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工艺参数对玻纤增强硅树脂复合材料模压成型制品热稳定性与力学性能的影响 被引量:4
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作者 刘学东 薛松 +3 位作者 杨涛 任怡 彭奕 郑丽璇 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2022年第4期94-102,共9页
随着核电的发展,其极端的环境对绝缘部件提出了更高的要求。玻璃纤维增强硅树脂由于优异的物理化学性能,被广泛应用于高温高电压的工况下。为了提高硅树脂的固化度并确保制品性能与材料特性相匹配,以压水堆(PWR)核电机组中控制棒驱动机... 随着核电的发展,其极端的环境对绝缘部件提出了更高的要求。玻璃纤维增强硅树脂由于优异的物理化学性能,被广泛应用于高温高电压的工况下。为了提高硅树脂的固化度并确保制品性能与材料特性相匹配,以压水堆(PWR)核电机组中控制棒驱动机构(CRDM)的磁轭线圈骨架作为玻纤增强硅树脂的模压成型制品,通过热重分析法和差示扫描量热法研究了硅树脂模塑料的固化热行为,优化了制品的模压工艺参数,采用热重分析和拉伸测试表征了制品的热稳定性和力学性能,研究了后固化参数对制品性能的影响。结果表明,与常温相比,175℃后固化24 h的制品拉伸强度增幅最大,提高了122%,热失重质量分数最小,减少了82.25%。硅树脂的失重固化和热氧化降解是影响制品性能的原因。磁轭线圈骨架模压成型工艺参数为模具温度130℃、成型压力50 MPa、保压时间10 min、固化温度175℃、烘烤时间24 h。成型制品通过了核电机组的热老化性能测试验证。 展开更多
关键词 玻纤增强硅树脂复合材料 模压成型 工艺参数 热稳定性 力学性能 固化
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Performance Analysis of Compound Parabolic Concentration Photothermal and Photoelectricity Device for Soil Heating in Facility Agriculture 被引量:2
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作者 Zehui Chang Yanan Peng +2 位作者 xuedong liu Jing Hou Shuaijun Guo 《Transactions of Tianjin University》 EI CAS 2022年第2期144-152,共9页
It is difficult for solanum crops to grow continuously during winter in severe cold regions. Thus, a soil heating system for facility agriculture based on solar concentration technology was proposed, and a novel compo... It is difficult for solanum crops to grow continuously during winter in severe cold regions. Thus, a soil heating system for facility agriculture based on solar concentration technology was proposed, and a novel compound parabolic concentration photothermal and photoelectricity device(CTPV) equipped in the system was designed to address this problem. In accordance with the structure of the device, LightTools optical software was selected to analyze the variation trend of the light escape rate of the device with the diff erent incident angles. On the basis of the calculation results, an experimental test system was used to investigate the relationship of the air temperature of the inlet and the outlet, total output power of the solar cells, and photothermal and photoelectricity efficiency of the device with the operation time during a sunny day. Research results reveal that the light escape rate of the device is 5.36% at an incidence angle of 12°. At a velocity of 1.5 m/s, the maximum air temperature of the outlet can reach 55.6 ℃, and the total output power of the solar cells is 474.4 W. The variation of the total power of the solar cells is consistent with the simulation results. The maximum instantaneous heat collection and the maximum photothermal and photoelectricity efficiency of the device are 306 W and 60.4%, respectively, and the average efficiency is 44.9%. This study can serve as a reference for compound parabolic concentration technology applied for soil heating in facility agricultural soil heating systems. 展开更多
关键词 Facility agriculture Photothermal and photoelectricity CONCENTRATION Soil HEATING
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Microstructure and Mechanical Property of Nanocrystalline NiZr_2 Intermetallic Compound
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作者 xuedong liu Fuhe YUAN Ke LU and Wenduo WEI (National Lab. for RSA, Institute of Metal Research, Chinese Acedemy of Sciences, Shenyang 110015, China)(To whom correspondence should be addressed)( Present address: National Lab. of Corrosion Science and Prot 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1996年第6期409-412,共4页
Single-phase NiZr2 intermetallic compound nanocrystalline samples were synthesized by fully crystallizing the parent amorphous NiZr2 alloy at the temperature interval of 653~1073 K for a certain period of time. High r... Single-phase NiZr2 intermetallic compound nanocrystalline samples were synthesized by fully crystallizing the parent amorphous NiZr2 alloy at the temperature interval of 653~1073 K for a certain period of time. High resolution electron microscope (HREM) observations on the nanophase NiZr2 reveal a Iamellar nano-tWin structure with (110) direction on the nanometer scale, being typically a few interatomic distances to a few nanometers. Microhardness measurements on the single-phase NiZr2 samples indicate that the hardness of nanotwinned NiZr2 is obviously increased in comparison to the amorphous counterpart. When the average grain size increases from 19.1 to 93.9 nm, the variation of the hardness with the average grain size obeys the normal Hall-Petch relation, whereas as the average grain size is smaller than 19.1 nm. the microhardness data deviate from the above relation. 展开更多
关键词 WANG Microstructure and Mechanical Property of Nanocrystalline NiZr2 Intermetallic Compound
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Chronic eosinophilic pneumonia: A case report and review of the literature
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作者 Yunjie Ge Xiudi Han xuedong liu 《Open Journal of Internal Medicine》 2013年第4期121-125,共5页
Objective: We introduce one case of chronic eosinophilic pneumonia (CEP) and review the literature nearly 10 years in order to improve the understanding of this rare disease. Methods: A case of CEP diagnosed by transb... Objective: We introduce one case of chronic eosinophilic pneumonia (CEP) and review the literature nearly 10 years in order to improve the understanding of this rare disease. Methods: A case of CEP diagnosed by transbronchial lung biopsy with clinical and follow-up data was analyzed and its clinical features, diagnosis and treatment combined with the literature were discussed. Result: CEP is a chronic pulmonary eosinophilic inflammation with unknown etiology, characterized by history of allergic disease, cough, sputum, but often breathlessness and wheezing;eosinophil in peripheral blood and/or sputum and/or bronchoalveolar lavage fluid significantly increased;chest X-ray showed progressively peripheral non-segment distribution of high-density infiltrates, often called “reversed pulmonary edema sign”;Pathology showed eosinophil infiltration in lung interstitial, bronchial submucosal and excessive eosinophil exudation in alveolar. Oral corticosteroids had a good response, but easy to relapse. Conclusions: Eosinophil count of bronchoalveolar lavage or lung biopsy can confirm the diagnosis of CEP timely in suspected patients. Bronchoscope can play an important role in assisting diagnosis and improving symptoms. 展开更多
关键词 CHRONIC EOSINOPHILIC PNEUMONIA CASE REPORT
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Impact of inhaled corticosteroid use on elderly chronic pulmonary disease patients with community acquired pneumonia 被引量:1
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作者 Xiudi Han Hong Wang +22 位作者 Liang Chen Yimin Wang Hui Li Fei Zhou Xiqian Xing Chunxiao Zhang Lijun Suo Jinxiang Wang Guohua Yu Guangqiang Wang Xuexin Yao Hongxia Yu Lei Wang Meng liu Chunxue Xue Bo liu Xiaoli Zhu Yanli Li Ying Xiao Xiaojing Cui Lijuan Li xuedong liu Bin Cao 《Chinese Medical Journal》 SCIE CAS CSCD 2024年第2期241-243,共3页
To the Editor:With an aging global population,the incidences of community-acquired pneumonia(CAP)and chronic obstructive pulmonary disease(COPD)have signicantly increased.[1]Previous studies have conrmed that COPD and... To the Editor:With an aging global population,the incidences of community-acquired pneumonia(CAP)and chronic obstructive pulmonary disease(COPD)have signicantly increased.[1]Previous studies have conrmed that COPD and asthma are independently associated with the prevalence of CAP.The use of inhaled corticosteroid(ICS),the cornerstone of treatment for asthma,COPD with frequent acute exacerbations,and asthma-COPD overlap(ACO)may induce changes in the local lung microbiome and abnormal lung immunity,ultimately,causing a signicantly increased risk of pneumonia.However,in cases of pneumonia,the effect of the use of ICS on CAP mortality remains controversial.While data from one study favored the prior use of ICS,which was associated with a signicantly lower short-term mortality rate,[2]other studies have identied no impact on mortality.To date,data on the impact of the use of ICS on mortality,prehospitalization or during hospitalization,are scarce,particularly in the older population.Therefore,this multicenter,retrospective study explored the association between the use of ICS during hospitalization and short-term mortality in older patients with CAP and those with chronic pulmonary disease(CPD). 展开更多
关键词 PNEUMONIA PATIENTS IMMUNITY
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基于相似原理的超细粉体搅拌功率的实验和DEM数值模拟
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作者 陈荟 刘雪东 +3 位作者 刘文明 郑蔚文 张红红 吕开新 《过程工程学报》 CAS CSCD 北大核心 2023年第11期1506-1517,共12页
采用实验研究和数值模拟相结合的方法,研究机械式粉体搅拌机内超细粉体搅拌过程的搅拌功率、扭矩的变化规律。对平均粒径为10.56μm的轻质碳酸钙粉体进行搅拌实验,研究了机械式粉体搅拌机内的操作参数,包括搅拌转速、桨叶位置、料面高... 采用实验研究和数值模拟相结合的方法,研究机械式粉体搅拌机内超细粉体搅拌过程的搅拌功率、扭矩的变化规律。对平均粒径为10.56μm的轻质碳酸钙粉体进行搅拌实验,研究了机械式粉体搅拌机内的操作参数,包括搅拌转速、桨叶位置、料面高度的变化对超细粉体搅拌功率和扭矩的影响,拟合得出了功率计算的表达式。利用相似原理放大粉体细颗粒,对放大的粗颗粒进行虚拟实验,获得接触参数;对粗颗粒搅拌过程进行DEM数值模拟,将模拟搅拌功率和扭矩的结果与实验结果进行比较。结果表明,机械式粉体搅拌机内超细粉体搅拌功率消耗与搅拌桨转速、桨叶位置、料面高度等参数密切相关。同时,扭矩值与功率值与搅拌桨转速、料面高度呈正相关,与桨叶位置呈负相关。模拟的扭矩值和功率值与实验的扭矩值和功率值比值与颗粒放大因子基本吻合,验证了相似原理应用于研究桨叶位置和料面高度对搅拌功率特性的影响的准确性。 展开更多
关键词 超细粉体 搅拌功率 扭矩 相似原理 数值模拟
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A simple and efficient carbon nanotube-based nanocarriers simultaneously delivers multiple plasmids into diverse mature tissues of monocotyledonous crops
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作者 xuedong liu Wenwen Kong +5 位作者 Nian Xiao Lijuan Huang Yu Zhang Weizhao Chen Beixin Mo Yu Yu 《Science China(Life Sciences)》 SCIE CAS CSCD 2023年第7期1701-1704,共4页
Dear Editor,With the development of high-throughput sequencing technology,a large number of functional genes have been identified.However,the illustration of these gene functions is limited,especially in monocot plant... Dear Editor,With the development of high-throughput sequencing technology,a large number of functional genes have been identified.However,the illustration of these gene functions is limited,especially in monocot plants(Chen et al.,2022).One of the main reasons is that genetic transformation is still a major bottleneck for these plants.Recently,nanoparticles(NPs)-mediated biomolecular delivery methods. 展开更多
关键词 MONO ILLUSTRATION CROPS
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管式固定床反应器柱状颗粒床层流体流动模拟与实验研究 被引量:2
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作者 朱梓瑞 刘雪东 +5 位作者 蒋良雄 顾宇彤 彭涛 殷俊杰 刘梅华 蒋威 《过程工程学报》 CAS CSCD 北大核心 2021年第9期1022-1032,共11页
针对管式固定床反应器内管束数量多、规模大等特点,选取单个管束作为特征结构。对装填不同直径柱状颗粒的管束,采用程序坐标定位的方法,建立柱状颗粒床层的物理模型。采用DEM与CFD联合数值仿真方法,探究反应管内径与柱状颗粒的等比表面... 针对管式固定床反应器内管束数量多、规模大等特点,选取单个管束作为特征结构。对装填不同直径柱状颗粒的管束,采用程序坐标定位的方法,建立柱状颗粒床层的物理模型。采用DEM与CFD联合数值仿真方法,探究反应管内径与柱状颗粒的等比表面积球当量直径之比(管径比Di/dp)对柱状颗粒床层流体流动的影响,并建立单管固定床反应器试验台,采用差压测试方法进行实验研究。结果表明,当Di/dp由5.37增至12.75时,床层空隙率和流体分布均匀性均得到改善,壁面效应的影响由床层中心减弱到管壁。基于数值模拟及实验结果对Di/dp=12.75的柱状颗粒床层进行床层压降Ergun公式常系数修正,CFD模拟计算的结果与拟合公式吻合较好。研究结果能为固定床反应器压降预测提供参考。 展开更多
关键词 固定床反应器 柱状颗粒 流体流动特性 数值模拟 压降
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新型热解炉燃烧室流热固耦合仿真与结构优化 被引量:1
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作者 高华鑫 刘雪东 +4 位作者 张炜 查晓峰 吕圣男 刘佳君 吕开新 《过程工程学报》 CAS CSCD 北大核心 2022年第9期1203-1212,共10页
针对新型热解炉燃烧室结构,采用ANSYS Workbench流热固耦合方法,研究不同结构参数下燃烧室的温度场与变形场,获得了最优的燃烧室结构。结果表明,燃烧室内设挡板的结构性能优于无挡板的结构性能,燃烧室内设挡板的温度场变异系数的变化幅... 针对新型热解炉燃烧室结构,采用ANSYS Workbench流热固耦合方法,研究不同结构参数下燃烧室的温度场与变形场,获得了最优的燃烧室结构。结果表明,燃烧室内设挡板的结构性能优于无挡板的结构性能,燃烧室内设挡板的温度场变异系数的变化幅度比无挡板的变化幅度减小0.06,温度场分布更均匀;燃烧室的最大变形出现在燃烧室与热解室之间的隔板上,有挡板的燃烧室最大变形量较无挡板的燃烧室减少80%,且最大变形量均随着挡板位置距中心的距离或挡板长度增加呈先减小后增大的趋势,而挡板厚度对变形场的影响最小;在挡板位置为150 mm,挡板长度为800 mm,挡板厚度为14 mm时,新型热解炉燃烧室的结构最优。 展开更多
关键词 ANSYS工作台 热解炉 燃烧室 流热固耦合 数值模拟
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柱状颗粒沉降过程的CFD-DEM联合仿真和实验研究 被引量:1
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作者 刘佳君 刘雪东 +3 位作者 吕圣男 高华鑫 邵佳伟 张红红 《过程工程学报》 CAS CSCD 北大核心 2022年第12期1643-1651,共9页
针对柱状催化剂颗粒相对于球形颗粒的不同运动特性,选择不同长度直径为2 mm的5种柱状颗粒,采用CFD-DEM数值模拟仿真,研究柱状颗粒在管状容器中沉降的运动行为,并建立柱状颗粒沉降试验台,采用高速摄像拍摄的方法进行实验研究。结果表明,... 针对柱状催化剂颗粒相对于球形颗粒的不同运动特性,选择不同长度直径为2 mm的5种柱状颗粒,采用CFD-DEM数值模拟仿真,研究柱状颗粒在管状容器中沉降的运动行为,并建立柱状颗粒沉降试验台,采用高速摄像拍摄的方法进行实验研究。结果表明,在不同位置释放相同直径和长度的柱状颗粒时,靠近壁面释放的颗粒会在沉降过程中向中心漂移,且比中心释放的颗粒沉降更慢,时间更长;改变柱状颗粒与水平面的夹角,在圆管中心释放颗粒,最终颗粒都会旋转至水平状态,与水平面夹角越大,底部所受阻力越大,转动持续时间随之增加;推导柱状颗粒沉降斯托克斯方程,并通过实验数据对方程中的阻力系数进行修正,将修正后的阻力系数导入用户自定义函数(UDF)计算颗粒沉降末速度,相对误差从原来使用球形颗粒阻力系数的50%下降到17%以内,模拟较为可靠。 展开更多
关键词 柱状颗粒 沉降 计算流体力学 CFD-DEM联合仿真 高速摄像
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Mixed invasive pulmonary Mucor and Aspergillus infection:a case report and literature review
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作者 Peikun Teng Xiudi Han +4 位作者 Shuli Zhang Dong Wei Yi Wang Deshun liu xuedong liu 《Chinese Medical Journal》 SCIE CAS CSCD 2022年第7期854-856,共3页
To the Editor:Invasive pulmonary mucormycosis(IPM)is a rare but life-threatening opportunistic fungal disease with a high mortality rate of 40%to 80%.[1]Although IPM accounts for approximately 9.2%of all mucormycosis ... To the Editor:Invasive pulmonary mucormycosis(IPM)is a rare but life-threatening opportunistic fungal disease with a high mortality rate of 40%to 80%.[1]Although IPM accounts for approximately 9.2%of all mucormycosis cases,it has the highest mortality rate(66.6%).A definitive diagnosis of IPM depends on the histopathological findings,regardless of culture results of the respiratory tract specimens or lung tissues. 展开更多
关键词 MORTALITY diagnosis LUNG
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