Fourth branchial arch defect in a Welsh section A pony mare

Fourth branchial arch defect is a term used to describe a syndrome of congenital defects affecting the extrinsic structures of the larynx, due to a failure of development of structures that derive from the fourth branchial arch. This Case Report describes a 6-year-old Welsh section A mare presented for investigation of a chronic cough that was exacerbated on exercise. A fourth branchial arch defect was identified on resting upper airway endoscopy, with dorsal pharyngeal collapse evident on dynamic respiratory endoscopy, although full abduction of both the left and right arytenoid could be achieved and maintained at exercise.     

西吉县设施拱棚不同茬口效益比较研究

试验设5类种植模式,通过比较表明设施拱棚各种种植模式都充分发挥设施的春提早、秋延后作用,提高土地及光热利用效率,显著增加单位面积的产出,每公顷产值都超过15万元。其中采用"早熟马铃薯-芹菜-菠菜"模式,土地及光热利用效率和产值最高,适宜在西吉及宁南山区推广应用。     

Simplified Method for Evaluating the Elastic Dynamic Instability of the Long Span Arch Bridge

Based on the sense of Liapunov dynamic stability and the features of elastic buckling of arch bridge, and using the static buckling eigenvalue as well as linear time history analysis result, a simplified method for evaluating the elastic dynamic instability was developed from the so called “dynamic eigenvalue method” that needs to extract the minimum buckling eigenvalues step by step under the whole earthquake excitation. The presented method was compared and validated to be efficient and accurate via a case study, and therefore it could be used as a more effective method to study the dynamic stability issue of long span arch bridges and other civil engineering structures.     

Aerostatic stability analysis of long span half-through arch bridges

The main arch of a long-span arch bridge is a compression member. The static wind loads on the bridge not only causes changes of dynamic characters, but also leads the structure to collapse or buckling. Especially, when the arch bridge has longer span and less lateral braces,its stability is much different from the long span cable-stayed bridges and suspension bridges. This paper takes Chongqing Caiyuanba Yangzi River Bridge as a typical example and conducted the wind section tunnel tests. The displacement response of the bridge is obtained and its yield and static stability mechanism under static wind is analyzed. The results show that those factors, such as initial attack angle of the static wind, material yield strength and the static forces coefficients, have great effects on the aerostatics stability of a long span half-through arch bridge.     

洞坪拱坝泄洪随机振动分析

采用三维有限元随机振动法对洞坪拱坝泄洪诱发振动进行了较为深入的研究。分别探讨了设计洪水和校核洪水情况下洞坪拱坝泄洪期间的振动响应特征和规律，考察了拱坝的抗振安全性，进而探讨提高洞坪拱坝抵抗泄洪振动的工程措施。     

简易拱棚仓的建设与使用

介绍了一种简易、经济、实用的拱棚仓。其储粮效果、仓容、建造、管理费用都优于过去的席Ｘｕｅ囤。     

对承重窗间墙过梁下砌体的局压承载力计算的探讨

根据混合结构承重窗间墙窗过梁下的局压砌体的内拱效应、局压强度、受荷面积不同于一般楼盖梁端局压砌体的特点 ,对其承载力计算公式提出探讨并作修正 ,较好地反映实际情况 ,同时需作进一步试验和研究     

Dynamics research of wind turbine gearbox with herringbone planetary gear

Based on the method of gear system dynamics and Lagrange equation, a translational-rotational coupling dynamic model of the herringbone planetary gear sets is built and dynamic analysis is carried out. The analysis results have guiding meanings for the design of herringbone planetary gear transmission system. Herringbone gear is treated as two helical gears in the model, and gear train elastic coupling, load inertia and stagger angle between the left and right helical gears is considered. The load sharing coefficients of the system are obtained through calculation, and the impact of stagger angle and coupling torsional stiffness between the left and the right helical gears on the load sharing characteristic is analyzed. The analysis results show that when stagger angle is π/2, the load sharing coefficients are the best, and coupling torsional stiffness between the left and the right helical gears has litter influence on the load sharing coefficients.     

Wind Tunnel Tests of Long Span Half - through Arch Bridge Section Model

Wind induced vibration is one of the main control factors in the Long span bridge structure design. The wind tunnel tests for measuring the static wind forces on the bridge girder and the section model wind tunnel dynamic testing for Caiyuanba Yangtze River Bridge in Chongqing are introduced in this paper. The wind tunnel testing for measuring static wind forces and vortex- induced vibration test on the arch are introduced taking account of the influence between two arches. The main contents and outcomes of testing are presented. It is indicated that the bridge girder has excellent wind stability and the arch mechanical characters are rather complicated. The drag force on the hind arch varied a lot because of the font arch interference on the wind flow. The drag force on the hind arch will be negative when two arches are close to each other. It increases with the space of two arches. The results of testing will give the data of buffeting and vortex - induced vibration and flutter analysis of the bridge.