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Partial Pole Assignment via Constant Gain Feedback in Two Classes of Frequency-domain Models
Guo-Sheng Wang,Guo-Zhen Yang,Guang-Ren Duan 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.2
The design problem of partial pole assignment (PPA) in two classes of frequency-domain MIMO models by constant gain feedback is investigated in this paper. Its aim is to design a constant gain feedback which changes only a subset of the open-loop eigenvalues, while the rest of them are kept unchanged in the closed-loop system. A near general parametric expression for the feedback gain matrix in term of a set of design parameter vectors and the set of the closed-loop poles, and a simple parametric approach for solving the proposed problem are presented. The set of poles do not need to be previously prescribed, and can be set undetermined and treated together with the set of parametric vectors as degrees of design freedom provided by the approach. An illustrative example shows that the proposed parametric method is simple and effective.
Zhou, Guo-Wei,Guo, Guo-Cong,Liu, Bin,Wang, Ming-Sheng,Cai, Li-Zhen,Huang, Jin-Shun Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.5
Complexes M($C_7H_2NO_5)3H_2O{\cdot}H_2O{\cdot}0.25MeCN$ (M=Ni, Co) were crystallized from the reactions of $Ni(CH_3COO)_2{\cdot}4H_2O\;or\;Co(CH_3COO)_2{\cdot}2H_2O$ with KSCN and 2,6-dicarboxy-4-hydroxypyridine (chelidamic acid). The structures were characterized by X-ray crystallography. The crystal structures of 1 and 2 show a distorted octahedral coordination geometry around the M(II) ions, which are chelated by one nitrogen atom and two oxygen atoms of the chelidamic acid and three water molecules. Complexes 1 and 2 display the hydrogen-bonded 3D framework. The magnetic behavior of 2 exhibits antiferromagnetic interaction.
Effect of Molar Ratios on Compressive Strength of Modified Magnesium Oxysulfate Cement
Zhen-guo Li,Ze-sheng Ji 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6
To determine the effect of molar ratios on compressive strength of magnesium oxysulfate cement (MOS), the hardened MOS cement pastes mixed with different molar ratios of MgO/MgSO4 and H2O/MgSO4 were tested on the compressive strength. The examinations of strength development, phase compositions and microstructure of MOS cement are discussed in detail. The results show that these starting materials can significantly affect the compressive strength of MOS cement. The mixture with higher molar ratio of MgO/MgSO4 and lower molar ratio of H2O/MgSO4 can produce more 5Mg(OH)2 ·MgSO4·7H2O(517 phase) and less Mg(OH)2, which benefits the compressive strength of MOS cement.
Directed Evolution of Beta-galactosidase from Escherichia coli into Beta-glucuronidase
Xiong, Ai-Sheng,Peng, Ri-He,Zhuang, Jing,Liu, Jin-Ge,Xu, Fang,Cai, Bin,Guo, Zhao-Kui,Qiao, Yu-Shan,Chen, Jian-Min,Zhang, Zhen,Yao, Quan-Hong Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.3
In vitro directed evolution through DNA shuffling is a powerful molecular tool for creation of new biological phenotypes. E. coli $\beta$-galactosidase and $\beta$-glucuronidase are widely used, and their biological function, catalytic mechanism, and molecular structures are well characterized. We applied an in vitro directed evolution strategy through DNA shuffling and obtained five mutants named YG6764, YG6768, YG6769, YG6770 and YG6771 after two rounds of DNA shuffling and screening, which exhibited more $\beta$-glucuronidase activity than wild-type $\beta$-galactosidase. These variants had mutations at fourteen nucleic acid sites, resulting in changes in ten amino acids: S193N, T266A, Q267R, V411A, D448G, G466A, L527I, M543I, Q626R and Q951R. We expressed and purified those mutant proteins. Compared to the wild-type protein, five mutant proteins exhibited high $\beta$-glucuronidase activity. The comparison of molecular models of the mutated and wildtype enzymes revealed the relationship between protein function and structural modification.