三表远传系统中信号检测电路设计与应用

文章介绍了三表远传系统中煤气表、水表信号的干簧管传感器型电路检测与处理方法,具有电路简单、价格低廉、性能可靠的特点;同时简要介绍了利用AD7757进行电能信号检测的应用电路。     

量子可逆逻辑电路综合的快速算法研究

可逆逻辑有许多应用,尤其在量子计算领域,量子可逆逻辑电路是构建量子计算机的基本单元,量子可逆逻辑电路综合就是根据电路功能,以较小的量子代价自动构造量子可逆逻辑电路.文中结合可逆逻辑电路综合的多种算法,提出了一种新颖高效的算法,自动构造正极性Reed-Muller展开式(RM),在生成量子可逆逻辑电路的解空间树上,采用总体层次遍历,局部深度搜索,借鉴模板优化技术,构造限界函数快速剪去无解或非最优解的分枝,优先探测RM中的因子,以极高的效率生成最优电路.以国际公认的3变量可逆函数测试标准,该算法不仅能够生成全部最优电路,而且运行速度远远超过同类算法.     

磁控位移传感器设计与开发

液压支架是综采工作面的主要设备,其推移位置的准确性决定着采煤工作是否能够正常进行。通常液压支架的推移由推移油缸来完成。为了准确测量其推移位置,本文设计并开发了一种用于液压支架推移油缸的磁控位移传感器。基于磁环控制测量杆内干簧管通断的原理,就可以将位移转变成电压信号。改变磁环的位置,相对应的干簧管导通,输出电压随之改变。传感器量程为100cm,相对误差为0.8%,线性度约为0.0958%,输出电压波动范围为±0.001V。实验室和现场试验结果表明：磁控位移传感器运行稳定,测量精度高,满足了综采工作面液压支架位移的测量要求。     

共振消声器吸收压力脉动的动态分析及仿真计算

研究了一种共振消声器———亥姆霍兹共振消声器。首先建立了共振消声器的数学模型,从频率特性角度讨论了共振消声器对压力脉动的削减作用,最后使用MATLAB进行了仿真计算,得到了三种脉动频率下压力脉动的削减幅度,其计算结果与仿真结果基本吻合。     

低时延RS-CC级联码的设计与实现

为提高手持无线电台的纠错和时延特性,考虑设计一种短码长RS-CC级联码.通过对Reed-Solomon码缩短和截断以及对卷积码删余,提出了一种低时延的级联码设计方案,并进行性能分析和软硬件实现.结果表明,在高斯信道下,当Eb/No达到4.2 dB时,能够实现10-4的误码率性能.设计的RS-CC级联码码长较短,编解码固有时延低,译码速度提升30％,适合低时延应用.     

The humidity buffer capacity of clay–sand plaster filled with phytomass from treatment wetlands

The aim of our study was to measure the amount of moisture absorption and desorption in clay–sand plaster mixed with “fibre-wool” from Typha spadixes and chips of Typha and Phragmites. Common cattail (Typha latifolia) and common reed (Phragmites australis) are the most common plants in constructed and semi-natural wetlands for wastewater treatment, as they are highly valued in ecologically oriented construction. The cattail and reed for the experiment were harvested in a wastewater treatment subsurface flow semi-natural wetland and in two free water surface constructed wetlands which showed reliable aboveground phytomass production over a 5 years period (for Typha, 0.37–1.76 kg DW m⁻² in autumn and 0.33–1.38 kg DW m⁻², and for Phragmites, 0.61–1.32 and 0.61–1.02 kg DW m⁻², respectively). The quantity of moisture absorption and desorption was measured in a climatic chamber where the humidity of ambient air was suddenly raised from 50% to 80% (absorption) and reduced from 80% to 50% (desorption). Over 12 h, all of the samples released the same amount of water as they absorbed. The clay–sand plaster samples absorbed slower than they desorbed, whereas the gypsum wallboard required significantly more time for desorption. Added phytomass gave positive effects by reducing the weight of the clay–sand plaster, accelerating and increasing moisture absorption.     

ANALYSIS OF THE DEFLECTION OF REEDS IN AUTOMOTIVE HYDRAULIC SHOCK ABSORBERS

0 INTRODUCTIONAn automotive by~ic shock absolver is an import unit of suspension, can damp the vibndion Offare and lady qUickly, and improves ride and handling c~teristics. Many shock absorbers use reedsas extension and compression valve, because they can s~ify the structure of shock absorbers. To get thereopired rebound and compression resistance, the different thick reeds ~ overlaPPed together. In older tOfomeast foe oh~teristics of the shock absorber, many rese~hers are striating for…     

Environmental Monitoring of Spatio-temporal Changes Using Remote Sensing and GIS in a Mediterranean Wetland of Northern Greece

Loss and degradation of terrestrial and aquatic habitats and degraded water quality are major environmental concerns worldwide. Especially wetlands are sensitive ecosystems that are subject to stress from human activities. Remote sensing techniques have been primarily used to generate information on land cover/use changes. Geographical Information Systems (GIS) and remote sensing can be used to provide a rapid or a large-scale understanding of lake change and in developing lake management strategies. The principal objectives of this study are to monitor and assess the spatial and temporal changes in land cover/use by using GIS, and to determine the main environmental factors affecting these changes. This paper presents a case study for the application of integrated remote sensing and GIS data for the classification and monitoring of the spatial and temporal changes in land use types. The study was conducted in a small natural wetland of Lake Cheimaditida, located in the East Mediterranean region of Northern Greece. Data analysis was conducted using GIS software. During the past several decades Lake Cheimaditida wetland has been influenced by many anthropogenic activities. The variables chosen for the assessment included condition of wetland and lake areas, present extent of wetlands relative to historic area, cover of natural habitat, wetland disturbances, etc. These variables address catchments properties that are important for maintaining and improving wetland habitats and water quality and assessment of trends useful for environmental monitoring. Land cover/land use patterns were assessed and compared using aerial photographs taken in 1945, 1969, 1982, and 1996. Over this period, reed beds enormously increased by 1,655.19%, while open-water areas and peat lands decreased by 74.05 and 99.5%, respectively. The significance of the changes in land cover distribution within the Lake Cheimaditida wetland are discussed in relation to the historical pattern of reed beds colonization, the importance of Phragmites australis in the process and the implications for strategic management of freshwater wetland resources.     

Reed canary grass yield and fuel quality in Estonian farmers’ fields

Reed canary grass (Phalaris arundinacea) is one of the possible raw materials for bioenergy production in northern Europe. Its cultivation is favoured because its high productivity and local origin. However, problems with the biomass quality for combustion have been reported. Usually delayed harvest in spring is suggested to improve the quality and decrease the moisture content of biomass. On the other hand, the feasibility of spring harvest depends on local climatic conditions and may cause yield losses. In current paper we studied reed canary grass fields in Estonia locating on different soil types and cultivated with various varieties. The influence of several fertilisation schemes on biomass yield was analysed. Our results indicated that production was higher on mineral soils than on the organic soil of abandoned peat extraction sites. Even different types of fertilisation did not increase the production on organic soils to the level comparable to those on mineral soils. Among studied varieties ‘Venture’ had the highest production. The highest yield per area was obtained late in the autumn (12.7 t d.w. per ha and 7.2 t d.w. per ha on mineral and organic soils, respectively). By spring the amount of biomass had decreased in all studied sites. Due to wet soil some of the fields remained unharvested, the others had high yield losses during practical harvesting. The chemical analyses did not reveal significant differences in the composition of biomass between late autumn and spring. Therefore we conclude that late autumn harvest should be preferred in local climatic conditions.     

TD—LTE系统Reed—Muller译码的仿真及FPGA实现

主要基于FPGA实现TD—LTE系统中的Reed—Muller译码,包括Reed—Muller译码的介绍、方案的构成、FPGA实现流程、以及实现结果分析。并在Virtex-6芯片上,进行了仿真、综合、板级验证。实现结果表明,该Reed—Muller译码算法应用到TD—LTE射频一致性测试仪表中具有良好的高效性和可靠性。