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991.
辣根过氧化物酶在表面活性剂膜中的直接电化学 总被引:14,自引:0,他引:14
利用3种表面活性剂分别将辣根过氧化氢酶固定在裂解石墨棱面(edge-plane pyrolytic graphite,EPG)电极表面,研究了辣根过氧化物酶(HRP)中Fe(Ⅲ)/Fe(Ⅱ)电对与电极之间的直接电子传递过程以及酶催化双氧化还原过程。实验结果表明:(1)表面活性剂是一种固定酶的理想材料;(2)这种体系可能构造第三代生物传感器,对解释生物体代谢过程具有理论意义,对制备第三代生物传感器具有应用价值。 相似文献
992.
Gabriel J. Summers M. Patrick Ndawuni Carol A. Summers 《Journal of polymer science. Part A, Polymer chemistry》2001,39(12):2058-2067
The quantitative synthesis of tertiary amine-functionalized polymers by atom transfer radical polymerization is reported. Tertiary amine-functionalized polystyrene was prepared with the adduct of 1-(bromoethyl)benzene with 1-(4-dimethyl-aminophenyl)-1-phenylethylene as an initiator in the atom transfer radical polymerization of styrene in the presence of a copper (I) bromide/2,2′-bipyridyl catalyst system. The polymerization proceeded via a controlled free-radical polymerization process to afford quantitative yields of the corresponding tertiary amine-functionalized polystyrene with predictable number-average molecular weights (1600–4400), narrow molecular weight distributions (1.09–1.31), and an initiator efficiency of 0.95. The polymerization process was monitored by gas chromatographic analysis. The tertiary amine-functionalized polymers were characterized by thin-layer chromatography, size exclusion chromatography, potentiometry, and spectroscopy. All experimental evidence was consistent with quantitative functionalization via the 1,1-diphenylethylene derivative. Polymerization kinetic measurements showed that the polymerization reaction followed first-order-rate kinetics with respect to monomer consumption and that the number-average molecular weight increased linearly with monomer conversion. © 2001 John Wiley & Sons, Inc. J Polym Sci A Part A: Polym Chem 39: 2058–2067, 2001 相似文献
993.
994.
995.
YI Xiao-Jie NIE Yi-You ZHOU Nan-Run HUANG Yi-Bing HONG Zhi-Hui LI Song-Song 《理论物理通讯》2008,50(1):81-84
We present a scheme for quantum secure direct communication, in which the message is encoded by local unitary operations, transmitted through entangled photons, and deduced from both the sender and receiver's local measurement results. In such a scheme, only one pair of entangled photons is consumed, and there is no need to transmit the sender's qubit carrying the secret message in a public channel, in order to transmit two-bit classical information. 相似文献
996.
A quantum secure direct intercommunication scheme is
proposed to exchange directly the communicators' secret messages by
making use of swapping entanglement of Bell states. It has great
capacity to distribute the secret messages since these messages have
been imposed on high-dimensional Bell states via the local unitary
operations with superdense coding. The security is ensured by the
secure transmission of the travel sequences and the application of
entanglement swapping. 相似文献
997.
低Pr数流体自然对流边界层流动的直接数值模拟 总被引:1,自引:0,他引:1
在太阳能采暖通风系统中,空气在太阳辐射作用下于吸热壁上所形成的非稳态自然对流边界
层流动是决定系统热性能的关键所在. 对于线性分层的低普郎特数($Pr<1$)流体而言,标度分
析表明在起始阶段边界层的发展是与高度无关而只依赖于时间的,而处于稳态时,各项标度
关系与处于起始阶段终结时刻的大不相同,且都与高度和时间无关,而只与$Pr$数和线性分
层度相关. 直接数值模拟计算结果表明由标度分析所得的各项标度关系揭示了流动的特性参
数与控制参数之间的决定性内在联系. 但同时也表明标度关系并没有充分体现出
对$Pr$数的所有依赖关系,这一不足可利用直接数值模拟计算结果得到弥补. 相似文献
998.
动态存储方法在气相爆轰波数值模拟中的应用 总被引:1,自引:0,他引:1
为减少反应流计算花费的时间,采用动态存储建立热力学数据表(In situ adaptive tabulation, ISAT)的方法来取代反应流计算中化学反应的直接积分(Direct integral, DI),并针对气相H2/O2爆轰波的传播过程进行了数值模拟。采用两种不同的ISAT误差放大判据对一维爆轰波的压力、温度及组分变化进行了计算,并和DI的结果进行了比较以考察其计算精度。此外,还探讨了ISAT方法的效率。计算结果表明,和DI方法相比,在爆轰波传播计算中ISAT方法计算误差小于3%,化学反应计算速度提高了8倍。 相似文献
999.
Kanhaiya L. Yadav Amarjeet K. Narula Ramadhar Singh Subhas Chandra 《Applied biochemistry and biotechnology》2001,96(1-3):119-124
The direct current (dc) conductivity of poly(3-methyl thiophene) was measured in the temperature range of 77–300 K. The observed dc conductivity data were analyzed in the light of Mott’s variable range hopping model. Different Mott’s parameters such as
characteristic temperature (T
0), average hopping distance (R), average hopping energy (W), and density of states at the Fermi level (N [E
F
]) were evaluated. By taking the inverse of the coefficient of exponential decay of the localized states involved in the hopping
process as 0.5 nm, a realistic value of density of states at the Fermi level (N [E
F
]) was obtained that agrees well with the values reported earlier for other conjugated polymers. 相似文献
1000.
Summary: SPTES polymers have been successfully synthesized by direct polymerization using tetramethylene sulfone as the solvent. The chemical structures of the SPTES polymers are confirmed by FT‐IR and NMR spectroscopy. The thermal stability is characterized by TGA, and the results show that the sulfonated groups on the polymer backbone are stable up to 300 °C. The measured proton conductivity reaches values above 300 mS · cm−1 at 65 °C and 85% relative humidity. Tough, ductile, free‐standing membranes have been fabricated by solution casting from N,N‐dimethylacetamide, which indicates that the SPTES polymers have excellent membrane‐forming capability and mechanical property. The mono‐functional monomers are introduced into the polymerization to end‐cap the SPTES polymers. The end‐capping groups are effective in improving water resistance, oxidative stability, and retaining the proton conductivity.