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RISS 인기검색어
- 검색키워드
- 저자 : Cheng-Gen Zhang (검색결과 6 건)
- 무료
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Yu, Shu-Yuan,Zhang, Cheng-Gen,Wang, Shu-Jun Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.5
The multiconfiguration second-order perturbation theory (CASPT2) and complete active space self-consistent field (CASSCF) methods were employed to calculate the geometries and energy levels for the low-lying electronic states of 1,3,5-$C_6H_3Cl{_3}^+$ ion. The CASPT2 values for the 1,3,5-$C_6H_3Cl{_3}^+$ ion were in reasonable agreement with the available experimental values. The current calculations augmented previous theoretical investigations on the ground state and assigned the low-lying excited electronic states of the 1,3,5-$C_6H_3Cl{_3}^+$ ion. The Jahn-Teller distortion in the excited electronic state for the 1,3,5-$C_6H_3Cl{_3}^+$ ion were reported for the first time.
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CASPT2 Study on the Low-lying Electronic States of 1,3,5-C6H3Cl3 + Ion
Shu-Yuan Yu,Cheng-Gen Zhang,Shu-Jun Wang 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.5
The multiconfiguration second-order perturbation theory (CASPT2) and complete active space self-consistent field (CASSCF) methods were employed to calculate the geometries and energy levels for the low-lying electronic states of 1,3,5-C6H3Cl3 + ion. The CASPT2 values for the 1,3,5-C6H3Cl3 + ion were in reasonable agreement with the available experimental values. The current calculations augmented previous theoretical investigations on the ground state and assigned the low-lying excited electronic states of the 1,3,5-C6H3Cl3 + ion. The Jahn-Teller distortion in the excited electronic state for the 1,3,5-C6H3Cl3 + ion were reported for the first time.
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Shu-Jun Wang,Yu-Ling Peng,Cheng-Gen Zhang,Yong-Bing Li,Chao Liu 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.11
Three metal-free porphyrins modified with Boc-l-threonine and their zinc analogs were synthesized and characterized by elemental analysis,1H NMR, UV/vis, and fluorescence spectroscopies. The binding of imidazole derivatives to these zinc porphyrins was studied, with emphasis on the binding mechanism in CH2Cl2 solution, by means of UV/vis spectroscopy and quantum chemical methods. Both experimental results and theoretical calculations showed that a coordination reaction occurred between the zinc porphyrins and imidazole derivatives. The association constants between the zinc porphyrins and imidazole derivatives decreased in the order N-MeIm>Im. Increasing the temperature disfavored the interaction. Thermodynamic parameters calculated by the van't Hoff equation showed that the driving force for the reaction was the enthalpy change. The fluorescence changes associated with the interaction between the zinc porphyrins and imidazole derivatives were also studied by fluorescence spectroscopy. The experimental results showed significant quenching between the various zinc porphyrins and imidazole derivatives.
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Shu-Jun Wang,Yu-Ling Peng,Cheng-Gen Zhang,Qi Peng Ma,Xiao Xia Peng,Li Lei Ren 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.7
Two kinds of free-base tailed porphyrins modified with 2-chloronicotinic acid and the corresponding Zn porphyrins have been synthesized. They have been characterized by elemental analysis and NMR, UV/Vis, fluorescence spectra, and infrared spectroscopies. Their configurations have been optimized through theoretical calculations. The fluorescence quantum yields were determined by a comparative method. The interactions between the Zn porphyrins and human serum albumin have been studied by means of fluorescence spectra. The experimental results showed that the interaction mechanism involved a combined fluorescence quenching process (static and dynamic quenching) and that the main driving force was hydrophobic in nature. Quenching constants, binding constants, thermodynamic parameters, and binding distances have been determined.
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Thermo-Mechanical Behavior of Long-Bored Energy Pile: A Full-Scale Field Investigation
Gang Jiang,Dong Shao,Chenfeng Zong,Gen Chen,Jie Huang,Cheng Lin,Xudong Wang,Yuwei Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1
A geothermal energy pile is a revolutionary piling technique that combines a pile foundation with a ground source heat pump system that not only supports the structure but also provides heating and cooling for buildings and bridges. The thermo-mechanical behavior of long energy piles in soft clay has rarely been investigated, despite their increasing utilization. A long floating energy pile with a length-to-diameter ratio of 66.7 was evaluated on its own and monitored in service of the supported structure in the city of Kunshan, China. With vertical mechanical loads, the experiment involved alternate cooling and heating cycles, allowing for careful analysis and assessment of the pile's temperature, stress, and displacement. Temperature-induced stress, axial force, and friction resistance of the pile shaft, as well as the change in displacement of the energy pile throughout building, were all studied. The field observations revealed without any surprise that a longer energy pile outperformed a shorter one in terms of heating exchange capacity with a more homogenous temperature distribution along the pile. Following a quasi-linear relationship with the temperature variation, the thermo-induced additional axial force soared with the larger length-diameter ratio of the pile and may even reach four times that of the pile under pure mechanical loads. Important additional settlements were also observed especially in cooling conditions. The shaft frictions along the long bored energy pile were found to have a complicated distribution, which requires further investigations.
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Shu-Yuan Yu,Ping Ren,Hui-Min Zheng,Cheng-Gen Zhang 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.3
Copolymerization mechanisms of norbornadiene (NBD) and propylene, catalyzed by three zirconocene catalysts (namely, rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2/MAO (catA), rac-Me2Si(Ind)2ZrCl2/MAO (catB), and rac-CH2CH2(Ind)2ZrCl2/MAO(catC)), have been studied, using density functional theory computations. It has been found that the barrier (28.5 kcal mol−1) for the insertion of propylene to the [Zr]A-NBD-PP1 (the NBD insertion product) is significantly higher than those to [Zr]B-NBD-PP1 (22.9 kcal mol−1) and [Zr]C-NBD-PP1 (20.5 kcal mol−1), rationalizing the experimental observation that addition of NBD deactivated catA system but only lowered the catalytic activity of catB and catC systems. However, [Zr]A-NBD-PP1 can react with H2 easily, which displaces NBD−PP1 chain and gives active [Zr]A−H species to continue copolymerization, which is why the introduction of H2 could recover the catalytic activity of catA system.
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