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Intense supercontinuum generation in the near-ultraviolet range from a 400-nm femtosecond laser filament array in fused silica

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Chinese Physics B 2017年第7期26卷 149-152页

作者：李东伟张兰芝 saba Zafar 宋鹤郝作强奚婷婷高勋林景全 School of Science Changchun University of Science and Technology School of Physics University of Chinese Academy of Sciences

An intense supercontinuum（SC） in the near-ultraviolet range is generated from filamentation by focusing a 400-nm laser into fused silica with a microlens array（MLA）. The spectrum of the SC is shown to be sensitive to the distance between the MLA and fused silica. In our optimal conditions, the near-ultraviolet SC can cover a range of 350-600 nm,where a bandwidth of approximately 55 nm above the 1μJ/nm spectral energy density and 20 nm bandwidth with tens ofμJ/nm are achieved. In addition, the energy conversion efficiency of the 400 nm laser for SC generation is further analyzed.A maximum conversion efficiency of 66% is obtained when the entrance face of fused silica is set around the focus of the MLA.

关键词： filamentation supercontinuum generation microlens array fused silica

Image Fusion Using Wavelet Transformation and XGboost Algorithm

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Computers, Materials & Continua 2024年第4期79卷 801-817页

作者： Shahid Naseem Tariq Mahmood Amjad Rehman Khan Umer Farooq Samra Nawazish Faten S.Alamri Tanzila saba Department of Information Sciences Division of S&TUniversity of EducationLahore54770Pakistan Artificial Intelligence and Data Analytics(AIDA)Lab CCIS Prince Sultan UniversityRiyadh11586Saudi Arabia Faculty of Information Sciences University of EducationVehari CampusVehari61100Pakistan Department of Computer Science University of Engineering and TechnologyTaxila47050Pakistan Department of Mathematical Sciences College of SciencePrincess Nourah Bint Abdulrahman UniversityRiyadh84428Saudi Arabia

Recently,there have been several uses for digital image *** fusion has become a prominent application in the domain of imaging *** create one final image that provesmore informative and helpful compared to the original input images,image fusion merges two or more initial images of the same *** fusion aims to produce,enhance,and transform significant elements of the source images into combined images for the sake of human visual *** fusion is commonly employed for feature extraction in smart robots,clinical imaging,audiovisual camera integration,manufacturing process monitoring,electronic circuit design,advanced device diagnostics,and intelligent assembly line robots,with image quality varying depending on *** research paper presents various methods for merging images in spatial and frequency domains,including a blend of stable and curvelet transformations,everageMax-Min,weighted principal component analysis(PCA),HIS(Hue,Intensity,Saturation),wavelet transform,discrete cosine transform(DCT),dual-tree Complex Wavelet Transform(CWT),and multiple wavelet *** fusion methods integrate data from several source images of an identical target,thereby enhancing information in an extremely efficient *** precisely,in imaging techniques,the depth of field constraint precludes images from focusing on every object,leading to the exclusion of certain *** tackle thess challanges,a very efficient multi-focus wavelet decomposition and recompositionmethod is *** use of these wavelet decomposition and recomposition techniques enables this method to make use of existing optimized wavelet code and filter *** simulated outcomes provide evidence that the suggested approach initially extracts particular characteristics from images in order to accurately reflect the level of clarity portrayed in the original *** study enhances the performance of the eXtreme Gradient Boosting(XGBoos

关键词： Image fusion max-min average CWT XGBoost DCT inclusive innovations spatial and frequency domain

Chaos Behavior and Estimation of the Unknown Parameters of Stochastic Lattice Gas for Prey-Predator Model with Pair-Approximation

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Applied Mathematics 2016年第15期7卷 1765-1779页

作者： saba Mohammed Alwan Department of Mathematics and Computer Science Faculty of Science Ibb University Ibb Yemen

In this paper, the problem of chaos, stability and estimation of unknown parameters of the stochastic lattice gas for prey-predator model with pair-approximation is studied. The result shows that this dynamical system exhibits an oscillatory behavior of the population densities of prey and predator. Using Liapunov stability technique, the estimators of the unknown probabilities are derived, and also the updating rules for stability around its steady states are derived. Furthermore the feedback control law has been as non-linear functions of the population densities. Numerical simulation study is presented graphically.

关键词： Stochastic Lattice Gas Model Prey-Predator Updating Rules Estimation System State

Outsmarting Android Malware with Cutting-Edge Feature Engineering and Machine Learning Techniques

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Computers, Materials & Continua 2024年第4期79卷 651-673页

作者： Ahsan Wajahat Jingsha He Nafei Zhu Tariq Mahmood Tanzila saba Amjad Rehman Khan Faten S.A.lamri Faculty of Information Technology Beijing University of TechnologyBeijing100124China Artificial Intelligence and Data Analytics(AIDA)Lab CCIS Prince Sultan UniversityRiyadh11586Saudi Arabia Faculty of Information Sciences University of EducationVehari CampusVehari61100Pakistan Department of Mathematical Sciences College of SciencePrincess Nourah bint Abdulrahman UniversityRiyadh84428Saudi Arabia

The growing usage of Android smartphones has led to a significant rise in incidents of Android malware andprivacy *** escalating security concern necessitates the development of advanced technologies capableof automatically detecting andmitigatingmalicious activities in Android applications(apps).Such technologies arecrucial for safeguarding user data and maintaining the integrity of mobile devices in an increasingly digital *** methods employed to detect sensitive data leaks in Android apps are hampered by two major limitationsthey require substantial computational resources and are prone to a high frequency of false *** meansthat while attempting to identify security breaches,these methods often consume considerable processing powerand mistakenly flag benign activities as malicious,leading to inefficiencies and reduced reliability in *** proposed approach includes a data preprocessing step that removes duplicate samples,managesunbalanced datasets,corrects inconsistencies,and imputes missing values to ensure data *** Minimaxmethod is then used to normalize numerical data,followed by feature vector extraction using the Gain ratio andChi-squared test to identify and extract the most significant characteristics using an appropriate prediction *** study focuses on extracting a subset of attributes best suited for the task and recommending a predictivemodel based on domain expert *** proposed method is evaluated using Drebin and TUANDROMDdatasets containing 15,036 and 4,464 benign and malicious samples,*** empirical result shows thatthe RandomForest(RF)and Support VectorMachine(SVC)classifiers achieved impressive accuracy rates of 98.9%and 98.8%,respectively,in detecting unknown Androidmalware.A sensitivity analysis experiment was also carriedout on all three ML-based classifiers based on MAE,MSE,R2,and sensitivity parameters,resulting in a flawlessperformance for both *** app

关键词： Android malware detection machine learning SVC K-Nearest Neighbors(KNN) RF

Microstructure and anisotropic swelling behaviour of compacted bentonite/sand mixture

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Journal of Rock Mechanics and Geotechnical Engineering 2014年第2期6卷 126-132页

作者： Simona saba Jean-Dominique Barnichon Yu-Jun Cui Anh Minh Tang Pierre Delage Ecole des Ponts ParisTech Laboratoire Navier Institut de Radioprotection et de Surete Nucleaire(IRSN)

Pre-compacted elements （disks, tutus） of bentonite/sand mixture are candidate materials for sealing plugs of radioactive waste disposal. Choice of this material is mainly based on its swelling capacity allowing all gaps in the system to be sealed, and on its low permeability. When emplaced in the gallery, these elements will start to absorb water from the host rock and swell. Thereby, a swelling pressure will develop in the radial direction against the host rock and in the axial direction against the support structure. In this work, the swelling pressure of a small scale compacted disk of bentonite and sand was experimentally studied in both radial and axial directions. Different swelling kinetics were identified for different dry densities and along different directions. As a rule, the swelling pressure starts increasing quickly, reaches a peak value, decreases a little and finally stabilises. For some dry densities, higher peaks were observed in the radial direction than in the axial direction. The presence of peaks is related to the microstructure change and to the collapse of macro- pores. In parallel to the mechanical tests, microstructure investigation at the sample scale was conducted using microfocus X-ray computed tomography （BCT）. Image observation showed a denser structure in the centre and a looser one in the border, which was also confirmed by image analysis. This structure heterogeneity in the radial direction and the occurrence of macro-pores close to the radial boundary of the sample can explain the large peaks observed in the radial swelling pressure evolution. Another interesting result is the higher anisotropy found at lower bentonite dry densities, which was also analysed by means ofμCT observation of a sample at low bentonite dry density after the end of test. It was found that the macro-pores, especially those between sand grains, were not filled by swelled bentonite, which preserved the anisotropic microstructure caused by uniaxial compression

关键词： Bentonite/sand mixture Nuclear waste disposal Anisotropy Swelling pressure Microstructure Microfocus X-ray computed tomography(μCT)

Carrier multiplication in germanium nanocrystals

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Light(Science & Applications) 2015年第1期4卷 498-503页

作者： saba Saeed Chris de Weerd Peter Stallinga Frank CM Spoor Arjan J Houtepen Laurens DA Siebbeles Tom Gregorkiewicz Van der Waals-Zeeman Institute University of Amsterdam1098 XH AmsterdamThe Netherlands FCT-DEEI University of the Algarve8005-139 FaroPortugal Optoelectronic Materials Faculty of Applied SciencesDelft University of Technology2628 BL DelftThe Netherlands

Carrier multiplication is demonstrated in a solid-state dispersion of germanium nanocrystals in a silicon–dioxide *** is performed by comparing ultrafast photo-induced absorption transients at different pump photon energies below and above the threshold energy for this *** average germanium nanocrystal size is approximately 5–6 nm,as inferred from photoluminescence and Raman spectra.A carrier multiplication efficiency of approximately 190%is measured for photo-excitation at 2.8 times the optical bandgap of germanium nanocrystals,deduced from their photoluminescence spectra.

关键词： carrier multiplication germanium nanocrystals transient absorption

Structure Elucidation and Biological Screening of Bis(4-{[(E)-(2-Hydroxybenzylidene)amino]methyl}-cyclohexane-carboxylato-O)-triaqua-cadmium

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Chinese Journal of Structural Chemistry 2018年第6期37卷 871-877页

作者： MUHAMMAD Danish saba Akbar MUHAMMAD Nawaz Tahir MUHAMMAD Naeem Ahmed RABIA Ayub Butt MUHAMMAD Asam Raza MUHAMMAD Ashfaq Department of Chemistry University of Gujrat Department of Physics University of Sargodha Department of Chemistry University of Azad Jammu and Kashmir

Using a bidentate ligand, a Schiff base 4-（{[（Z）-（2-hydroxyphenyl）methyldene]amino}methyl）cyclohexanecarboxylic acid, complex I（ML2, where M = Cd（Ⅱ）） was synthesized and characterized by IR spectroscopy and X-ray crystallography. It crystallizes in monoclinic system, space group C2/c, M_r = 685.04, 0.34 mm × 0.26 mm × 0.14 mm, a = 54.050（3）, b = 6.1220（3）, c = 9.5081（5） A, β = 90.229（2）°, Z = 4, C_（30） H_（40） CdN_2 O_9 and V = 3146.2（3） A^3. Complex I was screened for its bactericidal activity against four bacterial strains Chromohalobactersalexigens, Chromohalobacterisraelensis, Halomonashalofila and Halomonassalina and fungicidal activity against Aspergillusnigerand Aspergillusflavus. Antimicrobial activity results showed that the synthesized complex displayed good anti-fungal activity against two fungal strains. It was found to be inactive against four different bacterial strains analyzed and was negative for bactericidal effect.

关键词： Schiff base tranexamic acid Cd XRD fungicidal activity bactericidal activity

Digital subtraction angiography for the analysis of supraaortic vessels: What is its role nowadays?

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World Journal of Radiology 2011年第6期3卷 147-151页

作者： Luca saba Department of Radiology Azienda Ospedaliero Universitariadi Cagliari-Polo di Monserrato s.s.554 Monserrato (Cagliari) 09045 Italy

For about 50 years, angiography represented the only imaging method for studying carotid arteries in order to detect the presence of pathological stenosis due to atherosclerotic plaque. Recently, thanks to the use of non-invasive methods, physicians are able to study and quantify the presence of carotid atherosclerosis in vivo These procedures have enabled the introduction of new concepts: (1) the degree of carotid stenosis is approxi- mate to the volume and extension of carotid plaque; and (2) a set of parameters, easily identifiable by com- puted tomography angiography, magnetic resonance angiogram and ultra-sound echo-color Doppler, are closely linked to the development of ischemic symptoms and can significantly increase the risk of stroke regard- less of the degree of stenosis. In light of these findings vulnerable plaques should be identified early, and the role of Digital Subtraction Angiography which is a purely technical luminal technique should be determined.

关键词： Carotid arteries Computed tomography an- giography Digital Subtraction Angiography

Flood Hazard Mapping of Lower Indus Basin Using Multi-Criteria Analysis

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Journal of Geoscience and Environment Protection 2016年第4期4卷 54-62页

作者： saba Zehra Sheeba Afsar Department of Geography University of Karachi Karachi Pakistan

Flooding has been one of the recurring occurred natural disasters that induce detrimental impacts on humans, property and environment. Frequent floods is a severe issue and a complex natural phenomenon in Pakistan with respect to population affected, environmental degradations, and socio-economic and property damages. The Super Flood, which hit Sindh in 2010, has turned out to be a wakeup call and has underlined the overwhelming challenge of natural calamities, as 2010 flood and the preceding flood in 2011 caused a huge loss to life, property and land use. These floods resulted in disruption of power, telecommunication, and water utilities in many districts of Pakistan, including 22 districts of Sindh. These floods call for risk assessment and hazard mapping of Lower Indus Basin flowing in the Sindh Province as such areas were also inundated in 2010 flood, which were not flooded in the past in this manner. This primary focus of this paper is the use of Multi-criteria Evaluation (MCE) methods in integration with the Geographical Information System (GIS) for the analysis of areas prone to flood. This research demonstrated how GIS tools can be used to produce map of flood vulnerable areas using MCE techniques. Slope, Aspect, Curvature, Soil, and Distance from Drainage, Land use, Precipitation, Flow Direction, and Flow Accumulation are taken as the causative factors for flooding in Lower Indus Basin. Analytical Hierarchy Process-AHP was used for the calculation of weights of all these factors. Finally, a flood hazard Map of Lower Indus Basin was generated which delineates the flood prone areas in the Sindh province along Indus River Basin that could be inundated by potential flooding in future. It is aimed that flood hazard mapping and risk assessment using open source geographic information system can serve as a handy tool for the development of land-use strategies so as to decrease the impact from flooding.

关键词： Flood Risk Assessment Flood Predictive Modeling Flood Hazard Map Geographic Information System