同步电机转子的检修探讨

同步电动机转子时常由于磁极松动,导致电机振动现象严重.本文以烧结厂1#抽烟机转子检修为例对同步电机的转子检修进行探讨,很好的解决了这个问题.同时为同步电机转子检修提供了一整套检修方法.     

考虑土-高层建筑群动力相互作用的振动台试验研究

为揭示高层建筑群间相邻结构动力相互作用机理和结构行为变化,设计2个土-结构体系对照模型,在场地土条件相同的情况下,一个仅有单独的上部结构、另一个则包含5个上部结构,并分别进行振动台试验,获取上部结构关键部位在地震动激励下的反应.试验结果显示:在地震作用下,高层建筑群内结构存在明显的相互作用,群体建筑的沉降和倾斜较单独建筑增大;相邻建筑的存在会使上部结构频率降低;相邻建筑的相互作用使上部结构加速度反应和位移反应有时增大,有时减小,此变化取决于输入地震波的频谱特性;建筑群内中部建筑的加速度和位移反应强于周围建筑.     

雾化铝粉筛分系统的改造

分析了原雾化铝粉筛分系统存在的问题，通过选择SV型三维振动筛，对原雾化铝粉筛分系统进行了技术改造。     

Proposition of a New Severity Analysis Based on ‘Shake’ Detection: Example of the Vatry Airport Tarmac

In packaging science, the study of transport is important in determining the viability of a package/product pair. Many load breaks occur (e.g. handling and storage) along a supply chain. Transport also generates various physical stresses (e.g. shocks, shakes and vibrations). These physical phenomena can be recorded using a variety of customized sensors (e.g. tri‐axial accelerometers, temperature sensors and pressure sensors). This study focuses on a transport phase that has not been studied in depth to date. Transportation operations on tarmacs include many handling and transportation machines, which are characterized by typical constraints that are often more stringent than airlift phase constraints. For comparison, acceleration distributions were estimated and analysed for the tarmac phase and road phase. Severity indicators were calculated based on existing methods. The second part of this study addresses the study of shakes. The shake distributions at 90 and 95% were another indicator of the shakes' severity and probability of occurrence. These elements allow us to characterize the impact of the tarmac area during air transport.     

传统民居穿斗式木构架抗震性能振动台试验研究

为研究西南地区木结构传统民居的抗震性能,对一个位于7度抗震设防烈度地区的两层、两跨穿斗式木构架进行模拟地震振动台试验。试验中选用3条天然波和1条人工波作为输入地震波,对模型结构的动力特性、加速度响应、位移响应、地震剪力及耗能能力进行分析。研究结果表明：随着输入加速度峰值的增加,模型结构自振频率减小,阻尼比增大。在加速度峰值为022g的地震作用后,模型结构X向和Y向的一阶自振频率分别降低了1069%和1997%,相应阻尼比分别增大到1606%和1747%。结构各层加速度放大系数随着加速度峰值的增加而降低,檐柱顶处的加速度放大系数在整个结构中最小,说明檐柱顶处榫卯节点在振动过程中减震作用明显。在加速度峰值为022g的地震作用下,结构最大层间位移角为1/53,此时未见模型有显著破坏,表明模型木构架具有良好的整体变形能力和抗倒塌能力。整个试验过程中,一层柱架耗能作用最大,柱脚耗能作用最小。     

Investigation on acceleration performance improvement of electro-hydraulic shake tables using parametric feedforward compensator and functional link adaptive controller

Electro-hydraulic shake table (EHST), also known as earthquake simulator, is of considerable significance in civil engineering for evaluating structures or infrastructures subjected to earthquake ground motions. However, reproduction of prescribed accelerations at table for EHST systems remains to be imperfect as the whole systems are confronted with hydraulic nonlinearity, varying dynamics, unexpected disturbance, etc. For enhancing the acceleration tracking performance of EHST systems, an acceleration waveform reproduction strategy using offline designed parametric feedforward compensator (PFC) and online functional link adaptive controller (FLAC) is proposed in this paper. The PFC controller is established on the basis of classical three variable controller (TVC) as an inner compensation loop, in which multi-innovation forgetting gradient (MIFG) algorithm together with zero magnitude error tracking (ZMET) technique are utilized during the design process. The FLAC controller is combined to the PFC controller as an outer loop for further acceleration enhancement purpose, and the controller’s nonlinear mapping ability is achieved with trigonometric expansion implementation. Following theoretical analysis of the proposed controller, comparative experiments are performed on an established unidirectional EHST test bench with both random and real-time recorded earthquake input waveforms. The experimental results validate the feasibility and superiority of the proposed acceleration reproduction strategy.     

重组猪源抗菌肽Cecropin P1在毕赤酵母中的分泌表达与活性研究

为构建活性表达重组猪源抗菌肽Cecropin P1的酵母基因工程菌,采用重叠区基因扩增拼接法设计并合成其编码基因,分别载入分泌型表达载体pPICZαB和pGAPZαA中,酶切线性化后电穿孔导入酵母细胞进行整合,经高拷贝整合子筛选以及表型筛选获得高效表达抗菌肽的重组菌株,经培养条件优化确定摇瓶发酵抗菌肽的最佳收获时间,据...     

兰尖铁矿采场爆破采取的降震措施

介绍了孔间、孔内和孔间微差爆破的原理、参数、设计施工要点及在降低爆破震动、保护平硐溜井使用安全方面的应用结果.     

Seismic testing and numerical analysis of Y‐shaped eccentrically braced frame made of high‐strength steel

In eccentrically braced frame made of high‐strength steel (HSS‐EBF), link and brace are made from conventional steel whereas other structural members use high‐strength steel. Using HSS for beams and columns in EBF can reduce steel consumption and increase economic efficiency. In this paper, one shake table test of a 1:2 scaled three‐story Y‐shaped HSS‐EBF (Y‐HSS‐EBF) specimen was carried out to study its seismic behavior underground motions with different peak ground accelerations. The dynamic properties, base shear force, displacement, and strain responses of the specimen were obtained from this test. In addition, the finite element models of two 10‐story Y‐HSS‐EBF buildings and one 10‐story conventional Y‐EBF building were evaluated for seismic effects. Nonlinear pushover and dynamic analyses were conducted to compare their seismic performance and economy. The results indicated that the specimen exhibited sufficient lateral stiffness and safety but suffered some localized damages. During the high seismic intensity earthquakes, the links of the test specimen were in inelastic to dissipate the earthquake energy, whereas other structural members remained in the elastic state. Under the same design conditions, Y‐HSS‐EBF used less steel than that of conventional Y‐EBF, which could reduce the amount of steel used in Y‐HSS‐EBF. The Y‐HSS‐EBF is a safe, dual system with reliable seismic performance.