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A new triterpenoid saponin from the leaves and stems of Panax quinquefolium L.

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Chinese Chemical Letters 2009年第10期20卷 1207-1210页

作者： Guo Yu li Yi Mei Zeng He Meng xian li Jin Hui Wang School of Pharmacy Shihezi University Shihezi 832002 China School of Traditional Chinese Materia Medica. Shenyang Pharmaceutical University Shenyang 110016 China

One new triterpcnoid saponin, quinquenoside L17 （1）, was isolated from the leaves and stems of Panax quinquefolium L., and its structure was elucidated as 20-O-[（β-D-xylopyranosyl-（1-6）-O-β-D-glucopyranosy）]-6-O-β-D-glucopyranosy1-dammar-24-ene- 3,6,12,20-tetraol, by the combination analysis of one-dimensional NMR and two-dimensional NMR, mass spectrometry, CD spectrum and chemical evidences.

关键词： Panax quinquefolium L. Quinquenoside L17 Triterpenoid saponin

Parametric message passing-based relative navigation in joint tactical information distribution system

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Journal of Systems Engineering and Electronics 2016年第1期27卷 81-89页

作者： Nan Wu bin li Hua Wang liang Hou Jingming Kuang School of Information and Electronics Beijing Institute of Technology

Relative navigation is a key feature in the joint tactical information distribution system（JTIDS）.A parametric message passing algorithm based on factor graph is proposed to perform relative navigation in *** of all,the joint posterior distribution of all the terminals＇ positions is represented by factor *** of the nonlinearity between the positions and time-of-arrival（TOA） measurement,messages cannot be obtained in closed forms by directly using the sum-product algorithm on factor *** this end,the Euclidean norm is approximated by Taylor ***,all the messages on the factor graph can be derived in Gaussian forms,which enables the terminals to transmit means and ***,the impact of major error sources on the navigation performance are evaluated by Monte Carlo simulations,e.g.,range measurement noise,priors of position uncertainty and velocity *** show that the proposed algorithm outperforms the extended Kalman filter and cooperative extended Kalman filter in both static and mobile scenarios of the JTIDS.

关键词： joint tactical information distribution system(JTIDS) relative navigation parametric message passing factor graph.

2D-Cell Experiment on Methyl Tert-Butyl Ether Transport in Saturated Zone of Groundwater

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Chinese Geographical Science 2007年第3期17卷 275-279页

作者： li Hong li Xingang Gao Chuanbo Huang Guoqiang Jiang bin School of Chemical Engineering and Technology Tianjin UniversityTianjin300072China National Engineering Research Center for Distillation Technology Tianjin UniversityTianjin300072China

As an additive of gasoline,methyl ten-butyl ether(MTBE)has a higher solubility in water,which is about 20 times as high as that of *** characteristic results in MTBE dissolving out of the gasoline into the soil and *** to relative unique physicochemical behavior of MTBE it would be an ideal candidate for use in environmental forensic *** order to study the transport and distribution of MTBE in saturated zone of ground water,a two-dimensional experimental cell was setup to simulate the real environment of the groundwater *** effects of soil and groundwater flow velocity on the MTBE transport were *** results show that the mobile distance of MTBE in vertical direction was smaller than that in horizontal direction paralleling with the groundwater *** the main dynamics of groundwater flow direction was convection and dispersion,the movement of MTBE is also diffusion in the vertical *** addition,the transport of MTBE was more quick in high permeability porous media,and the increase of groundwater flow velocity can accelerate the MTBE plume development,but the irregularity and randomness of the plume are enhanced *** research results can give some helps for the investigation of MTBE movement in the groundwater,also can make some references for other petroleum contamination behavior.

关键词： Methyl Tert-Butyl Ether pollutant transport groundwater 2D-sandbox

Design,synthesis and preliminary bio-evaluation of glucose-cholesterol derivatives as ligands for brain targeting liposomes

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Chinese Chemical Letters 2011年第7期22卷 831-834页

作者： Fan Lei Wei Fan xian Kun li Shan Wang li Hai Yong Wu Key Laboratory of Drug Targeting and Drug Delivery Systems West China School of Pharmacy Sichuan University Chengdu 610041 China

A series of glucose-cholesterol derivatives 8a-8e as ligands for brain targeting liposomes were synthesized. The preparation of compound 6 involved temporary protection of glucose with chlorotrimethylsilicane and hexamethyldisilazane followed by selectively hydrolyzed. The known cholesteryl tosylate 1 were coupled to ethylene glycols to afford alcohol 2a-2e. Substitution and deprotection of alcohol 2a-2e furnished the acids 4a-4e, which was condensed with compound 6 to get compounds 7a-7e, and then was deprotected in tetrahydrofuran with TFA to obtain the title compounds. As a model drug, tegafur was entrapped by liposomes coupled with 8b, and preliminary in vivo evaluation shown 8b could enhance the ability of liposomes delivering tegafur across the blood brain barrier.

关键词： liposome ligands Brain target GLUTt transporter Tegafur Synthesis

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坡度X70管线钢全自动外焊接头组织与性能

中国石油大学学报（自然科学版） 2024年第3期48卷 145-153页

作者：韩彬高建章周聪贾彦杰刘雪光谢斐牛盛源李立英中国石油大学(华东)材料科学与工程学院山东青岛266580 国家管网集团西南管道有限责任公司四川成都610095 海洋石油工程股份有限公司天津300461

采用全自动外焊工艺对坡度为25°的X70管线钢进行焊接,利用光学显微镜和背散射电子衍射(EBSD)对焊接接头组织进行观察,并对焊接接头进行拉伸、弯曲、硬度、冲击和裂纹尖端张开位移(CTOD)等试验。结果表明:上下坡口的粗晶区宽度和焊接残... 详细信息

采用全自动外焊工艺对坡度为25°的X70管线钢进行焊接,利用光学显微镜和背散射电子衍射(EBSD)对焊接接头组织进行观察,并对焊接接头进行拉伸、弯曲、硬度、冲击和裂纹尖端张开位移(CTOD)等试验。结果表明:上下坡口的粗晶区宽度和焊接残余应力不同,上坡口粗晶区宽、残余应力大;焊接位置明显影响内表面熔合线冲击功,平焊和立焊位置内表面熔合线冲击功远低于仰焊位置,是接头的韧性薄弱区;焊缝冲击功较高而CTOD值较低,建议评定焊接接头韧性应同时考虑冲击功和CTOD值;根焊区是焊接接头的危险区,易引起环焊缝失效,建议采用等强或高强匹配,焊接工艺评定应区分山区和平原地区,对山区条件下接头进行焊接工艺评定时一定要重点关注根焊区。

关键词：大坡度 X70管线钢全自动焊显微组织韧性

维普期刊数据库博看期刊

硫化氢调控酚类化合物代谢缓解番茄盐胁迫的作用机制

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植物生理学报 2024年第3期60卷 518-528页

作者：王维轩李世洁梁继杰王秦政苏畅高克明李宗明吕昊峰梁斌周伟伟青岛农业大学资源与环境学院山东青岛266109

盐胁迫是限制作物产量形成的重要环境障碍因子之一。本试验以番茄为供试材料,探究了外源不同浓度(50、100、200和500μmol L^(-1))的硫化氢(H_(2)S)供体硫氢化钠(NaHS)对盐胁迫下番茄生长和生理特性的影响,同时对酚类化合物代谢及其与... 详细信息

盐胁迫是限制作物产量形成的重要环境障碍因子之一。本试验以番茄为供试材料,探究了外源不同浓度(50、100、200和500μmol L^(-1))的硫化氢(H_(2)S)供体硫氢化钠(NaHS)对盐胁迫下番茄生长和生理特性的影响,同时对酚类化合物代谢及其与耐盐性的关系进行了探究。结果表明,适宜浓度的H_(2)S处理显著提高盐胁迫下番茄株高、茎粗、地上部鲜重和干重、根鲜重和根长,以及叶绿素和类胡萝卜素含量,有效缓解盐胁迫对番茄生长的抑制。外源H_(2)S显著降低盐胁迫下番茄活性氧(ROS)的积累和丙二醛(MDA)含量,这与其较高的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性以及可溶性蛋白、可溶性糖和脯氨酸等渗透调节物质积累密切相关。此外,外源H_(2)S可显著提高盐胁迫下番茄总酚、类黄酮和花色素苷含量及其抗氧化活性,而外源多酚合成抑制剂AIP处理则显著降低酚类化合物的积累,同时显著降低H_(2)S对盐胁迫下番茄氧化损伤的缓解作用。本研究阐明了H_(2)S提高番茄耐盐胁迫作用机制,证实了H_(2)S诱导酚类化合物积累在番茄耐盐胁迫中的作用机制,为番茄耐盐品种的选育和遗传改良提供了新思路。

关键词：番茄盐胁迫硫化氢酚类化合物抗氧化系统

Anionic polymerization of fluorine-substituted phenyl methacrylates

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Science China Chemistry 2015年第1期58卷 107-113页

作者： bin li Pan Zhou Yuefei Chen Biao Jiang Hongping Zhu State Key Laboratory of Physical Chemistry of Solid Surfaces National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters College of Chemistry and Chemical Engineering Xiamen University

Synthesis and anionic polymerization of the fluorine-substituted phenyl methacrylates are herein reported. A series of monodi-, and multi-substituted fluorophenyl methacrylates H2C=C（CH3）C（O）OC6H4F-4 （M^1a）, H2C=C（CH3）C（O）OC6H4F-3 （M^1b）, HEC=C（CH3）C（O）OC6H3F2-2,4 （M^2）, H2C=C（CH3）C（O）OC6H2F3-2,3,4 （M^3）, H2C=C（CH3）C（O）OC6HF4-2,3,5,6 （M^4）, and H2C=C（CH3）C（O）OC6F5 （M^5） were synthesized and characterized. Initially, the polymerization was carded out on the monomer M^1a by using nBuli, tBuli, and KH as the respective catalysts; this approach produced the polymers in yields of 12%-50%, but with lower molecular weights. Similar results were obtained by using tBuli for catalytically polymerizing the other five monomers. By introducing a co-catalyst MeAl（BHT）2, the catalysts Nail, liH, and tBuOli each were tested to polymerize M^1a, which gave the polymers in very low yields （3%-7%）. Polymer yields of 13%-27% were obtained by each of the catalysts liAlH4, nBuli, Phli, and tBuli in connection with MeAI（BHT）2, but a better yield （61%） was achieved with KH/MeAl（BHT）2. The KH/MeAl（BHT）2 catalyst system was further employed to polymerize M^1b and M^2, which afforded respective polymer yields of 12%-63% and 10%-53%, depending on the molar ratios of KH：MeAl（BHT）2 as well as on the monomer concentrations. All of the polymers produced were syndiotactically rich in structure, as indicated by either ^1H or ^19F NMR data. The polymerization mechanism by the combined catalyst system is proposed.

关键词： fluorophenyl methacrylates the combined catalyst system anionic polymerization syndiotactic polymer,^1H and ^19F NMR data

Facile Synthesis,Characterization of Flower-like Vanadium Pentoxide Powders and Their Photocatalytic Behavior

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Acta Metallurgica Sinica(English Letters) 2017年第10期30卷 1017-1026页

作者： Yao li Jian-Lei Kuang Yi Lu Wen-bin Cao Department of Inorganic Nonmetallic Materials School of Materials Science and EngineeringUniversity of Science and Technology Beijing The 306 Hospital of PLA Tianjin College University of Science and Technology Beijing

In this paper, V2O5 sol was firstly prepared using vanadyl sulfate as a vanadium source by modified sol-gel method at room temperature. Then flower-like V2O5 powders were prepared by coagulating as-prepared sol with anhydrous ethanol and subsequent annealing crystallization. The X-ray diffraction analysis indicated that V2O5 powders exhibited orthorhombic crystal structure after annealing at 450 ℃. The experimental data obtained from both field emission scanning electron microscopy and high-resolution transmission electron microscopy identified that V2O5 powders were approximately flower-like in shape and about 5 μm in size. Besides, the Brunauer-Emmett-Teller specific surface area of flowerlike V2O5 powders was 24.25 m^2/g. According to Uv-Vis spectroscopy, the degradation rate of toluidine blue O（TBO） on as-prepared flower-like V2O5 powders during 10 h of visible light irradiation with an intensity of 15.4 mW/m^2 was 88%,which was faster than those over P25（46%） as a comparison. In addition, the mineralization process of TBO was investigated, which primarily consisted of demethylation and ring-opening oxidation processes, and confirmed by liquid chromatograph-mass spectrometry. The precipitation-oxidation-peptization, coagulation, and crystallization processes were proposed as the formation mechanism for the preparation of flower-like V2O5.

关键词： Vanadium pentoxide Photocatalyst Toluidine Blue O Mechanism Demethylation

Near Infrared Star Centroid Detection by Area Analysis of Multi-Scale Super Pixel Saliency Fusion Map

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Tsinghua Science and Technology 2019年第3期24卷 291-300页

作者： Xiaohu Yuan Shaojun Guo Chunwen li bin Lu Shuli Lou the Department of Automation Tsinghua University the National Innovation Institute of Defense Technology Naval Aeronautical University Yantai University

The centroid location of a near infrared star always deviates from the real center due to the effects of surrounding radiation. To determine a more accurate center of a near infrared star, this paper proposes a method to detect the star's saliency area and calculate the star's centroid via the pixels only in this area, which can greatly decrease the effect of the radiation. During saliency area detection, we calculated the boundary connectivity and gray similarity of every pixel to estimate how likely it was to be a background pixel. Aiming to simplify and speed up the calculation process, we divided the near infrared starry sky image into super pixel maps at multi-scale by Simple linear Iterative Clustering(SliC). Second, we detected the saliency map for every super pixel map of the image. Finally, we fused the saliency maps according to a weighted coefficient that is determined by the least square method. For the images used in our experiment, we set the multi-scale super pixel numbers to 100, 150,and 200. The results show that our method can obtain an offset variance of less than 0.27 for the center coordinates compared to the labelled centers.

关键词： near infrared starry star saliency Simple linear Iterative Clustering (SliC)