期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
煤层气水平井开发生产规律研究
1
作者 邹学学 左银卿 +2 位作者 刘华 周叡 苗耀 《中国煤层气》 2016年第5期12-14,共3页
以沁水盆地煤层气田樊庄区块多分支水平井开发实践为基础,对煤层气水平井开发生产规律进行研究。本文首先分析水平井适应的地质条件,研究发现樊庄区块拉张区水平井产气能力最高,平衡应力区次之,而挤压区最差。然后通过生产数据统计分析... 以沁水盆地煤层气田樊庄区块多分支水平井开发实践为基础,对煤层气水平井开发生产规律进行研究。本文首先分析水平井适应的地质条件,研究发现樊庄区块拉张区水平井产气能力最高,平衡应力区次之,而挤压区最差。然后通过生产数据统计分析,认为煤层气水平井单位面积产水指数、采气速度两个开发指标与产气量存在较强的关联性,煤层气产气较高的水平井单位面积产水指数一般小于50,且其采气速度控制在5%左右。 展开更多
关键词 煤层气 应力 连通性 产水指数 采气速度
下载PDF
Phenotypic correlations of somatic and gonad traits of sea urchins Glyptocidaris crenularis in two sampled periods:first insight into its breeding and aquaculture 被引量:3
2
作者 罗世滨 田晓飞 +4 位作者 赵冲 周海森 张伟杰 封文萍 常亚青 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2014年第2期344-348,共5页
Prior knowledge of the correlations among commercially important traits in Glyptocidaris crenularis can be used to guide development of breeding and aquaculture programs for this species.We evaluated the phenotypic co... Prior knowledge of the correlations among commercially important traits in Glyptocidaris crenularis can be used to guide development of breeding and aquaculture programs for this species.We evaluated the phenotypic correlations between somatic and gonadal traits in G.crenularis during two sample periods(October 2010 and April 2011).The coeffi cients of variation(CV%)for body weight(BW),redness(a*),yellowness(b*),gonad wet weight(GW),and gonad index(GI)were>20% in both periods,while those of other traits were very low.GW was signifi cantly correlated with somatic traits(diameter,height,and body weight)in both periods,although the correlation coeffi cients ranged from 0.473 to 0.636(P<0.01).Gonad moisture content(GC),a*,and lightness(L*)were not signifi cantly correlated with somatic traits(P>0.05).The color trait b* was negatively correlated with somatic traits(test diameter,test height,and body weight)during the period when the gonads were well developed(April 2011,P<0.05).We observed little difference in the nature of the phenotypic correlations between the two sample periods.The high variation in the somatic and gonad weight traits in G.crenularis suggests there is considerable potential for selective breeding.However,our results suggest that gonad quality traits cannot be selected indirectly by selecting for body weight.Our study provides an insight into the method for improving the breeding and aquaculture of G.crenulari. 展开更多
关键词 Glyptocidaris crenularis GONAD phenotypic correlations indirect selection
下载PDF
Temporal and spatial differences and imbalance of China's urbanization development during 1950-2006 被引量:7
3
作者 方创琳 刘晓丽 《Journal of Geographical Sciences》 SCIE CSCD 2009年第6期719-732,共14页
A better understanding of the regional disparity and imbalance characteristics of China's urbanization development is the important premise for constituting correct policy and strategy and promoting the healthy an... A better understanding of the regional disparity and imbalance characteristics of China's urbanization development is the important premise for constituting correct policy and strategy and promoting the healthy and sustainable development of urbanization in the 21st century. The regional differences of China's urbanization level have close relations with natural conditions of landform and climate etc.,the urbanization level reduces with the eleva-tion of topography and decrease of precipitation. According to the statistical data set of ur-banization in 1950-2006,the temporal change course of inter-provincial disparity of Chinese urbanization level since the founding of New China in 1949 was studied,and then the inter-regional and intra-regional disparities of urbanization development were analyzed by the Theil index and its nested decomposition method,to grasp the dynamic change of spatial disparities of China's urbanization level on the whole. Using the imbalance index model,the imbalance status of urban population distribution relative to total population,grain output,total agricultural output value,gross output value of industry,tertiary industrial output value as well as gross regional product was discussed,to hold the balance characteristics of urbanization development relative to the regional development conditions from the macroscopic scales. 展开更多
关键词 URBANIZATION DIFFERENCE imbalance index China
下载PDF
Soil Disturbance from Different Mechanised Harvesting in Hill Tropical Forest, Peninsular Malaysia
4
作者 Mohd Hasmadi Ismail Norizah Kamarudin 《Journal of Environmental Science and Engineering》 2010年第1期34-41,共8页
The impacts of mechanised forest harvesting to soil physical properties are the major concern by forest managers, which have the potential to impact soil sustainability and forest productivity. Malaysia is practicing ... The impacts of mechanised forest harvesting to soil physical properties are the major concern by forest managers, which have the potential to impact soil sustainability and forest productivity. Malaysia is practicing reduce impact logging (RIL) and applying code of forest harvest practice in forest harvesting and operations for sustainable forest resources management. In 2001, a machinery called Rimbaka Timber Harvester R2020-A was introduced for timber extraction for peat swamp forest and later on the machine was introduced to the hill tropical forest as an alternative to other machines. The study aimed to evaluate soil compaction (soil cone index, soil bulk density, soil moisture content and soil pore space) by Rimbaka Timber Harvester R2020-A and crawler tractor KOMATSU D60-A. A total of five samples were randomly taken using core sampler of 50 mm height and 50 mm diameter at the beneath a lug imprint for passes 1, 4 and 8. Altogether samples were 45. The locations of sample were to the fight and left of each rut centre for both machines. Treatment effects were evaluated using analysis of variance (ANOVA). Result showed that compaction by Rimbaka machine was increased bulk density from 1.14 to 1.43 g/cc, cone index from 1.94 to 3.45 g/cm3 decreased total pore space by 43% and decreased soil moisture content by 19%. Meanwhile compaction by KOMATSU D60-A was increased bulk density from 1.2 to 1.43 g/co, cone index from 1.24 to 1.94 g/cm3 decreased soil moisture content by 11% and total pore space by 6%, respectively. The value increased rapidly as more passes increase on the track surface. The higher soil disturbance by Rimbaka machine was due to physical design and specification of the machine. This study also observed that there was significant difference in the total passes of machinery used in harvesting operation. Although Rimbaka machine is showing more effected to soil compaction, the machine is a practical alternative to avoid skid trail and reduce road density in forest area. 展开更多
关键词 Soil disturbance bulk density cone index pore space harvesting operation Rimbaka harvester system crawler tractor.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部