Noise modeling for RF CMOS circuit simulation

The RF noise in 0.18-/spl mu/m CMOS technology has been measured and modeled. In contrast to some other groups, we find only a moderate enhancement of the drain current noise for short-channel MOSFETs. The gate current noise on the other hand is more significantly enhanced, which is explained by the effects of the gate resistance. The experimental results are modeled with a nonquasi-static RF model, based on channel segmentation, which is capable of predicting both drain and gate current noise accurately. Experimental evidence is shown for two additional noise mechanisms: 1) avalanche noise associated with the avalanche current from drain to bulk and 2) shot noise in the direct-tunneling gate leakage current. Additionally, we show low-frequency noise measurements, which strongly point toward an explanation of the 1/f noise based on carrier trapping, not only in n-channel MOSFETs, but also in p-channel MOSFETs.     

A kinetic model for the acid-oxygen pressure leaching of Ni–Cu matte

A semi-empirical mathematical model for the acid-oxygen pressure leaching of Ni–Cu matte is presented, based on data from batch leaching experiments. The primary controlling factor in the leaching process is found to be galvanic inhibition of the more highly oxidized copper and nickel sulfide species by less oxidized species, particularly Ni alloy and Ni₃S₂. The leaching rate of many species is greatly reduced by the presence of one or both of these phases, and others will not commence leaching until neither is present. The mathematical model is based on first-order chemical reaction controlled rate expressions, as the reactions occurring are electrochemical in nature. Mass transfer effects are included only empirically. Some possibly diffusion-related phenomena are noted, although the model is not extended to incorporate these effects on a fundamental level. The model is verified and extended by the inclusion of several different factors that were tested experimentally. The effects of variations in O₂ flow rate and partial pressure, initial particle size, reaction pulp density and initial acid concentration were all studied, and included in the model. Variations in O₂ flow rate and partial pressure are found to affect the reaction rates via the dissolved oxygen concentration in the solution phase.     

Ethernet-based passive optical local-area networks for fiber-to-the-desk application

We introduce optical local-area network (LAN) architectures based on multimode optical fiber and components, short wavelength lasers and detectors, and the widely used fast Ethernet protocol. These architectures are designed to lower the costs associated with passive optical LAN implementation. Further reduction in overall cost is achieved through decreased network downtime, lower maintenance cost, extended geometrical spans, and larger headroom for future capacity increase. These optically transparent networks represent a novel approach for implementing fiber-to-the-desk.     

Structure determination of CaMgGeO4

The crystal structure of CaMgGeO₄ is described. CaMgGeO₄, M_r = 200.9, orthorhombic, Pnam, A = 11.285(5) Å, B = 5.016(2) Å, C = 6.435(2) Å, V = 364.36 ų, Dx = 3.664 Mg/m³.λ(MoK_a = 0.71069 Å, F(000) = 384, room temperature, final R = 0.045 for 1752 observed reflections. The structure is isomorphous with CaMgSiO₄ (monticellite).     

Narcissism, sexual refusal, and aggression: Testing a narcissistic reactance model of sexual coercion.

Laboratory analog studies investigated the theory that narcissism and reactance contribute to causing rape. In Study 1, narcissism correlated positively with rape-supportive beliefs and negatively with empathy for rape victims. In Study 2, narcissists reported more enjoyment than other men of film depictions that presented consensual, affectionate activity followed by rape (but not in response to either affection or rape alone). In Study 3, narcissists were more punitive than other men toward a female confederate who refused to read a sexually arousing passage aloud to them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prognostic significance of color Doppler findings in head and neck tumors

This summary of the practice parameters describes the assessment, differential diagnosis, and treatment of children, adolescents, and adults who present with symptoms of attention-deficit/hyperactivity disorder. The rationales for specific recommendations are based on a review of the scientific literature and clinical consensus which is contained in the complete document. Assessment includes clinical interviews with the child and parents and standardized rating scales from parent and teachers. Testing of intelligence and academic achievement is usually required. Comorbidity is common. The cornerstones of treatment are support and education of parents, appropriate school placement, and psychopharmacology. The primary medications are psychostimulants, but antidepressants and alpha-adrenergic agonists are used in special circumstances. Other treatments such as behavior modification, school consultation, family therapy, and group therapy address remaining symptoms.     

One hundred years of orthopedics in the Netherlands. I. Introduction

One hundred years ago, on 1 May 1898, the Netherlands Orthopaedic Association was founded. This was prompted by the view that general surgeons paid insufficient attention to the treatment of the locomotor system; they were permitted to join the new association, however, at any rate until 1947. It was especially in the last 30 years that orthopaedic surgery underwent major changes. The most striking novelty was arthroplastic surgery. There have also been developments in the treatment of spinal abnormalities, rheumatological surgery, sports medicine, oncology and traumatology.