Multifunctional silicon-based light emitting device in standard complementary metal oxide semiconductor technology

A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit visible to near infra-red （NIR） light （the spectrum ranges from 500 nm to 1000 nm） in reverse bias avalanche breakdown mode with working voltage between 8.35 V-12 V and emit NIR light （the spectrum ranges from 900 nm to 1300 nm） in the forward injection mode with working voltage below 2 V. An apparent modulation effect on the light intensity from the polysilicon gate is observed in the forward injection mode. Furthermore, when the gate oxide is broken down, NIR light is emitted from the polysilicon/oxide/silicon structure. Optoelectronic characteristics of the device working in different modes are measured and compared. The mechanisms behind these different emissions are explored.

Study on Property of Salicylaldehyde Schiff Base Metal Complexes for Catalytic Oxidation of Model Sulfides

Seven kinds of Schiff base metal complexes(C1-C7)were synthesized by the reaction of substituted salicylaldehyde Schiff base with cobalt nitrate,nickel nitrate,and copper nitrate,respectively.The oxygen carrying performance,and the catalytic property of complexes for the oxidation of model sulfides 1-hexanethiol,dibutyl sulfide,and 2-methylthiophene along with their influencing factors were explored,while the oxidized products of the model sulfides were also analyzed and characterized.The results show that the catalytic oxidation property of the complexes is determined by their oxygen carrying performance and solubility in n-octane.The oxygen carrying performance of the complexes is mainly affected by the central ion species,the electronic effects,and the spatial effects of the substituents as well as the degree of conjugation.More specifically,the oxygen carrying performance can be improved by enhancing the oxygenation capacity of the central metal ions,increasing the electron donating ability of the ligand substituent,and diminishing the steric hindrance as well as extending the conjugated chain.Complexes C7 were found to be with high oxygen carrying capacity and high solubility in n-octane,which shows the best catalytic oxidation property,and the oxidation conversion rates for 1-hexylthiol,dibutyl sulfide,and 2-methylthiophene are 74.2%,65.1%,and 22.7%,respectively.Upon using the oxidation catalyst of Schiff base metal complexes,three sulfides can be oxidized by oxygen to form sulfones and sulfoxides.1-Hexanethiol and dibutyl sulfide will continue to be oxidized to form sulfates and sulfites.

Selective Oxidation of CO in Excess H_2 over Ru/Al_2O_3 Catalysts Modified with Metal Oxide

The Ru/Al2O3 catalysts modified with metal oxide （K20 and La2O3） were prepared v/a incipient wetness impregnation method from RuCl3.nH2O mixed with nitrate loading on Al2O3 support. The activity of catalysts was evaluated under simulative conditions for the preferential oxidation of CO （CO-PROX） from the hydrogen-rich gas streams produced by reforming gas, and the performances of catalysts were investigated by XRD and TPR. The results showed that the activity temperature of the modified catalysts Ru-K20/Al2O3 and Ru-La2O3/Al2O3 were lowered approximately 30℃ compared with pure Ru/Al2O3, and the activity temperature range was widened. The conversion of CO on Ru-K20/Al2O3 and Ru-La2O3/Al2O3 was above 99% at 140-160℃, suitable to remove CO in a hydrogen-rich gas and the selectivity of Ru-La2O3/Al2O3 was higher than that of Ru-K2O/Al2O3in the active temperature range. Slight methanation reaction was detected at 220℃ and above.

Influence of alkali metal doping on surface properties and catalytic activity/selectivity of CaO catalysts in oxidative coupling of methane

Surface properties （viz. surface area, basicity/base strength distribution, and crystal phases） of alkali metal doped CaO （alkali metal/Ca= 0.1 and 0.4） catalysts and their catalytic activity/selectivity in oxidative coupling of methane （OCM） to higher hydrocarbons at different reaction conditions （viz. temperature, 700 and 750 ℃; CH4/O2 ratio, 4.0 and 8.0 and space velocity, 5140-20550 cm^3 ·g^-1·h^-1） have been investigated. The influence of catalyst calcination temperature on the activity/selectivity has also been investigated. The surface properties （viz. surface area, basicity/base strength distribution） and catalytic activity/selectivity of the alkali metal doped CaO catalysts are strongly influenced by the alkali metal promoter and its concentration in the alkali metal doped CaO catalysts. An addition of alkali metal promoter to CaO results in a large decrease in the surface area but a large increase in the surface basicity （strong basic sites） and the C2＋ selectivity and yield of the catalysts in the OCM process. The activity and selectivity are strongly influenced by the catalyst calcination temperature. No direct relationship between surface basicity and catalytic activity/selectivity has been observed. Among the alkali metal doped CaO catalysts, Na-CaO （Na/Ca = 0.1, before calcination） catalyst （calcined at 750 ℃）, showed best performance （C2＋ selectivity of 68.8% with 24.7% methane conversion）, whereas the poorest performance was shown by the Rb-CaO catalyst in the OCM process.

Additive effects of alkaline-earth metals and nickel on the performance of Co/γ-Al_2O_3 in methane catalytic partial oxidation

Nano-sized γ-alumina （γ-Al2O3） was first prepared by a precipitation method. Then, active component of cobalt and a series of alkaline- earth metal promoters or nickel （Ni） with different contents were loaded on the γ-Al2O3 support. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction （XRD） and thermogravimetry analysis （TGA）. The activity and selectivity of the catalysts in catalytic partial oxidation （CPO） of methane have been compared with Co/γ-Al2O3, and it is found that the catalytic activity, selectivity, and stability are enhanced by the addition of alkaline-earth metals and nickel. The optimal loadings of strontium （Sr） and Ni were 6 and 4 wt%, respectively. This finding will be helpful in designing the trimetallic Co-Ni-Sr/γ-Al2O3 catalysts with high performance in CPO of methane

Fabrication and Characterization of Glass-Ceramics Doped with Rare Earth Oxide and Heavy Metal Oxide

Cordierite-based glass-ceramics with non-stoichiometric composition doped with rare earth oxide (REO_2) and heavy metal oxide (M_2O_3) respectively were fabricated from glass powders. After sintering and crystallization heat treatment, various physical properties, including compact density and apparent porosity, were examined to evaluate the sintering behavior of cordierite-based glass-ceramics. Results show that the additives both heavy metal oxide and rare earth oxide promote the sintering and lower the phase temperature from μ- to α-cordierite as well as affect the dielectric properties of sintered glass-ceramics. The complete-densification temperature for samples is as low as 900 ℃. The materials have a low dielectric constant (≈5), a low thermal expansion coefficient ((2.80～3.52)×10^(-6) ℃^(-1)) and a low dissipation factor (≤0.2%) and can be co-fired with high conductivity metals such as Au, Cu, Ag/Pd paste at low temperature (below 950 ℃), which makes it to be a promising material for low-temperature co-fired ceramic substrates.

Current Progress of Hf(Zr)-Based High-k Gate Dielectric Thin Films

With the continued downscaling of complementary metal-oxide-semiconductor field effect transistor dimensions, high-dielectric constant （high-k） gate materials, as alternatives to SiO2, have been extensively investigated. Hf （Zr）-based high-k gate dielectric thin films have been regarded as the most promising candidates for high-k gate dielectric according to the International Technology Roadmap for Semiconductor due to their excellent physical properties and performance. This paper reviews the recent progress on Hf （Zr）-based high-k gate dielectrics based on PVD （physical vapor deposition） process. This article begins with a survey of various methods developed for generating Hf （Zr）-based high-k gate dielectrics, and then mainly focuses on microstructure, synthesis, characterization, formation mechanisms of interfacial layer, and optical properties of Hf （Zr）-based high-k gate dielectrics. Finally, this review concludes with personal perspectives towards future research on Hf （Zr）-based high-k gate dielectrics.

A unified charge-based model for SOI MOSFETs applicable from intrinsic to heavily doped channel

A unified charge-based model for fully depleted silicon-on-insulator （SOI） metal oxide semiconductor field-effect transistors （MOSFETs） is presented. The proposed model is accurate and applicable from intrinsic to heavily doped channels with various structure parameters. The framework starts from the one-dimensional Poisson Boltzmann equa- tion, and based on the full depletion approximation, an accurate inversion charge density equation is obtained. With the inversion charge density solution, the unified drain current expression is derived, and a unified terminal charge and intrinsic capacitance model is also derived in the quasi-static case. The validity and accuracy of the presented analytic model is proved by numerical simulations.

金属基磷化物纳米材料制备与电催化应用研究进展

处于纳米尺度的磷化物及其与贵金属构成的复合材料具有独特的物理和化学性质,在电催化领域有广泛应用。例如,在甲醇电催化氧化反应中,由于磷(P)比金属铂(Pt)或钯(Pd)等具有更大的电负性,金属原子的外层电子被P吸引而偏向P原子,从而间接提高了Pt或Pd对CO类中间产物的耐受性;在电解水析氢反应中,P可以作为质子受体,增强H^(+)在金属上的吸附,从而促进析氢反应;在电解水析氧反应中,金属基磷化物容易被氧化成氧化物和氢氧化物,从而形成氧化物/氢氧化物-磷化物界面,进一步促进析氧反应。纳米颗粒的催化性能很大程度上取决于催化剂的结构、组分、组分之间的相互作用以及活性位点的电子结构,因此,对金属基磷化物基纳米复合材料的这些性质进行合理调控是提升其电催化性能的关键。本文所综述的材料范围包含金属基磷化物本身及其与贵金属构成的纳米复合材料,首先概括介绍金属基磷化物基纳米复合材料的合成方法和表征技术,进而阐述如何利用复合材料中晶格应变和电子耦合等物理效应提升电催化活性和稳定性。最后,围绕金属基磷化物基纳米复合材料电催化性能进一步提升的问题,对其未来合成策略和发展进行展望。

负载铁系金属氧化物催化次氯酸钠降解酸性大红的实验研究

酸性大红是一种性能良好的染料,也是一种难以治理的工业废水,但由于它在水中溶解度较高,通常难以通过简单方法直接进行处理。次氯酸钠为多功能强氧化剂,安全无毒,但稳定性不高,对氧化活性的利用不够,对酸性大红染料的去除能力有限。通过负载铁系金属氧化物来催化次氯酸钠对酸性大红染料进行降解,从而高效率提供分子反应动能,提高其氧化性;考察pH值、催化剂投入量、反应时间、次氯酸钠用量、负载催化剂量等对酸性大红的降解作用,得出最佳处理条件。结果显示:①采用沉淀—负载法,随着负载量增加,硅藻土图谱上的CoFe_(2)O_(4)峰越来越明显,完成了有效负载;②在pH值为4、反应时间为25 min、催化剂投加量为0.7 g、负载催化剂量达到30%、次氯酸钠溶液为5 mL时,降解酸性大红效果最显著;③对比次氯酸钠和芬顿试剂氧化降解酸性大红发现,次氯酸钠对酸性大红的去除率比芬顿试剂高;④在实际生产废水降解实验中,使用负载铁系金属氧化物催化次氯酸钠降解酸性大红和COD的效果十分显著,用此方法对废水中的酸性大红和COD的去除率分别为90%和83%。

基于电子式电压互感器边界特性分析的35 kV配网输电线路单端暂态量保护方案及其整定

随着分布式电源广泛接入配电网,传统三段式电流保护方案的性能严重劣化。单端暂态量边界保护由于具备不依赖电源特性等突出优势,有望成为改善主动配电网保护配置性能的有效方案,但其需依附于线路边界强健的滤波作用。为此,该文研究发现,可利用智能变电站和智能开闭所中电子式电压互感器、金属氧化物避雷器与其余设备杂散电容共同作为线路边界,其优异的高频滤波作用能够为暂态量保护方案的设计奠定基础;其次,利用区内外故障时电压行波高频频带能量差异构造保护判据,并基于整定门槛与动作时序的合理配合形成单端暂态量阶段式保护方案;最后,基于PSCAD仿真平台验证所提方案的有效性、灵敏性与可靠性,其可与电流保护方案协同互济以强化主动配电网继电保护方案的动作性能。

离子液体多酸在燃油氧化脱硫中的研究进展

氧化脱硫,因其反应条件温和、成本较低等特点被广泛应用于燃油脱硫领域。近年来,有研究者发现离子液体中的阴阳离子结构具有可调性,可借此通过物理化学法制备出高效的催化剂,为更深度的氧化脱硫提供有利条件。本文总结了离子液体多酸的合成与分类,详细叙述了单纯离子液体多酸和以金属有机框架或无机非金属材料为载体的负载型离子液体多酸的特点以及目前其在燃油氧化脱硫领域的研究进展,包括脱硫率和重复使用次数等脱硫效果。单纯离子液体多酸的初次脱硫效率都在80%以上,最高可达99.2%,而负载后的离子液体多酸的脱硫率都在98%以上,大多数高达100%,重复利用次数最高可达13次。众多研究者一致认为负载型离子液体多酸不仅能有效增强多酸的催化活性,而且可提高催化剂的热稳定性与重复利用性,在燃油氧化脱硫中有着良好的使用效果。最后对离子液体多酸在氧化脱硫领域的发展方向提出了展望,指出了具有良好催化性能、可重复利用性好、绿色高效的离子液体多酸是未来的研究方向,为进一步研究离子液体多酸提供了参考。

金属支撑型固体氧化物电解池的3D建模与性能分析

建立了一种铈基电解质的金属支撑型固体氧化物电解池的三维模型,通过多物理场耦合分析了其电化学工作性能.设计的3层电解质结构为10Sc1CeSZ|GDC|10Sc1CeSZ,以GDC为主电解质.针对连接体、流体域和多层单电池结构建立了三维模型,将质量、动量、能量控制方程与物质输运方程和电化学反应耦合建立多物理场分析模型.研究了设计的金属支撑型固体氧化物电解池的电化学工作性能,详细分析了电池内部的速度场、浓度场和温度场分布.结果表明,设计的金属支撑型固体氧化物电解池在650℃下,电流密度为2.4 A/cm^(2)时,电压损失为0.38 V,欧姆损失和极化损失分别占33.72%和66.28%.采用金属支撑对气体的输运仅有轻微的影响,但是整个电池内部的温度分布均匀性得到明显改善.

二氧化硅基气凝胶材料及其制备技术的专利分析

气凝胶为多功能新型材料,其中二氧化硅基气凝胶是研究最广泛的气凝胶材料,2004年首次在中国产业化,至今被广泛应用于电子、建筑、隔热、航空航天、能源等领域中。但与国外相比,中国高端产品较少,原始创新略显不足。因此,本文梳理了近20年全球二氧化硅基气凝胶材料及其制备技术的相关专利,从专利的视角挖掘近20年的研究热点。从市场流向和重点申请人的维度分析当前的市场竞争格局,指出以美、德、日为代表的发达国家,通过全球专利布局在一定程度上实现了对市场较大力度的控制,处于领先地位。重点从技术热点及技术路线的角度分析二氧化硅基气凝胶及其制备技术的研究热点:目前,气凝胶颗粒、前体的改进和纤维增强是近年来该领域的研究重点,各国对金属氧化物复合材料和透明储能材料的关注度较高。并且通过梳理中国的转移转化专利的技术特点,帮助企业在寻求技术合作时精准找到合作对象。最后总结了技术创新中中国企业需重点关注的研究方向,为未来的技术研发提供指引。

磷酸改性CeO_(2)纳米棒负载Pt催化剂催化丙烷燃烧性能的研究

机动车和石油化工等污染源排放造成的环境污染日益严重,其中以丙烷为代表的低碳烷烃结构稳定,难以实现低温完全氧化,亟需开发高效低碳烷烃低温催化氧化催化剂。以氧化铈纳米棒为载体,通过酸改性合成不同量磷酸改性的1%Pt/CeO_(2)-y POx催化剂,发现磷酸改性之后丙烷催化燃烧T_(50)降低了60℃。通过XRD、TEM、EDS mapping等表征发现Pt和P均匀分布在氧化铈表面,且在磷酸改性和Pt负载过程后,氧化铈结构保持稳定。XPS和原位CO-DRIFTs表征结果表明磷酸改性之后,Pt在催化剂表面颗粒大小随磷酸改性程度增加而逐渐变大,并存在最优的Pt^(2+)和Pt^(4+)比,有利于丙烷在催化剂表面吸附和反应。H_(2)-TPR和NH_(3)-TPD表征结果表明,磷酸改性之后,催化剂表面产生了大量的酸性位,而磷酸改性并未大幅降低催化剂的氧化还原能力,从而提高了铈基催化剂的丙烷燃烧活性。

过渡金属活化过硫酸盐去除水中抗生素研究进展

基于活化过硫酸盐的高级氧化技术能够产生强有效的硫酸根自由基(·SO_(4)^(-))和羟基自由基(·OH)使水中的抗生素矿化降解。过渡金属活化过硫酸盐因具有环保、高效的优点而表现出良好的活化效果。单一的金属离子,如Ag+、Fe^(2+)、Co^(2+)、Zn^(2+)、Mn^(2+)、Ni^(2+)参与循环活化较为困难,因此本文重点讨论了目前多金属氧化物、碳基负载过渡金属、光协同过渡金属活化过硫酸盐去除水中抗生素的研究进展,以期对水中有机污染物的去除提供思路。多金属氧化物在活化过程中其他金属离子可作为电子供体实现变价循环;碳基负载过渡金属通过自由基和非自由基反应降解抗生素,在活化过程中能够减缓金属表面发生电化学氧化和物理团聚,促进电子转移;光协同过渡金属活化促进光生空穴与光生电子的分离,提高活化效果。

碳基复合材料用于钠离子电池负极研究进展

相对于锂离子电池,钠离子电池成本低、高低温性能优异、安全性高,而且钠资源丰富,具有广阔的应用前景和发展潜力。钠离子电池技术关键在于高性能负极材料。目前,钠离子电池的负极材料主要有碳基材料,层状氧化物,钛基材料,过渡金属氧化物等。其中,碳基材料具有结构稳定、高容量以及污染小等特点被作为钠离子负极材料进行广泛研究。综述了对碳基复合材料钠离子电池负极研究进展。

3D-Ni_(3)S_(2)微球电催化尿素氧化辅助制氢研究

电催化尿素氧化(UOR)替代动力学缓慢的析氧反应(OER)为高效制氢提供了新的思路。本研究通过简单的二次水热法制备了三维Ni_(3)S_(2)/NF微球催化剂(3D-Ni_(3)S_(2)/NF),由于独特的3D结构为UOR提供了高度开放的活性区域,并加快了电荷转移速率,3D-Ni_(3)S_(2)/NF表现出明显优于1D,2D-Ni_(3)S_(2)/NF电催化氧化尿素的活性。在1 mol L^(-1)KOH+0.33 mol L^(-1)尿素电解质溶液,3D-Ni_(3)S_(2)/NF电催化尿素氧化达到100 mA cm^(-2)的电流密度的电位仅需1.38 V vs.RHE,比OER电位减少了250 mV,同时在24 h稳定性测试中表现出良好的耐久性。此外,全尿素辅助制氢只需1.66 V即可达到50 mA cm^(-2),表现出比传统电解水(1.86 V)更低的电位。

单原子催化剂的合成及在环境治理中的研究进展

在污染日趋严重的今天,环境催化技术愈发重要。催化剂催化性能与其活性位点息息相关,传统纳米催化剂因原子间堆叠导致有效活性位点不足。近年来,具有单位点、100%原子利用率及特殊电子结构的单原子催化剂(SACs)受到广泛关注,有望提高反应催化效率。总结了SACs的合成策略,梳理了其近年来在CO_(2)还原、CH_(4)部分氧化及有机物降解等环境领域的应用,并对其未来发展进行展望。

镓基液态金属颗粒的过冷和氧化行为研究进展

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