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Photon Dose Calculation Method Based on Monte Carlo Finite-Size Pencil Beam Model in Accurate Radiotherapy

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Communications in Computational Physics 2013年第10期14卷 1415-1422页

作者： huaqing Zheng Guangyao Sun Gui Li Ruifen Cao xi Pei Liqin hu Gang Song Yican Wu Institute of Nuclear Energy Safety Technology Chinese Academy of SciencesHefeiAnhui230031China Engineering Technology Research Center of Accurate Radiotherapy Anhui ProvinceHefeiAnhui230031China

This study mainly focused on the key technologies,the photon dose calculation based on the Monte Carlo Finite-Size Pencil Beam(MCFSPB)model in the Accurate Radiotherapy System(ARTS).In the MCFSPB model,the acquisition of pencil beam kernel is one of the most important *** this study,by analyzing the demerits of the clinical pencil beam dose calculation methods,a new pencil beam kernel model was developed based on the Monte Carlo(MC)simulation and the technology of medical accelerator energy spectrum *** greatly improved the accuracy of calculated *** to the axial symmetry principle,only part of simulation results was used for the data of pencil beam kernel,which greatly reduced the data quantity of the pencil beam and reduced calculated *** on the above studies,the MCFSPB method was designed and implemented by the Visual C++development *** several tests including the comparisons among the American Association of Physicists in Medicine(AAPM)No.55 Report sample and the ion chamber measurement of lung-simulating inhomogeneous phantom in clinical treatment plan,the results showed that the maximum error of most calculated point was less than 0.5%in the homogeneous phantom and less than 3%in the heterogeneous *** method met the clinical criteria,and would be expected to be used as a fast and accurate dose engine for clinic TPS.

关键词： Accurate radiotherapy dose calculation pencil beam Monte Carlo

Sources and health risks of nitrate pollution in surface water in the Weihe River watershed,China

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Journal of Mountain Science 2022年第8期19卷 2226-2240页

作者： SHI Wen-min ZHANG Yan ZHANG Cheng-qian ZHANG Wen-rui Shaanxi Key Laboratory of Earth Surface System Environmental Carrying Capacity College of Urban and Environmental SciencesNorthwest UniversityXi'an 710127China

Owing to the significant reductions in streamflow and an increase in human activities in recent years,the quality of surface water in Weihe River continues to pose environmental health *** utilized hydrochemistry and nitrogen and oxygen isotopes to elucidate the status and identify sources of nitrate pollution in the south and north banks for three seasons(flood,dry,and mean-flow periods)in the Weihe River watershed.A Bayesian isotope mixing model was applied to estimate the contributions of four potential NO_(3)-sources to river pollution(manure and sewage,soil nitrogen,inorganic fertilizer,and nitrate in precipitation).The *** Protection Agency(USEPA)evaluation model was implemented to evaluate the health risks associated with nitrate pollution in the surface *** pollution was most severe during the dry period because the river flow was *** to the influence of the topography and land use type of the Weihe River,the pollution in the main stream was greater than that of the tributaries,and the pollution of the south bank was greater than that of the north *** the flood and mean-flow periods,δ^(15)N and δ^(18)O were mainly distributed in the NH_(4)^(+) of the fertilizer and soil *** the dry period,δ^(15)N and δ^(18)O were mainly distributed in domestic sewage and manure *** to the Stable Isotope Analysis in R(SIAR)model,manure and sewage were the major nitrate sources during the dry period(73%).However,a decrease in the contribution from domestic sewage and manure was observed during the flood period(45%)compared to the dry period,but with a significantly increased contribution from soil nitrogen(23%)and inorganic fertilizer(21%).The health risk value in the dry period was higher than that in the wet and mean flow periods,and children are more susceptible to nitrate pollution than ***,reducing the discharge of domestic sewage and manure and improving the utilization rate of nitrogen

关键词： Surface water Nitrate pollution Source identification SIAR model Health-risk assessment

挤压316H奥氏体不锈钢大口径管材的晶粒度控制

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金属热处理 2024年第4期49卷 168-174页

作者：贾晓斌秦瑞廷涂明金李媛媛胡永平周仲成北京科技大学新金属材料国家重点实验室北京100083 内蒙古北方重工业集团有限公司内蒙古包头014030 北京科技大学材料科学与工程学院北京100083

系统研究了不同变形量、变形速率、冷却方式、固溶处理温度对316H奥氏体不锈钢晶粒度的影响,并开展了挤压大口径316H奥氏体不锈钢工程化试制。结果表明,变形量越大,晶粒越细小,挤压变形量为80%时,挤压后的晶粒度可达4级以上;在相同变形... 详细信息

系统研究了不同变形量、变形速率、冷却方式、固溶处理温度对316H奥氏体不锈钢晶粒度的影响,并开展了挤压大口径316H奥氏体不锈钢工程化试制。结果表明,变形量越大,晶粒越细小,挤压变形量为80%时,挤压后的晶粒度可达4级以上;在相同变形速率情况下,试样的晶粒尺寸与冷却方式关系明显,水冷、空冷和3 min保温再空冷方式的晶粒尺寸依次增大;在相同的冷却速度条件下,变形速率越快,晶粒尺寸越细小,但随着冷却力度的减弱,晶粒尺寸差距逐渐减少。固溶处理温度对晶粒尺寸长大的作用远大于固溶时间的作用,成形后固溶处理对晶粒的均匀化起到一定的作用,但固溶温度过高会使晶粒迅速长大,固溶处理温度和保温时间应该控制在1050℃和40 min内。

关键词： 316H不锈钢晶粒度挤压温度变形量固溶温度

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二维液相色谱技术在食品检测中的探索应用

云南化工 2024年第7期51卷 154-156页

作者：胡晓琴高娜冯荣荣吴起县白豹市场监督管理所陕西吴起716000 黄陵县市场监管综合执法大队陕西黄陵727300 西安市产品质量监督检验院陕西西安710065

介绍了二维液相色谱技术与高效液相色谱技术的区别,阐述了二维液相色谱技术在食品营养检测、添加剂检测、有毒有害物质检测等方面的应用。利用实例对该技术方法进行了展示,以期对食品安全检测领域提供有效的参考和借鉴。

关键词：食品安全食品检测液相色谱技术

改良Blumgart胰肠吻合在腹腔镜胰十二指肠切除术中的应用

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中国现代普通外科进展 2024年第7期27卷 568-570页

作者：高帅宇王新建张磊崔夕军威海市中心医院肝胆疝与腹壁外科山东威海264200

收集并回顾分析2017年1月以来77例腹腔镜胰十二指肠切除术患者的临床资料。其中35例行改良的Blumgart吻合(改良组),42例行传统的Blumgart吻合(传统组),分析两组临床资料。改良组平均完全吻合时间(36.9±4.7)min,传统组为(39.0±6.2)min... 详细信息

收集并回顾分析2017年1月以来77例腹腔镜胰十二指肠切除术患者的临床资料。其中35例行改良的Blumgart吻合(改良组),42例行传统的Blumgart吻合(传统组),分析两组临床资料。改良组平均完全吻合时间(36.9±4.7)min,传统组为(39.0±6.2)min,两组比较差异无统计学意义(P>0.05)。改良组术后临床性胰瘘(B级和C级)发生率为11.4%(4/35),传统组为21.4%(9/42),两组比较差异无统计学意义(P>0.05)。改良组术后住院时间(10.7±4.9)d,传统组为(14.5±5.3)d,两组比较差异有统计学意义(P<0.05)。改良Blumgart吻合术简化和促进了腹腔镜胰十二指肠切除术中胰肠吻合术的建立,临床性胰瘘的发生率与传统组相似,减少了患者的住院时间。

关键词：腹腔镜胰十二指肠切除术胰肠吻合术 Blumgart吻合 U型缝合胰瘘

基于LSTM-ECGRU的固体火箭发动机性能预测方法

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测控技术 2024年第1期43卷 77-82页

作者：张明楠宫秀良程博胡小梅上海大学机电工程与自动化学院上海市智能制造及机器人重点实验室上海200444 西北工业大学网络空间安全学院陕西西安710072 中国航天科工集团第六研究院六〇一所内蒙古呼和浩特010076 西北工业大学计算机学院陕西西安710072

随着数据挖掘技术、测量技术的不断发展,为了满足火箭发动机参数探索的需要,使用数据挖掘技术利用历史数据对发动机各种参数进行预测成为火箭发动机在数据探索方面新的发展方向。同时,火箭发动机的地面点火试验在向着尽可能还原真实运... 详细信息

随着数据挖掘技术、测量技术的不断发展,为了满足火箭发动机参数探索的需要,使用数据挖掘技术利用历史数据对发动机各种参数进行预测成为火箭发动机在数据探索方面新的发展方向。同时,火箭发动机的地面点火试验在向着尽可能还原真实运行环境的方向发展。基于以上情况,引入在地面点火试验中的环境因素与设计因素共同作为模型的输入变量,以此来补充环境因素对性能参数的影响。根据试验对象数据特性,使用长短期记忆(Long Short-Term Memory,LSTM)神经网络对性能进行初步预测。为了能够减少整体模型误差和引入环境因素带来的误差,提高模型预测精度和泛化能力,提出了基于误差修正分析和趋势判断的误差修正门控单元(Error Correction Gate Recurrent Unit,ECGRU)神经网络模型对初步预测结果进行误差修正。同时结合环境参数特点,设计规划ECGRU模型输入、输出参数的计算规则。基于历史试验数据完成对比试验,验证了新模型具有较高的预测精度和泛化能力。

关键词：性能预测 LSTM ECGRU 误差修正

药物涂层球囊扩张成形术对下肢动脉硬化闭塞症患者血流重建及踝肱指数的影响

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山西医药杂志 2024年第2期53卷 109-112页

作者：胡凯锋赵亮高原吴俊哲西安交通大学第一附属医院血管外科 710089 不详

目的探讨药物涂层球囊扩张成形术对下肢动脉硬化闭塞症患者血流重建及踝肱指数的影响。方法选取西安交通大学第一附属医院血管外科2021年7月至2022年8月选择入组的100例下肢动脉硬化闭塞症患者为研究对象,按照随机数字表法分为2组,各50... 详细信息

目的探讨药物涂层球囊扩张成形术对下肢动脉硬化闭塞症患者血流重建及踝肱指数的影响。方法选取西安交通大学第一附属医院血管外科2021年7月至2022年8月选择入组的100例下肢动脉硬化闭塞症患者为研究对象,按照随机数字表法分为2组,各50例。对照组患者采用普通球囊扩张成形术治疗,观察组患者实施药物涂层球囊扩张成形术治疗,2组术后均随访6个月。对比2组患者的治疗效果、Rutherford分级、血清水平、血流重建、晚期管腔丢失情况、不良事件。结果术后6个月,观察组的踝肱指数(0.94±0.26)、最小管腔直径(3.47±0.39)mm、一氧化氮(NO)(30.3±4.0)pg/ml、世界卫生组织生存质量测定量表(WHOQOL-BREF)(80.1±3.5)分均高于对照组的(0.86±0.11)、(3.13±0.32)mm、(26.8±3.6)pg/ml、(68.1±3.1)分,观察组的Rutherford分级(0.19±0.05)、血清内皮素-1(ET-1)(70±7)pg/ml、血浆P选择素(30.2±3.5)μg/L、晚期管腔丢失(1.24±0.25)mm低于对照组的(1.42±0.10)、(77±7)pg/ml、(37.3±3.9)μg/L、(2.51±0.36)mm,差异均有统计学意义(P0.05);观察组的不良事件发生率为4%,低于对照组的16%,差异有统计学意义(P<0.05)。结论相比于普通球囊扩张成形术治疗,采用药物涂层球囊扩张成形术应用于下肢动脉硬化闭塞症患者效果更佳,能够有效改善Rutherford分级,提高踝肱指数,降低肢内再狭窄、晚期管腔丢失及不良事件的发生率,值得推广。

关键词：闭塞性动脉硬化药物涂层球囊扩张成形术血流重建踝肱指数不良事件

Effect of tillage and burial depth and density of seed on viability and seedling emergence of weedy rice

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Journal of Integrative Agriculture 2019年第8期18卷 1914-1923页

作者： ZHANG Zheng GAO Ping-lei DAI Wei-min SONG xiao-ling hu Feng QIANG Sheng Weed Research Laboratory Nanjing Agricultural University Nanjing 210095 P.R.China College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 P.R.China

Weedy rice(Oryza sativa f. spontanea) is one of the three worst paddy weeds in most rice growing areas. The unexpected heavy infestation is derived from a persistence of soil seed bank of weedy rice, which the shattered seeds chiefly feed back to. Information on soil seed bank dynamics is imperative to predict the infestation of weeds. In the present paper,the effect of rotary tillage on weedy rice seed bank structure was studied first, and a burial experiment of marked seeds was conducted to observe the overwintering survival, seed viability and seedling emergence of weedy rice. The results showed that the proportion of weedy rice seeds in deeper soil increased but seedling emergence decreased with increasing plowing depth. The viability of weedy rice seeds decreased as the burial duration time extended but more slowly in deeper soil layers. Additionally, there was no significant effect of burial density on seed viability. Moreover, the logistic model fitted well(R^2≥0.95, P≤0.01) with the depressive trends of seed viability with increasing burial time under all burial depths and densities which can provide us further information about seed survival. In field experiments, number of seedling emergence significantly decreased as seed burial depth increased, conversely, proportion of seedling emergence increased as seed burial density decreased. This study has important implications for determining strategies for weedy rice management by exhausting its seed bank through the alteration of tillage practices.

关键词： seed burial depth seed burial density germination wintering survival seed vertical distribution

数据和知识双驱动下的土压平衡盾构结泥饼事件预警模型

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隧道建设（中英文） 2022年第8期42卷 1365-1374页

作者：胡珉王伊沈辉上海大学悉尼工商学院上海201800 上海大学-上海城建集团建筑产业化研究中心上海200072 上海隧道工程有限公司上海200032

针对施工中结泥饼事件成因机制复杂、预判难度大的问题,从数据建模和知识推理2种角度综合判断盾构结泥饼事件概率。从数据建模角度,采用无阈值递归图转换和极限学习机自编码器技术建立基于施工多维时序数据的结泥饼异常诊断子模型;从知... 详细信息

针对施工中结泥饼事件成因机制复杂、预判难度大的问题,从数据建模和知识推理2种角度综合判断盾构结泥饼事件概率。从数据建模角度,采用无阈值递归图转换和极限学习机自编码器技术建立基于施工多维时序数据的结泥饼异常诊断子模型;从知识推理角度,提取土压平衡盾构结泥饼事件规则,形成事件诊断知识库,建立基于历史施工经验的结泥饼事件诊断子模型。基于2个子模型输出结果,采用综合概率法,建立数据和知识双驱动的结泥饼事件预警模型。实际工程应用表明:数据和知识双驱动的预警模型能够有效预测结泥饼事件,且预警效果优于单一形式的子模型,较子模型的误报率更低,预警时间早于人工发现的结泥饼事件,为工程安全提供了技术保障。

关键词：结泥饼土压平衡盾构数据驱动知识驱动异常诊断预警模型