The plates are used as the elements with long focal depth,whose two important parameters*#:the axial intensity distribution and the axial variation of the focused-central-spot size,are simulated and analyzed*#.

It is necessary to study characteristics of axial intensity distributions, such as focal depth and focal shift, which influence the maximum energy efficiency obtained and the assembling error at the receiving plane.

Through the curve of half high width of normalized axial intensity via detector effective radius and incoherent incidence light effective radius,the optical sectioning property of confocal microscope was gotten.

Based on the Rayleigh diffraction integral and without use of the usual approximation,Rλ(λ is wavelength),an exact analytical expression for the axial intensity of nonparaxial Gaussian beams diffracted by a small circular aperture is derived.

1. Based on the Rayleigh diffraction integral and without use of the usual approximation, R≥λ(λ-wavelength), an exact analytical expression for the axial intensity of nonparaxial Gaussian beams diffracted by a small circular aperture is derived.

Detailed numerical calculations and analysis for the axial intensity distribution,refative focal shift and three-dimensional intensity distribution of focused Laguerre-Gaussian beams in the apertured case have been performed by using Collins diffraction integral.

Based on the expression for the axial light intensity of cosine-Gaussian beam by a lens with spherical aberration,the influence of the coefficient of the spherical aberration and Fresnal number of Gaussian beams on the axial intensity distribution is discussed.

Based on the fact that circ function can be expanded by an approximate sum of complex Gaussian functions with finite numbers,the analytical formula for the axial intensity distribution of a partially coherent Gaussian Schell model (GSM) beam through a circular lens with finite aperture was derived. The calculation was made and its results were compared to those of the diffracted integral.

This paper proposes an improved method for measuring the axial intensity of magnetic induction in a solenoid. This improvement not only makes the sensitivity of ballistic galvanometer 8.5 times higher, but also extends the lower limit of measurement range of B from 10 Gs to 1 Gs. In general, it limits the working current to the range from 0.1 A to 0.3 A which is used to measure K and B.

The normalized axial intensity minimum Imin / Imax decreases with an increase of α and β, and Imin / Imax remains unchanged as Nw varies.

Based on the generalized Huygens-Fresnel diffraction integral and the theory of partially coherent light, the axial intensity distribution and the focal shifts of focused partially coherent conical Bessel-Gauss beams are investigated.

Axial intensity distribution and focal shifts of focused partially coherent conical Bessel-Gauss beams

In a typical case of a 1010 W laser, the enhancement of axial intensity by a factor of 25 has been predicted in a length of 0.6 cm.

Numerical results concerning the far-field intensity distribution and the axial intensity distribution in the near-field region are presented in diagrams and discussed.

This paper proposes an improved method for measuring the axial intensity of magnetic induction in a solenoid. This improvement not only makes the sensitivity of ballistic galvanometer 8.5 times higher, but also extends the lower limit of measurement range of B from 10 Gs to 1 Gs. In general, it limits the working current to the range from 0.1 A to 0.3 A which is used to measure K and B.

The drag of fluid by dilute solution of linear macromolecules is lower than that of New Tonian fluid.This phenomenon was discovered by B.A. Toms early in 1948, and it is called drag reduction effect. It has wide- ranging benefits in the fields of national defence, industry, water con- servancy, water transport and fire fighting etc. This paper studies experimentally the turbulence structure of the flow of water and that of dilute solutions of linearmacromolecules in smooth channel by laser dopplemeter. According...

The drag of fluid by dilute solution of linear macromolecules is lower than that of New Tonian fluid.This phenomenon was discovered by B.A. Toms early in 1948, and it is called drag reduction effect. It has wide- ranging benefits in the fields of national defence, industry, water con- servancy, water transport and fire fighting etc. This paper studies experimentally the turbulence structure of the flow of water and that of dilute solutions of linearmacromolecules in smooth channel by laser dopplemeter. According to the results of experiments, influence of the linear macromolecules to the mean and pulsation structure of the flow is analysed, and on the basis of this, combined with abroad materials, drag reduction fundamentals of the linear macromolecules are preliminarily analysed.The results indicate that the following conclusions may be drawn: 1. The linear macromolecules of polypropylene have distinct drag re- duction effect, relative to New Tonian fluid, the mean velocity ((?)/u*) of the fluid of dilute solution of linear macromolecules increases distitic- tly, dray coefficient of it reduces and axial intensity (u′~2/u*)~(1/2) incr- eases distinctly. 2. By using laser dopplemeter to measure the turbulence parameter, the results are the same as the relevant abroad material. Theoretical for- mulas of turbulence parameter ofviscoelastic fluid put forward by Dou Guoren are identical with the results of the experiments. 3. According to New Tonian fluid, the correlation coefficient of u′, v′ is reduced by adding the linear macromolecules of polypropylene be- cause the drag coefficient of the viscoelastic fluid is reduced, that is, the decrement of turbulence drag τ=-ρ(?). The drag reduction in the vicinity of boundary is maximal, and in any position the turbulence drag is reduced too. 4. To a linear macromolecules, if the consistency of linear macromol- ecules is low, we can find the maximal drag reduction with the increase of consistency.And if the consistency outstrips this number, the drag re- duction decreases with the increase of consistency. So we should analyse the character of the linear macromolecules to obtain the optimum consist- ency and maximal benefit.

Analytic expressions for axial intensity distributions of a Bessel-Gauss beam focused by an aperture lens have been derived by using Coffins diffraction integral, and discussed by numerical calculations. As a limting case, the axial intensity distributions of a Bessel beam focused by an aperturelens have also been studied both theoretically and experimentally.