Harmonic analysis of a single-phase rectifier with a DC filter capacitor

A single-phase diode bridge rectifier with a filter capacitor on the dc side is often employed to convert ac input into a dc voltage. The input current of the rectifier contains harmonic currents which cause undesirable power line effects. Recently, a method using the time domain analysis has been proposed to calculate the harmonic currents of rectifier considering noninfinite capacitance, i.e., non-zero dc side impedance. This method is very accurate, but it requires a long computing time and a complicated algorithm. This paper proposes a new method that makes it possible to easily calculate the harmonic currents taking into account the effects of the ac and dc side impedances of rectifier. The proposed method, which is based on the frequency domain method, can be executed only with the algebraic computation, and its accuracy is quite high. The validity of the proposed method is also demonstrated by comparison with the results of time simulation.     

Scintillation from Eu2+ in Nanocrystallized Glass

A Eu²⁺-doped SiO₂–Al₂O₃–CaO–CaF₂ glass was prepared and converted into a transparent glass ceramic by heat treatment. The crystalline phase and its size were determined by X-ray diffraction and a transmission electron microscopy. The scintillation of Eu²⁺ ions in both glass and ceramic under X-ray excitation was investigated and compared with that in a single-crystal scintillator.     

Application of real-time PCR assays to genotyping of F-specific phages in river water and sediments in Japan

Genotyping of F-specific RNA phages is currently one of the most promising approaches to differentiate between human and animal fecal contamination in aquatic environments. In this study, a total of 18 river water and sediment samples were collected from the Tonegawa River basin, Japan, in order to describe the genogroup distribution of F-specific RNA and DNA phages using genogroup-specific real-time PCR assays. F-specific phages were detected in nine (100%) river water and six (67%) sediment samples. Eighty-five phage plaques were isolated from these samples and subjected to real-time PCR assays specific for the phages. F-specific RNA phages of human genogroups (II and III) were detected in 32 (38%) plaques, whereas those of animal genogroups (I and IV) were detected in 17 (20%) plaques. No correlation was observed between the genogroup distribution of F-specific RNA phages and the occurrence of human adenovirus genomes, suggesting that genotyping of the phages alone is inadequate for the evaluation of the occurrence of viruses in aquatic environments. SYBR Green-based real-time PCR assay revealed the presence of F-specific DNA phages in four (5%) plaques, which were further classified into two genogroups (fd- and f1-like phages) by sequence analysis. Thirty-two (38%) plaques were not classified as the F-specific phage genogroups, indicating the limited applicability of these real-time PCR assays to a wide range of aquatic environmental samples worldwide.     

SCR of NOx with NH3 over Cu/NaZSM-5 and Cu/HZSM-5 in the presence of decane

The selective catalytic reduction of NO_x with NH₃ in the presence of decane over Cu/ZSM-5 catalysts prepared from H⁺ and Na⁺ZSM-5 precursors were investigated. Cu/NaZSM-5 catalyst showed significantly higher NO_x conversion compared to Cu/HZSM-5. However, the presence of decane decreased the activity of both the catalysts, due to coke formation. Cu/HZSM-5 catalyst showed a larger decline in NO_x conversion with time on stream compared to Cu/NaZSM-5. The higher activity of Cu/NaZSM-5 is attributed, to the promoting effect of Na⁺ cations in the formation of active Cu⁺ and nitrite and nitrate intermediates species and retardation of coke formation.     

Dechlorination of chlorobenzene compounds on flyash; effects of metals, aqueous/organic solvents and temperatures

Dechlorination of chlorobenzene compounds on flyash by using a solution of calcium hydroxide and sulfur in aqueous/organic solvent at 60–170 °C, under oxygen deficient conditions was studied. High percentage of dechlorination was obtained under certain reaction conditions. The results suggested that at 90 °C, metals in general and copper and lead in particular enhanced the catalytic potential of flyash for dechlorination by hydrodechlorination and substitution reactions. But at high temperatures (120–170 °C), dechlorination process was adversely affected by these metals. The effects of water, organic solvents, temperatures and heating time, were studied and reactions conditions were optimized to get maximum dechlorination.     

Characterization of carbon nanofibers synthesized by microwave plasma-enhanced CVD at low-temperature in a CO/Ar/O2 system

The low-temperature synthesis of carbon nanofibers by microwave plasma-enhanced chemical vapor deposition using a CO/Ar/O₂ system and their characterizations were performed. At the optimum oxygen concentration of O₂/CO = 7/1000, vertically aligned CNFs can be synthesized at temperatures as low as 180 °C with growth rates of 4–6 nm/s. The diameter of bulk CNFs is about 50–100 nm and the surface of CNFs is covered by branching fibers and their nuclei with a diameter of about 5–20 nm. Not only the peaks originating from carbon chains, but also oxygen containing groups, such as CO and COC, are observed in the FTIR spectra. The CNFs growth rate is almost independent from the substrate temperature and it is concluded that an elementary process not on the substrates, but in the gas phase, is the rate-determining step in the present CO/Ar/O₂ microwave-plasma-enhanced CVD system.     

The Role of Autophagy in Chemical Proteasome Inhibition Model of Retinal Degeneration

We recently demonstrated that chemical proteasome inhibition induced inner retinal degeneration, supporting the pivotal roles of the ubiquitin–proteasome system in retinal structural integrity maintenance. In this study, using beclin1-heterozygous (Becn1-Het) mice with autophagic dysfunction, we tested our hypothesis that autophagy could be a compensatory retinal protective mechanism for proteasomal impairment. Despite the reduced number of autophagosome, the ocular tissue morphology and intraocular pressure were normal. Surprisingly, Becn1-Het mice experienced the same extent of retinal degeneration as was observed in wild-type mice, following an intravitreal injection of a chemical proteasome inhibitor. Similarly, these mice equally responded to other chemical insults, including endoplasmic reticulum stress inducer, N-methyl-D-aspartate, and lipopolysaccharide. Interestingly, in cultured neuroblastoma cells, we found that the mammalian target of rapamycin-independent autophagy activators, lithium chloride and rilmenidine, rescued these cells against proteasome inhibition-induced death. These results suggest that Becn1-mediated autophagy is not an effective intrinsic protective mechanism for retinal damage induced by insults, including impaired proteasomal activity; furthermore, autophagic activation beyond normal levels is required to alleviate the cytotoxic effect of proteasomal inhibition. Further studies are underway to delineate the precise roles of different forms of autophagy, and investigate the effects of their activation in rescuing retinal neurons under various pathological conditions.     

Residual stress evaluation in resin-molded IC chips using finite element analysis and piezoresistive gauges

The high residual stress in a resin-molded electronic package sometimes makes the electronic functions unstable. Therefore the residual stress in electronic packages, especially on the top surfaces of semiconductor chips, should be evaluated. The objective of this study is to present a simple method for evaluating residual stress in resin-molded semiconductor chips using a combination of experimental and numerical methods. The actual residual stress of the packaging process was measured by using test chips that included piezoresistive gauges. A linear thermoelastic finite element analysis was then carried out using a three-dimensional model. The finite element analysis was performed under a stress-free temperature determined by the temperature dependence of the residual stress, which was experimentally measured by using the piezoresistive test chips. The measured residual stress using the test chips agreed well with the results of the finite element analysis. It was therefore confirmed that the present evaluation method, combining experimental and numerical methods, is reliable and reasonable.     

JTE-607, an inflammatory cytokine synthesis inhibitor, attenuates ischemia/reperfusion-induced renal injury by reducing neutrophil activation in rats

Renal ischemia/reperfusion (I/R) injury is one of the main causes of postoperative renal failure. Activated neutrophils are implicated in the development of I/R-induced renal failure. JTE-607 has been reported to be a potent inhibitor of the multiple inflammatory cytokines in the endotoxic shock mouse model and heart Langendorff perfusion model. In this study, we examined whether JTE-607 attenuates I/R-induced renal injury by reducing neutrophil activation. Male wistar rats were intravenously administered JTE-607 (JTE group, 30 mg/kg) or 5% mannitol (control group) 30 min before ischemia. JTE-607 reduced the I/R-induced increases in the serum concentrations of blood urea nitrogen and creatinine, and improved the histopathologic changes, including acute tubular necrosis. I/R-induced an increase in neutrophil activation, reflected by increases in renal cytokine-induced neutrophil chemoattractant (CINC)-1 and myeloperoxidase (MPO) concentrations which were significantly reduced by JTE-607. These findings indicate that JTE-607 attenuates I/R-induced acute renal injury, probably by inhibiting neutrophil activation. JTE-607 might be a novel therapeutic strategy for the protection of postoperative renal failure in surgery associated with renal ischemia as well as renal transplantation.     

Restraint Method for Overcoming Heating Irregularity and Improving Heating Equipment Efficiency for Beverage Cans Using High‐Frequency Induction Heating

We were able to reduce heating irregularities in equipment for heating beverage cans by using the high‐frequency induction heating method and determining the resulting improvement in the heating efficiency. The heating irregularity between the top and bottom of the can was reduced to less than 3°C by improving the arrangement of the heating coils for the beverage can by thinning the winding and changing the circuit configuration. The efficiency of power conversion was improved from 93.0% to 97.4%. In this paper, the configuration of the equipment and the experimental results are reported.