short time diffusion 中文意思是什麼
short time diffusion
解釋
短時間擴散-
Pulse electric current heat treatment ( pecht ) developed by sodick, ltd., of japan, is a recently developed material processing method which consists of spark plasma sintering and welding, plasma activated sintering and welding, big pulse electric current ( bpec ) diffusion welding etc. the following are basic merits of pecht : rapid heating and cooling ; short sintering or welding time ; lowering sintering or welding temperature
脈沖電流熱加工（ pulseelectriccurrentheattreatment ，比如燒結，焊接等）是九十年代發展起來的一種材料快速制備新技術，它包括放電等離子燒結與焊接、等離子活化燒結與焊接、脈沖大電流擴散焊接等。它具有升溫、降溫速度快、能在較低的溫度下燒結或焊接以及時間短的特點。 -
In the section 2, firstly based on the diffusion approximation theory, the temporal characteristics of the reflectance and the transmittance were theoretically analyzed in turbid tissues ; secondly, the curves were simulated that the intensity and the pulse shape of the time resolved reflectance and transmittance versus the absorption a, the scattering s and the anisotropy coefficient g in two different boundary conditions : semi - infinite turbid media and homogeneous slab ; at last, the optical properties can be derived from the curves ; in the section 3, the conditions of ultra short laser pulses of different pulse - width and shapes has been theoretical analyzed and calculated, besides, the simulated the curves of the intensity and pulse shapes of the reflectance and transmittance in a homogeneous slab are obtained for use and future studying
第二章中首先根據漫射近似理論對超短脈沖在以生物組織為典型的混濁介質中傳輸進行了理論分析，然後對兩種邊界條件下產生的漫反射、漫透射光脈沖強度和形狀隨各光學特性參數的變化情況進行了數值模擬，最後得到了混濁介質的光學特性參數與漫反射、透射脈沖強度與形狀的關系曲線。第三章對不同形狀和脈寬的脈沖光源入射到混濁介質中產生的漫反射、漫透射脈沖的強度和形狀進行了理論分析和數值模擬，並將高斯脈沖與方波脈沖情況進行了對比，得到了各種情況的漫反射、漫透射脈沖強度、形狀與各光學特性參數的關系曲線，這對從分析脈沖形狀中提取介質的光學特性參數的信息有重要的意義。
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