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31.
潘多 《农业机械化与电气化》2010,(2):37-39
阐述PLC控制中央空调水泵变频调速系统的运行原理及构成要素，介绍具体电路、硬件电路和软件设计的步骤和方法。采用模块化设计结构，在可靠性和精度方面能达到使用要求。逻辑功能通过软件实现，系统运行可靠性得到提高。该系统具有开放性好、可扩充能力强、可靠性高、安装调试方便等优点，具有良好的发展前景。 相似文献
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The poor technological performance of weak wheat flours means that they are usually considered difficult to be transformed into satisfactory bread. During milling, there are several settings that can affect flour characteristics. In this study, we tested two operative parameters that have the potential to affect flour quality – stone rotational speed and wheat tempering. Tempering moistures were set at 11%, 13%, 15%, and 17%, while stone rotational speeds were set at 173, 260, and 346 rpm. Both factors were found to affect operative milling parameters, notably flour yield, process productivity and specific energy consumption. Grain moisture had a significant effect on both dough rheology and bread characteristics (dough stability, tenacity, and extensibility). Dough stability was maximum at 13% moisture. Dough tenacity decreased as moisture increased, while extensibility increased as moisture increased. Bread specific volume and crumb specific volume were improved at 13% and 15% moisture. In conclusion, wheat tempering can be used to improve the potential of a weak flour and bread characteristics, while stone rotational speed affects operative parameters and white flour yield. 相似文献
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水源热泵广泛应用在大中型的中央空调中,但在户式中央空调的应用中受到了一些因素的制约。为此,通过工程实例技术性和经济性的比对分析,指出了水源热泵技术应用于户式中央空调的可行性,对水源热泵技术的发展前景进行了展望。 相似文献
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针对移行材和早材皱缩等主要气干缺陷,拟定出赤桉半干材的干燥工艺,窑干前进行回复皱缩和减小表面硬化的汽蒸处理,窑干至目标含水率时进行终了调湿处理.结果表明:汽蒸预处理可以有效地回复皱缩材和显著地减小表面硬化;5 d内将试材的平均含水率25.61%下降到11.72%;3 h的汽蒸处理和24 h的湿空气处理均可有效地减小含水率梯度和残余塑性变定,但后者效果更佳;板材干燥质量达到国家标准二级质量的要求. 相似文献
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The equilibrium moisture content (EMC) of six wood species under desorption conditions of 20°C and 100% 0% relative humidity (RH), and the rate of adsorption at various depths of three wood species blocks under 98% RH at 22.5°C were studied. There were no significant differences among the EMC values for these six wood species over the RH range 40% 0%, but there were highly significant differences over the RH range 100% 50% at constant 20°C. The amount of moisture absorbed in the wood decreased curvilinearly with the increase of depth in the specimens as sorption time increased, and their relation could be represented by a semilogarithmic equation. Time-dependent adsorption behavior at various depths of the wood specimens could be represented by an exponential equation as a function of the product of the difference between moisture contents at equilibrium and initial conditions and the term (1 – e–t/). The value of of various wood species was found to increase linearly with the increased depth of the specimen and showed the following trend: hard maple (Acer sp.) > China fir (Cunninghamia lanceolata) > Japanese cedar (Cryptomeria japonica D. Don).Part of this report was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997. 相似文献
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Nowadays,IAQ(Indoor Air Quality) becomes a topic of general interest.This paper discusses the definition and influencing factors of IAQ and puts forward some measures for improving indoor air quality. 相似文献
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