Preparation of Superfine Fe_3O_4 Cubic Powders

A kind of superfine Fe_3O_4 cubic powder has been prepared chemi- cally.Its formation is related with the concentration of Na^(+1) in the chemical reaction.Given the same particle size,a superfine Fe_3O_4 cubic powder has a higher H(?) and lower σ,than one made up of spherical Fe_O_4.

Preparation and Characterization of CeO_2 Superfine Powder

The CeO_2 superfine powder was prepared by the co-precipitation method, using the industrial grade Ce_2(CO_3)_3 and NH_4HCO_3 as starting material and precipitating reagent, respectively. The precipitated precursons and the calcinated products were characterized by the thermogravimetric analysis/thermoanalysis (TGA/DTA), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The results show that using NH_4HCO_3 as a precipitating reagent, the precipitate decomposed full as it was heated to 360 ℃. The CeO_2 superfine powder formed by calcinating the precipitate belongs to a cubic CaF_2-type structure and has the first mean particle diameter 140 nm and second mean particle diameter 630 nm. The CeO_2 powder particles aggregate and grow with raising the calcination temperature.

Improving performance of recycled aggregate concrete with superfine pozzolanic powders

Phosphorous slag （PHS）, ground granulated blast-furnace slag （GGBS） and fly ash （FA） were used as replacements of Portland cement to modify the microstruc^xe of recycled aggregate concrete （RAC）. A new manufacturing method named ＂W3T4＂ was proposed to improve the performances of interracial transition zone （ITZ） between recycled aggregate and mortar. The mechanical properties and the durability of RAC were tested, which show that this new manufacturing method improves the properties of RAC, and the GGBS with finest size makes a great contribution to the performance of RAC due to its better filling effect and much earlier pozzolanic reaction. Combined with GGBS, the effects of PHS on the retardation of setting time can be alleviated and the synergistic effect helps to make a more compact RAC. For the RAC with 25% of the recycled aggregate （RA） replacement and 10% PHS ＋ 10% GGBS additives, the compressive strength increases by 25.4%, but the permeability decreases by 64.3% with respect to the reference concrete made with nature aggregates. The micro-mechanisms of these improvements were investigated by the scanning electron microscope （SEM）. The SEM images show that the new manufacturing method, adding superfine pozzolanic powders and super-plasticizer benefits, makes a much denser ITZ in RAC.

Influences of four processing methods on main nutritional components of foxtail millet: A review

Foxtail millet, originated from China and now cultivated worldwide, is a kind of high dietary fiber whole grain food, and has a high level of vitamins and proteins. Furthermore, foxtail millet has many positive effects on the adjuvant treatment of diabetes, cancer, and cardiovascular diseases because of the abundance in polyphenols. Nonetheless, foxtail millet has poor processing characteristics due to the absence of gluten, restricting the development of foxtail millet products. Studies have demonstrated that heat-moisture treatment, extrusion, superfine grinding, and microbial fermentation are promising methods to improve the processing qualities of foxtail millet. Heat-moisture treatment is helpful to increase the content of resistant starch but has less influence on other components, further reduce the GI value of foxtail millet. The extrusion has positive effects on improving the solubility of foxtail millet starch and increasing the contents of polyunsaturated fatty acid, linoleic and linolenic acids, and adverse effects on reducing the solubility of foxtail millet proteins and causing losses of nutrients due to Maillard reaction. Superfine grinding can reduce the particle size of foxtail millet to obtain a better mouthfeel of foxtail millet products. The superfine foxtail millet flour has better solubility, higher freeze-thaw stability, and lower gelatinization temperature. Microbial fermentation contributes positively to reducing the molecular weight and retrogradation value of foxtail millet starch, degrading rapidly digested starch, and improving the digestibility of foxtail millet protein. This paper briefly introduced the effects of different processing methods on foxtail millet nutrients, aiming to provide references for increasing the variety and improving the quality of foxtail millet products.

Effect of Superfine Grinding on Physicochemical Properties, Antioxidant Activity and Phenolic Content of Red Rice ( <i>Oryza sativa</i>L.)

Red rice gains popularity as a functional crop owing to its high polyphenols content and antioxidant activity. However, active components are discarded in common milling. Superfine ground technology was employed in this paper. To evaluate the influence of superfine ground processing on the physicochemical properties and functional effect of red rice (Oryza sativa L.), four powders with the size of 156.74 μm, 69.53 μm, 26.35 μm, and 10.68 μm were prepared by superfine grinding technology in this paper. Results showed that the size was smaller for red rice powders, greater for the bulk density (from 0.624 g/ml to 0.745 g/ml), and smaller for the angle of repose (from 74.67&deg;to 61.41&deg;) and slide (from 38.99&deg;to 26.42&deg;). The values of water solubility index, water holding capacity and enzymatic digestibility by α-amylase significantly increased with the decreasing particle size (P < 0.05). In addition, antioxidant activity and phenolic content were enhanced by superfine ground. These results indicated that superfine ground would improve the physicochemical and functional properties of red rice, which was helpful to promote the overall quality and healthy effect of foods containing red rice.

A New Method for Improving Strength and Plasticity of Steel Wire

Specially designed wire-drawing equipment with multiple electropulse generator was introduced. The influences of multiple electropulses processing on the microstructure and properties of the hardened steel wire were investigated. Samples treated by direct current under the same current density as that in multiple electropulses processing were carried out for contrast analysis. The results show that the optimized parameters of multiple electropulses processing will be facilitated to increase the nucleation rate and slow down the growth rate of recrystallized grains. Consequently, massive superfine grains of micro and sub-micro scale could be found in the steel wire. Thereby, the elongation was significantly enhanced with a relatively small strength reduction in comparison with as-received cold-drawing steel wires. Outstanding mechanical properties of steel wire were obtained.

Protective effects of Purendan superfine powder on retinal neuron apoptosis in a rat model of type 2 diabetes mellitus

This study sought to investigate the effects of Purendan superfine powder comprised of Momordica charantia, Radix Ginseng, and Radix Salviae Miltiorrhiae on neuronal apoptosis and expression of bcl-2, bax, and caspase-3, which are retinal apoptosis-associated factors in rats with diabetes mellitus induced by continuous intraperitoneal injection of streptozotocin. The results showed that Purendan superfine powder could upregulate the expression of bcl-2 protein and mRNA, and downregulate the expression of bax and caspase-3 in the retina of diabetes mellitus rats. In addition, Purendan superfine powder was shown to reduce the number of apoptotic neurons. Our experimental findings indicate that Purendan superfine powder can inhibit neuronal apoptosis in the retina of diabetes mellitus rats and has protective effects on diabetic retinopathy.

Optimization of the Production Process of Flash-Spinning UHMWPE Superfine Fiber by Response Surface Methodology

In this paper, statistical optimization method was used to optimize the flash-spinning process conditions. Ultra-high molecular weight polyethylene （UHMWPE） superfine fiber was fabricated by flash-spinning method using UHMWPE as the fiberforming polymer, 1, 2-dichloroethane as the main solvent. The important parameters of the flash-spinning were filtered by Plackett-Burman experimental design based on the single factor experiments. After determining the best regions of the fiber properties, the optimum level of the important parameters were determined by Box-Behnken design. The results of the design showed that the important parameters influencing on the properties of the flash.spinning fiber were spinning temperature, spinning pressure, and spinning solution concentration. The optimum technical parameters were： spinning temperature 186. 4 ~C, spinning pressure 6. 16 MPa, spinning solution concentration 3.06 %. The highest combination property of the flash-spinning fiber was 86.39 under this condition.

In Vivo Histocompatibility Evaluation of Polyurethane Membrane Modified by Superfine Silk-fibroin Powder

In this study, a novel polyurethane membrane, modified by superfine silk-fibroin powder, was prepared for small-diameter vascular grafting. Scanning electron microscopy, transmission electron microscopy, and histological examination were applied to evaluate histocompatibility of this polyurethane membrane. The polyurethane membrane was compared with polytetrafluoroethylene material. A pseudomembrane and gap formed between polytetrafluoroethylene and the surrounding tissues, and no cells infiltrated or grew into the polytetrafluoroethylene material. On the contrary, superfine silk-fibroin powder/polyurethane blend membrane merged tightly with the surrounding tissues without gaps, and cells infiltrated and grew into the material. Moreover, the negative effects of superfine silk-fibroin powder/polyurethane blend membrane on cells were less than those of its polytetrafluoroethylene counterpart. Our findings indicated that the superfine silk-fibroin powder/polyurethane blend membrane has better histocompatibility than polytetrafluoroethylene membrane. It is concluded that the superfine silk-fibroin powder/polyurethane blend membrane is a promising biomaterial for small-diameter prosthesis.

钛酸钡锶复盐超微陶瓷粉末制备以及粉末结构测定

本文首次报道采用简单低耗的有机介质化学共沉淀法,制备超微陶瓷粉末钛酸钡锶复盐(Ba_xSr(1-x)TiO_3)。由扫描电镜观测其平均粒径在0.45μm以下。由X-粉晶衍射图得到,该复盐粉末属于BaTiO_3(四方)与SrTiO3(立方)的混晶。

NEAR RAPID DIRECTIONAL SOLIDIFICATION AND ITS SUPERFINE MICROSTRUCTURE

This paper briefly reviews the recent research on the near rapid directional solidification and microstructure superfining. The morphology transitions and the corresponding mechanical properties are presented. The critical velocities relevant to the morphology transitions are comprehensively given. Meanwhile the solidification characteristics near absolute stability limit are studied.It can be clearly seen that the superfine microstructures possess extremely better properties compared with the conventional microstructures.

Preparation of Superfine-Cemented Carbide by Spark Plasma Sintering

92WC-8Co puwder mixture with superfine-tungsten carbide was respectively sintered by spark plasma sintering（ SPS ） and sintering isostutic pressure （SIP）. Complete dense samples with 200 nm WC grains and 94.2HRA hardness were prepared by spark plasma sintering at 1 150 ℃ and under 4.5 kN for 5 minutes. SIP was carried out at 1 400 ℃ for 30 minutes with a result of 300-400 nm WC grains and 93 HRA hardness. The results show that sintering temperature is greatly decreased by SPS, sintering time is largely shortened and WC grain growth is effectively retarded. Micropores and drawb（wks in superfine-cemented carbide made by SPS are greatly declined, which is very useful to improving nwehanical properties.

Discussion on the Application of LS-DYNA in Superfine Grinding of Wheat Bran

Superfine grinding, involving the fragmentation mechanism of wheat bran cell tissue, is being employed by milling industry. In order to determine the effect of wheat bran cell tissue on the fragmentation mechanism when using superfine grinding,a technical scheme of the nonlinear finite element numerical simulation method based on LS-DYNA is proposed in this paper.The physiological characteristics of wheat bran structural layers including outer pericarp, intermediate layer and aleurone layer are examined first, and then the mechanical properties of wheat bran structural layers and their effects on the super fine grinding process are analyzed. Secondly, the explicit time integration algorithm of LS-DYNA is introduced, and the application feasibility of LS-DYNA in the analysis of wheat bran superfine grinding mechanism is discussed. Finally, the specific application of LS-DYNA in the determination of grinding form and load, the selection and design of the grinding media and the selection of grinding temperature are discussed in detail in the process of superfine grinding for wheat bran cell tissue. The above research provides a theoretical basis for selecting and developing the equipment and technology suitable for wheat bran superfine grinding, and lays a theoretical foundation for enhancing the quality and efficiency of wheat bran superfine grinding.

Wool characteristics of crossbred Baghdadi wild ram and Iran native sheep

Twenty mid side wool samples of crossbred sheep were collected and their characteristics were determined. Data analyzed by SAS software and Duncan’s multiple range tests was used for comparison of mean wool characteristics. Average fleece weight, yield, wool diameter, Fine fiber and staple length were: 431.59 ± 38.95 gr, 65.14%, 14.24 ± 0.67 μm, 48.67 ± 5.59, and 43.65 ± 4.15 mm respectively. Mean fleece weight was significantly affected (p 1 and F2 generation 11.84 ± 0.58, 16.27 ± 0.72 μm respectively. There were effective differences among ages (12.55 ± 0.74, 14.47 ± 0.58 and 13.11 ± 0.64 μm for 1, 2 and 3 yr old respectively). Wool diameter of younger animals, males and F1 was so fine (12.55, 12.87 and 11.84 μm respectively). Staple length of F2 crosses was significantly longer than F1 crosses (p 1 was significantly finer than F2, but length and down fiber percentage was less than second generation. As wild sheep shed his fiber in winter, the first filial crosses also shed their fibers from the end of winter to early spring. Shedding was seldom observed in F2 generations. It seems likely that wool from crossbred sheep could be used for those applications for which cashmere is suitable. This study indicates that, such crossbred sheep have a superfine wool and could be used in pure or blend for textile industry.

Packing Density Improvement through Addition of Limestone Fines, Superfine Cement and Condensed Silica Fume

Adoption of a low water/powder (W/P) ratio is the key to improve the strength and durability of concrete, which relies on a high packing density because fresh concrete requires excess water to offer flowability. To obtain a high packing density, powders with different particle sizes, including limestone fines (LSF), superfine cement (SFC), condensed silica fume (CSF), were added to the cement paste and the resulting packing densities were measured directly by a newly-developed wet packing test. Results demonstrated that addition of powders with a finer size would more significantly improve the packing density but the powders should be at least as fine as 1/4 of the OPC to effectively improve the packing density. Packing density and voids ratio relationship showed that a small increase in packing density can significantly decrease the voids ratio, which could allow the W/P ratio to be reduced to improve the strength and durability of the concrete without compromising the flowability.

Mechanical Properties of Small-diameter Superfine Silk Powder/Polyurethane Vascular Graft Reinforced by Tubular Knitted Fabric

In this paper,a kind of composite microtube,which is made from superfine silk powder and polyurethane,reinforced by polyster and spandex tubular fabrics,was examined.The cross-section of composite microtubes were microporous,and micropores were uniform distributed,the inner surface was relatively smooth.The results showed that the wall thickness of composite microtubes increased,which led to the strength,the breaking work and the initial modulus incresead;that the spandex content increased brought about the initial modulus and the breaking work decreased,but the breaking extension and the breaking load were firstly increased and then decreased;and all the mechanical properties decreased as the SFSP content increased.

Research into Exploitation and Application of Three Sorts of

In this paper the authors introduce their past years’study results about the exploitation and application of three sorts of nontraditional nonmetal minerals. In this research, the main aspects and techniques of basic study for the exploitation and application are summarized, and some key science and technological problems are proposed as the objects of their future research.

Defects in aluminum foam with superfine open-cell structure

The infiltration casting process for producing aluminum foam includes three steps： preparing precursor using NaCI particles, infiltrating molten aluminum and cleaning NaCI precursor. Defects occur during the preparation of aluminum foam with superfine open-cell structure, and influence the pore structure and performance of aluminum foam materials. The types of the defect and their forming mechanisms are analyzed in this paper. The defects include point defects and linear metal defects, and are caused by the defects in salt precursor and the insufficient infiltration of molten aluminum into precursor. With the choice of proper precursor preparation method and infiltration process parameters, the complete aluminum foam with superfine pores could be achieved.

Effect of Superfine Slag Powder on HPC Properties

A superfine slag powder (SP) made from granulated blast furnace slag incorporating activators by using special millingtechnique, was used as supplementary cementitious material in high performance concrete (HPC), replacing part ofthe mass of normal Portland cement. The effects of the SP on the workability, mechanical and crack self-healingproperties of HPC were studied. The hydration process and microstructure characteristics were investigated by X-raydiffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The crack self-healing capacitywas evaluated by Brazilian test. The test results indicate that the SP has especially supplementary effect on waterreducing and excellent property of better control of slump loss. The concrete flowability increases remarkably withthe increase of SP replacement level in the range of 20% to 50%. The compressive and splitting tensile strengthsof HPC containing SP are higher than the corresponding strength of the control concrete at all ages. The crackself-healing ability is highly dependent on SP content of HPC.

Mathematical Index for Evaluating Disperse Dyes Levelness of Superfine Polyester Fabric

The dyeing deference between the superfine and the con-ventional polyester fabric is discussed. The major threefactors affecting the level dyeing property of superfinepolyester-initial adsorption rate, desorption rate andinterface migration rate of dyestuffs at 70℃ are studied.The levelness improves considerably with decreased ini-tial adsorption rate, increased desorption rate and inter-face migration rate. And then a mathematical indexbased on them is established. The evaluation to dispersedyes resulting from it corresponds with their perfor-mance during industrial process. As new definitions, ini-tial adsorption rate and desorption rate of dyestuffs arefirstly introduced.