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Cohomology of Associative H-Pseudoalgebras

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Algebra Colloquium 2023年第4期30卷 541-554页

作者： José i.Liberati Ciem-CONiCET Medina Allende y Haya de la TorreCiudad Universitaria(5000)CórdobaArgentina

We define the cohomology of associative H-pseudoalgebras,and we show that it describes module extensions,abelian pseudoalgebra extensions,and pseudoalgebra first-order *** same results for the special case of associat... 详细信息

关键词： associative pseudoalgebra associative conformal algebra cohomology

Distortion Analysis of Single V-groove Butt Welding on Heat Treatable Aluminum Alloys

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Journal of Materials Science & Technology 2005年第5期21卷 738-742页

作者： i.K.Lee Department of Mechanical Engineering National Chiao Tung UniversityHsinchu TaiwanChina

in this study we conducted single V-groove butt welding （GTAW） on three types of heat treatable aluminum alloys 2024-T351, 6061-T6 and 7075-T6 and compared the angular distortion levels of the three aluminum alloys at different Vee preparation angles with or without restraint. Experimental results demonstrated that when the Vee preparation angle was 0° （i-shaped groove）, the angular distortion level of the restrained weldment can exceed that of the unrestrained weldments. Moreover, when the Vee preparation angle was 45°, 60° or 90°, the restrained weldment had lower angular distortion than the unrestrained weldments. The single Vee preparation angle （amount of filler metal） in butt welding affected the angular distortion of the weldment. Without restraint, the angular distortion tended to increase with the single Vee preparation angle. Meanwhile, the angular distortion tended to decrease when the single Vee preparation angle was 60% Additionally, a restrained weldment had high angular distortion when the single Vee preparation angle was 0°. Notably, the angular distortion tended to reduce with increasing single Vee preparation angle. The angular distortion of the weldment was minimized at an angle of 60°. However, the angular distortion increased when the Vee preparation angle exceeded 60% The high-temperature yield strength of a material also affected its angular distortion. Angular distortion increased with high-temperature yield strength. Experimental results also showed that, from the strongest to the weakest, the high-temperature yield strength of the three types of aluminum alloys followed the order 6061-T6 and 2024-T351〉7075-T6.

关键词： Angular distortion Aluminum alloy Single-V-groove

The current status and future development of high-temperature conventional superconductivity

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National Science Review 2024年第7期11卷 18-20页

作者： Mikhail i.Eremets High Pressure Chemistry and Physics Group Max-Planck-Institut für Chemie

This survey highlights key advancements in high-temperature superconductivity in hydrogen-rich materials, emphasizing the robust evidence and reproducibility of superconductivity under challenging experimental conditions of megabar pressures. in the near future, achieving room-temperature superconductivity is highly probable, and the field is expected to transition towards near-ambient-pressure superconductivity.

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Flat limit of the de Sitter QFT in the rest frame vacuum

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Chinese Physics C 2021年第1期45卷 97-108页

作者： ion i.Cotaescu West University of Timisoara V.Parvan Ave.4RO-300223 TimisoaraRomania

The problem of the flat limits of the scalar and spinor fields on the de Sitter expanding universe is considered in the traditional adiabatic vacuum and in the new rest frame vacuum we proposed recently,in which the frequencies are separated in the rest frames as in special *** is shown that only in the rest frame vacuum can the Minkowskian flat limit be reached naturally fbr any momentum,whereas in the adiabatic vacuum,this limit remains undefined in rest frames in which the momentum *** important role is played by the phases of the fundamental solutions in the rest frame vacuum,which must be regularized to obtain the desired Minkowskian flat *** procedure fixes the phases of the scalar mode functions and Dirac spinors,resulting in their definitive expressions derived *** physical consequenee is that,in the rest frame vacuum,the flat limits of the oneparticle operators are simply the corresponding operators of special relativity.

关键词： de Sitter space-time Klein-Gordon field Dirac field flat limit approximation method phase regularization

Self-phase modulation via similariton solutions of the perturbed NLSE Modulation instability and induced self-steepening

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Communications in Theoretical Physics 2022年第8期74卷 41-50页

作者： H i Abdel-Gawad Department of Mathematics Faculty of Science Cairo University Egypt

The perturbed nonlinear Schrodinger equation(PNLSE)describes the pulse propagation in optical fibers,which results from the interaction of the higher-order dispersion effect,self-steepening(SS)and self-phase modulation(SPM).The challenge between these aforementioned phenomena may lead to a dominant one among *** is worth noticing that the study of modulation instability(Mi)leads to the inspection of dominant phenomena(DPh).indeed,the Mi triggers when the coefficient of DPh exceeds a critical value and it may occur that the interaction leads to wave *** PNLSE is currently studied in the literature,mainly on finding traveling wave ***,we are concerned with analyzing the similarity solutions of the *** exact solutions are obtained via introducing similarity transformations and by using the extended unified *** solutions are evaluated numerically and they are shown *** is observed that the intensity of the pulses exhibits self steepening which progresses to shock soliton in ultrashort time(or near t=0).Also,it is found that the real part of the solution exhibits self-phase modulation in *** study of(Mi)determines the critical value for the coefficients of SS,SPM,or high dispersivity to occur.

关键词： Perturbed NLSE steepening self–phase modulation extended unified method

Using fracture-based continuum modeling of coupled geomechanical-hydrological processes for numerical simulation of hydraulic fracturing

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1582-1599页

作者： Goodluck i.Ofoegbu GNO Modeling Research LLC. San AntonioTX78253USA

This paper describes numerical simulation of hydraulic fracturing using fracture-based continuum modeling(FBCM)of coupled geomechanical-hydrological processes to evaluate a technique for high-density fracturing and fracture *** simulations are innovative because of modeling discrete fractures explicitly in continuum analysis.A key advantage of FBCM is that fracture initiation and propagation are modeled explicitly without changing the domain grid(*** re-meshing).Further,multiple realizations of a preexisting fracture distribution can be analyzed using the same domain *** simulated hydraulic fracturing technique consists of pressurizing multiple wells simultaneously:initially without permeating fluids into the rock,to seed fractures uniformly and at high density in the wall rock of the wells;followed by fluid injection to propagate the seeded fracture density *** combines the ease of continuum modeling with the potential accuracy of modeling discrete fractures and fracturing *** are modeled as piecewise planar based on intersections with domain elements;fracture geometry stored as continuum properties is used to calculate parameters needed to model individual fractures;and rock behavior is modeled through tensorial aggregation of the behavior of discrete fractures and unfractured *** are presented for previously unfractured rock and for rock with preexisting fractures of horizontal,shallow-dipping,steeply dipping,or vertical *** of a single-well model are used to determine the pattern and spacing for a multiple-well *** results illustrate high-density fracturing and fracture caging through simultaneous fluid injection in multiple wells:for previously unfractured rock or rock with preexisting shallow-dipping or horizontal fractures,and in situ vertical compressive stress greater than *** preexisting fractures are steeply dipping or vertical,and considering the same in situ

关键词： Discrete fracture Fracture-based continuum modeling Fracture caging High-density fracturing Hydraulic fracturing Preexisting fracture

Hardness of Mn_2V_2O_7 thin films and its influential factors

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international Journal of Minerals,Metallurgy and Materials 2015年第9期22卷 987-991页

作者： i. Aft in Kariper Department of Science Education Faculty of Education Erciyes University Kayseri 38039 Turkey

Mn2V2O7 thin films were deposited onto amorphous glass substrates using a chemical bath deposition method and different deposition time. X-ray diffraction （XRD） analysis was used to define the structure of the films. Their roughness, thickness, and surface properties were evaluated through atomic force microscopy （AFM）. The hardness of the films was measured using a nanohardness tester The film thickness, average grain size, and roughness were positively correlated with each other. These three parameters were observed to increase with the deposition time. The film thickness and average grain size were inversely correlated with the hardness and rough- ness. in addition, the number of crystallites per unit area and the dislocation density were observed to be positively correlated with the hardness and roughness. This study was designed to elucidate and formalize the underlying reasons for these relationships.

关键词： manganese vanadate thin films nanohardness influencing factors

Decoding Phthorimaea operculella(Lepidoptera: Gelechiidae) in the new age of change

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Journal of integrative Agriculture 2020年第2期19卷 316-324页

作者： Silvia i.RONDON Hermiston Agricultural Research and Extension Center Crop and Soil ScienceOregon State University

Arthropods and pathogens constantly challenge potato Solanum tuberosum *** of climate variation have increased the possibility of changes in pests’biological and ecological patterns by increasing or reducing overwintering length,changes in population growth rates,number of generations,crop-pest relationship,and therefore affecting their *** operculella Zeller(Lepidoptera:Gelechiidae)is one of the main pests affecting potatoes *** oviposit single or multiple eggs in leaves,stems,and tubers,while the larvae in immature stage mine leaves or burrows into tubers turning them *** control methods are effective in controlling ***,but many factors determine the success of the control *** review provides key highlights of current information available that could be used as a resource to fight this pest.

关键词： climate insects moth potato pest management Solanaceae pest control iPM tubermoth potato tuber moth

Synthesis and Formation Mechanisms of Calcium Ferrite Compounds

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Journal of Materials Science & Technology 2004年第5期20卷 530-534页

作者： Hesham i.Saleh inorganic Chemistry Department National Research CenterDokkiCairoEgypt

Calcium ferrite compounds were prepared using calcium nitrate and iron nitrate with different molar ratios, 1:1, 0.5:1, and 1:0.5, respectively. The reactions of formation were investigated at different temperatures following the differential thermal analysis (DTA) results. Calcium ferrite compounds are CaFeO3, Ca2FeO3.5, Ca2Fe2O5, CaFe2O4, CaFe4O7, Ca7.2Fe0.8Fe30O53, Ca3Fe15O25, Ca4Fe14O25, and Ca4Fe9O17. Other reactive species of calcium nitrate are still present after firing at 450℃. Compounds were characterized using X-ray diffraction (XRD), DTA, TG, magnetic susceptibility, infrared spectra and scanning electron microscope (SEM). it is concluded that the formation mechanism of Ca-ferrite compounds depends mainly on the valency of iron cations which in role depends on its molar ratio and the existing atmosphere.

关键词： Ca-ferrite Formation mechanism Magnetic susceptibility