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Polycrystalline model for FE-simulation of micro forming processes 被引量:3
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作者 王春举 郭斌 单德彬 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第6期1362-1366,共5页
A new polycrystal model was presented from the viewpoint of polycrystal structure of the billets considering free surface effects.In the model,the billet was divided into three portions,such as free surface portion,tr... A new polycrystal model was presented from the viewpoint of polycrystal structure of the billets considering free surface effects.In the model,the billet was divided into three portions,such as free surface portion,transition portion and internal portion.The grains in free surface portion were considered the single grains,and the anisotropy of the grains was taken into account by introducing grain orientation to explain the inhomogeneous deformation.In the transition portion,the effects of the neighbouring grains were adopted in the model.The grains in the internal portion were considered the polycrystalline material.With the developed model,the upsetting deformation process was simulated by the MSC Superform software.The scatter of the flow stress and inhomogeneous deformation was observed by analysis of the model.The comparisons show that the computational results are good agreed with the experimental results.This means that the presented model is effective. 展开更多
关键词 micro forming size effect polycrystal model inhomogeneous deformation
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Constitutive model for thin sheet metal with one or several grains across thickness in micro-forming
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作者 王倩 董湘怀 +2 位作者 章海明 李河宗 申昱 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第5期1428-1434,共7页
Effects of four factors on thin sheet metal flow stress were considered, including grain size d, thickness t, grain number across thickness (t/d ratio) and surface property. Surface model was adopted to quantitative... Effects of four factors on thin sheet metal flow stress were considered, including grain size d, thickness t, grain number across thickness (t/d ratio) and surface property. Surface model was adopted to quantitatively describe the effect of t/d ratio on flow stress for pure copper. It is predicted that when t/d ratio is larger than a critical value, effect of t/d ratio on flow stress can be neglected. Existence of critical t/d ratio changes the Hall-Petch relationship and evolution of flow stress with thickness. A criterion was proposed to determine critical t/d ratio. Then a comprehensive constitutive model was developed to consider all the four factors, with parameters determined by fitting experimental data of high purity Ni. The predicted results show the same tendencies with experiment results. Particularly when t/d ratio decreases, Hall-Petch relationship and evolution of true stress show varied slopes with two transition points. 展开更多
关键词 constitutive model flow stress micro forming size effect
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Microstructure and properties of Al-0.70Fe-0.24Cu alloy conductor prepared by horizontal continuous casting and subsequent continuous extrusion forming 被引量:6
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作者 张晓苑 张辉 +1 位作者 孔祥鑫 傅定发 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第6期1763-1769,共7页
A novel process for manufacturing A1-0.70Fe-0.24Cu alloy conductor was proposed, which includes horizontal continuous casting and subsequent continuous extrusion forming (Conform). The mechanical properties, electri... A novel process for manufacturing A1-0.70Fe-0.24Cu alloy conductor was proposed, which includes horizontal continuous casting and subsequent continuous extrusion forming (Conform). The mechanical properties, electrical conductivity and the compressed creep behaviour of the alloy were studied. The results indicate that the Conform process induces obvious grain refinement, strain-induced precipitation of AI7CuzFe phase and the transformation of crystal orientation distribution. The processed alloy has good comprehensive mechanical properties and electrical conductivity. Moreover, a better creep resistance under the conditions of 90 ~C and 76 MPa is shown compared with pure A1 and annealed copper, and the relationship between primary creep strain and time may comply with the logarithmic law. The enhanced properties are attributed to the grain refinement as well as the fine and homogeneously distributed thermally stable A1Fe and A17Cu2Fe precipitation phases. 展开更多
关键词 A1-0.70Fe-0.24Cu alloy horizontal continuous casting continuous extrusion forming microSTRUCTURE PROPERTY
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Crystal Plasticity Finite Element Process Modeling for Hydro-forming Micro-tubular Components 被引量:4
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作者 ZHUANG Weimin WANG Shiwen +1 位作者 BALINT Daniel LIN Jianguo 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第1期78-83,共6页
Micro-tubes manufactured by hydro-forming techniques have now been widely used in medical and microelectronics applica- tions. One of the difficulties in forming such parts is the control of localized necking in the i... Micro-tubes manufactured by hydro-forming techniques have now been widely used in medical and microelectronics applica- tions. One of the difficulties in forming such parts is the control of localized necking in the initial stages of the deformation/forming process. A lack of microstructural information causes conventional macro-mechanics finite element(FE) tools to break down when used to investigate the localized microstructure evolution and necking encountered in micro-forming. An effort has been made to create an integrated crystal plasticity finite element(CPFE) system that enables micro-forming process simulations to be carried out easily, with the important features in forming micro-parts captured by the model. Based on Voronoi tessellation and probability theory, a virtual GRAIN(VGRAIN) system is created for generating grains and grain boundaries for micro-materials. Numerical procedures are devel- oped to link the physical parameters of a material to the control variables in a Gamma distribution. A script interface is developed so that the virtual microstructure can be input to the commercial FE code, ABAQUS, for mesh generation. A simplified plane strain CPFE modeling technique is developed and used to capture localized thinning and failure features for hydro-forming of micro-tubes. Grains within the tube workpiece, their distributions and orientations are generated automatically by using the VGRAIN system. A set of crystal viscoplasticity constitutive equations are implemented in ABAQUS/Explicit by using the user-defined material subroutine, VUMAT. Lo- calized thinning is analyzed for different microstructures and deformation conditions of the material using the CPFE modeling technique. The research results show that locations of thinning in forming micro-tubes can be random, which are related to microstructure and grain orientations of the material. The proposed CPFE technique can be used to predict the locations of thinning in forming micro-tubes. 展开更多
关键词 micro-mechanics modeling micro-forming hydro-forming
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Hybrid Micro-forming Processes and Quality Evaluation of Micro-double Gear 被引量:1
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作者 徐杰 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第S1期90-94,共5页
Micro-gear is an important actuating component used widely in the micro electro mechanical systems(MEMS) devices.The technologies of micro-forming and precision assembly are urgently developed to manufacture the micro... Micro-gear is an important actuating component used widely in the micro electro mechanical systems(MEMS) devices.The technologies of micro-forming and precision assembly are urgently developed to manufacture the micro-double gear with central shaft.In the paper,a novel hy-brid-forming process with two kinds of piercing method have been proposed to manufacture the micro-double gear using micro forming technology.The tests of hybrid forming process were carried out with two steps and the micro-double gear was successfully manufactured with good surface quality.The results also show that the hybrid micro-forming process with central piercing method can improve the defects of inclining shaft generated by double-ended piercing method.The quality evaluation of micro-double gear was conducted with surface roughness,micro-hardness and impact tests.The results show that the micro-double gear with good mechanical properties can meet the requirements of application for milli-machines. 展开更多
关键词 micro-forming hybrid forging process quality evaluation micro-double gear
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Influence of Pore Forming Agent on Properties of Micro-pored CA_6-MA Material
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作者 LI Chunming ZHOU Ningsheng BI Yubao 《China's Refractories》 CAS 2013年第2期24-28,共5页
Micro-pored CA6 -MA lightweight material with CAM: MA mass ratio of 7:3 was prepared using Al(OH) 3, MgCO3 and CaCO3 as starting materials, and anthracite. sweet potato starch and anthracite + sweet potato starch... Micro-pored CA6 -MA lightweight material with CAM: MA mass ratio of 7:3 was prepared using Al(OH) 3, MgCO3 and CaCO3 as starting materials, and anthracite. sweet potato starch and anthracite + sweet potato starch as pore forming agent (PFA) with an addition of 10 mass%, 20 mass% and 30 mass%, respectively. The starting materials were dry mixed, wet co-milled in a ball mill for 1 h. slip cast into cylindrical specimens with a diameter of 60 ram. and then calcined at 1 450 ℃ for 3 h. With the increase of PFA addition,, apparent porosity increases, and bulk density decreases. The influence of different PFAs on properties of the micro-pored LW CAM -MA aggregate was investigated. The achieved CAM - MA, by adding 30% sweet potato starch, has a porosity of 76. 8%, bulk density of 0. 78 g · cm^ - 3 and median pore size of 1.90 μm. 展开更多
关键词 micro-pored material calcium hexaluminate spinel pore forming agent lightweight aggregate refractory
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Wrinkling prediction in rubber forming of Ti-15-3 alloy 被引量:4
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作者 孙永娜 万敏 吴向东 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第10期3002-3010,共9页
Wrinkling is a common failure in the sheet metal forming of titanium owing to the relatively poor ability to shrink. It is important to predict wrinkling accurately in the sheet metal forming without costly trials. Th... Wrinkling is a common failure in the sheet metal forming of titanium owing to the relatively poor ability to shrink. It is important to predict wrinkling accurately in the sheet metal forming without costly trials. The ABAQUS/Explicit code was utilized to predict the wrinkling behavior in the sheet metal forming of Ti-15-3 alloy sheets. In terms of the comparison of wrinkling behavior between the simulation and experiment of the Fukui's conical cup tests at room temperature, the sensitivities of wrinkling simulation to various input parameters were evaluated comprehensively and quantitatively. Prediction of wrinkling and influence of rubber hardness on the winkling behavior in the rubber forming of convex flange were investigated quantitatively and validated by the rubber forming experiments. The excellent agreements between the simulations and the experiments conIirmed the accuracy of the prediction. 展开更多
关键词 Ti-15-3 alloy WRINKLING convex flange rubber forming quantitative analysis
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Friction coefficient in rubber forming process of Ti-15-3 alloy 被引量:4
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作者 孙永娜 万敏 吴向东 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第12期2952-2959,共8页
The forming limit diagram of Ti-15-3 alloy sheet was constituted at room temperature. The effects of different punch and rubber hardness on the limit principal strain distributions were investigated experimentally. Fi... The forming limit diagram of Ti-15-3 alloy sheet was constituted at room temperature. The effects of different punch and rubber hardness on the limit principal strain distributions were investigated experimentally. Finite element analysis models of the samples with dimensions of 180 mm×180 mm were established to analyze the friction coefficients of different interfaces. Effects of various friction coefficients on the strain distributions were studied in detail. Finally, the friction coefficients in the cold forming were determined by contrasting the strain results between the experimental data and the simulated ones. 展开更多
关键词 Ti-15-3 alloy rubber forming FRICTION BULGING principal strain finite element analysis
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3003Al-H14薄壁微小通道扁管波形冲压成形尺寸对截面变形的作用规律
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作者 程传峰 金明 +4 位作者 王项如 朱英霞 程一峰 盘朝奉 王园 《中国材料进展》 CAS CSCD 北大核心 2024年第3期265-272,共8页
薄壁微小通道波形扁管是建设新能源汽车锂电池组恒温系统的绝佳材料,成形尺寸是影响其冲压成形截面变形的关键因素。建立了实验验证的3003Al-H14微小通道薄壁扁管的波形冲压-回弹有限元模型。基于所建模型,研究了截面高度、管坯壁厚、... 薄壁微小通道波形扁管是建设新能源汽车锂电池组恒温系统的绝佳材料,成形尺寸是影响其冲压成形截面变形的关键因素。建立了实验验证的3003Al-H14微小通道薄壁扁管的波形冲压-回弹有限元模型。基于所建模型,研究了截面高度、管坯壁厚、内外面相对弯曲半径缩放系数等成形尺寸,对截面变形率和平均截面变形率的作用规律。研究发现:①横截面上边缘孔的截面变形率通常较大,其余孔的截面变形率相对较小且大小一致;纵截面上孔的截面变形率呈现波峰波谷高、中间段低的分布特点。②扁管的截面变形率随着截面高度增大而增大,当截面高度超过4 mm时,扁管内的筋显著弯折,横截面塌陷严重。③扁管的平均截面变形率随着壁厚增大呈指数函数下降;当壁厚等于0.1 mm时,所有截面都畸变严重,而当壁厚超过0.3 mm时,最大截面畸变率下降至24.71%。④内外面相对弯曲半径的缩放系数越大,则内外面的实际弯曲程度越小,平均截面变形率也越小。研究成果对薄壁微小通道波形扁管的精确成形具有科学意义和工程价值。 展开更多
关键词 微小通道管 冲压 薄壁件 成形尺寸 截面变形
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Glass-forming ability and crystallization of Mg-Ni amorphous alloys with Y addition 被引量:8
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作者 Liu Liyan Teng Xinying +1 位作者 Wang Yongjie Liu Teng 《Rare Metals》 SCIE EI CAS CSCD 2012年第3期244-249,共6页
Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) amorphous alloys were obtained by single-roller melt-spinning technique and the effect of Y addition on the glass forming ability(GFA), crystallization and micro-hardness of Mg-Ni ... Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) amorphous alloys were obtained by single-roller melt-spinning technique and the effect of Y addition on the glass forming ability(GFA), crystallization and micro-hardness of Mg-Ni alloys were studied. The results show that the GFA of Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) is improved successfully with the Y addition. The highest GFA appeares at x=6, while the reduced glass transition temperature (Trg) is 0.5225 and the supercooled liquid region(ΔTx) is 42.06 K; the position of the main diffraction halo is different for the alloys, and the maximum of the main diffraction halo of alloys with x=0, 1, 3 corresponds to the main peaks of a metastable fcc-Mg6Ni or fcc-Mg6Ni + Ni-Y intermetallic phases, and for the alloys with x=6, 10, it corresponds to Mg-Y and Ni-Y intermetallic phases; the micro-hardness of the alloys is improved with Y additions, and the highest micro-hardness is obtained at x=6 at.%, which is 960 MPa. 展开更多
关键词 Mg-based amorphous alloy glass forming ability CRYSTALLIZATION micro-hardness
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Unveiling the planar deformation mechanisms for improved formability in pre-twinned AZ31 Mg alloy sheet at warm temperature
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作者 Xiaohuan Pan Lifei Wang +8 位作者 Pengbin Lu Hua Zhang Guangsheng Huang Liuwei Zheng Bin Xing Weili Cheng Hongxia Wang Wei Liang Kwang Seon Shin 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第12期4659-4678,共20页
To investigate the role of pre-twins in Mg alloy sheets during warm planar deformation,the stretch forming is conducted at 200℃.Results suggest the formability of the pre-twinned AZ31 Mg alloy sheet is enhanced to 11... To investigate the role of pre-twins in Mg alloy sheets during warm planar deformation,the stretch forming is conducted at 200℃.Results suggest the formability of the pre-twinned AZ31 Mg alloy sheet is enhanced to 11.30 mm.The mechanisms for the improved formability and the deformation behaviors during the planar stretch forming are systematically investigated based on the planar stress states.The Schmid factor for deformation mechanisms are calculated,the results reveal that planar stress states extremely affect the Schmid factor for{10-12}twinning.The detwinning is activated and the prismatic slip is enhanced in the pre-twinned sheet,especially under the planar extension stress state in the outer region.Consequently,the thickness-direction strain is accommodated better.The dynamic recrystallization(DRX)type is continuous DRX(CDRX)regardless of the planar stress state.However,the CDRX degree is greater under the planar extension stress state.Some twin lattices deviate from the perfect{10-12}twinning relation due to the planar compression stress state and the CDRX.The basal texture is weakened when the planar stress state tends to change the texture components. 展开更多
关键词 AZ31 Mg alloy sheet Planar stretch forming Planar stress states Continuous dynamic recrystallization {10-12}tensile twinning
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Influence of arc pressure on the forming of molten pool in tungsten inert gas arc butt welding with micro gap for tantalum sheet
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作者 周方明 钱乙余 《China Welding》 EI CAS 2006年第3期64-67,共4页
Arc pressure is the key influencing factor to forming of molten pool. Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a dis... Arc pressure is the key influencing factor to forming of molten pool. Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a distribution model of arc pressure and forming mechanism of molten pool with micro butt gap are proposed, and the influences of arc pressure on forming of molten pool are discussed. Experimental researches for the dynamic formation process of weld molten pool by using high-speed vidicon camera show that when butt gap is appropriate, that is from 0. 1 to 0. 15 mm, molten metals formed on two workpiece uplift and grow up first, then are fused and form uniform molten pool finally. 展开更多
关键词 arc pressure tantalum sheet micro butt gap tungsten inert gas welding mechanism of forming
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Robustness and precision evaluation of the form error of micro-structured surfaces using real coded genetic algorithm 被引量:1
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作者 周京博 孙涛 《Journal of Beijing Institute of Technology》 EI CAS 2012年第4期479-486,共8页
To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm (RCGA). The meth- od employed the average squar... To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm (RCGA). The meth- od employed the average squared distance as the matching criterion. The point to surface distance was achieved by use of iterative method and the modeling of RCGA for the surface matching was also presented in detail. Parameter selection for RCGA including the crossover rate and population size was discussed. Evaluation results of series simulated surfaces without form error show that this method can achieve the accuracy of root mean square deviation ( Sq ) less than 1 nm and surface pro- file error ( St ) less than 4 nm. Evaluation of the surfaces with different simulated errors illustrates that the proposed method can also robustly obtain the form error with nano-meter precision. The e- valuation of actual measured surfaces further indicates that the proposed method is capable of pre- cisely evaluating micro-structured surfaces. 展开更多
关键词 micro-structured surfaces form error evaluation surface matching real coded geneticalgorithm
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Layer-block tectonics of Cenozoic basements and formation of intra-plate basins in Nansha micro-plate, southern South China Sea 被引量:3
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作者 LIU Hailing XIE Guofa +2 位作者 LIN Qiujin ZHENG Hongbo LIU Yingchun 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2009年第3期26-39,共14页
Layer-block tectonics (LBT) concept, with the core of pluralistic geodynamic outlook and multilayer-sliding tectonic outlook, is one of new keys to study 3-dimensional solid and its 4-dimensional evolution history o... Layer-block tectonics (LBT) concept, with the core of pluralistic geodynamic outlook and multilayer-sliding tectonic outlook, is one of new keys to study 3-dimensional solid and its 4-dimensional evolution history of global tectonic system controlled by global geodynamics system. The LBT concept is applied to study the lithospheric tectonics of the southern South China Sea (SCS). Based on the analysis of about 30 000 km of geophysical and geological data, some layer-blocks in the Nansha micro-plate can be divided as Nansha ultra-crustal layer-block, Zengmu crustal layer-block, Nanwei (Rifleman bank)-Andu (Ardasier bank) and Liyue (Reed bank) North Palawan crustal layer-blocks, Andu-Bisheng and Liyue-Banyue basemental layer-blocks. The basic characteristics of the basemental layer-blocks have been dicussed, and three intra-plate basin groups are identified. The intra-plate basins within Nansha micro-plate can be divided into three basin groups of Nanwei- Andu, Feixin-Nanhua, and Liyue-North Palawan based on the different geodynamics. In the light of pluralistic geodynamic concept, the upheaving force induced by the mid-crust plastic layer is proposed as the main dynamical force which causes the formation of the intra-plate basins within the Nansha micro-plate. Finally, models of a face-to-face dip-slip detachment of basemental layerblock and a unilateral dip-slip-detachment of basemental layer-block are put forward for the forming mechanisms of the Nanwei Andu and Liyue-North Palawan intra-plate basin groups, respectively. 展开更多
关键词 layer-block tectonics forming mechanism of intra-plate basin Nansha micro-plate South China Sea oil and gas gas hydrate
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Superplastic Forming and Diffusion Bonding for Sandwich Structure of Ti-6Al-4V Alloy
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作者 Wenbo HAN, Kaifeng ZHANG, Guofeng WANG and Xiaojun ZHANGSchool of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaProf., Ph.D., 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第1期60-62,共3页
Superplastic forming and diffusion bonding (SPF/DB) is a well-established process for the manufacture of components almost exclusively from Ti-6AI-4V sheet material. The sandwich structure of Ti-6AI-4V alloy is invest... Superplastic forming and diffusion bonding (SPF/DB) is a well-established process for the manufacture of components almost exclusively from Ti-6AI-4V sheet material. The sandwich structure of Ti-6AI-4V alloy is investigated. The effects of the microstructure on the SPF/DB process were discussed. The microstructure at the interfaces and the distribution of thickness were researched. 展开更多
关键词 Superplastic forming Diffusion bonding Sandwich structure TI-6A1-4V alloy
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The Evolutionary History of Ore-forming Processes of Metallic Ore Deposits in Northern Guangxi
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作者 Chen Yuchuan, Mao Jinwen and Wang Ping’an Chinese Academy of Geological Sciences, Beijing Fei Zhenbi 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1995年第2期155-170,共16页
The northern Guangxi region is an important rare metal, rare earth metal and polymetallic metallogenic province. In the region there exist five metallogenic series and two metallogenic subseries, whose metallogenesis ... The northern Guangxi region is an important rare metal, rare earth metal and polymetallic metallogenic province. In the region there exist five metallogenic series and two metallogenic subseries, whose metallogenesis shows features of polycyclic spiral evolution throughout the geological history. As far as various cycles are concerned, mantle-derived ore substances were reduced while crust-derived ore substances increased from early to late timesfin the whole geological evolutionary history, mantle-derived substances decreased gradually while crust-derived ones increased. Meanwhile ore element associations became more and more varied. In terms of space, mineralization migrated from the old basement outwards, i.e. from west to east during the Precambrian, and from north to south during the Phanerozoic, and again from east to west during the Yanshanian. 展开更多
关键词 metallogenic series evolutionary history of ore - forming processes metallogenic model rare metal- nonferrous metal deposit
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The Protective Effects of Flavonoids from Scutellaria Baicalensis Georgi Stems and Leaves on Oligodendrocyte Damage Induced by Aβ1-42
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作者 Tangtang Song Yinhui Yao Yazhen Shang 《Pharmacology & Pharmacy》 2024年第1期1-13,共13页
Aim: This study aimed to investigate the protective effects of flavonoids from the stem and leaves of Scutellaria baicalensis Georgi (SSFs) against Aβ<sub>1-42</sub>-induced oligodendrocytes (OL) damage. ... Aim: This study aimed to investigate the protective effects of flavonoids from the stem and leaves of Scutellaria baicalensis Georgi (SSFs) against Aβ<sub>1-42</sub>-induced oligodendrocytes (OL) damage. Methods: Immunofluorescence was used for the detection of myelin-associated glycoprotein (MAG), a characteristic protein of rat oligodendrocytes (OLN-93 cells). To evaluate the potential protective effects of SSFs on OLN-93 cells injured by Aβ<sub>1-42</sub>, an injury model was established by subjecting OLN-93 cells to Aβ<sub>1-42</sub> exposed. Cell morphology was examined using an inverted microscope, while cell viability was assessed using the colorimetric method of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Additionally, lactate dehydrogenase (LDH) was measured using the pyruvic acid reduction assay. The Ginkgo biloba leaf extract (GBE) injection was used as a positive control. Results: A total of >95% of the MAG immunofluorescence-positive cells were identified as oligodendrocytes. Gradually increasing concentrations of SSFs impaired the cells, and the maximum nondetrimental dose for OLN-93 cells was 75 mg/L. This study assessed the effects of SSFs on OLN-93 cells damaged by Aβ<sub>1-42</sub>. The results indicated that SSFs significantly improved OLN-93 cell morphological abnormal changes, increased the OLN-93 cell survival rate, and reduced LDH release. Conclusion: SSFs can alleviate Aβ<sub>1-42</sub>-induced damage of OL. 展开更多
关键词 Flavonoids form the Stem and Leaves of Scutellaria baicalensis Georgi 1-42 OLIGODENDROCYTES DAMAGE
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The Forming Conditions of and Ore-searching Direction for B, Mg,Pb, Zn and Au Deposits in the Liaoji Proterozoic Rift
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作者 Zhu Yongzheng and Yao Fengliang (College of Earth Sciences,Jilin University, Changchun 130026 P. R. China) 《Global Geology》 2001年第1期20-25,共6页
The Liaoji Proterozoic rift is an inter-intracontinenatl rift developed from Archean granite-greenstone tectonic regime and contains many important mineral deposits of U, B, magnesite, Pb-Zn, Au, Ag, Co and P. These d... The Liaoji Proterozoic rift is an inter-intracontinenatl rift developed from Archean granite-greenstone tectonic regime and contains many important mineral deposits of U, B, magnesite, Pb-Zn, Au, Ag, Co and P. These deposits were formed as the result of late mobilization, transportation and concentfation of the previously enriched ore-forming mate- rials in several ore-bearing formations formed during the rift stage. So the metallogeny of these deposits in the rift shows both inheritance and new generation of the ore-forming materials. In future ore-searching practice, attentions should be paid on the studies of the ore-bearing formations in the rift, on the multiple stages of metallogeny and and on multiple derivations of the ore-forming materials. 展开更多
关键词 Liaoji PROTEROZOIC rift B Mg Pb - Zn AU deposits ORE - forming conditions ORE - SEARCHING direction
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5-羟色胺转运蛋白显像剂^(11)C-DASB的自动化合成及Micro PET/CT显像
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作者 张晓军 刘健 +2 位作者 李云钢 田嘉禾 张锦明 《同位素》 CAS 2015年第1期1-6,共6页
目的:自动化合成5-羟色胺转运蛋白显像剂11 C-DASB并进行大鼠Micro PET/CT显像;方法:通过改变甲基化试剂、溶解前体溶剂及反应条件,得到优化的标记条件作为碳-11多功能合成模块的输入参数,进行自动化合成11 C-DASB,大鼠静脉注射11 C-DAS... 目的:自动化合成5-羟色胺转运蛋白显像剂11 C-DASB并进行大鼠Micro PET/CT显像;方法:通过改变甲基化试剂、溶解前体溶剂及反应条件,得到优化的标记条件作为碳-11多功能合成模块的输入参数,进行自动化合成11 C-DASB,大鼠静脉注射11 C-DASB 45 min后进行显像;结果:采用11 C-CH3-Triflate作为甲基化试剂,通入新配制的含1mg去甲基DASB前体的500μL DMSO溶液内,80℃下加热2min,标准率为63.7%,大鼠显像表明,11 C-DASB特异性的浓聚于SERT富集区域;结论:经优化,11 C-DASB自动化合成可得到较高产率,大鼠显像表明,其特异性浓聚于SERT富集区域,有望作为5-羟色胺转运蛋白显像剂。 展开更多
关键词 ^11C-DASB 5-羟色胺转运蛋白 micro PET/CT
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^(18)F-氟赤硝基咪唑micro PET/CT评价裸鼠乳腺癌早期放疗疗效实验研究 被引量:3
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作者 苏晓雨 徐慧琴 +3 位作者 汪会 余文静 张丹 谯凤 《安徽医科大学学报》 CAS 北大核心 2019年第2期203-206,共4页
目的探讨^(18)F-氟赤硝基咪唑micro PET/CT评价裸鼠MDA-MB231乳腺癌早期放疗疗效的价值。方法建立16只裸鼠MDA-MB231乳腺癌模型,将其按照随机对照原则分为两组:对照组(A组)、放疗组(B组),每组8只。每组裸鼠行micro PET/CT显像,测定每只... 目的探讨^(18)F-氟赤硝基咪唑micro PET/CT评价裸鼠MDA-MB231乳腺癌早期放疗疗效的价值。方法建立16只裸鼠MDA-MB231乳腺癌模型,将其按照随机对照原则分为两组:对照组(A组)、放疗组(B组),每组8只。每组裸鼠行micro PET/CT显像,测定每只裸鼠肿瘤SUVmax值。完成显像后,常规HE染色观察每组肿瘤组织形态学特征,免疫组化方法测定每组肿瘤细胞乏氧诱导因子-1α(HIF-1α)的表达情况。结果放疗前,对照组与放疗组SUVmax值差异无统计学意义(t=0. 375,P> 0. 05)。放疗组放疗后48 h裸鼠肿瘤组织SUVmax值较放疗前(t=9. 958,P <0. 05)、放疗后24 h(t=16. 506,P <0. 05)明显降低,差异有统计学意义(F=58. 860,P <0. 05)。放疗后24 h SUVmax值也低于放疗前24 h(t=5. 405,P <0. 05),差异有统计学意义。HE染色结果显示放疗组肿瘤细胞坏死较对照组更加明显。免疫组化结果显示放疗组放疗后HIF-1α表达阳性率明显低于放疗前(t=14. 802,P <0. 05),差异具有统计学意义。相关性分析结果显示肿瘤SUVmax与HIF-1α的表达呈明显正相关性(r=0. 865,P <0. 05)。结论^(18)F-氟赤硝基咪唑micro PET/CT可以监测肿瘤内部的乏氧状态,并且可以评价裸鼠MDA-MB231乳腺癌的早期放疗疗效。 展开更多
关键词 18F-氟赤硝基咪唑 micro PET/CT 放疗疗效 乏氧诱导因子-
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