检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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

An Adjusted Gray Map Technique for Constructing Large Four-Level Uniform Designs

在线全文

学校读者我要写书评

暂无评论

Journal of systems science & Complexity 2023年第1期36卷 433-456页

作者： ELsAWAH A M VIsHWAkARMA G k.mohamed H s FANG kai-Tai Department of statistics and Data science Faculty of Science and TechnologyBeijing Normal University-Hong Kong Baptist University United International CollegeZhuhai 519087China Guangdong Provincial key Laboratory of Interdisciplinary Research and Application for Data science BNU-HKBU United International CollegeZhuhai 519087China Department of Mathematics Faculty of ScienceZagazig UniversityZagazig 44519Egypt Department of Mathematics&Computing Indian Institute of Technology DhanbadDhanbad 826004India College of Transportation and Civil Engineering Fujian Agriculture and Forestry UniversityFuzhou 350002China The key Lab of Random Complex structures and Data Analysis The Chinese Academy of SciencesBeijing 100190China

A uniform experimental design(UED)is an extremely used powerful and efficient methodology for designing experiments with high-dimensional inputs,limited resources and unknown underlying models.A UED enjoys the following two significant advantages:(i)It is a robust design,since it does not require to specify a model before experimenters conduct their experiments;and(ii)it provides uniformly scatter design points in the experimental domain,thus it gives a good representation of this domain with fewer experimental trials(runs).Many real-life experiments involve hundreds or thousands of active factors and thus large UEDs are *** large UEDs using the existing techniques is an NP-hard problem,an extremely time-consuming heuristic search process and a satisfactory result is not *** paper presents a new effective and easy technique,adjusted Gray map technique(AGMT),for constructing(nearly)UEDs with large numbers of four-level factors and runs by converting designs with s two-level factors and n runs to(nearly)UEDs with 2^(t−1)s four-level factors and 2tn runs for any t≥0 using two simple transformation *** justifications for the uniformity of the resulting four-level designs are given,which provide some necessary and/or sufficient conditions for obtaining(nearly)uniform four-level *** results show that the AGMT is much easier and better than the existing widely used techniques and it can be effectively used to simply generate new recommended large(nearly)UEDs with four-level factors.

关键词： Aberration adjusted Gray map technique Gray map technique Hamming distance moment aberration threshold accepting algorithm uniform design

Alcoholic hepatitis and concomitant hepatitis C virus infection

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2014年第34期20卷 11929-11934页

作者： mohamed shoreibah Bhupinderjit s Anand Ashwani k singal Division of Gastroenterology and Hepatology University of Alabama BirminghamBirminghamAL 35294-0012United States Department of Gastroenterology and Hepatology Michael DeBakey VA CenterBaylor College of MedicineHoustonTX 77030United States

Hepatitis C virus(HCV)infection and alcohol abuse are two most important causes of chronic liver disease in the United *** hepatitis is a unique clinical syndrome among patients with chronic and active alcohol abuse with a potential for high short-term *** 20%of patients presenting with alcoholic hepatitis have concomitant HCV *** from alcoholic hepatitis is increased in the presence of concomitant hepatitis C due to synergistic interaction between HCV and alcohol in causing hepatocellular *** prospective randomized studies are needed to develop guidelines on the use of corticosteroids among patients with alcoholic hepatitis and concomitant HCV *** impact of antiviral therapy on mortality and outcome in the setting of alcoholic hepatitis remains a novel area for future research.

关键词： Alcoholic liver disease Alcoholic hepatitis Hepatitis C virus infection Corticosteroids Transplantation

Preparation and Reactions of 2-Methyl-7-（3-methyl-5-oxo-1- phenyl-2-pyrazolin-4-yl）-5-arylthiazolo[3,2-a]- pyrimido[4,5-d]oxazin-4（5H）-one

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

Chinese Journal of Chemistry 2011年第7期29卷 1473-1482页

作者： Youssef, mohamed salah k. Abbady, mohamed s. Ahmed, Ragaa A. Omar, Ahmed A. Chemistry Department Faculty of Science Assiut University Assiut 71516 Egypt

Ethyl 7-amino-3-（3-methyl-5-oxo- 1-phenyl-2-pyrazolin-4-yl）-5-aryl-5H-thiazolo[3,2-a]pyrimidine-6-carboxy- late was hydrolyzed with an ethanolic sodium hydroxide and the sodium salt thus formed underwent cyclization with acetic anhydride to afford 2-methyl-7-（3-methyl-5-oxo-l-phenyl-2-pyrazolin-4-yl）-5-arylthiazolo[3,2-a]- pyrimido[4,5-d]oxazin-4（sH）-one. This compound was transformed to related heterocyclic systems via its reaction with various reagents. The biological activity of the prepared compounds was tested against Gram positive and Gram negative bacteria as well as yeast-like and filamentous fungi. They revealed in some cases excellent biocidal properties.

关键词： thiazolopyrimidooxazinone thiazolopyrimidopyrimidines antimicrobial activity

Constraints on the crustal structure beneath the sinai subplate,sE Mediterranean,from analysis of local and regional travel times

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

Geoscience Frontiers 2013年第2期4卷 213-222页

作者： mohamed k.salah Geology Department Faculty of ScienceTanta UniversityTanta 31527Egypt

The sinai Peninsula has been recognized as a subplate of the African Plate located at the triple junction of the Gulf of suez rift,the Dead sea Transform fault,and the Red sea *** upper and lower crustal structures of this tectonically active,rapidly developing region are yet poorly understood because of many *** this reason,a set of P- and s-wave travel times recorded at 14 seismic stations belonging to the Egyptian National seismographic Network（ENsN） from 111 local and regional events are analyzed to investigate the crustal structures and the locations of the seismogenic zones beneath central and southern *** the velocity model used for routine earthquake location by ENsN is one-dimensional,the travel-time residuals will show lateral heterogeneity of the velocity structures and unmodeled vertical *** activity is strong along the eastern and southern borders of the study area but low to moderate along the northern boundary and the Gulf of suez to the *** crustal V_P/V_s ratio is 1.74 from shallow（depth≤10 km） earthquakes and 1.76 from deeper（depth 〉 10 km） crustal *** majority of the regional and local travel-time residuals are positive relative to the Preliminary Reference Earth Model（PREM）,implying that the seismic stations are located above widely distributed,tectonically-induced low-velocity *** low-velocity zones are mostly related to the local crustal faults affecting the sedimentary section and the basement complex as well as the rifting processes prevailing in the northern Red sea region and the ascending of hot mantle materials along crustal *** delineation of these low-velocity zones and the locations of big crustal earthquakes enable the identification of areas prone to intense seismotectonic activities,which should be excluded from major future development projects and large constructions in central and southern sinai.

关键词： Crustal structure sinai Peninsula sE Mediterranean seismicity Travel-time residuals(TTRs) Crustal V_P/V_s ratio

Upper crustal structure beneath southwest Iberia north of the convergent boundary between the Eurasian and African plates

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2014年第6期5卷 845-854页

作者： mohamed k.salah Geology Department Faculty of ScienceTanta UniversityTanta 31527Egypt

The 3-D P- and s-wave velocity models of the upper crust beneath southwest Iberia are determined by inverting arrival time data from local earthquakes using a seismic tomo^raphy method. We used a total of 3085 P- and 2780 s-wave high quality arrival times from 886 local earthquakes recorded by a per- manent seismic network, which is operated by the Institute of Meteorology （IM）, Lisbon, Portugal. The computed P- and s-wave velocities are used to determine the 3-D distributions of Vp/Vs ratio. The 3-D velocity and Vp/Vs ratio images display clear lateral heterogeneities in the study area. significant veloc- ity variations up to ~6% are revealed in the upper crust beneath southwest lberia, At 4 km depth, both P- and s-wave velocity take average to high values relative to the initial velocity model, while at 12 km, low P-wave velocities are clearly visible along the coast and in the southern parts. High s-wave velocities at 12 km depth are imaged in the central parts, and average values along the coast; although some scattered patches of low and high s-wave velocities are also revealed. The Vp/Vs rztio is generally high at depths of 4 and 12 km along the coastal parts with some regions of high Vp/Vs ratio in the north at 4 km depth, and low Vp/Vs ratio in the central southern parts at a depth of 12 km, The imaged low velocity and high Vp/Vs ratios are related to the thick saturated and unconsolidated sediments covering the region; whereas the high velocity regions are generally associated with the Mesozoic basement rocks.

关键词： Upper crustal structure southwest (sW) lberiaLoca Lseismic tomography Crustal Vp/Vs ratio

Exploration of structural,optical,and photoluminescent properties of (1-x)NiCo_(2)O_(4)/xPbs nanocomposites for optoelectronic applications

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第6期31卷 663-670页

作者： Zein k Heiba mohamed Bakr mohamed Noura M Farag Ali Badawi Physics Department Faculty of ScienceAin Shams UniversityCairoEgypt Physics Department Faculty of ScienceTaibah UniversityAl-Madina al MunawarahSaudi Arabia Department of Physics College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia Department of Physics University College of TurabahTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia

The(1-x)NiCo_(2)O_(4)/x Pbs(0≤x≤0.2)nanocomposite samples are synthesized using the hydrothermal and thermolysis *** different phases developed in the obtained nanocomposite samples are accurately determined using the x-ray diffraction technique equipped with a *** percentage of the formed phases(NiCo_(2)O_(4)(NCO),Pbs,PbsO_(4)),structural and microstructure parameters are determined using Rietveld quantitative phase *** transmission electron microscope(TEM)images and Rietveld analysis reveal almost isotropic particle size in the nano range with a very narrow size *** obtained phase percentage of Pbs and PbsO4are smaller than nominated values(x)suggesting dissolving of some Pb and s ions into NCO which is then confirmed by the analysis of Fourier-transform infrared(FTIR)spectra of nanocomposite *** absorption spectra are modified upon doping NCO with *** optical band gaps of the nanocomposites increase as the amount of Pbs *** effect of alloying on extinction coefficient,refractive index,dielectric constant,optical conductivity,the intensity,and emitted color from the photoluminescence of the nanocomposite samples are also *** refractive index value of NCO and NCO-Pbs nanocomposite samples exhibit normal *** photoluminescent measurements reveal that the NCO-Pbs nanocomposites can emit a violet *** improvement in the values of the nonlinear optical(NLO)parameters of pristine NCO at high frequencies or the nanocomposite samples at low frequencies,are made them used in NLO photonic devices.

关键词： Co_(2)O_(4)and Pbs nanocomposite FTIR optical photoluminescence

series solution of a natural convection flow for a Carreau fluid in a vertical channel with peristalsis

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2015年第6期27卷 969-979页

作者： ABD ELMABOUD Y. MEkHEIMER kh.s. mohamed mohamed s. Mathematics Department Faculty of Science and ArtsKhulaisUniversity Of Jeddah Mathematics Department Faculty of ScienceAl-Azhar University(Assiut Branch) Mathematics Department Faculty of ScienceTaif University Hawia Mathematics Department Faculty of ScienceAl-Azhar University

An analysis has been achieved to study the natural convection of a non-Newtonian fluid （namely a Carreau fluid） in a vertical channel with rhythmically contracting walls. The Navier-stokes and the energy equations are reduced to a system of non- linear PDE by using the long wavelength approximation. The optimal homotopy analysis method （OHAM） is introduced to obtain the exact solutions for velocity and temperature fields. The convergence of the obtained OHAM solution is discussed explicitly. Numerical calculations are carried out for the pressure rise and the features of the flow and temperature characteristics are analyzed by plotting graphs and discussed in detail.

关键词： homotopy analysis method (HAM) peristaltic transport carreau fluid heat transfer natural convection flow

Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling systems

在线全文

学校读者我要写书评

暂无评论

structural Durability & Health Monitoring 2025年第1期19卷 77-103页

作者： sabrina Meddah sid Ahmed Tadjer Abdelhakim Idir kong Fah Tee mohamed Zinelabidine Doghmane Madjid kidouche Applied Automation Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering Department Mohamed Boudiaf University of M’silaM’sila28000Algeria Department of Civil and Environmental Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building Materials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is *** study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm to the system’s components since they are difﬁcult to be detected and controlled in real *** study investigates the dynamic interactions of these vibrations,speciﬁcally in their high-frequency modes,usingﬁeld data obtained from measurement while ***ﬁndings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem *** obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control ***,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect ***,by exploiting theseﬁndings,the assessment of structural resilience in rotary drilling systems can be ***,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efﬁciency of rotary drilling systems in the petroleum industry.

关键词： Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis ﬁeld data analysis