Automated X‐ray inspection method for fillet‐less mounted chip components

Chip components mounted on the printed circuit board are rapidly being miniaturized. Furthermore, the fillet‐less chip soldering technique, which does not use a solder fillet, is widely used in portable products such as mobile phones. However, there is no method to inspect the soldering of fillet‐less chip mounting. In this paper, we propose an automated X‐ray inspection technique for fillet‐less chip mounting. It extracts three inspection parameters from the X‐ray image. In the experiments, we evaluate the repeatability and inspecting ability of the technique and confirm that sufficient information for failure detection is obtained. An automated X‐ray inspection system using this technique is now in operation at some factories, so in conclusion our automated method would be useful in practice. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

活性硅醇与ENR开环反应及对硫化胶力学性能的影响

以过氧羧酸为环氧化剂,制得环氧化天然橡胶(ENR)。通过从水玻璃中提取的活性硅醇与ENR的开环反应,得到含硅杂化材料ENR-SiO2,测试了其对NE硫化胶力学性能的影响,发现含硅杂化材料对NR硫化胶有明显的增强作用。     

Preparation of micron-scale monodisperse oil-in-water microspheres by microchannel emulsification

Micron-scale monodisperse oil-in-water (O/W) micropheres (MS) were prepared using a novel microchannel (MC) emulsification technique. The characteristics of the MS preparation and the O/W-MS prepared were studied. Soybean oil and medium-chain triacyglycerol (MCT) were used as the disprrsed phase, and physiological saline was used as the continuous phase. Silicon MC with 1 to 3μm-equivalent channel diameters were employed. A novel MC module was devised to easily recover the O/W-MS prepared. The effects of the channel shape on the behavior of MS formation, on the MS size, and on the distribution were investigated. An MC with a terrace at the MC outlet stably yielded micron-scale monodisperse O/W-MS; the MS had diameters of about 5 μm, and their coefficients of variation were below 9%. Monodisperse food-grade O/W-MS with diameters of about 4 μm could be obtained by using polyglycerol fatty acid ester as the surfactant. The size and size distribution of the recovered O/W-MS remained almost constant over 60 d, demonstrating their long-term stability.     

Continuous emulsion polymerization of styrene in a single Couette–Taylor vortex flow reactor

The effect of the geometrical and operational parameters on the mixing characteristics of a Couette–Taylor vortex flow reactor (CTVFR) were investigated and were correlated with the same parameters by using the tank‐in‐series model. Continuous emulsion polymerization of styrene was conducted at 50°C in a CTVFR to clarify the effects on kinetic behavior and reactor performance of operational parameters such as rotational speed of inner cylinder (Taylor number), reactor mean residence time, and emulsifier and initiator concentrations in the feed streams. It was found that steady‐state monomer conversion and particle number could be freely varied only by varying the Taylor number. In order to explain the observed kinetic behavior of this polymerization system, a mathematical model was developed by combining the empirical correlation of the mixing characteristics of a CTVFR and a previously proposed kinetic model for the continuous emulsion polymerization of styrene in continuous stirred tank reactors connected in series (CSTRs). On the basis of these experimental results, it was concluded that a CTVFR is suitable for the first reactor (prereactor) of a continuous emulsion polymerization reactor system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1931–1942, 2001     

Large-area uniform dust-free plasma CVD

In the weak magnetic field perpendicular to the discharge electric field, both the electrons and positive ions are transported in the direction of E×B drift by the space charge electric field produced by the preceded electrons. As a result, radicals are generated uniformly outside of discharge space between the electrodes in the direction of E×B drift. On the other hand, negatively charged heavy particles such as dust particles can be removed from discharge space in the direction opposite to E×B drift of plasmas. The authors have studied the transport mechanisms of magnetized dusty plasmas and its applications for the large-area uniform a-Si:H thin film deposition in plasma CVD methods. This paper reviews the transport phenomena and the transport mechanisms of dust particles and the results of film preparation under particle-free process conditions.     

Sulfidation Properties of Ni–20Cr and Ni–13.5Co–20Cr Alloys at 873 K under Low Sulfur Pressures in H2S-H2 Atmospheres

The sulfidation properties of Ni–20Cr and Ni–13.5Co–20Cralloys as well as a nickel-base superalloy AISI685 were investigated at873 K in H₂S–H₂ gas mixtures with sulfur partial pressures of10^–4, 10^–5.5, and 10^–7Pa by mass-gain measurements,electron-probe microanalysis (EPMA), and X-ray diffraction (XRD)analysis. Sulfidation obeyed the parabolic rate law, and the parabolic rateconstants decreased in the order Ni–20Cr, Ni–13.5Co–20Cr,and AISI685 at each sulfur pressure. With decreasing sulfur pressure, therate constants first decreased slowly and then rapidly at a 10–7 Pasulfur pressure. At both 10^–4 and 10^–5.5 Pa sulfur pressures,Ni–20Cr formed a surface scale with a duplex structure of inner(Cr₃S₄) and outer (Ni₃S₂) layers, while Ni–13.5Co–20Cr formeda triplex structure of inner (Cr₃S₄), intermediate(Ni,Co)Cr₂S₄, and outer[Ni₃S₂+(Co,Ni)₉S₈] layers. Thesurface scale formed on AISI685 was verycomplex, comprising at least four layers, a fibrous (Co,Ni)₉S₈ top surface,outer [Ni₃S₂+(Co,Ni)₉S₈], and intermediate [(Cr,Ti)₃S₄] layers, as well asan inner layer containing Cr, Ti, Mo, Al, and S. At the 10^–7 Pa sulfurpressure, which is lower than the dissociation pressure of Ni₃S₂, bothNi–20Cr and Ni–13.5Co–20Cr formed a surface scale ofCr₃S₄ covered by a thin NiCr₂S₄ layer, accompanied by copious internalsulfidation of Cr₃S₄ and/or CrS. On AISI685 there was a surface scale of(Cr,Ti)₃S₄ accompanied by the usual internal sulfidation. It is discussedthat diffusion of cations in the inner Cr₃S₄ layer is the rate-determiningstep for the growth of the multilayer structures. At the 10^–7 Pasulfur pressure, diffusion of Cr and S contribute to form a thin surfacescale and internal sulfidation, respectively.     

Fabrication of heterostructures of halogen-bridged quasi-one-dimensional mixed-valence transition metal complexes

Single-heterostructure crystals of a series of halogen-bridged quasi-one- dimensional mixed-valence transition metal complexes (HMMCs) were fabricated by selective coordination epitaxial growth (SCE growth). The overgrowth crystals of the HMMC were grown on the columnar crystals of the substrate HMMC in solution. The single-heterostructure crystals were epitaxially grown only when the two HMMCs had similar crystal structures. If their crystal structures were different, no heterostructure crystal was grown. This result suggests that the degree of mismatch between the crystal structures of the substrate and the overgrowth is the predominant factor which determines the SCE growth of the HMMCs.     

Damage evolution behavior of CFRP laminates under post-impact fatigue with water absorption environment

In this study, the damage evolution behavior was evaluated considering the effect of the textile structure and water absorption. Damage observation was conducted by the integration of non-destructive and direct observation methods. Candidate textile reinforcements were T300-3k plain woven fabric (PW) and T700S-12k multi-axial knitted fabric (MA). The effect of water absorption on the performances of compression after impact (CAI) and PIF were small in PW CFRP laminates. Conversely, PIF properties of water-absorbed MA CFRP laminates drastically decreased than that of dry ones. CAI strength was not affected by water absorption. PIF performance of dry MA CFRP was fairly higher than that of the others. From the precise observation, some evidences of interfacial deterioration caused by water absorption were confirmed in both PW and MA CFRP laminates.     

A versatile planar QCM-based sensor design for nonlabeling biomolecule detection

Despite high theoretical sensitivity, low-cost manufacture, and compactness potentially amenable to lab-on-a-chip use, practical hurdles have stymied the application of the quartz crystal microbalance (QCM) for aqueous applications such as detection of biomolecular interactions. The chief difficulty lies in achieving a sufficiently stable resonance signal in the presence of even minute fluctuations in hydrostatic pressure. In this work, we present a novel versatile planar sensor chip design (QCM chip) for a microliter-scale on-line biosensor. By sealing the quartz resonator along its edges to a flat, solid support, we provide uniform support for the crystal face not exposed to solvent, greatly decreasing deformation of the crystal resonator under hydrostatic pressure. Furthermore, this cassette design obviates the need for direct handling when exchanging the delicate quartz crystal in the flow cell. A prototype 27-MHz sensor signal exhibited very low noise over a range of flow rates up to 100 microL/min. In contrast, signals obtained from a conventional QCM sensor employing an O-ring-based holder were less stable and deteriorated even further with increasing flow rate. Additional control designs with intermediate amounts of unsupported undersurface yielded intermediate levels of stability, consistent with the interpretation that deformation of the crystal resonator under fluctuating hydraulic pressure is the chief source of noise. As a practical demonstration of the design's high effective sensitivity, we readily detected interaction between myoglobin and surface-bound antibody.     

CCL4 Regulates Eosinophil Activation in Eosinophilic Airway Inflammation

Eosinophilic chronic rhinosinusitis (ECRS) is a refractory airway disease accompanied by eosinophilic inflammation, the mechanisms of which are unknown. We recently found that CCL4/MIP-1β—a specific ligand for CCR5 receptors—was implicated in eosinophil recruitment into the inflammatory site and was substantially released from activated eosinophils. Moreover, it was found in nasal polyps from patients with ECRS, primarily in epithelial cells. In the present study, the role of epithelial cell-derived CCL4 in eosinophil activation was investigated. First, CCL4 expression in nasal polyps from patients with ECRS as well as its role of CCL4 in eosinophilic airway inflammation were investigated in an in vivo model. Furthermore, the role of CCL4 in CD69 expression—a marker of activated eosinophils—as well as the signaling pathways involved in CCL4-mediated eosinophil activation were investigated. Notably, CCL4 expression, but not CCL5, CCL11, or CCL26, was found to be significantly increased in nasal polyps from patients with ECRS associated with eosinophil infiltration as well as in BEAS-2B cells co-incubated with eosinophils. In an OVA-induced allergic mouse model, CCL4 increased eosinophil accumulation in the nasal mucosa and the bronchoalveolar lavage (BALF). Moreover, we found that CD69 expression was upregulated in CCL4-stimulated eosinophils; similarly, phosphorylation of several kinases, including platelet-derived growth factor receptor (PDGFR)β, SRC kinase family (Lck, Src, and Yes), and extracellular signal-regulated kinase (ERK), was upregulated. Further, CCR5, PDGFRβ, and/or Src kinase inhibition partially restored CCL4-induced CD69 upregulation. Thus, CCL4, which is derived from airway epithelial cells, plays a role in the accumulation and activation of eosinophils at inflammatory sites. These findings may provide a novel therapeutic target for eosinophilic airway inflammation, such as ECRS.