Transnational Mathematics and Movements: Shiingshen Chern, Hua Luogeng, and the Princeton Institute for Advanced Study from World War II to the Cold War

This paper reconstructs,based on American and Chinese primary sources,the visits of Chinese mathematicians Shiing-shen Chern陈省身(Chen Xingshen)and Hua Luogeng华罗庚(Loo-Keng Hua)4 to the Institute for Advanced Study in Princeton in the United States in the 1940s,especially their interactions with Oswald Veblen and Hermann Weyl,two leading mathematicians at the IAS.It argues that Chern’s and Hua’s motivations and choices in regard to their transnational movements between China and the US were more nuanced and multifaceted than what is presented in existing accounts,and that socio-political factors combined with professional-personal ones to shape their decisions.The paper further uses their experiences to demonstrate the importance of transnational scientific interactions for the development of science in China,the US,and elsewhere in the twentieth century.

Hikikomori, a Phenomenon of Social Withdrawal and Isolation in Young Adults Marked by an Anomic Response to Coping Difficulties: A Qualitative Study Exploring Individual Experiences from First- and Second-Person Perspectives

Hikikomori is a recent phenomenon among young adults in which they isolate themselves from social contacts and responsibility for more than 6 months. This problem has assumed epidemic proportions in Japan and has been widely discussed across disciplines. Previous studies have associated hikikomori with a maladaptation to structural change, an emergent mental problem that needs new diagnosis, or an under-diagnosed schizophrenic disorder. Most previous work has adopted a clinical perspective, and there have been no qualitative studies exploring the individual feelings of people suffering from the syndrome. We adopted a qualitative method using a grounded theory approach. Data collection and analysis took place between September 2006 and August 2008. Theoretical sampling included eight informants from snowball sampling and an online observation consisting of 160 online participants. Analysis focused on informants’ first- and second-person experiences of hikikomori. Data analysis revealed one overriding theme: coping difficulties consisting of the two categories stasis and expression. As a result of conflicting demands and reduced autonomy, respondents experienced stasis, which prevented them from moving forward;“hiding” or “avoiding” heightened the expression of their behaviors. This is the first study to explore the in-depth experience of individuals suffering from hikikomori syndrome in a non-clinical setting. We argue that hikikomoriis not a result of asocial behavior, but rather an anomic response to a situation that informants felt powerless to change and from which they could see no way out. We also observed that feelings of hopelessness and relationship fatigue might be overcome by introducing a relaxed social environment that people can control during rehabilitation.

Experimental and Numerical Study of Wave-Induced Long-Shore Currents on A Mild Slope Beach

The long-shore current distribution on a mild slope beach is studied by combining the numerical model and the physical experiment. The experiments of long-shore currents under the action of regular and irregular waves are conducted on mild beaches with different slopes in a wave basin. A numerical model is established, which includes a wave propagation model, a wave breaking model and a long-shore current model. The validity of the numerical model is proved by the comparison of its results with the results of the experimental model. It is concluded that the wave-ioduced long-shore current is influenced significantly by the incident wave height, the wave angle and the beach slope. Its application to the Bohai Bay indicates that the wave-induced currents have the same order of magnitude as the tide currents in the near-shore zone of mill slope beach. In the design of wastewater ouffall locations on a mild-slope beach with shallow water of the Bohai Bay, the position of the outfall should be 10 km away from the shoreline, which is outside of the surf-zone.

Genome-wide association studies of hypertension:Achievements,difficulties and strategies

Estimated from family studies,the heritability of hypertension ranges from 31%to 68%.Linkage studies and candidate gene association studies were once widely used to investigate the genetic mechanisms of hypertension.However,results from these studies could only explain 1%-2%heritability.With the technological advances and subsequently the accomplishment of the Human Genome Project,genome-wide association studies(GWA studies)have been applied to find genome-wide significant signals for many common diseases.Current GWA studies of hypertension have identified dozens of hypertension or blood pressure associated variants.However,different GWA study identified different variants and the results could hardly be replicated in other studies.Therefore,a debate took place on whether GWA studies will unlock the genetic basis of hypertension and whether we shall continue throwing millions of dollars on GWA studies.This review gives a short introduction to the history of genetic study on hypertension and summarizes the current findings for GWA studies of hypertension or blood pressure.Finally,we will discuss that debate and try to find alternative strategies and technologies that may hold a greater chance to make progress in understanding the genetic risk factors of hypertension and blood pressure regulation.

Experimental study of the movement of control fluid in compound perforation

The interaction between the high pressure gas and the control fluid and the movement mechanism of the control fluid in compound perforation were studied by a series of large-scale experiments, where the movement behavior of the control fluid was observed. The curves of measured pressure were analyzed, a mathematical model for the rigid movement of the control fluid was established, and the movement velocity of control fluid was analyzed. Moreover, the velocity from experimental results and velocity from an analytical solution were contrasted. The movement of the control fluid in the initial stage was similar to the rigid movement; however, the propagation of the pressure wave in the control fluid should be taken into account. Experimental results are significant for research on the movement mechanism of control fluid in compound perforation.

The Interpretation of Mathematical Difficulties in Primary School： Which Perspective to Choose？

Research on learning difficulties in mathematics adopts one of two distinct perspectives. According to the first, learning difficulties are due to the intrinsic characteristics of the student. For supporters of the second perspective, those difficulties result from the interaction between the student and the school system. The objective of this study is to test the validity of these two perspectives in interpreting learning difficulties in mathematics among at-risk students. To this end, we collaborated with normally achieving （undiagnosed） and at-risk students. Results show that the second perspective is better suited to the interpretation of learning difficulties in mathematics students

Mathematical Model and Advanced Control for Gas-phase Olefin Polymerization in Fluidized-bed Catalytic Reactors

In this study, the developments in modeling gas-phase catalyzed olefin polymerization fluidized-bed reactors （FBR） using Ziegler-Natta catalyst is presented. The modified mathematical model to account for mass and heat transfer between the solid particles and the surrounding gas in the emulsion phase is developed in this work to include site activation reaction. This model developed in the present study is subsequently compared with well-known models, namely, the bubble-growth, well-mixed and the constant bubble size models for porous and non porous catalyst. The results we obtained from the model was very close to the constant bubble size model, well-mixed model and bubble growth model at the beginning of the reaction but its overall behavior changed and is closer to the well-mixed model compared with the bubble growth model and constant bubble size model after half an hour of operation. Neural-network based predictive controller are implemented to control the system and compared with the conventional PID controller, giving acceptable results.

Developing a Computer Program for Detailed Study of Planing Hull＇s Spray Based on Morabito＇s Approach

Recently, Morabito(2010) has studied the water spray phenomena in planing hulls and presented new analytical equations. However, these equations have not been used for detailed parametric studies of water spray around planing hulls. In this paper, a straight forward analysis is conducted to apply these analytical equations for finding the spray geometry profile by developing a computer program based on presented computational process. The obtained results of the developed computer program are compared against existing data in the literature and favorable accuracy is achieved. Parametric studies have been conducted for different physical parameters. Positions of spray apex are computed and three dimensional profiles of spray are examined. It is concluded that spray height increases by an increase in the speed coefficient or the deadrise angle. Ultimately, a computational process is added to Savitsky's method and variations of spray apex are computed for different velocities. It is shown that vertical, lateral, and longitudinal positions of spray increase as the craft speed increases. On the other hand, two new angles are defined in top view and it is concluded that they have direct relation with the trim angle. However, they show inverse relation with the deadrise angle.

Improvements to the fuzzy mathematics comprehensive quantitative method for evaluating fault sealing

Fuzzy mathematics is an important means to quantitatively evaluate the properties of fault sealing in petroleum reservoirs.To accurately study fault sealing,the comprehensive quantitative evaluation method of fuzzy mathematics is improved based on a previous study.First,the single-factor membership degree is determined using the dynamic clustering method,then a single-factor evaluation matrix is constructed using a continuous grading function,and finally,the probability distribution of the evaluation grade in a fuzzy evaluation matrix is analyzed.In this study,taking the F1 fault located in the northeastern Chepaizi Bulge as an example,the sealing properties of faults in different strata are quantitatively evaluated using both an improved and an un-improved comprehensive fuzzy mathematics quantitative evaluation method.Based on current oil and gas distribution,it is found that our evaluation results before and after improvement are significantly different.For faults in＂best＂and＂poorest＂intervals,our evaluation results are consistent with oil and gas distribution.However,for the faults in＂good＂or＂poor＂intervals,our evaluation is not completelyconsistent with oil and gas distribution.The improved evaluation results reflect the overall and local sealing properties of target zones and embody the nonuniformity of fault sealing,indicating the improved method is more suitable for evaluating fault sealing under complicated conditions.

Optimization Study on a Single-cylinder Compressed Air Engine

The current research of compressed air engine（CAE） mainly focused on simulations and system integrations. However, energy efficiency and output torque of the CAE is limited, which restricts its application and popularization. In this paper, the working principles of CAE are briefly introduced. To set a foundation for the study on the optimization of the CAE, the basic mathematical model of working processes is set up. A pressure-compensated valve which can reduce the inertia force of the valve is proposed. To verify the mathematical model, the prototype with the newly designed pressure-compensated intake valve is built and the experiment is carried out, simulation and experimental results of the CAE are conducted, and pressures inside the cylinder and output torque of the CAE are obtained. Orthogonal design and grey relation analysis are utilized to optimize structural parameters. The experimental and optimized results show that, first of all, pressure inside the cylinder has the same changing tendency in both simulation curve and experimental curve. Secondly, the highest average output torque is obtained at the highest intake pressure and the lowest rotate speed. Thirdly, the optimization of the single-cylinder CAE can improve the working efficiency from an original 21.95% to 50.1%, an overall increase of 28.15%, and the average output torque increases also increases from 22.047 5 N · m to 22.439 N · m. This research designs a single-cylinder CAE with pressure-compensated intake valve, and proposes a structural parameters design method which improves the single-cylinder CAE performance.

Open Approach-Based Subject Matter： A New Aspect of Mathematical Activity Fostering Students＇ Creativity

This study compares the subject matter appeared on traditional Thai textbooks and Japanese textbooks and analyzes how extension and integration sequence on Japanese textbooks evokes students＇ mathematical creativity. The data were collected from the series of four lessons in the fifth grade by teaching experiment methodology conducted following the professional development project implemented lesson study and open approach in Thailand. The results show that extension and integration sequence is an appropriate subject matter to generate lesson for problem-solving classroom. The sequence of lesson leads students to excitement, curiosity, confidence and intimacy in mathematics that are powerful effects of mathematical creativity. Students can produce the different and various ways to solve problems that indicate their divergent thinking.

Suggestion of global model for carob batch fermentation to produce bioethanol

Modelling of carob batch fermentation is established basing on mass transfer balances. The modelling treats the reaction kinetics of substrate （S）, the micro-organisms （X） and the ethanol （E）. Nine models are taken from the literature to describe specific organism growth rate and specific ethanol development rate. These models treat all types of fermentation. The Phisalapbong et al. model and the Ghose and Tyagi model show the best fit of the experimental data. This affirms that the batch fermentation of carob is conducted with substrate and/or ethanol inhibition. Some simulations and relationships （X = f（S）, E = f（S）） are obtained from the Phisalaphong et al. model. Those simulations show a lot of important and useful results of carob batch fermentation process.

A Longitudinal Study of the Effects of Family Background Factors on Mathematics Achievements Using Quantile Regression

Quantile regression is gradually emerging as a powerful tool for estimating models of conditional quantile functions, and therefore research in this area has vastly increased in the past two decades. This paper, with the quantile regression technique, is the first comprehensive longitudinal study on mathematics participation data collected in Alberta, Canada. The major advantage of longitudinal study is its capability to separate the so-called cohort and age effects in the context of population studies. One aim of this paper is to study whether the family background factors alter performance on the mathematical achievement of the strongest students in the same way as that of weaker students based on the large longitudinal sample of 2000, 2001 and 2002 mathematics participation longitudinal data set. The interesting findings suggest that there may be differential family background factor effects at different points in the mathematical achievement conditional distribution.

循证视域下小学数学听评课教研活动实施的个案研究

基于循证教研视角,以北京市A小学数学学科教研组为个案,采用访谈法、观察法和实物分析法,探讨教师的听评课教研活动现状。结果发现,听评课教研活动存在过程清晰但形式松散、要素健全但流于浅表等问题,如活动主题未契合教师现实需求、教师缺乏基于问题和围绕证据的专业合作等。这些问题主要是由教研活动主题需求错位,教师证据意识匮乏、循证能力薄弱,制度文化抑制以及缺乏专家引领等引起。建议:优化流程,明晰听评课的可视化路径;调研教研需求,提高教师的批判反思能力;促进教师树立循证意识,寻找证据观照;搭建循证合作支持系统。

基于D.H.Jonassen建构主义学习环境设计模型的探索研究

D.H.Jonassen建构主义学习环境教学设计模型包括:设计问题、相关实例、信息资源、认知工具、会话与协作工具、社会背景支持6个方面的内容,相应的6个环节是:确定学习主题、创设教学情境、信息资源设计、自主学习设计、协作学习环境设计和学习效果评价设计.CLE模型的3种教学策略是:建模策略、教练策略和支架策略.在数学教学中,运用该模型,可更好地发挥计算机辅助教学的优势.

Casson流体管流速度分布及温度分布研究

结合Casson流体的本构方程、力平衡关系式及非牛顿流体能量方程,得出了Casson流体管流速度分布及温度分布。研究结果表明,由于Casson屈服应力τ_c的作用,管中心存在柱塞流动,柱塞的半径γ_0与τ_c成正比,与△P/L成反比,柱塞的速度μ_0随τ_c的增大而减小。柱塞内的温度一致,从柱塞边界到管壁,温度逐渐减小,而且越靠近管壁,温度降低幅度越小。

基于综合难度模型的新高考数学试题评析——以2021—2024年新高考Ⅰ卷、Ⅱ卷为例

根据高考数学试题的命题立意,对现有数学高考试题综合难度模型进行调整,从背景因素、是否含参、运算水平、推理能力、知识含量、思维方向、认知水平、新颖水平等8个因素,对2021—2024年新高考Ⅰ卷、Ⅱ卷数学试题的整体难度、知识主题难度、数学题型难度展开分析。结果表明:近4年新高考数学试题综合难度基本稳定,新高考Ⅰ卷难度略高于Ⅱ卷;在知识主题上,函数难度略高于几何与代数,大幅高于概率与统计,预备知识难度最低;解答题难于多选题,填空题次之,单选题最易。基于此,建议进一步强化试题情境创设,更好地贯彻落实基于情境活动的命题要求;聚焦新颖试题形式,着力发展学生的创新意识与综合素质;重视知识融合考查,整合学科知识主题,实现知识模块的交汇关联。

学业情绪视域下个性化数学作业对学生影响的研究

数学是一门逻辑性强、难度大的学科,符合学生个性发展的数学作业会对学生学习和心理发展起事半功倍的效果。为探究个性化数学作业对学生学业情绪的影响机制,研究针对蚌埠市Y中学200名学生进行调查得出主要研究结论:(1)学生对个性化数学作业持积极态度,不存在性别差异。(2)学生的作业态度和认识、完成方式、评价与积极学业情绪呈正相关,作业量和难易程度呈负相关。(3)通过回归分析发现,作业类型对学业情绪没有影响。最后基于研究结果从学业情绪视角提出提升个性化数学作业的建议,为助力个性化数学作业提供实践借鉴。

Research on Long Stroke Moving Secondary Permanent Magnet Linear Eddy Current Brake

In this paper,a long stroke moving secondary permanent magnet linear eddy current brake is proposed.Without exciting coils,the permanent magnet eddy current brake possesses the advantage of saving copper and better reliability.The topology and operating principle are presented.The mathematical model was derived with the layer theory.The braking force characteristic was analyzed using the finite element method.The structural parameters of the long stroke moving secondary permanent magnet linear eddy current brake were studied by referring the design progress of the other types of eddy current brakes.Finally,a prototype of long stroke moving secondary permanent magnet linear eddy current brake was built and tested,and the experimental result verifies the correctness of the above analysis.

数学学科核心素养导向下的教育数学实证研究

教育数学实验是中国教育改革的重要组成部分,学生的数学学科核心素养发展状况是其改革实验效果的重要衡量指标之一.研究选取初中数学核心素养评价框架,对邛崃市教育数学实验进行评价研究,分析该实验对学生数学核心素养发展的影响.基于所选框架对该市2017级初三第二次诊断试卷考查的数学核心素养进行分类.根据学生核心素养的得分,对比分析该市3672名初三学生与93名教育数学实验班学生数学核心素养的发展状况.研究发现:该市初三学生的整体数学核心素养发展不平衡,特别是在数学建模、逻辑推理素养上不合格比例较高;教育数学体系下的实验组核心素养发展情况普遍优于该市整体水平,且其发展更为均衡.结论说明教育数学可促进学生数学核心素养的普遍均衡发展,实验风险可控,适合大规模普及.