23,601 research outputs found
The anodic behavior of zinc in aqueous salt solutions
The increasing demand for protective metals as coatings and non-corrosive alloys has caused extensive research on the fundamental behavior of metals in corrosive media. The problem of controlling the destructive process of metallic corrosion still exists and becomes urgent in this space age. The desirablity of metals such as beryllium, magnesium, and zinc in air frame and space structural units, because of their high strength to weight ratio, has been responsible for the considerable progress in their technology in recent years.
The basic mechanism of the anodic dissolution of metals such as zinc, cadmium, and magnesium in salt solution is not completely known. Many mechanisms have been proposed by different investigators but evidence is still lacking which would allow one to draw reliable conclusions and to explain the discrepanies which often arise between coulometric data and the weight loss of the metal electrodes in certain salt solutions.
The study of the influence of anions as well as cations on the anodic behavior of zinc undergoing dissolution might give an insight into the basic mechanism of metallic corrosion and the type of substances needed for corrosion inhibition.
The purpose of this investigation was to obtain a mechanism for the anodic dissolution of zinc that would relate the rate of dissolution, the anodic current density, the influence of anions, and other parameters to the observed behavior --Introduction, pages 1-2
Properties of Microlensing Central Perturbations by Planets in Binary Stellar Systems under the Strong Finite-Source Effect
We investigate high-magnification events caused by planets in wide binary
stellar systems under the strong finite-source effect, where the planet orbits
one of the companions. From this, we find that the pattern of central
perturbations in triple lens systems commonly appears as a combination of
individual characteristic patterns of planetary and binary lens systems in a
certain range where the sizes of the caustics induced by a planet and a binary
companion are comparable, and the range changes with the mass ratio of the
planet to the planet-hosting star. Specially, we find that because of this
central perturbation pattern, the characteristic feature of high-magnification
events caused by the triple lens systems appears in the residual from the
single-lensing light curve despite the strong finite-source effect, and it is
discriminated from those of the planetary and binary lensing events and thus
can be used for the identification of the existence of both planet and binary
companion. This characteristic feature is a simultaneous appearance of two
features. First, double negative-spike and single positive-spike features
caused by the binary companion appear together in the residual, where the
double negative spike occurs at both moments when the source enters and exits
the caustic center and the single positive spike occurs at the moment just
before the source enters into or just after the source exits from the caustic
center. Second, the magnification excess before or after the single
positive-spike feature is positive due to the planet, and the positive excess
has a remarkable increasing or decreasing pattern depending on the source
trajectory.Comment: 12 pages, 3 figures, accepted for publication in Ap
The anodic dissolution of cadmium in aqueous solution
The increasing importance of prevention of corrosion in industry has stimulated extensive studies on the fundamental behavior of metals in corrosive media.
The basic mechanism of the anodic dissolution of metals such as cadmium, magnesium, and zinc in salt solutions is not completely known. Several mechanisms have been proposed by different investigators, but evidence is still lacking to draw unquestionable conclusions to explain the discrepancies which often arise between coulometric data and weight loss of metal electrodes in certain salt solutions.
The purpose of this investigation was to obtain experimental data for anodic dissolution of cadmium in various electrolytes and to arrive at a mechanism consistent with the results --Introduction, page 1
The Effects of Using Expressive Intervention in Group Counseling on Acculturative Stress and Depressive Symptoms among Korean Immigrant Women in South and Central Texas :a n experimental study
This study evaluated the relationship between acculturative stress and depressive symptoms in Korean immigrant women and evaluated the use of expressive group counseling interventions for these women\u27s acculturative stress and depressive symptoms. Participants were randomly assigned to the intervention or control group. The intervention group received a total of four sessions of expressive group counseling interventions while the control group was asked to color pictures at home. Pearson correlations found statically significant relationships between acculturative stress and depressive symptoms in Korean immigrant women. The results of a one-way analysis of covariance (ANCOVA) indicated no statistically significant difference in the effect of expressive group counseling on the acculturative stress between the intervention and control groups. However, ANCOVA indicated a statistically significant difference in the effect of expressive group counseling on the depressive symptoms between the intervention and control groups
Asian perspectives on human rights and trade-off thesis : focus on South Korea
The primary objective of this study is to elucidate the nature of the Asian concept of human rights and to examine the interrelation between the process of economic growth and contingent human rights policies, using South Korea as a case study.
In the aftermath of the Cold War, several East Asian states in particular mounted a challenge to Western beliefs about human rights. Based on a successful economic growth and on the Confucian logic inherent in their tradition. East Asian states sought to redefine the concepts of human rights by questioning the applicability of universal human rights in different cultural, economic and socio-political settings.
Such an Asian concept of human rights has been supported for decades by several East Asian authoritarian leaders including those of Singapore, China, Indonesia, Malaysia, and the former ones of South Korea. In its most basic version, this special concept holds that economic development has to precede the full flowering of political and civil rights; that East Asians place greater value on the harmony of the community than on individual freedoms; and that individual states should be able to interpret international standards on human rights in accordance with their history, culture, political system, and level of economic development. These arguments are often labeled soft authoritarianism or Asian-style democracy.
The logic of Asian style democracy has been used by Asian repressive states to support the trade-off proposition: that a certain degree of authoritarianism is necessary to make the hard political and economic decisions that produce a state\u27s spectacular growth, and that such growth will facilitate the promotion of human rights.
However, in recent decades the history of human rights in South Korea offers no promise or proof that civil and political rights will be extended to citizens upon the realization of economic development goals. Authoritarian leaders have justified their failure to respect human rights not only as a sacrifice necessary to ensure the successful development of their economic growth strategy, but also as essential for the maintenance of law and order.
Basing itself on an understanding of Asian perspectives on human rights and on human rights practices characteristic of modem Korean history, this study concludes that if the economic growth of a country does not facilitate the realization of human rights after the country reaches a certain level of economic development, then various restrictions on human rights cannot be justified in the name of economic growth, and that human rights, a critical factor of desirable democracy, carmot be pushed aside until economic development is consolidated. In the same context, a country\u27s economic policies should promote the rule of law and not the political interests of abusive governments
Sustained and Transient Reward Effect on Cognitive Control in Schizophrenia: The Relevance of Negative Symptoms
Schizophrenia (SCZ) is characterized by severe cognitive impairments and amotivation, generally referred to as negative symptoms, including anhedonia and/or avolition. Amotivation tends to exist in prodromal patients and persist over the illness course regardless of successful antipsychotic medications, which are known to reduce positive symptoms, including hallucination and delusions (e.g., (Horan, Blanchard, Clark, & Green, 2008; Tarbox et al., 2013). Importantly, amotivation is a promising predictor for later social functioning in SCZ, even after accounting for patients\u27 cognitive impairments (e.g., (Evensen et al., 2012; Faerden et al., 2010). Despite this crucial impact on functioning outcome in SCZ, to date, no study has systematically investigated neural mechanism underlying amotivation in SCZ.
To date, it has been well documented that many of cognitive impairments in SCZ may reflect a core deficit of non-emotional context processing, supported by the dorsolateral prefrontal cortex (DLPFC), and defined by the ability to maintain non-emotional context information necessary to regulate upcoming behavioral response towards goal-directed behavior (e.g., (Cohen, Barch, Carter, & Servan-Schreiber, 1999). Recent evidence from both animal and healthy human neuroimaging work suggests that the DLPFC plays a crucial role in representing and integrating reward-related context information. However, it has been unexplored whether individuals with SCZ can represent and integrate reward-related contextual information to modulate cognitive control function implicated in the DLPFC.
Thirty-six individuals with SCZ and twenty-seven healthy controls (HC) underwent behavioral and fMRI data collection at 3Tsela while performing a modified response conflict processing task under two contexts, that is, no-reward baseline and reward contexts. Participants first performed baseline conditions without any knowledge regarding the future potential for incentives (Baseline-Context; BCXT). Each trial started with a baseline cue, XX that was pre-instructed to participants as being irrelevant to the task. After each cue, XX, either a house or building picture (with overlaid words that are either congruent or incongruent) was presented to each participant one at a time. The job of the task was to categorize each picture as either a house or a building by pressing a certain button while ignoring the overlaid word. Following the baseline condition, participants performed additional reward blocks on which they were told that they could win money on some trials by performing fast (faster than their median correct reaction times (RT) in the baseline and accurately). Each trial was then preceded either by a 20 ) versus RCXT (cued by XX ) within reward blocks. Importantly, by employing a mixed state-item fMRI design, I investigated both sustained (block-based) context-dependent and transient (trial-by-trial) reward-related cue activity at both behavioral and neural levels
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