共查询到19条相似文献,搜索用时 390 毫秒
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高产率自动化合成2-18F-2-脱氧-D-葡萄糖 总被引:1,自引:0,他引:1
研究了2-18F-2-脱氧-D-葡萄糖(18F-FDG)的高产率自动化合成工艺.以三氟甘露糖为前体,采用"一锅法"和TRACERlab FXF-N自动化合成装置,在同一反应瓶中进行亲核氟化、氢氧化钠水解两步反应,然后用小柱中和分离纯化制备了18F-FDG注射液.18F-FDG的总合成时间约24 min,未经校正的放化产率约为60%,放化纯度大于99%.采用改进了的自动化工艺合成18F-FDG注射液,操作简便,可望成为18F-FDG较为实用的合成方法. 相似文献
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采用离子氮化技术制备得到一定厚度的氮化铀层,以不同能量的氩离子轰击考察氮化铀的辐照氧化行为,并与大气中的自然氧化行为进行对比,考察材料在辐照环境下的稳定性。结果表明,氮化铀表面经氩离子轰击后,表面形貌发生了改变;氩离子轰击氧化与大气中的自然氧化行为存在差异,离子轰击增强了氮化铀表面的氧化程度,但其对氧化行为的影响主要在浅表面,大气氧化的氮化铀氧化层更厚;随着氩离子轰击能量的增加,表面氧化物含量及氧化层深度显著增加。总体而言,氩离子辐照对氮化铀层的影响随深度的增加而减弱,并不影响氮化铀的整体稳定性。 相似文献
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简便、快速自动化合成肿瘤显像剂18F-氟代乙酸盐和1-H-1-(3-18F-2-羟基丙基)-2-18F-硝基咪唑 总被引:1,自引:0,他引:1
用"一锅法"和TRACERlab FXF-N自动化合成仪系统合成了18F-氟代乙酸盐(18F-FAC)和1-H-1-(3-18F-2-羟基丙基)-2-硝基咪唑(18F-FMISO).以溴代乙酸苄酯为前体,在同一反应瓶中经亲核氟化、NaOH水解两步反应及Sep Pak小柱分离纯化制备了18F-FAC注射液,总合成时间小于40 min,未经校正的放化产率和放化纯度分别大于45%和99%.以1-(2'-硝基-1'-咪唑基)-2-O-四氢吡喃基-3-O-甲苯磺酰基丙二醇为原料,用类似方法制备了18F-FMISO注射液,总合成时间小于40min,未经校正的放化产率和放化纯度分别大于40%和95%.采用"一锅法"自动化合成18F-FAC和18F-FMISO注射液,操作简便,该工艺可用制备2-18F-2-脱氧-D-葡萄糖(18F-FDG)的全自动化合成模块来制备18F-FAC和18F-FMISO注射液. 相似文献
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分别以CCl_(4)和HCl气体作为氯化试剂,进行了铀氧化物(主要为U_(3)O_(8))的氯化机理和各影响因素研究。以CCl_(4)为氯化试剂对U_(3)O_(8)粉末进行氯化,通过热重分析研究了氯化反应过程的机理及动力学行为,氯化产物主要为UCl_(4)。同时研究了CCl_(4)对不同种类和形态铀氧化物的氯化,UO_(2)芯块由于结构致密很难进行氯化,UO_(2)粉末和UO_(3)粉末很容易被CCl_(4)氯化,产物分别为UCl_(4)和UCl_(6)。以HCl气体为氯化试剂对LiCl-KCl熔盐中的U_(3)O_(8)粉末进行氯化,研究了反应温度、氯化时间、HCl气体流速、U_(3)O_(8)粉末投料量以及铀氧化物种类和形态的影响。结果表明,提高反应温度、延长反应时间、提高HCl气体流速,有利于氯化率的提高。推荐HCl气体氯化U_(3)O_(8)粉末的工艺参数为:氯化反应温度为500℃、HCl气体流速为0.6 L/min。 相似文献
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研究了在水溶液体系中采用电沉积法制备铀靶的方法。以0.15mol/L草酸铵为电解液,铂丝为电极,通过考察阴极处理工艺、电流密度、电沉积时间、pH、温度、搅拌速度、镀液中UO2(NO3)2浓度等对电沉积效率及镀层质量的影响,确定了制备电沉积铀靶的最佳工艺参数,其中,沉积效率通过紫外分光光度法测得。在pH=2~3、电流密度60mA/cm2、保持温度60℃、镀液中UO2(NO3)2浓度约1.67mg/mL时沉积效率可达约98%。采用红外光谱、X射线能谱和扫描电镜等对铀沉积层进行了测试。结果显示,铀以水合聚合物的形式存在,可能的结构为[UO2(H2O)4-O-UO2(H2O)4-O],铀的沉积层的纯度较高,除检测到铀(65.35%)、氧(27.38%)、碳(5.46%)和铂(1.81%)外未引入其他杂质,镀层表面平整、致密,与衬底结合牢固。单次铀的电沉积层厚度可达6mg/cm2,采用高温烧结后重复电镀的方法可将电沉积铀的密度提高到6~8mg/cm2。 相似文献
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采用共沉淀工艺制得钍铀共沉淀物(AUTh C),AUTh C经分解还原得到(Th,U)O2+x粉末。采用差热-热重分析仪分析AUTh C分解过程,多分子层吸附理论(BET)法测定(Th,U)O2+x粉末比表面积。研究p H值、氨水加入量等共沉淀反应条件对钍铀共沉淀反应影响,以及无水乙醇处理AUTh C对(Th,U)O2+x粉末比表面积影响。实验结果表明:缓慢加入碳酸铵使p H值为5.5时,钍铀均具有较高沉淀率。加入氨水使p H升至7.5以上时,能明显提高钍铀共沉淀性能,母液中残余铀浓度为89 mg/L,残余钍浓度为105 mg/L。使用无水乙醇处理AUTh C能防止分解过程中(Th,U)O2+x粉末出现硬团聚;分解终点温度为600℃下保温2 h,(Th,U)O2+x粉末比表面积达15 m2/g。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(9):521-527
Uranium nitride and uranium carbonitride fuel pellets were prepared for irradiation in the Japan Material Testing Reactor. The pellets are 6.9 mm in diameter and 7 mm long, and are of natural and 5% enriched uranium. Uranium nitride powder was prepared from uranium metal via hydride and higher nitride. Uranium carbide powder was prepared from uranium metal by hydriding and then reacting with propane. The lowest possible reaction temperatures were selected to obtain fine and reactive powders. Uranium nitride and mixed powders of different ratios (UC: UN = 1: 3, 1:1 and 3: 1) were cold pressed without binder. Sintering was carried out in a tungsten crucible in vacuum (10~4 mmHg) for 2 hr at 1,900°–2,000°C. The density of the pellets obtained was in the range of 90~95% of the theoretical value with an oxygen content of 1,300~2,100 ppm. No second phase, such as metallic uranium, were observed in the specimens, either by metallography or X-ray diffraction. These pellets of unexpectedly high density without second phase must have been obtained thanks to the good powder characteristics combined with proper sintering conditions. The compositions of uranium carbonitride pellets were found to be slightly nitrogen deficient, compared with the reactants. 相似文献
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Young.-Woo Lee Ho Jin Ryu Jae Won Lee Jung Won Lee Geun Il Park 《Journal of Nuclear Materials》2009,392(2):171-175
Nitration reaction of a spent nuclear oxide fuel through a carbothermic reduction and the change in thermal conductivity of the resultant nitride specimens were investigated by a simulated fuel technique for use in nitride fuel re-fabrication from spent oxide fuel. The simulated spent oxide fuel was formed by compacting and sintering a powder mixture of UO2 and stable oxide fission product impurities. It was pulverized by a 3-cycle successive oxidation-reduction treatment and converted into nitride pellet specimens through the carbothermic reduction. The rate of the nitration reaction of the simulated spent oxide fuel was decreased due to the fission product impurities when compared with pure uranium dioxide. The amount of Ba and Sr in the simulated spent oxide fuel was considerably reduced after the nitride fuel re-fabrication. The thermal conductivity of the nitride pellet specimen in the range 295-373 K was lower than that of the pure uranium nitride but higher than the simulated spent oxide fuel containing fission product impurities. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(5):432-442
Dissolution of UO2 crucibles by molten Zircaloy-4 (Zry) was investigated in the temperature range of 2,223-2,373 K and for specimens having UO2/Zry mole ratios between 7 and 18.2. The uranium concentration in the Zry melt rapidly increased during initial reaction time and approached saturated values, depending on reaction temperature and UO2/Zry mole ratio. Kinetics of uranium concentration increase in the melt was analyzed based on a natural convection mass transfer model that takes into account the change of contact surface area/melt volume ratio with reaction time. The saturated uranium concentration in the Zry melt was inversely proportional to the U02/Zry mole ratio. An empirical correlation of saturated uranium concentration in the Zry melt was obtained as a function of UO2/Zry mole ratios and reaction temperature. This study of the empirical correlation was intended to estimate maximum UO2 fuel dissolution by molten Zry cladding during severe fuel damage accidents for three different reactor type fuels. 相似文献
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Ultra-fine aluminum nitride has been synthesized by the evaporation of aluminum powder at atmospheric-pressure nitrogen plasma in a hot-wall reactor.The average size of aluminum nitride particle is 0.11μm measured by scanning electric mirror(SEM),and the purity is at least over90% evaluated by X-Ray diffraction(XRD).The conversion of Al powder to aluminum nitride is strongly depended on the injection of NH3.Typical experimental parameters such as the feed rate of raw material,the flow rate of ammonia and the position of injecting aluminum powder into the reactor are given. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(2):60-64
A study was made of UN preparation by two-step reactions with UCl4, Al and N2 gas. In the first step, an intermediate uranium nitride with an N/U ratio of 1.68 resulted from the reaction of UCl4 with A1 under constant flow of N2 at reaction temperatures higher than 800°C. The X-ray pattern of the intermediate nitride did not correspond to any previously known uranium nitride. A maximum conversion efficiency of about 70% was obtained at temperatures between 800° and 1,000°G for the first reaction. In the second reaction, the intermediate nitride was heat treated under vacuum. To obtain single phase UN from the intermediate nitride, the heat treatment required a temperature of at least 1,100°C, at which the minimum holding time was 60 min. 相似文献
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为获取壳层O/U比约为2.25而芯部仍为UO2的预氧化活性粉末以进行UO2芯块的低温烧结试验,研究了UO2粉末在513 K下于静态空气中的氧化机制和动力学。结果表明:UO2粉末在513 K下氧化,可分为氧化前期和氧化后期;UO2粉末氧化后期绝对增重比率极限为0.489%;氧化前期反应速率受界面化学反应控制,氧化后期反应速率受扩散控制;氧化前期,UO2粉末氧化属于缩核模型,UO2单颗粒单位面积上氧化质量的增加量解析式为Dw/Sn=0.104 1t-2.146 67,氧化速率常数kc=3.49×106exp(-73 919.39/RT)。 相似文献
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CO对金属铀表面氧化层影响研究 总被引:9,自引:5,他引:9
用X射线光电子能谱(XPS)和气相色谱(GC)分析研究了CO对金属铀表面氧化层的影响。CO在表面氧化层上的吸附反应导致了U4f峰向低结合能方向位移,氧化物中氧含量减少,原子比(O/U)比值下降了7.2%。体系中CO2体积分数增大11.0%。研究结果表明,CO气氛可抑制金属铀表面的进一步氧化。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(8):638-645
Synthetic conditions of PuN from carbothermic reduction of PuO2 has been studied in a mixed 8%H2+92%N2 stream at a temperature range of 1,270–1,680°C. In the course of both reactions of the carbothermic synthesis of PuN from PuO2 and the hydrogenation of C, the vaporization loss of Pu was observed. It increased with temperature in the temperature range of 1,350–1,450°C, and reached to a constant value 1.3% of total Pu in the temperature range of 1,450–1,680°C, at which PuN was synthesized at a reaction rate of high enough. The minimum mixing ratio (C/PuO2, mole ratio) for the formation of high purity PuN depends on temperature. The value is 2.15 for 1,620°C and 2.35 for 1,680°C. The oxygen and carbon impurities in the PuN obtained were found to be 0.095–0.028 and 0.17–0.012w/0, respectively. 相似文献