A study of airfoil parameterization,modeling, and optimization based on the computational fluid dynamics method

An excellent airfoil with a high lift-to-drag ratio may decrease oil consumption and enhance the voyage. Based on NACA 0012, an improved airfoil is explored in this paper. The class/shape function transformation has been proved to be a good method for airfoil parameterization, and in this paper it is modified to improve imitation accuracy. The computational fluid dynamics method is applied to obtain numerically the aerodynamic parameters of the parameterized airfoil, and the result is proved credible by comparison with available experimental data in the open literature. A polynomial-based response surface model and the uniform Latin hypercube sampling method are employed to decrease computational cost. Finally, the nonlinear programming by quadratic Lagrangian method is utilized to modify the multi-island genetic algorithm, which has an improved optimization effect than the method used on its own. The obtained result shows that the modified class/shape function transformation method produces a better imitation of an airfoil in the nose and tail regions than the original method, and that it will satisfy the tolerance zone of the model in a wind tunnel. The response surface model based on the uniform Latin hypercube sampling method gives an accurate prediction of the lift-to-drag ratio with changes in the design variables. The numerical result of the flow around the airfoil shows reasonable agreement with the experimental data graphically and quantitatively. Ultimately, an airfoil with better capacity than the original one is acquired using the multi-island genetic algorithm based nonlinear programming by quadratic Lagrangian optimization method. The pressure contours and lift-to-drag ratio along with the attack angle have been compared with those of the original airfoil, and the results demonstrate the strength of the optimized airfoil. The process for exploring an improved airfoil through parameterization to optimization is worth referencing in future work.     

旅游对民族旅游地文化影响探析

跨学科研究是旅游研究中一种重要的手段,文章从社会学、传播学和旅游学三角度出发,主要就跨民族文化传播、文化冲突和文化控制三方面,分析了民族旅游目的地因旅游产生的正、负影响,进而提出了加强法制建设、加强教育、加强舆论导向和发挥群体作用等具体措施,以图促进民族旅游的健康发展和民族旅游目的地文化的进步.     

词汇语义探讨

语义问题是词汇研究的重心。本从词定义的模糊性、词的语义单位及单个词内的语义之间的关系及组织等三方面着手对词汇语义问题进行了探讨。     

Chinese middle school teachers’ preferences regarding performance evaluation measures

Teacher performance evaluation currently is receiving unprecedented attention from policy makers, scholars, and practitioners worldwide. This study is one of the few studies of teacher perceptions regarding teacher performance measures that focus on China. We employed a quantitative dominant mixed research design to investigate Chinese teachers’ preferences for teacher performance measures and the possible reasons for their preferences. Considering the quantitative results, the surveyed Chinese teachers identified fulfillment of additional roles, collaboration with faculty and staff, and students’ test scores as the most important measures for performance evaluation. Qualitatively, the most important measures that the surveyed teachers reported were the teacher’s morality, workload, and students’ test scores.     

手工教学策略新探

当今,虽然对于"创造教育"的研究早已成为不"时尚"的课题,人们对此也做过许多有关方面的探索研究,但倘若我们冷静反思当前高职高专学院美术学科手工课程教学的现状,便会发现其教学策略仍然停滞在长期以来一直沿用的在"继承"的基础上谈"设计"的模式上,仍存在着对"创造"内涵认识的浅表化及创造技术的单一化。我们只有以宏观的角度、全新的现代"创造学"科学理论重新审视与指导"创造教育,"把教育目标锁定在引导学生自主研究如何对传统项目进行全方位的"技术革新"上,把培养学生的开拓创新能力摆在第一位,才能真正从实质上实现拓宽学生的思路,全方位激发其创造灵感,使其思维更富有创见性。     

The effect of 14 weeks of vitamin D3 supplementation on antimicrobial peptides and proteins in athletes

Heavy training is associated with increased respiratory infection risk and antimicrobial proteins are important in defence against oral and respiratory tract infections. We examined the effect of 14 weeks of vitamin D₃ supplementation (5000 IU/day) on the resting plasma cathelicidin concentration and the salivary secretion rates of secretory immunoglobulin A (SIgA), cathelicidin, lactoferrin and lysozyme in athletes during a winter training period. Blood and saliva were obtained at the start of the study from 39 healthy men who were randomly allocated to vitamin D₃ supplement or placebo. Blood samples were also collected at the end of the study; saliva samples were collected after 7 and 14 weeks. Plasma total 25(OH)D concentration increased by 130% in the vitamin D₃ group and decreased by 43% in the placebo group (both P = 0.001). The percentage change of plasma cathelicidin concentration in the vitamin D₃ group was higher than in the placebo group (P = 0.025). Only in the vitamin D₃ group, the saliva SIgA and cathelicidin secretion rates increased over time (both P = 0.03). A daily 5000 IU vitamin D₃ supplement has a beneficial effect in up-regulating the expression of SIgA and cathelicidin in athletes during a winter training period, which could improve resistance to respiratory infections.     

武术俱乐部视域下武德对学生传统美德的寓理教育

采用文献资料法、访谈调研法、实践教学法、逻辑分析法等方法,探讨中华武德对学生传统美德的教育作用。结果表明:中华武德的核心观念是仁、义、礼、智、信、勇,蕴含着仁慈、爱国、爱民、重义、守礼、和谐、谦让、中正、诚实、守信、忠勇、报国等传统美德,通过校内外武术俱乐部进行中华武德交流,对学生的传统美德修养具有良好的寓理教育作用,能促进学生美德修养的自我养成。     

如何开发高校学生寝室文化建设的综合功能

高校寝室文化就是高校中最具影响力的文化之一,在改革大潮滚滚而来之下,学生寝室文化被赋予了一种全新的内涵,大学生在与日常生活环境的互动关系中应该体现出新的精神追求和价值取向,同时应该创造一种具有时代气息的新生活.这种新生活将成为学生寝室文化的时代定位,也是高校如何调整和加强对学生寝室的管理、育人和服务功能的依据.     

Bedingungen der Bindungswirkung inkrementeller Normen in Fußballvereinen

Sports clubs depend on the pooling of resources by their members. The supportive distribution of the resources within a club is facilitated in particular by the effectiveness of incremental standards. A basic prerequisite for a fair distribution of resources is a minimum of community spirit among the members. Based on a nationwide survey of football clubs and an ordinal logistic regression model, factors were determined that reflect the extent of the community spirit within a club. The opening up of the club by payment to players and perceived problems with acquiring and binding of volunteers are associated with a reduction of community spirit. In contrast, the perception that the club activities can be continued in the long term shows a positive correlation to a highly developed community spirit.     

A channel distortion model for video over lossy packet networks

Error-resilient video communication over lossy packet networks is often designed and operated based on models for the effect of losses on the reconstructed video quality. This paper analyzes the channel distortion for video over lossy packet networks and proposes a new model that, compared to previous models, more accurately estimates the expected mean-squared error distortion for different packet loss patterns by accounting for inter-frame error propagation and the correlation between error frames. The accuracy of the proposed model is validated with JVT/H.264 encoded standard test sequences and previous frame concealment, where the proposed model provides an obvious accuracy gain over previous models.