检索结果-南通市图书馆

A Collocation Technique via Pell-Lucas Polynomials to Solve Fractional Differential EquationModel for HIV/AIDS with Treatment Compartment

引用

Computer Modeling in Engineering & Sciences 2024年第10期141卷 281-310页

作者： Gamze Yıldırım Suayip Yüzbası Department of Mathematics Faculty of ScienceAkdeniz UniversityAntalya07058Turkey Department of Mathematics Faculty of Basic ScienceGebze Technical UniversityKocaeli41400Turkey Department of Mathematics Faculty of ScienceBartın UniversityBartın74100Turkey

In this study,a numerical method based on the Pell-Lucas polynomials(PLPs)is developed to solve the fractional order HIV/AIDS epidemic model with a treatment *** HIV/AIDS mathematical model with a treatment compartment is divided into five classes,namely,susceptible patients(S),HIV-positive individuals(I),individuals with full-blown AIDS but not receiving ARV treatment(A),individuals being treated(T),and individuals who have changed their sexual habits sufficiently(R).According to the method,by utilizing the PLPs and the collocation points,we convert the fractional order HIV/AIDS epidemic model with a treatment compartment into a nonlinear system of the algebraic ***,the error analysis is presented for the Pell-Lucas approximation *** aim of this study is to observe the behavior of five populations after 200 days when drug treatment is applied to HIV-infectious and full-blown AIDS *** demonstrate the usefulness of this method,the applications are made on the numerical example with the help of *** addition,four cases of the fractional order derivative(p=1,p=0.95,p=0.9,p=0.85)are examined in the range[0,200].Owing to applications,we figured out that the outcomes have quite decent ***,we understand that the errors decrease when the value of n *** figures in this study are created in *** outcomes indicate that the presented method is reasonably sufficient and correct.

关键词： Collocation method fractional differential equations HIV/AIDS epidemic model Pell-Lucas polynomials

来源：

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

Analysis of the high-temperature dry sliding behavior of CoCrFeniTi0.5Alx high-entropy alloys

引用

Friction 2020年第1期8卷 198-207页

作者： Azmi ERDOGAn Mustafa Sabri GOK Sakin ZEYTIn Department of Metallurgy and Materials Engineering Faculty of EngineeringBartın UniversityBartın 74100Turkey Department of Mechanical Engineering Faculty of EngineeringBartın UniversityBartın 74100Turkey Department of Metallurgy and Materials Engineering Faculty of EngineeringSakarya UniversitySakarya 54100Turkey

In this study,CoCrFeniTi0.5Alx high‐entropy alloys were produced by induction melting and their dry sliding wear behavior was examined at different *** addition to face‐centered cubic(FCC)phases,low amounts of a tetragonal phase were detected in the microstructures of alloys without Al and microscratches were formed by wear particles on the worn surfaces of the alloy *** body‐centered cubic(BCC)phases were detected in the alloy with 0.5Al and a fatigue‐related extrusion wear mechanism was detected on the worn *** alloy specimen with a high Al content exhibited the best wear *** wear tracks were formed in single‐phase BCC intermetallic alloys at room temperature and they exhibited a higher wear strength at high temperatures when compared to other samples.

关键词： high‐entropy alloy dry sliding wear friction intermetallic

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of Applied Current Density on Morphological and Structural Properties of Electrodeposited Fe-Cu Films

引用

Journal of Materials Science & Technology 2012年第11期28卷 1004-1009页

作者： Umut Sarac M.Celalettin Baykul Department of Elementary Education Bart n University Department of Physics Eskisehir Osmangazi University

A detailed study has been carried out to investigate the effect of applied current density on the composition, crystallographic structure, grain size, and surface morphology of Fe-Cu films. X-ray diffraction （XRD） results show that the films consist of a mixture of face-centered cubic （fcc） Cu and body centered cubic （bcc） ^-Fe phases. The average crystalline size of both Fe and Cu particles decreases as the applied current density becomes more negative. Compositional analysis of Fe-Cu films indicates that the Fe content within the films increases with decreasing current density towards more negative values. Scanning electron microscopy （SEM） and atomic force microscopy （AFM） have been used to investigate the surface morphology of Fe-Cu films. It is observed that the surface morphology of the films changes from dendritic structure to a cauliflower structure as the applied current density becomes more negative. The surface roughness and grain size of the Fe-Cu films decrease with decreasing applied current density towards more negative values.

关键词： Electrodeposition Surface morphology Current density Grain size Composition

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Physical,Anatomical,and Photochemical Analyses of Some ExoticWood Species Submitted to Heat Treatment

引用

Journal of Renewable Materials 2021年第8期9卷 1485-1501页

作者： Alper Aytekin Hikmet Yazıcı bartın university Department of Management Information SystemsBartın74100Turkey Zonguldak Bulent Ecevit university Çaycuma Vocational SchoolZonguldak67100Turkey

The objective of this study was to evaluate the effect of heat treatment on decorative properties including glossiness,color coordinates including lightness(L),blue-yellow(b^(*))and red-green(a^(*)),hardness(shore-D)morphological characterization and thermal properties of some exotic wood *** treatment of anigre(Aningeria altissima),cedrorana(Cedrelinga catenaeformis),cemara(Casuarina sumatrana)and coronilla(Scutia buxifolia)wood materials were performed in an oven with a programmable controller at 210°C for 3 *** obtained samples were conditioned in a climate cabin and the decorative properties,morphological characterization with scanning electron microscopy(SEM)and thermal properties with thermogravimetric analyzer(TGA)of the obtained samples were *** test results showed that color got darker with heat treatment,specifically L and b^(*)decreased,and a^(*)increased for anigre and cedrorana but a^(*)decreased for cemara and *** glossiness for all samples generally increased from 20°to 85°but heat treatment decreased the *** density generally decreased with heat treatment and decrease ratio in the density was found to be in range from 5.6%to 10.6%.According to the SEM analysis,some cracks,pit aspiration and layer decomposition in the micro level of the wood structure were *** showed that heat treatment makes thermally more stable *** a result,it can be said that heat treatment improved the decorative properties of the exotic wood.

关键词： Heat treatment color gloss hardness anigre wood cedrorana wood cemara wood coronilla wood

来源：

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

Analysis of the forest fires in the Antalya region of Turkey using the Keetch–Byram drought index

引用

Journal of Forestry Research 2016年第4期27卷 811-819页

作者： Tugrul Varol Mertol Ertugrul Forest Engineering Department Faculty of Forestry Bart?n University

We investigated the correlation of large fires（[300 ha） from 1992 to 2013 within the borders of the Antalya Regional Directorate of Forestry using the Keetch–Byram drought index（KBDI）. Daily KBDI values were calculated for each year, and values for the period before the year 2000 differed significantly from those after2000. After 2000（large fires occurred in 2004, 2006, 2007,2008, 2010, and 2013）, when KBDI values increased, the KBDI, but not the number of fires, was inversely correlated with the natural log of the burned area（nLBA）. While there were both high and low KBDI values when the nLBA was small, only high KBDI values were associated with high nLBA values. Particularly for logarithmic values of 4 and higher, KBDI values increased in parallel with increases in nLBA values. On the basis of a Mann–Whitney U test done in addition to a Pearson correlation test, we found that when the burned areas were grouped according to small and large areas, the KBDI could be used to distinguish the two groups. Using a conditional probability analysis, we found that 4th, 5th and 6th class KBDI values may lead to large fires at the 60 % ***, the possibility of large fires greater than the median burned area in any given 6 years was found to be48 %. In addition, while the mean value of KBDI is 390.51 for the period from May to September for these 6 years, it is 359.93 for the other years. Consequently, the area burned also increased as the KBDI classes（Class 0： 0–99, Class 1：100–199, Class 2： 200–299, Class 3： 300–399, Class 4：400–499, Class 5： 500–599, Class 6： 600–699, and Class 7：700–800） increase.

关键词： drought grouped possibility distinguish median Turkey conditional explained moisture ranged

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of stand types on recreational preferences of society in the Sub-Alpine Zone,northern Turkey

引用

Journal of Mountain Science 2022年第11期19卷 3246-3256页

作者： Tuğrul VAROL Halil BarışÖZEL Ferhat KARA İlkimÇAVUŞKARA Sezgin AYAn bartın university Faculty of ForestryDepartment of Forest EngineeringBartın 74100Turkey Kastamonu university Faculty of ForestryDepartment of Forest EngineeringKastamonu 37150Turkey Kastamonu-Ilgaz Mountain national Park Directorate Kastamonu 37100Turkey

The main objective of this study was to examine how different stand types influenced the tendency of visitors for varying recreational activities(i.e.,hiking,trekking,camping and hunting)from 1993 to 2018 in the surrounding areas of Uluyayla natural Recreation Site in bart1n,northern Turkey.A total of 627 visitors were selected on a voluntary basis,and questioned in the form of *** of the participants were in the age of 21-40 years old,and they were mostly(62.4%)*** of the participants(82.7%)lived in cities,while 62.8%of them were tourists when visiting the *** determining the preferences of the visitors regarding the stand types for different recreational activities,several images of each stand were shared with them,and they were asked which stand type they would prefer for a given recreation activity(i.e.,hiking,tracking,camping and hunting).A range of options from 1 to 5 in Likert's scale was used in evaluating the given *** degree of positive and negative effects was examined via trend *** was found that stand type had influence on the preferences of visitors regarding the recreational *** general,unmanaged and moderately treated stands were more preferred by visitors for the recreational purposes,compared to the previously managed *** the other hand,visitors'preference for the activities were different during two periods(i.e.,1993-2005 and 2006-2018).For each recreational activity,there was an increasing trend from 1993 to *** had been a continuous increase for hunting since 1996,and for trekking and camping after *** increases between 1993-1996 and 1996-1999 were likely due to the increasing awareness of the society as a result of the training and consciousness raising activities for nature *** demand on the recreational activities continuously increased in unmanaged and moderately treated stands,while no significant changes were examined in the previously managed *** st

关键词： Camping Hunting national Park Recreation Subalpine Silviculture

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Diameter distributions in Pinus sylvestris ***:evaluating modelling approaches including a machine learning technique

引用

林业研究:英文版 2023年第6期34卷 1829-1842页

作者： Şükrü Teoman Güner Maria J.Diamantopoulou Ramazan Özçelik Department of Forestry Ulus Vocational SchoolBartın University74600 UlusBartınTurkey Faculty of Agriculture Forestry and Natural EnvironmentSchool of Forestry and Natural EnvironmentAristotle University of Thessaloniki54124 ThessalonikiGreece Faculty of Forestry Isparta University of Applied ScienceEast Campus32260 IspartaTurkey

The diameter distribution of trees in a stand provides the basis for determining the stand’s ecological and economic value,its structure and stability and appropriate management *** pine(Pinus sylvestris L.)is one of the most common and important conifers in Turkey,so a well-planned management schedule is *** distribution models to accurately describe the stand structure help improve management strategies,but developing reliable models requires a deep understanding of the growth,output and constraints of the *** most important information derived by diameter distribution models is primary data on horizontal stand structure for each diameter class of trees:basal area and volume per unit *** predictions are required to estimate the range of products and predicted volume and yield from a forest ***,to construct an accurate,reliable diameter distribution model for natural Scots pine stands in the Türkmen Mountain region,we used Johnson’s SBdistribution to represent the empirical diameter distributions of the stands using ground-based measurements from 55 sample plots that included1219 trees in natural distribution zones of the *** an alternative,nonparametric approach,which does not require any predefined function,an artificial intelligence model was constructed based on support vector machine *** error index was calculated to evaluate the ***,both Johnson’s SB probability density function with a three-parameter recovery approach and the support vector regression methodology provided reliable estimates of the diameter distribution of these stands.

关键词： Diameter distribution Johnson’s S_(B) Support vector regression Scots pine Türkmen mountains

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Influence of Sn addition on microstructure and corrosion resistance of AS21 magnesium alloy

引用

Transactions of nonferrous Metals Society of China 2019年第7期29卷 1413-1423页

作者： Huseyin ZEnGIn Yunus TUREn Hayrettin AHLATCI Yavuz SUn Abdullah Cahit KARAOGLAnLI Department of Metallurgical and Materials Engineering Karabuk University Turkey Department of Metallurgical and Materials Engineering Bartιn University Turkey

This study aims to investigate the influence of Sn addition on microstructure and corrosion properties of AS21 magnesium alloys. The AS21 alloys with 0, 0.5, 1 and 2 wt.% Sn additions were produced by low pressure die casting method. Microstructure characterizations were performed by optical and scanning electron microscopy. Corrosion properties of the alloys were examined by immersion and electrochemical corrosion tests in 3.5% naCl solution. The microscopic results showed that AS21 alloy consisted of α-Mg, isolated β-Mg17Al12 and Chinese script type Mg2Si intermetallic phases. With increasing amount of Sn, the distribution of Mg2Si phase became more discrete and denser. After 2 wt.% Sn addition, a Sn-rich network structure formed throughout the microstructure and islands of Chinese script shape were made of shorter rods of Mg2Si phase. The constant immersion corrosion tests revealed that increasing Sn addition led to a continual decrease in the degradation of AS21 alloys, in which the corrosion rate of AS21 alloy was decreased by approximately 65% with 2 wt.% Sn addition. The electrochemical corrosion tests also showed that the corrosion resistance of AS21 alloy was gradually improved with increasing Sn content.

关键词： AS21 magnesium alloy Sn addition microstructure corrosion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Epidemiology of hepatitis B virus in Bangladeshi general population

引用

Hepatobiliary & Pancreatic Diseases International 2008年第6期7卷 595-600页

作者： Mamun-Al Mahtab Salimur Rahman Md.Fazal Karim Mobin Khan Graham Foster Susannah Solaiman Shahrin Afroz Department of Hepatology Bangabandhu Sheikh Mujib Medical university Digestive Diseases Research Centre Bart's and the London Queen Mary's School of Medicine and Dentistry Department of Gastroenterology Bangabandhu Sheikh Mujib Medical university

BACKGROUnD:Hepatitis B virus(HBV)is encountered sporadically the year round in *** results in a wide range of liver diseases,with asymptomatic acute hepatitis at one end to hepatocellular carcinoma(HCC)at the other end of the spectrum. METHODS:All 1018 individuals of different age groups and sex with varied religious,educational and social backgrounds were tested for HBsAg by *** positive samples were further tested by ELISA for *** testing,blood samples were preserved at-20℃.The study was conducted in a semi-urban location on the outskirts of Dhaka. RESULTS:Of the 1018 individuals,5.5%tested positive for *** were tested positive for *** the HBsAg-positive population,58.93%were HBeAg- positive and the rest 41.07%*** was a male predominance and those who were tested positive were mostly between 16 and 50 years of *** risk factors for exposure to HBV appeared to be injudicious use of injectable medications,treatment by unqualified, traditional practitioners,mass-vaccination against cholera and smallpox,barbers and body piercing. COnCLUSIOn:HBV remains a major cause of morbidity and mortality in Bangladesh and we have a long way to go before we may bid farewell to this deadly menace.

关键词： hepatitis B virus prevalence general population Banglandesh

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Tree species identity and interaction determine vertical forest structure in young planted forests measured by terrestrial laser scanning

引用

Forest Ecosystems 2024年第3期11卷 266-275页

作者： Mengxi Wang Lander Baeten Frieke Van Coillie Kim Calders Kris Verheyen Quentin Ponette Haben Blondeel bart Muys John Armston Hans Verbeeck Q-ForestLab Department of EnvironmentFaculty of Bioscience EngineeringGhent UniversityBelgium Forest&nature Lab Department of EnvironmentFaculty of Bioscience EngineeringGhent UniversityBelgium Earth and Life Institute Université Catholique de Louvain(UCLouvain)Louvain-la-NeuveBelgium Department of Earth&Environmental Sciences KU LeuvenBelgium Department of Geographical Sciences University of MarylandCollege ParkMDUSA

Vertical forest structure is closely linked to multiple ecosystem characteristics,such as biodiversity,habitat,and *** tree species in planted forests has the potential to create diverse vertical forest structures due to the different physiological and morphological traits of the composing tree ***,the relative importance of species richness,species identity and species interactions for the variation in vertical forest structure remains unclear,mainly because traditional forest inventories do not observe vertical stand structure in *** laser scanning(TLS),however,allows to study vertical forest structure in an unprecedented ***,we used TLS single scan data from 126 plots across three experimental planted forests of a largescale tree diversity experiment in Belgium to study the drivers of vertical forest *** plots were 9–11years old young pure and mixed forests,characterized by four levels of tree species richness ranging from monocultures to four-species mixtures,across twenty composition *** generated vertical plant profiles from the TLS data and derived six stand structural *** mixed models were used to test the effect of species richness on structural *** a hierarchical diversity interaction modelling framework,we further assessed species identity effect and various species interaction effects on the six stand structural *** results showed that species richness did not significantly influence most of the stand structure variables,except for canopy height and foliage height *** identity on the other hand exhibited a significant impact on vertical forest structure across all *** interaction effects were observed to be site-dependent due to varying site conditions and species pools,and rapidly growing tree species tend to dominate these ***,our results highlighted the importance of considering both species identity an

关键词： TreeDivnet FORBIO Stand structural complexity Terrestrial laser scanning Vertical forest structure Tree diversity Planted forests

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：