检索结果-南通市图书馆

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

织造过程中织物面密度的在线控制

国际纺织导报 2013年第12期41卷 26-28页

作者： Y-S.Gloy t.islam R.Büllesfeld M.A.Raina t.Gries 傅本胜亚琛工业大学纺织技术研究所

利用X射线传感器实现织造过程中对织物面密度的监测和控制是可行的。通常,传感器的位置会对滞后时间产生显著影响,故本研究采用了Smith预估器。结果显示,监控效果显著,在不到30 s的时间里便能达到预期的织物面密度,且误差不超过3%。

关键词： X射线传感器织物面密度滞后时间 Smith预估器

Improved prediction of shear wave velocity for clastic sedimentary rocks using hybrid model with core data

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1466-1477页

作者： Mohammad islam Miah Department of Petroleum and Mining Engineering Chittagong University of Engineering and TechnologyChittagong4349Bangladesh

Accurate measurement of acoustic velocities of sedimentary rocks is essential for prediction of rock elastic constants and well failure analysis during drilling *** measurement by advanced logging tools such as dipole sonic imager is not always *** older wells,such data are not available in most ***,it is an alternate way to develop a reliable correlation to estimate the shear wave velocity from existing log and/or core *** objective of this research is to investigate the nature of dependency of different reservoir parameters on the shear wave velocity(VS) of clastic sedimentary rocks,and to identify the parameter/variable which shows the highest level of *** the study,data-driven connectionist models are developed using machine learning approach of least square support vector machine(LSSVM).the coupled simulated annealing(CSA) approach is utilized to optimize the tuning and kernel parameters in the model *** performance of the simulation-based model is evaluated using statistical *** is found that the most dependency predictor variable is the compressional wave velocity,followed by the rock porosity,bulk density and shale volume in turn.A new correlation is developed to estimate VS,which captures the most influential parameters of sedimentary *** new correlation is verified and compared with existing models using measured data of sandstone,and it exhibits a minimal error and high correlation coefficient(R^(2)-0.96).the hybridized LSSVM-CSA connectionist model development strategy can be applied for further analysis to predict rock mechanical ***,the improved correlation of VS can be adopted to estimate rock elastic constants and conduct wellbore failure analysis for safe drilling and field development decisions,reducing the exploration costs.

关键词： Machine learning Acoustic shear velocity Elastic constants Rock strength Geomechanics

General Cosmological Solutions of Einstein's Equations for Spherical, Plane and Hyperbolic Symmetric Space

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2000年第2期17卷 79-81页

作者： Mohammed Ashraful islam Department of Mathematics and RCMPS Chittagong UniversityChittagongBangladesh

the analytic cosmological solutions of Einstein's field equations for a type of static metric representing plane, spherical and hyperbolic symmetric spaces are presented and their properties are discussed separately. A general type of solution is obtained which represents the plane, spherical and hyperbolic symmetric cosmological models. Its physical properties are also discussed in details.

关键词： Einstein hyperbolic symmetric

Effects of loading rate and hydraulic residence time on anoxic sulfide biooxidation

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

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第7期8卷 1149-1156页

作者： MAHMOOD Qaisar islam Ejazul Department of Environmental Engineering Zhejiang University

the optimal operation conditions in an anoxic sulfide oxidizing (ASO) bioreactor were investigated. the maximal removal rates for sulfide and nitrate were found to be 4.18 kg/(m3·d) and 1.73 kg/(m3·d), respectively. the volumetrical volumetric loading rates (LRs) observed through decreasing hydraulic retention time (HRt) at fixed substrate concentration are higher than those by increasing substrate concentration at fixed HRt. the sulfide oxidation in ASO reactor was partially producing both sulfate and sulfur; but the amount of sulfate produced was approximately one third that of sulfur. the process was able to tolerate high sulfide concentration, as the sulfide removal percentage always remained near 99% when influent concentration was up to 580 mg/L. It tolerated relatively lower nitrate concentration because the removal percentage dropped to 85% when influent con- centration was increased above 110 mg/L. the process can tolerate shorter HRt but careful operation is needed. Nitrate conversion was more sensitive to HRt than sulfide conversion since the process performance deteriorated abruptly when HRt was decreased from 3.12 h to 2.88 h. In order to avoid nitrite accumulation in the reactor, the influent sulfide and nitrate concentrations should be kept at 280 mg/L and 67.5 mg/L respectively. Present biotechnology is useful for removing sulfides from sewers and crude oil.

关键词： Anaerobic processes Anoxic nitrate removal Biodesulfurization Biotransformation Fluidized bed bioreactors Hydraulic residence time (HRt)

Spherically Symmetric Cosmological Solutions of Einstein’s Equations

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1999年第4期16卷 247-248页

作者： Mohammed Ashraful islam Department of Mathematics and Research Centre for Mathematical and Physical SciencesChittagong UniversityChittagongBangladesh

two sets of solution of the Einstein’s equations of general theory of relativity which is spherically-symmetric and nonstatic homogeneous isotropic universe for perfect fluid are *** first solution is the Einstein de-Sitter type containing a scale factor(√6πкGt+a)^(4/3)and an arbitrary function f(R)of radial space *** second solution is for stiff equation of state p=ρc2,which also has a scale factor[3√8πaG∫^(t)_(0)ξ(t)dt]^(2/3)and an arbitrary function h(R)of radial space coordinates.

关键词： Einstein arbitrary radial

An ab initio investigation of vibrational, thermodynamic, and optical properties of Sc_2AlC MAX compound

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 Physics B 2016年第10期25卷 103-108页

作者： M A Ali M t Nasir M R Khatun A K M A islam S H Naqib Department of Physics Chittagong University of Engineering and Technology Department of Arts & Sciences Bangladesh Army University of Science and Technology Department of Physics University of Rajshahi International islamic University Chittagong

the structural vibrational, thermodynamical, and optical properties of potentially technologically important, weakly coupled MAX compound, Sc2 Al C are calculated using density functional theory(DFt). the structural properties of ScAlC are compared with the results reported earlier. the vibrational, thermodynamical, and optical properties are theoretically estimated for the first time. the phonon dispersion curve is calculated and the dynamical stability of this compound is investigated. the optical and acoustic modes are observed clearly. We calculate the Helmholtz free energy(F), internal energy(E), entropy(S), and specific heat capacity(Cv) from the phonon density of states. Various optical parameters are also calculated. the reflectance spectrum shows that this compound has the potential to be used as an efficient solar reflector.

关键词： MAX compound phonon dispersion thermodynamical properties optical properties

Sensing and Uptake of Nitrogen in Rice Plant: A Molecular View

在线全文

学校读者我要写书评

暂无评论

Rice science 2019年第6期26卷 343-355页

作者： Md Saiful islam Department of Soil Science Patuakhali Science and Technology University Graduate School of Agricultural and Life Sciences The University of Tokyo

As a main feature of plant autotrophy, assimilation of inorganic nitrogen (N) is not only of fundamental interest to the crop, but also a crucial factor in crop productivity. N is the main plant mineral nutrient needed for chlorophyll production and other plant cell components (proteins, nucleic acids and amino acids). I highlighted the novel aspects of N responsive sensors, transporters and signaling molecules recently identified in the monocot rice plant, and discussed their potential roles in N sensing and transporting. Furthermore, over the last couple of years, N sensing has been shown to be affected by different external factors, which act as local signals to trigger systemic signaling coordinated by long-distance transport or mobile signals in plant body. Understanding of this complex regulatory network provides a foundation mechanism for the development of novel strategies to increase the acquisition and transportation efficiency of nitrogen under varying N conditions for rice production.

关键词： rice nitrate signaling gene function

Magnetic Field of a Compact Spherical Star under f(R,t) Gravity

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2018年第9期35卷 104-108页

作者： Safiqul islam Shantanu Basu Harish-Chandra Research Institute HBNI Department of Physics and Astronomy The University of Western Ontario

We present the interior solutions of distributions of magnetized fluid inside a sphere in f（R, t） gravity. tile magnetized sphere is embedded in an exterior Reissner NordstrOm metric. We assume that all physical quantities are in static equilibrium. the perfect fluid matter is studied under a particular form of the Lagrangian density f（R, t）. the magnetic field profile in modified gravity is calculated. Observational data of neutron stars are used to plot suitable models of magnetized compact objects. We reveal the effect of f（R, t） gravity on the magnetic field profile, with application to neutron stars, especially highly magnetized neutron stars found in x-ray pulsar systems. Finally, the effective potential Veff and innermost stable circular orbits, arising out of the motion of a test particle of negligible mass influenced by attraction or repulsion from the massive center, are discussed.

关键词： Gravity Magnetic Field of a Compact Spherical Star under f R,t

Morphology and microstructure characterization of 95W-3.5Ni-1.5Fe powder prepared by mechanical alloying

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and technology Beijing 2006年第5期13卷 442-445页

作者： islam S. Humail Key Laboratory for Advanced Metals and Materials Materials Science and Engineering SchoolUniversity of Science and Technology Beijing

the mechanism of mechanical solid-state reactions for formation of tungsten heavy alloy powder was discussed. A highenergy ball mill operating at room temperature was used for preparing tungsten heavy alloy powders, starting from elemental tungsten （W）, nickel （Ni）, and iron （Fe） powders. X-ray diffraction （XRD）, particle size analyzer, scanning electron microscopy （SEM）, and transmission electron microscopy （tEM） were used to follow the progress of the mechanical solid-state reaction of W, Ni, and Fe powders. these morphological studies revealed three stages in the milling process. In the first stage, the particle deformation changes the irregular structure of the as-received powder particles to flattened morphology, and the average particle size increases. In the second stage, the powder is sufficiently deformed and the tendency to fracture predominates over welding, and the particle size decreases. With continuous milling, the system reaches steady state, and relatively small and uniform particle size distribution is obtained after 20 h of milling.

关键词： tungsten heavy alloys mechanical alloying particle size morphology