SUMMARY This paper reports on a semi‐analytical/numerical method to model sloshing water in an arbitrarily shaped aqueduct. The water motion is assumed to be inviscid, compressible, and linear (small displacement). The transverse sloshing fluid in an aqueduct is equivalently simplified as a fixed rigid mass M0 and a mass–spring system (M1, K1). According to a rule that the actual fluid (computed with finite element model) and its equivalent mechanical model have the same first sloshing frequency and acting effects on the aqueduct, the analytical solutions of the fixed (impulsive) mass M0, sloshing (convective) massM1, spring stiffness K1, and their locations in the aqueduct body are acquired by the least squares (curve fitting) algorithm. Applying this equivalent principle, the equivalent mechanical models are respectively obtained for the sloshing water in rectangular, semicircular, U‐shaped, and trapezoid aqueducts. The equivalent principle and fluid models are validated through comparison investigations involving rectangular and U‐shaped aqueducts. The dynamic properties and seismic responses of the original and equivalent systems are simulated, compared, and discussed for a U‐shaped aqueduct bridge. The main purpose of this paper is to provide a simplified model of sloshing fluid for the seismic/wind‐resistant computation of the support structures of the aqueduct bridge. Copyright © 2011 John Wiley & Sons, Ltd.

This paper presents a novel method to fabricate circular gratings based on binary optics. A smart digital micro-mirror device (DMD) laser writing system is used to fabricate circular gratings. By use of the DMD system, we are capable of making low-cost and useful circular gratings easily. Their levels and radii can be controlled and be suited for many optical systems. Experiment results have been obtained with two and four levels. In this paper, it will also show a method of simulating circular gratings' diffraction. Using the simulation method, we can value and check the diffraction effect of circular gratings to rectify the design parameters.

Using DMD system to make circular gratings and arrays is based on the character of Space Light Modulation (SLM) of DMD chip which can control the reflected lights based on the input figures' gray-scale. Firstly, circular gratings are simulated in a computer with some simulation software programmed in VC. Then, the figures are inputted in the DMD chip. With the character of SLM of DMD chip, the reflected lights can be controlled according to the circular gratings' gray-scale. The circular gratings can be obtained after being developed, fixed and etched. Many contrast experiments are carried out to confirm the technique parameters of circular gratings, as well as fabricate the two levels, four levels and array of circular grating. By use of this method, we are capable of making low-cost but useful circular gratings easily. Their levels and radii can be controlled, which will be suited for many optical systems.Compared with scoring mechanically, lithography and e-beam etching, binary optical methods are more convenient, efficient and low-cost.

In this paper , the reconstruction precision of Radon transform iteration based on beam-deflection optical tomography , which is used for 3-D temperature fields , has been studied by computer simulation on the prior knowledge of these fields. As an example , the method has been used to reconstruct the arc temperature fields

SThis paper presents the apppliation of optical epoxy resin as transfer medium to duplicate the relief hologram onto the hard base material. Experiments have been conducted on photo sensitive and thermal sensitive resins in relief hologram duplication. The results have shown that the diffraction efficiency and spatial frequency of the duplicated hologram are approximate to those of the origiral ones, and its environmental stability is satisfactory. The new one-time transfer duplicating technique , its simple process and low investment offer a practical value in massduplicating production.