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直接掺杂法制备聚酰亚胺/纳米氧化铝复合层压板 被引量:1
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作者 黄洪驰 饶保林 张先来 《绝缘材料》 CAS 2007年第3期4-6,10,共4页
采用直接掺杂法制备了聚酰亚胺/纳米Al2O3复合层压板。通过弯曲试验、冲击试验、热重分析、线膨胀系数、导热系数等测试方法研究了Al2O3含量、成型条件与层压板性能之间的关系。结果表明,引入纳米Al2O3可以较大幅度提高层压板的高温力... 采用直接掺杂法制备了聚酰亚胺/纳米Al2O3复合层压板。通过弯曲试验、冲击试验、热重分析、线膨胀系数、导热系数等测试方法研究了Al2O3含量、成型条件与层压板性能之间的关系。结果表明,引入纳米Al2O3可以较大幅度提高层压板的高温力学性能和表观分解温度,并在一定程度上提高了层压板的导热系数。Al2O3含量为14.5%时,300℃下的弯曲强度及弯曲模量达到最大值,分别为110 MPa和3.64 GPa,约为纯亚胺板的3倍以上。Al2O3含量为8.9%时,表观分解温度达到最大值(585℃),比纯亚胺板的表观分解温度(567℃)提高了近20℃。成型压力在100-225 kgf/cm^2之间、成型温度为365℃时,层压板可以获得较好的综合性能。 展开更多
关键词 可熔性聚酰亚胺 层压板 纳米氧化铝 纳米复合 直接掺杂
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纳米掺杂和直接掺杂Li2O-SiO2复合助烧剂对X7R型BaTiO3基陶瓷显微结构和介电性能的影响
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作者 米超辉 崔斌 +2 位作者 游桥明 畅柱国 史启祯 《功能材料》 EI CAS CSCD 北大核心 2011年第11期2068-2072,2077,共6页
以Li2O-SiO2(LSO)复合组分作为助烧剂,比较纳米掺杂和直接掺杂对X7R型BaTiO3基陶瓷显微结构和介电性能的影响,并进一步研究直接掺杂LSO的用量及烧结温度的影响,同时通过缺陷化学理论探讨了陶瓷的烧结机制。实验结果表明与纳米掺杂相比,... 以Li2O-SiO2(LSO)复合组分作为助烧剂,比较纳米掺杂和直接掺杂对X7R型BaTiO3基陶瓷显微结构和介电性能的影响,并进一步研究直接掺杂LSO的用量及烧结温度的影响,同时通过缺陷化学理论探讨了陶瓷的烧结机制。实验结果表明与纳米掺杂相比,直接掺杂助烧剂能够使掺杂元素进入晶格产生离子空位等缺陷,减少了物质迁移所需的活化能,从而有效促进陶瓷致密化过程,显著改善陶瓷的微观形貌及其介电性能。陶瓷样品的介电常数随着LSO助烧剂掺杂量的增加先增大后减小;当助烧剂掺杂量为0.08%(摩尔分数)时,样品可在1200℃烧结,室温介电常数达到4855,且容温特性满足X7R标准。通过直接掺杂能够使助烧剂十分均匀地分布在陶瓷材料中,可以显著减少助烧剂的用量,达到明显降低烧结温度的目的,并起到助烧兼改性的作用。 展开更多
关键词 纳米掺杂 直接掺杂 Li2O-SiO2 BATIO3
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铁掺杂高岭石基纳米TiO_2光催化材料及应用研究 被引量:10
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作者 雷绍民 白春华 +2 位作者 曲艺 熊毕华 郝骞 《金属矿山》 CAS 北大核心 2006年第9期42-45,72,共5页
以片状高岭石为基材,采用Fe3+化合和Fe2O3直接热合两种掺杂方法制备铁掺杂高岭石基纳米TiO2光催化材料。应用结果表明,两种掺杂方式均不同程度地提高了材料的光催化活性,且在自然光下的催化效果也有明显提高。该研究对矿物负载型光催化... 以片状高岭石为基材,采用Fe3+化合和Fe2O3直接热合两种掺杂方法制备铁掺杂高岭石基纳米TiO2光催化材料。应用结果表明,两种掺杂方式均不同程度地提高了材料的光催化活性,且在自然光下的催化效果也有明显提高。该研究对矿物负载型光催化材料在自然光下降解有机物、抗菌、净化空气的工业应用具有重要意义。 展开更多
关键词 高岭石基材 纳米TiO1 化合掺杂 直接热合掺杂 光催化降解
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电子俘获材料的浓度猝灭 被引量:4
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作者 范文慧 刘英 +2 位作者 王永昌 过晓晖 侯洵 《半导体光电》 CAS CSCD 北大核心 1999年第3期171-174,共4页
利用稀土直接掺杂工艺对电子俘获材料 Ca S: Eu , Sm 进行了配方优化,确定了最佳的激活剂浓度,并结合光谱测试,分析了引起 Ca S: Eu , Sm
关键词 电子俘获材料 稀土直接掺杂工艺 浓度猝灭
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CaS∶Eu,Sm及其在农用转光膜上的应用原理 被引量:15
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作者 叶孔敦 光昭 范文慧 《光子学报》 EI CAS CSCD 北大核心 2001年第4期487-491,共5页
利用稀土直接掺杂工艺合成了一种“常光充能”型电子陷获材料 Ca S∶Eu,Sm,它不仅具有 Ca S∶ Eu无机发光材料的荧光光谱特性 ,而且具有红外升频转换特性 ,可将 0 .8~1 .6μm的红外光直接转换为~ 672 nm的红光、量子效率高达 76% ,是... 利用稀土直接掺杂工艺合成了一种“常光充能”型电子陷获材料 Ca S∶Eu,Sm,它不仅具有 Ca S∶ Eu无机发光材料的荧光光谱特性 ,而且具有红外升频转换特性 ,可将 0 .8~1 .6μm的红外光直接转换为~ 672 nm的红光、量子效率高达 76% ,是一种优于 Ca S∶ Eu的光转换农膜添加剂 .而共掺 Eu2 +、Sm3+和 Cu+的 Ca S荧光粉有望成为一种性能优于光转换农膜添加剂 Ca S∶ Eu2 +,Cu+。 展开更多
关键词 稀土直接掺杂工艺 电子陷获材料 红外升频转换 叶绿素 光合作用 植物生理 CaS:Eu Sm 荧光光谱特性 农用转光膜
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一种高效便捷的红外探测卡
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作者 叶孔敦 光昕 范文慧 《化学研究与应用》 CAS CSCD 北大核心 2001年第6期695-698,共4页
Electron trapping material CaS:Eu,Sm has been prepared by the technique of direct doping rare earth.It can convert infrared light (0.8~1.6μm) to visible light (~672nm) and its quantum efficiency is more than 76%.Hi... Electron trapping material CaS:Eu,Sm has been prepared by the technique of direct doping rare earth.It can convert infrared light (0.8~1.6μm) to visible light (~672nm) and its quantum efficiency is more than 76%.High efficiency and portable cards for infrared laser detection have been made of electron trapping material by using various expertiese and tested on many conditions,such as waterlogging at high and low temperature.According to the test,this kind of infrared detecting card can convert infrared light (0.8~1.6μm) to visible light at room temperature efficiently and can be used extensively for adjusting and detecting infrared laser emitted by YAG,GaAs,InGaAsP. 展开更多
关键词 稀土直接掺杂工艺 电子俘获材料 红外上转换 红外探测卡 红外探测材料
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Defect-assisted surface modification enhances the visible light photocatalytic performance of g-C_3N_4@C-TiO_2 direct Z-scheme heterojunctions 被引量:18
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作者 Xibao Li Jie Xiong +2 位作者 Ying Xu Zhijun Feng Juntong Huang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第3期424-433,共10页
To increase the number of active sites and defects in TiO2 and promote rapid and efficient transfer of photogenerated charges, a g-C3N4@C-TiO2 composite photocatalyst was prepared via in situ deposition of g-C3N4 on a... To increase the number of active sites and defects in TiO2 and promote rapid and efficient transfer of photogenerated charges, a g-C3N4@C-TiO2 composite photocatalyst was prepared via in situ deposition of g-C3N4 on a carbon-doped anatase TiO2 surface. The effects of carbon doping state and surface modification of g-C3N4 on the performance of g-C3N4@C-TiO2 composite photocatalysts were studied by X-ray diffraction, X-ray photoelectron spectroscopy, UV-visible diffuse-reflectance spectroscopy, transmission electron microscopy, electrochemical impedance spectroscopy, photoluminescence, and electron paramagnetic resonance. With increasing carbon doping content, the carbon doping state in TiO2 gradually changed from gap to substitution doping. Although the number of oxygen vacancies gradually increased, the degradation efficiency of g-C3N4@C-TiO2 for RhB (phenol) initially increased and subsequently decreased with increasing carbon content. The g-C3N4@10C-TiO2 sample exhibited the highest apparent reaction rate constant of 0.036 min儃1 (0.039 min儃1) for RhB (phenol) degradation, which was 150 (139), 6.4 (6.8), 2.3 (3), and 1.7 (2.1) times higher than that of pure TiO2, 10C-TiO2, g-C3N4, and g-C3N4@TiO2, respectively. g-C3N4 was grown in situ on the surface of C-TiO2 by surface carbon hybridization and bonding. The resultant novel g-C3N4@C-TiO2 photocatalyst exhibited direct Z-scheme heterojunctions with non-local impurity levels. The high photocatalytic activity can be attributed to the synergistic effects of the improved visible light response ability, higher photogenerated electron transfer efficiency, and redox ability arising from Z-type heterojunctions. 展开更多
关键词 PHOTOCATALYST HETEROJUNCTION Direct Z-scheme Doping Modification
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Preparation and characterization of La_(1-x)Ce_xFe_(1-y-n)Co_yRu_nO_3 compounds
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作者 李丽 张密林 +3 位作者 袁福龙 史克英 张国 付宏刚 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2006年第4期498-501,共4页
The mixed oxides La1 -xCexFe1-y-nCOyRunO3 were prepared by sol-gel method and used as catalysts for NO direct decomposition. The catalysts were characterized by DTA - TG, XRD, IR and BET. XRD analysis reveals that th... The mixed oxides La1 -xCexFe1-y-nCOyRunO3 were prepared by sol-gel method and used as catalysts for NO direct decomposition. The catalysts were characterized by DTA - TG, XRD, IR and BET. XRD analysis reveals that the samples are in a pure perovskite phase in 550 - 650 ℃, and catalyst structure keeps long else 20 decrease, and lattice parameters enhance when Ru is introduced. The characteristic peaks of samples are stronger during a temperature increase, and the particle size grows faster. IR analysis shows that the position and shape of adsorption peaks are almost the same among all samples, but with the Ru content increasing, 600 cm^-1 peak stretches to a high frequency and changes to disorder. The wave numbers move to low frequency when n = 0. 05, yet it doesn' t vary obviously when n 〉 0. 05. The BET surface area testifies that particle sizes of all catalysts increase with temperature increasing. 展开更多
关键词 sol-gel preparation DOPING perovskite type phase direct decomposition of NO
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高功率光纤激光器和放大器的非线性效应管理新进展 被引量:14
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作者 廖素英 巩马理 《激光与光电子学进展》 CSCD 北大核心 2007年第6期27-33,共7页
受激布里渊散射、受激拉曼散射、自相位调制等非线性效应限制了高功率光纤激光器、放大器的输出功率和传输特性。通过改进光纤的几何结构、材料成分、制作工艺、工作环境等可以克服这些限制。在分析了光纤激光器、放大器中几种非线性效... 受激布里渊散射、受激拉曼散射、自相位调制等非线性效应限制了高功率光纤激光器、放大器的输出功率和传输特性。通过改进光纤的几何结构、材料成分、制作工艺、工作环境等可以克服这些限制。在分析了光纤激光器、放大器中几种非线性效应的产生机理、功率阈值特点后,着重介绍了采用大模场光纤设计、变化光纤掺杂成分及分布、纳米粒子直接掺杂技术以及控制应力、温度场调制等新方法、新技术在非线性效应管理中的应用,最后指出合理的方案。 展开更多
关键词 非线性效应管理 大模面积光纤 纳米粒子直接掺杂 功率阈值 光子晶体光纤
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Direct synthesis of parallel doped N-MoP/N-CNT as highly active hydrogen evolution reaction catalyst 被引量:6
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作者 Juntao Zhang Rui Sui +4 位作者 Yanrong Xue Xingdong Wang Jiajing Pei Xin Liang Zhongbin Zhuang 《Science China Materials》 SCIE EI CSCD 2019年第5期690-698,共9页
Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped ... Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped molybdenum phosphide nanoparticles(NPs)supported on nitrogen doped carbon nanotubes(N-MoP/N-CNTs). The NH4H2PO2 as a bifunctional agent severs as both phosphidation agent and nitrogen source, which makes the synthetic route simple and efficient. The as-obtained parallel doped N-MoP/N-CNTs show an overpotential of 103±5 mV at 10 mA cm-2, which is 140 mV lower than that of MoP NPs. The enhanced HER performance is attributed to the electronic effect by doped MoP and CNTs supports. This work provides a facile route to synthesize doped phosphides for the potential applications in hydrogen energy. 展开更多
关键词 bifunctional precursor ammonium hypophosphite nitrogen-doped MoP nitrogen-doped carbon nanotubes hydrogen evolution reaction
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