激光具有较高的能量且单色性较好,因此被广为应用在弱光波前探测系统中.但激光的强相干性产生的像面散斑会造成CCD面阵上的光强无规律分布,导致波前重构质心算法的错误,进而降低波前像差探测的精度.分析了激光散斑降低波前探测精度的原因,并尝试用旋转散射体、多模光纤耦合及随机位相板等多种组合方法消除激光散斑,提升波前探测精度.评估几种方法对光强、光均匀性及消除散斑的效果进行对比分析、优化设计激光为光源的波前探测消散斑系统.最后利用随机位相板与多模光纤耦合的方法有效消除激光散斑,并进行消散斑前后的波前探测.该消散斑系统可有效消除激光散斑并提升波前探测精度,大幅提升了激光光源在自适应光学领域的应用性.
Spice is obtained from the seeds,buds,leaves,the root block or its extract processing of plants,with a pungent smell,volatile oil,spicy ingredients,and organic acid,fiber,starch grains,resin,mucous substances and other ingredients.Most of its flavor done from the distillation of essential oils,energy giving food to taste,increase appetite,help digestion and absorption.This paper reviewed the research progress of spices and extracts on antioxidant,food color protection and food preservation.Food products prone to spoilage and produce toxic and hazardous compounds,it discusses the effect of spice in improving food security.
This paper considers some scheduling problems of single machine and two parallel machines with deteriorating effect,learning effect and an availability constraint.In such problems,the actual processing time of a job depends not only on its basic processing time but also on its scheduled position and starting time.Moreover machines may be unavailable because of preventive maintenances and periodical repairs,namely,the machine availability constraint.Machine conditions are perfectly restored to its initial state after the maintenance activity.The objective is to minimize the total completion time.We study the case that the machine is unavailable at any time.We consider a single machine scheduling problem with only once maintenance.We also consider a two parallel machines scheduling problem in that one machine is unavailable.Two pseudo-polynomial dynamic programming algorithms are proposed to solve the above problems respectively.Specifically,we give a polynomial time optimal algorithm with O(n4)for the two parallel machines scheduling problem,in which one machine is unavailable at time zero and anther is always available.Finally,we give a numerical example to illustrate its calculation process.
In order to improve the health function of yoghourt,composite yoghourt was made by using watermelon juice,purple rice and defatted milk powder as materials.The effects of mixed fruit pulp,xylitol dosage,inoculation amount and proofing time on the quality of the composite yoghourt were investigated,and the optimum formula was decided through the orthogonal experiment and the sensory index of the product was evaluated.The results show that adding amount of the mixed fruit pulp had the greatest influence on the sensory evaluation,followed by xylitol dosage,inoculation amount and proofing time.The optimum formula for preparing the yoghurt was as follows:the ratio of watermelon juice and purple rice was 3∶1,the adding amount of the mixed fruit pulp was 40%,the xylitol dosage was8%,the inoculation amount was 5%,and when they were fermented for 4hthe quality of the produced yoghurt was best.
Thin-walled aluminum alloy casting shell has been widely used in aerospace and aviation,etc.Although machinability is good,it still has many disadvantages such as the complex structure,low hardness,poor rigidity,deformation easily during machining,and hard control for machining quality.So the machining of thin-walled aluminum alloy casting shell is a technological difficulty.To solve these problems,this article first make a brief description and analysis on the main factors causing deformation,which are residual stress,tool angle,workpiece clamping,and part material of parts.According to these deformation factors,technology requirements are supplied as following:the tool and its trajectory should be optimized to improve the machining quality and efficiency,such as choosing the proper tool material,increasing the rake angle and clearance angle、decreasing the friction of tool and workpiece when cutting and decreasing cutting stress;By making use of auxiliary facilities and the clearance of sequence process,stress can be released,so as to reduce deformation caused by machining process;Optimize fixture by making it to contact with part by surface to guarantee equal force and avoid deformation;The three elements of finish turning are limited,that is cutting depth,speed,and feed.Using the above technology can effectively reduce the deformation of aluminum alloy thin-walled shell,so as to meet the design requirements.
