西门子PLC与WinCC在散粮筒仓监控系统中的应用

设计了一种基于西门子可编程逻辑控制器(PLC)与WinCC相结合的分布式散粮筒仓监控系统。系统以西门子S7-300系列PLC与ET200M组成下位机,以安装有WinCC控制程序的工控机作为上位机,通过结构化编程对监控系统进行设备启停和进出仓线路设计,建立了相应的人机界面,实现对整个控制系统的集中管理和实时监控。

A Special Additive Enables All Cations and Anions Passivation for Stable Perovskite Solar Cells with Efficiency over 23%

Passivating undercoordinated ions is an effective way to reduce the defect densities at the surface and grain boundaries(GBs)of perovskite materials for enhanced photovoltaic performance and stability of perovskite solar cells(PSCs).Here,(BBF)complex is chosen as a multifunctional additive,which contains both C7H9N and BF3 groups working as Lewis base and Lewis acid,respectively,can bond with Pb^(2+)/I^(−) and FA+on the surface and in the GBs in the perovskite film,affording passivation of both cation and anion defects.The synergistic effect of the C7H9N and BF3 complex slows the crystallization during the perovskite film deposition to improve the crystalline quality,which reduces the trap density and the recombination in the perovskite film to suppress nonradiative recombination loss and minimizes moisture permeation to improve the stability of the perovskite material.Meanwhile,such an additive improves the energy-level alignment between the valence band of the perovskite and the highest occupied molecular orbital of the hole-transporting material,Spiro-OMeTAD.Consequently,our work achieves power conversion efficiency of 23.24%,accompanied by enhanced stability under ambient conditions and light illumination and opens a new avenue for improving the performance of PSCs through the use of a multifunctional complex.

Multi-type sensor placement and response reconstruction for building structures: Experimental investigations

Estimation of lateral displacement and acceleration responses is essential to assess safety and serviceability of high-rise buildings under dynamic loadings including earthquake excitations. However, the measurement information from the limited number of sensors installed in a building structure is often insufficient for the complete structural performance assessment. An integrated multi-type sensor placement and response reconstruction method has thus been proposed by the authors to tackle this problem. To validate the feasibility and effectiveness of the proposed method, an experimental investigation using a cantilever beam with multi-type sensors is performed and reported in this paper. The experimental setup is first introduced. The finite element modelling and model updating of the cantilever beam are then performed. The optimal sensor placement for the best response reconstruction is determined by the proposed method based on the updated FE model of the beam. After the sensors are installed on the physical cantilever beam, a number of experiments are carried out. The responses at key locations are reconstructed and compared with the measured ones. The reconstructed responses achieve a good match with the measured ones, manifesting the feasibility and effectiveness of the proposed method. Besides, the proposed method is also examined for the cases of different excitations and unknown excitation, and the results prove the proposed method to be robust and effective. The superiority of the optimized sensor placement scheme is finally demonstrated through comparison with two other different sensor placement schemes： the accelerometer-only scheme and non-optimal sensor placement scheme. The proposed method can be applied to high-rise buildings for seismic performance assessment.

Graded 2D/3D(CF_(3)-PEA)_(2)FA_(0.85)MA_(0.15)Pb_(2)I_(7)/FA_(0.85)MA_(0.15)PbI_(3) heterojunction for stable perovskite solar cell with an efficiency over 23.0%

The replacement of small cations with bulkier organic cations containing long alkyl chains or benzene rings to form a thin two-dimensional(2D)perovskite passivation layer on three-dimensional(3D)perovskite(2D/3D)has become a promising strategy for improving both the efficiency and stability of perovskite solar cells(PSCs).The 2 D layer defines the interfacial chemistry and physics at the 2D/3D bilayer and endows the 2D/3D structure with better chemical and thermal stability.Herein,2D/3D(CF_(3)-PEA)_(2) FA_(0.85)MA_(0.15)Pb_(2)I_(7)/FA_(0.85)MA_(0.15)PbI_(3) planar heterojunction perovskite was produced using a facile interfacial ion exchange process.The 2 D(CF_(3)-PEA)_(2) FA_(0.85)MA_(0.15)Pb_(2)I_(7) capping layer can not only passivate the FA_(0.85)MA_(0.15)PbI_(3) film but also act as super-hydrophobic layer to inhibit water diffusion and significantly enhance the stability.The 2D capping layer can also establish a unique graded band structure at the perovskite/Spiro-OMeTAD interface and lead to p-type doping for Spiro-OMeTAD layer which is beneficial for efficient charge transport.Optimized PSCs based on this 2D/3D heterojunction yield a champion power conversion efficiency(PCE)of 23.1%and improved stability.The device maintains 84%output for 2400 h aging under ambient environmental conditions without encapsulation,and maintains 81%for 200 h under illumination with encapsulation.This work will inspire the design of more fluorinated 2D perovskite interfaces for advanced photovoltaics and beyond.

Countermeasures for Remediation of Soil Pollution in Metal Mines

Firstly,the causes and existence state of soil pollution in metal mines were discussed.Secondly,the remediation technology of heavy metal contaminated soil was introduced.Thirdly,the remediation strategies for soil pollution in metal mines were analyzed.Finally,the problems and development direction of soil pollution remediation and control in metal mines were discussed.

Multi-type sensor placement and response reconstruction for structural health monitoring of long-span suspension bridges

This study is devoted to the experimental validation of the multi-type sensor placement and response reconstruction method for structural health monitoring of long-span suspension bridges. The method for multi-type sensor placement and response reconstruction is briefly described. A test bed, comprising of a physical model and an updated finite element(FE) model of a long-span suspension bridge is also concisely introduced. The proposed method is then applied to the test bed; the equation of motion of the test bed subject to ground motion, the objective function for sensor location optimization, the principles for mode selection and multi-type response reconstruction are established. A numerical study using the updated FE model is performed to select the sensor types,numbers, and locations. Subsequently, with the identified sensor locations and some practical considerations, fiber Bragg grating(FBG) sensors, laser displacement transducers, and accelerometers are installed on the physical bridge model. Finally, experimental investigations are conducted to validate the proposed method. The experimental results show that the reconstructed responses using the measured responses from the limited number of multitype sensors agree well with the actual bridge responses.The proposed method is validated to be feasible and effective for the monitoring of structural behavior of longspan suspension bridges.

Double-Shelled L1_(2) Nano-structures in Quaternary Al–Er–Sc–Zr Alloys: Origin and Critical Significance

The formation of highly coherent double-shelled L1_(2) nano-precipitates in dilute Al–Er–Sc–Zr alloys was investigated with the combined use of Cs-corrected transmission electron microscopy characterization and first-principles energetics calculations. The double-shelled nano-precipitates are primarily featured with an Er-rich core surrounded by a Sc-rich inner shell and a Zr-rich outer shell. First-principles energetics analyses based on the classic homogenous nucleation theory suggested that once forms, this double-shell structure can be thermally stable. The predominant formation of this double-shell structure has thus both profound kinetic and thermodynamic origins. Its formation and stability preference to all other possible L1_(2) nano-structures would become more pronounced as its size increases, no matter what the solute ratio and aging temperature of interest.