With the methods of regression analysis and trend surface analysis, taking the bottom and top lines of dark conifer forest, bottom line of permafrost and the snowline of the latest glaciation in China as examples, thi...With the methods of regression analysis and trend surface analysis, taking the bottom and top lines of dark conifer forest, bottom line of permafrost and the snowline of the latest glaciation in China as examples, this paper discusses the zonality regulaties of the distribution of physico-geographical zones in China. (1) Latitude zonality obeys the mathematical model of normal frequency distribution, being approximate to descending straightly within the latitude of China. (2) Longitude zonality shows that the elevation of physico-geographical zone rises straightly with the distance to east coast. (3) The combination of latitude and longitude zonalities appears a plane inclining from SSW to NNE. The decline of physico-geographical zone resembles a semiellipse- sphere inclining from the Qinghai-Xizang (Tibet) Plateau to northeast China, reflecting the effect of relief. (5) Physico-geographical zonation depends on the combination of hydrothermal conditions. Thus the factors influencing the distribution展开更多
The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yon...The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yongledian Quarry in Beijing.Through determination and analysis of soil physical and chemical properties,it shows that there are significant differences in the composite effects of soil physical and chemical properties between restored area,and undisturbed area,damaged area,and engineering restoration effectively improves the composite effects of soil physical and chemical properties in the restored area.The single factor hypothesis test shows that soil pH value,organic matter,alkali-hydrolyzable nitrogen,and total nitrogen traits are the key targets to be restored in this mining area.展开更多
The growth plate is a thin layer of cartilage sandwiched between epiphyseal and metaphyseal bone and is the location of active bone growth during childhood. It is subjected to large compressive and shear forces while ...The growth plate is a thin layer of cartilage sandwiched between epiphyseal and metaphyseal bone and is the location of active bone growth during childhood. It is subjected to large compressive and shear forces while protecting its resident chondrocytes from damage. We believe that computational modeling can help us better understand how the macro-scale loads are transmitted to micro-scale stresses and strains within the growth plate cartilage. As a first step in this process we analyzed the mechanical response of compression experiments performed on bovine bone/growth plate/bone samples. We endeavored to estimate the modulus of elasticity of the growth plate itself by simulating the compression experiments of these specimens using the finite element method. It is shown that when the growth plate in the compression specimens was modeled as a flat layer, the state of stress in the cartilage was triaxial and non-uniform with the hydrostatic stress being much greater than the octahedral shear stress over most of the central region of the growth plate test samples. The computational models accounted for variations in the average cartilage thickness, the non-uniaxial, non-uniform and triaxial state of stress in the thin cartilage layer, and for the estimated extrinsic compliance resulting from compression of the variable heights of bone on either side of the growth plate cartilage. However, due to lack of information on the internal structure of each sample, the models did not account for the variations in the non-flat topography of the growth plates. The models also did not include the calcified cartilage layer. Further model development is recommendedin order to determine the degree to which accounting for the complex growth plate topography influences the predicted cartilage modulus of elasticity.展开更多
This study investigated the effects of carbon nanotube （CNT） concentration on the micro-morphologies and laser absorption proper- ties of CNT/AlSi10Mg composite powders produced by high-energy ball milling. A scanni...This study investigated the effects of carbon nanotube （CNT） concentration on the micro-morphologies and laser absorption proper- ties of CNT/AlSi10Mg composite powders produced by high-energy ball milling. A scanning electron microscope, X-ray diffractometer, laser particle size analyzer, high-temperature synchronous thermal analyzer, and UV/VIS/NIR spectrophotometer were used for the analysis of micro- graphs, phases, granulometric parameters, thermal properties, and laser absorption properties of the composite powders, respectively. The results showed that the powders gradually changed from flake- to granule-like morphology and the average particle size sharply decreased with in- creases in milling rotational speed and milling time. Moreover, a uniform dispersion of CNTs in AlSi10Mg powders was achieved only for a CNT content of 1.5wt%. Laser absorption values of the composite powders were also observed to gradually increase with the increase of CNT concentration, and different spectra displayed characteristic absorption peaks at a wavelength of approximately 826 nm.展开更多
In Physics B 1, Aristotle establishes a detailed definition ofphysis. For that purpose, Aristotle distinguishes physis from rechne and his domain. He did this to offer a satisfactory account of the physical being. In ...In Physics B 1, Aristotle establishes a detailed definition ofphysis. For that purpose, Aristotle distinguishes physis from rechne and his domain. He did this to offer a satisfactory account of the physical being. In this process, phf;sis is defined as an immanent principle of movement and as matter and as form. As matter physis could be understood as ＂the primary underlying matter in each case, of things which have in themselves a source of their movements and changes＂. To consider physis as form Aristotle appeals to four arguments where priority of form over matter appears to be evident and where the identifying of eidos/morphe with to telos/to hou heneka will be crucial, especially for later developments. The reconstruction of Aristotle＇s reasoning on his definition ofphysis in Physics B 1 emphasizing the problems that such effort of definition implies is the purpose of this paper.展开更多
文摘With the methods of regression analysis and trend surface analysis, taking the bottom and top lines of dark conifer forest, bottom line of permafrost and the snowline of the latest glaciation in China as examples, this paper discusses the zonality regulaties of the distribution of physico-geographical zones in China. (1) Latitude zonality obeys the mathematical model of normal frequency distribution, being approximate to descending straightly within the latitude of China. (2) Longitude zonality shows that the elevation of physico-geographical zone rises straightly with the distance to east coast. (3) The combination of latitude and longitude zonalities appears a plane inclining from SSW to NNE. The decline of physico-geographical zone resembles a semiellipse- sphere inclining from the Qinghai-Xizang (Tibet) Plateau to northeast China, reflecting the effect of relief. (5) Physico-geographical zonation depends on the combination of hydrothermal conditions. Thus the factors influencing the distribution
文摘The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yongledian Quarry in Beijing.Through determination and analysis of soil physical and chemical properties,it shows that there are significant differences in the composite effects of soil physical and chemical properties between restored area,and undisturbed area,damaged area,and engineering restoration effectively improves the composite effects of soil physical and chemical properties in the restored area.The single factor hypothesis test shows that soil pH value,organic matter,alkali-hydrolyzable nitrogen,and total nitrogen traits are the key targets to be restored in this mining area.
文摘The growth plate is a thin layer of cartilage sandwiched between epiphyseal and metaphyseal bone and is the location of active bone growth during childhood. It is subjected to large compressive and shear forces while protecting its resident chondrocytes from damage. We believe that computational modeling can help us better understand how the macro-scale loads are transmitted to micro-scale stresses and strains within the growth plate cartilage. As a first step in this process we analyzed the mechanical response of compression experiments performed on bovine bone/growth plate/bone samples. We endeavored to estimate the modulus of elasticity of the growth plate itself by simulating the compression experiments of these specimens using the finite element method. It is shown that when the growth plate in the compression specimens was modeled as a flat layer, the state of stress in the cartilage was triaxial and non-uniform with the hydrostatic stress being much greater than the octahedral shear stress over most of the central region of the growth plate test samples. The computational models accounted for variations in the average cartilage thickness, the non-uniaxial, non-uniform and triaxial state of stress in the thin cartilage layer, and for the estimated extrinsic compliance resulting from compression of the variable heights of bone on either side of the growth plate cartilage. However, due to lack of information on the internal structure of each sample, the models did not account for the variations in the non-flat topography of the growth plates. The models also did not include the calcified cartilage layer. Further model development is recommendedin order to determine the degree to which accounting for the complex growth plate topography influences the predicted cartilage modulus of elasticity.
基金financially supported by the National Natural Science Foundation of China (No. 51405467)the Research Fund for Scientific and Technological Projects of Chongqing (Nos. 2012ggB 40003 and cstc2013yykfC 00006)
文摘This study investigated the effects of carbon nanotube （CNT） concentration on the micro-morphologies and laser absorption proper- ties of CNT/AlSi10Mg composite powders produced by high-energy ball milling. A scanning electron microscope, X-ray diffractometer, laser particle size analyzer, high-temperature synchronous thermal analyzer, and UV/VIS/NIR spectrophotometer were used for the analysis of micro- graphs, phases, granulometric parameters, thermal properties, and laser absorption properties of the composite powders, respectively. The results showed that the powders gradually changed from flake- to granule-like morphology and the average particle size sharply decreased with in- creases in milling rotational speed and milling time. Moreover, a uniform dispersion of CNTs in AlSi10Mg powders was achieved only for a CNT content of 1.5wt%. Laser absorption values of the composite powders were also observed to gradually increase with the increase of CNT concentration, and different spectra displayed characteristic absorption peaks at a wavelength of approximately 826 nm.
文摘In Physics B 1, Aristotle establishes a detailed definition ofphysis. For that purpose, Aristotle distinguishes physis from rechne and his domain. He did this to offer a satisfactory account of the physical being. In this process, phf;sis is defined as an immanent principle of movement and as matter and as form. As matter physis could be understood as ＂the primary underlying matter in each case, of things which have in themselves a source of their movements and changes＂. To consider physis as form Aristotle appeals to four arguments where priority of form over matter appears to be evident and where the identifying of eidos/morphe with to telos/to hou heneka will be crucial, especially for later developments. The reconstruction of Aristotle＇s reasoning on his definition ofphysis in Physics B 1 emphasizing the problems that such effort of definition implies is the purpose of this paper.
