A review of the Japanese longline fishery for tunas and billfishes in the eastern Pacific Ocean, 1993-1997

English: This report reviews the Japanese longline fishery in the eastern Pacific Ocean during the 1993-1997 period, extending the studies for the 1956-1992 period made by other investigators. The spatial and temporal distributions of fishing effort, catch, apparent abundance, sexual maturity, and size composition are examined for the principal species of tunas and billfishes taken by that fishery. Some information on the catches of sharks by the Japanese longline fishery is given. The interactions between the surface and longline fisheries are discussed. Spanish: En este informe se presenta un análisis de la actividad pesquera de buques palangreros japoneses en el Océano Pacífico oriental durante el período de 1993-1997, extendiendo los estudios del período de 1956-1992 realizados por otros investigadores. Se examinan las distribuciones espacial y temporal del esfuerzo de pesca, la captura, la abundancia aparente, la madurez sexual, y la composición por talla de las principales especies de atunes y picudos capturadas por dicha pesquería. Se presenta cierta información sobre las capturas de tiburones por la pesquería palangrera japonesa. Se describen las interacciones entre las pesquerías de superficie y palangrera

Plasmon modes in single gold nanodiscs

Optical properties of single gold nanodiscs were studied by scanning near-field optical microscopy. Near-field transmission spectra of a single nanodisc exhibited multiple plasmon resonances in the visible to near-infrared region. Near-field transmission images observed at these resonance wavelengths show wavy spatial features depending on the wavelength of observation. To clarify physical pictures of the images, theoretical simulations based on spatial correlation between electromagnetic fundamental modes inside and outside of the disc were performed. Simulated images reproduced the observed spatial structures excited in the disc. Mode-analysis of the simulated images indicates that the spatial features observed in the transmission images originate mainly from a few fundamental plasmon modes of the disc

Leakage of Mildly Flammable Refrigerants into a Room

The use of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) has been widely restricted. They have been replaced with hydrofluorocarbons (HFCs) in order to protect the ozone layer. However, the leakage of refrigerant into air from active or end-of-life air conditioners has been a serious environmental issue owing to the high global warming potential (GWP). It has therefore been widely recognized that the replacement of HFCs with low-GWP refrigerants is a reasonable solution of the problem. In Japan, the low-GWP refrigerants such as R1234yf, R1234ze, and R32 are considered as candidate alternatives for conventional HFC refrigerants. However, these low-GWP refrigerants are often flammable. When refrigerants leak into a space, they tend to accumulate at the floor if they are heavier than air and ventilation is inadequate. If the refrigerant concentration is higher than the lower flammable limit (LFL), there is an ignition source, and the air velocity is lower than the burning velocity, the refrigerant may ignite. When leakage occurs from an air conditioner, there is always a region where the refrigerant concentration is higher than the LFL because the refrigerant concentration is about 100% near the outlet from the air conditioner. Thus, it is important to understand the diffusion phenomena of the low-GWP refrigerants when acquiring sufficient information for the safety standards to assess the risks in the usage of these refrigerants. Numerical analysis is an effective tool because it is very difficult to measure the diffusion of a refrigerant in a large space. In this study, diffusion phenomena were numerically analyzed when a refrigerant leaked from a room air conditioner (RAC), a package air conditioner (PAC) or a chiller into a large space where these were equipped. From the calculation results, the refrigerant concentration distributions, the volumes and positions of the flammable regions, and their changes in time were discussed