Characteristics of Corona-Charged PET Sandwich Electrets

2005 ◽  
Vol 480-481 ◽  
pp. 123-128 ◽  
Author(s):  
L.S. Tai ◽  
Y.W. Wong ◽  
Y.M. Poon ◽  
F.G. Shin

Polyethylene terephthalate (PET) is one of the major electret materials which has been studied and widely used in charge storage applications for a long time. The homo-charge and hetero-charge formation responsible for the electret effect of PET can be explained by the dipolar polarization, space charge separation and charge injection respectively as a result of contact poling or corona charging. These processes are also verifiable from studies of surface charges and thermally stimulated depolarization current (TSDC) of the PET films. Now consider a stack of PET films charged under the same condition as a single film. It would be intuitively expected that the electret effects of the individual films of the stack should be different due to their different positions in the stack. However, in a recent study on charged PET stacks, it was found that the electret effects of the individual films are quite similar. The surface charges of the individual films are about the same and they sum to make same total as a single charged PET film. On the other hand, the TSDC thermograms of individual films show similar characteristics in the thermal relaxation processes where homo- and hetero- charge effects are still observed. From the TSDC results, especially for the film in the middle of a triple layer sandwich, it shows clearly dipolar polarization and charge injection related peaks. These findings agree with the results of surface charge studies of the individual films.

2019 ◽  
Vol 26 (38) ◽  
pp. 6942-6969 ◽  
Author(s):  
Federico Mucci ◽  
Maria Teresa Avella ◽  
Donatella Marazziti

Background: Attention deficit hyperactivity (ADHD) disorder is a neurodevelopmental disorder characterized by inattention, hyperactivity, disruptive behaviour, and impulsivity. Despite considered typical of children for a long time, the persistence of ADHD symptoms in adulthood gained increasing interest during the last decades. Indeed, its diagnosis, albeit controversial, is rarely carried out even because ADHD is often comorbid with several other psychiatric diosrders, in particular with bipolar disorders (BDs), a condition that complicates the clinical picture, assessment and treatment. Aims: The aim of this paper was to systematically review the scientific literature on the neurobiological, clinical features and current pharmacological management of ADHD comorbid with BDs across the entire lifespan, with a major focus on the adulthood. Discussion: The pharmacology of ADHD-BD in adults is still empirical and influenced by the individual experience of the clinicians. Stimulants are endowed of a prompt efficacy and safety, whilst non-stimulants are useful when a substance abuse history is detected, although they require some weeks in order to be fully effective. In any case, an in-depth diagnostic and clinical evaluation of the single individual is mandatory. Conclusions: The comorbidity of ADHD with BD is still a controversial matter, as it is the notion of adult ADHD as a distinct nosological category. Indeed, some findings highlighted the presence of common neurobiological mechanisms and overlapping clinical features, although disagreement does exist. In any case, while expecting to disentangle this crucial question, a correct management of this comorbidity is essential, which requires the co-administration of mood stabilizers. Further controlled clinical studies in large samples of adult ADHD-BD patients appear extremely urgent in order to better define possible therapeutic guidelines, as well as alternative approaches for this potentially invalidating condition.


1982 ◽  
Vol 14 (9) ◽  
pp. 1175-1193 ◽  
Author(s):  
R Herz

The question of the extent to which the concrete physical environment allows, causes, or even forces certain forms of behaviour to occur has been excluded from social sciences literature for a long time. More recent studies from environmental psychology show that the built environment, filtered by subjective perceptions, very probably influences the experience and actions of individuals. Town planning and transport planning is orientated towards the needs, demands, or simply the observed behaviour of social groups, segments of the population, and target groups of individuals. However, at this level the evidence about whether a spatiospecific determinant should be added to the sociodemographic, sociocultural, or socioeconomic determinants is very inconclusive. This paper investigates the influence of certain types of area on behaviour, and uses about 70000 weekday records at the level of differentiated groups of people. Everyday behaviour of the groups is quantified by their time budgets and daily programmes with broad groupings of out-of-house activities as well as various indicators of transport mobility. This study shows that with given characteristics of the individual and his household a series of behavioural parameters does not vary in space and thus these parameters can be used as input for behaviourally orientated transport demand models and transferred from one planning area to another.


Geophysics ◽  
1965 ◽  
Vol 30 (3) ◽  
pp. 363-368 ◽  
Author(s):  
T. W. Spencer

The formal solution for an axially symmetric radiation field in a multilayered, elastic system can be expanded in an infinite series. Each term in the series is associated with a particular raypath. It is shown that in the long‐time limit the individual response functions produced by a step input in particle velocity are given by polynomials in odd powers of the time. For rays which suffer m reflections, the degree of the polynomials is 2m+1. The total response is obtained by summing all rays which contribute in a specified time interval. When the rays are selected indiscriminately, the difference between the magnitude of the partial sum at an intermediate stage of computation and the magnitude of the correct total sum may be greater than the number of significant figures carried by the computer. A prescription is stated for arranging the rays into groups. Each group response function varies linearly in the long‐time limit and goes to zero when convolved with a physically realizable source function.


Author(s):  
Л.Д. Александрова ◽  
Р.А. Богачева ◽  
Т.А. Чекалина ◽  
М.В. Максимова ◽  
В.И. Тимонина

Изучение возможностей мозга для повышения качества обучения находится в центре внимания педагогической науки уже много лет. Развитие цифровизации позволило использовать в исследованиях специальное оборудование, с помощью которого можно оценивать и контролировать работу мозга, развивать умственные способности, познавательные функции и т. п. Нейротехнологии стали эффективным средством, позволяющим трансформировать образовательный процесс за счет подбора специального учебного контента с учетом индивидуальных особенностей обучающихся. Вместе с тем возникает необходимость в конкретизации терминологии и определении актуальных направлений исследований в данной области. For a long time, the study of the brain capabilities for the improvement of the quality of education has been an urgent direction in pedagogical science. Due to the development of digitalization, new areas of research have emerged related to the use of special equipment that makes it possible to assess and control brainwork, develop mental abilities, cognitive functions, etc. One of them is neurotechnology, which is an effective means of transforming the educational process: it offers educational content based on the individual characteristics of students. Thus, a need to concretize the terminology and determine the current research areas arises. The article aims to attempt to fill this gap with the help of a representative analysis of publications on neurotechnologies, as well as the essence of neuroeducation.


2004 ◽  
Vol 819 ◽  
Author(s):  
Irina V. Belova ◽  
Graeme E. Murch

AbstractWe address the problem of calculating the long-time-limit effective diffusivity in stable two- phase polycrystalline material. A phenomenological model is used where the high diffusivity interphase boundaries are treated as connected “coatings” of the individual grains. Derivation of expressions for the effective diffusivity with segregation is made along Maxwell lines. Monte Carlo simulation using lattice-based random walks is used to test the validity of the expressions. It is shown that for the case analysed the derived expressions for the effective diffusivity are in very good agreement with simulation results. The equivalent of the Hart equation is also derived. It is shown to be in poor agreement with simulation results.


1994 ◽  
Vol 29 (3) ◽  
pp. 249-272 ◽  
Author(s):  
Paul Cameron ◽  
William L. Playfair ◽  
Stephen Wellum

Although the U.S. Surgeon General characterized homosexual sex as “normal” and “healthy,” homosexuals and IV drug abusers have suffered disproportionately from the AIDS epidemic. Longevity is often utilized as a measure of health. How long did homosexuals live before the AIDS epidemic and how long do they live today? We examined 6,737 obituaries/death notices from eighteen U.S. homosexual journals over the past thirteen years and compared them to obituaries from two conventional newspapers. The obituaries from the non-homosexual newspapers were similar to U.S. averages for longevity: the median age of death of married men was seventy-five, 80 percent died old (65 or older); for unmarried men it was fifty-seven, 32 percent died old; for married women it was seventy-nine, 85 percent died old; for unmarried women it was seventy-one, 60 percent died old. For the 6,574 homosexual deaths, the median age of death if AIDS was the cause was thirty-nine irrespective of whether or not the individual had a Long Time Sexual Partner [LTSP], 1 percent died old. For those 829 who died of non-AIDS causes the median age of death was forty-two (41 for those 315 with a LTSP and 43 for those 514 without) and <9 percent died old. Homosexuals more frequently met a violent end from accidental death, traffic death, suicide, and murder than men in general. The 163 lesbians registered a median age of death of forty-four (20% died old) and exhibited high rates of violent death and cancer as compared to women in general. Old homosexuals appear to have been proportionately less numerous than their non-homosexual counterparts in the scientific literature from 1858 to 1993. The pattern of early death evident in the homosexual obituaries is consistent with the pattern exhibited in the published surveys of homosexuals and intravenous drug abusers. Homosexuals may have experienced a short lifespan for the last 140 years; AIDS has apparently reduced it about 10 percent. Such an abbreviated lifespan puts the healthfulness of homosexuality in question.


2021 ◽  
Vol 201 (3) ◽  
pp. 547-560
Author(s):  
D. N. Yuriev ◽  
G. V. Zhukovskaya

Research and commercial trawl catches of humpback shrimp Pandalus hypsinotus from the Tatar Strait (Japan Sea) in 2004–2020 were investigated, with bioanalysis of about 45 thousand specimens. Average timing of group molting, spawning, and eggs laying are determined, terms of gonads and eggs development are estimated. Prespawning and molting of the females occur between January-April, with the peaks in early February and middle February, respectively. All oviparous females have 30–40 days to lay eggs, and molt during 50–55 days; the peak of the eggs laying occurs in late June. The males molt in July-August, afterwards the largest individuals change gender and new intersexes are formed. The males have the second molting in October-December, with the peak in late November. In January, after finish of the males molting, a new annual reproduction cycle starts from the prespawning molting of females. Both vitellogenesis and embryogenesis are observed through the year, though females with developing gonads prevail from August to January (because of a long time span between winter and summer moltings while the egg carrying continued 15 months) but oviparous females — from February to July. The individual reproductive cycle of Pandalus hypsinotus in the Tatar Strait lasts 24 months, with 9 months of vitellogenesis (quick growth of gonads) and 15 months of embryogenesis. During the 2-year reproductive cycle, most of females pass through the following stages: i) gonads development (just after eggs laying) when almost all oviparous females (up to 95 % in May) have green gonads under carapace that corresponds to the stage of development «eggs laid — gonads weakly developed»; ii) summer molting from August when females lose hairs on pleopods and the gonads growth accelerates; iii) respawning in January-March (together with the firstly spawning intersexes, with slight delay of the latter); iv) initial developing of eggs during summer; v) stage of «eyed eggs» from December to March; and vi) eggs laying and molting from late March to late May; then the 2-year reproductive cycle repeats.


2011 ◽  
Vol 295-297 ◽  
pp. 1206-1210
Author(s):  
Yan Feng Guo ◽  
Xian Ping Ma ◽  
Yu Yan ◽  
Yun Gang Fu

The main feature of this article is the investigation on the influence of temperature, relative humidity, film thickness on permeability of PET packaging film, the analysis of perm-selectivity of the packaging films for oxygen gas and carbon dioxide gas, and the evaluation on experimental formulas of water vapor, O2 and CO2 gas permeating rates on the basis of gas molecular osmotic reaction kinetics and regression analysis. The comparison between experimental studies and calculation indicates that: (1) with increment of ambient temperature water vapor, O2 and CO2 permeating rate of PET films and PET/Al film also rise, and the logarithm of water vapor, O2 and CO2 gas permeating rates has linear relation with the reciprocal of thermodynamic temperature, and (2) the influence of relative humidity on water vapor permeating rate of PET film with thickness 12µm is the least, and that of PET film with thickness 20µm and PET/Al film with thickness 18µm is a little obvious. (3) The PET films hold remarkable perm-selectivity for O2 and CO2 gas, and CO2 gas permeating rate is about two times of O2 gas, yet O2 and CO2 gas permeating rates of PET/Al film are both very low and have small difference, so the PET/Al film has better barrier performance than the PET film.


2000 ◽  
Vol 07 (05n06) ◽  
pp. 571-575
Author(s):  
A. ICHIMIYA ◽  
K. HAYASHI

Isolated three-dimensional (3D) silicon mounds on the Si (111)(7×7) surface have been produced using the tip of a scanning tunneling microscope (STM) at temperatures between 700 K and 750 K. Thermal relaxation processes of the mounds have been investigated by a temperature-variable STM. The 3D mounds formed by the STM tip are like pyramids with certain facets for both surfaces. The indices of the main facets of the mounds on the Si (111) surface are {311}, and those of the small facets are {221} or {331}. Two types of pyramids are produced on the Si (111). The pyramids with a production probability of 75% are normal stacking at the interface between the mound and the substrate, and are called type U. For mounds with a production probability of 25% which are in the twin relation of the type U mounds, there is a stacking fault at the interface, and they are called type F. The formation energy of the stacking fault is estimated from the ratio of the production probability as 4.7 meV/Å2. The decay rate of the type F mounds is about three times larger than that of the type U ones. During decomposition of the type U mounds, the facets of the pyramid are split into two parts. For the type F mounds, the pyramids decay nearly layer by layer without splitting of the facets and step bunching.


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