Microfluidic devices, which consist of networks of channels with micrometer dimensions, have attracted considerable attention in a wide range of applications including analytical systems, biomedical devices, and as tools for chemistry and biochemistry based experiments 1 5 . These devices can produce monodisperse droplets with exceptional precision, which are useful as individual compartments for chemical reactions and templates for preparation of monodisperse functional particles 6 11 . To date, several types of microfluidic devices have been developed. For example, capillary microfluidic devices consist of coaxial assemblies of tapered glass capillaries on glass slides 12,13 .Although the device can be fabricated at low cost, it is cumbersome to set the positions and sizes of the capillaries precisely. There are also polydimethylsiloxane PDMS devices, which consist of patterned microchannels in a silicone elastomer of PDMS fabricated by soft lithography techniques 14 16 . Although using soft lithography facilitates accurate control of the positions and sizes of the channels in the device through the design of mask patterns, it is difficult to fabricate flow channels in three dimensions, which would limit the utility of the device for many applications. 21 , could be prepared by polymerization of a gelation reagent dissolved in the monodisperse water droplets. Although stereolithography is a promising method for fabricating three-dimensional microfluidic devices, the default properties of the resin are inappropriate for many applications. For example, the device cannot produce oilin-water O/W emulsions and double emulsions, consisting of drops of oil and water assembled into a core-shell structure, owing to the hydrophobic surface properties of the flow channels 22,23 . To broaden the applicability of the devices, control of the wetting characteristics of the surface of channels is necessary. In this paper, we report on the surface treatment of the NOTE Abstract: A microfluidic device with three-dimensional flow channels was fabricated by stereolithography, and hydrophilic surface treatment of the flow channel was performed by coating the wall of the channel with a silica layer. After the treatment, the device produced monodisperse oil-in-water (O/W) emulsions. The silica layer on the channel surface was then coated with a fluorinated silane coupling agent to make it hydrophobic, thus enabling the treated device to produce monodisperse inverted water-in-oil (W/O) emulsions.

The thermosensitivity of gel-immobilized colloidal photonic crystals can be controlled by changing the mixing ratio of thermosensitive N-isopropylacrylamide (NIPAM) and non-thermosensitive N-methylolacrylamide (NMAM) in the gel network. Above an NMAM mole fraction of 0.4, the crystals exhibit linear thermosensitivity, a characteristic that makes them potentially useful in applications such as tunable photonic crystals and temperature sensors.

An orthotropic steel deck is quite susceptible to fatigue cracking at its welded joints depending on the structural stiffness, occurrence of high-magnitude cyclic load stress, and complicated geometric details of the welded joints. This study experimentally and numerically investigated the structural behavior of an orthotropic steel deck with bulb ribs. The behavior of the deck was examined, particularly the warped deformations of the developed fatigue cracks and the uniform stress distributions against moving loads attributed to the deck's asymmetric bulb ribs. An artificial fatigue crack serving as an authentic model of a fatigue crack was developed in the longitudinal bulb rib of an orthotropic steel deck in actual service. The loading tests were conducted on an orthotropic steel deck with artificial fatigue cracks. The test results were evaluated based on the artificial fatigue crack length on the longitudinal bulb ribs and compared with a nonlinear full finite-element analysis model considering the nonlinear contact behavior of artificial fatigue cracks.

In recent years, regional ground rebound phenomenon caused by the rising of groundwater level has been observed in an urban area in Japan such as Tokyo. This phenomenon might affect the underground structures constructed in those areas. In this study a centrifuge model test was carried out to investigate the fundamental mechanism of tunnel deformation and ground rebound during water rising process. In the centrifuge model test, two model tunnels were installed in different depths of clay ground in order to investigate the influence of ground depth on tunnel deformation. It is found that the relationship between ground surface displacement and elapsed time obtained from centrifuge model test shows similar tendency to the field measurement data. It is confirmed that deformation patterns of the two tunnels were different in the water rising process. This is considered to be due to the difference in deformation and pore water pressure in different layers of clay ground. Detail discussions on deformation mechanism of the two tunnels and pore water pressure distribution in clay are presented in this paper.

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