http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Shanjun Gao (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
Li Zhen,Shi Chao,Gao Shanjun,Zhang Xiulei,Lu Di,Liu Guangzhi 한국미생물학회 2020 The journal of microbiology Vol.58 No.12
The Gram-positive bacterium Enterococcus faecalis is currently one of the major pathogens of nosocomial infections. The lifestyle of E. faecalis relies primarily on its remarkable capacity to face and survive in harsh environmental conditions. Toxin-antitoxin (TA) systems have been linked to the growth control of bacteria in response to adverse environments but have rarely been reported in Enterococcus. Three functional type II TA systems were identified among the 10 putative TA systems encoded by E. faecalis ATCC29212. These toxin genes have conserved domains homologous to MazF (DR75_ 1948) and ImmA/IrrE family metallo-endopeptidases (DR75_ 1673 and DR75_2160). Overexpression of toxin genes could inhibit the growth of Escherichia coli. However, the toxin DR75_1673 could not inhibit bacterial growth, and the bacteriostatic effect occurred only when it was coexpressed with the antitoxin DR75_1672. DR75_1948–DR75_1949 and DR75_ 160–DR75_2161 could maintain the stable inheritance of the unstable plasmid pLMO12102 in E. coli. Moreover, the transcription levels of these TAs showed significant differences when cultivated under normal conditions and with different temperatures, antibiotics, anaerobic agents and H2O2. When DR75_2161 was knocked out, the growth of the mutant strain at high temperature and oxidative stress was limited. The experimental characterization of these TAs loci might be helpful to investigate the key roles of type II TA systems in the physiology and environmental stress responses of Enterococcus.
-
Zhihui Wu,Chunhui Shen,Shanjun Gao,Xi Zhu,Mingliang Zhang,Ao Ding 한국고분자학회 2021 Macromolecular Research Vol.29 No.3
A series of proton exchange membranes were prepared by incorporating phosphonic functionalized siloxane into sulfonic poly(2,6-dimethyl-1,4-phenyleneoxide) (SPPO) and imidazole functionalized poly(2,6-dimethyl-1,4-phenyleneoxide) grafted with siloxane (IPPO-Si). Phosphonic acid functionalized siloxane was synthesized from amino trimethyl phosphonic acid (ATMP) and (3-aminopropyl)triethoxysilane (APTES). FTIR results showed that 1-methylimidazole and APTES were successfully grafted onto polyphenylene oxide, and APTES successfully formed Si-O-Si crosslinked networks through hydrolytic crosslinking. The membranes were thermally stable up to 220 °C and exhibited excellent oxidative stability and mechanical performance. We also measured the proton conductivity of the membranes. The results showed that the proton conductivities of the composite membranes increased with the increasing of SPPO content at different degrees under high (100 °C-160 °C) and low (25 °C-80 °C) temperature conditions. Furthermore, the IPPO-SI-P/SPPO-30 has the best conductivity, reaching to 0.1131 S cm-1 at 80 °C, 100%RH and 0.1049 S cm-1 at 160 °C, 5%RH, respectively. Therefore, this novel membrane acts as a potential candidate for proton exchange membranes with a wider applicable temperature (25 °C-160 °C).
-
Xuechao Ren,Chunhui Shen,Shanjun Gao,Yuan Yuan,Jiqin Chen 한국고분자학회 2018 Macromolecular Research Vol.26 No.2
A novel proton exchange membrane which can be applied in the range of 25-140°C is prepared by incorporating phosphonic acid functionalized crosslinked siloxane in sulfonated poly(ether ether ketone) matrix from amino trimethylene phosphonic acid (ATMP), epoxycyclohexylethyltrimethoxysilane (EHTMS), and sulfonated poly(ether ether ketone) (SPEEK). EHTMS is introduced to chemically fix free ATMP as well as a cross-linker. And, the obtained membranes are immersed in deionized water to remove free ATMP. Fourier transform infrared and X-ray diffraction patterns suggest that ATMP is anchored into EHTMS and Si-O-Si network forms successfully. These membranes are thermally stable up to 220 °C and exhibit excellent dimensional stability and mechanical performance. The addition of ATMP not only increases the amount of proton transfer sites, but also provides proton transport units for membranes at elevated temperature and low relative humidity (RH) condition. The proton conductivity of AES-4 membrane reaches 0.114S cm-1 at 80 °C and 100%RH and 0.056 Scm-1 at 140 °C and 20%RH, respectively.
-
Zhenghan Li,Junjie Chen,JinYue Zhou,YiWen Nie,Chunhui Shen,Shanjun Gao 한국고분자학회 2021 Macromolecular Research Vol.29 No.7
The main chain of polyolefin was synthesized by copolymerization of 4 - vinylbenzyl chloride (VBC) and acrylonitrile (AN), and trimethylamine is used for quaternization to prepare heterogeneous benzyl trimethyl-ammonium anion exchange membranes (Heter-X) and homogeneous benzyl trimethyl-ammonium anion exchange membrane (Homo-X). The results of Fourier-transform infrared (FT-IR), gel permeation chromatography (GPC), and 1H nuclear magnetic resonance (NMR) showed that VBC and AN were successfully copolymerized to form a polymer with a certain molecular weight, and trimethylamine was successfully quaternized. The prepared membranes exhibited good thermal stability and mechanical properties. The theoretical ion exchange capacity (IEC) values of Homo-3 and Heter-3 are the same, but the conductivity at 80 °C were 0.0572 S cm-1 and 0.0505 S cm-1. The results showed that the homogeneous method has a higher degree of quaternization and a more uniform distribution of quaternary ammonium groups, forming a more obvious microphase separation structure, which can also be seen in the atomic force microscopy (AFM) diagram. After being soaked in 1M KOH solution for 480 h, the ionic conductivity of Homo-6 and Heter-6 can still remain 91.4% and 85.5%, and the IEC loss rates were 17.21% and 24.34%. These results indicate that the prepared membranes are promising materials for application in fuel cells.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
