Cube cluster approximation for the spin glass in the simple cubic lattice

The spin glass in the random-bond Ising model on a simple cubic lattice is considered. A simple method to calculate the partial trace of the density matrices of a fairly large cluster by use of the REDUCE system is presented. The phase diagram showing the paramagnetic, ferromagnetic, antiferromagnetic and spin glass states is obtained for the ±J model on the simple cubic lattice by the cube cluster approximation. The spin glass transition temperature is obtained with the inclusion of enough frustration of the cube clusters, and kTg/J=0.9850 for p (the concentration of the +J bond) = 1/2.     

Preparation of a silica gel–carbon black composite by the sol–gel process in the presence of polymer-grafted carbon black

This paper is concerned with the preparation of a silica gel–carbon black composite by the sol–gel process, which consists of tetraethoxysilane and polymer-grafted carbon black. Polymer-grafted carbon black was synthesized by three methods: (1) cationic polymerization of N-vinyl-2-pyrrolidone, (2) cationic ring-opening polymerization of 2-methyl-2-oxazoline, and (3) radical polymerization of glycidyl methacrylate followed by reaction of glycidyl groups in the grafted polymer chains with 3-aminopropyltriethoxysilane. The polycondensation of tetraethoxysilane proceeded under acidic conditions in the presence of polymer-grafted carbon black to give a deep black silica gel–carbon black composite. The more the content of untreated carbon black was increased, the more the gelation time was shortened. On the contrary, gelation was retarded by grafted polymer chains on the carbon black surface in the case of polymer-grafted carbon black. The scratch hardness of the resulting silica gel–carbon black composite was almost equal regardless of the carbon black content in the presence of untreated carbon black, whereas it was liable to decrease as the content of polymer-grafted carbon black increased. The solvent adsorption properties of the silica gel–polymer-grafted carbon black composite varied with the solubility of grafted polymer chains on the carbon black surface towards the immersion solvent. © 1998 Chapman & Hall     

Phase transformation kinetics of precursor gel to α-alumina

The kinetic analysis of the transformation of gels to -alumina in the Al (OPr ⁱ )₃-Al(N0₃)₃-(citric acid) system, was studied; the relationship between -alumina and the gel structure, presumed from the solution structure and the transformation to -alumina by calcination, was also investigated. It was shown that the gel structure effects the formation of -alumina nuclei and their growth. The former was confirmed by the apparent activation energy obtained from incubation time, namely the gel obtained from the spinnable solution showed a smaller apparent activation energy than that from the unspinnable solution. Evidence for the latter was derived from the apparent activation energy, obtained from annealing time. That is, contrary to above, the gel obtained from the spinnable solution showed a larger apparent activation energy. However, the gel structure did not affect the manner of crystal growth. These phenomena can be explained by the difference in gel structure, i.e. by the kind of Al-O structure it is composed of, and by the conditions of formation of the -alumina grains in the first place.     

Peak shift characteristics for barium ferrite flexible disk drive

Output waveform and peak shift characteristics for low squareness Ba-ferrite perpendicular recording flexible disk (FD), the same as used for 3.5 inch Ba-ferrite 4MB FDD, were investigated by both calculation and measurement. A simple simulation for an isolated pulse and density responses was carried out and an estimation method for the perpendicular component factor, Kp, was derived. The peak shift characteristics and Kp for a Ba-ferrite FD were investigated for various recording /reproducing conditions, such as head gap length, recording current, etc. Then, it is shown that both the Kp value and peak shift are not so large, and therefore a phase equalizer is not needed for the low squareness Ba-ferrite FD.     

Risk factors for sensitisation to methyltetrahydrophthalic anhydride

OBJECTIVES: To examine an association between specific IgE to methyltetrahydrophthalic anhydride (MTHPA) and exposure time, atopic history, smoking habits, and total IgE concentrations. METHODS: A cross sectional survey was carried out on a population of 148 workers from two condenser plants using epoxy resin with MTHPA, an acid anhydride curing agent known to cause allergy. RESULTS: Using a Pharmacia CAP system with a MTHPA human serum albumin conjugate, specific IgE antibody was detected in serum from 97 (66%) out of the 148 workers exposed to MTHPA. Stepwise multiple linear regression analysis showed a striking relation between log concentrations of specific and total IgE (P < 0.0001). Furthermore, when the workers were divided into two groups according to a cut-off point (100 IU/ml) between low and high total IgE, current smoking was significantly (P = 0.025) associated with specific IgE production only in the group with low total IgE (< 100 IU/ml). CONCLUSIONS: Smoking is the most significant risk factor for raising specific IgE to MTHPA in the group with low total IgE concentrations.     

Distribution of dystrophin and dystrophin-associated protein 43DAG (beta-dystroglycan) in the central nervous system of normal controls and patients with Duchenne muscular dystrophy

The measurement of combustion gases produced by burning aircraft cabin materials poses a continuing limitation for smoke toxicity research. Because toxic effects of gases depend on both their concentrations and the duration of exposure, frequent atmosphere sampling is necessary to define the gas concentration-exposure time curve. A gas chromatographic (GC) method was developed for the simultaneous analyses of carbon monoxide (CO), hydrogen sulfide (H2S), sulfur dioxide (SO2), and hydrogen cyanide (HCN). The method used an MTI M200 dual-column gas chromatograph equipped with 4-m molecular sieve-5A and 8-m PoraPlot-U wall-coated capillary columns and two low-volume, high-sensitivity thermal conductivity detectors. Detectability (in parts per million [ppm]) and retention times (in seconds) for the gases were as follows: CO, 100 ppm, 28 s; H2S, 50 ppm, 26 s; SO2, 125 ppm, 76 s; and HCN, 60 ppm, 108 s. The method was effective for determining these gases in mixtures and in the combustion atmospheres generated by burning wool (CO, HCN, and H2S) and modacrylic fabrics (CO and HCN). Common atmospheric gaseous or combustion products (oxygen, carbon dioxide, nitrogen, water vapor, and other volatiles) did not interfere with the analyses. However, filtration of the combustion atmospheres was necessary to prevent restriction of the GC sampling inlet by smoke particulates. The speed, sensitivity, and selectivity of this method make it suitable for smoke toxicity research and for evaluating performance of passenger protective breathing equipment. Also, this method can potentially be modified to analyze these gases when they are liberated from biosamples.     

烧结钢的应力-弹性及塑性应变曲线的制作与评价

根据拉伸试验(TT)得到的应力-应变曲线和通过声音脉冲方法(APM)得到的声速,计算并比较了烧结钢的弹性模量(E)和泊松比(v).Err和vTT的值分别小于EAPM和vAPM,这是因为在烧结钢的应力-应变中不仅包含了弹性应变,而且也包含了塑性应变.利用由EAPM和vAPM的值计算得到的纵向和横向弹性应变,从纵向和横向应力-应变中分离出纵向和横向的塑性应变.在小应变时烧结钢没有显示线性应力-应变的情况下,可以很简单地由纵向塑性应力表中求出弹性极限或0.2%的屈服强度.对于同样的应力,每个样品的弹性应变和塑性应变的不同,可以由基于孔隙特征(孔隙的大小、形状、相互连接及微观结构的不同)的模型来解释.     

Effect of Water Hardness on the Taste of Alkaline Electrolyzed Water

ABSTRACT: The effect of water hardness on the taste of alkaline electrolyzed water (AEW) was examined by sensory evaluation. Sensory test 1 of commercial bottled mineral water to which calcium and/or magnesium salts had been added was performed by panelists who evaluated the effect of hardness on the taste of water using a scoring method (hedonic scaling test) and a 1-pair comparison method. The water, in which the calcium concentration and the magnesium concentration was 20 mg/L and 2 mg/L, respectively, was found to taste better than any water containing other concentrations of calcium and magnesium. Sensory test 2 of bottled mineral waters having hardnesses of 30 mg/L to 290 mg/L, of activated carbon filtration water having a hardness of 50 mg/L, and of AEWs was performed by panelists using a scoring method (hedonic scaling test) and a pair test, and their preferences for the taste of AEWs was surveyed. The taste of AEW made by electrolyzing activated carbon filtration water did not differ from that of the water before it was electrolyzed. The same was true of AEW made by electrolyzing bottled mineral water having a hardness of 80 mg/L. However, 3 kinds of AEWs made by electrolyzing bottled mineral waters having hardnesses of 30 mg/L, 170 mg/L, and 290 mg/L were found to taste less pleasant than each bottled mineral water before being electrolyzed. The results of sensory tests 1 and 2 show that good-tasting AEW could be produced by an alkaline water electrolyzed from most tap water of Japan because its hardness varies from approximately 50 mg/L to 80 mg/L.