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多排螺旋CT剂量效率的体模研究 被引量:2
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作者 庄静文 白玫 侯艺威 《中国医疗设备》 2014年第11期41-42,71,共3页
目的:研究CTDI100表征CT检查所致辐射剂量的准确性。方法使用长杆电离室测量不同准值宽度、螺距以及管电压下体模内剂量分布曲线并计算CT剂量效率。结果 CT剂量效率范围为79%~94%,其中,中心位置的CT剂量效率范围为79%~87%,边缘4个... 目的:研究CTDI100表征CT检查所致辐射剂量的准确性。方法使用长杆电离室测量不同准值宽度、螺距以及管电压下体模内剂量分布曲线并计算CT剂量效率。结果 CT剂量效率范围为79%~94%,其中,中心位置的CT剂量效率范围为79%~87%,边缘4个位置的CT剂量效率范围为79%~94%,加权CT剂量效率范围为82%~90%。准直宽度与螺距越大,CT剂量效率越低;CT剂量效率受管电压影响不明显。结论CTDI100与CTDI∞之间存在一定差异,CTDI100、CTDIw表征CT检查所致辐射剂量的准确度随准直宽度和螺距的增大而降低。 展开更多
关键词 CTDI100 多排螺旋CT 准直宽度 CT剂量效率
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关于多排螺旋CT剂量的探讨 被引量:20
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作者 王晓峰 彭明辰 《医疗设备信息》 2004年第12期23-25,20,共4页
随着螺旋CT探测器排数的增加 ,病人所受辐射剂量也出现了新的变化。本文就多排螺旋CT的剂量表征、测量进行了探讨 ,对其临床诊断剂量参考水平进行了调研。分析了多排螺旋CT管球对热容量的要求以及其剂量效率的变化。最后提出了在不降低... 随着螺旋CT探测器排数的增加 ,病人所受辐射剂量也出现了新的变化。本文就多排螺旋CT的剂量表征、测量进行了探讨 ,对其临床诊断剂量参考水平进行了调研。分析了多排螺旋CT管球对热容量的要求以及其剂量效率的变化。最后提出了在不降低影像质量的情况下如何降低病人剂量的方法。 展开更多
关键词 辐射剂量 多排螺旋CT 螺距 CTDIvol 剂量效率 DRL
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LiF热释光剂量计对49.3MeV/u ^(12)C离子束辐射的剂量响应初步研究 被引量:1
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作者 李强 王桂玲 +4 位作者 卫增泉 李文建 党秉荣 王菊芳 周光明 《核技术》 CAS CSCD 北大核心 1999年第10期636-639,共4页
用LiF(M,Ti)热释光剂量计测量了兰州重离子研究装置提供的49.3MeV/u12C离子束辐射的剂量响应.结果发现,离子注量在1×107-2×108/cm2时,LiF对碳离子束的剂量响应效率η变化幅度不大,平均值为57%。提示LiF可用于一... 用LiF(M,Ti)热释光剂量计测量了兰州重离子研究装置提供的49.3MeV/u12C离子束辐射的剂量响应.结果发现,离子注量在1×107-2×108/cm2时,LiF对碳离子束的剂量响应效率η变化幅度不大,平均值为57%。提示LiF可用于一定离子注量范围内吸收剂量的测量,并且该结果与德国GSI通过重离子径迹结构理论模型计算得到的热释光剂量计对50MeV/u12C离子束的η=54%基本一致。 展开更多
关键词 热释光剂量 剂量响应效率 剂量响应 氟化锂
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基于剂量传输过程分析的草甘膦可溶液剂配方研究 被引量:2
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作者 郭勇飞 张晨辉 +1 位作者 高玉霞 杜凤沛 《现代农药》 CAS 2020年第6期27-33,共7页
基于农药药液剂量传输过程,研究分析雾滴与靶标表面的固-液界面作用,建立快速筛选配方的新方法。选择功能高分子助剂G-801制备得到理化性质稳定的41%草甘膦异丙胺盐可溶液剂,分析药液在石蜡板表面的沉积过程,筛选出黏附力高、沉积量大... 基于农药药液剂量传输过程,研究分析雾滴与靶标表面的固-液界面作用,建立快速筛选配方的新方法。选择功能高分子助剂G-801制备得到理化性质稳定的41%草甘膦异丙胺盐可溶液剂,分析药液在石蜡板表面的沉积过程,筛选出黏附力高、沉积量大、静态表面张力和平衡接触角适中的配方进行田间药效试验评价。结果表明,在各处理剂量下,配方制剂对阔叶类杂草和莎草类杂草的株防效和鲜重防效均接近100%;在中高处理剂量下,配方制剂对禾本科杂草的株防效和鲜重防效高于95%,获得较优配方。因此,基于剂量传输的农药制剂快速评价方法,能科学、准确筛选配方,减少田间药效试验次数,促进农业绿色可持续发展。 展开更多
关键词 草甘膦 剂量传输效率 沉积量 黏附力 田间防效
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Influence of Energy on Solvent Diffusion in Polymer/Solvent Systems 被引量:1
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作者 胡慧俊 蒋文华 韩世钧 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第4期459-463,共5页
The Vrentas-Duda free-volume theory has been extensively used tocorrelated or predict the solvent diffusion coefficient of apolymer/solvent system. The energy term in the free volume diffusionequation is difficult to ... The Vrentas-Duda free-volume theory has been extensively used tocorrelated or predict the solvent diffusion coefficient of apolymer/solvent system. The energy term in the free volume diffusionequation is difficult to estimate, so the energy term was usuallyneglected in previous predictive versions of the free volumediffusion coefficient equation. Recent studies show that the energyeffect is very important even above the glass transition temperatureof the system. In this paper, a new evaluating method of the energyterm is proposed, that is, the diffusion energy at different solventconcentrations is assumed to be a linear function of the solventdiffusion energy in pure solvents and that in polymers under thecondition that the solvent in infinite dilution. 展开更多
关键词 solvent diffusion in polymer PREDICTION energy effect
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The Three-region Method of Color Matching in the Presence of Fluorescent Whitening Agents 被引量:1
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作者 李戎 顾峰 陈东辉 《Journal of Donghua University(English Edition)》 EI CAS 2005年第4期123-128,共6页
An expression of reflectance of fluorescent dyes in emission region was used in this article. Through the analysis of the spectral radiance factor of fluorescent whitening agents(FWA), the color matching of FWA was st... An expression of reflectance of fluorescent dyes in emission region was used in this article. Through the analysis of the spectral radiance factor of fluorescent whitening agents(FWA), the color matching of FWA was studied and the three-region method of color matching method was put forward. The method was proved to be reliable for the dyes used and was easy to apply for the color matching of FWAs. 展开更多
关键词 fluorescent whitening agents fluorescent quantum efficiency color matching.
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Dietary Leucine Requirement for Juvenile Large Yellow Croaker Pseudosciaena crocea (Richardson,1846) 被引量:4
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作者 LI Yan AI Qinghui MAI Kangsen XU Wei CHENG Zhenyan HE Zhigang 《Journal of Ocean University of China》 SCIE CAS 2010年第4期371-375,共5页
Dietary leucine requirement for juvenile large yellow croaker, Pseudosciaena crocea Richardson 1846 (initial body weight 6.0 g±0.1 g) was determined using dose-response method.Six isonitogenous (crude protein 43%... Dietary leucine requirement for juvenile large yellow croaker, Pseudosciaena crocea Richardson 1846 (initial body weight 6.0 g±0.1 g) was determined using dose-response method.Six isonitogenous (crude protein 43%) and isoenergetic (19 kJ g-1) practical diets containing six levels of leucine (Diets 1-6) ranging from 1.23% to 4.80% (dry matter) were made at about 0.7% increment of leucine.Equal amino acid nitrogen was maintained by replacing leucine with glutamic acid.Triplicate groups of 60 individuals were fed to apparent satiation by hand twice daily (05:00 and 17:30).The water temperature was 26-32℃, salinity 26-30 and dissolved oxygen approximately 7 mg L-1 during the experimental period.Final weight (FW) of large yellow croaker initially increased with increasing level of dietary leucine but then decreased at further higher level of leucine.The highest FW was obtained in fish fed diet with 3.30% Leucine (Diet 4).FW of fish fed the diet with 4.80% Leucine (Diet 6) was significantly lower than those fed Diet 4.However, no significant differences were observed between the other dietary treatments.Feed efficiency (FE) and whole body composition were independent of dietary leucine contents (P>0.05).The results indicated that leucine was essential for growth of juvenile large yellow croaker.On the basis of FW, the optimum dietary leucine requirement for juvenile large yellow croaker was estimated to be 2.92% of dry matter (6.79% of dietary protein). 展开更多
关键词 Pseudosciaena crocea LEUCINE REQUIREMENT DIETS
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Removal of Turbidity and COD from a Synthetic Water Sample by Coagulation 被引量:2
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作者 Melina Kotti Androniki Papafilippaki George Stavroulakis 《Journal of Environmental Science and Engineering(A)》 2012年第11期1243-1247,共5页
The main objective of this research was to study the removal of turbidity and COD (chemical oxygen demand) from a synthetic water sample. The water sample was treated chemically by coagulation. Two inorganic coagula... The main objective of this research was to study the removal of turbidity and COD (chemical oxygen demand) from a synthetic water sample. The water sample was treated chemically by coagulation. Two inorganic coagulants were used, ferric chloride and the double salt potassium-aluminium sulphate. The optimum coagulant dosage and working pH were examined. The results for ferric chloride as coagulant showed that the maximum removal efficiency (%) of COD was achieved at pH 6 with a dosage of 100 mg-L-1 and the maximum removal efficiency (%) of turbidity at pH 5 with a dosage of 500 mg.L-1. For double salt, as coagulant, the maximum removal efficiencies (%) of COD and turbidity were achieved at pH 6 with a dosage of 3,500 mg.L-1. An extensive comparison with results from previous studies was also described in this research. 展开更多
关键词 COAGULATION colloidal particles ferric chloride potassium aluminium sulphate water treatment.
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Monotricat, Innovative Displacement Hull High Hydrodynamic Efficiency and Energy Recovery, Navigating at Speeds of Planing Hulls on Spray Self-produced
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作者 Luigi MASCELLARO 《Journal of Shipping and Ocean Engineering》 2015年第5期229-241,共13页
The need to have naval units ever faster pushed the ship design to design hull shapes with increasingly higher performance thanks to the use of lightweight materials such as aluminum, and more powerful engines, etc., ... The need to have naval units ever faster pushed the ship design to design hull shapes with increasingly higher performance thanks to the use of lightweight materials such as aluminum, and more powerful engines, etc., but without substantially modifying the traditional forms of hull. The hull patented Monotricat high hydrodynamic efficiency and energy saving it represents an evolution of the traditional architectures of the hulls, as its shape is adapted to recover wave formation engendered from the bow and sprays associated with it so as to reduce the resistance to the benefit of the speed, and navigating in displacement at speeds of planing hulls with an efficiency of about 20%. The patented hull Monotricat represents the overcoming of distinction between displacement and planing hulls, because, unlike previous solutions, the hull conventionally called Monotricat is the first displacement hull that can navigate at both displacement and planning speeds, with a resistance curve almost straight, maintaining the characteristics of a displacement hull, since it combines the characteristics of displacement and planning hull. It presents an innovative architecture that could be defined as a hybrid between a monohull and catamaran, navigating on spray self-produced. The combination of these three types of naval hulls allows it to ensure: safety, comfort navigation, best seakeeping and maneuverability in restricted waters, stability, reduction of resistance to motion, cost management, regularity on the routes even in adverse weather-sea. These characteristics of the hull have been studied, tested and validated by leading research institutes and universities with more ameliorative results in each subsequent experimentation, reported in the present work, which demonstrated a greater hydrodynamic efficiency compared to conventional hulls of 20%. 展开更多
关键词 Innovative naval hull energy recovery hydrodynamic efficiency displacement hull planing hull spray self-produced resistance curve straight line.
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Effect of Tree Species and Dosage of Rhizomorph Wood on Asexual Propagation of Wild Gastrodia elata. Bl. f. glauca S. Chow in Ganzi
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作者 Xueqiang XIE 《Agricultural Science & Technology》 CAS 2015年第9期1840-1844,共5页
The effects of the tree species and the dosages of Armillariella mellea rhizomoph wood on asexual propagation of wild Gastrodia elata Bl. f. glauca S. Chow were studied in Ganzi prefecture. The results showed that tre... The effects of the tree species and the dosages of Armillariella mellea rhizomoph wood on asexual propagation of wild Gastrodia elata Bl. f. glauca S. Chow were studied in Ganzi prefecture. The results showed that tree species had a very significant effect on asexual reproduction yield of wild Gastrodia elata Bl. f. glauca S. Chow. The drying rate and yield of Gastrodia elata Bl. f. glauca S. Chow cultured by close grained woods such as Quercus spinosa David ex Fr. was extremely significant higher than that cultured by coarse grained wood such as Betula platyphylla Suk. The dosage had a very significant effect on the yield of wild Gastrodia elata Bl. f. glauca S. Chow whereas it had no influence on the drying rate. 展开更多
关键词 Tree species of Armillariella mellea rhizomoph wood Dosage of Armil- lariella mellea rhizomorph wood Gastrodia elata BI. f. glauca S. Chow Asexual propagation Yield Drying rate
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Laminar Diffusion Flames of Methane in a Co-annular Jet of Oxygen-Enriched Air
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作者 Pascale Gillon May Chahine Brahim Sarh 《Journal of Energy and Power Engineering》 2013年第1期32-40,共9页
Oxygen rich combustion is a mean to increase the energy efficiency and to contribute to CO2 capture. Influence of oxygen enriched air on the stability of methane flames from non premixed laminar jets has been investig... Oxygen rich combustion is a mean to increase the energy efficiency and to contribute to CO2 capture. Influence of oxygen enriched air on the stability of methane flames from non premixed laminar jets has been investigated experimentally. The burner consists of two coaxial jets: methane flowing out of the inner, oxidizer from the outer. The flame behavior is studied according to the proportion of oxygen in the oxidizer jet, the oxidizer and the methane jets velocities. The flame is either anchored to the burner, lifted, stationary or not or blown-out. The addition of oxygen produces a decrease of the lift height, a reduction of the length of the reaction zone and an increase in the soot emission. These results have been reported into diagrams of stability where the flame configurations are connected to the competition between the dynamic effect of the injection velocity and the chemical effect of oxygen addition. 展开更多
关键词 Oxygen-enriched air methane diffusion flame lifted flame flame propagation speed.
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Testing of separating catalyst from resid fluid catalytic cracking slurry by 10 mm hydrocyclones
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作者 ZHOU Ping BAI Zhi-shan ZHANG Yan-hong YANG Qiang MA Ji WANG Hua-lin 《Journal of Energy and Power Engineering》 2007年第1期63-67,共5页
The paper focuses on removing catalyst solids from oil slurry using 10 mm hydrocyclones, and aims to test the feasibility of the solution. An industrial sidetrack tester of residual oil separation by hydrocyclones was... The paper focuses on removing catalyst solids from oil slurry using 10 mm hydrocyclones, and aims to test the feasibility of the solution. An industrial sidetrack tester of residual oil separation by hydrocyclones was set up in 1.8 Mt/a resid fluid catalytic cracking (RFCC) unit, the effect of pressure drop, separation efficiency and inlet flowrate were studied. It was observed that an increase in feed flowrate will decrease the pressure drop ratio, and with an increase in feed flowrate, separation efficiency increases gradually. Under the condition that feed fiowrate was ranging from 250L/h to 270L/h, the separation efficiency was 45.77%-82.80%, the recovery rate of catalyst solid panicles was increased from 10 20% of electrostatic catalyst separator to 50 80%. Thus, it is feasible to separate the slurry by using the miniature hydrocyclones in RFCC unit. 展开更多
关键词 HYDROCYCLONE solid-liquid-separation catalytic cracking CATALYST SEPARATION
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宽束多排螺旋CT剂量的测量研究 被引量:13
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作者 徐辉 王建超 +2 位作者 黄卓 岳保荣 冯泽臣 《中国辐射卫生》 2017年第6期623-626,636,共5页
目的研究宽束多排螺旋CT标称线束宽度与CT剂量指数(CTDI)测量效率的关系,为完善我国CT质量控制检测规范提供数据支持。方法在一台128排螺旋CT上,分别使用100 mm笔形电离室和150 mm长PMMA体模组合,以及300 mm长杆电离室和450 mm长PMMA体... 目的研究宽束多排螺旋CT标称线束宽度与CT剂量指数(CTDI)测量效率的关系,为完善我国CT质量控制检测规范提供数据支持。方法在一台128排螺旋CT上,分别使用100 mm笔形电离室和150 mm长PMMA体模组合,以及300 mm长杆电离室和450 mm长PMMA体模组合,测量从5~80 mm不同线束宽度下的CTDI_(100)和CTDI_(300);用CTDI_(300)近似代替CTDI_∞,计算CTDI测量效率。利用IEC和IAEA出版物中建议的公式计算CTDI_(100),NT,比较计算值与CTDI_(300)的差异。结果不同线束宽度时模体中心位置的CTDI_(100)的数值与CTDI_(300)之间存在明显差异,随着线束宽度的增大CTDI测量效率随呈下降趋势,CTDI_(100)与CTDI_(300)的比值从线束宽度5 mm时的0.62,在线束宽度为80 mm时CTDI测量效率降至0.56。通过IEC和IAEA的修正公式,可以使CTDI_(100,NT)与CTDI_∞的比值保持在一个相对恒定的水平。结论目前广泛使用的CT辐射剂量表征量对评价宽束多排螺旋CT剂量时缺乏准确性,通过修正公式能在一定程度上表征宽排CT探测器的剂量水平,关于如何准确表达宽束CT的剂量并采用简单的方法对其准确测量,国际社会仍然在进一步的研究中。 展开更多
关键词 宽束多排螺旋CT 线束宽度 CT剂量指数测量效率 CT剂量指数
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ZnO hierarchical aggregates: Solvothermal synthesis and application in dye-sensitized solar cells 被引量:6
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作者 Jianxing Shi Yunxin Liu Qing Peng Yadong Li 《Nano Research》 SCIE EI CAS CSCD 2013年第6期441-448,共8页
ZnO hierarchical aggregates have been successfully synthesized by solvothermal methods through reaction of zinc acetate and potassium hydroxide in methanol solution. The shapes of the aggregates were controlled by var... ZnO hierarchical aggregates have been successfully synthesized by solvothermal methods through reaction of zinc acetate and potassium hydroxide in methanol solution. The shapes of the aggregates were controlled by varying the ratio of Zn2~ and OH- ions in the reaction system, while the size can be tuned from 2μm to 100 nm. Oriented attachment was found to be the main mechanism of the three-dimensional assembly of small ZnO nanocrystallites into large aggregates. The performance of these aggregates in dye-sensitized solar cells (DSCs) indicated that hierarchical structured photoelectrodes can increase energy conversion efficiency of DSCs effectively when the sizes of aggregates match the wavelengths of visible light. 展开更多
关键词 dye-sensitized solar cells zinc oxide hierarchical aggregate solvothermal synthesis light scattering
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