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圆锥壳-圆柱壳-球壳组合结构自由振动分析 被引量:9
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作者 吴仕昊 瞿叶高 华宏星 《振动与冲击》 EI CSCD 北大核心 2013年第6期109-114,120,共7页
基于Reissner薄壳理论,采用区域分解法分析了不同边界条件下圆锥壳-圆柱壳-球壳组合结构的自由振动。首先在壳体连接处将组合壳体分为独立的圆锥壳、圆柱壳和球壳,并将各个子壳体沿旋转轴线分解为若干自由壳段;然后将所有壳段分区界面(... 基于Reissner薄壳理论,采用区域分解法分析了不同边界条件下圆锥壳-圆柱壳-球壳组合结构的自由振动。首先在壳体连接处将组合壳体分为独立的圆锥壳、圆柱壳和球壳,并将各个子壳体沿旋转轴线分解为若干自由壳段;然后将所有壳段分区界面(包括边界界面)的位移协调方程通过分区广义变分和最小二乘加权残值法引入到组合壳体的能量泛函中;最后将壳段位移场变量的周向分量和轴向分量分别以Fourier级数和Chebyshev多项式展开,通过变分后得到整个组合壳体的离散动力学方程。将区域分解法计算结果与有限元软件ANSYS计算结果进行对比,验证了区域分解法在分析圆锥壳-圆柱壳-球壳组合结构自由振动的正确性和计算精度,并分析了组合壳体长径比及厚径比对自由振动频率的影响。 展开更多
关键词 区域分解法 分区广义变分 最小二乘加权残值 圆锥-圆柱-组合结构 自由振动
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正交加筋圆柱壳-球壳组合结构自由振动分析 被引量:7
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作者 李正良 胡浩 于伟 《振动与冲击》 EI CSCD 北大核心 2015年第22期129-137,共9页
研究不同边界条件下光滑、正交加筋圆柱壳-球壳组合结构的自由振动。通过对圆柱壳与球壳连接处简化处理,视球壳为自由约束,圆柱壳为简支约束,据Flügge薄壳理论利用Rayleigh-Ritz法求得结构频率,与有限元软件ANSYS结果比较,验证该... 研究不同边界条件下光滑、正交加筋圆柱壳-球壳组合结构的自由振动。通过对圆柱壳与球壳连接处简化处理,视球壳为自由约束,圆柱壳为简支约束,据Flügge薄壳理论利用Rayleigh-Ritz法求得结构频率,与有限元软件ANSYS结果比较,验证该方法的适用性及有效性;分析球壳扁率及组合壳体长径比对频率影响。结果表明,球心半角Φ增大结构自振频率降低;长径比L/Rc增大球心半角Φ对组合结构频率影响逐渐减弱,结构自振频率逐渐降低,且降幅减小。 展开更多
关键词 加筋圆柱-组合结构 Flügge理论 Rayleigh-Ritz法 自由振动
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核-壳结构硅灰石/磷酸钙多孔陶瓷微球的制备及表征 被引量:3
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作者 柳丽敏 张雷 +4 位作者 杨贤燕 壮琛 柯秀荣 杨国敬 苟中入 《材料科学与工程学报》 CAS CSCD 北大核心 2017年第1期19-25,共7页
本文研究了双壳层型核-壳结构β-硅灰石/β-磷酸三钙(β-CaSiO3/β-TCP)生物活性复相陶瓷微球的制备及表征;利用添加有机微球造孔剂工艺,在内、外壳层分别构建出孔径10μm左右的多孔结构,并对其体外降解行为进行了分析。结果显示,运用... 本文研究了双壳层型核-壳结构β-硅灰石/β-磷酸三钙(β-CaSiO3/β-TCP)生物活性复相陶瓷微球的制备及表征;利用添加有机微球造孔剂工艺,在内、外壳层分别构建出孔径10μm左右的多孔结构,并对其体外降解行为进行了分析。结果显示,运用自制同轴喷头微流控系统制备的生物活性复相陶瓷微球的工艺简单,微球尺寸均一,球形形态良好,经干燥、煅烧处理后陶瓷微球发生明显收缩,颗粒度维持在2.2±0.1mm。通过改变组分分布、烧结温度制度以及双壳层内部结构等实现复相陶瓷体外降解的可调节性。以上研究结果表明,该方法制备的多孔双壳层型核-壳结构复相陶瓷微球解决了组分降解速率调控问题,以及由此堆砌颗粒形成三维网络孔道演化可调可控性能,势必将在研究骨缺损修复和微球载药领域具有重要意义。 展开更多
关键词 Β-磷酸三钙 β-硅酸钙 层核-结构 多孔结构 复相陶瓷微球
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Fabrication of Cu_2O@Cu_2O core-shell nanoparticles and conversion to Cu_2O@Cu core-shell nanoparticles in solution 被引量:2
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作者 杨爱玲 李顺嫔 +3 位作者 王玉金 王乐乐 包西昌 杨仁强 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第11期3643-3650,共8页
Cu2O@Cu2O core-shell nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Cu2O@Cu2O NPs were easily converted to Cu2O@Cu NPs with the help of polyvinylpyrrolidine (PVP) and excessive a... Cu2O@Cu2O core-shell nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Cu2O@Cu2O NPs were easily converted to Cu2O@Cu NPs with the help of polyvinylpyrrolidine (PVP) and excessive ascorbic acid (AA) in air at room temperature, which was an interesting phenomenon. The features of the two kinds of NPs were characterized by XRD, TEM and extinction spectra. Cu2O@Cu NPs with different shell thicknesses showed wide tunable optical properties for the localized surface plasmon (LSP) in metallic Cu. But Cu2O@Cu2O NPs did not indicate this feature. FTIR results reveal that Cu+ ions on the surface of Cu2O shell coordinate with N and O atoms in PVP and are further reduced to metallic Cu by excessive AA and then form a nucleation site on the surface of Cu2O nanocrystalline. PVP binds onto different sites to proceed with the reduction utill all the Cu sources in Cu2O shell are completely assumed. 展开更多
关键词 Cu2O@Cu2O core-shell nanoparticles Cu2O@Cu core-shell nanoparticles solution phase strategy reducing agent tunable optical properties polyvinylpyrrolidine
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Reinforcement by polyurethane to stiffness of air-supported fabric formwork for concrete shell construction 被引量:2
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作者 GUO Xiao QIAN Sheng-shen +1 位作者 QING Qiang GONG Jing-hai 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第9期2569-2577,共9页
By spraying concrete on inner surface,air-supported fabric structures can be used as formwork to construct reinforced concrete shell structures.The fabric formwork has the finished form of concrete structure.Large dev... By spraying concrete on inner surface,air-supported fabric structures can be used as formwork to construct reinforced concrete shell structures.The fabric formwork has the finished form of concrete structure.Large deviation from the desired shape of concrete shells still remains as central problem due to dead weight of concrete and less stiffness of fabric formwork.Polyurethane can be used not only as a bonding layer between fabrics and concrete but also as an additional stiffening layer.However,there is little research on mechanical behaviors of the polyurethane shell structure.This paper presents experimental studies on an inflated fabric model with and without polyurethane,including relief pressure tests,vertical loading tests and horizontal loading tests.Experimental results show that the additional polyurethane layer can significantly enhance the stiffness of the fabric formwork.Compared with the experiment,a numerical model using shell layered finite elements has a good prediction.The reinforcement by polyurethane to improve stiffness of air-supported fabric formwork is expected to be considered in the design and construction of the concrete shell,especially dealing with the advance of shape-control. 展开更多
关键词 fabric formwork POLYURETHANE STIFFNESS thin-shell structure loading experiment shell layered finite element
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Analysis and experiment of a vessels shell cover in submarine structure 被引量:1
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作者 ZHANGYu-li ZENGGuang-wu 《Journal of Marine Science and Application》 2004年第1期14-19,共6页
This paper aims to achieve analysis and experiment resuhs that relate to mechanics capability and structural parameter of a special saddle shell of revolution. Theoretically speaking, the saddle shell of revolution co... This paper aims to achieve analysis and experiment resuhs that relate to mechanics capability and structural parameter of a special saddle shell of revolution. Theoretically speaking, the saddle shell of revolution consists of a toroidal shell and a spherical shell. The shells simultaneous equations can be solved with harmonious terms. Where, the fundamental equations can be solved by as-ymptotic exponential perturbation method. The equations of special solution can be solved by Hovozhilovs special solution. This new idea is from a study of some existing solutions of the toroidal shell. The resuhs have been proved by compared with some experimental results. The experiments aims to study the effect caused by change of material parameter, or by change of different geometric dimensions of the saddle shell, which include the change of thickness, the change of radius of shell, and the change of ribs. Finally, the accepted product of the saddle shell were reinforced by a toroidal rib has been submitted. 展开更多
关键词 SADDLE toroidal shell spherical shell EXPERIMENT RIB perturbation method
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Numerical and Experimental Investigation of an Elliptical Paraboloid Shell Model
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作者 Hamadi Djamal Mellas Mekki Chebili Rachid 《Computer Technology and Application》 2011年第4期324-328,共5页
For practical engineering purpose, a new flat shell element baptized (ACM_Q4SBE1) is presented in this paper. The formulated element can be used for the analysis of thin shell structures; no matter how the geometric... For practical engineering purpose, a new flat shell element baptized (ACM_Q4SBE1) is presented in this paper. The formulated element can be used for the analysis of thin shell structures; no matter how the geometrical shape might be. Tests on standard problems have been examined. Since, the analysis of thin shell structures has generally been purely carried out on a theoretical basis; it is of importance to present some experimental results of an elliptical paraboloid under uniformly distributed load pressure. The results obtained from both numerical and experimental work are presented. 展开更多
关键词 Elliptical paraboloid finite element flat shell element.
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Buckling Load Evaluation Method for Single Layer Cylindrical Lattice Shells
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作者 Seishi Yamada 《Journal of Civil Engineering and Architecture》 2012年第3期268-279,共12页
A rational design evaluation procedure is investigated for the elastic overall buckling load carrying capacity of single layer cylindrical lattice shell roof structures. The nature of the imperfection sensitivity of t... A rational design evaluation procedure is investigated for the elastic overall buckling load carrying capacity of single layer cylindrical lattice shell roof structures. The nature of the imperfection sensitivity of these structures is for the first time reviewed in this paper. This allows the development of the reduced stiffness buckling analytical concept for the lattice shells based upon the introduction of a simple lower bound estimation equation through the use of the so-called continuum shell analogy theory. The linear and nonlinear buckling loads found from conventional finite element analyses are compared with the present estimations. Finally, the elastic-plastic load carrying capacity estimation method through the use of the present elastic lower bound criteria is also proposed. 展开更多
关键词 Metal lattice shell BUCKLING design formula cylindrical barrel vault roof structure.
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Ni@RuM(M=Ni or Co) core@shell nanocrystals with high mass activity for overall water-splitting catalysis 被引量:5
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作者 Shan Zhang Fan Lv +7 位作者 Xiaoyan Zhang Yelong Zhang Haishuang Zhu Huanhuan Xing Zijie Mu Jing Li Shaojun Guo Erkang Wang 《Science China Materials》 SCIE EI CSCD 2019年第12期1868-1876,共9页
Developing efficient water-splitting electrocatalysts with high mass activity is in urgent need for largescale sustainable production of hydrogen but,still remains as a big challenge.Herein,we report a one-pot method ... Developing efficient water-splitting electrocatalysts with high mass activity is in urgent need for largescale sustainable production of hydrogen but,still remains as a big challenge.Herein,we report a one-pot method to fabricate a series of core@shell Ni@RuM(M=Ni or Co)nanocrystals(NCs)with Ni as the core and tunable RuM(M=Ni or Co)as the alloy shell for efficient water-splitting catalysis.Among these core@shell NCs,the obtained Ni@Ru Ni NCs exhibit the highest intrinsic activity for hydrogen evolution reaction(HER)and possess an outstanding mass activity of 1590 m A mgRu^-1 at 0.07 V vs.reversible hydrogen electrode(RHE),which is 1.7 times higher than that of commercial Pt/C(950 m A mgPt^-1).As for oxygen evolution reaction(OER),the prepared Ni@Ru0.4 Co0.6 NCs with optimized shell composition achieve more enhanced mass activity of 270 m A mgRu^-1 at1.56 V vs.RHE,approaching three times higher than that of commercial RuO2(89 m A mgRu^-1).The superb mass activity of these Ni@Ru M(M=Ni or Co)NCs can be attributed to their core@shell structure and modulated electronic structure through alloying with Ni or Co metal in the shell. 展开更多
关键词 ELECTROCATALYSIS RUTHENIUM CORE-SHELL oxygen evolutionreaction hydrogen evolution reaction
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荧光磁性Fe_3O_4@Gd_2O_3∶Eu^(3+)空心球的制备与表征 被引量:1
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作者 付文明 李旺 王军 《中国激光》 EI CAS CSCD 北大核心 2016年第1期154-160,共7页
通过尿素均匀沉淀法合成了荧光磁性Fe_3O_4@Gd_2O_3∶Eu^(3+)纳米空心球,并且设计了一种壳-壳结构。利用模板法合成的这种壳-壳结构很好地避免了磁性纳米粒子的凝聚。扫描电子显微镜(SEM)和透射电子显微镜(TEM)测试结果表明,得到的Fe_3O... 通过尿素均匀沉淀法合成了荧光磁性Fe_3O_4@Gd_2O_3∶Eu^(3+)纳米空心球,并且设计了一种壳-壳结构。利用模板法合成的这种壳-壳结构很好地避免了磁性纳米粒子的凝聚。扫描电子显微镜(SEM)和透射电子显微镜(TEM)测试结果表明,得到的Fe_3O_4@Gd_2O_3∶Eu^(3+)空心球直径均约为390 nm,并且磁性层和荧光层的厚度分别约55 nm和15 nm。壳的厚度和空心纳米球的尺寸可以很容易地通过调整原料的浓度和氧化硅模板的尺寸来控制。所制备的Fe_3O_4@Gd_2O_3∶Eu^(3+)空心球表现出较高的饱和磁化强度(17.1 emu/g),在紫外线的激发下发出较强的红光。这种特征使它完全可以应用于靶向治疗、免疫检测、磁性分离、荧光追踪等方面。该合成路线对其他多功能纳米空心球的可控合成也具有重要的意义。 展开更多
关键词 材料 荧光性 磁性 均相沉淀 壳-壳结构
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Hydrocarbon accumulation mechanism and structure of largescale volcanic weathering crust of the Carboniferous in northern Xinjiang,China 被引量:10
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作者 ZOU CaiNeng HOU LianHua +6 位作者 TAO ShiZhen YUAN XuanJun ZHU RuKai JIA JinHua ZHANG XiangXiang LI FuHeng PANG ZhengLian 《Science China Earth Sciences》 SCIE EI CAS 2012年第2期221-235,共15页
The Upper Carboniferous in northern Xinjiang, China was formed in a post-collisional depression and collapsed structural setting. Within the Upper Carboniferous, volcanic rocks and source rocks alternate over a wide r... The Upper Carboniferous in northern Xinjiang, China was formed in a post-collisional depression and collapsed structural setting. Within the Upper Carboniferous, volcanic rocks and source rocks alternate over a wide region. At the end of the Carboniferous, these layers were uplifted by plate collisions and subsequently weathered and leached. Volcanic weathering and leaching led to the establishment of weathered crusts that can be divided into five layers. Corrosion and crumble zones in these layers form favorable reservoirs. Volcanic weathering crust formed in sub-aerially exposed paleogeomorphic areas; the five relatively continuous layers are generally preserved in paleogeomorphic lowland and slope regions, but the upper soil layer is usually absent in structurally higher parts of the rock record. The thickness of the weathered layer has a positive nonlinear ex- ponential relationship to the duration of weathering and leaching, and the dynamic equilibrium time of weathered crust is about 36.3 Ma. The thickest weathered layer (~450 m) is located in fracture zones. Weathered crusts are possible from a range of volcanic rocks with different lithologies, given sufficient time for weathering and leaching. The combination of volcanic weathered crust and source rocks results in three types of hydrocarbon accumulation models: (1) sequences of volcanic weathered crust interbedded with source rocks, (2) a quasi-layered weathered volcanic core located above source rocks, and (3) volcanic rocks associated with pectinate unconformities adjacent to source rocks. Each of these three types has the potential to form a giant stratigraphic reservoir of volcanic weathered crust. This knowledge has changed the traditional exploration model of searching for favorable lithologic and lithofacies zones in volcanic rocks, and has changed the viewpoint that the Carboniferous does not have the genetic potential to be the basement of the basin in northern Xinjiang. The concepts developed here are of great scientific significance and application for focusing oil and gas exploration on volcanic weathered crust. As such, the Paleozoic volcanic weathered crust in the midwestern part of China may possibly contain large-scale stratigraphic reservoirs and thus could be a new oil and gas exploration target in the future. 展开更多
关键词 Carboniferous in northern Xinjiang volcanic weathering crust stratigraphic reservoir accumulation mechanism and model
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A possible mechanism for the formation of annual growth lines in bivalve shells 被引量:1
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作者 LIU XiaoJun YAN ZhenGuang +4 位作者 ZHENG GuiLan ZHANG GuiYou WANG HongZhong XIE LiPing ZHANG RongQing 《Science China(Life Sciences)》 SCIE CAS 2011年第2期175-180,共6页
We report a unique shell margin that differed from the usual shell structure of Pinctada fucata.We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin.Al... We report a unique shell margin that differed from the usual shell structure of Pinctada fucata.We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin.All the characteristics of the growing margin indicated that the shell was growing rapidly.To explain this anomaly,we propose the concept of "jumping development".During jumping development,the center of growth in the bivalve shell jumps forward over a short time interval when the position of the mantle changes.Jumping development explains the unusual structure of the anomalous shell and the development of annual growth lines in typical shells.Annual growth lines are the result of a discontinuity in the shell microstructure induced by jumping development. 展开更多
关键词 bivalves shell microstructure internal growth bands the prismatic layer the nacreous layer
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