Electro-optic switch constructed with a poled silica-basedwaveguide on a Si substrate

2×2 electro-optic switching is demonstrated in an integrated Mach-Zehnder interferometer constructed with thermally poled GeO₂ -doped silica-based channel waveguides on a Si substrate     

Simulation study on refractometry by the rainbow method

To realize a high-precision refractive-index measurement by the rainbow method by use of multifringes, the characteristics of several orders of supernumerary bow fringes are made clear by a simulation based on the Huygens-Fresnel principle. The fringe intervals computed are precisely coincident with those obtained in experiments. As a result a suitable combination of the diameter of the cylinder containing the sample and the beam size of the laser has been determined. By use of the characteristic curve of the deviation angle versus the refractive index for each fringe and by the statistical treatment, measurement with high precision was demonstrated.     

Resin micromachining by roller hot embossing

The roller hot embossing is an efficient process of manufacture in which patterns are continuously transcribed on film, etc. Recently, the application of the embossing roll to the manufacturing processes of micro parts is paid attention. In this paper, we examined the development of the embossing roll with patterns of micron level and we tried to make the embossing roll mold by using the LIGA process. In this study, instead of producing embossing patterns directly on the roll surface, we fabricated a flexible thin mold with micro-patterns, which was then wrapped onto a cylinder to form an embossing roll, and tested the soft-mold roller hot embossing method. First, by optimizing UV exposure conditions of UV lithography, we prepared a resist pattern of numerous dots with a diameter of 10 μm, a sag height of 8 μm and a pitch of 20 μm. By Ni-electroforming this pattern, a 50 μm-thick thin mold was successfully fabricated. The 50 μm-thick mold was then wrapped onto a cylinder to form an embossing roll. In the roller hot embossing process, the 10 μm-diameter dot shape was successfully replicated on PET sheets.     

A Flexible electronic‐paper display with an ultra‐thin and flexible LSI driver using quick‐response liquid‐powder technology

Abstract— A thin and flexible LSI driver with a thickness of less than 35 μm for a passive‐matrix‐driven Quick‐Response Liquid‐Powder Display (QR‐LPD?) was successfully mounted onto the flexible printed circuit (FPC) and the back substrates of a flexible QR‐LPD?. Amounted LSI driver on a plastic substrate shows no significant degradation in the driving performances and maintains physical flexibility without any connection failures. This technology can realize a fully flexible electronic paper in combination with a plastic‐substrate QR‐LPD? fabricated by a roll‐to‐roll process.     

Robotic surgery setup simulation with the integration of inverse-kinematics computation and medical imaging

At present, there are representative robot operation systems such as da Vinci and ZEUS which have realized minimally invasive surgery by the use of dexterous manipulators. In the operating room, medical staff must prepare and set up an environment in which the robot has optimal freedom of motion and its functions can be fully demonstrated for every case. The range of motion in which the robot can reach and be maneuvered is restricted by the fixed point of the trocar site. We have developed a preoperative planning system with the function of volume rendering of medical images and automatic positioning by applying an inverse-kinematics computation of surgical robot. The motion of a surgical robot can be simulated in advance with the intuitive interface and kinematics computation program running in the background of the system. If robotic surgery planning with volume rendering of DICOM images is possible, the discussion of a surgical plan can be directly made just after the diagnosis considering the patient-specific structure. This kind of setup platform would be essential for the future introduction of surgical robotics into an operating room.     

Defluorination-enhanced hydrogen adsorptivity of activated carbon fibers

Fluorinated activated carbon fibers (F-ACFs) were prepared by direct thermal fluorination of pristine activated carbon fibers. By the pyrolysis of F-ACFs at 1073 K under nitrogen gas flow, fluorine was subsequently eliminated and the sp²-bonded ACF structures were recovered. The micropore widths were 1.1 and 0.8 nm, and the isosteric heats of adsorption of nitrogen were 11.3 and 12.8 kJ/mol for pristine and defluorinated ACFs, respectively. These results strongly suggest that changes occurred in the structural properties of micropores in defluorinated ACFs. The hydrogen adsorption isotherms showed that the defluorinated ACFs adsorbed more hydrogen gas than pristine ACFs at 77 K, suggesting that the potential for interaction between hydrogen molecules and the defluorinated slit nanospaces was increased due to the changes in the pore structural properties and/or to the induced polarization of the pore walls making up the modified π-electron systems.     

Structure and reactivity of MoO3-MgO catalysts

Surface of OH groups on reduced MoO₂-MgO catalysts such as $$ - - Mg - - O - - \begin{array}{*{20}c} {||} \\ {Mo} \\ | \\ \end{array} - - OH$$ may act as an active site for hydrogenation of propene. The surface hexa-coordinated Mo⁵⁺ ion (MO _6c ⁵⁺ ) was reduced to a lower number of cation such as Mo⁴⁺ or Mo³⁺ which act as an active site for metathesis of propene.     

Partial oxidation of methane using a microscale non-equilibrium plasma reactor

A flow-type, microscale, non-equilibrium plasma reactor was developed for partial oxidation of methane without a catalyst. A wide range of oxygen and methane mixtures was directly processed without dilution or explosion at ambient temperature because the microscale plasma reactor removes excess heat generated by partial oxidation, thereby maintaining a reaction field at temperatures near room temperature. Consequently, the least reactive methane was excited by high-energy electrons, whereas successive destruction of reactive oxygenates was minimized simultaneously within the extremely confined environment. A highly reactive and quenching environment is thereby obtained within a single reactor: these are paradoxical conditions in conventional thermochemical processes. A major product among liquid oxygenates was methanol, whose selectivity reached 34% at 30% of methane conversion. Selectivity of oxygenates such as methanol and formaldehyde depends strongly on the fragmentation pattern of methane dissociation by electron impact. Maximum selectivity of oxygenates, which is estimated from numerical simulation of a filamentary microdischarge, reaches 60% when the applied electric field corresponds to the breakdown field of methane (80 Td, 1 Td = 10⁻¹⁷ V cm²). The discharge current increases markedly with an applied electric field, but the selectivity of oxygenates decreases as the field strength increases.     

Densification of Lead Selenide and Lead Sulfide by Hot Isostatic Pressing

PbSe and PbS are both volatile and difficult to densify by normal sintering. We tried to sinter these compounds in a closed system, that is, by hot isostatic pressing in a glass capsule. Hot isostatic pressing was carried out for these compounds on the basis of their thermal behaviors in air as studied by TG-DTA. The maximum bulk densities obtained were 8.10 and 7.50 g/cm³, respectively, corresponding to their theoretical densities. The microstructures of the isostatically hot-pressed bodies were also observed by SEM. The present work shows that ceramic compounds which are normally volatile can be densified by encapsulation in glass followed by hot isostatic pressing.     

Dependence of selective reduction of NO with C3H6 on acid properties of ion-exchanged zeolites

The effect of amount and strength of acid sites on the activity and selectivity for the selective reduction of NO with C₃H₆ in the presence of excess oxygen over H-form and ion-exchanged zeolites has been investigated. The activity was found to be proportional to the acid amount determined by NH₃-temperature programmed desorption, but independent of the acid strength of the zeolites. The selectivity, i.e., the ratio of the reduction of NO with C₃H₆ to the oxidation of C₃H₆ by O₂, was independent of the amount and strength of acid sites.