检索结果-南通市图书馆

The relationship between ischemic stroke and weather conditions in Duzce, Turkey

在线全文

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2015年第3期6卷 207-211页

作者： Harun Gunes Hayati Kandis Ayhan Saritas Suber Dikici ramazan buyukkaya Department of Emergency Medicine Duzce University School of Medicine Department of Neurology Duzce University School of Medicine Department of Radiology Duzce University School of Medicine

BACKGROUND: Weather conditions are thought to increase the risk of stroke occurrence. But their mechanism has not yet been clarified. We investigated possible relationships between ischemic stroke and weather conditions including atmospheric pressure, temperature, relative humidity, and wind ***: One hundred and twenty-eight patients with ischemic stroke who had been admitted to our hospital between January 1 and December 31, 2010 were enrolled in this study. We investigated the relationship between daily cases and weather conditions the same day or 1, 2, and 3 days before ***: A negative correlation was found between maximum wind speed and daily cases 3 days before stroke. As the relationship between daily cases and changes of weather conditions in consecutive days was evaluated, a negative correlation was found between daily cases and change of atmospheric pressure in the last 24 ***: The maximum wind speed 3 days before stroke and change of atmospheric pressure in the last 24 hours were found to increase the cases of ischemic stroke. We recommend that individuals at risk of ischemic stroke should pay more attention to preventive measures, especially on days with low maximum wind speed, on subsequent 3 days, and on days with low atmospheric pressure in the last 24 hours.

关键词： Weather conditions Ischemic stroke Turkey

Effective Mass SchrSdinger Equation via Point Canonical Transformation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2010年第7期27卷 28-31页

作者： Altug Arda ramazan Sever Department of Physics Education Hacettepe University Ankara 06800 Turkey Department of Physics Middle East Technical University Ankara 06531 Turkey

Exact solutions of the effective radial Schrodinger equation are obtained for some inverse potentials by using the point canonical transformation. The energy eigenvalues and the corresponding wave functions are calcul... 详细信息

关键词： Uses Transformation

Micellar sensitized catalytic kinetic spectrophotometry for highly accurate and reproducible determination of Ⅴ(Ⅳ) and Ⅴ(Ⅴ)

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2014年第4期33卷 466-478页

作者： ramazan Grkan Can Emektas Department of Chemistry Faculty of SciencesUniversity of Cumhuriyet

A highly accurate and reproducible micellar sensitized kinetic method was proposed for determination of V（VI）. The method is based on its catalytic effect on the oxidation of Coomassie brilliant blue R 250 （CBB＋） by bromate at pH 2.0. The reaction was monitored spectro- photometrically by measuring absorbance change with a fixed-time method of 5 min at 594 and 552 nm with and without surfactant. The variables influencing the calibra- tion sensitivity were extensively investigated, and the optimal conditions were established. The linear calibration range was 10-1,600 μg.L-1 with a relative SD ranging from 0.35 % to 3.35 % （for five replicate measurements of 75, 500, 1,000, and 1,500 μg.L-1） and a detection limit of 3.8 μg.L-1. The selectivity was also investigated, and greatly enhanced by suitable masking agents. The method was successfully applied to the analysis of V（IV） in pre- sence of excess V（V） up to 25 fold in environmental waters with the recoveries of 100.0 %-102.8 % for V（IV） and 95.7 %-99.7 % for total V. Its accuracy was validated by analysis of certified reference material via the present kinetic method and standard flame atomic absorption spectrometric method after extractive preconcentration with good agreement between certified and found values.

关键词： Vanadium speciation Kineticspectrophotometry Bromate Coomassie brilliant blue R250 Micellar effect

Exact Solutions of Effective Mass Dirac Equation with Non-PT-Symmetric and Non-Hermitian Exponential-type Potentials

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2009年第9期26卷 25-28页

作者： Altug Ardat ramazan Sever Department of Physics Education Hacettepe University 06800 Ankara Turkey Department of Physics Middle East Technical University 06800 Ankara Turkey

By using a two-component approach to the one-dimensional effective mass Dirac equation, bound states are investigated under the effect of two new non-PT-symmetric and non-Hermitian exponential type potentials. It is observed that the Dirac equation can be mapped into a Schrodinger-like equation by rescaling one of the two Dirac wave functions in the case of the position-dependent mass. The energy levels and the corresponding Dirae eigenfunctions are found analytically.

关键词： sea surface nonliear interaction numerical method

Stem taper equations for diameter and volume predictions of Abies cilicica *** the Taurus Mountains,Turkey

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2020年第12期17卷 3054-3069页

作者： Onur ALKAN ramazan OZCELIK Faculty of Forestry Isparta University of Applied SciencesEast Campus32260IspartaTurkey

Taper equations are an important tool in estimating stem volumes at a multi-product level for sustainable forest *** taper equations are tested from three categories to estimate diameter at specified point on the stem,height at specified diameter,volumes of any desired portion of the stem,and whole tree volume of Taurus fir in Taurus Mountains of *** account for autocorrelation and multicollinearity present among multiple stem data observations collected from the same *** statistical approaches were used in model *** are made to determine which equation provides the best overall fit to all data based on four goodness-of-fit statistics,Coefficient of determination(R2);Root mean square error(RMSE),Akaike’s Information Criterion(AIC),and Bayesian information criterion(BIC).Results indicated that all taper equations tested could be used to accurately estimate section diameter at given height and stem *** et al.’s taper equation provided better results than the others for Taurus fir when an additional stem diameter observation at 5.30 m was *** and variable-form taper models consistently provided better results than the simple taper models except for Max and Burkhart’s *** et al.’s and Kozak’s taper models showed equally good performance to describe stem taper and to predict tree stem ***,these taper equations are able to be used to estimate diameter and volume for Taurus fir trees,if an upper stem diameter measurement was not available.

关键词： Autocorrelation Ranking system Stem form Segmented models Variable-form models

Approximate solution to the time-dependent Kratzer plus screened Coulomb potential in the Feinberg–Horodecki equation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第6期29卷 90-97页

作者： Mahmoud Farout ramazan Sever Sameer MIkhdair Department of Physics An-Najah National UniversityNablusPalestine Department of Physics Middle East Technical UniversityAnkara 06531Turkey Department of Electrical Engineering Near East UniversityNicosiaNorthern CyprusMersin 10Turkey

We obtain the quantized momentum eigenvalues Pn together with space-like coherent eigenstates for the space-like counterpart of the Schr¨odinger equation,the Feinberg–Horodecki equation,with a combined Kratzer potential plus screened coulomb potential which is constructed by temporal counterpart of the spatial form of these *** present work is illustrated with two special cases of the general form:the time-dependent modified Kratzer potential and the time-dependent screened Coulomb potential.

关键词： quantized momentum states Feinberg-Horodecki equation the time-dependent screened Coulomb potential and time-dependent modified Kratzer potential

Machine Learning and Classical Forecasting Methods Based Decision Support Systems for COVID-19

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2020年第9期64卷 1383-1399页

作者： ramazanÜnlü Ersin Namlı Gumushane University BağlarbaşıMahGümüşhane29000Turkey Istanbul University-Cerrahpasa İstanbulÜniversitesi Avcılar Kampüsüİstanbul34320Turkey

From late 2019 to the present day,the coronavirus outbreak tragically affected the whole world and killed tens of thousands of *** countries have taken very stringent measures to alleviate the effects of the coronavirus disease 2019(COVID-19)and are still being *** this study,various machine learning techniques are implemented to predict possible confirmed cases and mortality numbers for the *** to these models,we have tried to shed light on the future in terms of possible measures to be taken or updating the current *** Vector Machines(SVM),Holt-Winters,Prophet,and Long-Short Term Memory(LSTM)forecasting models are applied to the novel COVID-19 *** to the results,the Prophet model gives the lowest Root Mean Squared Error(RMSE)score compared to the other three ***,according to this model,a projection for the future COVID-19 predictions of Turkey has been drawn and aimed to shape the current measures against the coronavirus.

关键词： Covid-19 machine learning time series forecasting

Catalytic-kinetic spectrophotometric determination of vanadium (V) based on the Celestine blue-bromate-vanadium (V)-citric acid reaction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2011年第4期30卷 348-358页

作者： ramazan Gürkan Olcay Gürkan Department of Chemistry Faculty of Sciences University of Cumhuriyet Sivas Fen Lisesi Emek mah. 64. Basari Sok. TR-58010 Merkez Sivas TURKEY

A novel sensitive and relatively selective kinetic method is presented for the determination of V（V） based on its catalytic effect on the oxidation reaction of Celestine blue by potassium bromate in the presence of citric acid as an activator. The reaction was monitored spectropho- tometrically by measuring the decrease in absorbance of Celestine blue at a maximum absorption wavelength of 540 nm between 0.5 and 9 min （the fixed-time method） in an H3PO4 medium at 45℃. The effect of various parameters such as concentrations of H3PO4, citric acid, potassium bromate and Celestine blue, ionic strength, reaction temperature and time on the rate of V（V） catalyzed reaction was studied. The method is free from the most interferences, especially from large amounts of V（IV）. The decrease in absorbance is proportional to the concentration of V（V） over the entire concentration range tested （0.025-1.25 ***^-1） with a detection limit of 6.80 tag.L^-1 （according to statistical 3Sblank/k criterion） and a coefficient of variation （CV） of 1.78% （for ten replicate measurements at 95% confidence level）. The proposed method suffers from a few interferences such as Cr（VI） and Hg（Ⅱ） ions. The method was successfully applied to the determination of V（V） in river water, lake water, tap water, natural drinking water samples and a certified standard reference material such as SRM-1640 with satis- factory results. The vanadium contents of natural water samples were detected by using both linear calibration curve and standard addition curve methods. The recoveries of spiked vanadium （V） into the certified standard water sample were found to be quantitative, and the reproducibility was satisfactory. It was observed that the results of the SRM 1640 were in good agreement with the certified value.

关键词： catalytic effect vanadium spectrophotometry bromates Celestine blue citric acid

Approximate Solutions of Dirac Equation with Hyperbolic-Type Potential

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2015年第9期64卷 269-273页

作者： Altug Arda ramazan Sever Department of Physics Education Hacettepe University Department of Physics Middle East Technical University

The energy eigenvalues of a Dirac particle for the hyperbolic-type potential field have been computed approximately. It is obtained a transcendental function of energy, F(E), by writing in terms of confluent Heun *** numerical values of energy are then obtained by fixing the zeros on "E-axis" for both complex functions Re[F(E)]and Im[F(E)].

关键词： hyperbolic-type potential Dirac equation approxima