稳态对流扩散方程解的概率表示

给出了有界区域Ｄ 上的稳态对流扩散方程Δｕ／２ ＋ ｂ ·ｕ ＝ ０ 的解ｕ 可表成如下形式ｕ（ｘ）＝ Ｅｘ φ（Ｂτ）ｅｘｐ （∫τ０ｂ（Ｂｓ）ｄＢｓ－ １２∫τ０｜ｂ（Ｂｓ）｜２ｄｓ） 　ｘ∈Ｄ的两个等价条件（这里Ｂｔ 是Ｂｒｏｗ ｎ 运动,τ是Ｄ的首出时,φ是Ｄ上可测函数）。证明了稳态对流扩散方程随机Ｄｉｒｉｃｈｌｅｔ 问题解的存在唯一性。     

差商插值法在热电偶热电势计算中的应用

一支标准热电偶在锌凝固点ｔ１、锑凝固点ｔ２和铜凝固点ｔ３分度后，确定了相应的热电势Ｅ（ｔ１）、Ｅ（ｔ２）和Ｅ（ｔ３），从而可求出该三点上的热电势Ｅ（ｔｉ）与参考函数Ｅｒ（ｔｉ）的差值：ΔＥ（ｔ１）＝Ｅ（ｔ１）－Ｅｒ（ｔ１）ΔＥ（ｔ２）＝Ｅ（ｔ２）－Ｅ...     

捕食种群具有常数收获率并具有Ⅲ类功能性反应的食饵-捕食系统

讨论了捕食种群具有常数收获率,并具有Ⅲ类功能性反应的食饵－捕食系统ｘ＝ｒｘ（１＝－ｘ／ｋ）－ωｘ＾２ｙ／ｘ＾２＋ａ;ｙ＝ｙ（－ｄ＋ｃｗｘ＾２／ｘ＾２＋ａ）＋μ给出了此系统在第一象限内的有所可能的拓扑结构,并证明了此系统在第一象限内至少可以存在两个象限环。     

R~n中半线性椭圆方程Δu k(｜x｜)u~p=0注记

讨论了 Ｒｎ（ｎ ＞ ２） 中半线性椭圆方程 Δｕ ＋ ｋ（｜ｘ｜）ｕｐ ＝ ０ 的正径向解的存在性与渐近性，２ 个定理分别改进推广了前人相应的结果     

n阶非线性时变系统的渐近稳定性

用系统分析的方法给出了保证ｎ阶非线性时变系统ｄｘ／ｄｔ＝Ａ（ｔ）ｘ＋ｆ（ｔ,ｘ）之零解渐近稳定的充分条件。     

一阶与二阶泛函微分方程的边值问题

本文考虑以下泛函微分方程的边值问题：“ｘ＇（ｔ）＝ｆ（ｔ，ｘｔ）（０≤ｔ≤ｂ），ｘ０＝ｘｂ″及“ｘ“（ｔ）＝ｆ（ｔ，ｘｔ，ｘ＇（ｔ）（０≤ｔ≤ｂ＿，ｘ０－ψ，ｘ（ｂ）＝Ｂ”。利用基于度理论的不动定理，给上述边值问题有解的某些充分条件。     

具有超高压电电压常数的镧掺杂0.55Pb（Sc1／2Ta1／2）O3—0.45PbTiO …

研究了不同镧掺杂量与Ｐｂ（１－ｘ）Ｌａｘ（Ｓｃ１／２Ｔａ１／２）０．５５Ｔｉ０．４５Ｏ３（ｘ＝０，ｘ＝０．００５，ｘ＝０．０１，ｘ＝０．０ｘ，ｘ＝０．０３）陶瓷材料居里温度，压电常数有压电电压常数之间的关系以及高温热处理对材料性能的影响。研究表明材料的居里温度随镧添加量的提高按２６℃／１ａｔｍ％的幅度下降，只是在ｘ＝０．００５处出现异常现象，即该组分的材料的居里温度与ｘ＝０处相比稍有提高；材料的压     

A3钢在环烷酸中腐蚀的物理化学行为

用失重法测定了不同温度下Ａ３钢在环烷酸中的腐蚀速率。将试验结果与热力学和动力学方程进行拟合，得到温度与腐以应速度常数方程为：ｌｎｋ＝９．４６－４．３６５／ｔ，环烷酸与Ａ３钢的反应表观活化能为：Ｅａ＝３４６ｋＪ／ｍｏｌ，摩尔反应为：Ｑ＝ΔＨ＝２５．２ｋＪ／ｍｏｌ。用簇集理论分析了环灶酸分子的缔合状态与Ａ３钢的腐蚀的关系。     

锂快离子导体Li_(1 2x y)Al_xYb_yTi_(2-x-y)Si_xP_(3-x)O_(12)系统的研究

以ＬｉＴｉ２（ＰＯ４）３为基以天然高岭石为起始原料,经高温固相反应（９５０～１１５０℃）制得了 一系列锂快离子导体材料Ｌｉ１＋２ｘ＋ｙＡｌｘＹｂｙＴｉ２－ｘ－ｙＳｉｘＰ３－ｘＯ１２（以下简称Ａｌ－Ｙｂ－Ｌｉｓｉｃｏｎ）．系统 的合成温度随ｘ和ｙ值的增大而降低．应用交流阻抗技术测定的电导率数据结果表明ｙ＝０．３, ｘ＝０．１的合成物的电导率最好,４００℃时电导率达２．４５×１０－２Ｓ／ｃｍ, ２００～４００℃内的电导激 活能为３８．３ｋＪ／ｍｏｌ．ＸＲＤ分析结果表明在ｙ＝０．３,ｘ≤０４及ｙ＝０．５,ｘ≤０．３的组成范围内 均能得到空间群为Ｒ３ｃ的合成物．     

高阶Duffing方程周期解存在唯一性的新证明

对高阶Ｄｕｆｉｎｇ方程ｘ（２ｎ＋１）＋ｇ（ｔ，ｘ）＝０周期解的存在唯一性进行了构造性证明，同时提供了一种可数值求解的方法．     

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.