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.     

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).     

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.     

New experimental measurement of natSe(n, γ) cross section between 1 eV to 1 keV at the CSNS Back-n facility

The ⁷⁴Se is one of 35 p-nuclei, and ⁸²Se is a r-process only nucleus, and their (n, γ) cross sections are vital input parameters for nuclear astrophysics reaction network calculations. The neutron capture cross section in the resonance range of isotopes and even natural selenium samples has not been measured. Prompt γ-rays originating from neutron-induced capture events were detected by four C₆D₆ liquid scintillator detectors at the Back-n facility of China Spallation Neutron Source (CSNS). The pulse height weighting technique (PHWT) was used to analyze the data in the 1 eV to 100 keV region. The deduced neutron capture cross section was compared with ENDF/B-VIII.0, JEFF-3.2, and JENDL-4.0, and some differences were found. Resonance parameters were extracted by the R-matrix code SAMMY in the 1 eV-1 keV region. All the cross sections of ^natSe and resonance parameters are given in the datasets. The datasets are openly available at http://www.doi.org/10.11922/sciencedb.j00113.00019.     

2D/3D ZnIn2S4/TiO2复合物的原位构筑及其提高的光催化性能

通过高温煅烧和油浴的方法构筑二维/三维(2D/3D) ZnIn₂S₄/TiO₂异质结, 应用于光催化降解罗丹明B (RhB)和四环素(TC), 来研究异质结的构筑对TiO₂可见光响应范围和光生载流子对分离效率的影响. 结果表明, TiO₂维持了MOFs的形貌, 显示窄的可见光响应范围和高的光生电荷复合率, 与ZnIn₂S₄纳米片复合后, TiO₂的比表面积增大, 光催化活性位点增多. 带隙宽度也由TiO₂的3.23 eV减小到ZnIn₂S₄/TiO₂-II的2.52 eV, 从而获得了更宽的可见光响应范围. 能带结构表明ZnIn₂S₄/TiO₂是type II型异质结, 提高了光生载流子对的分离与转移效率. 在可见光照射下, ZnIn₂S₄/TiO₂-II显示了最高的RhB光催化降解效率(93%), 分别是TiO₂和ZnIn₂S₄的18和2倍. 同时, ZnIn₂S₄/TiO₂-II也显示出比TiO₂和ZnIn₂S₄更高的TC降解效率(90%). 循环实验表明ZnIn₂S₄/TiO₂-II能保持良好的稳定性, 经5次循环实验后仍能降解83%的RhB. 研究表明基于MOFs衍生的TiO₂构筑2D/3D ZnIn₂S₄/TiO₂异质结是提高TiO₂光催化性能的一条有效途径.     

EHP引发AM/DMMC反相微乳液聚合的研究

以油酸失水山梨醇酯Span80和壬基酚聚氧乙烯醚OP-10为乳化剂，白油为连续介质，过氧化二碳酸（2-乙基已酯）（EHP）为引发剂，进行丙烯酰胺/（2-甲基丙烯酰氧乙基）三甲基氯化铵（AM/DMMC）反相微乳液共聚合反应。研究了ωM=0.25-0.50范围内单体总浓度[M]、引发剂浓度[I]、乳化剂浓度[E]对聚合速率Rp和共聚物分子量M^-V的影响，得到Rp∝[M]^2.47[I]^0.76[E]^0.19,M^-v∝[M]^2.05[I]^-0.37[E]^-0.47。测定了AM/DMMC反相微乳液共聚合中单体的竞聚率，得到rAM=0.44,rDMMC=1.31。     

高效阴离子交换色谱-电化学法测定酱油中的氨基酸

采用高效阴离子交换色谱-电化学检测器分离并测定了18种常见氨基酸. 实验首先对酱油样品进行了简单前处理, 然后以一定浓度的NaOH和NaAc溶液为淋洗液, 选择合适的梯度淋洗条件, 使18种氨基酸在阴离子交换色谱柱上实现良好地分离, 并用脉冲安培检测器进行了测定. 氨基酸的检出限为1.7～20.0 μg/L, 样品加标回收率在85%～108%范围内. 方法灵敏度高, 操作简单, 重现性好, 不需要繁琐的柱前或柱后衍生操作. 已应用到生抽和老抽酱油调味料产品中氨基酸的测定.     

配位氧原子对7—氯—4—喹啉醇结构单元电子结构的影响

7-氯-4-喹啉醇氮氧化合物(Ⅰ)已被临床证明是一种抗癌新药,而7-氯-4-喹啉醇(Ⅱ)则不具有抗癌活性,二者在结构上只差1个配位氧原子,本文试图通过电子结构的比较分析阐明配位氧原子引起的7-氯-4-喹啉醇结构单元的电子结构变化,MINDO/3构型优化计算表明,化合物Ⅰ、Ⅱ皆为平面结构的几何构型,在此基础上进行了INDO/1+CI计算。     

高效阴离子交换色谱-脉冲安培检测器测定多种基体中痕量碘离的方法

建立了高效阴离子交换色谱脉冲安培检测器（HPAEC—PAD）测定碘离子的方法。以62．5mmol／LNaOH溶液作流动相，选用IonPac AS26型强亲水性阴离子交换分析柱，8min可以分离出碘离子，方法的检出限为0．05μg/L（25μL进样，3倍信噪比），标准曲线的线性范围为0．5—2000μg／L（r=0．9998）。1．0、2．5和25μg/L的碘离子标准溶液各9次进样的相对标准偏差分别为3．8％、2．6％和2．8％。试验了9种常见阴离子、3种易极化阴离子以及3种电化学活性物质对碘离子测定的影响，结果表明，在所选用的色谱条件下上述各化合物均不干扰碘离子的测定。用所建立的方法测定了盐水、矿泉水、海水、芹菜汁和紫菜浸提液等样品中碘离子含量，加标回收率在83％-114％。该方法具有灵敏度高、干扰小和样品前处理简单等优点。