崇启大桥曲线形变截面钢箱梁梁段制造工艺技术

介绍了崇启大桥曲线形变截面钢箱梁梁段在制造过程中所采用的制造工艺技术,为同类型桥梁制造提供参考。     

对赛场噪声影响平衡木比赛动作稳定性的研究

平衡木比赛对运动员动作稳定性的要求很高。本文通过现场测试与追踪调查,证明赛场噪声是影响平衡木运动员比赛时动作稳定性的重要因素;平衡木运动员必须有的放矢地加强抗噪声干扰的心理训练。     

Ageing and free-living daily physical activity effects on salivary beta-defensin 2 secretion

This study examined ageing and free-living daily physical activity effects on salivary human beta-defensin 2 (hBD2). A total of 168 healthy elderly and 26 healthy young volunteers underwent saliva sampling. Free-living step count, energy expenditure and activity durations at specific intensity levels (inactive, light, moderate and vigorous) were evaluated. The results show significantly lower salivary hBD2 secretion rates for elderly than for young participants (P < 0.05). Data from elderly participants were stratified by steps per day using quartiles (Q1–Q4) for distribution. Elderly in quartiles respectively showed step counts of 3145 ± 129 in Q1, 5294 ± 83 in Q2, 7001 ± 86 in Q3 and 10,236 ± 416 steps · day^?1 in Q4. In elderly participants, significant differences were found in the mean step count, energy expenditure and activity duration with increasing pedometer-determined activity quartiles. hBD2 secretion rates were significantly higher for Q2, Q3 and Q4 than for Q1 (P < 0.05). Elderly participants in Q3 had the highest hBD2 secretion. In conclusion, these results suggest that moderate physical activity in daily living improves age-related impairment of oral immune function mediated by hBD2. For oral immune function enhancement and for prevention of upper respiratory tract infections in elderly people, we recommend accumulation of more than 7000 steps · day^?1.     

混凝土梁桥常见病害分析及加固技术

由于运营条件的改变、设计及施工不当、灾害荷载和环境作用等原因,许多在役桥梁都出现了不同程度的病害,不少桥梁甚至失去正常的承载和通行能力,以至于不得不停止通行。论述混凝土梁桥经常出现的病害及其病害产生的原因,着重介绍各种病害常用加固方案和它的加固机理、适用范围、加固工艺,并结合工程加固实例,详述其加固计算方法与步骤。     

高性能聚焦离子束(FIB)系统及其在材料科学领域的应用

采用液态镓作为离子源的FIB系统在材料科学研究领域可以起非常重要的作用。离子束聚焦于样品表面，在不同大小、束流及通入不同辅助气体的情况下，可分别实现图形刻蚀、绝缘和金属膜的沉淀，扫描离子成像等功能。该系统有三大用途：形貌观察，分辨率高达5nm；微刻蚀以及微沉淀。本文介绍了FIB技术的应用。     

中国人口老龄化趋势下老年人科学健身发展策略

进入21世纪,中国人口老龄化趋势日渐明显,作为世界上唯一的老年人口过亿的国家,老年人的健康问题自然成为社会大众关注的热点。通过分析中国社会日渐凸显的老龄化特点,针对老年人的健康状况,研究制定适合老年人体育健身的方法,以促进老年体育朝着科学健康的方向发展。     

Degradation characteristic of 4-bromdiphenyl ether in mixed solutions by electron beam irradiation

The degradation characteristic of 4-bromdiphenyl ether （BDE-4） was investigated in different solutions.The study indicates that the process of direct degradation of this compound is dependent upon the bromine and the ether bond connected to diphenyl by electron beam.laser flash photolysis was employed to determine the degradation of each species （cationic,neutral,and anionic）.From these data,intermediate products of BDE-4 degradation were shown for direct irradiationdegradation.The neutral radical was formed during the photolysis of these compounds.For all the compounds,diphenyl ether and hydroxybiphenyl were observed as common products.Reaction of the BDE-4 under electron beam was debromide.The debromide rate of BDE-4 at pH=5.5 is somewhat lower than that of BDE-4 at pH=10.0.The decomposition rate for BDE-4 is 99.8% at pH=10.0 on the dose of 14 kGy.BDE-4 from its radical could provide bromine ion into water and the cation radical of BDE-4 formed quickly recombine with hydrogen radical and formed phenyl ether.     

高架桥连续梁盖梁混凝土冬季施工

介绍了高架现浇梁预应力混凝土冬季施工技术,对混凝土冬期施工质量因素进行了研究并采取了相应的措施,从而确保工程质量与安全。     

Effect of corrosion on bond behavior and bending strength of reinforced concrete beams

There is growing concern for corrosion damage in reinforced concrete structures with several decades’ service. Pullout tests and beam tests were carried out to study the effect of reinforcement corrosion on the bond behavior and bending strength of reinforced concrete beams. The bond strength of plain bars and concrete initially increases with increasing corrosion, then declines. The turning point depends on the cracking of the concrete cover. The bond strength of deformed bars and concrete increases with corrosion up to a certain amount, but with progressive increase in corrosion, the bond strength decreases, and the cracking of the concrete cover seems to have no effect on the bond strength. On the basis of test data, the bond strength coefficient recommended here, which, together with the bond strength of uncorroded steel bars and concrete, can be used to easily calculate the bond strength of corroded steel bars and concrete. The bond strength coefficient proposed in this paper can be used to study the bond stress-slip relationship of corroded steel bars and concrete. The bending strength of corroded reinforced concrete beams declines with increasing reinforcement corrosion. Decreased bending strength of corroded RC beam is due to reduction in steel bar cross section, reduction of yield strength of steel bar, and reduction of bond capacity between steel bar and concrete. Project supported by Cao Guanbiao Key Technology Development Founding of Zhejiang University and Construction Ministry of China.     

阶梯教室部分预应力框架梁工程的设计

通过本工程的预应力设计实例 ,简要介绍部分预应力框架梁的设计步骤和要点及对施工的要求