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Dependence of Nucleon and Pion-Induced Fission Cross Sections on the Level Density Parameter in the Cascade-Exciton Model

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Chinese Physics Letters 2009年第2期26卷 90-93页

作者： Zafar yasin Physics Division PINSTECH P.O. Nilore Islamabad Pakistan

A new method is used to compute the fission cross sections in which a change of the ratio of the level density parameter in fission to neutron emission channels is taken into account with the change of the incident energy of the projectile. It is shown that fission cross sections induced by nucleons and pions depend on the ratio of the level density parameter in the fission and evaporation modes, i,e. af /an, respectively. We are unable to describe well the cross sections for fission without using this new method. The computed values exhibit reasonable agreement with the experimental data found in the literature across a wide range of beam energies.

关键词： sea surface nonliear interaction numerical method

SYNTHESIS,CHARACTERIZATION,THERMAL DEGRADATION AND ELECTROCHEMICAL PROPERTIES OF OLIGO-4-m-TOLYLAZOMETHINEPHENOL

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Chinese Journal of Polymer Science 2006年第6期24卷 647-656页

作者： smet Kaya yasin Bayrakli Department of Chemistry Faculty of Sciences and Artsanakkale Onsekiz Mart UniversityTR-17020 anakkaleTurkey

The oxidative polycondensation reaction conditions of 4-m-tolylazomethinephenol （4-TAMP） in the presence of air O2 and NaOCl as oxidants were studied in an aqueous alkaline medium between 50 and 90℃. The structures of the obtained monomer and oligomer were confirmed by FT-IR, UV-Vis, ^1H- and ^13C-NMR and elemental analysis techniques. The physical characterization was made by TG-DTA, size exclusion chromatography （SEC） and solubility tests. At the optimum reaction conditions, the yield of oligo-4-m-tolylazomethinephenol （O-4-TAMP） was found to be 62.50% （for air O2 oxidant） and 90.0% （for NaOCl oxidant）, respectively. According to the SEC analysis, the number-average molecular weight （Mn）, weight-average molecular weight （Mw） and polydispersity index （PDI） values of O-4-TAMP were found to be 2310, 2610 g tool 1 and 1. 13, respectively, using air O2, and 1390, 1710 g mol^-1 and 1.23, using NaOCl, respectively. According to TG-DTA analyses, O-4-TAMP was more stable than 4-TAMP against thermal decomposition. The weight losses of 4-TAMP and O-4-TAMP were found to be 68% and 58% at 1000℃. Electrical conductivity of the O-4-TAMP was measured, showing that the polymer is a typical semiconductor. Electrochemically, the highest occupied molecular orbital （HOMO）, the lowest unoccupied molecular orbital （LUMO） and electrochemical energy gaps （E＇g） for 4-TAMP are -5.96, -3.22 and 2.74 eV, respectively. The HOMO, LUMO and （E＇g） for O-4-TAMP are -5.78, -3.44 and 2.34 eV, respectively. According to UV-Vis measurements, optical band gaps （Eg） of 4-TAMP and O-4-TAMP were found to be 3.45 and 3. 1 0 eV, respectively.

关键词： Air O2 NaOCl Oligo-4-m-tolylazomethinephenol Oxidative polycondensation Thermal analysis Band gap Conductivity

A comprehensive approach to understanding irreversibility in a turbojet

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Propulsion and Power Research 2018年第2期7卷 129-137页

作者： yasinŞöhret Department of Airframe and Powerplant Maintenance School of Civil AviationSüleyman Demirel UniversityIspartaTR-32700Turkey

Regarding interest in and concerns about high efficiency in recent times,an irreversibility assessment of energy conversion systems is ***,a type of energy conversion system,are widely used to provide thrust for aerial vehicles,such as military aircraft missiles,commercial aircraft and so *** this point of view,the current study aims to introduce a comprehensive irreversibility assessment methodology exemplification for a *** of all,a basic irreversibility assessment methodology is explained with an *** this,a comprehensive assessment is *** this framework,a number of a novel measures are defined by derivations in addition to previously well-known *** measures are beneficial for the decomposition of the irreversibility in a turbojet and its *** the end of the study,the highest endogenous irreversibility is determined to be in the turbine component of the turbojet engine whereas the highest avoidable irreversibility is found to be in the compressor component of the turbojet *** current paper is considered to be of use for researchers and scientists interested in aero-engine performance,thermal engineering and aerospace engineering.

关键词： Advanced exergy analysis Entropy Exergy destruction Gas turbine Irreversibility Thermodynamics

Defining ecologic thermo-environmental index for aero-engines as a novel performance criterion

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Propulsion and Power Research 2021年第4期10卷 374-382页

作者： yasin Söhret Süleyman Demirel University School of Civil AviationDepartment of Airframe and Powerplant MaintenanceIspartaTurkey

Aviation fleet globally grows in consequence of rise in ridership,number,and hour of *** makes the aviation sector one of the major contributors to the global warming *** this reason,environmental and ecologic aspects should be considered at least as much as performance at design step of an aircraft engine,namely *** evaluate thermodynamics,environmental and ecologic aspects of an aero-engine a holistic approach is lack of the existing *** current paper presents the ecologic thermo-environmental index,as a novel measure,for evaluation of an aero-engine performance from a joint perspective of thermodynamics,ecological and environmental *** better understanding of the dependence of ecologic thermo-environmental index on design parameters of the aero-engine a parametric study is also *** rise in pressure ratio has an increasing impact on the ecologic thermo-environmental index whereas increase in the turbine inlet temperature also leads an increasing impact on the ecologic thermo-environmental *** the other hand,the ecologic thermo-environmental index is found to be inversely proportional to the exergy *** the end of the study,the exergy efficiency of the turbojet engine is calculated to be varying from 44.46%to 57.12%.Additionally,the value of the ecologic thermo-environmental index of the turbojet engine ranges between 0.02 and *** author considers the present study to be beneficial to those interested in aerospace,mechanical,and environmental engineering.

关键词： Aircraft Ecologic function Exergy destruction Gas turbine Thermodynamics Turbojet

Phase diagrams in mixed spin-3/2 and spin-2 Ising system with two alternative layers within the effective-field theory

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Chinese Physics B 2011年第6期20卷 112-124页

作者： Bayram Deviren yasin Polat Mustafa Keskin Department of Physics Nevsehir University Institute of Science Erciyes University Department of Physics Erciyes University

The phase diagrams in the mixed spin-3/2 and spin-2 Ising system with two alternative layers on a honeycomb lattice are investigated and discussed by the use of the effective-field theory with correlations. The interaction of the nearest-neighbour spins of each layer is taken to be positive （ferromagnetic interaction） and the interaction of the adjacent spins of the nearest-neighbour layers is considered to be either positive or negative （ferromagnetic or antiferromagnetic interaction）. The temperature dependence of the layer magnetizations of the system is examined to characterize the nature （continuous or discontinuous） of the phase transitions and obtain the phase transition temperatures. The system exhibits both second- and first-order phase transitions besides triple point （TP）, critical end point （E）, multicritical point （A）, isolated critical point （C） and reentrant behaviour depending on the interaction parameters. We have also studied the temperature dependence of the total magnetization to find the compensation points, as well as to determine the type of behaviour, and N-type behaviour in Neel classification nomenclature existing in the system. The phase diagrams are constructed in eight different planes and it is found that the system also presents the compensation phenomena depending on the sign of the bilinear exchange interactions.

关键词： mixed spin-3/2 and spin-2 Ising system effective-field theory compensation phenomena phase diagrams

Drag Optimization of A Planing Vessel Based on the Stability Criteria Limits

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China Ocean Engineering 2019年第3期33卷 365-372页

作者： yasin MASUMI Amir H.NIKSERESHT Department of Mechanical and Aerospace Engineering Shiraz University of Technology

One of the important phases of designing a craft is stability analysis and optimization of the drag force in cruise speed. In this research the longitudinal and lateral stability of a planing hull craft (DTMB 62 model 4667-1) is investigated with some semi-empirical formulae and the effects of some important design parameters are investigated on the limit of stability region. Also on the basis of these empirical formulations and by using a genetic algorithm the drag force is optimized in each constant cruise speed with the stability criteria limits at a constant beam or projected area. Aspect ratio, the longitudinal position of the gravity center and deadrise angle are the optimization parameters. The results show that the aspect ratio and the longitudinal position of the gravity center are two important parameters in optimizing the drag force and for this planing vessel the drag force can be reduced by 22%.

关键词： longitudinal stability transverse stability drag-optimization Savitsky formula

Comparison of Fission Induced by Protons and Pions

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Chinese Physics Letters 2011年第8期28卷 58-60页

作者： Zafar yasin M.Ikram Shahzad Physics Division PINSTECHP.O.NiloreIslamabadPakistan

We compare the properties of fission induced by protons and *** different methodologies are used to make this ***,it is shown that pion-induced fission cross sections are not much different in magnitude from proton-induced fission cross sections at the same beam kinetic ***,across the pion-nucleon(3,3)resonance so prominent with free nucleons,it has been observed that there is no significant change in the reaction mechanism in the case of ***,it is noted that an empirical expression used for evaluations of proton-induced fission cross sections is also valid for positive pion-induced fission cross sections,at least for actinide *** cross sections computed using a cascade-exciton model code for ^(209)Bi and ^(238)U are also compared with the experimental data available.

关键词： energy beam kinetic

A Model for Cross-Domain Opinion Target Extraction in Sentiment Analysis

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Computer Systems Science & Engineering 2022年第9期42卷 1215-1239页

作者： Muhammet yasin PAK Serkan GUNAL Department of Computer Engineering Eskisehir Technical UniversityEskisehirTurkiye

Opinion target extraction is one of the core tasks in sentiment analysison text data. In recent years, dependency parser–based approaches have beencommonly studied for opinion target extraction. However, dependency parsersare limited by language and grammatical constraints. Therefore, in this work, asequential pattern-based rule mining model, which does not have such constraints,is proposed for cross-domain opinion target extraction from product reviews inunknown domains. Thus, knowing the domain of reviews while extracting opinion targets becomes no longer a requirement. The proposed model also revealsthe difference between the concepts of opinion target and aspect, which are commonly confused in the literature. The model consists of two stages. In the firststage, the aspects of reviews are extracted from the target domain using the rulesautomatically generated from source domains. The aspects are also transferredfrom the source domains to a target domain. Moreover, aspect pruning is appliedto further improve the performance of aspect extraction. In the second stage, theopinion target is extracted among the aspects extracted at the former stage usingthe rules automatically generated for opinion target extraction. The proposedmodel was evaluated on several benchmark datasets in different domains andcompared against the literature. The experimental results revealed that the opiniontargets of the reviews in unknown domains can be extracted with higher accuracythan those of the previous works.

关键词： Opinion target extraction aspect extraction sentiment analysis

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Frontiers of Computer Science 2017年第2期11卷 307-319页

作者： Chuitian RONG yasin N. SILVA Chunqing LI School of Computer Science & Software Engineering Tianjin Polytechnic University Tianjin 300387 China School of Mathematical & Natural Sciences Arizona State University Tempe AZ 85281 USA

String similarity join is an essential operation of many applications that need to find all similar string pairs from two given collections. A quantitative way to determine whether two strings are similar is to compute their similarity based on a certain similarity function. The string pairs with similarity above a certain threshold are regarded as results. The current approach to solving the similarity join problem is to use a unique threshold value. There are, however, several scenarios that require the support of multiple thresholds, for instance, when the dataset includes strings of various lengths. In this scenario, longer string pairs typically tolerate much more typos than shorter ones. Therefore, we proposed a so- lution for string similarity joins that supports different simi- larity thresholds in a single operator. In order to support dif- ferent thresholds, we devised two novel indexing techniques： partition based indexing and similarity aware indexing. To utilize the new indices and improve the join performance, we proposed new filtering methods and index probing tech- niques. To the best of our knowledge, this is the first work that addresses this problem. Experimental results on real-world datasets show that our solution performs efficiently while pro- viding a more flexible threshold specification.

关键词： similarity join similarity aware index similarity thresholds