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81.
A simple efficient method is proposed to reduce the total number of triangles in an isosurface extraction method based on tetrahedral decomposition. We slightly perturb the input volumetric data so that useless small and thin triangles are removed. The perturbed volumetric data contain the exact isovalues from which a mesh is extracted. Since the proposed method is a pre-process of an isosurface extraction, it is not necessary to modify the mesh structure unlike the other similar methods. 相似文献
82.
Jeong-Won Yoon Hyun-Suk Chun Ja-Myeong Koo Seung-Boo Jung 《Microsystem Technologies》2007,13(11-12):1463-1469
As an alternative to the time-consuming solder pre-forms and pastes currently used, a co-electroplating method of eutectic Au–Sn alloy was used in this study. Using a co-electroplating process, it was possible to plate the Au–Sn solder directly onto a wafer at or near the eutectic composition from a single solution. Two distinct phases, Au5Sn (ζ-phase) and AuSn (δ-phase), were deposited at a composition of 30 at.%Sn. The Au–Sn flip-chip joints were formed at 300 and 400°C without using any flux. In the case where the samples were reflowed at 300°C, only an (Au,Ni)3Sn2 IMC layer formed at the interface between the Au–Sn solder and Ni UBM. On the other hand, two IMC layers, (Au,Ni)3Sn2 and (Au,Ni)3Sn, were found at the interfaces of the samples reflowed at 400°C. As the reflow time increased, the thickness of the (Au,Ni)3Sn2 and (Au,Ni)3Sn IMC layers formed at the interface increased and the eutectic lamellae in the bulk solder coarsened. 相似文献
83.
The interfacial reactions and ball shear properties of ball grid array (BGA) solder joints aged at 170 °C for up to 21 days were investigated with different displacement rates. Two different kinds of solders, Sn–37Pb and Sn–3.5Ag (all wt.%), and an electroplated Ni/Au BGA substrate were employed in this work. A continuous Ni3Sn4 intermetallic compound (IMC) layer was formed at the interfaces between both the Sn–37Pb and Sn–3.5Ag solders and the substrate during reflow. After aging, two different reaction layers, consisting of (AuxNi1−x)Sn4 IMC and Pb-rich phase, were additionally observed between the Sn–37Pb solder and the Ni3Sn4 IMC layer. The thicknesses of these interfacial reaction layers increased with increasing aging time. After reflow, all the fractures occurred inside the bulk solder. The fracture location of the Sn–37Pb solder joints was shifted toward the solder/Ni interface with increasing aging time and displacement rate, whereas the fracture of the Sn–3.5Ag solder joints mainly occurred inside the bulk solder, irrespective of the aging time and displacement rate. Consequently, the shear properties of the Sn–37Pb solder joints significantly decreased with increasing aging time, whereas those of the Sn–3.5Ag solder joints slightly decreased. The tendency toward brittle fracture of the Sn–37Pb solder joints was intensified with increasing displacement rate. The shear properties of the ductile solder joints increased with increasing displacement rate, while the displacement until fracture, deformation energy and displacement rate sensitivity of the brittle solder joints significantly decreased with increasing displacement rate. 相似文献
84.
Jayong Koo Qing Cai Muchaidze G. Martwick A. Kai Wang Pommerenke D. 《Electromagnetic Compatibility, IEEE Transactions on》2007,49(3):504-511
A method for analyzing electrostatic discharge (ESD) generators and coupling to equipment under test in the frequency domain is proposed. In ESD generators, the pulses are excited by the voltage collapse across relay contacts. The voltage collapse is replaced by one port of a vector network analyer (VNA). All the discrete and structural elements that form the ESD current pulse and the transient fields are excited by the VNA as if they were excited by the voltage collapse. In such a way, the method allows analyzing the current and field-driven linear coupling without having to discharge an ESD generator, eliminating the risk to the circuit and allowing the use of the wider dynamic range of a network analyzer relative to a real-time oscilloscope. The method is applicable to other voltage-collapse-driven tests, such as electrical fast transient, ultrawideband susceptibility testing but requires a linear coupling path. 相似文献
85.
Scanning probe lithography (SPL) has considerable potential for producing small features (<100 nm) with a high spatial precision, and would be useful for fabricating 2-dimensional (2D) structures. However, it has not been used successfully in the fabrication of 3-dimensional (3D) structures due to the low aspect ratio of the resulting feature. Herein, we describe a simple 3D pattering method with repeated SPL, in which precise layer-by-layer alignment is not needed. Results and processes of the pattern can be readily observed in real-time. Using the proposed method, we successfully fabricated a 3D pyramidal structure. Additional growth for repeated oxidation was observed due to the superposition of energy absorbed on the pre-oxidized species. 相似文献
86.
Yeonjong Koo Ekaterina Y. Lukianova‐Hleb Joann Pan Sean M. Thompson Dmitri O. Lapotko Janet Braam 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(5):623-630
Biological responses to photothermal effects of gold nanoparticles (GNPs) have been demonstrated and employed for various applications in diverse systems except for one important class – plants. Here, the uptake of GNPs through Arabidopsis thaliana roots and translocation to leaves are reported. Successful plasmonic nanobubble generation and acoustic signal detection in planta is demonstrated. Furthermore, Arabidopsis leaves harboring GNPs and exposed to continuous laser or noncoherent light show elevated temperatures across the leaf surface and induced expression of heat‐shock regulated genes. Overall, these results demonstrate that Arabidopsis can readily take up GNPs through the roots and translocate the particles to leaf tissues. Once within leaves, GNPs can act as photothermal agents for on‐demand remote activation of localized biological processes in plants. 相似文献
87.
Ig Mo Koo Tran Duc Trong Yoon Haeng Lee Hyungpil Moon Jachoon Koo Sun Kyu Park Hyouk Ryeol Choi 《Journal of Intelligent and Robotic Systems》2013,72(1):57-72
In this paper, we present a wall climbing robot system, called “LARVA”, developed for visual inspection of structures with flat surfaces. The robot has two differential driving wheels with a suspension and an adhesion mechanism. The adhesion mechanism is composed of an impeller and two–layered suction seals. It is designed to provide sufficient adhesion force and be controlled so that the robot can move freely on various wall surfaces. The static and aerodynamic modeling of the adhesion mechanism is given and the analysis of the adhesion mechanism, air leakage, and inner flow are carried out to be useful for the design as well as the control. Finally, the performances of the robot are experimentally verified on several kinds of walls and its feasibility is validated. 相似文献
88.
Young-Boo Son Seung Hoon Shin Sang-Hoon Ji Yeon-Sun Choi Ja Choon Koo 《Microsystem Technologies》2013,19(9-10):1433-1440
Misalignment of mechanical rolling elements such as belt and pulley causes catastrophic malfunctions of high speed paper feeding systems like automated teller machines (ATMs), printers, and copy machines. A combination of a crown pulley and a belt can be an effective self-alignment mechanism for the systems. In this paper, an equation of motion of the belt and pulley system is driven, verification tests are carried out, and a design improvement strategy is suggested for high speed paper media transport systems. 相似文献
89.
Sang Ho Lee Hye Young Koo Dae Soo Jung Jang Heui Yi Yun Chan Kang 《Ceramics International》2009,35(7):2651-2657
Fine-sized BaMgAl10O17:Eu2+ phosphor powders with plate-like morphology were prepared by spray pyrolysis process. The effects of ratio of BaF2 and Ba(NO3)2 used as the source materials of Ba component on the morphological and optical properties of the BaMgAl10O17:Eu2+ phosphor powders were investigated. BaF2 was used as the flux material as well as the source material of Ba component. The phosphor powders prepared from the spray solution with the same mole concentrations of BaF2 and Ba(NO3)2 had fine size, plate-like morphology and narrow size distribution. The addition of BaF2 as the source material of Ba component increased the photoluminescence intensities of the phosphor powders. The phosphor powders prepared from the spray solution with the ratios of BaF2 and Ba(NO3)2 larger than 1 had the similar photoluminescence intensities to that of the commercial product. 相似文献
90.