数据中心典型开关电源柜抗震性能拟静力试验研究

开关电源柜是数据中心(IDC)的重要设备,其在地震作用下的功能和性能表现对数据中心震后功能正常工作有重要影响。本文对一种典型开关电源柜进行了拟静力试验,研究其在水平地震荷载作用下的损伤特征,获得相关力学性能参数,为准确建立开关电源柜有限元分析模型提供依据。试验所用的开关电源柜包括交流柜、整流柜和直流柜三个柜体,试验中对三个柜体分别沿其抗震弱方向进行低周往复加载,逐级增大柜顶位移直至柜体发生严重破坏或丧失使用功能,观察柜体损伤发展过程及特征损伤现象,研究破坏机理,获得承载力-变形滞回曲线。由试验结果分析可知：在加载初期,柜门在柜体内起到了“斜撑”作用,是柜体抗侧力的主要贡献;当柜门的“斜撑”作用失效后,柜体钢框梁柱节点焊缝开裂并逐步延展和柱脚压曲,继而抗侧力框架发生严重破坏,承载力丧失。     

Effectiveness of monsoon floods on the Tapi River, India: role of channel geometry and hydrologic regime

Geomorphic effects of floods are a function of several controlling factors, such as magnitude, frequency, rate of sediment movement, flood power, duration of effective flows, sequence of events and the channel geometry. In this paper, these measures of effectiveness have been evaluated for the monsoon-dominated, flood-controlled and incised Tapi River, India by defining four flow categories: low flows, moderate flows, floods and large floods. Ratios between effectiveness parameters of moderate flows on one hand and the floods, large floods and maximum floods on the other, were computed to understand the relative importance of moderate and large flows. In addition to this, stream-power graphs for large floods were constructed, and the changes in channel form were analyzed by using multi-date cross-sections. The results of the study indicate that the morphological characteristics of the bedrock as well as the alluvial channels of the monsoonal and incised Tapi River are maintained by large-magnitude, but low frequency floods that occur at long intervals. Because the channel is incised the effectiveness of large flows is accentuated. The incised channel form enhances the role of large floods by reducing the width–depth ratio, and by increasing the velocity as well as the energy per unit area. The low and moderate flows are superior to high-magnitude flows, only in terms of suspended sediment transport and frequency of occurrence. Another conclusion is that the suspended sediment carried by flows may not be the most appropriate criterion for measuring the geomorphic effectiveness of flows, particularly for monsoonal rivers.     

局域地应力场获取的插值平衡方法

针对由整体地应场插值计算局域地应力场的问题计算量大、受地质结构的影响大、不过分追求高精度等特点,改进了反距离加权插值法,考虑了单元体积的影响,提高了该方法在此问题中的适用性。基于此,提出了平面问题、三维地面和地下工程局域地应力场的求取策略,建议了边界全平动约束和法向约束两种边界条件,并验证了其合理性和适用场合。最后,在大型水电工程深切河谷坝肩边坡分析中进行了应用分析。结果表明：该插值方法简单实用,能够满足工程分析的精度要求;局域地应力场的求取策略计算效率高,计算精度能够满足工程分析的要求。     

磁性层顶底埋深的功率谱计算方法及影响因素

功率谱法是计算磁性层顶、底界面埋深的常用方法之一,但是它在实际应用过程中受到一些因素的影响,可能会使解释结果产生偏差.利用磁异常功率谱对二度磁性体的顶、底界面埋深进行计算,通过对其高阶导数的功率谱计算埋深的近似公式的分析,探讨了影响功率谱计算埋深的因素,提高了该方法的可靠性.     

地震势能剖面

地质体在应力场的作用下发生弹性形变,从而具有应变位能（势能）。应用应变位能公式,可以将位或位移转化为势能,用势能剖面代替常规地震剖面。由于势能转换能拓宽地震信号的有效频谱,具有高通滤波性质,同时又不损害低频信号,所以,同常规地震剖面相比,势能剖面在保持信噪比的前提下,有更高的纵、横向分辨率。通过势能转换的理论分析及合成数据和实际数据的势能转换处理,本文系统地研究了势能转化问题和实现方法,从而证明势能转换确实是行之有效的高分辨率地震处理方法,可用于实际地震资料的处理。     

高效多路直流开关电源

本文介绍一种新型的直流开关电源,该电源是一种直流电压输入,三种直流电压输出,并能够达到相当高的效率。这种电源适用于数字化设备的无人职守台站。本文也论述了实现的技术思路和达到的技术要求。     

Impact of tidal power dams upon tides and environmental conditions in the Sea of Okhotsk

The transformation of natural tidal sea-level and currents is studied resulting from large-scale tidal power plant (TPP) dams in bays of the Sea of Okhotsk (SO). Some effects due to this transformation are estimated based on predictive modelling and a number of expected changes in amplitudes and phases, and spectral composition of tidal oscillations are described. Changes of morphometric properties of basins change the character of tidal motions even on significant distance from a dam. That is why, it is impossible to estimate this impact as usual boundary-value problems. The problem is solved based on “impedance” conditions on the open boundary of the model area, allowing to take into account the radiation of the additional perturbations induced by both waves reflected from the dam and nonlinear effects inside the area. In general, the transformation effects are proportional to the dam size and depend essentially on the dam location, the creation of which can change dissipative and resonance properties of the bays. The changes in tidal energetics of SO due to the dam construction are also considered to show noticeable reconstruction of horizontal energy fluxes and changes in the energy dissipation. Possible environmental consequences are related mainly to the transformation of tidal currents.     

鹤岗地震台阵勘选数据分析

作为"一带一路"地震台网项目的子项目,鹤岗地震台阵区域位置特殊,在地震监测中担负着重要使命。2019年,黑龙江省地震局采用Reftek-130B地震数据采集器和CMG-3T宽频带地震计,完成台阵前期勘选工作,连续波形记录时间30天以上,波形记录质量良好。利用该台阵已勘选的15个点位连续波形记录,估计各点位功率谱,通过绘制概率密度函数图和单频曲线,初步分析该地区背景噪声变化特征。分析结果表明,各勘选点位的噪声功率谱密度相对稳定,部分点位受人类活动影响,在10 Hz以上存在突变,3-5、3-6、4-4子台高频变化较为明显,勘选点位的背景噪声变化特征可为今后的地震台阵建设提供依据。     

强震作用下核电厂顺层软岩高边坡组合支挡结构抗震性能研究

在综述国内核电厂高边坡案例研究进展的基础上,以某核电厂含泥化夹层顺层软岩高边坡为例,探讨应用多种方法综合分析其在地震作用下的动态放大效应、抗震性能和加固效果的分析思路。首先,基于典型二维计算剖面,采用拟静力法对边坡进行初步加固设计;然后,基于振动台试验和数值计算,研究边坡动态放大效应、支挡结构的动力响应和抗震性能,探讨边坡抗震参数优化取值。研究结果表明:(1)原位边坡坡面的加速度放大系数随高度增加而增大,且泥化夹层饱水后的放大系数要大于饱水前,水平向最大值为1.90;(2)加固后边坡动态放大系数显著降低,水平最大放大系数为1.31,垂直向基本为1.0,锚索抗滑桩以下边坡基本不存在放大效应,说明软岩高边坡采用锚索抗滑桩和锚索框架抗震性能较好;(3)PGA=0.21g时,边坡整体抗震性能较好,仅最顶部锚杆和中部锚索受力超过设计锚固力,分别超过设计值的20%和5%,适当加强即可;(4)数值计算得到的加速度放大系数分布规律与振动台试验结果较为一致,且两者得到的坡顶加速度放大系数也十分接近。研究成果可为核电厂软岩高陡边坡抗震安全评价和工程设计提供技术支持。