一种混合优化的匹配追踪生态声音识别方法

针对生态自然环境中噪声对声音识别产生干扰的问题,提出利用混合优化的匹配追踪(MP)进行生态声音识别的方法.首先,使用萤火虫算法(GSO)和粒子群算法(PSO)对匹配追踪算法进行混合优化,加快匹配追踪有限次稀疏分解的速度并重构声音信号,保留高相关成分,滤除低相关噪声;其次,根据所选最优原子的时频信息结合MFCCs提取复合抗噪特征;最后,结合支持向量机(SVM)对40种生态声音在不同背景噪声与信噪比的情境下进行分类与识别.实验表明,优化后的匹配追踪算法去噪性能优于谱减法和小波去噪法.与常用的MFCCs方法相比,本方法对生态声音在不同信噪比下的识别性能有不同程度的改善,并且具有较好抗噪性.     

Mechanism of surface texture evolution in pure copper strips subjected to double rolling

Developing ultra-thin copper foils with different surface roughness and microstructure has important significance for improving the service performance and reducing the production cost of high-end circuit boards. In this paper,pure copper strips with initial cube texture were subjected to a double rolling process(deformation amount ranges from 50% to 95%),and the surface textures evolution law and mechanism of doublerolled strips were studied by an X-ray diffraction technique. The results show that when a deformation amount increased from 50% to 70%,the grains of two surfaces rotate away from the cube orientation,and the formed textures of two surfaces mainly consisted of C,S and B orientation components. The orientation density values for these three components on bright surface only had slight difference; the orientation density values for C and S components were much larger than that for B components on a matt surface. When the deformation amount increased to 90%,the increase extents of orientation density values for C and S components were obviously larger than that for B components on a bright surface; the increase extents of orientation density values for these three components were almost the same on the matt surface. It has been found that when deformation amount reaches 95%,the grains orientation of bright surface were relatively concentrated,and the orientation density value for C texture obviously increased to 11.68 and that for B texture was only 3.15; the grains orientation of matt surface were relatively dispersed,and the orientation density value for C texture increased to 9.26 and that for B texture obviously increased to 6.35,and the density values of these two textures had less difference. For the condition of strong compressive and shear stress on the bright surface,grains were mainly rotating to C texture orientation; compared with the bright surface,"semi-free" deformation condition on the matt surface is beneficial to promote much more grains to rotate to the B texture orientation.     

Tubular pure copper grain refining by tube cyclic extrusion–compression (TCEC) as a severe plastic deformation technique

Tube Cyclic Extrusion–Compression(TCEC) method is a novel severe plastic deformation technique developed for grain refining of cylindrical tubes to ultrafine grained(UFG)/nanostructured ones. In this method, tubes are fully constrained and deformed between chamber and mandrel with a small neck zone. The principle of TCEC technique which was adopted to impose severe plastic strains to the tubular materials was explained. Also, the deformation and grain fragmentation mechanism during TCEC was analyzed. The material deformation characteristics during TCEC were numerically simulated by FE code of ABAQUS/Explicit. The FEM results demonstrated that TCEC technique was able to impose extremely high plastic strains. The TCEC method was successfully applied to a commercially pure copper(99.99%) and significant grain refinement was achieved. TEM observation demonstrated the refinement of grains from the initial size of 45 μm to 200–350 nm after four processing cycles of TCEC. Microhardness measurements were carried out across the thickness of the initial and processed tubes. The results show good homogeneity of hardness distribution and an increase to 102 Hv from initial value of 55 Hv after four TCEC cycles. Mechanical properties of the specimens were extracted from tensile tests. The obtained results documented notable increase in the yield and ultimate strengths, whereas the uniform and total elongations decreased. Fracture surfaces after tensile tests were investigated by scanning electron microscopy(SEM), and the observed morphology indicates ductile fracture mode after four cycles of TCEC.     

诗里诗外话清明——浅析寒食、清明节的文化内涵

唐宋时期以寒食、清明这两个传统节日为题材的部分诗歌,蕴涵着人类亲和自然,反观自身生命及人生意义的文化内涵。解读这类诗歌,可以发现许多超越节日具体的形式本身的更为广泛深在的文化意义与精神旨趣。     

纯迭加态的Berry相位

计算了纯迭加态的Berry相因素，其结果同简谐振子相干态的Berry相因素完全相同．同时指出，按Berry的最初理论由有限个简谐振子相干态迭加而成的态的Berry相因素同简揩振子相干态的Berry相因素也完全相同．     

不同落叶林林下凋落物的分解与养分归还

用分解袋法研究胡桃楸、落叶松纯林及其混交林下叶凋落物的分解及养分归还速率。结果表明：在1个生长季内，3种林分叶凋落物分解速率从大到小依次为：胡桃楸纯林、混交林、落叶松纯林。胡桃楸纯林叶凋落物归还氮的速率最快，落叶松纯林叶凋落物归还磷、钾的速率最快。二组成混交林后，混交林叶凋落物归还氮的速率较落叶松纯林明显提高，而归还磷、钾的速率较胡桃楸纯林明显提高。胡桃楸与落叶松混交后叶凋落物养分归还速率较其各自纯林的有所提高，可能是混交林增产机理之一。     

音程理论若干概念辨析

音程，是音乐基础理论中的一个基本概念，近年来一些乐理书中对其中若干概念的称谓、定义、种类、性质等的解释有值得商榷之处。就此谈了几点自己的意见和看法，供理论界、教育界广大同仁参考。     

从《雅歌》探析《所罗门之歌》中人物的追寻

《所罗门之歌》是美国黑人女作家托妮·莫里森的小说，发表于1977年。这部小说取名子《田约》中的《所罗门之歌》，又名《雅歌》。《雅歌》相传为所罗门王所作，讲述了男女之间热烈渴求和追寻对方的动人爱情故事。生活在百分之八十以上都为基督徒的美国。莫里森直接以《圣经》的一个文本命名自己的小说，是否有着特殊的寓意？本文从两部作品有关人物的追寻进行对比分析和探讨，以期对莫里森的这部小说进行更深刻的解读。     

浓墨重彩大手笔——蒙古族作家超克图纳仁文学创作概览

82岁高龄的超克图纳仁坚守文学天地逾60年，执著追求，成就卓然。他的创作取材时间与取材空间有致交织而构成的具有整体性的艺术画卷，其历史的纵深感与空间的宽广性，以特有的艺术魅力一同昭示着草原气派、草原精神；综观超克图纳仁的创作，是颇有草原气派的，或者说，他以自己的实践建树着真正的“草原文学”。超克图纳仁的文学实践，对当下有四点启示：一、作家独特的生活体验与审美发现的问题；二、社会责任感与艺术追求的问题；三、突出民族身份与兼容广纳的关系问题；四、勤奋多产与锤炼精品的关系问题。     

串级与Smith预估补偿相结合的控制系统研究

针对包含大滞后环节的喷雾干燥炉控制质量不佳的问题,提出廉价的串级控制解决方案,在内环与外环均采用通用的PID控制器。生产实践表明,这种串级控制系统不仅具有低成本的特点而且具有较好的控制效果。