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A novel approach in the fabrication of microarrays of dye and protein on fused silica plates using the laser-induced backside wet etching (LIBWE) technique is described. The surface of fused silica plates was initially precoated using trimethoxysilane self-assembled monolayers (SAMs) and then etched using the LIBWE method to obtain the desired microstructures on the plate surface. Using this technique, the SAMs on the nonirradiated areas were able to survive the LIBWE process and were used as templates for the subsequent deposition of dye molecules or proteins via chemical bonding or physical adsorption. In the case of fused silica plates precoated with fluorinated SAMs, the LIBWE method is used to remove the SAMs to expose the etched silica surfaces, on which a thin layer of pyranine molecules can be site-selectively deposited using an aqueous solution of pyranine. In another application, an ethanol solution of rhodamine 6G was preferentially deposited onto the nonirradiated areas. In yet another application, bovine serum albumin was preferentially deposited onto the laser-irradiated areas; in this case, the fused silica plates were precoated with poly(ethylene oxide) SAMs. Interestingly, when an aqueous suspension of polystyrene (PS) microbeads was cast onto the fused silica precoated with the fluorinated SAMs, hexagonally close-packed PS microbeads were deposited into the etched cavities. Depositions of the dye, protein, and microbeads were confirmed by visualization using a fluorescence microscope and scanning electron microscope.

The generation of 1- and 2-naphthynes by the photolyses of 1,2- and 2,3-naphthalenedicarboxylic anhydrides (1, 2), respectively, was investigated by means of Fourier transformed infrared (FT-IR) and ultraviolet−visible (UV−Vis) absorption spectroscopies and theoretical calculations. Consecutive decarboxylation and decarbonylation of 1 were quantitatively analyzed on the basis of UV−Vis absorption spectra. The quantum efficiencies of these processes were estimated as 2 × 10^-4 and 0.1, respectively. An isotopomer experiment showed that a cyclopropanone intermediate formed by the decarboxylation showed four C&dbd;O stretching bands due to anharmonic resonance. Benzocyclopentadienylideneketene was formed from 1-naphthyne and CO, whereas 2-naphthyne did not react with CO to form the corresponding ketene. This different behavior was discussed on the basis of the geometries and energies calculated at the B3LYP/6-31G** level. Moreover, it was shown that the UV−Vis absorption spectra of reactive intermediates generated in the argon matrix were described well by computations based on INDO/S and time-dependent density functional theory (TD-DFT) methods.

We investigated the laser ablation of an elastomer composite with picosecond‐ (ps‐) and femtosecond‐ (fs‐) pulsed UV lasers (ps‐laser: λ = 263 nm, τ = 8 ps; fs‐laser: λ = 248 nm, τ = 500 fs). Upon laser irradiation, a unique microstructure on the surface of the elastomer composite (acrylate polymer) containing carbon black (particle size: 18–30 nm) was observed. The laser‐ablated surfaces were analyzed by scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). The formation mechanism is discussed in terms of thermal effects induced by the different pulse durations of the lasers.

Orthonormal wavelet transformations are used to decompose velocity signals of grid turbulence into both space and scale. The transforms exhibit small-scale enhancements of (i) the spatial fluctuation, (ii) the correlation in space between the adjacent scales, and (iii) the correlation in space between the longitudinal and transverse components. The spatial fluctuation and the scale–scale correlation at small scales are more significant in the transverse component than in the longitudinal component. These features are the same for different families of wavelets. Turbulence contains tube-like structures of vorticity. We demonstrate that wavelet transforms of velocities are enhanced at the positions of the tubes, by using a direct numerical simulation. Thus our wavelet analyses have captured the effects of those coherent structures on velocities measured in the experiment, which would be difficult for traditional analysis techniques such as those with velocity increments.

Summary An observational study is conducted of the lee cyclogenesis that occurred on 11 December 1990 in the southeast region of the Japan central mountains (JCM). The area of the region, roughly defined by the 1000m above sea level is 250×250 km. The principal results are summarized as follows:i)The parent low, which triggered the lee cyclogenesis, was initiated by an upper-level vortex and accompanied by a low-level jet and surface cold front on the upstream side of the JCM. The system moved eastward along the northern edge of the JCM and dissipated.ii)The surface cold front approached the JCM, became blocked in the middle of the JCM, and stagnant for about three hours. South of the JCM, however, the cold front advanced eastward with no blocking. This resulted in the formation of a strong horizontal wind shear zone along the southeastern edge of the JCM, between the warmer air on the downstream side of the JCM and the colder air to the south. A shallow cyclonic vortex, confined to within 3 km above ground level was subsequently generated in the horizontal wind shear zone.iii)The vortex moved eastward along a meso-scale coastal warm front, which previously existed for more than ten hours over the Kanto Plain, since the morning of 11 December. The vortex coupled with the upper-level vortex when it moved over the warm sea area east of the Japanese Islands, and then rapidly developed (12hPa/12h).

Polymers with photolabile groups absorbing in the mid UV (around 300 nm) were irradiated with excimer-lasers (248 and 308 nm). Irradiation with 248 nm (KrF laser) corresponds to an excitation of the photostable phenyl system whereas the XeCl laser (308 nm) excites the labile triazeno groups (–NN–N). Thin polymer films (0.1–3 μm) were coated onto quartz or glass and irradiated below and above the threshold of ablation. The films were subsequently analyzed with various surface analysis techniques. Below the threshold of ablation the main feature at both irradiation wavelengths was the reduction of the absorption maximum at about 330 nm and an increase of the surface oxygen content (X-ray photoelectron spectroscopy) and therefore the surface polarity (contact angle). The surface remained smooth with no detectable micro-structures (scanning electron microscopy). Above the ablation threshold the absorbance at 330 nm decreased dramatically and the color of the film changed. For 248 nm irradiation the surface was darkened and a carbonization (XPS) with microstructures (SEM) was detected. The surface became non-polar in agreement with surface carbonization. In the case of 308 nm irradiation the surface remained smooth and no change of the chemical composition or surface polarity was detected, suggesting a photochemically induced layer by layer ablation process.

Standard spectroscopic and surface analysis techniques were used to study a triazeno polymer after laser treatment. Two different excimer lasers, KrF at 248 nm and XeCl at 308 nm, were applied as irradiation sources. For both excimer lasers fluences below and above the threshold of ablation were used. In the case of fluences below the threshold of ablation the irradiation led to a decrease of the absorption of the triazeno chromophore. From XPS spectrum and contact angle measurements a surface oxidation of the polymer is identified. After irradiation with fluences above the threshold of ablation for both irradiation wavelengths a different behavior is observed. Irradiation with the XeCl laser led to a less pronounced surface roughening as compared to KrF laser treatment. With the XPS and contact angle measurements, only slight changes could be detected. A totally different behavior was found for irradiation with the KrF excimer laser. The surface of the polymer turned black after the irradiation, and the oxygen and nitrogen content is drastically reduced, as determined from the XPS spectrum. The SEM pictures revealed the appearance of microstructures of about 5 μm size with some “treelike” structures at the top of the “naps”. Contact angle measurements show also the existence of a nonpolar surface. Spectroscopic techniques showed that there exists a clear difference between the irradiation of the triazeno polymer at the two wavelengths under ablation conditions. Excitation of the triazeno chromophore at 308 nm leads to clear ablation, whereas the irradiation with 248 nm introduces microstructures and a carbonized surface.

Laser ionization time-of-flight (TOF) mass spectrometry has been employed to probe the dynamics of ablation of polyethersulfone (PES) at 266 nm. Neutral products arriving at an ion extraction position, which was 65 mm from a PES film surface, were detected by delaying a post-ionization laser pulse with respect to an ablation laser pulse. At a low fluence of 30 mJ/cm², the strongest peak indicating early arrival of C3H3 (m/e = 39) was observed at post-ionization delay times of 12−22 μs. As the delay time increased (16−46 μs), some prominent peaks (m/e = 140, 164, 188, 216, 234, 262, 264, 280, 288, 312, 333, and 336) and many weak peaks with m/e up to about 690, which were assigned to direct fragments from PES or secondary products, were observed. Analysis of the products indicates that the decomposition of PES occurs due to both the scission of the polymer chain itself and the cleavage of some phenylene rings in the chain. The average flight velocities of major products ranged from 1.8 × 10⁵ cm/s for C15H12S2O5 (m/e = 336) to 4.1 × 10⁵ cm/s for C3H3. These products continued to arrive for a period of 6−15 μs, which was over 1200 times the ablation laser pulse length. The distribution, the velocities, and the yields of major products for several higher fluences up to 130 mJ/cm² suggest an enhanced decomposition of PES to small fragments in the upper part of a heated surface layer. The arrival profiles of C3H3 at various fluences were adequately described by a shifted Maxwell−Boltzmann distribution, indicating collisions among the fragments during an unsteady adiabatic expansion process. We propose a laser-penetration-depth dependent photothermal ablation model.

An accident occurred when an aircraft landed at Narita International Airport, Japan, on 20 June 2012. The aircraft encountered rapid changes of winds together with strong turbulence, although the weather was fair. In the present study, a two‐domain nested regional weather prediction models are used. The results in the outer domain show that southwesterly winds associated with a synoptic extratropical cyclone were locally accelerated to the southwest of the airport resulting in strong vertical shear. The simulation in the inner domain reproduces horizontal convective rolls, which are similar to those observed by a Doppler lidar at the airport. The wind velocity component parallel to the runway had a spatial variation of about 10 m s −1. The present approach using a large eddy simulation is useful for clarifying environments and features of horizontal convective rolls and forecasting low‐level wind shear associated with them, which can be a significant risk for aircraft. Synoptic/mesoscale fronts and downbursts (strong downdrafts from a thunderstorm and diverging winds after they hit the ground) are known to be serious threats to airplanes during takeoff and landing. However, it is less known that there is another type of danger under fair weather conditions. An aircraft landing at Narita International Airport, Japan, in the afternoon of 20 June 2012 encountered rapid changes of wind and turbulence and made a hard landing, resulting in several injuries and damage to the fuselage. A Doppler lidar, a remote sensing device for monitoring low‐level winds at the airport observed alternating regions of strong and weak winds aligned southwest–northeast, perpendicular to the runway. In order to clarify the detailed structure and mechanism of these disturbances, numerical simulations using a fine‐resolution (horizontal resolution: 100 m) nested in a coarse resolution (horizontal resolution: 1 km) are made. The simulations show that horizontal convective rolls, which occur in convective boundary layers with strong vertical shear (vertical gradient of horizontal wind speed) were prevailing. These rolls are associated with the rapid changes in wind speed and turbulence similar to those observed by the Doppler lidar and flight recorder. The present study demonstrates that the large eddy simulation is useful for clarifying the structure and mechanisms of horizontal convective rolls, which caused the aircraft accident, and also for forecasting them. Horizontal convective rolls that caused an aircraft accident in a fair weather condition were successfully reproduced by a numerical modelCharacteristics of the rolls and turbulence as observed by a Doppler lidar and flight recorder are clarified based on the model resultsCapability of accessing and operationally predicting potentially hazardous rolls by use of a large eddy simulation is demonstrated

Polydimethylsiloxane (PDMS) is fundamental materials in the field of biotechnology. Because of its biocompatibility, microfabricated PDMS sheets are applied to micro-reactors and microchips for cell culture. Conventionally, the microstructures were fabricated by means of cast or imprint using molds, however it is difficult to fabricate the structures at high aspect ratios such as through-holes/vertical channels. The fabrication of the high-aspect structures would enable us to stack sheets to realize 3D fluidic circuits. In order to achieve the micromachining, direct photo-ablation by short wavelength light is promising. In the previous works, we investigated ablation of transparent materials such as silica glass and poly(methyl methacrylate) induced by irradiation with laser plasma EUV light. We achieved smooth and fine nanomachining. In this work, we applied our technique to PDMS micromachining. We condensed the EUV light onto PDMS surfaces at high power density up to 108 W/cm2 using a Au coated ellipsoidal mirror. We found that PDMS sheet was ablated at a rate up to 440 nm/shot. It should be emphasized that through hole with a diameter of 1 m was fabricated in a PDMS sheet with a thickness of 4 m. Thus we demonstrated the micromachining of PDMS sheets using laser plasma EUV light.

Dehydrochlorination of 1,2‐dichloropropane (I) according to A) is found to be considerably accelerated compared to B).