Surface treatment of titanium dioxide nanopowder using rotary electrode dielectric barrier discharge reactor

Titanium dioxide (TiO2) nanopowder (P-25;Degussa AG) was treated using dielectric barrier discharge (DBD) in a rotary electrode DBD (RE-DBD) reactor.Its electrical and optical characteristics were investigated during RE-DBD generation.The treated TiO2 nanopowder properties and structures were analyzed using x-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR).After RE-DBD treatment,XRD measurements indicated that the anatase peak theta positions shifted from 25.3° to 25.1°,which can be attributed to the substitution of new functional groups in the TiO2 lattice.The FTIR results show that hydroxyl groups (OH) at 3400 cm-1 increased considerably.The mechanism used to modify the TiO2 nanopowder surface by air DBD treatment was confirmed from optical emission spectrum measurements.Reactive species,such as OH radical,ozone and atomic oxygen can play key roles in hydroxyl formation on the TiO2 nanopowder surface.     

Microbial Sensors for the Detection of Fish Freshness

A microbial sensor system consisting of immobilized living spoilage-causing bacterium, Alteromonas putrefaciens, and an oxygen electrode was prepared and applied to the continuous determination of fish freshness. Fish freshness was expressed as a ratio of A/B, where A is the current decrease of the microbial sensor obtained by the application of l0–50 μL fish extract and B is the current decrease by the equivalent volume of culture medium. Freshness of bluefin tuna and yellowtail meats stored in ice for up to 2 weeks was determined by both the proposed and the conventional K value enzyme sensor method. Good comparative results were obtained. One assay could be completed within 13 min.     

Comparison of 80-keV D+ Ion Implantation with Thermal D2 Doping in Silica by FTIR and ESR Spectroscopy

Behavior of deuterium atoms in fused silica, which were implanted by 80-keV D⁺ (D₂⁺, D₃⁺) ions or doped thermally by D₂ (or D₂O), was studied by infrared Fourier transform spectroscopy (FTIR) and by ESR spectroscopy. When 80-keV deuteron ions are implanted into fused silica, OD bonds are formed. The OD bonds are also formed by thermal doping with D₂ or D₂O. When the deuterated silica is γ-ray irradiated at 77 K, D atoms are formed by rupture of the OD bonds. The efficiency of the OD bond rupture in the deuteron-implanted silica is much less than that in the D₂-doped silica. It is concluded from the results of thermal annealing that the low efficiency of the OD bond rupture in the deuteron-implanted silica is due to the radiation damage accompanying the implantation process. However, the decay rate and detrapping energy of deuterium atoms, once formed in the silica, are similar in both cases.     

Decomposition of Mullite by Silica Volatilization

Thermal decomposition of mullite into corundum was investigated using a high-temperature X-ray single-crystal camera equipped with a gas-flame furnace and by scanning electron microscopy and electron probe microanalysis (EPMA). When heated to ∼1750°C, mullite decomposed to corundum by the liberation of the SiO₂ component with topotaxial relations of:

• (1) 

  (310)_mull∥(001)_cor; [001]_mull∥[110]_cor
• (2) 

  (130)_mull∥(001)_cor; [001]_mull∥[110]_cor
• (3) 

  (110)_mull∥(001)_cor; [001]_mull∥[110]_cor

Thus, it was considered that, when mullite decomposed into corundum, their oxygen close-packed planes were almost preserved. The SEM photographs showed that the crystals of the developed corundum are prismatic and ∼5 μm wide. The EPMA showed that the phase boundary between mullite and developed corundum is discontinuous.     

Application of a multiple-model adaptive filter method to inertial navigation systems

The multiple-model adaptive filter (MMAF) method is applied to the estimation of error states of inertial navigation systems (INS). Monte Carlo simulations are performed to evaluate the sensitivity of several MMAFs to uncertainties in flight condition, where a Doppler radar receiver or Omega receiver is considered as the reference information source. It is shown that the MMAF method is useful not only for a case where the actual system model is included within the candidate models, but also for a case where the actual system model is not included within the candidate models.     

Input-output linearization of nonlinear systems with time delays in state variables

The present paper is concerned with nonlinear systems that contain delays inside coupled with a part of state variables, which are often the cases in practical problems, but have not been treated yet. First we introduce an extension of the Lie derivative for a difference-differential equation; then we derive necessary and sufficient conditions for existence of a nonlinear feedback that linearizes the input-output behaviour of a system and decouples it from the delayed variables simultaneously. Discussions are given for two cases: firstly when the linearizing feedback contains only current values of state variables, and secondly when the linearizing feedback has memories to utilize the past values as well as the current values of state variables.     

OSAKA CITY'S EARTHQUAKE PREPAREDNESS IMPROVEMENT MEASURES

In the early morning of January 17, 1995, an earthquake of magnitude 7.2 occurred, with its epicenter in Awaji Island, to the south of Kobe City located near Osaka City. It was later named the Hanshin-Awaji Earthquake.

The earthquake left over 6,400 people dead and about 40,000 injured, completely destroying over 100,000 houses and buildings, causing about 300 fires, resulting in the suspension of such “lifelines” as city water, electricity, and gas supply, and halting transportation systems including road and railway traffic. It inflicted extensive damage not only on Kobe, but also on Osaka and other cities.

In the light of destruction caused by the earthquake, in 1997, the Osaka Municipal Government, the Osaka City Regional Preparedness Plan, which includes citizen evacuation in the event of earthquake, construction of seismic-resistant facilities, and fire-fighting and other emergency activities. The original plan was prepared, on the basis of an inter-plate earthquake occurring beneath the Pacific Ocean. In addition to this hypothesis, the new plan also incorporates the assumption that an earthquake with its epicenter under Osaka could occur due to movement of the Uemachi Faults running under the central part of the City in the north-south direction. Estimated damage that could be incurred through this potential earthquake were used for the latter plan.     

双束（H+/e-）辐照下氢对12Cr-ODS铁素体钢组织损伤影响研究

利用氢离子（H⁺）束和电子（e^-）束双束（H⁺/e^-）同时辐照用化学浸润法制备的新型12Cr-ODS铁素体钢，研究其辐照损伤效应及组织变化。实验结果表明：由于氧化物的钉扎，基体内保持低密度位错网络；辐照初期随辐照剂量的增加，缺陷团在位错线上及其周围形成，尺寸增加，密度不断增大，并形成间隙型位错环；不同温度下辐照均产生小尺寸高密度的空洞，随辐照剂量的增大，空洞长大速度降低，空洞密度缓慢减小；不同温度下，辐照剂量达15dpa时，空洞肿胀均小于0.15%。对辐照产生的点缺陷与氢相互作用进行理论分析，12Cr-ODS铁素体钢在623~823K经双束辐照后，表现出良好的抗辐照损伤性。     

Development of –1 MV DC Filter and High‐Voltage DC Measurement Systems for ITER NBI

This paper presents the development results of a ?1 MV dc filter and dc measurement systems for an ITER (International Thermonuclear Experimental Reactor) neutral beam injector (NBI) system. High accuracy of 0.5% and fast responsivity of 3.3 μs, ?3 dB are required for the dc measurement systems: both dc voltage dividers and DCCTs. Circuit design and thermal flow design were carried out to clarify and minimize their effects on the accuracy and responsivity. The validity of the established design was demonstrated by the actual‐product tests; temperature rise of each components fell below the allowable value; inner components of dc filter withstood dc ?1.2 MV; each voltage divider accurately measured the voltage during the dc ?1.2 MV withstand voltage test; the voltage dividers and the DCCTs were adequate to the requirements of responsivity (3.3 μs, ?3 dB).