基于Windows平行文件系统下的平行I/O

近年来,平行档案系统被广泛的用来解决这个问题,除此之外,由于电脑被使用于平行处理平台的普及率逐步上升,造成使用于电脑上的平行处理软体需求量持续增加,但是,却有可能缺乏平行I/O的系统。因此,文章旨在研究与分析Windows平行文件系统下的平行I/O的特点与实现方式。     

Catalysts for the selective dehydrogenation of high molecular weight paraffins

Selective dehydrogenation of high molecular weight linear paraffins is an important process step for the production of biodegradable detergents. Pt, PtSn, PtGe and PtPb supported on -A1₂O₃ doped with alkaline metals were characterized and tested in then-decane dehydrogenation reaction. When alkaline metals are added to Pt/Al₂O₃ a promoting effect on the selectivity to olefins in then-decane dehydrogenation is observed. Regarding PtSn/Al₂O₃ -doped catalysts their performance depends on the alkaline metal used as dopant, the Sn content and the preparation method. Moreover these bimetallic catalysts show a better olefin yield and a lower selectivity to gases and aromatics than the monometallic platinum catalysts. PtGe and PtPb based catalysts have an analogous behavior to the PtSn one but its selectivity to olefins is lower.     

Calculation of single adsorption isotherms from gravimetrically measured binary gas mixture adsorption isotherms on activated carbon at high pressures

A method is developed for the calculation of single-component adsorption isotherms from gravimetrically measured binary gas mixture adsorption isotherms at high pressures, at two temperatures and for different mole fractions of the gas phase. The adsorption of nitrogen/methane on active carbon Norit R1 is taken as an experimental example.     

偶联剂与甘蔗渣／PVC复合材料性能的研究

分别用硅烷偶联剂KH560和钛酸酯偶联剂NDZ311对甘蔗渣/PVC复合体系进行处理。研究了两种处理方法对甘蔗渣/PVC复合材料力学性能、界面形态、耐水性能和加工性能的影响。结果表明,与未处理的相比,两种处理方法都改善了甘蔗渣和PVC之间的界面相容性,界面黏结得到增强,使复合材料的强度和韧性有了较大的提高,同时改善了甘蔗渣/PVC复合材料的加工性能。钛酸酯偶联剂处理对甘蔗渣/PVC复合材料性能的影响更为显著,当其用量为1%时,复合材料的拉伸强度和冲击韧性均得到提高,其中拉伸强度提高了55%。     

Poly(styrene-b-isobutylene-b-styrene) block copolymer ionomers (BCPI) and BCPI/silicate nanocomposites. 2. NaBCPI sol-gel polymerization templates

Polystyrene (PS) blocks in poly(styrene-b-isobutylene-b-styrene) (PS-PIB-PS) block copolymers were partially sulfonated and the acid groups converted to Na⁺SO₃⁻ groups to create ionomers. Then, dimethylacetamide was used to selectively swell the ionic PS domains and the swollen films were exposed to sol-gel reactive tetraethylorthosilicate solutions. (EtO)_4−xSi(OH)_x monomers then permeated films so that sol-gel reactions occurred within/around the ionic PS domains. Environmental scanning electron microscopy/energy dispersive X-ray spectroscopy investigations showed that silicate structures can be incorporated within the interior of the ionomer films. Differential scanning calorimetry studies indicated that there is no variance in the PIB block T_g with respect to ionomer formation, or with respect to silicate loading of the ionomer at low levels, which suggests that the silicate component does not reside in the PIB phase. ²³Na solid state NMR spectroscopy detected isolated Na⁺SO₃⁻ groups as well as aggregated SO₃⁻Na⁺ ion pairs for ‘as cast’ and ‘dry’ non-silicate containing ionomer samples. In a hydrated sample, almost all Na⁺ ions were solvent-separated. AFM analysis showed that phase separation exists, but that the degree of order is significantly less than that for hybrids based on the corresponding benzyltrimethylammonium ionomer. This frustrated morphology was also seen in the results of small angle X-ray scattering experiments. Given the scale of organic/inorganic heterogeneity, these hybrids are properly classified as nanocomposites.     

A Thermo-Mechanical Study of Some Epoxy Adhesives Subjected to Combined Dynamic and Static Stresses

The object of the present study was to investigate the effect of superimposed dynamic and static stresses on mechanical and thermal properties of some epoxy adhesives. It was found that combinations of shear creep and torsional oscillations, applied simultaneously to adhesive joints at temperatures within the glassy range of the adhesive, led to strengthening of the joints in shear and to an increase in the glass transition temperature of the adhesive. Similar loading stresses applied at temperatures close to the T_g of the adhesive, led to opposite effects on the above mentioned properties of the joints. The width of the glassy-rubbery transition of the adhesives increased, in the whole range of temperatures used in this study and for all epoxy compositions, as a result of subjecting the joints to superimposed dynamic and static stresses. The broadening of the glass transition was interpreted as a result of the stiffening of polymer network during the combined stressing experiments. A linear relationship was found between the area of endothermal peaks in the first DSC scan of specimens subjected prior to test to superimposed dynamic and static stresses at temperatures below T_g, and the shear strength of the joints. In agreement with this observation and with literature data, a linear relationship was revealed also between the glass transition temperature of the resins (measured in the first DSC scan) and the shear strength of the joints. Based on experimental observations and on some literature information, it was suggested that the strengthening of the joint, as well as the changes in thermal properties of the adhesives, are mainly due to physical processes, such as short-range orientation of network chains and an increase in intermolecular interaction between highly polar sites of the network. The possibility that superimposed stressing led to changes in chemical crosslinking was discussed but it seems that no such reactions occurred.     

钩端螺旋体黄疸出血群赖株LipL41基因的克隆表达及鉴定

目的　对钩体黄疸出血群赖株LipL4 1基因进行克隆、表达及鉴定。方法　采用高保真PCR ,从我国钩体黄疸出血群赖株基因组中扩增全长LipL4 1基因片段 ,并构建原核表达系统。结果　所克隆的LipL4 1基因核苷酸和氨基酸序列与已发表LipL4 1基因序列 (GenbankL4 6 794 )同源性分别为 96 2 5 %和 98 87% ;所表达的目的蛋白经Westernblot证实为具有良好免疫反应性的广谱抗原。结论　可作为研制基因工程疫苗的候选抗原     

Aging characteristics of high-power lithium-ion cells with LiNi0.8Co0.15Al0.05O2 and Li4/3Ti5/3O4 electrodes

The impedance rise that results from the accelerated aging of high-power lithium-ion cells containing LiNi_0.8Co_0.15Al_0.05O₂-based positive and graphite-based negative electrodes is dominated by contributions from the positive electrode. Data from various diagnostic experiments have indicated that a general degradation of the ionic pathway, apparently caused by surface film formation on the oxide particles, produces the positive electrode interface rise. One mechanistic hypothesis postulates that these surface films are components of the negative electrode solid electrolyte interphase (SEI) layer that migrate through the electrolyte and separator and subsequently coat the positive electrode. This hypothesis is examined in this article by subjecting cells with LiNi_0.8Co_0.15Al_0.05O₂-based positive and Li_4/3Ti_5/3O₄-based negative electrodes to accelerated aging. The impedance rise in these cells was observed to be almost entirely from the positive electrode. Because reduction products are not expected on the 1.55 V Li_4/3Ti_5/3O₄ electrode, the positive electrode impedance cannot be attributed to the migration of SEI-type fragments from the negative electrode. It follows then that the impedance rise results from mechanisms that are “intrinsic” to the positive electrode.     

Synthetic polymeric absorbent for dye based on chemically crosslinked acrylamide/mesaconic acid hydrogels

Adsorption properties of copolymers of acrylamide and mesaconic acid (CAME) in aqueous Basic Blue 12 (Nile blue chloride) solution have been investigated. Chemically crosslinked CAME hydrogels with various compositions were prepared from ternary mixtures of acrylamide (A), mesaconic(ME) acid, and water by free radical polymerization in aqueous solution, using a multifunctional crosslinker such as ethylene glycol dimethacrylate (EGDMA). Dynamic swelling tests in water was applied to the hydrogels. Weight swelling ratio (S) values have been calculated. Sorption of Basic Blue 12 (BB 12) onto CAME hydrogels was studied by batch sorption technique at 25°C. In the experiments of the sorption, L type sorption in the Giles classification system was found. Some binding parameters such as initial binding constant (K_i), equilibrium constant (K), monolayer coverage (n), site‐size (u), and maximum fractional occupancy (Ô) for CAME hydrogels‐BB 12 binding system were calculated by using Klotz, Scatchard, and Langmuir linearization methods. Finally, the amount of sorbed BB 12 per gram of dry hydrogel (q) was calculated to be 2.28 × 10^?6–7.91× 10^?6 mol BB 12 per gram for hydrogels. Sorption % was changed range 16.09–58.86%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 405–413, 2006     

汽车用胶带的材料进展

介绍汽车用胶带的材料进展。目前汽车用胶带的胶料主体材料主要为CR和氢化丁腈橡胶，乙烯一丙烯酸酯橡胶和热塑性EPDM的应用研究正在进行；线绳主要为聚酯线绳、玻璃纤维线绳和芳纶线绳；包布主要为平纹帆布、广角帆布和高弹性包布；短纤维主要为预处理锦纶短纤维、木质素短纤维、聚酯短纤维和棉短纤维。我国汽车用胶带材料已实现了氯丁化、线绳化和短纤维化的目标，但材料性能和构成与国外相比差距仍然较大，胶带质量和档次有待提高。