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On overrings of Gorenstein Dedekind domains
Kui Hu,Fanggui Wang,Longyu Xu,Songquan Zhao 대한수학회 2013 대한수학회지 Vol.50 No.5
In this paper, we mainly discuss Gorenstein Dedekind domains (G-Dedekind domains for short) and their overrings. Let R be a one-dimensional Noetherian domain with quotient field K and integral closure T. Then it is proved that R is a G-Dedekind domain if and only if for any prime ideal P of R which contains (R:KT), P is Gorenstein projective. We also give not only an example to show that G-Dedekind domains are not necessarily Noetherian Warfield domains, but also a definition for a special kind of domain: a 2-DVR. As an application, we prove that a Noetherian domain R is a Warfield domain if and only if for any maximal ideal M of R, RM is a 2-DVR.
ON OVERRINGS OF GORENSTEIN DEDEKIND DOMAINS
Hu, Kui,Wang, Fanggui,Xu, Longyu,Zhao, Songquan Korean Mathematical Society 2013 대한수학회지 Vol.50 No.5
In this paper, we mainly discuss Gorenstein Dedekind do-mains (G-Dedekind domains for short) and their overrings. Let R be a one-dimensional Noetherian domain with quotient field K and integral closure T. Then it is proved that R is a G-Dedekind domain if and only if for any prime ideal P of R which contains ($R\;:_K\;T$), P is Gorenstein projective. We also give not only an example to show that G-Dedekind domains are not necessarily Noetherian Warfield domains, but also a definition for a special kind of domain: a 2-DVR. As an application, we prove that a Noetherian domain R is a Warfield domain if and only if for any maximal ideal M of R, $R_M$ is a 2-DVR.
Shi Lingling,Xu Yongjun,Li Kang,Yao Zhongping,Wu Songquan 한국물리학회 2010 Current Applied Physics Vol.10 No.3
In order to improve the corrosion resistance of ceramic coatings formed on Mg–5mass%Li substrate by micro-arc oxidation (MAO) method, two kinds of additives (Na2B4O7 and EDTA) were doped in Na2SiO3–Na3PO4 solution system. The surface and cross-section morphology feature, phase composition and elemental composition were examined by SEM, XRD and EDX, respectively. Corrosion resistance of ceramic coating was tested by electrochemical methods. It was revealed that all coatings were composed of MgO and Mg2SiO4, and had porous surface structure. Doping of additives had little effect on the elemental composition, while it influenced the morphological feature of the coating. The results of electrochemical tests showed that the coatings prepared in the solutions with additive had good corrosion resistance. The addition of EDTA to the solution made coatings thinner and more uniform which resulted in better general corrosion resistance. The addition of Na2B4O7 to the solution made coatings much thicker and compacter, which improved the pitting corrosion resistance.
( Fei-liang Zhong ),( Rui Ma ),( Mingliang Jiang ),( Wei-wei Dong ),( Jun Jiang ),( Songquan Wu ),( Donghao Li ),( Lin-hu Quan ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.10
The ginsenoside-hydrolyzing β-glucosidase gene (bgy2) was cloned from Lactobacillus brevis. We expressed this gene in Escherichia coli BL21(DE3), isolated the resulting protein, and then utilized the enzyme for the biotransformation of ginsenosides. The bgy2 gene contains 2,223 bp, and encodes a protein of 741 amino acids that is a member of glycosyl hydrolase family 3. β-Glucosidase (Bgy2) cleaved the outer glucose moieties of ginsenosides at the C-20 position, and the inner glucose at the C-3 position. Under optimal conditions (pH 7.0, 30˚C), we used 0.1 mg/ml Bgy2 in 20 mM sodium phosphate buffer (PBS) for enzymatic studies. In these conditions, 1.0 mg/ml ginsenoside Rb1 and ginsenoside F2 were converted into 0.59 mg/ml ginsenoside Rd and 0.72mg/ml compound K, with molar conversion productivities of 69% and 91%, respectively. In pharmaceutical and commercial industries, this recombinant Bgy2 would be suitable for producting ginsenoside Rd and compound K.
Yongbo Guo,Zheyingzi Zhu,Dekun Zhang,Kai Chen,Songquan Wang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.3
An experiment was conducted using a microslip friction test machine to measure reciprocating sliding friction between a K25 friction lining and a 6 × 19 steel wire rope under dynamic loading. Real-time in situ microscopic observation of the interfacial friction in the contact were performed by using a high-speed micro camera. The results showed that during the loading and unloading stages of friction, adhesion, partial adhesion and slip states were observed. The friction coefficient decreases with increasing dynamic load. In the lightly loaded area (3kN-10kN), the variation of the friction coefficient in the sliding stage was stable. In the heavily loaded area (3kN-14kN), the friction coefficient in the slip stage decreased with increasing load, and the proportion of the slip stage in the loading time increased. The wear debris generated at the interface of the contact increased gradually with increasing dynamic load. Then, a dense third body formed, which reduced the friction coefficient. The wear rate of the lining under these experimental conditions was 3.23 × 10–4 after 18 h.
Biotransformation of Panax ginseng extract by rat intestinal microflora
Wei-Wei Dong,Jinhua Zhao,Fei-Liang Zhong,Wen-Jing Zhu,Jun Jiang,Songquan Wu,Deok-Chun Yang,Donghao Li,Lin-Hu Quan 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.4
Background: In general, after Panax ginseng is administered orally, intestinal microbes play a crucial role in its degradation and metabolization process. Studies on the metabolism of P. ginseng by microflora are important for obtaining a better understanding of their biological effects. Methods: In vitro biotransformation of P. ginseng extract by rat intestinal microflora was investigated at 37C for 24 h, and the simultaneous determination of the metabolites and metabolic profile of P. ginseng saponins by rat intestinal microflora was achieved using LCeMS/MS. Results: A total of seven ginsenosides were detected in the P. ginseng extract, including ginsenosides Rg1, Re, Rf, Rb1, Rc, Rb2, and Rd. In the transformed P. ginseng samples, considerable amounts of deglycosylated metabolite compound K and Rh1 were detected. In addition, minimal amounts of deglycosylated metabolites (ginsenosides Rg2, F1, F2, Rg3, and protopanaxatriol-type ginsenosides) and untransformed ginsenosides Re, Rg1, and Rd were detected at 24 h. The results indicated that the primary metabolites are compound K and Rh1, and the protopanaxadiol-type ginsenosides were more easily metabolized than protopanaxatriol-type ginsenosides. Conclusion: This is the first report of the identification and quantification of the metabolism and metabolic profile of P. ginseng extract in rat intestinal microflora using LCeMS/MS. The current study provided new insights for studying the metabolism and active metabolites of P. ginseng.
Dong, Wei-Wei,Zhao, Jinhua,Zhong, Fei-Liang,Zhu, Wen-Jing,Jiang, Jun,Wu, Songquan,Yang, Deok-Chun,Li, Donghao,Quan, Lin-Hu The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.4
Background: In general, after Panax ginseng is administered orally, intestinal microbes play a crucial role in its degradation and metabolization process. Studies on the metabolism of P. ginseng by microflora are important for obtaining a better understanding of their biological effects. Methods: In vitro biotransformation of P. ginseng extract by rat intestinal microflora was investigated at $37^{\circ}C$ for 24 h, and the simultaneous determination of the metabolites and metabolic profile of P. ginseng saponins by rat intestinal microflora was achieved using LC-MS/MS. Results: A total of seven ginsenosides were detected in the P. ginseng extract, including ginsenosides Rg1, Re, Rf, Rb1, Rc, Rb2, and Rd. In the transformed P. ginseng samples, considerable amounts of deglycosylated metabolite compound K and Rh1 were detected. In addition, minimal amounts of deglycosylated metabolites (ginsenosides Rg2, F1, F2, Rg3, and protopanaxatriol-type ginsenosides) and untransformed ginsenosides Re, Rg1, and Rd were detected at 24 h. The results indicated that the primary metabolites are compound K and Rh1, and the protopanaxadiol-type ginsenosides were more easily metabolized than protopanaxatriol-type ginsenosides. Conclusion: This is the first report of the identification and quantification of the metabolism and metabolic profile of P. ginseng extract in rat intestinal microflora using LC-MS/MS. The current study provided new insights for studying the metabolism and active metabolites of P. ginseng.