气流粉碎法制备超细硅酸钙粒子的研究

采用超音速气流粉碎法进行硅酸钙的超细粉碎，借助激光粒度仪和TEM进行超细粒子粒径和形貌表征。得到了平均粒径1.1μm、粒径分布0．4－3μm、粒子大小形状基本一致的超细硅酸钙样品。研究表明，气流粉碎后的超细粒子易于形成软团聚，但在应用时容易分散。     

煤的超细气流粉碎和分级对组成和结构的影响

利用超细气流粉碎及旋风分离对3种不同煤阶典型煤样进行超细粉碎研究,对粉碎前后各粒径煤样进行工业分析和元素分析,探讨超细气流粉碎及分级对各粒径煤样组成和结构的影响。结果表明,气流粉碎及两级旋风分离后煤样体积平均粒径分别达到约5.0μm和2.5μm,算术平均粒径可达亚微米级;煤岩组分及矿物质得到一定程度的解离,各粒径煤样的组成和结构发生明显变化,有利于煤岩显微组分的分离富集及无机矿物质的脱除。     

B4C超细粉末的制备及烧结

采用气流粉碎对B4C粗粉（比表面积0.52m^2/g，中位粒径20.4μm)进行了一系列粉碎实验，研究了气流粉碎次数，成形压力和烧结温度对烧结密度的影响。结果表明，当粉碎次数达到3次后，可获得＜1μm的B4C超细粉末。经过4次气流粉碎的B4C超细粉末的比表面积为2.53m^2/g，中位粒径为0.56μm；该粉末分别于2200和2250℃无压烧结1h，其烧结密度分别达到理论密度的78．6％ 82．5％，平均晶粒尺寸分别为28和50μm，抗压强度分别为390和555MPa。     

PVC树脂低温超细气流粉碎研究

对PVC树脂进行低温冷脆处理,可以有效地实现PVC树脂的超细粉碎。利用PVC树脂低温超细气流粉碎系统通过液氮致冷降低粉碎温度。使PVC超细粉碎效率得到提高。并在每千克PVC粉体液氮耗量为131mL～167mL的范围内。每小时获得8．23kg～11．65kg、平均粒径为6．45μm～9．02μm的超细PVC粉体。     

浙江丰利超细辊压磨成为非金属矿深加工设备首选

超细辊压磨则是非金属矿最重要的深加工技术之一。因为多数非金属矿物料在普通机械冲击力作用下很难粉碎到粒径小于1 000目(13μm)。为此,各国科技工作者在这方面开展了大量的研究,希望寻找出能在常温下非金属矿物料超细化的较理想的方法。前苏联、美国、英国和日本在这方面研究卓有成效,德国在这方面的研究也很系统全面,开发了一种自转加公转的粉碎方式,可在常温下将非金属矿粉碎粒径小于1 000目(13μm),而且产量高。我国超细辊压磨的生产尚在     

超细高氯酸铵粉体制备研究

文章研究了用扁平式气流粉碎机对高氯酸铵（AP）进行超细化粉碎，探索出了最佳粉碎工艺条件，制备了平均粒度为2μm的超细高氯酸铵（AP）粉体；分析了高氯酸铵（AP）超细粉碎过程中静电产生的原因，提出了消除静电积累方法，保证了粉碎过程安全。     

B4C超细粉末的制备及烧结

采用气流粉碎对Ｂ_４Ｃ粗粉（比表面积０．５２ｍ^２／ｇ,中位粒径２０．４μｍ）进行了一系列粉碎实验,研究了气流粉碎次数、成形压力和烧结温度对烧结密度的影响．结果表明,当粉碎次数达到３次后,可获得＜１μｍ的Ｂ_４Ｃ超细粉末．经过４次气流粉碎的Ｂ_４Ｃ超细粉末的比表面积为２．５３ｍ^２／ｇ,中位粒径为０．５６μｍ;粉末分别于２２００和２２５０℃压烧结１ｈ,其烧结密度分别达到理论密度的７８．６％和８２．５％,平均晶粒尺寸分别为２８和５０μｍ抗压强度分别为３９０和５５５ＭＰａ．     

砂磨粉碎制备SiC超细粉体

砂磨粉碎是制备超细陶瓷粉体的有效途径之一 ,避免了传统球磨、酸洗工艺对环境的污染。本文采用砂磨粉碎工艺制备 Si C超细粉体 ,研究了砂磨粉碎制备过程中料浆固含量、球料比和砂磨时间等工艺条件对粉体尺寸和尺寸分布的影响 ,在一定工艺条件下 ,将中位粒径为 7.3μm的高纯 Si C粗粉砂磨粉碎 1 8hr,得到了中位粒径为 0 .4 7μm、粉体尺寸分布范围窄、氧含量小于1 .5wt%的超细 Si C粉体。     

气流粉碎干燥制备超细磷酸铁锂粉的工艺

采用LNJST-120HT型闭路循环氮气保护气流粉碎分级系统对磷酸铁锂粉进行超细加工、干燥;对粉碎、分级、收集、输送和包装系统的操作参数、设备结构及系统运行过程中出现的流动性、水分增加等问题进行分析探讨,并优化改进;通过加工超细磷酸铁锂粉的工业试验,对改进后的超音速气流磨进行测试。结果表明,控制螺杆加料机和分级机转速分别为62和1 072 r/min,气源压力和温度分别为0.5 MPa和120℃,包装房露点温度控制在-20℃以下,磷酸铁锂粉成品水分含量维持在0.35‰~0.55‰,成品粒径d_(50)=0.8~1.2μm、d_(100)<8μm,产量为200~230 kg/h。     

超细木炭粉的制备及其性能

以中值粒径为287μm的粗木炭粉为原料,以不锈钢球为磨介,采用球磨粉碎法制备超细木炭粉;优化双向旋转球磨机的工作参数;测试和表征粗木炭粉和超细木炭粉的粒径分布、比表面积和微观形貌;研究炭粉超细化对其碘吸附值以及无硫黑火药热分解性能的影响。结果表明:以直径为10 mm的不锈钢球为磨介,双向旋转球磨粉碎机制备超细木炭粉的最佳工作参数为:磨球体积与筒体容积之比为0.7、球料质量比为10∶1、球形筒体转速为120 r/min、搅拌器转速为80 r/min、粉碎时间为6 h;采用最佳工作参数制备的超细木炭粉粒径约为2.30μm,粒径分布较窄,比表面积可达到852.01 m~2/g;超细木炭粉的碘吸附值可达到1 049 mg/g,更易于吸附小分子杂质;相比于粗木炭粉,以超细木炭粉制备的无硫黑火药的热分解温度降低了30℃左右,热分解放热峰温度降低了50℃左右,细化炭粉粒径能够有效提升无硫黑火药的点火性能。     

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.