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Search Results: 1 - 10 of 156697 matches for " K. Han "
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A Development of the dust deposition in the area surrounding the SMZ, a.s., Jel ava plant
Hanèu?ák Jozef
Acta Montanistica Slovaca , 2000,
Abstract: The area of Jel ava Lubeník ranks among the eight excessively polluted areas registered in Slovakia. The main cause of this situation is a hundred years of existence of the exploitation and processing of magnesite. The SMZ, a.s. Jel ava is currently the biggest Slovak producer of brick and steel magnesite-based clinkers. The technological procedures used to process the raw material represent the main source of solid polluting substances as well as the primary dustiness in the area surrounding the plant. The negative visual look of the surrounding country has its origin in the past, when a 25-times higher quantity of the currently produced solid emissions was released into the air in some years, while the current value of the pollution does not exceed 200 tons per year. The devastated, deforested and degrassed surfaces of the area surrounding the plant and roads became a significant source of secondary dustiness in the given area.Since 1994 úGt SAV Ko ice in co-operation with SMZ, a.s. Jel ava has been focusing on the monitoring of solid emissions in the form of dust deposition. 18 sampling points situated in the vicinity of the plant, mainly in surrounding villages and city Jel ava were originally built for the purpose of sampling the dust deposition. The samples were taken monthly , analysed by the gravimetric method and the samples of dust deposition was determined in g.m-2.(30 days)-1. To analyse all samples, they were cumulated for a certain period and then the selected elements were analysed using the AAS method. The results of the dust deposition were averaged for each individual year of the period from 1996 to 1999 to make a better interpretation of the results. The results of the chemical analysis represent an average for a given period. The main component of the dust deposition, i.e. MgO is stated as an average value in individual years.The processed results from 1996 to 1999 show a decreasing trend in the total dust deposition in all localities, except for 1999, when a slight increase was observed in some localities. This increase observed in the most exposed sampling points in the vicinity of the main primary sources did not achieve the value recorded in 1996. In addition to the localities in the vicinity of the plant, the highest hygienic admissible dust deposition [12.5 g.m-2.(30 days)-1] was sporadically exceeded on the places located in the populated zone of Jel ava, especially during summer dry seasons. The decrease observed in 1999 in the case of the most exposed places in the vicinity of the plant can be caused by an increase in the
Psychiatric Aspects of Multiple Sclerosis and Recent Treatment Approaches
Aysu K. T?HAN
N?ropsikiyatri Ar?ivi , 2008,
Abstract: Multiple sclerosis (MS) is a chronic demyelinating disorder characterized by multiple neuropsychiatric symptoms related to multifocal lesions in the white matter of the central nervous system (CNS). MS disrupt the conductance of action potential by effecting myelin coats of the neurons. Thus, many neurological symptoms and consequently disability may occur. Psychiatric disorders and symptoms accompanies in the course of MS as primary or secondary reasons. Mood disorders; especially depression, psychiatric disorders, chronic fatigue and cognitive impairment decrease the patient’s quality of life. Clinical course become more complicated because of the neurological, cognitive and psychiatric symptoms co-occurrence. Multipl behavioral and affective alterations may arise due to location and extension of the plaques. Illness perception and the coping strategies may also effect life quality and consequently the prognosis. The treatment of MS includes corticosteroids and the immunosuppressive agents which have various psychiatric side effects. So management of MS patients requires a multidisciplinary and comprehensive approach. The purpose of this rewiev is the evaluation of psychiatric disorders and symptoms due to MS and its treatment and also their possible effects on clinical process, prognosis, patient’s compatibility, life quality depending on the actual literature. (Archives of Neuropsychiatry 2008; 45 Supplement: 37-43)
Ferromagnetic Spin Coupling as the Origin of 0.7 Anomaly in Quantum Point Contacts
K. Aryanpour,J. E. Han
Physics , 2008, DOI: 10.1103/PhysRevLett.102.056805
Abstract: We study one-dimensional itinerant electron models with ferromagnetic coupling to investigate the origin of 0.7 anomaly in quantum point contacts. Linear conductance calculations from the quantum Monte Carlo technique for spin interactions of different spatial range suggest that $0.7(2e^{2}/h)$ anomaly results from a strong interaction of low-density conduction electrons to ferromagnetic fluctuations formed across the potential barrier. The conductance plateau appears due to the strong incoherent scattering at high temperature when the electron traversal time matches the time scale of dynamic ferromagnetic excitations.
Index theorem, spin Chern Simons theory and fractional magnetoelectric effect in strongly correlated topological insulators
K. -S. Park,H. Han
Physics , 2011,
Abstract: Making use of index theorem and spin Chern Simons theory, we construct an effective topological field theory of strongly correlated topological insulators coupling to a nonabelian gauge field $ SU(N) $ with an interaction constant $ g $ in the absence of the time-reversal symmetry breaking. If $ N $ and $ g $ allow us to define a t'Hooft parameter $ \lambda $ of effective coupling as $ \lambda = N g^{2} $, then our construction leads to the fractional quantum Hall effect on the surface with Hall conductance $ \sigma_{H}^{s} = \frac{1}{4\lambda} \frac{e^{2}}{h} $. For the magnetoelectric response described by a bulk axion angle $ \theta $, we propose that the fractional magnetoelectric effect can be realized in gapped time reversal invariant topological insulators of strongly correlated bosons or fermions with an effective axion angle $ \theta_{eff} = \frac{\pi}{2 \lambda} $ if they can have fractional excitations and degenerate ground states on topologically nontrivial and oriented spaces. Provided that an effective charge is given by $ e_{eff} = \frac{e}{\sqrt{2 \lambda}} $, it is shown that $ \sigma_{H}^{s} = \frac{e_{eff}^{2}}{2h} $, resulting in a surface Hall conductance of gapless fermions with $ e_{eff} $ and a pure axion angle $ \theta = \pi $.
Dirac Quantization and Fractional Magnetoelectric Effect on Interacting Topological Insulators
K. -S. Park,H. Han
Physics , 2010,
Abstract: We use Dirac quantization of flux to study fractional charges and axion angles \theta in interacting topological insulators with gapless surface modes protected by time-reversal symmetry. In interacting topological insulators, there are two types of fractional axion angle due to conventional odd and nontrivial even flux quantization at the boundary. On even flux quantization in a gapped time reversal invariant system, we show that there is a halved quarter fractional quantum Hall effect on the surface with Hall conductance of p/4q e2/2h with p and q odd integers. The gapless surface modes can be characterized by a nontrivial Z2 anomaly emerged from the even flux quantization. It is suggested that the electron can be regarded as a bound state of fractionally charged quarks confined by a nonabelian color gauge field on the Dirac quantization of complex spinor fields.
Spin Relaxation in Single Layer and Bilayer Graphene
Wei Han,Roland K. Kawakami
Physics , 2010, DOI: 10.1103/PhysRevLett.107.047207
Abstract: We investigate spin relaxation in graphene spin valves and observe strongly contrasting behavior for single layer graphene (SLG) and bilayer graphene (BLG). In SLG, the spin lifetime ({\tau}s) varies linearly with the momentum scattering time ({\tau}p) as carrier concentration is varied, indicating the dominance of Elliot-Yafet (EY) spin relaxation at low temperatures. In BLG, {\tau}s and {\tau}p exhibit an inverse dependence, which indicates the dominance of Dyakonov-Perel spin relaxation at low temperatures. The different behavior is due to enhanced screening and/or reduced surface sensitivity of BLG, which greatly reduces the impurity-induced EY spin relaxation.
Depot Disulfiram Implantation and Wound Infection: A Case Report
Aysu K?vrak T?HAN,Deniz T?HAN,?lhan YARGI?
N?ropsikiyatri Ar?ivi , 2008,
Abstract: The efficacy of disulfiram has been well known for over 50 years in alcohol dependence management. If disulfiram is in the body, whenever the patient consumes alcohol, it causes accumulation of a toxic intermediate metabolite called acetald§ehyde and produces unpleasant side effects. However, for adequate efficacy, it must be taken per os daily. Therefore, the major difficulty of its usage is compliance of treatment. When patients are recommended to self administer drugs, most of them stop their treatment after a short time. An implantable, slow-release, depot-form of the drug may solve this compliance problem. There are placebo-controlled studies in the literature which prove the efficacy of this procedure. An additional “psychological deterrent” effect can be mentioned with this method. Its most important difficulty is requirement of a surgical approach. Furthermore, high rates of surgical wound infection and rejection of implants have been reported. There was poor treatment compliance of this patient by reason of second axis pathology of cluster B. Implantation is prefered as the route of administration as the drug cannot be used under supervision because of the deficiency of the patient’s social support system. The aim of this article is to discuss the practice and possible complications of disulfiram implantation in the patient with a diagnosis of alcohol dependency and borderline personality disorder. (Archives of Neuropsychiatry 2008; 45: 103-6)
Resonant Excitation of Terahertz Surface Plasmons in Subwavelength Metal Holes
Weili Zhang,Abul K. Azad,Jiaguang Han
Active and Passive Electronic Components , 2007, DOI: 10.1155/2007/40249
Abstract: We present a review of experimental studies of resonant excitation of terahertz surface plasmons in two-dimensional arrays of subwavelength metal holes. Resonant transmission efficiency higher than unity was recently achieved when normalized to the area occupied by the holes. The effects of hole shape, hole dimensions, dielectric function of metals, polarization dependence, and array film thickness on resonant terahertz transmission in metal arrays were investigated by the state-of-the-art terahertz time-domain spectroscopy. In particular, extraordinary terahertz transmission was demonstrated in arrays of subwavelength holes made even from Pb, a generally poor metal, and having thickness of only one-third of skin depth. Terahertz surface plasmons have potential applications in terahertz imaging, biosensing, interconnects, and development of integrated plasmonic components for terahertz generation and detection.
The Effect of Learning on the Function of Monkey Extrastriate Visual Cortex
Gregor Rainer,Han Lee,Nikos K. Logothetis
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0020044
Abstract: One of the most remarkable capabilities of the adult brain is its ability to learn and continuously adapt to an ever-changing environment. While many studies have documented how learning improves the perception and identification of visual stimuli, relatively little is known about how it modifies the underlying neural mechanisms. We trained monkeys to identify natural images that were degraded by interpolation with visual noise. We found that learning led to an improvement in monkeys' ability to identify these indeterminate visual stimuli. We link this behavioral improvement to a learning-dependent increase in the amount of information communicated by V4 neurons. This increase was mediated by a specific enhancement in neural activity. Our results reveal a mechanism by which learning increases the amount of information that V4 neurons are able to extract from the visual environment. This suggests that V4 plays a key role in resolving indeterminate visual inputs by coordinated interaction between bottom-up and top-down processing streams.
Influence of Magnesite Industry on Imission Load by Solids in the Area of Jel ava
Jozef Han?ulák,Milan Bobro
Acta Montanistica Slovaca , 2004,
Abstract: The contribution deals with the assessment of current imission load by magnesium solids in the area with long-term operation of magnesite industry. The imission load being observed by means of the dust fallout analysis has a decreasing trend. The allowable dust imission limits are exceeded only in the closest vicinity of the processing plant. The content of Mg-component in the dust fallout with the increasing distance from the plant diminishes more dramatically than total dust fallout. As to heavy metals, the area of Jel ava is mostly loaded by manganese. This fact is caused by its occurrence in processed magnesite. The contents of other observed heavy metals are also above an average. A decreasing input of alkalising components of solid immissions into the soil horizon enables to expext a reduction of the contaminated soil area by the reclamation.
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