A novel and precise time domain description of MOSFET low frequency noise due to random telegraph signals

Nowadays, random telegraph signals play an important role in integrated circuit performance variability, leading for instance to failures in memory circuits. This problem is related to the successive captures and emissions of electrons at the many traps stochastically distributed at the silicon-oxide (Si-SiO2) interface of MOS transistors. In this paper we propose a novel analytical and numerical approach to statistically describe the fluctuations of current due to random telegraph signal in time domain. Our results include two distinct situations: when the density of interface trap density is uniform in energy, and when it is an u-shape curve as prescribed in literature, here described as simple quadratic function. We establish formulas for relative error as function of the parameters related to capture and emission probabilities. For a complete analysis experimental u-shape curves are used and compared with the theoretical aproach

Synthesis of 2,4,6-triamino-1,3,5- trinitrobenzene

The 2,4,6-triamino-1,3,5-trinitrobenzene (TATB) is perhaps the most thermostable and insensitive explosive known. Its low sensibility to shock makes it suitable for military and civil applications. TATB application is done either alone or in combination with another high energetic material. This study aimed at reporting the review about many processes to produce TATB and the problems associated with them, as well as suggest techniques like Fourier Transform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC), which can be useful in the characterization of this energetic compound

Logarithmic behavior of degradation dynamics in metal--oxide semiconductor devices

In this paper the authors describe a theoretical simple statistical modelling of relaxation process in metal-oxide semiconductor devices that governs its degradation. Basically, starting from an initial state where a given number of traps are occupied, the dynamics of the relaxation process is measured calculating the density of occupied traps and its fluctuations (second moment) as function of time. Our theoretical results show a universal logarithmic law for the density of occupied traps $\bar{} \sim \phi (T,E_{F}) (A+B \ln t)$, i.e., the degradation is logarithmic and its amplitude depends on the temperature and Fermi Level of device. Our approach reduces the work to the averages determined by simple binomial sums that are corroborated by our Monte Carlo simulations and by experimental results from literature, which bear in mind enlightening elucidations about the physics of degradation of semiconductor devices of our modern life

The UK register of HIV seroconverters: Methods and analytical issues

A Register of HIV-infected persons who have had a negative antibody test within 3 years of their first antibody positive test (seroconverters) is being set up in the UK to monitor the distribution of times from HIV seroconversion to AIDS (the incubation period) and to death. It will also provide a national resource for use by those designing studies in this group of individuals. Clinicians caring for HIV-positive persons in Genito-Urinary Medicine, Infectious Disease and other departments throughout the UK were asked to participate by providing information on eligible subjects. Most laboratories undertaking HIV antibody testing were also contacted and asked to provide the name of the attending clinician for all seroconverters identified through the HIV laboratory reporting systems of the PHLS Communicable Disease Surveillance Centre (CDSC) and the Scottish Centre for Infection and Environmental Health (SCIEH) and for any other seroconverters known to them but not identified by CDSC or SCIEH. Data items sought for the Register include: sex, ethnic group, probable route of HIV transmission, annual CD4 counts, details of therapy and prophylaxis prescribed, AIDS-defining events and vital status. Follow up information is collected annually. Wherever possible, all seroconverters known to a clinic have been identified, whether currently alive or dead, either from clinic records or laboratory reporting or both. The objective is to establish and update a complete register of seroconverters on a long-term basis to provide reliable estimates of the incubation period on which future projections of AIDS cases in the UK can be made

Editorial, ou à guisa de um começo

International audienceVolume 1. Número 1. O início de uma caminhada. Esse é o número de abertura da Revista Observatório, publicado pelo Núcleo de Pesquisa e Extensão Observatório de Pesquisas Aplicadas ao Jornalismo e ao Ensino (OPAJE) da Universidade Federal do Tocantins (UFT). Mas, mesmo sendo a ‘abertura', não se trata de um começo, apenas. É o consolidar de uma caminhada realizada pelo OPAJE-UFT e seus pesquisadores desde sua criação em 2013, primeiro como Grupo de Pesquisa na plataforma dos Diretórios de Grupos de Pesquisa do CNPq, e, depois, em 2014, quando de sua aprovação como Núcleo de Pesquisa e Extensão pela própria universidade

Evaluation of nanoparticles in the performance of energetic materials

The addition of nanosized metal particles in propulsion systems such as solid and liquid propellants, hybrid propellant and ramjet motors has recently became a major focus of research. Significant increases in the burning velocity and in the specific impulse are some of the advantages of using nano-scale energetic materials in many different types of propulsion systems. Aluminum has been largely employed as a metallic additive in energetic materials, also in a recently new propulsion system (aluminum/ice propulsion, “Alice”), and some studies show that the advantages of using nanosized aluminum instead of microsized aluminum are facilitating the ignition of the systems and allowing better incorporation of the components in the formulations and improving its homogeneity. Some of the combustion processes that require high pressures and even higher temperatures can occur in moderate conditions due to the increase of the surface area of the reactants, in this case, the metallic additive

Use of benzoic acid for piglets

Um experimento foi conduzido com o objetivo de avaliar os efeitos da inclusão de ácido benzoico (Vevovitall®) na dieta sobre o desempenho e a morfologia intestinal do duodeno de leitões de 28 a 70 dias de idade. Foram utilizados 160 leitões Dalland × Penarlan desmamados aos 21 dias de idade, separados por sexo. O experimento foi dividido em fases pré-inicial 1 (28 a 35 dias de idade), pré-inicial 2 (36 a 46 dias de idade) e fase inicial (47 a 70 dias idade). Utilizou-se o delineamento experimental tipo blocos ao acaso com 5 tratamentos, cada um com 8 repetições de 4 animais, totalizando 40 unidades experimentais. Foram utilizados quatro níveis de ácido benzoico (0; 0,25; 0,50 e 0,75%) e um tratamento testemunha com ácido fumárico. Abateram-se, aos 70 dias de idade, dois animais por repetição para coleta de amostras do duodeno e estudo da morfologia intestinal e um animal por repetição para estudo de lesões gástricas. Foram avaliadas as características de desempenho (ganho de peso, consumo de ração e conversão alimentar) para cada fase e para o período total. Como características morfológicas, foram avaliadas a altura das vilosidades, a profundidade de criptas e a relação altura de vilosidades/profundidade de criptas. Avaliou-se ainda a incidência de diarreia. No período de 28 a 70 dias, o uso de ácido benzoico influencia o desempenho de suínos, que neste estudo foi melhor os níveis de 0,50 e 0,75%, e reduz a incidência de diarreia. Animais alimentados com dietas contendo ácido benzoico apresentam maior altura de vilosidade e profundidade de criptas.An experiment was conducted with the objective of evaluating the effects of different levels of benzoic acid (Vevovitall) on the performance and intestinal morphology of the duodenum in piglets from 28 to 70 days of age. One hundred and sixty Dalland × Penarlan piglets weaned at 21 day old, separated by sex, were used. The experiment was divided into pre-initial 1 (28 to 35 days), pre-initial 2 (36 to 46 days) and initial (47 to 70 days) phases. A randomized complete block design was used with 5 treatments and 8 replications, totaling 40 experimental units. Four levels of benzoic acid (0, 0.25, 0.50 and 0.75%) were used and a control with acid fumaric in the diets. Two animals were slaughtered per replication at 70 days of age to collect duodenum samples to study the intestinal morphology and one animal per replication to study gastric lesions. The following characteristics were assessed: performance (weight gain, feed intake and feed conversion) for each phase and the entire period. The following were assessed as morphological characteristics the villous height, duodenum crypts depth and the villous height/duodenum crypt depth ratio. Diarrhea incidence was also evaluated. The use of benzoic acid improved performance and reduced diarrhea incidence of piglets from 28 to 70 days of age, with the best results obtained by using 0.50 and 0.75%. Animals fed with the diets containing benzoic acid presented greater villous height and crypt depth

Aesthetics appreciation of wood colour and patterns by colorimetry. Part 1. Colorimetry theory for the cielab system

The colorimetry theory for the CIELab system today allows us to compute the chromatic coordinates of the raw timber colour along the wood - chain industry. The wood industry is nd strongly behind in such areas. Progress in the wood appearance description by means of colour and pattern characteristics would be suitable to classify the wood. It would also help to match pieces of wood in furniture and inside the houses, to study the wood colour change in wood ageing by photodecoloration or by drying operations, and to improve wood colour variability