Annals of West University of Timisoara Physics最新文献_第7页

Electric Properties of NaTaO3 Obtained by Hydrothermal Method 水热法制备NaTaO3的电性质

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0206

D. Malaescu, I. Grozescu, P. Sfirloaga, P. Vlăzan, C. Marin

{"title":"Electric Properties of NaTaO3 Obtained by Hydrothermal Method","authors":"D. Malaescu, I. Grozescu, P. Sfirloaga, P. Vlăzan, C. Marin","doi":"10.1515/awutp-2015-0206","DOIUrl":"https://doi.org/10.1515/awutp-2015-0206","url":null,"abstract":"Abstract Two samples of NaTaO3 perovskite materials were prepared by the standard hydrothermal method at the same reaction temperature (600 °C) but with different sintering times: 6 hours for sample S1 and 12 hours for sample S2. Using X-ray diffraction (XRD), it shows that samples S1 and S2 are mixtures of Na-Ta oxides (Ta2O5 and the prevailing phase NaTaO3). The scanning electron microscopy analysis (SEM), shows that the grains are connected each other in agglomerated clusters of size about few hundred nanometers. The frequency (f) dependencies of complex impedance, Z(f) = Z’(f) - i Z’’(f) of the samples, over the frequency range 20 Hz - 2 MHz, at room temperature are presented. The real component Z’ of the complex impedance decreases with increasing frequency and the imaginary component Z’’ has two maximum corresponding to two relaxation processes. The results obtained from the complex impedance spectroscopy, Z’’(Z’) showed the appearance of two semicircles, corresponding to grain and grain boundary mechanism. Experimental results have been fitted with two parallel RC equivalent circuits connected in series and the parameters R and C have been evaluated.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78912424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Numerical Approach for the Solution of Schrödinger Equation With Pseudo-Gaussian Potentials 伪高斯势Schrödinger方程的数值解法

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0201

Theodor-Felix Iacob, M. Lute, F. Iacob

引用次数: 0

Clouds and the Near-Earth Environment: Possible Links 云和近地环境:可能的联系

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0208

S. Condurache-Bota, M. Voiculescu, C. Dragomir

{"title":"Clouds and the Near-Earth Environment: Possible Links","authors":"S. Condurache-Bota, M. Voiculescu, C. Dragomir","doi":"10.1515/awutp-2015-0208","DOIUrl":"https://doi.org/10.1515/awutp-2015-0208","url":null,"abstract":"Abstract Climate variability is a hot topic not only for scientists and policy-makers, but also for each and every one of us. The anthropogenic activities are considered to be responsible for most climate change, however there are large uncertainties about the magnitude of effects of solar variability and other extraterrestrial influences, such as galactic cosmic rays on terrestrial climate. Clouds play an important role due to feedbacks of the radiation budget: variation of cloud cover/composition affects climate, which, in turn, affects cloud cover via atmospheric dynamics and sea temperature variations. Cloud formation and evolution are still under scientific scrutiny, since their microphysics is still not understood. Besides atmospheric dynamics and other internal climatic parameters, extraterrestrial sources of cloud cover variation are considered. One of these is the solar wind, whose effect on cloud cover might be modulated by the global atmospheric electrical circuit. Clouds height and composition, their seasonal variation and latitudinal distribution should be considered when trying to identify possible mechanisms by which solar energy is transferred to clouds. The influence of the solar wind on cloud formation can be assessed also through the ap index - the geomagnetic storm index, which can be readily connected with interplanetary magnetic field, IMF structure. This paper proposes to assess the possible relationship between both cloud cover and solar wind proxies, as the ap index, function of cloud height and composition and also through seasonal studies. The data covers almost three solar cycles (1984-2009). Mechanisms are looked for by investigating observed trends or correlation at local/seasonal scale","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79573399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nonthermal Argon Plasma Generator and Some Potential Applications 非热氩等离子体发生器及其潜在应用

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0205

M. Bunoiu, I. Jugunaru, I. Bica, M. Bălășoiu

引用次数: 2

Radiofrequency Electromagnetic Field Map of Timisoara 蒂米什瓦拉的射频电磁场图

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0209

N. Stefu, I. Sólyom, A. Arama

引用次数: 0

Approximate Solution of Schrödinger Equation with Pseudo-Gaussian Potential Viewed as a Perturbation 伪高斯势视为扰动的Schrödinger方程的近似解

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0202

Theodor-Felix Iacob, M. Lute, F. Iacob

引用次数: 0

Influence of Mechanical Stirring on the Crucible Dissolution Rate and Impurities Distribution in Directional Solidification of Multicrystalline Silicon 机械搅拌对多晶硅定向凝固坩埚溶解速率和杂质分布的影响

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0204

A. Popescu, D. Vizman

引用次数: 0

The Effect of Particle Concentration on the Heating Rate of Ferrofluids for Magnetic Hyperthermia 磁热疗中颗粒浓度对铁磁流体加热速率的影响

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0210

I. Malaescu, C. Marin, M. Bunoiu, P. C. Fannin, N. Stefu, L. Iordaconiu

引用次数: 3

A Solid State Pyranometer 固态高温计

Annals of West University of Timisoara Physics Pub Date : 2015-12-01 DOI: 10.1515/awutp-2015-0207

Anca Laura Dumitrescu, M. Paulescu, A. Ercuta

引用次数: 1

Complex Impedance of Manganese Ferrite Powders Obtained by Two Different Methods 两种方法制备铁氧体锰粉的复阻抗

Annals of West University of Timisoara Physics Pub Date : 2015-01-01 DOI: 10.1515/awutp-2015-0203

I. Malaescu, A. Lungu, C. Marin, P. Vlăzan, P. Sfirloaga

{"title":"Complex Impedance of Manganese Ferrite Powders Obtained by Two Different Methods","authors":"I. Malaescu, A. Lungu, C. Marin, P. Vlăzan, P. Sfirloaga","doi":"10.1515/awutp-2015-0203","DOIUrl":"https://doi.org/10.1515/awutp-2015-0203","url":null,"abstract":"Abstract Two samples of manganese ferrite powder were obtained by the calcination method (sample A) and hydrothermal method (sample B). The crystal structure of the samples has been determined using X-ray diffraction analysis (XRD). The results shown that the sample A has three phases (FeMnO3, Mn2O3 and Fe2O3) and the prevailing phase is FeMnO3 with perovskite structure and the sample B has only a single phase (MnFe2O4). The grain morphology was analyzed by scanning electron microscopy (SEM) and the compositional analysis was done by energy dispersive spectroscopy (EDAX). Measurements of the frequency (f) and temperature (T) dependent complex impedance, Z(f, T) = Z’(f, T) - i Z’’(f, T) of the samples over the frequency range 20 Hz - 2 MHz, at various temperature values from 300C to 1100C are presented. From these measurements, we have shown that the temperature dependence of the relaxation time is of Arhenius type, which suggests that the conduction process is thermally activated. The values obtained for the activation energy Ea, are: 16meV (sample A) and 147.65meV (sample B). Applying complex impedance spectroscopy technique, the obtained results shows the shape of a single semicircle at each temperature over the measurement range, meaning that the electrical process obeys to a single relaxation mechanism. The impedance and related parameters of the electrical equivalent circuit depend on the temperature and the microstructure of samples. The resistive and capacitive properties of the investigated samples are dominated with the conduction and relaxation processes associated with the grain boundaries mechanism..","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88666364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2