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非洲航运枢纽及网络特征分析
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作者 顾晓洁 封学军 《中国港湾建设》 2024年第2期21-25,共5页
枢纽布局和网络特征是区域航运业发展的重要基础。基于复杂网络理论,运用TOPSIS法和多重流分析法分析非洲排名前20的枢纽港口,发现非洲航运网络的整体均衡性较弱,区域内航运网络发展不平衡、不充分,呈现显著的西密东疏、北强南弱的现象... 枢纽布局和网络特征是区域航运业发展的重要基础。基于复杂网络理论,运用TOPSIS法和多重流分析法分析非洲排名前20的枢纽港口,发现非洲航运网络的整体均衡性较弱,区域内航运网络发展不平衡、不充分,呈现显著的西密东疏、北强南弱的现象。通过与全球主要区域港口承担的显著流数量对比,发现非洲主要港口的承担显著流数量较大部分区域低,表明非洲航运业在全球范围内影响力较弱。基于此,提出了未来域内航运网络重点发展区域,为海上互联互通的实现提供参考。 展开更多
关键词 非洲 航运枢纽 TOPSIS法 多重流分析法 网络特征
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MEMS近红外光谱仪微镜驱动控制系统研发 被引量:1
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作者 顾小杰 王杰 《测控技术》 CSCD 2018年第11期129-133,共5页
针对微机电系统(MEMS)近红外光谱仪中MEMS微镜驱动系统的耦合与复杂扰动问题,提出了一种基于扰动观测器(DOB)与模型预测控制(MPC)的复合控制结构。通过分析MEMS微镜的驱动工作原理,建立MEMS微镜偏转角与驱动电压的传递函数模型,设计了MP... 针对微机电系统(MEMS)近红外光谱仪中MEMS微镜驱动系统的耦合与复杂扰动问题,提出了一种基于扰动观测器(DOB)与模型预测控制(MPC)的复合控制结构。通过分析MEMS微镜的驱动工作原理,建立MEMS微镜偏转角与驱动电压的传递函数模型,设计了MPC以消除系统耦合,通过分析系统扰动模型,设计了DOB实现对系统内部与外部扰动的集中监测。仿真研究与实验测试结果表明:基于DOB-MPC复合结构的MEMS微镜驱动控制系统,既可以有效抑制系统的外部扰动,又可以抑制由模型失配和变量耦合导致的内部扰动。 展开更多
关键词 扰动观测器 模型预测控制 MEMS 微镜 近红外
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弹性体增韧聚丙烯材料橡胶形貌的研究 被引量:3
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作者 赵鹏伟 谷晓杰 孙刚 《合成材料老化与应用》 2022年第3期14-16,共3页
选用与聚丙烯相容性优异的弹性体A、相容性一般的弹性体B作为增韧剂,研究弹性体的含量对材料橡胶形貌的影响。研究发现,随着弹性体含量的增加,两种弹性体改性的聚丙烯材料橡胶形貌都经历了从球状到条状的形貌突变,其中相容性优异的弹性... 选用与聚丙烯相容性优异的弹性体A、相容性一般的弹性体B作为增韧剂,研究弹性体的含量对材料橡胶形貌的影响。研究发现,随着弹性体含量的增加,两种弹性体改性的聚丙烯材料橡胶形貌都经历了从球状到条状的形貌突变,其中相容性优异的弹性体A在含量20%~25%(wt.)出现了形貌突变,相容性一般的弹性体B在含量15%~20%出现了形貌突变。进一步研究发现,在25%弹性体B增韧聚丙烯材料中将其中2.0%的弹性体B替换成2.0%的弹性体A,从而改善弹性体B与聚丙烯材料的相容性之后,其橡胶形貌从条状分布变为球状分布。最终研究结果表明,弹性体与聚丙烯材料的相容性对最终的弹性体形貌有着重要影响,弹性体与聚丙烯材料的相容性越好,其橡胶形貌趋向于球状分布,弹性体与聚丙烯材料的相容性越差,其橡胶形貌趋向于条状分布。 展开更多
关键词 聚丙烯 弹性体 扫描透射电镜 橡胶形貌
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PMMA含量对ASA/PMMA合金材料的影响 被引量:2
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作者 谷晓杰 冉敏 +2 位作者 朱春龙 陆佳琦 孟涛 《塑料工业》 CAS CSCD 北大核心 2020年第11期51-54,共4页
以丙烯腈-苯乙烯-丙烯酸酯共聚物(ASA)/聚甲基丙烯酸甲酯(PMMA)合金为研究对象,考察了不同PMMA含量对共混合金材料外观、力学性能、耐候性能和耐刮擦性能的影响。研究结果表明,PMMA的加入可以有效改善材料的外观、耐候性能,但随着PMMA... 以丙烯腈-苯乙烯-丙烯酸酯共聚物(ASA)/聚甲基丙烯酸甲酯(PMMA)合金为研究对象,考察了不同PMMA含量对共混合金材料外观、力学性能、耐候性能和耐刮擦性能的影响。研究结果表明,PMMA的加入可以有效改善材料的外观、耐候性能,但随着PMMA的添加量逐渐增多,尤其是PMMA添加量在20%以上时,材料的冲击强度出现明显下降趋势;PMMA添加量过低时材料的耐刮擦性能改善不明显,当添加量超过20%有部分改善。 展开更多
关键词 丙烯腈-苯乙烯-丙烯酸酯共聚物 聚甲基丙烯酸甲酯 耐候 耐刮擦
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Recent advances in phytochemistry and pharmacology of C_(21) steroid constituents from Cynanchum plants 被引量:11
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作者 gu xiao-jie HAO Da-Cheng 《Chinese Journal of Natural Medicines》 SCIE CAS CSCD 2016年第5期321-334,共14页
Cynanchum is one of the most important genera in Asclepiadaceae family, which has long been known for its therapeutic effects. In this genus, 16 species are of high medicinal value. The extracts of the root and/or rhi... Cynanchum is one of the most important genera in Asclepiadaceae family, which has long been known for its therapeutic effects. In this genus, 16 species are of high medicinal value. The extracts of the root and/or rhizome parts have been applied in traditional Chinese medicines(TCM) for the prevention and treatment of various illnesses for centuries. C21 steroids, as the typical constituents of Cynanchum species, possess a variety of structures and pharmacological activities. This review summarizes the comprehensive information on phytochemistry and pharmacology of C21 steroid constituents from Cynanchum plants, based on reports published between 2007 and 2015. Our aim is to provide a rationale for their therapeutic application, and to discuss the future trends in research and development of these compounds. A total of 172 newly identified compounds are reviewed according to their structural classifications. Their in vitro and in vivo pharmacological studies are also reviewed and discussed, focusing on antitumor, antidepressant, antifungal, antitaging, Na+/K+-ATPase inhibitory, appetite suppressing and antiviral activities. Future research efforts should concentrate on in vitro and in vivo biological studies and structure activity relationship of various C21 steroid constituents. 展开更多
关键词 ASCLEPIADACEAE CYNANCHUM C21 steroid constituents Phytochemical studies Pharmacological actions
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Recent Advance in Chemical and Biological Studies on Cimicifugeae Pharmaceutical Resources 被引量:9
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作者 HAO Da-cheng gu xiao-jie +3 位作者 XIAO Pei-gen LIANG Zhan-guo XU Li-jia PENG Yong 《Chinese Herbal Medicines》 CAS 2013年第2期81-95,共15页
Cimicifugeae is one of the rich sources for various active components and the health promoting and therapeutic values of the components have been corroborated by long-term use in folk medicine and traditional Chinese ... Cimicifugeae is one of the rich sources for various active components and the health promoting and therapeutic values of the components have been corroborated by long-term use in folk medicine and traditional Chinese medicine.Increasing interest in Cimicifugeae pharmaceutical resources has led to the further discoveries of triterpenoid saponins, phenolic compounds, chromones, and many other compounds in various species of Cimicifugeae, and to the investigations on their chemotaxonomy, molecular phylogeny, and bioactivities. Based on our pharmacophylogenetic studies, the progress in phytochemistry, chemotaxonomy, molecular biology, and phylogeny of Cimicifugeae had been summarized since 2007, especially Cimicifuga L. ex Wernisch. and Actaea L., and their relevance to therapeutic efficacy. An exhaustive literature survey is used to characterize the global scientific effort in the phytochemical and biological studies of Cimicifugeae. More triterpenoid saponins have been found in various species, among which the cimigenol type(type A) is predominant. The versatile bioactivities of saponins and extracts,as well as those of phenolics and other ingredients, were summarized and discussed. The morphology-based five-genus classification of Cimicifugeae is not supported by molecular phylogeny. Molecular phylogeny based on nuclear and chloroplast DNA sequences tends to merge Cimicifuga Wernisch., Souliea Franch., and Actaea L. into a single genus. It is indispensable to integrate the emerging technologies into Cimicifugeae research for both the sustainable utilization of Cimicifugeae pharmaceutical resources and finding novel compounds with potential clinical utility and less adverse effects. Systems biology and omics technologies would play an increasingly important role in booming pharmaceutical research involving bioactive compounds of Cimicifugeae. 展开更多
关键词 biological activity CHEMOTAXONOMY Cimicifugeae pharmaceutical resource PHYLOGENY PHYTOCHEMISTRY
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Ethnopharmacology,chemodiversity,and bioactivity of Cephalotaxus medicinal plants 被引量:4
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作者 HAO Da-Cheng HOU Xu-Dong +2 位作者 gu xiao-jie XIAO Pei-Gen GE guang-Bo 《Chinese Journal of Natural Medicines》 SCIE CAS CSCD 2021年第5期321-338,共18页
Cephalotaxus is the only genus of Cephalotaxaceae family,and its natural resources are declining due to habitat fragmentation,excessive exploitation and destruction.In many areas of China,folk herbal doctors tradition... Cephalotaxus is the only genus of Cephalotaxaceae family,and its natural resources are declining due to habitat fragmentation,excessive exploitation and destruction.In many areas of China,folk herbal doctors traditionally use Cephalotaxus plants to treat innominate swollen poison,many of which are cancer.Not only among Han people,but also among minority ethnic groups,Cephalotaxus is used to treat various diseases,e.g.,cough,internal bleeding and cancer in Miao medicine,bruises,rheumatism and pain in Yao medicine,and ascariasis,hookworm disease,scrofula in She medicine,etc.Medicinal values of some Cephalotaxus species and compounds are acknowledged officially.However,there is a lack of comprehensive review summarizing the ethnomedicinal knowledge o f Cephalotaxus,relevant medicinal phytometabolites and their bioactivities.The research progresses in ethnopharmacology,chemodiversity,and bioactivities of Cephalotaxus medicinal plants are reviewed and commented here.Knowledge gaps are pinpointed and future research directions are suggested.Classic medicinal books,folk medicine books,herbal manuals and ethnomedicinal publications were reviewed for the genus Cephalotaxus(Sanjianshan in Chinese).The relevant data about ethnobotany,phytochemistry,and pharmacology were collected as comprehensively as possible from online databases including Scopus,NCBI PubMed,Bing Scholar,and China National Knowledge Infrastructure(CNKI).44 Cephalotaxus"',and the respective species name were used as keywords in database search.The obtained articles of the past six decades were collated and analyzed.Four Cephalotaxus species are listed in the official medicinal book in China.They are used as ethnomedicines by many ethnic groups such as Miao,Yao,Dong,She and Han.Inspirations are obtained from traditional applications,and Cephalotaxus phytometabolites are developed into anticancer reagents.Cephalotaxine-type alkaloids,homoerythrina-type alkaloids and homoharringtonine(HHT)are abundant in Cephalotaxus,e.g.,C.lanceolata,C.fortunei var.alpina,C.griffithii,and C.hainanensis,etc.New methods of alkaloid analysis and purification are continuously developed and applied.Diterpenoids,sesquiterpenoids,flavonoids,lignans,phenolics,and other components are also identified and isolated in various Cephalotaxus species.Alkaloids such as HHT,terpenoids and other compounds have anticancer activities against multiple types of human cancer.Cephalotaxus extracts and compounds showed anti-inflammatory and antioxidant activities,immunomodulatory activity,antimicrobial activity and nematotoxicity,antihyperglycemic effect,and bone effect,etc.Drug metabolism and pharmacokinetic studies o f Cephalotaxus are increasing.We should continue to collect and sort out folk medicinal knowledge of Cephalotaxus and associated organisms,so as to obtain new enlightenment to translate traditional tips into great therapeutic drugs.Transcriptomics,genomics,metabolomics and proteomics studies can contribute massive information for bioactivity and phytochemistry of Cephalotaxus medicinal plants.We should continue to strengthen the application of state-of-the-art technologies in more Cephalotaxus species and for more useful compounds and pharmacological activities. 展开更多
关键词 Cephalotaxus ETHNOMEDICINE Chemodiversity ALKALOIDS Bioactivity PHARMACOLOGY
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