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基于分子动力学的聚丙烯电热应力老化特性分析
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作者 高煦轲 常曦文 +2 位作者 仝殿杰 王璁 屠幼萍 《电力电容器与无功补偿》 2024年第1期88-94,共7页
高压直流输电(HVDC)工程中广泛应用的聚丙烯(PP)薄膜电容器,其内部高温和高场强是PP老化的主要原因。基于分子动力学仿真方法,从分子层面研究了PP在电热应力下的老化过程。首先建立PP和含羰基PP分子模型,基于反应力场分别模拟了热、电... 高压直流输电(HVDC)工程中广泛应用的聚丙烯(PP)薄膜电容器,其内部高温和高场强是PP老化的主要原因。基于分子动力学仿真方法,从分子层面研究了PP在电热应力下的老化过程。首先建立PP和含羰基PP分子模型,基于反应力场分别模拟了热、电应力作用下PP裂解反应,分析了主要产物形成过程;然后基于COMPASS力场分析热应力下PP力学和绝缘性能变化规律。结果表明:PP裂解反应中C—H键首先断裂,然后是C—C键的断裂并形成羰基,在此过程中热应力对于PP的电热老化影响更显著;温度在450 K以下时,PP力学参数基本不变,当温度达到600 K时,PP力学参数显著变化,稳定性下降;羰基影响PP老化过程中的力学和绝缘性能变化,含羰基PP能隙下降28.21%,在300 K、450 K和600 K时弹性模量分别增加15.3%,32.85%和27.08%。 展开更多
关键词 聚丙烯 绝缘性能 分子动力学 COMPASS力场 反应力场 老化
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Dynamic ultrasonography for optimizing treatment position in superior mesenteric artery syndrome:Two case reports and review of literature
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作者 Nobuaki Hasegawa Akihiko Oka +4 位作者 Muyiwa Awoniyi Yuri Yoshida Hiroshi Tobita Norihisa Ishimura Shunji Ishihara 《World Journal of Gastroenterology》 SCIE CAS 2024年第5期499-508,共10页
BACKGROUND Superior mesenteric artery(SMA)syndrome is a rare cause of duodenal obstruction by extrinsic compression between the SMA and the aorta(SMA-Ao).Although the left lateral recumbent position is considered effe... BACKGROUND Superior mesenteric artery(SMA)syndrome is a rare cause of duodenal obstruction by extrinsic compression between the SMA and the aorta(SMA-Ao).Although the left lateral recumbent position is considered effective in the treatment of SMA syndrome,individual variations in the optimal patient position have been noted.In this report,we present two elderly cases of SMA syndrome that exhibited rapid recovery due to ultrasonographic dynamic evaluation of the optimal position for each patient.CASE SUMMARY Case 1:A 90-year-old man with nausea and vomiting.Following diagnosis of SMA syndrome by computed tomography(CT),ultrasonography(US)revealed the SMA-Ao distance in the supine position(4 mm),which slightly improved in the lateral position(5.7–7.0 mm)without the passage of duodenal contents.However,in the sitting position,the SMA-Ao distance was increased to 15 mm accompanied by improved content passage.Additionally,US indicated enhanced passage upon abdominal massage on the right side.By day 2,the patient could eat comfortably with the optimal position and massage.Case 2:An 87-year-old woman with vomiting.After the diagnosis of SMA syndrome and aspiration pneumonia by CT,dynamic US confirmed the optimal position(SMA-Ao distance was improved to 7 mm in forward-bent position,whereas it remained at 5 mm in the supine position).By day 7 when her pneumonia recovered,she could eat with the optimal position.CONCLUSION The optimal position for SMA syndrome varies among individuals.Dynamic US appears to be a valuable tool in improving patient outcomes. 展开更多
关键词 Superior mesenteric artery syndrome Wilkie’s syndrome Cast syndrome Aorto-mesenteric compass syndrome ULTRASONOGRAPHY Case report
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Modern Ideas of Caring in Nursing Practices
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作者 Ukasha Hameed 《Journal of Clinical and Nursing Research》 2024年第6期247-255,共9页
For effective nursing practice,it is essential to have a strong foundation in ethical principles and a shared understanding of nursing and caring concepts.Emphasizing compassion in nursing is crucial.This study aimed ... For effective nursing practice,it is essential to have a strong foundation in ethical principles and a shared understanding of nursing and caring concepts.Emphasizing compassion in nursing is crucial.This study aimed to elucidate the core ideals of compassion,ethics,and care in nursing practice.Nurses can foster a deeper sense of personal significance in their caregiving relationships by demonstrating attentiveness,openness,and respect and treating each patient as an individual.Through self-reflection,nurses can develop a greater understanding of nursing,compassion,and ethical principles within the caregiving context.This reflective practice enables nurses to connect more profoundly with their patients,enhancing the quality of care.By integrating these core ideals into their practice,nurses not only improve patient outcomes but also find greater personal fulfilment in their professional roles.Thus,cultivating compassion and ethical awareness is fundamental to the holistic and effective practice of nursing. 展开更多
关键词 NURSING PATIENTS Ethical principles CAREGIVING COMPASSION
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使用Compass验证系统对脑瘤VMAT计划的三维剂量学进行定量评估
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作者 邱凌平 阙与清 +3 位作者 李克 殷皓泽 张婷 李勇 《中国医药指南》 2023年第31期57-59,共3页
目的使用带有Dolphin探测器的Compass验证系统对脑瘤VMAT计划进行三维剂量验证,从而保证脑瘤放疗的剂量准确性以及临床更佳的剂量验证方案。方法选取20例在我院接受放射治疗的脑瘤患者,基于3%/2 mm评估标准,利用Compass独立计算和Dolphi... 目的使用带有Dolphin探测器的Compass验证系统对脑瘤VMAT计划进行三维剂量验证,从而保证脑瘤放疗的剂量准确性以及临床更佳的剂量验证方案。方法选取20例在我院接受放射治疗的脑瘤患者,基于3%/2 mm评估标准,利用Compass独立计算和Dolphin实测重建结果比较靶区和危及器官的γ通过率。结果Compass独立计算结果显示,靶区γ通过率平均为94.92%、94.43%,危及器官γ通过率均在92%以上;Dolphin实测重建结果显示,靶区γ通过率平均为97.12%、96.67%,危及器官γ通过率则在93%以上。经证实二者均符合临床标准,但Dolphin实测重建结果优于Compass独立计算。结论在对脑瘤患者进行剂量验证时,尽管重建剂量结果优于独立计算结果,但是二者差异较小,基于三维剂量重建过程更加繁琐、耗时,临床上无法适用于所有患者,建议针对独立计算通过率较低的患者再进行实测,这样既能保证剂量准确性,又能减轻临床工作压力。 展开更多
关键词 脑肿瘤 剂量验证 Compass验证系统 Dolphin探测器
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Superior mesenteric artery syndrome:Diagnosis and management 被引量:3
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作者 Akihiko Oka Muyiwa Awoniyi +4 位作者 Nobuaki Hasegawa Yuri Yoshida Hiroshi Tobita Norihisa Ishimura Shunji Ishihara 《World Journal of Clinical Cases》 SCIE 2023年第15期3369-3384,共16页
Superior mesenteric artery(SMA)syndrome(also known as Wilkie's syndrome,cast syndrome,or aorto-mesenteric compass syndrome)is an obstruction of the duodenum caused by extrinsic compression between the SMA and the ... Superior mesenteric artery(SMA)syndrome(also known as Wilkie's syndrome,cast syndrome,or aorto-mesenteric compass syndrome)is an obstruction of the duodenum caused by extrinsic compression between the SMA and the aorta.The median age of patients is 23 years old(range 0-91 years old)and predominant in females over males with a ratio of 3:2.The symptoms are variable,consisting of postprandial abdominal pain,nausea and vomiting,early satiety,anorexia,and weight loss and can mimic anorexia nervosa or functional dyspepsia.Because recurrent vomiting leads to aspiration pneumonia or respiratory depression via metabolic alkalosis,early diagnosis is required.The useful diagnostic modalities are computed tomography as a standard tool and ultrasonography,which has advantages in safety and capability of real-time assessments of SMA mobility and duodenum passage.The initial treatment is usually conservative,including postural change,gastroduodenal decompression,and nutrient management(success rates:70%-80%).If conservative therapy fails,surgical treatment(i.e.,laparoscopic duodenojejunostomy)is recommended(success rates:80%-100%). 展开更多
关键词 Superior mesenteric artery syndrome Wilkie’s syndrome Cast syndrome Aorto-mesenteric compass syndrome
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Digital compass for multi-user beam access in mmWave cellular networks
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作者 Adel Aldalbahi Nazli Siasi +1 位作者 Asim Mazin Mohammed A.Jasim 《Digital Communications and Networks》 SCIE CSCD 2023年第4期879-886,共8页
Beamforming in stand-alone Millimeter-Wave(mmWave)communications results in prolonged access times and latencies due to the increased number of measurements required to determine the optimal beam directions at the Mob... Beamforming in stand-alone Millimeter-Wave(mmWave)communications results in prolonged access times and latencies due to the increased number of measurements required to determine the optimal beam directions at the Mobile Station(MS)and Base Station(BS),returning the highest received signal level.Therefore,dynamic and fast access schemes that meet the Third-Generation Partnership Project(3GPP)specifications are required here.Therefore,in this paper,a novel initial access scheme is proposed for multiple MS users by leveraging for the first time a digital compass in the access procedure.Namely,when a new MS joins the footprint of a BS,it probes the channel for beacon signaling about the BS direction,i.e.,broadcasted by a neighboring MS that completed beam association at previous time steps.Then,a digital compass is utilized to adjust the coordinates of the BS according to the location of the new MS.The proposed scheme is applied for a single and multi-user settings at various broadcasting approaches.This includes a single associated MS user that broadcasts information to a single incoming MS user,a single user that broadcasts signals to multiple incoming users,or all multiple associated users broadcast to multiple incoming users.Overall,the proposed schemes yield in notable efficiency in terms of the computational complexity,access times,power and energy consumption as compared to existing access schemes.Further,high success rates are achieved at the detriment of relatively higher cost. 展开更多
关键词 Millimeter wave Initial beam access Electronic compass BEAMFORMING Access times Energy consumption
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Prevalence and Social Demographic Factors Associated with Secondary Traumatic Stress, Burnout and Compassion Satisfaction among Nurses at Selected Teaching Hospitals in Lusaka, Zambia
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作者 Michael Mumba Kanyanta Marjorie Kabinga Makukula Ruth Wahila 《Journal of Biosciences and Medicines》 CAS 2023年第2期86-104,共19页
Introduction: Nurses’ constant exposure to severe human suffering within constrained health care environments places them at risk for developing Secondary Traumatic Stress and Burnout. The current study therefore sou... Introduction: Nurses’ constant exposure to severe human suffering within constrained health care environments places them at risk for developing Secondary Traumatic Stress and Burnout. The current study therefore sought to establish the prevalence and social demographic factors associated with Secondary Traumatic Stress, Burnout and Compassion Satisfaction among Nurses working at selected Teaching Hospitals in Lusaka, Zambia. Methods: A correlational design employing a self-administered questionnaire adapted from version five of the Professional Quality of Life scale was used to collect data from 250 nurses drawn using proportional stratified sampling method. The resulting data were analyzed using version 23 of the Statistical Package for Social Sciences (SPSS). Hierarchical multiple linear regression analysis was used to identify predictors of Secondary Traumatic Stress and Burnout. Findings: Whilst the majority of respondents reported average levels of Secondary Traumatic Stress and Burnout, about a quarter reported high Secondary Traumatic Stress and Burnout scores at 23% and 26% respectively. Only 81 (32.4%) scored high on Compassion Satisfaction. Social demographic factors including;working in the main Intensive Care Unit, and being married accounted for the greatest variance in Secondary Traumatic Stress (R<sup>2</sup> = 0.237, p Conclusion: Findings of the current study signify a need to institute measures to help nurses cope with the deleterious psychological effects of constant engagement with those in distress and to foster Compassion Satisfaction. 展开更多
关键词 Secondary Traumatic Stress BURNOUT Compassion Satisfaction Compassion Fatigue NURSE
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Comparative study of self-compassion and sense of coherence in nurses of psychiatric hospitals
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作者 Iman Nosratabadi Golnaz Forough Ameri +1 位作者 Sedigheh Iranmanesh Neda Asadi 《Frontiers of Nursing》 2023年第2期193-201,共9页
Objective:Nurses,due to the nature of their job,are subjected to various forms of stress and physical and psychological injuries.Self-compassion and a sense of coherence have attracted much attention in research in re... Objective:Nurses,due to the nature of their job,are subjected to various forms of stress and physical and psychological injuries.Self-compassion and a sense of coherence have attracted much attention in research in recent years as having high potential for improving the health and performance of people in the workplace.The present study aimed to compare self-compassion and the sense of coherence in nurses working in psychiatric hospitals and other hospitals of Kerman University of Medical Sciences.Methods:The present study was a descriptive-comparative study of applied type conducted on 100 nurses of Shahid Beheshti Psychiatric Hospital in Kerman by the census method and 100 nurses of other hospitals of Kerman University of Medical Sciences by the stratified random sampling method.The instruments included the self-compassion questionnaire and the sense of coherence questionnaire.Data were analyzed using the Statistical Package for Social Sciences software.Results:The results of the present study showed that self-compassion and sense of coherence were higher in psychiatric nurses(39.35±7.7 and 53.02±8.01)than among other nurses(36.03±5.81 and 49.76±6.30).There was a direct and moderate relationship between a sense of coherence and self-compassion(P-value<0.005).The higher the score of compassion for oneself,the higher was the score of sense of coherence.Furthermore,the sense of coherence had a direct and weak relationship with all dimensions of self-compassion,except for the extreme imitation dimension,which showed a direct and moderate relationship to other dimensions(P-value<0.001).Conclusions:Self-compassion and a sense of coherence,as a form of self-communication,increase nurses’satisfaction and reduce nurses’job stress and,as a result,job performance is improved. 展开更多
关键词 nurses psychiatric hospital SELF-COMPASSION sense of coherence COMPASSION COHERENCE
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某半潜船叠船系统下潜作业过程中的稳性研究
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作者 王辉 吕成飞 +2 位作者 王秀娟 张玉明 李志勇 《船舶与海洋工程》 2023年第1期1-5,12,共6页
以某60 000载重吨半潜船为例,利用中国船级社开发的稳性计算软件Compass对其在载货下潜作业过程中的初稳性进行研究。针对半潜船搭载双驳船和海洋平台模块形成的"叠船系统",建立把双驳船和平台的重量看作外载荷与计入双驳船... 以某60 000载重吨半潜船为例,利用中国船级社开发的稳性计算软件Compass对其在载货下潜作业过程中的初稳性进行研究。针对半潜船搭载双驳船和海洋平台模块形成的"叠船系统",建立把双驳船和平台的重量看作外载荷与计入双驳船的浮力对稳性的贡献2种计算模型,对稳心到基线高度、横稳心高等稳性参数随吃水的变化规律进行研究。结果表明,计入双驳船的浮力对稳性的贡献可有效改善半潜船在下潜作业过程中稳性不足的危险。研究结果可供半潜船运输大型海洋模块新模式的安全评估参考。 展开更多
关键词 半潜船 作业稳性 叠船模型 Compass软件
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Measurement of cervical range of motion using smartphone compass in the healthy people:a cross-sectional pilot study
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作者 Jun-Qing Zhong Xi Zhao +2 位作者 Jing-Yao Wang Dan Meng Ze-Yu Zhong 《TMR Non-Drug Therapy》 2023年第1期1-7,共7页
Objective:This study evaluates the reliability of smartphone compass software in measuring the cervical range of motion in healthy people.Methods:We selected 40 healthy intern college students from Tianjin Hospital fr... Objective:This study evaluates the reliability of smartphone compass software in measuring the cervical range of motion in healthy people.Methods:We selected 40 healthy intern college students from Tianjin Hospital from June to August 2022 to participate in this study.Two physiotherapists used a smartphone(iPhone 11256 Gb(model A2223))compass software to measure six directions of motion of the cervical spine in 40 subjects in a total of 3 rounds each.The intraclass correlation coefficient was used to compare the reliability intra-group,and the Pearson correlation coefficient was also used to compare the correlation between groups,with P<0.05 being statistically significant.Results:The intraclass correlation coefficient showed good reliability(>0.5)in cervical range of motion(CROM),especially in cervical flexion and right rotation(>0.9).In the correlation comparison between the two groups,the Spearman comparison was used,and the six directions of the cervical spine were significantly correlated(P<0.05).Conclusion:The built-in compass software in smartphones has good reliability in measuring CROM in healthy people. 展开更多
关键词 cervical range of motion SMARTPHONE COMPASS intraclass correlation coefficient
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新加坡“家校社”三位一体家庭教育联动机制研究
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作者 杨素萍 《广西教育》 2023年第1期10-13,共4页
本文从“三位一体家庭教育联动的理念”“三位一体教育联动机制的构建”两个方面论述新加坡如何构建家庭、学校、社会三位一体家庭教育联动机制,并从树立责任意识、合理整合资源、结合具体国情等方面,探讨新加坡COMPASS式家庭教育联动... 本文从“三位一体家庭教育联动的理念”“三位一体教育联动机制的构建”两个方面论述新加坡如何构建家庭、学校、社会三位一体家庭教育联动机制,并从树立责任意识、合理整合资源、结合具体国情等方面,探讨新加坡COMPASS式家庭教育联动机制对我国教育的启示。 展开更多
关键词 新加坡 COMPASS 家庭教育
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A Study on the Quality of Life of Elderly Nurses in Two Selected Elderly Care Institutions in Shandong Province
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作者 Qing Ji 《Journal of Clinical and Nursing Research》 2023年第4期89-93,共5页
Objective: To comprehensively understand the impact of the quality of life of elderly nurses in two selected elderly care institutions in Zibo city, Shandong province, and to provide a scientific basis for improving t... Objective: To comprehensively understand the impact of the quality of life of elderly nurses in two selected elderly care institutions in Zibo city, Shandong province, and to provide a scientific basis for improving the professional quality of life of elderly nurses. Methods: The convenient sampling method was used to investigate the professional quality of life (proQOL) questionnaire Version 5 and the self-designed demographic data of 82 elderly nurses working in two elderly care institutions. Result: From this score, it can be seen that the occupational burnout problem of elderly nursing staff in the two nursing homes is the most significant, with empathy and secondary trauma emergency at a moderate level. After controlling the demographic variables, the working hours and monthly income level had a significant impact on nurses’ job burnout. Conclusion: Due to the particularity and high intensity of elderly nurses’ work, their physical and mental health faces many challenges, which affect their quality of life. At present, efforts will be made to reduce work pressure, increase wages and benefits, and thereby improve the quality of life. 展开更多
关键词 Elderly care institutions nurses Quality of life Compassion fatigue BURNOUT
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中国船级社新一代船体结构描述性规范要求评估软件COMPASS-SDP V2.0正式发布
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《中国船检》 2023年第10期10-10,共1页
2023年10月12日,中国船级社(CCS)新一代船体结构描述性规范要求评估软件COMPASS-SDP发布V2.0版本。COMPASS-SDP是CCS自主研发的新一代船体结构描述性规范要求评估软件,标志着CCS在船舶工程计算软件技术创新方面迈出了重要一步。该软件... 2023年10月12日,中国船级社(CCS)新一代船体结构描述性规范要求评估软件COMPASS-SDP发布V2.0版本。COMPASS-SDP是CCS自主研发的新一代船体结构描述性规范要求评估软件,标志着CCS在船舶工程计算软件技术创新方面迈出了重要一步。该软件的二维建模平台采用了图形交互与参数化相结合的创新模式,极大地简化了船舶二维结构模型的创建流程,显著提高了建模效率和软件友好性。软件的自动理想化及检查功能,多剖面、一键式规范评估功能以及多样化的结果分析手段,全方位提升了计算分析能力和效率,为用户提供了高效的工作体验。 展开更多
关键词 评估软件 检查功能 图形交互 中国船级社 友好性 船体结构 二维建模 COMPASS
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ICU护士同情心疲乏对其职业认同的影响 被引量:38
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作者 张慧 许翠萍 +3 位作者 薛秀娟 程彦伶 高青 郑培培 《中国护理管理》 CSCD 2014年第3期246-249,共4页
目的:探讨重症监护室(ICU)护士同情心疲乏对其职业认同的影响。方法:对山东省6家三级甲等综合医院的193名ICU护士进行问卷调查,了解ICU护士同情心疲乏及其职业认同现状,并探讨两者的关系。结果 :同情心疲乏中同情心满足和继发性创伤应... 目的:探讨重症监护室(ICU)护士同情心疲乏对其职业认同的影响。方法:对山东省6家三级甲等综合医院的193名ICU护士进行问卷调查,了解ICU护士同情心疲乏及其职业认同现状,并探讨两者的关系。结果 :同情心疲乏中同情心满足和继发性创伤应激与职业认同呈正相关(P<0.05),与工作倦怠呈负相关(P<0.01)。职业认同总分为(98.29±16.20)分。分层回归分析显示,控制人口学变量后,继发性创伤应激、同情心满足和工作倦怠可独立预测职业认同的31.9%。结论:护理管理者应提高护士的工作满意度,缓解其同情心疲乏,从而提高护士职业认同,促进护理事业的发展。 展开更多
关键词 ICU nurses COMPASSION FATIGUE PROFESSIONAL IDENTITY
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基于COMPASS-G2的地基增强系统构建与测评 被引量:5
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作者 明朝辉 韩松臣 +1 位作者 何运成 张明 《桂林理工大学学报》 CAS 北大核心 2011年第4期610-614,共5页
中国民用航空局(CAAC)实施基于性能的导航(PBN)的关键技术是北斗(COMPASS-G2)及其地基增强系统(GBAS)。本文阐述了GBAS的组成和工作流程,构建了基于COMPASS的GBAS仿真系统,给出设计方案和开发程序图。通过静止测试、机场跑道跑车试验和... 中国民用航空局(CAAC)实施基于性能的导航(PBN)的关键技术是北斗(COMPASS-G2)及其地基增强系统(GBAS)。本文阐述了GBAS的组成和工作流程,构建了基于COMPASS的GBAS仿真系统,给出设计方案和开发程序图。通过静止测试、机场跑道跑车试验和机场区域跑车测试3种方法,分析所采集数据,验证信号增强的效果。在GBAS改善信号精度的基础上,建构用于终端区指导飞行器精密进近(GLS)的北斗着陆系统性能评估体系。给出了评估北斗系统指导进近性能的地面和空中检验方法。 展开更多
关键词 PBN COMPASS GBAS 实验系统 完好性
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分子动力学模拟浓度和温度对TATB/PCTFEPBX力学性能的影响 被引量:15
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作者 马秀芳 肖继军 +3 位作者 黄辉 朱伟 李金山 肖鹤鸣 《化学学报》 SCIE CAS CSCD 北大核心 2005年第22期2037-2041,共5页
为探讨高聚物粘结炸药(Polymer Bonded Explosive,PBX)的力学性能随温度和高聚物浓度而变化的规律,用分子动力学(MD)方法和compass力场,对著名高能炸药1,3,5-三氨基-2,4,6-三硝基苯(TATB)与常用高聚物粘结剂聚三氟氯乙烯(PCTFE)所构成的... 为探讨高聚物粘结炸药(Polymer Bonded Explosive,PBX)的力学性能随温度和高聚物浓度而变化的规律,用分子动力学(MD)方法和compass力场,对著名高能炸药1,3,5-三氨基-2,4,6-三硝基苯(TATB)与常用高聚物粘结剂聚三氟氯乙烯(PCTFE)所构成的TATB/PCTFE PBX进行模拟计算.结果表明,在一定范围内,随高聚物浓度的增加,PBX的弹性系数和模量减小,表明其刚性减小、弹性增加;而随温度的升高,PBX的刚性减小、弹性增强.还发现PBX的结合能随浓度增高而增大,随温度升高而减小. 展开更多
关键词 高聚物粘结炸药(PBX) 分子动力学(MD) 力学性能 结合能 温度 粘结剂浓度 分子动力学模拟 浓度增高 温度升高 力学性能 PBX 高聚物粘结炸药 compass 聚三氟氯乙烯 高能炸药
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化学镀锡中光亮剂PPS、咪唑和HD在Sn表面的吸附作用实验与模拟研究 被引量:4
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作者 肖忠良 曾鹏 +8 位作者 周朝花 夏妮 刘青 池振振 吴道新 宋刘斌 曹忠 黄勇 周光华 《表面技术》 EI CAS CSCD 北大核心 2018年第12期270-276,共7页
目的研究以丙烷磺酸吡啶嗡盐(PPS)、咪唑、己炔二醇(HD)为代表的三大类光亮剂,在化学镀锡过程中改善镀锡层表观形貌和影响镀速的作用机理。方法采用电化学阴极极化法,研究化学镀锡过程中光亮剂分子对镀锡液在沉锡过程中对沉锡峰电位变... 目的研究以丙烷磺酸吡啶嗡盐(PPS)、咪唑、己炔二醇(HD)为代表的三大类光亮剂,在化学镀锡过程中改善镀锡层表观形貌和影响镀速的作用机理。方法采用电化学阴极极化法,研究化学镀锡过程中光亮剂分子对镀锡液在沉锡过程中对沉锡峰电位变化的影响,运用Forcite模块中的COMPASS力场进行分子动力学计算,研究光亮剂分子在Sn层表面吸附过程的能量变化。结果阴极极化结果表明,光亮剂的加入会使沉锡峰电位负移,该过电位导致晶核水平增长速度大于垂直生长速度,从而起到整平作用,并在一定程度上抑制晶须的形成。分子动力学计算结果显示,PPS、咪唑、HD均有自发吸附到Sn层表面的趋势,且在Sn(111)面的吸附能分别为-445.338、-9.84、-22.651kcal/mol,表明三种光亮剂分子均易吸附在Sn层表面(吸附能数据越低,越容易吸附在锡层表面),从而在一定程度上抑制锡层的增长。结论光亮剂与Sn作用的吸附能,与其在化学镀过程中对Sn层表观形貌的改善和镀速减少有正相关作用。该研究为化学镀锡过程中光亮剂的选择提供了理论基础。 展开更多
关键词 化学镀锡 吸附 光亮剂 分子动力学 COMPASS力场 吸附能
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Compass在直肠癌术前调强放射治疗三维剂量验证中的应用 被引量:8
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作者 段隆焱 蔡钢 +2 位作者 陈毅 张毅斌 沈文同 《中国医学物理学杂志》 CSCD 2017年第12期1200-1205,共6页
目的:探讨Compass系统在直肠癌术前调强放射治疗三维剂量验证中的临床应用。方法:选取10例直肠癌术前放疗患者在Pinnacle 9.10中进行优化设计,照射野采用七野扇形分布,利用Compass提供的剂量计算(CDD)和剂量重建(RDD)两种方法验证临床靶... 目的:探讨Compass系统在直肠癌术前调强放射治疗三维剂量验证中的临床应用。方法:选取10例直肠癌术前放疗患者在Pinnacle 9.10中进行优化设计,照射野采用七野扇形分布,利用Compass提供的剂量计算(CDD)和剂量重建(RDD)两种方法验证临床靶区(PTV)及危及器官的体积γ通过率、D_(95%)、D_(50%)、D_(2%)、D_(mean)等参数。结果:γ通过率:靶区与危及器官CDD-TPS均大于98.5%,且CDD-TPS均高于RDD-TPS。PTV和膀胱γ通过率差异显著(t=-2.731、2.298,P<0.05)。剂量体积差异:PTV的D2%、膀胱和右侧股骨头的Dmean剂量差异显著(t=-4.280、-2.582、-2.582,P<0.05)。同时PTV的D_(50%)、D_(2%)、左右侧股骨头的D_(mean)剂量差异CDD-TPS更大。结论:Compass系统提供的剂量验证方法和三维剂量偏差以及γ通过率等剂量评估指标,能够科学合理评估直肠癌术前调强放射治疗计划,具有重要的临床意义。 展开更多
关键词 直肠癌 Compass系统 调强放射治疗 剂量验证 术前放疗
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COMPASS三维验证系统在食管癌容积旋转调强放疗中的应用 被引量:4
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作者 王晓敏 唐广 +3 位作者 顾浩 赵一电 王海洋 樊锐太 《肿瘤防治研究》 CAS CSCD 2018年第11期890-893,共4页
目的探讨COMPASS三维验证系统在食管癌容积旋转调强剂量验证中的可行性。方法选取37例食管癌初治患者在Oncentra计划系统上进行容积旋转调强(VMAT)计划设计,然后将治疗计划传送至COMPASS验证系统和加速器上。比较计划系统中的计算结果和... 目的探讨COMPASS三维验证系统在食管癌容积旋转调强剂量验证中的可行性。方法选取37例食管癌初治患者在Oncentra计划系统上进行容积旋转调强(VMAT)计划设计,然后将治疗计划传送至COMPASS验证系统和加速器上。比较计划系统中的计算结果和COMPASS验证系统中实际测量结果之间的差异。分析靶区的平均剂量(Dmean)、95%体积受照射的剂量(D95)和γ值,危及器官比较双肺V20、V30剂量值。结果计算结果和测量结果在靶区上的γ通过率均>92%,靶区D95的平均值偏差<3%,Dmean标准偏差平均值<1%。测量结果与计划结果中双肺V20、V30分别为(19.86±2.18)%、(20.03±2.21)%和(12.35±2.61)%、12.40±2.52)%,明显看出测量的结果V20、V30比计算结果小。结论COMPASS三维验证系统能准确快速的分析出结果,保证食管癌治疗的安全。 展开更多
关键词 COMPASS三维验证系统 食管癌 容积旋转调强 剂量验证
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COMPASS伪距单点定位精度分析 被引量:10
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作者 李林红 何秀凤 张化疑 《大地测量与地球动力学》 CSCD 北大核心 2013年第2期58-62,共5页
通过实测COMPASS数据处理,分析COMPASS伪距观测值精度与卫星高度角的关系,以及当前4GEO+5IGSO导航星座COMPASS伪距单点定位的精度。结果表明,COMPASS伪距多路径效应和观测噪声在0~3 m之间变化,其精度为0.3~0.7 m;卫星高度角越大,多路... 通过实测COMPASS数据处理,分析COMPASS伪距观测值精度与卫星高度角的关系,以及当前4GEO+5IGSO导航星座COMPASS伪距单点定位的精度。结果表明,COMPASS伪距多路径效应和观测噪声在0~3 m之间变化,其精度为0.3~0.7 m;卫星高度角越大,多路径效应和观测噪声越小;GEO卫星受到的多路径效应和观测噪声要明显小于IGSO卫星;COMPASS伪距单点定位精度(RMS)在N、E、U方向上分别为3.33、3.45、8.84m。 展开更多
关键词 COMPASS 伪距观测量 伪距质量 伪距单点定位 卫星高度角
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