Abstract:A detailed theoretical analysis of the electrostatic electron cyclotron resonance maser is given, in which the radial thickness of electron beam, ac and de space charge effects are taken into consideration. The characteristic changes of EECRM are also discussed in this paper.

Abstract:The gain and efficiency of Cherenkov EEL are studied. The results show that under the conditions of suitable physical parameters and matching operating phase, the gain and efficiency of Cherenkov FEL are considerably higher than those of common free electron lasers.

Abstract:The exciton levels in ZnSe/ZnS superlattice is studied theoretically and experimentally for the first time. The energy levels of electrons, holes and excitens in the superlattice as a function of barrier width are calculated with LCAO theory and Kronig-Penney model. The absorption and photoluminescence spectra of a sample with a barrier width of 5.8nm are measured at 77K. The experiment results are in good agreement with the theoretical calculations.

Abstract:在2.5～25μm范围内测量了分子束外延(MBE)Pb_(1-x)Eu_xTe薄膜材料(x=0,0.011,0.032,0.045)的室温红外透射谱,得到了折射率的色散关系及禁带宽度与组份x的关系,首次报道了禁带宽度与光学介电常数的经验公式,讨论了本文结果与其它报道的不同之处。

Abstract:Photoreflectance (PR) lineshapo of quantum wells is discussed simply. The MBE GaAs_(1-x)Sb_x/GaAs hotorostructures and strained layer multiple quantum wells have been investigated by means of PR measurement. The advantages of the photoreflectance spectroscopy in the study of MBE epitaxial film are found in this paper.

Abstract:用傅里叶红外吸收谱对不同热处理条件下的SOI样品进行了系统的分析,结果表明:对于190keV,1.8×10~(18)/cm~2N~+注入的样品,在低于1100℃的温度下退火可保持氮化硅埋层的无定形态,而～1200℃热退火则导致氮化硅埋层的结晶成核现象。对于200keV,1.8×10~(18)/cm~2O~+注入的样品,氧化硅埋层的形成是连续渐变的,注入的氧化硅埋层向常规的热氧化非晶态SiO_2转变的激活能为0.13eV。

Abstract:通过对α-Fe_2O_3球状和园柱状超细微粒的红外透射光谱测量,发现形状不同导致表面声子吸收的明显差异,并对实验结果进行了讨论和分析。

Abstract:分析了大气中CO_2浓度增加对太阳辐射和地球长波辐射的影响,并提出了从卫星上监测CO_2增加对辐射传输影响的方法。

Abstract:Considering the heat convection in a wind field, the infrared radiation statistics of natural terrain is analyzed by the heat balance equation. The first-order approximation is used for the radiation term in the equation. The results show that the heat convection will change the statistical distribution of the radiance in the thermal image of natural terrain. With the increase of wind speed, the most probable and average temperature will trend to the steady air temperature, and the contrast of the thermal image will decrease. The saturation phenomena of the convection effect are pointed out.

Abstract:The conditions and factors which determine and affect the temporature peak in the materials during infrared heating are discussed. The temperature fields in dry materials with constant thermal properties during infrared heating are calculated bynumerical method with a transient one-dimensional combined radiative-conductive heat transfer model. The results show that the radiation is the main factor to cause the temperature peak, and the essential conditions for the existence of the temporature peak are the following: (a) there is irradiation on the surface; (b) the transmissivity of the surface is not equal to zero; (c)the material is semi-transparent; (d)the heated surface is cooled by convective heat transfor. The effects of absorption coefficient, refractive index, heat conductivity, convective heat-transfer coefficient and radiative properties of the surf ace on the temperature field are discussed too.

Abstract:It has been found from our previous studies that there is no Landau damping in N-type doped narrow-gap HgCdTe, which is contrary to the existing theory and experimental fact. The further study on the effect of doping and hence the degeneration on the dispersion relation of energy of free-carriers and the calculation of Lindhard function of free-carriers taking into account this effect show that the absence of Landau damping results from the change of free-carrier behavior caused by the dispersion relation of energy of free-carriers.