基于评标模式的公路工程造价研究

招标投标是我国工程项目进行施工承包重要的的方式。而评标的是公路工程的建设项目的招标投的标的关键环节。为了保证评标环节的公平、公正、科学、合理,保护招投标双的方的利益的,提高工程的建设的质量,研究科学、合理、有效的评标理论具有十分重的要的意义。     

阐析高速公路路基的路面施工

我国的交通运输行业的发展借助的是我国的经济的高速的发展。我国交通运输业的发展也直接带动了我国的高速公路的发展。在我国的高速公路的建设过程中,关于路基路面的施工还是存在着很多的问题的。本文针对高速公路路基路面施工的问题,来进行相关的讨论和分析,讨论高速公路路基施工中的施工工艺的应用,为高速公路的建设贡献自己的力量。     

对低压成套开关设备绝缘配合问题的探讨

电气工业的都配备有低压的成套的开关设备,我国的百分之八十左右的电能供给都是通过低压的成套的开关设备予以供出,低压的成套的开关设备的发展与工业材料制作,工艺产品和加工设备,低压的电器,人们的生活水平和基础的设施建设息息相关,所以它从一个侧面凸显了一个国家的综合国力,而其中的绝缘配合是一个关联到电气产品的安全性的至关重要的问题,应该要有非常的重视     

220kV变电站主接线运行经济性选择的探讨

变电站的主接线的设计是依据变电站的最高电压以及变电站的性质决定的。通过地区的电网的运行的实际情况出发,对220kv的变电站的主接线的运行进行了详细分析,并对变电站的主接线的设置进行了比较与分析。     

如何进行施工项目的管理和成本的控制工作

随着我国经济的不断发展,我国的基础设施的施工工程越来越多,在施工的过程中,施工项目的管理工作越来越重要。作为现代的企业来讲,施工的项目管理是非常的重要的,这主要是因为施工的企业只有做好施工项目的管理工作才能不断的完善现在的企业管理制度,使企业的管理工作更加的完善。企业只有做好施工项目的管理工作才可以提高企业的经济效益,进行项目施工的时候一定要进行必要的成本控制,这样才能够使企业的社会信誉得到提高,并且可以使企业的发展空间得到更大的提升。     

石化行业的污水处理探析

伴随着世界范围内的资源再利用的步伐,我国的石化行业的从业单位不断的发展壮大,与此同时人们的环保概念不断的在进行加强。石化行业的污水的处理方式已经越来越受到社会的关注。如何处理石化行业的污水已经是一种议题。随着我国的工业化程度的深入,我国石化行业的工业废水已经变化的多种多样,很多的化学污染物掺杂其中,这样就会对我们的化工行业的污水处理带来很多的困难。针对这种现状,我们要做的就是要不断的提升化工行业污水处理的质量和效率。本文就是针对这种问题来进行详细的论述。     

建筑施工中室外照明的接地故障保护和短路保护方法之研究

随着我们国家的经济的迅猛发展,人们的生活水平也是越来越高。人们对周围的环境的要求也是越来越严格。照明系统作为城市道路的一个明显的环节。由于室外的照明的场所的不同,所以室外照明供电系统的供电的方式也是不一样的。本文是通过对室外照明线路的选择以及供电系统的选择进行分析,为以后的室外照明的相关工程提供有利的依据。     

浅析当前公共财政政策存在的问题及对策

随着我国改革开放的不断的深入进行以及社会主义市场经济的建立和不断的完善,极大的改变了我国公共财政所面对的环境。当前我国的财政体制改革起的了很大的成功,极大的促进了我国经济的发展,但是在财政体制改革的过程当中也暴露出我国公共财政存在的一些问题。文章对当前我国公共财政存在的问题进行了深入的分析,并有针对性的提出了改进的建议,促进我国公共财政的发展。     

关于人的全面发展的探究

实现和促进人的全面发展不仅是马克思主义的一个重要理论,而且也是建设社会主义新社会的本质要求。人的全面发展的内涵应包括人的本质的全面发展、人的需要的全面发展、人的素质的全面发展和人的能力的全面发展。人的全面发展还是有其具体性、阶段性、历史性的,人的全面发展受生产力和生产关系的制约。     

热电厂电气的安全使用

热电厂电气的安全使用包含的有几个方面的内容。主要分为热电厂电气主设备的安全选择、热电厂电气运行的安全管理的措施、在工作中防治电气失误操作的措施和对策以及在热电厂安全生产中的个性化和人性化的管理等等。热电厂电气的安全使用对电厂的生产以及人们的正常的生产和生活都有重要的意义,因此,本文通过对热电厂电气的安全使用的几个方面的论述来进一步说明在热电厂的工作流程中电气的安全使用所占有的重要地位。特别是在经济迅速发展的中国,在电力建设的规模不断扩大的中国,作为热电厂的一名工作人员,更是要尽自己的力量来使电厂的各方面得到快速协调的发展。通过对热电厂电气的安全使用的论述,使得热电厂向着速度更快、电容量更大、参数更高以及电网更大的方向发展。     

抗氧添加剂在不同颗粒粒径聚丙烯粉料中添加效能差异的分析

将聚丙烯抗氧添加剂分别添加到不同粒径大小的聚丙烯粉料中后,再将粉料进行挤压造粒,比较造粒后的粒料抗氧化性能(即热氧化诱导期)的差异,说明添加剂在不同颗粒粒径聚丙烯粉料中添加效能产生差异的原因。     

Austenite grain size in the continuous casting process: Metallographic methods and evaluation

Austenite grain size is an important parameter for the ductility of steel at elevated temperatures. Therefore, indirect measurements of austenite grain size on slab samples and a specimen from laboratory experiments were carried out. To reveal the prior austenite grain boundaries three etchants (picric acid, ammonium persulfate and nital 3%) were used. One of the main objectives of the present work was to investigate how far the grain size distribution in the specimen from the laboratory experiment corresponds with the grain size distribution on – and beneath – the surface of a continuously cast slab. The measured grain size distribution of a slab and a laboratory experiment – both with an equivalent carbon content of 0.21 wt.% – show a good agreement. A clear maximum grain size can be found for a carbon equivalent of between 0.15 and 0.17 wt.%. The results of the presented metallographic examinations serve as an important basis for the development of an austenite grain growth model.     

低碳钢微型试样塑变机制的研究

本文对低碳钢微型试样在扫描电镜装置上所作的动态拉伸观测结果进行的分析表明:物理屈服现象的产生具有尺寸效应,即当试样厚度减至与晶粒尺寸相当时,物理屈服不再出现。表现在起始塑变机制上,则可能的机制是:先发生晶粒倾转,然后才出现晶粒内滑移带。     

The influence of flow-induced anisotropy on the impact behaviour of injection-moulded short-fibre composites

The objective of this paper was to develop further the concept of subcomponent testing, as suggested by Stephenson, Turner and Whale, to cover an assessment of the impact properties of polymer and composite components. To this end disks of polypropylene and glass-fibre-reinforced polypropylene were cut from plaques moulded with a range of gateing systems and subjected to mechanical testing at a range of speeds. Slow indentation testing could not distinguish between disks with or without a central weld-line, whereas instrumented falling-weight impact tests produced different failure modes and significant changes in the amount of energy absorbed between specimen subsets. The concept of sub-component testing is supported by these results while the need for the sub-components to be tested over a realistic range of conditions is highlighted.     

水泥混凝土道面早期抗裂性能试验研究

针对传统的普通道面混凝土施工后经常出现裂缝的现象,分析了裂缝产生的原因,提出在普通道面混凝土中掺加粉煤灰、聚丙烯纤维的新型道面混凝土,采用平板法进行了抗裂性能对比试验。结果表明：在普通道面混凝土中单掺粉煤灰或聚丙烯纤维,都能提高混凝土的抗裂性,而粉煤灰和聚丙烯纤维双掺的新型道面混凝土更能有效防止裂缝的发生,显著延长道面使用寿命。     

Effects of specimen and grain sizes on compression strength of annealed wrought copper alloy at room temperature

Variations in compression yield strength of annealed wrought CuAl7 copper alloy with specimen diameter (t) in 1–10 mm range and grain size (D) in 24–172 μm range were investigated. Both grain size effect and feature size effect could be observed. The compression yield strength increased with a reduction in grain size or specimen diameter, and varied with the t/D ratio in no particular manner. However, when t was held constant, the compression yield strength increased as the ratio increased. When D was held constant, the strength decreased as the ratio increased. The Hall–Petch relationship between the compression yield strength and the grain size was found to depend on the specimen diameter. The effect of feature size was greater than that of grain size. A new model of the relationship between the compression yield strength and the grain size, specimen diameter, and size factor has been built. The predicted results of the model agreed well with the experimental results. The fit of the model was better than that of a model based on the relationship between the compression yield strength and the grain size and specimen diameter only.     

INITIATION AND GROWTH OF SMALL CRACKS IN DIRECTIONALLY SOLIDIFIED MAR-M247 UNDER CREEP-FATIGUE PART II: EFFECT OF ANGLE NETWEEN STRESS AXIS AND SOLIDIFICATION DIRECTION

This paper deals with the effect of anisotropy on fracture processes of a directionally solidified superalloy, Mar-M247, under a push–pull creep-fatigue condition at high-temperature. Three kinds of specimen were cut from a cast plate such that their axes possess angles of 0°, 45° and 90° with respect to the 〈001〉 orientation that is aligned parallel to the solidification direction (also to the grain boundaries and primary dendrite axis); these specimens being denoted the 0° specimen, the 45° specimen, and the 90° specimen, respectively. The tests were conducted at 1273  K (1000 °C) in air under equal magnitudes of the range of a Δ J -related parameter, Δ W _c , which represents the driving force for crack growth in creep-fatigue. Although the grain boundaries are macroscopically parallel to the solidification direction, they are wavy or serrated microscopically. Small cracks nucleate along parts of the grain boundaries perpendicular to the stress axis in all specimens. The 90° specimen has the shortest crack initiation life and the 0° specimen has the longest. In the 90° and 45° specimens, intergranular cracks continue to nucleate and a main crack is formed along the grain boundary due to the frequent coalescence of small cracks. In the 0° specimen, cracks grow into the grain, and transgranular cracks coalesce along the primary dendrite or grain boundary. The 0° specimen exhibits the slowest crack growth rate and the 90° specimen the fastest. These differences in the initiation and growth behaviour of small cracks cause the longest failure life in the 0° specimen and the shortest in the 90° specimen.     

Flexural behaviour of hybrid laminated composites

The present paper studies the flexural behaviour of hand manufactured hybrid laminated composites with a hemp natural fibre/polypropylene core and two glass fibres/polypropylene surface layers at each side of the specimen. When compared with full glass fibres reinforced polypropylene laminates, the hybrid composites have economical, ecological and recycling advantages and also specific fatigue strength benefits. Static and fatigue tests were performed in three point bending for both laminates to evaluate flexural strength properties and fatigue behaviour. Fatigue damage was measured in terms of the stiffness loss. Failure sites and mechanisms were evaluated through microscopy studies and a 3D numerical analysis using finite element method.     

The influence of grain size on the ductility of micro-scale stainless steel stent struts

Vascular stents are used to restore blood flow in stenotic arteries, and at present the implantation of a stent is the preferred revascularisation method for treating coronary artery disease, as the introduction of drug eluting stents (DESs) has lead to a significant improvement in the clinical outcome of coronary stenting. However the mechanical limits of stents are being tested when they are deployed in severe cases. In this study we aimed to show (by a combination of experimental tests and crystal plasticity finite element models) that the ductility of stainless steel stent struts can be increased by optimising the grain structure within micro-scale stainless steel stent struts. The results of the study show that within the specimen size range 55 to 190 μ m ductility was not dependent on the size of the stent strut when the grain size maximised. For values of the ratio of cross sectional area to characteristic grain length less than 1000, ductility was at a minimum irrespective of specimen size. However, when the ratio of cross sectional area to characteristic grain length becomes greater than 1000 an improvement in ductility occurs, reaching a plateau when the ratio approaches a value characteristic of bulk material properties. In conclusion the ductility of micro-scale stainless steel stent struts is sensitive to microstructure and can be improved by reducing the grain size.     

热处理对1Cr18Ni9不锈钢晶界特征分布的影响

采用电子背散射衍射（EBSD）技术研究了不同热处理工艺下1Cr18Ni9不锈钢的晶界特征分布。结果表明,原始态试样低∑-CSL晶界含量在85％左右,主要分布在∑3,∑9,∑27和∑29四个晶界处;热处理后晶界特征分布变化明显,在水淬试样中低∑-CSL晶界主要集中在∑3和∑9处,∑3晶界占所有低∑-CSL晶界的90％以上;在深冷试样中∑3晶界的比例更大,占全部低∑-CSL晶界的95％以上;水淬和深冷试样特殊晶界的含量基本一致,但在材料中的分布明显不同：水淬试样中低∑-CSL晶界主要分布在大角度晶界处,但CSL晶界没有形成网络;在深冷试样中低∑-CSL晶界主要分布在大角度晶界构成的晶界网络上,且形成了网络化的特殊晶界,有效阻断了一般大角度晶界间的连通性。