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991.
Jian‐Li Guo Chong Liu Bin‐Bin Xie Yan‐Ying Zhao Ke‐Mei Pei Hui‐Gang Wang Xuming Zheng Yue‐Jie Ai Xue‐Bo Chen Wei‐Hai Fang Chi Shun Yeung 《Journal of Raman spectroscopy : JRS》2012,43(10):1477-1486
The photophysics and photochemistry of pyrazine (C4H4N2, D2h) after excitation to the S2 (1 1B2u, 1ππ*) electronic state were studied by using the resonance Raman spectroscopy and complete active space self‐consistent field method calculations. The B‐band resonance Raman spectra in cyclohexane solvent were obtained at 266.0, 252.7, and 245.9 nm excitation wavelengths to probe the structural dynamics of pyrazine in the S2 (1 1B2u, 1ππ*) state. Three electronic states 1 1B3u, 1 1B1g, and 1 1B2g were found to couple with the S2 (1 1B2u, 1ππ*) state. Two conical intersection (CI) points CI[S2(B2u)/S1(B3u)] and CI[S1/S0] and one transition state of the isomerization between pyrazine and pyrimidine were predicted to play important roles in the photochemistry of pyrazine. On the basis of the calculations, the mechanism of the photoisomerization reaction between pyrazine and pyrimidine has been proposed. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
992.
A novel organocatalytic asymmetric tandem Michael-Henry reaction catalyzed by 9-amino-9-deoxyepiquinine (VI) has been developed. The reaction was efficiently catalyzed by catalyst VI to give highly functionalized cyclohexanes with four stereogenic carbons including two quaternary stereocenters in excellent enantioselectivities (97 to >99% ee) and high diastereoselectivities (93:7-99:1 dr). Thus, the first organocatalytic asymmetric Henry reaction of common ketones as acceptors is shown. 相似文献
993.
Fluorescence resonance energy transfer in conjugated polymer composite materials was exploited for the detection of gamma ray dosage with high sensitivity and response linearity. 相似文献
994.
Phototransformation mechanism of monuron induced by the triplet benzophenone in aqueous solution 下载免费PDF全文
Phototransformation mechanism of monuron induced by the triplet benzophenone in aqueous solution was investigated by laser flash photolysis technique, while quenching of the triplet benzophenone by monuron was studied by nanosecond transient absorption spectroscopy. The transient species in the transient absorption spectra have been identified by quantum chemistry calculations. The results show that under 355‐nm irradiation proton transfer between the triplet benzophenone and monuron happens, and monuron radical is formed and followed by dechlorination degradation reactions. This work indicated that in aqueous solution some dissolved natural organic matters are helpful to degradation of the organic pollutants under the sunlight. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
995.
序Banach空间非混合单调二元算子不动点的存在唯一性及应用 总被引:1,自引:0,他引:1
利用锥理论和Banach压缩映象原理在更一般的条件下建立了序Banach空间中一类非混合单调二元算子不动点的存在唯一性定理,并应用到Banach空间中二阶非线性Volterra型微分-积分方程初值问题,改进并推广了已有的一些结果. 相似文献
996.
997.
非均相催化一步合成碳酸二苯酯的研究Ⅱ. 焙烧温度对催化剂性能影响 总被引:6,自引:0,他引:6
在不同焙烧温度下制备了非均相催化一步合成碳酸二苯酯所需的催化剂载体并用XRD、SEM及TEM技术对催化剂进行了表征,结果发现,载体的主要物相基本相同,皆为La0.3Mn0.5PbO,但当焙烧温度为800℃时,所得载体的粒径及孔容较好。最后通过合成实验对催化剂的催化性能进行了研究,结果发现,载体的焙烧温度为800℃时碳酸二苯酯的收率可达到5.62%,选择性可达到95.7%。此外还就柠檬酸的添加量对催化剂的催化性能的影响进行了初步的探讨。 相似文献
998.
999.
Min?Li Nan?ZhaoEmail author Nan?Chen Chang-hua?Zhu Chang-xing?Pei 《International Journal of Theoretical Physics》2017,56(9):2710-2715
We propose a novel quantum teleportation protocol for certain class of five-qubit state with a seven-qubit cluster state as quantum channel. In our scheme, the sender merely needs to perform a seven-qubit von-Neumann projective measurement, the original state with deterministic probability can be reconstructed by the receiver after a series corresponding unitary transformations. Compared with other schemes proposed before, our scheme has the distinct advantages of requiring fewer quantum channels, possessing higher intrinsic efficiency, and transmitting more quantum information bits. 相似文献
1000.
该文得到中立型线微分方程组d/dt[x(t)-x(t-τ)] A(t)x(t-σ(t))=0全体非平凡解振动充分条件的代数判别准则。 相似文献