Flows in rectangular microchannels driven by capillary force and gravity

Capillary phenomena was studied and discussed by the scholars about 200 years ago, but the progress was slow due to the limited equipment and manufacture precision of the microchannel. In recent years, because of the rapid development of MEMS and micromachining, many applications of the capillary flow is widely developing in some modern processes, such as underfilling of flip chip, flow in microfluidic chip or biochip, and a variety of other fields.     

Effect of Cu concentration on the reactions between Sn-Ag-Cu solders and Ni

The reaction between the Sn-Ag-Cu solders and Ni at 250°C for 10 min and 25 h was studied. Nine different Sn-Ag-Cu solders, with the Ag concentration fixed at 3.9 wt.% and Cu concentrations varied between 0.0–3.0 wt.%, were used. When the reaction time was 10 min, the reactions strongly depended on the Cu concentration. At low-Cu concentrations (≦0.2 wt.%), only a continuous (Ni_1−xCu_x)₃Sn₄ layer formed at the interface. When the Cu concentration increased to 0.4 wt.%, a continuous (Ni_1−xCu_x)₃Sn₄ layer and a small amount of discontinuous (Cu_1−yNi_y)₆Sn₅ particles formed at the interface. When the Cu concentration increased to 0.5 wt.%, the amount of (Cu_1−yNi_y)₆Sn₅ increased and (Cu_1−yNi₆)₆Sn₅ became a continuous layer. Beneath this (Cu_1−yNi_y)₆Sn₅ layer was a very thin but continuous layer of (Ni_1−xCu_x)₃Sn₄. At higher Cu concentrations (0.6–3.0 wt.%), (Ni_1−xCu_x)₃Sn₄ disappeared, and only (Cu_1−yNi_y)₆Sn₅ was present. The reactions at 25 h also depended strongly on the Cu concentration, proving that the strong concentration dependence was not a transient phenomenon limited to a short reaction time. The findings of this study were rationalized using the Cu-Ni-Sn isotherm. This study shows that precise control over the Cu concentration in solders is needed to produce consistent results.     

A study on UV-curable coatings for HD-DVD: Primer and top coats

This study relates to the development of coatings for optical discs in high-density digital versatile disc systems (HD-DVD or blue lay disk) that use a high numerical aperture of 0.85 at 405 nm wavelength and have a protective top layer over a primer layer for protection against damage and dust. Ultraviolet-curable raw materials of two acrylic monofunctional monomers ( isobornylacrylate, IBA and tetrahydrofurfurylacrylate, THFA) and two kinds of urethaneacrylate oligomers (OUMD and OUME) have been easily mixed with photoinitiators. Curing rate of these materials was characterized by FT-IR. In case of top coats, VTES (vinyltriethoxysilane) and acrylic acid were added to enhance the abrasion resistance. These two kinds of UV-curable resinous materials having no solvent were synthesized and investigated as means for making a blue ray disk having good optical and mechanical properties. In addition, dynamic characteristics including reflectivity, fluctuation of RF signal and noise level were also investigated.     

Describing metal surfaces and nanostructures with orbital-free density functional theory

Orbital-free density functional theory (OF-DFT) can be made to scale linearly with sample size, allowing thousands of atoms to be treated explicitly with quantum mechanics. State-of-the-art kinetic energy density functionals and ion–electron pseudopotentials are used to obtain accurate structural property predictions for nanoparticles, nanowires, extended surfaces, and nanoindentation of simple metals.     

Bibliometric analysis of tsunami research

The use of the bibilometric analytical technique for examining tsunami research does not exist in the literature. The objective of the study was to perform a bibliometric analysis of all tsunami-related publications in the Science Citation Index (SCI). Analyzed parameters included document type, language of publication, publication output, authorship, publication patterns, distribution of subject category, distribution of author keywords, country of publication, most-frequently cited article, and document distribution after the Indonesia tsunami. The US and Japan produced 53% of the total output where the seven major industrial countries accounted for the majority of the total production. English was the dominant language, comprising 95% of articles. A simulation model was applied to describe the relationship between the number of authors and the number of articles, the number of journals and the number of articles, and the percentage of total articles and the number of times a certain keyword was used. Moreover the tsunami publication patterns in the first 8 months after the Indonesia tsunami occurred on 26 December 2004 indicated a high percentage of non-article publications and more documents being published in journals with higher impact factors.     

An Area Optimization Method for Digital Filter Design

In this paper, we propose an efficient design method for area optimization in a digital filter. The conventional methods to reduce the number of adders in a filter have the problem of a long critical path delay caused by the deep logic depth of the filter due to adder sharing. Furthermore, there is such a disadvantage that they use the transposed direct form (TDF) filter which needs more registers than those of the direct form (DF) filter. In this paper, we present a hybrid structure of a TDF and DF based on the flattened coefficients method so that it can reduce the number of flip‐flops and full‐adders without additional critical path delay. We also propose a resource sharing method and sharing‐pattern searching algorithm to reduce the number of adders without deepening the logic depth. Simulation results show that the proposed structure can save the number of adders and registers by 22 and 26%, respectively, compared to the best one used in the past.     

Renal R2 chemoreceptor activity is attenuated after back heating in the rat

The aim of the present study was to determine the afferent connections of the nucleus accumbens in snakes, in particular its catecholaminergic input. For that purpose, in vitro and in vivo applications of retrograde tracers in the nucleus accumbens of Elaphe guttata were combined with tyrosine hydroxylase (TH) immunohistochemistry. Both techniques revealed telencephalic inputs to the nucleus accumbens originating from the diagonal band of Broca, ventral pallidum, amygdaloid complex, and dorsal cortex. Major diencephalic inputs arise from the dorsomedial thalamic nucleus and the hypothalamus. In the brainstem, a few retrogradely labeled cells were observed in the raphe nucleus and the locus coeruleus. Considerably more cells were found in the midbrain tegmentum. Within the confines of the locus coeruleus and, in particular, the midbrain tegmentum, retrogradely labeled cells stained also for TH suggesting that those areas constitute the major catecholaminergic input to the nucleus accumbens of snakes. The experimental approach used in the present study, in particular the in vitro technique, seems to be very suited for studying the development of basal ganglia organization of reptiles in the near future.     

Nickel- and copper-coated carbon fibre reinforced tin-lead alloy composites

Nickel and copper were deposited over brominated, surface treated, and pristine P-100 carbon fibres using cementation and electroplating techniques. The fibres were brominated by bromine vapour for 48 h and then desorbed at 200 °C in air for 12 h. The anodic oxidation treatment of the fibres involved electrochemical etching in a dilute sodium hydroxide electrolyte for 3 min. Electroplated coated fibres showed better tensile properties than cementation coated fibres. In addition, nickel coating exhibited better bonding with the carbon fibres compared to copper coating. The effect of bromination and surface treatment was improved adhesion between coating and fibres. Nickel- and copper-coated fibres, which were brominated, anodically oxidized, and pristine, reinforced tin-lead alloy composites were fabricated by squeeze casting. The composites containing coated treated carbon fibres had higher tensile and shear strength than the ones containing coated pristine carbon fibres. Moreover, the composite with coated brominated carbon fibres had better tensile strength and shear strength than the surface treatment. The results also showed the composites containing nickel-coated fibres had higher tensile and shear strength than the ones containing copper-coated fibres.