无耕地,landless
1)landless[英]['l?ndl?s][美]['l?ndl?s]无耕地
2)non-effective coefficient of cultivated land无效耕地系数
1.Results show that the non-effective coefficient of cultivated land is 6.结果表明:县内平耕地的无效耕地系数平均为6。
3)The new law does not refer to land used for farming.新法与耕地无关。
4)Cultivated land耕地
1.Ecological environment evaluation of cultivated land in coastal intensive agricultural areas by GIS;基于GIS的滨海集约农区耕地生态环境评价研究
2.To enhance the productive capacity of cultivated land and secure grain safety;提高耕地综合生产能力 保证粮食安全
英文短句/例句

1.A field located near a farmhouse.耕地农舍周围的耕地
2.Land fit to be cultivated.可耕地适于耕种的土地
3.arable land with good potential for rehabilitation具良好复耕潜力的耕地
4.CHAPTER FOUR PROTECTION OF CULTIVATED LAND             第四章 耕地保护
5.A piece of land, ie for farming or building on一块地(耕地或建筑用地)
6.5. Keep a balance between cultivated land occupied and cultivated land developed and reclaimed.(五)占用耕地与开发复垦耕地相平衡。
7.The father added: "Tomorrow, we are going to plough the field. Who is going to plough?"父亲又说:“明天我们要耕地,谁想耕地呢?”
8.Comparison of the Ploughland System and Scale Operation of Ploughland between China and Western Countries;耕地制度与耕地规模经营之中西比较
9.Strengthen Examination of Cultivated Land Replenishment to Secure a Balance Between Land Requisition and Compensation;加强补充耕地审查 确保耕地占补平衡
10.A Study of population stress simulation in slope cropland de-farming based on grid;基于GRID的坡耕地退耕压力模型研究
11.DIFFICULTIES AND STRATEGIES FOR THE DE-FARMING OF STEEP CROPLAND IN THE UPPER REACHES OF THE YANGTZE RIVER;长江上游陡坡耕地退耕的难点与对策
12.Article 31 The State protects the cultivated land and strictly controls the conversion of cultivated land into non-cultivated land.第三十一条 国家保护耕地,严格控制耕地转为非耕地
13.Resarch of space structure of the traits and deman of cuctivated land in Hunand Province;湖南省耕地特征与耕地需求的地域差异研究
14.Studies on the Carrying Capacity of Cultivated Land in Henan Province Based on the Cultivated Land Fertility;基于耕地地力的河南省耕地承载力研究
15.Characteristics of Soil Fertility and Evaluation of Land Capability in Plowland of Anhua County安化县耕地土壤肥力特征及耕地地力评价研究
16.Second, we have a large population but not enough arable land.第二条是人口多,耕地少。
17.He farms 100 acres of land.他耕种100 英亩地。
18.An unplowed strip of land.未犁之地土地的未耕带
相关短句/例句

non-effective coefficient of cultivated land无效耕地系数
1.Results show that the non-effective coefficient of cultivated land is 6.结果表明:县内平耕地的无效耕地系数平均为6。
3)The new law does not refer to land used for farming.新法与耕地无关。
4)Cultivated land耕地
1.Ecological environment evaluation of cultivated land in coastal intensive agricultural areas by GIS;基于GIS的滨海集约农区耕地生态环境评价研究
2.To enhance the productive capacity of cultivated land and secure grain safety;提高耕地综合生产能力 保证粮食安全
5)cropland[英]['kr?pl?nd][美]['krɑp,l?nd]耕地
1.Evaluation on heavy metal pollution of cropland in Zhangzhou;漳州市耕地重金属污染评价
2.Study on spatial variation of cropland value in Fujian based on GIS;基于GIS技术的福建省耕地价值空间分异研究
3.Dynamic changes of cropland based on fractal theory and its driving forces in arid oasis;基于分形理论的干旱区绿洲耕地动态变化及驱动力研究
6)land-farming地耕
延伸阅读

阀门技术注重流量系数和气蚀系数阀门的流量系数和气蚀系数是阀的重要参数,这在先进工业国家生产的阀门资料中一般均能提供。我国生产的阀门基本上没有这方面资料,因为取得这方面的资料需要做实验才能提出,这是我国和世界先进水平的阀门差距的重要表现之一。3.1、阀门的流量系数
阀门的流量系数是衡量阀门流通能力的指标,流量系数值越大,说明流体流过阀门时的压力损失越小。
按KV值计算式
式中:KV—流量系数
Q—体积流量m3/h
ΔP—阀门的压力损失bar
P—流体密度kg/m3
3.2、阀门的气蚀系数
用气蚀系数δ值,来选定用作控制流量时,选择什么样的阀门结构型式。
式中:H1—阀后(出口)压
H2—大气压与其温度相对应的饱和蒸气压力之差m
ΔP—阀门前后的压差m
各种阀门由于构造不同,因此,允许的气蚀系数δ也不同。如图所示。如计算的气蚀系数大于容许气蚀系数,则说明可用,不会发生气蚀。如蝶阀容许气蚀系数为2.5,则:
如δ>2.5,则不会发生气蚀。
当2.5>δ>1.5时,会发生轻微气蚀。
δ<1.5时,产生振动。
δ<0.5的情况继续使用时,则会损伤阀门和下游配管。
阀门的基本特性曲线和操作特性曲线,对阀门在什么时候发生气蚀是看不出来的,更指不出来在那个点上达到操作极限。通过上述计算则一目了然。所以产生气蚀,是因为液体加速流动过程中通过一段渐缩断面时,部分液体气化,产生的气泡随后在阀后开阔断面炸裂,其表现有三:
(1)发生噪声
(2)振动(严重时可造成基础和相关构筑物的破坏,产生疲劳断裂)
(3)对材料的破坏(对阀体和管道产生侵蚀)
再从上述计算中,不难看出产生气蚀和阀后压强H1有极大关系,加大H1显然会使情况改变,改善方法:
a.把阀门安装在管道较低点。
b.在阀门后管道上装孔板增加阻力。
c.阀门出口开放,直接蓄水池,使气泡炸裂的空间增大,气蚀减小。
综合上述四个方面的分析、探讨,归纳起来对闸阀、蝶阀主要特点和参数列表便于选用。两个重要参数在阀门运用中 。