Wyniki wyszukiwania - BazTech

1

Light Effect in Semiconductor Bridge Plasma Ignition

Zhang L., Li N., Wan Z., Zhu S.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 4

996--1006

EN

Heat is considered to play an important role in Semiconductor Bridge (SCB) plasma ignition. Nevertheless, in this paper a non-heat effect is reported for SCB ignition of primary explosives. An initial comparison showed that there is no reasonable correlation between the ease of plasma ignition and the 5-s explosion temperature. Meanwhile the addition of Pb3O4 was found to make lead styphnate (LS) more active to SCB plasma ignition whereas the heat decomposition of this mixture was not accelerated. In terms of the phenomena mentioned above and the response of primary explosives to SCB plasma, we propose an effect of light in SCB plasma ignition. The free radical concentration change indicates that light enhances the activity of primary explosives in SCB plasma ignition. Regarding the mixture of LS and Pb3O4, the additive itself does not make LS sensitive to the SCB plasma. However, the supplement makes LS active under light exposure. As a result, the effect of light on SCB plasma ignition was confirmed by the experiments conducted in this study. This paper provides a new understanding of SCB plasma ignition from the viewpoint of explosives, which is of importance for the design of SCBs.

2

Optical switch based on cascaded SOI nonlinear directional coupler

Tao Q., Luo F., Cai D., Liang Q., Wan Z., Song X., Liu X.

Optica Applicata

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2011

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Vol. 41, nr 3

669--678

EN

In this paper, we calculate three effective refractive indexes for cascaded silicon-on-insulator (SOI) nonlinear directional coupler. For each effective refractive index, the coupling length LC, core-to-distance-ratio K and switching threshold power Pi, m are calculated, respectively. However, there are some fabrication errors, which are ?W, ?H, ?K in the height of Si layer and width of Si layer and error of core-to-distance-ratio. We have analyzed the influence of power transmission efficiency Ti, j and relative transmission efficiency error ?i, j caused by the change of ?W, ?H, ?K. Furthermore, we find the tolerance range of ?W, ?H, ?K for Ti, j and ?i, j in couplers a, b, c. The other four input pulses with different powers are switched to four different ports. Although output pulses show some little compression and loss, the value of ? is very small and output pulse waveforms are not affected seriously. The basic switching function has been realized, so this design is proved to be effective.

3

Conjugate numerical investigation of a miniature flat-plate evaporator of a capillary pumped loop for electronics cooling

Wan Z., Liu W., Tu Z., Nakayama A.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2008

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Vol. 12, No 1-2

5-19

EN

A capillary pumped loop (CPL) is a two-phase thermal control device applied in cooling electronic devices. A two-dimensional conjugate numerical model of a miniature flat-plate capillary evaporator is presented in order to describe liquid and vapor flow, heat transfer and phase change in the porous wick structure, liquid flow and heat transfer in the compensation cavity and heat transfer in the vapor grooves and the metallic wall. The entire evaporator is solved with the SIMPLE algorithm as a conjugate problem. The shape and location of the vapor-liquid interface inside the wick are calculated, and a side wall effect heat transfer limit is introduced to estimate the evaporator's heat transport capability. The influence of various wall materials on the evaporator's performance is discussed in detail. The results suggest that an evaporator with a combined wall is capable of dissipating high heat flux and stabilizing the temperature of electronic devices at a moderate temperature level.

4

Braided angle measurement technique for three-dimensional braided composite material preform using mathematical morphology and image texture

Wan Z., Li J.

Autex Research Journal

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2006

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Vol. 6, no. 1

30--39

EN

This paper describes a new measuring algorithm for estimating the exterior average braided angle of a three-dimensional (3-D) braided composite material preform] based on image texture. In this project, an advanced filtered algorithm for an image of a 3-D braided composite material preform is developed on the basis of mathematical morphology. Median filter algorithms for mathematical morphology are applied in the system. The polar spectrum and main properties are investigated in the paper. Theory shows that a rotated texture's polar spectrum is an approximate translation of the unrotated texture's polar spectrum, and that the degree of each translation approximates to the corresponding rotation of the surface. The system was tested on both carbon and glass fibre preforms. We have obtained very encouraging experimental results, which show that the proposed method is feasible. So far, the research is a new development for measuring 3-D braided composite material preforms. The work will lay the foundation for establishing a test standard for 3-D braided composite material in China.

5

On-line technique for measuring thickness for three-dimensional braided composite material preforms

Wan Z., Li J.

Autex Research Journal

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2005

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Vol. 5, no. 4

236--246

EN

This paper presents an automatic method that can measure the thickness of three-dimensional (3-D) braided composite preforms. The thickness of 3-D braided composite material preform is an important parameter of 3-D braided composites. With the development of 3-D braided composite technology, an automated measurement technology for thickness of braided composite preform has become an importantgoal. The objective of this paper is to present an automatic measuring system. The system we devised consisted of a computer, a proximity sensor, a pressure sensor, an analog-to-digital converter and pulse motor, etc. The measuring principle and results are discussed in the paper. The system was tested on both carbon and glass fibre preforms. We obtained very encouraging results. Experiments showed the pressure and eddy current resistance value are important parameters for measuring the thickness of 3-D braided composite material preforms. The measuring precision is higher when the pressure value ranges from 0.6kg/cm2 to 0.8kg/cm2 and the eddy current resistance is 2kW for preforms made of carbon-fibre than of other substances.