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佛山顺德区某大厦结构检测鉴定
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作者 谢晓锋 邓来富 《广东土木与建筑》 2008年第5期58-59,共2页
对某大厦外凸弧形外墙的底部水平裂缝进行检测和鉴定,指出裂缝是因墙体顶部未设置有效约束,墙体受到热胀冷缩引起的向外推力作用而导致,同时对加建的钢屋架和钻孔灌注桩等进行检测,为类似工程提供参考。
关键词 外凸弧形外墙 水平裂缝 结构检测
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基于信用度机制的移动延迟容忍传感网中继传输优化算法 被引量:1
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作者 王金翔 王恒 谢娅娅 《传感技术学报》 CAS CSCD 北大核心 2023年第8期1281-1289,共9页
为改善移动延迟容忍传感网(MD⁃TSN)的网络传输能力,提出了基于信用度机制的移动延迟容忍传感网传输优化算法。引入副本机制,设计了鉴权信息结构,将源节点与目的节点之间的链路连通程度及身份信息进行量化解析,以提升网络对中继链路的评... 为改善移动延迟容忍传感网(MD⁃TSN)的网络传输能力,提出了基于信用度机制的移动延迟容忍传感网传输优化算法。引入副本机制,设计了鉴权信息结构,将源节点与目的节点之间的链路连通程度及身份信息进行量化解析,以提升网络对中继链路的评估能力。采用双线性映射来构建注册鉴权密钥,以此设计了基于身份鉴权机制的中继节点可信度确认机制,通过结合哈希映射对中继节点进行身份鉴权,以降低中继节点的离线率,有效提高所选链路及中继节点的稳定性能。随后,基于信用分级评估模式,采取一级信用值、次级信用值筛选服务能力较强的中继节点作为备选节点,构建了基于信用度机制的节点激励方法,激励具有较强服务能力的节点,惩罚存在拒绝服务行为的中继节点,以进一步优化源节点与目的节点间链路,增强中继节点对源节点的服务覆盖能力。仿真实验表明,与当前常用的基于能量多跳路由机制的传感网传输算法和基于模糊-猫群优化机制的无线传感网多径传输算法相比,所提算法具有更高的网络传输带宽,以及更低的路径抖动频次和中继节点离线率。 展开更多
关键词 移动延迟容忍传感网 权信息结构 双线性映射 信用分级评估 服务覆盖
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黄藤化学成分的研究 被引量:5
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作者 扶教龙 谭昌恒 +2 位作者 黄骥 邱业先 朱大元 《江苏农业科学》 CSCD 北大核心 2009年第6期258-260,共3页
应用硅胶柱层析和凝胶柱层析方法对黄藤(Fibraurea recisaPierre)的化学成分进行分离纯化,利用现代波谱技术(MS、NMR等)对得到的化合物进行结构鉴定。结果分离得到9个化合物,分别鉴定为β-谷甾醇(β-sitoster-ol)(1)、蒲公英赛... 应用硅胶柱层析和凝胶柱层析方法对黄藤(Fibraurea recisaPierre)的化学成分进行分离纯化,利用现代波谱技术(MS、NMR等)对得到的化合物进行结构鉴定。结果分离得到9个化合物,分别鉴定为β-谷甾醇(β-sitoster-ol)(1)、蒲公英赛醇(taraxerol)(2)、松柏醛(coniferaldehyde)(3)、芥子醛(sinapaldehyde)(4)、ligballinol(5)、(+)-松脂醇[(+)-pinoresinol](6)、(+)-1羟基松脂醇[(+)-1-hydroxypinoresinol(7)]、去氧黄藤苦素(fibleucin)(8)和黄藤内酯(fibraurin)(9)。化合物1~7为首次从该植物中分离得到。 展开更多
关键词 黄藤 化学成分 结构鉴 分离
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Chemical Constituents from Roots of Semiaquilegia adoxoides 被引量:12
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作者 牛锋 谢光波 +2 位作者 崔征 陈发奎 屠鹏飞 《Journal of Chinese Pharmaceutical Sciences》 CAS 2006年第4期251-254,共4页
Semiaquilegia adoxoides ( DC. ) Makino ( Chinese name ''Tian-Kui-Zi'' ) , theonly species of genus Semiaquilegia, belongs to the Ranunculaceae family. As a perennial herbaceousplant, both the aerial pa... Semiaquilegia adoxoides ( DC. ) Makino ( Chinese name ''Tian-Kui-Zi'' ) , theonly species of genus Semiaquilegia, belongs to the Ranunculaceae family. As a perennial herbaceousplant, both the aerial parts and the roots are used in traditional Chinese medicine for differentmedications. The roots are often used to treat inflammation, snake bite, bruises and injuries,tonsillitis, mastitis, scrofula, and cancer for their antibacterial, anti-inflammatory, andantineoplastic activities. The aerial parts are used for the treatment of mastitis, bruises, andheart diseases, such as endomyocarditis. The medicinal usage of this plant prompted us toinvestigate its chemical constituents. As a result, nine compounds 1-9 ( see Figure 1) were isolatedfrom the roots of S. adoxoides. Among them, compounds 1-7 and 9 were isolated from the genusSemiaquilegia for the first time. 展开更多
关键词 Semiaquilegia adoxoides chemical constituents structure determination
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Flavanoids from Clematis hexapetala 被引量:14
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作者 董彩霞 武可泗 +1 位作者 史社坡 屠鹏飞 《Journal of Chinese Pharmaceutical Sciences》 CAS 2006年第1期15-20,共6页
Aim To study the chemical constituents from the roots and rhizomes of Clematis hexapetala Pall.. Methods The components were isolated by means of solvent extraction, repeated chromatography with silica gel, sephadex L... Aim To study the chemical constituents from the roots and rhizomes of Clematis hexapetala Pall.. Methods The components were isolated by means of solvent extraction, repeated chromatography with silica gel, sephadex LH-20 and prep-HPLC. The structures were determined by spectrum analysis. Results Twelve flavonoids were isolated and their structures were identified as 3, 5, 6, 7, 8, 3', 4'-heptamethoxyflavone (1), nobiletin (2), liquiritigenin (3), hesperetin (4), naringenin (5), liquiritigen-7-O-β-D-glucopyranoside (6), 5,7, 4' -trihydroxy-3'- methoxyflavanone -7-O-α-L-rhamnopyranosyl ( 1→6 ) -β-D-glucopyranoside (7), 6-hydroxybiochain A ( 8), formononetin (9), daidzein (10), genistein (11), and tectoridin (12). Conclusion All the said compounds were isolated from the plant for the first time. 展开更多
关键词 Clematis hexapetala Pall. FLAVONOIDS structure determination
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Saikosaponin q-1 from Bupleurum chinense 被引量:10
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作者 梁鸿 韩紫岩 +4 位作者 赵玉英 王邠 崔育新 杨文修 余奕 《Acta Botanica Sinica》 CSCD 2001年第2期198-200,共3页
A new saikosaponin was isolated from Bupleurum chinense DC., and its structure was identified as 3β,16α,23,28,30_pentahydroxy_olean_11,13(18)_dien_3_O_β_D_glucopyranosyl(1→6)_[α_L_rhamnopyranosyl (1→4)]_β_D... A new saikosaponin was isolated from Bupleurum chinense DC., and its structure was identified as 3β,16α,23,28,30_pentahydroxy_olean_11,13(18)_dien_3_O_β_D_glucopyranosyl(1→6)_[α_L_rhamnopyranosyl (1→4)]_β_D_glucopyranoside on the basis of chemical and spectral evidence, named as saikosaponin q_1. In addition, two known saikosaponins, 3″_O_acetyl_saikosaponin d and 3″_O_acetyl_saikosaponin b 2, were also isolated and identified from this plant for the first time. 展开更多
关键词 Bupleurum chinense saikosaponin q_1
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Structure Determination of Inflasaponin Ⅱ and Ⅵ fromGlycyrrhiza inflata Root 被引量:1
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作者 邹坤 赵玉英 张如意 《Journal of Chinese Pharmaceutical Sciences》 CAS 1995年第3期113-117,共5页
Seven triterpenoid saponins were isolated from the 10% EtOH extract of the root of Glycyrrhiza inflata Bat. On the basis of chemical and spectroscopic methods,two of them were identified as glycyrrhetic acid-3-O-β-... Seven triterpenoid saponins were isolated from the 10% EtOH extract of the root of Glycyrrhiza inflata Bat. On the basis of chemical and spectroscopic methods,two of them were identified as glycyrrhetic acid-3-O-β-D-6”-ethyl-glucuronopyranosyl-(1→2)-β-D-6’-n-butyl-glucuro-nopyranoside(1),and glycyrrhetic acid-3-O-β-D-6”-n-butyl-glucuronopyranosyl-(1→2)-β-D-6’-n-ethyl-glucuronopyranoside(2). Both are new compounds and named inflasaponins Ⅱ and Ⅵ respec-tively. 展开更多
关键词 Glycyrrhiza inflata Inflasaponin Inflasaponin
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Structure identification for compound I separated and purified from taxoids-produced endophytic fungi (Alternaria. alternata var. taxi 1011)
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作者 项勇 刘君 +1 位作者 呂安国 崔京霞 《Journal of Forestry Research》 SCIE CAS CSCD 2003年第3期217-220,共4页
Endophytic fungi are widely found in almost all kinds of plants. Many endophytic fungi can produce some physio-logical active compounds, which are same to or analog to those isolated from their hosts. Producing physio... Endophytic fungi are widely found in almost all kinds of plants. Many endophytic fungi can produce some physio-logical active compounds, which are same to or analog to those isolated from their hosts. Producing physiological active com-pounds through microbial fermentation can give a new way to resolve resource limitation and to find out alternative source. Through the methods of organic solvent extraction, thin layer chromatography (TLC) and column chromatography, compound I was isolated, purified from the liquid fermentation metabolites of the taxoids-produced endophytic fungi (Alternaria. alternata var. taxi 1011 Y. Xiang et LU An-guo) that was screened from the bark of Taxus. cuspidata Sieb.et Zucc.. Compound I was identified as one kind of taxoids type III, based on the analyzing results by using the methods of ultraviolet spectroscopy (UV), infrared spectroscopy (IR), mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR). This study provides a com-pleted method for separation and purification of the endophytic fungi as well as structure identification of its fermentation me-tabolite 展开更多
关键词 Alternaria. Alternata var. taxi 1011 TAXOIDS Separation Purification Structure identification
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Investigation on Chemical Components of Higher Fungus Phellinus rhabarbarinus(Berk.) G. Cunn.
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作者 胡栋宝 周北斗 《Agricultural Science & Technology》 CAS 2016年第9期1990-1992,共3页
Five compounds including 2 benzene derivatives, 2 terpenoids and 1 sterol were separated by various separation methods such as positive silica gel, Sephadex LH-20 and Rp-18 gel from higher fungi Phellinus rhabarbarin... Five compounds including 2 benzene derivatives, 2 terpenoids and 1 sterol were separated by various separation methods such as positive silica gel, Sephadex LH-20 and Rp-18 gel from higher fungi Phellinus rhabarbarinus (Berk.) G. Cunn. Their structures were elucidated on the basis of nuclear magnetic resonance (NMR) spectroscopy and other methods. All the compounds were separated from this higher fungus for the first time. 展开更多
关键词 Phellinus rhabarbarinus (Berk.) G. Cunn. Chemical component Structural identification
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Structure Determination of By-product in Grignard Reaction for Preparing Mifepristone Derivatives 被引量:1
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作者 陈安平 雷小平 《Journal of Chinese Pharmaceutical Sciences》 CAS 2004年第1期19-23,共5页
Aim To determine the structure of the by-product produced in Grignard reaction for preparing mifepristone derivatives, and elucidate the reaction mechanism.Methods The structure of the by-product was determined with e... Aim To determine the structure of the by-product produced in Grignard reaction for preparing mifepristone derivatives, and elucidate the reaction mechanism.Methods The structure of the by-product was determined with elemental analysis, one- and two-dimension spectra NMR (DEPT, 1H-1Hcosy, HMQC, HMBC) and compared with those of mifepristone.Results The main by-product was 11,17-di-addition product of Grignard reagent of N, N-dimethylamino phenyl bromide.Conclusion This is the first complete assignment of 1H NMR and 13C NMR of compound (3). 展开更多
关键词 by-product identification mifepristone derivatives two-dimension NMR
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Preparation of Conjugated Linoleic Acid and Identification of Its Isomers 被引量:9
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作者 郭诤 张根旺 孙彦 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第2期130-135,共6页
Conjugated linoleic acid (CLA) is a kind of fatty acid with physiological activities and potential application prospect. A synthesis method of conjugated linoleic acid and a purification technology were studied. CLA w... Conjugated linoleic acid (CLA) is a kind of fatty acid with physiological activities and potential application prospect. A synthesis method of conjugated linoleic acid and a purification technology were studied. CLA was prepared and purified by urea-complexation and conjugation using safflower oil as raw material. The purity of CLA and total recovery of the product was more than 95% and 48%, respectively. The main isomers produced in alkali-catalyzed conjugation were identified by gas chromatography (GC) linked to mass spectrometry (MS) and Fourier transform infrared spectroscopy (FTIR). The total amount of the two main isomers (9cis, 11trons-and 10trans, 12cis-CLA) determined by GC was more than 90% of the product. 展开更多
关键词 linoleic acid conjugated linoleic acid urea-complexation alkali-catalyzed conjugation IDENTIFICATION safflower oil
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Analysis of phospholipids in microalga Nitzschia closterium by UPLC-Q-TOF-MS 被引量:6
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作者 严小军 李海英 +1 位作者 徐继林 周成旭 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第1期106-112,共7页
Precise structural identification of phospholipids in the microalga Nitzschia closterium has been established using ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectr... Precise structural identification of phospholipids in the microalga Nitzschia closterium has been established using ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (UPLC-ESI-Q-TOF-MS) for direct analysis of total lipid extracts.Mass spectrometry was performed in reflective time-of-flight using electron spraying ionization in negative mode.Phospholipid molecular species identification was based on the characteristic product ions and neutral loss yielded by different phospholipids under ESI-MS/MS mode.The molecular species were confirmed by the carboxylate anions produced by phospholipids in negative mode;the regiospecificity of the two acyl chains was determined from the ratio of sn-1 to sn-2 carboxylate anion abundances.As a result,18 lipid molecular species were identified for the first time in this microalga,comprising seven phosphatidylcholines (PC),two phosphatidylethanolamines (PE),two phosphatidylinositols (PI),and seven phosphatidylglycerols (PG).Lipid standards of PC,PE,PI,and PG were added to the total lipids as internal standards for semiquantitative analysis,revealing concentrations of phospholipids in this species between 0.09 and 3.37 nmol/mg.This method can produce a full structural profile of intact phospholipid molecular species and can be used for study of the physiological and ecological functions of lipids by monitoring their individual changes over time. 展开更多
关键词 Nitzschia closterium PHOSPHOLIPIDS UPLC-Q-TOF-MS
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Expression and Identification of Inclusion Forming-related Domain of NS80 Nonstructural Protein of Grass Carp Reovirus 被引量:4
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作者 Chao FAN Lan-lan ZHANG +1 位作者 Cheng-feng LEI Qin FANG 《Virologica Sinica》 SCIE CAS CSCD 2009年第3期194-201,共8页
Grass carp reovirus (GCRV), a double stranded RNA virus that infects aquatic animals, often with disastrous effects, belongs to the genus Aquareovirus and family Reoviridea. Similar to other reoviruses, genome repli... Grass carp reovirus (GCRV), a double stranded RNA virus that infects aquatic animals, often with disastrous effects, belongs to the genus Aquareovirus and family Reoviridea. Similar to other reoviruses, genome replication of GCRV in infected cells occurs in cytoplasmic inclusion bodies, also called viral factories. Sequences analysis revealed the nonstmctural protein NS80, encoded by GCRV segment 4, has a high similarity with μNS in MRV(Mammalian orthoreovimses), which may be associated with viral factory formation. To understand the function of the μNS80 protein in virus replication, the initial expression and identification of the immunogenicity of the GCRV NS80 protein inclusion forming-related region (335-742) was investigated in this study. It is shown that the over-expressed fusion protein was produced by inducing with IPTG at 28℃. In addition, serum specific rabbit antibody was obtained by using super purified recombinant NS80(335-742) protein as antigen. Moreover, the expressed protein was able to bind to anti-his-tag monoclonal antibody (mouse) and NS80〈335.742) specific rabbit antibody. Further western blot analysis indicates that the antiserum could detect NS80 or NS80C protein expression in GCRV infected cells. This data provides a foundation for further investigation of the role of NS80 in viral inclusion formation and virion assembly. 展开更多
关键词 Grass carp reovims (GCRV) Nonstmctural protein NS80 Inclusion forming-related domain Recombinant expression
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Structural damage identification using test static data based on grey system theory 被引量:4
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作者 陈孝珍 朱宏平 陈传尧 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第8期790-796,共7页
A new structural damage identification method using limited test static displacement based on grey system theory is proposed in this paper. The grey relation coefficient of displacement curvature is defined and used t... A new structural damage identification method using limited test static displacement based on grey system theory is proposed in this paper. The grey relation coefficient of displacement curvature is defined and used to locate damage in the structure, and an iterative estimation scheme for solving nonlinear optimization programming problems based on the quadratic programming technique is used to identify the damage magnitude. A numerical example of a cantilever beam with single or multiple damages is used to examine the capability of the proposed grey-theory-based method to localize and identify damages. The factors of meas-urement noise and incomplete test data are also discussed. The numerical results showed that the damage in the structure can be localized correctly through using the grey-related coefficient of displacement curvature, and the damage magnitude can be iden-tified with a high degree of accuracy, regardless of the number of measured displacement nodes. This proposed method only requires limited static test data, which is easily available in practice, and has wide applications in structural damage detection. 展开更多
关键词 Damage identification Grey relation coefficient Static test data
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Hazard degree identification of goafs based on scale effect of structure by RS-TOPSIS method 被引量:6
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作者 胡建华 尚俊龙 +4 位作者 周科平 陈宜楷 甯榆林 刘浪 Mohammed M.Aliyu 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期684-692,共9页
In order to precisely predict the hazard degree of goaf(HDG), the RS-TOPSIS model was built based on the results of expert investigation. To evaluate the HDG in the underground mine, five structure size factors, i.e. ... In order to precisely predict the hazard degree of goaf(HDG), the RS-TOPSIS model was built based on the results of expert investigation. To evaluate the HDG in the underground mine, five structure size factors, i.e. goaf span, exposed area, goaf height, goaf depth, and pillar width, were selected as the evaluation indexes. And based on rough dependability in rough set(RS)theory, the weights of evaluation indexes were identified by calculating rough dependability between evaluation indexes and evaluation results. Fourty goafs in some mines of western China, whose indexes parameters were measured by cavity monitoring system(CMS), were taken as evaluation objects. In addition, the characteristic parameters of five grades' typical goafs were built according to the interval limits value of single index evaluation. Then, using the technique for order preference by similarity to ideal solution(TOPSIS), five-category classification of HDG was realized based on closeness degree, and the HDG was also identified.Results show that the five-category identification of mine goafs could be realized by RS-TOPSIS method, based on the structure-scale-effect. The classification results are consistent with those of numerical simulation based on stress and displacement,while the coincidence rate is up to 92.5%. Furthermore, the results are more conservative to safety evaluation than numerical simulation, thus demonstrating that the proposed method is more easier, reasonable and more definite for HDG identification. 展开更多
关键词 GOAF RS-TOPSIS method hazard degree scale effect
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Molecular cloning and characterization of SoxB2 gene from Zhikong scallop Chlamys farreri 被引量:1
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作者 贺艳 包振民 +5 位作者 郭慧慧 张月月 张玲玲 王师 胡景杰 胡晓丽 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第6期1216-1225,共10页
The Sox proteins play critical roles during the development of animals, including sex determination and central nervous system development. In this study, the SoxB2 gene was cloned from a mollusk, the Zhikong scallop ... The Sox proteins play critical roles during the development of animals, including sex determination and central nervous system development. In this study, the SoxB2 gene was cloned from a mollusk, the Zhikong scallop (Chlamysfarreri), and characterized with respect to phylogeny and tissue distribution. The full-length cDNA and genomic DNA sequences of C. farreri SoxB2 (CflSoxB2) were obtained by rapid amplification of cDNA ends and genome walking, respectively, using a partial cDNA fragment from the highly conserved DNA-binding domain, i.e., the High Mobility Group (HMG) box. The full-length cDNA sequence of CJSoxB2 was 2 048 bp and encoded 268 amino acids protein. The genomic sequence was 5 551 bp in length with only one exon. Several conserved elements, such as the TATA-box, GC-box, CAAT-box, GATA-box, and Sox/sry-sex/testis-determining and related HMG box factors, were found in the promoter region. Furthermore, real-time quantitative reverse transcription PCR assays were carried out to assess the mRNA expression of CJSoxB2 in different tissues. SoxB2 was highly expressed in the mantle, moderately in the digestive gland and gill, and weakly expressed in the gonad, kidney and adductor muscle. In male and female gonads at different developmental stages of reproduction, the expression levels of CfS;oxB2 were similar. Considering the specific expression and roles of SoxB2 in other animals, in particular vertebrates, and the fact that there are many pallial nerves in the mantle, cerebral ganglia in the digestive gland and gill nerves in gill, we propose a possible essential role in nervous tissue function for SoxB2 in C.farreri. 展开更多
关键词 SoxB2 gene organization PROMOTER QRT-PCR Chlamysfarreri
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Research on the Seismotectonic Setting in Beibu Gulf Waters 被引量:1
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作者 Li Jinchen Pan Hua Chen Wenbin 《Earthquake Research in China》 2010年第2期263-271,共9页
In this paper we discuss the seismogenic structures of the two earthquakes occurring in the Beibu Gulf waters,based on the investigation of geological structure,faults,geophysical fields,seismicity and earthquake foca... In this paper we discuss the seismogenic structures of the two earthquakes occurring in the Beibu Gulf waters,based on the investigation of geological structure,faults,geophysical fields,seismicity and earthquake focal mechanism.The results show that the NEE trending faults along the boundary of the Wushi depression are the dominating seismogenic structures,and the NW trending faults are the key factors of stress concentration.The results also show that high seismicity has a significant relationship with the late Cenozoic deposition center in the Beibu Gulf,and their NE-NEE trending boundary faults are important to the identification of seismogenic structures.The special arcuate fault segment or the intersection point of the NW trending faults and NE-NEE trending boundary faults is a possible location of future earthquakes. 展开更多
关键词 Beibu Gulf Double-shock type earthquake Seismogenic structure Wushi depression Haizhong depression
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Isolation and structural identification of two bioactive phenazines from Streptomyces griseoluteus P510
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作者 罗勤 胡洪波 +2 位作者 彭华松 张雪洪 王威 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第4期699-703,共5页
Phenazine antibiotics phenazine-l-carboxylic acid (PCA) and l-hydroxyphenazine (1-OH-PHZ) were purified from culture broth and mycelia ofStreptomyces griseoluteus P510, Both PCA and 1 -OH-PHZ exhibit strong antifu... Phenazine antibiotics phenazine-l-carboxylic acid (PCA) and l-hydroxyphenazine (1-OH-PHZ) were purified from culture broth and mycelia ofStreptomyces griseoluteus P510, Both PCA and 1 -OH-PHZ exhibit strong antifun- gal activity against six plant pathogens, especially Fusarium oxysporium, with minimal inhibition concentrations less than I and 2/ag, ml- 1 for PCA and 1-OH-PHZ, respectively, The presence of PCA and 1 -OH-PHZ indicates that S. griseoluteus PSlO can be used as a potential source of pesticides, 展开更多
关键词 Streptomyces griseoluteus P510Phenazine antibioticPhenazine-1-carboxylic acidl-Hydroxyphenazine
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Extraction and Structure Elucidation of Phenols from Dendrobium thyrsiflorum
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作者 Ruixuan WENG Yupeng LI +5 位作者 Shuang LI Guihua ZHANG Ying WANG Xiaoling WEN Jun ZHANG Rong HUANG 《Agricultural Science & Technology》 CAS 2015年第10期2144-2145,共2页
[Objective] This study aimed to investigate the chemical constituents of Dendrobium thyrsiflorum and determine its bioactive compounds. [Method] The compounds were extracted by 95% alcohol and isolated by column chrom... [Objective] This study aimed to investigate the chemical constituents of Dendrobium thyrsiflorum and determine its bioactive compounds. [Method] The compounds were extracted by 95% alcohol and isolated by column chromatography on silica gel and Sephadex LH-20. Their structures were identified by spectroscopic analysis(1H NMR and13 C NMR). [Result] Seven compounds were obtained and identified as 4, 7-dihydroxy-2-methoxy-9, 10-dihydrophenan-threne(1), syringaldehyde(2),moscatin(3), gigantol(4), batatasin III(5), tristin(6) and stigmasterol(7). [Conclusion] Compounds 1 and 2 were isolated from this medicinal plant for the first time. 展开更多
关键词 Dendrobium medicinal dihydroxy methoxy silica bioactive aimed alcohol spectroscopic Seven
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Identification of structural entities in NdF_3-LiF melts with cryoscopic method 被引量:4
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作者 胡宪伟 王兆文 +3 位作者 高炳亮 石忠宁 刘凤国 包莫日根高娃 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第12期2387-2391,共5页
Nd-F species in NdF3-LiF melts were studied using cryoscopic method.Liquidus temperatures of melts of various compositions were determined by differential thermal analysis(DTA).Based on the different model calculation... Nd-F species in NdF3-LiF melts were studied using cryoscopic method.Liquidus temperatures of melts of various compositions were determined by differential thermal analysis(DTA).Based on the different model calculations,NdF4- was identified as the most likely Nd-F entity in the melts in which the mole fraction of NdF3 was lower than 20%,considering only one single Nd species in the melt,and which was formed in accordance with Temkin model or Flood model.Then,activities of different components in the melts were researched.The results show that activity of LiF decreases,and that of NdF3 increases with increasing the mole fraction of NdF3.The value of activity coefficient of NdF3 is higher than 1,and that of LiF is lower than 1. 展开更多
关键词 structural entities NdF3-LiF melts cryoscopic method liquidus temperature
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