Determination of specific activity of230Th in uranium ore samples

A new method suitable for determining specific activity of²³⁰Th in uranium ore samples is built. The method is characterized by adding the²³⁰Th/²³²Th standard dilution agent with lower activity ratio (Its²³⁰Th/²³²Th activity ratio and²³⁰Th have been known) to the samples and using isotopic dilution analysis. The method can be applied to analyses of²³⁰Th specific activity in various²³⁰Th/²³²Th activity ratio samples. The precision can also be improved.     

东太平洋多金属结核U、Th同位素深度分布特征与生长速率

研究了东太平洋多金属结核中Ｕ、Ｔｈ同位素的深度分布与生长速率。表明,东太平洋多金属结核中的＾２３４Ｕ／＾２３８Ｕ）Ａ．Ｒ．与海水接近,证实了Ｕ的海水来源;２３４Ｕ及２３８Ｕ的活度并不随深度增加而减小,而是在次表层和更深层出现极大值。２３６７站核中＾２３２Ｔｈ的活度在次表层有最大值,之后随深度的增加而降低,反映了结核生长过程中成岩作用的影响;１７９７站南结核中＾２３２Ｔｈ表层有最大值,其它各层的变化     

Downcutting and uplifting in the middle part of Qinling orogenic belt during the late Quaternary

Layered cave passages formed on the walls of the Qianyou River valley in the middle part of the Qinling Mountains since the Pleistocene due to the intermittent uplifts. 12 speleothem samples near ruins of palaeowater tables in 3 cave passages are dated by using the 230Th method. The results show that the 3 caves began to uplift (358±38) ka, (247±28) ka, (118±19) ka ago respectively. Given the differences of elevation between the caves, we could obtain the downcutting rates of the valley: (0.23(0.02) mm/a during 358-247 ka, (0.19(0.03) mm/a during 247-118 ka, and (0.51(0.08) mm/a since 118 ka. This implies that more andmore strong uplifting sustained in the middle part of Qinling since 358 k     

U-series dating on late Quaternary sediments from Balikun Lake

The U-series component-dating method has been employed to date the sediment core B-194 from Balikun Lake. 230Th/ 232Th and 234U/ 232Th ratios in various components of the samples dissolved in different concentration acids were measured respectively. The results indicate that there is a good relationship of the isotopic ratios between the solutions and the residues, and that uranium and thorium isotopic fractionations did not occur during acid leaching. Based on the U-series ages obtained by using component-dating method, a 144-ka time sequence was established corresponding to the upper 25-m interval of the B-194 core, which is in agreement with palaeomagnetic dating results. The fact that the palaeoclimatic and palaeoenvironmental record labeled with U-series ages is correlative with the deep-sea δ 18O SPECMAP also demonstrates that the U-series component-dating method can be used to date lake sediments.     

花生油质量检测仪的设计

本文设计了一种根据吸光度原理,检测花生油纯度的仪器。当花生油结晶时,光源发出的光通过样品油后被光频转换器TSL230接收。TSL230输出与输入光强相关的频率脉冲,再测出入射光直接被TSL230接收所得到的频率脉冲,两次频率值相比,得到与吸光度对应的数值。因为吸光度与样品油的纯度有关,所以可以通过频率,了解样品油的纯度情况。     

Abrupt climate change of EastAsian Monsoon at 130 kaBP inferred from a high resolu-tion stalagmite δ18O record

^230Th ages and oxygen isotope data of a stalagmite from Shanbao Cave in Hubei Province characterize the East Asian Monsoon precipitation from 133 to 127ka. The decadal-scale high-resolution δ^18O record reveals a detailed transitional process from the Penultimate Glaciation to the Last Interglaciation. As established with ^230Th dates, the age of the Termination Ⅱ is determined to be 129.5±1.0 kaBP, which supports the Northern Hemisphere insolation as the triggers for the ice-age cycles. In our δ^18O record, the glacial/interglacial fluctuation reaches about 4‰, almost the same level as in other Asian Monsoon cave stalagmite δ^18O records. The transition of the glacial/interglacial period in our record can be recognized as four stepwise stages, among which, a rapid rise of monsoon precipitation follows the stage of “Termination Ⅱ pause”. The rapid rise is synchronous with the abrupt change of global methane concentration, which reflects that an increase in both Asian Monsoon precipitation and tropical wetland plays an important role in the global climate changes.     

High-precision thermal ionization mass spectrometry dating of young volcanic rocks by using U-series method

A high precision thermal ionization mass spectrometric (HP-TIMS) technique is used to determine²³⁸U,²³⁴U,²³²Th,²³⁰Th concentrations and their ratios in whole rocks and minerals separated from Quaternary Maanshan, Dayingshan and Heikongshan volcanic rocks of Tengchong volcanic field, Yunnan Province, China. The²³⁸U-²³⁰Th isochrons are given, yielding four age values (227±20) ka (D-1, Dayingshan), (79.6±5.5) ka (D-7, Dayingshan), (21.9±3.0) ka (h-1, Heikongshan), and (7.5±1.0) ka (M-1, Maanshan). The result is not only consistent with but also preciser than those measured by the K-Ar method and the alpha spectrometry U-series method, indicating that the HP-TIMS method is reliable and has high precision. Besides, a procedure of HP-TIMS analysis of young volcanic rocks in China is set up preliminarily.     

热敏灸对人体免疫失衡影响的实验研究

募集17名受试者,随机分为对照组和热敏灸组,进行一周的高强度集训.期间,对照组每天运动后进行20 min的推拿按摩,热敏灸组每天运动后在双侧足三里处实施20 min的热敏灸治疗.采用ELISA法测定两组受试者集训前、末次训练后2 h与末次训练后3 d肘正中静脉血IFN-γ、IL-4、IL-12、IL-10、IL-12p40的含量;在热敏灸足三里治疗过程中,采集受试者红外热成像图形,分析热敏灸对穴位周围温度的影响.结果发现,热敏灸疗法可通过温热刺激和红外辐射等方式刺激穴位,提高IFN-γ/IL-4比值,调节IL-12及其抑制剂IL-10与IL-12p40的分泌,促进Th1细胞的分化过程,从而纠正过度疲劳所致的Th1/Th2失衡状态.     

基于孟塞尔系统岩石颜色定量分析研究

基于岩石颜色描述特点,阐述颜色测量的基本原理、相关色度学内容及石油地质岩石颜色标准。以TCS230颜色传感器为基础,选用C照明体提供标准照明光源,及CY7C68013A为主控芯片的单片机设计控制器系统;采用漫反射积分球为几何观测条件,进行光电积分式测量和光电信号转换获取颜色信息;对RGB色彩空间与孟塞尔颜色系统进行转换后,将色样投影到RGB色彩空间上得到近似均匀划分的mRGB色彩空间;最终得到按照石油地质岩石颜色标准输出的颜色定量测量系统。实现了岩石颜色从定性到半定量分析,精确的颜色描述可以反映主要矿物类型和沉积环境,对野外地质工作具有重要的指导意义。     

平版表格印刷中的免配页自动打码控制系统

介绍了平版表格印刷技术中免配页自动打码控制系统的硬件和软件系统结构。重点分析了该系统面临的问题及其解决方法。对颜色传感器TCS230在系统中的使用方法作了详细介绍。     

The U/Th production ratio and the age of the Milky Way from meteorites and Galactic halo stars

Some heavy elements (with atomic number A > 69) are produced by the 'rapid' (r)-process of nucleosynthesis, where lighter elements are bombarded with a massive flux of neutrons. Although this is characteristic of supernovae and neutron star mergers, uncertainties in where the r-process occurs persist because stellar models are too crude to allow precise quantification of this phenomenon. As a result, there are many uncertainties and assumptions in the models used to calculate the production ratios of actinides (like uranium-238 and thorium-232). Current estimates of the U/Th production ratio range from approximately 0.4 to 0.7. Here I show that the U/Th abundance ratio in meteorites can be used, in conjunction with observations of low-metallicity stars in the halo of the Milky Way, to determine the U/Th production ratio very precisely (0.57(+0.037)(-0.031). This value can be used in future studies to constrain the possible nuclear mass formulae used in r-process calculations, to help determine the source of Galactic cosmic rays, and to date circumstellar grains. I also estimate the age of the Milky Way (14.5(+2.8)(-2.2)Gyr in a way that is independent of the uncertainties associated with fluctuations in the microwave background or models of stellar evolution.     

海洋沉积物同位素年代测定技术发展现状分析

海底沉积物很好地记录了地质历史,根据“将今论古”原则对其进行研究,对了解海洋的形成和演变具有关键意义。本文叙述了国内外海洋沉积物同位素年代学的研究进展,分析了当前常用几种定年技术如14C法、230Th法、231Pa/220Th法等的适用性和局限性,讨论了海洋沉积物同位素定年过程中存在的一些问题,指出准确定年的注意事项。     

颜色检测系统及其在果蔬干燥中的应用

设计了一种基于TCS230颜色传感器和LabVIEW的颜色检测系统.并依次利用白平衡、矩阵校正对传感器输出信号进行处理,最终得到CIE L*a*b*色度值.将此颜色检测系统应用于胡萝卜不同干燥方式下的颜色检测,得出结论:热泵干燥比热风干燥对物料色泽的影响较小,温度设置越高,色泽退化越严重.     

由两组元活度系数比计算体系的热力学性质

提出了由两组元活度系数比计算二元系、三元系热力学性质的新方法,并推广到三元以上的多元系。还给出了检查计算结果准确性的检验式。     

基于PC的颜色识别与匹配系统的设计

采用颜色传感器TCS230与单片机设计高精度颜色识别系统平台,对所测得的数据进行处理,转换成RGB（Red、Green、Blue）三种颜色光数值,通过LCD将经过处理后的数据显示出来;同时通过串口将测得的数据发送到上位机,在PC机上实现颜色的合成与识别,以提高TCS230传感器实际应用效果。     

二种蕨类植物凝集素的细胞凝集和抑菌活性比较

将分别从狗脊蕨、扇叶铁线蕨叶片组织中提取得到的凝集素进行细胞凝集和抑菌活性比较.采用倍比稀释法在"V"型微量血凝板上进行凝集活性测定,采用琼脂平板法测定抑菌效果.结果发现二种凝集素均能有选择地凝集不同来源的动物血红细胞.狗脊蕨凝集素对鲫鱼红细胞的凝集活性最高达到29,扇叶铁线蕨凝集素对鸡红细胞的凝集活性最高达到210,对微藻细胞、细菌、酵母菌和肿瘤细胞的凝集具有特异性,对二种植物病原菌及细菌的抑制活性存在特异性.     

Minimum speed limit for ocean ridge magmatism from 210Pb-226Ra-230Th disequilibria

Although 70 per cent of global crustal magmatism occurs at mid-ocean ridges-where the heat budget controls crustal structure, hydrothermal activity and a vibrant biosphere-the tempo of magmatic inputs in these regions remains poorly understood. Such timescales can be assessed, however, with natural radioactive-decay-chain nuclides, because chemical disruption to secular equilibrium systems initiates parent-daughter disequilibria, which re-equilibrate by the shorter half-life in a pair. Here we use 210Pb-226Ra-230Th radioactive disequilibria and other geochemical attributes in oceanic basalts less than 20 years old to infer that melts of the Earth's mantle can be transported, accumulated and erupted in a few decades. This implies that magmatic conditions can fluctuate rapidly at ridge volcanoes. 210Pb deficits of up to 15 per cent relative to 226Ra occur in normal mid-ocean ridge basalts, with the largest deficits in the most magnesium-rich lavas. The 22-year half-life of 210Pb requires very recent fractionation of these two uranium-series nuclides. Relationships between 210Pb-deficits, (226Ra/230Th) activity ratios and compatible trace-element ratios preclude crustal-magma differentiation or daughter-isotope degassing as the main causes for the signal. A mantle-melting model can simulate observed disequilibria but preservation requires a subsequent mechanism to transport melt rapidly. The likelihood of magmatic disequilibria occurring before melt enters shallow crustal magma bodies also limits differentiation and heat replenishment timescales to decades at the localities studied.     

痛风舒片微生物限度检查方法有效性验证试验研究

以建立痛风舒片的微生物限度检查方法为目的。采用500 r min-1离心5min低速离心沉淀处理供试液与平皿稀释法联用测定细菌数;用平皿稀释法测定霉菌、酵母菌数;采用常规方法进行控制菌大肠埃希菌、大肠菌群检查。结果:样品对白色念珠菌有一定抑菌活性、对黑曲霉未显示抑菌作用;对细菌有较强抗菌活性;采用500r min-1离心5min低速离心沉淀处理供试液与平皿稀释法联用,金黄色葡萄球菌、枯草芽孢杆菌、大肠埃希菌活菌计数回收均可达到70%以上,并通过3个批号样品细菌计数有效性验证试验说明该法可有效消除药物对试验菌的抗菌作用。结论:建立的方法可有效的控制药品质量,准确可靠。     

汽车热交换器用铝合金钎焊带包覆率范围的确定

设计并制备了几种不同包覆率的３层复合铝合金钎焊带材,检测了每种带材在正常钎焊条件下的抗下垂性能,从铝合金钎焊带抗下垂的能力和填充缝隙的能力２个方面对包覆率的选择进行了分析与讨论,以厚度为０．１６ｍｍ的Ａ４３４３／Ａ３００３／Ａ４３４３铝合金钎焊带为例,得出其最佳包覆率范围是１０％～１６％．该方法可推广到其它厚度和材质的铝合金钎焊带中,确定它们的最佳包覆率范围．     

喙尾琵琶甲抗菌活性的研究

目的:观察喙尾琵琶甲乙醇提取物对耐甲氧西林金黄色葡萄球菌(MRSA)的体外抑菌活性.方法:采用试管稀释法测定喙尾琵琶甲乙醇提取物对5株临床分离的MRSA菌株的最低抑菌浓度(MIC)和最低杀菌浓度(MBC),初步判断其抑菌效果.结果:喙尾琵琶甲乙醇提取物对5株MRSA的MIC值为0.98～1.95 mg/mL,MBC值为3.9～7.8 mg/mL.结论:喙尾琵琶甲乙醇提取物具有良好的体外抑菌活性.