循环流化床烟气脱硫过程特性分析

在分析循环流化床气相和颗粒相流动特性以及浆滴蒸发和SO2吸收特性基础上，建立了循环流化床烟气脱硫过程特性的数学模型，考察动力学参数、热力学参数以及化学参数对脱硫效果的影响．结果表明，烟气出口温度与绝热饱和温度之差(ASAT)和浆滴蒸发时间是影响脱硫效果的重要参数，浆滴蒸发时间越长，有效反应时间越长，脱硫效果越好，而ASAT减小可延长浆滴蒸发时间．动力学、热力学和化学参数对脱硫效果的影响都可归结为改变浆滴的蒸发时间(或ASAT)．模型计算结果与已有实验结果吻合良好．     

环形内肋片圆管层流脉冲流动强化对流换热数值分析

为了解环形内肋片圆管中脉冲流动强化对流换热的机理,该文对这一现象进行了数值研究。数值计算结果表明:与具有相同Rem时的稳定流动相比,脉冲流动可使对流换热强化一倍以上,其强化效果与振荡频率、肋片高度和肋片间距有关;最佳量纲1振荡频率在400到1000之间,并随着Rem的增大而增加;对流换热强化的原因在于脉冲流动使由肋片引起的涡旋更加激烈,速度场和温度梯度场之间的协同性更好。     

富水氢氧化铝污泥冷冻时间的预测

对描述平板状和圆柱状富水氢氧化铝污泥冷冻的一维非稳态热传导数学模型进行适当的参数简化,并结合修正的Plank表达式,用数值法和半经验法对平板状和圆柱状污泥的冷冻时间进行了预测.结果表明,数值法预测的冷冻时间和温度与实验测定值吻合良好,但此法较烦琐;半经验法预测的冷冻时间比实验值稍偏小,但此法较简便.根据预测结果可以得到,在冷冻环境为-15℃时,8mm厚的平板状或6mm圆柱状污泥从30℃冷冻到-5℃所需的冷冻时间均约为40min,这为冷冻装置工业设计提供了基本依据.     

Effects of pattern shape on adaptation of dLGN cell

Pattern adaptation is one of the fundamental sensory processes in the visual system. In this study, we compared pattern adaptation induced by two types of sinusoidal drifting grating in dLGN cells of cat. The two types of grating have the same parameters (e.g. spatial frequency,temporal frequency and contrast) except their pattern shapes,one of which is normal grating and the other annular grating.The results suggested that the annular grating elicited stronger response and stronger pattern adaptation than the normal grating. This is consistent with the adaptation and aftereffect to the two types of drifting gratings seen in psychology and may reflect the subcortical neural mechanism underlying these psychological phenomena.     

连续环状色谱分离果糖-葡萄糖工艺的模拟分析

用 73 2Ca2 型树脂为吸附剂 ,进行了果糖 -葡萄糖混合溶液的分离试验 .假定了相平衡关系、返混规律和相间传质机制不变的情况下 ,用果糖或葡萄糖色谱分离收集液的产率和分离度为目标函数 ,以进料浓度、进料液流量、冲洗液流量、床层高度和床层旋转速度等操作条件为变量进行估算 ,取得了一系列曲线和一些规律 ,可为连续环状色谱柱的工程放大提供参考依据     

Thawing and freezing processes of active layer in Wudaoliang region of Tibetan Plateau

The interaction between permafrost and atmosphere is accomplished through transfer of heat and moisture in the overlay active layer. Thus, the research on the thermal and hydrodynamics of active layer during the thawing and freezing processes was considered a key to revealing the heat and moisture exchanges between permafrost and atmosphere. The monitoring and research on active layer were conducted because permafrost occupies about two thirds of the total area of the Tibetan Plateau. Based on the analysis of the ground temperature data and soil moisture data of monitoring near the Wudaoliang region of the Tibetan Plateau, the thawing and freezing processes of active layer were divided into four stages, i.e. summer thawing stage (ST), autumn freezing stage (AF), winter cooling stage (WC) and spring warming stage (SW). Coupled heat and water flow is much more complicated in ST and AF, and more amount of water is migrating in these two stages. Heat is transferred mainly via conductive heat flow in the other two stages, and less water migrated. Four water migration and coupled heat flow processes were addressed for the thawing and freezing stages, which are water infiltration driven by gravity, moisture advection and distillation driven by temperature and osmotic gradients, water migration driven by capillarity and unfrozen water migration driven by temperature gradient. The water content near the permafrost table tends to increase after one thawing and freezing cycle, which is the main reason for the development of thick ground ice layer near permafrost table.     

黄瓜片冻结过程的数值计算及实验研究

在考虑热物性变化的条件下,用计算机模拟了黄瓜片的速冻过程,讨论了介质温度、传热系数和食品厚度对冻结时间的影响,并且与不考虑热物性变化的情况进行了比较。结果显示,考虑了热物性变化的计算结果更接近实验数据。     

预处理和速冻贮藏对马铃薯片质构特性的影响

质地特性是评估冻制马铃薯片质量优劣的重要指标。本文研究了漂烫、速冻和玻璃化贮藏对马铃薯片质地特性和细菌结构的影响,发现６５℃漂烫３ｍｉｎ对马铃薯片质地影响较小,其细胞结构保持较完好;速冻过程会大幅度地降低马铃薯片的质地,其细胞结构受损严重;在玻璃化温度以下（－２５℃）贮藏的马铃薯片地质地有小幅下降,其细胞结构也会进一步遭受破坏,本实验发现速冻过程是引起冻制马铃薯片质地下降的主要原因,在速冻和贮藏过     

大间隙环流中Jeffcott转子系统失稳阈的研究

采用 Routh- Hurwitz稳定性准则 ,研究了大间隙环流中 Jeffcott转子系统的失稳阈 .结果表明 :大间隙环流对 Jeffcott转子系统的失稳阈有较大的影响 ,大间隙环流产生的流体动力质量 ma 是导致这种影响的根本原因     

冻结保存对黏附细胞超微结构的影响

黏附细胞的超微结构包括细胞骨架（cytoskeleton）、细胞黏附点（focal adhesion，FA）及细胞间连接（gap junction，GJ）．保持细胞超微结构的完整，对复温后细胞的存活率及细胞功能是至关重要的．实验发现，冻结到一196℃后，部分F肌动蛋白被切断、卷曲，且扩展面积与细胞成活率随温度降低呈现相似的下降趋势；冻结后蛋白质vinculin（FA）和Cx-43（GJ）的数量分别下降到对照组的22％及10％左右．综述了冻结过程对细胞超微结构影响的研究现状，分析了目前的研究所存在的问题与不足，提出了实时观察活细胞超微结构的方法，并给出了初步的结果．