Schottky Barrier Height Inhomogeneity of Ti／n—GaAs Contact Studied by the I—V—T Technique

The current-voltage characteristics of Ti/n-GaAs Schottky diodes measured over a temperature range of 78-299K have been interpreted on the basis of thermionic emission across an inhomogeneous Schottky contact.The experiment shows that the apparent barrier height (φap) increases from 0.437eV at 78K to 0.698eV at room temperature.the plot of φap versus 1/T does not exhibit a simple linear relationship over the whole temperature range,indicating that the barrier height distribution is more complicated than the frequently observed single Gaussian distribution.A new multi-Gaussian distribution model is developed.Our experimental results can be explained by a double Gaussian distribution of the barrier heights.The weight,the mean barrier height,and the standard deviation of the two Gaussian functions are 0.00001 and 0.99999,0.721 and 0.696,0.069 and 0.012eV,respectively.     

现代中国文化格局的迁动与新文学走向

“五四”时期，深受西方工业文明影响的精英文化、固有的传统农业文明文化与民间文化三足鼎立，共同构成现代中国的新文化格局。精英文化作为主流文化不仅培植了精英文学，而且也左右了新文学的发展流向。20世纪30年代后期，意识形态文化的霸权，改变了既成的文化态势，现实乃至政治的需要促成了新文学主体向民间文化的靠拢，并逐渐奠立了大众文学在新文学中的领导地位。     

Optical Properties of ZnFe2O4—SiO2 Granular Films Prepared by Radio—Frequency Magnetron Sputtering

We report on the optical properties of ZnFe2O4-SiO2 granular films prepared on quartz substrates by the radio-frequency magnetron sputtering method.Post-annealing was performed at different temperatures under flow oxygen atmosphere.The morphology and Structures of ZnFe2O4 nanoparticles were characterized by x-ray different line types in the optical absorption curves of ZnFe2O4-SiO2 granular films.The critical transition of line types occurs when ZnFe2O4 changes from amorphous to crystalline,and the transition temperature increases with the increasing content of ZnFe2O4.There is an obvious blueshift of the optical absorption edge of the granular films with the decreasing annealing temperature.     

Sound Field Calculations of Elliptical Pistons by the Superposition of Two—Dimensional Gaussian Beams

We present an alternative approach to calculate the sound field of ultrasonic transducers.The distribution function of sources is expanded into the superposition of a series of two-dimensional Gaussian functions.The corresponding radiated sound field is expressed as the superposition of these two-dimensional Gaussian beams and is then reduced to the computation of these simple functions.This treatment does not require the condition that the shape of the source is of circular axial symmetry.A numerical example is presented for the uniform elliptical piston transducer and this is in good agreement with the results given by complicated computation.     

Fifth—Order Harmonic Generation using a Coherent Controlled Two—Pulsed Optical Field

We have experimentally studied the characteristics of fifth-order harmonic radiation produced by two coherent femtosecond laser pulses with a changeable relative phase.The intensities of harmonic generation are found to increase with the coherent degree.In one optical Period,the temporal variation of harmonics exhibits an asymmetric characteristic,which is interpreted in terms of ionization theory and the deformation of the wave packets of fundamental field contribution to harmonic generation.     

Modification of Absorption of a Bulk Material by Photonic Crystals

We show theoretically that it is possible to modify absorption of a bulk absorbing material by inserting another non-absorbing dielectric slab periodically to form one-dimensional photonic crystals.It is found that,for frequencies within photonic bandgaps,absorption is always suppressed.For frequencies located at photonic bands,absorption can be suppressed or enhanced,which depends on the relative values of the real refractive index of the absorbing and non-absorbing dielectric layers.     

Fluorescence Microscopy of Nanoscale Silver Oxide Thin Films

The experimental conditions for photoactivated intermittent fluorescence from nanoscale silver oxide were studied with fluorescence microscopy.Strong fluorescence was observed from the Ag2O particles with size of 10-20nm excited with both blue and green light .We observed the saturation of Photoexcitation with blue light and explained the experimental results using the model of agglomeration of silver atoms to form small clusters and the fluorescence of Ag2 and Ag3 clusters.     

在白噪声分析中的广义维里拉普拉斯

一类广义维里拉普拉斯，把在白噪声分析构架中通常定义的维里拉普拉斯作为特殊情形而包含。     

毫微克DNA—DAPI复合物荧光法测定的研究

DAPI（4－6＝脒基－2－苯基吲哚）是检测微量DNA的专一性荧光染料，其最高灵敏度为0．1ng/ml,DNA浓度由微微克向毫微克增大时，峰位红移10－20nm。DNA浓度在1－100ug/ml时，DAPI的适宜浓度范围为30－100ng/ml。