首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13篇
  完全免费   10篇
  物理学   23篇
  2017年   2篇
  2015年   1篇
  2013年   2篇
  2012年   6篇
  2011年   1篇
  2009年   2篇
  2008年   2篇
  2007年   1篇
  2006年   3篇
  2005年   1篇
  2004年   1篇
  1988年   1篇
排序方式: 共有23条查询结果,搜索用时 93 毫秒
1.
激光触发多级多通道开关触发延迟及其抖动特性   总被引:11,自引:10,他引:1       下载免费PDF全文
 研究了激光触发多级多通道开关的触发延迟时间及其抖动与激光脉冲能量等实验参量的依赖关系,建立了零维数值模拟模型对实验现象进行了理论解释。实验结果表明:触发延迟时间及其抖动随激光脉冲能量、工作电压、气压上升呈下降趋势;随SF6-N2混合气中SF6体积百分含量上升呈上升趋势。欠压比大于等于90%时200kV原理型激光触发多级多通道开关触发延迟时间抖动小于1ns。  相似文献
2.
分光光度法快速测定海虾中呋喃唑酮残留量   总被引:3,自引:0,他引:3  
建立了快速检测水产品中呋喃唑酮残留量方法.采用分光光度法,以校准曲线法、标准加入法检测海虾、养殖虾中呋喃唑酮残留量.结果表明,本方法线性范围为0.25-20.0μg/mL,r=0.9988,检出限为2.5μg/kg,相对标准偏差<4.3%,回收率为97%-102%.方法准确、灵敏、简便,适合实验室快速检验.  相似文献
3.
为监测冬小麦冠层含水量,根据TM5的波段响应函数,将不同灌溉条件下地面实测的冬小麦冠层窄波段光谱数据转化为TM5的宽波段反射率,计算了水分指数(NDWI和WI);同时,利用地面实测数据计算了冠层含水量(FMC和EWTc),并对水分指数和冠层含水量进行回归分析。结果表明,TM5的b7比b5波段在反演冬小麦冠层水分含量方面优势明显,NDWI比WI更具优势;利用最小二乘法建立了NDWI(b4,b7)与冬小麦冠层含水量的最佳拟合方程,反演FMC和EWTc的复相关系数分别为0.576 9和0.695 6;在此基础上,对河北保定部分地区的冬小麦冠层水分含量进行了空间填图,结果显示,研究区内冬小麦冠层水分含量具有西高东低的趋势,冬小麦生长旺盛的孕穗期冠层含水量比乳熟期高。  相似文献
4.
The special flower-like and sheet-like ZnO structures were successfully synthesized by hydrothermal method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The photocatalytic activity of different morphologies of ZnO structures was evaluated by degradating of methyl orange (MO). The photocatalytic degradation process was monitored in terms of decolorization and total organic carbon (TOC) removals. The results indicated that the flower-like ZnO structures were consisted of numerous flower-like aggregates with the size of 2 μm. The sheet-like ZnO nanostructures were obtained by increasing the reaction time. They exhibited higher photodegradation efficiencies under UV light irradiation than flower-like ZnO structures due to the blue shift of the band gap. The photodegradation could be described as the pseudo-first-order kinetics with apparent rate constants ranging from 1.17 × 10−2 to 3.42 × 10−2 min−1, which were based on the morphology of the structures. The photodegradation was faster than the mineralization, indicating that the accumulation of by-products were resistant to photocatalytic degradation.  相似文献
5.
视频化测量在应力断料工艺研究中的应用   总被引:1,自引:1,他引:0  
介绍了一种基于视频检测技术和计算机图像处理技术的视频测量方法。可以对应力断料全过程进行监测,并能准确地测出相关的工艺参数。与传统检测方法相比,具有方法简单、准确、易实施、结果直观可信的特点。实践证明,视频检测方法是应力断料研究的有效的检测手段。  相似文献
6.
We report a study on the fabrication and characterization of ultraviolet photodetectors based on ZnO:Al films. Using sol-gel technique, highly c-axis oriented ZnO films with 5 mol% Al doping were deposited on Si(1 1 1) substrates. The photoconductive UV detectors based on ZnO:Al thin films, having a metal-semiconductor-metal (MSM) structure with interdigital (IDT) configuration, were fabricated by using Au as a contact metal. The characteristics of dark and photocurrent of the UV detector and the UV photoresponse of the detector were investigated. The linear current-voltage (I-V) characteristics under both forward and reverse bias exhibit ohmic metal-semiconductor contacts. Under illumination using monochromatic light with a wavelength of 350 nm, photo-generated current was measured at 58.05 μA at a bias of 6 V. The detector exhibits an evident wide-range spectral responsivity and shows a trend similar to that in transmittance and photoluminescence spectrum.  相似文献
7.
In this paper a projectile ions recoil ions coincidence technique is employed to investigate the target ionization and projectile charge state changing processes in the collision of 0.22-6.35 MeV Cq^+ (q = 1 - 4) ions with argon atoms. The partial cross section ratios of the double, triple, quadruplicate ionization to the single ionization (or the single capture) of argon associated with single electron loss (or single electron capture) by the projectile are measured and compared with the previous experimental results. In the present experiment, it is observed that the ratios of ionization cross sections R associated with single loss and single capture depend strongly on the projectile charge state and vary significantly with different reaction channels as impact energy increases. In addition, this paper gets empirical scaling laws for the ionization cross section ratios R corresponding to the projectile single loss and finds that the ratios of the double ionization to the single ionization associated with single electron capture remain constant in the present energy range.  相似文献
8.
经X射线光电子能谱(XPS)分析,在空气等离子体和氩等离子体作用下,(PET)表面上结合了不同的氮化合物。特别是在氩等离子体作用5min以后,N15出现双峰,表明PET表面上结合了氮的氧化官能团。通过低能氮离子和氩离子轰击PET表面的实验,证明这种N15双峰结构不是低能离子单独作用引起的。  相似文献
9.
 在“闪光-Ⅱ”装置上进行了1 MV同轴型水介质多针自击穿开关实验研究。开关击穿电压1~1.5 MV,开关总电流200~550 kA,电脉冲的脉宽约150 ns,上升前沿约60 ns。每个开关间隙的放电电流和输入输出电压分别用Rogowski线圈和CuSO4水电阻分压器测试。介绍了分压器的设计和标定,分析了产生误差的原因。针对类似测试,提出几点完善措施:测试电流线圈要密封隔水;水电阻分压器的第1级分压的分压比不能过大;调节CuSO4溶液的浓度,使水电阻的阻值满足频率响应的要求;注意分压器的放置方式;分压器和电流线圈的输出电压设计要适中。  相似文献
10.
An investigation of room-temperature Raman scattering is carried out on ferromagnetic semiconductor GaMnN films grown by metalorganic chemical vapour deposition with different Mn content values. New bands around 300 and 669 cm-1, that are not observed in undoped GaN, are found. They are assigned to disorder-activated mode and local vibration mode (LVM), respectively. After annealing, the intensity ratio between the LVM and E2(high) mode, i.e., ILVM=IE2(high), increases. The LO phonon-plasmon coupled (LOPC) mode is found in GaMnN, and the frequency of the LOPC mode of GaMnN shifting toward higher side is observed with the increase in the Mn doping in GaN. The ferromagnetic character and the carrier density of our GaMnN sample are discussed.  相似文献
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号