Improvement of Vertical Diffusion Analytic Schemes Under Stable Atmospheric Conditions

Based on gradient transport theory or K-theory, turbulent transport in the atmosphere has long been parameterized using the eddy diffusivity. Due to its simplicity, this approach has often been applied in many numerical models but rarely tested with observations. Here, the widely used O’Brien cubic polynomial approach has been validated together with an exponential approach against eddy diffusivity profiles determined from measurements and from large-eddy simulation data in stable conditions. Verification is completed by analyzing the variability effects on pollutant concentrations of two different vertical diffusion (K(z)) schemes incorporated in an atmospheric chemical model. It is shown that the analytical, exponential solution agrees better with observations than the O’Brien profile and should be used henceforth in practical applications.     

上海短历时强降水的雷达和闪电活动特征

用雷达反射率及其导出产品(分层垂直液态水含量(VIL)、分层平均反射率等)与闪电和大气温度层结资料,通过对降水系统时间演变、反射率垂直结构和闪电活动的分析,将上海2010年6—11月的短时强降水(1 h雨量≥20 mm)分为层状暖云型、对流暖云主导型和对流冷云主导型。(1) 与雨强密切相关的关键因子是:低层(0 ℃层以下、高度在0～1 km、0～2 km、0～3 km和0～4 km)的VIL、低层(高度在1～2 km、2～3 km和3～4 km)的平均反射率和整层最大反射率;(2) 不同类型强降水中,高层(高度在0 ℃、-10 ℃和-20 ℃层以上)的VIL、整层VIL、高层(高度在5～6 km、6～7 km和7～8 km)的平均反射率、总地闪和负地闪频次这5个因子对雨强的作用各有不同;(3) 对应不同降水类型的平均反射率垂直廓线具有不同的垂直结构和发展演变特征;(4) 在三类强降水中,对流冷云主导型的雨强与总地闪和正地闪的相关性最好。      

基于医疗联盟链的数据安全保护方法

随着互联网的飞速发展,医疗数据爆炸性增长,大量的医疗数据面临着安全共享问题.本文提出了一种基于医疗联盟链的数据安全保护方法,其中包括提出了一种安全认证与访问控制模型,并将查询逻辑分离存储技术引入该模型中,同时描述了基于医疗联盟链的认证凭据和访问权限数据的存储和访问.基于医疗联盟链的安全认证与访问控制模型包含了三个角色,第一角色是患者,第二角色是医护人员,第三角色是医疗联盟链.通过查询逻辑分离存储技术保护患者数据隐私,查询逻辑分离技术与医疗联盟链技术紧密结合,满足了不同医院之间医疗数据共享的需求,保障了患者的数据隐私和医护人员查阅数据的权限.     

A Spatial Consistency Quality Control Method for Daily Surface Temperature Observations

A new spatial consistency quality control method (SRF) based on the spatial regression test (SRT) and random forest (RF) was adapted to identify potential outliers in daily surface temperature observations in this article. For the new method, the SRT method was used to filter the data and the RF method was used to conduct regression. To evaluate the performance of the quality control method, the SRF, SRT and RF methods were applied to a surface temperature dataset with seeded errors from different regions of China from 2005 to 2014. Compared to SRT and RF, the results indicate that the SRF method outperforms the other two methods for the most cases. And the results of the comparison led to the recommendation that the SRF method improves the regression accuracy of traditional spatial consistency quality control methods and reduces the runtime of random forest through data refinement.     

Predictive instantaneous optimal control of inelastic structures during earthquakes

A new inelastic structural control algorithm is proposed by incorporating the force analogy method (FAM) with the predictive instantaneous optimal control (PIOC) algorithm. While PIOC is very effective in compensating for the time delay for elastic structures, the FAM is highly efficient in performing the inelastic analysis. Unlike conventional inelastic analysis methods of changing stiffness, the FAM analyzes structures by varying the structural displacement field, and therefore the state transition matrix needs to be computed only once. This greatly simplifies the computation and makes inelastic analysis readily applicable to the PIOC algorithm. The proposed algorithm compensates for the time delay that happens in practical control systems by predicting the inelastic structural response over a period that equals the magnitude of the time delay. A one‐story frame with both strain‐hardening and strain‐softening inelastic characteristics is analyzed using this algorithm. Results show that the proposed control algorithm is feasibile for any inelastic structures. While the control efficiency deteriorates with the increase in magnitude of the time delay, the PIOC maintains acceptable performance within a wide range of time delay magnitudes. Finally, a computer model of a six‐story moment‐resisting steel frame is analyzed to show that PIOC has good control results for real inelastic structures. Copyright © 2003 John Wiley & Sons, Ltd.     

东北地区近震震级研究

实际观测表明,用现行短周期仪器起算函数Ｒ１测算的近震震级ＭＬ在近距离地段数值偏低,在远距离地段偏高,随震中距出现系统偏差。本文以里克特（１９３５）零震级地震定义为震级水平控制原则,应用了辽,吉,黑,冀四省地震台网的观测资料,制定出东北地区近震震级起算函数系统。     

Implications of the saltation–abrasion bedrock incision model for steady‐state river longitudinal profile relief and concavity

The saltation–abrasion model predicts rates of river incision into bedrock as an explicit function of sediment supply, grain size, boundary shear stress and rock strength. Here we use this experimentally calibrated model to explore the controls on river longitudinal profile concavity and relief for the simple but illustrative case of steady‐state topography. Over a wide range of rock uplift rates we find a characteristic downstream trend, in which upstream reaches are close to the threshold of sediment motion with large extents of bedrock exposure in the channel bed, while downstream reaches have higher excess shear stresses and lesser extents of bedrock exposure. Profile concavity is most sensitive to spatial gradients in runoff and the rate of downstream sediment fining. Concavity is also sensitive to the supply rate of coarse sediment, which varies with rock uplift rate and with the fraction of the total sediment load in the bedload size class. Variations in rock strength have little influence on profile concavity. Profile relief is most sensitive to grain size and amount of runoff. Rock uplift rate and rock strength influence relief most strongly for high rates of rock uplift. Analysis of potential covariation of grain size with rock uplift rate and rock strength suggests that the influence of these variables on profile form could occur in large part through their influence on grain size. Similarly, covariation between grain size and the fraction of sediment load in the bedload size class provides another indirect avenue for rock uplift and strength to influence profile form. Copyright © 2008 John Wiley & Sons, Ltd.     

土木工程结构的双层多重调谐质量阻尼器控制策略

为能得到用尽可能少的调谐质量阻尼器(TMD)组成有效性和鲁棒性高的多重调谐质量阻尼器控制系统，本文提出了一种适用于土木工程结构的新控制策略——双层多重调谐质量阻尼器(DMT—MD)。使用定义的优化目标函数，评价了双层多重调谐质量阻尼器(DMTMD)的控制性能。数值结果表明，双层多重调谐质量阻尼器(DMTMD)比多重凋谐质量阻尼器(MTMD)具有更好的有效性和对频率调谐的鲁棒性。DMTMD比双重调谐质量阻尼器(DTMD)具有更好的有效性，而DMTMD和DT—MD对频率调谐的鲁棒性近似相同。因此，双层多重调谐质量阻尼器是一种先进的结构控制策略。     

浅层直流电法探测隐伏断层可行性分析

通过讨论断层不同表现形式的电性特征,对高密度电法与联合剖面法在隐伏断层探测中的应用可行性进行研究,并通过实例探讨了测试中应注意的问题、测试与解译方法。研究表明高密度电法及联合剖面法可以应用在隐伏断层探测中,但有一定的限制,主要源于断层的地质表现形式。     

Seismic structural control using an electric servomotor active mass driver system

This study investigates an electric‐type active mass driver (AMD) system for structural vibration control. Composed primarily of an electric servomotor and a ball screw, the electrical AMD system is free from noise problems, oil leakage, and labor‐intensive maintenance that commonly are associated with hydraulic AMD systems. The desired stroke amplification of the mass and the power demand of the servomotor can be adjusted via the ball screw pitch, which in turn affects the effectiveness and efficiency of the system. Meanwhile, an instantaneous optimal direct output feedback control algorithm is adopted. Numerical simulation is performed using a five‐story steel frame as the object structure under the conditions of the 1940 El Centro earthquake. The AMD system proves to be effective and efficient within a certain range of the ball screw pitch. The reductions of the peak responses can reach as high as 70% if properly designed. Requiring only the velocity measurement of the top floor for on‐line feedback control, the proposed control algorithm is recommended for practical implementation. Copyright © 2004 John Wiley & Sons, Ltd.