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131.
GOU Xiao-jun YIN Shao-man KONG Xiang-duo ZHU Shi-zhen WANG Xiao-ping ZHANG Hong-ying ZHANG Jin Key Laboratory for Molecular Enzymology Engineering of Ministry of Education Jilin University Changchun P. R. ChinaZHU HongThe Jilin Provi 《高等学校化学研究》2002,18(1):20-24
IntroductionCopper,zinc- superoxide dismutases(SODs;EC.1.15 .1.1) are essential plasmic enzymes which cat-alyze the dismutation of highly reactive superoxideradical anions to hydrogen peroxide and oxygen so thatthe generation and clearance of oxygen free radicalsare regulated[1— 3 ] . The studies show that oxygen freeradicals play important roles in aging and the regula-tion of nitrogen monoxide[4,5] .The failure of the prop-er regulation will lead to inflammation,ischemicreperfusion injury… 相似文献
132.
Metal ion exchanged montmorillonites (AlM & CrM) and metal oxide pillared montmorillonite (AlPM & CrPM) were prepared and characterized with XRD, FT‐IR, nitrogen adsorption and TPD of ammonia. The pillaring process results in a remarkable increase of interlayer distance, surface area and acid amount of the catalyst. However, increasing the calcined temperature causes reverse effects for the CrPM catalyst. The acid amount decreases in the order of CrPM200 < CrPM300 < AlPM500 < CrM < CrPM400 ≥ CrPM500 ≥ AlM. In the dehydration of 2‐propanol to propene, the reaction follows first order kinetics and the apparent rate constant is related to the catalyst acid amount. Compensation effect occurs in this reaction over the series of catalysts. 相似文献
133.
Study of total ionizing dose radiation effects on enclosed gate transistors in a commercial CMOS technology
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This paper studies the total ionizing dose radiation effects on MOS
(metal-oxide-semiconductor) transistors with normal and enclosed gate
layout in a standard commercial CMOS (compensate MOS) bulk process.
The leakage current, threshold voltage shift, and transconductance of
the devices were monitored before and after $\gamma $-ray
irradiation. The parameters of the devices with different layout
under different bias condition during irradiation at different total
dose are investigated. The results show that the enclosed layout not
only effectively eliminates the leakage but also improves the
performance of threshold voltage and transconductance for NMOS
(n-type channel MOS) transistors. The experimental results also
indicate that analogue bias during irradiation is the worst case for
enclosed gate NMOS. There is no evident different behaviour observed
between normal PMOS (p-type channel MOS) transistors and enclosed
gate PMOS transistors. 相似文献
134.
In this paper a relativistic many-body perturbation calculation is
performed to calculate the hyperfine constants of the ground states
for lithium-like isoelectronic sequence. Zeroth-order hyperfine
constants are calculated with Dirac--Fock wavefunctions, and the
finite basis sets of the Dirac--Fock equations are constructed by B
splines. With the finite basis sets, the core polarization and the
correlation effect are evaluated. 相似文献
135.
GOUXiao-jun ZHANGZhong-hua LIShuang KONGXiang-duo SUNYan-hong LIUWei ZHAGNJin 《高等学校化学研究》2004,20(1):55-59
Human extracellular superoxide dismutase(hEC-SOD) is a secreted tetrameric protein involved in the protection of a human body from oxygen free radicals. Its three-dimensional structure has not been confirmed, hEC-SOD couldn′t be expressed in E.coll. We constructed a hybrid enzyme, which comprises the Nterminal and C-terminal domains from hEC-SOD, fused it to human Cu, Zn-SOD. The hybrid enzyme is expressed successfully in E. coli. Further, we analyzed the expression of hEC-SOD in E. coli by mRNA differential displaying. 相似文献
136.
新反应、新试剂的发展是有机合成化学的重要研究内容,基于前期在α-氨基丙二腈合成方法学方面的工作基础,我们发展了一例铜催化的α-氨基丙二腈的脱氰氧代反应.通过将甲酰胺转化为α-氨基丙二腈后,借助其亲核属性来合成α-氨基丙二腈底物,而后将底物重新转化为酰胺,从而实现形式上的氨基甲酰负离子的亲核加成(取代)反应.该工作首次完成了形式上的甲酰胺碳原子的极性反转,实现了将α-氨基丙二腈作为氨基甲酰负离子替代物的反应新模式,为叔酰胺化合物的合成提供了新的思路和方法,且具有反应条件简单,底物适用性广及适合克级规模制备等特点. 相似文献
137.
Rui Li Xin Gou Xinyan Li Hainuo Wang Haibo Ruan Yuting Xiong Xianlun Tang Yuanyuan Li Ping-an Yang 《Molecules (Basel, Switzerland)》2022,27(15)
Flexible strain sensors, when considering high sensitivity and a large strain range, have become a key requirement for current robotic applications. However, it is still a thorny issue to take both factors into consideration at the same time. Here, we report a sandwich-structured strain sensor based on Fe nanowires (Fe NWs) that has a high GF (37–53) while taking into account a large strain range (15–57.5%), low hysteresis (2.45%), stability, and low cost with an areal density of Fe NWs of 4.4 mg/cm2. Additionally, the relationship between the contact point of the conductive network, the output resistance, and the areal density of the sensing unit is analyzed. Microscopically, the contact points of the conductive network directly affect the sensor output resistance distribution, thereby affecting the gauge factor (GF) of the sensor. Macroscopically, the areal density and the output resistivity of the strain sensor have the opposite percolation theory, which affects its linearity performance. At the same time, there is a positive correlation between the areal density and the contact point: when the stretching amount is constant, it theoretically shows that the areal density affects the GF. When the areal density reaches this percolation threshold range, the sensing performance is the best. This will lay the foundation for rapid applications in wearable robots. 相似文献
138.
139.
140.
Bo-Sheng Zhang Ying-Hui Yang Fan Wang Xue-Ya Gou Xi-Cun Wang Yong-Min Liang Yuke Li Zheng-Jun Quan 《中国化学》2021,(6):1573-1579
Main observation and conclusion
This paper describes the first case of a reductive coupling reaction with indene,a non-heteroatom olefin used as a reducing agen... 相似文献