检索结果-南通市图书馆

Penumbral imaging and numerical evaluation of large area source neutron imaging system

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2009年第9期52卷 2567-2575页

作者： yuelei wu HuaSi Hu BoPing Zhang LinBo Li Da Chen Qing Shan Jie Zhu School of Nuclear Science & Technology Xi’an Jiaotong University Xi’an 710049 China Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900 China College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Xi’an Research Institute of Hi-Tech Xi’an 710025 China

The fusion neutron penumbral imaging system Monte Carlo model was established. The transfer functions of the two discrete units in the neutron source were obtained in two situations: Imaging in geometrical near-optical and real situation. The spatial resolutions of the imaging system in two situations were evaluated and compared. The penumbral images of four units in the source were obtained by means of 2-dimensional (2D) convolution and Monte Carlo simulation. The penumbral images were reconstructed with the same method of filter. The same results were confirmed. The encoding essence of penumbral imaging was revealed. With MCNP(Monte Carlo N-particle) simulation, the neutron penumbral images of the large area source (200 μm×200 μm) on scintillation fiber array were obtained. The improved Wiener filter method was used to reconstruct the penumbral image and the source image was obtained. The results agree with the preset neutron source image. The feasibility of the neutron imaging system was verified.

关键词： penumbral imaging reconstruction unit source spatial invariance spatial resolution MCNP code

Optimal design of coded aperture used for Z-Pinch driven fusion neutron imaging

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第7期58卷 1289-1293页

作者： JIA QingGang HU HuaSi ZHENG XiangYang ZHANG FengNa WANG DongMing HU Guang ZHANG TianKui wu yuelei Institute of Nuclear Science and Technology Xi'an Jiaotong University State Environmental Protection Administration (SEPA) Nuclear and Radiation Safety Centre Research Center of Laser Fusion China Academy of Engineering Physics

Currently,the neutron yield of Z-Pinch is lower than that of laser driven *** the neutron imaging for this facility,the signal to noise ratio(SNR)has a significant influence on the expected spatial resolution of the reconstructed fusion core,especially in the condition of low neutron *** this paper,mathematical model is purposed to describe the dependence of aperture parameters on the imaging *** investigation shows that the imaging SNR is closely related to the size of contrast boundary on the point spread *** to this,a novel non-uniform redundancy penumbra apertures array is *** addition,the imaging performances of this novel coded aperture,penumbra aperture and ring aperture are evaluated and compared by Monte Carlo *** comparison shows that this novel aperture has significant advantage compared to the penumbra aperture which is commonly used for neutron imaging with low *** encouraging results can provide reference for the optimal design of the coded aperture used in the neutron imaging for Z-pinch driven fusion with low neutron yield.

关键词： Z-pinch driven fusion neutron imaging coded aperture signal to noise ratio low neutron yield

Monte-Carlo simulation of pinhole collimator of a small field of view gamma camera for small animal imaging

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2009年第1期20卷 37-41页

作者： ZHU Jie MA Wenyan ZHU Yufeng MA Hongguang wu yuelei HU Huasi ZHANG Boping HUO Yonggang LIU Silu JIAN Bin WANG Zhaomin The Second Artillery Engineering College Xi＇an 710025 China Nuclear Engineering Department School of Energy ＆ Engineering Xi＇an Jiaotong University Xi＇an 710049 China Department of Modern Physics University of Science and Technology of China Hefei 230026 China Department of Electric Information Engineering Wuhan Polytechnic University Wuhan 430023 China

Needs in scintimammography applications,especially for small animal cardiac imaging,lead to develop a small field of view,high spatial resolution gamma camera with a pinhole *** the ideal pinhole collimator must keep a compromise between spatial resolution and *** order to design a pinhole collimator with an optimized sensitivity and spatial resolution,the spatial resolution and the geometric sensitivity response as a function of the source to collimator distance has been obtained by means of Monte-Carlo simulation for a small field of view gamma camera with a pinhole collimator of various-hole *** results show that the camera with pinhole of 1 mm,1.5 mm and 2 mm diameter has respectively spatial resolution of 1.5 mm,2.25 mm and 3 mm and geometric sensitivity of 0.016%,0.022%and 0.036%,while the source to collimator distance is 3 *** chose the pinhole collimator with hole diameter size of 1.2 mm for our the gamma camera designed based on the trade-off between sensitivity and resolution.

关键词：氢硼聚变衰变原子核模拟能谱

A Preliminary Study on SSR Molecular Markers of White Character of Capsicum

在线全文

学校读者我要写书评

暂无评论

Agricultural Biotechnology 2018年第3期7卷 72-74页

作者： Yijia KE Tongguang LIU Haikun JIANG Peng CHEN Xia WANG Fanru ZHOU yuelei wu Ling FANG Qian ZHANG College of Horticulture Anhui Agricultural University Horticultural Research Institute Anhui Academy of Agricultural Sciences

In this study,Paprika 247 with milk white fruit at marketable maturity stage as male parent and capsicum 246 with green fruit at marketable maturity stage as female parent were selected as experimental materials to screen SSR molecular markers closely related to white fruit character,so as to lay a foundation for the use of SSR technique for molecular marker-assisted breeding and provide reference for breeding of new white capsicum germplasms and varieties. 360 pairs of SSR primers were screened in total,and among them,3 pairs of primers（ ES-89,ES-292,ES-296） exhibited remarkable polymorphic differences. This study will provide a basis for next QTL mapping.

关键词： Capsicum White character SSR analysis

Epidemiology of community pre-hypertensive patients and related risk factors in Chengdu city

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Family Medicine and Community Health 2013年第3期1卷 27-32页

作者： Xinyun Chen Yafei Yan Fang Qin Xiaojing Jiang Bo Yu Fang Shang Jian Liu yuelei wu Dan Tang Yuanyuan Yao Tingjie Zhang Key Laboratory of Hypertension and Related Diseases First People’s Hospital of ChengduChengduChina610041 Shiyang Community Health Center ChengduChina610000 Dong Sheng Community Health Center ChengduChina610041 Qinglong Community Health Center ChengduChina610000

Objective:This study aims to explore the epidemiologic characteristics of pre-hypertension,its related risk factors of cardiovascular diseases and its relativity with metabolic disorders among community residents of Chengdu ***:Cluster random sampling was performed in three districts and counties of Chengdu.A total of 3524 residents(resident for≥1 year,≥18 years of age)were enrolled in the *** the participants were interviewed in the questionnaire *** examination,blood pressure measurements,and blood sampling were also ***:The overall prevalence of pre-hypertension was 34.07%.The prevalence of prehyper-tension was higher in males than in females(41.16%vs.23.89%,P<0.05).The prevalence of pre-hypertension among patients with systolic/diastolic blood pressures of 120-129 mmHg/80-84 mmHg and 130-139 mmHg/85-89 mmHg were 34.90%and 17.16%,*** prevalence of pre-hypertension increased with age,reaching a peak at 30-39 years(39.93%),and then ***-ple risk factors for cardiovascular disease were more common in patients with hypertension and pre-hypertension than in the population with normal blood ***-hypertension was associated with increased fasting blood glucose and increased relative risks of hypertriglyceridemia,hyperuricemia,overweight,obesity,and abdominal obesity,compared with patients who had normal blood ***:The prevalence of pre-hypertension in residents of Chengdu was *** metabolic disorders were already present in the population,and multiple cardiovascular disease risk factors were more common than in the population with normal blood *** screening for cardiovascular risk factors should be performed in patients with *** addition,comprehensive measures,such as lifestyle improvement and medications,should be implemented.

关键词： Pre-hypertension Epidemiological characteristics Multiple metabolic disorders Cardiovascular risk factor Early screening Lifestyle improvement

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

油茶籽粕反刍动物饲料化利用价值初探

中国粮油学报 2017年第10期32卷 111-117页

作者：武月雷陈忠法王佳堃奶业科学研究所浙江大学动物科学学院杭州310058 浙江万里学院生物与环境学院宁波315100

在分析油茶籽粕常规营养成分基础上,本试验采用体外产气和尼龙袋技术对油茶籽粕瘤胃发酵和降解特性进行了评定。结果显示:(1)油茶籽粕的粗蛋白、粗脂肪、中性洗涤纤维、酸性洗涤纤维、酸性洗涤木质素分别为13.1%、8.6%、66.2%、44.5%和2... 详细信息

在分析油茶籽粕常规营养成分基础上,本试验采用体外产气和尼龙袋技术对油茶籽粕瘤胃发酵和降解特性进行了评定。结果显示:(1)油茶籽粕的粗蛋白、粗脂肪、中性洗涤纤维、酸性洗涤纤维、酸性洗涤木质素分别为13.1%、8.6%、66.2%、44.5%和25.4%(绝干物质基础);油茶籽粕的代谢能为4.30 MJ/kg DM;(2)油茶籽粕在体外发酵前期(2~12 h)的累积产气量显著高于羊草(P0.05);(3)油茶籽粕25%替代羊草时不影响潜在产气量(P>0.05),随替代比例的进一步增加(≥50%)慢速产气量显著降低(P0.05)。结果表明油茶籽粕含有较高的粗蛋白和粗脂肪,油茶籽粕替代羊草可提升全混合饲粮的发酵速度,提高丙酸所占挥发性脂肪酸比例;较高含量的木质素降低了其营养价值。

关键词：油茶籽粕反刍动物体外产气尼龙袋木质素

清洁燃料的开发与生产——2000年NPRA年会的中心议题

在线全文

学校读者我要写书评

暂无评论

石油炼制与化工 2000年第8期31卷 1-7页

作者：苗毅关明华罗一斌吴越磊中国石油化工股份有限公司北京100029

综述 2 0 0 0年 (第 98届 )NPRA年会的主要内容 ,重点介绍备受关注的清洁汽油和清洁柴油的生产技术和发展趋势 ,包括生产清洁汽油的脱硫技术、降烯烃技术、降芳烃技术 ,MTBE禁用问题和生产清洁柴油的加氢裂化技术、加氢精制技术等的进展。

关键词：气油总合柴油环境保护 NPRA年会清洁燃料

在线全文

学校读者我要写书评

暂无评论

温州地区百日咳患儿临床特征分析

中华临床感染病杂志 2019年第3期12卷 197-200页

作者：叶万定林乐吴跃雷徐志伟温州医科大学附属第二医院育英儿童医院儿童感染科 325000

目的分析温州地区儿童百日咳病例的临床特征。方法收集2017年11月至2018年10月温州医科大学附属第二医院育英儿童医院收治的百日咳疑似病例875例患儿的病例资料,百日咳确诊患儿188例,根据患儿年龄,分为≤3个月组(n=79)、>3~6个月组(n=59... 详细信息

目的分析温州地区儿童百日咳病例的临床特征。方法收集2017年11月至2018年10月温州医科大学附属第二医院育英儿童医院收治的百日咳疑似病例875例患儿的病例资料,百日咳确诊患儿188例,根据患儿年龄,分为≤3个月组(n=79)、>3~6个月组(n=59)和>6个月组(n=50)。分析各组患儿的一般信息、疫苗接种情况、病程、住院时间、主要临床症状、影像学及实验室检查等情况。采用SPSS 17.0软件对数据进行分析。结果百日咳患儿阳性检出率为21.5%。其中,男女比例为1.2∶1;≤3个月患儿比例最高(42.0%,79/188),其次分别为>3~6个月患儿(31.4%,59/188)、>6个月患儿(26.6%,50/188);春季(32.4%,61/188)和夏季(31.9%,60/188)的比例最高;未接种百日破疫苗者的比例为45.7%(86/188),不完全接种者的比例为23.9%(45/188),完全接种者的比率为30.3%(57/188);47.3%患儿有明确接触史。所有患儿的主要临床表现为咳嗽剧烈面色涨红(96.8%,182/188)、咳末鸡鸣样回声(41.0%,55/134)及咳嗽剧烈呕吐(35.6%,67/188)等。实验室检查发现,99例患儿(52.7%)白细胞数升高,127例(67.6%)淋巴细胞升高。在临床表现方面,≤3个月组患儿咳嗽剧烈发绀的发生率高于>3~6个月组和>6个月组(χ^2=10.264和17.743,P值均3~6个月组和>6个月组患儿咳嗽剧烈发绀的发生率比较,差异无统计学意义(χ^2=1.637,P>0.05)。≤3个月患儿组的住院前病程短于>3~6个月组和>6个月组(q=5.758和4.980,P6个月组患儿住院时间少于≤3个月组和>3~6个月组(q=4.184和2.906,P6月龄患儿住院时间较短。白细胞和淋巴细胞升高对婴幼儿各年龄段百日咳的诊断均具有重要意义。

关键词：百日咳儿童流行病学临床特征

湿热环境对HT3/5222复合材料冲击损伤影响的数值模拟

在线全文

学校读者我要写书评

暂无评论

材料科学与工程学报 2018年第2期36卷 296-300页

作者：姚佳伟吴悦雷牛一凡中国民航大学中欧航空工程师学院天津300300

运用ABAQUS有限元软件建立了HT3/5222碳纤维环氧树脂复合材料层合板的湿热冲击有限元模型,计算了室温干燥环境下不同冲击能量的冲击损伤结果,损伤形状与文献实验结果吻合较好。采用该模型计算分析了温度和吸湿率对层合板冲击损伤的影响... 详细信息

运用ABAQUS有限元软件建立了HT3/5222碳纤维环氧树脂复合材料层合板的湿热冲击有限元模型,计算了室温干燥环境下不同冲击能量的冲击损伤结果,损伤形状与文献实验结果吻合较好。采用该模型计算分析了温度和吸湿率对层合板冲击损伤的影响,结果表明:冲击损伤面积随着温度的升高而增大,且温度越高,增幅越大;温度的升高对低能冲击影响更为严重,20J的冲击能量下,120℃下的损伤面积较20℃扩大了16.3倍;吸湿率对层合板冲击损伤的影响与温度类似,但高湿较高温对冲击损伤的影响更大;温度及吸湿率对层合板初始损伤冲击能量及穿透能量影响显著,初始损伤冲击能量由20℃时的14.7J下降到120℃时的6.2J。

关键词：复合材料冲击数值模拟湿热