南京开设信息高速公路“中转站”

CHINA ONLINE系统8大“信息中转站”之一的南京节点已正式开通.这意味着包括南京、上海、杭州、南昌等8城市可通过此节点,向全国以至全球信息高速公路上的用户尽快实现     

SIMULATION OF THE SEISMIC TECTONIC STRESS FIELD IN NORTH CHINA

The paper reviews several methods of simulation used in this country to recover currenttectonic stress field related to earthquake occurrence in North China. The aim is to evaluatethe degree of seismic risk around Beijing area. The methods used are computational ormathematical simulation by the finite element method and experimental or physical simulationby the photoelastic method and the grid method. The results obtained by these methods arebriefly described. Most simulations indicate that Beijing is not a region of seismic risk.     

砷化镓气相掺硫外延和亚微米薄层的制备

本文介绍了Ga-AsCl_3-H_2体系,研究了气相外延时硫的掺杂行为,讨论了硫的掺杂机理和生长了亚微米薄层。制得的亚微米外延层的质量表明,表面形貌良好,缺陷少,重复性好。典型的电学性质为:当厚度≤0.4μm和浓度为1—2×10~(17)/cm~3时,击穿电压V_B=7—10V。在单层和多层外延结构中,界面浓度基本是突变的,过渡区约0.1μm。这些外延片已用于制备变容管和远红外探测器等。     

氦-氖激光治疗带状疱疹

带状疱疹为病毒感染所致的皮肤病.在红斑性皮损基础上发生群集成簇的小疱疹,常沿一条或多条节后神经分布伴有剧烈疼痛,常引起患者极大痛苦.我们应用激光治疗了153例带状疱疹,大多数病例经过3～4次治疗即可痊愈,疗效显著,方法简便.     

一种基于BP神经网络和呈色原理的扫描仪色彩管理新模型

在计算机技术和多媒体技术中,扫描仪是图象信息输入的主要输入设备之一,其色彩管理模型是图像在随后复制和传输过程中保持色彩一致性的关键.本文在分析扫描物呈色原理的基础上,提出了一种基于BP神经网络的扫描仪色彩管理模型.首先,该模型对扫描数据进行归一化的预处理,以满足BP网络对数据取值范围的要求;其次,该模型以彩色梯尺区色块代表整个色空间,以减少模型的运算量;再次,模型采用运动量动态调整模型步长,以加快BP网络收敛速度.最后,实验结果表明本文模型提高了色彩转换精度,能够满足扫描仪色彩管理的工程应用需求.     

First-Principles Study of Structural and Electronic Properties of Layered B2CN Crystals

Based on the hexagonal BN structure, six possible layered B~ CN structures are constructed. Their total energies, lattice constants as well as electronic properties are calculated using the ab initio pseudopotential density functional method within the local density approximation. The calculated results show that the B2 CN-V configuration with AA stacking sequence is the most stable among the six B2CN layered structures. The characteristics of electronic structures indicate that the B2 CN-V shows metallicity, which mainly comes from -B1-C-B1-C- chains.     

Bounce-Averaged Acceleration of Energetic Electrons by Whistler Mode Chorus in the Magnetosphere

We construct the bounce-averaged diffusion coefficients and study the bounce-averaged acceleration for energetic electrons in gyroresonance with whistler mode chorus. Numerical calculations have been performed for a band of chorus frequency distributed over a standard Gaussian spectrum specifically in the region near L = 4.5, where peaks of the electron phase space density occur. It is found that whistler mode chorus can efficiently accelerate electrons and can increase the phase space density at energies of about 1 MeV by more than one order of magnitude about one day, in agreement with the satellite observations during the recovery phase of magnetic storms.     

荧光光源光学效率的测量

引言本文论述的技术适用于测量荧光光源的光效。当在空气中对无罩灯做光学测量时,为使其保持在相同的最小灯壁温度(MLWT)下,在灯上连接了珀尔帖装置。用三种不同的灯镇流系统(40WF40T-12型灯,34WF40T-12型灯和32WF40T-8型灯)测量了光源的装置效率和光效率。因为实验室中没有角-光度计以直接测定装置的流明输出,所以采用测量该装置照度的方法来估计总亮度。相当的测量可以比较每一光源与不同灯镇流组合的效率,并证实了在实验室测量中使用珀尔帖装置这一技术的可行性。基本概况装置效率是用于为光源定性的一种参数。这个参量不仅取决于几何结构设计和材料特性,而且取决于测量中使用何种灯镇流系统。以往由于只有一种通用的灯镇流系绒(CBM镇流器和40WF401-12型灯),所     

ZnO基质荧光粉的新合成方法及其发光特性

对信息显示不断增长的需求在于对显示器件使用的荧光粉有着不同的,有时甚至是严格的技术要求。尤其是,几乎没有适用于低压下,如在等离子体 CRT 器件中工作的商品化荧光粉。具有高传导性、又可在低压下工作的几种荧光粉之一是 ZnO:Zn。纵观商品化的荧光粉以及具有本征发光特性的荧光粉颗粒形态的相关性,促使作者研究了