In order to conform to dimensional tolerances, an efficient numerical method, displacement iterative compensation method, based on finite element methodology （FEM） was presented for the wax pattern die profile desig...In order to conform to dimensional tolerances, an efficient numerical method, displacement iterative compensation method, based on finite element methodology （FEM） was presented for the wax pattern die profile design of turbine blades. Casting shrinkages at different positions of the blade which was considered nonlinear thermo-mechanical casting deformations were calculated. Based on the displacement iterative compensation method proposed, the optimized wax pattern die profile can be established. For a A356 alloy blade, substantial reduction in dimensional and shape tolerances was achieved with the developed die shape optimization system. Numerical simulation result obtained by the proposed method shows a good agreement with the result measured experimentally. After four times iterations, compared with the CAD model of turbine blade, the total form error decreases to 0.001 978 mm from the orevious 0.515 815 mm.展开更多
As an important index affecting the aerodynamic performance and the structural strength of hollow turbine blades, the wall-thickness precision of the blade is mainly inherited from the positional relationship between ...As an important index affecting the aerodynamic performance and the structural strength of hollow turbine blades, the wall-thickness precision of the blade is mainly inherited from the positional relationship between the corresponding wax pattern and the internal ceramic core.However, due to locating errors, the actual position of ceramic core is always deviated from the ideal position, which makes it difficult to guarantee the wall-thickness precision of the wax pattern.To solve this problem, a wall-thickness compensation strategy is proposed in this paper. Firstly,based on the industrial computed tomography(ICT) technique and curve matching algorithms, a model reconstruction method is developed, with which the 3D model of a trial wax pattern can be easily constructed. After that, focusing on eliminating the wall-thickness errors of the trial wax pattern, an optimization method for the pose of the ceramic core in the wax pattern is proposed. Then, by mapping the optimal pose of the ceramic core to length adjustments of the locating rods, the wall-thickness errors of the wax pattern can be greatly reduced. A case study is also given to illustrate the effectiveness of the proposed compensation strategy.展开更多
The aim of this study is to evaluate the maximum and minimum distances between the model and the cast crown of three techniques using Scanning Electron Microscopy (SEM). Three technique groups were used for this study...The aim of this study is to evaluate the maximum and minimum distances between the model and the cast crown of three techniques using Scanning Electron Microscopy (SEM). Three technique groups were used for this study: group A (control), traditional manual wax patterns;group B, dipping wax patterns;group C, resin patterns made with CAD/CAM. For each group, 10 samples were made using the same model, and then metal cast. Marginal accuracies of the samples were evaluated by performing gap measurements using SEM with a magnification of 1200× (minimum distance). The data were statistically analyzed using the one-way analysis of variance (ANOVA) at the 0.05 significance level. The average (standard deviation) of the minimum distance [μm] was 22.5 (12.1), 9.9 (4.3), and 14.7 (6.6), in groups A, B, and C, respectively. The average standard deviation of gap area [μm2] was 21667.2 (3476.4), 9906.4 (1512.1), and 16048.8 (8123). In the minimum distance comparison, groups A and B (p = 0.006) showed statistically significant results. In the gap area comparison, there was no statistical significance among groups A, B, and C (p = 0.174). The marginal adaptations of all three techniques were within a reported clinically acceptable range of margin.展开更多
SOC1(SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1)是植物中的一个开花时间调节因子,属于MADS-box转录因子家族,在植物从营养生长向生殖生长的转变中发挥关键作用。SOC1参与多种生物过程,包括花器官发育、开花时间控制以及对环境刺激...SOC1(SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1)是植物中的一个开花时间调节因子,属于MADS-box转录因子家族,在植物从营养生长向生殖生长的转变中发挥关键作用。SOC1参与多种生物过程,包括花器官发育、开花时间控制以及对环境刺激和激素信号的响应。本研究通过遮荫和喷施乐斯本的方式对莲雾进行催花处理,统计处理后的叶芽和花芽数量以及成花枝率,同时,利用课题组现有的莲雾转录组进行分析,筛选出调控莲雾开花的候选基因SsSOC1,并通过实时荧光定量PCR技术研究遮荫处理和喷施乐斯本药剂处理下莲雾不同时期和组织中SsSOC1表达量的差异。结果显示:经过遮荫处理的莲雾树体芽点、叶片、叶尖以及叶柄中的SsSOC1基因表达量显著增加,其中叶尖的相对表达量最高。本研究成功克隆了莲雾黑糖芭比品种的SsSOC1基因,并利用生物信息学方法对其进行启动子分析、蛋白理化性质分析、保守功能域的预测和序列比对。结果表明:SsSOC1基因的开放阅读框长度为654 bp,共编码217个氨基酸,其编码蛋白的理论等电点为9.37,分子式为C_(1076)H_(1794)N_(322)O_(334)S_(10),分子量为24.91kDa,带正电荷氨基酸残基总数(Lys+Arg)为40,带负电荷氨基酸残基总数(Asp+Glu)为32,脂肪系数为80.64,总平均亲水性系数(GRAVY)为–0.729,不稳定系数为66.17;莲雾SsSOC1蛋白结构不含β-折叠,不属于分泌蛋白与膜结构蛋白,亚细胞定位显示其主要存在于细胞核中,属于不稳定的亲水性碱性蛋白,该蛋白具有MADS_MEF2_like和K-Box保守结构域,同时隶属于MADS超级家族和K-Box超级家族,该结构域的起止氨基酸位点为第3~75位和第88~171位,符合MADS蛋白家族与K-Box家族的典型结构特征;系统进化树分析显示,莲雾SsSOC1序列与油叶蒲桃的同源性最高;通过花序侵染法将SsSOC1基因转化拟南芥,发现35S::SsSOC1表现出早花表型,莲座叶数量比野生型要少。本研究初步确定了SsSOC1基因在成花方面的重要作用,并揭示莲雾遮荫与成花相关的内在调控机理,为莲雾生产提供指导意义,以及为莲雾反季节栽培技术改良提供理论依据。展开更多
基金Project (2008ZE53042) supported by National Aerospace Science Foundation of China
文摘In order to conform to dimensional tolerances, an efficient numerical method, displacement iterative compensation method, based on finite element methodology （FEM） was presented for the wax pattern die profile design of turbine blades. Casting shrinkages at different positions of the blade which was considered nonlinear thermo-mechanical casting deformations were calculated. Based on the displacement iterative compensation method proposed, the optimized wax pattern die profile can be established. For a A356 alloy blade, substantial reduction in dimensional and shape tolerances was achieved with the developed die shape optimization system. Numerical simulation result obtained by the proposed method shows a good agreement with the result measured experimentally. After four times iterations, compared with the CAD model of turbine blade, the total form error decreases to 0.001 978 mm from the orevious 0.515 815 mm.
基金co-supported by the National Natural Science Foundation of China (Nos. 51475374 and 51505387)the Fundamental Research Funds for the Central Universities (No. 3102015ZY087)
文摘As an important index affecting the aerodynamic performance and the structural strength of hollow turbine blades, the wall-thickness precision of the blade is mainly inherited from the positional relationship between the corresponding wax pattern and the internal ceramic core.However, due to locating errors, the actual position of ceramic core is always deviated from the ideal position, which makes it difficult to guarantee the wall-thickness precision of the wax pattern.To solve this problem, a wall-thickness compensation strategy is proposed in this paper. Firstly,based on the industrial computed tomography(ICT) technique and curve matching algorithms, a model reconstruction method is developed, with which the 3D model of a trial wax pattern can be easily constructed. After that, focusing on eliminating the wall-thickness errors of the trial wax pattern, an optimization method for the pose of the ceramic core in the wax pattern is proposed. Then, by mapping the optimal pose of the ceramic core to length adjustments of the locating rods, the wall-thickness errors of the wax pattern can be greatly reduced. A case study is also given to illustrate the effectiveness of the proposed compensation strategy.
文摘The aim of this study is to evaluate the maximum and minimum distances between the model and the cast crown of three techniques using Scanning Electron Microscopy (SEM). Three technique groups were used for this study: group A (control), traditional manual wax patterns;group B, dipping wax patterns;group C, resin patterns made with CAD/CAM. For each group, 10 samples were made using the same model, and then metal cast. Marginal accuracies of the samples were evaluated by performing gap measurements using SEM with a magnification of 1200× (minimum distance). The data were statistically analyzed using the one-way analysis of variance (ANOVA) at the 0.05 significance level. The average (standard deviation) of the minimum distance [μm] was 22.5 (12.1), 9.9 (4.3), and 14.7 (6.6), in groups A, B, and C, respectively. The average standard deviation of gap area [μm2] was 21667.2 (3476.4), 9906.4 (1512.1), and 16048.8 (8123). In the minimum distance comparison, groups A and B (p = 0.006) showed statistically significant results. In the gap area comparison, there was no statistical significance among groups A, B, and C (p = 0.174). The marginal adaptations of all three techniques were within a reported clinically acceptable range of margin.
文摘SOC1(SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1)是植物中的一个开花时间调节因子,属于MADS-box转录因子家族,在植物从营养生长向生殖生长的转变中发挥关键作用。SOC1参与多种生物过程,包括花器官发育、开花时间控制以及对环境刺激和激素信号的响应。本研究通过遮荫和喷施乐斯本的方式对莲雾进行催花处理,统计处理后的叶芽和花芽数量以及成花枝率,同时,利用课题组现有的莲雾转录组进行分析,筛选出调控莲雾开花的候选基因SsSOC1,并通过实时荧光定量PCR技术研究遮荫处理和喷施乐斯本药剂处理下莲雾不同时期和组织中SsSOC1表达量的差异。结果显示:经过遮荫处理的莲雾树体芽点、叶片、叶尖以及叶柄中的SsSOC1基因表达量显著增加,其中叶尖的相对表达量最高。本研究成功克隆了莲雾黑糖芭比品种的SsSOC1基因,并利用生物信息学方法对其进行启动子分析、蛋白理化性质分析、保守功能域的预测和序列比对。结果表明:SsSOC1基因的开放阅读框长度为654 bp,共编码217个氨基酸,其编码蛋白的理论等电点为9.37,分子式为C_(1076)H_(1794)N_(322)O_(334)S_(10),分子量为24.91kDa,带正电荷氨基酸残基总数(Lys+Arg)为40,带负电荷氨基酸残基总数(Asp+Glu)为32,脂肪系数为80.64,总平均亲水性系数(GRAVY)为–0.729,不稳定系数为66.17;莲雾SsSOC1蛋白结构不含β-折叠,不属于分泌蛋白与膜结构蛋白,亚细胞定位显示其主要存在于细胞核中,属于不稳定的亲水性碱性蛋白,该蛋白具有MADS_MEF2_like和K-Box保守结构域,同时隶属于MADS超级家族和K-Box超级家族,该结构域的起止氨基酸位点为第3~75位和第88~171位,符合MADS蛋白家族与K-Box家族的典型结构特征;系统进化树分析显示,莲雾SsSOC1序列与油叶蒲桃的同源性最高;通过花序侵染法将SsSOC1基因转化拟南芥,发现35S::SsSOC1表现出早花表型,莲座叶数量比野生型要少。本研究初步确定了SsSOC1基因在成花方面的重要作用,并揭示莲雾遮荫与成花相关的内在调控机理,为莲雾生产提供指导意义,以及为莲雾反季节栽培技术改良提供理论依据。
