检索结果-南通市图书馆

作者： mahmoud mohammed ahmed hamdy hassanien 扬州大学

学位级别：硕士

1.绪论1.1背景和意义研究干旱变化对区域生态环境保护和可持续发展具有重要意义。根据世界气象组织(WMO)的统计,全球气象灾害约占所有自然灾害的70%,而干旱占所有气象灾害的比例达50%。干旱带来的损失也是自然灾害中最大的。近几十年来... 详细信息

1.绪论1.1背景和意义研究干旱变化对区域生态环境保护和可持续发展具有重要意义。根据世界气象组织(WMO)的统计,全球气象灾害约占所有自然灾害的70%,而干旱占所有气象灾害的比例达50%。干旱带来的损失也是自然灾害中最大的。近几十年来,全球干旱情况变得更加严重,影响也更为广泛。干旱也是我国农业面临的主要挑战性自然灾害之一,位于黑龙江省西部半干旱区的松嫩平原是我国重要的商品粮基地。该区处于我国东北高纬度寒区,半干旱季风气候显著,年降水量时空分布不均,冬季积雪少,春季干旱频发,气象条件对农业生产非常不利。开展该地区干旱变化特性与评估的研究,可为该地区防治和减轻干旱的影响,科学评价气候演变特征以及实现水资源的科学管理提供基础数据。对保障黑龙江省西部粮食产能和农业的可持续发展以及实现生态安全具有重要意义。1.2研究内容和技术路线1.2.1主要研究内容(1)黑龙江省西部半干旱区干旱特性评估选取具有黑龙江省西部半干旱气候特性的典型研究区,采用不同的单位时间间隔(1、3、6、12、24个月),推求研究区各时间间隔的标准化降水指数(Standardized Precipitation Index,SPI)和标准化降水-蒸散指数(Standardized Precipitation Evapotranspiration Index,SPEI),通过对不同时间间隔SPI和SPEI结果的分析,评价研究区各时间尺度的气象干旱特征及趋势。(2)主要气象因子的时间变异性分析采用变异系数法,计算研究区研究时段内各主要气象因子如降水量、气温、湿度、日照时数等年平均值序列的变异系数,通过对各气象因子变异系数的分析,对研究区各因子的变异性进行评价。(3)主要气象因子对降水的影响程度分析以年降水量为因变量,气温、相对湿度、日照时数和风速为自变量,构建多元线性回归模型,评价各因子对年降水量的线性相关程度以及影响的大小。(4)SPI和SPEI相关性分析针对不同的时间尺度(1、3、6、12和24个月)建立线性回归模型,以SPEI为因变量,SPI为自变量构建线性预测模型,验证各时间尺度SPEI和SPI值之间的差异性以及评价SPI和SPEI之间的线性关系。1.2.2技术路线根据研究的主要内容、所采用的研究方法和手段,拟采用的技术路线图如图1所示。2.材料和方法2.1研究区简介研究区位于黑龙江省西部(46°14’24"22°2624"25°31’48"E)(见图2),该区主要位于齐齐哈尔地区境内,处于松嫩平原腹地,冬季漫长寒冷,夏季短暂凉爽,年均气温2.0.5°C;多年平均降雨量450mm左右,降雨季节性分布不均,超过80%集中在6月的雨季;年潜在蒸散发量超过1000 mm,年降雨蒸发比在0.2.5之间,为半干旱区。研究区位置如图2所示。2.2气象数据收集在国家气象科学数据中心获取了研究区1961015年6个气象站的逐日气象数据(降水量、温度、相对湿度、太阳辐射和风速),气象站的分布如图2所示。2.3研究方法2.3.1 SPI和SPEI SPI是由美国科学家McKee等于1993年提出的一种多时间尺度干旱指数,采用Gamma函数来描述降水量的变化,只需降水量即可计算,通过SPI值可判别所评价的时间尺度内是否发生了干旱及其对应的等级,计算过程见文献。1月尺度SPI(SPI1)和3月尺度SPI(SPI3)能够反映短期气象旱涝特征,与农业干旱关系密切;6月尺度SPI(SPI6)和12月尺度SPI(SPI12)可以清楚地反映长期的旱涝变化特征,其中,SPI2对长期旱涝影响及持续时段具有显著的标识功能,通常与河流水位,水库水位,甚至地下水位相关度较高,因此,多种时间尺度的SPI综合应用可实现对旱涝的综合监测评估。SPEI的计算是基于月降水与同期潜在蒸散量的差值D=P-PET(D为月降水量与潜在蒸散量的差值;P为月降水量,为月潜在蒸散发量,单位均为mm),采用Log-logistic分布函数对A数据序列求累积概率,进行正态化,最终可得到不同时间尺度如1、3、6、9、12、24月等的SPEI值,计算过程可参考文献。McKee等(1993)基于SPI值对干旱进行了分级。在某些同类研究中,对Mackee(1993)基于SPI值的干旱分级标准进行了拓展,并包含了湿润分级,也有研究采用SPEI值对干旱(含湿润)进行分级,丰富和发展了干旱分级方法。本文在参考同类研究对干旱(含湿润)分级方法的基础上,采用不同SPI和SPEI值对干旱等级进行划分(见表1)。PET的计算方法有很多种,FAO-56推荐的彭曼-蒙蒂斯(P-M)公式(式1)综合考虑了温度、太阳辐射量、风速和相对湿度对蒸散发的影响,因此,本文采用P-M公式推求尸五r。(?)式中:为潜在蒸散发量,rrmrd;A为不同温度下饱和水汽压曲线上的斜率,

关键词：黒龙江省西部半干旱区气候变化标准化降水指数标准化降水-蒸散指数多元线性回归分析

来源：

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Kaoline-based catalyst for a high stability desulfurization of sour heavy naphtha in a three-phase oscillatory baffled reactor

引用

Particuology 2024年第1期84卷 249-260页

作者： Hassan M.Hmood Saba A.Gheni Safaa M.R.ahmed Mudheher M.Ali Hamid Yonis Saleh mohammed H.mohammed Awad E.mohammed Marwan A.Mahomood Hiba R.mohammed ahmed A.Hassan Adam Harvey North Refineries Company Ministry of OilIraq Chemical Engineering Department Tikrit UniversityIraq Ministry of Oil Iraq AL-Hawija Technical Institute Northern Technical UniversityMoselIraq School of Engineering Newcastle UniversityUK

To meet the rapidly increasing demand for energy and the dramatic depletion of conventional crude oil,it is imperative to utilize sour *** no coke being produced,oxidative desulfurization(ODS)of naphtha lowers its sulfur content and average molecular *** this article,we outline a method for heavy naphtha non-extractive ODS using a very stable *** technique involves the use of a solid catalyst with oxygen gas as the *** necessitated relatively high mixing intensities;hence a three-phase Oscillatory Baffled Reactor(OBR)was *** catalyst was based on the zeolite ZSM-5,prepared from natural kaolin by a series of delamination and activation steps and impregnated with Fe.A TiO2 nanolayer was applied,using the sol-gel method,to prevent rapid *** reactor performance was evaluated to minimize the sulfur content in the naphtha *** to the protective coating,the sulfur conversion stabilized at 90%.The results of this work establish the use of natural clay-based catalysts in a continuous,three-phase ODS,particularly with regard to proving long-term *** also showed that modest ODS can be achieved using an environmentally friendly oxidant,at mild operating conditions,whilst maintaining stability.

关键词： Natural kaoline Desulfurization Three-phase Oscillatory baffled reactor

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

Effectiveness of external prestressing in enhancing the non-ductile hanger failure mechanism in reinforced concrete inverted T-beams

引用

Frontiers of Structural and Civil Engineering 2024年第7期18卷 1050-1065页

作者： ahmed M.ATTA Reda N.BEHIRY mohammed I.HARAZ Structural Engineering Department Faculty of EngineeringTanta UniversityTanta 33511Egypt Nile Higher Institute for Engineering and Technology Mansoura 11001Egypt

Recently,inverted T-beams have been used in reinforced concrete(RC)bridges to support transverse precast *** T-beams,contrary to practice with conventional beams,are loaded on the flanges upper *** loading configuration causes hanger failure due to the generation of vertical tensile stresses near the bottom of the *** key purpose of this study is to investigate the efficiency of vertical external prestressing stainless-steel bars in mitigating non-ductile hanger failure in reinforced concrete inverted *** experimental study on six inverted-T beams,including two un-strengthened specimens,was carried *** study showed that the value of the prestressing level had a considerable impact on the performance of hanger mechanism in relation to crack pattern,ultimate loads,cracking behavior,load-deflection,strains,and *** experimental results indicated that the suggested method for strengthening inverted T-beams had efficacy in reducing the seriousness of the non-ductile hanger failure and resulted in a strength increase of up to 53% when compared to that of the un-strengthened ***,two analytical models for estimating the hanger capacity and the average crack width of the strengthened RC inverted T-beams were *** models that were proposed exhibited a high degree of agreement with the experimental results.

关键词： RC bridges inverted T-beams strengthening hanger failure external prestressing

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

Catalytic Effect of Transition Metal Complexes of Triaminoguanidine on the Thermolysis of Energetic NC/DEGDN Composite

引用

火炸药学报 2024年第3期47卷 209-219,I0003页

作者： mohammed Dourari ahmed Fouzi Tarchoun Djalal Trache Amir Abdelaziz Roufaida Tiliouine Tessnim Barkat Weiqiang Pang Energetic Materials Laboratory(EMLab) Teaching and Research Unit of Energetic ProcessesEcole Militaire PolytechniqueBP 17Bordj El-Bahri16046AlgiersAlgeria Xi′an Modern Chemistry Research Institute Xi′an 710065China

The transition metal complexes of triaminoguanidine(TAG-M,where M=Cobalt(Co)or Iron(Fe))have been *** catalytic effect of these complexes on the thermolysis of energetic composite based on nitrocellulose and diethylene glycol dinitrate,has been *** characterization of the resulting energetic composites was carried out using scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),and differential scanning calorimetry(DSC).Isoconversional kinetic analysis was performed to determine the Arrhenius parameters associated with the thermolysis of the elaborated energetic *** is found that TAG-M complexes have strong catalytic effect on the thermo-kinetic decomposition of NC/DEGDN by decreasing the apparent activation energy and significantly increased the total heat *** models that govern the decomposition processes are also studied,and it is revealed that different reaction processes are accomplished by introduction metal complexes of ***,this study serves as a valuable reference for future research focused on the investigation of catalytic combustion features of solid propellants.

关键词： triaminoguanidine transition metal complexes nitrocellulose diethylene glycol dinitrate catalytic effect

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

The impact of foot reflexology on fatigue and sleep quality in school-aged children undergoing hemodialysis

引用

Journal of Integrative Nursing 2024年第2期6卷 76-82页

作者： Amal Hashem MOHAMED Mostafa SHABAN Huda hamdy mohammed Randa Mohamed ABOBAKER Salman Hamdan ALSAQRI Rania Abd-Elnaby mohammed ALLAM Faculty of Nursing Minia UniversityMinyaEgypt College of Nursing Jouf UniversitySakakaSaudi Arabia Faculty of Nursing Cairo UniversityGizaEgypt Northern College of Nursing ARARSaudi Arabia College of Nursing University of HailHailSaudi Arabia

Objective:This study aimed to evaluate the effects of foot reflexology on fatigue and sleep quality in school-aged children receiving ***:A quasi-experimental pretest-posttest design was *** children of ages 6-12 undergoing in-center hemodialysis were *** Pittsburgh Sleep Quality Index(PSQI)and Inventory of Fatigue Symptom(IFS)scales were administered at *** then received 30 min of foot reflexology massage before hemodialysis sessions 3 days per week for 12 *** administration of the sleep and fatigue scales occurred after the intervention ***:Reflexology massage led to significant improvements in sleep quality components,including duration(0%-30%normal sleepers),efficiency(0%-50%>85%),latency(50%-0%>60 min),disturbances,and daytime *** mean PSQI score decreased from 18.2 to 9.7(P<0.05).Fatigue severity substantially decreased,with the mean IFS score improving from 105.7 to 64.1(P<0.05).Conclusion:Foot reflexology is an effective nursing intervention for reducing fatigue and improving sleep quality in children on hemodialysis,warranting integration into routine care.

关键词： Fatigue hemodialysis massage pediatric reflexology sleep

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

Impact of auditory stimulation nursing protocol on auditory response in cerebrovascular stroke patients

引用

Journal of Integrative Nursing 2024年第2期6卷 111-116页

作者： mohammed ElSayed ZAKY Hanan ahmed AL SEBAEE Nagat El Morsy IBRAHIEM Heba ahmed mohammed Mohammad Edrees MOHAMMAD Department of Medical Surgical Nursing Faculty of NursingCairo UniversityCairoEgypt Department of Neurology Faculty of MedicineCairo UniversityCairoEgypt

Objectives:The objective of the study was to explore the impact of auditory stimulation protocol on auditory response in cerebrovascular stroke(CVS)*** and Methods:A pre-posttest nonequivalent control group quasi-experimental study was conducted at Al Mainal Hospital at Al Kars Einy Hospital,Cairo University,among 60 CVS patients,and the sample was randomly assigned through a coin to allocate subjects to study or control group(30 for each group).Auditory stimulation techniques were applied three times per week for the study group for two consecutive *** in the control group received only routine hospital care during the study *** Glasgow Coma Scale(GCS)score for assessing the neurological function and level of arousal and the auditory subscale score of Western Neuro Sensory Stimulation Profile(WNSSP)for assessing auditory response were recorded and compared between the two groups before and after the ***:There were statistically significant differences between the study group and the control group regarding third reading of GCS score(11.5±0.3 vs.10.6±0.9,t=4.676,P=0.000).The scores of all auditory subscales of WNSSP in the study groups increased after implementing the auditory stimulation protocol(P<0.05).Conclusion:Utilizing the auditory stimulation protocol by nurse proves to be an effective method for enhancing hearing responses in individuals with CVS.

关键词： Auditory stimulation techniques hearing response nursing management stroke

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

Challenges to establishing and maintaining kidney transplantation programs in developing countries:What are the coping strategies?

引用

World Journal of Methodology 2024年第2期14卷 1-16页

作者： Rabea ahmed Gadelkareem Amr Mostafa Abdelgawad Nasreldin mohammed mohammed Ali Zarzour mahmoud Khalil ahmed Reda Hisham Mokhtar Hammouda Department of Urology Assiut Urology and Nephrology HospitalFaculty of MedicineAssiut UniversityAssiut 71515Egypt

Kidney transplantation(KT)is the optimal form of renal replacement therapy for patients with end-stage renal ***,this health service is not available to all patients,especially in developing *** deceased donor KT programs are mostly absent,and the living donor KT centers are ***-center studies presenting experiences from developing countries usually report a variety of *** review addresses these challenges and the opposing strategies by reviewing the single-center experiences of developing *** financial challenges hamper the infrastructural and material availability,coverage of transplant costs,and qualification of medical *** sociocultural challenges influence organ donation,equity of beneficence,and regular follow-up *** interests and motives for transplantation may result from high medicolegal responsibilities in KT practice,intense potential psychosocial burdens,complex qualification protocols,and low productivity or compensation for KT *** medical literacy about KT advantages is prevalent among clinicians,patients,and the *** inefficient organizational and regulatory oversight is translated into inefficient healthcare systems,absent national KT programs and registries,uncoordinated job descriptions and qualification protocols,uncoordinated on-site investigations with regulatory constraints,and the prevalence of commercial KT *** challenges resulted in noticeable differences between KT services in developed and developing *** coping strategies can be summarized in two main mechanisms:The first mechanism is maximizing the available resources by increasing the rates of living kidney donation,promoting the expertise of medical personnel,reducing material consumption,and supporting the establishment and maintenance of KT *** latter warrants the expansion of the public sector and the elimination of non-ethical KT *** second mechanism is recru

关键词： Challenges Coping strategies Developing countries Kidney transplantation Low resources Single-center

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

RPL-Based IoT Networks under Decreased Rank Attack:Performance Analysis in Static and Mobile Environments

引用

Computers, Materials & Continua 2024年第1期78卷 227-247页

作者： Amal Hkiri Mouna Karmani Omar Ben Bahri ahmed mohammed Murayr Fawaz Hassan Alasmari Mohsen Machhout Physic Department Electronics and Micro-Electronics LaboratoryFaculty of Sciences of MonastirMonastir5000Tunisia Department of Science and Technology College of RanyahTaif UniversityP.O.Box 11099Taif21944Saudi Arabia

The RPL(IPv6 Routing Protocol for Low-Power and Lossy Networks)protocol is essential for efficient communi-cation within the Internet of Things(IoT)*** its significance,RPL’s susceptibility to attacks remains a *** paper presents a comprehensive simulation-based analysis of the RPL protocol’s vulnerability to the decreased rank attack in both static andmobilenetwork *** employ the Random Direction Mobility Model(RDM)for mobile scenarios within the Cooja *** systematic evaluation focuses on critical performance metrics,including Packet Delivery Ratio(PDR),Average End to End Delay(AE2ED),throughput,Expected Transmission Count(ETX),and Average Power Consumption(APC).Our findings illuminate the disruptive impact of this attack on the routing hierarchy,resulting in decreased PDR and throughput,increased AE2ED,ETX,and *** results underscore the urgent need for robust security measures to protect RPL-based IoT ***,our study emphasizes the exacerbated impact of the attack in mobile scenarios,highlighting the evolving security requirements of IoT networks.

关键词： RPL decreased rank attacks mobility random direction model

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

Ultralong hydroxyapatite-based forward osmosis membrane for freshwater generation

引用

Frontiers of Chemical Science and Engineering 2024年第9期18卷 37-49页

作者： Mohamed Gamal Gomaa hamdy Maamoun Abdel-Ghafar Francesco Galiano Francesca Russo Alberto Figoli El-Sayed Ali Abdel-Aal Abdel-Hakim Taha Kandil Bahaa ahmed Salah Central Metallurgical Research and Development Institute(CMRDI) 11421 CairoEgypt Chemistry Department Faculty of ScienceHelwan University11795 CairoEgypt Institute on Membrane Technology(CNR-ITM) 87036 RendeItaly

Increasing global water shortages are accelerating the pace of membrane manufacturing,which generates many environmentally harmful *** challenges need a radical rethink of developing innovative membranes that can address freshwater production without generating environmentally harmful *** work utilized the synthesized ultra-long hydroxyapatite(UHA)by the solvothermal method using the green solvent oleic acid in preparing UHA-based forward osmosis *** membranes were developed using different loading ratios of graphene oxide(GO)by vacuum-assisted filtration *** prepared GO/UHA membranes were identified using X-ray diffraction,scanning electron microscope,Fourier-transform infrared spectroscopy,and X-ray photoelectron *** contact angle and pore size distribution were determined for the obtained GO/UHA *** obtained hierarchical porous structure in the prepared membranes with interconnected channels results in a stable water flux with reverse salt *** best water flux rate of 42±2 L·m^(–2)·h^(–1)was achieved using the 50 mg GO/UHA membrane,which is 3.3 times higher than the pristine membrane,and a reverse salt flux of 67 g·m^(-2)·h^(–1).The obtained results showed a promising capability of a new generation of sustainable inorganic-based membranes that can be utilized in freshwater generation by energy-efficient techniques such as forward osmosis.

关键词： forward osmosis ultra-long hydroxyapatite graphene oxide inorganic-based membrane

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

Phishing Attacks Detection Using EnsembleMachine Learning Algorithms

引用

Computers, Materials & Continua 2024年第7期80卷 1325-1345页

作者： Nisreen Innab ahmed Abdelgader Fadol Osman mohammed Awad mohammed Ataelfadiel Marwan Abu-Zanona Bassam Mohammad Elzaghmouri Farah H.Zawaideh Mouiad Fadeil Alawneh Department of Computer Science and Information Systems College of Applied SciencesAlmaarefa UniversityDiriyahRiyadh13713Saudi Arabia Applied College King Faisal UniversityAl-Ahsa31982Saudi Arabia Department of Management Information Systems College of Business AdministrationKing Faisal UniversityAl-Ahsa31982Saudi Arabia Department of Computer Science Faculty of Computer Science and Information TechnologyJerash UniversityJerash26110Jordan Department of Business Intelligence and Data Analysis Faculty of Financial Sciences and BusinessIrbid National UniversityIrbid21110Jordan Faculty of Information Technology Ajloun National UniversityAjloun26767Jordan

Phishing,an Internet fraudwhere individuals are deceived into revealing critical personal and account information,poses a significant risk to both consumers and web-based *** indicates a persistent rise in phishing ***,these fraudulent schemes are progressively becoming more intricate,thereby rendering them more challenging to ***,it is imperative to utilize sophisticated algorithms to address this *** learning is a highly effective approach for identifying and uncovering these harmful *** learning(ML)approaches can identify common characteristics in most phishing *** this paper,we propose an ensemble approach and compare it with six machine learning techniques to determine the type of website and whether it is normal or not based on two phishing *** that,we used the normalization technique on the dataset to transform the range of all the features into the same *** findings of this paper for all algorithms are as follows in the first dataset based on accuracy,precision,recall,and F1-score,respectively:Decision Tree(DT)(0.964,0.961,0.976,0.968),Random Forest(RF)(0.970,0.964,0.984,0.974),Gradient Boosting(GB)(0.960,0.959,0.971,0.965),XGBoost(XGB)(0.973,0.976,0.976,0.976),AdaBoost(0.934,0.934,0.950,0.942),Multi Layer Perceptron(MLP)(0.970,0.971,0.976,0.974)and Voting(0.978,0.975,0.987,0.981).So,the Voting classifier gave the best *** in the second dataset,all the algorithms gave the same results in four evaluation metrics,which indicates that each of them can effectively accomplish the prediction ***,this approach outperformed the previous work in detecting phishing websites with high accuracy,a lower false negative rate,a shorter prediction time,and a lower false positive rate.

关键词： Social engineering attacks phishing attacks machine learning security artificial intelligence

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

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：