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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 81-100页

作者： S.SAURABH R.KiraN d.SINGH R.VAISH V.S.CHAUHAN School of Mechanical and Materials Engineering Indian Institute of Technology Mandi

Bio-inspired helicoidal composite laminates, inspired by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study provides a comprehensive investigation into the nonlinear free vibration and nonlinear bending behavior of bio-inspired composite plates. the inverse hyperbolic shear deformation theory(IHSdt) of plates is employed to characterize the displacement field, with the incorporation of Green-Lagrange nonlinearity. the problem is modeled using the C0finite element method(FEM), and an in-house code is developed in the MAtLAB environment to solve it numerically. Various helicoidal layup configurations including helicoidal recursive(HR), helicoidal exponential(HE), helicoidal semi-circular(HS), linear helicoidal(LH), and Fibonacci helicoidal(FH)with different layup sequences and quasi-isotropic configurations are studied. the model is validated, and parametric studies are conducted. these studies investigate the effects of layup configurations, side-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear vibration and nonlinear bending behaviors of bio-inspired composite plates. the results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behaviors. Moreover, this influence varies across different side-to-thickness ratios and boundary conditions of the bio-inspired composite plate.

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Mechanical and thermal postbuckling of FGM thick circular cylindrical shells reinforced by FGM stiffener system using higher-order shear deformation theory

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Applied Mathematics and Mechanics(English Edition) 2017年第1期38卷 73-98页

作者： d.V.dUNG H.t.tHIEM Faculty of Mathematics Mechanics and InformaticsVietnam National UniversityHanoi 100000Vietnam

the postbuckling of the eccentrically stiffened circular cylindrical shells made of functionally graded materials （FGMs）, subjected to the axial compressive load and external uniform pressure and filled inside by the elastic foundations in the thermal environments, is investigated with an analytical method. the shells are reinforced by FGM stringers and rings. the thermal elements of the shells and stiffeners in the fundamental equations are considered. the equilibrium and nonlinear stability equations in terms of the displacement components for the stiffened shells are derived with the third-order shear deformation theory and Leckhniskii smeared stiffener technique. the closed-form expressions for determining the buckling load and postbuckling load-deflection curves are obtained with the Galerkin method. the effects of the stiffeners, the foundations, the material and dimensional parameters, and the pre-existent axial compressive and thermal load are considered.

关键词： stiffened cylindrical shell functionally graded material (FGM) postbuck- ling elastic foundation analytical

Model with strong γ_4 t-violation

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Chinese Physics C 2008年第12期32卷 939-944页

作者： R. Friedberg t. d. Lee Physics department Columbia University New York NY 10027 U.S.A. China Center of Advanced Science and technology (CCASt/World Lab.) P.O. Box 8730

eAbstract We extend the t violating model of the paper on ＂Hidden symmetry of the CKM and neutrinomapping matrices＂ by assuming its t-violating phases X↑ and X↓ to be large and the same, with X = X↑ = X↓. In this case, the model has 9 real parameters： at, α↑,β↑,ξ↑,η↑t for the t-quark sector, α↓,β↓,ξ↓,η↓, for the sector and a common X- We examine whether these nine parameters are compatible with ten observables： the six quark masses and the four real parameters that characterize the CKM matrix （i.e., the Jarlskog invariant and three Eulerian angles）. We find that this is possible only if the t violating phase X is large, between -120^o to -135^o. In this strong t violating model, the smallness of theJarlskog invariant 3 × 10^-5 ismainly accounted for by the large heavy quark masses, with mc/mt〈ms/mb≈0.02, as well as the near completeoverlap of t and b quark, with （c｜b）=-0.04.

关键词： Jarlskog invariant CKM matrix strong γ4 t-violation

dispersion of Axisymmetric Longitudinal Waves in A Bi-Material Compound Solid Cylinder Made of Viscoelastic Materials

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Computers, Materials & Continua 2016年第2期51卷 105-143页

作者： S.d.Akbarov t.Kocal t.Kepceler department of Mechanical Engineering Yildiz Technical UniversityYildiz Campus34349BesiktasIstanbulTurkey Institute of Mathematics and Mechanics of the National Academy of Sciences of Azerbaijan 37041BakuAzerbaijan department of Marine Engineering Operations Yildiz Campus34349 BesiktasIstanbulTurkey

the paper studies the dispersion of axisymmetric longitudinal waves in the bi-material compound circular cylinder made of linear viscoelastic *** investigations are carried out within the scope of the piecewise homogeneous body model by utilizing the exact equations of linear *** corresponding dispersion equation is derived for an arbitrary type of hereditary operator and the algorithm is developed for its numerical *** numerical results are obtained for the case where the relations of the constituents of the cylinder are described through fractional exponential *** influence of the viscosity of the materials of the compound cylinder on the wave dispersion is studied through the rheological parameters which indicate the characteristic creep time and long-term values of the elastic constants of these *** curves are presented for certain selected dispersive and non-dispersive attenuation cases under various values of the problem parameters and the influence of the aforementioned rheological parameters on these curves is *** a result of the numerical investigations,in particular,it is established that in the case where the rheological parameters of the components of the compound cylinder are the same,the viscosity of the layers’materials causes the axisymmetric wave propagation velocity to decrease.

关键词： Characteristic creep time Viscoelastic material Wave dispersion Bi-material compound solid cylinder Wave attenuation

Challenges in determination of microscopic degree of cleanliness in ultra-clean gear steels

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Journal of Iron and Steel Research International 2022年第10期29卷 1583-1600页

作者： d.Fuchs t.tobie K.Stahl Gear Research Center(FZG) Technical University of Munich85748 GarchingGermany

Shot-peened,case-hardened gears can fail in the tooth root due to crack initiation below the surface of the steel ***,the crack is initiated at a non-metallic inclusion in the center of a so-called *** failure type can lead to a reduced endurance fatigue limit of the *** is for this reason that,over the last decade,much effort has been invested by steel manufacturers to reduce the non-metallic inclusion content of gear steels so as to mitigate or even completely prevent such crack *** ultra-clean gear steels were achieved by various measures in the steel production ***,as a result,the remaining non-metallic inclusions are inhomogeneously distributed in the steel volume in terms of both size and ***,due to the inhomogeneity of ultra-clean steels,the question arose if the values derived according to the standards are still representative of ultra-clean steel *** results show that the standards can still be applied,but more effort must be *** determine the degree of cleanliness,six microsections are currently evaluated according to steel test specification(SEP)1571,method *** is shown that an examination of 24 microsections starting from size class 0 seems beneficial to get more reliable and comparable results of the degree of cleanliness of these ultra-clean gear *** addition,it is shown that a high degree of cleanliness has been achieved for all steel batches investigated with the measures taken in the steel production process.

关键词： degree of cleanliness Non-metallic inclusion Evaluation of inclusion SEP 1571 dIN 50602 Ultrasonic immersion testing Ultra-clean gear steel Gear

Incorporation of europium (Ⅱ) nanostructures into the channels of mesoporous silicon oxy-nitride for enhanced photoluminescence

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Journal of Rare Earths 2018年第5期36卷 449-455页

作者： d. Suresh M. Yamashita t. Akai a National Institute for Advanced Industrial Science and technology （AISt） Kansai Center 1-8-31 Midorigaoka lkeda Osaka 563-8577 Japan 6 Department of Chemistry School of Chemical and Biotechnology SASTRA Deemed University Thanjavur 613 401 India

divalent europium（Ⅱ）-doped mesoporous silicon oxy-nitride materials, as a novel type of nanoscopic photoluminescent material, are studied in which the optically active luminescent centers are isolated within the pores. Colorless and transparent blue emitting luminous Eu2＋-doped mesoporous silicon oxy-nitride materials were prepared from mesoporous silica via impregnation, nanocasting and nitrogen-assisted carbothermal reduction and nitridation method. the morphology and porosity of the silica remain unchanged during the synthesis process as revealed by SEM images and by nitrogen sorption studies. Photoluminescence studies reveal a strong blue emission band for Eu2＋ centered at 425 nm with a quantum efficiency of 47%. the luminescent intensity is greatly influenced by the amount of co-dopant, AI3＋ ions.

关键词： Blue luminescence divalent europium Mesoporous silicon oxy-nitride Carbothermal reduction and nitridation(CRN) Rare earths

Experimental study on the influence of temperature cycle on low-rank coal permeability

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Science China(technological Sciences) 2020年第6期63卷 1055-1065页

作者： ZOU JunPeng JIAO YuYong RAtHNAWEERA t d WANG Hao Faculty of Engineering China University of GeosciencesWuhan 430074China department of Civil Engineering Monash UniversityMelbourne VIC 3800Australia State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China

the formation temperature is a key factor affecting coalbed methane(CBM)migration in *** the prediction of CBM production and prevention of mine gas disasters require the understanding on the controlling mechanism of temperature on coal *** experimentally examined the evolution of permeability for natural low-rank coal samples under various stresses and cyclic temperature *** permeability and intrinsic permeability decrease significantly when the temperature increases and they only partially recover after the temperature *** permeability loss decreases greatly with the increasing number of temperature *** permeability loss due to the rising temperature and the irreversible permeability loss for a whole temperature cycle decrease prominently with increasing confining *** impacts of swelling/shrinking of coal matrix,roughness of surface,pore compressibility and weakly bound water in coal on temperature sensitivity of coal permeability are investigated.

关键词： low-rank coal permeability temperature cycle temperature sensitivity

Effect of Vanadium Microalloying on the HAZ Microstructure and Properties of Low Carbon Steels

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Journal of Iron and Steel Research International 2011年第S1期18卷 393-403页

作者： Milbourn d Baker t N Vanitec ltd Winterton HouseHigh StreetWesterhamKentTN16 1AQUK Metallurgy and Engineering Materials Group Department of Mechanical EngineeringUniversity of StrathclydeG1 1XNUK

Four Steels,C-Mn-0.05V,C-Mn-0.11V,C-Mn-0.03Nb and C-Mn were subjected to heat treatment to simulate the microstructure of a coarse grained heat affected zone (CGHAZ) and an intercritically reheated coarse grained heat affected zone (ICCGHAZ).this involved reheating to 1350°C,rapid cooling (Δt 8/5 =24s) to room temperature and then reheating to either 750°C or 800°*** toughness of the HAZs was assessed using both Charpy and CtOd *** features were characterised by optical,scanning` and transmission electron *** examinations of the Charpy and CtOd specimens were carried out to understand the micromechanism of fracture under different microstructural and test *** CGHAZ toughness was similar for the steels except that Steel C-Mn-0.05V had a slightly lower Itt compared to the *** toughness deteriorated in the ICCGHAZ for all the steels,again Steel C-Mn-0.05V had a superior toughness compared to the other three steels in both ICCGHAZ *** the level of vanadium to 0.11% caused a decrease in ICCGHAZ *** C-Mn-Nb exhibited a greater degradation of impact toughness after the intercritical *** presence of M-A constituents was the dominant factor in determining the toughness of the *** size and area fraction of the M-A constituents were the smallest in Steel *** vanadium level to 0.11% resulted in a greater area fraction of the M-A constituents,larger average and maximum sizes of M-A particles,and significantly more fields containing the *** addition of 0.031% Nb produced the largest M-A particles and the greatest area fraction for the steels tested.

关键词： vanadium microalloyed steel coarse grained heat affected zone intercritically reheated coarse grained heat affected zone martensite-austenite constitute heat affect zone toughness

Comparison of dietary intakes of Canadian Armed Forces personnel consuming field rations in acute hot, cold, and temperate conditions with standardized infantry

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Military Medical Research 2020年第1期7卷 77-92页

作者： Mavra Ahmed Iva Mandic Wendy Lou Len Goodman ira Jacobs Mary R.L’Abbé department of Nutritional Sciences Faculty of MedicineUniversity of TorontoMedical Science Building1 King's College CircleRoom 5368TorontoOntario M5S 1A8Canada Faculty of Kinesiology and Physical Education University of TorontoToronto M5S 2W6Canada dalla Lana School of Public Health University of TorontoToronto M5T 3M2Canada defence Research and development Canada-toronto Research Centre Toronto M3K 2C9Canada

Background:dietary Reference Intakes are used to guide the energy intake of the Canadian Armed Forces(CAF)field rations provided to military personnel deployed for training or ***,the high energy expenditures likely to occur under harsh environmental/metabolically challenging deployment conditions may not be adequately *** study examined the Ad libitum energy and nutrient intakes of CAF personnel(n=18)consuming field rations in a resting thermoneutral environment and during a day of standardized strenuous infantry activities at varying environmental ***:dietary intake was assessed using a measured food intake/food waste method during the experimental treatment and for 6 h after *** treatments were administered in a randomized counterbalanced design:exercise(as standardized infantry activities)in the heat(30℃),exercise in the cold(–10℃),exercise in temperate thermoneutral(21℃)air temperatures and a resting(sedentary)trial(21℃).Results:the average Ad libitum consumption of field rations was 70%of the provided total energy(2776±99 kcal/8 h)during all *** with an acute challenge of increased energy expenditure and temperature stress in the simulated field conditions,participants’energy intakes(1985±747 kcal/8 h)under hot,cold and temperate treatments did not differ from energy intake during the sedentary condition(1920±640 kcal/8 h).participants’energy intakes(1009±527 kcal/6 h)did not increase during the 6 h posttreatment period when the stresses of the strenuous physical activities and the harsh environmental temperatures had ***:these results should be considered when planning the provision of field rations for CAF personnel expected to be engaged in strenuous physical activities with prolonged exposure to temperature extremes.

关键词： dietary assessment Nutrient intakes Military personnel Physical activity temperature extremes Field rations

Sensing thermal Underground transients of Buried Wired Structures

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Journal of Earth Science and Engineering 2013年第11期3卷 730-743页

作者： ira Kohlberg William Szymczak Camille d'Annunzio Kohlberg Associates lnc 11308 South Shore Road Reston VA 20190 USA Naval Research Laboratory Physical Acoustics Branch 4555 Overlook Ave SW Washington DC 20375 USA Northrop Grumman ES Automated Sensor Exploitation Technology Center 1550 W. Nursery Road Linthicum MD 21090 USA

Mathematical investigations of the dynamic response of buried systems to thermal and/or electromagnetic stimulation continues to be of great importance. the size of such systems can range from the microelectronic scale to large underground structures. Stimulation can occur from unwanted electromagnetic signals entering the buried system, and for assessing the operating state of a buried system that is not usually physically accessible. In both cases detecting damage or status can be accomplished by examining the time dependence of the resultant surface temperature. this study shows how to determine surface temperature for a hypothetical thermal-plus-systems using a combination of Fourier-space and Laplace-time transform techniques. the hypothetical model can be generalized from scaling the relevant relationships.

关键词： Electromagnetic heating buried wire surface temperature Laplace transform.