The dislocation equations of a simple cubic lattice have been obtained by using Green＇s function method based on the discrete lattice theory with the coefficients of the secondorder differential terms and the integra...The dislocation equations of a simple cubic lattice have been obtained by using Green＇s function method based on the discrete lattice theory with the coefficients of the secondorder differential terms and the integral terms have been given explicitly in advance. The simple cubic lattice we have discussed is a solvable model, which is obtained according to the lattice statics and the symmetry principle and can verify and validate the dislocation lattice theory. It can present unified dislocation equations which are suitable for most of metals with arbitral lattice structures. Through comparing the results of the present solvable model with the dislocation lattice theory, it can be seen that, the coefficients of integral terms of the edge and screw components we obtain are in accordance with the results of the dislocation lattice theory, however, the coefficient of the second-order differential term of the screw component is not in agreement with the result of the dislocation lattice theory. This is mainly caused by the reduced dynamical matrix of the surface term, which is the essence to obtain the dislocation equation. According to the simple cubic solvable model, not only the straight dislocations but also the curved dislocations, such as the kink, can be investigated further.展开更多
目的:探讨痉挛型脑瘫患儿粗大运动功能分级(gross motor function classification system,GMFCS)与髋关节、腰椎发育的关系。方法:回顾性分析2018年1月至2021年7月收治的125例痉挛型脑瘫患儿,男85例,女40例,年龄4~12(8.4±2.9)岁。...目的:探讨痉挛型脑瘫患儿粗大运动功能分级(gross motor function classification system,GMFCS)与髋关节、腰椎发育的关系。方法:回顾性分析2018年1月至2021年7月收治的125例痉挛型脑瘫患儿,男85例,女40例,年龄4~12(8.4±2.9)岁。依据GMFCS分为Ⅰ、Ⅱ、Ⅲ、Ⅳ级组。其中Ⅰ级组27例,Ⅱ级组40例,Ⅲ级组35例,Ⅳ级组23例。通过骨盆正位X线片,测量股骨头偏移百分比(migration percentage,MP)、中心边缘角(central edge angle,CE),颈干角(neck-shaft angle,NSA)、髋臼指数(acetabular index,AI),并选取其严重侧髋关节参数值分析,评价不同GMFCS分级与髋关节发育的关系。通过腰椎侧位X线片,测量腰椎矢状位Cobb角、腰骶角、腰椎前凸指数、弓顶距,评价不同GMFCS分级与腰椎发育的关系。结果:(1)119例痉挛型脑瘫患儿的骨盆正位X线片符合测量标准。Ⅰ-Ⅳ级4组MP分别为(22.72±3.88)、(26.53±4.36)、(33.84±4.99)、(49.54±7.87)%,两两比较差异均有统计学意义(P<0.05);4组CE分别为(30.10±6.99)°、(22.92±4.19)°、(17.91±5.50)°、(-0.70±17.33)°,两两比较差异均有统计学意义(P<0.05);4组AI分别为(16.41±2.77)°、(20.46±4.63)°、(23.76±5.10)°、(29.15±7.35)°,两两比较差异均有统计学意义(P<0.05);且GMFCS分级越高,MP和AI越大,CE越小。Ⅰ-Ⅳ级4组NSA分别为(142.74±10.03)°、(148.66±9.09)°、(151.66±10.52)°、(153.70±8.05)°,GMFCSⅠ级组与其余3组两两比较差异均有统计学意义(P<0.05),GMFCSⅠ级组NSA明显低于其他3组,其余组间两两比较差异均无统计学意义(P>0.05)。(2)88例痉挛型患儿的腰椎侧位X线片符合测量标准。Ⅰ-Ⅳ级4组腰椎矢状位Cobb角分别为(32.62±11.10)°、(29.86±9.90)°、(31.70±11.84)°、(39.69±6.80)°,GMFCSⅣ级腰椎矢状位Cobb角明显高于其余3组,两两比较差异均有统计学意义(P<0.05)。其余各组间两两比较差异均无统计学意义(P>0.05);4组腰骶角分别为(31.02±9.91)°、(26.57±9.41)°、展开更多
A statistical distribution function of the dislocation link length,in unit volume of the crystalline materials has been derived theoretically after semi-infinite normalization by as- suming the distribution of actual ...A statistical distribution function of the dislocation link length,in unit volume of the crystalline materials has been derived theoretically after semi-infinite normalization by as- suming the distribution of actual links in all positions of crystalline materials with equal prob- ability,i.e. (l)dl=2ρl_γ^(-4)l^2exp(l^2/l_γ~2)dl where ρ is dislocation density,This assumption seems to be reasonable for polycrystalline fec metallic materials,and confirmation has been found in pure Ni and stainless steel 1Cr18Ni9Ti TEM experiments alresults.展开更多
基金supported by the National Natural Science Foundation of China (No. 11074313)
文摘The dislocation equations of a simple cubic lattice have been obtained by using Green＇s function method based on the discrete lattice theory with the coefficients of the secondorder differential terms and the integral terms have been given explicitly in advance. The simple cubic lattice we have discussed is a solvable model, which is obtained according to the lattice statics and the symmetry principle and can verify and validate the dislocation lattice theory. It can present unified dislocation equations which are suitable for most of metals with arbitral lattice structures. Through comparing the results of the present solvable model with the dislocation lattice theory, it can be seen that, the coefficients of integral terms of the edge and screw components we obtain are in accordance with the results of the dislocation lattice theory, however, the coefficient of the second-order differential term of the screw component is not in agreement with the result of the dislocation lattice theory. This is mainly caused by the reduced dynamical matrix of the surface term, which is the essence to obtain the dislocation equation. According to the simple cubic solvable model, not only the straight dislocations but also the curved dislocations, such as the kink, can be investigated further.
文摘目的:探讨痉挛型脑瘫患儿粗大运动功能分级(gross motor function classification system,GMFCS)与髋关节、腰椎发育的关系。方法:回顾性分析2018年1月至2021年7月收治的125例痉挛型脑瘫患儿,男85例,女40例,年龄4~12(8.4±2.9)岁。依据GMFCS分为Ⅰ、Ⅱ、Ⅲ、Ⅳ级组。其中Ⅰ级组27例,Ⅱ级组40例,Ⅲ级组35例,Ⅳ级组23例。通过骨盆正位X线片,测量股骨头偏移百分比(migration percentage,MP)、中心边缘角(central edge angle,CE),颈干角(neck-shaft angle,NSA)、髋臼指数(acetabular index,AI),并选取其严重侧髋关节参数值分析,评价不同GMFCS分级与髋关节发育的关系。通过腰椎侧位X线片,测量腰椎矢状位Cobb角、腰骶角、腰椎前凸指数、弓顶距,评价不同GMFCS分级与腰椎发育的关系。结果:(1)119例痉挛型脑瘫患儿的骨盆正位X线片符合测量标准。Ⅰ-Ⅳ级4组MP分别为(22.72±3.88)、(26.53±4.36)、(33.84±4.99)、(49.54±7.87)%,两两比较差异均有统计学意义(P<0.05);4组CE分别为(30.10±6.99)°、(22.92±4.19)°、(17.91±5.50)°、(-0.70±17.33)°,两两比较差异均有统计学意义(P<0.05);4组AI分别为(16.41±2.77)°、(20.46±4.63)°、(23.76±5.10)°、(29.15±7.35)°,两两比较差异均有统计学意义(P<0.05);且GMFCS分级越高,MP和AI越大,CE越小。Ⅰ-Ⅳ级4组NSA分别为(142.74±10.03)°、(148.66±9.09)°、(151.66±10.52)°、(153.70±8.05)°,GMFCSⅠ级组与其余3组两两比较差异均有统计学意义(P<0.05),GMFCSⅠ级组NSA明显低于其他3组,其余组间两两比较差异均无统计学意义(P>0.05)。(2)88例痉挛型患儿的腰椎侧位X线片符合测量标准。Ⅰ-Ⅳ级4组腰椎矢状位Cobb角分别为(32.62±11.10)°、(29.86±9.90)°、(31.70±11.84)°、(39.69±6.80)°,GMFCSⅣ级腰椎矢状位Cobb角明显高于其余3组,两两比较差异均有统计学意义(P<0.05)。其余各组间两两比较差异均无统计学意义(P>0.05);4组腰骶角分别为(31.02±9.91)°、(26.57±9.41)°、
文摘A statistical distribution function of the dislocation link length,in unit volume of the crystalline materials has been derived theoretically after semi-infinite normalization by as- suming the distribution of actual links in all positions of crystalline materials with equal prob- ability,i.e. (l)dl=2ρl_γ^(-4)l^2exp(l^2/l_γ~2)dl where ρ is dislocation density,This assumption seems to be reasonable for polycrystalline fec metallic materials,and confirmation has been found in pure Ni and stainless steel 1Cr18Ni9Ti TEM experiments alresults.
