Few projections reconstruction is a difficult problem of image reconstruction. In this paper we propose a modified algorithm based on simultaneous algebraic reconstruction technique (SART), which contains the length of the segment of the ray through the pixel and the value of pixel. The new algorithm solves the edge problem effectively, and makes great improvement of reconstruction precision.

We study the method of using MRA in order to remove noise. From the result of processing for a spot image contadrinated by noise, Signal-Noise Ratio increases greatly, comparing with ideal caset the main characteristic parameters are almostly consistent .The method has a practical value in the problem of removing noise of laser spot's image.

The image boundary detection of the first DEXA in China is presented. From clinical exadrination, it is very succeeded.

A Kinoform based on the Fourier transformation is introduced. By adding quadratic phase factor to the Fourier's Kinoform, we derive a new Fresnel's Kinoform whose object can be reconstructed in the Fresnel difraction field. An improved 2d-FFT algorithm derived from the idea of symmetry is also introduced and some graphics simulated by computer are showed.

The diffuse reflectance and transmittance of rabbit arteries and veins were studied at 496.5 nm wavelength of Ar+ laser and by two standard integrating sphere systems. The ex- perimented data of absorption coefficient, scattering coefficient and the changes of total optical intensities I(x), forward scattering flux i(x), backward scattering flux j(x) as a function of thick- ness of rabbit arteries and veins were evaluated and analyzed by Kubelka-Munk model. The results showed significant difforence of diffuse reffectance and transmittance between arteries and veins, the absorption coefficient of arteries were obviously lesser than that of vein, and the scat- tering coefficient of arteries were obviously bigger than that of veins. The changes of total optical intensities I(x), forward scattering flux i(x), backward scattering flux j(x) versus thickness of rabbit arteries and veins were also significant difference.

The collapses and revivals of atom population are investigated in the two-mode two pho- ton Jaynes-Cummings model, in which Stark shift with a Rotating-Ware Approximation (RWA) and without RWA are all considered. The va1ue of b (b2 = β1/β2, β1 and β2 are the two Stark shift coefficients) thects the perodic time of the collapses and revivals of atom population. Only when b=1, the periodic time is the shortest. Without RWA, we found the atom population exhibits Chaos, which is thected by Stark shift. If β1 equal to β2, the chaos is the weakest. When b deviates from 1, the chaos become stronger.

A scheme is proposed for the generation of superpositions of multi-mode coherent states, i.e. multi-mode Schrodinger cat states. In the scheme a V-type three-level atom is sent through many cavities filled with coherent fields. The whole system is entangled via the Raman atom-field interaction. Then the detection of the atorn leaves the cavity system in a multi-mode cat state. Under certain conditions, such a cat state is identical to a Greenberger-Horne-Zeilinger state and thus can be used to test local realistic theories.

In this paper, a way of secrecy communication with Henon Chaotic system is given, the results of computer simulations show it feasible. The influence factors to chaotic secrecy commnication are also presented.

The high quality crystals of GdAl~~3(BO~~3)~~4:Nd3+ with the sizes of 35mm have been grown from K2Mo3O10-B2O3 solvent system.The a and π polarization absorption and edrission spectra of GdAl3(BO3)4:Nd3+ have been measured. A laser output of 119.5μＪ at 0.532 μm with an optical to optical efficiency of 4.3% was obtained by using self-frequency doubling technology when this crystal was pumped by dye laser. Also, a laser output of 445μJ at 436－443 nm range with an optical to optical efficiency of 7.3% was obtained by using self sum frequency method when this crystal was pumped by dye laser.

In common XeCl excimer laser, using directional prism to replace entire reflection mirror, excimer laser with directional prism cavity was obtained. The laser is high stability of anti-disalignment. Beam distribution is coherent flattened in the near field and focusability in the far field. Directional prism cavity compresses the beam divergence angle, and improves the beam quality This paper provides a novel utility excimer laser technology.

Depending upon the principle of injection locking, using a DFB LD possessed stable mean frequency and narrow linewidth as a mester laser and cooperating a fiber ring laser as a slave one,when the injection locking excited, the linewidth of the master laser is squashed narrower by better resonating characteristic due to long fiber ring cavity. The stable mean frequency and much narrower linewith laser is gained, and its linewidth has been suppressed down to 70 kHz.

In this paper, the integrated optical modulator is realized by integrated optics and optical fiber technologies with 4V driving voltage. The stability and flexibility of front-end shaping system for the ICF solid-state laser driver is greatly improved.

Based upon the solutions of two-dimensional Laplance equations which may be solved with the conformal translation, we has deduced the lateral distribution of injection current in stripe geometry semiconductor lasers. We investigated the variations of lateral distribution of injection current density with different width of the central active regions and different electrode width in the case of low resistivity at resistance layer. If the central active region is thicker than electrode, the injection current density approximates constant in the central active region and quickly declines out the central active region.

The frequency doubling process in crystal has been reconsidered based on the theory of partial coherence in the manuscript the coherence theory concerning the frequency doubling:Ⅰ. definition and description, and the theoretical description of distribution of radiant intensity of the second harmonic wave excited by the incident fundamental wave is finally expressed afresh by the theory of partial coherence. But we may ask whether we might not prove the validity of the result obtained from such abstract idea supplemented by the requirement of demonstrating feasibility of the theory of partial coherence. The author will inquire into the consistency in this contribution between the line of reasoning in the above paper with the former description of the Franken and Ward, and furthermore we see whether the definition and the demonstration based on it are tenable or not.

The effects of focus parameters on the thresho1d, reflectivity of stimu1ated Brilouin- scattering and pulse of Stokes are investigated experimentally.

Raman scattering for doped GaAs/AlGaAs superlattice was measured at T=77 K. Two scattering peaks, whose Raman shift is 223 cm-1 and 422 cm-1, respectively, in Raman spectrum were observed. It is belived that two scattering peaks are related to coupling modes between plasmon and longitudinal optical phonon for Si-doped GaAs/AlGaAs superlattice. Calculated positions of Raman Scattering peaks produced by the coupling modes are in good agreement with measurement results.

This text introduces a set of new-style multi-wavelength solarphotometer contolled by siglechip (SCM). The autocontrol system of this instrument was improved based on the proto- type devoloped by ourself. The new-style photometer is portable and can accornmodate to the abominable environment, miniaturize and improve the ratio of his performance and price. Here are described the necessity of improving solorphotometer, design project, instrument structure, performance index, software design, instrument calibration and its application.

According to the theory of cyclic redundancy Checks, we present the hardware and software methods in Dallas's 1-Wire chips.

In this paper, some problems are discussed about the refraction correction while tracing and measuring the satellite using optical method. First, the magnitude of refraction correction is calculated under different elevation. Then the affect of optical dispersion is discussed. At last, some other problems such as atmospheric turbulence, horizontal asymmetry and the dairy variety of refractive are discussed

The refraction index structure parameters are measured on the surface of Yangbajing, Tibet using high-resolution detector. Results show that the turbulence in this region is very large, although the altitude of Yangbajing over 4300 meters. These phenomena may be attributed to strong solar radiation and special terrain.