期刊文献+
共找到10篇文章
< 1 >
每页显示 20 50 100
核化密度对硅上生长异质外延金刚石膜的影响 被引量:1
1
作者 廖克俊 王万录 《微细加工技术》 1997年第4期37-42,共6页
本文利用扫描电子显微镜及Raman谱等研究了Si(100)上异质外延金刚石膜的生长.金刚石膜是由微波等离子体CVD法制备的。实验结果表明核化密度对Si(100)上异质外延金刚石膜生长有重要的影响.过低或过高的核化密度都不可能形成异质外... 本文利用扫描电子显微镜及Raman谱等研究了Si(100)上异质外延金刚石膜的生长.金刚石膜是由微波等离子体CVD法制备的。实验结果表明核化密度对Si(100)上异质外延金刚石膜生长有重要的影响.过低或过高的核化密度都不可能形成异质外延金刚石膜。 展开更多
关键词 金刚石膜 核化密度 CVD法 外延生长
下载PDF
离子轰击对金刚石核形成能影响的理论探讨
2
作者 徐幸梓 刘天模 王必本 《重庆大学学报(自然科学版)》 EI CAS CSCD 北大核心 2001年第5期107-110,共4页
金刚石核化是制备金刚石薄膜的关键。目前 ,负偏压是增强金刚石核化最有效的方法。本工作着重计算了在负偏压增强金刚石核化的过程中 ,金刚石在离子对衬底表面进行轰击导致衬底表面产生微缺陷 (凹坑 )上成核的形成能 ,给出了金刚石的核... 金刚石核化是制备金刚石薄膜的关键。目前 ,负偏压是增强金刚石核化最有效的方法。本工作着重计算了在负偏压增强金刚石核化的过程中 ,金刚石在离子对衬底表面进行轰击导致衬底表面产生微缺陷 (凹坑 )上成核的形成能 ,给出了金刚石的核化能 ,核化密度以及核化速率与凹坑密度的解析函数。结果表明金刚石的核化能随凹坑密度的增大而降低 ,从而导致核化密度及核化速率的提高 ,与文献中的实验结果相一致。分析和讨论了凹坑降低金刚石核形成能的原因。 展开更多
关键词 金刚石 形成能 凹坑 离子轰击 金刚石 核化密度 速率 薄膜
下载PDF
基于飞秒激光改性表面核化点密度研究
3
作者 唐吴宇 周磊 +1 位作者 张君毅 闫晓 《核动力工程》 EI CAS CSCD 北大核心 2022年第5期95-99,共5页
以不锈钢材料为实验件,采用飞秒激光技术加工有序微纳结构来制备改性表面,并以去离子水为工质开展池沸腾核化点密度实验研究,获取了不同热工参数条件下3种不同实验表面(常规表面、改性表面1、改性表面2)的核化点密度实验数据,定量分析... 以不锈钢材料为实验件,采用飞秒激光技术加工有序微纳结构来制备改性表面,并以去离子水为工质开展池沸腾核化点密度实验研究,获取了不同热工参数条件下3种不同实验表面(常规表面、改性表面1、改性表面2)的核化点密度实验数据,定量分析了核化点密度随壁面过热度的变化规律,并以李权模型为基础拟合得到改进核化点密度模型。研究发现,3种实验表面的核化点密度均随壁面过热度的升高而增大,且相同热工参数下改性表面的核化点密度显著大于常规表面;改进模型优化了核化点密度的预测值,且预测值与实验数据吻合较好。 展开更多
关键词 密度 池沸腾 飞秒激光 改性表面 改进模型
原文传递
基于DM6437的运动目标检测系统 被引量:2
4
作者 周建雄 张笑微 《信息化纵横》 2009年第12期54-57,61,共5页
采用非参数化的核密度估计完成背景减法,设计了基于高端数字媒体处理器KM6437的实时运动目标检测系统。提出了一种有效的背景更新策略,使得背景的更新更加可靠,提高了检测的精确度。实验表明该系统能够对目标进行比较实时和准确的检测。
关键词 DM6437 非参数密度估计 背景更新
下载PDF
光学镀膜与装置
5
《中国光学》 EI CAS 1999年第1期61-62,共2页
O484.1 99010388等离子体增强热丝CVD法生长cBN薄膜中的衬底效应=Substrate effects in the formation of c—BNsynthesis by plasma assisted hot—filamentchemical vapour deposition[刊,中]/陈光华,严辉(北京工业大学应用物理系.北... O484.1 99010388等离子体增强热丝CVD法生长cBN薄膜中的衬底效应=Substrate effects in the formation of c—BNsynthesis by plasma assisted hot—filamentchemical vapour deposition[刊,中]/陈光华,严辉(北京工业大学应用物理系.北京(100022)),张兴旺。 展开更多
关键词 异质外延金刚石膜 人工晶体 等离子体增强 超硬材料 薄膜沉积 应用物理 国家重点实验室 吉林大学 薄膜生长 核化密度
下载PDF
基于DM6437的动态目标检测算法研究
6
作者 赵晨萍 王应军 郭运瑞 《福建电脑》 2010年第6期6-7,共2页
基于TI公司的高端数字媒体处理器DM6437,设计了一种实时动态目标检测系统。采用非参数核密度估计方法,对静止和动态背景下动态目标检测算法进行了研究和分析,指出了算法的有效性和实用性。
关键词 动态目标 检测 非参数密度估计 DM6437
下载PDF
DFT Study on Electronic Structures and Spectroscopic Properties of Oligo(silanylenediethynylanthracene)
7
作者 张培斌 黄昕 +1 位作者 李歆 滕启义 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第1期25-30,I0003,共7页
Poly(silanylenediethynylanthracene) (PSDEA) exhibits a hole-transporting ability experimentally. In order to simulate the property of PSDEA, a series of silanylenediethynylanthracene oligomers were designed. The s... Poly(silanylenediethynylanthracene) (PSDEA) exhibits a hole-transporting ability experimentally. In order to simulate the property of PSDEA, a series of silanylenediethynylanthracene oligomers were designed. The structures of these oligomers were optimized by using density function theory at B3LYP/6-31G(d) level. The energy gaps of the oligomers decrease with the increase in the chain length. The energy gaps of the oligomers also decrease in the presence of the electron-withdrawing group on the anthracene ring. The 13C chemical shifts and nucleus independent chemical shifts (NICS) at the anthracene ring center in the oligomers were calculated at B3LYP/6-31G level. The chemical shifts of the carbon atoms connected with the nitryl group changed upfield, compared with those of the carbon atoms without the nitryl group. The aromaticity at the anthracene ring center decreases in the presence of the electron-withdrawing group, whereas increases with the increase in the number of the silanylene units. The most sensitive location for calculating the NICS values is 0.1 nm above the anthracene plane. 展开更多
关键词 Silanylenediethynylanthracene oligomer Conductive polymer Nucleus independent chemical shift scanning Density function theory
下载PDF
Engineering Ru(IV)charge density in Ru@RuO2 core-shell electrocatalyst via tensile strain for efficient oxygen evolution in acidic media 被引量:5
8
作者 Yizhi Wen Tao Yang +3 位作者 Chuanqi Cheng Xueru Zhao Enzuo Liu Jing Yang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第8期1161-1167,共7页
The design of efficient Ru-based electrocatalysts with high intrinsic activities for acidic water oxidation is highly desirable and challenging for water splitting in proton exchange membrane electrolyzers.Here,for th... The design of efficient Ru-based electrocatalysts with high intrinsic activities for acidic water oxidation is highly desirable and challenging for water splitting in proton exchange membrane electrolyzers.Here,for the first time,we engineer the charge density of Ru(IV)by creating tensile strains in the RuO2 shell of Ru@RuO2 core-shell nanoparticles,viz.Ru@RuO2-L.High-resolution spectroscopic characterizations confirm the presence of av.6%tensile strain in Ru-O bonds,which results in an effective reduction of the Ru(IV)charge density.The resultant Ru^X+(4<X<5)active sites greatly accelerate the oxygen evolution reaction(OER)in an acidic electrolyte,leading to a remarkably low overpotential of 191 mV at 10 mA cm^-2.These values are lower than those for the benchmark RuO2 catalyst and are also among the lowest for efficient Ru-based electrocatalysts reported thus far.The specific activity and mass activity are also greatly enhanced 4.2-fold and 17.7-fold compared to those of RuO2,respectively.The acidic OER activity improvement is ascribed to the lowered adsorption energy of*OOH,owing to the reduced charge density of Ru(IV),and the rapid charge transport owing to the Ru core.Ru@RuO2-L also demonstrates high feasibility as the anode catalyst for the overall water splitting in acidic media. 展开更多
关键词 Tensile strain Core-shell structure Ruthenium oxide Charge density Oxygen evolution reaction Acidic media
下载PDF
Spatial Agglomeration of Exhibition Enterprises on a Regional Scale in China 被引量:1
9
作者 FANG Zhongquan ZHANG Ying +1 位作者 WANG Zhangjun ZHANG Lifeng 《Chinese Geographical Science》 SCIE CSCD 2017年第3期497-506,共10页
During the past two decades, the exhibition industry in China has been developing rapidly and has become an important part of the modern service industry, particularly the agglomeration characteristics of exhibition e... During the past two decades, the exhibition industry in China has been developing rapidly and has become an important part of the modern service industry, particularly the agglomeration characteristics of exhibition enterprises highlighted on the regional scale. Although the development of theoretical research on the western exhibition industry has taken place over time, the spatial perspective has not been at the centre of attention so far. This paper aims to fill this gap and report on the agglomeration characteristics of exhibition enterprises and their influential factors. Based on data about exhibition enterprises in the Pearl River Delta(PRD) during 1991–2013, using the Ripley K function analysis and kernel density estimation, this research identifies that: 1) the exhibition enterprise on the regional scale is significantly characterized by spatial agglomeration, and the agglomeration density and scale are continuously increasing; 2) the spatial pattern of agglomeration has developed from a single-center to multi-center form. Meanwhile, this paper profiles the factors influencing the spatial agglomeration of exhibition enterprises by selecting the panel data of nine cities in the PRD in 1999, 2002, 2006 and 2013. The results show that market capacity, urban informatization level and exhibition venues significantly influence the location choice of exhibition enterprises. Among them, the market capacity is a variable that exerts a far greater impact than other factors do. 展开更多
关键词 exhibition enterprises spatial agglomeration Ripley K function analysis regional scale Pearl River Delta
下载PDF
Exploration of Earth-Abundant Transition Metals(Fe,Co,Ni)Doped on W_(18)O_(49)System as Electrocatalysts for Urea Productiont
10
作者 Kaile Li Changyan Zhu +6 位作者 Xiaohui Yao Ao Yang Yunjie Chu Mengxue Wang Yun Geng Zhongmin Su Min Zhang 《Chinese Journal of Chemical Physics》 SCIE EI CAS 2024年第5期605-613,I0041-I0050,I0099,共20页
The conversion of inert N_(2)and CO_(2)into urea by electrocatalytic technology not only reduces the cost of urea synthesis in future,but also alleviatesthe environmental pollution problem caused by carbon emission in... The conversion of inert N_(2)and CO_(2)into urea by electrocatalytic technology not only reduces the cost of urea synthesis in future,but also alleviatesthe environmental pollution problem caused by carbon emission in traditional industrial production.However,facing downside factors such as strong competitive reactions and unclear reaction mechanism,the design of high-performance urea catalysts is imminent.This study demonstrates that W_(18)O_(49)system doped heteronuclear metals(TM=Fe,Co,Ni)can effectively solve the problem of competitive adsorption between N_(2)and CO_(2)and realize the co-adsorption of N_(2)and CO_(2)at diverse sites.Their theoretical limiting voltages for urea production on TM-W_(18)O_(49)(TM=Fe,Co,Ni)systems are-0.46 V,-0.42 V and-0.52 V,respectively.The results are all lower than that of the contrastive voltage in pristine W_(18)O_(49)system(-0.91 V),further indicating the rationality and necessity of single-atom doped strategy for the co-reduction of two molecules.Specially,Co-W_(18)O_(49)can theoretically inhibit the side reactions of NRR,CO_(2)RR,and HER,which deserve future experimental exploration in future.The study suggests that doping heteronuclear metal into transition metal oxides is a feasible scheme to solve competitive adsorption and improve catalytic performance. 展开更多
关键词 Urea production Competitive adsorption Doping heteronuclear metals TM-W_(18)O_(49)catalysts Density functional theory calculation
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部