Optimization of Medium Components for Plasmid Production by Recombinant E. coli DH5α pUK21CMVβ1.2

Yinghua Lu,Shuzhen Zheng,Karl Friehs,Ning He,Xu Deng,Qingbiao Li,Zheng He,Chenyun Xu 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.3

In this study we investigated the effects of carbon and nitrogen sources, and the carbon to nitrogen ratio (C:N) of growth medium on the production of plasmid DNA by pUK21CMVβ1.2 harbouring recombinant E. coli. The results indicated that sucrose and casein peptone were the most suitable carbon and nitrogen sources, respectively, for plasmid production, and the plasmid concentration was significantly influenced by the C:N ratio. A Box-Behnken design and surface response methodology were employed to formulate the optimal medium. In the optimized medium, a plasmid concentration of 51.80 mg/L and a plasmid selectivity of 23.49 mg/g were achieved after 24 h of incubation. These values were approximately 3.5 and 1.7 times higher, respectively, than those obtained on the original LB medium.

Some Developments in Limit Analysis Solutions of Structures

Xu, Bingye,Liu, Yinghua,Cen, Zhangzhi 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.3

This paper summarizes some developments in limit analysis solutions of structures based on the results obtained by the authors and their associates and students over the past ten years. Plates are first considered. Shells are then treated, including circular cylindrical shells, conical shells and the combined shells. Some new methods for limit analysis are the next subjects with the emphasis on the weighted residual method (WRM) and some numerical methods. Finally the problem of brittle plastic material which is a more general model of limit analysis is taken into account. As a conclusion, the analytical methods of limit analysis remain of value to complement the numerical approaches which are more effective for complicated structures and loading conditions.

Removal of malachite green in aqueous solution by adsorption on sawdust

Yinghua Song,Sheguang Ding,Shengming Chen,Hui Xu,Ye Mei,Jianmin Ren 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.12

A new adsorbent was synthesized from sawdust, a forest residue, in which methanol was used as a solvent and triethylamine as a modification agent under the following optimum conditions: 25 oC of reaction temperature, 1 : 8.75 of the ratio of sawdust to triethylamine (g :mL) and 1 hour of reaction time. The adsorption capacity of this adsorbent for malachite green was improved by 632.98% in contrast to that of the unmodified sawdust under the same adsorption conditions. Factors affecting the adsorption behavior of this adsorbent for malachite green, such as pH value, adsorption time, temperature and initial dye concentration, were evaluated through experiments in a batch system. The results indicated that the maximum adsorption capacity can be achieved at 5.08 of pH value and adsorption equilibrium can be reached in 6 hours. It was also found that the higher the temperature, the higher the adsorptive capacity would be. The Freundlich isotherm model provides a better description for the adsorption equilibrium when compared with the Langmuir equation in the conditions of the present study. Additionally, to examine the controlling mechanisms of the process, kinetic equations of the mass transfer and chemical reaction, the pseudo-first order model, the pseudo-second order model and the intraparticle diffusion model were used to correlate the experimental data respectively. The adsorption process of malachite green on sawdust tended to be controlled simultaneously by film mass transfer and intra-particle diffusion and it accompanied chemical reactions. It showed that the sawdust modified with triethylamine had good performance for cationic dye and can be used as a biomass adsorbent to treat dyes-containing wastewater with high quality.

Experimental and Analytical Studies of U-Shaped Thin-Walled RC Beams Under Combined Actions of Torsion, Flexure and Shear

Jianchao Xu,Shenggang Chen,Quanquan Guo,Yinghua Ye,Bo Diao,Y. L. Mo 한국콘크리트학회 2018 International Journal of Concrete Structures and M Vol.12 No.3

U-shaped thin-walled concrete bridge beams usually suffer the combined actions of flexure, shear and torsion, but no research about the behavior of U-shaped thin-walled RC beams under combined actions has been reported in literature. Three large specimens of U-shaped thin-walled RC beams were tested under different torque–bending moment ratios (T–M ratios) of 1:5, 1:1 and 1:0 to investigate the mechanical responses such as crack patterns, reinforcement strains, failure modes and ductility. The testing results showed that ductile flexural failures occurred for all three of the U-shaped thin-walled beam specimens, although the combined shear effect of circulatory torque, warping torque and shear force increased as the T–M ratio increased from 1:5 via 1:1 to 1:0, reflected by diagonal cracks and stirrup strains. More specifically, basically symmetrical flexural failure was dominated by the bending moment when the T–M ratio was 1:5; flexural failure of the loaded half of the U-shaped thin-walled section was dominated by the combined action of the bending moment and warping moment, while there were only a few cracks on the other half of the U-shaped section when the T–M ratio was 1:1; and anti-symmetrical flexural failure was dominated by the warping moment when the T–M ratio was 1:0 (pure torsion). A simple method to calculate the ultimate load of such U-shaped thin-walled RC beams under different T–M ratios was suggested, and the calculating results were corresponding well with the experimental results.

Factors influencing entrepreneurial intentions of Chinese secondary school students: an empirical study

Xiaozhou Xu,Hao Ni,Yinghua Ye 서울대학교 교육연구소 2016 Asia Pacific Education Review Vol.17 No.4

The ideal stage to learn about and foster positive attitudes toward entrepreneurship is believed to be during childhood and adolescence. However, most entrepreneurial studies examine college rather than secondary school students (SSS). Based on a modified theory of planned behavior (TPB), this study used stratified cluster sampling and a questionnaire to review current entrepreneurship education in secondary schools. In addition, the effects of entrepreneurship education, personal traits, and demographics on attitude, subjective norm, perceived behavioral control (PBC), and entrepreneurial intentions (EI) on 1018 SSS in China were studied. Differences, correlations, and structural equation modeling analysis indicated the following. (1) Most SSS had never received entrepreneurship education, likely resulting in lowered entrepreneurial intention and perception of entrepreneurial behavioral performance as unrealistically easy. (2) Cognitive bias existed in SSS’s perceptions of entrepreneurship, and entrepreneurial behaviors were regarded as external cause-oriented activities. (3) Gender and entrepreneurial experience of family member also influenced EI and related variables. (4) Entrepreneurship education and personal traits (locus of control and innovativeness) were significantly positive predictors of EI, and (5) their effects on EI were completely mediated by PBC. The findings supported the TPB predictions, and the results offered some implications for entrepreneurship education in Chinese secondary schools: (1) developing entrepreneurial personal traits while eliminating examination-oriented education, (2) enhancing SSS’s entrepreneurial confidence so entrepreneurial behaviors are perceived as easier and more achievable, and (3) constructing systematic entrepreneurship courses to guarantee transition from secondary to higher education.

Valveless Piezoelectric Micropump of Parallel Double Chambers

Li Guo,Weiping Yan,Yinghua Xu,Yiru Chen 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

The driving performance of the piezoelectric actuator was simulated by ANSYS software, and the relationship between structure parameters and center displacement/frequency of piezoelectric actuator were obtained. The nozzle/diffuser pipes’structure parameters were optimized according to the results of ANSYS numerical simulation, and flow characteristic parameters such as flow rate and pressure distribution in the pipe were researched. The chamber was manufactured on glass, and nozzle/diffuser pipes were fabricated on <100> silicon by selective-wet etch using MEMS technology. These two components were glued with piezoelectric actuator together to form micropumps with single chamber and micropumps with parallel double chambers. The flow rates of micropumps in different conditions were measured by test system. Finally, a comparison between the test results of micropump with double chambers and that of the single chamber micropump is given.

Optimization of Medium Components for Plasmid Production by Recombinant E. coli $DH5{\alpha}$ $pUK21CMV{\beta}1.2$

Zheng, Shuzhen,Friehs, Karl,He, Ning,Deng, Xu,Li, Qingbiao,He, Zheng,Xu, Chenyun,Lu, Yinghua Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.3

In this study we investigated the effects of carbon and nitrogen sources, and the carbon to nitrogen ratio (C:N) of growth medium on the production of plasmid DNA by $pUK21CMV{\beta}1.2$ harbouring recombinant E. coli. The results indicated that sucrose and casein peptone were the most suitable carbon and nitrogen sources, respectively, for plasmid production, and the plasmid concentration was significantly influenced by the C:N ratio. A Box-Behnken design and surface response methodology were employed to formulate the optimal medium. In the optimized medium, a plasmid concentration of 51.80mg/L and a plasmid selectivity of 23.49mg/g were achieved after 24h of incubation. These values were approximately 3.5 and 1.7 times higher, respectively, than those obtained on the original LB medium.

실내 공기질 모니터링 및 분석을 위한 통합 시스템 개발

리국화(Guohua Li),김동길(Tongji Jin),변영화(Yinghua Bian),서영욱(Rongxu Xu),임상범(Sang Boem Lim) 대한공간정보학회 2015 한국지형공간정보학회 학술대회 Vol.2015 No.5

Theoretical modelling and simulation analysis of the thermal performance of a steel-basalt fiber polymer concrete machine tool joint surface

Jiaxing Shen,Zihao Pan,Ping Xu,Yinghua Yu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

The thermal performance of a steel-basalt fiber polymer concrete machine tool joint surface has a key influence on a machine tool. Based on virtual material theory, the equivalent thermal model was established and the thermal performance parameters of virtual materials were deduced by theoretical calculation. The calculation method of actual contact area ratio of steel - basalt fiber polymer concrete joint surface was established based on discrete principle and its accuracy was verified. To determine the influence of preload pressure on the actual contact area ratio, a prediction model was established. The thermal conductivity of the material was measured by the quasi-steady state method. A new systematic simulation analysis method that synthesizes virtual material theory and finite element simulation analysis was proposed, and its accuracy was verified. The results show that the relative error is only 5.01 %, which proves the method’s effectiveness.