Abstract: Laser welding of 1A90 pure aluminum and ZL114A aluminum alloy with powder under the same laser welding parameters were carried out in this work. The relation between weld elements and solidification cracking formation of these two materials was investigated in the perspective of metallurgical factor. And the alloy element contents and distribution near the cracks were determined by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS). Then the concept of weld element equivalent was introduced comparing with the carbon equivalent expression. The weld element equivalent expressions were established by using mathematics regress. And the verified results indicate that the weld element equivalent expressions can properly forecast the formation of solidification cracking.

Abstract: Part of work on CFD simulations by the high-lift system design team in Fudan university for large civil aircraft is presented. The research on CFD simulation of the high-lift systems and some concepts and experience in three-dimensional geometry modeling are also presented, which are done on the self-developed platform of high-lift device aerodynamic calculation software and programs. For which, the design efficiency is substantially improved.

Abstract: Many efforts have been taken to achieve automated Graphical User Interface (GUI) testing. The most popular way is model-based testing, which supports automated test case generation and execution. But building such a model is a non-trivial task, which usually costs the most work-load in the entire testing process. Most of the approaches about automated model deriving are dependant on the programming language or specific OS. In this paper, we proposed a new approach of GUI modeling using Optical Character Recognition (OCR), and technical poblems encountered have been analyzed in deatail. Case study shows that our approach is capable of analyzing most of the GUI windows, and generating corresponding model and hence eliminates the above constraint.

Abstract: P-i-N (PIN) diodes and avalanche photo-diodes (APD) are the most commonly used photo-detectors in terrestrial FSO systems. In this paper, we review the photo-detection process for the cases of PIN- and APD-based receivers and provide a comprehensive study of different noise sources that affect signal detection in an FSO system. We present a complete and precise model for the receiver noise by taking different receiver parts into account. In particular, we study the impact of thermal, shot, background, and transmitter noises on the receiver performance by considering practical and realistic case studies. We bring clearance on the impact of the interaction of signal and background noise due to non-linear characteristic of the photo-detector, and on the role of the trans-impedance load resistance. We discuss the dominant noise components for the cases of using a PIN or an APD, and compare their performances at the presence or not of background radiations.