首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 671 毫秒
1.
移动通信网HSS具备2/3G、EPC及IMS三融合网络功能,但系统本身缺乏基于用户业务特征的数据导出功能。本文结合业务数据特征,充分发挥系统潜能,通过在设备上部署DTL用户导出功能,实现了HSS用户数据的精准导出和灵活管理,保障了设备侧与BOSS业务签约的一致性,提升了用户感知。  相似文献   

2.
在智能卡进行多行业应用时,存在跨行业数据访问、数据泄露以及破坏等安全问题.针对此类问题,结合当前智能卡安全机制和跨行业多应用的文件系统特征,提出了对多应用智能卡数据完整性校验的一种方法.该方法构建了一个文件加密与访问控制模型,其主要功能包括保障各行业应用系统的独立性,实现数据的访问控制和密钥的安全存储等.最后分析并验证了该安全模型的可行性与安全性.该方案在陕西省社会公共服务卡验证平台上得到了验证,提高了卡内数据信息的安全级别.  相似文献   

3.
为了满足我校电气工程及其自动化专业本科教育培养适应电力电子行业需求人才,结合目前功率半导体器件和电力电子技术发展趋势,建设紧扣第三代半导体器件的《宽禁带电力电子器件的原理与应用》课程。教学内容有机分为三大模块和七个学习阶段,逐步推进。在教学过程中,引入“教师引导、自主学习、问题导向、扩展视野”的教学理念,将启发式、讨论式、任务驱动式等多种教学方法互相配合使用,充分激发学生的学习兴趣,加深对器件知识的理解,强化器件测试和应用能力,着力培养学生分析问题和解决问题的能力。  相似文献   

4.
生长速率较快及由于非均匀晶场可能限制谱线的增宽,导致美国贝耳实验室的小布兰德(C. D. Brandle, Jr.)和范德利登(C. Y. Vanderleeden)研究Gd3Sc2Al3O12(GADSCAG),把它作为一种可能代替YAG的掺钕基质材料。在同一钨灯泵浦的腔内对几根Nd:GADSCAG棒和一根Nd:YAG控制棒作了试验,发现Nd:GADSCAG棒的光损耗比Nd:YAG棒的高0.5~1.0%。至少其部分原因是由于原材料中存在百分之五的杂质铁。在把泵浦功率转换为激光输出功率方面,GADSCAG棒的效率相当于YAG棒的80%。由于GADSCAG棒的生长速率比YAG棒的快三倍,从经济观点来看,这种材料对于某些应用是有吸引力的。  相似文献   

5.
6.
采用单辊快淬法制备了Fe81Zr7Nb2B10和Fe78Co2.5Zr7Nb2B10Cu0.5非晶合金,在不同温度下对两种合金进行了热处理。利用差热分析仪(DTA)、X射线衍射仪(XRD)和振动样品磁强计(VSM)等仪器对两种合金的热性能、微观结构和磁性能进行了测试分析。结果表明在Fe78Co2.5Zr7Nb2B10Cu0.5合金的晶化过程中存在预结晶效应,而在Fe81Zr7Nb2B10合金的晶化过程中没有。Fe81Zr7Nb2B10和Fe78Co2.5Zr7Nb2B10Cu0.5合金经803 K退火后,分别有α-Fe和α-Fe(Co)相从非晶基体中析出。随退火温度的升高,两种合金的比饱和磁化强度(Ms)变化趋势相似,但矫顽力(Hc)变化趋势明显不同。  相似文献   

7.
苏修结晶学研究所的科学工作者以1.5千瓦的泵浦功率在Y3Al5O12/Nd3+晶体中获得了脉冲激光作用。釆用的晶体中的一些由助熔盐法生长,而另一些则由熔融法生长。高能态(4F3/2)的寿命(在室温和室温以下) 从0.2变化到0.18微秒。  相似文献   

8.
采用第一性原理计算,研究了有机金属卤化物钙钛矿CH3NH3PbI3和CH3NH3MnI3的电子结构、磁性和光吸收。CH3NH3PbI3和CH3NH3MnI3都是具有直接带隙半导体,CH3NH3MnI3磁基态为G型反铁磁序(G-AFM)。CH3NH3MnI3在G-AFM状态下的带隙值为1.668 eV;当系统处于FM态时,多数自旋通道的带隙为0.696 eV,少数自旋通道的带隙为2.148 eV。结果表明,具有FM态的CH3NH3MnI3的光激发电子将迅速熔化局域磁序。最后计算了CH3NH3PbI3和CH3NH3MnI3的光学特性,结果表明具有铁磁态的CH3NH3MnI3(FM)表现出较强的红外光吸收。  相似文献   

9.
到目前为止,在260种激光基质晶体中[1],压电晶体仅有4种。之所以如此少的原因是存在着一系列的基本困难,其中,主要是熔炼炉的结构和激活问题,特别是三价稀土族离子(TR3+)的激活问题。尽管如此,激光压电晶体仍然在解决固体物理、量子电子学和声学中一系列很有价值的问题方面引起人们极大的兴趣。  相似文献   

10.
采用传统的熔淬技术制得了低熔Al2O3-ZnO-Bi2O3-B2O3玻璃,研究了玻璃结构、玻璃特征温度、线膨胀系数(αl)以及密度随Bi2O3含量的变化关系。结果表明:随着Bi2O3含量的增加,玻璃网络中[BO4]取代了部分[BO3],玻璃网络中出现Bi—O结构,玻璃中非桥氧的数量也逐渐增多;软化温度(ts)、玻璃化温度(tg)都是先上升后下降,而线膨胀系数先减小后逐渐增大,玻璃密度先是线性增加,然后增加趋势变大。  相似文献   

11.
In0.52Al0.48As/In0.53Ga0.47As/In0.52Al0.48As n-p-n abrupt double-heterojunction bipolar transistors grown by molecular beam epitaxy (MBE) have been realized for the first time. DC current gains in excess of 300 have been measured on devices operated in the emitter-up configuration. DC current gains around 50 are obtained on device structures with Be+ implanted extrinsic base regions operated in the emitter-down configuration. The carrier injection and collection behavior of the abrupt InGaAs/InAlAs heterojunctions is discussed.  相似文献   

12.
Characteristics of BaZrO3 (BZO) modified Sr0.8Bi2.2Ta2O9 (SBT) thin films fabricated by sol-gel method on HfO2 coated Si substrates have been investigated in a metal-ferroelectric-insulator-semiconductor (MFIS) structure for potential use in a ferroelectric field effect transistor (FeFET) type memory. MFIS structures consisting of pure SBT and doped with 5 and 7 mol% BZO exhibited memory windows of 0.81, 0.82 and 0.95 V with gate voltage sweeps between −5 and +5 V, respectively. Leakage current density levels of 10−8 A/cm2 for BZO doped SBT gate materials were observed and attributed to the metallic Bi on the surface as well as intrinsic defects and a porous film microstructure. The higher than expected leakage current is attributed to electron trapping/de-trapping, which reduces the data retention time and memory window. Further process improvements are expected to enhance the electronic properties of doped SBT for FeFET.  相似文献   

13.
Several beat frequencies in the range below 6 GHz have been measured using a C12O216laser and a C12O218laser operating on several pairs of closely spaced lines in the 9.3-μm region.  相似文献   

14.
The wavelength, polarization, and output power of several lines of the optically pumped CW FIR12CH316OH (methanol) and12CH316OD (1-D deuterated methanol), methyl iodide, methyl bromide, and deuterated methylene chloride lasers have been determined. In addition to lines already reported in the literature, seven strong lines have been observed. Optimum performance of the laser system is achieved by means of an improved coupling of the CO2pump power into the resonator and extraction of the FIR power from the resonator. Measurements on the power absorption coefficient of water using the laser indicate thatalpha(bar{nu})rises to almost 1100 Np ċ cm-1at 170 cm-1, and then shows a gradual fall with an increase in frequency. A strong temperature dependence of the 200 cm-1peak inalpha(bar{nu})is predicted, with a decrease in the frequency of maximum power absorption coefficient with an increase in temperature. The range of measurements for acetonitrile is extended to lower frequencies so as to overlap with those determined from other millimeter wave techniques. For highly power-absorbing liquids,alpha(bar{nu})is estimated to be within ± 5 percent.  相似文献   

15.
We report the observation of lasing at 0.9137 μm and 1.3545 μm in neodymium-doped KY(WO4)2at 77 K. Transition cross sections, fluorescent line width, and branching ratios are given.  相似文献   

16.
A new Al0.25In0.75P/Al0.48In0.52 As/Ga0.35In 0.65As pseudomorphic HEMT where the InAs mole fraction of the Ga1-xInxAs channel was graded (x=0.53→0.65→0.53) is described. The modification of the quantum well channel significantly improved breakdown characteristics. In addition, use of an Al0.25In0.75P Schottky layer increased the Schottky barrier height. Devices having 0.5 μm gate-length showed gm of 520 mS/mm and Imax of 700 mA/mm. The gate-drain (BVg-d) and source-drain (BVd-s ) breakdown voltages were as high as -14 and 13 V, respectively. An fT of 70 GHz and fmax of 90 GHz were obtained  相似文献   

17.
费林  王克俊  诸旭辉 《中国激光》1985,12(9):524-527
我们研制了一台~(14)CO_2-~(12)CO_2同位素激光器,测量到激光谱线80条,其中40条是~(14)CO_200°1-(10°0,02°0)_I带的激光跃迁谱线,强线输出功率达4.0W以上;实验还观察到同位素的竞争效应,发现即使~(14)CO_2成份低于~(12)CO_2,其激光辐射仍占优势.  相似文献   

18.
A high-speed waveguide In0.53Ga0.47As-In0.52Al0.48 As separate absorption, charge, and multiplication avalanche photodiode suitable for operation at 1.55 μm has been demonstrated, a unity-gain bandwidth of 27 GHz was achieved with a gain-bandwidth product of 120 GHz  相似文献   

19.
A heterostructure metal-insulator-semiconductor field-effect transistor (MISFET) with a modulation-doped channel is proposed. In this device, a very thin undoped subchannel is located between the undoped wide-bandgap insulator and a thin heavily doped channel. In the depletion mode of operation, electron transport takes place along the heavily doped channel. When the device enters the accumulation mode of operation, electrons pile up against the heterointerface in the high-mobility undoped subchannel. This results in markedly improved transport characteristics at the onset of accumulation. The concept is demonstrated in the In0.52Al0.48As/In0.53 Ga0.47As system on InP. A 1.5-μm-gate-length MISFET shows a unity current-gain cutoff frequency of 37 GHz  相似文献   

20.
The temporal stability of trapped transport current in annular thin film Tl2Ba2CaCu2O8 (TBCCO) and YBa2Cu3O7 (YBCO) wafers has been accurately measured and has been found to be of suitable quality for the stringent requirements of nuclear magnetic resonance (NMR) magnets. No detectable decay, to the limit of the experimental apparatus (2*10-14 Ω), was detected in those wafers with transport current at or below the critical current density Jc. The critical current density, as previously determined from 12 μm meander lines, was confirmed in a wafer with a width of 1.9 cm. The profile of trapped magnetic field resulting from induced current was modeled in order to assess its effect on the uniformity of an NMR magnet  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