内皮素放射免疫测定的临床应用

内皮素(Endothe lin, ET)是日本学者1988年从猪的主动脉内皮细胞分离纯化的生物活性肽,以后在人的血管内皮细胞和血液中也发现了这种物质.通过对内源性物质的研究,有人提出了血管内皮是循环内分泌器官的新论点[1].人的ET有三种基因表达,即ET-1、ET-2、ET-3;它们都由21个氨基酸组成,具有两对二硫基键,其中ET-1的活性最强.ET的半衰期约1h,由肺、肝、平滑肌细胞和肾脏清除.     

涉核手套箱除尘去污方法概述

针对涉核手套箱内粉尘颗粒物的清洁去除,简要概述了包括溶剂擦拭法、粘附去污法和微型手持式吸尘器法等在内的几种简易的除尘去污方法,并根据去污实践经验分析了各种除尘方法的优缺点,对不同去污方法的适用场景提出了一些建议。     

转铁蛋白放射免疫分析法的建立及其初步应用

现已建立的转铁蛋白放射免疫分析法具有较高的灵敏度与特异性，结果稳定。标准曲线及标本的定量测量值重复性好；血清标本的批内ＣＶ＝１．８０％（ｎ＝１４），批间ＣＶ＝９．９４％（ｎ＝１０）；回收率高、中、低浓度平均为１０２．９１％；可测范围为７．８－５００μｇ／ｌ。所检测的血清、尿和唾液的正常值分别为３．０３±０．６６ｇ／ｌ（Ｘ±Ｓ）；１９８±９８μｇ／ｌ；５５７．８９±２０６．３２μｇ／ｌ。肾功能异常者     

一种确定放射性烟羽边界的新方法

根据航空γ场理论中Z量板等相关理论,提出了一种新型的放射性烟羽边界确定方法;并依据介质互换原理,在地面上利用矿体模型模拟烟羽(空气介质互换成河沙介质),进行实验模拟.实验结果表明,在实验室模拟情况下,空中异常半值点宽度从410 m变化到602 m,通过介质互换后用Z量板计算出的烟羽宽度与理论值之间的相对偏差在6.4%–8.9%范围内,误差较小,验证了此Z量板正确、有效,可用于实际航空测定放射性烟羽边界.     

Investigation of a facile plasma-driven method for in situ cleaning of metal-based contamination

Self-cleaning of tin contaminants was realized utilizing a self-driven hydrogen plasma.Cleaning rates of 0.7-6 nm min^-1 were achieved for removal of discontinuous tin particles at different powers.The analysis of topography and cross-sectional morphology revealed that the removal of tin particles was achieved through top-down cleaning with hydrogen plasma,where the upper part of spherical tin particles was always more intensely cleaned under the synergistic effect of hydrogen atoms an...     

稀有气体同位素样品取样及分析方法改进

根据渗透性、释气性、密封性特征,不锈钢、紫铜适合作为气体、水稀有气体同位素样品取样容器材料,尽量避免使用工艺玻璃容器,特别是不能使用石英玻璃容器。重晶石、黄铜矿、黄铁矿等硫酸盐和硫化物是良好的研究单矿物包裹体稀有气体同位素组成特征的实验对象,也可以根据矿床类型选择适当的单矿物,粒度一般为20~40目,质量2 g左右。铜管冷焊法是水样品取样一种比较可靠的新方法,其特点是具有极低的漏率。取样体积一般为50 mL,可以实现稀有气体同位素组成与含量的测定,为水中溶解性稀有气体同位素示踪提供了有力支撑。水中气泡气体取样采用正压吹扫法收集气体,该方法操作方便,易收集气体,一个大气压条件下,取样体积为50 mL。不锈钢管、紫铜管等金属材料的使用,可保证样品在相对较长时间保存过程中避免大气的污染。简述了包裹体、水、气体三类样品稀有气体同位素组成分析主要原理和流程。     

A rapid-detection method for radioactive cesium in the air

We propose a method of rapidly detecting radioactive cesium floating in the air for the purpose of alerting people active in the ‘difficult-to-return zone’ of Fukushima to changes in airborne radioactivity. With this purpose in mind, we set requirement specifications and created a new system concept. The targeted detection limit was 30 Bq/m³ and the mandatory level of measurement time was 48 min with a target level of 12 min, and these periods are 10 times faster than those of conventional air monitors. The system consists of a conventional gamma-spectrometer with a novel shaped shield. The targeted peak region of the measured energy spectrum is analyzed. After the basic design and confirmation of feasibility, we perform some experiments in the normal environment of Yokohama city and the difficult-to-return zone of Fukushima. Using the results, we conducted the design improvement and performance evaluation. As a result, the system performance is found to satisfy requirements. We thus conclude that this system is a promising candidate for rapid detection of airborne radioactivity in the difficult-to-return zone of Fukushima.     

Supercritical water heat transfer in vertical tubes: A look-up table

A new procedure for the prediction of wall temperatures in vertical tubes has been established in the framework of the development of the High Performance Light Water Reactor (HPLWR). The prediction of the wall temperature is accomplished by a look-up table for heat transfer in supercritical water. The look-up table lists the wall temperatures as a function of mass flux, heat flux, pressure, tube diameter, and bulk enthalpy. Based on an extended literature survey, experimental data for different conditions of upward flows in vertical smooth tubes are selected. To exclude data which exhibited local, buoyancy driven effects, a criterion of Jackson for deterioration of heat transfer is used to remove these data from further processing. An interpolation method is applied to assemble the tabulated grid points, based on published correlations for heat transfer in supercritical water. The look-up table covers a mass flux range of 700–3500 kg/m² s, a heat flux range of 300–1600 kW/m², a pressure range of 22.5–25 MPa, a diameter range of 8–20 mm and a bulk enthalpy range of 1200–2700 kJ/kg. Extreme combinations which required extrapolation of the data are excluded. The accuracy of the table in the vicinity of the pseudo-critical point is significantly higher than published correlations.     

用放射性核束进行弹性散射实验的一种角分布归一化方法

介绍了放射性核束弹性散射实验中测量的角分布进行归一化的方法。由于有限的测量角区及放射性核束有较大的发散度,采用了逐个事件计算的方法,在探测器空间分布区域用事先产生的一系列点构成的数据库模拟探测器边界,对这些点进行坐标转换,再进行选择判断,得到每个事件的几何探测效率。通过每个事件的几何探测效率推算到整个空间,得到实际的角分布。     

A new method for estimating heat flux in superheater and reheater tubes

In this paper a procedure on how to estimate the heat flux in superheater and reheater tubes utilizing the empirical formula and the finite element modeling is proposed. An iterative procedure consisting of empirical formulae and numerical simulation is used to determine heat flux as both temperature and scale thickness increase over period of time. Estimation results of the heat flux over period of time for two different design temperatures of the steam and different heat transfer parameters are presented.     

A simplified method for heat transfer prediction of supercritical fluids in circular tubes

This paper presents a new method for heat transfer prediction in supercritical fluids. Emphasis is put on the simplicity of the correlation structure, its explicit coupling with physical phenomena and the selection criteria of the test data. Assessment of qualitative behaviour of heat transfer is carried out based on existing test data and the experience gathered in the open literature. A single dimensionless number, the acceleration number, is introduced to correct the deviation of heat transfer of supercritical fluids from that of conventional fluids. The new correlation structure excludes any direct dependence of the heat transfer coefficient on the wall surface temperature, and eliminates possible numerical instability. The uncertainty analysis of the test data provides information about the sources and the levels of uncertainties of various parameters, and is strongly required for the selection of both the dimensionless parameters implemented into the heat transfer correlation and the test data for the derivation of correlations. Detailed assessment shows that the new correlation gives reasonable prediction accuracy over a wide parameter range and is also capable of predicting heat transfer behaviour in the heat transfer deterioration region.     

A hybrid method to generate few-group cross sections for fast reactor analysis

The accuracy of fast reactor core calculation is usually determined by the accuracy of self-shielded few-group cross sections. To further improve the accuracy of cross section generation, a hybrid method is proposed. In the hybrid method, the Monte-Carlo method is used to deal with the resonance effect in both the resolved and unresolved resonance range. The self-shielded ultrafine-group total, fission and elastic scattering cross sections are tallied by the Monte-Carlo method. The scattering transfer matrices are then generated in a synthesis way by using the tallied elastic scattering cross sections and a problem-independent elastic scattering function. The angular flux moments for the group condensation are calculated in an explicit deterministic way. Several tests are done to verify the hybrid method. The results show that the hybrid method avoids the disadvantages of both the traditional deterministic method and the pure Monte-Carlo method. It is a more accurate method to generate the few-group cross sections for fast reactor cores.