期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
冲击荷载作用下各向异性煤体中大孔结构变化规律研究
1
作者 梁为民 李晓鹏 李敏敏 《煤炭科学技术》 CAS CSCD 北大核心 2022年第11期100-109,共10页
为了研究冲击荷载对煤岩体孔隙结构中中大孔结构的影响,能够为煤层增透中爆破致裂技术参数的设置提供相关理论依据,对结构异性(垂直于层理方向、平行于层理方向)煤岩体采用分离式霍普金森压杆(Split Hopkinson Pressure Bar, SHPB)冲击... 为了研究冲击荷载对煤岩体孔隙结构中中大孔结构的影响,能够为煤层增透中爆破致裂技术参数的设置提供相关理论依据,对结构异性(垂直于层理方向、平行于层理方向)煤岩体采用分离式霍普金森压杆(Split Hopkinson Pressure Bar, SHPB)冲击试验,进行不同冲击气压(0.1、0.15、0.2、0.3、0.5 MPa)下的动态力学性能测试,然后利用压汞试验对不同冲击荷载下结构异性煤岩体进行孔径结构分析,进而探讨冲击荷载对结构异性煤岩体中中大孔结构的影响规律。结果表明:煤样的动态抗压强度随着冲击荷载的增加呈线性增加,当冲击荷载相同时,垂直层理方向煤样的动态抗压强度均大于平行层理方向。冲击荷载和层理方向对煤样的进退汞曲线特征、孔隙度、退汞效率和孔径分布均有影响,当冲击气压为0.5 MPa时,对应垂直层理和平行层理方向动态抗压强度分别为29.624、24.339 MPa,较未受冲击荷载相比,垂直层理方向和平行层理方向煤样进汞量分别增加188%、205%,孔隙度分别增加155%、198%,退汞效率分别减少32%、69%,孔径分布中孔容最大值分别增加472%、492%。不同层理方向冲击荷载对煤样的孔隙结构的改善效果不同,当冲击荷载相同时,平行层理方向煤样的进汞量、孔隙度、退汞效率、孔容最大值,分别为垂直层理方向煤样的1.05、1.35、0.46和1.40倍。总体上,冲击荷载越大,煤样总孔容增量越大,且平行层理方向煤样总孔容增量大于垂直层理方向。 展开更多
关键词 煤岩 冲击荷载 霍普金森压杆 结构异性 压汞试验 中大孔
下载PDF
中大孔催化裂化催化剂研究进展 被引量:6
2
作者 熊晓云 赵红娟 +1 位作者 胡清勋 高雄厚 《工业催化》 CAS 2019年第1期6-10,共5页
发展中大孔型催化剂是催化裂化催化剂的主要发展方向之一,催化裂化催化剂中引入中大孔的主要方法有高岭土酸碱改性法、引入大孔硅铝基材料法、引入介孔分子筛法、原位晶化法和模板法。酸碱改性高岭土的孔结构受原料影响较大,孔径一般小... 发展中大孔型催化剂是催化裂化催化剂的主要发展方向之一,催化裂化催化剂中引入中大孔的主要方法有高岭土酸碱改性法、引入大孔硅铝基材料法、引入介孔分子筛法、原位晶化法和模板法。酸碱改性高岭土的孔结构受原料影响较大,孔径一般小于10 nm;制备大孔硅铝基材料替代拟薄水铝石可有效改善催化剂的孔结构,但应关注对催化剂强度的影响;分子筛中引入介孔又包括水热处理法,酸、碱处理法和引入不稳定位点法,工业应用范围广,但处理过程中易造成Y型分子筛结晶度下降,并缺乏连续、贯通型孔道;原位晶化法是工业上较成功的中大孔催化剂制备方法,但能耗相对高,流程长;模板法可通过改变模板类型、含量对催化剂孔结构调变,但应关注环保及催化剂强度问题。 展开更多
关键词 催化剂工程 催化裂化 重油转化 中大孔催化剂
下载PDF
Primary Meningeal Melanocytoma Located in Foramen Magnum:a Case Report and Review of the Literatures
3
作者 Ming-chao Fan Jing-feng Wang +3 位作者 Wei-wei Fu Ke Liu Lian-di Li Peng Sun 《Chinese Medical Sciences Journal》 CAS CSCD 2012年第2期115-120,共6页
LIMAS and Tio1 proposed the term meningeal melanocytoma first time in 1972 to describe a primary melanotic tumor of the leptomeninges with prolonged clinical course and benign histology.Meningeal melanocytoma of the c... LIMAS and Tio1 proposed the term meningeal melanocytoma first time in 1972 to describe a primary melanotic tumor of the leptomeninges with prolonged clinical course and benign histology.Meningeal melanocytoma of the central nervous system is rare and benign primary meningeal melanocytoma (PMM) is more exceptional,and also less usual than the malignant types.2 This rare tumor falls under the subclassification of primary melanocytic lesions in the World Health Organization's classification of central nervous system tumors.3 PMM located in the foramen magnum region is an unusual cause of bulbus medullae and fourth ventricle compression.Here we report a 48-year-old man with a PMM which is located in the foramen magnum inducing supratentorial obstructive hydrocephalus. 展开更多
关键词 foramen magnum meningeal melanocytoma HISTOPATHOLOGY NEUROIMAGING obstructive hydrocephalus
下载PDF
Research on the control technology of medium-length hole blasting fragmentation in underground mine
4
作者 Zhao Yanwei He Dongmei Liu Junxuan 《Engineering Sciences》 EI 2014年第6期52-57,共6页
The scalloped medium-length hole blasting mining method used in Dahongshan Copper Mine accounted for more than 61%of the total amount of mining,but the large boulder yield restricted the intensity of ore supply for mi... The scalloped medium-length hole blasting mining method used in Dahongshan Copper Mine accounted for more than 61%of the total amount of mining,but the large boulder yield restricted the intensity of ore supply for mines,and the average boulder yield was as high as 22.7%.In order to develop the mine production efficiency,the circular medium-length hole blasting technology was proposed and field tests were carried out.The test results showed that circular medium-length hole blasting mining can reduce the average boulder yield to 10.3%.Compared with the traditional scalloped medium-length hole blasting mining,the average boulder yield was decreased by 12.4%.The daily yield of ore for the panel on duty was increased by 152.29 t,and the growth rate was 51.1%.The new technology can reduce the time for the handling of boulder and the consumption of explosives and detonators for recrushing,and increase the efficiency of mining while reduce the mining cost,which has received good blasting effects. 展开更多
关键词 scalloped medium-length hole blasting circular medium-length hole blasting lump ore blastingeffect
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部