Effect of density of riparian vegetation on effective tractive force

This study aims to clarify the effect of density of riparian vegetation on effective tractive force for various bedload transport conditions. Hydraulic model experiments were performed using a straight channel, and the methods used to calculate the effective tractive force necessary for estimating bedload transport rate in channels with riparian vegetation were studied. An apparatus was developed to directly measure the effective tractive force in a channel with riparian vegetation. Applying the apparatus in a hydraulic experiment allowed accurate direct measurement of effective tractive force, formerly estimated indirectly. Based on the experimental results, the effect of the density of vegetation on the effective tractive force was examined. Then the methods for estimating effective tractive force and bedload transport rate were studied. As a result of the experiment, it was found that the coefficient of velocity U/U_* and the ratio of coefficient of velocity (U/U_*)/(U/U_*) are negatively correlated with the density of vegetation. A very high negative correlation was also obtained between recession coefficient of effective tractive force ( = effective tractive force of a flow with riparian vegetation/effective tractive force of a flow with no riparian vegetation) and the density of vegetation. The friction factor of the channel bed f was positively correlated with the density of vegetation. Methods were presented for accurately estimating effective tractive force using equations including the relationships of the density of vegetation to the coefficient of velocity, the ratio of the coefficient of velocity, and the recession coefficient of effective tractive force. Using the estimated effective tractive force and an existing bedload equation enabled very accurate calculation of bedload transport rate in flows through riparian vegetation. The methods presented in this study have potential to be developed as a tool that can provide guidance in the planning and designing of riparian vegetation that are intended for the prevention and mitigation of floods and resultant sediment transportation.     

框锯减振机构平衡的研究

用变角速度减振机构平衡框锯往复惯性力研究表明，此方法可以有效地平衡往 复惯性力的９９％，使框锯的最大往复惯性力降低２６８倍；比飞轮平衡块法降低惯性力小９０倍。为框锯消除有害的冲击振动提供了理论依据。     

FIRE-EXTINGUISHING MECHANISM AND ENERGY PROCEDURE BY HIGH VELOCITY AIRFLOW

Thetechnology'ofextinguishingfircwithhighvelocity'aimow(usingwind-forcetoputoutfire)wasusedwidelydchngrecentyearsinChina.However.itisnotsuitabletoextin-gulshthlckbushortrunkfireinintensivebam-ingdegree.ThispaPerhasadiscussiononthemechanismandthccncrgr'procedurcinextin-guishingfirewithhighvelocityaiffiow.MATERIALSANDMETHODSTestmaterialistheabso1utewtwoodchipoflarch.Thelengthiso.5-l.5nunandareaISl.()-4.()cm'.Thetestmaterlalwasplacedonthecon1bustionbed'well-distributedly,withaloadof2.()…     

带锯切削速度及进料速度与锯材表面粗糙度的关系

本试验对锯材试件表面粗糙度进行了检量,依此反映带锯切削长度相进料速度不同时对材面质量的影响.冻材表面粗糙度值明显小于暖材的值,表面粗糙度值不受齿尖强化的影响.     

Difference in uprooting resistance among coniferous species planted in soils of volcanic origin

Uprooting resistance against wind force for coniferous plantations in soils of volcanic origin was studied. The difference in uprooting resistance among Abies sachalinensis, Picea jezoensis, and Larix kaempferi was discussed. The sample site was set in Chitose plantations in Hokkaido Japan, where typhoon 0418 caused fatal uprooting damage in 2004. An uproot resistance index—the ratio of the geometrical moment of area for uprooted root-plate to the moment susceptibility to wind force—was defined to quantify relative uprooting resistance against wind force. It was calculated from the dimensional measurements for the tree forms and root-plates of 100 uprooted sample trees after the typhoon attack. As a result, the uprooting resistance for Picea jezoensis, which was less damaged among the sample species, was estimated to be greater than those for the other two species.     

高得率浆废水冷冻结晶处理研究

冷冻结晶具有腐蚀小、能耗低、对挥发性有恶臭废水特别适合、回收水质量高等优点。试验对化机浆总废水及预测浸渍浓废水进行研究，结果表明：净化效果良好，废水色度、总固形物及ＣＯＤｃｒ可分别去除９２％～９３％、８３％～８６％及８８％～９１％，回收水可循环回用，浓废水可再浓缩燃烧，以确保工厂达到零排放操作。     

我国南方冬季和夏季肉牛体感温度研究

针对我国南方夏季炎热和冬季阴冷潮湿的气候特点,得到此环境气候下的肉牛体感温度公式,并以此指导实际生产。选取6头15月龄西门塔尔牛,测定其环境干球温度(DBT)、湿球温度(WBT)和风速(V)及其皮温。结果表明:干湿球温度与皮温呈正相关(冬季:rd=0.92,P0.01;rw=0.86,P0.01;夏季:rd=0.75,P0.01;rw=0.60,P0.01)。在我国南方冬季气候环境下,肉牛的体感温度公式为ET=0.81DBT+0.19WBT-2.99V(r=0.87,P0.001);夏季体感温度公式为ET=0.28DBT+0.72WBT-1.93V(r=0.93,P0.001)。     

苹果汁超滤的操作参数及质量研究

作者用美国KOCH膜系统公司提供的管式超滤膜组件,组装一套中试设备。对苹果汁的澄清作了试验研究。研究了主流液速度,平均压力,物料温度及物料固形物浓度,分别对渗透流速的影响以及主流速度,平均操作压力和温度共同对渗透流速的影响。并分析了澄清汁的质量。研究结果表明,对渗透流速的影响效果依次为压力,主流液速度和温度。在可能的情况下,应尽量选择大的压力和主流液速度。超滤的苹果汁的质量大大提高,有冷杀菌效果。     

接种根瘤菌和腐殖酸肥处理下的土壤风蚀效应分析

土壤风蚀是中国北方农牧交错带土地退化的主要原因之一。微生物和腐殖酸都能够改变土壤物理性质，可作为抗风蚀的材料有效利用，其抗风蚀效果和经济效果与其他方法有很大的不同。在此基础上通过风洞实验探讨微生物（接种根留菌）处理下和施用腐殖酸肥处理下抗风蚀效应，以及不同处理下的风蚀量对比。从结果分析得出，一方面，通过接种根瘤菌和施用腐殖酸肥料，改良土壤结构来抗风蚀，效果明显。技术易于推广．且成本较低（相对于PAM），另一方面它们能增加土壤肥力．带来经济效益。     

坡面细沟流侵蚀临界条件研究

从适用于陡坡的水动力学模型出发,研究坡面水流细沟侵蚀临界状态的判断方法。讨论了坡长、坡度、坡面投影长对细沟侵蚀的影响,采用临界摩阻流速随坡度变化、临界摩阻流速不随坡度改变两种假定分别进行模拟计算,以摩阻流速作为判别坡面细沟流侵蚀临界状态的水动力学指标,在给定的坡面尺寸、净雨强和初始微地形条件下,计算得出了细沟流摩阻流速达到临界值时所对应的坡度。