蒸压砂加气混凝土砌块在节能建筑工程中的应用

蒸压砂加气混凝土砌块具有轻质、防火、保温、隔热、隔音、抗震、绿色环保等优越性能,可作为国家实现建筑物“三步节能”单一材料达标的一种产品,干作业、施工快、工期短,可降低工程成本,在建筑外墙外保温工程中采用时无需再做其他保温材料.     

Limitation of cracking in AAC masonry under the window zone

The article describes the results of tests on the impact of reinforcement on the appearance of cracks and on the manner of damage to masonry under the window zone. Masonry made of Autoclaved Aerated Concrete units with thin layer mortar was tested. Eight unreinforced test specimens (two series) and four series of test specimens (12 specimens) with reinforcement in the bed joints were subject to testing. Two types of reinforcement were used in the tests. It is demonstrated that the reinforcement has a significant impact on the level of cracking stress and propagation of cracks. It was found that when a pillar is correctly designed, cracks should not occur in the masonry under the window zone.     

MPEG-4 AAC实时编解码系统研究

介绍了音频编码的一般原理和常用的音频压缩方法,并简要论述了AAC编解码过程中要用到的感觉模型、TDAC技术和Huffman编解码。     

利用城市生活垃圾焚烧炉渣制备蒸压加气混凝土板材

以城市生活垃圾焚烧炉渣和石英尾矿作为蒸压加气混凝土板材的硅质原料,通过设计工艺配方和工艺参数控制,采用XRD和SEM对原料和试块的矿物相组成和微观形貌进行分析并测试相关的物理性能。试验研究表明:当工艺配比中焚烧炉渣:石英砂:石灰:水泥:石膏为39%:30%:15%:13%:3%时,所制作的砌块抗压强度符合GB11968-2006中B05、A3.5级蒸压加气混凝土优等品,可用于蒸压加气混凝土板材的制作。     

基于比例因子转移概率的AAC音频压缩历史检测算法

音频压缩历史的检测是音频取证的重要组成部分,对判断音频是否经过篡改和伪造有着十分重要的意义。通过研究发现,AAC音频比例因子的值会随着压缩次数的增加而逐渐减小。基于此,提出了一种基于比例因子转移概率差值统计特性的AAC音频压缩历史检测算法。实验结果表明,该算法能对多次压缩的AAC音频进行准确分类,其低码率转高码率间AAC音频平均分类准确率达到了99.75%,同码率间准确率达97.28%。另外,对比实验也证明了本文算法的性能优于现有算法。     

基于MPEG-AAC编码器的压缩域音频增强方法

本文基于MPEG-AAC音频编解码器,提出了一种压缩域的音频增强方法.首先,对含噪音频信号的比特流进行解码,得到含噪音频信号的MDCT系数;然后,利用修正的加权递归平均（Modified Weighted Recursive Averaging,MWRA）方法估计噪声功率;再者,利用基于听觉掩蔽原理的自适应β-阶双曲余弦（COSH）统计模型,对含噪音频的MDCT系数进行增强处理;最后,将增强后的MDCT系数重新量化编码,得到用于解码的增强比特流实验结果表明,本文提出的方法能有效去除AAC解码音频信号中的多种背景噪声,其性能明显优于参考方法.     

MPEG-4 AAC解码器在NIOS Ⅱ平台上的实现和优化

给出了MEPG-4AAC实时解码器在NIOSⅡ平台的实现方案，介绍了MPEG-4AAC—LC解码算法及各关键模块优化算法。在完成实时解码要求下，结合NIOSⅡ平台特性，对解码器在软件代码与处理器上进行优化。实验结果表明CPU时钟为80MHz时能达到实时解码要求。     

基于微处理器核的媒体系统芯片结构设计

围绕基于微处理器核的AAC解码器结构设计展开讨论，对IP定制、数据通路及存储设计进行了研究，并成功开发了一个基于微处理器核的MPEG-4AAC解码系统芯片。     

Breeding strategies for improving the performance and fruit quality of the pepino (Solanum muricatum): A model for the enhancement of underutilized exotic fruits

The pepino (Solanum muricatum Aiton) is a neglected Andean crop that has elicited an increasing interest from exotic fruit markets. The pepino is highly diverse and, by using appropriate breeding strategies, it has been possible to develop new improved materials. Here we review more than a decade of efforts and advancements made in the genetic improvement of the pepino for several traits, with special emphasis on fruit quality. Different strategies, like the use of a wide diversity of genetic resources, exploitation of genotype × environment interaction, use of clonal hybrids, and introgression of genes from wild species, have facilitated significant developments in enhancing the commercial potential of the pepino, and have allowed the development of new cultivars and breeding materials adapted to new agroclimatic conditions. Agronomic performance of the pepino has been improved by the use of genetic parthenocarpy, selection for resistance to Tomato Mosaic Virus, and by developing hybrids, that manifested heterosis, but also did not have lower quality fruit. Breeding for quality has been focused mostly on the improvement of flavor (sweetness and aroma) and nutritional value (ascorbic acid content; AAC). Despite the limited intraspecific diversity available for sugar content, materials with high soluble solids content (SSC) have been selected. Strategies for further increases of SSC and titratable acidity have been based in the use of wild relatives. The study of variation within the cultigen was also helpful in the selection of hybrid genotypes with improved aroma profiles and high AAC values. As a result of the breeding efforts, several cultivars with improved agronomic performance and fruit quality have been produced. The use of biotechnological tools represents an opportunity to use the extensive genomic information compiled for related species, like tomato or potato, for the future improvement and enhancement of pepino quality. The results obtained in the pepino show that ample opportunities exist for improving the commercial potential of under-utilized fruits by means of breeding based on the exploitation of genetic diversity.     

Adaptive TCX Windowing Technology for Unified Structure MPEG‐D USAC

The MPEG‐D unified speech and audio coding (USAC) standardization process was initiated by MPEG to develop an audio codec that is able to provide consistent quality for mixed speech and music contents. The current USAC reference model structure consists of frequency domain (FD) and linear prediction domain (LPD) core modules and is controlled using a signal classifier tool. In this letter, we propose an LPD single‐mode USAC structure using an adaptive widowing‐based transform‐coded excitation module. We tested our system using official test items for all mono‐evaluation modes. The results of the experiment show that the objective and subjective performances of the proposed single‐mode USAC system are better than those of the FD/LPD dual‐mode USAC system.