期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
区域化结构在岩石破裂过程中的转换作用规律
1
作者 栾尊儒 《黑龙江科学》 2024年第16期5-11,共7页
岩石在单轴压缩过程中内部会发生不同程度的损伤,导致区域化结构演变,这决定了岩石裂纹的萌生及最终破坏形态。为探究岩石内部区域化结构对岩石破裂影响的相互作用机制,基于声发射手段,通过波速成像获取岩石内部区域化结构的基础数据,... 岩石在单轴压缩过程中内部会发生不同程度的损伤,导致区域化结构演变,这决定了岩石裂纹的萌生及最终破坏形态。为探究岩石内部区域化结构对岩石破裂影响的相互作用机制,基于声发射手段,通过波速成像获取岩石内部区域化结构的基础数据,运用数值模拟手段研究岩石在加载过程中各类区域化结构转换过程中的机制及其对岩石破裂起到的决定性作用。结果表明:①岩石内部区域化结构演变过程由初始结构决定,决定了其后期的相互作用转变,在加载过程中受到应力干扰作用而发生区域化结构体之间的相互转换。②岩石区域化结构在其内部空间分布的影响下,岩石裂纹萌生及最终破坏形态由其决定,岩石内部初始结构影响最终破裂关键位置区域。此结果对于岩石破裂及现场灾害防治起到预警作用。 展开更多
关键词 区域化结构 波速成像 初始结构 破裂关键位置
下载PDF
区域化结构与破裂耦合作用下的岩石破裂演化规律 被引量:1
2
作者 刘臻 姚旭龙 +2 位作者 张艳博 刘祥鑫 梁鹏 《矿业研究与开发》 CAS 北大核心 2023年第5期120-130,共11页
单轴压缩过程中,岩石内部区域化结构的演化导致破裂,破裂同样与区域化结构互相作用。为研究二者耦合作用下岩石破裂的演化规律,通过声发射-声波成像技术获取岩石内部波速数据,将其与颗粒流程序导出的颗粒信息自动匹配成组,针对加载过程... 单轴压缩过程中,岩石内部区域化结构的演化导致破裂,破裂同样与区域化结构互相作用。为研究二者耦合作用下岩石破裂的演化规律,通过声发射-声波成像技术获取岩石内部波速数据,将其与颗粒流程序导出的颗粒信息自动匹配成组,针对加载过程中区域化结构的动态演化行为,进行模型优化,对区域化结构与破裂耦合作用下的岩石破裂演化规律展开研究。结果表明:构建出的动态演化模型,其破裂形态与室内试验具有良好的相似性;在时间上,裂纹萌生于区域化结构退化演化阶段,在空间上,裂纹萌生于退化后的Ⅲ类区域化结构内部;当区域化结构强化演化时,裂纹多在边界处扩展,在力学属性较弱区域聚集成核,当区域化结构持续劣化演化时,裂纹汇集成裂纹带,并在靠近边界位置处向演化方向扩展。 展开更多
关键词 区域化结构 岩石破裂 损伤演化 颗粒流软件 数值模拟
原文传递
河北省肉牛“北繁南育”生产模式的建立 被引量:2
3
作者 贾青 李运起 +3 位作者 孙少华 丁玉臣 李瑞力 武东鹏 《河北农业大学学报》 CAS CSCD 北大核心 1999年第4期116-120,共5页
采用对比试验及典型调查试验的方法,对河北省肉牛养殖结构的区域化进行了研究。结果表明:河北省北部丰宁、隆化和南部的临漳、大厂母牛每产一头犊牛的成本分别为522.49,493.06和868.70,1176.72元。在北部... 采用对比试验及典型调查试验的方法,对河北省肉牛养殖结构的区域化进行了研究。结果表明:河北省北部丰宁、隆化和南部的临漳、大厂母牛每产一头犊牛的成本分别为522.49,493.06和868.70,1176.72元。在北部以放牧为主的饲养条件和南部放牧加补饲的条件下,12月龄犊牛体重分别为230kg以下和280kg以上,存在显著差异。在两种气候条件下,舍饲育肥均可达到较快增重。 6,18,30月龄牛调至农区育肥至550kg,可分别取得日均收益2.77, 1.67, 1.32元,出栏日龄分别为 359d,764d和1010d,均优于在北部全程放牧条件下的0.71元和1320d。应根据区域的资源优势和牛繁殖、生长发育规律,建立以北部牧区养母牛提供犊牛、架子牛,南部农区集中舍饲育肥为主要结构的“北繁南育”肉牛生产体系。 展开更多
关键词 肉牛 北繁南育 养殖结构区域化 生产体系 河北
下载PDF
Discussion on the Problem of Salt Gland of Glycine soja 被引量:6
4
作者 周三 赵可夫 《Acta Botanica Sinica》 CSCD 2003年第5期574-580,共7页
Glycine soja Sieb. et Zucc. plants living in saline soil in three provinces of China were treated with different salinity concentrations under different laboratory culture conditions (including solution, sand and fiel... Glycine soja Sieb. et Zucc. plants living in saline soil in three provinces of China were treated with different salinity concentrations under different laboratory culture conditions (including solution, sand and field cultivation). The attachment shape and distribution on the surface of stalk and leaf of G. soja plants were observed with scanning electron microscopy (SEM), and the ultrastructure of glandular hair with transmission electron microscopy (TEM). Na+ and Cl- contents in the secretion of the leaf surface and inside the leaf of G. soja subjected to different treatments were measured. The Na+ relative contents in glandular cells, epidermal cells and mesophyllous cells of leaves under different salinities were determined by X-ray microanalysis. Results show that only glandular and epidermal hair exist on the surface attachments of leaves and stalks of G. soja plants. These glandular hair were similar in shape to some salt glands of Gramineae halophytes, and they attached to the vein on the leaf surface. The cell structure of the glandular hair showed the characteristics of common salt glands, such as big vacuoles, dense cytoplasm, a great deal of mitochondria, chloroplast, plasmodesmata and thicker cell walls, etc. The results of Na+ and Cl- contents in the leaf secretion and inside the leaf showed that the glandular hair executed the function of salt-secretion, and when treated with the salt gland inhibitor the salt-secretion process was inhibited. As a result, Na+ and Cl- were mainly accumulated inside G. soja leaves. The results of Na+ X-ray microanalysis under different salinities proved that the three cells of the glandular hair, especially the top cell, possessed strong competence for Na+ accumulation. Above all, the glandular hair were the salt gland, and no other kind of salt glands were found on G. soja plants. The secreting mechanism of the salt gland was also discussed. 展开更多
关键词 Glycine soja salt gland ULTRASTRUCTURE ion compartmentalization
下载PDF
Eco-economic Background of Hilly-Gullied Loess Region and Optimized Eco-productive Paradigm of Small Watersheds 被引量:3
5
作者 孔正红 张新时 朱桂杰 《Acta Botanica Sinica》 CSCD 2003年第10期1174-1185,共12页
A thorough analysis on its natural environment as well as social economic status of the hilly-gullied loess region is presented. A small watershed, the dominant landscape unit of the region, has been singled out for f... A thorough analysis on its natural environment as well as social economic status of the hilly-gullied loess region is presented. A small watershed, the dominant landscape unit of the region, has been singled out for further and specific study on landscape pattern and function, its social and economic distinctions. The authors proposed several principles based on its eco-economic background study, which includes water balance and efficient use principle, co-development of grass and agro-forestry principle, location optimization principle. Integrated with detailed analysis of a small watershed, an eco-productive paradigm for the loess land's development based on a small watershed scale was worked out. It consists of circle pattern with villages at core for high efficient agriculture production, hierarchical pattern along the slope for eco-economic development, point-axis pattern for commodity production and circulation in small watersheds and core-margin pattern for exchanges among watersheds. 展开更多
关键词 hilly-gullied loess region small watershed landscape pattern and function location optimization
下载PDF
De novo assembly of a Chinese soybean genome 被引量:15
6
作者 Yanting Shen Jing Liu +7 位作者 Haiying Geng Jixiang Zhang Yucheng Liu Haikuan Zhang Shilai Xing Jianchang Du Shisong Ma Zhixi Tian 《Science China(Life Sciences)》 SCIE CAS CSCD 2018年第8期871-884,共14页
Soybean was domesticated in China and has become one of the most important oilseed crops. Due to bottlenecks in their introduction and dissemination, soybeans from different geographic areas exhibit extensive genetic ... Soybean was domesticated in China and has become one of the most important oilseed crops. Due to bottlenecks in their introduction and dissemination, soybeans from different geographic areas exhibit extensive genetic diversity. Asia is the largest soybean market; therefore, a high-quality soybean reference genome from this area is critical for soybean research and breeding.Here, we report the de novo assembly and sequence analysis of a Chinese soybean genome for "Zhonghuang 13" by a combination of SMRT, Hi-C and optical mapping data. The assembled genome size is 1.025 Gb with a contig N50 of 3.46 Mb and a scaffold N50 of 51.87 Mb. Comparisons between this genome and the previously reported reference genome(cv. Williams82) uncovered more than 250,000 structure variations. A total of 52,051 protein coding genes and 36,429 transposable elements were annotated for this genome, and a gene co-expression network including 39,967 genes was also established. This high quality Chinese soybean genome and its sequence analysis will provide valuable information for soybean improvement in the future. 展开更多
关键词 de novo soybean genome Zhonghuang 13 Gmax_ZH13 structure variation gene co-expression network
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部