Construction of Larger Area Density-Uniform Plasma with Collisional Inductively Coupled Plasma Cells

The plasma density and electron temperature of a multi-source plasma system composed of several collisional inductively coupled plasma （ICP） cells were measured by a doubleprobe. The discharges of the ICP cells were shown to be independent of each other. Furthermore, the total plasma density at simultaneous multi-cell discharge was observed to be approximately equal to the summation of the plasma density when the cells discharge separately. Based on the linear summation phenomenon, it was shown that a larger area plasma with a uniform density and temperature profile could be constructed with multi-collisional ICP cells.     

Plasma Approach for Generating Ultra-Intense Single Attosecond Pulse

In our previous work,a plasma approach for single attosecond pulse (AP) generation was proposed.A few-cycle relativistic circularly polarized laser pulse will induce a single drastic oscillation of plasma boundary,from which high-order harmonics and furthermore an ultra-intense single AP can be generated naturally after it is reflected.Analytical model and simulations both demonstrate that the process is mostly efficient as the pulse duration is close to the plasma responding time.The effects of plasma density ramp are analyzed here,suggesting that the proposal is still quite efficient with appropriate density gradient in the ramp.At last,a combined approach is employed to obtain single AP with 30 fs incident laser.The relatively large-duration pulse is firstly shortened by a density dropping thin foil,and then reflected from an overdense plasma target.One-dimensional simulation shows that a 600 as single light pulse is generated with peak intensity of 3×1020W/cm2.     

SiO_2膜的孔径调节及疏水改性

以正硅酸乙酯为前驱体,添加聚丙烯酸[1](PAA)来增大SiO_2膜的孔径,并用聚合物溶液沉淀相转化法[2-3]对其进行疏水改性。通过热重分析(TG-DTG)、红外光谱(IR)、X射线衍射(XRD)、原子力显微镜(AFM)、比表面积(BET)以及接触角测量等对试样的热稳定性、化学组成、物相组成、比表面积及孔径分布、表面形貌和疏水性能等进行分析。结果表明,当PAA加入量为10%(体积分数,下同),800℃烧成后膜孔径可达53.73 nm。随PAA加入量增多,SiO_2膜孔径增大,但当加入量达到15%,800℃下焙烧时,膜表面开始出现裂纹;疏水改性后SiO_2膜的接触角的可增大至113°,但改性后的SiO_2膜孔洞明显较小,原因是涂覆于膜面的二甲基二乙氧化硅(DDS)堵塞了孔洞。可以得出在PAA加入量为10%~15%之间,600℃焙烧时,SiO_2膜可获得良好的疏水性。     

Radio Frequency Underwater Discharge Operation and Its Application to Congo Red Degradation

Radio frequency(RF) underwater discharge operation was performed for different liquid conductivities driven by different frequencies ranging from 13.56 MHz to 60 MHz,and its application to organic degradation was investigated.The RF underwater discharge was observed to be generated within the bubble at electrode surface formed by RF and plasma heating.It was shown that the sizes of the bubbles and plasmas increased as the driving frequency and the input power went up.The breakdown voltage decreased rapidly with the increase of the water conductivity and driving frequency.Comparative experiments of the UV-VIS absorbance spectra of Congo Red solution before and after discharge suggested effective degradation of the organic dye due to the active species generated during the discharge,such as.OH,.O,.H,etc.revealed by optical emission spectroscopy.The results show that higher exciting frequency and lower conductivity of the solution are more effective for organic degradation.With the combination of Fourier Transform Infrared Spectroscopy(FT-IR) and Liquid Chromatography-Mass Spectrometry(LC-MS) data,one possible degradation process was proposed and the main conceivable components and structures of the products were also presented.     

基于激光引导的静电激波产生单能重离子束

惯性约束聚变的快点火方案、癌症治疗等这些重要的应用均需要单能的离子柬.近来通过激光与等离子体相互作用加速产生高能离子已经成为一个研究热点,因其造价和占用空间都远小于传统加速器.同前已经提出了很多种加速机制,其中靶后鞘层加速较为成熟,实验上已经利用强度为3×1020 w·cm-2的激光产生出最高能量为58 MeV的质子束,也有利用微结构靶产生能散度约为20%的质子束.本文研究的足另一种重要的加速机制,激波加速.     

激光与薄膜靶相互作用产生准单周期相对论脉冲与高能质子束

目前等离子体镜及其他技术的发展使得强激光的对比度得到极大提高,纳米尺度薄膜靶的制作也得以实现,这为研究强激光与薄膜靶相互作用提供了条件。相对论激光与     

钨酸铋基光催化材料的研究进展

钨酸铋(Bi_2WO_6)是一类具有非金属含氧酸盐结构的新型光催化剂材料,其具备高稳定性、纳米结构、高催化性能等优点,但Bi_2WO_6的带隙相对较大(2.7e V),只能吸收450nm以下的光。通过对Bi_2WO_6的复合改性可以将其光吸收范围扩大,减少空穴电子对的复合,从而改善材料的光催化活性。首先介绍Bi_2WO_6的晶体结构和电子结构;其次对近几年Bi_2WO_6基光催化材料的合成方法、形貌特征光催化活性等方面的研究现状进行全面的综述分析;最后对Bi_2WO_6基光催化材料的发展趋势进行了展望。