638 research outputs found

    Frontal positions and mixed layer evolution in the Seasonal Ice Zone along 140°E in 2001/02

    Get PDF
    We describe the circulation and seasonal development of the upper ocean in the Seasonal Ice Zone (SIZ) of the Southern Ocean along 140°E. The 140°E section was repeated four times between November 2001 and March 2002, spanning the period from early spring to autumn. The sea ice edge was located at 62°-63°S in November, and retreated to 65°S in January. The circulation in the region is dominated by several fronts: the southern branch of Polar Front (PF-S) was located between 60° and 61.5°S; the northern branch of Southern ACC front (sACCf-N) was located at 61.5°-63°S, and roughly corresponds with the winter sea ice edge; and the southern branch of sACCf, the southern boundary of the ACC, and the Antarctic Slope Front (ASF) were closely spaced and found between 64°S and 65°S. Vigorous cyclonic (clockwise) eddies were identified in the region between the sACCf-N and sACCf-S throughout the period. Changes in salinity made the dominant contribution to changes in density in the SIZ, while changes in temperature made the largest contribution to density changes in the AZ, north of the sACCf. The depth of the mixed layer generally shoaled to the south, in all seasons. The decrease in mixed layer depth occurred in a series of steps. Seasonal variability in the depth of the mixed layer was strongest in the AZ, where summer warming formed a strong seasonal thermocline above the relatively deep (100 m) Winter Water layer. In the SIZ, the mixed layer became warmer, fresher and lighter in summer but the depth of the mixed layer remained at about 50 m throughout the year. The freshest surface waters were observed in the SIZ in January, immediately following the melt and retreat of the sea ice pack. An increase in mixed layer salinity from January to March likely reflects the effect of mixing with saltier waters below the mixed layer. Mixed layer depths south of the ASF were highly variable, both within and between seasons, varying from a minimum of ~20 m in January to over 500 m in March

    Long-term and seasonal changes of the mean sea level at Syowa Station, Antarctica, from 1981 to 2000

    Get PDF
    Sea level has been observed since 1966 at Syowa Station, a Japanese Antarctic station located on East Ongul Island(39.6°E , 69.0°S ). An almost continuous record has been obtained from 1981 to 2000 and analyzed to investigate long-term and seasonal changes of mean sea level. After correction of year-to-year variation of the datum, it is found that the annual mean sea level has been falling at a rate of 1.2cm/year. This rate is bigger than previous estimations calculated from shorter records of sea level without appropriate datum adjustment, and also bigger than that expected from geological evidence. Based on discussion of the reasons for the trend, it is suggested that glacial rebound can not be excluded as the cause. The present analysis based on a long record for about 20years also provides the amplitude(2.7cm) and phase of the nodal tide with the period of 18.6years. Characteristics of the seasonal change for the first half of the record(1981-1989) are different from those for the second half(1990-2000), associated with replacement of the observing system in 1990. Comparing with seasonal changes at other Antarctic stations and considering the results of previous studies, it is concluded that the seasonal change observed in the second half is more reliable, and that it reaches its maximum in April and minimum in October with an estimated annual tidal range of about 14cm

    A ZigBee/Wi-Fi Cooperative Channel Control Method and Its Prototyping

    Get PDF
    Coexistence between ZigBee and Wi-Fi technologies, which operate within the same frequency band, is increasing with the widespread use of the IoT (Internet of Things). ZigBee devices suffer significant decrease in the sink arrival rate of packets in the presence of Wi-Fi interference. To overcome this problem, many channel control methods have been proposed. These existing methods switch only ZigBee channels to avoid interference with Wi-Fi. In contrast, we propose a cooperative channel control method for improving ZigBee packet arrival rate by controlling both the Wi-Fi and ZigBee channels. Specifically, the proposed method not only controls ZigBee devices and channels but also requests a temporary pause in the use of specific Wi-Fi channels. Finally, we show the effectiveness of the proposed method from the viewpoints of ZigBee’s packet arrival rate and applications’ satisfaction using computer simulations. In addition, the effective action of the proposed method is also demonstrated by experiments with prototyping

    環状O-ペプチドの合成研究

    Get PDF
    金沢大学理学部研究課題/領域番号:X00210----874152, 研究期間(年度)1973出典:研究課題「環状O-ペプチドの合成研究 」課題番号 X00210----874152(KAKEN:科学研究費助成事業データベース(国立情報学研究所)) (https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-X00210----874152/)を加工して作

    有機イオウ化合物を活性種とする新しい合成反応の開発と天然物合成への応用

    Get PDF
    金沢大学理学部研究課題/領域番号60540325, 研究期間(年度):1985出典:研究課題「有機イオウ化合物を活性種とする新しい合成反応の開発と天然物合成への応用」課題番号60540325(KAKEN:科学研究費助成事業データベース(国立情報学研究所)) (https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-60540325/)を加工して作

    A Route to Indoles via Modified Fischer Indole Intermediates from Sulfonanilides and Ketene Dithioacetal Monoxides

    Get PDF
    An S−N variant of the N−N‐based Fischer indole synthesis has been developed. Treatment of sulfonanilides and ketene dithioacetal monoxides with a powerful acid anhydride provides N‐sulfonyl‐2‐methylsulfanylindoles. The initial interrupted Pummerer reaction would yield the key S−N‐tethered precursor in situ that then undergoes [3, 3] sigmatropic rearrangement, after which the endgame to the indole ring follows the Fischer manner

    有機硫黄化合物を用いる新しい有機合成反応の開発と天然物合成への応用

    Get PDF
    金沢大学理学部1.多置換ピロール類の新規構成法の開発とポルフィリン化合物への変換i)入手容易なα-シアノビニル型スルホンを出発物質とし、1、3-ジオキソランの光照射により3-シアノ-3-メシルプロパナール=エチレン=アセタールを調製し、αー位のアルキル化、シアノ基の還元、アミノ基をメシル化した後、酸処理することによりN-メシル-3、4-二置換ピロール誘導体を効率よく合成することができた。ii)N-(2-メチルチオ-1-P-トルエンスルホニルエチル)メタンスルホンアミドと3-トシルプロパナール=エチレン=アセタール誘導体との塩基性条件下による反応により得られる付加生成物を単離することなく酸処理すると、それぞれ対応する2-メチルチオメチル-3、4-二置換ピロール誘導体に導くことができた。iii)ii)で得られた生成物をスルホキシド誘導体に酸化したのち、メタノール性2M-KOHと処理すると定量的に2-メトキシメチル-3、4-二置換ピロールに変換され、メタノールーギ酸中反応させると対応するポルフィリノーゲンに環化し、更にジクロロメタン中酸素雰囲気下酸化することにより、極めて高収率でポルフィリン化合物に導くことができた。2.パラジウム(II)触媒を用いる合成反応2-(P-トルエンスルホニル)-3-ブテノールや2-メタンスルホニル-4-ペンテニルアミン誘導体に対し、Pdcl_2を作用させると円滑に分子内環化反応が進行し、それぞれ対応するフランやピロール誘導体が好収率で得られることを見い出した。3.ビニル型スルホンの異性化反応における立体化学塩基性条件下、(E)-ビニル型スルホンからは(Z)-アリル型スルホンへ、(Z)-ビニル型スルホンからは(E)-アリル型スルホンへ優先して異性化反応が進行するという極めて興味ある事実を見い出した。研究課題/領域番号:63540390, 研究期間(年度):1988出典:研究課題「有機硫黄化合物を用いる新しい有機合成反応の開発と天然物合成への応用」課題番号63540390(KAKEN:科学研究費助成事業データベース(国立情報学研究所)) (https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-63540390/)を加工して作

    A Case of Acquired Leucoderma, Associated with Hashimoto's Thyroiditis

    Get PDF
    A 67-year-old female diagnosed as Hashimoto's thyroiditis in company with acquired leucoderma was reported. She first noticed the enlarged thyroid at the age of 36, and thereafter leucoderma made its appearance 30 years later. Though a significant association between these two diseases has been found in the literature thus far and they are considered to be of autoimmune origin, their coexistence is not so common clinically. In spite of PUVA treatment, a benefit effect was not obtained completely

    The Kuroshio Region off Southwest Japan ASUKA 1993-95 Inverted Echo Sounder Data Report

    Get PDF
    In order to study the time-varying volume and heat transports of the Kuroshio off southwest Japan, a large number of scientists from Japan and a small number from the U.S.A. formed a group called ASUKA. This group carried out a coordinated investigation which was concentrated in time on the years 1993-95, and in space on a 1,000 km segment of a TOPEX/POSEIDON suborbital track running south-southeast from western Shikoku. This report describes the techniques used to process data collected by ten inverted echo sounders (IES) on this 1,000 km line off Japan, as part of the ASUKA study. The University of Rhode Island (URI) was responsible for all the IES\u27s except IES5 and IES8 which were from the Hydrographic Department of the Japanese Maritime Safety Agency (MSA/HD). The URI IES\u27s were deployed from the Training Vessel Keiten-maru in October 1993 and recovered from the same vessel in November 1995. The MSA/HD IES\u27s were deployed from the Survey Vessel Shoyo in July 1993. IES8 was recovered by Shoyo in May 1994, but unfortunately IES5 was not recovered
    corecore