Effects of additive gases and plasma post-treatment on electrical properties and optical transmittance of ZnO thin films

A zinc oxide (ZnO) thin film as a channel layer in an oxide thin film transistor (TFT) has been characterized by investigating the effects of additive gases (such as hydrogen and oxygen) during growth and plasma treatment (using argon or hydrogen) after growth on its electrical, optical, and structural properties. By decreasing the additive gas ratio of O₂/H₂ or by increasing the treatment time of hydrogen plasma, the electrical resistivities of ZnO films were significantly reduced, and their transmittances and optical bandgap energies were blue-shifted in wavelength. These results were considered to be closely related to the passivation of oxygen vacancies as well as the formation of shallow donors that were induced by the injection of hydrogen in ZnO via gas addition and plasma treatment. In addition, the injection of hydrogen-including additive gas resulted in a decrease in grain size and crystallinity of ZnO films, whereas the plasma treatment hardly affected their crystalline structures.     

Using Numerical Analysis to Develop and Evaluate the Method of High Temperature Sous‐Vide to Soften Carrot Texture in Different‐Sized Packages

The high‐temperature sous‐vide (HTSV) method was developed to prepare carrots with a soft texture at the appropriate degree of pasteurization. The effect of heating conditions, such as temperature and time, was investigated on various package sizes. Heating temperatures of 70, 80, and 90 °C and heating times of 10 and 20 min were used to evaluate the HTSV method. A 3‐dimensional conduction model and numerical simulations were used to estimate the temperature distribution and the rate of heat transfer to samples with various geometries. Four different‐sized packages were prepared by stacking carrot sticks of identical size (9.6 × 9.6 × 90 mm) in a row. The sizes of the packages used were as follows: (1) 9.6 × 86.4 × 90, (2) 19.2 × 163.2 × 90, (3) 28.8 × 86.4 × 90, and (4) 38.4 × 86.4 × 90 mm. Although only a moderate change in color (L*, a*, and b*) was observed following HTSV cooking, there was a significant decrease in carrot hardness. The geometry of the package and the heating conditions significantly influenced the degree of pasteurization and the final texture of the carrots. Numerical simulations successfully described the effect of geometry on samples at different heating conditions.     

High space harmonic perturbations in travelling wave tubes

Stability properties of the free streaming mode in an electron beam propagating through a cylindrical waveguide loaded with a tape helix are investigated, including influence of high space harmonic perturbations. Closed algebraic dispersion relation of the free streaming mode are obtained. Properties of the high space harmonic perturbations are numerically investigated in connection with application on a high frequency microwave amplifier. One of the most important features in this analysis is that instability of high harmonic perturbations occurs at a very large value of microwave frequency. In this regard, millimeter microwave can be easily attainable by reducing the helix radius to a subcentimeter.     

Highly effective anode structure in a direct formic acid fuel cell

We report the mass transport characteristics of formic acid and performance enhancement in a direct formic acid fuel cell in terms of the property of anode components. The effect of hydrophobicity of anode diffusion media as well as catalyst layer was investigated applying different cell temperature and fuel concentration. The operation over 80 °C and concentrated formic acid is of great advantage to the enhancement of catalytic activity and better water management. On the other hand, the conductivity of formic acid decreases by means of the formation of more complex chains of formic acid and the fuel cell resistance increases by membrane dehydration effect due to the hygroscopic property of formic acid, resulting in overall decrease of cell performance and long-term stability. Optimizing operating conditions, the use of 60% PtRu/C with only 1 mg/cm² on plain carbon paper can be one of the good choice to achieve both sustainable power performance and higher utilization of anode catalysts keeping cell resistance.     

Low‐temperature oxidation of methane to form formaldehyde: role of Fe and Mo on Fe–Mo/SiO2 catalysts, and their synergistic effects

The partial oxidation of methane with molecular oxygen was performed on Fe–Mo/SiO₂ catalysts. Iron was loaded on the Mo/SiO₂ catalyst by chemical vapor deposition of Fe₃(CO)₁₂. The catalyst showed good low‐temperature activities at 723–823 K. Formaldehyde was a major condensable liquid product on the prepared catalyst. There were synergistic effects between iron and molybdenum in Fe–Mo/SiO₂ catalysts for the production of formaldehyde from the methane partial oxidation. The activation energy of Mo/SiO₂ decreased with the addition of iron and approached that of the Fe/SiO₂. The concentration of isolated molybdenum species (the peak at 1148 K in TPR experiments) decreased as the ion concentration increased and had a linear relationship with the selectivity of methane to formaldehyde. The role of Fe and Mo in the Fe–Mo/SiO₂ catalyst was proposed: Fe is the center for the C–H activation to generate reaction intermediates, and Mo is the one for the transformation of intermediates into formaldehyde. Those phenomena were predominant below 775 K. This revised version was published online in July 2006 with corrections to the Cover Date.     

Jmjd3 Mediates Neuropathic Pain by Inducing Macrophage Infiltration and Activation in Lumbar Spinal Stenosis Animal Model

Lumbar spinal stenosis (LSS) is a major cause of chronic neuropathic back and/or leg pain. Recently, we demonstrated that a significant number of macrophages infiltrated into the cauda equina after compression injury, causing neuroinflammation, and consequently mediating neuropathic pain development and/or maintenance. However, the molecular mechanisms underlying macrophage infiltration and activation have not been elucidated. Here, we demonstrated the critical role of histone H3K27 demethylase Jmjd3 in blood-nerve barrier dysfunction following macrophage infiltration and activation in LSS rats. The LSS rat model was induced by cauda equina compression using a silicone block within the epidural spaces of the L5-L6 vertebrae with neuropathic pain developing 4 weeks after compression. We found that Jmjd3 was induced in the blood vessels and infiltrated macrophages in a rat model of neuropathic pain. The blood-nerve barrier permeability in the cauda equina was increased after compression and significantly attenuated by the Jmjd3 demethylase inhibitor, GSK-J4. GSK-J4 also inhibited the expression and activation of MMP-2 and MMP-9 and significantly alleviated the loss of tight junction proteins and macrophage infiltration. Furthermore, the activation of a macrophage cell line, RAW 264.7, by LPS was significantly alleviated by GSK-J4. Finally, GSK-J4 and a potential Jmjd3 inhibitor, gallic acid, significantly inhibited mechanical allodynia in LSS rats. Thus, our findings suggest that Jmjd3 mediates neuropathic pain development and maintenance by inducing macrophage infiltration and activation after cauda equina compression and thus may serve as a potential therapeutic target for LSS-induced neuropathic pain.