共查询到20条相似文献，搜索用时 62 毫秒
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The construction and function of high temperature melt viscosity test instrument are introduced in this paper. And the character of temperature control system is given. In order to improve dynamic and static performance of the temperature control system, a new method is proposed which combines threshold control with adaptive fuzzy PID control. While the current temperature of the heating furnace is much lower than the given temperature, threshold control works in order to protect system and improve dynamic performance. When the current temperature is close to the given value, adaptive fuzzy PID control works to improve static performance. At last, simulation and experiment results validate the proposed control method. 相似文献
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为解决冬春季温室育苗环境温度低的问题,设计基于碳晶电热膜的温室育苗保温加温系统,并于冬季最冷时段在河北省永清县的连栋玻璃温室内对系统的保温加温性能进行实际测试。以无加温育苗试验区作为对照,研究分析碳晶电热膜根区加温对基质温度和空气温度的影响,探讨苗床上保温覆盖的保温作用和加温的均匀性。结果表明,单层膜保温覆盖可使加温育苗区内空气平均温度值较温室内高1℃;碳晶电热膜加温可使基质温度平均值及最低值提高7.3℃和10.7℃;基质温度最低值偏离度为2.9%,平均值为6.1%。基于碳晶电热膜的温室育苗保温加温系统可有效提高育苗环境温度且加温均匀性高,为培育高质量种苗提供有力保障。 相似文献
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CCD radiation temperature measurement method for hot continuous casting billet surface 总被引：2，自引：0，他引：2
According to the present research status and existing problems of hot continuous billet surface temperature non contact measurement technology, a real time temperature measurement model, which combines two-color(R,G) and monochrome (B) of surface radiation image, is established. The surface image is collected through tricolor charge coupled device (CCD) sensor, at the same time, the temperature dynamic response range of CCD can be improved by controlling integrated time and setting different apertures. Through computer image process technology, multi-point temperature can be measured simultaneously, and 2-D temperature field distribution on continuous casting billet surface can be realized. It is be proved by theory and application that the model and method can provide a theory and technology support for realizing surface temperature field on-line measurement for continuous casting billet. 相似文献
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为研究西兰花种子萌发对不同温度的响应,以西兰花‘台绿1 号’为材料,在4~38℃温度区间进行种子萌发实验,结合Logistic 函数和积温模型公式计算种子萌发的最低温度、最适温度和积温。结果表明：西兰花‘台绿1 号’种子在16~32℃温度区间发芽率在93%以上,发芽率较高,而4、10℃低温条件下平均发芽时间最长,发芽势为0,38℃高温发芽率较低,低温和高温明显抑制西兰花种子萌发;西兰花‘台绿1 号’种子萌发适宜温度范围是20~32℃,最适温度为32℃,最低温度Tb为3.98℃;西兰花‘台绿1 号’种子累积萌发率达50%所需要的积温值是22.70℃·d;西兰花种子萌发时间t 可利用公式t=22.70/(T-3.98)进行预测（T代表萌发温度）。利用模型方法定量分析西兰花种子萌发对温度的需求是可行的。 相似文献
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基于布谷鸟搜索神经网络的微波加热温度预测模型 总被引：1，自引：0，他引：1
微波加热是一种与被加热物直接相互作用的选择性加热方式，具有清洁、节能、减排等特点。针对工业物料作为微波加热负载时，其温度非线性变化的特点，以微波工业加热过程中的多维、海量参数为研究对象，基于泛函接神经网络模型提取样本数据的深度特征，提出了一种基于布谷鸟搜索算法，优化BP神经网络的网络参数，建立了以"数据驱动"为手段微波加热工业物料温度模型。仿真实验结果证明了所提出模型的准确性、实时性。 相似文献
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The temperature field of sodium silicate bonded sand heating by microwave energy is measured and analyzed by the related characteristic quentities. The result shows that sodium silicate bonded sand heating by microwave energy has characters such as temperature rising speedy and heating occurring from inside to outside at the same time. The reasons of those characters are discussed by testing and analyzing. The viewpoint that the temperature rising of sodium silicate bonded sand heating by microwave energy is revocable by sodium silicate absorbing microwave energy is proposed. The results of this study are useful on rightly understanding the essentials of the heating by microwave energy for sodium silicate sand and rightly constituting heating technology. 相似文献
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本文使用太平洋286点海水温度资料,对我国粮食总产及其地理分布进行多时效的动态监测.为了能一次预报出整个的产量场,首先对初始场作自然正交展开,提取前P个主成分进行海温网格点的复相关计算,用以筛选因子组建预报方程.预报模式采用时效可任意指定的动态链接式,它可以通过海温这个“窗口”,实现对全国粮食总产前景的连续监测. 相似文献
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Numerical simulation of the flow and temperature fields in an automotive exhaust muffler 总被引：2，自引：0，他引：2
By building a model of a typical exhaust muffler structure, a grid mesh was formed based on the calculation characteristic of the flow field. The software ANSYS CFX then was used to numerically simulate the flow and temperature fields in a muffler. The effects of the gas velocity and temperature variation on sound elimination performance, including the acoustics and aerodynamics performance, were analyzed. The result suggests that high velocity turbulence and high speed flow should be eliminated from muffler structures when designed. At the same time, to provide satisfactory noise elimination, pressure loss should be reduced as far as possible. The pressure loss can be decreased when reducing the perforation structure. 相似文献
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本试验旨在研究加热回流法提取构树叶总黄酮的最优提取工艺。采用单因素试验设计研究加热回流法提取构树叶总黄酮的适宜反应时间、反应温度、液料比和乙醇浓度,上述4个因素均分别设置为5个水平,以总黄酮提取量为评价指标筛选最佳反应条件;在此基础上采用正交试验设计研究最优提取工艺,对筛选确定的最佳提取工艺进一步进行重复验证试验和工艺放大验证试验。结果表明：单因素试验筛选获得最佳乙醇浓度为70%,最佳反应时间为2.5 h,最佳料液比为1:30,最佳反应温度为70℃;正交试验确定加热回流法提取构树叶总黄酮的最优提取工艺为：乙醇浓度70%、反应时间2.5 h,料液比1:30,反应温度80℃;重复验证试验和工艺放大验证试验得率分别为23.11 mg/g和23.13 mg/g。本工艺稳定性和可操作性良好,适用于构树叶总黄酮的提取。 相似文献
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This paper analyzes the energy-efficiency of the measurable heating system through the analysis of three main energy-efficient measures:room temperature control,system climate equalizing and variable-flux circulation,based on the data of local climate;it points out that the remarkable energy-efficiency of the measurable heating system is gained especially in cases of the use of residential mode for the residence and office mode for the public building.Then,according to the analysis of energy-efficiency and market price of equipment added for this heating measure,the economy of the measurable heating system is analyzed.The results indicate that heating companies have gained extraordinary profits from new heating measure,the benefit for the clients are fulfilled only by setting reasonable heating prices and the measurable heating should be in accord with the market rules. 相似文献
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In order to enhance the heat transfer in the phase change heat storage device, a rectangular cavity filled with metal foam / paraffin wax is made. The melting heat storage experiment of foam metal / wax composite phase change material was carried out in the transverse wall temperature conditions. The temperature change curve is drawn according to different heating temperatures. Both the effects of natural convection in rectangular cavity on temperature distribution and the impact of heat transfer temperature difference on the thermal storage time are analyzed. The results show that the melting process of the paraffin in the body cavity is reinforced by the high thermal conductivity of copper foam. The remaining solid paraffin is accelerated to melt by the natural convection of the liquid paraffin formed near the heating surface; and the greater the heat transfer temperature difference is, the greater the natural convection is and the shorter the time for heat storage is. 相似文献
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豆浆加热程度对内酯凝胶强度的影响 总被引：1，自引：0，他引：1
研究豆浆在不同加热条件下对内酯豆腐凝胶强度和黏度的影响。在相同GDL浓度、保温温度及保温时间的条件下,生豆浆的加热温度及加热时间对内酯豆腐凝胶网络结构有着重要影响:生豆浆在温度95￣100℃加热10min,制得内酯豆腐的凝胶强度最好;生豆浆的加热温度在75℃以下时,无凝胶产生,只有絮状沉淀,且黏度随加热温度和加热时间的增加而增加。 相似文献
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以甜玉米为试材,通过对蒽酮浓度、蒽酮-糠醛显色反应温度和时间的探讨,研究优化蒽酮比色法测定甜玉米中可溶性糖含量的反应条件。结果表明,蒽酮比色法适宜的测定条件为:蒽酮的最佳浓度15 mg/mL,显色反应温度80℃,加热时间15 min。在此条件下葡萄糖标准品浓度与吸光度之间具有良好的线性关系(y=15.954 x+0.097 6,R2=0.999 2)。采用此优化条件测定甜玉米籽粒中可溶性糖含量,其测定结果具有良好的重复性(RSD为0.47%)和准确度(平均回收率为101.92%)。 相似文献
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It is worthwhile for saving energy and protecting environment to use conductive concrete as an indoor heating engineering material. Indoor temperature is the key concern of heating system. Based on convection, radiation and Joule effect, a method to calculate temperature of concrete and indoor air was presented. The method did not need to model the air, which simplified the preprocessing. The numerical result agreed with experiment satisfactorily, with a difference of 2.40%, which proved the correctness of the model. Numerical tests of different conditions showed that electrical resistivity with higher potential than power voltage and concrete thickness was the key to increase heating efficiency. 相似文献
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S. Narayanan P. V. V. Prasad A. K. Fritz D. L. Boyle B. S. Gill 《Journal of Agronomy and Crop Science》2015,201(3):206-218
High temperature is a major environmental factor that limits wheat (Triticum aestivum L.) productivity. Climate models predict greater increases in night‐time temperature than in daytime temperature. The objective of this research was to compare the effects of high daytime and high night‐time temperatures during anthesis on physiological (chlorophyll fluorescence, chlorophyll concentration, leaf level photosynthesis, and membrane damage), biochemical (reactive oxygen species (ROS) concentration and antioxidant capacity in leaves), growth and yield traits of wheat genotypes. Winter wheat genotypes (Ventnor and Karl 92) were grown at optimum temperatures (25/15 °C, maximum/minimum) until the onset of anthesis. Thereafter, plants were exposed to high night‐time (HN, 25/24 °C), high daytime (HD, 35/15 °C), high daytime and night‐time (HDN, 35/24 °C) or optimum temperatures for 7 days. Compared with optimum temperature, HN, HD and HDN increased ROS concentration and membrane damage and decreased antioxidant capacity, photochemical efficiency, leaf level photosynthesis, seed set, grain number and grain yield per spike. Impact of HN and HD was similar on all traits. Greater impact on seed set, grain number and grain yield per spike was observed at HDN compared with HN and HD. These results suggest that HN and HD during anthesis cause damage of a similar magnitude to winter wheat. 相似文献
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河蟹高温热害综合指数的构建及应用 总被引：2，自引：0，他引：2
根据河蟹养殖期间高温热害发生的主要特征,基于河蟹养殖高温指标和权重指数构建了河蟹高温热害指数模型,使用江苏高淳区固城湖河蟹养殖历史观测资料对模型参数确定,建立了日高温热害等级判别指标体系,系统分析了全省河蟹养殖高温热害发生规律和气候变化趋势。结果表明：河蟹养殖高温热害主要发生时段为6—8月（即江苏夏季）。河蟹高温热害指数随年际变化呈明显的“U”字型,第一高发期在20世纪60年代,第二高发期在21世纪前13年,第二高发期的发生频率和危害程度均高于第一高发期。主要易发区域是沿江和苏南地区,里下河地区相对较轻。为了科学防御高温热害的影响,建立了养殖水环境监测系统和高温热害气象预警服务系统,及时发布监测预警信息,通过调整水位、投饵量和时间等来减轻高温热害的影响,提高河蟹养殖经济效益。 相似文献
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对油脂碱炼过程中的水洗废水处理后,用于毛油的脱胶。通过单因素与正交试验,确定了最优脱胶工艺条件:碱炼水洗水添加量为油质量的10%,时间35 min,温度75℃,搅拌速度70 r/min,在此条件下,得到脱胶油的磷质量分数为9.6 mg/kg,脱胶油280℃加热试验合格。 相似文献