1,458 research outputs found

    Značajke građe i optička svojstava otpuštenih tankih slojeva cdin2se4

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    CdIn2Se4 chalcogenides thin films were prepared by thermal evaporation process. The effect of thermal annealing in vacuum on the growth characteristics of the deposited films was studied using X-ray and transmission electron microscopy techniques. It was observed that the as deposited films (300 K) were poorly crystalline. The degree of crystallinity increases with increasing the annealing temperature from 300 to 500 K. The compositional elemental analysis of CdIn2Se4 thin films annealed at 500 K was found to be nearly stoichiometric, however, films annealed in vacuum at 575 K partially dissociated into two binary phases with CdIn2Se4 as the major phase. The effect of the annealing temperature on the dispersion of the refractive index of the deposited films was investigated and analyzed within the single effective-oscillator approach. Changes of the dispersion parameters were also investigated as a function of the annealing temperature. Analysis of the optical absorption data revealed the existence of allowed direct and indirect optical transitions, and both values of energy gaps decrease with increasing annealing temperature.Isparavanjem u vakuumu pripremali smo tanke slojeve halkogenida CdIn2Se4. Proučavali smo učinke toplinskog otpuštanja u vakuumu na strukturne značajke naparenih slojeva primjenom difrakcije X-zračenja i prolazne elektronske mikroskopije. Opaža se da su svježe (na 300 K) napareni slojevi slabo kristalinični. Stupanj kristaliničnosti povećava se s povišenjem temperature otpuštanja između 300 i 500 K. Analize elementalnog sastava tankih slojeva CdIn2Se4 otpuštenih do 500 K pokazale su gotovo točan stoihiometrijski sastav, međutim, slojevi otpušteni na 575 K djelomično se razlažu u dvije binarne faze, dok CdIn2Se4 ostaje glavna faza. Mjerili smo učinke otpuštanja na disperzivnost indeksa loma naparenih slojeva i analizirali ishode jedno-oscilatornim modelom. Promjene parametara disperzije također smo istraživali u ovisnosti o temperaturi otpuštanja. Analize podataka za optičku apsorpciju ukazuju na postojanje dozvoljenih izravnih i neizravnih optičkih prijelaza s padom širina procijepa za povećne temperature otpuštanja

    Značajke građe i optička svojstava otpuštenih tankih slojeva cdin2se4

    Get PDF
    CdIn2Se4 chalcogenides thin films were prepared by thermal evaporation process. The effect of thermal annealing in vacuum on the growth characteristics of the deposited films was studied using X-ray and transmission electron microscopy techniques. It was observed that the as deposited films (300 K) were poorly crystalline. The degree of crystallinity increases with increasing the annealing temperature from 300 to 500 K. The compositional elemental analysis of CdIn2Se4 thin films annealed at 500 K was found to be nearly stoichiometric, however, films annealed in vacuum at 575 K partially dissociated into two binary phases with CdIn2Se4 as the major phase. The effect of the annealing temperature on the dispersion of the refractive index of the deposited films was investigated and analyzed within the single effective-oscillator approach. Changes of the dispersion parameters were also investigated as a function of the annealing temperature. Analysis of the optical absorption data revealed the existence of allowed direct and indirect optical transitions, and both values of energy gaps decrease with increasing annealing temperature.Isparavanjem u vakuumu pripremali smo tanke slojeve halkogenida CdIn2Se4. Proučavali smo učinke toplinskog otpuštanja u vakuumu na strukturne značajke naparenih slojeva primjenom difrakcije X-zračenja i prolazne elektronske mikroskopije. Opaža se da su svježe (na 300 K) napareni slojevi slabo kristalinični. Stupanj kristaliničnosti povećava se s povišenjem temperature otpuštanja između 300 i 500 K. Analize elementalnog sastava tankih slojeva CdIn2Se4 otpuštenih do 500 K pokazale su gotovo točan stoihiometrijski sastav, međutim, slojevi otpušteni na 575 K djelomično se razlažu u dvije binarne faze, dok CdIn2Se4 ostaje glavna faza. Mjerili smo učinke otpuštanja na disperzivnost indeksa loma naparenih slojeva i analizirali ishode jedno-oscilatornim modelom. Promjene parametara disperzije također smo istraživali u ovisnosti o temperaturi otpuštanja. Analize podataka za optičku apsorpciju ukazuju na postojanje dozvoljenih izravnih i neizravnih optičkih prijelaza s padom širina procijepa za povećne temperature otpuštanja

    Adenosine A2A Receptor Blockade Prevents Rotenone-Induced Motor Impairment in a Rat Model of Parkinsonism

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    Pharmacological studies implicate the blockade of adenosine receptorsas an effective strategy for reducing Parkinson’s disease (PD) symptoms. The objective of this study is to elucidate the possible protective effects of ZM241385 and 8-cyclopentyl-1, 3-dipropylxanthine, two selective A2A and A1 receptor antagonists, on a rotenone rat model of PD. Rats were split into four groups: vehicle control (1 ml/kg/48 h), rotenone (1.5 mg/kg/48 h, s.c.), ZM241385 (3.3 mg/kg/day, i.p) and 8-cyclopentyl-1, 3-dipropylxanthine (5 mg/kg/day, i.p). After that, animals were subjected to behavioral (stride length and grid walking) and biochemical (measuring concentration of dopamine levels using high performance liquid chromatography, HPLC). In the rotenone group, rats displayed a reduced motor activity and disturbed movement coordination in the behavioral tests and a decreased dopamine concentration as foundby HPLC. The effect of rotenone was partially prevented in the ZM241385 group, but not with 8-cyclopentyl-1,3-dipropylxanthine administration. The administration of ZM241385 improved motor function and movement coordination (partial increase of stride length and partial decrease in the number of foot slips) and an increase in dopamine concentration in the rotenone-injected rats. However, the 8-cyclopentyl-1,3-dipropylxanthine and rotenone groups were not significantly different. These results indicate that selective A2A receptor blockade by ZM241385, but not A1 receptor blockadeby 8-cyclopentyl-1,3-dipropylxanthine, may treat PD motor symptoms. This reinforces the potential use of A2A receptor antagonists as a treatment strategy for PD patients

    Synthesis of New Formyl Halo N-methylimidazole Derivatives

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    Bromo-formyl imidazoles 16-20 have been prepared by three different ways. The first consisted of conversion of bromo or iodo imidazoles 1-6 into diethyl acetals 13-15, and subsequent hydrolysis into formyl derivatives 7-9. In the second, bromination of. formyl imidazoles with NBS afforded compounds 16-18 in 45-70°/o yield. The third method used direct formylation of bromo imidazoles 10-12 with n-BuLi/DMF reagent into compounds 16, 19, and 20

    Effect of Tempering Temperatures on the Mechanical Properties of Cu-Al Alloy

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    FACTS allocation considering loads uncertainty, steady state operation constraints, and dynamic operation constraints

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    This study proposes an algorithm to allocate different types of flexible AC transmission system (FACTS) in power systems. The main objective of this study is to maximize profit by minimizing the system’s operating cost including FACTS devices (FDs) installation cost. Dynamic and steady state operating restrictions with loads uncertainty are included in the problem formulation. The overall problem is solved using both teaching learning based optimization (TLBO) technique for attaining the optimal allocation of the FDs as main-optimization problem and matpower interior point solver (MIPS) for optimal power flow (OPF) as the sub-optimization problem. The validation of the proposed approach is verified by applying it to test system of 59-bus; Simplified 14-Generator model of the South East Australian power system

    Population based optimization algorithms improvement using the predictive particles

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    A new efficient improvement, called Predictive Particle Modification (PPM), is proposed in this paper. This modification makes the particle look to the near area before moving toward the best solution of the group. This modification can be applied to any population algorithm. The basic philosophy of PPM is explained in detail. To evaluate the performance of PPM, it is applied to Particle Swarm Optimization (PSO) algorithm and Teaching Learning Based Optimization (TLBO) algorithm then tested using 23 standard benchmark functions. The effectiveness of these modifications are compared with the other unmodified population optimization algorithms based on the best solution, average solution, and convergence rate

    Generalized optimal placement of PMUs considering power system observability, communication infrastructure, and quality of service requirements

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    This paper presents a generalized optimal placement of Phasor Measurement Units (PMUs) considering power system observability, reliability, Communication Infrastructure (CI), and latency time associated with this CI. Moreover, the economic study for additional new data transmission paths is considered as well as the availability of predefined locations of some PMUs and the preexisting communication devices (CDs) in some buses. Two cases for the location of the Control Center Base Station (CCBS) are considered; predefined case and free selected case. The PMUs placement and their required communication network topology and channel capacity are co-optimized simultaneously. In this study, two different approaches are applied to optimize the objective function; the first approach is combined from Binary Particle Swarm Optimization-Gravitational Search Algorithm (BPSOGSA) and the Minimum Spanning Tree (MST) algorithm, while the second approach is based only on BPSOGSA. The feasibility of the proposed approaches are examined by applying it to IEEE 14-bus and IEEE 118-bus systems

    The relationship between associative learning, transfer generalization, and homocysteine levels in mild cognitive impairment

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    Previous studies have shown that high total homocysteine levels are associated with Alzheimer's disease (AD) and mild cognitive impairment (MCI). In this study, we test the relationship between cognitive function and total homocysteine levels in healthy subjects (Global Dementia Rating, CDR = 0) and individuals with MCI (CDR = 0.5). We have used a cognitive task that tests learning and generalization of rules, processes that have been previously shown to rely on the integrity of the striatal and hippocampal regions, respectively. We found that total homocysteine levels are higher in MCI individuals than in healthy controls. Unlike what we expected, we found no difference between MCI subjects and healthy controls in learning and generalization. We conducted further analysis after diving MCI subjects in two groups, depending on their Global Deterioration Scale (GDS) scores: individuals with very mild cognitive decline (vMCD, GDS = 2) and mild cognitive decline (MCD, GDS = 3). There was no difference among the two MCI and healthy control groups in learning performance. However, we found that individuals with MCD make more generalization errors than healthy controls and individuals with vMCD. We found no difference in the number of generalization errors between healthy controls and MCI individuals with vMCD. In addition, interestingly, we found that total homocysteine levels correlate positively with generalization errors, but not with learning errors. Our results are in agreement with prior results showing a link between hippocampal function, generalization performance, and total homocysteine levels. Importantly, our study is perhaps among the first to test the relationship between learning (and generalization) of rules and homocysteine levels in healthy controls and individuals with MCI
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