共查询到19条相似文献,搜索用时 968 毫秒
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森林资源调查是合理组织森林经营,实现森林多功能永续利用、建立和健全各级森林资源管理的基本技术手段。其调查成果主要是以图件和统计表为表现形式。文章主要讲述了利用Microsoft Visual FoxPro进行成果数据库的逻辑检查、统计、汇总的整个过程,体现了该软件的简单易学,功能强大的特点。 相似文献
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介绍Delphi在Windows NT上的基于Client/Server结构的分布式数据访问,详细叙述了Client/Server模型的体系结构. Microsoft SQL Server关系数据库管理系统,最后介绍在Delphi中如何实现对SQL Server远程数据访问. 相似文献
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林地保护利用规划信息系统设计与开发 总被引:2,自引:1,他引:1
运用ArcGIS Engine技术和SQL Server空间数据库技术,构建林地保护利用规划信息系统,实现了林地数据动态存储和更新、统计报表、规划表图制作等功能,提高了林地保护利用规划的工作效率,为林地保护利用规划的管理和编制提供决策依据。 相似文献
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利用ARCGIS空间分析工具处理二类调查数据,得到昆楚高速(安宁段)公路两旁50m和500m的森林资源现状并生成相应小班和森林资源统计表,为安楚高速公路沿线绿化设计提供依据。 相似文献
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应用AutoCAD绘制林业用图时,一般都需要建立专门的林业制图线型库才能满足制图需要.作者在简单介绍制图中"线"的概念和类型的基础上,对线型的编辑和调用,林业制图线型库的建立方法、步骤进行了详细说明. 相似文献
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After a brief general account of natural conditions, the ninemain vegetation types available for afforestation since 1921are described separately. Preparation of the ground and plantingmethods are discussed, and this is followed by detailed noteson the relative local values of the species used, on the mainproblems of policy and management, and very briefly on the problemsof protection. The paper is illustrated by two charts whichare correlated. The first chart shows the main vegetation typesand their ground conditions and the second chart the same typesand the tree species which experience has found most satisfactoryfor planting thereon. There is in addition a table giving up-to-dategrowth data for the principal species used recently in afforestation. 相似文献
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This paper took the upper-lower wide belt sander B229 with four-feet wide belts, manufactured in China, as the study target.
By means of framework dynamic design, we study its vibration characteristics by commencing from the place having horizontal
defects and used experimental modal analysis (EMA) and power spectrum density (PSD) to observe the sanding parts and the whole
machine, respectively. In the modal test, we mainly adopted the cross spots testing method to get the frequency response function
of the fixed spots to every excitation vibration spot, then applied the SISO frequency response function and the frequency
response function fitting method to identify and complete parameter recognition, respectively. The typical frequency response
function chart of the whole machine and its sanding parts, as well as its second-order mode charts of contacting roller, were
obtained. Through PSD analysis, we can get the amplitude-frequency spectrum and drive frequency.
Translated from Scientia Silvae Sinicae, 2005, 41(6): 132–137 [译自: 林业科学] 相似文献
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国产人造板宽带砂光机功率谱密度和试验模态分析 总被引:3,自引:0,他引:3
以国产B229型四四砂架人造板双面宽带砂光机为研究对象,从易产生横纹缺陷入手,对其砂架部件、整机等分别采用试验模态分析(EMA)及功率谱密度法(PSD)来开展振动动态特性研究。在模态试验中,采取测量点固定、改变激振点的跑点测量方法,得到固定测量点对各激振点频响函数,并应用SISO频响函数识别法,通过频响函数曲线拟合来完成模态参数识别,获到典型的整机、砂架部件的频响函数图和接触辊的二阶振型图。通过PSD分析,获得砂光机的PSD图谱和激励频率等。 相似文献
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以图形几何实体为基础,将零件信息归类为原始输入信息和工序过程信息,提出了工序图逐步生成的设计方法.以直齿圆柱齿轮为研究对象,以AutoCAD为开发平台、DXF为开发接口、C语言为开发工具,成功地对实心齿轮和腹板式齿轮的工序图进行了参数化自动生成. 相似文献
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Kiln drying of timber sometimes makes use of air at well above 100 °C and at very high humidities. The psychometric charts
of Carrier and Mollier do not normally accommodate such air states and so they are not useful. Charts are given herein which
use the axes ln r and ln ps where r is the relative humidity and ps is the pressure of water vapour at saturation. Such charts accommodate the above conditions without difficulty and fit tidily
onto a rectangular sheet. The values of ps are not shown but they are expressed as a function of dry-bulb temperature, which is shown on the charts. Charts are given
for normal and high temperature ranges, and to display different properties we have chosen to use separate charts rather than
to fit too much information on a single chart.
Received 8 May 2000 相似文献
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建立了移动集中力作用下悬索的非线性方程.指出了移动集中力对悬索的影响相当于强迫激励.当移动集中力运动速度与悬索横向弹性波速度一致时.系统将发生主共振.通过多尺度法求解.得到了主共振时各阶分叉点.通过效值计算,得到了分叉图. 相似文献
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森林生态具有价值并且可以计量。本文利用贵州水土保持林价值计算模型中林龄和木材市场价格这两个相对变动的因素与价值之间的函数关系,编制了贵州水土保持林主要树种(类型)价值数表和数图。在为水土保持林价值动态变化进行直观、形象显示的同时,更能为贵州水土保持林在今后的评估、征占、置换、流转、转让等林业经济活动提供计量、计价的依据和标准。 相似文献