家用自动浇花机的设计

采用一种结构简单、使用方便灵活、用途广泛的多功能集成电路,即555时基集成电路。设计了家用自动浇花设备,用于实现水泵及电磁阀的开启与关闭自动控制．当土壤中的含水量低于设定值时该系统可进行灌溉,可以根据设计好的土壤湿度分别对多种花卉自动进行浇灌,实现家庭花卉种植自动浇水的功能．该设备具有重量轻,操作简单,使用方便,工作可靠,过载能力强,批量生产成本低,适合家用的特点．     

论《离散数学》学习方法

《离散数学》以研究离散量的结构和相互间的关系为主要目标,充分描述计算机科学的离散性特点,是计算机专业的专业基础课。正确掌握学习《离散数学》的方法对学生具有重要意义,应从《离散数学》的学习内容和学习方法等方面进行积极的探讨。     

Improving Nonlocal Means Method via a No-reference Image Content Metric for MRI Denoising

The patch matching of the traditional Nonlocal means （NLM） filter mainly depends on structure similarity and cannot adapt to the patch rotation or mirroring transformation. Therefore, designing a measure with rorationally invariant similarity is of significant importance for improving the effectiveness of patch comparison of NLM. This paper proposes to apply a no-reference image content metric with the rotation-invariance to NLM for denoising Magnetic resonance （MR） images. The metric measures quantitatively the content of a patch in an image, including sharpness, contrast, and geometric features such as textures and edges. The metric values for every patch are computed and added into the Gaussian matching kernel of NLM so as to effectively perform patch matching. The main advantage of the proposed method is that it does not need to rotate patches in different orientations during patch matching. Experimental results show that the proposed method is superior to the traditional NLM, the state-of-the-art method Block-matching and 3- D （BM3D） filtering and the Unbiased NLM （UNLM） for MRI denoislng.     

浅析配合料质量的影响因素

通过生产实践，对配合料质量影响因素作了具体分析。影响调合料质量因素诸多，但如果控制好几个环节，仍能制备出优质的配合料。从配合料质量的检测方法、取样代表性、影响配合料质量的机械设备、原料粒度、水分、加水温度等诸多方面对调合料质量的影响因素进行了深入分析，阐述了要配出优质的配合料必须要加强配合料均匀度的检测、各种设备的管理及配合料制备的工艺管理等。     

Development and validation of a coupled heat and mass transfer model for green roofs

This paper describes a dynamic model of transient heat and mass transfer across a green roof component. The thermal behavior of the green roof layers is modeled and coupled to the water balance in the substrate that is determined accounting for evapotranspiration. The water balance variations over time directly impact the physical properties of the substrate and the evapotranspiration intensity. This thermal and hydric model incorporates wind speed effects within the foliage through a new calculation of the resistance to heat and mass transfer within the leaf canopy. The developed model is validated with experimental data from a one-tenth-scale green roof located at the University of La Rochelle. A comparison between the numerical and the experimental results demonstrates the accuracy of the model for predicting the substrate temperature and water content variations. The heat and mass transfer mechanisms through green roofs are analyzed and explained using the modeled energy balances, and parametric studies of green roof behavior are presented. A surface temperature difference of up to 25 °C was found among green roofs with a dry growing medium or a saturated growing medium. Furthermore, the thermal inertia effects, which are usually simplified or neglected, are taken into account and shown to affect the temperature and flux results. This study highlights the importance of a coupled evapotranspiration process model for the accurate assessment of the passive cooling effect of green roofs.     

多年冻土地区路基温度场和水分迁移场耦合问题研究

基于冻土路基特殊的工程性质,对水分迁移结果即含水量变化对温度场的影响特别是对热物理参数的影响进行了研究,考虑温度变化对土体水分迁移机理及计算方法进行了研究,提出了冻土路基水热耦合计算模型,并给出了水热耦合计算的总体流程图,实例计算揭示了冻土路基温度场和含水状态的横向差异。     

油烧辊道窑预干燥带干燥过程微观数学模型的研究

本文分析了辊道窑内预干燥带传热及干燥过程的特点,引入Morgan的蒸发面后退模型,建立了陶瓷制品干燥过程中温度场分布及湿含量计算的微观数学模型。     

THERMAL ANALYSIS AND DRYING KINETICS OF OLIVE BAGASSE

ABSTRACT

The slow thermal decomposition of olive bagasse at temperatures ranging from 25 to 900° C, with particular stress on the moisture evaporation phenomena, is analyzed making use of thermogravimetry, derivative ihermogravimelry and differential scanning calorimetry. The results obtained demonstrate that Thermal Analysis techniques contribute for the characterization of iniernai moisture transfer processes. “ Drying curves” obtained from Thermal Analysis experiments were compared with thin-layer drying curves of olive bagasse at relatively high temperatures. The existence of a critical moisture content, which distinguishes two types of water liaisons, was demonstrated, and its value quantified at 17-18%.     

Effect of Pressure on Moisture Transfer During Moisture Adsorption

ABSTRACT

A set of coupled heat, mass, and pressure transfer equations was used to describe the moisture adsorption process in gmn kernels. The finite element method was used to solve the system of equations. The technique was applied to analyze the temperature, moisture, and pressure distribution in a barley kernel during soaking with steep water. The temperature and moisture distributions with (heat, mass, and pressure transfer model) and without (heat and mass uansfer) the effect of pressure were simulated for assumed conditions. The results obtained from the heat, mass, and pressure transfer model show a marked difference from the results obtained from the heat and mass transfer model. This indicated that a pressure gradient exists during the transfer Process, causing additional moisture movement due to filtration effect. Hence. the pressure tern cannot be assumed constant during the moisture adsorption process. The simulated temperature, moisture and pressure profiles and gradients can be used for determining the optimum time required for solking kernels with sleep water to produce barley malt.     

Dielectric Drying

ABSTRACT

Dielectric heating is a term which covers both radio frequency (RF) and microwave systems. It has been used for industrial drying for many years because it has a number of advantages over other drying processes. These advantages include the volumetric dissipation of energy throughout a product, and the ability to automatically level any moisture variation within it. It is generally true to say that these techniques can only be justified in processes involving material of “high” value being processed in modest quantities but when combination with other fuel fired techniques there may be opportunities to broaden the range of applications. In addition to a desciption of current industrial applications, the theory of dielectric heating, the similarities and differences between RF and microwave are discussed together the effects of the dielectric roperties of a product on the design of the equipment