This paper reviews worldwide research progress of pulsar timing observation, and discusses mainly the views for millisecond pulsar timing develop in China, as well as gives the results of time scale research by using wavelet decomposition method. It is pondered on some problems of high precision timing for future. Some engineering problems for pulsar timing and its application research to be carried out with international cooperation are also suggested in this paper.

In this pager, the self-phase modulation effect in gain saturated semiconductor optical amplifier and its affect on the shape, phase and spectrum of transmission pulse are analyzed. We also point out that the dispersion of transmission fiber can be compensated for with this effect. But in order to acquire an optimum dispersion compensation, the disposal of system and the structure parameters of amplifier must be chosen carefully.

In this paper, the modulated characteristics of CdTe electroptic Q-switched crystal and FM crystal are analyzed and Q-switched RF excited waveguide CO2 laser tuned by grating using CdTe electroptic FM crystal is present. The Q-switched pulse repetition rate is 1 Hz~10 kHz. The peak power of 300 W and the pulse width of 150 ns have been obtained at the pulse repetition rate of 10 kHz.

In this paper, the attenuation spectrum, absorption spectrum and emission spectrum of polymer optical fiber were measured by CCD spectrometer and the other precise spectrometer according to the demanded precision, and their properties were analyzed. Some phenomenons, such as the Raman spectrum effecting on the fluorescence, were discussed.

In this article, the excellent single crystal Nd:GdVO4 with dimension of 30 mmx40 mm has been grown and its transmission spectrum has been studied. The absorption coefficient of Nd:GdVO4 at 809 nm is 4.61cm-1. In 200~342 nm , Nd:GdVO4 has strong host absorption and its absorption edge lies in 342 nm . In 342~2500 nm, the absorption of Nd:GdVO4 is mainly from the characteristic absorption of Nd3+.

A new classification technology is proposed in the paper. It abandons defects of traditional linear local search, introducing jumping search. It can jump out the trap of the local better solution and find the best solution. The article relates its principles detailedly. And using the jumping search of simulated annealing, we have done algorithm training. Experimental results show that this method is more effective than local search on identification and classfication of gas's infrared remote sensing data.

The absorption and transport scattering coefficients of biological tissues determine the radial dependence of the diffuse reflectance that is due to a point source. In order to noninvasively determinate the optical scattering and absorption coefficients of biological tissue, we must know the radial dependence of the diffuse reflectance. There are several different solutions of the diffusion equation for steady-state spatially resolved reflectance for different approximation and boundary conditions at the turbid-medium-air interface. To determine which solution is more accuracy, we compared these solutions with Monte Carlo simulations and fitted the solution data with Monte Carlo simulation results. The accuracy of the different solutions are given, which are useful for noninvasive determination of the optical scattering and absorption coefficients of biological tissue.

The paper systematically studies and analyses the therapeutical principle and therapeutical method of powerful laser cosmetology and low-intensity laser cosmetology. The paper puts forward the therapeutical law to elect parameters of laser according to the state of an illness and to treat the illness both outside and inside the body. The paper provides a reference for clinical application of laser in cosmetology.

The solution of non-linear Schrodiuger (NLS) equation including twophoton absorption in optical fibers, is given by using travelling wave method, and the solution for the propagation characterstics of dark soliton is also discussed in detail.

We derive the state vector of a cascade three-level atom interacting with non-correlation coherence states in a Kerr-like medium. It is shown by numerical calculations that the Kerr effect results in the adiabatic transition transfer phenomenon of electrons just like the case of the correlation field interacting with an atom, but some new properties exist.

In this paper we give a way of chaos communication with CKS. At the sending-end, signal was modulated by 2PKS, and at the receving-end, the signal was demodulated by its own delay. We simulated this way of chaos communication by computer, with logistic chaotic system, Henon chaotic system and Lorenz chaotic system, and proved it is feasible.

In this paper, the antibunching effect of two coupling atoms interacting with a single mode light field in a Kerr medium is studied by means of the quantum theory. The influences of the Kerr medium on the degree of second order coherence is also discussed. The relations between the excited field intensity, the coupling constants of two atoms and the degree of second order coherence are revealed.

On the basis of reference [3], the paper probes the squeezing effects of unequal-power higher-power H-squeezing in the second king of multimode superposition state light field with the superposition of two quantum state by using the definition of multimode squeezing. It is found that when the sum of the squeezing power of each mode is even number, the state is always in Nj- H minimum uncertainty state;when the sum of the squeezing powers of eachmode is odd number, under some certain conditions the state , can also present Nj-th power H-squeezing that changes periodically;the result of reference [3] is only a particular example under the certain condition Nj = N of this paper's universal result.

The amplifier model with XPM effect is given. The XPM has an effec on the small-signal gain. The deviation caused by XPM effect in EDFA is stronger with the increasing of nonlinear coefficient, pump power and amplifier length. Simulation results prove: to neglect the XPM originating in the EDFA is inaccurate. This is particularly true when its higher coefficient of nonlinearity is taken into account, even in r >0.01/W.m, XPM in the first EDFA of a cascade EDFA can't be negnected.

The impact of crosstalk in an arrayed-waveguide (AWG) on an optical add-drop mul-tiplexer(OADM) is investigated. The OADM constitutes of m add/drop channels and n-pass channels. Theoretical analysis shows that the singal-to-noise ratio QCT of the OADM increases as either N or m is nonlinear degraded. Number of channels in a network based on OADM's is limited by crosstalk in the AWG router.

A new applicable fiber optic sensor for monitoring density of methane in air is reported, in which the dual-wavelength and differential absorption method are used. In the sensing system, low-loss optic fiber is applied as transmit loop, and 1/4 period gradient index rods are used as collimating lens. The sensing length of the system is 3 km.

Optical storage based on photoinduced birefringence in azobenzene side-chain polymer liquid crystal (P-CN) film is reported . Measurements show that the P-CN film possesses large photoinduced birefringence ( n ~ 10-2) and good optical storage characteristics.

An organic light-emitting diode based on heterojunction consists of hole-type polymer PDDOPV [poly (2,5-bis (dodecyloxy)-phenylenevinylene)] and electron-type PPQ [poly (phenyl quinoxaline)] is successfully fabricated. The highest brightness of the heterojunction device is 106 times of the lowest brightness of its own, 365 times of that of single layer device of PDDOPV. The highest luminescent efficiency is 336 times of that of single layer device of PDDOPV. The heterojunction devices can be operated at forward bias voltage, reverse bias voltage and ac (alternating current) voltage. Emission at forward bias voltage and ac voltage are from PDDOPV, but emission at reverse bias voltage includes not only emission from PDDOPV but also emission from PPQ. The reason of the capability of heterojunction device can be operated at reverse bias voltage is that enough high electric field leads to the tilt of energy band, then the tilt of energy band makes the injection barrier thin enough to be injected by carriers through tunnel.

It is important to find a precise and fast algorithm for solar radiative transfer in the atmosphere . In this paper, we present, based on Stamnes's discrete-ordinate-method, an analytical four-stream approximation algorithm. In our algorithm, we separate out the singly scattered radiation and apply the normal four-stream approximation of Stamnes's discrete-ordinate-method to the multiply scattered radiation alone. The singly scattered irradiance is computed analytically without approximation, preserving more of the angular dependence in the radiance than other four-stream approximation solutions. Because of the analytical form of the derived solution, the computational time of our algorithm is less than that of the rigorous numerical algorithm. Numerical experiments show that the accuracy of the algorithm is satisfactory. Particularly in the case the absorption is dominant, the error of the algorithm is very small.

This article is based on a experimental polarization CCD camera. In the sunlight, we obtain some polarization images of natural objects and manmade objects. As a result, compared with intensity images, low illuminance (shadow etc.), esperially information of edge is enhanced. The experimental results show that it is useful to detect texture by polarization information. Combined with the enhancement of edges' information , polarization detecting has wide application in military detecting and camouflage recogonision.

The imaginary hot stimuli and Real hot Studied by fMRI. The similarity and difference of the brain's excitation have been found. The brain's area SI, left superior frontal gyrus, left middle frontal gyrus, motor area of cerebrum and cingulate gyrus have been excited by imaginary hot stimuli. And the brain's area SI, right superior frontal gyrus, right middle frontal gyrus and motor area o cerebrum have been exctited by real hot stimuli. The excitation of frontal lobe and cingulate gyrus are different between the two situations. These results are almost the same as the excitation by imaginary and real cold stimuli except the excitation of the frontal lobe.