自适应最优量化查找表预失真算法

为了在不增加查找表（LUT）长度的前提下,进一步改善功率放大器非线性性能,提出1种自适应最优量化LUT的预失真算法.与已有的最优量化LUT算法不同,该算法综合考虑了预失真器特性和输入信号概率分布,理论分析并得到了最优的LUT量化间隔,并给出了全盲条件下的自适应预失真器LUT参数搜索算法.仿真表明：应用该算法的预失真系统的归一化最小均方误差指标优于均匀量化LUT算法和已有的最优量化LUT算法,尤其是在输入信号功率回退较大的情况下,该算法的预失真效果改善更为显著.     

Macrostructure and properties of thin walled copper tubes prepared by the downward continuous unidirectional solidification method

The macrostructure and properties of the thin walled copper tube prepared by the downward continuous unidirectional solidification (DCUS) method were studied. The result shows that the macrostructure is closely related to the solid-liquid interface profile, which is influenced by the distance between the cooling water location and the solidification front. The mechanical properties of the thin walled copper tube prepared by the DCUS method are near those of the normal cast copper, and it has good relative density, electrical conductivity, and elongation, which are not greatly affected by casting speed. The thin walled copper tube prepared by the DCUS method also has good processing properties that can be taken to further drawing procedures directly without an intermediate process, and obtains good mechanical properties with the total processing rate of 89.8%.     

Preparation,characterization and release of methyl viologen from a novel nanoparticle delivery system with double shells of silica and PLGA

The use of nanotechnology in drug delivery is a rapidly expanding field. Biodegradable or nontoxic nanomaterials have the most promising application potentials in nanomedicine. Herein, we report a novel core-shell nanoparticle with double shell coatings (silica and poly(D,L-lactide-co-glycolide) (PLGA)) with the total shell thickness of (8.7 ± 1.3) nm. The outer shell of PLGA is biodegradable and used for controlled and sustained release, and the inner shell of silica is mesoporous for the preservation of t...     

着陆器软着陆垂直冲击试验研究

月球着陆器着陆过程中会产生巨大的冲击作用,影响其内部精密仪器的正常工作,且着陆安全性问题决定着着陆任务的成败,因此,研究着陆器软着陆过程中与月壤的动力响应具有重要意义。文章首先基于对着陆器着陆冲击过程研究,建立了着陆器与模拟月壤相互作用理论模型;之后,利用自主研发的着陆冲击试验系统,采用半球形足垫(简称“足垫”)模拟着陆器缓冲支腿,通过垂直着陆冲击试验,对冲击模拟月壤过程中足垫的着陆质量和冲击速度对着陆冲击过程的影响进行了详细研究。研究结果表明,模拟月壤密实度一定,较大的着陆质量能有效提高着陆器冲击机械能的耗散效率;冲击速度越大,着陆器在单位时间内转移到模拟月壤的动量越多,模拟月壤颗粒对着陆器产生的作用力越大;冲击能表征了着陆质量和冲击速度,对垂直着陆冲击过程有很重要的影响。最后,通过试验结果与理论模型对比,对着陆器与模拟月壤的动力学模型进行了验证。文章的研究结果可为设计安全载人登月月面着陆器提供必要的试验数据与理论参考。。     

求解混流装配线调度的疫苗共生克隆选择算法

针对混流装配线的多目标调度优化问题,提出了一种疫苗协同进化的多目标免疫克隆选择优化算法.设计了疫苗种群及其相关操作,使其跟抗体种群相互影响并协同进化,提高了算法的性能;针对调度优化问题的离散性,选择同时从抗体的基因型和表现型评价抗体亲和度;依据抗体质量和进化代数,设计了自适应变异率;在每次迭代过程中,通过多次局部寻优加快算法收敛速度.最后通过两组实例仿真,与另3种多目标优化算法进行比较,结果证明该算法可得到更好的计算结果.     

Soft X-ray optical multilayer mirrors

The current research on the structure design, characterization and structural stability of soft X-ray optical multilayermirrors is reviewed and further studies on the currently existing problems and the possible solutions are made.     

垃圾处理的能值分析

采用能值分析方法,对处理垃圾的几种常见方式进行了分析,并对其系统的能值投资率(EIR)和能值产出率(EYR)进行了计算．结果表明,填埋及沼气发电、焚烧发电的EYR稍大于1,堆肥系统的EYR小于1．填埋及沼气发电、焚烧发电虽然显示出一定的应用前景,但它们的EYR还偏小,这说明目前我国垃圾处理系统的运行还离不开政府的支持与新技术的应用．堆肥系统的EYR较小,但由于它的EIR也较低,可以以较低的社会能值投入达到垃圾处理的目的,因此目前暂时也有它存在的价值．     

纳米晶稀土永磁材料的理论,制备及应用研究

本文系统综述了作者近年来在纳米晶稀土永磁材料领域所取犁 进展,包括理论,制备及应用等几方面,并对今后该领域的研究与发展提出了值得重视和努力的方向。     

Response characteristics of sonar receiver under intense sound pulse

For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control (AGC) circuit and the survivability of the prime circuit under strong interference are analyzed by simulations and experiments. An AGC simulation model based on the voltage control amplifier VCA810 prototype is proposed. Then static and dynamic simulations are realized with single frequency signal and linear frequency modulated (LFM) signal commonly used in the active sonar. Based on intense sound pulse (ISP) interference experiments, the real-time response characteristics of each module of the receiver are studied to verify the correctness of the model as well as the simulation results. Simulation and experiment results show that, under 252 dB/20 μs ISP interference, the specific sonar receiver will produce sustained cut top oscillation above 30 ms, which may affect the receiver and block the regular sonar signal.     

柴油乘用车燃用丁醇燃料道路工况气态物排放特性

基于PEMS(performance and emission monitoring system)车载排放测试方法,在一辆柴油乘用车上分别燃用纯国Ⅳ柴油、正丁醇的体积分数分别为10％和20％的正丁醇和纯国Ⅳ柴油的混合燃料,利用日本Horiba公司的OBS-2200车载气态排放物测试系统,对车辆尾气进行直采.通过对比不同道路类型下3种燃料气态排放物的排放因子,分析柴油乘用车燃用丁醇柴油的车载实际道路排放特性.试验结果表明,柴油乘用车燃用丁醇柴油可以明显降低一氧化碳排放,明显减小中高速工况下一氧化碳的峰值,总碳氢排放会随丁醇掺入比例增加而增多;二氧化碳的排放基本不变;发动机参数及工况的改变对氮氧化物的排放影响不大.