The fabrication of HEMT of AlGaN/GaN heterostructures grown on sapphire substrate is reported. Without any heat dissipation equipments,gate-length 0.3μm and gate-width 100μm devices exhibit excellent DC characteristics,saturated current is 55.9mA,maximal current is 92.1mA.
The photochemical quenching value of C_3 and C_4 plants differs little, while the none photochemical quenching of C_4 plant was 36%~67% higher than that of C_3 plant, it has a good heat dissipation.
At the same time, Fv/Fm, Fv/Fo, Fv′/Fm′ increased along with the osmotic potential lower than -4 bar; nevertheless ΦPSⅡ, electron transfer rate (ETR), photochemical efficiency, heat dissipation and heat dissipation rate decreased.
However, the mean values of F_v/F_m, F_v/F_o, Ф_ PSⅡ, F′_v/F′_m and photochemical quenching coefficient (q_p) were higher in Rosaceae species than those in Magnoliaceae species, indicating that PSⅡ of the formers had higher capacity of heat dissipation and could prevent photosynthetic apparatus from damage by excessive light energy.
The calculations are based on the equation of current motion with temperature and field-dependent critical current density, and the heat dissipation produced by flux motion in the normal state region and the superconducting state region.
While the wind velocity and the temperature of heat sink base remain the same, the heat dissipation per square centimeter of the composite heat sink is almost the same as that of staggered pin fin heat sink, and 10%~17% higher than that of the platefin heat sink.
The agreement between the momentum and heat dissipation rates calculated directly from the w spectrum(the turbulence spectral method)and indirectly from equations(15)(16)are quite good.
The cutting heat dissipation in chips, workpiece, tool and surroundings during the high-speed machining of carbon steel is quantitatively investigated based on the calorimetric method.
Based on these results, the authors recommended a minimum complex of physiological criteria for regulating the duration of work with preset intensity under conditions of impeded heat dissipation.