crown block

crown block的基本解释

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定滑轮

与crown block相关的网络例句 [注：此内容来源于网络，仅供参考]

The result pointed out that the vertical distribution of foliage for each species was different,however,generally speaking,the foliage in upper crown (0.3CL) for broad-leaved species in natural secondary forest took a small percentage,about 10%;in middle or middle lower of the crown(0.4CL to 0.8CL) the branches here took the majority percentage of whole foliage,almost 60%to 75%;but in lower crown(0.8CL),there was about 10%of whole foliage.(5)The interspecies competition of trees in secondary forest was expressed by Hegyi competitioin index,and the active competitor was calculated by the competition zone radius and the tree position,DBH,and distance in the zone,it was not all competitors in tranditional calculation.The study introduced crown area overlap index to describe the crown competition between subject tree and its competitors,furthermore,the crown area was classified into 5 levels with a method of equal crown projection area,therefor,the resulting crown area overlap index showed more realities of existing stand conditons.(6)Based on the theoretics of multiply divide,the spatial strcture optimizing model of secondary forest stand selective thinning was developed by diversity mingling,aggregation index,competition index and crown area overlap index,also designed 10 constraint conditions which were related to forestry meanings,the objective function was solved by the implicit enumeration method with LINGO 9.0,using 0-1 integer programming.

并且得出，每个树种在树冠内相对高度上的叶量的垂直分布是不同的，天然次生林阔叶树种的叶量在树冠的上部(0.3CL以下)所占比例很小，约占10%左右；在树冠的中部以及中下部(0.4CL～0.8CL)，叶量所占比例最大，几乎集中了整个树冠60%～75%的叶量；而在树冠的下部(0.8CL以下)，几乎占很少的叶量，大约10%左右。5、采用Hegyi竞争指数来表现次生林内林木的竞争关系，并且根据竞争圈的大小和林木在竞争圈内的分布位置、大小与距离来计算有效的竞争木，并不是传统意义上的全部竞争木；本研究提出用树冠叠加指数来表示林木与周围树木的树冠竞争情况，并采用等树冠投影面积法把树冠分为5级，这样计算的树冠叠加指数更加与现实林分相符。6、本研究基于乘除法的思想，用多样性混交度、聚集指数、竞争指数和树冠叠加指数构建了天然次生林择伐空间优化模型，设计了10个与林学意义相一致的约束条件，并采用0-1整数规划的思路，在LINGO9.0软件中使用了隐枚举法对目标函数求得最优解。7、以M702标准地为应用实例，具体计算出了每株采伐木，经过择伐后，目标函数值按模型设计的要求发生了极大的改变，增加了5倍多，说明了最后这个解的优良性，满足了设计的要求。

Branch diameter distributions changed from an abundance of small-diameter branches in the upper-crown, and in the middle-crown, composed with differential branch diameter, but only a few large-diameter branches in the lower-crown. Branch volume generally increased from upper- to lower-crown, and reached a maximum around the crown base. Branch density decreased from upper- to lower-crown.

枝条口径分布，从树冠上层多数的小径枝条至树冠中层转变为含不同口径枝条且变异较大，在树冠下层仅由少数大口径枝条组成；枝条体积则由树冠上层向下层增加，至树冠基部达最大值；而枝条密度则从树冠上层向下层逐渐递减。

The strike of Huanghai block and Huaihai block in the east mainly tends towards north-east, while the strike of Shanxi block and the eastern edge of Ordos block in the west mainly tends towards north-west.(3) According to the feature of Moho, the crust of the research zone can be divided into six parts in the Shanxi block, Moho looks like a nearly north-south sunk belt, and the crust is thick; at the southern edge of the Inner Mongolia block and in the south of Yanshan block, Moho presents the structural features of fold belt, tending nearly towards east-west; at the eastern edge of Ordos block, the structure of Moho is relatively complex with nearly northwest folds.

3根据莫霍面的形态特征，研究区地壳可大致划分为6个区块；在山西地块范围内，莫霍面呈近南北向的凹陷带，地壳厚度大；内蒙古地块南缘和燕山地块南部，莫霍面表现出褶皱带的构造特征，其延展趋势为近东西方向；鄂尔多斯地块东缘，莫霍面构造相对复杂，呈近北西向凸、凹相伴的褶皱；黄淮海地块为莫霍面隆坳区，隆、坳相间排列，构造较复杂，但从整体上看，这是全区莫霍面最浅的隆起区段；鲁西台背斜主要为莫霍面断陷区，其断陷带沿枣庄－曲阜一线向北西方向延伸。

与crown block相关的网络解释 [注：此内容来源于网络，仅供参考]

crown block dismounting：放天车

起天车 crown block hoisting | 放天车 crown block dismounting | 高空作业手 erector work high above round

Crown Block：天车

Swivel 水龙头 | Crown Block 天车 | Traveling Block 游车

Crown Block：定滑轮

Christmas tree 采油树 | crown block 定滑轮 | travelling block 动滑轮

Crown Block：起重定滑轮

crown bit 活头钎子 | crown block 起重定滑轮 | crown drill 活头钎子

Crown Block：拱顶石

crown 冠顶 | crown block 拱顶石 | crown hinge 拱顶铰