检索结果-南通市图书馆

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

地榆中酚类成分及其Nrf2激动活性研究

药学学报 2024年第1期59卷 170-182页

作者：吴龙龙刘静雯余钟莲张刘强李医明上海中医药大学中药学院上海201203 上海中医药大学科技实验中心上海201203

采用大孔树脂、硅胶、ODS、Sephadex LH-20、半制备HPLC等多种色谱技术从地榆饮片(Sanguisorbae Radix)的95%乙醇提取物中分离纯化得到31个酚类化合物,通过理化性质、波谱数据(MS、NMR)、电子圆二色谱(ECD)等技术确定化合物的结构,分别... 详细信息

采用大孔树脂、硅胶、ODS、Sephadex LH-20、半制备HPLC等多种色谱技术从地榆饮片(Sanguisorbae Radix)的95%乙醇提取物中分离纯化得到31个酚类化合物,通过理化性质、波谱数据(MS、NMR)、电子圆二色谱(ECD)等技术确定化合物的结构,分别鉴定为3-methoxyl-2S,3S-epoxyflavanone(1a)、3-methoxyl-2R,3R-epoxyflavanone(1b)、longifoin B(2)、longifoin C(3)、圣草酚(4)、柚皮素(5)、甘草素(6)、5,3?-二羟基-7,4?-二甲氧基二氢黄酮(7)、柚皮素-7-O-β-D-葡萄糖苷(8)、二氢槲皮素(9)、二氢山柰酚(10)、(-)-garbanzol(11)、(2R,3R)-4-methoxyl-distylin(12)、山柰酚(13)、槲皮素(14)、α,4,2′,4′-tetrahydroxydihydrochalcone(15)、phloretin(16)、(+)-儿茶素(17)、ethyl(+)-cyanidan-3-ol-8-carboxylate(18)、phyllocoumarin(19)、methyl 3-methoxy-4,5-dihydroxybenzoate(20)、4,5-dimethoxy-3-hydroxybenzoicacidmethylester(21)、3,4′-di-O-methylellagicacid(22)、3,4,3′-三甲基逆没食子酸(23)、3,3?,4?-Otrimethylellagic acid-4-O-β-D-xyloside(24)、(3R)-thunberginol C(25)、resveratrol(26)、1-hydroxypinoresinol(27)、(7S,8S)-3-methoxy-3′,7-epoxy-8,4′-oxyneoligna-4,9,9′-triol(28)、大黄素-8-O-β-D-葡萄糖苷(29)、phloracetophenone(30)和4-(4′-hydroxyphenyl)-butan-2-one(31)。其中化合物1a和1b为一对新的2,3-环氧黄酮对映异构体,化合物2和3为一对新的差向异构体,化合物4、5、6、9、10、13、16和26为首次从该植物中分离得到,化合物7、8、27、30和31为首次从该属植物中分离得到,化合物11、12、15、18、19、25、28和29为首次从蔷薇科植物中分离得到。通过双荧光素酶报告基因实验在293T细胞中测定化合物1~24对核因子-红细胞2相关因子2(nuclear factor erythroid 2-related factor 2,Nrf2)的激动活性,结果表明,化合物4、6~10、12、14、17、19、20和22~24对Nrf2在25μmol·L-1下表现出显著的促转录活性,为该类化合物的抗氧化活性研究提供参考。

关键词：地榆酚类成分黄酮 2 3-环氧黄酮 Nrf2激动活性抗氧化

Facial Image Attributes Transformation via Conditional Recycle Generative Adversarial Networks

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2018年第3期33卷 511-521页

作者： Huai-yu Li Wei-ming Dong Bao-Gang Hu National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

This study introduces a novel conditional recycle generative adversarial network for facial attribute transfor- mation, which can transform high-level semantic face attributes without changing the identity. In our approach, we input a source facial image to the conditional generator with target attribute condition to generate a face with the target attribute. Then we recycle the generated face back to the same conditional generator with source attribute condition. A face which should be similar to that of the source face in personal identity and facial attributes is generated. Hence, we introduce a recycle reconstruction loss to enforce the final generated facial image and the source facial image to be identical. Evaluations on the CelebA dataset demonstrate the effectiveness of our approach. Qualitative results show that our approach can learn and generate high-quality identity-preserving facial images with specified attributes.

关键词： generative adversarial network image editing facial attributes transformation

Isothermal Crystallization of iPP in Environment-friendly Diluents:Effect of Binary Diluents and Crystallization Temperature on Crystallization Kinetics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2019年第6期37卷 617-626页

作者： yu-Jie Wang Su-Ying Yan Zhi-Ping zhao Zhen-yu Xi School of Chemistry and Chemical Engineering Beijing Institute of Technology Environmental Protection Research Institute Beijing Research Institute of Chemical IndustrySINOPEC

The growing demand for non-toxic solvents for membrane preparation has motivated the studies for green and sustainable alternatives of solvents. The effect of droplet isothermal growth within the liquid-liquid phase separation region on isothermal spherulitic growth rate of isotactic polypropylene(iPP) was investigated. The results showed that the droplets grew up at a rate of 0.0172 μm·s^(-1). The larger droplets slowed down the isothermal spherulitic growth rate of iPP. Higher mass ratio of carnauba wax(Cwax)/soybean oil(SO)resulted in faster droplet growth due to weak interaction with polymers. The isothermal crystallization behaviors of iPP in environmentfriendly binary diluents consisting of Cwax and SO mixture were further investigated experimentally using polarized optical *** was demonstrated that the isothermal spherulitic growth rate of iPP in diluents decreased nonlinearly with the increasing crystallization temperature. Compared with virgin iPP, isothermal spherulitic growth rate of iPP in SO diluent was significantly slowed down. The spherulitic growth was further retarded after the addition of Cwax in mixed diluents, resulting in a lower crystallization rate than that in SO. Moreover, the crystal form of iPP membranes was found to be α type through the characterization of small angle X-ray scattering and wide angle X-ray diffraction.

关键词： Isotactic polypropylene Carnauba wax Isothermal crystallization kinetics PP membrane

Numerical Simulation of Wave Scour Around A Large-Scale Circular Cylinder

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2002年第4期17卷 513-523页

作者： zhao ming(赵明) TENG Bin(滕斌) LIU Shu-xue(柳淑学) Stake Key Laboratory of Coastal and Offshore Engineering.Dalian University of Technology Dalian 116024 China Stake Key Laboratory of Coastal and Offshore Engineering.Dalian University of Technology Dalian 116024 China Stake Key Laboratory of Coastal and Offshore Engineering.Dalian University of Technology Dalian 116024 China

A numerical model is developed for estimation of local scour around a large circular cylinder under wave action. The model includes wave diffraction around structures, bed shear stress calculation inside the wave boundary layer and topographical change model. The wave model is based on the unproved Boussinesq equations for varying depth. The wave boundary layer is calculated by solving the integrated momentum equation over the boundary layer. The bed shear strew due to streaming, an important factor affecting die sediment transport around a large-scale cylinder, is calculated. The Lagrangian drift velocity is included in calculation of the suspended sediment transport rates. The model is implemented by a finite element method and the results from the present model, which agree well with experimental data, are compared with those from other methods.

关键词： local scour Boussinesq equations numerical simulation circular cylinder

陆相中高成熟页岩油“组分流动”条件及其在提高页岩油产量中的作用

在线全文

学校读者我要写书评

暂无评论

石油勘探与开发 2024年第4期51卷 720-730页

作者：赵文智卞从胜李永新刘伟秦冰蒲秀刚江建林刘诗局关铭董劲申玉坦中国石油勘探开发研究院北京100083 中国石油勘探开发研究院赵文智院士工作室北京100083 中国石化石油化工科学研究院北京100083 中国石油大港油田公司勘探开发研究院天津300280

基于中国陆相页岩油区重点试采井的生产曲线、生产制度、烃产物数量和产出烃构成随时间的变化等资料,开展页岩油精细馏分切割和页岩油组成变化对宏观流动性影响的试验以及分子动力学数值模拟,提出页岩油“组分流动”概念,并对组分流动... 详细信息

基于中国陆相页岩油区重点试采井的生产曲线、生产制度、烃产物数量和产出烃构成随时间的变化等资料,开展页岩油精细馏分切割和页岩油组成变化对宏观流动性影响的试验以及分子动力学数值模拟,提出页岩油“组分流动”概念,并对组分流动的形成机理与条件进行探讨。研究表明:(1)在地下页岩微纳米孔隙中,轻烃、中质烃和重烃会按相似相溶原理发生混相,使重烃等难流动组分以分子聚集体方式“悬浮”在轻烃和中质烃溶剂中,从而显著降低其黏度并增加流动性和流动量;(2)小分子芳烃是组分流动发生的载体,气态烃和轻烃含量越高,越利于抑制胶质和沥青等重组分形成尺寸更大的聚集体,并增加其塑性变形能力,组分流动效果越好;(3)较高的地层温度可降低蜡质等重烃组分黏度,提高其流动性;(4)保存条件、地层能量和生产制度对控制轻烃组分含量、流出速度和形成稳定的“组分流动”都有重要作用,是页岩油多组分烃形成最优配伍和最大流动量的重要影响因素。地下页岩油“组分流动”概念的提出对于提高页岩油单井产量和累计采出量具有重要意义。

关键词：陆相纯页岩型页岩油中高成熟页岩油微纳米孔隙多组分烃组分流动相似相溶分子聚集体

Structural and electrical properties of HCl–polyaniline–Ag composites synthesized by polymerization using Ag-coated (NH_4)_2S_2O_8 powder

同方期刊数据库

同方期刊数据库更多评论

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2018年第11期25卷 1329-1334页

作者： You Zhou yu-he Zhang Jun-sheng Ma ming-peng yu Hong Qiu School of Mathematics and Physics University of Science and Technology Beijing

Ag nanoparticles were sputter-deposited on ammonium persulfate((NH_4)_2S_2O_8) powder to obtain(NH_4)_2S_2O_8-Ag powder, which was used to synthesize the HCl-doped polyaniline-Ag(HCl-PANI-Ag) composite via a polymerization procedure. The Ag nanoparticles were dispersed in the HCl-PANI matrix, and their sizes mainly ranged from 3 to 6 nm. The Ag nanoparticles did not affect the structure of emeraldine salt in the composite, and they increased the ordered crystalline regions in the HCl-PANI matrix. The HCl-PANI-Ag composite had a conductivity of(6.8 ± 0.1) S/cm, which is about four times larger than that of the HCl-PANI. The charge transport mechanism in the composite is explained by the three-dimensional Mott variable-range hopping(3D-Mott-VRH).

关键词： hydrochloric-acid-doped polyaniline silver nanoparticles composite structure conductivity

宁夏部分地区哺乳期奶犊牛群中腹泻相关病原流行病学调查

在线全文

学校读者我要写书评

暂无评论

西北农业学报 2024年第9期33卷 1599-1613页

作者：崔省委赵清梅于鲲薛佳祺孙若菡李勇马云余永涛宁夏大学动物科技学院银川750021 北方民族大学生物科学与工程学院银川750021 宁夏大学生命科学学院银川750021

为了解宁夏地区哺乳期奶犊牛群中腹泻相关病原的流行情况,采用PCR和RT-PCR法对采自宁夏4个地区、18个规模化奶牛场的334份哺乳期犊牛粪便样品分别进行牛轮状病毒(Bovine rotavirus, BRV)、牛冠状病毒、牛病毒性腹泻病毒、牛诺如病毒(Bov... 详细信息

为了解宁夏地区哺乳期奶犊牛群中腹泻相关病原的流行情况,采用PCR和RT-PCR法对采自宁夏4个地区、18个规模化奶牛场的334份哺乳期犊牛粪便样品分别进行牛轮状病毒(Bovine rotavirus, BRV)、牛冠状病毒、牛病毒性腹泻病毒、牛诺如病毒(Bovine norovirus, BNoV)、牛纽布病毒、牛星状病毒、牛环曲病毒、牛嵴病毒(Bovine kobuvirus, BKoV)、牛肠道病毒、隐孢子虫、艾美耳球虫、贾第鞭毛虫、K99型大肠杆菌和沙门氏菌14种腹泻相关病原的检测,并对各种病原的流行特点和主要流行病原的遗传进化关系进行分析。结果显示,从宁夏地区哺乳犊牛粪便中共检出13种腹泻相关病原,其中隐孢子虫(38.02%)、BRV(19.76%)、BKoV(18.56%)和BNoV(13.77%)检出率较高,隐孢子虫、BRV和BKoV在腹泻犊牛粪便中的检出率显著高于健康犊牛(P<0.05)。单一病原感染类型占比显著高于两种或两种以上病原混合感染的类型(P<0.05)。在宁夏4个地区、3个季节采集的样品中,隐孢子虫、BRV、BKoV和BNoV检出率相对较高,在1~30日龄犊牛群中隐孢子虫、BRV和BKoV检出率较高,在31~60日龄犊牛中隐孢子虫和BNoV检出率较高,在60日龄以上的哺乳犊牛中BKoV、BEV和隐孢子虫检出率较高。遗传进化分析结果显示,哺乳犊牛感染的隐孢子虫主要为微小隐孢子虫,BRV主要为A型轮状病毒,BKoV主要为B型爱知病毒,BNoV主要为GⅢ.2型诺如病毒。以上结果表明,隐孢子虫、BRV、BKoV和BNoV是宁夏地区哺乳期奶犊牛群中主要流行的腹泻相关病原,并与犊牛腹泻的发生关系密切。单一病原感染是哺乳期奶犊牛腹泻相关病原感染的主要类型。犊牛感染的病原种类与季节和日龄关系密切。

关键词：哺乳期奶犊牛犊牛腹泻病原流行病学调查

维普期刊数据库博看期刊

Coordinated chaos control of urban expressway based on synchronization of complex networks

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第11期27卷 672-682页

作者： ming-bao Pang yu-man Huang School of Civil and Transportation Hebei University of Technology Tianjin 300401 China

We investigate the problem of coordinated chaos control on an urban expressway based on pinning synchronization of complex networks. A node coupling model of an urban expressway based on complex networks has been established using the cell transmission model（CTM）. The pinning controller corresponding to multi-ramp coordinated controller was designed by using the delayed feedback control（DFC） method, whose objective is to realize periodical orbits from chaotic states. The concrete pinning control nodes corresponding to the subsystems of regulating the inflows from the on-ramps to the mainline were obtained and the parameters of the controller were optimized by using the stability theory of complex networks to ensure the network synchronization. The validity of the proposed coordinated chaos control method was proven via the simulation experiment. The results of the examples indicated that the order motion on urban expressway can be realized, the wide-moving traffic jam can be suppressed, and the operating efficiency is superior to that of the traditional control methods.

关键词： pinning synchronization of complex networks multi-on-ramp metering of urban expressway chaos control delayed feedback control (DFC)

An anisotropic micromechanics model for predicting the rafting direction in Ni-based single crystal superalloys

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2016年第1期32卷 135-143页

作者： Shuang-yu Li Wen-Ping Wu ming-Xiang Chen Department of Engineering Mechanics School of Civil Engineering Wuhan University State Key Laboratory of Water Resources & Hydropower Engineering Science Wuhan University

An anisotropic micromechanics model based on the equivalent inclusion method is developed to investigate the rafting direction of Ni-based single crystal *** micromechanical model considers actual cubic structure and orthogonal anisotropy properties. The von Mises stress,elastic strain energy density, and hydrostatic pressure in different inclusions of micromechanical model are calculated when applying a tensile or compressive loading along the[001] direction. The calculated results can successfully predict the rafting direction for alloys exhibiting a positive or a negative mismatch, which are in agreement with pervious experimental and theoretical studies. Moreover, the elastic constant differences and mismatch degree of the matrix and precipitate phases and their influences on the rafting direction are carefully discussed.

关键词： Ni-based single crystal superalloys Rafting Equivalent inclusion theory Stroh formalism