曲线坐标下平面二维污染物扩散输移的代数应力湍流模型

对浅水流动的控制方程和深度平均的污染物扩散输移的控制方程进行坐标变换，湍流的模拟采用各向异性代数应力湍流模式，建立了曲线坐标下平面二维水流计算和污染物扩散输移的代数应力湍流模型。采用具有浓度实测值的实验室连续弯道进行模型验证，对本模型计算的浓度分布与k-ε模型进行比较，结果显示了本模型在处理各向异性明显优于k-ε模型。     

山区流域泥沙输移比计算公式

本文在分析影响泥沙输移比主要因素的基础上，分别对坡面上单位面积输沙率ｑｓ和坡面上单位面积产沙率Ｓｙ进行了量纲分析，了ｑｓ和Ｓｙ的数学表达式，从而获得了山区流域尼沙输移比的计算式。     

火电厂污染物扩散模型研究

本文讨论了影响气体污染物扩散运动的因素。气体污染物的扩散运动受污染物本身的性质、地理条件、大气因素和风速风向影响,其中以风速风向影响为主。对比了4种扩散模型的优缺点后,选择了实时性强,计算速度快,适合应用到电力系统中的高斯扩散模型。     

顶部开孔组合方式对城市公路隧道自然通风的影响

利用SES模拟软件,采用数值计算方法研究了城市公路隧道采用顶部开孔的自然通风方式时隧道内的气流运动和污染物扩散的问题。根据实际隧道几何尺寸,截取1000米隧道作为算例,研究了自然通风孔布置情况对隧道内空气流动及污染物扩散的影响。结果表明:在开孔数量和总开孔面积不变的情况下,与多个通风孔集中布置时相比单个通风孔均匀布置时隧道内通风换气效果最差,隧道沿程排放污染物能力最弱;而多个通风孔集中布置时五个孔一组的通风换气效果最好,隧道沿程排放污染物能力最强。     

一种低扩散率水扩散管的理论分析及研制

介绍低扩散率水扩散管的扩散原理及一种低扩散率水扩散管的设计。详细阐述了扩散式湿度发生器的基本结构，水扩散管水分蒸发率与扩散率的理论计算方法。通过扩散管基体材料选择和结构研究，设计了多种扩散率的水扩散管。     

街道峡谷内细微颗粒物扩散特性的DPM数值模拟

应用离散相模型(DPM)对城市中典型的街道峡谷内细微颗粒污染物浓度场进行了模拟,计算湍流模型选择标准k-ε双方程模型.计算结果表明,城市风场作用于街谷内导致涡旋流动,进而影响颗粒物的扩散分布.背风侧壁面颗粒物的浓度场呈现明显的"爬墙效应".不同几何结构影响颗粒物的浓度场,递增型街谷模型更有利于颗粒污染物的扩散.     

试论生态水利工程设计的基本原则

按照河流地貌学原理进行河流纵、横断面设计时，必须充分考虑河流泥沙输移、淤积及河流侵蚀、冲刷等河流特征，动态地研究河势变化规律，保证河流修复工程的耐久性。     

厨房污染物扩散机理可视化模拟软件开发

基于VC++6.0平台运用OpenGL编程技术开发厨房污染物扩散模拟的可视化软件,分析厨房内污染物传播的规律,给出无机械通风条件下相应的扩散模型.对这种典型扩散模型使用OpenGL图形图像编程技术,在VC++平台上实现点源扩散的可视化模拟.通过模拟得到二维和三维的浓度扩散图,发现厨房内污染物浓度扩散符合高斯模式.证明该软件在进行典型模型的模拟及可视化方面是可行的,为进行有通风条件等复杂情况的模拟软件开发奠定了基础.     

液膜电渗析的应用

介绍了液膜电渗析的原理及应用，包括浓缩、提取化合物、合成高纯物质及脱盐，由于它将化学反应、扩散过程和电迂移三者结合起来，因而有广泛的应用前景。     

基于扩散-对流模型的海底混凝土隧道耐久寿命预测

考虑海底隧道承受侵蚀性高压力海水的服役环境特点以及高性能混凝土的非饱和特性,建立了海底混凝土隧道氯离子扩散-对流传输模型和耐久寿命预测模型。以舟山沈家门海底隧道为工程背景,通过室内实验确定计算参数,采用TOUGH2软件数值模拟了环境中氯离子侵入隧道的传输过程,得到了氯离子经时传输规律,以及水头、混凝土初始饱和度、环境氯离子质量分数的作用规律,比较了扩散、饱和扩散-对流、非饱和扩散-对流预测模型的计算差异。结果表明：海底隧道腋角位置的氯离子质量分数累积最高;水头和环境氯离子质量分数与氯离子质量分数增长呈正相关,混凝土初始饱和度与氯离子质量分数增长呈负相关;按照扩散模型预测得到的隧道耐久寿命最长,按照非饱和扩散-对流模型预测得到的耐久寿命最短。     

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.