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多体非完全经典态的基于Affinity的关联测度
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作者 闫栋华 王银珠 《太原科技大学学报》 2024年第1期101-103,108,共4页
在量子信息理论中,量子关联是一种极其重要的物理资源。文章首先定义了多体非完全经典态基于Affinity的一种量子关联测度,它可以量化多体非完全经典态的关联程度;接下来证明了该关联测度满足量子关联度的一些必要物理性质,包括非负性、... 在量子信息理论中,量子关联是一种极其重要的物理资源。文章首先定义了多体非完全经典态基于Affinity的一种量子关联测度,它可以量化多体非完全经典态的关联程度;接下来证明了该关联测度满足量子关联度的一些必要物理性质,包括非负性、局部酉操作下的不变性、局部量子操作下的单调性、凸性以及连续性。 展开更多
关键词 多体复合系统 完全经典态 投影测量 量子关联度 affinity
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Strategies for Enhancing the Affinity of College Ideological and Political Course Teachers
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作者 WANG Na 《Cultural and Religious Studies》 2024年第2期113-117,共5页
This article aims to explore effective ways to enhance the affinity of ideological and political course teachers in universities.By analyzing the connotation of affinity,the factors that affect the affinity of ideolog... This article aims to explore effective ways to enhance the affinity of ideological and political course teachers in universities.By analyzing the connotation of affinity,the factors that affect the affinity of ideological and political course teachers are analyzed,and corresponding improvement strategies are proposed.Research suggests that strengthening the construction of teacher ethics and conduct,improving teaching skills,enhancing emotional engagement,and enhancing practical training are key paths to enhance the affinity of ideological and political course teachers.The implementation of these paths will help improve the teaching quality and effectiveness of ideological and political courses,and promote the comprehensive development of students. 展开更多
关键词 ideological and political courses in universities teacher affinity improvement path teaching quality
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多体k不可分量子态基于Affinity的纠缠测度
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作者 杨丽丽 王银珠 《太原科技大学学报》 2023年第6期567-570,共4页
量子纠缠是一种重要的物理资源,已被广泛应用于量子信息及量子计算的许多领域中。提出了一种多体复合系统量子态相对于k体分划的基于Affinity的纠缠测度,并证明了其满足纠缠测度的必要物理性质。
关键词 多体量子系统 k可分性 affinity 纠缠测度
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Virtual Machine Consolidation with Multi-Step Prediction and Affinity-Aware Technique for Energy-Efficient Cloud Data Centers
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作者 Pingping Li Jiuxin Cao 《Computers, Materials & Continua》 SCIE EI 2023年第7期81-105,共25页
Virtual machine(VM)consolidation is an effective way to improve resource utilization and reduce energy consumption in cloud data centers.Most existing studies have considered VM consolidation as a bin-packing problem,... Virtual machine(VM)consolidation is an effective way to improve resource utilization and reduce energy consumption in cloud data centers.Most existing studies have considered VM consolidation as a bin-packing problem,but the current schemes commonly ignore the long-term relationship between VMs and hosts.In addition,there is a lack of long-term consideration for resource optimization in the VM consolidation,which results in unnecessary VM migration and increased energy consumption.To address these limitations,a VM consolidation method based on multi-step prediction and affinity-aware technique for energy-efficient cloud data centers(MPaAF-VMC)is proposed.The proposed method uses an improved linear regression prediction algorithm to predict the next-moment resource utilization of hosts and VMs,and obtains the stage demand of resources in the future period through multi-step prediction,which is realized by iterative prediction.Then,based on the multi-step prediction,an affinity model between the VM and host is designed using the first-order correlation coefficient and Euclidean distance.During the VM consolidation,the affinity value is used to select the migration VM and placement host.The proposed method is compared with the existing consolidation algorithms on the PlanetLab and Google cluster real workload data using the CloudSim simulation platform.Experimental results show that the proposed method can achieve significant improvement in reducing energy consumption,VM migration costs,and service level agreement(SLA)violations. 展开更多
关键词 Cloud computing VM consolidation multi-step prediction affinity relationship energy efficiency
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Secondary electron emission and photoemission from a negative electron affinity semiconductor with large mean escape depth of excited electrons
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作者 谢爱根 董红杰 刘亦凡 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期677-690,共14页
The formulae for parameters of a negative electron affinity semiconductor(NEAS)with large mean escape depth of secondary electrons A(NEASLD)are deduced.The methods for obtaining parameters such asλ,B,E_(pom)and the m... The formulae for parameters of a negative electron affinity semiconductor(NEAS)with large mean escape depth of secondary electrons A(NEASLD)are deduced.The methods for obtaining parameters such asλ,B,E_(pom)and the maximumδandδat 100.0 keV≥E_(po)≥1.0 keV of a NEASLD with the deduced formulae are presented(B is the probability that an internal secondary electron escapes into the vacuum upon reaching the emission surface of the emitter,δis the secondary electron yield,E_(po)is the incident energy of primary electrons and E_(pom)is the E_(po)corresponding to the maximumδ).The parameters obtained here are analyzed,and it can be concluded that several parameters of NEASLDs obtained by the methods presented here agree with those obtained by other authors.The relation between the secondary electron emission and photoemission from a NEAS with large mean escape depth of excited electrons is investigated,and it is concluded that the presented method of obtaining A is more accurate than that of obtaining the corresponding parameter for a NEAS with largeλ_(ph)(λ_(ph)being the mean escape depth of photoelectrons),and that the presented method of calculating B at E_(po)>10.0 keV is more widely applicable for obtaining the corresponding parameters for a NEAS with largeλ_(ph). 展开更多
关键词 negative electron affinity semiconductor secondary electron emission PHOTOEMISSION the probability secondary electron yield large mean escape depth of excited electrons
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Automatic Aggregation Enhanced Affinity Propagation Clustering Based on Mutually Exclusive Exemplar Processing
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作者 Zhihong Ouyang Lei Xue +1 位作者 Feng Ding Yongsheng Duan 《Computers, Materials & Continua》 SCIE EI 2023年第10期983-1008,共26页
Affinity propagation(AP)is a widely used exemplar-based clustering approach with superior efficiency and clustering quality.Nevertheless,a common issue with AP clustering is the presence of excessive exemplars,which l... Affinity propagation(AP)is a widely used exemplar-based clustering approach with superior efficiency and clustering quality.Nevertheless,a common issue with AP clustering is the presence of excessive exemplars,which limits its ability to perform effective aggregation.This research aims to enable AP to automatically aggregate to produce fewer and more compact clusters,without changing the similarity matrix or customizing preference parameters,as done in existing enhanced approaches.An automatic aggregation enhanced affinity propagation(AAEAP)clustering algorithm is proposed,which combines a dependable partitioning clustering approach with AP to achieve this purpose.The partitioning clustering approach generates an additional set of findings with an equivalent number of clusters whenever the clustering stabilizes and the exemplars emerge.Based on these findings,mutually exclusive exemplar detection was conducted on the current AP exemplars,and a pair of unsuitable exemplars for coexistence is recommended.The recommendation is then mapped as a novel constraint,designated mutual exclusion and aggregation.To address this limitation,a modified AP clustering model is derived and the clustering is restarted,which can result in exemplar number reduction,exemplar selection adjustment,and other data point redistribution.The clustering is ultimately completed and a smaller number of clusters are obtained by repeatedly performing automatic detection and clustering until no mutually exclusive exemplars are detected.Some standard classification data sets are adopted for experiments on AAEAP and other clustering algorithms for comparison,and many internal and external clustering evaluation indexes are used to measure the clustering performance.The findings demonstrate that the AAEAP clustering algorithm demonstrates a substantial automatic aggregation impact while maintaining good clustering quality. 展开更多
关键词 Clustering affinity propagation automatic aggregation enhanced mutually exclusive exemplars constraint
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A Deep Learning Drug-Target Binding Affinity Prediction Based on Compound Microstructure and Its Application in COVID-19 Drug Screening
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作者 Yijie Guo Xiumin Shi Han Zhou 《Journal of Beijing Institute of Technology》 EI CAS 2023年第4期396-405,共10页
Drug target relationship(DTR)prediction is a rapidly evolving area of research in com-putational drug discovery.Despite recent advances in computational solutions that have overcome the challenges of in vitro and in v... Drug target relationship(DTR)prediction is a rapidly evolving area of research in com-putational drug discovery.Despite recent advances in computational solutions that have overcome the challenges of in vitro and in vivo experiments,most computational methods still focus on binary classification.They ignore the importance of binding affinity,which correctly distinguishes between on-targets and off-targets.In this study,we propose a deep learning model based on the microstruc-ture of compounds and proteins to predict drug-target binding affinity(DTA),which utilizes topo-logical structure information of drug molecules and sequence semantic information of proteins.In this model,graph attention network(GAT)is used to capture the deep features of the compound molecular graph,and bidirectional long short-term memory(BiLSTM)network is used to extract the protein sequence features,and the pharmacological context of DTA is obtained by combining the two.The results show that the proposed model has achieved superior performance in both cor-rectly predicting the value of interaction strength and correctly discriminating the ranking of bind-ing strength compared to the state-of-the-art baselines.A case study experiment on COVID-19 con-firms that the proposed DTA model can be used as an effective pre-screening tool in drug discovery. 展开更多
关键词 compound microstructure drug-target interaction binding affinity deep learning COVID-19
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Local and global approaches of affinity propagation clustering for large scale data 被引量:15
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作者 Ding-yin XIA Fei WU +1 位作者 Xu-qing ZHAN Yue-ting ZHUANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2008年第10期1373-1381,共9页
Recently a new clustering algorithm called 'affinity propagation' (AP) has been proposed, which efficiently clustered sparsely related data by passing messages between data points. However, we want to cluster ... Recently a new clustering algorithm called 'affinity propagation' (AP) has been proposed, which efficiently clustered sparsely related data by passing messages between data points. However, we want to cluster large scale data where the similarities are not sparse in many cases. This paper presents two variants of AP for grouping large scale data with a dense similarity matrix. The local approach is partition affinity propagation (PAP) and the global method is landmark affinity propagation (LAP). PAP passes messages in the subsets of data first and then merges them as the number of initial step of iterations; it can effectively reduce the number of iterations of clustering. LAP passes messages between the landmark data points first and then clusters non-landmark data points; it is a large global approximation method to speed up clustering. Experiments are conducted on many datasets, such as random data points, manifold subspaces, images of faces and Chinese calligraphy, and the results demonstrate that the two ap-proaches are feasible and practicable. 展开更多
关键词 CLUSTERING affinity propagation Large scale data Partition affinity propagation Landmark affinity propagation
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Characteristics and Affinity of Tropical Flora in Southern China 被引量:6
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作者 朱华 M.C.Roos 《Forestry Studies in China》 CAS 2002年第1期18-24,共7页
The tropical flora in southern China is represented mainly by three regional flora, i.e. southern Yunnan (southwestern China), southwestern Guangxi (southwestern China) and Hainan Island (southern China). The floristi... The tropical flora in southern China is represented mainly by three regional flora, i.e. southern Yunnan (southwestern China), southwestern Guangxi (southwestern China) and Hainan Island (southern China). The floristic composition of each is concisely enumerated. Their geographical elements at generic level are analyzed. Furthermore, a comparison of floristic similarities between southern Yunnan and Hainan Island and Malay Peninsula and Brunei of western Malesia is made, based on existing regional flora treatments. The following is concluded: (1) The flora of southern China consists mainly of tropical floristic elements which contribute about 60% at the family level and more than 80 % at the generic level of its total flora. The dominant distribution type of the flora of southern China at the generic level is the tropical Asian distribution pattern. This reveals that the flora of southern China is of tropical nature with a strong tropical Asian affinity; (2) Most of the dominant families from the flora of southern China are also dominant in the Malesian flora. The floristic similarities between the regional flora of southern China and the regional flora of western Malesia are over 70% at the family level and more than 50% at the generic level. This suggests that the tropical flora of southern China belongs to the Malesian floristic region; (3) Situated at the northern margin of tropical Asia, on the other hand it is also obvious that the flora of southern China comprises less strictly tropical elements compared to the Malesian flora, and is consequently only a marginal type of the latter; (4) The close affinity of the flora of southern China to the Malesian flora can be explained by the geological history of southeast Asia. 展开更多
关键词 southern China FLORA floristic composition affinity
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Affinity Chromatography Purification of Recombinant Human Interleukin-6 from Its Fusion Protein with GST
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作者 吴蕾 甘一如 +1 位作者 林峰 黄鹤 《Transactions of Tianjin University》 EI CAS 2002年第2期106-109,共4页
Recombinant E.coli JM109, containing pHZ1818 plasmid which included the fused gene encoding human interleukin 6(IL 6), expressed a fusion protein with glutathion S transferase(GST). The fusion protein existed both... Recombinant E.coli JM109, containing pHZ1818 plasmid which included the fused gene encoding human interleukin 6(IL 6), expressed a fusion protein with glutathion S transferase(GST). The fusion protein existed both in the supernatant and inside the bacterial cell,but the insoluble protein had no biological activity and could not be refolded. The rotative speed of the shaker and the temperature of induction were optimized to maximize the expression of the soluble fusion protein. From the supernatant of the cell sonicates Glutathion Sephrose 4B affinity column chromatography was employed to isolate the fusion protein which could be purified to >80 0 0 in a single step. The yield of soluble GST IL 6 was about 10 mg per liter culture. The GST was site specifically cloven by 6 hours of treatment with thrombin and from the thrombin digest mixture IL 6 was purified by Q high performance ion exchange chromatography. From 1 liter of E.coli culture 2 mg refined IL 6 was obtained. The purified IL 6 had a purity of more than 95 0 0 and a biological activity of 1.02×10 8 IU/mg. 展开更多
关键词 affinity purification human interleukin 6 fusion protein GST
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Separation of Proteins by Electrophoretic Affinity Chromatography
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作者 酆韶骅 刘铮 +1 位作者 丁富新 袁乃驹 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1999年第4期315-320,共6页
A new kind of electrophoretic affinity chromatography (EAC) for bioseparation was proposed. Separation by EAC was conducted in a multicompartment electrolyzer in which the affinity gel media were packed in one of the ... A new kind of electrophoretic affinity chromatography (EAC) for bioseparation was proposed. Separation by EAC was conducted in a multicompartment electrolyzer in which the affinity gel media were packed in one of the central compartments. The presence of an electric field accelerated the migration of proteins inside the gel matrix during adsorption and desorption processes. This led to the increase of the overall speed of separation. The present study was focused on the effect of the strength of the electric field on adsorption and desorption processes. 展开更多
关键词 affinity chromatography ELECTROPHORESIS electrophoretic affinity chromatography human serum albumin Cibacron Blue F3G-A
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Improved Recovery of Erythropoietin and Darbepoetin from Equine Plasma by the Application of a Wheat Germ Agglutinin Mediated Pre-Extraction Prior to Immunoaffinity Chromatography
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作者 Shawn M. R. Stanley Danny Chua 《Advances in Bioscience and Biotechnology》 2014年第7期651-660,共10页
We describe a two-step method that uses wheat germ agglutinin immobilized on Sepharose gel followed by immunoaffinity chromatography (IAC) to extract recombinant human erythropoietin and Darbepoetin from equine plasma... We describe a two-step method that uses wheat germ agglutinin immobilized on Sepharose gel followed by immunoaffinity chromatography (IAC) to extract recombinant human erythropoietin and Darbepoetin from equine plasma. Lectin affinity chromatography was shown to be an effective approach for isolating these epoetins from plasma and in combination with IAC;this method gave superior recovery when compared to the use of the latter technique alone. Moreover, due to the ease with which it can be scaled up, it is particularly well suited for pre-concentrating larger volumes of samples prior to IAC and this provides a facile way of improving the overall sensitivity with which these foreign proteins can be detected in equine plasma. 展开更多
关键词 ERYTHROPOIETIN DARBEPOETIN Alfa IMMUNOaffinity EXTRACTION Lectin affinity EXTRACTION Wheat GERM AGGLUTININ Horseracing
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Affinity and fluorescent detection of surfactants/ssDNA and single-walled carbon nanotube 被引量:1
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作者 周姣 李娟萍 +2 位作者 聂钰洪 李继山 杨金凤 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第2期456-461,共6页
A new biosensor platform was explored for detection of surfactant based on fluorescence changes from single strand DNA (ssDNA) and single-walled carbon nanotubes (SWNTs). Thermodynamics assay was performed to valu... A new biosensor platform was explored for detection of surfactant based on fluorescence changes from single strand DNA (ssDNA) and single-walled carbon nanotubes (SWNTs). Thermodynamics assay was performed to value the stability of probe. The affinities of SWNT to five common surfactants (SDS, DBS, Triton X-100, Tween-20 and Tween-80) were investigated by real-time fluorescence method. The effects of Mg^2+ and pH on the fluorescence intensity of self-assembled quenched sensor were performed. The fluorescent emission spectra were used to measure the responses of self-assembled quenched fluorescent of ssDNA/SWNTs to different concentration surfactant(Triton X-100). The FAM-DNA wrapped SWNTs probe was stable in a wide temperature range (5 ℃ to 80℃). The binding strength of surfactants and single-stranded DNA (ssDNA) on SWNTs surfaces was shown as follows: Triton X-100〉DBS〉Tween-20〉Tween-80〉ssDNA〉SDS, and the optimized reaction conditions included pH 7.4 and 10 mmol/L Mg2+. The fluorescence of FAM-ssDNA wrapped SWNTs was proportionally recovered as a result of adding different concentrations of Triton X- 100, which realizes the quantitative detection of Triton X- 100. 展开更多
关键词 single-stranded DNA single-walled carbon nanotubes SURFACTANT fluorescent sensor affinity
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Method and Progress of the Research on Virus Affinity Peptide 被引量:1
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作者 张娜娜 卢清侠 +3 位作者 滕蔓 杨艳艳 张以芳 张改平 《Agricultural Science & Technology》 CAS 2016年第12期2713-2716,2725,共5页
With the continuous progress on affinity peptide research, it has become more and more popular in pharmacology and medicine. lt is promising to study these viruses affinity peptide to treat infectious diseases. And th... With the continuous progress on affinity peptide research, it has become more and more popular in pharmacology and medicine. lt is promising to study these viruses affinity peptide to treat infectious diseases. And the analysis on the virus affinity peptide with high selectivity and high sensitivity could provide valuable means for disease detection, treatment as wel as the study on the molecular mechanism of virus affinity peptide. Therefore, we reviewed the bioinformatics pre-diction technologies of computer simulation, molecular docking and homology model-ing, as wel as the research method on analyzing and screening virus affinity pep-tide, such as Phage display technology. 展开更多
关键词 Virus affinity peptide BIOINFORMATICS Homology modeling Phage display technology
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基于Affinity Propagation算法的半监督微博水军识别 被引量:3
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作者 林义钧 吴渝 李红波 《信息网络安全》 CSCD 北大核心 2022年第3期85-96,共12页
对微博网络空间中水军账户的识别研究,有助于清朗网络空间和维护社会安定。首先,文章针对微博水军不断进化、传统特征集无法覆盖现有水军特征,结合水军定义与原始特征,构造了新特征。然后,针对水军账户标注困难,无标注数据又没能充分利... 对微博网络空间中水军账户的识别研究,有助于清朗网络空间和维护社会安定。首先,文章针对微博水军不断进化、传统特征集无法覆盖现有水军特征,结合水军定义与原始特征,构造了新特征。然后,针对水军账户标注困难,无标注数据又没能充分利用的问题,提出了一种基于Affinity Propagation算法的半监督微博水军识别方法(APDHW)。该方法通过在Affinity Propagation算法中引入欧氏距离Radius阈值,再结合支持向量机分类算法,实现对微博水军识别。通过多组实验对比及实证研究,结果表明文章所提的微博水军识别方法在牺牲少量算法时间的情况下得到较好的识别效果,提升了水军识别的准确率和召回率。 展开更多
关键词 微博水军 affinity Propagation 半监督学习 水军识别
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基于Affinity Propagation聚类方法的图像检索技术在数字图书馆中的应用 被引量:4
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作者 万洁 《计算机与现代化》 2008年第8期116-119,共4页
随着数字图书馆包含的内容逐渐丰富,数字图像也越来越多。为了有效地检索这些图像,迫切需要一种效率更高的检索方法。目前的基于内容的图像检索算法在检索时间和效率上都还不能满足这一需求。本文采用最新提出的Af-finity Propagation... 随着数字图书馆包含的内容逐渐丰富,数字图像也越来越多。为了有效地检索这些图像,迫切需要一种效率更高的检索方法。目前的基于内容的图像检索算法在检索时间和效率上都还不能满足这一需求。本文采用最新提出的Af-finity Propagation聚类方法和颜色-形状直方图特征,提出一种新的检索方法应用到数字图书馆进行图像检索。经过试验证明在查准率、查全率和检索时间上均有较大的提高。 展开更多
关键词 图像检索 数字图书馆 affinity Propagation CLUSTER 颜色.形状直方图
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Multiple Model Soft Sensor Based on Affinity Propagation, Gaussian Process and Bayesian Committee Machine 被引量:32
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作者 李修亮 苏宏业 褚健 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第1期95-99,共5页
Presented is a multiple model soft sensing method based on Affinity Propagation (AP), Gaussian process (GP) and Bayesian committee machine (BCM). AP clustering arithmetic is used to cluster training samples acco... Presented is a multiple model soft sensing method based on Affinity Propagation (AP), Gaussian process (GP) and Bayesian committee machine (BCM). AP clustering arithmetic is used to cluster training samples according to their operating points. Then, the sub-models are estimated by Gaussian Process Regression (GPR). Finally, in order to get a global probabilistic prediction, Bayesian committee mactnne is used to combine the outputs of the sub-estimators. The proposed method has been applied to predict the light naphtha end point in hydrocracker fractionators. Practical applications indicate that it is useful for the online prediction of quality monitoring in chemical processes. 展开更多
关键词 multiple model soft sensor affinity propagation Gaussian process Bayesian committee machine
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Implications from protein uptake kinetics onto dextran-grafted Sepharose FF coupled with ion exchange and affinity ligands 被引量:10
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作者 Aiying Xue Linling Yu Yan Sun 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第7期906-910,共5页
Our previous studies have reported the presence of "chain delivery" effects of protein adsorption onto ion exchangers with polymer-grafted ion-exchange groups, such as dextran-grafted and poly(ethylenimine)-... Our previous studies have reported the presence of "chain delivery" effects of protein adsorption onto ion exchangers with polymer-grafted ion-exchange groups, such as dextran-grafted and poly(ethylenimine)-modified Sepharose gels. However, it is unclear if the "chain delivery" occurs on affinity adsorption with specific interactions. This work is designed to address this issue. A dextran-grafted Sepharose gel was prepared, and then the matrix was modified using diethylaminoethyl, a typical ion-exchange group, or octapeptide(FYCHWQDE), an affinity ligand for human immunoglobulin G(h Ig G) to prepare ion-exchange or affinity adsorbents, respectively.Results of h Ig G adsorption showed that the uptake rate represented by the effective diffusivity of h Ig G onto the dextran-grafted ion exchangers was obviously enhanced by the dextran grafting, indicating the presence of"chain delivery" of the bound proteins on the charged groups on the dextran chains. By contrast, the effective diffusivity of h Ig G changed little as ligand density increased on the dextran-grafted FYCHWQDE adsorbents.Their adsorption capacities decreased and effective diffusivities were not accelerated by the dextran grafting.Thus, this work clarified that grafted dextran could not accelerate h Ig G uptake rate on the affinity resins, or in other words, chain delivery did not occur on the specific interaction-based affinity adsorption. 展开更多
关键词 Dextran-grafted adsorbent Ion exchange chromatography affinity chromatography lmmunoglobulin G KINETICS
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Male spike strobiles with Gnetum affinity from the Early Cretaceous in western Liaoning,Northeast China 被引量:5
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作者 Shuang-Xing GUO jin-Geng SHA +1 位作者 Li-Zeng BIAN Yin-Long QIU 《Journal of Systematics and Evolution》 SCIE CSCD 北大核心 2009年第2期93-102,共10页
A fossil with Gnetum affinity was found in the Jianshangou Member (Barremian Age) of the Yixian Formation (Lower Cretaceous Epoch) of the Jehol Group in western Liaoning, northeastern China. The single fossil spec... A fossil with Gnetum affinity was found in the Jianshangou Member (Barremian Age) of the Yixian Formation (Lower Cretaceous Epoch) of the Jehol Group in western Liaoning, northeastern China. The single fossil specimen is represented by both elongate-cylindrical male spike strobiles which borne within a nodal bract of cauliflorous branch. The spike strobiles have apparent nodes, invisible internodes, and numerous verticillate involucral collars. The microsporangiate units within involucral collars are not seen. The male spike strobiles with verticillate involucral collars occur exclusively in Gnetum; hence, the fossil strobiles are attributed to a new taxon, Khitania columnispicata gen. & sp. nov., being closely related to Gnetum. The general isotopic dating suggests an age of Barremian, ca. 125-122 million years (Myr) ago for the Jianshangou Member. The palaeoecological and palaeoclimatic inference based on the compositions of flora and fauna, and lithological characters of the fossil locality suggests that the fossil plants grew in a subtropical mesophytic forest and under a warmer climate. The remains of male spike strobiles are the first record of gnetalean macrofossil. It documents the evolution of the distinct gnetoid morphology and indicates a wider range of distribution of Gnetaceae in the Early Cretaceous than present day. 展开更多
关键词 BIOGEOGRAPHY Early Cretaceous Gnetum affinity male spike strobiles northeastern China.
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Removing Endotoxin from Protein Solution by Chitosan Modified Affinity Membrane 被引量:5
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作者 SUN Haixiang(孙海翔) +5 位作者 ZHANG Lin(张林) CHAI Hong(柴红) CHEN Huanlin(陈欢林) 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第4期457-463,共7页
Affinity membrane was prepared with chitosan immobilized on the hydrophile- modified poly(vinylidene fluoride) (PVDF) membrane. Fourier transform infrared spectroscopy (FTIR.) analysis indicated that the contents of ... Affinity membrane was prepared with chitosan immobilized on the hydrophile- modified poly(vinylidene fluoride) (PVDF) membrane. Fourier transform infrared spectroscopy (FTIR.) analysis indicated that the contents of —NH2 and —OH groups increased and fluoride decreased on the membrane surface after modification. Using this kind of affinity membrane, the effects of operation parameters such as pH, ionic strength and flow rate, on the amount of endotoxin removed were investigated. The results showed that the equilibrium adsorption capacity and the dissociation constant of the affinity membrane to endotoxin were 21.4 EU·mg-1 membrane and 0.50EU·ml-1, respectively, at pH 7.0 and ionic strength 0.2 mol·L-1. Adsorption appeared to follow a typical Langmuir adsorption isotherm. At pH 5.0, ionic strength of 0.2 mol·L-1, the removal rate of endotoxin from BSA solution with the chitosan affinity membrane was up to 88.6% (11.50 EU·mg-1 membrane), and the recovery of BSA was 93.4% (0.187mg·mg-1 membrane), while at pH 11.0, ionic strength of 0.2mol·L-1, the removal rate of endotoxin from lysozyme solution was 72.4% (9.92EU·mg-1 membrane), and the recovery of lysozyme was 92.3% (0.104 mg·mg-1 membrane). 展开更多
关键词 CHITOSAN poly(vinylidene fluoride) endotoxin removal affinity adsorption
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