TEMPERATURE DEPENDENT DEVELOPMENT OF ASIAN CORN BORER Ostrinia furnacalis

Temperature dependent development in the Asian corn borer, Ostrinia furnacalis (Guenee) was determined at nine constant temperatures between 10℃ and 34℃. Except for 10℃ development of all life stages occurred at the temperatures tested, however, mortality was significantly great at the extreme temperatures(12℃ and 34℃). Egg, larvae and pupae duration accounted for 17%, 57% and 25% of total one of immature stage, respectively Lower developmental thresholds estimated to be 10 38, 10 06 and 11 07℃ for eggs, larvae and pupae, respectively. Upper limited thresholds were 28 00, 31 00 and 31 00℃ for eggs, larvae and pupae, respectively. The heat unit requirements for egg stage were 79 15 degree days, for larval stage were 339 73 degree days, and for pupal stage were 128 82 degree days, respectively. Overall, heat unit requirements for development from egg to adult were 539 91 degree days between lower developmental threshold 10 35℃ and upper limited threshold 32℃.

对电动机的保护的探讨

由电动机的故障原因出发，应用电机发热理论，通过对电动机的电磁故障的分析探讨。

Numerical investigation of temperature gradient-induced thermal stress for steel–concrete composite bridge deck in suspension bridges

A3D finite element model(FEM)with realistic field measurements of temperature distributions is proposed to investigate the thermal stress variation in the steel–concrete composite bridge deck system.First,a brief literaturereview indicates that traditional thermal stress calculation in suspension bridges is based on the2D plane structure with simplified temperature profiles on bridges.Thus,a3D FEM is proposed for accurate stress analysis.The focus is on the incorporation of full field arbitrary temperature profile for the stress analysis.Following this,the effect of realistic temperature distribution on the structure is investigated in detail and an example using field measurements of Aizhai Bridge is integrated with the proposed3D FEM model.Parametric studies are used to illustrate the effect of different parameters on the thermal stress distribution in the bridge structure.Next,the discussion and comparison of the proposed methodology and simplified calculation method in the standard is given.The calculation difference and their potential impact on the structure are shown in detail.Finally,some conclusions and recommendations for future bridge analysis and design are given based on the proposed study.

The study of temperature effects on steel box girder for Taizhou Bridge

Using the temperature gradient which was proposed by continuously measuring flat steel box girder of Runyang Bridge, temperature effects of flat steel box girder were studied for Taizhou Bridge. With three temperature gradient models （JTG D60--2004 specification, BS5400 specification and the temperature gradient which was proposed in this paper）, the stress of control sections was calculated by finite element program ANSYS. The calculated result indicated that the temperature gradient that was put forward in JTG D60-2004 specification and BS5400 specification for calculating the stress of fiat steel box girder was not suitable to apply to fiat steel box girder. The temperature gradient on flat steel box girder which was proposed in this paper was reasonable.

Shear Viscosity of Hot QED at Finite Chemical Potential from Kubo Formula

Within the framework of finite temperature field theory this paper discusses the shear viscosity of hot QED plasma through Kubo formula at one-loop skeleton diagram level with a finite chemical potential The effective widths (damping rates) are introduced to regulate the pinch singularities and then gives a reliable estimation of the shear viscous coefficient.The finite chemical potential contributes positively compared to the pure temperature case. The result agrees with that from the kinetics theory qualitatively.

Influence of Quantal and Statistical Fluctuations on Phase Transitions in Finite Nuclei

Investigations on thermal evolution of pairing-phase transition and shape-phase transition in light nuclei are made as a function of pair gap, deformation, temperature and angular momentum using a finite temperature statistical approach with main emphasis to fluctuations. The occurrence of a peak structure in the specific heat predicted as signals of the pairing-phase and shape-phase transitions are reviewed and it is found that they are not actually true phase transitions and it is only an artifact of the mean field models. Since quantal number and spin fluctuations and statistical fluctuations in pair gap, deformation degrees of freedom and energy when incorporated, it wash out the pairing-phase transition and smooth out the shape-phase transition. Phase transitions due to collapse of pair gap and deformation is discussed and a clear picture of pairing-phase transition in light nuclei is presented in which pairing transition is reconciled.

Research on temperature rise of hoisting machine disk brake

A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes during emergent brake course was analyzed and calculated by using finite element software. By analyzing the calculation results, the law of tempera- ture change of surface of brake disk and shoes during the braking process was found. The law of brake shoes surface tempera- ture distribution and the law of temperature change along with thickness of brake shoes at brake time 0.5 s, 1.0 s and 1.5 s was analyzed. A hoisting machine emergent braking test was carried out. Finally, the author concluded that velocity rebound in the process of hoisting machine emergent brake is due to decreased friction coefficient caused by the temperature rise of the brake shoes surface.

SIMULATION AND OPTIMIZATION FOR THERMAL SYSTEM IN GROUND ARTIFICIAL FREEZING

The situation of mine development in coal industry of China and the method of shaft freezing in the type of double ring freezing pipe used for shaft sinking under thick alluvium condition are briefly reviewed. The equations of heat conduction are numerically solved for two kinds of artificial shaft freezing-sin-gle and double ring freezing pipe pattern. A two-dimensional finite difference model simulating the temperature field is developed. The paper introduces a way to calculate the harmonic mean of heat conductivety used when dealing with heterogeneous material, The theoretically derived temperature distributions in frozen soil are given and the comparison is made between two types of freezing pipe arrangement. The optimization technique of a general simulation is discussed, and that is in use to improve the thermal system in shaft freezing.

Effect of cooling structure on thermal behavior of copper plates of slab continuous casting mold

A three-dimensional finite-element model of slab continuous casting mold was conducted to clarify the effect of cooling structure on thermal behavior of copper plates. The results show that temperature distribution of hot surface is mainly governed by cooling structure and heat-transfer conditions. For hot surface centricity, maximum surface temperature promotions are 30 ℃and 15 ℃ with thickness increments of copper plates of 5 mm and nickel layers of 1 ram, respectively. The surface temperature without nickel layers is depressed by 10 ℃ when the depth increment of water slots is 2 mm and that with nickel layers adjacent to and away from mold outlet is depressed by 7℃ and 5 ℃, respectively. The specific trend of temperature distribution of transverse sections of copper plates is nearly free of cooling structure, but temperature is changed and its law is similar to the corresponding surface temperature.

Coulomb Screening and Plasmon Excitation in Graphene at Finite Temperature

By using the random phase approximation (RPA) in many-body perturbation theory,we calculate thepolarization function of the electron gas in graphene at finite temperature.Based on this,we calculate the temperaturedependent dielectric function ∈(q).The thermal effect on ∈(q) in various q regions is discussed.The temperaturedependence is found to be quadratic.We also investigate the plasmon dispersion relation at finite temperature,with thezero-temperature relation as a special case.The result is in good agreement with recent experimental data.

Dispersion Theory of Polaron in a Parabolic Quantum Dot at Finite Temperatures

By using the dispersion theory instead of the Frohlich Hamiltonian, the polaron energy in a quantum aot with a parabolic confinement potential is investigated at finite temperatures. It is found that the self-trapping energy of the polaron decreases with the increasing temperature, and the temperature effect is more obvious in quantum dots with weaker confinement.

A continuum thermal stress theory for crystals based on interatomic potentials

This paper presents a new continuum thermal stress theory for crystals based on interatomic potentials.The effect of finite temperature is taken into account via a harmonic model.An EAM potential for copper is adopted in this paper and verified by computing the effect of the temperature on the specific heat,coefficient of thermal expansion and lattice constant.Then we calculate the elastic constants of copper at finite temperature.The calculation results are in good agreement with experimental data.The thermal stress theory is applied to an anisotropic crystal graphite,in which the Brenner potential is employed.Temperature dependence of the thermodynamic properties,lattice constants and thermal strains for graphite is calculated.The calculation results are also in good agreement with experimental data.

Study on fire extinguishing performance of ultrafine water mist in a cup burner

Two simplified models for predicting minimum extinguishing concentration(MEC) of ultrafine water mist(UFM)(<10 m) were developed based on limiting oxygen concentration(LOC) and combustion limit temperature(CLT),respectively.Experiment was conducted using a modified cup burner which can reduce the surface adsorption of UFM.Two typical liquid fuels,n-heptane and ethanol,were used in the experiment.Tests using the same scenario were repeated 20 times or 10 times according to the variance of extinguishing time.The average and the standard deviations of extinguishing time were used to evaluate the fire extinguishing performance of UFM.Experimental results agree well with the model based on LOC,and disagree with the model based on CLT.The disagreements were explained by analyzing flow behavior of UFM.It was concluded that the primary mechanism of fire extinguishment with UFM was oxygen dilution.

Two-dimensional Modeling of a Salt-gradient Solar Pond with Wall Shading Effect and Thermo-physical Properties Dependent on Temperature and Concentration

In this paper,the behavior of a salt-gradient solar pond with the square cross-section has been studied experimentally and numerically.A small-scale solar pond were designed and built to provide quantitative data.A two-dimensional,transient heat and mass transfer model has been solved numerically by using finite-control-volume method.In this study,all the thermo-physical properties are variable as the function of temperature and salt concentration.Numerical results as obtained for the experimental pond have been satisfactorily compared and validated against measured data.Furthermore,the wall shading effect has been elaborated to improve the agreement between two sets of results.The temperature of the storage zone is predicted well by the model.It also can be observed that the initial concentration profile is preserved with time.The stability of the pond in time has been investigated in order to distinguish the critical zones.Finally,the application of an energy analysis gives an efficiency of about 12%for the pond.

Mechanism study of the transmission of moxibustion heat in human acupoint tissues

Objective: To discuss the topical action characteristics of the biological transmission of moxibustion heat via temperature collection and numerical modeling. Methods: Temperature of moxibustion was measured at multiple points at a distance of 3 cm to obtain the moxibustion temperature field nephograms by the high-accuracy temperature measure array. Finite element analysis was used to imitate the three-dimensional dynamic distribution of temperature in acupoint tissues. Results: Through numerical analysis, the one-dimensional, two-dimensional and three-dimensional distributions of temperature in human acupoint tissues at 5 min of moxibustion were established. The result showed that moxibustion heat mainly tran smitted from the surface of the tissue to the internal, and the in flue nee of moxibusti on heat decreased with the depth of the tissue. The analysis of the nephograms of acupoint tissue temperature at 5,10, 15 and 20 min of moxibustion showed that with the in crease of the moxibusti on time, the temperature in acupoint tissues consta ntly rose, and the transmission depth of moxibustion heat also further expanded inside acupoint. Conclusion: By establishing the three-dimensional dynamic model of heat transmission inside acupoint tissues with the biological parameters of human tissues and the temperature values obtained, this study used finite element analysis software ANSYS 14.0 and discovered the rules in the transmission of heat in body tissues during moxibustion, and the features in moxibustion heat transmission (from the proximal to the distant) and heat penetration (from the surface to the intern al). This study provides theoretical and experime ntal support for the application of moxibusti on in clinical practice.

Vector Meson Mass in Finite Density and Temperature Lattice QCD

Vector meson mass values are studied at finite chemical potential and temperature in lattice QCD with lattice size of 24 × 122× 6 using two flavors of staggered quarks. The investigation focuses on the change of the vector meson mass in the critical region close to T c with two different types of chemical potentials switched on: the isoscalar chemical potential μS and its isovector counterpart μV. It is found that the vector meson mass increases in the QGP phase with both chemical potentials and decreases with μS in the confinement phase.