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7篇 您的检索式:作者名="Kewen Yu"
    题名 作者 年代 出处 被引量
1Equilibrium of liquid-liquid extraction of 2-phenylbutyric acid enantiomers: Experiment and model显示文摘The utilization of liquid–liquid extraction for the separation of 2-phenylbutyric acid(2-PBA) enantiomers was proposed. Factors affecting the extract process were investigated, including organic solvents, β-cyclodextrin derivatives, cyclodextrin concentration, p H and temperature. A model was proposed to describe the separation process based on the homogeneous phase reaction mechanism. Important parameters of this model were determined experimentally. The physical distribution coefficients for molecular and ionic 2-PBA were0.129 and 7.455, respectively. The equilibrium constants of the complexation reactions were 89.36 and36.78 L·mol^(-1) for(+)-and(-)-2-PBA, respectively. The model was verified by experiments and proved to be an excellent means to optimize the separation system. Through modeling prediction and experiment, the best conditions(e.g., pH value of 3.00, extractant concentration of 0.1 mol·L^(-1), temperature of 5.0 °C) were acquired. Under this condition, the maximum enantioselectivity(2.096) was obtained.Weifeng Xu Guilin Dai Kewen Tang Panliang Zhang Biquan Xiong Yu Liu 2018Chinese Journal of Chemical Engineering2018,26,4:2
2Non-target Screening and Quantitation of Organic Chlorides in Oilfield Chemicals with Comprehensive Two Dimensional Gas Chromatography Coupled with Time of Flight Mass Spectrometry显示文摘Advanced analytical methodology based on comprehensive two-dimensional gas chromatography-time of flight mass spectrometry(GC×GC-TOFMS) is proposed for investigation of organic chlorides in different oilfield chemicals.The target screening was initially carried out on 8 suspected organic chlorides by evaluating the capability of the enhanced separation and reliable identification at a trace concentration. GC×GC-TOFMS allowed for the fast and automated analysis of organic chlorides at a level of 200 μg/L. This method was subsequently applied for non-target screening of organic chlorides in different oilfield chemicals at various locations across China. 22 organic chlorides were identified and verified by comparison with pure standards in the mixed sample. Finally, this method was used to determine the content of the organic chlorides in individual samples. The result showed that the organic chloride levels in 19 of the 39 tested oilfield chemicals were above the threshold limit of 1.0 mg/L.Zheng Kewen Guo Rui Ren Guofa Xia Lingyan Xiong Wei Zhang Jin Chu Xiaodong Yu Zhiqiang 2017China Petroleum Processing & Petrochemical Technology2017,19,4:1
3Mechanoresponsive MiR-138-5p Targets MACF1 to Inhibit Bone Formation显示文摘Mechanical stimuli play an essential role in maintaining bone remodeling and skeletal integrity.Meanwhile,bone can respond to the changes of mechanical condition to adjust its mass and architecture.Clinical studies discover that bedridden patients showed osteoporotic T-scores and low bone mineral density,and long-term immobilized patients presented reduced markers of bone formation.However,as bone formation mediated by osteoblast differentiation is a complex process,the underlying molecular mechanism of mechanical stimuli regulating bone formation is still unclear.Recent evidences show that microRNAs(miRNAs)are involved in mechanical stimuli regulating bone formation or osteoblast differentiation.Nevertheless,no direct evidence identifies mechanoresponsive miRNA in both human and animal bones,and clarifies its mechanoresponsive role under different mechanical conditions(e.g.mechanical unloading,reloading,loading).In the current study,we screened for differentially expressed miRNAs in bone specimens of bedridden patients with fractures,then identified that the expression of miR-138-5p,but not the other miRNAs,altered withbedridden time and was negatively correlated with the expression of the bone formation marker genes Alp(alkaline phosphatase).Moreover,miR-138-5p was up-regulated with reduced bone formation during unloading and down-regulated with increased bone formation during reloading in hind4imb unloaded mice.In addition,miR-138-5p was verified to be responsive to different mechanical unloading condition and cyclic mechanical stretch condition in primary osteogenic cells,respectively.Further in vitro data suggested that mechanoresponsive miR-138-5p directly targeted microtubule actin crosslinking factor 1(MACF1)to inhibit osteoblast differentiation.In vivo,we constructed an osteoblastic miR-138-5p transgenic mice model(TG138)with the Runx2promoter,and found that overexpression miR-138-5p supressed bone formation.Moreover,osteoblast-targeted inhibition of miR-138-5p sensitized bone anabolic response to mechanical loading in TG138 mice.Predominantly,the osteoblast-targeted inhibition of miR-138-5p could counteract bone formation reduction induced by hind limb unloading.Taken together,the mechanoresponsive miR-138-5p inhibited bone anabolic response for developing a novel bone anabolic sensitization strategy.Zhihao Chen Zhao Fan Liang Chao Lifang Hu Chen Lei Zhang Yan Yin Chong Dijie Li Tian Ye Wuxia Qiu Kewen Zhang Chaofei Yang Xiaona Li Li Yu Weiyi Chen Zhang Ge Qian Airong 2019医用生物力学2019,34,A01:1
4Musks and organochlorine pesticides in breast milk from Shanghai, China: Levels, temporal trends and exposure assessment显示文摘Jing Zhou Xiangying Zeng Kewen Zheng Xuejing Zhu Li Ma Qing Xu Xiaolan Zhang Yingxin Yu Guoying Sheng Jiamo Fu 2012Ecotoxicology and Environmental Safety2012,,:1
5Study on extraction kinetics ofα-cyclopentylmandelic acid enantiomers with hydroxyethyl-β-cyclodextrin as chiral selector显示文摘In this work,the kinetic study on reactive extraction ofα-cyclopentylmandelic acid(α-CPMA)enantiomers was performed in a Lewis cell using hydroxyethyl-β-cyclodextrin(HE-β-CD)as chiral selector.The enantioselective complexation equilibrium between HE-β-CD andα-CPMA enantiomers was studied by phase solubility method.The important process parameters affecting the initial extraction rate were separately studied and the reaction rate equations were deduced.The optimal conditions for kinetic study were as follows:stirring speed of 75 r·min^(-1),interfacial area of 12.56 cm^2,pH of 2.5,initial HE-β-CD concentration of 0.05 mol·L^(-1),initialα-CPMA concentration of 5 mmol·L^(-1),and temperature of 278 K.The reaction has been found to be first order inα-CPMA and second order in HE-β-CD with the forward rate constants of 2.056×10^(-3)m^6·mol^(-2)·s^(-1)and 1.459×10^(-3)m^6·mol^(-2)·s^(-1)for(S)-α-CPMA and(R)-α-CPMA,respectively.The complexation equilibrium constants were evaluated as 61 L·mol^(-1) and 117 L·mol^(-1)for(S)-α-CPMA and(R)-α-CPMA,and the intrinsic enantioselectivity is estimated as 1.92.Panliang Zhang Pan Jiang Weifeng Xu Yu Liu Biquan Xiong Yunren Qiu Kewen Tang 2018Chinese Journal of Chemical Engineering2018,26,1:0
6Vertical graphene-coated Cu wire for enhanced tolerance to high current density in power transmission显示文摘Cu wires(CuWs)are widely used as electric transmission lines.However,their limited thermal and chemical stabilities become challenges under the high-power and harsh environment.Graphene is regarded as an ideal protective barrier for CuW benefiting from its impermeability to all atoms and molecules.Particularly,the excellent hydrophobicity of vertical graphene(VG)will strengthen its protective capability as a corrosion and oxidation barrier.Herein,VG is directly synthesized on CuW by plasmaenhanced chemical vapor deposition method.The hydrophobic VG coating with a high water contact angle can effectively exclude the corrosive liquid and moisture from CuW surface and prevent their further penetration.Consequently,the electrochemical corrosion rate of VG-CuW is reduced by~13,8,and 2 times,compared with bare CuW,VG-CuW with hydrophilic treatment,and CuW coated with thick horizontal graphene layers,respectively.Negligible oxidation occurs on VGCuW after the long-time exposure to humid air at~200℃ along with the largely enhanced tolerance under high-current operating condition.This study reveals the impressive potentials of hydrophobic VG as a robust corrosion and oxidation barrier for metal wires used in high-power cables and electronic devices in harsh environment.Kun Wang Shuting Cheng Qingmei Hu Feng Yu Yi Cheng Kewen Huang Hao Yuan Jun Jiang Wenjuan Li Junliang Li Shichen Xu Jianbo Yin Yue Qi Zhongfan Liu 2022Nano Research2022,15,11:0
7Development of a New in-situ Interface Shear Box Test Apparatus and Its Applications显示文摘INTRODUCTION Interfaces are often seen in various geotechnical materials,such as soil-bedrock interfaces(Yang et al.,2020;Gabet et al.,2006),soil-structure interfaces(Ilori et al.,2017;di Donna et al.,2016),and interfaces between soils with different properties(Zhu et al.,2022).Kewen Yu Ling Xu Jianbing Peng Lu Zuo Guangxi Guan 2023Journal of Earth Science2023,34,3:0
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