检索结果-南通市图书馆

Response of slope surface roughness to wave-induced erosion during water level fluctuating

Journal of Mountain Science 2020年第4期17卷 871-883页

作者： GU Ju LIU Gang abd elBASIT Mohamed ahmed Mohamed SHI Hong-qiang State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China Agricultural Research Council Institute for SoilClimate&WaterPrivate Bag X79Pretoria 0001South Africa

The bank slopes in hydro-fluctuation areas of reservoirs or lakes suffer from severe erosion due to an absence of protection. Waves are one of the important external forces that cause bank erosion and slope failures. However, the processes and quantified impacts of wave-induced erosion on slopes remain unclear under different water level-fluctuation conditions. This paper focuses on the characteristics of wave-induced slope erosion under three conditions: water level dropping(WLD), fixed(WLF) and rising(WLR). A steel tank with glass pane was used to simulate the wave-induced slope erosion in the three treatments. The slope elevation data were collected by using the method of the pin meter for every 15 minutes from the beginning to the end, a total of 5 times during all treatments. These data were processed by using software(SURFER 9.0) to get the slope micro-topography and the erosion volume. Then the temporal and spatial change of slope erosion was analysed according to the erosion amount or erosion rate calculated based on bulk density of slope soil. The results demonstrated that the soil erosion rates for different water level changing treatments are in the following order: WLR>WLD>WLF. For the erosion spatial variation, the middle part of the slope was the major source of sediment in the WLD. The upper part of the slope was the major source of the sediment for the other two treatments. Compared with the standard deviation(SD), the coefficient of variation(CV) based on the SD is more representative of variations in the soil surface roughness(SSR). Furthermore, the good fit between the SSR and soil erosion rate have the potential to be used to predict soil erosion. Above all, the injection angle of the wave determined the rate of erosion to some extent, and the fall-back flow of the wave could also influence the extent of erosion, deposition, and bank morphology. It is vital to choose the appropriate index(SD or CV) in the three water levels to improve the predict

关键词： Bank erosion Erosion rate Micro topography Soil surface roughness Breaking point

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

Role of diabetes mellitus on the recurrence rate of hepatocellular carcinomas after radiofrequency ablation in chronic hepatitis C patients

引用

Hepatoma Research 2015年第1期1卷 24-29页

作者： abd Allah ahmed el-Sawy Mohamed abd el-Raouf Tawfik Hepatogastroenterology and Endoscopy Unit Internal Medicine DepartmentTanta University HospitalTanta 31527Egypt

Aim:The aim was to assess the impact of hyperglycemia on the recurrence of hepatocellular carcinoma(HCC)as well as evaluate survival after curative ablation by ***:This study,which was conducted retrospectively on 107 chronic hepatitis C(CHC)patients with 159 HCCs,was presented to the Hepatology Unit of Internal Medicine Department at Tanta University *** lesions were curatively treated by radiofrequency ablation(RFA)and the surveillance of HCC recurrence was evaluated radiologically every 3 months for periods between 6 and 36 *** 107 subjects,70 were males and 37 were females,with mean age 50.4±9.4 *** patients were divided according to their glycemic state into the following three groups:Group I,which included 37 type 2 diabetic patients,with adequate maintenance of blood glucose,has 52 HCCs;Group II,which included 25 type 2 diabetic patients with inadequate maintenance of blood glucose,has 43 HCCs;and Group III,which included 45 euglycemic non-diabetic patients,has 64 ***:Our results showed that,there was signifi cant increase in recurrence rate in diabetic patients with inadequate maintenance of blood glucose(Group II)compared to those in Group I and Group III(P<0.0001).Interestingly,there was no signifi cant difference concerning HCC recurrence between diabetic patients with adequate maintenance of blood glucose(Group I)and non-diabetic euglycemic patients(Group III).Our results also identifi ed that,inadequate maintenance of blood glucose in diabetic patients was also a signifi cant predictor of poor ***:Inadequate maintenance of blood glucose in diabetic patients is a signifi cant risk factor for recurrence of HCC and for poor survival after curative RFA therapy in CHC patients.

关键词： Hepatocellular carcinoma hyperglycemia radio frequency ablation recurrence survival

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

Integration of Multi-Constellation GNSS Precise Point Positioning and MEMS-Based Inertial Systems Using Tightly Coupled Mechanization

引用

Positioning 2015年第4期6卷 81-95页

作者： Mahmoud abd Rabbou ahmed el-Rabbany Department of Civil Engineering Ryerson University Toronto Canada

We develop a new integrated navigation system, which integrates multi-constellations GNSS precise point positioning (PPP), including GPS, GLONASS and Galileo, with low-cost micro-electro-mechanical sensor (MEMS) inertial system, for precise positioning applications. To integrate GNSS and the MEMS-based inertial system, the process and measurement models are developed. Tightly coupled mechanism is adopted, which is carried out in the GNSS raw measurements domain. Both un-differenced and between-satellite single-difference (BSSD) ionosphere-free linear combinations of pseudorange and carrier phase GNSS measurements are processed. Rigorous models are employed to correct GNSS errors and biases. The GNSS inter-system biases are considered as additional unknowns in the integrated error state vector. The developed stochastic model for inertial sensors errors and biases are defined based on first order Gaussian Markov process. Extended Kalman filter is developed to integrate GNSS and inertial measurements and estimate inertial measurements biases and errors. Two field experiments are executed, which represent different real-world scenarios in land-based navigation. The data are processed by using our developed Ryerson PPP GNSS/MEMS software. The results indicate that the proposed integrated system achieves decimeter to centimeter level positioning accuracy when the measurement updates from GNSS are available. During complete GNSS outages the developed integrated system continues to achieve decimeter level accuracy for up to 30 seconds while it achieves meter-level accuracy when a 60-second outage is introduced.

关键词： GNSS GPS Galileo GLONASS MEMS PPP Tightly Coupled

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

Brain metabolic profile assessed by magnetic resonance spectroscopy in children with Down syndrome:Relation to intelligence quotient

引用

World Journal of Clinical Pediatrics 2023年第5期12卷 310-318页

作者： Nesreen Safwat el Feil Heba S elmahdy Rasha ahmed elmahdy ahmed abd-elbasset Aboelezz Heba S Dawoud Mohammed Al-Beltagi Department of Pediatrics Faculty of MedicineTanta UniversityTanta 31527Al GharbiaEgypt Department of Radiology University Medical CenterDr.Sulaiman Al-Habib Medical GroupManama 26671ManamaBahrain Department of Pediatrics University Medical CenterKing Abdulla Medical CityArabian Gulf UniversityManama 26671ManamaBahrain Department of Pediatrics University Medical CenterDr.Sulaiman Al-Habib Medical GroupManama 26671ManamaBahrain

BACKGROUND Down syndrome(DS)is one of the most common causes of intellectual *** with DS have varying intelligence quotient(IQ)that can predict their learning *** To assess the brain metabolic profiles of children with DS and compare them to standard controls,using magnetic resonance spectroscopy(MRS)and correlating the results with *** This case-control study included 40 children with DS aged 6-15 years and 40 age and sex-matched healthy children as *** was used to evaluate ratios of choline/creatine(Cho/Cr),N-acetyl aspartic acid/creatine(NAA/Cr),and myoinositol/creatine(MI/Cr(in the frontal,temporal,and occipital lobes and basal ganglia and compared to controls and correlated with *** Children with DS showed significant reductions in NAA/Cr and MI/Cr and a non-significant reduction in Cho/Cr in frontal lobes compared to ***,we observed significant decreases in NAA/Cr,MI/Cr,and Cho/Cr in the temporal and occipital lobes and basal ganglia in children with DS compared to ***,there was a significant correlation between IQ and metabolic ratios in the brains of children with *** Brain metabolic profile could be a good predictor of IQ in children with DS.

关键词： Children Down syndrome Magnetic resonance spectroscopy Metabolic profile Intelligence quotient

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

electrowinning of Copper Using Rotating Cylinder electrode Utilizing Lead Anode

引用

Engineering（科研） 2011年第4期3卷 340-358页

作者： Hesham Soliman ahmed abd el-Moneim 不详

The effect of lead anode, rotating cylinder electrode (RCE), amount of 1,2-dihydroxypropane (12-DHP), temperature and rotation on the electrowinning of copper from low concentration acidified copper sulphate solution has been investigated. Copper powder was electrodeposited onto RCE that made of pure copper. From cyclic voltammetry experiments, an empirical parameter called the departure percent, S, was obtained which may represent the stability of the organic additive in the given medium and under the experimental conditions. The inhibition percentage, P, was 0.00 - 89.91% depending on the experimental variables. P was affected by temperature and mole fraction of 12-DHP, while rotation did not show any influence on it. Values of activation energy of electrodeposition process, Ea, were found to be less than 28 kJ mol-1 indicating diffusion controlled process. The overall mass transfer correlations under the present conditions have been computed using the dimensional analysis method. The data were valid for 90 electrodeposited copper powder as well as deposits composition and crystallite size have been studied. Various crystallite sizes ranged 7.1 nm - 250.6 nm were obtained and characterized by EDS and XRD. Different topographs proved that the rate of copper electrodeposition increased by increasing deposition time, temperature and the speed of rotation. Also, they proved that the deposition rate decreased by adding 12-DHP to the solution. Therefore, the results obtained by SEM supported those achieved by measuring the limiting current density and follow the normal manner when organic solvents were added to the electrodeposition bath.

关键词： electrodeposition electrowinning Lead Anode Rotating Cylinder electrode (RCE) 1 2-Dihydroxypropane (12-DHP) Copper Powder

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

The Use of Hinged Craniotomy in Comparison to Cisternostomy for Avoiding Bone Flap Replacement Second Surgery in Cases of Decompressive Craniotomy in Traumatic Brain Injury

引用

Open Journal of Modern Neurosurgery 2019年第1期9卷 7-16页

作者： ahmed el-Fiki Ehab abd-Haleem Department of Neurosurgery Cairo University Cairo Egypt

Introduction: Acute post traumatic subdural hematoma is a clinical condition with increased morbidity and mortality despite the developments in neurosurgery and urgent intervention is required to have best clinical outcome. We will evaluate hinged craniotomy technique in terms of offering adequate brain decompression plus avoiding removal of bone flap which requires second replacement surgery in comparison to cisternostomy effect. Material and Methods: A prospective study was conducted over 30 patients with traumatic acute subdural hematoma presented to neurotrauma unit in Cairo University hospitals from January 2017 to February 2018, operated by hinged craniotomy plus evacuation of hematoma and duroplasty. We avoid rapping the head with elastic bandage post-operative. Generous subcutaneous dissection (5 - 7 cm) all around skin flap was done routinely. Effect of brain decompression was evaluated by measuring the level of brain in relation to skull in post-operative computerized topography. Results: Twenty-one patients operated with initial GCS less than eight. Ten cases (33%) show that cortical surface in relation to skull bone was at inner table, nine cases (30%) at diploid layer and two cases (6.7%) at outer table in post-operative CT brain. Twenty patients died (66.7%);eight patients (26.6%) became fully conscious and two patients (6.7%) had vegetative outcome. No re-operation was done in any of our patients. Conclusion: Hinged craniotomy may be a safe and effective alternative technique with comparable results to cisternotomy in cases of traumatic brain injury that require decompression to avoid second surgery, especially in centres lacking cisternostomy experience. Although gaining cisternostomy experience may help in other indications, future prospective studies with larger number are required.

关键词： Decompression Subdural Hematoma Cisternostomy Traumatic Brain Injury

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

PPP Accuracy Enhancement Using GPS/GLONASS Observations in Kinematic Mode

引用

Positioning 2015年第1期6卷 1-6页

作者： Mahmoud abd Rabbou ahmed el-Rabbany Department of Civil Engineering Ryerson University Toronto Canada

Commonly, kinematic PPP techniques employ un-differenced ionosphere-free linear combination of GPS observations. This, however, may not provide continuous solution in urban areas as a result of limited satellite visibility. In this paper, the traditional un-differenced as well as between-satellite single-difference (BSSD) ionosphere-free linear combinations of GPS and GLONASS measurements are developed. Except GLONASS satellite clock products, the final precise GPS and GLONASS satellites clock and orbital products obtained from the multi-GNSS experiment (MGEX) are used. The effects of ocean loading, earth tide, carrier-phase windup, sagnac, relativity, and satellite and receiver antenna phase-center variations are rigorously modeled. Extended Kalman filter (EKF) is developed to process the combined GPS/GLONASS measurements. A comparison is made between three kinematic PPP solutions, namely standalone GPS, standalone GLONASS, and combined GPS/ GLONASS solutions. In general, the results indicate that the addition of GLONASS observations improves the kinematic positioning accuracy in comparison with the standalone GPS PPP positioning accuracy. In addition, BSSD solution is found to be superior to that of the traditional un-diffe- renced model.

关键词： GPS GLONASS PPP Kalman Filter (KF)

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

Modified aquila optimizer for forecasting oil production

引用

Geo-Spatial Information Science 2022年第4期25卷 519-535页

作者： Mohammed A.A.Al-qaness ahmed A.Ewees Hong Fan Ayman Mutahar AlRassas Mohamed abd elaziz State Key Laboratory for Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina Systems University of Bisha Department of e-BishaKingdom of Saudi Arabia Department of Computer Damietta UniversityDamiettaEgypt School of Petroleum Engineering China University of Petroleum(East China)QingdaoChina Department of Mathematics Faculty of ScienceZagazig UniversityZagazigEgypt Artificial Intelligence Research Center(AIRC) Ajman UniversityAjman 346United Arab Emirates Faculty of Computer Science&Engineering Galala UniversitySuze 435611Egypt

Oil production estimation plays a critical role in economic plans for local governments and ***,many studies applied different Artificial Intelligence(AI)based meth-ods to estimate oil production in different *** Adaptive Neuro-Fuzzy Inference System(ANFIS)is a well-known model that has been successfully employed in various applica-tions,including time-series ***,the ANFIS model faces critical shortcomings in its parameters during the configuration *** this point,this paper works to solve the drawbacks of the ANFIS by optimizing ANFIS parameters using a modified Aquila Optimizer(AO)with the Opposition-Based Learning(OBL)*** main idea of the developed model,AOOBL-ANFIS,is to enhance the search process of the AO and use the AOOBL to boost the performance of the *** proposed model is evaluated using real-world oil produc-tion datasets collected from different oilfields using several performance metrics,including Root Mean Square Error(RMSE),Mean Absolute Error(MAE),coefficient of determination(R2),Standard Deviation(Std),and computational ***,the AOOBL-ANFIS model is compared to several modified ANFIS models include Particle Swarm Optimization(PSO)-ANFIS,Grey Wolf Optimizer(GWO)-ANFIS,Sine Cosine Algorithm(SCA)-ANFIS,Slime Mold Algorithm(SMA)-ANFIS,and Genetic Algorithm(GA)-ANFIS,***,it is compared to well-known time series forecasting methods,namely,Autoregressive Integrated Moving Average(ARIMA),Long Short-Term Memory(LSTM),Seasonal Autoregressive Integrated Moving Average(SARIMA),and Neural Network(NN).The outcomes verified the high performance of the AOOBL-ANFIS,which outperformed the classic ANFIS model and the compared models.

关键词： Oil production ANFIS opposition-based learning(OBL) Aquila Optimizer(AO) time series forecasting Tahe oilfield Sunah oilfield

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

Some Notes on the Paper “New Common Fixed Point Theorems for Maps on Cone Metric Spaces”

引用

International Journal of Modern Nonlinear Theory and Application 2013年第2期2卷 150-151页

作者： Mohamed abd el-Rahman ahmed Department of Mathematics Faculty of Science Assiut University Assiut Egypt

In this paper, we show that Theorem 2.1 [1] (resp. Theorem 2.2 [1]) is a consequence of Corollary 2.1 [1] ( resp. Corollary 2.2 [1]).

关键词： Cone Metric Weakly Compatible Fixed Point

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

Assessment and Distribution of Heavy Metals Pollutants in Manzala Lake, Egypt

引用

Journal of Geoscience and Environment Protection 2015年第6期3卷 107-122页

作者： Mahmoud abd el-Kawy Zahran Yasser ahmed el-Amier abdelhamid ahmed elnaggar Hoda.abd el-Azim Mohamed Muhammad abd el-Hady el-Alfy Botany Department Faculty of Science Mansoura University Mansoura Egypt Soils Department Faculty of Agriculture Mansoura University Mansoura Egypt Marine Pollution Department National Institute of Oceanography and Fisheries Suez Egypt

Contamination with heavy metals is one of the most serious problems in the aquatic environments. In Egypt, Manzala Lake is suffering from this problem. The objective of this work was to assess heavy metals pollutants and their spatial distribution in Manzala Lake using GIS technique. Georeferenced water and sediment samples were randomly collected from the lake. The detected heavy metals were: Fe, Pb, Cu, Cd, Cr, Zn and Co. The obtained results indicated that the highest concentrations of heavy metals were observed in the northeastern and the southern parts of the lake nearby drains. This could be attributed to industrial, agricultural and municipal wastes coming through the drains especially Bahr el-Baqar drain and the industrial wastes coming from Port Said drains. From the geo-accumulation index, it was noticed that the lake is more polluted with cadmium and lead in the hydrosoils samples. All metals in water are within the EPA standard limit except for cadmium. Geostatistics provides effective methods to quantify the contaminated waters and sediments which support decision-making about redevelopment scenarios or remediation techniques.

关键词： Manzala Lake Heavy Metals Indices Pollution GIS

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：