The laser hardening technology used for crankshaft is introduced and the investigation on surface hardening of a nodular iron crankshaft was carried out by using a kW CO 2 laser system.By building the temperature field mold,we explained the phenomenon that the laser hardening depth is not dispersed averagely along the direction of laser movement on laser hardening crankshaft neck . By this temperature field mold we can optimize technical parameters of laser hardening on computer directly instead of by conditional methods. Theoretical calculation is consistent with the experiment.

Surface hardening of drill-stem joint material 30CrMnSiA by using 2kW power and 100mm/min scanning velocity has been performed, The microstructure and wear resistance of the transformation layer have been studied ,The experimental results show that the surface hardened layer consists of the hardened region and the interim region and the temper microstructure,The microstructure of hardened layer was very tiny,Its wear resistance higher than the 30CrMnSiA steel in the normal state

In this paper, the formability of cold rolled steels after laser welding were analyzed. Cupping test show that the difference of thickness of welded blanks can lead to the reduction of IE to a large extent while LDH and Hole Expansion test indicate that the formability of welded blanks reduced with the increase of difference of thickness and strength. FLD of welded blanks also displayed that the formability of cold rolled blanks after laser welding dropped compared with those of the base metal. The location of forming for laser welded blanks should avoid from the complex situation of forming for auto parts.

By using the matrix theory of the laser resonators, the G parameters of plane-plane cavity and the condition of themal thick len inside laser resonators are given. The optimistic design of laser resonator is made to obtain by using the graphic method Then the experiments are carried out with the designed resonators parameters.When input electric power is 450W, its output laser power is up to 50W, The electro-optic efficiency is 11.1% and the light to light conversion efficiency is up to 30%. The power stability is ±2 %。

Study on laser alloying of Si3N4/graphite composite coating on 45carbon steel has been carried out in this paper. The microstructure, micro-hardness, contents and distributions of elements and tribological performance of coatings have been analyzed and studied. Based on these analyses, the ingredients and proportion of powders in pre-coatings and parameters of laser alloying are optimized. The results show that laser alloying of Si3N4/ graphite can attain high quality coating with uniform microstructure and increased hardness. And the alloyed coatings have lower friction coefficient, higher wear resistance, stronger anti-cohesion and steady tribological process under dry friction condition.

Zn/ZnO nanoparticles were prepared by Laser heating gas-evaporation method in this paper, with a 150W CW CO2 laser as light source and Zinc as a target. The effects of process parameters on nanoparticles have been pilot studied. XRD, ED, TEM and EDTA Complexo- metrictitration, were used to characterize the samples. The experimental results showed that the process parameters such as reaction pressure, the sort and rate of airflow affected the sizes and crystal system of nanoparticles. The products were varied with reaction atmospheres. It was also discovered that Zn and ZnO nanoparticles' diameters were between 35nm and 120 nm in inert gases. While pure acicular ZnO nanoparticles, 75nm in length, and 10nm in width were acquired in the oxygen, and Zn nanoparticles were obtained in the hydrogen, whose diameters were about 23nm. This method is expected to have the possibility of wide applications in the industry in the future.

TEA CO2 laser beam was used to irradiate the mixed crystal of NiSO4 and Ni(Ac) 2 , which had been grained into powders of 2μm size and then pressed into pieces of 10 mm diameter as target material. Nanoparticles of NiSO4/Ni(Ac)2 , containing a little Ni2O3 , were prepared. The size of which was 10 to 20 nm. And the gas products were H 2O and CH 3COOH. The laser power density was of 108 W.cm-2 order of magnitude. The mechanism of laser action is discussed. A method of laser ablation for preparing nanoparticles, the chemical composition of which is as similar to that of the target material as possible, is being offered.

Starting from Mie scattering theory the scattering and extinction characteristics of sand-dust particle on visible light have been studied by numerical method. Influence of the extinction effect on atmospheric visibility has been discussed. It is found that the scattering and extinction effect of sand storm on visible light especially red light is substantial. Sand storm has a bad effect on urban traffics.

The method of scanning and receiving with two beams can double the scanning image's pixels without increasing the laser's pulse repetition rate and the scanner's operating frequency, or double the frame frequency while the pixels remain the same. It can also increase the maximum of non-fuzzy distance and depress the requirement for the scanner and the laser. It is in prospect of being applied to laser radar with high frame frequency or high pixels.

In this paper, the temporal characteristics of a distributed feedback R6G dye-doped sol-gel silica laser are investigated theoretically. The numerical solutions of the coupled rate equations predict the variation of the pulse formation and time behavior under different pump intensity. The experimental results show excellent agreement with the computer solutions

The principle of surface plasmon resonance phenomenon and excitation condition of SPR are described in the paper .The relationship between the resonant angle produced by the prism SPW sensor and liquid refractive index as well as dielectric constant is analysed based on the electromagnetic field theory and particle vibration. The SPR depends on the permittivities both the metal and the dielectric medium,and its energy is localized at the interface. So this kind of senor has high sensitivity to changes in the refractive index and configuration of the surface. Surface plasmons are excited at a specific incident angle and result in a massive reduction in reflectivity at that angle required for excitation. Changing in the interfacial refractive index results in a change of the optimal angle required for excitation .Using a prism SPW sensor testing system ,measure the relationship between different concentration from 0% to 70% glycerine solution refractive index and resonant angle. Experimental results obtained ha

It is pointed out that the conclusion in the reference [1] is not correct. The formula for Fraunhofer diffraction, which describes the diffraction pattern on an observing screen locating at the divergence center of an illuminating spherical wave and being parallel with the diffracting screen, is deduced from the Rayleigh-Sommerfeld formula of the scalar diffraction theory. The application condition of the formula is also discussed. Applying the formula to the particles scattered randomly over a 2-D plate, the light intensity formula and the measurement formula for a particle diameter, which describe the Fraunhofer diffraction pattern of the particles, are derived. The authors demonstrated that, when the Fraunhofer diffraction method is used to measure the average dimension of the particles, it is necessary to adopt the formula for the case of a big diffraction angle, the related correct result can be obtained. There is not any systematic error mentioned in reference [1] that increases with the value of diffractionangle.On the contrary,under the condition that the diffracting distance doesn't change,the measurement accuracy increases and the accidental error decreases as the diffraction abgle increases.

This paper introduces the new device to measuring the width, describes its stracture and workprocess.

Based on the theory of computer~~generated hologram, small variation method has been proposed for computing the distanse between the object point and the position on hologram taken Fresnel's point light CGH as example. So the fast algorithm for Fresnel hologram has been offered. This laies the foundation of fast computating way for an actual object's hologram.

In this paper, a new method of using high brightness and high purity LED to restore the hologram is presented, which has the features of practical, convenient, simple, economical and good performance. Spectral characteristic of different color LED is also compared. The production of the LED, which has adjustable constant currant power supply is introduced too.

We researched how to treat superficial disease or intracavitary disease through endoscopy by Ho:YAG laser based on its biological effect.The relative items such as indications、safe and effective doses、methods、curative effects、attention proceedings about Ho:YAG laser treatment were discussed and summarized.

Objective:The effects of He-Ne Laser Irradiation on peripheral blood serum IgG in Mice were studied,in order to illustrate mechanism of the immune modulation effect of He-Ne laser irradiation with the concentration changes of peripheral blood serum IgG in mice. Methods:By irradiating upon the inner corners of the mice eyes with He-Ne laser at five different dosages of 7.33, 11.00, 14.67,22.00 and 36.67J/cm 2 for eight days,the concentration of peripheral blood serum IgG were monitored kinetically at the 3rd, 6th, 9th, 13th and 17th day after laser irradiation. Results:The values of peripheral blood serum IgG increased in some degree at the 3rd,6th and 9th day in the groups of 7.33,11.00, 14.67 and 22.00J/cm 2, while the values decreased significantly in the group of 36.67J/cm 2. Conclusion:He-Ne laser with the proper dosages showed the up regulation effects on the concentration of peripheral blood serum IgG in mouse;while the large dose showed the down regulation effects.

Kunming mice were divided into three groups: control group(A),He-Ne laser irradiation for 10min group(B), He-Ne laser irradiation for 20min group(C). The results is that SOD and MDA of C group are reduced markedly. It showed that the higher dosage of low-power laser can restrain the produce of free radical in blood.

This paper reported 82 cases of oral mucoid cyst treated by CO2 laser. The cure rate was 100%. This treatment was a easy、safe、less pain and low tissue injured proudure.

Objective: To study the method and long-term curative effect of diode laser interstitial heat therapy for pituitary tumor by transnasal-sphenoidal approach conducted by CT or X ray. Methods: 805nm diode laser, output power of which is 25W, optical fiber is conducted by transnasal-sphenoidal approach through CT or X ray to have heat therapy. Results: Symptoms get better for all 3 patients, and endocrine indexs are normal. 1 patient has no pituitary tumor 1 year after operation, and 1 patient is made craniotomy 2 years after operation. Conclusion: This methods have advantage of simple manipulation, accurate location, slight injury, less complication, less painful and economics.