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971.
α,β-Unsaturated trifluoromethylketones of cyclobutene number containing trimethylstannyl substituent in β-position were firstly prepared by the addition of trimethylstannyllithium to the corresponding trifluoromethylenaminoketones. The protection of carbonyl function under basic conditions conserving the organometallic substituent was elaborated. The generation of corresponding organolithiums by Sn-Li exchange and their reactivity was studied. 相似文献
972.
Coherent control of OH‐free radicals interacting with the spin‐triplet state of a DNA molecule is investigated. A model Hamiltonian for molecular spin singlet‐triplet resonance is developed. We illustrate that the spin‐triplet state in DNA molecules can be efficiently populated, as the spin‐injection rate can be tuned to be orders of magnitudes greater than the decay rate due to small spin‐orbit coupling in organic molecules. Owing to the nano‐second life‐time of OH free radicals, a non‐equilibrium free energy barrier induced by the injected spin triplet state that lasts approximately longer than one‐micro second in room temperature can efficiently block the initial Hydrogen abstraction and DNA damage. For a direct demonstration of the spin‐blockade effect, a molecular simulation based on an ab‐initio Car‐Parrinello molecular dynamics is deployed. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010 相似文献
973.
974.
A.A. Al-Ghamdi Nadia Abdel Aal Waleed E. Mahmoud 《Polymer Degradation and Stability》2009,94(6):980-986
Poly(vinyl Chloride)/graphite nanosheet/nickel (PVC/GN) nancomposites are new alternative candidates for electrostatic charge dissipation and electromagnetic interference shielding applications due to their lightweight, ease processing and tunable conductivities. The structures of the nanocomposites were examined by means of scanning electron microscopy (SEM) and X-ray analysis. The mechanical properties such as hardness, modulus of elasticity and elongation at break as a function of GN content were examined. The applicability of the nanocomposites as electrostatic charge dissipation was tested in terms of displaying the variation of decay voltage with time. In addition, the dielectric properties such as real and imaginary permittivity of composites as functions of frequency were investigated. Finally, the electromagnetic properties were measured in the frequency range from 1 to 12 GHz and compared with theoretical modeling. The highest shielding effectiveness at microwave frequency of these nanocomposites was 47 dB which is realistic for defense applications like radar evasion. 相似文献
975.
976.
Attenuated total reflectance (ATR) spectroscopy was used to perform in situ studies of the corrosion inhibition of cuprous oxide (Cu2O) by benzotriazole (BTA) in aqueous solution at concentrations from 1 to 20 μM. Because two separate processes occur simultaneously, that of Cu2O corrosion and corrosion inhibition by BTA adsorption, the spectral information was subjected to deconvolution by a conjugate gradient minimization algorithm. Under these conditions, a solution phase concentration of 7-10 μM BTA nearly completely inhibited the corrosion of Cu2O in deionized water. Using a Langmuir adsorption model, this represented only 25% of the maximally covered surface area. 相似文献
977.
978.
979.
化学战剂的分析测试进展 总被引:2,自引:0,他引:2
边归国 《分析测试技术与仪器》2004,10(2):87-92
综述了气相色谱、液相色谱、红外光谱、色质联用、生化传感器、核磁共振、军用侦毒设备、分光光度计、毛细管电泳等仪器对化学战剂分析测试的应用进展情况. 相似文献
980.
V.?I.?Pavlenko R.?N.?YastrebinskiiEmail author P.?V.?Matyukhin D.?V.?Voronov 《Russian Physics Journal》2008,51(11):1188-1194
Physical processes of fast electron and gamma-radiation beam interaction with radiation protection ferric oxide composite
materials are investigated together with dependences of energy (flux) accumulation and transmission coefficients on the gamma-radiation
energy and thickness of a protective screen. Integral characteristics of radiation protection materials are calculated.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 66–71, November, 2008. 相似文献