140AMeV 58,64Ni+9Be反应中同位旋标度规律的研究

利用反对称化的分子动力学（AMD）模型模拟140 AMeV 58,64Ni+9Be反应,并利用同位旋标度法研究两相似反应系统的△μ_n（p）/T随时间演化趋势。分析比较不同碰撞参数和不同反应系统间的△μ_n（p）/T随时间演化结果,结果表明碰撞参数对重核的对称能影响大,系统不对称度越大对对称能的影响越大,为间接研究激发核体系对称能系数的能量依赖提供了帮助。We have simulated the reactions 140 AMeV 58,64Ni+9Be by antisymmetric molecular dynamics model (AMD) and studied the evolution of △μ_n(p)/T with collision time from 20 fm/c to 1 000 fm/c. To study nuclear symmetry energy influencing factors, a comparative analysis has been proceed among theses results with different impact parameters and the difference reactions system. The results show that the impact parameters have a great influence on the symmetry energy of the heavy nucleus, and the greater the asymmerty degree of the system, the greater the influence on the symmetry energy. These results are helpful for the indirect study of the energy dependence of the symmetry energy coefficient of the excited nuclear system.     

堇青石蜂窝陶瓷载体上SAPO-34分子筛的原位合成

运用水热合成技术在孔密度为62cells/cm²的堇青石蜂窝陶瓷载体上原位合成了SAPO-34分子筛,并用XRD和SEM等技术对其进行了表征.结果表明,经过一次水热合成,堇青石蜂窝陶瓷载体的表面上可牢固均匀地生长一层厚度约为30μm的SAPO-34分子筛,而相应的载体增重约为15%～25%.改变合成条件还可使堇青石载体上同时生长SAPO-34和SAPO-5分子筛.此外,对SAPO-34分子筛在堇青石载体上的生长机理也作了初步探讨.     

脉冲微波辐照影响心肌细胞膜蛋白构象及其机制的研究

应用显微傅里叶变换红外光谱技术研究了脉冲微波辐照对心肌细胞膜蛋白质构象、功能的影响和相关分子机制。结果表明,辐照可对心肌细胞的细胞膜蛋白质结构产生明显影响。细胞膜脂质中—CH₂—、磷脂结构中CO、蛋白质酰胺Ⅰ,Ⅱ带的伸缩振动峰消失或位移。辐照后心肌细胞膜蛋白质二级结构也出现明显变化,α-螺旋和β-折叠结构减少,二级结构无序化程度增加。上述变化均与辐照剂量呈正相关。结果提示受脉冲微波辐照后,心肌细胞膜蛋白构象的完整性受损,膜稳定性及流动性下降,膜上多种生物活性结构被破坏,上述变化构成了细胞膜功能丧失、细胞形态和结构损伤、细胞凋亡等病理学效应的生物化学基础。文章首次从蛋白质构象角度阐述了微波辐照对心肌细胞膜损伤的分子病理机制。     

基于玻璃基底的TiO2自清洁减反射薄膜的研究

采用直流磁控溅射(DMS)技术和能量过滤磁控溅射(EFMS)技术在玻璃基底上制备了TiO2薄膜.用TFC膜系设计软件优化设计了单层和双层减反射薄膜,确定制备工艺参数,根据优化结果分别制备了TiO2构成的单层和双层薄膜.利用SEM、椭偏仪、接触角测定仪和光催化测试系统对薄膜进行了表征和测试.实验结果表明:优化设计的膜层都具有良好的减反射性能,单层和双层薄膜在400~800 nm的平均透射率分别为0.845和0.891.氙灯照射30 min后接触角从61.5°变为28°和8°,后者具有超亲水性.紫外光照下对RhB的降解速率分别为-0.0019 min-1和-0.0034 min-1,具有良好的自清洁性能.单层和双层TiO2薄膜具有自清洁和减反射性能.由高低折射率匹配组成的双层薄膜有较平滑的曲线,光催化降降解性能和亲水性较好.     

栅极热变形对离子推力器工作过程影响分析

栅极热变形是影响离子推力器性能和寿命的重要因素. 采用三维粒子方法对栅极系统等离子体输运过程进行模拟, 对比、分析栅极热变形前后栅极系统的电子返流限制、导流系数限制、离子通过率和发散角损失. 结果表明: 栅极热变形增大了屏栅离子通过率和推力器推力值, 并由于加速栅截止电流阈值的提高拓展了推力器工作电流区间, 但电子返流阈值的明显降低对栅极系统可靠工作造成了不利影响.     

CaCl_2添加对热解煤中汞析出规律影响的实验研究

在程序升温热解反应装置上,研究了低氯煤中添加不同氯含量(质量分数0.1%、0.3%、0.5%)的CaCl2对煤热解过程中汞析出规律的影响。实验结果表明,温度是影响汞析出的关键因素;随着氯添加量的增加,Hg2+析出比例呈上升趋势,且汞的最佳析出温度降低,汞的释放率也有所降低;随着热解气氛中O2比例的增加,Hg2+比例也略有增加;较高的升温速率能加快汞的释放,也能提高Hg2+的比例。低氯煤中添加氯化钙能够强化单质汞的氧化。     

Isospin dependence of projectile fragmentation and neutron-skin thickness of neutron-rich nuclei

By investigating the cross section distributions of fragments produced in the 140 A MeV ^40,48Ca+⁹Be and 1 A GeV ^124,136Xe+Pb reactions, the isospin dependence of projectile fragmentation in fragment production is studied. In the framework of the statistical abrasion-ablation model, the 1 A GeV ¹³⁶Xe+²⁰⁸Pb reaction is calculated. By adjusting the diffuseness parameter in neutron density distribution of ¹³⁶Xe, we find the isospin dependence of projectile fragmentation in fragment production is sensitive to the neutron-skin thickness of the projectile nucleus.     

强酸型离子交换树脂催化吸附制备Valienamine

以阿卡波糖为原料制备α-糖苷酶抑制剂Valienamine,通过对比硫酸、三氟乙酸和强酸型阳离子交换树脂催化水解阿卡波糖的效果,证实强酸型阳离子交换树脂效果最好,并且在催化水解的同时,产物Valienamine生成后即被吸附在树脂上,糖类副产物水洗即可除去;在实验选择的树脂中,以Amberlyst A-15催化活性最强,阿卡波糖水解率可达95.6%,国产001×7树脂水解率虽稍有逊色,但洗脱容易;选择9种大孔吸附树脂分别对Valienamine进行吸附和解析纯化试验,其中H1020型号树脂效果最好,80%甲醇解析效果最好;采用活性炭纯化Valienamine,用量为25mg/g阿卡波穰时,纯化效果最好,本实验条件下得到的Valienamine纯度为98.26%,得率为74.3%.     

Symmetry energy from neutron-rich fragments in heavy-ion collisions, and its dependence on incident energy, and impact parameters

The yields of fragments produced in the 60Ni+ 12C reactions at 80 A and 140 A MeV, and with maximum impact parameters of 1.5, 2 and 7.3 fm at 80 A MeV are calculated by the statistical abrasion-ablation model. The yields of fragments are analyzed by the isobaric yield ratio (IYR) method to extract the coefficient of symmetry energy to temperature (asym/T ). The incident energy is found to influence asym/T very little. It’s found that asym/T of fragments with the same neutron-excess I = N-Z increases when A increases, while asym/T of isobars decreases when A increases. The asym/T of prefragments is rather smaller than that of the final fragments, and the asym/T of fragments in small impact parameters is smaller than that of the larger impact parameters, which both indicate that asym/T decreases when the temperature increases. The choice of the reference IYRs is found to have influence on the extracted a sym /T of fragments, especially on the results of the more neutron-rich fragments. The surface-symmetry energy coefficient (bs/T ) and the volume-symmetry energy coefficient (bv/T) are also extracted, and the bs/bv is found to coincide with the theoretical results.