深孔表面三维形貌测量与控制装置的研制

针对深孔表面三维形貌难于检测的问题，在传统的触针扫描技术的基础上，利用柱面激光-全息光栅传感器，设计出了独特的光栅信号采集处理电路，采用大小数细分与融合的方法，来进行表面微观轮廓信息的采集。由上位机通过PCI总线的多功能板卡及步进电机细分驱动器来进行触针轴向微位移量的高精度运行控制，较好地实现了对深孔表面三维形貌的测量。详细介绍了深孔内表面三维形貌的测量与控制装置的测量原理、软硬件设计及特点，并给出了实验结果。     

Sliding wear behavior of copper alloy contact wire against copper-based strip for high-speed electrified railways

This paper reports the study of the sliding wear behavior of the Cu–Ag–Cr wire. Cu–Ag–Cr alloy is a promising contact wire material for high-speed electrified railways, which has an excellent combination of mechanical strength and electrical conductivity. Wear tests were conducted under laboratory with a special sliding wear apparatus, which simulated the tribological conditions of sliding current collectors on overhead wires in the railway system. The Cu–Ag–Cr alloy wire was slid against a copper-based powder metallurgy strip under unlubricated conditions. The same strip as those in the train systems were used. Worn surfaces of the Cu–Ag–Cr alloy wire were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrum (EDS). Within the studied range of electrical current, normal pressure and sliding speed, the wear rate increased with the increasing electrical current and the sliding distance. Compared with a Cu–Ag contact wire under the same conditions, the Cu–Ag–Cr alloy wire had much better wear resistance. Adhesive wear, abrasive wear and arc erosion were the dominant mechanisms during the electrical sliding processes.     

First principles calculations of the stability of the T2 and D88 phases in the V–Si–B system

The crystal and electronic structures of D8_l-V₅SiB₂ and D8₈-V₅Si₃B ternary compounds have been investigated by means of first principle calculations. The calculated structural parameters are in very good agreement with the experimental data. The calculated values of the enthalpies of formation at T = 0 K of the D8_l-V₅SiB₂ and D8₈-V₅Si₃B ternary compounds are −67.1 and −62.1 kJ/mol of atoms respectively. The total and partial electronic densities of states show a strong hybridization between the B p states and V d states. The defect enthalpies of formation as well as the mixing enthalpies have been computed. These data are essential for the modeling of the D8_l and D8₈ phases in the V–Si–B ternary system. A partial V–VSi₂–VB isothermal section at 298 K is proposed.     

ACS800传动单元制动电阻的计算与选择

本文用实例介绍了ACS800传动单元制动电阻的计算方法。     

Application of fluidization technology in productions of cemented carbides

The fluidization technique has advantages in rapid and high-efficiency heat transfer. Application of fluidization technology can significantly improve the productivity and product performance in the cemented carbide industries. This technique has become an attractive research topic within the issue of green and low-carbon technologies. Aiming at better understanding the principles of fluidization, in the present paper we demonstrate three typical cases of liquid–solid fluidized crystallization, bubbling bed combustion synthesis and reduction carbonization production. From these samples, we study the factors which play an important role in the fluid dynamics, fluidized state of materials and reaction thermodynamics during the process of cemented carbide production. The solutions and mechanisms of the practical problems such as the fluidized state of ultrafine particles, critical opening percentage of the distribution plate and adherent effect in multilayer bubbling bed are proposed. Moreover, the potential applications and prospects of the fluidization technology in the field of cemented carbides are presented.     

Alternatives to prevent the failure of RC members under close-in blast loadings

In this paper, an experimental study of the dynamic response of reinforced concrete (RC) members protected in different ways is presented. Two alternatives for the protection of RC members are designed and studied; classical steel jacketing and a new reinforced polyurethane sacrificial layer. The mitigation of shock and absorption of energy from the blast is studied with experimental methods. For comparison purposes, a RC member without protection is also tested and studied. As expected, the steel jacketing provided excellent protection reducing the maximum final deflection as well as reducing damage to the member. On the other hand, the proposed reinforced polyurethane protection performed reasonably well. The obtained results are useful for exploring new alternatives for the protection of RC columns as well as for the calibration of numerical codes.     

Lattice Boltzmann models for two-dimensional coupled Burgers’ equations

In this paper, two lattice Boltzmann models for two-dimensional coupled Burgers’ equations are proposed through treating the part or all of convection items as the source term, where the spatial gradient can be calculated by the distribution function. The models can exactly recover the Burgers’ equations without any assumptions. Some numerical tests are also performed to validate the present models. It is found that the proposed models are more accurate and efficient in solving two-dimensional coupled Burgers’ equations.     

山区输水管道工程的设计要点及陡坡直埋工艺

简要介绍了山区输水管道设计中常用的管道线路、管道材质、敷设方式、防冻方式及选取原则,重点介绍了一种适应山体陡坡段输水管直埋敷设的工艺。以供相关工程设计及施工人员借鉴。     

Effects of oxidised linoleic acid on the formation of Nε‐carboxymethyl‐lysine and Nε‐carboxyethyl‐lysine in Maillard reaction system

This study investigated the effects of oxidised linoleic acid (18:2) on N^ε‐carboxymethyl‐lysine (CML) and N^ε‐carboxyethyl‐lysine (CEL) formation in Maillard reaction systems. Model systems of lysine/glucose (L/G), lysine/18:2 (L/18:2), lysine/18:2/glucose (L/18:2/G), myofibrillar protein/glucose (MFP/G), MFP/18:2 and MFP/18:2/G were maintained at 37 °C for 6 weeks. The results showed that CML/CEL contents in L/G (6.99 and 0.96 mmol mol^?1 lysine, respectively) were significantly higher than those in L/18:2/G (1.43 and 0.41 mmol mol^?1 lysine, respectively), and there is a small amount of CML/CEL generation in L/18:2. However, the CML/CEL levels in MFP/G (197.2 and 83.8 ng mg^?1 protein, respectively) were markedly lower than those in MFP/18:2/G (283.2 and 118.5 ng mg^?1 protein, respectively). 18:2 favours the formation of CML/CEL in MFP/18:2/G, not in L/18:2/G. All these findings indicated that the role of 18:2 on CML/CEL formation in Maillard reaction system was complex, and depended on CML/CEL formation rate and substrate types (lysine or lysine residue in protein).     

Reducing deformation effect of tunnel with Non-Deformable Support System by Jointed Rock Mass Model

Numerical modeling has been used widely in mining and construction industries in recent years. The most important issue in engineering projects designed with numerical modeling is accurate modeling of rock mass behavior. If the rock mass behavior is modeled accurately, fewer problems will be faced during field application of projects. Selection of the true material model is a very important issue in numerical modeling for the tunnel projects. Non-Deformable Support System (NDSS), which will be mentioned in the scope of this research, does not mean that it does not permit any deformation or is a very stiff system. NDSS is a support system that does not permit deformations exceeding specified deformation amounts which are calculated with determination of the accurate rock mass behavior by the true material model and it must be evaluated with support system and excavation advance specifically. The origin of the paper is that numerical modeling provides more comfortable results in tunneling in case one can determine rock mass deformation and failure behavior appropriately. In (NDSS), however, support system element can only be determined by proper numerical modeling analysis. Moreover, deformation values determined by NDSS analysis are accepted as limit values. Therefore, applied support system should be within deformation tolerance limits determined by NDSS analysis. Briefly, this paper is related to NDSS that should be determined by numerical modeling analysis.In this research, in regard to the excessive deformations in T-35 tunnel which is one of the 33 tunnels of Ankara–Istanbul High-Speed Railway Project, results of the in situ measurements in the tunnel excavated with the new developed NDSS and results of the numerical model made with Jointed Rock Mass Model have been compared. It is determined that the results of the numerical modeling and the in situ measurements are very consistent with each other.