同步辐射圆二色谱研究氧化石墨烯与腐殖酸的相互作用

应用同步辐射真空紫外圆二色光谱、紫外-可见及红外光谱等技术研究了氧化石墨烯(Graphene Oxide,GO)与腐殖酸(Humic Acid,HA)在水溶液中的相互作用,探讨了不同配比、溶液p H及不同温度条件下GO与HA之间的相互作用对GO在水溶液中形态的影响。研究表明,一定条件下GO在水溶液中显示出圆二色性,其强弱与GO在水溶液中的形态结构有关。HA可通过极性相互作用和π-π相互作用吸附在GO表面,形成GO-HA复合物,改变体系的圆二色性,这种影响与二者的质量比、水环境p H和温度相关。GO-HA与GO相比,厚度增加,分散性提高,圆二色信号降低;GO-HA体系p H值升高和温度降低,有利于GO-HA折叠构象的形成,使得体系的圆二色信号升高。     

二氟沙星光敏损伤溶菌酶的十二烷基磺酸钠-聚丙烯酰胺凝胶电泳研究

本文采用稳态光照的方法研究了二氟沙星药物对溶菌酶生物大分子的光敏损伤.研究发现,在315～375 nm波长的光照射下,二氟沙星药物能够光敏损伤溶菌酶类大分子物质.通过十二烷基磺酸钠-聚丙烯酰胺凝胶电泳分析光照产物发现,生物大分子的光敏损伤途径和损伤产物与二氟沙星药物的浓度、光照时间、光照气氛等条件密切相关.其他条件相同...     

同步辐射圆二色谱法研究Fe3O4纳米颗粒对细胞色素C结构的影响

四氧化三铁纳米颗粒(Fe3O4-NPs)在生物医学领域有着广泛的应用。通过同步辐射真空紫外圆二色谱(SRCD)和紫外可见(UV-Vis)吸收谱技术研究了Fe3O4纳米颗粒的粒径(10 nm和40 nm)对细胞色素C(Cyt c)结构的影响。结果表明,随着Fe3O4-NPs颗粒物浓度的增大,Cyt c在408 nm处的吸光度值逐渐下降。SRCD结果显示Cyt c与Fe3O4-NPs作用后,蛋白的α螺旋含量减少,β折叠含量增加;Fe3O4-NPs与Cyt C的作用强度具有尺寸依赖性,小尺寸的Fe3O4-NPs作用更为明显。     

一氧化氮合成酶对AQ4N放射增敏作用的影响研究

评价1，4-二-[[2-（二甲氨基-N-氧化物）乙醇]氨基]5，8-双羟基氧化蒽-9，10-二酮（（1，4-bis{[2-（dimethylamino-N-oxide）ethyl]amino}-5，8-dihydroxyanthracene-9，10dione），AQ4N）辐射增敏效果和乏氧选择性，分析一氧化氮合成酶（Inducible nitlogen monoxide synthase，iNOS）对AQ4N代谢活化的影响和作用特点。结果显示AQ4N是一种低毒性的化合物，仅在乏氧条件显示较弱的细胞毒性，可以引起肿瘤细胞凋亡。AQ4N对肿瘤细胞尤其是乏氧肿瘤细胞具有良好的辐射增敏作用。同亲本细胞相比，iNOS基因转染的细胞克隆，仅在乏氧条件下显示出对AQ4N化学敏感性的增强和细胞的G2／M期阻滞。提示iNOS仅在乏氧条件下参与AO4N的代谢活化过程。     

Studies of the interaction of slow very highly charged ions with solid surfaces using the LLNL EBIT facility

A summary of the present status of the LLNL EBIT based research program on highly charged ion-solid surface interaction is presented. New results for coincidence measurements of K−K^β X-ray emission for Fe²⁶⁺ incident on Al, using two Ge detectors are presented. It is shown that excellent resolution of the satellite and hypersatellite lines are achieved, in excess of what is possible with single Ge detector measurements. Recent results from ongoing investigations on electron emission, sputtered ion and energy loss phenomena are presented. Results from charge-state analysis of grazing incidence specular scattering of highly charged ions off atomically flat surfaces of gold, carbon and mica indicate that the incident ion essentially reaches ground state of its electronic distribution within the ion-surface interaction time of 100 fs. Atomic force microscopy is used to investigate the formation of a new type of ion induced surface defect, peculiar to highly charged ion-surface interactions. A linear correlation, between the defect volume and the incident ion charge, supports a mechanism of defect formation due to potential energy induced electron emission and subsequent collective displacement due to local charge imbalance.     

喹啉及其衍生物的脉冲辐解和激光光解研究

Quinoline and some of its derivatives were reported to be carcinogenic, toxic and mutagenic. The widespread use of quinoline and its derivatives entails that these compounds are distributed in the environment, polluting soil and water together with many other environmental chemicals.     

Study of the interaction of resonance neutrons with nuclei on the linear accelerator in saclay

Conclusions We expect that when the third section of the accelerator is set up, increasing the energy of the electrons to 45 MeV, and experiments with more intense neutron beams begin, a great deal of data will be obtained on the relation between the statistical properties of resonances for medium nuclei situated in the range 5 to 100 keV and the spin. In this region, where a resolution of 0.1 nsec/m can be attained, the system used in Saclay may successfully compete with the Van der Graaf accelerator. On the other hand, the intensive development of studies on the partial radiative widths at higher intensity or resolution should lead to the improvement of existing results.(Center for Nuclear Studies, Department of Low-Energy Nuclear Physics, Saclay, France) Translated from Atomnaya Énergiya, Vol. 19, No. 1, pp. 8–14, July, 1965Translation from French     

Basic Studies on Two-Phase Flow with the Use of Electrical Void-Meter

Further basic knowledge has been gained on the behavior of two-phase flow through the following experiments. An electrical void-meter based on transducement of void fraction into impedance is employed to measure the void distribution along a heater in an annular channel.

Experiments have further been conducted on the “velocity slip ratio (V_g/V₁)” to correlate the void-fraction (R_g,) with the volume flow rate ratio (F_g). The resulting equation takes the form R_g= 0.92-F_g and the ratio V_g/V_g= 1.08, for slug flow in a vertical pipe.

Statistical methods have been applied in analyzing the two-phase flow. It is shown that the speed of voids in a two-phase flow can be determined with a cross-correlation function calculated from two time series of void-fraction fluctuation measured at two points along the channel.     

Study on the interaction mechanism of double-blade corona discharge with a large discharge gap

Multi-source corona discharge is a commonly used method to generate more charged particles,but the interaction mechanism between multiple discharge sources, which largely determines the overall discharge effect, has still not been studied much. In this work, a large-space hybrid model based on a hydrodynamic model and ion-transport model is adopted to study the interaction mechanism between discharge sources. Specifically, the effects of the number of electrodes,voltage level, and electrode spac...