Science and Technology Development Journal最新文献_第6页

Physical-chemical and electrochemical properties of sodium ion conducting polymer electrolyte using copolymer poly(vinylidene fluoride- hexafluoropropylene) (PVDF-HFP)/ polyethylene oxide (PEO) 聚偏氟乙烯-六氟丙烯(PVDF-HFP)/聚氧化物(PEO)共聚物钠离子导电聚合物电解质的物理化学和电化学性能

Science and Technology Development Journal Pub Date : 2019-03-29 DOI: 10.32508/STDJ.V22I1.1230

T. Vo, T. M. Phung, Hoang Quoc Duy Hoang Truong, L. Nguyen, O. H. Nguyen, P. Le

{"title":"Physical-chemical and electrochemical properties of sodium ion conducting polymer electrolyte using copolymer poly(vinylidene fluoride- hexafluoropropylene) (PVDF-HFP)/ polyethylene oxide (PEO)","authors":"T. Vo, T. M. Phung, Hoang Quoc Duy Hoang Truong, L. Nguyen, O. H. Nguyen, P. Le","doi":"10.32508/STDJ.V22I1.1230","DOIUrl":"https://doi.org/10.32508/STDJ.V22I1.1230","url":null,"abstract":"Introduction: Polymers acting as both an electrolyte and a separator are of tremendous interest because of their many virtues, such as no leakage, flexible geometry, excellent safe performance, and good compatibility with electrodes, compared with their liquid counterparts. In this study, polymer electrolyte membranes comprising of poly(vinylidene fluorine-co-hexafluoropropylene) [PVDF-HFP] were plasticized with different mass ratios of poly(ethylene oxide) (PEO) in 1 M NaClO4/PC solutions, and were prepared and characterized in sodium-ion battery. \u0000Methods: Polymer electrolyte membranes were prepared by solution-casting techniques. The membranes' performance was evaluated in terms of morphology, conductivity, electrochemical stability, thermal properties and miscibility structure. The following various characterization methods were used: Scanning Electron Microscopy (SEM), impedance spectroscopy (for determination of electrolyte resistance), cyclic voltammetry, thermal degradation analysis, and infra-red spectroscopy (for determination of structure of co-polymer). \u0000Results: It was indicated that the PVDF-HFP/PEO membrane with 40 % wt. PVDF-HFP absorbed electrolytes up to 300 % of its weight and had a roomtemperature conductivity of 2.75 x 10-3 Scm-1, which was better than that of pure PVDF-HFP. All polymer electrolyte films were electrochemically stable in the potential voltage range of 2-4.2 V, which could be compatible with 3-4 V sodium material electrodes in rechargeable sodium cells. \u0000Conclusion: The PVDF-HFP/PEO polymer electrolyte film is a potential candidate for sodium-ion battery in the potential range of 2-4.2 V. \u0000 ","PeriodicalId":285953,"journal":{"name":"Science and Technology Development Journal","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129287960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Long-term expansion enhances the expression of tumor suppressor genes in human bone marrow-derived mesenchymal stem cells 人骨髓间充质干细胞长期扩增可增强肿瘤抑制基因的表达

Science and Technology Development Journal Pub Date : 2019-03-21 DOI: 10.32508/STDJ.V22I1.1661

Loan Thi-Tung Dang, A. Bui, N. Truong, Huy Duc Van, P. Pham

{"title":"Long-term expansion enhances the expression of tumor suppressor genes in human bone marrow-derived mesenchymal stem cells","authors":"Loan Thi-Tung Dang, A. Bui, N. Truong, Huy Duc Van, P. Pham","doi":"10.32508/STDJ.V22I1.1661","DOIUrl":"https://doi.org/10.32508/STDJ.V22I1.1661","url":null,"abstract":"Introduction: Mesenchymal stem cells (MSCs) are possibly the most potent type of stem cells for the treatment of many diseases since they possess many advantageous properties, such as abundant source, ease of isolation, and potential to differentiate and trans-differentiate into different types of cells. Although the therapeutic potential of expanded MSCs has been well proven, their biosafety features have not been fully understood. This study aimed to investigate some changes in phenotype and gene expression of bone marrow derived MSCs after long term expansion. \u0000Methods: In this study, expanded mesenchymal stem cells derived from human bone marrow (hBMSCs) were identified for their characteristics (which included morphology, immunophenotype, and differentiation potential) at passages 5, 10 and 15. Moreover, they were evaluated for the expression of various tumor suppressor genes (PTEN, p16, and p53) by real-time RT-PCR. \u0000Results: The results showed that the hBMSCs at passage 15 displayed a change in morphology and a slight reduction of the expression of CD44 and CD90, whereas their potential for adipogenic and osteogenic differentiation was maintained. Moreover, the expression of tumor suppressor genes in the hBMSCs increased after long-term culture. \u0000Conclusion: It could be assumed that prolonged cultures of more than 15 passages drove the hBMSCs into senescence phase. Cultured hBMSCs below passage 10 seemed to be more effective in application because their properties were still preserved. \u0000 ","PeriodicalId":285953,"journal":{"name":"Science and Technology Development Journal","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133607887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Physical and electrochemical properties of mixed electrolyte 1-ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide and ethylene carbonate as electrolytes for Li-ion batteries 锂离子电池电解质1-乙基-3-甲基咪唑双(三氟甲烷磺酰)亚胺和碳酸乙烯混合电解质的物理和电化学性能

Science and Technology Development Journal Pub Date : 2019-02-25 DOI: 10.32508/STDJ.V22I1.837

L. Le, T. Vo, Hoang V. Nguyen, Q. Phung, M. Tran, P. Le

{"title":"Physical and electrochemical properties of mixed electrolyte 1-ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide and ethylene carbonate as electrolytes for Li-ion batteries","authors":"L. Le, T. Vo, Hoang V. Nguyen, Q. Phung, M. Tran, P. Le","doi":"10.32508/STDJ.V22I1.837","DOIUrl":"https://doi.org/10.32508/STDJ.V22I1.837","url":null,"abstract":"Introduction: Ionic liquids (ILs) have become a prospective candidate to replace the conventional electrolytes based on the volatile organic-solvents in lithium-ion batteries. However, the drawbacks of high viscosity and low ionic conductivity have restricted the high rate capacity and energy density in practical batteries. With the aims to resolve these problems and design a safe electrolytes with high electrochemical stability, mixtures of ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMITFSI) with different amounts of ethylene carbonate (EC) was prepared and characterized as electrolytes for Li-ion batteries. \u0000Methods: In this work, we investigated four factors to demonstrate the performance of EMITFSI as electrolytes for Li-ion batteries. These factors include: thermal properties of mixed electrolytes (Mettler Toledo DSC1 Star -DSC, Q500-TGA), Conductivity (HP- AC impedance spectroscopy), Viscosity (Ostwald viscometer CANNON) and electrochemical window (cyclic voltammetry-MGP2 Biologic Instrument). All experiments were repeated three times with the exception of TGA-DSC methods. \u0000Results: The study indicated that 20 % wt. ethylene carbonate (EC) when mixed with EMITFSI could significantly decrease the electrolyte viscosity while improving ionic conductivity and maintain similar electrochemical stability as pure ionic liquid. Lithium diffusion coefficient of mixed electrolytes was lower than commercial electrolytes based on conventional solvents, however, the thermal stability was enhanced. \u0000Conclusion: EMITFSI can be used to replace conventional carbonate-based liquids as a high-performance electrolyte for Li-ion batteries. \u0000 ","PeriodicalId":285953,"journal":{"name":"Science and Technology Development Journal","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125123667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Copolymerization of n-butyl acrylate/methyl methacrylate in xylene solvent 丙烯酸正丁酯/甲基丙烯酸甲酯在二甲苯溶剂中的共聚

Science and Technology Development Journal Pub Date : 2019-02-17 DOI: 10.32508/STDJ.V22I1.1020

Nguyen Vu Viet Linh, N. T. Duc, H. D. Phu

引用次数: 0

Effect of additives on shrinkage property of unsaturated polyester and mechanical properties of artificial stone 添加剂对不饱和聚酯收缩性能及人造石力学性能的影响

Science and Technology Development Journal Pub Date : 2019-02-13 DOI: 10.32508/STDJ.V16I4.1606

A. Phung, T. T. Dang

引用次数: 0

Phenolic compounds from Pamotrema dilatatum growing in Lam Dong province 生长于林同省的长叶松的酚类化合物

Science and Technology Development Journal Pub Date : 2019-01-26 DOI: 10.32508/STDJ.V22I1.1010

H. Dương

引用次数: 4

Key factors affecting on the success of ERP projects in Vietnam 影响越南ERP项目成功的关键因素

Science and Technology Development Journal Pub Date : 2019-01-14 DOI: 10.32508/STDJ.V16I2.1473

Hien Thi Nguy, Trung Pham

引用次数: 1

In vitro α-glucosidase inhibitory activity of compounds isolated from mangrove Lumnitzera littorea leaves 红树Lumnitzera littorea叶中化合物体外α-葡萄糖苷酶抑制活性的研究

Science and Technology Development Journal Pub Date : 2019-01-07 DOI: 10.32508/STDJ.V22I1.1009

T. Nguyen, T. Pham, P. Hansen, P. K. Nguyen

{"title":"In vitro α-glucosidase inhibitory activity of compounds isolated from mangrove Lumnitzera littorea leaves","authors":"T. Nguyen, T. Pham, P. Hansen, P. K. Nguyen","doi":"10.32508/STDJ.V22I1.1009","DOIUrl":"https://doi.org/10.32508/STDJ.V22I1.1009","url":null,"abstract":"Introduction: Lumnitzera littorea grown at CanGio Mangrove Forest has been investigated. The present study reports the isolation, characterization and evaluation of the alpha-glucosidase inhibitory activity of isolated compounds from Lumnitzera littorea leaves. \u0000Methods: Their structures were elucidated by spectroscopic methods (including MS, 1D and 2D–NMR) and comparison with values from the literature. From the n-hexane extract, nine compounds including lupeol (1), betulin (2), betulinic acid (3), oleanolic acid (4), corosolic acid (5), -sitosterol (6), beta-sitosterol 3-O- beta-D-glucopyranoside (7), stigmast-5-ene-3beta-O-(6-O-hexadecanoyl-beta-D-glucopyranoside) (8), and stigmast-4-ene-3-one (9) were isolated and identified. \u0000Results: The results of the alpha-glucosidase inhibitory activity showed thatcorosolic acid (5) and oleanolic acid (4) were the most potent, with IC50 values of 17.86 +/- 0.42 and 18.82 +/- 0.59 ug/mL, respectively. Five of the other seven compounds exhibited inhibitory activity with IC50 values below 100 ug/mL, and higher than the positive control acarbose (127.64 +/- 0.64 ug/mL). \u0000 ","PeriodicalId":285953,"journal":{"name":"Science and Technology Development Journal","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126194583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Study of the effects of process parameters on tool wear rate in powder mixed electrical discharge machining by Taguchi method 田口法研究粉末混合电火花加工工艺参数对刀具磨损率的影响

Science and Technology Development Journal Pub Date : 2018-12-30 DOI: 10.32508/STDJ.V20IK7.1375

P. Huu

{"title":"Study of the effects of process parameters on tool wear rate in powder mixed electrical discharge machining by Taguchi method","authors":"P. Huu","doi":"10.32508/STDJ.V20IK7.1375","DOIUrl":"https://doi.org/10.32508/STDJ.V20IK7.1375","url":null,"abstract":"There have been various attempts to improve the surface finish after Electrical Discharge Machining (EDM) by polishing and other means. But if it is possible to improve the surface during machining it will shorten the machining time. From this viewpoint powder mixed EDM (PMEDM) is one of these processes. PMEDM not only imparts fine machined surface finish but also modifies the machined surface. However, it is necessary to understand the mechanism of PMEDM process. In this study, influence of process parameters to tool wear rate (TWR) of PMEDM using titanium (Ti) powder is presented. The objective of the study is to evaluate the main effects of workpiece material, tool material, polarity, pulse-on time, intensity of discharge, pulse-off time, and powder concentration on the TWR in PMEDM. They carried out the investigation based on the Taguchi method involving seven control factors with three levels for an orthogonal array L27 (1313).The results indicated that electrode material, electrode polarity, pulse on time, current and powder concentration were the most significant parameters that influenced the TWR. This result will be the basis for selecting the factors in further optimization studies. \u0000 ","PeriodicalId":285953,"journal":{"name":"Science and Technology Development Journal","volume":"35 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124984049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Surface modification of titanium dioxide nanotubes with sulfur for highly efficient photocatalytic performance under visible light irradiation 含硫二氧化钛纳米管的表面改性及其在可见光下的高效光催化性能

Science and Technology Development Journal Pub Date : 2018-12-04 DOI: 10.32508/STDJ.V21I3.694

T. Trang, L. Tu, Co Le Thanh Tuyen, Tran Van Man, V. Thu

{"title":"Surface modification of titanium dioxide nanotubes with sulfur for highly efficient photocatalytic performance under visible light irradiation","authors":"T. Trang, L. Tu, Co Le Thanh Tuyen, Tran Van Man, V. Thu","doi":"10.32508/STDJ.V21I3.694","DOIUrl":"https://doi.org/10.32508/STDJ.V21I3.694","url":null,"abstract":"In this paper, the surface of titanium dioxide (TiO2) nanotubes (NTs) was decorated with sulfur by impregnation procedure. The crystalline structure and morphology of the S-TiO2 NT hybrid catalyst were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The chemical components of S-TiO2 NT-1 sample were analyzed by energy dispersive X-ray (EDX). The results showed that sulfur impurities were incorporated into TiO2 crystal structure and decorated on its surface due to the heat treatment temperature used throughout the fabrication process. Moreover, its photocatalytic reaction was evaluated by change of adsorption intensity of methyl orange (MO) aqueous solution at wavelength of 467 nm. This work revealed that the sulfur loaded onto TiO2 NT nanostructures exhibited excellent photocatalytic efficacy for the degradation of the MO dye compared with pristine TiO2 NTs (93.12 ± 0.02% and 80.21 ± 0.04% MO degradation efficacy under UV light versus visible-light regime, respectively, after 180 minutes). This was mainly governed by sulfur ions modified on the surface of TiO2 NTs which played a critical role in promoting the separation rate of photo-induced charge carriers. \u0000 ","PeriodicalId":285953,"journal":{"name":"Science and Technology Development Journal","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122919049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2