鳊鱼洲长江大桥南汊航道桥钢锚箱施工关键技术

鳊鱼洲长江大桥南汊航道桥为主跨672 m双塔双索面钢箱混合梁斜拉桥,采用H形混凝土桥塔,索塔锚固区位于上塔柱区域。为优化索塔锚固区结构受力、简化施工,采用大节段式钢锚箱与十字形内腔混凝土组合新结构,十字内腔中间为钢锚箱,钢锚箱节段间分离并自由过渡,通过剪力钉与桥塔混凝土结合。钢锚箱为箱形全焊结构,长7.0 m,宽2.0 m,由侧面拉板、端板、锚室构成,材质为Q370qE钢。节段分离式钢锚箱分单元逐个制造锚室,再与钢锚箱壁板拼焊成钢锚箱节段,节段间采用“1+3”卧式短线法匹配试拼装,试拼装匹配完成后,节段间设置高程限位卡板和平面导向限位件,以实现钢锚箱现场吊装时的快速定位。实际施工中单节标准钢锚箱节段吊装及精调定位时间约4 h,安装精度满足规范要求。

Matched or nonmatched interventions based on the transtheoretical model to promote physical activity.A meta-analysis of randomized controlled trials

Purpose: The aim of this study was to examine whether the efficacy of transtheoretical model(TTM)-based interventions on physical activity(PA)varied according to the following criteria:(1) interventions targeted the actual stages of change(SOCs) or did not;(2) participants were selected according to their SOC or were not; and(3) its theoretical constructs(decisional balance, temptation, self-efficacy, processes of change).Methods: Thirty-three randomized controlled trials assessing TTM-based interventions promoting PA in adults were systematically identified.Results: The between-group heterogeneity statistic(Qb) did not reveal any differential efficacy either in interventions targeting the actual SOC compared with those that did not(Qb = 1.48, p = 0.22) or in interventions selecting participants according to their SOC compared with those that did not(Qb = 0.01, p = 0.91). TTM-based interventions enhanced PA behavior whether they targeted the actual SOC(Cohen's d = 0.36; 95%confidence interval(CI): 0.22–0.49) or not(d = 0.23; 95%CI: 0.09–0.38) and whether they selected their participants according to their SOC(d = 0.33; 95%CI: 0.13–0.53) or not(d = 0.32; 95%CI: 0.19–0.44). The moderators of the efficacy of TTM-based interventions were the number of theoretical constructs used to tailor the intervention(Qb = 8.82, p = 0.003), the use of self-efficacy(Qb = 6.09, p = 0.01), and the processes of change(Qb = 3.51, p = 0.06).Conclusion: TTM-based interventions significantly improved PA behavior, and their efficacy was not moderated by SOC but by the TTM theoretical constructs.

Experimental study on performance of contra-rotating axial flow fan

Contra-rotating axial flow fan is a kind of the vital equipment in coal mines. Their work conditions directly affect the safety of staff and production. In the paper, the performance of the contra-rotating axial flow fan is experi- mentally investigated. The study is focused on the fan performance, the shaft power and the match between the motor and fan efficiency at different blade angles. The results show that the blade angle 43°/26° has the best aerodynamic perfor- mance. The first engine has a greater impact on the fan than the second one. The blade angle with the best aerodynamic performance does not necessarily correspond to the one with the best match between the motor and fan efficiency. The blade angle 43°/24° is the best choice for the operation of the fan in the present study.

On the Causes of Negative Impact of CET-4

As one of the world well-known high-stakes tests, CET-4 （College English Test Band 4） changed from being generally accepted to being widely questioned in the past 25 years. In spite of a series of reforms of CET-4, the negative impact of CET-4 remains intense. Three main reasons are probed into here. Firstly, the objective of CET-4 is ambiguous. Secondly, the test objective does not accord with teaching objective. Finally, test contents do not match well with the practical language use. To improve the present passive state of CET-4, some suggestions are given.

A new diamond bit for extra-hard, compact and nonabrasive rock formation

A new impregnated diamond bit was designed to solve the slipping problem when impregnated diamond bit was used for extra-hard, compact, and nonabrasive rock formation. Adding Si C grits into matrix, Si C grits can easily be exfoliated from the surface of the matrix due to weak holding-force with matrix, which made the surface non-smooth. Three Ф36/24 mm laboratorial bits were manufactured to conduct a laboratory drilling test on zirconiacorundum refractory brick. The laboratory drilling test indicates that the abrasive resistance of the bit work layer is proportional to the Si C concentation. The higher the concentration, the weaker the abrasive resistance of matrix. The new impregnated diamond bit was applied to a mining area drilling construction in Jiangxi province, China. Field drilling application indicates that the ROP(rate of penetration) of the new bit is approximately two to three times that of the common bits. Compared with the common bits, the surface of the new bit has typical abrasive wear characteristics,and the metabolic rate of the diamond can be well matched to the wear rate of the matrix.

Automatic GUI Test by Using SIFT Matching

In software development process, the last step is usually the Graphic User In- terface（GUI） test, which is part of the final user experience （UE） test. Traditionally, there exist some GUI test tools in the market, such as Abbot Java GUI Test Framework and Pounder, in which testers pre-configure in the script all desired actions and instructions for the computer, nonetheless requiring too much of invariance of GUI environment; and they require reconfiguration in case of GUI changes, therefore still to be done mostly manually and hard for non-programmer testers to. Consequently, we proposed GUI tests by image recognition to automate the last process; we managed to innovate upon current algorithms such as SIFT and Random Fern, from which we develop the new algorithm scheme retrieving most efficient feature and dispelling inefficient part of each algorithm. Computers then apply the algorithm, to search for target patterns themselves and take subsequent actions such as manual mouse, keyboard and screen I/O automatically to test the GUI without any manual instructions. Test results showed that the proposed approach can accelerate GU! test largely compared to current benchmarks.

Beam Line Design and Construction of Gas Target for a 30MeV Medical Cyclotron

The first medical high intensity cyclotron CYCIAE-30 and its beam line for the isotope production were built in 1994 at China Institute of Atomic Energy.Now,an upgrading beam line system is designed based on the existing beam line of CYCIAE-30 to transport the beam extracted from the cyclotron to a gas target for the new isotope production,including elements location design,optics simulation and magnet design.The machining and installation of all the elements are accomplished based on the design.The beam tuning is finished and the transmission of 96.5% is obtained.

小议池钓空竿原因

池钓空竿对于初学者来说是常见的事,即便是老手,有时也难逃厄运。究其原因,大致有以下几种。 1.钓具组合不匹配。钩、坠、漂组合不匹配,最易发生空竿。许多垂钓爱好者,特别是初学者,一到养鱼池就按捺不住急切的心情,钩、坠、漂稍加调试或不加调试就匆匆下竿。抑或在家进行过调试,但到鱼池后未加校验就垂钓;在一鱼池垂钓后,换一鱼池懒于重新校验调试就垂钓,都容易发生空竿。笔者有几次空竿的教训:一次和钓友到养鱼池垂钓鲫鱼和鲤鱼(前半时钓鲫鱼,后半时钓鲤鱼)。