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Developments in the study of Chinese herbal medicine's assessment index and action mechanism for diabetes mellitus
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作者 Xin-Yue Liu Han-Wen Zheng +3 位作者 Feng-Zhong Wang Tul-Wahab Atia Bei Fan Qiong Wang 《Animal Models and Experimental Medicine》 CAS CSCD 2024年第4期433-443,共11页
In traditional Chinese medicine(TCM),based on various pathogenic symptoms and the‘golden chamber’medical text,Huangdi Neijing,diabetes mellitus falls under the category‘collateral disease’.TCM,with its wealth of e... In traditional Chinese medicine(TCM),based on various pathogenic symptoms and the‘golden chamber’medical text,Huangdi Neijing,diabetes mellitus falls under the category‘collateral disease’.TCM,with its wealth of experience,has been treating diabetes for over two millennia.Different antidiabetic Chinese herbal medicines re-duce blood sugar,with their effective ingredients exerting unique advantages.As well as a glucose lowering effect,TCM also regulates bodily functions to prevent diabetes associated complications,with reduced side effects compared to western synthetic drugs.Chinese herbal medicine is usually composed of polysaccharides,saponins,al-kaloids,flavonoids,and terpenoids.These active ingredients reduce blood sugar via various mechanism of actions that include boosting endogenous insulin secretion,enhancing insulin sensitivity and adjusting key enzyme activity and scavenging free radicals.These actions regulate glycolipid metabolism in the body,eventually achiev-ing the goal of normalizing blood glucose.Using different animal models,a number of molecular markers are available for the detection of diabetes induction and the molecular pathology of the disease is becoming clearer.Nonetheless,there is a dearth of scientific data about the pharmacology,dose-effect relationship,and structure-activity relationship of TCM and its constituents.Further research into the efficacy,toxicity and mode of action of TCM,using different metabolic and molecular markers,is key to developing novel TCM antidiabetic formulations. 展开更多
关键词 animal model Chinese herbal medicine diabetes mellitus evaluation index mechanism of action
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An aqueous BiI_(3)-Zn battery with dual mechanisms of Zn^(2+)(de)intercalation and I^(-)/I_(2)redox
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作者 Qi Deng Fangzhong Liu +3 位作者 Xiongwei Wu Changzhu Li Weibin Zhou Bei Long 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第2期670-678,I0014,共10页
The development of aqueous battery with dual mechanisms is now arousing more and more interest.The dual mechanisms of Zn^(2+)(de)intercalation and I^(-)/I_(2)redox bring unexpected effects.Herein,differing from previo... The development of aqueous battery with dual mechanisms is now arousing more and more interest.The dual mechanisms of Zn^(2+)(de)intercalation and I^(-)/I_(2)redox bring unexpected effects.Herein,differing from previous studies using Zn I_(2)additive,this work designs an aqueous Bi I_(3)-Zn battery with selfsupplied I^(-).Ex situ tests reveal the conversion of Bi I_(3)into Bi(discharge)and Bi OI(charge)at the 1st cycle and the dissolved I^(-)in electrolyte.The active I^(-)species enhances the specific capacity and discharge medium voltage of electrode as well as improves the generation of Zn dendrite and by-product.Furthermore,the porous hard carbon is introduced to enhance the electronic/ionic conductivity and adsorb iodine species,proven by experimental and theoretical studies.Accordingly,the well-designed Bi I_(3)-Zn battery delivers a high reversible capacity of 182 m A h g^(-1)at 0.2 A g^(-1),an excellent rate capability with 88 m A h g^(-1)at 10 A g^(-1),and an impressive cyclability with 63%capacity retention over 20 K cycles at 10 A g^(-1).An excellent electrochemical performance is obtained even at a high mass loading of 6 mg cm^(-2).Moreover,a flexible quasi-solid-state Bi I_(3)-Zn battery exhibits satisfactory battery performances.This work provides a new idea for designing high-performance aqueous battery with dual mechanisms. 展开更多
关键词 Aqueous BiI_(3)-Zn battery Dual mechanisms I^(-)-induced uniform zinc deposition Ultralong cyclic life Flexible quasi-solid-state battery
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Inhibitory Effect of Flavonoid Glycosides from Chlorophytum comosum on Nasopharyngeal Carcinoma 5-8F Cells and Its Mechanism
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作者 Chenliang CHU Xinchen WANG +2 位作者 Kuan LU Liang QIN Lu JIN 《Medicinal Plant》 2024年第1期66-70,共5页
[Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavo... [Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavonoid glycosides were isolated and purified from the ethanol alcoholic extract of the roots of Liliaceae plant Chlorophytum comosum by silica gel column chromatography,macroporous resin column chromatography,Sephadex LH-20,and reverse column chromatography(ODS).The inhibitory activity of flavonoid glycosides on human nasopharyngeal carcinoma cells was analyzed by CCK-8 method,and the potential mechanism was preliminarily analyzed by molecular docking.[Results]Two flavonoid glycosides were identified as isovitexin 2″-0-rhamnoside and 7-2″-di-O-β-glucopyranosylisovitexin.Two flavonoid glycosides showed promising inhibitory effect on human nasopharyngeal carcinoma cell line 5-8F,with IC_(50) values of 24.8 and 27.5μmol/L,respectively.Molecular docking results showed that the potential targets of two flavonoid glycosides include CyclinD1,Bcl-2β-Catenin,ILK,TGF-β,in addition,two glycosides showed higher predicted binding affinity towards CyclinD1,which verifies the cytotoxicity of the two compounds on human nasopharyngeal carcinoma cell line 5-8F in vitro.[Conclusions]Two flavonoid glycosides are the active molecules in Chlorophytum comosum that can inhibit the proliferation of human nasopharyngeal carcinoma cells,and have the potential to be used in the research and development of anti nasopharyngeal carcinoma drugs. 展开更多
关键词 Chlorophytum comosum Laxum R.Br. Flavonoid glycosides 5-8F cells Antitumor mechanism
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Prediction for Dynamic Characteristics of Ring-Plate Planetary Indexing Cam Mechanism 被引量:2
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作者 宋轶民 田广才 +2 位作者 张俊 刘明涛 刘建平 《Transactions of Tianjin University》 EI CAS 2009年第4期249-254,共6页
This paper is aimed to propose an approach to predict the dynamic characteristics of ring-plate planetary indexing cam mechanism, which is a novel type of indexing mechanism that employs internal planetary transmissio... This paper is aimed to propose an approach to predict the dynamic characteristics of ring-plate planetary indexing cam mechanism, which is a novel type of indexing mechanism that employs internal planetary transmission structure. Firstly, the geometry and structure of the mechanism are discussed and the kinematic practicability is simulated with virtual prototype design. Then a 3D finite element model of the ring-plate planetary indexing cam mechanism is developed with the commercial software of MATLAB and ANSYS. Through the finite element analysis, the natural frequencies and the corresponding mode shapes are predicted in one motion cycle. On the basis of the virtual prototype design and finite element analysis, an experimental prototype is made and tested to validate the prediction of the dynamic characteristics. The agreement between experimental results and the finite element analysis testifies that the finite element model developed is applicable to the prediction of the dynamic characteristics of this type of mechanism. 展开更多
关键词 ring-plate planetary indexing cam mechanism virtual prototype design finite element mode analysis
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Kinematics and dynamics analysis of a 3-7R parallel decoupling mechanism 被引量:2
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作者 郑建勇 史金飞 +1 位作者 张志胜 李为民 《Journal of Southeast University(English Edition)》 EI CAS 2008年第2期183-187,共5页
One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R (revolute-pair) parallel decoupling mechanism, and the mechanism's characteristics are summarized. The mechanism has three ... One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R (revolute-pair) parallel decoupling mechanism, and the mechanism's characteristics are summarized. The mechanism has three orthogonal distributional branch-chains, and all movable pairs are rotational joints. The movable platform of the mechanism has x, y, z translational decoupling directions. Furthermore, in order to verify the mechanism's decoupling characteristics, the mechanism's kinematics analysis is solved, and the mechanism's direct/inverse kinematics model, input/output velocities and accelerations are deduced, which confirm its decoupling movement characteristics. Finally, one kind of mechanism link decomposed-integrated approach is adopted, and the mechanism's dynamics model is completed with the Lagrange method, which also proves its decoupling force characteristics. All of these works provide significant theory for the further study of the mechanism's control strategy, design, path planning etc. 展开更多
关键词 3-7R parallel decoupling mechanism KINEMATICS DYNAMICS DECOUPLING
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GC-MS结合电子鼻技术对不同茶区茉莉花茶香气的差异比较 被引量:1
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作者 李璐 尹礼国 +4 位作者 陆安霞 王秋卫 陈丽 赵先明 黄彤 《现代食品科技》 CAS 北大核心 2024年第2期302-311,共10页
为探究不同产区茉莉花茶香气差异,采用气相色谱-质谱(GasChromatography-Mass Spectrometry,GC-MS)结合电子鼻(Electronic Nose,E-nose)技术对西南、华南、江南三大茶区的8种茉莉花茶进行香气研究。结果表明,8个样品共鉴定出香气成分58... 为探究不同产区茉莉花茶香气差异,采用气相色谱-质谱(GasChromatography-Mass Spectrometry,GC-MS)结合电子鼻(Electronic Nose,E-nose)技术对西南、华南、江南三大茶区的8种茉莉花茶进行香气研究。结果表明,8个样品共鉴定出香气成分58种,其中西南、江南、华南茶区分别为45种、51种、47种。江南茶区香气化合物总量最高。共有香气成分主要包括邻氨基苯甲酸甲酯、顺式-3-己烯醇苯甲酸酯、乙酸苄酯、水杨酸甲酯、芳樟醇、吲哚等。其中水杨酸甲酯在江南茶区含量最高(22.32μg/g),分别较华南、西南茶区高33.96%、68.01%;邻氨基苯甲酸甲酯(67.39μg/g)和吲哚(43.84μg/g)含量在华南茶区最高。茉莉花茶香气评价指数(JasmineTea Flavor Index,JTF index)分析表明西南茶区样品等级最高。香气聚类分析将共有香气成分分为3类,分别呈花香、茉莉花香和草木香。通过电子鼻技术可知样品香气物质变化与硫化物、碳氢化合物、芳香化合物有关,并能有效区别样品香气。综上,三大茶区样品香气种类差异不明显,但各香气成分含量差异显著(P<0.05),江南和华南茶区的样品特征性香气成分含量较高,西南茶区样品综合指数高。 展开更多
关键词 香气 茉莉花茶 气相色谱-质谱法(GC-MS) 电子鼻 茉莉花茶香气评价指数(JTF index)
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Metamorphic Manipulating Mechanism Design for MCCB Using Index Reduced Iteration 被引量:5
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作者 XU Jinghua ZHANG Shuyou +1 位作者 ZHAO Zhen LIN Xiaoxia 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第2期232-241,共10页
The present research on moulded case circuit breaker(MCCB) focuses on the enhancement of current-limiting interrupting performance during short circuit, overload, under voltage and phase failure, involving electrics... The present research on moulded case circuit breaker(MCCB) focuses on the enhancement of current-limiting interrupting performance during short circuit, overload, under voltage and phase failure, involving electrics, magnetic, mechanics, thermal, material, friction, arc extinguishing, impact vibration, skin effect, etc. The rigid-flexible coupling of the parts and components of the metamorphic manipulating mechanism in multi-fields leads to the non-rigid, high frequency, high damping, singularity of the Euler-Lagrange equations which represents the multi-body dynamics. The small step iteration which is used for obtaining the instantaneous and short time critical interrupting performance of metamorphic mechanism appears inaccuracy. It is difficult to realize top-down design by existing CAD systems. Therefore, a metamorphic manipulating mechanism design method for MCCB using index reduced iteration(IRI) is put forward. The metamorphic manipulating mechanism of MCCB is decomposed into three mechanisms: main switch connector mechanism, electromagnet-drawbar-jump buckle mechanism, and bimetallic strip-drawbar mechanism, which is respectively described by electro-dynamic force, electromagnet force, and bimetallic strip force. The dummy part(virtual rigid) without moment of inertia and mass is employed as intermediate to join the flexible body and rigid body. The model of rigid-flexible coupling metamorphic mechanism multi-body dynamics is built. The differential algebraic equations(DAEs) of the multibody dynamics model are converted to pure ordinary differential equations(ODEs) by coordinate partition. Order reduced integration with multi-step and variable step-size is preceded based on IRI. The non-linear algebraic equations are solved in each integration step by Newton-Rapson iteration. There is no ill-condition and singularity of Jacobian matrix when step size reduces to zero. The independent prototype design system using ACIS R13, HOOPS V11.0 and Visual C++.NET 2003 has been developed, which verifies the effectiveness of the proposed method. The proposed method enhances the current-limiting interrupting performance of MCCB, and has reference significance for multi-body dynamics design for similar flexible metamorphic mechanisms in multi-fields. 展开更多
关键词 index reduced iteration (IRI) moulded case circuit breaker (MCCB) metamorphic manipulating mechanism Euler-Lagrange equations rigid-flexible coupling multi-body dynamics current interrupting simulation
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Analysis and Design of the Globoidal Indexing Cam Mechanism 被引量:3
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作者 FU Yan ming School of Mechanical and Electronic Engineering and Automation, Shanghai University, Shanghai 200072, China 《Advances in Manufacturing》 2000年第1期54-59,共6页
We first design and analyze the contour surface of the globoidal indexing cam with the aid of computer, and then do optimum design according to the requirements of dynamics. Finally, we discuss the problem of the pres... We first design and analyze the contour surface of the globoidal indexing cam with the aid of computer, and then do optimum design according to the requirements of dynamics. Finally, we discuss the problem of the pressure angle of the globoidal indexing cam mechanism in detail and put forward a new concept of equivalent pressure angle. 展开更多
关键词 globoidal indexing cam analysis of cam mechanism design of cam mechanism dynamics of mechanism pressure angle
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An Assessment of Heavy-Metal Contamination in Soils within Auto-Mechanic Workshops Using Enrichment and Contamination Factors with Geoaccumulation Indexes 被引量:4
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作者 Isaac A. Ololade 《Journal of Environmental Protection》 2014年第11期970-982,共13页
Soil characterization and heavy metals in different layers (0 - 15 cm;15 - 30 cm and 30 - 45 cm depth) of automobile mechanic waste dumps were studied. The soils showed remarkably high levels of all the metals above b... Soil characterization and heavy metals in different layers (0 - 15 cm;15 - 30 cm and 30 - 45 cm depth) of automobile mechanic waste dumps were studied. The soils showed remarkably high levels of all the metals above background concentrations with most (Ni, Cu, Fe, Cr and Cd) decreasing with soil depth. The distribution pattern were in the following order Fe > Cu > Zn > Pb > Cr > Ni > Cd. Across all the sampling locations and profiles, Fe and Cd showed the highest (476.4 μg·g-1) and least (37.5 μg·g-1) mean concentrations respectively. Pollution load index (PLI) and index of geoaccumulation (Igeo) revealed overall high and moderate contamination respectively but the enrichment factors (EFs) for Pb Ni and Cd are severe. The inter-element relationship revealed the identical source of elements in the soils of the studied area. The accuracy of the results has been cheeked using the standard reference material;SRM (PACS-2). The mechanic waste dumps represent potential sources of heavy metal pollution to environment. The elevated levels of heavy metals in these soil profiles constitute a serious threat to both surface and groundwater. 展开更多
关键词 HEAVY Metals SOIL CONTAMINATION SOIL Profiles Automobile mechanIC ENRICHMENT Factor Geoaccumulation index
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A Parallel Indexing Cam Mechanism with Internal Placed Followers 被引量:1
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作者 ZHANG Yuhua REN Guangfa (School of Mechanical Engineering,Anhui University of Technology,Ma’anshan 243002,China 《武汉理工大学学报》 CAS CSCD 北大核心 2006年第S2期533-537,共5页
A new type of parallel indexing cam mechanism is discovered.The composition of the cam profile is proposed and the formulas of the mechanism parameters are established by synthesis of its configuration and size.The eq... A new type of parallel indexing cam mechanism is discovered.The composition of the cam profile is proposed and the formulas of the mechanism parameters are established by synthesis of its configuration and size.The equations for working pro- file and pressure angle of the cam are derived based on the inverse model and the derivative of pitch curve of cams.An example is given and demonstrates that it is available to design the new mechanism using the derived expressions. 展开更多
关键词 CAM mechanism PARALLEL indexING CAM INTERNAL CAM mechanism synthesis INTERNAL placed FOLLOWERS
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Evaluation method for assessing the auxiliary service transaction mechanism in regional power markets
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作者 Le Liu Xueyu Chen +3 位作者 Dexin Li Chang Liu Dunnan Liu Genzhu Li 《Global Energy Interconnection》 EI CAS CSCD 2023年第2期238-252,共15页
Accurate and seamless auxiliary services in the power market can guarantee smooth and continuous power system operation. China’s new round of power system reform has entered a critical period, and reform implementati... Accurate and seamless auxiliary services in the power market can guarantee smooth and continuous power system operation. China’s new round of power system reform has entered a critical period, and reform implementation requires comprehensive improvements in the maturity of the supporting auxiliary service market. This study reviews the development status and evolution path of the European unified power market and the US regional power market, provides experience for the development of China’s regional power market, then identifies the key influencing factors of auxiliary service trading mechanism design in regional power markets. To analyze the rationality of the auxiliary service trading evaluation index, this paper established an evaluation model for assessing regional power markets. Using combined weight optimization, the gray correlation TOPSIS method was applied to comprehensively evaluate auxiliary service trading in the regional power market. Finally, the application of the proposed evaluation method was briefly analyzed to examine four regional power markets in China and evaluate the effectiveness of current market construction in different regions and provide suggestions for future market construction. 展开更多
关键词 Power market Auxiliary services Transaction mechanism Evaluation index Evaluation model
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基于Wnt 5a/β-catenin信号通路探讨杜仲健骨方对骨质疏松症大鼠的治疗作用 被引量:2
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作者 刘嵬 王文志 +2 位作者 李志永 郝从强 宗雅琪 《辽宁中医杂志》 CAS 北大核心 2024年第1期201-205,共5页
目的探究不同剂量杜仲健骨方对骨质疏松症模型大鼠骨力学参数的影响及对Wnt5a/β-catenin信号通路的干预作用。方法60只SD大鼠分为对照组、模型组、杜仲健骨方低剂量组、杜仲健骨方中剂量组和杜仲健骨方高剂量组,采用去势(摘除大鼠双侧... 目的探究不同剂量杜仲健骨方对骨质疏松症模型大鼠骨力学参数的影响及对Wnt5a/β-catenin信号通路的干预作用。方法60只SD大鼠分为对照组、模型组、杜仲健骨方低剂量组、杜仲健骨方中剂量组和杜仲健骨方高剂量组,采用去势(摘除大鼠双侧卵巢)制备骨质疏松症大鼠模型,对照组仅翻动两侧卵巢,不做其他处理。造模成功后杜仲健骨方各处理组分别给予低、中、高计量的杜仲健骨方灌胃90 d,实验终点检测大鼠骨密度、骨生物力学指标,骨形态学指标;通过Elisa法检测各组大鼠血清中抗酒石酸碱性磷酸酶(TRAP)、尿I型胶原交联N末端肽(U-NTX)、骨碱性磷酸酶(BALP)、雌二醇(E2)、尿型胶原交联C末端肽(U-CTX)、骨钙蛋白(BGP)等骨转化指标;通过qPCR和Western blot法检测骨组织中Wnt5a/β-catenin通路分子的mRNA和蛋白表达水平。结果杜仲健骨方能显著增加骨质疏松大鼠股骨、脊柱骨的骨密度(P<0.01),提高股骨生物力学参数水平(P<0.01);增加皮质骨面积百分比、骨小梁平均厚度、骨小梁面积、骨小梁体积(P<0.01),增加血清中的BALP、E2水平(P<0.01),降低血清中的BGP、TRAP、U-NTX、U-CTX水平(P<0.01);显著增加Wnt5a/β-catenin通路分子的mRNA和蛋白表达水平(P<0.01)。结论杜仲健骨方可以提高骨质疏松大鼠骨力学参数,并且调控Wnt5aβ-catenin信号通路,有利于骨质疏松症的治疗。 展开更多
关键词 杜仲健骨方 骨力学参数 骨代谢指标 骨质疏松症 Wnt5a/β-catenin通路
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Hot deformation behavior and globularization mechanism of Ti-6Al-4V-0.1B alloy with lamellar microstructure 被引量:7
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作者 Yang Yu Bai-Qing Xiong +1 位作者 Song-Xiao Hui Wen-Jun Ye 《Rare Metals》 SCIE EI CAS CSCD 2013年第2期122-128,共7页
Hot deformation behavior and globularization mechanism of Ti6A14V0.1B alloy with lamellar micro structure were quantitatively studied through isothermal compression tests with the temperature range of 850950 ℃and str... Hot deformation behavior and globularization mechanism of Ti6A14V0.1B alloy with lamellar micro structure were quantitatively studied through isothermal compression tests with the temperature range of 850950 ℃and strain rate range of 0.011.00 s1. The results show that the peak flow stress and steady stress are sensitive to the strain rate and temperature. The value of deformation activation energy is 890.49 kJmo11 in (a+β) region. Dynamic recrystallization is the major deformation mecha nism. Flow softening is dominated by dynamic recrystallization at 850950 ℃. TiB particles promote the recrystallization of laths. Globularization processes consist of four steps: for mation of subgrain after dynamic recovery in a plates; subgrain boundary migration caused by interracial instability; interfacial migration promoting phase wedge into a phase; disintegrating of a laths by diffusion processes; and grain boundary sliding. Globularization mechanisms during hot deformation processes of the Ti6A14V0.1B alloy with lamellar structure are continuous dynamic recrystallization. 展开更多
关键词 Ti-6A1-4V-0.1B Hot deformation Lamellarmicrostructure Globularization mechanism
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Adsorption and flotation mechanism of a ketoxime-dithiocarbonate surfactant to chalcopyrite 被引量:3
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作者 XIAO Jing-jing YAO Chen +1 位作者 WU Ya-xin LI Chang-zhu 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第12期3847-3857,共11页
The adsorption mechanism of O-isopropyl-S-[2-(hydroxyimino) propyl] dithiocarbonate ester(IPXPO) to chalcopyrite was investigated by using contact angle, in-situ atomic force microscopy(in-situ AFM), cyclic voltammetr... The adsorption mechanism of O-isopropyl-S-[2-(hydroxyimino) propyl] dithiocarbonate ester(IPXPO) to chalcopyrite was investigated by using contact angle, in-situ atomic force microscopy(in-situ AFM), cyclic voltammetry(CV) and X-ray photoelectron spectroscopy(XPS). The results of contact angle and in-situ AFM demonstrated that IPXPO adsorbed on chalcopyrite increases surface hydrophobicity and roughness. It was found by CV experiments that a layer passive film was formed. The results of XPS spectra further revealed that the thiol S atom, oxime N atom, and O atom in the IPXPO molecule might react with copper atoms to form Cu-S, Cu-N, and Cu-O bonds, respectively. An artificial mixed minerals flotation test indicated that under the condition of pH=6.79 and IPXPO initial concentration 5×10^(-5)mol/L, the flotation recovery of chalcopyrite reached about 90%, while for pyrite only 25%, suggesting that IPXPO is an excellent collector for flotation separation and enrichment of chalcopyrite. 展开更多
关键词 O-isopropyl-S-[2-(hydroxyimino)propyl]dithiocarbonate ester CHALCOPYRITE HYDROPHOBICITY adsorption mechanism FLOTATION
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A Further Inquiry on the Mechanism of 30-60 Day Oscillation in the Tropical Atmosphere 被引量:20
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作者 李崇银 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1993年第1期41-53,共13页
In a simple semi-geostropic model on the equatorial β-plane, the theoretical analysis on the 30-60 day oscillation in the tropical atmosphere is further discussed based on the wave-CISK mechanism. The convection heat... In a simple semi-geostropic model on the equatorial β-plane, the theoretical analysis on the 30-60 day oscillation in the tropical atmosphere is further discussed based on the wave-CISK mechanism. The convection heating can excite the CISK-Kelvm wave and CISK-Rossby wave in the tropical atmosphere and they are all the low-frequency modes which drive the activities of 30-60 day oscillation in the tropics. The most favorable conditions to excite the CISK-Kelvin wave and CISK-Rossby wave are indicated: There is convection heating but not very strong in the atmosphere and there is weaker disturbance in the lower troposphere.The influences of vertical shearing of basic flow in the troposphere on the 30-60 day oscillation in the tropics are also discussed. 展开更多
关键词 A Further Inquiry on the mechanism of 30-60 Day Oscillation in the Tropical Atmosphere
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Algebraic Solution for the Forward Displacement Analysis of the General 6-6 Stewart Mechanism 被引量:8
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作者 WEI Feng WEI Shimin +1 位作者 ZHANG Ying LIAO Qizheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第1期56-62,共7页
The solution for the forward displacement analysis(FDA) of the general 6-6 Stewart mechanism(i.e., the connection points of the moving and fixed platforms are not restricted to lying in a plane) has been extensive... The solution for the forward displacement analysis(FDA) of the general 6-6 Stewart mechanism(i.e., the connection points of the moving and fixed platforms are not restricted to lying in a plane) has been extensively studied, but the efficiency of the solution remains to be effectively addressed. To this end, an algebraic elimination method is proposed for the FDA of the general 6-6 Stewart mechanism. The kinematic constraint equations are built using conformal geometric algebra(CGA). The kinematic constraint equations are transformed by a substitution of variables into seven equations with seven unknown variables. According to the characteristic of anti-symmetric matrices, the aforementioned seven equations can be further transformed into seven equations with four unknown variables by a substitution of variables using the Grobner basis. Its elimination weight is increased through changing the degree of one variable, and sixteen equations with four unknown variables can be obtained using the Grobner basis. A 40th-degree univariate polynomial equation is derived by constructing a relatively small-sized 9 × 9 Sylvester resultant matrix. Finally, two numerical examples are employed to verify the proposed method. The results indicate that the proposed method can effectively improve the efficiency of solution and reduce the computational burden because of the small-sized resultant matrix. 展开更多
关键词 general 6-6 Stewart mechanism forward displacement analysis (FDA) conformal geometric algebra (CGA) Gr6bner basis Sylvester resultant
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Stability evaluation method of large cross-section tunnel considering modification of thickness-span ratio in mechanized operation
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作者 Junru Zhang Yumeng Liu Bo Yan 《Railway Sciences》 2023年第2期197-210,共14页
Purpose-This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.Design/methodology/approach-First,taking the Liuyuan Tunnel of Huangg... Purpose-This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.Design/methodology/approach-First,taking the Liuyuan Tunnel of Huanggang-Huangmei High-Speed Railway as an example and taking deflection of the third principal stress of the surrounding rock at a vault after tunnel excavation as the criterion,the critical buried depth of the large section tunnel was determined.Then,the strength reduction method was employed to calculate the tunnel safety factor under different rock classes and thickness-span ratios,and mathematical statistics was conducted to identify the relationships of the tunnel safety factor with the thickness-span ratio and the basic quality(BQ)index of the rock for different rock classes.Finally,the influences of thickness-span ratio,groundwater,initial stress of rock and structural attitude factors were considered to obtain the corrected BQ,based on which the stability of a large cross-section tunnel with a depth of more than 100 m during mechanized operation was analyzed.This evaluation method was then applied to Liuyuan Tunnel and Cimushan No.2 Tunnel of Chongqing Urban Expressway for verification.Findings-This study shows that under different rock classes,the tunnel safety factor is a strict power function of the thickness-span ratio,while a linear function of the BQ to some extent.It is more suitable to use the corrected BQ as a quantitative index to evaluate tunnel stability according to the actual conditions of the site.Originality/value-The existing industry standards do not consider the influence of buried depth and span in the evaluation of tunnel stability.The stability evaluation method of large section tunnel considering the correction of overburden span ratio proposed in this paper achieves higher accuracy for the stability evaluation of surrounding rock in a full or large-section mechanized excavation of double line high-speed railway tunnels. 展开更多
关键词 Large cross-section tunnel mechanized operation Tunnel stability Thickness-span ratio Basic quality index of rock Safety factor DEPTH SPAN
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Mechanical Property and Microstructure of Cement Mortar with Carbonated Recycled Powder
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作者 丁亚红 张美香 +3 位作者 YANG Xiaolin XU Ping SUN Bo GUO Shuqi 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第3期689-697,共9页
Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbon... Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbonation methods was tested through XRD and SEM,the mechanical property and microstructure of recycled powder mortar with three replacement rates were studied by ISO method and SEM,and the strengthening mechanism was analyzed.The results showed that the mechanical property of recycled powder mortar decreased with the increasing of replacement rate.It is suggested that the replacement rate of recycled powder should not exceed 20%.The strength index and activity index of carbonated recycled powder mortar were improved,in which the flexural strength was increased by 27.85%and compressive strength was increased by 20%at the maximum.Recycled powder can be quickly and completely carbonated,and the improvement effect of CH pre-soaking carbonation was the best.The activity index of carbonated recycled powder can meet the requirements of Grade II technical standard for recycled powder.Microscopic results revealed the activation mechanism of carbonated recycled powder such as surplus calcium source effect,alkaline polycondensation effect and carbonation enhancement effect. 展开更多
关键词 recycled powder carbonation activation compound carbonation activity index mechanical property MICROSTRUCTURE
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基于BiLSTM-Attention的F_(10.7)指数预测模型与中国自主数据集的应用
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作者 闫帅楠 李雪宝 +7 位作者 董亮 黄文耿 王晶 闫鹏朝 娄恒瑞 黄徐胜 李哲 郑艳芳 《空间科学学报》 CAS CSCD 北大核心 2024年第2期251-261,共11页
F_(10.7)指数是太阳活动的重要指标,准确预测F_(10.7)指数有助于预防和缓解太阳活动对无线电通信、导航和卫星通信等领域的影响.基于F_(10.7)射电流量的特性,在双向长短时记忆网络(Bidirectional Long Short-Term Memory Network,BiLSTM... F_(10.7)指数是太阳活动的重要指标,准确预测F_(10.7)指数有助于预防和缓解太阳活动对无线电通信、导航和卫星通信等领域的影响.基于F_(10.7)射电流量的特性,在双向长短时记忆网络(Bidirectional Long Short-Term Memory Network,BiLSTM)基础上融入注意力机制(Attention),提出了一种基于BiLSTM-Attention的F_(10.7)预报模型.在加拿大DRAO数据集上其平均绝对误差(MAE)为5.38,平均绝对百分比误差(MAPE)控制在5%以内,相关系数(R)高达0.987,与其他RNN模型相比拥有优越的预测性能.针对中国廊坊L&S望远镜观测的F_(10.7)数据集,提出了一种转换平均校准(Conversion Average Calibration,CAC)方法进行数据预处理,处理后的数据与DRAO数据集具有较高的相关性.基于该数据集对比分析了RNN系列模型的预报效果,实验结果表明,BiLSTM-Attention和BiLSTM两种模型在预测F_(10.7)指数方面具有较好的优势,表现出较好的预测性能和稳定性. 展开更多
关键词 F_(10.7)预报 双向长短时记忆网络 注意力机制 L&S数据集
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Influence of gas transport mechanisms on the productivity of multi-stage fractured horizontal wells in shale gas reservoirs 被引量:1
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作者 Wei Wang Jun Yao +1 位作者 Hai Sun Wen-Hui Song 《Petroleum Science》 SCIE CAS CSCD 2015年第4期664-673,共10页
In order to investigate the influence on shale gas well productivity caused by gas transport in nanometer- size pores, a mathematical model of multi-stage fractured horizontal wells in shale gas reservoirs is built, w... In order to investigate the influence on shale gas well productivity caused by gas transport in nanometer- size pores, a mathematical model of multi-stage fractured horizontal wells in shale gas reservoirs is built, which considers the influence of viscous flow, Knudsen diffusion, surface diffusion, and adsorption layer thickness. A dis- crete-fracture model is used to simplify the fracture mod- cling, and a finite element method is applied to solve the model. The numerical simulation results indicate that with a decrease in the intrinsic matrix permeability, Knudsen diffusion and surface diffusion contributions to production become large and cannot be ignored. The existence of an adsorption layer on the nanopore surfaces reduces the effective pore radius and the effective porosity, resulting in low production from fractured horizontal wells. With a decrease in the pore radius, considering the adsorption layer, the production reduction rate increases. When the pore radius is less than 10 nm, because of the combined impacts of Knudsen diffusion, surface diffusion, and adsorption layers, the production of multi-stage fractured horizontal wells increases with a decrease in the pore pressure. When the pore pressure is lower than 30 MPa, the rate of production increase becomes larger with a decrease in pore pressure. 展开更多
关键词 Shale gas - Transport mechanisms ~Numerical simulation - Fractured horizontal wellProduction
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