溶胶-凝胶固相微萃取涂层及其在农药残留分析中的应用

利用溶胶-凝胶(sol-gel)技术制备固相微萃取(SPME)涂层材料.通过硅醇盐前驱体与涂层聚合物羟基硅油(OH-TSO)的水解共聚的方法,成功地制备了聚二甲基硅氧烷sol-gel 涂层的SPME 萃取头,并以农药的混合标准水溶液为研究对象,用直接-固相微萃取-气相色谱法(GC)对涂层的性能进行考察,制成的萃取头适用于多种农药残留的萃取分离分析.     

正硅酸锂陶瓷小球离线释氚实验研究

中国氦冷球床包层(CH HCSB TBM)初步采用Li₄SiO₄陶瓷小球作为氚增殖材料,实验研究了Li₄SiO₄陶瓷小球的中子辐照产氚性能。将冷冻成型法制备的Li₄SiO₄ 陶瓷小球置于反应堆中辐照100min,然后在离线释氚实验平台上进行退火行为研究。实验结果表明,在用He +1% H₂为载气,流速为100mL•min^-1,升温速率为5K•min^-1的实验条件下,氚气(HT+T₂)是Li₄SiO₄陶瓷小球的主要释氚形态,占总氚的70%左右(不包括自由氚中的氚气),在400℃~700℃范围内出现两次释氚峰;氚化水(HTO+T₂O)所占比例小于20%,主要在300℃~500℃的低温段进行释放;氚在800℃前基本释放完,小球退火后的残氚量小于1%。冷冻成型干燥法制备的Li₄SiO₄陶瓷小球在300℃~700℃范围内有较好的释氚性能,氚残留量低,在聚变堆固态氚增殖包层设计中具有一定应用价值。     

银/二氧化硅复合材料对硝酸钠红外吸收光谱特性影响

对海洋营养盐进行快速检测是海洋污染监控中的一项重要任务。测量了硝酸钠溶液蒸发过程中的红外光谱,发现表面增强红外光谱法在营养盐的快速检测中有重要的应用价值。采用Stober方法制备了二氧化硅纳米颗粒,然后采用银氨溶液与二氧化硅溶液混合的方法制备银/二氧化硅(Ag/SiO₂)复合材料,并利用扫描电镜(SEM)、X射线衍射(XRD)以及紫外-可见(UV-Visible)吸收光谱对其进行表征。研究了硝酸钠水溶液干燥过程中Ag/SiO₂复合材料对硝酸钠红外吸收光谱的影响,结果表明硝酸根反对称伸缩振动吸收峰的吸收强度得到增强,这可能来自Ag/SiO₂薄膜材料的界面效应。     

基于线性方程组数学分离模型建立光纤传感过程检测复方缬沙坦氢氯噻嗪片溶出度

基于线性方程组数学分离模型建立在线过程检测复方缬沙坦氢氯噻嗪片溶出度方法。分别扫描缬沙坦和氢氯噻嗪的紫外吸收光谱,两组分在最大吸收波长处完全重叠。根据朗伯比尔定律吸光度加和性原理,分别测定两组分在最大吸收波长处的吸光系数,建立线性方程组数学分离模型,采用光纤传感过程分析技术(FODT)检测缬沙坦氢氯噻嗪片的溶出度,并与HPLC法相比较。在规定的溶出介质中,两种成分同时实时测定,并且FODT累积溶出度与HPLC法相比较结果无显著性差异(p>0.05)。不同批次药物的溶出行为一致,说明制剂工艺稳定,均匀度好。溶出曲线显示缬沙坦溶出快于并高于氢氯噻嗪,且30 min时两组分的溶出度均大于80%符合美国药典规定。结果表明,应用线性方程组数学分离模型结合FODT法可实现复方缬沙坦氢氯噻嗪片中双组分溶出度的同时检测,并可提供双组分的溶出过程曲线和全部溶出数据,直观反映各组分在各溶出时段的快慢,为此药建立标准提供依据。与HPLC法单点数据相比优势明显,更有利于药品评价和抽验质量分析。     

利用同质异位素产额比提取对称能的近似方法

在修改的Fisher模型框架下, 利用同质异位素产额比和结合能方程中对称能系数与温度比率的关联, 可以提取对称能系数与温度的比值。 利用3种不同的近似方法得到了重离子核反应产生丰中子余核的对称能系数与温度比（a_sym/T）,并研究了相关物理量对a_sym/T的影响。结果表明, 库仑能对提取丰中子余核的a_sym/T影响较小,且参考核的选取对a_sym/T的提取也有一定的影响。 In the framework of the modified Fisher model, correlations between the symmetry energy coefficient in semi classical mass formula to temperature (a_sym/T) and the isobaric yield ratio in Heavy ion collisions are established. a_sym/Tof neutron rich fragments are extracted using these correlations. It is found that the Coulomb energy term has little effect on a_sym/T of fragments, while the reference isobars adopted have great influence on the extracted a sym/T of fragments.     

边界条件对非共沸混合工质有机朗肯循环的影响

有机朗肯循环是利用低温热源的有效措施之一,将非共沸混合工质应用于有机朗肯循环尚存在争论。从热力学角度研究了非共沸混合工质的选择与边界条件之间的关系,以典型的对称型混合工质R601a/R600和非对称型混合工质R245fa/R600a为例,以带内置热交换器的有机朗肯循环为研究对象,以系统净功最大化为目标,分析了冷凝泡点温度和冷却水温升固定时混合工质的最佳浓度及系统性能。研究结果表明不同边界条件的应用对非共沸混合工质的选择具有重大影响。当固定的冷凝泡点温度被采用时,非共沸混合工质的温度滑移现象会降低系统净功,当冷却水温升固定时,温度滑移的适当提高有利于系统净功的增加,但过高的温度滑移会降低系统净功。冷凝泡点温度等于冷却水初温和冷凝器节点温差之和时所对应的净功曲线对系统设计具备指导意义。     

Pairing-energy coefficients of neutron-rich fragments in spallation reactions

The ratio of pairing-energy coefficient to temperature(a_p/T)of neutron-rich fragments produced in spallation reactions has been investigated by adopting an isobaric yield ratio method deduced in the framework of a modified Fisher model.A series of spallation reactions,0.5A and 1A Ge V~(208)Pb+p,1A Ge V~(238)U+p,0.5A Ge V~(136)Xe+d,0.2A,0.5A and 1A Ge V~(136)Xe+p,and~(56)Fe+p with incident energy ranging from 0.3A to 1.5A Ge V,has been analysed.An obvious odd-even staggering is shown in the fragments with small neutron excess(I≡N-Z),and in the relatively small-A fragments which have large I.The values of a_p/T for the fragments,with I from 0 to36,have been found to be in a range from-4 to 4,and most values of a_p/T fall in the range from-1 to 1.It is suggested that a small pairing-energy coefficient should be considered in predicting the cross sections of fragments in spallation reactions.It is also concluded that the method proposed in this article is not good for fragments with A/A_s85%(where A_(s )is the mass number of the spallation system).     

碳纳米管负载纳米金-石墨烯量子点修饰电极电化学检测过氧化氢

采用过氧化氢刻蚀法制备石墨烯量子点(GQDs),再采用原位化学还原法制备金纳米粒子-石墨烯量子点纳米复合物(Au NPs-GQDs),最后以聚二甲基二烯丙基氯化铵(PDDA)为交联剂将上述纳米复合物组装于多壁碳纳米管表面,制得金纳米粒子-石墨烯量子点-PDDA-多壁碳纳米管复合材料(Au NPs-GQDsPDDA-MWCNTs)。通过荧光光谱法、紫外-可见吸收光谱法和透射电子显微镜对上述复合材料进行表征。采用滴涂法制得该复合材料修饰的玻碳电极,研究了过氧化氢在该电极上的电化学行为。结果表明:在石墨烯量子点、金纳米粒子和多壁碳纳米管三者的协同作用下,该电极对过氧化氢的电氧化表现出强的催化活性。在优化条件下,安培法检测H_2O_2的线性范围为2.0×10~(-8)~1.5×10~(-3)mol/L,检出限(3sb)为8.0×10~(-9)mol/L,灵敏度为61.6μA/(mmol·L~(-1))。     

Investigation of neutron induced reactions on ^23Na by using Talys1.4

The neutron induced reactions on ^23Na are investigated by using the Talys1.4 program. The calculated results for the ^23Na（n, 2n）22Na reaction are found to agree with the experimental results. The cross sections of the residues of the（n, n）,（n, γ）,（n, p）, and（n, np） channels in the reactions are presented, and at the same time, the neutron induced reactions on22 Ne are also investigated.     

Investigation of neutron induced reactions on ~(23)Na by using Talys 1.4

The neutron induced reactions on23 Na are investigated by using the Talys1.4 program. The calculated results for the23Na(n, 2n)22Na reaction are found to agree with the experimental results. The cross sections of the residues of the(n, n),(n, γ),(n, p), and(n, np) channels in the reactions are presented, and at the same time, the neutron induced reactions on22 Ne are also investigated.