Terahertz transmission properties of Cr ion implantation glass

<正>Cr ion implantations in glass with the different doses of D=1.493×10~(17) and 4.976×10~(17) ion/cm~2 are obtained by metal vapor vacuum arc(MEVVA).The effects of the different Cr ion implanted doses on terahertz(THz) transmission property are analyzed from THz time-domain spectroscopy.The results show that the more the Cr ion implanted dose in the micro-area implantation glasses,the larger the THz transmission except the larger absorption at 0.24 THz.This is an effect attributed to the coupling of plasmas on both the implantation and the implantation affected zones of the Cr ion implantation glass.     

Irreducibility, Brill-Noether loci, and Vojta's inequality

This paper deals with generalizations of Hilbert's irreducibility theorem. The classical Hilbert irreducibility theorem states that for any cover of the projective line defined over a number field , there exist infinitely many -rational points on the projective line such that the fiber of over is irreducible over . In this paper, we consider similar statements about algebraic points of higher degree on curves of any genus. We prove that Hilbert's irreducibility theorem admits a natural generalization to rational points on an elliptic curve and thus, via a theorem of Abramovich and Harris, to points of degree 3 or less on any curve. We also present examples that show that this generalization does not hold for points of degree 4 or more. These examples come from an earlier geometric construction of Debarre and Fahlaoui; some additional necessary facts about this construction can be found in the appendix provided by Debarre. We exhibit a connection between these irreducibility questions and the sharpness of Vojta's inequality for algebraic points on curves. In particular, we show that Vojta's inequality is not sharp for the algebraic points arising in our examples.

     

思科电信运营商战略--助电信运营商通过创新服务扩大收入

随着电信市场竞争的加剧以及用户对数据业务需求的不断扩大,电信运营商加快了迈向基于IP的下一代网络（IPNGN）的步伐,希望通过构建融语音、数据、视频于一体的下一代网络,快速部署创新的业务和应用,同时有效降低整体拥有成本.为此,电信运营商需要融合基础设施,在提高现有业务供应水平的同时,为未来的业务提供生命力更长久的框架,并且拥有提供增值化和个性化业务的手段,最终为用户带来全新的通信体验.     

华为GSM双密度基站规模服务全球GSM市场

GSM网络在全球仍然呈现出快速发展的势头.在中东北非地区不断涌现GSM新牌照运营商;亚太地区原有GSM网络的用户增长仍保持了较高的速度;拉美地区TDMA网络向GSM转网正方兴未艾.在中国,GSM网络每年仍新增用户4 000万以上,后续增长空间依然巨大.GSM全球用户已经接近20亿,新入网的用户ARPU值普遍较低.运营商在网络急速扩张和用户ARPU值连续下降的情况下,普遍关心能使GSM网络保持持续赢利能力的网络解决方案.     

NetStream——精细化网络流量分析之利器

一、宽带业务战国时代，宽带业务的普及速度很快,根据英国咨询公司Point Topic对全球宽带市场的调查结果,截至2005年6月底全球宽带用户已达到1.76亿,季度增长率为7.3%,同比增长率为43.1%.不断增长的用户数使得网络流量成倍增长,然而并没有使运营商的收入也成倍地增长.大量新业务如VoIP、P2P、IPTV等的涌现,对网络运营产生了深远的影响.而传统的包月式计费模式对运营商来说逐渐成为无法承受的大包袱,网络病毒攻击带来的安全性问题也使运营商如鲠在喉.。     

3G"新"彩铃引领3G新体验

3G彩铃在2G彩铃的基础上进一步演化，具备了个性化铃声和影像。用户可以自己设定动画、视频等内容。通过介绍3G彩铃的业务平台结构，描述业务平台的核心部分一业务服务器的功能。介绍了3G彩铃实现的原理基础，最后对3G彩铃业务的发展方向进行了阐述。     

On synchrotron radiation in non-uniform magnetic fields

We study the conditions in which a charged particle in an inhomogeneous magnetic field (particularly at the edges of a “long” uniform magnet or in a “short” magnet) can emit synchrotron radiation with a spectrum extending beyond the “critical frequency”. We suggest that this effect should be clearly visible (and also useful) in the case of very high energy proton storage rings.     

Étude de la dissipation d'énergie dans la fission de 234u à l'aide de la réaction 233U(d,pf)

The energy balance in the fission of ²³⁴U has been investigated on the basis of experimental results from the ²³³U(d, pf) reaction. Taking into account the neutron evaporation we have deduced the total kinetic energy and excitation energy distributions of the primary fragments as functions of the excitation energy of the fissioning nucleus. The neutron evaporation temperatures have been adjusted so as to reproduce the average value and width of the measured kinetic energy distributions for each fragmentation. Excitation energy distributions of the fragments have been deduced. The data are discussed in the framework of the liquid-drop model with shell corrections. Evidence for energy dissipation in the fission of ²³⁴U, involving drastic changes in the scission configuration, is shown for some fragmentation modes.     

Ellipticity of the Linearly Polarized He-Ne Laser Radiation Reflected by the Leaves of Plants

The phenomenon of elliptical polarization of the linearly polarized radiation reflected near the Brewster angle by the leaves of plants has been investigated. It has been shown that the appearance of ellipticity is associated with the complex structure of the cuticle.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 236–240, March–April, 2005.