共查询到14条相似文献,搜索用时 687 毫秒
1.
2.
3.
4.
为建立土壤表层孔隙率与表面粗糙程度之间的关系,提出了一种采用立体表面积对土壤表面粗糙性状进行覆盖的分形分析方法.该方法结合地面激光扫描仪快速测得的地表原始不平度数据,可直接测定出土壤表面分维值D∈[2,3).为进一步探讨地表粗糙的细节信息,将立体表面积法引入到多重分形分析中,计算了各多重分形的谱参数.分析结果表明,单一分形维数Dl、Dr,多重分形谱参数α|fmax、△α均能够有效地反映地表粗糙程度,在忽略耕作方式影响的前提下,α|fmax与表层土壤孔隙率的线性相关性最高(R2=0.7014).因此利用土壤表层粗糙程度的分形参数进行土壤表层孔隙率的预测是可行的. 相似文献
5.
6.
7.
为了研究吊杯式移栽机作业时所栽植土壤的地表不平度,采用超声波测距传感器,对吊杯式移栽机作业时的土壤表面不平度进行了测量分析。将超声波测距传感器垂直于地面安装到移栽机上,连续测量地表高低的变化,采用Lab VIEW编程控制超声波传感器的参数设定,由NI USB-6343 X系列数据采集卡采集数据,并可实时显示和存储在笔记本电脑上。计算分析所测数据,得出了试验田地土壤表面不平度的一些参数值,即地表不平度的RMS高度、轮廓微观不平度的平均间距和分形维数,为研究土壤特性对吊杯式移栽机性能的影响提供了一定的基础数据。 相似文献
8.
耕作土壤地表不平度对拖拉机悬挂机组作业质量与作业效率有着重要的影响。为实现准确、高效的测量耕作土壤地表不平度,利用激光位移传感器设计了一套非接触式耕作土壤地表三维形貌测量装置,可获得区域内耕作地表的三维形貌图,并计算出地表不平度。该测量装置主要包括运动测试台、控制箱和基于Lab VIEW软件的数据采集系统,测量范围为1m×1m,空间分辨率为0. 001mm,距离分辨率为1mm。实验表明:测量装置的均方根误差为0. 017mm,表明该测量装置能够准确、高效地测量耕作土壤地表三维形貌,为后续耕作土壤地表三维形貌的理论分析与耕作土壤地表不平度评价提供了有效的支持。 相似文献
9.
耕作土壤表面不平度分析 总被引:5,自引:3,他引:5
利用激光式不平度测试仪测定犁耕耕地地面、圆盘耙耙地地面和驱动耙耙地地面的不平度,测定地面不平度沿着3个方向进行,即平行、倾斜和垂直于耕作方向。对每一种地面不平度的RMS高度、自相关长度和自相关函数进行了分析,结果表明:对于短的地块,可用单一尺度来表征地表不平度的特征,地表不平度特征属于指数相关函数,RMS高度和自相关长度具有明显的相关性;对于长的地块,平整的农业地表不平度具有分形性或多尺度性,其自相关函数是一种分形过程。 相似文献
10.
活塞销表面分形维数与传统参数模糊逻辑关系 总被引:1,自引:1,他引:0
用表面轮廓仪测量磨削加工的活塞销轴,得到各试件粗糙轮廓算术平均偏差、轮廓微观不平度平均间距数值。采用功率谱密度法计算各轮廓的分形维数,应用模糊数学理论,求出分形维数与高度及间距参数的模糊逻辑关系。该方法可望用于磨削加工表面的微观几何形状误差的识别与分类。 相似文献
11.
12.
施加生物质炭对盐渍土土壤结构和水力特性的影响 总被引:7,自引:0,他引:7
以江苏省沿海围垦区盐渍土为研究对象,基于Micro-CT图像扫描技术,分析施加生物质炭后改良盐渍土土壤孔隙度、土壤水分特征曲线以及非饱和导水率等土壤特性的变化,并建立分形模型预测土壤水力性质,以此揭示施用生物质炭对于海涂围垦区盐渍土土壤结构和水力特性的影响。试验设置0、2%、5%(与表层0~20 cm土壤质量比) 3个生物质炭添加水平,重复3次。结果表明:施加5%生物质炭显著降低盐渍土土壤容重,增加土壤总孔隙度和大孔隙度;大于0. 25 mm水稳性团聚体质量分数显著增加,增加土壤孔隙分形维数;提高土壤饱和含水率和饱和导水率;结合Micro-CT图像扫描技术和孔隙分形理论预测改良盐渍土土壤水分特征曲线和非饱和导水率,预测效果精度高,能够用于实际问题的研究。 相似文献
13.
14.
A. M. Abu-Awwad 《Irrigation Science》1998,18(2):101-107
A field experiment was conducted during the 1996/1997 season at the University of Jordan Research Station near Al-Muwaqqar
village to investigate the effects of sand columns, sand column spacing, soil ridges, and supplemental irrigation on soil
water storage, redistribution, and barley yields. The experimental site represents a typical Jordanian arid environmental
soil suffering from surface crust formation overlaying impermeable material. In the 600-mm-depth soil profile, soil water
storage was improved significantly by 59%, 45%, and 38% in the 1-m, 2-m, and 3-m sand column spacing treatments, respectively,
compared with soil water storage in the control treatment (no sand columns). Sand columns increased the moisture stored in
all four soil layers (0–150, 150–300, 300–450, and 450–600 mm). Moisture stored in the 450–600 mm soil layer increased significantly
by about 188%, 147%, 88%, and 29% in the 1-m, 2-m, 3-m, and 4-m sand column spacing treatments, respectively, compared with
moisture stored in the same soil layer of the control treatment. Increasing soil water storage also increased barley consumptive
use significantly from 130 mm in the control treatment to an average of about 185 mm in sand column treatments. Without supplemental
irrigation, barley grain and straw yields were negligible and almost zero. Barley yields in the control treatment, with 167
mm supplemental irrigation were low, being 0.19 ton/ha and 1.09 ton/ha of barley grain and straw, respectively. Sand columns
increased barley grain and straw yields significantly compared with the control treatment to a maximum of 0.68 ton/ha and
3.97 ton/ha, respectively, with the 1-m sand column spacing. Soil ridges perpendicular to the land slope had no significant
effect on increasing soil water storage due to lateral runoff and loss along the ridge. In general, sand columns minimize
surface runoff and evaporation by allowing water to infiltration through the strong surface crust. Sand columns act as a sink
for surface water, enhance subsurface lateral water movement, and reduce the possibility of surface crust formation in the
vicinity of the sand column opening by preventing surface ponding.
Received: 3 October 1997 相似文献