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低水平γ射线照射对小鼠骨髓细胞离体增殖效应的影响
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作者 林岐 《中国血液流变学杂志》 CAS 2005年第3期378-379,共2页
目的研究不同剂量低水平γ射线对小鼠骨髓细胞增殖效应的影响。方法小鼠骨髓细胞分别接受0、2、46、、8cGyγ射线照射,照射完毕在37℃水浴中培养3h。然后分成两组,一组测定其CPM值(每分钟放射性计数),一组测定其O2-量。结果小鼠骨髓细... 目的研究不同剂量低水平γ射线对小鼠骨髓细胞增殖效应的影响。方法小鼠骨髓细胞分别接受0、2、46、、8cGyγ射线照射,照射完毕在37℃水浴中培养3h。然后分成两组,一组测定其CPM值(每分钟放射性计数),一组测定其O2-量。结果小鼠骨髓细胞分别经0、2、4、6、8cGy低水平γ射线照射,发现经过6cGy照射后,其增殖效应最明显,其增殖效应和一定剂量范围内低水平γ射线照射所产生O2-量正相关。结论O2-量在一定范围内的增加是小鼠骨髓细胞经低水平γ射线照射所产生增殖效应的十分重要的因素。 展开更多
关键词 水平γ射线 O2- 小鼠骨髓细胞
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牙科机散漏射线辐射水平的检测与评价 被引量:1
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作者 黄海潮 黄丽华 +1 位作者 陈艳 林春培 《中国辐射卫生》 2000年第2期108-108,共1页
关键词 牙科机 散漏射线辐射水平 检测 评价
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黄陂区医用诊断X射线照射水平调查
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作者 孙礼毅 许锋 《中国辐射卫生》 2001年第4期253-254,共2页
关键词 调查 医用诊断X射线照射水平 X线诊断
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低仰角射线对电离层CT成像的影响分析
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作者 赵海生 许正文 吴健 《空间科学学报》 CAS CSCD 北大核心 2011年第1期44-50,共7页
电离层层析成像(Computerized Tomography,CT)是一个有限视角问题,水平射线的缺失造成CT结果垂直分辨率的严重下降.很多人直观地认为低仰角射线可以弥补水平射线的缺失,然而本文的理论分析和数值模拟研究结果表明,低仰角射线对CT结果的... 电离层层析成像(Computerized Tomography,CT)是一个有限视角问题,水平射线的缺失造成CT结果垂直分辨率的严重下降.很多人直观地认为低仰角射线可以弥补水平射线的缺失,然而本文的理论分析和数值模拟研究结果表明,低仰角射线对CT结果的影响十分微小,其无法弥补水平射线缺失所带来的垂直分辨率的下降.模拟结果显示,增加低仰角射线前后CT反演结果几乎没有变化;而去掉680条低仰角射线和高仰角射线后,CT反演结果差别巨大;去掉680条低仰角射线的CT结果与模型吻合很好;去掉680条高仰角射线的CT反演结果失真严重,几乎无法恢复模型的扰动特征. 展开更多
关键词 电离层层析成像(CT) 低仰角射线 有限视角层析 水平射线 垂直分辨率
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浅谈钢管杆两种接地极的计算方法 被引量:3
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作者 秦江伟 胥耀辉 《重庆电力高等专科学校学报》 2010年第2期16-20,共5页
介绍钢管杆采用水平射线型人工接地极和深埋复合型人工接地极两种接地方式,通过分析比较两种接地方式工频接地电阻的计算方法,提出钢管杆在城网建设中的适用性。
关键词 钢管杆 工频接地电阻 复合型人工接地极 土壤电阻率 水平射线型人工接地极
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基于激光扫描的隧道限界侵限检测研究 被引量:15
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作者 杨洪权 何妍 许明 《铁道工程学报》 EI 北大核心 2019年第7期58-63,共6页
研究目的:铁路隧道作为重要的铁路设施,在长期运营期间可能发生形变灾害而影响安全,为杜绝此类灾害发生,隧道限界侵限检测是隧道检测的一项重要内容。随着我国铁路隧道里程不断增加,提高隧道限界侵限检测效率成为提升铁路工务部门工作... 研究目的:铁路隧道作为重要的铁路设施,在长期运营期间可能发生形变灾害而影响安全,为杜绝此类灾害发生,隧道限界侵限检测是隧道检测的一项重要内容。随着我国铁路隧道里程不断增加,提高隧道限界侵限检测效率成为提升铁路工务部门工作质量的一项工作,高效快捷的检测方法必不可少。基于此,本文重点研究基于激光扫描的隧道限界侵限检测技术,旨在利用激光扫描能密集、连续地自动获取大量数据的特点,完成隧道限界侵限的检测及侵限值的计算。研究结论:(1)激光扫描技术可以有效地采集铁路隧道内壁轮廓,作为隧道限界侵限的检测依据,进而判断是否存在限界侵限问题;(2)试验证明,利用激光扫描方法检测隧道内壁轮廓的测量精度达到±4 mm;(3)本研究成果可以有效针对铁路隧道限界侵限问题进行检测,用于指导维修养护工作,可为铁路的安全运营提供帮助。 展开更多
关键词 铁路隧道 侵限检测 激光扫描 水平射线
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基于扫描断面的磁浮轨道限界检测 被引量:3
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作者 姚连璧 张邵华 +1 位作者 聂顺根 阮东旭 《工程勘察》 2021年第2期41-45,共5页
本文介绍了基于扫描仪、IMU等多种传感器的性能,设计了一套磁浮移动扫描集成系统,完成了硬件搭建与各个传感器的数据通讯与采集。结合地铁限界标准,给出以轨道中轴线为中心的磁浮轨道坐标系与其限界轮廓的定义,并根据改进的任意多边形... 本文介绍了基于扫描仪、IMU等多种传感器的性能,设计了一套磁浮移动扫描集成系统,完成了硬件搭建与各个传感器的数据通讯与采集。结合地铁限界标准,给出以轨道中轴线为中心的磁浮轨道坐标系与其限界轮廓的定义,并根据改进的任意多边形水平射线法,判断点是否在凹多边形内,且进行欧氏聚类处理,完成限界检测,给出侵限点集与最近距离,最后由惯导系统提供的坐标进行平曲线里程定位给出侵限里程。在上海同济大学嘉定校区的磁浮试验线现场测试,验证了该方法的可行性。 展开更多
关键词 磁浮 轨道 扫描点云 限界检测 水平射线 聚类 里程定位
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Application of 3D stereotomography to the deep-sea data acquired in the South China Sea:a tomography inversion case 被引量:2
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作者 邢逢源 杨锴 +2 位作者 薛冬 汪小将 陈宝书 《Applied Geophysics》 SCIE CSCD 2017年第1期142-153,191,192,共14页
A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre... A 3D stereotomography algorithm, which is derived from the 3D Cartesian coordinate, is applied for the first time to the deep-sea data acquired in the LH area, South China Sea, to invert a macro velocity model for pre-stack depth migration. The successful implementation of stereotomography is highly dependent on the correct extraction of slowness components and the proper application of regularization terms. With the help of the structure tensor algorithm, a high-quality 3D stereotomography data space is achieved in a very efficient manner. Then, considering that the horizontal slowness in cross-line direction is usually unavailable for 3D narrow-azimuth data, the regularization terms must be enhanced to guarantee a stable convergence of the presented algorithm. The inverted model serves as a good model for the 3D pre-stack depth migration. The synthetic and real data examples demonstrated the robustness and effectiveness of the presented algorithm and the related schemes. 展开更多
关键词 3D stereotomography structure tensor extraction of horizontal components of slowness REGULARIZATION
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二维VTI介质qP波斜率层析方法 被引量:2
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作者 谷巍巍 杨锴 王潇 《石油物探》 EI CSCD 北大核心 2019年第6期828-836,共9页
斜率层析属于立体层析的一种特殊情况,在通过运动学反偏移重建立体层析数据空间的过程中,会出现炮检点位置和旅行时信息已经匹配而地表射线参数水平分量(以下简称地表p x参数)无法匹配的情况,这时可利用p x残差完成对速度模型和反射点... 斜率层析属于立体层析的一种特殊情况,在通过运动学反偏移重建立体层析数据空间的过程中,会出现炮检点位置和旅行时信息已经匹配而地表射线参数水平分量(以下简称地表p x参数)无法匹配的情况,这时可利用p x残差完成对速度模型和反射点坐标的更新。将各向同性介质中的斜率层析方法推广到二维VTI介质qP波情形,利用地表p x参数关于三个各向异性参数的偏导数建立了二维VTI介质qP波斜率层析线性方程组,基于该线性方程组和典型理论数据实施了二维VTI介质qP波斜率层析反演。研究结果表明,VTI介质中的运动学偏移/反偏移与二维VTI介质qP波斜率层析线性方程组相结合,可以实现二维VTI介质的各向异性参数重建,为VTI介质的参数建模提供了一条新的途径。 展开更多
关键词 二维VTI介质qP波 斜率层析 立体层析 运动学偏移/反偏移 射线参数水平分量 各向异性参数重建
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Phase equilibria for the pseudo-ternary system(NaCl+Na2SO4+H2O)of coal gasification wastewater at T=(268.15 to 373.15)K 被引量:8
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作者 Haijiao Lu Jingkang Wang +5 位作者 Jun Yu Yuefeng Wu Ting Wang Ying Bao Dou Ma Hongxun Hao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第7期955-962,共8页
The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal so... The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater. 展开更多
关键词 Pseudo-ternary system Phase equilibria THERMODYNAMICS Waste water Recovery
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Effect of Mg^(2+) content in ion-exchanged Shengli lignite on its equilibrium adsorption water content and its mechanism 被引量:1
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作者 刘祥春 冯莉 +2 位作者 王新华 张营 汤海燕 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第2期456-460,共5页
Mg ion-exchanged samples were prepared with acid-washed Shengli lignite.The chemical composition of the ash of the raw sample was determined by X-ray fluorescence.The equilibrium adsorption water contents of samples w... Mg ion-exchanged samples were prepared with acid-washed Shengli lignite.The chemical composition of the ash of the raw sample was determined by X-ray fluorescence.The equilibrium adsorption water contents of samples were determined in a range of relative humidity.The ion-exchange process was characterized by FT-IR,ash content,and p H value.A possible mechanism is proposed for equilibrium adsorption water of ion-exchanged samples at different humidities.The extent of ion-exchange reaction between Mg2+and lignite is controlled by the concentration of Mg2+in Mg SO4solution.The effect of Mg2+on equilibrium adsorption water content varies with relative humidity and content of Mg2+.The factor that controls equilibrium adsorption water content at low relative humidity is water interactions with sorption sites,which are Mg2+–carboxyl group complex.At middle relative humidity capillary force between Mg2+–water clusters Mg+(H2O)nand capillary is more important.At high relative humidity,free water–free water interactions are more significant. 展开更多
关键词 Ion-exchange FT-IR Equilibrium adsorption water content SURFACE
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The Transcriptional Response of Arabidopsis thaliana L. Genes AtKu70, AtRAD51 and AtRadl to X-Ray Radiation
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作者 Sergey Litvinov Namik Rashydov 《Journal of Agricultural Science and Technology(A)》 2017年第1期52-60,共9页
The study of influence of the fractionated and acute ionizing radiation on plants revealed that it is able to induce genomic instability. The hypothesis that transcription rate of several evolutionary conserved DNA re... The study of influence of the fractionated and acute ionizing radiation on plants revealed that it is able to induce genomic instability. The hypothesis that transcription rate of several evolutionary conserved DNA repair genes AtKu 70, AtRAD51 and AtRadl, which keeps genome stability in cells of model plant Arabidopsis thaliana, changes differently depending on dose and mode of ionizing radiation exposure had been tested. Gel electrophoresis-based reverse transcription polymerase chain reaction (RT-PCR) method was used for quantifying mRNA transcription levels. The data demonstrated that mode and dose of irradiation affect transcription rate of the genes AtKuTO, AtRAD51 and AtRadI. The fractionated and acute X-ray irradiation may result in adaptive response through the induction of key DNA double-strand break (DSB) repair genes AtKu70 and AtRAD51, as well as in genome instability through transcriptional activation of error-prone AtRadl-mediated DNA DSB repair combined with decreased expression of AtRAD51. In plants at doses within the range of 3-9 Gy, an adaptive influence is prevailed, but at doses of 12-21 Gy an error-prone repair of double-strand DNA damage is activated. Fractionation of dose has a significant effect on the transcription of the genes AtKuTO, AtRAD51 and AtRadl only at doses of 15 Gy and 21 Gy. Acute dose of 15 Gy activates error-prone AtRadl-mediated DSB repair and repressed both AtRAD51-dependent and AtKu70-dependent repair pathways, while fractionated irradiation at the same total dose induces more accurate homologous recombination and canonical non-homologous end joining of the DNA strands. In case of A. thaliana exposed to X-rays at dose 21 Gy, the situation is going reversed because of strong induction of the all three genome caretaker genes in leaves of acutely irradiated plants in contrast to the plants under fractionated exposure. 展开更多
关键词 X-ray exposure DNA repair gene expression transcription rate genome instability.
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包头地区天然放射性致环境γ辐射水平及居民受照剂量的调查 被引量:3
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作者 苗金萍 李兴明 《中华放射医学与防护杂志》 CAS CSCD 北大核心 1998年第6期433-435,共3页
包头有开采伴生天然放射性铀、钍的白云鄂博铁矿(C),利用白云矿原料生产的包钢(A)和一个核企业(B)。由于含有放射性的“三废”和物料长年大量排放和露天堆积,影响周围空气、土壤、地下水和生物的放射性水平,使环境地表γ剂... 包头有开采伴生天然放射性铀、钍的白云鄂博铁矿(C),利用白云矿原料生产的包钢(A)和一个核企业(B)。由于含有放射性的“三废”和物料长年大量排放和露天堆积,影响周围空气、土壤、地下水和生物的放射性水平,使环境地表γ剂量率明显增加。为查清包头地区放射性... 展开更多
关键词 天然放射性 环境γ射线水平 居民 受照剂量
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