改进的青光眼白内障联合手术——垂直小梁切除人工晶状体植入术

目的 探讨巩膜隧道小切口内改良垂直小梁切除巩膜翻转联合人工晶状体植入术治疗青光眼合并白内障的治疗效果。方法 对 18例 2 4眼青光眼合并白内障采用经角巩膜隧道小切口完成垂直小梁切除深层巩膜条翻转引流联合非超声乳化白内障摘出人工晶状体植入术 ,术后观察视力、眼压、滤过泡及并发症情况。结果 术后随访 3～ 18月 ,视力大于 0 3者 2 1眼 ,占 87 5 % ,眼压控制在正常范围内 (小于 2 0 5 5mmHg) ( 1mmHg =0 .13 3kPa) 18眼 ,占 75 %。结论 该手术治疗青光眼合并白内障 ,具有良好的控制眼压和恢复有用视力的效果。

“垂直架梁”样双接骨板结合空心螺钉治疗肱骨髁间骨折(附11例分析)

目的:评价"垂直架梁样"双接骨板结合空心螺钉治疗肱骨髁间骨折的治疗效果和技术特点。方法:自2006年3月～2008年4月应用此方法治疗肱骨髁间骨折11例,其中男9例,女2例,年龄19～55岁,平均33岁。结果:平均手术时间160分钟,平均出血量240ml,所有病例获得随访,随访时间6～26个月,所有病例获得骨性愈合,无内固定物松动、脱出或断裂,肘关节功能依特殊外科评分方法(HSS):优3例,良5例,可2例,差1例。结论:垂直架梁样双接骨板结合空心螺钉治疗肱骨髁间骨折可以达到坚强固定,早期功能锻炼的目的,符合生物力学的要求,可获得比较满意的临床疗效。

亚临界锅炉刚性梁布置原则及结构特点

亚临界锅炉的刚性梁一般采用绕带式刚性梁系统。绕带式刚性梁系统,是指前后及两侧墙四根刚性梁围绕管墙四周形成一道密封刚性梁环,并且刚性梁基本都为简支梁结构。亚临界刚性梁由垂直刚性梁和水平刚性梁及各种刚性梁附件组成。

潜艇内部平面舱壁设计研究

对国内潜艇内部平面舱壁的设计现状进行了分析研究,补充与完善了水平大梁与垂直梁肘板处的弯矩与剪力的公式。采用优化设计方法完成了对舱壁板、水平大梁、水平大梁肘板、垂直梁、垂直梁肘板的全部设计计算,使内部舱壁的设计更合理、更科学。对舱壁板厚度的设置提出了控制条件,分析了舱壁板厚度、水平大梁腹板厚度、垂直梁腹板厚度、垂直梁间距对舱壁总重的影响。

Train-induced vibration on elevated railway station

Results of in-situ vibration measurement carried out at Tianjin West Elevated Railway Station which has the trains running on the station structure were reported. The main excitation source is the train passing through the station. Vibration measurements were recorded in the vertical direction of the supporting track beam, the platform and the steel truss beam of the waiting hall, as well as in the vertical, longitudinal and transverse directions of the roof arch base of the station. Acceleration time responses were obtained. The maximum value, vibration level and one-third octave band RMS spectra of the measured accelerations were studied. The propagation of vibration in different structural floors was discussed. The influence of train speed, distance to the vibration source and the type of train on the structural vibration were analyzed. Results show that the vibration level increases with the train speed, while it attenuates with the distance to the track. Furthermore, the vibration responses of different structural floors were compared, and it is noted that the vertical vibration of the bottom slab of the platform is most severe and the transverse vibration of the roof arch base is the smallest. The results provide reference on the vibration characteristics and vibration energy distribution of this type of "Train on building frame" system used as an elevated railway station.

Numerical calculation on solar temperature field of a cable-stayed bridge with U-shaped section on high-speed railway

Based on transient temperature field theory of heat conduction, the solar temperature field calculation model of U-shape sectioned high-speed railway cable-stayed bridge under actions of concrete beams and ballast was established. Using parametric programming language, finite element calculation modules considering climate conditions, bridge site, structure dimension and material thermophysical properties were compiled. Six standard day cycles with the strongest yearly radiation among the bridge sites were selected for sectional solar temperature field calculation and temperature distributions under different temperature-sensitive parameters were compared. The results show that under the influence of sunshine, U-shape section of the beam shows obvious nonlinear distribution characteristics and the maximum cross-section temperature difference is more than 21℃; the ballast significantly reduces sunshine temperature difference of the beam and temperature peak of the bottom margin lags with the increase of ballast thickness; the maximum cross-section vertical temperature gradient appears in summer while large transverse temperature difference appears in winter.

基于SEVNDB试样岩石复合断裂韧度测试:数值分析与标定

提出了一种利用非对称三点弯曲加载下的单边垂直切槽深梁试件(SEVNDB)开展岩石Ⅰ-Ⅱ复合断裂韧度测试方法。通过有限元法对试件的无量纲应力强度因子进行了数值分析与标定,研究了无量纲应力强度因子YⅠ、YⅡ及无量纲T应力T*与裂纹长度a、支座间距S1、S2之间的关系,定量刻画了实现纯Ⅱ型加载对应的裂纹长度a、支座间距(S1和S2)数值。研究结果表明,该方法在不改变试样裂缝倾角的前提下,通过调整裂缝长度a和支座间距S1、S2,即可方便地实现从纯Ⅰ型到纯Ⅱ型任意复合度载荷作用下的岩石断裂韧度测试。

Damage alarming of long-span suspension bridge based on GPS-RTK monitoring

Structure damage identification and alarming of long-span bridge were conducted with three-dimensional dynamic displacement data collected by GPS subsystem of health monitoring system on Runyang Suspension Bridge.First,the effects of temperature on the main girder spatial position coordinates were analyzed from the transverse,longitudinal and vertical directions of bridge,and the correlation regression models were built between temperature and the position coordinates of main girder in the longitudinal and vertical directions;then the alarming indices of coordinate residuals were conducted,and the mean-value control chart was applied to making statistical pattern identification for abnormal changes of girder dynamic coordinates;and finally,the structural damage alarming method of main girder was established.Analysis results show that temperature has remarkable correlation with position coordinates in the longitudinal and vertical directions of bridge,and has weak correlation with the transverse coordinates.The 3%abnormal change of the longitudinal coordinates and 5%abnormal change of the vertical ones caused by structural damage are respectively identified by the mean-value control chart method based on GPS dynamic monitoring data and hence the structural abnormalities state identification and damage alarming for main girder of long-span suspension bridge can be realized in multiple directions.

Vertical load capacities of roof truss cross members

Trusses used for roof support in coal mines are constructed of two grouted bolts installed at opposing forty-five degree angles into the roof and a cross member that ties the angled bolts together. The load on the cross member is vertical, which is transverse to the longitudinal axis, and therefore the cross member is loaded in the weakest direction. Laboratory tests were conducted to determine the vertical load capacity and deflection of three different types of cross members. Single-point load tests, with the load applied in the center of the specimen and double-point load tests, with a span of 2.4 m, were conducted. For the single-point load configuration, the yield of the 25 mm solid bar cross member was nominally 98 kN of vertical load, achieved at 42 cm of deflection. For cable cross members, yield was not achieved even after 45 cm of deflection. Peak vertical loads were about 89 kN for 17 mm cables and67 kN for the 15 mm cables. For the double-point load configurations, the 25 mm solid bar cross members yielded at 150 kN of vertical load and 25 cm of deflection. At 25 cm of deflection individual cable strands started breaking at 133 and 111 kN of vertical load for the 17 and 15 mm cable cross members respectively.

Safety threshold of high-speed railway pier settlement based on train-track-bridge dynamic interaction

This paper presents a method to determine the safety threshold of bridge pier settlement in high-speed railways.An analytical expression of the mapping relationship between the pier settlement and the rail deformation is derived theoretically for the double block ballastless track-bridge system.By adopting the superposition of the track random irregularity and the rail deformation caused by the pier settlement as the excitation inputs,the variations of vehicle dynamics indices with pier settlement are comparatively analyzed.Then,the safety threshold of the bridge pier settlement is obtained according to the limit of vehicle running safety and ride comfort indices of the high-speed trains.Results show that the dynamics indices of different trains have different sensitivities to the pier settlement,and the train CRH2C is the most sensitive one among all the types of Chinese high-speed trains.When passing through the bridges in common span with pier settlement at the speed of 250–350 km/h,the trains suffer the low-frequency excitations,and the vertical acceleration of car body is most sensitive to the pier settlement of all the dynamics indices.When the car body vertical acceleration just exceeds the allowable limit,the critical settlement value is 23.4 mm,which is much bigger than the pier differential settlement limit in the current code for Chinese high-speed railways.