Computation of the Simplest Normal Forms for Resonant Double Hopf Bifurcations System Based on Lie Transform

The simplest normal form of resonant double Hopf bifurcation was studied based on Lie operator. The coefficients of the simplest normal forms of resonant double Hopf bifurcation and the nonlinear transformations in terms of the original system coefficients were given explicitly. The nonlinear transformations were used for reducing the lower- and higher-order normal forms, and the rank of system matrix was used to determine the coefficient of normal form which could be reduced. These make the gained normal form simpler than the traditional one. A general program was compiled with Mathematica. This program can compute the simplest normal form of resonant double Hopf bifurcation and the non-resonant form up to the 7th order.     

水泥混凝土路面脱皮露骨的原因分析及预防措施

本文从施工技术管理方面阐述了水泥混凝土路面脱皮露骨的产生原因及预防措施.     

Effects of condensed water on limestone surfaces in a marine environment

We have evaluated the effects of condensed water on limestone surfaces through a procedure that foresaw the cooling of the samples before their exposition to the open air, so that the condensation phenomena could occur easily. The effects of the condensed water were evaluated by measuring the weight change of the samples, through SEM observations and analysis of the 3-D profile, using laser profilometer. The results show the weak action of condensed water on the stone surface, particularly if compared with that of rain.     

速度攀岩运动员肌肉疲劳的表面肌电信号分析方法

实验表明,速度攀岩运动是非周期性运动,攀岩运动员在速度攀岩的每趟或同一趟的不同时段,他的表面肌电信号都有较大的变化,是显著的非稳定信号。所以,运用表面肌电信号分析速度攀岩运动员的肌肉疲劳问题存在着一定的困难:不能用传统的频阈分析方法去评价相关肌肉的疲劳问题,而只有运用非线性信号分析方法才能较好解决这一问题,然而sEMG非线性信号分析的应用尚属初期探索阶段,有待科研工作者的深入研究。     

船舶近满载液体舱自由液面对稳性影响的修正方法

若考虑船舶液（体）舱内自由液面对稳性的影响，对于非液货舱通常是按装载５０％舱容液体的固定值计算。当液舱（接）近满载时，许多船舶由于缺乏修正资料或方法，其影响值均被看作为零。事实上，对于那些设置有容量大、数量多的液舱的船舶，若将众多近满载液舱对稳性的影响进行叠加，其数值已不容忽视。本文通过数学推导，借助计算机模拟运算，结合计算实例，介绍了一种适应性较强的近满载液舱自由液面对稳性影响的计算方法，具有一定的实用价值。     

个体无氧阈前后股外肌表面肌电图的定量分析

对北京体院体育系20名健康男生，在递增负荷的动力性练习中，个体无氧阈前后股外肌表面肌电图平均功率频率（MPF）及积分肌电图（IEMG）的变化进行了研究。实验发现：1）在递增负荷的练习中，MPF先随负荷递增而上升（增多），而后出现向下（减少）的“拐点”，拐点出现时期与个体无氧阈时期大致相同，MPF所出现的拐点可作为无损测定个体无氧阈的指标。2）IEMG在递增负荷的练习中，一直是逐渐增长的，无非线性增长的拐点出现。反映了运动单位募集是逐步增长的过程，而且发现快、慢运动单位的募集都增加。     

速滑服风致减阻效能评价方法

针对速滑服风致减阻效能的优劣,分析了身着速滑服运动员模型风致阻力的组成,提出了分别基于风洞试验以及材料表面微观几何特征观测的速滑服减阻效能评价方法,并进行速滑服的减阻效能评价试验。试验表明,具有较低的材料表面轮廓算数平均偏差值的速滑服减阻效能优异,试验也相互验证了两种比赛服减阻效能评价方法的可靠性。     

盐碱地改良技术综述与一种新的研究模式展望

我国是一个农业人口大国,耕地和粮食的质量安全及稳定生产,在国民经济发展中具有非常重要的地位。体现农业综合生产能力的重要标志是耕地资源质量问题,其中对盐碱化土壤等中、低产改造利用是一项重要的基础工程,为此我国在农田盐碱地改良利用治理和研究诸多方面付出了不懈的努力,并取得了显著的成效。本文根源于我国盐碱地改良整治技术的发展,对传统的水利改良技术、后起的土壤生物化学改良技术、现代节水灌溉农田水盐调控技术研究内容和效果等进行了综述分析。随着我国多形式节水灌溉技术研究应用和推广,以适应新的灌溉条件下土壤水盐管理利用的新技术理论和方法也在不断呈现,如"土壤水盐定向迁移"和农田土壤"盐分上移地表排"即为近年来我国水利科技人员,创新提出并研究的土壤水盐改良利用新技术理论和解决模式,本文对这一新的技术理论和灌排模式研究内容进行了介绍,并提出展望。     

An examination of the mechanical interaction of drilling slurries at the soil-concrete contact

Evidence gained from previous field tests conducted on drilled shaft foundation shows that using drilling slurries to stabilize a borehole during the construction may influence the interfacial shear strength. This paper deals with an exhaustive study of the effects of drilling slurries at the contact between soil and concrete. This study involved adapting a simple shear apparatus and performing approximately 100 experimental tests on the interaction between two types of soils; clay and sandy clay and five specimens of concrete with different surface shapes. It also involved using bentonite and polymer slurries as an interface layer between soil and concrete. Results showed that an interface layer of bentonite slurry between clay and concrete decreases the interfacial shear strength by 23% and as an interface layer between sandy clay and concrete, bentonite increases interfacial shear strength by 10%. Using polymer slurry as an interface layer between clay and concrete decreases the interfacial shear strength by 17% while using it as an interface layer between sandy clay and concrete increases the interfacial shear strength by 10%. Fur- thermore, the data show that using bentonite and polymer slurry as an interface layer between clay and concrete decreases the sliding ratio by 50% to 60%, while increasing the sliding ratio by 44% to 56% when these are used as an interface layer between sandy clay and concrete.     

田中一光的能剧海报艺术特征探析

日本平面设计大师田中一光设计的戏剧海报作品中,能剧海报独树一帜。能剧海报多以日本传统的能面形象为基本元素,结合理性严谨的方格骨格,采用热情饱满的日本民族色彩,巧妙处理虚实关系,是民族与国际、传统与现代完美结合的典范。