排序方式: 共有61条查询结果,搜索用时 750 毫秒
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圆筒状DBD放电特性模拟研究 总被引:1,自引:0,他引:1
用XOOPIC软件对同轴圆筒状反应装置DBD放电特性进行了二维模拟研究。在频率为20kHz、正弦电压幅值为5kV的大气压氩气放电中,再现了微放电通道形成和发展过程,其微放电的寿命约为4ns。获得了电子、离子、介质表面电荷密度和电场强度随空间和时间的分布,发现在高压线圈的位置附近电子、离子和介质表面电荷密度存在极值。与典型平板介质阻挡放电相比,微放电中的电子密度、场强增加2~3个数量级。 相似文献
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Detailed structural,mechanical,and electronic study of five structures for CaF2 under high pressure 下载免费PDF全文
Detailed density functional theory(DFT)calculations of the structural,mechanical,thermodynamic,and electronicproperties of crystalline CaF2 with five different structures in the pressure range of 0 GPa–150 GPa are performed byboth GGA(generalized gradient approximation)-PBE(Perdew–Burke–Ernzerhof)and LDA(local density approximation)-CAPZ(Cambridge Serial Total Energy Package).It is found that the enthalpy differences imply that the fluorite phase→PbCl2-type phase→Ni2In-type phase transition in CaF2 occurs at PGGA1=8.0 GPa,PGGA2=111.4 GPa by usingthe XC of GGA,and PLDA1=4.5 GPa,PLDA2=101.7 GPa by LDA,respectively,which is consistent with previousexperiments and theoretical conclusions.Moreover,the enthalpy differences between PbCl2-type and Ni2In-type phases inone molecular formula become very small at the pressure of about 100 GPa,indicating the possibility of coexistence of twophase at high pressures.This may be the reason why the transition pressure of the second phase transition in other reportsis so huge(68 GPa–278 GPa).The volume changed in the second phase transition are also consistent with the enthalpydifference result.Besides,the pressure dependence of mechanical and thermodynamic properties of CaF2 is studied.Itis found that the high-pressure phase of Ni2In-type structure has better stiffness in CaF2 crystal,and the hardness of thematerial has hardly changed in the second phase transition.Finally,the electronic structure of CaF2 is also analyzed withthe change of pressure.By analyzing the band gap and density of states,the large band gap indicates the CaF2 crystal isalways an insulator at 0 GPa–150 GPa. 相似文献
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采用微波消解样品-石墨炉原子吸收光谱法测定镍基高温合金中的痕量银。采用硝酸-氢氟酸-水(5+1+5)溶液对样品进行微波消解,以硝酸钯-硝酸镁的混合溶液为基体改进剂,石墨炉灰化温度为1 000℃,原子化温度为1 850℃,采用塞曼校正技术扣除背景。方法的检出限(3s/k)为2.3pg,加标回收率在98.3%~104%之间。方法应用于镍基高温合金中痕量银的测定,ICPMS的测定结果与之相吻合。 相似文献
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研究了CS2分子^1B2(^1∑u^+)预离解态线形势垒下的g振动能级光解动力学,包括预解离寿命、产物振转布居、平动-振动-转动能量分配和解离通道分支比.在实验过程中,一束可调谐激光激发超声射流冷却的CS2分子到^1B2(^1∑u^+)电子态,光解产物CS用另一束可调谐激光通过激光诱导荧光(LIF)方法检测.通过拟合光解碎片激发谱的谱峰轮廓,获得了源于不同跃迁初始态的^1B2(^1∑u^+)态g振动能级的预解离寿命.通过分析CS的LIF光谱,则获得了不同光解波长下CS碎片的v=0—8振动态布居、v=1、4—8振动态的转动布居、能量分配以及两个预解离通道CS(X^1∑^+)+S(^3PJ)和CS(X^1∑^+)+S(^1D2)的分支比.实验还考察了初始态弯曲振动量子数v2″、振动角动量量子数l对解离动力学的影响.发现v2″的影响不大,而l的影响却是明显的.较大的l(=K)对应于较短的寿命和较小的通道分支比S(^3PJ)/S(^1D2),即大的l(=K)有利于预解离的发生,同时更有利于产生S(^1D2). 相似文献
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利用紫外-可见(Uv-Vis)光谱和荧光光谱研究了超声波照射激活纳米二氧化硅(SiO2)粒子对牛血清白蛋白(BSA)分子的损伤,并考查了超声波照射时间、纳米SiO2粉末加入量、溶液酸度和超声波照射功率等因素对BSA分子损伤程度的影响.结果表明,对于体系温度为(37.0±0.2)℃和浓度为1.0×10-5mol·-1的BSA溶液,UV-Vis光谱显示,随着超声波照射时间,纳米SiO2粉末加入量,溶液pH值和照射功率的增大呈现出越来越明显的增色效应.然而,BSA溶液的荧光光谱却随着上述因素的增大呈现出越来越明显的猝灭现象.此外,还初步探讨了超声波照射激活纳米siO2粒子对BSA分子损伤的机理,认为是声致发光或高热激发使纳米siO2粒子产生·OH自由基,进而损伤溶液中的BSA分子.这一研究结果对声催化方法应用于临床治疗肿瘤以及纳米药物的开发具有一定的指导意义. 相似文献
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为验证ITO的光电性能,以不同类型ITO作为光电阳极,采用旋涂与真空蒸镀的方法制备本体异质结聚合物太阳电池ITO/PEDOT∶ PSS/P3HT∶ PCBM/Al,研究了ITO表面形貌及光场分布对太阳电池光电性能的影响.结果表明,合适的ITO厚度及表面形貌能够在有效收集空穴的同时,提高光子透过率,保证有源层对光子的吸收.合适的ITO阳极厚度及表面形貌能够有效提高聚合物太阳电池的光伏性能,使得聚合物电池的效率从0.07;提升至1.30;. 相似文献
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Fe ions of dose 8 × 1016 cm-2 are implanted into a ZnO single crystal at 180 keV. Annealing at 1073 K leads to the formation of zinc ferrite (ZnFe2O4), which is verified by synchrotron radiation X-ray diffraction (SR-XRD) and X-ray photoelectron spectroscopy (XPS). The crystallographically oriented ZnFe2O4 is formed inside the ZnO with the orientation relationship of ZnFe2O4 (111)//ZnO (0001). Superconducting quantum interference device (SQUID) measurements show that the as-implanted and post-annealing samples are both ferromagnetic at 5 K. The synthesized ZnFe2O4 is superparamagnetic, with a blocking temperature (TB = 25 K), indicated by zero field cooling and field cooling (ZFC/FC) measurements. 相似文献