Correlation between the interfacial reaction and mechanical joint strength of the flip chip solder bump during isothermal aging

The interfacial microstructure of Sn-37Pb solder with immersion Au/electroless Ni-P under bump metallization (UBM) was studied using scanning electron microscopy (SEM) and electron probe micro analyzer (EPMA). A Ni₃Sn₄ intermetallic compound (IMC) layer was formed at the interface between the solder and Ni-P UBM upon reflow. However, after thermal aging, AuSn₄ containing a certain amount of Ni dissolved in it, i.e. (Au,Ni)Sn₄, appeared above the Ni₃Sn₄ layer. The shear force of the joints decreased with the aging period. The decrease of the shear force could be mainly caused by the coarsening effect of the microstructure within the solder, while the decrease after prolonged aging time should be due to the excessively grown IMC layer. A simple computational simulation was employed to interpret the failure mechanism of the shear tested specimens using finite element modeling (FEM). The FEM results explained well the ductile failure mode of the nearly whole tested joints.     

A framework for sharing product information across enterprises

Collaborative product commerce (CPC) is a newly emerging technology to support inter-enterprise collaboration through the product life-cycle. From the point of view of information technology, CPC is a software technology to integrate products, processes and resources of different enterprises using web technologies. In this paper, we propose a framework for integrating product information across enterprises, which is being developed by the Electronics and Telecommunications Research Institute (ETRI) as a part of a CPC project. The product metadata represented by an XML schema, which is compatible with the ISO STEP PDM (product Data Management) schema standard, is presented to semantically and schematically integrate distributed product information. Web services technologies are discussed to support the interoperability of application systems related to the product development, such as computer-aided design (CAD) and PDM, where most of these applications run in a distributed environment. Finally, we implement the framework to integrate distributed product information and application systems.     

KAIST image computing system (KICS): A parallel architecture for real-time multimedia data processing

An efficient parallel architecture is proposed for high-performance multimedia data processing using multiple multimedia video processors (MVP; TMS320C80), which are fully programmable general digital signal processors (DSP). This paper describes several requirements for a multimedia data processing system and the system architecture of an image computing system called the KAIST Image Computing System (KICS). The performance of the KICS is evaluated in terms of its I/O bandwidth and the execution time for some image processing functions. An application of the KICS to the real-time Moving Picture Expert Group 2 (MPEG-2) encoder is introduced. The programmability and the high-speed data-access capability of the KICS are its most important features as a high-performance system for real-time multimedia data processing.     

Carpesium abrotanoides extract inhibits inducible nitric oxide synthase expression induced by toll-like receptor agonists

Inflammation is a pathological and physiological process which is known to be involved in numerous diseases, while it is notable that a considerable proportion of chronic inflammatory diseases overlap with the development of cancer. One of the most important proteins for inflammatory responses is inducible nitric oxide synthase (iNOS). The present study investigated the effect of the extract of Carpesium abrotanoides L. (ECA) on inflammation by modulating iNOS expression induced by toll-like receptors (TLRs) agonists in murine macrophages. ECA suppressed iNOS expression induced by lipopolysaccharide (TLR4 agonist), macrophage-activating lipopeptide 2-kDa (TLR2 and TLR6 agonist), and polyriboinosinic polyribocytidylic acid (TLR3 agonist). All the results suggest that ECA can modulate TLR signaling pathways and subsequent chronic inflammatory responses.     

Brittle–Ductile Transition and Dislocation Mobility in Sapphire

The brittle-to-ductile transition (BDT) of Precracked sapphire in four-point bending was studied as a function of orientation and strain rate from room temperature to 1500°C. Plastic deformatiom of sapphire occurs via basal and prismatic slip during loading at high temperature (above 1030–1100°C, depending on orientation). The BDT temperature, T_c , varies with strain rate and crystallographic orientation of the fracture plane. The activation, derived from the strain rate variation of T_c , is approximately energy of the process controllingh the BDT in sapphire, derived from the strain rate variation of T_c is sapproximately 3.2 eV, close to that for dislocation glide. In one specimen orientation, "warm-prestressing" increases the room-temperature fracture stress.     

Solid state intermetallic compound layer growth between Sn-8Zn-3Bi solder and bare copper substrate

The growth kinetics of the intermetallic compound layer formed between Sn-8Zn-3Bi solder and a bare Cu substrate by solid-state isothermal aging were examined at temperatures between 343 and 423 K for periods ranging from 0 to 100 days. A quantitative analysis was performed of the intermetallic compound layer thickness as a function of the aging time and aging temperature. For the identification of the intermetallic compounds, both Energy Dispersive X-ray and X-Ray Diffraction were employed.The experimental results showed that the γ -Cu₅Zn₈ intermetallic compound was observed at the interface between the solder and the bare copper substrate. Additionally, the thickness of the γ -Cu₅Zn₈ intermetallic compound increased with increasing aging temperature and aging time. The layer growth of the intermetallic compound in the Cu/Zn couple follow a parabolic law within a given temperature range. As a whole, because the value of the time exponent (n) is approximately equal to 0.5, the layer growth of the intermetallic compound was mainly controlled by the diffusion mechanism in the temperature range studied. The apparent activation energy of the γ -Cu₅Zn₈ intermetallic compound was 61.19 kJmol.     

Motion estimation using low-band-shift method for wavelet-basedmoving-picture coding

The discrete wavelet transform (DWT) has several advantages of multiresolution analysis and subband decomposition, which has been successfully used in image processing. However, the shift-variant property is intrinsic due to the decimation process of the wavelet transform, and it makes the wavelet-domain motion estimation and compensation inefficient. To overcome the shift-variant property, a low-band-shift method is proposed and a motion estimation and compensation method in the wavelet-domain is presented. The proposed method has a superior performance to the conventional motion estimation methods in terms of the mean absolute difference (MAD) as well as the subjective quality. The proposed method can be a model method for the motion estimation in wavelet-domain just like the full-search block matching in the spatial domain.     

Eupatorium japonicum extract regulates inflammation through suppression of the TRIF-dependent signaling pathway of toll-like receptors

Inflammation can be mediated by invading microbial pathogens. Toll-like receptors (TLRs) recognize invading microbial pathogens, inducing innate immune responses. Broadly, the activation of TLRs induces two major downstream signaling pathways, myeloid differential factor 88 (MyD88)- and Toll/interleukin 1 receptor domain-containing adapter inducing interferon-β (TRIF)-dependent pathways, which lead to the activation of nuclear factor-κB (NF-κB) and interferon regulatory factor 3 (IRF3). To evaluate the therapeutic potential of the ethanol extracts of flowers of Eupatorium japonicum Thunb (EJE), its effect on signal transduction via the TLR signaling pathways induced by lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly[I:C]) was examined. EJE suppressed the activation of NF-κB and IRF3 induced by LPS or poly[I:C]. EJE also inhibited LPS- or poly[I:C]-induced IRF3 phosphorylation as well as interferon-inducible genes, such as interferon inducible protein-10. These results suggest that EJE can modulate TLR signaling pathways, realizing effective therapeutic options for chronic inflammatory diseases.     

Costunolide inhibits interferon regulatory factor 3 activation induced by lipopolysaccharide and polyinosinic-polycytidylic acid

Inflammation can be initiated by invading microbial pathogens. Toll-like receptors (TLRs) recognize molecular structures derived from microbial pathogens and regulate the activation of innate immunity. In general, TLRs have 2 major downstream signaling pathways, the myeloid differentiation primary response protein 88 (MyD88)- and Toll/interleukin 1 receptor (TIR) domaincontaining adaptor protein (TIRAP) inducing interferon (TRIF)-dependent pathways, which lead to the activation of nuclear factor (NF)-κB and interferon regulatory factor 3 (IRF3). Costunolide, one of the active ingredients in Aucklandiae Radix (Saussurea lappa), has been used to treat many chronic inflammatory diseases. To evaluate the therapeutic potential of costunolide, its effect on signal transduction via the TLR signaling pathways was examined. Costunolide inhibited lipopolysaccharide or polyinosinicpolycytidylic acid-induced NF-κB and IRF3 activation and IRF3 phosphorylation, as well as interferon-inducible genes such as interferon inducible protein-10. The results suggest that costunolide can modulate immune responses regulated by TLR signaling pathways and may be the basis of effective therapeutics for chronic inflammatory diseases.