扣件式钢管支模架体系倒塌事故原因分析及相关问题的探讨

通过对支模架倒塌原因分析,以及对规范模板支撑架计算中几个问题的探讨,提出模板工程设计应注意的问题和对规范相关条文的修改建议。     

3K形钢管节点静力工作性能的试验研究

分析了节点各杆最不利受力状况试验结果，测试了各杆在最不利荷栽作用下的应力状况，揭示了节点的受力性能，为3K形钢管节点的应用提供准确的试验数据。     

Effect of tadalafil in chronic renal failure rabbits: relevance to erectile dysfunction

It is of great importance to investigate an effective and reliable medication against chronic renal failure (CRF)-related erectile dysfunction (ED), which aims to improve patients’ life qualities. The concentrations of cyclic guanosine monophosphate (cGMP) in the corpus cavernosal smooth muscle of both CRF and control rabbits were measured. The effects of various concentrations of tadalafil, papaverine, and sodium nitroprusside on the relaxation responses of corpus cavernosal smooth muscle pre-contracted with phenylephrine in CRF rabbits were observed. There was significant difference in the concentration of cGMP between CRF and control rabbits (P<0.01). Tadalafil had the greatest impacts on CRF rabbits when given the same concentration of papaverine or sodium nitroprusside and particularly significant differences were identified under the concentration levels of 10⁻⁵ and 10⁻⁴ mol/L (P<0.01). The results suggest that the cGMP concentrations of the corpus cavernosum had been greatly reduced in CRF rabbits compared with control rabbits and that tadalafil may be an ideal medication for use in the treatment of CRF-related ED.     

两种家兔急性肾功能衰竭模型复制的方法学比较

目的:探讨两种家兔急性肾功能衰竭(ARF)模型的方法学差异.方法:皮下注射1%HgCl2(1.5ml/kg.bw,H组)、肌肉注射50%甘油(5.6ml/kg.bw、8ml/kg.bw、10ml/kg.bw三种剂量,依次为G1组、G2组、G3组)复制家兔ARF模型,测定24h和48h血清尿素氮(BUN)和肌酐(Cre)水平,观察比较各组模型复制的成功率、存活率及稳定性.结果:G1、G2两组不能成功复制ARF模型;G3组BUN、Cre较H组降低(P＜0.05).但G3组的存活率及稳定性均显著高于H组(P＜0.05).结论:两种模型复制方法各有优缺点,应根据不同研究目的选择相应的模型.     

Approach for analyzing the ultimate strength of concrete filled steel tubular arch bridges with stiffening girder

A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders is investigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.     

倮裹钢管混凝土拱桥施工控制

结合钢管混凝土拱桥施工控制的实例，探讨钢管混凝土拱桥施工控制的主要内容与控制方法，对监控结果进行分析，并对施工中需注意的事项提出几点建议。     

K型铸钢节点刚域研究

本文利用ANSYS对K型铸钢节点与钢管相贯节点在节点转动刚度上进行了对比,K型铸钢节点存在刚域,既不是铰接,也不是简单刚接,本文提出了一种计算K型铸钢节点刚域长度的方法。     

Radiographic anatomical insights into mechanism of lower calyceal stone evacuation following ESWL

This study was aimed to elucidate whether there is significant relationship between the lower calyceal anatomy and stone evacuation following extracorporeal shock wave lithotripsy(ESWL). From April 1995 to November 1999, 145 patients with lower caliceal stones underwent ESWL with Storz Modulith SL20 lithotriptor. The pelvicalyecal angle, lower pole infundibular length and width, and lower pole calyceal pattern of the stone-bearing calyx were measured on pre-ESWL intravenous urograms. Abdominal plain film and ultrasonography taken of all patients at the 3-month followup showed that the overall stone-free rate was 65% after 3 months. The stone-free rate was significantly correlated to the radiographic anatomical factor, 94% in patients with a pelvicalyceal angle of 90 degrees or greater, 57% in those with less than 90 degrees pelvicalyceal angle; 80% in those with infundibular length of 30 mm or less, 59% in those with infundibular length greater than 30 mm; 73% in those with infundibular width greater than 4 mm, 48% in those with infundibular width of 4 mm or less; 85% in those with a simple calyceal pattern and 41% in those with a complex one. These findings suggest that the 4 radiographic anatomical factors of the lower pole calyx (pelvicalyceal angle, infundibular length and width and calyceal pattern) play an important role in stone evacuation after ESWL. Pelvicalyceal angle of 90 degrees or greater, infundibular length of 30 mm or less and width greater than 4 mm, and simple calyceal pattern are respectively noted to relate to an improved stone-free status. In contrast, an acute pelvicalyceal angle, long infundibular length and narrow infundibular width and complex calyceal pattern are individually unfavorable factors for stone emptying following ESWL.     

自由基清除剂在运动后对血浆LpO和肾组织结构的影响

运动后1小时测定SD鼠血浆丙二醛(MDA),并观察肾组织超微结构,发现血浆MDA上升至13.325nmol/ml,肾上皮足突广泛融合(p≈0.05)、线粒体肿胀破裂。经用VE和VC血浆MDA上升值下降至11.868nmul/ml(p<0.05),加用GSH后血浆MDA上升值下降至9.592nmol/ml(p<0.05);肾形态变化减弱、足突变化(p>0.05)、线粒体完整。提示合用GSH、VE和VC可降低血浆MDA上升值,保护肾脏。     

力竭性游泳运动对大鼠血尿酸等指标的影响

90～100日龄 Wisten雄性大 21只,随机分成 3 组,并在同样条件下饲养,其中一组在安静条件下处死,另一组在力竭性游泳2小时后处死,第三组在力竭性游泳后立即处死.然后检测它们的血乳酸、血肌酐、血尿酸水平,结果显示力竭性运动后血乳酸增多以及肾血流量和肾过滤率下降是血尿酸水平上升的主要原因。