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形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2021-06-03, 資料番号: PA2210003000

We investigated the seasonal occurrence and vertical distribution/migration of larval and juvenile northern smoothtongue,Leuroglossus schmidti(Pisces, Bathylagidae), in oceanic areas of the western subarctic Pacific. This species was the most abundant larval fish and one of the most abundant juvenile/adult fish at the study site. Larval recruitment of this species occurred in early March to mid-October. Larvae were found, however, throughout all seasons, suggesting that some had overwintered. The highest abundance (5.8 individuals m–2) of larvae was in summer. During summer and autumn, hatching mainly occurred at 100–150-m depth and larvae migrated toward the surface with growth. Once larvae reached about 20 mm in length, they moved below 100 m, and larger larvae (over 24 mm) exhibited diel vertical migration. The abundance of juveniles integrated through the water column was relatively constant (0.3 individuals m–2) throughout the study period. They were collected from below 300 m during the day, and part of the population (13–38%) swam into the epipelagic layer at night. The information on early stages ofL. schmidtipresented here provides a basis for future investigations of mesopelagic fish ecology in oceanic areas of the western subarctic North Pacific Ocean.

Accepted: 2019-04-04, 資料番号: SA1190018000

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2018-01-10, 資料番号: PA1810001000

Simulations of magnetic particles are mostly carried out under spatially and temporally static magnetic fields. It is well known that chain-like clusters are formed under these constant fields. However the hysteresis characteristics of particles are therefore often neglected. In this paper, methods to analyze behavior of magnetic particles with hysteresis characteristics under fluctuating fields are proposed. Consideration of hysteresis characteristics and fluctuating fields brings nonlinearity and driving forces to the system in addition to the energy dissipation caused by particle collisions. This research aims to find the foothold of chaotic behavior, which is often found in these systems, among particle clustering. The proposed methods start from the discretization of fields. Collisions and clustering are modeled by treating mechanical contacts, namely, by solving Hertz's contact problem. A symplectic integrator is used for time integration. For the simulation, behavior of 200 magnetic particles under spatially and temporally fluctuating fields were examined. The results imply hysteresis characteristics have a great effect on clustering patterns.

This paper describes a pixel size shrinkage of an amplified MOS image sensor (AMI). We have developed a new circuit technique to achieve the reduction of a pixel size while realizing vertical two-line mixing and high sensitivity. A 1/4-in format 250-k pixel image sensor was developed using a 0.8-/spl mu/m CMOS process. The difference from the conventional CMOS process is an additional layer of ion-implantation process. The power supply voltages of this imager are 4 and 6 V. The dynamic range of 75 dB, the sensitivity of 1.8 /spl mu/A/Ix, and the smear noise of less than -120 dB have been attained for the pixel size of 7.2 (H)/spl times/5.6 (V) /spl mu/m/sup 2/. Although the measured fixed pattern noise ratio (FPN) of this imager is -55 dB, analysis with a test chip shows that FPN can be improved by 2 dB by adopting a suitable gate length for amplifier and resetting MOSFET, respectively.