主闸阀强度与刚度分析

根据主闸阀结构特点,分别用有限元法和椭圆柱板壳理论公式计算了阀体的强度与刚度,并进行了分析对比,同时对闸板的刚度进行了校核。     

Thermo‐oxidative stability of high‐temperature stability polyol ester jet engine oils — a comparison of test methods

Thermo‐oxidative stability in aerospace turbine oils is an important criterion. A new category (HTS) of turbine oil has been introduced, and the present work compares data on the oxidation stability of HTS oils obtained using the FTM 791, method 5308 test, at various temperatures, and PDSC experimental data, to standard class oils (STD). PDSC has become established in recent years as an effective means with which to establish the thermo‐oxidative stability of oils. The purpose of the present work was to find out whether PDSC could identify HTS oils correctly, and also to increase our understanding of some of the chemical processes behind the test results. Analogies in the degradation of the oligomer antioxidants have been confirmed by MALDITOF mass spectra.     

Friction modifiers in engine and gear oils

Reducing friction is an important target for any lubricant oil formulator. There are several ways, such as utilisation of multi‐grade oils with low viscosity at low temperature, or use of friction modifiers, to reduce friction in automotive engines and transmissions and thus save fuel. A good means to obtain an energy‐saving lubricant is by the addition of a friction‐reducing additive in a high‐range multigrade oil. This paper presents some considerations on the action mechanism of friction modifiers and the results obtained in engine and gear oils with two new nitrogen‐, sulphur‐, and boron‐containing additives.     

Engine friction lubricant sensitivities: A comparison of modern diesel and gasoline engines

Engine friction models have been developed that take account of the variations in lubricants with temperature, shear rate, and pressure. These models have been used to study the lubricant sensitivities of modern diesel and gasoline engines. Total engine friction losses for a Perkins Phaser four‐cylinder, 4.0 l, turbocharged, inter‐cooled diesel engine, operating at 1300 rpm, with an SAE 15W‐40 lubricant, were estimated at approximately 2 kW, with the piston assembly contributing 46%, the bearings 49%, and the valve train 5%. Total engine friction losses for a Mercedes Benz M111 2.0 l gasoline engine (used in CEC sludge and fuel economy engine tests) operating at 2500 rpm, and medium load, for an SAE 15W‐40 lubricant, were estimated at 1.5 kW, with the piston assembly contributing 42%, the bearings 39%, and the valve train 19%.     

广州旧城区居住条件改造的必然性与方法初探

由于土地资源的非重复利用性和现今城市建设的快速发展,城市不断向周边蔓延,新建筑在郊区拔地而起,而旧城区建筑却在不断老化。在广州这样一个历史文化久远、人口众多、旧城区面积较大的城市,很多居民生活在老旧建筑中。与旧城区相对完善、高质量的公共服务配套相比。居住条件却远远落后．因此对旧城区居住条件进行改善已是广州亟待解决的现实任务。     

场地岩土工程地质条件的改变对某建筑物基础设计的影响

文章就某场地由于周边道路标高降低后,引起整个场地的岩土工程地质条件发生较大的改变,对原先不能采用的人工挖孔桩方案是否还有采用的可能性进行探讨。     

西安微电子研究所悬挑钢桅杆整体提升技术

根据西安微电子研究所钢桅杆使用要求和设计特点,本文详细阐述了利用两台卷扬机走四滑轮组共同将18.6吨钢桅杆按对称方向从±0.000m提升至133.7m高空时的提升架设计、施工方法、原理及适用范围。该施工技术有效的解决了悬挑钢桅杆安装技术、工程安全和工程质量等问题,对同类钢结构工程起到一定的借鉴作用。     

新型老年保健康复社区概念规划设计研究——以泸州健康生态城为例

伴随着我国老龄化进程的逐渐加速,人口老龄化问题越来越严重,而与之相对应的养老问题成为社会关注的焦点。本文在分析我国养老模式和养老设施现状的基础上,结合作者参与的泸州健康生态城概念规划设计,对健康生态城这种"医、护、养"一体的新型老年保健康复社区的规划设计进行探索研究。     

Effect of the addition of 1-pentanol on engine performance and emission characteristics of diesel and biodiesel fuelled single cylinder diesel engine

ABSTRACT

Bioalcohols have recently become one of the promising alternate fuels. Lower alcohols exhibit some problems like phase separation, stability issues, storage problems, corrosion etc. Hence, the addition of higher alcohols is regarded least-problematic and the concept of using higher alcohols as fuel blends is relatively new. In this article, the effects of the addition of higher alcohol (1-pentanol) on engine performance and emission characteristics are discussed. Two reference fuels (diesel and biodiesel derived from waste cooking oil) and two test fuels (blends of 20% of 1-pentanol and 80% of either diesel or biodiesel) are tested in a single cylinder compression ignition diesel engine for six load conditions (0, 4, 8, 12, 16, and 20?kg) at a constant speed of 1200?rpm. The engine performance and emission characteristics are determined and discussed.     

特大跨度悬索桥概念设计

以琼州海峡跨海工程为背景,研究了跨度达10000 m特大跨径悬索桥的概念设计,研究表明,采用碳纤维加劲塑料可满足特大跨度桥梁的要求,辅助缆索在提高结构抗风性能方面作用很大,混合双悬臂体系在静力和动力方面均有更大优势,具有很广阔的发展前景。