Vaccines against endogenous hormones: a possible future tool in animal production

Vaccines have been widely used by the livestock industry to control and prevent disease. New technologies now permit development of vaccines against hormones that control reproduction, growth, and lactation in domestic farm animals. Results of research projects studying passive and active immunization against such hormones as estrogen, testosterone, LH, FSH, and somatotropin have demonstrated that reproductive efficiencies and growth can be altered through vaccination. Although immunizations against most of the hormones studied have proven effective in most cases, there remain problems related to longevity, consistency, and efficiency of response both within and between animals. When these areas have been clearly defined for individual hormones, standardized immunization regimens can be developed that will optimize antibody production in the animal, thus providing the animal agriculture industry with a powerful and profitable production tool.     

QoS control versus generous dimensioning

As the world of telecommunications embraces IP as the route to truly converged networks there are, for pioneering national telecommunications operators, difficult engineering requirements to address — in particular, how to deliver high-quality session-based services over a connectionless infrastructure. The falling price of commodity bit transport leads some to suggest that simply providing high levels of capacity will be enough to provide effective quality in the ‘new wave’ networks, and that sophisticated approaches, such as explicit bandwidth reservation, are an expensive luxury. We discuss the implications of operating a network under the two very different paradigms of QoS control (bandwidth reservation under connection control) and generous dimensioning, focusing at first on a pure PSTN replacement, before considering the implications for a true, converged multiservice platform. We conclude that these two approaches give rise to different services. In an increasingly competitive world we might choose either approach for different commercial reasons, but we should not be misled into believing that generous dimensioning gives us the same service as QoS control.     

车内线缆的高空核电磁脉冲响应分析

复杂电磁环境中的车载电子设备受制于高空核电磁脉冲的威胁,其内置线缆的电磁效应与防护决定了特种车辆的生存能力及性能发挥。文中采用基于FTDT算法的电磁仿真软件CST,建立了车辆壳体的电磁模型以及车辆内置线缆布局模型,并仿真分析了车内线缆的高空核电磁脉冲电流电压响应。仿真结果表明,双绞线上响应电压较大而响应电流较小;同轴线的响应电压较小响应电流较大。有屏蔽体的线缆在HEMP照射时的响应电压电流和无屏蔽体时相比显著减小。但是,实际车辆壳体存在孔缝,响应电压电流的在部分频点产生谐振,导致电压电流出现较大值。文中的仿真分析结果对车载电子设备的电磁脉冲防护具有一定的实际工程意义。     

A Novel Blocking Technology for Improving the Short-Channel Effects in Polycrystalline Silicon TFT Devices

An original blocking technology is proposed for improving the short-channel characteristics of polycrystalline silicon thin-film transistors (poly-Si TFTs). In particular, two types of modified devices called poly-Si TFT with block oxide and poly-Si on partial insulator (POPI)-TFT are designed for the first time in this field to enhance device performance. The proposed TFT structures can significantly reduce short-channel effects when compared with a thick source/drain (S/D) poly-Si TFT (i.e., the fully depleted TFT). In addition, an ultrathin (UT) S/D structure (UT-TFT) is designed to verify that the block oxide TFT devices do achieve improved performance without needing the thin active layers and ultrashallow junction depth. Also, the POPI-TFT is found to reduce the thermal instability through its natural body-tied scheme.     

Low‐Temperature Superionic Conductivity in Strained Yttria‐Stabilized Zirconia

Very high lateral ionic conductivities in epitaxial cubic yttria‐stabilized zirconia (YSZ) synthesized on single‐crystal SrTiO₃ and MgO substrates by reactive direct current magnetron sputtering are reported. Superionic conductivities (i.e., ionic conductivities of the order ～1 Ω^?1cm^?1) are observed at 500 °C for 58‐nm‐thick films on MgO. The results indicate a superposition of two parallel contributions – one due to bulk conductivity and one attributable to conduction along the film–substrate interface. Interfacial effects dominate the conductivity at low temperatures (<350 °C), showing more than three orders of magnitude enhancement compared to bulk YSZ. At higher temperatures, a more bulk‐like conductivity is observed. The films have a negligible grain‐boundary network, thus ruling out grain boundaries as a pathway for ionic conduction. The observed enhancement in lateral ionic conductivity is caused by a combination of misfit dislocation density and elastic strain in the interface. These very high ionic conductivities in the temperature range 150–500 °C are of great fundamental importance but may also be technologically relevant for low‐temperature applications.     

Study of Morphological Defects on Dual-Band HgCdTe on CdZnTe

HgCdTe dual-band epitaxial layers on lattice-matched CdZnTe substrates often have morphological defects. These defects, unlike normal void and microvoid defects, do not contain a polycrystalline core and, therefore, do not offer a good contrast for observation using optical and electron microscopes. This paper reports a way of identifying these defects by using a Nomarski optical microscopy image overlay on focused ion beam microscopy images for preparation of thin cross-sectional foils of these defects. Transmission electron microscopy was used to study the defect cross-sections to identify the origin and evolution of the morphological defects and their effect on the epitaxial layer. This paper reports cross-sectional analysis of four morphological defects of different shape and size.     

A methodology for designing,modifying, and implementing Fourier transform algorithms on various architectures

Fourier transform algorithms are described using tensor (Kronecker) products and an associated class of permutations. Algebraic properties of tensor products and the related permutations are used to derive variants of the Cooley-Tukey fast Fourier transform algorithm. These algorithms can be implemented by translating tensor products and permutations to programming constructs. An implementation can be matched to a specific computer architecture by selecting the appropriate variant. This methodology is carried out for the Cray X-MP and the AT&T DSP32.This work was performed at the Center for Large Scale Computation, Suite 400, 25 West 43rd Street, New York, New York 10036, USA, and was supported by a grant from DARPA/ACMP.     

Monolithic two-dimensional GaAs/AIGaAs laser arrays fabricated by chlorine lon-beam-assisted micromachining

Chlorine ion-beam-assisted etching (IBAE) has been used to micromachine laser facets and deflecting mirrors for monolithic two-dimensional GaAs/AIGaAs laser arrays. Three laser cavity/deflector designs have been successfully implemented. The first utilizes a parabolic deflecting mirror to directly focus the laser radiation; the second consists of a folded cavity with a vertical facet, a top surface facet, and an internal 45° reflector; and the third has a folded cavity with an internal Al_0.2Ga_0.8As/Al_0.8Ga_0.2As dielectric mirror stack and a top surface facet formed in a single etch step with two internal 45° reflectors. The parabolic deflecting mirrors are currently modeled forf- 0.8 collection efficiency, making the first design attractive in incoherent arrays for high-power applications such as pumping Nd:YAG lasers. The other two structures are of interest for incoherent or coherent arrays used in high- and medium-power applications, since the top surface facets can easily be antireflection coated. The design with a dielectric mirror stack is particularly simple to fabricate.