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壳管式相变蓄热换热器换热特性的模拟研究 被引量:1
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作者 闫全英 郭媛 张静 《暖通空调》 2023年第11期144-149,共6页
设计了一种以石蜡为相变材料的圆柱型壳管式相变蓄热换热器,以三维单元相变储热模型为研究对象进行了换热数值模拟。分析了相变材料的液相比、温度场、平均温度及换热介质出口温度的变化规律,研究了该壳管式相变蓄热换热器在蓄、放热阶... 设计了一种以石蜡为相变材料的圆柱型壳管式相变蓄热换热器,以三维单元相变储热模型为研究对象进行了换热数值模拟。分析了相变材料的液相比、温度场、平均温度及换热介质出口温度的变化规律,研究了该壳管式相变蓄热换热器在蓄、放热阶段的换热特性。结果表明:液相石蜡的自然对流会增强相变材料与换热介质之间的换热,并加快石蜡的熔化和凝固速率;蓄热阶段液相比达到18.6%后,自然对流换热的影响逐渐明显;放热阶段初期,液相比在80 s内下降了63%,固态石蜡层完全包裹传热管束前的自然对流换热最强,之后逐渐减弱。 展开更多
关键词 管式变蓄热换热器 换热特性 石蜡 变材料 蓄热 放热 自然对流换热
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均匀粒度分布的双壳相变储湿微胶囊制备 被引量:2
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作者 张浩 熊磊 +1 位作者 徐紫茹 刘秀玉 《复合材料学报》 EI CAS CSCD 北大核心 2017年第11期2556-2561,共6页
分别以正十八烷、甲基丙烯酸甲酯和壳聚糖作为核材料、内壳和外壳,采用细乳液原位聚合法及界面聚合法制备双壳相变储湿微胶囊。通过均匀设计与径向基函数神经网络结合,考察因素(如乳化剂用量、助乳化剂用量、引发剂用量、超声乳化时间... 分别以正十八烷、甲基丙烯酸甲酯和壳聚糖作为核材料、内壳和外壳,采用细乳液原位聚合法及界面聚合法制备双壳相变储湿微胶囊。通过均匀设计与径向基函数神经网络结合,考察因素(如乳化剂用量、助乳化剂用量、引发剂用量、超声乳化时间和搅拌速度)对双壳相变储湿微胶囊粒度分布的影响,并且对最均匀粒度分布双壳相变储湿微胶囊进行表征与测试。结果表明,当扩展系数为0.55时,径向基函数神经(Radial Basis Function,RBF)网络具有最佳的逼近效果。最均匀粒度分布双壳相变储湿微胶囊的制备工艺参数:乳化剂用量为3.58wt%、助乳化剂用量为0.53wt%、引发剂用量为1.86wt%、超声乳化时间为11.35 min,搅拌速度为632r·min^(-1)。基于上述制备参数,d_(10)为3 352.0nm、d50为4 474.9nm,d_(90)为6 108.4nm,d_(90)-d_(10)实测值为2 756.4nm,实测值与预测值吻合较好,相对误差为2.69%。在相对湿度35%~65%的平衡含湿量为0.0547~0.1259g·g^(-1),相变温度为28.87℃,相变焓为78.45J·g^(-1)。 展开更多
关键词 激光粒度 RBF神经网络 壳相变储湿微胶囊 均匀粒度分布 预测方法
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一种新型核壳型色谱固定相在高效液相色谱中的评价及应用 被引量:6
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作者 孙元社 瞿其曙 +3 位作者 于淑新 李霜霜 唐涛 李彤 《色谱》 CAS CSCD 北大核心 2016年第12期1249-1253,共5页
采用扫描电镜、透射电镜和氮气吸附法对制备的新型核壳型色谱固定相进行了表征,结果表明该固定相单分散性好、表面放射状孔道壳层结构均一、孔径分布窄。对该核壳材料的表面进行C18键合修饰,考察其基本色谱性能,色谱柱的理论塔板数超过1... 采用扫描电镜、透射电镜和氮气吸附法对制备的新型核壳型色谱固定相进行了表征,结果表明该固定相单分散性好、表面放射状孔道壳层结构均一、孔径分布窄。对该核壳材料的表面进行C18键合修饰,考察其基本色谱性能,色谱柱的理论塔板数超过150 000块/m,色谱峰峰形对称,甲苯与乙苯的保留因子之比为1.45,亚甲基选择性优异。将该核壳材料应用于汽车尾气中醛酮类化合物的检测,在优化的色谱条件下,2,4-二硝基苯肼(DNPH)衍生的醛酮类化合物在15 min内获得了较好的分离效果。该核壳型C18色谱固定相具有分离速度快、选择性好、柱效高等特点,适于复杂样品的高效、快速分离分析。 展开更多
关键词 高效液色谱 型色谱固定 评价与应用 醛酮类化合物
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SiO2/松香-腰果酚核壳型液相色谱固定相高效分离天麻素 被引量:6
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作者 李国祥 邓杰 +2 位作者 曾磊 史伯安 雷福厚 《分析化学》 SCIE EI CAS CSCD 北大核心 2019年第12期1946-1950,共5页
以腰果酚、松香、球形硅胶为主要原料,制备了SiO2/松香-腰果酚核壳型高效液相色谱柱,可高效分离天麻素。将腰果酚进行酯化改性,封闭酚羟基,然后以腰果酚酯为单体、改性松香为交联剂、偶氮二异丁腈为引发剂,将三者混合并均匀涂敷到硅胶表... 以腰果酚、松香、球形硅胶为主要原料,制备了SiO2/松香-腰果酚核壳型高效液相色谱柱,可高效分离天麻素。将腰果酚进行酯化改性,封闭酚羟基,然后以腰果酚酯为单体、改性松香为交联剂、偶氮二异丁腈为引发剂,将三者混合并均匀涂敷到硅胶表面,通过自由基聚合反应成功制备了一种核(SiO2)-壳(膜)型液相色谱固定相。采用红外光谱、扫描电镜和透射电镜对固定相进行了表征。采用湿法装柱,并选用苯基-β-D-吡喃葡萄糖苷和对甲氧基苯基-β-D-吡喃葡萄糖苷作为天麻素的竞争分子,以乙腈-0.05%H3PO4(3∶97,V/V)为流动相,检测波长220 nm,流速0.3 mL/min,初步研究了固定相在室温下对天麻素的分离性能。此固定相的粒径约为5μm,且粒径分布均一,壳(膜)厚约75 nm,对天麻素具有良好的拆分性能,对2种竞争分子的分离度(Rs)分别为7.43和12.35。本方法简单高效,为天麻素的分离纯化提供了新思路。 展开更多
关键词 腰果酚 松香 型固定 天麻素 色谱
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水平壳管式相变蓄能单元传热机理研究
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作者 金玉龙 盛峰 +5 位作者 盛璐腾 王硕 冯乐军 刘志颖 李辉 安雪晖 《暖通空调》 2021年第11期99-104,94,共7页
以水平壳管式相变蓄能单元为研究对象,建立了考虑相变的流动传热耦合数学模型,对蓄能单元熔化/凝固过程的传热机理进行了研究。结果表明:熔化过程传热机理为从以导热主导到以自然对流主导再恢复到以导热主导;而凝固过程,传热机理为全程... 以水平壳管式相变蓄能单元为研究对象,建立了考虑相变的流动传热耦合数学模型,对蓄能单元熔化/凝固过程的传热机理进行了研究。结果表明:熔化过程传热机理为从以导热主导到以自然对流主导再恢复到以导热主导;而凝固过程,传热机理为全程以导热主导;自然对流对熔化过程影响较大,可以强化传热,减少总的熔化时间,而对凝固过程影响很小;由于自然对流的强化传热效果,熔化过程蓄热速率会在快速下降后经历一个先上升再缓慢下降直至熔化结束的过程;凝固过程释热速率呈现快速下降后再缓慢下降直至凝固结束;熔化和凝固过程热量的吸收与释放均以潜热为主。 展开更多
关键词 水平管式变蓄能单元 自然对流 传热机理 熔化/凝固过程 强化传热
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空间双层相贯焊接球壳在冰铜储运仓的应用
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作者 罗晓斌 黄建兵 《有色冶金设计与研究》 2012年第2期33-36,共4页
球面型冰铜储运仓具有单位面积储量大、自动化程度高、便于降低冰铜含水率、对环境污染小、景观好等特点。空间双层相贯焊接的球面网壳结构能充分满足冰铜储运仓的工艺要求,适应仓内储料湿度大、挥发水汽呈弱腐蚀的环境。从建筑设计、... 球面型冰铜储运仓具有单位面积储量大、自动化程度高、便于降低冰铜含水率、对环境污染小、景观好等特点。空间双层相贯焊接的球面网壳结构能充分满足冰铜储运仓的工艺要求,适应仓内储料湿度大、挥发水汽呈弱腐蚀的环境。从建筑设计、结构设计等角度入手,介绍了某冶炼厂项目中空间双层相贯焊接的球面网壳结构在冰铜储运仓的应用,探讨了支座设计和施工安装的要点。 展开更多
关键词 球面型冰铜储运仓 空间双层贯焊接的球面网 固定铰支座
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超高效液相色谱产生的理论和技术背景 被引量:7
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作者 姚碧霞 翁文 《福建分析测试》 CAS 2011年第2期15-20,共6页
阐述了超高效液相色谱产生的理论和技术背景,指出液相色谱速率理论、色谱保留理论等的研究,色谱仪器的整体优化、新型色谱填料(球形亚二微米填料、整体化材料、核壳型填料、色谱饼等)的开发大大推进了色谱科学的发展,共同推进了超高效... 阐述了超高效液相色谱产生的理论和技术背景,指出液相色谱速率理论、色谱保留理论等的研究,色谱仪器的整体优化、新型色谱填料(球形亚二微米填料、整体化材料、核壳型填料、色谱饼等)的开发大大推进了色谱科学的发展,共同推进了超高效液相色谱的产生。新型色谱填料的研发仍将是今后研究的重点,分析在科学人才培养方面则应注意理论研究与技术创新相结合。 展开更多
关键词 色谱速率理论 色谱保留理论 超高效液色谱 整体柱 型固定 色谱饼
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相接球形压力容器无模爆炸成形技术
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作者 佟铮 何风曼 +1 位作者 王宁 马万珍 《压力容器》 2000年第6期46-48,共3页
Conjugated spherical metal shells are an idea combination of pressure vessels,and the total vessel volume could be adjusted through different combinations of the components.But the difficulties of manufacturing those ... Conjugated spherical metal shells are an idea combination of pressure vessels,and the total vessel volume could be adjusted through different combinations of the components.But the difficulties of manufacturing those conjugated parts limited its wide application of such vessels.The results of non-die explosive forming of conjugated spherical pressure vessels might provide a new and simple manufacturing method of such construction. 展开更多
关键词 接球 无模爆炸成形 压力容器
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Optical Properties of GaAs/AlGaAs Nanowires Grown on Pre-etched Si Substrates
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作者 ZHANG Zhihong MENG Bingheng +2 位作者 WANG Shuangpeng KANG Yubin WEI Zhipeng 《发光学报》 EI CAS CSCD 北大核心 2024年第10期1639-1646,共8页
GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nan... GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nanowires(NWs)is hindered by type-Ⅱquantum well structures arising from the mixture of zinc blende(ZB)and wurtzite(WZ)phases and surface defects due to the large surface-to-volume ratio.Achieving GaAs-based NWs with high emission efficiency has become a key research focus.In this study,pre-etched silicon substrates were combined with GaAs/AlGaAs core-shell heterostructure to achieve GaAs-based NWs with good perpendicularity,excellent crystal structures,and high emission efficiency by leveraging the shadowing effect and surface passivation.The primary evidence for this includes the prominent free-exciton emission in the variable-temperature spectra and the low thermal activation energy indicated by the variable-power spectra.The findings of this study suggest that the growth method described herein can be employed to enhance the crystal structure and optical properties of otherⅢ-Ⅴlow-dimensional materials,potentially paving the way for future NW devices. 展开更多
关键词 GaAs nanowires GaAs/AlGaAs core-shell structure crystal phase optical property
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核壳型二氧化硅色谱填料的研究进展 被引量:13
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作者 夏红军 刘家玮 白泉 《色谱》 CAS CSCD 北大核心 2020年第4期372-382,共11页
复杂样品的高效快速分离分析是分离科学家所面临的挑战。近年来,核壳型二氧化硅色谱填料以其高效、快速和低背压的特点被广泛用于小分子、大分子和复杂样品的快速分离分析。该文系统综述了二氧化硅核壳色谱固定相快速分离的机理,制备方... 复杂样品的高效快速分离分析是分离科学家所面临的挑战。近年来,核壳型二氧化硅色谱填料以其高效、快速和低背压的特点被广泛用于小分子、大分子和复杂样品的快速分离分析。该文系统综述了二氧化硅核壳色谱固定相快速分离的机理,制备方法及其在小分子、多肽和生物大分子快速分离分析方面的应用,同时对核壳型色谱固定相的发展进行了展望。 展开更多
关键词 型色谱固定 高效液色谱 快速分离分析 综述
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聚乙二醇–二氧化硅十八烷酸相变壳核结构胶囊的制备 被引量:11
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作者 蹇守卫 马保国 +2 位作者 金磊 穆松 张琴 《硅酸盐学报》 EI CAS CSCD 北大核心 2010年第4期711-717,共7页
为解决十八烷酸在固–液相变过程中的体积变化问题,针对十八烷酸的结构特点,以十八烷酸、水玻璃和聚乙二醇(polyethylene glycol,PEG)为原料制备了PEG–SiO2复合壳和SiO2单层壳2种十八烷酸微胶囊,采用参比温度、差热分析、热重分析、X... 为解决十八烷酸在固–液相变过程中的体积变化问题,针对十八烷酸的结构特点,以十八烷酸、水玻璃和聚乙二醇(polyethylene glycol,PEG)为原料制备了PEG–SiO2复合壳和SiO2单层壳2种十八烷酸微胶囊,采用参比温度、差热分析、热重分析、X射线衍射、Fourier变换红外光谱,扫描电子显微镜和X射线能谱分析仪分别对2种微胶囊的热性能、形貌和结构进行了比较。结果表明:热循环50次后,PEG–SiO2复合壳结构的相变热稳定性比SiO2单层壳结构微胶囊的更好;PEG–SiO2复合壳和SiO2单层壳十八烷酸微胶囊的相变焓分别为78.40J/g和88.61J/g,PEG–SiO2复合壳微胶囊中PEG与十八烷酸接枝导致十八烷酸的相变焓降低,并出现结晶缺陷;PEG–SiO2复合壳为PEG与SiO2相互交错结构。 展开更多
关键词 变储能 微胶囊 聚乙二醇–二氧化硅 十八烷酸
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γ-Ray-Radiation-Scissioned Chitosan as a Gene Carrier and Its Improved in vitro Gene Transfection Performance 被引量:1
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作者 林福星 曾琨 +5 位作者 杨文秀 汪谟贞 荣洁琳 谢娟 赵宇 葛学武 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第2期231-238,I0002,共9页
Chitosan (CS) is expected to be an ideal gene carrier for its high biosafety. In this work, CS with low molecular weight were prepared through the γ-ray radiation on the acetic acid solution of CS. The CS chains we... Chitosan (CS) is expected to be an ideal gene carrier for its high biosafety. In this work, CS with low molecular weight were prepared through the γ-ray radiation on the acetic acid solution of CS. The CS chains were scissioned under the γ-ray radiation, and the molecu- lar weight (MW) of CS decreased with the absorbed dose. When the absorbed dose was above 30 kGy, the molecular weight of CS decreased about an order of magnitude. The γ-ray-radiation-scissioned CS can effectively bind with plasmid (pEGFP) through complex coacervation method, forming pEGFP/γ-ray-radiation-scissioned CS complex particles with a size of 200-300 nm. The complex particles have good stability and little cytotoxicity. The in vitro gene transfection efficiencies of the pEGFP/γ-ray-radiation-scissioned CS complex particles were investigated by fluorescence microscope and flow cytometry. The results showed that the gene vectors using γ-ray-radiation-scissioned CS as the carrier will possess better gene transfection efficiency than those using natural high-MW CS as the carrier. The higher the absorbed dose, the smaller the MW of CS and the better transfection efficiency of the corresponding gene vector. This work provides a green and simple method on the preparation of CS-based gene vectors with high efficiency and biosafety. 展开更多
关键词 CHITOSAN BIOCOMPATIBILITY Radiation scission Gene transfection
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车辆乘务舱半物理环境模拟下的调温调湿材料性能分析
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作者 张雪武 方从严 +1 位作者 潘骏 张浩 《化工新型材料》 CAS CSCD 北大核心 2016年第9期228-230,共3页
车辆乘务舱半物理环境模拟系统,以环境测试舱作为车辆乘务舱的模拟环境,研究石膏基双壳微米相变胶囊复合材料的调温性能和调湿性能。结果表明,石膏基双壳微米相变胶囊复合材料具有显著的吸放湿效果和吸放热效果,其性能随双壳微米相变胶... 车辆乘务舱半物理环境模拟系统,以环境测试舱作为车辆乘务舱的模拟环境,研究石膏基双壳微米相变胶囊复合材料的调温性能和调湿性能。结果表明,石膏基双壳微米相变胶囊复合材料具有显著的吸放湿效果和吸放热效果,其性能随双壳微米相变胶囊掺入量的增加而增强。研究可为调温调湿材料在车辆乘务舱中的实际应用提供一定的理论依据和指导。 展开更多
关键词 车辆乘务舱 模拟环境 微米变胶囊 调温调湿
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梅兰芳冰上踩高跷
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作者 范靖国 《冰雪运动》 1984年第4期64-,共1页
我国著名京剧表演艺术家梅兰芳,台步轻捷,武工娴熟,开打亮相都很轻松漂亮.他的精湛技艺,是经过不断刻苦锻炼才得来的.其中冰上踩高跷,就是他独特的锻炼方法之一.为练就扎实的腰腿功,梅兰芳少年时冬天在自家庭院里找块地方浇成冰场,然后... 我国著名京剧表演艺术家梅兰芳,台步轻捷,武工娴熟,开打亮相都很轻松漂亮.他的精湛技艺,是经过不断刻苦锻炼才得来的.其中冰上踩高跷,就是他独特的锻炼方法之一.为练就扎实的腰腿功,梅兰芳少年时冬天在自家庭院里找块地方浇成冰场,然后腿脚上捆上高跷,到冰上去跑圆场.冰面光洁如镜,人走上去也难免摔跤,更何况高跷重心高、支撑面小呢?因此,梅兰芳在冰上踩高跷时,经常摔倒,身上摔得青一块。 展开更多
关键词 京剧表演艺术 腰腿功 跷功 支撑面 红线女 伎艺 梅先生 穆柯寨 壳相 于冰
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Genetic study on seed coat characteristics in multiploid watermelon 被引量:1
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作者 陈娟 《Agricultural Science & Technology》 CAS 2007年第2期13-20,共8页
[ Objective] This study is to provide basis for the genetic improvement of triploid watermelon cultivars from seed coat characteristiscs by analyzing its genetic properties. [ Method ] Genetic effects of seed coat cha... [ Objective] This study is to provide basis for the genetic improvement of triploid watermelon cultivars from seed coat characteristiscs by analyzing its genetic properties. [ Method ] Genetic effects of seed coat characteristics and their related characteristics in tdploid watermelon were analyzed by additive dominant genetic model based on 36 F1 hybrids which were crossed by six female parents of four ecotypes and six male parents of same ecotype according to North Carolina II crossing design. [ Result] The seed coat number characteristics was controlled by additive effects, dominant effects and error variance of genetic together. The additive effects of the length and width of abortive seed coat were significant, and the error variance was significant or highly significant. It was observed that there was a significant negative correlation of additive effects between the seed coat number and fringe soluble sugar. Also there was a significant negative correlation of dominant effects between lycopenes, dry matter and the seed coat number. However, there was a highly significant positive correlation in additive effects between the length and width of abortive seed coat. [ Conclusion ] The results provide guidance for genetic breeding of triploid watermelon cultivars. 展开更多
关键词 triploid watermelon seed coat characteristics genetic effect correlation analysis
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Effects of chitosan coating on biocompatibility of Mg-6%Zn-10%Ca_3(PO_4)_2 implant 被引量:1
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作者 赵俊 陈良建 +5 位作者 余琨 陈畅 戴翌龙 乔雪岩 颜阳 余志明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期824-831,共8页
A Mg?6%Zn?10%Ca3(PO4)2 composite with a chitosan coating was prepared to study its in vivo biodegradation properties. The chitosan dissolved in a 0.2% acetic acid solution was applied on the surface of Mg?6%Zn?10%Ca3(... A Mg?6%Zn?10%Ca3(PO4)2 composite with a chitosan coating was prepared to study its in vivo biodegradation properties. The chitosan dissolved in a 0.2% acetic acid solution was applied on the surface of Mg?6%Zn?10%Ca3(PO4)2 composite specimens and solidified at 60 °C for 30 min to form the coating. The cytotoxicity evaluation of chitosan coated specimens is at level 0, which indicates that such coating is safe for cellular applications. The in vivotests of chitosan coated composite show that the concentration of metal ions from the composite measured in the venous blood of Zelanian rabbits is less than that from the uncoated composite specimens. The chitosan coating impedes the in vivo degradation of the composite after surgery. The in vivo testing also indicates that the chitosan coated composite is harmless to important visceral organs, including the heart, kidneys and liver of the rabbits. The new bone formation surrounding the chitosan coated composite implant shows that the composite improves the concrescence of the bone tissues. And the chitosan coating is an effective corrosion resistant layer that reduces the hydrogen release of the implant composite, thereby decreasing the subcutaneous gas bubbles formed. 展开更多
关键词 BIOCOMPATIBILITY magnesium composite CHITOSAN CYTOTOXICITY
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广州车展引领汽车科技大变革
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《汽车与配件》 2014年第49期14-15,共2页
随着消费者对于汽车的认知水平越来越高,直接关乎车型性能表现的技术也越来越被汽车厂家所重视。广州车展上市、预售、亮相的各款新车中,搭载核心创新技术的车型更容易让消费者感受到汽车品牌新的诚意。直喷增压与混合动力本质不同如果... 随着消费者对于汽车的认知水平越来越高,直接关乎车型性能表现的技术也越来越被汽车厂家所重视。广州车展上市、预售、亮相的各款新车中,搭载核心创新技术的车型更容易让消费者感受到汽车品牌新的诚意。直喷增压与混合动力本质不同如果单从市场普及率来看,现阶段显然是直喷增压占据上风。不仅大众全面普及直喷增压。 展开更多
关键词 广州车展 汽车科技 消费者感受 直喷 增压发动机 加速力 效仿者 壳相 桂木 效率差异
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斯柯达速派的前世今生
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《汽车与驾驶维修(汽车版)》 2015年第10期38-39,共2页
当我们想全面了解一款车或者一个品牌时,它的历史内涵必然是不可忽视的因素之一。正如酒是越老越醇一样,斯柯达也是个有着百年悠久历史的经典品牌,而它旗下的旗舰车型——速派(Superb)也不觉间走过了八十多年的历史。
关键词 斯柯达 经典品牌 旗舰车 大众汽车集团 中级轿车 历史内涵 法兰克福车展 新旗舰 外观设计 壳相
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Coherence of wind pressure on domes 被引量:3
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作者 尼尼昂 叶继红 《Journal of Southeast University(English Edition)》 EI CAS 2010年第1期100-106,共7页
The concept of the coherence function is adopted to find the wind pressure correlation of two points on domes of different rise-span ratios. The pressure measurements are made on the dome roof models by the wind tunne... The concept of the coherence function is adopted to find the wind pressure correlation of two points on domes of different rise-span ratios. The pressure measurements are made on the dome roof models by the wind tunnel test. The coherence functions for different separation distances at several directions of the domes from different wind directions are examined. The results show that there is a strong correlation for two adjacent points at low frequency, but not for non-adjacent points. The coherence of the wind pressure increases with the decrease in the separation distance. Moreover, the coherence of the wind pressure is in the strongest correlation on the along-wind direction at the same separation, but the lowest correlation is on the cross-wind direction. The detailed derivation of the proposed exponential coherence model of the wind pressure from experimental data is also discussed. It is found that the proposed exponential coherence model can be appropriate, especially, for small separations and the change in the directions on domes. Based on the quasi-steady theory, the relationship between the wind pressure and the wind velocity on the basis of the coherence model is also examined. The coherence observed between the wind pressure and the wind velocity is not adequately predicted by the quasi-steady theory. 展开更多
关键词 DOMES coherence of wind pressure exponential coherence model of wind pressure quasi-steady theory
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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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