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Frontiers in Energy 2020年第3期14卷 578-589页

作者： Hilal CELIK KAZICI sakir yilmaz Tekin SAHAN Fikret YILDIZ Omer Faruk ER Hilal KIVRAK Department of Chemical Engineering Faculty of EngineeringVan Yiizuncii Yil University65080 VanTurkey

In this paper,the optimization of hydrogen(H2)production by ammonia borane(NH3BH3)over PdCoAg/AC was investigated using the response surface ***,the electro-oxidation of NH3BH3 was determined and optimized using the same method to measure its potential use in the direct ammonium boran fuel ***,the ternary alloyed catalyst was synthesized using the chemical reduction *** synergistic effect between Pd,Co and Ag plays an important role in enhancement of NH3BH3 *** addition,the support effect could also efficiently improve the catalytic ***,the effects of NH3BH3 concentration(0.1-50 mmol/5 mL),catalyst amount(1-30 mg)and temperature(20℃-50℃)on the rate of H2 production and the effects of temperature(20℃-50℃),NH3BH3 concentration(0.05-1 mol/L)and catalyst amount(0.5-5 jiL)on the electro-oxidation reaction of NH3BH3 were investigated using the central composite design experimental *** implementation of the response surface methodology resulted in the formulation of four models out of which the quadratic model was adjudged to efficiently appropriate the experimental data.A further statistical analysis of the quadratic model demonstrated the significance of the model with a pvalue far less than 0.05 for each model and coefficient of determination(R2)of 0.85 and 0.95 for H2 production rate and NH3BH3 electrroxidation peak current,respectively.

关键词： ammonia borane hydrogen production fuel cell response surface methodology

Computational and Empirical Investigation of Propeller Tip Vortex Cavitation Noise

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China Ocean Engineering 2020年第2期34卷 232-244页

作者： Savas SEZEN sakir BAL aDepartment of Naval Architecture and Marine Engineering Yildiz Technical UniversityIstanbul 34349Turkey bDepartment of Naval Architecture and Marine Engineering Istanbul Technical UniversityIstanbul 34469Turkey

In this study,non-cavitating and cavitating flow around the benchmark DTMB 4119 model propeller are solved using both viscous and potential based *** and non-cavitating propeller radiated noises are then predicted by using a hybrid method in which RANS(Reynolds-averaged Navier-Stokes)and FWH(Ffowcs Williams Hawkings)equations are solved together in open water *** cavitation on the propeller blades is modelled by using a VOF(Volume of Fiuld)method equipped with Schnerr-Sauer cavitation ***,tip vortex cavitation noise is estimated by using two different semi-empirical techniques,namely Tip Vortex Index(TVI,based on potential flow theory)and Tip Vortex Contribution(TVC).As the reference distance between noise source and receiver is not defined in open water case for TVI technique,one of the outputs of this study is to propose a reference distance for TVI technique by coupling two semi-empirical techniques and ITTC distance *** the defined distance,the starting point of the tip vortex cavitation is determined for different advance ratios and cavitation numbers using potential flow ***,it is examined that whether the hybrid method and potential flow solver give the same noise results at the inception point of tip vortex *** show that TVI method based on potential flow theory is reliable and can practically be used to replace the hybrid method(RANS with FWH approach)when tip vortex cavitation starts.

关键词： FWH equation propeller noise tip vortex cavitation TVI TVC

LSTM RNN:detecting exploit kits using redirection chain sequences

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Cybersecurity 2021年第1期4卷 386-400页

作者： Jonah Burgess Philip O’Kane sakir Sezer Domhnall Carlin Centre for Secure Information Technologies(CSIT) Queen’s University BelfastNorthern Ireland Science ParkQueen’s RoadBelfast BT39DTUK

While consumers use the web to perform routine activities,they are under the constant threat of attack from malicious *** when visiting‘trusted’sites,there is always a risk that site is compromised,and,hosting a malicious *** this scenario,the injected script would typically force the victim’s browser to undergo a series of redirects before reaching an attacker-controlled domain,which,delivers the actual *** these malicious redirection chains aim to frustrate detection and analysis efforts,they could be used to help identify web-based *** upon previous work,this paper presents the first known application of a Long Short-Term Memory(LSTM)network to detect Exploit Kit(EK)traffic,utilising the structure of HTTP *** are processed as sequences,where each timestep represents a redirect and contains a unique combination of 48 *** experiment is conducted using a ground-truth dataset of 1279 EK and 5910 benign redirection ***-parameters are tuned via K-fold cross-validation(5f-CV),with the optimal configuration achieving an F1 score of 0.9878 against the unseen test ***,we compare the results of isolated feature categories to assess their importance.

关键词： Exploit kits Malware LSTM

Upper crustal Poisson's ratio and coda-wave attenuation beneath Eastern Anatolia

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Earthquake Engineering and Engineering Vibration 2020年第2期19卷 335-347页

作者： Ufuk Aydin sakir Sahin Mohamed K.Salah Atatürk University Oltu Faculty of Earth SciencesMining EngineeringErzurumTurkey Geophysical Engineering Department SDUEngineering and Architecture FacultyIspartaTurkey Department of Geology American University of BeirutRiad El Solh 11072020BeirutLebanon

The attenuation of seismic waves reflects the elastic nature of the media within which the waves *** this study,we calculate the Coda-Q(Qc),frequency dependence(η),Vp/Vs and Poisson's(υ)ratios by using 2621 vertical component seismograms generated by 987 earthquakes recorded by 13 seismic stations in Eastern Anatolia,and creat a 2-D seismic tomographic Qc model for the *** obtained model provides significant information for exploring the boundaries of adjacent tectonic units within the upper crust and interpreting their dynamic *** 2-D Qc model and the other parameters are consistent with the seismotectonic features of Eastern *** heterogeneous Qc values are observed in the study area dividing it into north-south directed bands of low and high *** highestηvalues were obtained beneath the northwestern and eastern parts of the study ***,high and lowυvalues are obtained in the western and eastern parts of the study area,*** spatial variations in the measured parameters are consistent with many geophysical observations including low Pn velocities,efficient Sn blockage,high heat flow,and widespread *** upper crustal thicknesses and inhomogeneous stress distribution along the East and North Anatolian Fault Zones may also contribute to the observed heterogeneities.

关键词： Coda-Q(Qc) Eastern Anatolia Poisson's ratio(υ) seismotectonics upper crustal structure

Cataract in diabetes mellitus

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World Journal of Diabetes 2019年第3期10卷 140-153页

作者： Hasan Kiziltoprak Kemal Tekin Merve Inanc Yasin sakir Goker Department of Ophthalmology University of Health Sciences Ulucanlar Eye Training and Research Hospital Ankara 06240 Turkey Ophthalmology Department Ercis State Hospital Van 65400 Ercis Turkey

Diabetes mellitus (DM) is a chronic systemic disease that has increases in prevalence over time. DM can affect all ocular structures, with cataract being the most common ocular complication. Cataract is the leading cause of blindness worldwide. Due to several mechanisms, there is an increased incidence of cataract formation in the diabetic population. Advancements in technology have now made cataract surgery a common and safe procedure. However, the diabetic population is still at risk of vision-threatening complications, such as diabetic macular edema (ME), postoperative ME, diabetic retinopathy progression, and posterior capsular opacification.

关键词： Diabetes Cataract Complications Surgery

Use of chorioamniotic membrane instead of bogota bag in open abdomen: How I Do It?

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World Journal of Gastroenterology 2008年第5期14卷 815-816页

作者： sakir Tekin Ahmet Tekin Tevfik Küükkartallar Murat akir Adil Kartal Department of General Surgery Selcuk University Meram Medical Faculty Akyoku Konya 42060 Turkey

It is one of the most important problems for general surgeons to decide which operation should be undertaken on patients with intra-abdominal infection, especially those with concomitant abdominal hypertension. Recentlly, closure techniques using prosthetic meshes in order to retain abdominal tension and to control sepsis have become very popular for patients with abdominal sepsis and hypertension. We used chorioamniotic membrane instead of plastic material to cover the open abdomen. We conclude that human chorioamniotic membrane prepared under sterile conditions may be an alternative to conventional plastic bags in daily practice, for preventing serosal erosion and fistulas in patients undergoing open abdominal surgery.

关键词： Intraabdominal sepsis Chorioamniotic membrane Bogota bag

Quantum Chemical Calculations of Warfarin Sodium,Warfarin and Its Metabolites

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Communications in Computational Physics 2008年第6期4卷 161-176页

作者： Emine Deniz(Calısır)Tekin Figen Erkoc Ilkay Yıldız sakir Erkoc Department of Physics Middle East Technical University06531 AnkaraTurkey Department of Biology Education Gazi University06500 AnkaraTurkey Department of Pharmaceutical Chemistry Faculty of PharmacyAnkara University06100 AnkaraTurkey

The structural,vibrational and electronic properties of warfarin sodium,warfarin and its metabolites have been investigated theoretically by performing the molecular mechanics(MM+force field),the semi-empirical self-consistent-field molecular-orbital(AM1),and density functional theory *** geometry of the molecules have been optimized,the vibrational dynamics and the electronic properties of the molecules have been calculated in their ground state in gas phase.

关键词： Warfarin semi-empirical method ab initio calculation density functional method.

Geology and Geochemistry of Recent Sediments from the Mediterranean Sea:Sediment Texture of Northeastern Mediterranean Basin

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Open Journal of Geology 2013年第6期3卷 371-378页

作者： Semal Yemenicioglu sakir Cagan Tunc Institute of Marine Sciences Middle East Technical University(METU)MersinTurkey Geomarine Kara ve Deniz Arastirmalari MersinTurkey

Surface sediment samples collected from the north-eastern Mediterranean were analysed for their geochemical and sedimentological properties. The sediment texture of the studied area represents a wide variety of sediment types (extending from sandy gravel to mud) and is characterized by relatively high mud content with varying silt and clay fractions. Due to the rich presence of biogenic materials, several coarse-grained sediment patches displaying high CaCO3 content occur. The organic carbon content of the sediments mainly reflects the standard Mediterranean production of organic matter. There are some exceptional areas in coastal zones which result from pollution by perennial river discharge.

关键词： Geochemistry Coastal Sediment Grain Size Carbonate Organic Carbon North-Eastern Mediterranean

Myasthenic crisis-induced Takotsubo cardiomyopathy in an elderly man:A case report of an underestimated but deadly combination

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World Journal of Cardiology 2021年第1期13卷 21-27页

作者： Yvonne Kuo Thomas H Ottens Ivo van der Bilt Ruud WM Keunen sakir Akin Intensive Care Unit HagaziekenhuisThe Hague 2545Netherlands Department of Cardiology HagaziekenhuisThe Hague 2545Netherlands Department of Neurology Haga Teaching HospitalThe Hague 2545Netherlands

BACKGROUND Patients with myasthenia gravis(MG)are at a higher risk of developing Takotsubo cardiomyopathy(TTC),particularly during a myasthenic *** crisis-associated TTC occurs predominantly in *** this case report,we present a man with metastasized prostate carcinoma who developed TTC after new-onset *** SUMMARY An 81-year-old man with non-insulin dependent diabetes mellitus and metastasized prostate carcinoma presented with *** primary assessment examination at the emergency department,there was evident blepharoptosis of his right *** electrocardiograms were suggestive of an acute anterior wall myocardial infarction,for which he underwent emergency coronary *** obstructive coronary artery disease was *** the coronary angiography,the patient developed respiratory failure and was admitted to the Intensive Care Unit for non-invasive respiratory *** following day,diagnostic neostigmine test revealed a myasthenic *** echocardiography revealed left ventricular apical ballooning with a typical appearance of *** the potentially reversible character of both MG and TTC,the patient and family requested an end of support in the Intensive Care Unit due to age and chronic malignancy with reduced quality of life in recent months after non-chemo-responding prostate *** patient died soon after treatment *** Elderly men should be carefully evaluated for TTC when new-onset MG is diagnosed.

关键词： Takotsubo cardiomyopathy Broken heart syndrome Stress-induced cardiomyopathy Myasthenic crisis Respiratory failure Case report

Numerical Simulation of the Flow around Two-dimensional Partially Cavitating Hydrofoils

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Journal of Marine Science and Application 2014年第3期13卷 245-254页

作者： Fahri Celik Yasemin Arikan Ozden sakir Bal Department of Naval Architecture and Marine Engineering Yildiz Technical University Istanbul 34349 Turkey Department of Naval Architecture and Marine Engineering Istanbul Technical University Istanbul 34469 Turkey

In the present study, a new approach is applied to the cavity prediction for two-dimensional （2D） hydrofoils by the potential based boundary element method （BEM）. The boundary element method is treated with the source and doublet distributions on the panel surface and cavity surface by usethe of the Dirichlet type boundary conditions. An iterative solution approach is used to determine the cavity shape on partially cavitating hydrofoils. In the case of a specified cavitation number and cavity length, the iterative solution method proceeds by addition or subtraction of a displacement thickness on the cavity surface of the hydrofoil. The appropriate cavity shape is obtained by the dynamic boundary condition of the cavity surface and the kinematic boundary condition of the whole foil surface including the cavity. For a given cavitation number the cavity length of the 2D hydrofoil is determined according to the minimum error criterion among different cavity lengths, which satisfies the dynamic boundary condition on the cavity surface. The NACA 16006, NACA 16012 and NACA 16015 hydrofoil sections are investigated for two angles of attack. The results are compared with other potential based boundary element codes, the PCPAN and a commercial CFD code （FLUENT）. Consequently, it has been shown that the results obtained from the two dimensional approach are consistent with those obtained from the others.

关键词： boundary element method (BEM):sheet cavitation CFD hydrofoil cavity closure model 2D hydrofoils