CO2局部腐蚀测试及评价方法

局部腐蚀测试及评价一直是困扰腐蚀界的一大难题.针对CO2局部腐蚀的特征,研发了一种测量CO2局部腐蚀的测试仪.它能准确测定局部腐蚀的有关几何参数,定量评定局部腐蚀的破坏程度,并根据CO2局部腐蚀的特征,建立一种评定CO2局部腐蚀的方法.     

基于局部主频率的子结构损伤识别研究与试验

针对大型复杂结构的整体监测常常面临测量信息不足等困难,提出只利用局部动态响应进行子结构损伤识别的局部主频率方法.子结构的局部主频率指:如果整体模态中含有以局部子结构位移为主的模态,即等价于在局部激励作用下,整体结构的振动主要体现为子结构的振动,并且主要以这阶局部模态振动为主,那么对应的该阶频率即定义为子结构的局部主频率.局部主频率主要反映子结构的局部特性,对子结构损伤的灵敏度高,所以只利用局部主频率就可以识别子结构.当子结构特征不明显时,提出通过附加质量使子结构具有局部主频率的有效方法.该文进行了大型空间桁架的局部动力测试试验,试验中通过附加质量使杆件子结构具有局部主频率,并能准确地识别出杆件损伤的位置和程度.     

配电网中压电缆振荡波局部放电检测技术研究

检测局部放电是提高电缆检修效率的重要方法,振荡波局部放电检测技术是一种新兴电缆检修技术,它能够精确找出电缆中的故障点。在振荡波局部放电检测系统中要解决局部放电检测中的干扰和放电缺陷类型的识别。本文将深入研究配电网中压电缆振荡波局部放电检测技术,进一步完善振荡波局部放电测试系统。     

浅谈采煤工作面局部冒顶原因及其防治方法

介绍了采煤工作面局部冒顶的原因,局部冒顶的规律,局部冒顶的地点,及预防措施。     

一类捕食-食饵模型分歧解的局部稳定性和全局分歧

本文利用局部分歧理论和局部稳定性理论,讨论了一类具有避难所的两物种间的捕食-食饵模型在非齐次Dirichlet边界条件下分歧解的性质,其功能反应函数为Holling Ⅱ型.利用局部分歧和局部稳定性理论给出了分歧解局部稳定的条件;同时利用度理论得到了局部分歧可以延拓到整体分歧的结论.     

变压器局部放电在线监测技术

变压器局部放电在线监测技术对变压器安全运行及提高电网的供电可靠性具有重要意义。通过对变压器局部放电在线监测技术进行分析,简要介绍了常见的变压器局部放电的几种监测方法、变压器内部局部放电定位以及监测过程中的抗干扰等方面简介了变压器局部放电在线监测技术。     

基于二阶矩显著性估算的局部不变特征提取

借鉴图像显著性区域的检测思想,提出一种基于局部二阶矩显著性估算的局部不变特征提取算法.利用二阶矩矩阵对尺度空间下局部图像的各向异性程度的估算作用,在图像尺度空间中对局部特征提取区域的信息显著性进行评估,并根据显著性进行局部不变特征的提取,提取出拥有较高显著性的局部不变特征,增加了匹配特征点对的数量和尺度跨度.真实图像实验证明,该算法在保持局部特征各种不变性的基础上有效地提高了特征提取和匹配算法的性能.     

局部放电测量仪校准方法研究

局部放电是一种危害性极大的放电现象,这种放电会极大的损坏高压电力设备的绝缘性能,导致高压设备存在严重的安全隐患。目前,高压设备的生产单位基本上采用局部放电测量仪进行局部放电的测量,但国家尚未出台局部放电测量仪的检定或校准规范。文章通过对局部放电测量仪工作原理的分析,并结合与局部放电测量仪在工作原理上有类似性常见测量仪器——示波器的校准方法,深入探讨和研究了局部放电测量仪的校准项目和校准方法的实施。     

煤矿局部通风机变频调速的应用前景

本文总结了煤矿局部通风机目前运行的现状，及变频系统目前的现状，通过局部通风机的运行特点，提出了局部通风机加设变频控制系统应该具有的功能，对今后变频局部通风的技术发展进行分析。     

顶板灾害性事故及其防治

【摘要】本文针对顶板的局部冒顶事故,支护突然失效局部冒顶事故,空顶冒落冲击局部冒顶事故,工作面上下端头局部冒顶,大型冒顶事故等产生的原因和有效的防治措施进行了论述。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.