黑索今超细化技术研究

文章针对如何实现超细黑索今（RDX）的安全连续批量生产问题,提出了采用卧式搅拌球磨机制备超细RDX粉体的工艺方法,介绍了卧式搅拌球磨机粉碎原理,详细分析了卧式搅拌球磨机搅拌器转速、研磨时间、磨球种类、介质球填充率及RDX浆料浓度等工艺参数对超细RDX粉体产品粒度的影响。试验结果表明：搅拌球磨这种粉碎方式能制备粒度为D90=3．05μm的超细RDX粉体产品,工艺安全可控,产品质量稳定。这种超细RDX粉体产品能满足高性能炸药及高能推进剂的需要。     

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。     

煤直接液化用黄铁矿催化剂超细粉碎的研究

采用粒度、XRD、IR等检测手段对煤直接液化用黄铁矿催化剂的超细粉碎进行了研究,分析了超细粉碎,包括干磨和湿磨两种不同粉碎方式,对粉体粒度、结构和性质变化的影响,及其对催化效果可能产生的影响.结果表明,超细粉碎黄铁矿时,湿磨的粉碎效果比干磨好;超细粉碎使黄铁矿粉体晶粒尺寸减小,晶格发生畸变,畸变率较小;超细粉碎使黄铁矿中的硫部分氧化成了硫酸根,湿磨过程中的氧化程度比干磨的小.从粉碎效率,粒度分布及氧化程度来考虑,制备粒度为1μm左右的煤直接液化用黄铁矿催化剂采用湿磨的方式较好.     

过氯乙烯树脂超细粉碎技术

为了解决过氯乙烯树脂粒径过大,致使其在涂料中的附着力较小以及在涂料表面的光洁度较低、遮盖力较小的问题,采用双圆盘剪切粉碎机对过氯乙烯树脂进行超细粉碎,研究粉碎过程中物料浓度、粉碎次数、刀片间距、磨盘转速等工艺参数对过氯乙烯树脂粒度的影响。结果表明:最佳粉碎条件为物料流中过氯乙烯树脂的质量分数为20%,循环粉碎4次,磨盘转速为2 000 r/min,刀片间距为0.5 mm;在最佳粉碎条件下,粉碎工艺稳定,过氯乙烯树脂中位粒径d50由约292μm变为约96μm,能满足涂料的使用要求。     

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。     

煤粉超细化技术及设备研究

根据双向旋转球磨机的超细粉碎原理,研究开发制备超细煤粉的技术及设备,并采用该设备进行煤粉的超细粉碎实验,分析各种工艺参数对超细煤粉产品粒度影响。结果表明:采用双向旋转球磨机制备超细煤粉的最佳工艺条件为:筒体及搅拌器转数25r/min,球料质量比为8,研磨时间为4～5h,磨球尺寸为10～20mm,制备出超细煤粉产品的粒度为d50=1.15μm,d90=2.67μm。     

水镁石粉湿法超细制备和表面改性一体化研究

由于粉体在进行超细粉碎后，比表面积增大，表面能升高，颗粒极易团聚，在进行表面改性后，所得粉体有很多大颗粒团聚体。运用行星式高能球磨机，在球磨过程中加入助磨剂，促进颗粒的分散，同时加入表面活性剂，将粉体进行表面改性，一改以前将粉体超细后再进行表面改性，避免了粉体的二次团聚。使用激光粒度分析仪、扫描电子显微镜（SEM）、接触角测定仪等现代分析检测技术对粉体的粒径、形貌和表面性质进行了表征。结果表明，这种超细和改性一体化的处理方法能显著降低水镁石粉的粒度分布并使其形貌均匀，在研磨20min后粉体粒径就降到0．51μm以下，改性后的粉体活化指数高。     

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     

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。     

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。     

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.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

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.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

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.