Improved domino logic for high speed design

Techniques are introduced to improve the speed of domino logic. With an inverted clock scheme, a serial transistor is removed and capacitances at the output node are reduced in the new structures. HSPICE simulation shows that over 20% performance enhancement is achieved.     

Effect of the absence of lipoxygenase isoenzymes on the storage characteristics of rice grains

Three varieties of paddy rice with and three varieties without lipoxygenase (LOX) isoenzymes were stored at room temperature, in dark conditions for 42 months. Insect damage and viability were investigated during that time. Varieties without LOX-1,2 and their offspring were screened with a rapid method of estimating LOX isoenzymes, and subjected to an accelerated-ageing experiment. The results indicated that in varieties without LOX-1,2, after long storage, rice quality was normal, but for varieties with LOX-1,2, rice quality deteriorated. With increase of storage time, the germination rate of the seed of most varieties decreased greatly except for varieties without LOX-1,2 where there was almost no change in the germination rate. In varieties without LOX-1,2 and their offspring, after an accelerated ageing experiment the germination rate of some varieties changed slowly, but with others, the germination rate changed quickly. This indicated that a definitive factor, which influenced the life of seeds, may be the loss of LOX-1,2. During storage, there was also a significant difference in the degree of insect damage. In varieties without LOX-3 insect damage was lower, but in varieties with LOX-3 insect damage was higher. Therefore, the absence of LOX-3 may be very important in insect resistance in rice grain.     

纳米陶瓷的制备

纳米陶瓷材料可显著降低材料的烧结致密化程度,节约能源;并可改善陶瓷材料的性能,提高其使用可靠性。主要介绍了纳米陶瓷的制备方法,包括纳米陶瓷粉体的制备、成型和烧结。     

集中载荷作用下的套管抗挤能力分析

根据油田套管损坏情况,建立了集中载荷作用下的套管抗挤能力计算模型,利用能量法和曲杆理论,分析研究了承受180°对称分布集中载荷、90°均匀分布集中载荷和120°均匀分布集中载荷下中厚壁套管抗挤能力,得出了理想圆管抗挤强度和套管屈曲临界挤毁压力的计算公式,通过分析比较理论解与有限元解,其最大相对误差不超过1%,得出了套管抵抗局部载荷的能力低于抵抗均布载荷的结论。     

Electrochemical determination of estradiol using a poly(l-serine) film-modified electrode

A thin film of poly(l-serine) was prepared via electropolymerization for the determination of trace levels of estradiol. In pH 5.0 phosphate buffer, l-serine was oxidized during the cyclic potential sweeps between −0.60 and 2.0 V, forming a thin film at the electrode surface. The electrochemical behavior of estradiol was investigated. The oxidation peak potential of estradiol shifts negatively at the poly(l-serine) film-coated glassy carbon electrode (GCE) compared with that at the bare GCE. Otherwise, the oxidation peak current greatly increases at the poly(l-serine) film-modified GCE. These phenomena suggest that the poly(l-serine) film exhibits catalytic activity towards the electrochemical oxidation of estradiol. Based on this, a sensitive, rapid and simple electrochemical method was proposed for the determination of estradiol. The limit of detection is evaluated to be 2.0 × 10⁻⁸ mol L⁻¹. Finally, this method was successfully used to determine estradiol in blood serum.     

Synthesis and structural characterization of methacrylic acid/octadecyl acrylate‐graft‐poly(methylhydrosiloxane) by hydrosilylation

Methylmethacrylate (MMA) and octadecyl acrylate (OA) were grafted to poly(methylhydrosiloxane) (PMHS) by hydrosilylation, respectively, with hexachloroplatinic acid as catalyst, and the former was further hydrolyzed to prepare methacrylic acid (MAA)‐graft‐PMHS under the alkaline condition. Through orthogonal experiment, main factors affecting the graft reaction between OA and PMHS were discussed and arranged in a decreasing order according to their abilities of the effect on the hydrosilylation of OA with PMHS: catalyst dosage, reaction temperature, reaction time, material ratio, and solvent dosage. It was found that the hydrosilylation of OA with PMHS was easier to that of MMA with PMHS. Under optimal conditions, the grafting ratios of MMA with PMHS and OA with PMHS reached about 90 and 95%, respectively. FTIR and ¹H NMR spectra indicated that the hydrosilylation reactions followed the Markovnikov's rule and played a strong preference toward β‐1,2‐addition. The test of contact angle indicated that surface energy of a system was mainly dependent on the polar groups. The surface energy of OA‐graft‐PMHS (35.07 mN/m) was similar to those of PMHS (35.62 mN/m) and polyoctadecyl acrylate (36.57 mN/m), and lower than that of MAA‐graft‐PMHS (43.50 mN/m). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

离心压缩机可倾轴瓦油封漏油问题的解决

本文全面分析了DH80—16型离心压缩机可倾轴瓦油封漏油的原因,并介绍了可倾轴瓦油封漏油问题的解决及具体实施方案。     

热焊弯管用钢板工艺探讨

在统计分析、正交多项式回归和模拟试验的基础上，建立了高精度的屈强比预报模型，并运用多元函数极值原理，求导极值点及相应的工艺参数，为优化工艺制度，提高热焊弯管用钢(L360-WG系列)性能合格率提供了定量依据。     

中国古代金的分析技术

归纳总结了中国古代金分析技术的主要成果和与其相关的重要事件，对于认识金的分析技术的起源有一定的参考意义。