高压充氘氚气体的金属系统研制

描述了建造高压充氘氚金属系统的基本过程.15 MPa时,系统漏率为(3.7～4.8)×10-4 Pa*L/s.经微球充气实验证实用该系统操作大量的氚(2.8×1014 Bq)是极其安全、可靠的.     

23-羟基白桦酸的碘标记及其在荷肝癌HepA肿瘤鼠体内的分布

采用双氧水法对23-羟基白桦酸进行131I标记;以硅胶纸为支持介质,V=氧甲烷∶V甲醇=9∶1为展开剂,测定标记率及标记物放化纯;ICR小鼠和荷肝癌HepA肿瘤鼠尾静脉注射131I-23-羟基白桦酸(0.74 MBq/只)后考察标记物的药代动力学性质及荷瘤鼠体内分布.结果显示,131I-23-羟基白桦酸标记率达98%,其放化纯在1、4、8 d分别为98.5%、97.3%、95.8%.131I-23-羟基白桦酸在正常小鼠体内血液清除较快,其药代动力学模型符合二室模型.注射后0.5 h荷肝癌HepA肿瘤鼠肝摄取最高(9.14%ID·g-1组织),其次为肾、血、脾、肠、肺、肿瘤,脑中分布最少,仅为0.28%ID·g-1组织;肿瘤/肌肉比值＞3.表明碘标23-羟基白桦酸标记率高,标记物稳定;碘标记物在荷肝癌HepA肿瘤鼠中的肿瘤靶向摄取提高2倍,可能是一新型增效的核素靶向治疗药物.     

大鼠长期饮用氚水的致癌效应研究

本文观察了S.D.大鼠长期(1.5年)饮用低浓度氚水后的肿瘤发生情况。实验分3组:对照组、1.11×10~5Bq/mL组和2.22×10~4Bq/mL组。结果表明,大鼠长期饮用氚水1.5年后,对照组、1.11×10~5Bq/mL 组和2.22×10~5Bq/mL 组的肿瘤发生率分别为22.5%、30.4%和56.0%,其中恶性肿瘤的发生率分别为7.5%、6.5%和34%。经 X~2检验,2.22×10~5Bq/mL 组的肿瘤发生率明显高于1.11×10~5Bq/mL组(p<0.05)和对照组(p<0.01),恶性肿瘤发生率也明显高于1.11×10~5Bq/mL 组(p<0.01)和对照组(p<0.01);2.22×10~5Bq/mL 组动物的肿瘤出现时间比1.11×10~5Bq/mL 组早200 d 左右;恶性肿瘤中以纤维肉瘤、腺癌为多见,其次为白血病和横纹肌肉瘤,良性肿瘤以纤维瘤和腺瘤多见。     

强流中子发生器运行期间氚污染调查

本文报道了14MeV 强流(3.3×10~(12)n/s)中子发生器运行期间空气中氚浓度的调查结果。各采样点空气中的氚浓度分别为:手套箱,8.9MBq/m~3;发生器大厅走道,6.6kBq/m~3;氘操作室,4.1kBq/m~3;尾气排放口,9.7×10~7Bq/m~3;发生器大厅外,98Bq/m~3。调查结果表明,发生器运行期间工作场所和居民区空气中的氚浓度有所增加,但均未超过国家防护标准中对工作人员和对公众的导出空气浓度(DAC)。     

在出生前以氚水照射致大鼠脑发育障碍的剂量效应关系研究

以脑组织中游离氨基酸含量为指标,观察出生前因氚水照射引起的大鼠脑发育障碍。实验用妊娠11d的大鼠经腹腔单次注入7.4×10~3—3.7×10~6Bq/ml(体水)放射性浓度的氚水。在仔鼠出生后18d将其开颅取出大脑。取一半脑组织用高效液相色谱(HPLC)测定脑组织中游离氨基酸含量。结果表明:受照仔鼠大脑组织中游离氨基酸含量随照射剂量增加而增多。在仔鼠总吸收剂量为0.0038—1.9Gy范围内,大脑组织中游离氨基酸含量增加的百分率与剂量对数值之间可拟合成直线回归方程Y=A+B lgD。     

饮用水中的放射性核素所造成的危险

本文对饮用水中放射性核素所造成的危险进行了评价。来自放射性核素的主要危险是自然产出的Ra、U和Rn。这些元素产出的平均水平为:~(226)Ra为1.11×10~(-2)—2.96×10~(-2)Bq/L,~(228)Ra为1.48×10~(-2)—3.7×10~(-2)Bq/L,天然铀为1.11×~(-2)—7.4×10~(-2)Bq/L,~(222)Rn为1.85—12.95Bq/L,~(210)pb为<0.41×10~(-2)Bq/L,     

人参皂甙20(S)-protopanaxadiol的氘、氚标记及其在A549细胞内的浓度

分别用钠硼氘、钠硼氚还原人参皂甙Rh1的活性形式20(S)-protopanaxadiol（aPPD）的氧化前体aPPD=O，制备氘、氚标记的aPPD。标记物经板层析（TLC）、质谱(MS)、核磁共振（NMR）分析鉴定，结果与标准品的测量数据一致；氚标记的aPPD放化纯度为98%，放射性比活度为7.64×1011Bq/g。将3H-aPPD作用于人肺腺癌A549细胞，检测不同时间细胞浆及细胞核中氚的活度，结果提示aPPD在A549细胞浆、核内均于24 h达到最高浓度，表明aPPD作为一个与甾体类激素结构相类似的药物，可以进入细胞甚至细胞核发挥药理作用     

利用γ-32P-ATP，51Cr研究蛋白激酶C对血管内皮细胞CD44表达及内皮粘附功能的影响

分别用钠硼氘、钠硼氚还原人参皂甙Rh1的活性形式20(S)-protopanaxadiol（aPPD）的氧化前体aPPD=O，制备氘、氚标记的aPPD。标记物经板层析（TLC）、质谱(MS)、核磁共振（NMR）分析鉴定，结果与标准品的测量数据一致；氚标记的aPPD放化纯度为98%，放射性比活度为7.64×1011Bq/g。将3H-aPPD作用于人肺腺癌A549细胞，检测不同时间细胞浆及细胞核中氚的活度，结果提示aPPD在A549细胞浆、核内均于24 h达到最高浓度，表明aPPD作为一个与甾体类激素结构相类似的药物，可以进入细胞甚至细胞核发挥药理作用。     

肝胆显像剂~(131)I(~(125)I)-CGT的制备、动物实验及临床应用

~(131)I(~(125)I)标记的胆酰甘氨酰酪氨酸(CGT)是一种新的肝胆显像剂。~(131)I-CGT药盒的组成为:CGT 1mg、氯胺-T 0.35mg、偏重亚硫酸钠8mg、~(131)I 3.7×10~7-7.4×10~7Bq。在应月时加5％NaHCO_3,注射液溶解,溶液呈澄清液,pH=7.4。~(131)I-CGT得率75—85％(符合药典~(131)I标记化合物的要求),放射化学纯度为95—98％。     

氚水在大鼠和小鼠体内的分布、代谢、转移及剂量估算

本文汇总报道了氚水在大鼠和小鼠体内的分布、代谢、转移及剂量估算研究结果:(1)氚在小鼠体液及各组织中按指数下降规律呈均匀分布;(2)非妊娠鼠总氚的第一生物半排期约2 d,孕鼠和泌乳鼠分别约1.6和1.7 d,氚在母鼠、孕鼠和泌乳鼠体内的代谢规律基本一致;(3)大鼠组织中的氚活度分布不均匀,第15天组织中的滞留活度约占第1天的9％左右。(4) 氚化小麦组大鼠组织内总氚和有机结合氚均明显高于氚水组;(5)氚水可通过受伤皮肤吸收进入体内,不同受伤程度的皮肤对氚的吸收率为切割伤>磨擦伤>烫伤>化学烧伤;(6)小鼠妊娠期和泌乳期母体内氚可通过不同途径转移给胎儿和仔鼠,转移系数在1.06～2.37之间;(7)小鼠母鼠、妊娠鼠和泌乳鼠总氚累积吸收剂量分别为8.5、6.7和7.1 mGy。     

我国东南沿海城市地下建筑氡浓度分布

为了解东南沿海城市地下建筑氡浓度的分布，用固体核径迹法(SSNTD’s)，分别在春、夏、冬3季对沿海7城市地下建筑室内氡浓度进行调查。结果表明，福州具有最高的平均氡浓度，上海的平均氡浓度最低。季节的变化对地下建筑室内氡浓度有影响，各城市氡浓度平均值夏季最高、冬季最低。各城市夏季氡浓度与该城市的年均值的比值与城市中各测点氡浓度之间的离散度有一定的相关性。夏季地下建筑室内氡浓度高的城市，它的平均氡浓度受某些具有高氡水平测点的影响大。     

Fusion Safety Studies in Russia in 1996

The paper seeks to provide a summary report of observations and results of some Russian fusion safety studies performed in 1996. Release of tritium and helium from neutron irradiated beryllium at relatively high neutron fluences has a burst nature. With the growth of the beryllium temperature-increase rate to 90 K/s, the temperature of tritium burst release decreases from 800 to 450–500°C and for helium decreases from 1200 to 500°C. Characterization of carbon and tungsten dust produced in experiments simulating plasma disruptions revealed that dust particle distribution of sizes for graphites and carbon fiber composites has a bimodal nature with maxima in the range of 0.01–0.03 and 2–4 m for composite UAM and in the range of 0.14–0.18 and 2–4 m for graphite MPG-8. Chemical reactivity of beryllium with air was studied as well. A mathematical model for beryllium weight gain under its chemical interaction with air at temperatures of 700–800°C as a function of beryllium porosity, temperature, and interaction duration was developed.     

Trends in computational intelligence in nuclear engineering

Several changes to the focus of Computational Intelligence in Nuclear Engineering have occurred in the past few years. With earlier activities focusing on the development of condition monitoring and diagnostic techniques for current nuclear power plants, recent activities have focused on the implementation of those methods and the development of methods for next generation plants and space reactors. These advanced techniques are expected to become increasingly important as current generation nuclear power plants have their licenses extended to 60 years and next generation reactors are being designed to operate for extended fuel cycles (up to 25 years), with less operator oversight, and especially for nuclear plants operating in severe environments such as space or ice-bound locations.     

Increase in internal friction in uranium with change in temperature

On the basis of the previously described increase in internal friction in uranium during heating, a semiquantitative evaluation was made of the dependence of increase in internal friction on the rate of heating, frequency and amplitude of vibrations. The results of the calculations agree satisfactorily with data obtained experimentally. A study was made of the effect of the initial state of the specimen on the increase in internal friction at the initial stages of heating.     

Temporal changes in vertical distribution of 137Cs in litter and soils in mixed deciduous forests in Fukushima,Japan

Downward migration of ¹³⁷Cs in soils was studied in three mixed deciduous forests c.a. 40 km northwest of the Fukushima Daiichi Nuclear power plant (FDNPP), Japan. We selected three different types of forest regarding to environmental condition such as slope inclinations and snow coverage conditions at the time of deposition. We examined temporal changes in the vertical distribution of ¹³⁷Cs from litter layers to 10 cm soil depth for two years (2.3 to 4.3 years after the FDNPP accident in 2011). At all three study sites, the ¹³⁷Cs in the litter layer had largely migrated to surface soil by 2013. After 2014, about 80% of the ¹³⁷Cs in forest soils (litter layer to 10 cm soil depth) remained within 0–5 cm soil layer. The vertical distribution had not changed substantially since 2014, suggesting that changes to the downward migration rates of ¹³⁷Cs in soils drastically decreased with time. In addition, small amounts of migrating ¹³⁷Cs could not be detected by the present method because there was a large spatial variation in the distribution of soil ¹³⁷Cs. The results showed similar patterns of soil ¹³⁷Cs distribution among the three study sites although there were differences in the environmental conditions.     

微机在核物理实验应用中的抗干扰问题

本文简单介绍了计算机在核物理技术应用中的各种噪声，并初步探讨了抑制噪声的方法。     

广东省进出口食品中的放射性检验

报道了广东省商检中心放射性检验室开展的广东进出口食品中的放射性检验工作。介绍了检验工作采用仪器的主要性能及应用;给出了分析测量方法和探测下限以及实验的质量保证措施,并给出了检验室测量的广东省几种食品中的放射性含量范围,测量结果与我国食品中放射性活度变化范围大体一致。     

Tritium concentrations in precipitation in Shanghai

Beamline BL17 U1 at Shanghai Synchrotron Radiation Facility is an energy-tunable macromolecular crystallography beamline that has been in user operation since 2009. Growing demand from the user community for a small beam and related experimental methods have motivated upgrades of the devices in the endstation.Minibeam modes have already been developed for operation. A self-integrated diffractometer reduces the sphere of confusion of the rotatory axis to 1μm. The new diffractometer is equipped with an upgraded on-axis viewing system that can improve the resolving power. Additionally,the area detector was also upgraded to the newest generation of detectors, the EIGER X 16 M, which can collect data at 133 Hz. After these upgrades, the endstation became virtually new. This paper covers the upgrade of the endstation devices and gives the first data collection results.     

2010年的美国铀矿业

2010年,美国铀矿总共施工7 209个钻孔,总进尺1 493 520 m;生产铀1 628.55t;铀矿业总支出费用为2.773亿美元,其中铀矿地勘费支出为3 450万美元,占铀矿业总费用的12.44％.铀矿地勘钻探费用为4 460万美元,占铀矿业总费用的16.08％.     

固体核径迹研究进展

介绍最近几年固体核径迹研究取得的主要进展，包括：径迹形成机制和探测方法研究固体核径迹在核物理、高能和相对论重离子核反应，原子物理、空间科学、宇宙射线探测、地学、测氡和核孔膜等领域的应用。