预切种式木薯排种机构设计与试验

针对当前预切种式木薯播种器存在充种效果差、合格指数低的问题，该研究设计了一种由落种滑板、主动辊筒、型孔摩擦带、支撑辊组、从动辊筒及储种箱等组成的预切种式木薯型孔摩擦带式精密排种机构。阐述了排种机构的基本结构和工作原理。对关键部件参数进行设计，通过理论分析确定影响排种机构充种性能的主要因素为型孔摩擦带型孔形状、型孔数量、型孔摩擦带安装倾角、型孔摩擦带速度以及种茎层厚度。基于离散元法（discrete element method,DEM）建立种茎群-型孔摩擦带仿真模型，通过单因素仿真分析各因素对充种性能及种茎群规律的影响。以充种合格指数和漏充指数为评价指标，通过二次回归正交旋转组合仿真分析确定最优参数，利用Design-Expert数据软件，建立各试验因素与评价指标的数学回归模型，并进行参数优化。结果表明，影响充种合格指数和漏充指数的因素主次顺序为型孔摩擦带速度、型孔摩擦带安装倾角和种茎层厚度，圆整后的最优参数为型孔摩擦带速度0.6 m/s、型孔摩擦带安装倾角45°，种茎层厚度250 mm，此时的模型预测充种合格指数为94.63%，漏充指数为3.42%，重充指数为1.95%。在最优参数下...     

不同砂光量下展平竹板硬度及回弹率研究

竹材是粘弹性材料,在载荷条件下会产生弹性变形。以毛竹展平板材为研究对象,研究不同的竹材表面砂光量对其硬度以及卸载后对竹壁回弹率的影响。研究结果显示,随着展平竹板表面砂光量的增大,硬度先有上升的趋势,在砂光量为0.5 mm达最大值后逐渐降低;竹壁的回弹率随着表面砂光量的增大而逐渐降低,在砂光量为1.5 mm后下降趋势变缓;同时,竹壁的回弹率也随着卸载后陈放时间的延长而逐渐增大,但是增大趋势逐渐趋缓。     

试论农村金融改革

分析了我国农村金融运行的特征，论述了农村市场经济发展与农村金融支持体系的关系，提出了农村金融由集权金融向市场金融转化的思路，指出正规金融机构的改革，应建立转轨缓冲基金，将沉淀呆滞贷款独立出来。在此基础上，另起炉灶，建立责、权、利损相统一的体制，推行商业化改革。同时应对非正规金融机构进行扶持和规范。相应地，宏观调控也应转变为以间接调控为主     

围护结构特性对微型冷库降温性能影响的研究

围护结构对微型冷库造价及性能有着重要的影响。通过有限生命周期内微型冷库经济性能的分析，推导了微型冷库在使用年限不同时的经济保温层厚度计算公式。并在此基础上分析了围护结构的变化对微型冷库降温性能的影响，结果表明降温性能与围护结构的参数具有紧密的联系，而与库体容积的关系最小。     

Spatial variability of O layer thickness and humus forms under different pine beech–forest transformation stages in NE Germany

Spatial variability of humus layer (O layer) thicknesses can have important impacts upon soil water dynamics, nutrient storage and availability, as well as plant growth. The purpose of the present study was to elucidate the impact of forest‐transformation practices on the spatial variability of O layer thicknesses. The study focused on the Kahlenberg forest area (NE Germany) with stands of Scots pine (Pinus sylvestris) and European beech (Fagus sylvatica) of different age structures that form a transformation chronosequence from pure Scots pine stands towards pure European beech stands. Topsoil profiles including both, the O layer and the uppermost humic mineral soil horizon were excavated at intervals of 0.4 m along 15–20 m long transects, and spatial variability of O layer thicknesses was quantified by variogram analysis. The correlation lengths of total O layer thickness increased in the sequence consisting of pure pine stand (3.1 m) → older mixed stand (3.7 m) → pure beech stand (4.5 m), with the exception of the younger mixed stand, for which no correlation lengths of total O layer thickness could be determined. The degree of spatial correlation, i.e., the percentage of the total variance which can be described by variograms, was highest for the two monospecies stands, whereas this percentage was distinctly lower for the two mixed stands. A similar minimum for the two mixed stands was observed for the correlation lengths of the Oh horizon. These results suggest that the spatial structures of forest‐transformation stands may be interpreted in terms of a disturbance (in the form of the underplanting of beech trees). After this disturbance, the forest ecosystem requires at least 100 y to again reach relative equilibrium. These findings are in line with the results of other soil‐related investigations at these sites.     

柳杉木材密度测定研究

设定了长岭岗林场23年生柳杉人工林木材密度指标，分析立地条件对柳杉木材密度的影响，同时讨论了改善木材密度的方法。结果显示；立地条件对柳杉全干密度的影响差异显著，全干密度的差异主要是由土层厚度和土壤肥力的差异所导致。薄土陡坡及山脊上林木的气干密度和基本密度高于其它3种类型的密度指标。     

地方猪种对纤维饲料利用的研究Ⅰ.纤维饲料对生产性能和背膘厚度的影响

本试验以7％或14％的稻壳和18％或36％的米糠替代等比例玉米-豆饼基础饲粮中的玉米,研究纤维饲粮对30～80千克东北民猪(以下简称民猪)的生长及背膘厚度的影响。经研究表明饲粮稻谷副产品来源的NDF含量达到10％时,民猪的日增重明显受到影响,且随饲粮NDF的升高呈线性降低,干物质采食量随饲粮NDF的变化增加不明显,民猪消化能采食量略有下降,饲料效率随饲粮NDF的升高而变差。民猪生长慢的原因,除受其固有基因型支配外,采食量小是影响其增重的关键因素。提高饲粮NDF水平影响猪固有生长潜力的发挥。中、高NDF水平下,民猪的背膘较对照杂种猪薄,降低饲粮能量浓度可获得较瘦的胴体。     

传感技术在精确检测植物水分中的应用研究

将传感技术应用于植物水分的精确检测,从而达到节水的目的。其关键技术是研究可同时精确测量叶片厚度微变化和温度的双参数融合式传感器,测量叶片厚度微变化的传感器原理实验已经完成。     

单板厚度对杨木单板层积材强度性能的影响

单板厚度是影响单板层积材（英文缩写LVL）强度性能的主要因素之一，在同样的工艺条件下，单板越厚，LVL的剪断强度越低，剥离率越高。冷压胶合制造非结构单板积材时，建议采用4mm厚的单板     

Morphology of the pig cornea in normal conditions and after incubation in a perfusion apparatus

The fine structure of the pig cornea in normal conditions and after being used in a perfusion apparatus, for 4 h, is described. Earlier reports on the normal morphology of the pig cornea were partly not confirmed. Thus the number of cell layers in the epithelium was found to be 19-23 (a basal cell layer, 4–5 polyhedral cell layers and 14–17 squamous cell layers) compared to earlier reported 6–9 layers.The mean thickness of normal and perfused corneas were 722 μm and 752 μm respectively. Normal corneas had a hydration level of 77.2 % and after perfusion 78.5 %. The normal morphology and morphological changes due to exposure to perfusion were studied by light and electron microscopy. The differences observed between normal and perfused corneas have to be considered limited, and restricted mainly to the anterior squamous epithelium and the endothelium.Taken together our results indicate that the corneas used in the apparatus still had functional integrity.