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Determination of the Thermal Expansion Coefficient of Concrete at Early Ages by Using Temperature-stress Testing Machine
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作者 霍凯成 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第4期146-149,共4页
By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved : temperature rising due to hydration heat is... By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved : temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice. 展开更多
关键词 CONCRETE coefficient of thermal expansion temperature-stress test
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Determination Method of Thermal Expansion Coefficient of Cordierite
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作者 YANG Daoyuan ZHU Kai WU Juan 《China's Refractories》 CAS 2013年第4期14-17,共4页
Cordierite ceramics were prepared by using talc, bauxite and kaolin clay as starting materials. According to the detected resuh of XRD step-scanning from 25° to 35° by a high temperature X-ray diffractometer... Cordierite ceramics were prepared by using talc, bauxite and kaolin clay as starting materials. According to the detected resuh of XRD step-scanning from 25° to 35° by a high temperature X-ray diffractometer, 20 and d values of five peaks of cordierite crystal were ascer- rained. Then the least squares technique was used to cal- culate the crystal parameters : at 25 ℃ , a = b = O. 981 8 nm, c =0. 927 4 nm, V=O. 774 3 nm3 ; at 600 ℃ , a =b =O. 982 0 nm, c=0.9252 nm, V=O. 773 5 nm3. The crystal volumetric coefficient of thermal expansion (CTE) and linear CTE along a and c axes were calcu- lated, αv = 2. 33 × 10-6℃-1, αa = αb, = 3. 27 × 10-6℃ -1 , αc = -4.19 ×10-6℃ -1. The average CTE of cordierite crystal is as low as O. 78 × 10-6℃ -1 展开更多
关键词 CORDIERITE thermal expansion coefficient calculation method high temperature XRD
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Effect of Heat Treatment Temperature on Properties of Chinese Calcined Flint Clay Based Plastic Refractories 被引量:23
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作者 ZHANG Wei DAI Wenyong YU Xinfeng LI Liang 《China's Refractories》 CAS 2009年第2期27-29,共3页
Effects of different heat treatment temperatures on properties of Chinese calcined flint clay based plastic refractories were investigated using Chinese calcined flint clay as starting material, aluminum sulfate and f... Effects of different heat treatment temperatures on properties of Chinese calcined flint clay based plastic refractories were investigated using Chinese calcined flint clay as starting material, aluminum sulfate and fireclay as binding system. The results showed that with temperature rising, Chinese calcined flint clay based plastic refractories shrinked firstly and then expanded. The modulus of rupture (MOR) and the cold crushing strength (CCS) inereased firstly and then decreased from 110 ℃ to 600 ℃ , then increased obviously. Thermal expansion coefficient increased from 110 ℃ to 760 ℃, decreased from 760 ℃ to 1 300 ℃ , and increased from 1 300 ℃ to1500 ℃. 展开更多
关键词 Chinese calcined flint clay based plastic refractories Fireclay Heat treatment temperature Thermal expansion coefficient
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Influence of Chemical Composition on Phase Transformation Temperature and Thermal Expansion Coefficient of Hot Work Die Steel 被引量:8
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作者 XIE Hao-jie WU Xiao-chun MIN Yong-an 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2008年第6期56-61,共6页
On the basis of the uniform design method, six kinds of martensitic hot work die steels were designed. The phase transformation temperatures including Ac1 , Ac3 , and Ms were measured by DIL805A quenching dilatometer.... On the basis of the uniform design method, six kinds of martensitic hot work die steels were designed. The phase transformation temperatures including Ac1 , Ac3 , and Ms were measured by DIL805A quenching dilatometer. The influences of the main elements on phase transformation temperatures were analyzed by quadratic stepwise regression analysis, and three corresponding equations were obtained. These equations, in which the interactions of the elements were considered, showed more effectiveness than the traditional ones. In addition, the thermal expansion coefficients of these steels in annealed state and quenched state were also obtained during the tests. The influences of chemical composition and temperature on the thermal expansion coefficient were analyzed; the equations obtained were verified by using several kinds of steels. The predicted values were in accordance with the results of the experiments. 展开更多
关键词 phase transformation temperature thermal expansion coefficient hot work die steel uniform design quadratic stepwise regression analysis
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Effects of Chemical Treatments on Thermal Expansion Properties of Cordierite Ceramics 被引量:3
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作者 白佳海 郭露村 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第3期100-102,共3页
Cordierite honeycomb ceramics was treated with 1.5 M HNO3 , followed with 1.5 M NaOH at 93 ℃. The combination of acid treatment with alkali treatment significantly diminished the rebounding of coefficient of thermal ... Cordierite honeycomb ceramics was treated with 1.5 M HNO3 , followed with 1.5 M NaOH at 93 ℃. The combination of acid treatment with alkali treatment significantly diminished the rebounding of coefficient of thermal expansion (CTE) caused by heat treatment, a phenomenon observed in samples treated solely with acid. Inductively coupled plasma (ICP) analysis results reveal that the alkali treatment preferentially dissolved "free" SiO2 left in the acid-treated samples, which is considered to be a key factor responsible for the CTE rebounding. 展开更多
关键词 CORDIERITE alkali treatment coefficient of thermal expansion (cte
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Effect of Beryllium Aluminum Cyclosilicate on Thermal Expansion Behavior of Al-Based Composites 被引量:1
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作者 V. Bharat B. Durga Prasad K. Venkateswarlu 《Journal of Minerals and Materials Characterization and Engineering》 2017年第3期140-152,共13页
Beryllium aluminum cyclosilicate, an ore of beryllium was reinforced in Aluminum matrix to fabricate Al-beryl composites using powder metallurgy. Effect of the content of beryllium aluminum cyclosilicate on microstruc... Beryllium aluminum cyclosilicate, an ore of beryllium was reinforced in Aluminum matrix to fabricate Al-beryl composites using powder metallurgy. Effect of the content of beryllium aluminum cyclosilicate on microstructural hardness and thermal expansion was studied. The coefficient of thermal expansion of Al-beryl composite was measured in the temperature range between 50oC to 360oC using dilatometer and was theoretically studied using thermo-elastic models, and these models were used to explain abnormalities observed experimentally. The hardness of Al-beryl metal matrix composites increased with the increase in beryl percentage. Vacuum sintering of Al-beryl metal matrix composites at 600oC inhibited excellent bonding between the matrix and the particulate increasing the strength of the composite. The result shows the CTE significantly increased with increasing temperature but decreased with increasing reinforcement. At higher temperatures, CTE of Al-beryl metal matrix composites with 5 wt%, 10 wt% and 15 wt% of beryllium aluminum cyclosilicate was 21 ppm/K, 18.2 ppm/K, and 16.8 ppm/K. The CTE values were found to be comparable with theoretical results. The turner model showed conformance with experimental results, was well suited to the experimental results. 展开更多
关键词 Al-Beryl MMCS Powder METALLURGY HARDNESS coefficient of Thermal expansion (cte) Thermo-Elastic Models
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Influence of average radii of RE3+ ions on phase structures and thermal expansion coefficients of high-entropy pyrosilicates 被引量:1
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作者 Zeyu Chen Chucheng Lin +4 位作者 Wei Zheng Xuemei Song Caifen Jiang Yaran Niu Yi Zeng 《Journal of Advanced Ceramics》 SCIE EI CAS CSCD 2023年第5期1090-1104,共15页
High-entropy pyrosilicate element selection is relatively blind, and the thermal expansion coefficient (CTE) of traditional β-type pyrosilicate is not adjustable, making it difficult to meet the requirements of vario... High-entropy pyrosilicate element selection is relatively blind, and the thermal expansion coefficient (CTE) of traditional β-type pyrosilicate is not adjustable, making it difficult to meet the requirements of various types of ceramic matrix composites (CMCs). The following study aimed to develop a universal rule for high-entropy pyrosilicate element selection and to achieve directional control of the thermal expansion coefficient of high-entropy pyrosilicate. The current study investigates a high-entropy design method for obtaining pyrosilicates with stable β-phase and γ-phase by introducing various rare-earth (RE) cations. The solid-phase method was used to create 12 different types of high-entropy pyrosilicates with 4–6 components. The high-entropy pyrosilicates gradually transformed from β-phase to γ-phase with an increase in the average radius of RE^(3+) ions ( r¯(RE^(3+))). The nine pyrosilicates with a small r¯(RE^(3+)) preserve β-phase or γ-phase stability at room temperature to the maximum of 1400 ℃. The intrinsic relationship between the thermal expansion coefficient, phase structure, and RE–O bond length has also been found. This study provides the theoretical background for designing high-entropy pyrosilicates from the perspective of r¯(RE^(3+)). The theoretical guidance makes it easier to synthesize high-entropy pyrosilicates with stable β-phase or γ-phase for the use in environmental barrier coatings (EBCs). The thermal expansion coefficient of γ-type high-entropy pyrosilicate can be altered through component design to match various types of CMCs. 展开更多
关键词 environmental barrier coatings(EBCs) high-entropy pyrosilicates phase structure thermal expansion coefficient(cte)
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Thermal Expansion of Solids
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作者 Zdzislaw Pluta Tadeusz Hryniewicz 《Journal of Modern Physics》 2012年第8期793-802,共10页
The work covers a novel approach to the description of the phenomenon of thermal expansion of solids. The reason for undertaking the scientific quest is presented to follow with the analysis of existing knowledge on t... The work covers a novel approach to the description of the phenomenon of thermal expansion of solids. The reason for undertaking the scientific quest is presented to follow with the analysis of existing knowledge on the characteristics of phenomenon of thermal expansion of bodies being in the state of aggregation. A critical approach to the existing law of the linear thermal expansion is given. The paper presents an adequate approach to this considered phenomenon. The description provides parametric and functional characteristics of this phenomenon. The relationships of the coefficients of linear expansion on temperature for particular interstate zones, as well as the initial coefficients related to these zones, are presented. In the summary a synthesis of all actions and considerations with the directions to the adequate knowledge with advantage on the subjected phenomenon has been performed. It regards also to the latest thermal characteristics of solids, referred to the phase transformations. All they are realized by dilatometric studies together with determination of curves of thermal expansions of solids. 展开更多
关键词 Thermal expansion coefficient of Linear Thermal expansion Relative Length Increment temperature Constant temperature Potential Field Deformation Potential Field Nominal Potential Field Deformation-temperature Space
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基于温度--应力试验的混凝土温度应力仿真
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作者 赵志方 王哲 +3 位作者 朱敏敏 赵志刚 施韬 刘艳明 《浙江工业大学学报》 CAS 北大核心 2024年第5期487-491,共5页
为分析早龄期混凝土的温度变形和温度应力,使用ABAQUS有限元分析软件,考虑混凝土的热膨胀系数和弹性模量随等效龄期的变化规律,通过现有的堆石坝面板混凝土温度—应力试验测试数据建立温度—应力试验试件有限元分析模型,开展混凝土温度... 为分析早龄期混凝土的温度变形和温度应力,使用ABAQUS有限元分析软件,考虑混凝土的热膨胀系数和弹性模量随等效龄期的变化规律,通过现有的堆石坝面板混凝土温度—应力试验测试数据建立温度—应力试验试件有限元分析模型,开展混凝土温度变形对应的温度场和应力场的数值仿真研究。研究结果表明:使用等效龄期,考虑早龄期混凝土热膨胀系数、弹性模量的时变性,可以提高温度应力场仿真模拟的精度,为实际工程提供更安全的设计依据。 展开更多
关键词 温度—应力试验 等效龄期 热膨胀系数 仿真计算
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Sm_(2)Y_(1-x)Al_(x)TaO_(7)陶瓷材料的热物理性能
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作者 刘保福 朱金矿 《中国陶瓷》 CAS CSCD 北大核心 2024年第4期17-22,共6页
以高纯度Al_(2)O_(3)、Y_(2)O_(3)、Sm_(2)O_(3)和Ta_(2)O_(5)为原材料,采用高温烧结方法制备了Sm_(2)Y_(1-x)Al_(x)TaO_(7)系列陶瓷材料,对其晶体结构、显微组织、元素组成、热导率和热膨胀性能进行了系统研究。结果表明,除Sm_(2)Y_(0.... 以高纯度Al_(2)O_(3)、Y_(2)O_(3)、Sm_(2)O_(3)和Ta_(2)O_(5)为原材料,采用高温烧结方法制备了Sm_(2)Y_(1-x)Al_(x)TaO_(7)系列陶瓷材料,对其晶体结构、显微组织、元素组成、热导率和热膨胀性能进行了系统研究。结果表明,除Sm_(2)Y_(0.5)Al_(0.5)TaO_(7)具有焦绿石结构之外,其余三种氧化物均具有单一的萤石晶体结构。其块体材料相对致密度均在90%以上,晶界清晰,各元素摩尔比与其化学式基本一致。由于Al^(3+)和Y^(3+)之间较大的离子半径和原子量差别,增大了对声子的散射,其热传导性能随着Al_(2)O_(3)含量的增加而降低。虽然Al_(2)O_(3)含量增加降低了其热膨胀系数,其大小与YSZ基本相当,所制备陶瓷在室温至1400℃范围内具有良好的相稳定性能。 展开更多
关键词 高温热防护涂层 稀土钽氧化物 热导率 热膨胀系数
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温度变化对CPⅢ平面测量结果的影响
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作者 李杰 《测绘标准化》 2024年第3期58-64,共7页
目前我国高速铁路建设里程已达3万余公里,在全球首屈一指。在高铁建设过程中,轨道控制网(CPⅢ)测量是一项必不可少的工作。某高铁CPⅢ建网测量过程中,相同点位搭接时两次测量结果坐标较差较大,不满足规范搭接要求,需进行外业补测。本文... 目前我国高速铁路建设里程已达3万余公里,在全球首屈一指。在高铁建设过程中,轨道控制网(CPⅢ)测量是一项必不可少的工作。某高铁CPⅢ建网测量过程中,相同点位搭接时两次测量结果坐标较差较大,不满足规范搭接要求,需进行外业补测。本文对搭接不成功处的数据进行了分析,认为两次测量温差较大可能是导致搭接不成功的原因之一,温度变化会对CPⅢ测量结果产生影响。同时,梁体宽度确定时引入混凝土膨胀系数计算得到的梁体宽度变化值与实测值互差较小,均未超过0.7 mm,验证了本文的观点。根据气温变化调整补测时间后,数据成果满足规范要求。最后通过定量分析得出,若将梁体宽度变化阈值设置为±2 mm,梁体宽度为9.25 m时,两次测量温差不应超过-21.6℃~21.6℃;梁体宽度为12.20 m时,两次测量温差不应超过-16.4℃~16.4℃。 展开更多
关键词 CPⅢ测量 温差 混凝土膨胀系数 梁体宽度
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负性光敏聚酰亚胺的种类及研究进展
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作者 孙孟冉 罗雄科 +3 位作者 陶克文 王义明 王杰 郭旭虹 《华东理工大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第1期15-29,共15页
由于优异的综合性能,负性光敏聚酰亚胺已成为微电子领域不可或缺的材料,根据负性光敏聚酰亚胺结构和合成工艺的不同,总结了其主要种类和研究进展。随着微电子技术的高度集成化和扇出型晶圆级封装技术的发展,对负性光敏聚酰亚胺材料提出... 由于优异的综合性能,负性光敏聚酰亚胺已成为微电子领域不可或缺的材料,根据负性光敏聚酰亚胺结构和合成工艺的不同,总结了其主要种类和研究进展。随着微电子技术的高度集成化和扇出型晶圆级封装技术的发展,对负性光敏聚酰亚胺材料提出了更高的要求,如更低的介电常数、更低的热膨胀系数和更低的固化温度等。本文进一步介绍了负性光敏聚酰亚胺材料的不同改性方法及其微观作用机制,并对比分析了各类改性方法的优缺点,为高性能负性光敏聚酰亚胺材料的设计开发提供理论基础。 展开更多
关键词 负性光敏聚酰亚胺 改性 介电常数 热膨胀系数 低温固化
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锆合金表面高温抗氧化涂层的研究进展
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作者 朱林丹 肖华强 +4 位作者 任丽蓉 肖易 莫太骞 林波 田雨鑫 《中国有色金属学报》 EI CAS CSCD 北大核心 2024年第9期2869-2894,共26页
锆合金因其热中子吸收截面小、热膨胀系数低,以及与UO2良好的相容性而成为当前核反应堆中主要的构件材料。然而,在高温蒸汽氧化环境中,锆合金会快速氧化失效,并产生大量氢气,从而引发氢爆炸。为了提高核反应堆的安全性,对锆合金表面进... 锆合金因其热中子吸收截面小、热膨胀系数低,以及与UO2良好的相容性而成为当前核反应堆中主要的构件材料。然而,在高温蒸汽氧化环境中,锆合金会快速氧化失效,并产生大量氢气,从而引发氢爆炸。为了提高核反应堆的安全性,对锆合金表面进行强化形成高温抗氧化防护涂层,是解决这一难题的有效途径。本文介绍了锆合金表面高温氧化行为,重点综述了高温抗氧化涂层(包括金属涂层、陶瓷涂层以及复合涂层)的氧化行为和失效机理,对比分析了不同锆合金表面涂层高温氧化性能。另外,还对锆合金表面高温抗氧化涂层的多元素成分设计、制备方法和梯度结构设计的发展方向进行了展望。 展开更多
关键词 锆合金 蒸汽氧化 高温抗氧化涂层 热膨胀系数
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聚吡咯共轭结构对碳纤维增强树脂基复合材料热循环稳定性能的影响
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作者 姜梦敏 王一璠 +2 位作者 金欣 王闻宇 肖长发 《纺织学报》 EI CAS CSCD 北大核心 2024年第10期23-30,共8页
为解决碳纤维增强树脂基复合材料(CFRPs)存在的碳纤维与基体间界面黏结性较弱和在热循环过程中因热膨胀系数不匹配而产生界面破坏的问题,通过低温聚合得到含有较多共轭结构的聚吡咯(PPy)对预处理后碳纤维(CF)进行表面改性,分别在0、30... 为解决碳纤维增强树脂基复合材料(CFRPs)存在的碳纤维与基体间界面黏结性较弱和在热循环过程中因热膨胀系数不匹配而产生界面破坏的问题,通过低温聚合得到含有较多共轭结构的聚吡咯(PPy)对预处理后碳纤维(CF)进行表面改性,分别在0、30、60℃下制得碳纤维/聚吡咯复合纤维(PPy/CF),并研究了不同聚合温度下制备的CFRPs的界面结合性能、热膨胀性能和热循环稳定性能。结果表明:PPy/CF-0纤维的表面粗糙度与CF相比增加了2.09倍,这有利于树脂锚定在碳纤维表面,从而提高界面结合性能;并且PPy/CF-0纤维表面的聚吡咯层具有较完善的共轭结构,整体表现为负热膨胀系数,使得复合材料的层间剪切强度和界面剪切强度分别达到了CF的1.56倍和1.70倍;此外还使得CFRPs的热循环稳定性有了较明显的提升,经100次热循环实验后,其剪切强度仍能保持在初始数值的70%以上。 展开更多
关键词 碳纤维增强树脂基复合材料 聚吡咯 界面结合性能 负热膨胀系数 热循环稳定性 聚合温度
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高温熔盐储罐基础中陶粒的材料性能试验研究
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作者 易自砚 李红星 +1 位作者 何邵华 赵晴 《太阳能学报》 EI CAS CSCD 北大核心 2024年第7期584-589,共6页
高温熔盐储罐中储热介质温度约600℃,要求每天温降不超过1℃,为满足保温要求,储罐基础常以陶粒作为保温材料。通过对不同级配下5种典型陶粒的化学成分、材料特性和高温热工参数等进行试验研究,得到了陶粒的物理力学性能、相变温度、热... 高温熔盐储罐中储热介质温度约600℃,要求每天温降不超过1℃,为满足保温要求,储罐基础常以陶粒作为保温材料。通过对不同级配下5种典型陶粒的化学成分、材料特性和高温热工参数等进行试验研究,得到了陶粒的物理力学性能、相变温度、热膨胀系数和不同温度(20~600℃)下的导热系数等关键参数,揭示了陶粒的导热特性和变形机理。 展开更多
关键词 太阳能热发电站 热膨胀系数 导热系数 熔盐储罐基础 陶粒 相变温度
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热处理对激光熔覆GX4CrNi13-4显微组织和力学性能的影响
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作者 何凌欢 李家民 +3 位作者 张华炜 侯娟 田馨妮 黄爱军 《核技术》 EI CAS CSCD 北大核心 2024年第6期99-109,共11页
激光熔覆凭借低成本、高效率被激光再制造领域重点关注,激光熔覆制造的GX4CrNi13-4马氏体不锈钢是一种核电站中应用广泛的结构材料。为改善激光熔覆制件低塑性问题,需进行热处理组织结构调控,改善其力学性能。采用激光熔覆技术制备了GX4... 激光熔覆凭借低成本、高效率被激光再制造领域重点关注,激光熔覆制造的GX4CrNi13-4马氏体不锈钢是一种核电站中应用广泛的结构材料。为改善激光熔覆制件低塑性问题,需进行热处理组织结构调控,改善其力学性能。采用激光熔覆技术制备了GX4CrNi13-4不锈钢样品,对其热处理组织开展调控研究。首先通过热膨胀试验推导出该合金的奥氏体相变开始温度为620℃,作为热处理工艺开发的基准参考温度。分别制定了固溶时效(1050℃保温1 h+550℃保温4 h,简称固溶时效处理)和单时效(620℃保温2 h,简称单时效处理)两种热处理工艺,对比研究了热处理对覆层金属显微组织和力学性能的影响作用。然后采用X射线衍射仪、光学显微镜、扫描电子显微镜、透射电子显微镜对热处理后的显微组织结构和物相分布等进行表征,并对热处理前后的样品进行室温拉伸性能测试。结果表明:激光熔覆GX4CrNi13-4马氏体不锈钢沉积态样品基体组织主要为马氏体/铁素体双相组织,铁素体相呈连续网状结构,沿马氏体晶界析出,此外还存在少量残余奥氏体。经固溶时效热处理后,基体仍主要由马氏体和铁素体组成,但连续网状铁素体发生分解,且出现大量微米级马氏体晶内析出物,这导致材料塑性略有提升,但强度显著下降。对覆层样品进行单时效热处理,由于温度处于奥氏体相转变临界温度,样品中产生了逆变奥氏体相,该相在拉伸过程中引发相变诱发塑性(Transformation Induced Plasticity,TRIP)效应。此外,单时效处理后沿马氏体析出的网状铁素体进一步得到分解,呈离散分布。TRIP效应和铁素体分解的共同作用下,有效改善了激光熔覆GX4CrNi13-4不锈钢的塑性同时使得强度被较好地保持。激光熔覆工艺在修复和再制造领域具有广泛的应用前景,但熔覆过程的高冷却速度、复杂的热循环对材料的组织结构产生影响,使得修复件往往具有高强度但塑韧性不足。开展合适的热处理组织性能调控是改善材料综合力学性能的有效手段,在激光熔覆GX4CrNi13-4不锈钢的热处理工艺研究中,选择奥氏体相变温度作为时效温度,利用逆变奥氏体TRIP效应和网状铁素体分解的联合作用,获得强度-塑性匹配的良好力学性能。 展开更多
关键词 马氏体不锈钢 激光熔覆 逆变奥氏体 热处理增韧 热膨胀系数 奥氏体转变温度
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Mixed Alkali-zinc Effects on Thermo-mechanical Properties in Borosilicate Glasses
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作者 XIAO Guanzhou TAO Yunhang +3 位作者 ZHOU Hemin ZHENG Qingshuang QIAO Ang TAO Haizheng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第5期1093-1099,共7页
A series of mixed alkali-zinc borosilicate glasses with various r values(r=molar ratio of[ZnO]/([R^(2)O]+[ZnO]))from 0.00 to 1.00 were fabricated to probe the mixed alkali-zinc effects on thermo-mechanical properties.... A series of mixed alkali-zinc borosilicate glasses with various r values(r=molar ratio of[ZnO]/([R^(2)O]+[ZnO]))from 0.00 to 1.00 were fabricated to probe the mixed alkali-zinc effects on thermo-mechanical properties.The nonlinear evolution of glass transition temperature(T_(g))with the addition of ZnO is ascribed to the competition of two converse factors,i e,the T_(g)depression as one of the colligative properties for a solution,on the one hand,and the enhancement of T_(g)due to the higher field strength of zinc cations compared to that of alkali ions.However,the nonlinear evolution of elastic moduli and coefficients of thermal expansion with r is attributed to the variance of intermediate-range clusters,which is confirmed by infrared and Raman scattering spectra.These findings are very helpful in tailoring the performance of borosilicate glasses. 展开更多
关键词 glass transition temperature elastic moduli coefficient of thermal expansion borosilicate glass
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CuO掺量对ZnO-B_(2)O_(3)-Bi_(2)O_(3)玻璃结构与热性能的影响
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作者 向婉婷 罗欣 +3 位作者 江正迪 连启会 黄佳鑫 吴浪 《非金属矿》 2024年第5期5-9,共5页
为了降低硼酸盐无铅封接玻璃的软化温度,研究了CuO掺量(0~15%,质量分数,下同)对40ZnO-30B_(2)O_(3)-30Bi_(2)O_(3)玻璃结构及热性能的影响。结果表明,在950℃保温2 h的熔制工艺条件下,试验组成范围内均能形成均质玻璃。随着CuO掺量增加,... 为了降低硼酸盐无铅封接玻璃的软化温度,研究了CuO掺量(0~15%,质量分数,下同)对40ZnO-30B_(2)O_(3)-30Bi_(2)O_(3)玻璃结构及热性能的影响。结果表明,在950℃保温2 h的熔制工艺条件下,试验组成范围内均能形成均质玻璃。随着CuO掺量增加,ZnO-B_(2)O_(3)-Bi_(2)O_(3)玻璃中的[BO_(3)]/[BO_(4)]结构单元比例先增大后减小,在CuO掺量为8%时达到最大值,此时[BO_(3)]结构单元含量相对较多。当CuO掺量进一步增加,部分[BO_(3)]逐渐向[BO_(4)]转变。此外,随CuO掺量增加,玻璃化转变温度及析晶温度逐渐降低,在400~850℃范围质量损失速率逐渐减小,但15%高掺量时呈现质量增加的趋势。玻璃的平均线热膨胀系数(25~450℃)随CuO增多无明显变化,保持在7.10×10^(-6)℃^(-1)左右。玻璃的软化温度和半球温度呈先降低后升高的趋势,当CuO掺量为8%时,软化温度和半球温度最低。 展开更多
关键词 ZnO-B_(2)O_(3)-Bi_(2)O_(3) 低熔点玻璃 热膨胀系数 软化温度 CUO
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温度对阀门密封比压的影响分析 被引量:1
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作者 刘纯 胡树文 +2 位作者 钟梦妮 杜兰君 李罗金 《阀门》 2024年第7期884-887,共4页
通过仿真研究了不同温度下阀门阀座密封比压的特性,分析不同热膨胀系数对密封比压的影响。结果表明:随着温度的降低,阀门阀座密封比压会稍微增加。此外,在一定范围内,阀芯材料热膨胀系数的变化对密封比压的影响不大,几乎可以忽略。当阀... 通过仿真研究了不同温度下阀门阀座密封比压的特性,分析不同热膨胀系数对密封比压的影响。结果表明:随着温度的降低,阀门阀座密封比压会稍微增加。此外,在一定范围内,阀芯材料热膨胀系数的变化对密封比压的影响不大,几乎可以忽略。当阀座的热膨胀系数小于1E-5 K^(-1)时,阀座热膨胀系数变化对密封比压的影响不大,随着温度的降低密封比压几乎不变;当阀座材料的热膨胀系数大于1E-5 K^(-1)时,在低温下阀门的密封比压随着阀座热膨胀系数的增大而增大,这为低温阀门选择阀芯和阀座材料提供一定的参考。 展开更多
关键词 阀门 密封比压 温度 热膨胀系数
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基于泰勒展开的混凝土超声测试温度效应研究
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作者 郑罡 彭宇 +1 位作者 陈鹏 薛文琪 《传感器与微系统》 CSCD 北大核心 2024年第8期44-48,共5页
为研究环境温度对混凝土超声尾波信号的影响,在室内自然环境条件下,采集环境温度变化下的混凝土工字梁超声尾波信号。利用泰勒展开,分温度区段进行分析处理超声尾波信号,逐步提取信号中各阶温度效应成分并逐一去除,建立各阶信号投影系... 为研究环境温度对混凝土超声尾波信号的影响,在室内自然环境条件下,采集环境温度变化下的混凝土工字梁超声尾波信号。利用泰勒展开,分温度区段进行分析处理超声尾波信号,逐步提取信号中各阶温度效应成分并逐一去除,建立各阶信号投影系数与温度效应的拟合关系。结果表明:一阶信号投影系数与温度效应拟合直线的拟合优度高于0.98;去除前二阶温度效应成分后,平均去相关系数可降低97%以上。 展开更多
关键词 温度效应 混凝土 泰勒展开 超声尾波 投影系数
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