Influences of /spl delta/-doping position on the characteristics of SiGe-Si DCFETs

SiGe-Si doped channel field-effect-transistors with different positions of /spl delta/ layers in SiGe wells have been proposed and fabricated. High forward gate to drain turn-on voltage (>0.87 V) and reverse breakdown voltage up to 25 V was obtained for center and bottom /spl delta/-doped channel devices. For device structures with the same 1/spl times/100 /spl mu/m/sup 2/ gate, center /spl delta/-doped channel device display the best dc maximum extrinsic transconductance of 22.1 mS/mm. Compared with conventional Si-SiGe MODFETs, center /spl delta/-doped channel device exhibits improved gate voltage swings as wide as 3 V due to the better carrier confinement and the absence of parallel conduction, which is promising to provide an additional degree of freedom for Si-based device applications.     

Time and cost effective methods for testing chemical resistance of aluminium metallic pigmented powder coatings

Polyester based powder coatings containing different types of aluminium metallic flake pigments have been investigated with respect to their chemical stability in acid environments. The metallic flakes are made chemically stable by covering them in silica. The degree of silica coverage and the silica morphology are far more important for the chemical stability of the pigments than the silica thickness. The acid resistance of the final powder coating is found to depend on the pigment embedment depth, on the chemical composition and morphology of the powder coating, and on the silica coating of the pigment. The latter being the single most important factor in our study.     

A new scheme for ID‐based cryptosystems and signatures

Abstract

This paper proposes a new ID‐based cryptographic scheme for implementing public‐key cryptosystems and signatures. Instead of generating and publishing a public key for each user, the ID‐based scheme permits each user to choose his name or network address as his public key. This eliminates the need of a large public‐file and the exchange of private or public keys. The major advantage of the ID‐based cryptosystems is that the number of users can be exteneded to t*L users without decreasing the system security when users conspire, where L is the number of the system's secrets and t is the number of factors in p ‐ 1.     

An interdisciplinary and systems-based evaluation of academic programs: Bovine mastitis-related veterinary research, education and outreach

An interdisciplinary and systems-oriented approach for evaluation of academic programs was explored in veterinary research, education and extension in the context of prevention of bovine mastitis. Bibliometric-based document analysis and observation methods were used to assess disciplinary contents of veterinary research and graduate education theses, and New York State dairy farmers' adoption rate of selected veterinary recommendations (bacteriological testing of raw milk, “closed herds”, and three hygiene-related practices). Findings indicated that: a) the veterinary extension literature was lower in output and less differentiated in disciplinary content than that of the agricultural counterpart; b) three disciplines accounted for 85% of all theses major contents; and c) 39.7% of New York dairies requested bacteriological testing, 50% of investigated dairies had “closed herds” and at least 9.4% of those did not adopt all the hygiene-related practices. Context-specific recommendations are proposed. It is concluded that this evaluation approach may facilitate policy analysis, program development and may be applicable to other academic settings.     

Oxygen plasma flow properties deduced from laser-induced fluorescence and probe measurements

Estimation of the local dissociation degree and the local mass-specific enthalpy of a pure oxygen plasma flow determined mainly from laser-induced fluorescence measurements are reported. Measurements have been conducted for several generator parameters in an inductively heated plasma wind tunnel. Additional probe measurements of total pressure together with the deduced translational temperature are used to estimate the local mass-specific enthalpy. For a reference condition, full dissociation has been measured. The measured translational temperature of atomic oxygen for this condition is T = 3500 K. Subsequently, the local mass-specific enthalpy has been derived using these local density and temperature measurements. For the reference condition the estimated value of h = 27 MJ/kg is in good agreement with the probe measurements and results from diode laser absorption spectroscopy.     

The effect of vaccination against Mycoplasma hypopneumoniae in pig herds with a continuous production system

An inactivated Mycoplasma hyopneumoniae vaccine was evaluated in five pig herds clinically infected with enzootic pneumonia and practising a continuous production system in the growing/finishing unit. In each herd, a vaccinated and control group of approximately 47 pigs each were individually monitored from birth until slaughter. Vaccinated pigs received the first dose at about 1 week of age and the second approximately 3 weeks later. During all production stages, an equal number of vaccinated and control pigs was present in the same pen. Both groups were compared with respect to zootechnical parameters (major variables) and by means of serological, pathological, and bacteriological parameters (ancillary variables). Daily weight gain was improved by 14 gr/day during the period from 8 days of age until slaughter (P = 0.0486) and by 25 gr/day during the growing/finishing period (P = 0.0067). Mortality rate, and the costs for curative medication were not significantly improved by vaccination. The results of the ancillary variables are presented and discussed.     

An Ideal Multi-secret Sharing Scheme Based on Connectivity of Graphs

Secure communication has become more and more important for many modern communication applications. In a secure communication, every pair of users need to have a secure communication channel (each channel is controlled by a server) In this paper, using monotone span programs we devise an ideal linear multi-secret sharing scheme based on connectivity of graphs. In our proposed scheme, we assume that every pair of users, \(p\) and \(q\) , use the secret key \(s_{pq} \) to communicate with each other and every server has a secret share such that a set of servers can recover \(s_{pq} \) if the channels controlled by the servers in this set can connect users, \(p\) and \(q\) . The multi-secret sharing scheme can provide efficiency for key management. We also prove that the proposed scheme satisfies the definition of a perfect multi-secret sharing scheme. Our proposed scheme is desirable for secure and efficient secure communications.     

Engineered CNT Support for Selective Hydrogenation Reactions

Pt catalyst supported on a novel engineered CNT support which preserves the advantageous morphology and porosity of as-made CNTs agglomerates exhibits lower C?CCl hydrogenolysis activity in hydrogenation of p-chloronitrobenzene than commercial Pt catalyst supported on activated carbon. This is attributed to the open ended pore structure and meso/macro porosity of the CNT support.