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131.
《Journal of Materials Processing Technology》2014,214(5):1136-1142
Stainless steel alloy 316 weld samples were subjected to spot gas tungsten arc welding at 1G (G = 9.8 m/s2) and 3.6G accelerations. The cross sections of the fusion zones were polished, etched, and measured in order to perform measurements on the microstructure. Measurement and observation results indicated that increasing in buoyancy driven flow produced wider but shallower welds during spot GTA welding. Tensile testing showed no noticeable differences in peak loads between samples welded at 1G and 3.6G. Tensile ductility was lightly less for the 3.6G samples. 相似文献
132.
Till now,water based lubricants,especially aqueous solutions,have not been employed in the elastohydrodynamic lubrication(EHL)due to their poor film forming capability or low wear resistance.In this paper,we proposed a method to develop water based lubricant:employing polyalkylene glycol solution as base stock to improve EHL film forming capability and using organic phosphate ester(DPZ)as anti-wear additive to improve wear resistance property.The lubricating properties of the mixed solutions,including load carrying capability,wear resistance property,friction reduction property,EHL film forming behavior,were investigated.The experimental results indicate that the mixed solution presents excellent lubricating properties,which make it a promising candidate in developing water based lubricants. 相似文献
133.
The Ni-33Al-28Cr-6Mo-0.3Hf near eutectic alloy was treated in a 10 T strong magnetic field at 1073 K and 1173 K for 1.5 h respectively. Microstructure examination reveals that after the strong magnetic field treatment, most Ni2AlHf Heusler particles have changed into Hf solid solution, and moreover Hf solid solution and Heusler particles along eutectic cell boundaries distribute more uniformly. In addition, the eutectic cellular microstructure of the alloy with strong magnetic field treatment at 1173 K is changed greatly. The eutectic cell has an obvious disintegration and Cr(Mo) plates become coarsening and spheroidizing. The compression tests show that room temperature compressive ductility of the alloys with strong magnetic field treatment improves significantly, compared with the heat-treated alloy. 相似文献
134.
通过在主蒸汽释放系统隔离阀中应用以可靠性为中心的维修(RMC)方法,识别出该设备的所有失效模式,尽快判断出灾害性的失效,在设计时采取措施降低或者避免事故发生的频率。 相似文献
135.
Yang Jian 《中兴通讯技术(英文版)》2010,8(3):5-8
Global operators are in the process of constructing next generation IP packet-switched networks, with the view of moving towards full IP-based networks. As data services increase, improvements in bandwidth, Quality of Service (QoS), Operation Administration and Maintenance (OAM), and network reliability are required. Convergence of network data transmission and network communications technology has been driven by converged IP services (including video, voice, and data), and unified multi-service load demand. Packet Transport Networking (PTN) has come into being to meet these requirements, and PTN Standards are being developing rapidly. 相似文献
136.
《Pattern recognition》2005,38(10):1705-1716
The appearance of a face will vary drastically when the illumination changes. Variations in lighting conditions make face recognition an even more challenging and difficult task. In this paper, we propose a novel approach to handle the illumination problem. Our method can restore a face image captured under arbitrary lighting conditions to one with frontal illumination by using a ratio-image between the face image and a reference face image, both of which are blurred by a Gaussian filter. An iterative algorithm is then used to update the reference image, which is reconstructed from the restored image by means of principal component analysis (PCA), in order to obtain a visually better restored image. Image processing techniques are also used to improve the quality of the restored image. To evaluate the performance of our algorithm, restored images with frontal illumination are used for face recognition by means of PCA. Experimental results demonstrate that face recognition using our method can achieve a higher recognition rate based on the Yale B database and the Yale database. Our algorithm has several advantages over other previous algorithms: (1) it does not need to estimate the face surface normals and the light source directions, (2) it does not need many images captured under different lighting conditions for each person, nor a set of bootstrap images that includes many images with different illuminations, and (3) it does not need to detect accurate positions of some facial feature points or to warp the image for alignment, etc. 相似文献
137.
《Solid-state electronics》2006,50(7-8):1183-1188
Thyristors able to block 4 kV have been fabricated and characterised. The experimental forward current is 1.3 A @ VAK = 10 V for a 9 mA gate current during 550 ns. The device active area is 2.3 mm2. The devices and their edge terminations have been designed using numerical simulations. Two different edge terminations have been envisaged (mesa and a combination of mesa and JTE). A SiO2 passivation layer also improves the forward blocking voltage depending on the sign and the magnitude of the effective charge density in the oxide. The mesa protection is not enough to allowing the thyristor to block 5 kV, due to the low etching rate in SiC. Thus, a mesa/JTE protection has been used. The influence of the etching depth, the JTE dose and length on the forward blocking voltage of the thyristor has been studied in details. Simulation results have allowed designing the devices, not far from the optimal structure. The best results of the forward blocking voltage are 4 kV for the mesa protected thyristor, while the mesa/JTE combination yields 3.6 kV. Furthermore, experimental results confirm the simulations concerning the influence of the oxide thickness on the forward blocking voltage. The better results for the mesa protected thyristor are due to a lower interface SiC/SiO2 charge density provided by the different oxidation processes (at different foundries).In addition, the comparison between experiments and simulations allows estimate the effective charge density of the SiO2 layer in 1012–5 × 1012 cm−2 range for the two fabricated thyristors. The improvement in the forward blocking voltage must pass through an improvement of the passivation layer. Passivation still remains a technological key step to obtain SiC high-voltage devices. 相似文献
138.
LED全彩显示屏配光解决方案 总被引:1,自引:0,他引:1
介绍了LED全彩显示屏基于最主要部件-LED的全套配光方案,包括投产晶片的K-factor管理、封装工艺的控制、白平衡的调节以及LED光学透镜的设计,代表着业界先进的配光解决理念。 相似文献
139.
详细介绍了利用P89LPC932A1单片机实现微功耗嵌入式指纹锁的设计思路和方法.根据单片机P89LPC932A1高集成度和完全掉电工作模式的低功耗的优点,给出了完善的软硬件设计方案,非常适合于电池供电和空间受限的工作环境以及便携式、嵌入式应用场合. 相似文献
140.