With the support of RS and GIS technology,the ecological environment of Linze was evaluated and the changes of ecological environment were analyzed from the spatial scope of ecosystem with the remote sensing images in...With the support of RS and GIS technology,the ecological environment of Linze was evaluated and the changes of ecological environment were analyzed from the spatial scope of ecosystem with the remote sensing images in 2000 and 2017 as the information source.The results showed that the areas with excellent,relatively good and relatively poor ecological environment in Linze showed a decreasing trend from 2000 to 2017,which decreased by 262.50,7,156.25 and 12,256.30 hm^2,respectively.From the landscape patch pattern,the patch density in areas with relatively good ecological environment increased the fastest from 2000 to 2017,which was 13.05 pieces/hm^2.The largest plaque index in areas with relatively good ecological environment decreased by 1.314%,and the dominance of large plaque in the region decreased.The assessment results of ecological environment based on remote sensing demonstrated that the ecological environment in Linze was generally healthy from 2000 to 2017,and the deterioration was improved.Among them,the area transformed from relatively poor ecological environment to other types was the largest,which was 17,512.92 hm^2,and the proportion of the area transformed into general ecological environment was the highest,accounting for 80.7%of the transformed area of the region.展开更多
Standard asphalt mixtures for road infrastructures consist of natural aggregate and bitumen. A number of research efforts have successfully investigated the possibility of replacing the conventional aggregate skeleton...Standard asphalt mixtures for road infrastructures consist of natural aggregate and bitumen. A number of research efforts have successfully investigated the possibility of replacing the conventional aggregate skeleton with industrial by-products such as slag originating from steel production process. However, little is known on the effect of steel slag on the mixtures performance properties such as resistance to low-temperature cracking and to permanent deformation, stiffness and fatigue. This paper presents a comprehensive investigation on the fundamental performance properties of different types of asphalt mixtures prepared with 100% LD slag aggregate and a conventional asphalt mixture containing natural Gabbro aggregate. Sophisticated testing methods were used to evaluate the key performance parameters for the set of asphalt mixtures investigated. In this study, low temperature cracking was addressed through thermal stress restrained specimen tests. Penetration tests and cyclic compression tests were used to evaluate the response of asphalt binder and asphalt mixture to permanent deformation due repeated loading, respectively. The cyclic indirect tensile test was selected for investigating both stiffness properties and fatigue resistance. For this purpose the complex stiffness modulus was measured to quantify material stiffness under different temperature and loading conditions providing information on the visco-elasto-plastic material behavior. Fatigue tests were used to determine the progressive and localized material damage caused by cyclic loading. The experimental results indicate that asphalt mixtures prepared with LD slag are suitable for asphalt pavement construction and that in most cases they perform better than conventional asphalt mixtures prepared with Gabbro aggregate.展开更多
旅行中发生的人事和情感,那些独家记忆,其实是"不足道"的,别人不懂得,自己说来也难为情。如果硬要说起,我能想到唯一的理由,不过是作个纪念,纪念那些寡廉鲜耻动用文艺界让人嗤笑不已的两个严重字眼——羁绊。借用很久以前信...旅行中发生的人事和情感,那些独家记忆,其实是"不足道"的,别人不懂得,自己说来也难为情。如果硬要说起,我能想到唯一的理由,不过是作个纪念,纪念那些寡廉鲜耻动用文艺界让人嗤笑不已的两个严重字眼——羁绊。借用很久以前信乐团在《one night in北京》唱的,我们行到百花深处,留下了许多情。展开更多
文摘With the support of RS and GIS technology,the ecological environment of Linze was evaluated and the changes of ecological environment were analyzed from the spatial scope of ecosystem with the remote sensing images in 2000 and 2017 as the information source.The results showed that the areas with excellent,relatively good and relatively poor ecological environment in Linze showed a decreasing trend from 2000 to 2017,which decreased by 262.50,7,156.25 and 12,256.30 hm^2,respectively.From the landscape patch pattern,the patch density in areas with relatively good ecological environment increased the fastest from 2000 to 2017,which was 13.05 pieces/hm^2.The largest plaque index in areas with relatively good ecological environment decreased by 1.314%,and the dominance of large plaque in the region decreased.The assessment results of ecological environment based on remote sensing demonstrated that the ecological environment in Linze was generally healthy from 2000 to 2017,and the deterioration was improved.Among them,the area transformed from relatively poor ecological environment to other types was the largest,which was 17,512.92 hm^2,and the proportion of the area transformed into general ecological environment was the highest,accounting for 80.7%of the transformed area of the region.
文摘Standard asphalt mixtures for road infrastructures consist of natural aggregate and bitumen. A number of research efforts have successfully investigated the possibility of replacing the conventional aggregate skeleton with industrial by-products such as slag originating from steel production process. However, little is known on the effect of steel slag on the mixtures performance properties such as resistance to low-temperature cracking and to permanent deformation, stiffness and fatigue. This paper presents a comprehensive investigation on the fundamental performance properties of different types of asphalt mixtures prepared with 100% LD slag aggregate and a conventional asphalt mixture containing natural Gabbro aggregate. Sophisticated testing methods were used to evaluate the key performance parameters for the set of asphalt mixtures investigated. In this study, low temperature cracking was addressed through thermal stress restrained specimen tests. Penetration tests and cyclic compression tests were used to evaluate the response of asphalt binder and asphalt mixture to permanent deformation due repeated loading, respectively. The cyclic indirect tensile test was selected for investigating both stiffness properties and fatigue resistance. For this purpose the complex stiffness modulus was measured to quantify material stiffness under different temperature and loading conditions providing information on the visco-elasto-plastic material behavior. Fatigue tests were used to determine the progressive and localized material damage caused by cyclic loading. The experimental results indicate that asphalt mixtures prepared with LD slag are suitable for asphalt pavement construction and that in most cases they perform better than conventional asphalt mixtures prepared with Gabbro aggregate.
文摘在大田环境下, 通过建造2 m×2 m×2 m的封底观测池, 利用水量平衡法, 研究了甘肃省河西走廊中部黑河中游绿洲临泽小枣、春小麦、紫花苜蓿单作及临泽小枣/春小麦、临泽小枣/紫花苜蓿间作复合系统的需水规律。结果表明, 内部绿洲和边缘绿洲的临泽小枣从根系开始活动到落叶的需水量分别为497.2 mm和859.2 mm, 春小麦从播种到收获需水量分别为447.9 mm 和809.9 mm, 紫花苜蓿从返青到霜降需水量分别为583.7 mm 和945.7 mm, 临泽小枣/春小麦复合系统需水量分别为647.7 mm 和1 009.7 mm, 临泽小枣/紫花苜蓿复合系统需水量分别为980.3 mm 和1 342.3 mm。边缘绿洲临泽小枣/春小麦复合系统增加的需水量为枣树需水量的17.5%, 小麦需水量的24.7%; 临泽小枣/紫花苜蓿复合系统增加的需水量为枣树需水量的56.2%, 紫花苜蓿需水量的41.9%。内部绿洲临泽小枣春季（4月25日～5月31日）需水量为84.6 mm, 夏季（6月1日～8月31日）为351.3 mm, 秋季（9月1日～10月5日）为61.3 mm; 7月份需水强度最大, 为4.8 mm·d^-1, 6月份次之, 为4.3 mm·d^-1, 生长期平均需水强度为3.1 mm·d^-1。临泽小枣灌溉应保证4个关键水, 即花前水、果实膨大水、丰果水和越冬水, 灌水定额为1 200 m^3·hm^-2。
