一种基于NFC的无源智能锁及其在配电网中的应用

针对配网柜体采用的传统机械锁具管理难度大、破解容易以及可追踪性差,无法满足现代电网快速发展的多样化需求等问题。该文研制了一种基于配电物联网架构的无源高可靠性智能电子锁。其内嵌安全芯片,采用近场通信(Near Field Communication,NFC)技术完成通信及取能,无需机械钥匙开锁,无需维护更换锁具电池,并配套开发了能够实时监测锁具状态、储存开锁信息的智能锁管理系统以及配合开锁APP使用的电子钥匙,分析了智能锁具的硬件设计及系统的应用流程。最后,通过实践应用表明,该套锁具系统在运维便捷、信息安全和科学管理方面具有明显效用。     

Colostrum source and passive immunity transfer in dairy bull calves

Colostrum is essential for good neonate health; however, it is not known whether different calves absorb the nutrients from colostrum equally well. In this study, the absorption of protein, IgG, and γ-glutamyl transferase was compared in newborn dairy bull calves for 1 wk after feeding colostrum from different sources. Thirty-five Holstein-Friesian bull calves were randomly allocated into 3 groups and fed colostrum within 4 h after birth. Group A calves (n = 12) were bottle fed colostrum from their own dam for 3 d. Colostrum from these group A cows was also used as foster cow colostrum for the group B calves (n = 12), such that each group A and B calf pair received identical colostrum from each milking of the respective group A dam (10% of birth weight per day). The group C calves (n = 11) were fed 1 bottle (2 L) of pooled colostrum and transition milk (referred to as pooled colostrum), as was the standard practice on the dairy farm. The pooled colostrum was collected from the other dairy cows on the farm 0 to 4 d postpartum and stored at 4°C for less than 12 h. Blood was sampled from calves before the first feeding and at 1, 2, 3, and 7 d after birth. Levels of total solids, total protein, and IgG were higher in the dam colostrum than in the pooled colostrum. At birth, there were no differences between the calf groups for any measurements, and all calves had very low IgG levels. After receiving colostrum, the glucose, plasma γ-glutamyl transferase, serum total protein, and IgG concentrations increased significantly in all calves. There were no differences in any blood measurements at any time point between the pairs of group A and group B calves that received colostrum from the same cow except for the IgG concentration 2 d after birth. However, the group A calves had a higher total serum protein level and IgG concentration than the group C calves for all the time points after the first feeding. The group B calves had a higher IgG concentration than the group C calves on d 1, 2, and 7 after birth. Compared with groups A and B, there was no difference in the proportion of calves in group C that failed to have passive immunity transferred adequately based on the IgG threshold (<10 g/L). Thus, the calves receiving identical colostrum from the same cow had the same levels of IgG, and even the pooled colostrum provided sufficient transfer of IgG as the calves were fed within 4 h after birth.     

PLC与SEW多轴伺服驱动总线集成在玻璃生产线控中的应用

本文介绍了一种将西门子PLC与SEW多轴伺服驱动通过PROFINET总线组合集成的一套玻璃生产线线控系统的应用方案。     

乌弄龙水电站运行期岩壁吊车梁稳定性预测分析

为预测乌弄龙水电站运行期岩壁吊车梁的稳定性,依据乌弄龙水电站地下厂房岩壁吊车梁原型监测数据,分析岩壁吊车梁在洞室群开挖卸荷过程的围岩应力、变形及锚杆应力特征;运用三维整体数值模拟进行反演及动态反馈分析,仿真计算岩壁吊车梁运行期变形及应力特点;通过原型监测和仿真模拟,评估岩壁吊车梁的安全稳定性。预测结果表明,岩壁吊车梁能安全运行,与实际运行情况一致。研究成果可为同类工程提供参考。     

磨削压力及速度对钢轨被动打磨性能的影响

以钢轨圆盘代替钢轨，设计一种模拟钢轨被动打磨方式的实验平台，研究被动磨削方式下磨削压力和磨削速度对磨削力、磨削温度、磨削效率及钢轨表面粗糙度的影响。实验结果表明: 在60～80 km/h范围内，随磨削速度增大，切向磨削力、表面粗糙度减小，磨削温度升高、磨削效率增大；在120～320 N范围内，随磨削压力增大，磨削温度升高、切向磨削力增大、磨削效率增大、表面质量下降。      

Scalable Clock Synchronization Analysis: A Symmetric Noncooperative Output Feedback Tubes-MPC Approach

In the cyber-physical environment, the clock synchronization algorithm is required to have better expansion for network scale. In this paper, a new measurement model of observability under the equivalent transformation of minimum mean square error (MMSE) is constructed based on basic measurement unit (BMU), which can realize the scaled expansion of MMSE measurement. Based on the state updating equation of absolute clock and the decoupled measurement model of MMSE-like equivalence, which is proposed to calculate the positive definite invariant set by using the theoretical-practical Luenberger observer as the synthetical observer, the local noncooperative optimal control problem is built, and the clock synchronization system driven by the ideal state of local clock can reach the exponential convergence for synchronization performance. Different from the problem of general linear system regulators, the state estimation error and state control error are analyzed in the established affine system based on the set-theory-in-control to achieve the quantification of state deviation caused by noise interference. Based on the BMU for isomorphic state map, the synchronization performance of clock states between multiple sets of representative nodes is evaluated, and the scale of evaluated system can be still expanded. After the synchronization is completed, the state of perturbation system remains in the maximum range of measurement accuracy, and the state of nominal system can be stabilized at the ideal state for local clock and realizes the exponential convergence of the clock synchronization system.      

Pitting growth rate on Alloy 800 in chloride solutions containing thiosulphate: image analysis assessment

The growth rate of pits formed on Alloy 800 in chloride solutions containing various thiosulphate concentrations was assessed by potentiostatic polarisation, in situ corrosion image observation, and image analysis. The pitting growth rate was a function of solution chemistry: in chloride solution pits were small but numerous, in chloride?+?thiosulphate solution, the pits were large. Competitive adsorption on Alloy 800 of chloride and thiosulphate ions affected the pitting potential and therefore the pitting growth rate on the metal. The reduction of thiosulphate to elemental sulphur accelerated the pitting growth rate in chloride?+?thiosulphate solutions.     

Electrochemical corrosion behavior of LDX 2101® duplex stainless steel in a fluoride-containing environment

The effect of fluoride on the electrochemical corrosion behavior of an LDX 2101® duplex stainless steel (DSS) was studied. Open-circuit potential (E_OC) and electrochemical impedance spectroscopy (EIS) measurements were carried out in artificial saliva and with the addition of fluoride (1 wt% NaF). The electrochemical corrosion behavior of the AISI 316L austenitic stainless steel (SS) was also evaluated for comparison. Both open-circuit potential and EIS results indicate that DSS and austenitic SS undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface, in the simulated aggressive environments. However, LDX 2101® exhibits superior corrosion resistance as compared with AISI 316L, and this improvement is ascribed to the formation of a passive film which shows a higher protective effect than the one formed on AISI 316L.