989 resultados para Niebuhr, Carsten, 1733-1815.


Relevância:

10.00% 10.00%

Publicador:

Resumo:

本发明涉及一种自由活动实验动物运动,行为和电生理指标监测分析系统,由运动轨迹识别软件(5),PC机LPT端口(4),图象采集卡(2),摄像机(1),连接在PC机LPT端口上的行为刺激装置(3)组成。该装置利用计算机和现代电子技术时实跟踪监实验动物在迷宫中的运动轨迹,并根据运动轨迹控制连接在计算机上的相关仪器给以动物相应的实验刺激,同时记录下运动轨迹并配合相关设备纪录电生理数据,达到记录行为和电生理数据同步并使实验自动化。本装置在实验任务中具有很高的灵活性,通过设置软件和调整连接在端口上不同的控制装置,可自动完成许多不同的实验任务,满足不同的数据分析需要。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this article, we detail the methodology developed to construct arbitrarily high order schemes - linear and WENO - on 3D mixed-element unstructured meshes made up of general convex polyhedral elements. The approach is tailored specifically for the solution of scalar level set equations for application to incompressible two-phase flow problems. The construction of WENO schemes on 3D unstructured meshes is notoriously difficult, as it involves a much higher level of complexity than 2D approaches. This due to the multiplicity of geometrical considerations introduced by the extra dimension, especially on mixed-element meshes. Therefore, we have specifically developed a number of algorithms to handle mixed-element meshes composed of convex polyhedra with convex polygonal faces. The contribution of this work concerns several areas of interest: the formulation of an improved methodology in 3D, the minimisation of computational runtime in the implementation through the maximum use of pre-processing operations, the generation of novel methods to handle complex 3D mixed-element meshes and finally the application of the method to the transport of a scalar level set. © 2012 Global-Science Press.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

报道中国产的淡水红藻一个新记录属——巴尔比亚藻属(BalbianiaSirodot)。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We show that the meta-converse bound derived by Polyanskiy et al. provides the exact error probability for a fixed joint source-channel code and an appropriate choice of the bound parameters. While the expression is not computable in general, it identifies the weaknesses of known converse bounds to the minimum achievable error probability. © 2013 IEEE.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The electronic structure and electron g factors of HgTe quantum dots are investigated, in the framework of the eight-band effective-mass approximation. It is found that the electron states of quantum spheres have aspheric properties due to the interaction between the conduction band and valence band. The highest hole states are S (l = 0) states, when the radius is smaller than 9.4 nm. the same as the lowest electron states. Thus strong luminescence from H-Te quantum dots with radius smaller than 9.4 nm has been observed (Rogach et al 2001 Phys. Statits Solidi b 224 153). The bandgap of H-Te quantum spheres is calculated and compared with earlier experimental results (Harrison et al 2000 Pure Appl. Chem. 72 295). Due to the quantum confinement effect, the bandgap of the small HgTe quantum spheres is positive. The electron g factors of HgTe quantum spheres decrease with increasing radius and are nearly 2 when the radius is very small. The electron g factors of HgTe quantum ellipsoids are also investigated. We found that as some of the three dimensions increase, the electron g factors decrease. The more the dimensions increase, the more the g factors decrease. The dimensions perpendicular to the direction of the magnetic field affect the g factors more than the other dimension.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Good quality hydrogenated protocrystalline silicon films were successfully prepared by radio frequency plasma enhanced chemical vapor deposition (PECVD) with various hydrogen dilution ratios (R = ([H-2]/[SiH4]) from 10 to 100). The photosensitivity of the films is up to 10(6) under the light intensity of 50mW.cm(-2). The microstructure of the films was studied by micro-region Raman scattering spectra at room temperature. The deconvolution of the Raman spectra by Gaussion functions shows that the films deposited under low hydrogen dilution ratios (R < 33) exhibit typical amorphous properties, while the films deposited under high hydrogen dilution ratios (R > 50) possess a diphasic structure, with increasing crystalline volume fraction with R. The size of the crystallites in the diphasic films is about 2.4 mm, which was deduced from the phonon confinement model. The intermediate range order of the silicon film increases with increasing hydrogen dilution ratio.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

数字作品的所有权证明允许在不泄漏任何秘密信息和防止所有者欺骗的前提下,对版权声明进行验证,提出一种基于Proactive可验证秘密共享和安全多方计算的数字作品所有权证明方案.在该方案中,可验证秘密共享,保证了所有权秘密的正确性,并防止对协议参与者的欺骗逼过Proactive安全提供自动恢复功能来保证协议生存周期内秘密的完整性和安全性.使用安全多方计算和同态承诺的零知识证明,实现了所有权验证,在不假设可信方存在的前提下,所提出方案能够在没有太多成员合谋的情况下,完成有效计算并发现不忠实成员.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

采用直接键合的方法成功实现了n-GaAs和p-GaN晶片的高质量键合.扫描电子显微镜观测结果表明,键合界面没有空洞.键合前后光致发光谱测试表明,键合工艺对材料质量影响不大.室温下界面的电流-电压特性表明,键合得到的n-GaAs/p-GaN异质结为肖特基二极管并且理想因子为1.08.n-GaAs和p-GaN材料直接键合的成功对于集成GaAs和GaN材料制备光电集成器件有重要意义.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

通过改变氢气对硅烷气体的稀释程度,并保持其他的沉积参量不变,用等离子体增强化学气相沉积(PECVD)方法成功地制备出非晶/微晶相变过渡区域的硅薄膜样品。测量了样品的室温光电导和暗电导,样品的光电性能优越,在50 mW·cm~(-2)的白光照射下,光电导和暗电导的比值达到10~6。在室温下用微区喇曼谱研究了薄膜的微结构特性,用高斯函数对喇曼谱进行了拟合分析。结果表明,在我们的样品制备条件下,当H_2和SiH_4的流量比R较小时,样品表现出典型的非晶硅薄膜 的结构特性;随流量比R的增大,薄膜表现出两相结构,其中的微晶成分随氢稀释比的增大逐渐增多;用量子尺寸效应估算了两个高氢稀释样品(R > 50)中微晶粒子的平均尺寸大小为2.4 nm左右;样品的中程有序度随氢稀释程度的增加而增大。