丰富多彩的亚洲卫星电信市场

随着移动电视在美国的开始应用,新应用逐渐站稳了脚跟,并被美国消费者的要求所推动,而消费者的这些更丰富体验的要求在以前受到过抑制。为了在卫星电信领域更好契合这一趋势,注意亚洲发展并从其经验中总结教训这一做法是有意义的。     

Wave realisation of filters and equalisers in log-domain

Log-domain circuits offer a low-power property, whereas wave-derived circuits inherit a low-sensitivity property from the ladder prototypes and are less prone to transistor non-idealities. A novel approach to the design of wave filters in the log-domain is presented and several wave two-port topologies are investigated. Important design properties are examined. Realisations of direct filters, complex filters and group-delay equalisers in typical BJT and HBT SiGe BiCMOS technologies are assessed. The design procedures have been incorporated into XFTLTER design software.     

An analysis of the Slapper worm

We can prove that the Slapper is a variation of the Apache Scalper worm by comparing the source code. Modifications introduced in the Slapper worm improved the robustness and efficiency of its predecessor's simplistic P2P networking capabilities. Slapper's author also removed certain features from the original-either because they were redundant or to reduce the perception that it was a tool developed to cause direct harm to networks. Among the features the author removed from the Slapper were capabilities to update itself from a remotely specified Web server (perhaps to prevent someone else from replacing this version with a new one), to attack and infect a host specified with a controlling program, and to send spans. Interestingly, the ability to execute distributed denial-of-service attacks on a controlling user's behalf was kept intact. Slapper's author attempted to make communications with a remote controlling program as stealthy and untraceable as possible by removing several commands to query status and obtain feedback from Slapper nodes.     

Electrooptics of nematic-cholesteric droplets in constant electric field

Electrooptics and dynamics of twisted nematic-cholesteric liquid crystal (LC) droplets occurring in an isotropic environment in a dc electric field have been studied. The twist of the LC director field significantly influences the character of rotation of the cholesteric droplets. The most probable mechanism accounting for the rotation of cholesteric droplets is related to the Carr-Helfrich electrohydrodynamic instability.     

Microhardness of silicon layers grown by liquid phase epitaxy

The microhardness of silicon epilayers grown from Sn fluxes is found to be lower than that of the silicon substrates and to significantly depend on the crystallographic orientation of the substrates. The microhardness values follow a Gaussian distribution in all of the epilayers. Unintentional impurities are shown to have a significant effect on the microhardness of the epilayers. The addition of ytterbium to the high-temperature solution reduces the microhardness of the epilayers.     

Direct transformation of nonlinear systems into state affine MISO form for observer design

This paper gives necessary and sufficient conditions to solve in a constructive way the transformation of a general multiple-input-single-output nonlinear system into a state affine system. This result is direct i.e., without solving the state elimination problem when computing the input-output differential equation. A Kalman-like observer can be designed for the obtained state affine system.     

<Superscript>252</Superscript>Cf-based generator of radioactive xenon isotopes

A generator of Xe radionuclides was developed. These isotopes are required to calibrate automatic installations used for determining noble gases at international stations of radionuclide monitoring. The results of purging a generator containing 0.1 μg of ²⁵²Cf are reported. Original Russian Text Yu.V. Dubasov, N.V. Skovorodkin, E.I. Biryukov, 2007, published in Radiokhimiya, 2007, Vol. 49, No. 3, pp. 262–263.     

The behavior of a cloud of emissions of high moisture content in the surface layer of the atmosphere

The propagation in the atmosphere of instantaneous emissions which largely consist of water vapor is treated in a three-dimensional formulation. The regularities are studied of the evolution of the hydrodynamic, concentration, and temperature fields depending on the parameters which define the state of the atmosphere (temperature and humidity), as well as on the temperature and moisture content of the cloud of emissions.     

Certain regularities of the kinetics of drying of moist materials

A method for calculating the kinetics of drying under the conditions of continuous variation in the Rehbinder number in the period of decreasing drying rate is considered. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 4, pp. 143–146, July–August, 2007.