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181.
Rongshan Qin Yongkun Luo Bernadette Elliott-Bowman Osamudiamen Omoigiade 《Materials Science & Technology》2018,34(1):29-34
This work reports the refinement of pearlite structure into nanostructure using electropulsing. Nanostructured pearlitic steel wires possess nanoscale lamellae or nanoscale grain microstructures. Fabrication of nanostructures by severe plastic deformation and lamellar to grain transformation have been investigated. It is suggested that an aligned pearlite structure is preferred in severe plastic deformation. The lamellar to grain transformation is controlled by diffusion of carbon within cementite and also from cementite to ferrite phases. Carbon mobility is changed by mechanical, thermal and electrical states. The interface between nanoscale sub-grains in the ferrite phase has considerable carbon content. Numerical calculations and experimental observations demonstrated these mechanisms. 相似文献
182.
Experimental results on exploding tungsten wires in air at atmospheric pressure at current densities 107 A·cm–2 and a current rise 1010 A·s–1 are presented. Besides the current through the probe and the voltage across it, the diameter of the wire material and its surface temperature have been measured. The final aim of this investigation is the determination of the thermophysical properties of a high-melting liquid metal up to its critical point. Here a first step should be made to demonstrate the reliability of the method and to justify the crucial assumptions. To determine the limits for the applicability of a homogeneous approach used so far, a one-dimensional numerical model in Z-pinch geometry has been used which gives the time evolution of the profiles of temperature, density, and pressure across the wire. The model describes well the main features observed in these experiments. A physical explanation for the maximum in the time dependences of the surface temperature is proposed. This behavior is related to special thermodynamic properties of a two-phase (liquid–gas) mixture forming in a peripheral layer around the liquid metal. The temperature limit is determined for which there are no remarkable gradients of temperature and density across the wire. The specific heat, the thermal expansion coefficient, and the electrical as well as thermal conductivity of liquid tungsten can now, in principle, be obtained. The parameters of the critical point of the liquid-vapor phase transition can also be estimated. 相似文献
183.
本文分析了由国外引进的线缆设备电控系统中的速度控制、连续退火、温度控制、微机检测、变频调速等几个关键技术,并与国产设备作了对比。本文有助于消化吸收新技术、改造旧设备、研制新设备。 相似文献
184.
本文采用添加适量稀土元素与微合金化的办法,研制出一类新的导电铝排材料。这类材料与常规的热挤压导电铝排材料相比,强度提高了40%至60%.而电阻率又符合国家标准要求,且具有良好的加工性能.为国内外先进水平。其次,本文还从理论上较好地分析了新材料性能提高的作用机理。 相似文献
185.
The vascular corrosion casting technique produces a replica of vascular beds of normal or pathological tissues. Once associated with scanning electron microscopy (SEM), this technique provides details of the three-dimensional anatomic arrangement of the vascular replica, which is the main advantage of this method. The present study is intended to describe the steps of the vascular corrosion casting technique and the different ways to perform them. them. 相似文献
186.
Huiyun Xiao Shengbin Li Zidong He Yuanzhao Wu Zhiyi Gao Chao Hu Siqi Hu Shengding Wang Chao Liu Jie Shang Meiyong Liao Denys Makarov Yiwei Liu Run-Wei Li 《Advanced functional materials》2023,33(16):2214907
Strain and temperature are important physiological parameters for health monitoring, providing access to the respiration state, movement of joints, and inflammation processes. The challenge for smart wearables is to unambiguously discriminate strain and temperature using a single sensor element assuring a high degree of sensor integration. Here, a dual-mode sensor with two electrodes and tubular mechanically heterogeneous structure enabling simultaneous sensing of strain and temperature without cross-talk is reported. The sensor structure consists of a thermocouple coiled around an elastic strain-to-magnetic induction conversion unit, revealing a giant magnetoelastic effect, and accommodating a magnetic amorphous wire. The thermocouple provides access to temperature and its coil structure allows to measure impedance changes caused by the applied strain. The dual-mode sensor also exhibits interference-free temperature sensing performance with high coefficient of 54.49 µV °C−1, low strain and temperature detection limits of 0.05% and 0.1 °C, respectively. The use of these sensors in smart textiles to monitor continuously breathing, body movement, body temperature, and ambient temperature is demonstrated. The developed multifunctional wearable sensor is needed for applications in early disease prevention, health monitoring, and interactive electronics as well as for smart prosthetics and intelligent soft robotics. 相似文献
187.
188.
Using the boundary element dual reciprocity method-multi-domain (DRM-MD) a bound electron states and corresponding wave functions in semiconductor quantum wires embedded in a matrix were considered. The single circular and rectangular as well as the two near circular quantum wires were analyzed. In the case of two coupled quantum wires the dependence of the resulting wave function and eigenenergies as a function of the distance between wires was calculated. The DRM-MD gave a linear electron state model and developed numerical approach accurately captured the symmetry breaking and splitting of the degenerated energy states due to presence of additional wire. According to the symmetry of the structures a suitable mesh reduction was employed and different modes were considered separately. For a case of hetero-structures domain decomposition was used. 相似文献
189.
介绍了国内及宝钢目前低合金焊丝用线材的现状及存在的问题,并针对线材冷却工艺进行了重点分 析讨论,通过对比试验找出降低线材原始抗拉强度的冷却工艺。以BH08MnMoTiB为例。采用这种工艺轧制的 线材抗拉强度控制在770MPa左右。 相似文献
190.
The deformation microstructure evolution of single crystal copper wires produced by OCC method has been studied with the help
of TEM, EBSD and OM. The results show that there are a small number of dendrites and twins in the undeformed single crystal
copper wires. However, it is difficult to observe these dendrites in deformed single crystal copper wires. The structure evolution
of deformed single crystal copper wires during drawing process can be divided into three stages. When the true strain is lower
than 0.94, macroscopic subdivision of grains is not evident, and the microscopic evolution of deformed structure is that the
cells are formed and elongated in drawn direction. When the true strain is between 0.94 and 1.96, macroscopic subdivision
of grains takes place, and the number of microbands located on {111} and cell blocks is much more than that with the true
strain lower than 0.94. When the true strain is larger than 1.96, the macroscopic subdivision of grains becomes more evident
than that with the true strain between 0.94 and 1.96, and S-bands structure and lamellar boundaries will be formed. From EBSD
analysis, it is found that part of 〈100〉 texture resulting from solidifying is transformed into 〈111〉 and 〈112〉 due to shear
deformation, but 〈100〉 texture component is still kept in majority. When the true strain is 0.94, the misorientation angle
of dislocation boundaries resulting from deformation is lower than 14°. However, when the true strain arrives at 1.96, the
misorientation angle of some boundaries will be greater than 50°, and the peak of misorientation angle distribution produced
by texture evolution is located in the range between 25° and 30°.
Supported by the National Natural Science Foundation of China (Grant Nos. 50471098 and 59971033), the Natural Science Foundation
of Shaanxi Province, China (Grant No. 2003E101), and the Teaching and Research Award Program for Outstanding Young Teachers
in Higher Education Institution of MOE, China 相似文献