意义的结果。     

33rd International Conference on Ocean,Offshore and Arctic Engineering （OMAE2014）

正San Francisco,California,June 8-13,2014.OMAE 2014 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to:·meet and present advances in technology and its scientific support;·to exchange ideas and experiences whilst promoting technological progress and its application in industry·to promote international cooperation in ocean,offshore and arctic engineering.In line with the tradition of excellence of previous OMAE conferences,more than 900 technical papers are planned for presentation.Outreach for Engineers Specialty Forum This Specialty Forum is designed for students and professionals who may not be familiar with the Ocean and Offshore industry,as well as those who have just recently specialized in this field.     

The 11th International Conference on Hydrodynamics (ICHD 2014)

正19–24 October 2014 SingaporeCONFERENCE THEMES The overall aim of the ICHD Conference is to provide a forum for participants from around the world to review,discuss and present the latest developments in the broad discipline of hydrodynamics and fluid mechanics.The first International Conference on Hydrodynamics(ICHD)was initiated in 1994 in Wuxi,China.Since then,9 more ICHD conferences were held subsequently in Hong Kong,Seoul,Yokohama,Tainan,Perth,Ischia,Nantes,Shanghai and St Petersburg.Evidently the ICHD conference has become an important event among academics,researchers,engineers and operators,working in the fields closely related to the science and technology of hydrodynamics.The 11th ICHD will be held in Singapore in 2014.     

第十二届深水操作会议和展览会(英文)

正November 4-6,2014Moody Gardens HotelConvention Center/Galveston,TX The Deepwater Operations Conference and Exhibition is celebrating its 12th anniversary this year.This growing event will continue the tradition of excellence in addressing operational challenges involved in developing deepwater resources.We will return to the Moody Gardens Hotel and Convention Center on November 5-7,2014 in Galveston,Texas.     

舰艇反鱼雷技术

对目前舰艇反鱼雷技术中的非杀伤、软杀伤和硬杀伤等比较先进的手段进行了阐述,并在此基础上分析研究了舰艇反鱼雷技术的发展趋势。     

Community-Based Management for Sustainable Fisheries Resources in Phang-nga Bay,Thailand

Fishing communities, the Government of Thailand Department of Fisheries, local nongovermnental organizations, universities, the Food and Agriculture Organization of the United Nations (FAO), and FAO's Bay of Bengal Program have undertaken a partnership in management of Phang-nga Bay's coastal resources. It is the first project of its kind in Thailand, and although still in the early stages, offers insights that may contribute to our knowledge of how we can improve our management of coastal resources, including the importance of (1) building relationships within the governance process; (2) combining education, enforcement, and economic incentives to achieve compliance; (3) implementing solutions early; and (4) government support of community-based decisions. These insights reinforce trends emerging in other coastal management projects in the Asian region.     

Catalyzing Coastal Management in Kenya and Zanzibar: Building Capacity and Commitment

Site-based projects were initiated in Chawka Bay-Paje, Zanzibar, and Nyali-Bamburi-Shanzu, Kenya, to demonstrate the benefits of an integrated coastal management (ICM) approach for addressing coastal issues such as tourism development and enhancement of resource-dependent village economies in eastern Africa. A two-year, multidonor project used three primary strategies to make rapid, but sustainable, progress toward ICM. These included using interagency government teams for ICM planning, adopting an internationally recognized framework for ICM as a project ''road map,'' and explicitly incorporating capacity-building strategies into all aspects of the project. Within two years, integrated ICM action strategies, prepared through participatory processes, were being implemented at both sites, and both teams were working to expand the scale and scope of ICM in their nation. More importantly, the project helped create committed, capable, interagency groups that continue to work together to address urgent ICM issues.     

Journal of Marine Science and Application 2014 Sum. Contents

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Errata

正In the paper"Influence of Fouling Assemblage on the Corrosion Behaviour of Mild Steel in the Coastal Waters of The Gulf of Mannar,India"in Vol.12,No.4,Page:509,References were lost,and the two authors’biographies were identical.The correct text is shown below.We apologize to the authors and our readers for any inconvenience caused by the errors.     

单相PWM整流器的建模与仿真分析

文章详细分析了单相VSR型PWM整流器的整流原理,建立了电流内环,电压外环的单相VSR型PWM整流控制器的数学模型和逻辑框图。在MATLAB／Simulink软件环境中进行了仿真,分析了模型的可行性。     

无人反潜系统自主指挥控制研究

无人反潜系统的指挥控制问题是关系其具备实际作战能力的主要问题之一。论文在分析无人反潜系统指控原理和其自主指控水平分级的基础上,采用可变自主控制结构,研究了无人反潜系统分级可变自主指控实现的方法。该方法可赋予无人反潜系统可变的指挥控制自主性,使其在工作环境中能够实时评估自身的自主能力,并主动引入人工干预。这种具备人机智能融合特性的自主指挥控制方法更适应无人反潜系统在复杂战场环境中实战化的需求。