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人工神经网络用于炭/炭复合材料CVDSiC涂层的研究 被引量:5
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作者 李贺军 徐志淮 《炭素技术》 CAS CSCD 1999年第2期17-20,共4页
炭/炭复合材料抗氧化涂层是该材料可否用于高温结构件的关键。将人工神经网络用于CVDSiC抗氧化涂层的建模,试图解决该过程影响因素复杂、数学模型难于建立、无法对整个过程进行有效预测和控制的问题。初步探讨表明,采用人工神... 炭/炭复合材料抗氧化涂层是该材料可否用于高温结构件的关键。将人工神经网络用于CVDSiC抗氧化涂层的建模,试图解决该过程影响因素复杂、数学模型难于建立、无法对整个过程进行有效预测和控制的问题。初步探讨表明,采用人工神经网络建模,可以比较确切与全面地反映CVDSiC涂层过程的影响因素和内在规律,预测的工艺参数与沉积速率的关系同实验结果吻合较好。 展开更多
关键词 化学气相沉积 神经网络 涂层 炭/炭复合材料 CVD
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CVDSiC先驱体的研究进展
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作者 李斌 张长瑞 胡海峰 《材料导报》 EI CAS CSCD 北大核心 2005年第F05期363-365,共3页
从CVD法制备SiC的传统先驱体的缺陷和不足出发,较详细地介绍了目前常用的先驱体体系及先驱体的发展趋势,并归纳新型先驱体应具备的特点。
关键词 SIC CVD 先驱体
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工艺参数对真空紫外光直接光CVDSiO_2/Si界面特性的影响
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作者 谢茂浓 杜开瑛 刘玉荣 《微电子学》 CAS CSCD 北大核心 1998年第3期172-175,共4页
采用高频(1MHz)C-V测试和红外谱,研究了工艺参数对Xe激发真空紫外光(VUV)直接光CVDSiO2的SiO2/Si界面特性的影响。结果表明:衬底温度Ts对固定氧化物电荷密度ΔNot、慢界面态密度ΔNst的影响比... 采用高频(1MHz)C-V测试和红外谱,研究了工艺参数对Xe激发真空紫外光(VUV)直接光CVDSiO2的SiO2/Si界面特性的影响。结果表明:衬底温度Ts对固定氧化物电荷密度ΔNot、慢界面态密度ΔNst的影响比反应室总气压Pc和SiH2/O2分压比显著。ΔNot和ΔNst在110°C附近有极小值,大小为1010cm-2量级。Ts>120°C,ΔNot呈正电荷性,Ts<110°C,ΔNot呈负电荷性。Si-O-Si伸缩振动吸收峰位在1060~1080cm-2间,随Ts的减少而增加。 展开更多
关键词 光CVD 半导体 光化学汽相淀积
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光 CVDSiO_2钝化膜在红外探测器中的应用
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作者 程开富 《半导体光电》 CAS CSCD 北大核心 1989年第2期79-84,90,共7页
本文评述了光 CVD SiO_2钝化膜的原理和方法,介绍了在50~300℃温度下,在 Si、InSb 和 HgCdTe 晶片上光 CVD SiO_2钝化膜。讨论了膜的淀积条件和性质以及光 CVDSiO_2钝化膜在 InSb、HgCdTc 红外探测器中的应用。
关键词 光CVD SIO2膜 红外探测器
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CVDSnO_2薄膜吸附的XPS研究 被引量:1
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作者 吴孙桃 沈 华 +1 位作者 徐富春 蔡玉霜 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 1994年第5期610-613,共4页
利用XPS方法,分析四种由不同CVD温度(250~550℃)淀积在n-Si衬底上形成异质结的SnO_2透明多晶薄膜的表面.定性和半定量分析表明,表面存在三种氧物种,在加热吸附H_2前后,相对含量发生变化,变化大小与制... 利用XPS方法,分析四种由不同CVD温度(250~550℃)淀积在n-Si衬底上形成异质结的SnO_2透明多晶薄膜的表面.定性和半定量分析表明,表面存在三种氧物种,在加热吸附H_2前后,相对含量发生变化,变化大小与制备温度有关.根据实验结果和分析,研究薄膜H_2吸附机理,讨论SnO_2薄膜的气敏与SnO_2/n-Si异质结光伏的关系以及制备温度对薄膜吸附反应性能的影响. 展开更多
关键词 薄膜 XPS 吸附 二氧化锡 CVD
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Nanomaterials based flexible devices for monitoring and treatment of cardiovascular diseases(CVDs)
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作者 Zehua Xiang Mengdi Han Haixia Zhang 《Nano Research》 SCIE EI CSCD 2023年第3期3939-3955,共17页
Cardiovascular diseases(CVDs)are one of the most serious diseases threatening human health in the world.Therefore,effective monitoring and treatment of CVDs are urgently needed.Compared with traditional rigid devices,... Cardiovascular diseases(CVDs)are one of the most serious diseases threatening human health in the world.Therefore,effective monitoring and treatment of CVDs are urgently needed.Compared with traditional rigid devices,nanomaterials based flexible devices open up new opportunities for further development beneficial from the unique properties of nanomaterials which contribute to excellent performance to better prevent and treat CVDs.This review summarizes recent advances of nanomaterials based flexible devices for the monitoring and treatment of CVDs.First,we review the outstanding characteristics of nanomaterials.Next,we introduce flexible devices based on nanomaterials for practical use in CVDs including in vivo,ex vivo,and in vitro methods.At last,we make a conclusion and discuss the further development needed for nanomaterials and monitoring and treatment devices to better care CVDs. 展开更多
关键词 cardiovascular diseases(cvds) MONITORING treatment NANOMATERIALS flexible devices
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Long-term Cumulative Depressive Symptoms and Incident Cardiovascular Disease in Middle-aged and Older Population:Two Cohort Studies
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作者 Fangfei You Yining Gao +11 位作者 Wenfang Zhong Zhihao Li Jian Gao Dong Shen Xiaomeng Wang Weiqi Song Qi Fu Haoyu Yan Jiahao Xie Huan Chen Hao Yan Chen Mao 《Biomedical and Environmental Sciences》 2026年第1期15-25,共11页
Objective Elevated depressive symptoms are well-documented among geriatric adults with cardiovascular disease(CVD);however,few studies have accounted for long-term cumulative depressive symptom exposure.This study det... Objective Elevated depressive symptoms are well-documented among geriatric adults with cardiovascular disease(CVD);however,few studies have accounted for long-term cumulative depressive symptom exposure.This study determined the relationship between cumulative depressive symptoms and CVD.Methods Individual participant data were obtained from the China Health and Retirement Longitudinal Study(CHARLS)and Health and Retirement Study(HRS).Eligible participants had access to assessment information on depressive symptoms and had no history of CVD at baseline.Long-term cumulative depressive symptoms were estimated by calculating the area under the curve based on the Center for Epidemiological Studies Depression Scale.Results Herein,8,861 participants from CHARLS(mean age:58.58 years;male:48.6%)and 7,284 from HRS(60.94 years;35.0%)were enrolled.The median follow-up period was 5 years for the CHARLS and10 years for the HRS.Compared with the first quartile of cumulative depressive symptoms,the HRs(95%CI)in the fourth quartile were 1.73(1.48,2.02)for predicting CVD(P<0.001),1.83(1.52,2.19)for heart disease(P<0.001),1.53(95%CI:1.17,1.99)for stroke(P=0.002)in CHARLS.For HRS,the HRs(95%CI)were 1.41(95%CI:1.27,1.57;P<0.001),1.42(95%CI:1.26,1.59;P<0.001),and 1.30(95%CI:1.06,1.58;P=0.010)respectively.Strong dose-response relationships were observed,with similar results for the two cohorts.Conclusion Long-term cumulative depressive symptoms were significantly associated with incident CVD in middle-aged and older adults,providing insights into controlling long-term depressive symptoms to improve this cohort's health. 展开更多
关键词 Cumulative depressive symptom CVD COHORT CHARLS HRS
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Associations between Premature Menopause and Cardiovascular-Kidney-Metabolic Syndrome:A Prospective Cohort Study from the UK Biobank
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作者 Ming Jin Zeping Yang +5 位作者 Ziyi Zhang Zhexin Luo Ninghao Huang Tao Huang Xiaojing Liu Nan Li 《Biomedical and Environmental Sciences》 2026年第1期105-110,共6页
Cardiovascular disease(CVD)is often accompanied by chronic kidney disease(CKD)and metabolic disorders such as obesity and type 2 diabetes^([1]).The coexistence of these conditions can lead to systemic dysfunction and ... Cardiovascular disease(CVD)is often accompanied by chronic kidney disease(CKD)and metabolic disorders such as obesity and type 2 diabetes^([1]).The coexistence of these conditions can lead to systemic dysfunction and substantially increase adverse cardiovascular outcomes.To describe this interplay,the American Heart Association(AHA)recently proposed the concept of cardiovascular-kidney-metabolic(CKM)syndrome^([1]).However,its risk-enhancing factors and underlying mechanisms remain unclear. 展开更多
关键词 metabolic disorders chronic kidney disease cardiovascular disease chronic kidney disease ckd type diabetes systemic dysfunction premature menopause cardiovascular disease cvd
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心血管病高危人群健康效用测量工具的选择:EQ-5D-5L与SF-6Dv2的应用验证
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作者 孙菊 郭倩 +3 位作者 李浩淼 姚强 祝淑珍 李俊琳 《中国卫生政策研究》 北大核心 2025年第8期20-28,共9页
目的:以我国心血管病(Cardiovascular Diseases,CVD)高危人群筛查与干预项目为应用场景,系统评估EQ-5D-5L和SF-6Dv2量表在心血管病高危人群中的适用性。方法:采用Spearman相关系数比较两量表聚合效度;采用组内相关系数(ICC)、Bland-Alt... 目的:以我国心血管病(Cardiovascular Diseases,CVD)高危人群筛查与干预项目为应用场景,系统评估EQ-5D-5L和SF-6Dv2量表在心血管病高危人群中的适用性。方法:采用Spearman相关系数比较两量表聚合效度;采用组内相关系数(ICC)、Bland-Altman图比较一致性,并采用多元线性回归分析探讨两量表效用差异的影响因素;采用Kruskal-Wallis检验和t检验比较区分度;采用效应量(ES)、相对效率(RE)和ROC曲线下面积(ROC-AUC)比较灵敏度;比较天花板效应与地板效应。结果:5415个CVD高危人群中,两量表聚合效度较好,但各维度相关性较差,且测量结果一致性水平较低(ICC=0.367)。两量表对健康状况的区分度均较好,但SF-6Dv2的灵敏度更优且天花板效应更轻微。结论:在测量心血管病高危人群健康效用值时,量表选择需审慎,尤其是针对风险级别较高群体,使用SF-6Dv2更合适。 展开更多
关键词 CVD EQ-5D-5L SF-6Dv2 健康效用值
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联合竖向排水体真空预压处理软土模型试验研究
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作者 储诚富 蔡沪荣 宗文强 《合肥工业大学学报(自然科学版)》 北大核心 2025年第10期1364-1370,1377,共8页
文章针对当前软土固结排水中所用塑料排水板(prefabricated vertical drain,PVD)存在的缺陷,综合考虑工业废料尾矿砂和农作物秸秆的合理利用,提出以排水板、尾矿砂和棉花秸秆为原材料制成联合竖向排水体(combined vertical drain,CVD);... 文章针对当前软土固结排水中所用塑料排水板(prefabricated vertical drain,PVD)存在的缺陷,综合考虑工业废料尾矿砂和农作物秸秆的合理利用,提出以排水板、尾矿砂和棉花秸秆为原材料制成联合竖向排水体(combined vertical drain,CVD);通过自行设计的室内模型试验,研究CVD和普通PVD真空预压处理软土的差异性。试验结果表明:相比于PVD,使用CVD处理软土时真空度衰减平均降低37.11%,孔隙水压力消散最大值提升27.56%,排水速率最大可提高1.5倍,表层沉降增加37.02%;相比于PVD,使用CVD处理后的软土平均含水率多降低6.65%,十字板剪切强度平均值提升8.34 kPa,不同位置土体的物理性质差异更小。试验研究证明,使用CVD处理软土是可行的,具有比PVD更好的排水固结效果。 展开更多
关键词 联合竖向排水体(CVD) 排水固结法 软土 室内模型试验 废物利用
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Enhancing Heart Sound Classification with Iterative Clustering and Silhouette Analysis:An Effective Preprocessing Selective Method to Diagnose Rare and Difficult Cardiovascular Cases
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作者 Sami Alrabie Ahmed Barnawi 《Computer Modeling in Engineering & Sciences》 2025年第8期2481-2519,共39页
In the effort to enhance cardiovascular diagnostics,deep learning-based heart sound classification presents a promising solution.This research introduces a novel preprocessing method:iterative k-means clustering combi... In the effort to enhance cardiovascular diagnostics,deep learning-based heart sound classification presents a promising solution.This research introduces a novel preprocessing method:iterative k-means clustering combined with silhouette score analysis,aimed at downsampling.This approach ensures optimal cluster formation and improves data quality for deep learning models.The process involves applying k-means clustering to the dataset,calculating the average silhouette score for each cluster,and selecting the clusterwith the highest score.We evaluated this method using 10-fold cross-validation across various transfer learningmodels fromdifferent families and architectures.The evaluation was conducted on four datasets:a binary dataset,an augmented binary dataset,amulticlass dataset,and an augmentedmulticlass dataset.All datasets were derived from the Heart Wave heart sounds dataset,a novelmulticlass dataset introduced by our research group.To increase dataset sizes and improve model training,data augmentation was performed using heartbeat cycle segmentation.Our findings highlight the significant impact of the proposed preprocessing approach on the HeartWave datasets.Across all datasets,model performance improved notably with the application of our method.In augmented multiclass classification,the MobileNetV2 model showed an average weighted F1-score improvement of 27.10%.In binary classification,ResNet50 demonstrated an average accuracy improvement of 8.70%,reaching 92.40%compared to its baseline performance.These results underscore the effectiveness of clustering with silhouette score analysis as a preprocessing step,significantly enhancing model accuracy and robustness.They also emphasize the critical role of preprocessing in addressing class imbalance and advancing precision medicine in cardiovascular diagnostics. 展开更多
关键词 Heart sound MURMURS cardiovascular diseases(cvds) transfer learning convolutional neural network(CNN) deep learning K-means silhouette analysis
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Association between long-term total sleep duration and physical activity trajectories and cardiovascular diseases among middle-aged and older adults:a 9-year longitudinal study
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作者 Yan LI Ya-Ling HUANG +2 位作者 Hai-Rou SU Gui-Bing WU Zhi-Xin ZHU 《Journal of Geriatric Cardiology》 2025年第7期625-637,共13页
Background It remains unclear whether sleep duration and physical activity(PA)trajectories in middle-aged and older adults are associated with different risks of cardiovascular diseases(CVDs).This study aimed to explo... Background It remains unclear whether sleep duration and physical activity(PA)trajectories in middle-aged and older adults are associated with different risks of cardiovascular diseases(CVDs).This study aimed to explore the trajectories of total sleep duration and PA among middle-aged and older Chinese adults and their impact on CVD risk.Methods This study was based on the China Health and Retirement Longitudinal Study.12009 adults aged 45 years and older from five waves were included.CVD events were measured by self-reports of heart disease and stroke.We first used groupbased trajectory modeling to identify total sleep duration and PA trajectories from 2011 to 2020,and then employed logistic regression models to analyze their risk for CVD.Results We identified three sleep duration and PA trajectories.The risk of heart disease increased by 33%(OR=1.31,95%CI:1.12-1.53)for the short sleep duration trajectory(vs.moderate sleep duration trajectory),by 40%(OR=1.40,95%CI:1.06-1.84)for the high decreasing PA trajectory,and by 20%(OR=1.20,95%CI:1.01-1.42)for the low stable PA trajectory(vs.high stable PA trajectory),respectively.Similar results for stroke and CVD as the outcomes were also observed,but the higher risk of stroke in the high decreasing PA trajectory group was not statistically significant.The joint effects of sleep and PA showed lower risks of heart disease and stroke in trajectories with moderate or long sleep duration and high stable PA compared with short sleep duration and a low stable PA trajectory.Conclusions Short total sleep duration,high decreasing PA,and low stable PA trajectories could increase the risk of CVDs among middle-aged and older adults.Long-term moderate to long total sleep durations and high stable PA trajectories might be optimal for preventing CVDs. 展开更多
关键词 sleep duration physical activity pa trajectories cardiovascular diseases cvds cardiovascular diseases middle aged older adults events measured physical activity longitudinal study
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Global, regional, and national burden of ischemic heart disease attributable to metabolic risks: a systematic analysis of Global Burden of Disease 2021
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作者 Bo-Qing LIU Chang YANG +1 位作者 Heng-Yang WEI Zai-Xin YU 《Journal of Geriatric Cardiology》 2025年第3期361-380,共20页
Background Ischemic heart disease(IHD) represents the most significant disease burden among all cardiovascular diseases(CVDs). The increasing prevalence of metabolic risks in the 21st century has a profound impact on ... Background Ischemic heart disease(IHD) represents the most significant disease burden among all cardiovascular diseases(CVDs). The increasing prevalence of metabolic risks in the 21st century has a profound impact on the disease burden associated with IHD. We analyzed the global, regional, and national burdens of IHD attributable to metabolic risks from 1990 to 2021.Methods The data were taken from Global Burden of Disease(GBD) study 2021. Deaths, disability-adjusted life years(DALYs),the average annual percent change(AAPC), age-standardized death rates per 100,000 persons(ASDR) and age-standardized rate per 100,000 persons(ASR) of DALYs ranging from 1990 to 2021, were extracted and stratified according to region, nationality, socio-demographic index(SDI), sex, and age. Additionally, the global future trends were predicted using Nordpred prediction model.Results Compared to 1990, in 2021, the number of death and DALYs from metabolic risk-attributed IHD increased globally by67.35% and 59.91%, respectively;whereas ASDR and ASR of DALYs showed a decreasing trend and the most severe impact was observed in male and elderly populations. In addition, the burden of disease showed an inverted V-shaped relationship with SDI from 1990 to 2021. AAPC showed a significant increase in developing countries and a decrease in developed countries. We also analyzed the effects of different risk factors including metabolic risk factors on IHD in different SDI regions and genders. The prediction of future disease burden showed that the number of death and DALYs will keep rising, while ASDR and ASR of DALYs will maintain a certain downward trend.Conclusions The results of this study highlighted the need for screening and intervention for metabolic risk factors in specific regions and populations, this should call for increased collaboration between developing and developed countries to reduce the burden of disease and improve the prognosis of patients with IHD. 展开更多
关键词 BURDEN global burden cardiovascular diseases cvds global burden disease study ischemic heart disease ischemic heart disease ihd metabolic risks national burden
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静脉血栓栓塞和心血管疾病风险关联的双向孟德尔随机化研究 被引量:1
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作者 徐瑞宁 朱文娟 +2 位作者 杨颖 智宏 王莉娜 《中国循证医学杂志》 北大核心 2025年第7期783-789,共7页
目的应用两样本双向孟德尔随机化(MR)法探讨静脉血栓栓塞(VTE)和心血管疾病(CVD)风险之间的因果关联。方法从全基因组关联研究中获得与VTE和CVD相关的单核苷酸多态性数据作为工具变量。采用逆方差加权法(IVW)作为主要MR方法,其余方法作... 目的应用两样本双向孟德尔随机化(MR)法探讨静脉血栓栓塞(VTE)和心血管疾病(CVD)风险之间的因果关联。方法从全基因组关联研究中获得与VTE和CVD相关的单核苷酸多态性数据作为工具变量。采用逆方差加权法(IVW)作为主要MR方法,其余方法作为补充分析。采用Cochran’s Q检验,MR-Egger的截距项以及MR-PRESSO法评估多效性和异质性,以确保结果的稳健性。采用反向MR分析,验证是否存在反向因果关联。结果IVW方法提示VTE与房颤之间存在因果关联[OR=1.033,95%CI(1.009,1.058),P=0.008],但未发现VTE与冠心病[OR=0.994,95%CI(0.974,1.023),P=0.551]、心力衰竭[OR=1.021,95%CI(0.992,1.050),P=0.159]和心肌梗死[OR=1.012,95%CI(0.971,1.055),P=0.568]之间存在因果关系。Cochran’s Q检验结果显示,VTE和CVD的MR分析不存在异质性。MR-Egger截距分析和MR-PRESSO的全局检测均未检测到潜在的水平多效性,分析结果稳健。反向MR分析表明VTE与CVD之间不存在反向因果关联。结论MR研究结果表明VTE与房颤风险之间存在因果关联,但与冠心病、心力衰竭和心肌梗死无因果关联。 展开更多
关键词 静脉血栓栓塞 CVD 孟德尔随机化 因果关联 全基因组关联研究
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纳秒激光复合离子束刻蚀技术的CVD金刚石抛光研究
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作者 冯昱森 赵智炎 +3 位作者 于颜豪 徐颖 徐地华 李爱武 《激光杂志》 北大核心 2025年第1期214-221,共8页
高表面平整度的CVD金刚石在微刀具、光学窗口、半导体等领域具有非常广阔的应用前景。然而,由于CVD金刚石具有的高硬度、高耐磨性和化学惰性等特性,使得CVD金刚石的高精度抛光成为一个巨大的挑战。针对金刚石抛光难度问题,使用纳秒激光... 高表面平整度的CVD金刚石在微刀具、光学窗口、半导体等领域具有非常广阔的应用前景。然而,由于CVD金刚石具有的高硬度、高耐磨性和化学惰性等特性,使得CVD金刚石的高精度抛光成为一个巨大的挑战。针对金刚石抛光难度问题,使用纳秒激光复合离子束刻蚀技术抛光CVD金刚石,开展了多晶CVD金刚石激光抛光实验研究,针对激光功率和扫描速度两种激光参数研究其对CVD金刚石烧蚀深度和表面粗糙度的影响,在此基础上对激光抛光后的CVD金刚石进行离子束蚀刻抛光,研究了离子束抛光下的金刚石表面粗糙度变化,并对离子束抛光后的金刚石表面成分进行分析。通过所述方法实现了CVD金刚石样品表面粗糙度从6.687μm降到0.804μm的优异的抛光效果。此研究提供了一种旨在红外窗口、微型铣床和航天航空等领域具有应用价值的金刚石抛光方法。 展开更多
关键词 激光光学 纳秒激光抛光 离子束抛光 CVD金刚石 粗糙度
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CVD金刚石膜应力的产生、抑制、应用及测量 被引量:1
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作者 李成明 周闯 +5 位作者 刘鹏 郑礼平 赖泳机 陈良贤 刘金龙 魏俊俊 《无机材料学报》 北大核心 2025年第11期1188-1200,共13页
金刚石具有优异的性能,在光学、电子器件热管理及宽禁带半导体领域有着广阔的应用前景,被誉为终代半导体。作为光学窗口,需要大尺寸、厚度2 mm以上的CVD(Chemical Vapor Deposition,化学气相沉积)金刚石自支撑厚膜;在半导体散热中,则需... 金刚石具有优异的性能,在光学、电子器件热管理及宽禁带半导体领域有着广阔的应用前景,被誉为终代半导体。作为光学窗口,需要大尺寸、厚度2 mm以上的CVD(Chemical Vapor Deposition,化学气相沉积)金刚石自支撑厚膜;在半导体散热中,则需要4英寸(1英寸=2.54 cm)以上、100μm厚的金刚石自支撑膜与GaN等半导体材料进行键合。但由于技术限制,大面积CVD金刚石膜的合成及应用依旧存在较大困难。一方面,沉积过程中应力会导致金刚石膜发生破裂;另一方面,残余应力会导致金刚石膜发生翘曲,键合质量变差。因此,控制金刚石膜的应力成为目前金刚石膜规模化、大范围应用的一个关键问题。本文综述了CVD金刚石应力的分类、来源以及影响应力的各种因素,详细介绍了抑制金刚石膜应力的措施。同时,总结了通过人为施加应力来改善金刚石性能的研究,包括应力改变金刚石带隙、应力提高金刚石热导率等。最后,给出了评价金刚石应力大小的方法及理论计算公式,并分析了未来金刚石膜应力研究的趋势。 展开更多
关键词 CVD金刚石 膜应力 应力抑制 应力应用 应力测量 综述
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基于硅尖的垂直取向碳纳米管制备研究
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作者 汪浩宇 周宏 +2 位作者 王翊 陆仲明 李铁 《功能材料与器件学报》 2025年第6期469-476,共8页
面向原子力显微镜(atomic force microscope,AFM)探针的应用需求,提出一种基于硅尖的垂直取向碳纳米管(carbon nanotubes,CNTs)制备方法。首先,通过优化掩膜设计和KOH湿法腐蚀工艺,制备了高度约为6μm的硅尖阵列;然后,采用图案化催化剂... 面向原子力显微镜(atomic force microscope,AFM)探针的应用需求,提出一种基于硅尖的垂直取向碳纳米管(carbon nanotubes,CNTs)制备方法。首先,通过优化掩膜设计和KOH湿法腐蚀工艺,制备了高度约为6μm的硅尖阵列;然后,采用图案化催化剂定位投放技术,在硅尖顶端实现了铁蛋白分子的选择性附着;最后,通过热化学气相沉积(chemical vapor deposition,CVD)法,在优化的工艺参数下,成功在硅尖上生长出直径约16~20 nm、垂直取向的单根碳纳米管。扫描电子显微镜(scanning electron microscopy,SEM)和透射电子显微镜(transmission electron microscopy,TEM)表征结果显示,所制备的CNTs结构均匀且结晶度良好;拉曼光谱分析进一步证实其具有高度石墨化特性。研究结果可为高性能AFM探针的制备提供可行的技术方案,具有重要的应用价值。 展开更多
关键词 碳纳米管 CVD法 AFM探针 硅尖端 催化剂定位
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铜合金表面DLC涂层摩擦学特性研究
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作者 纪磊磊 喻岚 +2 位作者 唐华 于爽爽 李多生 《功能材料》 北大核心 2025年第7期7230-7236,共7页
采用磁控增强PVD/CVD复合沉积方法,在铜合金表面沉积Cr/Cr+WC/WC-DLC/DLC多层涂层,通过设计中间梯度层WC-DLC的厚度,期望提高铜合金的力学性能。采用扫描电子显微镜、拉曼光谱仪、X射线光电子能谱对DLC涂层微结构进行表征,运用纳米压痕... 采用磁控增强PVD/CVD复合沉积方法,在铜合金表面沉积Cr/Cr+WC/WC-DLC/DLC多层涂层,通过设计中间梯度层WC-DLC的厚度,期望提高铜合金的力学性能。采用扫描电子显微镜、拉曼光谱仪、X射线光电子能谱对DLC涂层微结构进行表征,运用纳米压痕仪、纳米划痕测试仪及往复干式摩擦计对其力学性能进行研究。结果表明,随着中间梯度层厚度的增加,DLC涂层的纳米压痕硬度从12.9 GPa先降低到11.4 GPa后上升到14.6 GPa。铜合金与DLC涂层的结合力达到HF-1级。这种梯度层间设计使得铜锡合金与DLC涂层结合力及硬度显著提高。稳态时摩擦系数为0.089(Si_(3)N_(4))和0.193(GCr15)。相比于铜合金基体,DLC涂层呈现优异的摩擦学性能。 展开更多
关键词 DLC 中间梯度层 摩擦磨损性能 铜合金 PVD/CVD
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VO_(2)对刀具CVD金刚石涂层热应力的调节作用研究
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作者 徐洛 杜星祝 +2 位作者 吴超逸 金坚 卢文壮 《表面技术》 北大核心 2025年第12期145-151,共7页
目的通过降低热应力的方式,解决刀具CVD金刚石涂层在切削过程中易脱落的问题。方法使用热致相变材料VO_(2)作为硬质合金刀具与CVD金刚石涂层的中间层。建立M相VO_(2)(333)晶胞模型和VO_(2)/金刚石涂层体系模型,采用分子动力学模拟的方法... 目的通过降低热应力的方式,解决刀具CVD金刚石涂层在切削过程中易脱落的问题。方法使用热致相变材料VO_(2)作为硬质合金刀具与CVD金刚石涂层的中间层。建立M相VO_(2)(333)晶胞模型和VO_(2)/金刚石涂层体系模型,采用分子动力学模拟的方法,模拟VO_(2)的相变过程并计算升温过程中涂层体系的热应力变化情况。制备了VO_(2)/CVD金刚石涂层,使用X射线应力分析仪对升温过程中的涂层应力变化进行实时测量。结果建立的VO_(2)模型在330 K附近发生相变,体系能量突变,内部原子位置发生变化。仿真结果显示,VO_(2)/金刚石界面模型热应力在323.15~373.15 K发生突变,涂层应力降低约400 MPa;试验结果显示,涂层VO_(2)在323.15~328.15 K发生突变,热应力降低约300 MPa,VO_(2)的相变温度和应力调控的试验结果与仿真结果趋势一致。结论加入VO_(2)中间层可降低CVD金刚石涂层的热应力,对提高刀具CVD金刚石涂层抗剥落能力具有重要意义。 展开更多
关键词 CVD金刚石涂层 VO_(2) 热应力 热致相变材料 调节
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交联碳纳米管基质封装硅纳米片作为高性能锂离子电池负极
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作者 曲昌宇 李佳祥 +9 位作者 何澄澄 董昱免 李治庆 王征平 苗志超 田爽 唐煌 周通 周晋 高培波 《材料导报》 北大核心 2025年第S1期27-33,共7页
硅纳米片因其独特的二维结构和高储锂特性,作为锂离子电池负极材料引起了研究人员的极大兴趣。然而,硅纳米片固有的低导电特性使得硅负极在高电流密度下的容量利用率不足,阻碍了其实际应用。鉴于此,本工作通过蛭石模板诱导硅纳米片(SiNS... 硅纳米片因其独特的二维结构和高储锂特性,作为锂离子电池负极材料引起了研究人员的极大兴趣。然而,硅纳米片固有的低导电特性使得硅负极在高电流密度下的容量利用率不足,阻碍了其实际应用。鉴于此,本工作通过蛭石模板诱导硅纳米片(SiNSs),结合镍催化的化学气相沉积,设计了一种集成硅纳米片和碳纳米管(CNT)网络的高导电复合材料。硅纳米片上生长的碳管网络有效增强了电化学反应动力学和电极结构稳定性。电化学测试结果表明,所得的SiNSs/CNT负极在100 mA/g下表现出3413.7 mAh/g的高初始容量;即使在5000 mA/g大电流密度下,其经过300次长循环仍然可以保持879.8 mAh/g的高可逆容量,展现了较高的倍率性能。此外,这项工作为制造具有高能量密度的电极提供了一条新途径。 展开更多
关键词 硅纳米片 碳纳米管(CNT) 化学气相沉积(CVD) 蛭石 锂离子电池
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