基于热流逸效应的串联式气体分离系统设计

利用热流逸效应分离气体是一种在机理和应用模式上与传统分离方法完全不同的新颖方法。本文提出了一种由模块化热流逸式气体分离单元串联而成的气体分离系统,建立了描述其气体分离过程及关于其优化设计的数学模型,并开发了相应算法。以此为基础设计了热流逸式焦炉煤气分离制氢系统并解析其系统结构、部件和运行工况参数;该系统通过6级气体分离单元串联即可分离出纯度达99%以上的氢气,且其部件的制造及装配均可基于现有技术实现。在满足分离纯度要求的前提下,该系统能耗约为45.41kJ/m³,其优势在于可直接利用低品位热能驱动,符合能量梯级利用原则,从用能角度看也具有一定竞争力。基于热流逸效应的气体分离新技术具有鲜明特点,值得深入研究并在实践中尝试。     

基层林业站档案管理和统计工作中存在的问题和对策

基层林业站在工作的过程中会进行档案的管理以及统计工作,文章对当前林业档案管理和统计工作中存在的问题进行了分析和探究,通过分析和研究,为基层林业站的档案管理以及统计工作提供新的管理观念以及工作思路,并且提出了具体的解决对策。     

双向“锅盖效应”诱发戈壁荒漠长草机制分析

我国西北荒漠戈壁滩是气候干旱的不毛之地。然而，塔拉滩光伏电站建成后，场区内却出现了大面积长草的现象。本文探讨了光伏电站中野草生长的可能水分来源。从定性的角度初步探究了双向“锅盖效应”的诱发机理。通过对比光伏板区与非光伏板区分析了浅层土壤3个测点、大气的温度和水分变化规律，以及对双向“锅盖效应”的年循环和日循环水分变化规律进行简单的定量分析。结果表明光伏发电板组件及地表硬化覆盖层综合因素诱发了双向“锅盖效应”；在夏季光伏板可显著降低土壤表层温度；冬、春季以正向“锅盖效应”为主，是维持浅层土壤野草存活的主要水分供给，年循环水分提升幅度约11%~20%；而夏、初秋季以反向“锅盖效应”为主，保证了野草每日水分需求变化在小范围内波动。本文的相关研究也可为荒漠治沙提供参考。     

碳素纤维草对小型封闭水体水质净化作用

利用碳素纤维生态草对小型封闭地表水体进行净化处理。结果表明:生态草遇水散开,巨大的比表面积有利于微生物附着生长,且挂膜过程用时较短,生物膜形态稳定;碳素纤维生态草对水质有一定的改善和保持作用,COD去除率达71%,但TN和TP的去除效果并不明显,水质总体上能够持续满足地表水环境Ⅳ类标准。     

The impact of Japanese knotweed on river discharge at the watershed scale in New Jersey,USA

Recently, New Jersey has experienced several droughts and declared several critical water shortage areas, spurring interest in reducing freshwater resource depletion. Japanese knotweed (Reynoutria japonica Houtt.) is an invasive plant species that may have a significant effect on stream water loss. In order to assess the impact of this species on river-level water flow, we estimated total knotweed distribution along two tributaries of the Passaic River in New Jersey, USA using a combination of field measurements and GIS to calculate total daily water loss to the atmosphere from three stands of knotweed along these rivers. We measured total leaf area of each stand and transpiration rates across each stand from sun-up to sun-down. The average water loss was 8.5 L wate/day/m² of ground area covered in knotweed. Knowing the total distribution of knotweed along each river, the amount of river length covered by knotweed stands and the total water lost to the atmosphere per amount of knotweed along each river we were able to estimate the total amount of water transpired to the atmosphere by knotweed per river on a daily basis during its growing season. These results were compared to summer low flow rates to assess the impact on river flow during the growing season for Japanese knotweed. Our results suggest that knotweed along these rivers is reducing total flow by an average of 8% (approximately 800,000–1,400,000 L/day) during the summer months. This is important as the impact of invasive species on water resources in temperate areas is currently under-studied in ecohydrology.     

冷季型草坪草在信阳地区生态适应性研究

信阳农专植物科学系自1993年以来，先后从国外引进冷季型菖平草种5大类，35个品种，通过生态适应性研究，筛出适合信阳生态条件的冷季型草坪草品种16个，并已在信阳地区应用推广。     

基于粒子群优化算法优化反向传播神经网络构建冷藏草鱼新鲜度的近红外光谱预测模型

目的 构建基于各种机器学习算法结合近红外光谱的模型，从而确定出更准确预测冷藏草鱼新鲜度的方法。方法 采集连续冷藏6 d的草鱼片的新鲜度指标, 并进行方差分析。选择受冷藏天数影响最大的指标: 总挥发性盐基氮(Total volatile basic nitrogen, TVB-N)进行定量预测。运用x-y距离结合的样本划分(sample set partitioning based on joint x-y distance, SPXY)方法进行数据集的划分, 并采用正交信号校正法(orthogonal signal correction, OSC)、Savitzky-Golay (SG)、一阶导数及其组合算法进行光谱预处理。再运用竞争性自适应重加权采样(competitive adaptive reweighted sampling, CARS)、连续投影算法(successive projections algorithm, SPA)、主成分分析(principal component analysis, PCA)对光谱变量进行选择和降维。最后结合偏最小二乘回归(partial least squares regression, PLSR)、反向传播神经网络(back propagation neural network, BPNN)和粒子群优化算法(particle swarm optimization, PSO)优化BP神经网络(PSO-BP)建立草鱼(Ctenopharyngodon idella)片新鲜度定量预测模型。结果 各线性和非线性模型均得到了良好的预测效果, 预测集相关系数均超过了0.95。PLSR表现较为稳定, BP神经网络虽提高了校正集预测性能, 但是预测集性能不如PLSR。PSO-BP既保证了校正集预测性能, 也提高了预测集性能。基于OSC+D1预处理和CARS变量选择后的PSO-BP模型性能最优(R2P=0.987, 预测集的均方根误差为0.108, 相对分析误差为7.778)。结论 基于PSO-BP算法和近红外光谱结合的定量预测模型, 可以很好的预测冷藏鱼肉的新鲜度指标。     

蛇舌草保健饮料的研制

本文研究了以蛇舌草为原料生产蛇舌草汁保健饮料的工艺流程及工艺条件，确定了最佳工艺为：首先用80℃热水浸提30分钟，然后煮沸3分钟，粗滤后用离心机在1500转/分下离心5分钟，过滤后的滤液经调配后采用121℃，30秒的超高温瞬时杀菌。     

An impact of heat and mass transpiration on magnetohydrodynamic viscoelastic fluid past a permeable stretching/shrinking sheet

The present paper investigates analytically a continuous stream of viscoelastic fluid and magnetohydrodynamic flow of second-grade fluids owing to protracted sheets in a permeable medium with the help of the Cattaneo–Christov pattern. This idea is a new generalization of the classical Fourier law. Also, in this analysis, heat as well as mass transfer in second-grade fluid past wall suction/injection is assumed. A few similarity transformations are used to simplify the addressing of boundary layer expressions. An analytical solution is obtained by applying the Appell hypergeometric properties. Furthermore, our work also describes an effect of the relaxation time variable, elasticity number, and Prandtl number together with temperature fields. Also, we studied the newly introduced parameter, that is, the thermal radiation parameter by Cattaneo, over a Fourier heat flux pattern. In addition, some physical presentation of the measurements is illustrated in the graphs.