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Improvement of xylanase production by Aspergillus niger XY-1 using response surface methodology for optimizing the medium composition

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第7期9卷 558-566页

作者： Yao-xing xu Yan-li li Shao-chun xu Yong liU Xin WANG Jiang-wu TANG Institute of Plant Protection and Microbiology Zhejiang Academy of Agricultural Sciences Hangzhou 310021 China

Objective: To study the optimal medium composition for xylanase production by Aspergillus niger XY-1 in solid-state fermentation (SSF). Methods: Statistical methodology including the Plackett-Burman design (PBD) and the central composite design (CCD) was employed to investigate the individual crucial component of the medium that significantly affected the enzyme yield. Results: Firstly, NaNO3, yeast extract, urea, Na2CO3, MgSO4, peptone and (NH4)2SO4 were screened as the significant factors positively affecting the xylanase production by PBD. Secondly, by valuating the nitrogen sources effect, urea was proved to be the most effective and economic nitrogen source for xylanase production and used for further optimization. Finally, the CCD and response surface methodology (RSM) were applied to determine the optimal concentration of each sig-nificant variable, which included urea, Na2CO3 and MgSO4. Subsequently a second-order polynomial was determined by multiple regression analysis. The optimum values of the critical components for maximum xylanase production were obtained as follows: x1 (urea)=0.163 (41.63 g/L), x2 (Na2CO3)=?1.68 (2.64 g/L), x3 (MgSO4)=1.338 (10.68 g/L) and the predicted xylanase value was 14374.6 U/g dry substrate. Using the optimized condition, xylanase production by Aspergillus niger XY-1 after 48 h fermentation reached 14637 U/g dry substrate with wheat bran in the shake flask. Conclusion: By using PBD and CCD, we obtained the optimal composition for xylanase production by Aspergillus niger XY-1 in SSF, and the results of no additional expensive medium and shortened fermentation time for higher xylanase production show the potential for industrial utilization.

关键词： Xylanase Optimization of medium composition Plackett-Burman design (PBD) Central composite design (CCD) Response surface methodology (RSM). Aspergillus niger XY- 1

Syntheses,Structure and Biological Activities of 2-(1H-Benzo [1,2,3]triazole-1-yl)-1-(3-methyl-4-bromobiphenyl)-2-(1H-1,2,4-triazole-1-yl)ethanone

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Chemical Research in Chinese Universities 2007年第1期23卷 120-122页

作者： ZHANG Shu-sheng WAN Jun li xue-mei li chun-li xu liang-zhong College of Chemistry and Molecular Engineering Qingdao University of Science and Technology Qingdao 266042 P. R. China

1,2,4-Triazole derivatives represent an interesting class of heterocyclic compounds and have become the most with rapidly expanding group of antifungal compounds the advantages of toxicity, high oral bioavailability, and broad spectrum of activity against several fun- gi, including most yeasts and folanentous fungi . The triazole fungicides are agrochemicals that are used world wide in the agricultural industry because of their wide spectrum of action, A variety of benzotriazoles exhibit growth-inhibiting activities against some microorganisms and other derivatives possessing anti-inflammatory properties.

关键词： Triazole derivative Cyrstal structure Biological activity

SmI_2-promoted imino-Reformatsky reaction for facile synthesis of enantioenriched β-amino acid esters

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Science China Chemistry 2011年第1期54卷 61-65页

作者： WANG li SHEN chun xu Ming-Hua Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai 201203 China

A facile and efficient method for the stereoselective synthesis of β-amino acid esters via SmI2-promoted imino-Reformatsky reaction is *** addition of tert-butyl bromoacetate to N-tert-butanesulfinyl aldimines afforded β-amino acid esters in moderate to high yields with excellent *** synthetic utilities of the tert-butyl β-amino acid esters were expanded by the preparation of β-lactams and 3-aminoindan-1-ones derivatives.

关键词： β-amino acid ester samarium diiodide N-tert-butanesulfinyl imine Reformatsky reaction β-lactam 3-aminoindan-1-one asymmetric synthesis

Polar, catalytic, and conductive CoSe2/C frameworks for performance enhanced S cathode in li–S batteries

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Journal of Energy Chemistry 2020年第9期29卷 128-135,I0004页

作者： Bo Yuan Di Hua Xingxing Gu Yu Shen li-chun xu Xiuyan li Bing Zheng Jiansheng Wu Weina Zhang Sheng li Fengwei Huo Key Laboratory of Flexible Electronics(KLOFE) Institute of Advanced Materials(IAM)Nanjing Tech UniversityNanjing 211816JiangsuChina Chongqing Key Laboratory of Catalysis and New Environmental Materials College of Environment and ResourcesChongqing Technology and Business UniversityChongqing 400067China College of Physics and Optoelectronics Taiyuan University of TechnologyTaiyuan 030024ShanxiChina

lithium-sulfur battery(li-S)is considered as one of the new-generation rechargeable batteries with high performance because of its extremely high theoretical capacity,energy density,environmental harmony and low ***,low electrical and ionic conductivity of sulfur,safety concerns and parasitic reaction generated by the dissolved polysulfide species in electrolyte hinder the commercialization of li-S ***,we report a polyhedral porous structure comprising of carbon coating metal selenide nanoparticles(CoSe2/C),which could not only host sulfur for li-S battery owing to its porous and conductive structure,but also mitigate the shuttle phenomenon by polysulfides adsorption and catalytic acceleration of redox *** a result,a performance enhanced CoSe2/C-S electrode for li-S battery is achieved.

关键词： Catalytic Polar Conductive Sulfur cathode Cobalt Selenides

Lateral growth rate of δ phase during solidification of Fe-0.15wt%C-0.8wt%Mn steel

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International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 312-316页

作者： Guo-wei Chang Shu-ying Chen Qing-chun li xu-dong Yue Guang-can Jin School of Materials Science and Engineering Liaoning University of Technology Jinzhou 121001 China

Taking Fe-0.15wt%C-0.8wt%Mn steel as the research object, in situ observations of the 8 phase growth process during solidifica- tion were conducted by using a high-temperature confocal scanning laser microscope （HTCSLM）. The effects of the solid/liquid （S/L） inter- face＇s shape, temperature, and curvature radius on the lateral growth rate of 6 phase were investigated in detail, and the relational expression among the lateral growth rate of 5 phase, temperature, and curvature radius of column-shaped ~ phase was deduced for the carbon steel dur- ing solidificatiorL The results indicate the growth rate of the concave-shaped S/L interface is larger than that of the convex-shaped S/L inter- face during the beginning growth of ~ phase, but these two kinds of growth rates gradually approach with proceeding in solidification. The calculated lateral growth rate of 6 phase is consistent with the experimental result at a cooling rate of 0.045℃/s.

关键词： carbon steel solidification ferrite growth rate interfaces

TiS_(2)-graphene heterostructures enabling polysulfide anchoring and fast electrocatalyst for lithium-sulfur batteries:A first-principles calculation

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Chinese Physics B 2022年第4期31卷 574-582页

作者： Wenyang Zhao li-chun xu Yuhong Guo Zhi Yang Ruiping liu Xiuyan li College of Physics and Optoelectronics Taiyuan University of TechnologyTaiyuan 030024China

lithium-sulfur batteries have attracted attention because of their high energy ***,the "shuttle effect" caused by the dissolving of polysulfide in the electrolyte has greatly hindered the widespread commercial use of lithiumsulfur *** this paper,a novel two-dimensional TiS2/graphene heterostructure is theoretically designed as the anchoring material for lithium-sulfur batteries to suppress the shuttle *** heterostructure formed by the stacking of graphene and TiS2 monolayer is the van der Waals type,which retains the intrinsic metallic electronic structure of graphene and TiS2 *** improves the electronic conductivity of the sulfur cathode,and the transferred electrons from graphene enhance the polarity of the TiS2 *** of the polysulfide adsorption show that the TiS2/graphene hetero structure can maintain good metallic properties and the appropriate adsorption energies of 0.98-3.72 eV,which can effectively anchor *** transfer analysis suggests that further enhancement of polarity is beneficial to reduce the high proportion of van der Waals(vdW) force in the adsorption energy,thereby further enhancing the anchoring *** li2 S decomposition barrier and li-ion migration barrier imply that the heterostructure has the ability to catalyze fast electrochemical kinetic ***,TiS2/graphene heterostructure could be an important candidate for ideal anchoring materials of lithium-sulfur batteries.

关键词： lithium-sulfur batteries TiS_(2)/graphene heterostructure anchoring material shuttle effect

Lateral Growth Rate of Cells in Melt

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Journal of Iron and Steel Research International 2012年第4期19卷 28-33,50页

作者： CHANG Guo-wei CHEN Shu-ying li Qing-chun YUE xu-dong JIN Guang-can School of Materials Science and Engineering Liaoning University of Technology J inzhou 121001 Liaoning China

Growth process of δ-phase was studied during the solidification of carbon *** analyzing the solute diffusion around cylindrical crystals in the melt,the mathematic representation of lateral growth rate of cylindrical crystals was confirmed;the calculation and analysis of lateral growth rate were carried *** order to validate the theoretical calculation and analysis,the growth process of δ-phase during the solidification was in-situ observed using a confocal scaning laser microscope（CSLM） and the growth rates were measured through CSLM *** results show that lateral growth rates of δ-phase in the carbon steel first rapidly decrease with the increase of the radius of the cylindrical crystal,and then slowly fall down or maintain *** radius of δ-phase is the primary factor to affect the growth *** higher the temperature gradient is,the bigger the growth rate ***,the effect of the temperature gradient is *** correlation is obtained between theoretical analysis and experiment results in absolute values of lateral growth rate and change rule

关键词： cell growth solidification process carbon steel in-situ observation

Facile synthesis of 9-(N-amino-4-fluoromethyl-3-pyrrolidinyl)-2-fluoro-6-aminopurine from trans-4-hydroxy-L-proline

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Chinese Chemical Letters 2007年第11期18卷 1313-1315页

作者： Ye Qing li Ming Lu chun xu Lu Sai Jian Zhu Qi Fa liu Chemical Engineering College Nanjing University of Science and Technology Nanjing 210094 PR China

A novel and simple procedure for synthesis of azanucleoside by Mitsunobu reaction between N-（p-nitrobenzyloxycarbonyl）- trans-4-hydroxy-D-proline methyl ester obtained from trans-4-hydroxy-L-proline after six-step reaction and 2-fluoro-6-azidopurine is described, and azanucleoside is fluorinated by new fluridizer 2,2-difluoro-1,3-dimethylimidazolidine （DFI）. All reactions could be carried out under mild condition.

关键词： trans-4-Hydroxy-D-proline 2-Fluoro-6-azidopurine Fluoride azanucleosides Mitsunobu reaction DFI

Variations in Reproductive Hormones during Estrus Cycle in Local Beef Cattle from Jilin of China

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Animal Husbandry and Feed Science 2010年第4期2卷 14-17页

作者： li Cheng-jiao WANG Hong-juan li chun-jin ZHOU xu College of Animal Science and Veterinary Medicine Jilin University Changchun 130062 China

[ Objective] To provide a theoretical basis for improving reproductive efficiency of domestic beef cattle in Jilin of China. [ Method] China Red Steppe cattle, Yanbian yellow cattle and Simmental cattle in Jilin Province were used for detection. The levels of progesterone （P4）, estradiol （ E2 ）, follicle-stimulating hormone （FSH） and luteinizing hormone （LH） in serum and urine during estrus cycle were determined. [ Result] The levels of P4 and E2 were significantly different between pregnant cattle and non-pregnant cattle on Day 21 post estrus （ P 〈 0.01 ）. The level of LH on estrus day was significantly different from that on the other days of estrus cycle （ P 〈 0.05）. [ Conclusion] It is feasible to detect P4 level for diagnosis of estrus and eady pregnancy in beef cattle.

关键词： Reproductive hormones Estrus cycle Beef cattle