Three-dimensional elastic recoil detection analysis of hydrogen in materials for use in the Yucca Mountain nuclear waste repository

An original system has been developed capable of performing three-dimensional Energy Recoil Detection Analysis (ERDA) of hydrogen in materials with scanned and finely focused heavy-ion beams. The technique is being used at the Lawrence Livermore National Laborotory Multi-user Tandem Laboratory to measure the hydrogen content in materials under consideration for use in the Yucca Mountain nuclear waste repository. From the measurement of hydrogen concentration profiles we can extrapolate reaction rates. A critical problem is the rate of dissolution of the glass being used. The HI-ERDA (Heavy Ion-ERDA) technique can provide this information which is needed in order to predict the overall rate of nuclear waste glass degradation in a waste repository. The technique is calibrated using a silicon wafer implanted with a known concentration of hydrogen. The sample is illuminated by a ³⁵Cl ion beam that is micro-scanned across the sample. From these measurements we reconstruct three dimensional profiles of hydrogen content which can then be used to obtain spatially-resolved hydrogen depth profiles.     

外周血淋巴细胞M受体反应性的测定

从全血中分出淋巴细胞，在含钙Ｈａｎｋｓ’液或含磷酸二酯酶抑制剂的缓冲液中孵育，加Ｃａｒｂａｃｈｏｌ能使细胞内ｃＧＭＰ含量增高６６％－８０％，这种升高可被阿托品阻断，说明ｃＧＭＰ的增高是由Ｍ受体介导的特异性反应。据此建立了一种反映Ｍ受体ＣＧＭＰ系统功能状态的方法并对孵育和反应条件作了探讨，初步实验结果表明老年大鼠淋巴细胞ＣＧＭＰ基础含量显著低于青年大鼠，由ＣａｒｂａｃｈｏｌＧＩ起的ｃＧＭＰ升高反应也明显降低。     

Degradation of Microcystin-LR by Gas-Liquid Interfacial Discharge Plasma

In this study, we report on the degradation of microcystin-LR （MC-LR） by gas- liquid interracial discharge plasma. The influences of operation parameters such as average input voltage, electrode distance and gas flow rate are investigated. Experimental results indicate that the input voltage and gas flow rate have positive influences on MC-LR degradation, while the electrode distance has a negative one. After 6 min discharge with 25 kV average input voltage and 60 L/h air aerati by discharge both in on, the degradation rate of MC-LR achieves 75.3%. distilled water and MC-LR solution are measured H202 and 03 generated Moreover, an emission spectroscopy is used as an indicator of the processes that take place on the gas-liquid boundary and inside plasma. Varied types of radicals （O, .OH, CO, 03, etc.） are proved to be present in the gas phase during gas-liquid interfacial discharge.     

Fenton-UV照射法对超高浓度聚乙烯醇有机废液的降解效能

采用Fenton-紫外照射（Fenton-UV）联用工艺对核电厂超高浓度聚乙烯醇（PVA）有机废液进行处理,研究了PVA转化率、平均分子量、溶液黏度等随时间的变化规律。结果表明：对于50 g/L的PVA溶液,H₂O₂投加质量浓度为15 g/L,FeSO₄·7H₂O投加质量浓度为0.050 g/L,初始pH值为3,经过2 h Fenton反应和2 h UV照射（3 mW/cm²）之后,PVA转化率达到100%,溶液平均分子量从60 000~80 000 Da降低到1 000 Da以下,黏度降低到1.1 mPa·s,但总有机碳和化学需氧量（COD）变化不大。Fenton-UV法可作为预处理方法,前期Fenton阶段提高PVA的溶解度,增加反应溶液中的PVA含量,并进行初步降解和氧化;后期UV法进一步降解溶液中的PVA,有效降低其分子量和黏度,为后续处理提供有利条件,最终形成经济可行的超高浓度PVA有机废液处理工艺。     

Degradation of Acid Orange 7 in an Atmospheric-Pressure Plasma-Solution System(Gliding Discharge)

In this work,a plasma-solution system was applied to the degradation of Acid Orange 7(A07).The effects of initial concentration and type of feed gases(air,oxygen,nitrogen or argon) were studied.As the initial concentration increased from 100 mg/L to 160 mg/L,the discolouration rate of A07 decreased from 99.3%to 95.9%,whereas the COD removal rate decreased from 37.9%to 22.6%.Air provided the best discolouration and COD removal rates(99.3%and 37.9%,respectively).In the presence of a zero-valent iron(ZVI) catalyst,the A07 COD removal rate increased to 76.4%.The degradation products were analysed by a GC-MS,revealing that the degradation of the dye molecule was initiated through the cleavage of the-N=N- bond before finally being converted to organic acids.     

Dissolution and Solidification of Aluminum Capsule in Production of Mo-99 by Sublimation from Neutron-Irradiated UO2

A technique, based on the correlation analysis of signal pulses in time sequence, is proposed to determine the production rate of the pseudo multi-pulse in Geiger-Mueller (GM) counter. With a multi-channel scaler initiated by a signal pulse, subsequent pulses are recorded in sequence. The production of the multi-pulse increases the counting probability immediately after the initiation. By examining the deviation of the measured probability from the ideal counting probability, the production rate and the average lag time to produce the multi-pulse can be determined. By the use of the present technique, the production rate and the average lag time were obtained for the various GM tubes. These results indicate that the consumption of the quench gas results in a significant increase in the production rate but little variation in the lag time, and that the lag time strongly depends on the tube diameter.     

Evaluation on a double-chamber gas-liquid phase discharge reactor for benzene degradation

A double-chamber gas-liquid phase DBD reactor (GLDR), consisting of a gas-phase discharge chamber and a gas-liquid discharge chamber in series, was designed to enhance the degradation of benzene and the emission of NOx. The performance of the GLDR on discharge characteristics, reactive species production and benzene degradation was compared to that of the single-chamber gas phase DBD reactor (GPDR). The effects of discharge gap, applied voltage, initial benzene concentration, gas flow rate and solution conductivity on the degradation and energy yield of benzene in the GLDR were investigated. The GLDR presents a higher discharge power, higher benzene degradation and higher energy yield than that of the GPDR. NO₂ emission was remarkably inhibited in the GLDR, possibly due to the dissolution of NO₂ in water. The benzene degradation efficiency increased with the applied voltage, but decreased with the initial concentration, gas flow rate, and gas discharge gap, while the solution conductivity presented less influence on benzene degradation. The benzene degradation efficiency and the energy yield reached 61.11% and 1.45 g kWh^–1 at 4 mm total gas discharge gap, 15 kV applied voltage, 200 ppm benzene concentration, 0.2 L min⁻¹ gas flow rate and 721 μS cm⁻¹ water conductivity. The intermediates and byproducts during benzene degradation were detected by FT-IR, GC-MS and LC-MS primarily, and phenols, CO_x, and other aromatic substitutes, O₃, NO_x, etc, were determined as the main intermediates. According to these detected byproducts, a possible benzene degradation mechanism was proposed.     

一种基于薄塑料闪烁体探测器的定向剂量当量率监测仪研制

基于薄塑料闪烁体探测器,采用MC模拟优化了定向剂量当量率监测仪探头组合结构。研制的用于弱贯穿辐射监测的定向剂量当量率仪,在10 μSv/h～100 mSv/h范围内,相对固有误差＜± 6%;⁸⁵Kr的β辐射场中,-60°～60°范围内角度响应好于± 40%;β辐射平均能量在60 keV～800 keV内,能量响应变化在-24%～49%范围内;变异系数小于2%。实验测量结果表明,该定向剂量当量率仪辐射性能满足GB/T 4835.1—2012要求。     

γ射线对水溶液中赭曲霉毒素A降解效果的研究

为了探讨γ射线辐照对于水溶液中赭曲霉毒素A的降解效果,采用60Coγ射线辐照水溶液中的赭曲霉毒素A.用赭曲霉毒素A标准溶液确定高效液相色谱检测技术的线性关系和检出限,然后基于高效液相色谱检测技术研究辐照对水溶液中赭曲霉毒素A的降解效果.结果显示,水溶液中赭曲霉毒素A的降解率随着辐照剂量的增加而增加;在4kGy的辐照剂量...     

一种潜在5-HT1A脑受体显像剂99Tcm-Bicine/HYNIC-MPP2的制备及其生物性能

优化合成了含有1-(2-甲氧基苯基)哌嗪(MPP)结构的配体2-(4-(2-甲氧基苯基)哌嗪基)乙胺-6-叔丁基氧羰基肼基吡啶-3-甲酸(HYNIC-MPP2).在室温下以N,N-二(2-羟基乙基)氨基乙酸(Bicine)为共配体制备得到配合物~(99)Tc~m-Bicine/HYNIC-MPP2,其放射化学纯度大于95%,并且在6 h内保持稳定.脂水分配系数和电泳实验结果表明,该放射性标记配合物是水溶性和电中性的.正常小鼠体内生物分布实验结果表明,~(99)Tc~m-Bicine/HYNIC-MPP2有一定的脑摄取(注射后2 min时为0.31%ID/g).脑区域分布及抑制实验显示,该配合物在5-HT_(1A)受体含量丰富的海马组织有较高摄取(注射后2 min时为1.00%ID/g),而在受体含量低的小脑组织中摄取也低(注射后2 min时为0.63%ID/g).抑制后,海马摄取降低较多(注射后2 min时为0.42%ID/g),而小脑摄取则无明显变化.抑制前后海马/小脑比值分别为1.59和0.89.由此可见该标记配合物与5-HT_(1A)受体具有一定特异性结合,是一种新的潜在5-HT_(1A)受体显像剂.