• 제목/요약/키워드: Electron life time

검색결과 185건 처리시간 0.024초

탄소나노튜브 방출원을 통한 초소형 질량분석기의 이온화 향상 (The Improvement of the Ionization on Micro Mass Spectrometer using Carbon Nanotube Emitter)

  • 송성호;한규성;;이순일;양상식
    • 전기학회논문지
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    • 제58권5호
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    • pp.1004-1009
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    • 2009
  • Recently, mass spectrometers are widely used for in-situ chemical analysis. It has rapid response and high sensitivity. In this paper, we present the fabrication and test of a cold cathode emitter for micro mass spectrometer using CNTs(Carbon nano tubes). The CNTs have good mechanical, electrical and chemical characteristics. So they have a long life time and strong robustness. The micro mass spectrometer is composed of the glass substrate and the silicon substrate. The glass substrate is constructed by electrodes for TOF(Time-of-flight) which analyze an ion with mass to charge ratio as ion separator. The silicon substrate is highly doped wafer which is patterned for gate electrode and then 100 11m dry etching to grow the CNTs as the electron emitter. The CNTs are grown by HFCVD(Hot filament chemical vapor deposition) with sputtering the catalyst. We successfully attained to grow the CNTs and to test the characteristics.

흑임자의 조리 조건에 따른 항산화 효과의 비교 (A Comparison of Antioxidant Activities in Black Sesame Seeds according to Preparation and Cooking Conditions)

  • 박정리;채경연;홍진숙
    • 동아시아식생활학회지
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    • 제17권4호
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    • pp.520-531
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    • 2007
  • In this study, we found that the moisture content of black sesame seeds increased in proportion to steaming time, and it decreased in reverse proportion to the roasting temperature and time. The crude fat and crude ash contents were shown to be in the order of steamed black sesame>raw black sesame and roasted black sesame>raw black sesame, Crude protein decreased in reverse proportion to the steaming time, and more crude protein was found in the raw black sesame samples than in the roasted black sesame samples. The contents of sesamin, sesamolin, and total lignans were shown to be in the order of roasted black sesame>raw black sesame>steamed black sesame. In the steamed black sesame samples, sesamin showed its highest level with 20 minutes of treatment, and sesamolin showed its highest level with 15 minutes of treatment. In the roasted black sesame samples, sesamin, sesamolin, and total lignans showed their highest levels with 15 minutes of treatment at $100^{\circ}C$. The phenolic compound content increased in proportion to steaming time in the steamed samples, and reached a peak after 15 minutes of treatment at $100^{\circ}C$, and then decreased after 20 minutes. SOD-like activity reached a peak after 15 minutes of treatment, and in the roasted sample it reached a peak after 15 minutes of treatment, and then decreased after 20 minutes. SOD-like activity was comparatively lower than tocopherol and higher than sesamol. The intensity of electron donating ability, following 30 minute treatments, was shown to be highest in the steamed black sesame samples after 25 minutes of treatment, and next highest in the roasted black sesame samples after 15 minutes at $100^{\circ}C$. The electron donating ability was comparatively lower than tocopherol and sesamol. With regard to lecithin's antioxidant effects, the steamed samples showed a higher oxidation restriction rate in proportion to time, and the roasted samples showed the highest rate after 15 minutes of treatment, and then decreased after 20 minutes of treatment. for hydroxyl radical scavenging, similar scavenging activity to tocopherol, and comparatively higher scavenging activity than sesamol, was shown in all samples: all samples showed scavenging abilities of 90% or higher. In summary, this study applied three different treatment methods to black sesame to determine the optimum treatment conditions, and also examined the antioxidant effects and functional characteristics. The results showed that roasting can be used for other purposes than producing oil, and also suggested that methods other than roasting can be used in a variety of ways in cooking. Also, the different treatment methods can be applied in cooking in a variety of ways, to enhance functionality and preference.

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STS 316鋼 의 高溫低사이클 疲勞强度 와 破壞擧動 에 미치는 크리이프 - 疲勞 相互作용 의 影響 (Effect of creep-fatigue interaction on high temperature low cycle fatigue strength and fracture behavior of STS 316 stainless steels)

  • 오세욱;이규용;김중완;문무경
    • 대한기계학회논문집
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    • 제9권2호
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    • pp.140-149
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    • 1985
  • 본 연구는 오오스테나이트계 STS 316 스테인레스강에 대하여 온도 550.deg. C의 대 기중에서, 변형율제어에 의한 인장-압축에 크리이프 유지시간을 갖는 고온저사이클 피 로시험을 하여 변형율폭 및 크리이프 유지시간이 피로수명에 미치는 영향과 파단면을 주사형 전자현미경으로 관찰하여 크리이프-피로 상호작용이 피로파단면에 미치는 크리 이프 효과를 실험 고찰하였다.

Saponin-SOD가 SNUC-4 Cell에 의해 유발편 대장암 Nude Mice의 암 성장 억제 효과 (Tumor-Suppressing Effects of Saponin-SOD in Nude Mice)

  • 박수진;강명화
    • 동아시아식생활학회지
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    • 제14권4호
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    • pp.338-342
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    • 2004
  • This study was performed to measure the antioxidant effects of red ginseng extracts which antioxidation had been promoted through enzyme hydrolysis. In order to observe their tumor-suppressing effects, an anti-cancer medicine and Saponin-SOD, which was a highly antioxidant beverage made from red ginseng saponin adding SOD-like rice (with embryo buds) extracts, were administered to nude mice with large intestine cancer induced. There was a significant increase in the content of phenolic compounds as the enzyme was added. The red ginseng extracts showed a high electron-donating ability with the passage of time. The electron-donating ability was particularly high in the enzyme-treated red ginseng extract, and also observed as high in Saponin-SOD. The lipid-peroxide generation was inhibited depending on the concentration of Saponin-SOD added; the addition of 0.625% Saponin-SOD served to decrease the inhibition level up to 65% compared with the case of no addition (100%). As a result, it could be assumed that Saponin-SOD would strongly inhibit the oxidation of ghost membrane. After the cancer was induced in nude mice through the injection of SNUC-4 cell, there was a significant inhibition in the growth of tumors in nude mice into which Saponin-SOD were injected; the growth of tumors was gradually decreasing with the passage of time after the cancer induction. In particular, when Saponin-SOD was administered together with an anti-cancer medicine, the synergic effect was observed. In conclusion, Saponin-SOD, when used with an anti-cancer medicine, is expected to reduce the amount of free radical and lipid peroxide, which are known to cause harmful effects occurring from the internal application of medicine.

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Electron Beam 조사에 의한 인삼분말의 살균효과 (Sterilizing Effect of Electron Beam on Ginseng Powders)

  • 이미경;이무하;권중호
    • 한국식품과학회지
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    • 제30권6호
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    • pp.1362-1366
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    • 1998
  • 전자가속기(electron accelerator)에서 발생되는 electron beam을 이용하여 인삼분말류에 대한 새로운 살균기법을 확보할 목적으로 시중에서 유통되고 있는 백삼 및 홍삼분말을 시료로 하여 그 살균효과를 감마선 조사법과 비교하였다. 백삼 및 홍삼 분말의 미생물 농도는 총세균이 $10^5\;CFU/g$ 수준이었고, 대장균군(coliforms)은 백삼분말에서는 시료 g당 $10^3\;CFU$ 수준으로 검출되었으나 홍삼분말에서는 음성으로 나타났다. Electron beam 조사에 따른 오염미생물의 살균효과는 호기성 총세균이 7.5 kGy, 곰팡이 및 대장균군이 2.5 kGy 이하의 조사선량으로써 미생물의 농도를 검출한계 이하로 살균시킬 수 있었고, 실온에서 4개월 간 저장후에도 미생물의 생육은 없었다. 초기 오염 총세균의 농도를 90% 사멸시키는데 필요한 조사선량($D_{10}$값), 즉 총세균의 방사선 감수성을 확인해 본 결과, 전자선은 $2.85{\sim}3.75\;kGy$, 감마선은 $2.33{\sim}2.44\;kGy$ 범위로 시료의 미생물 농도와 에너지의 종류에 따라 다소 다른 값을 나타내었으나 전자선은 감마선과 유사한 살균력을 나타내어 실용 가능성이 인정되었다.

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Clinical outcomes and prognostic factors in patients with mycosis fungoides who underwent radiation therapy in a single institution

  • Jang, Bum-Sup;Kim, Eunji;Kim, Il Han;Kang, Hyun-Cheol;Ye, Sung-Joon
    • Radiation Oncology Journal
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    • 제36권2호
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    • pp.153-162
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    • 2018
  • Purpose: We aimed to evaluate clinical outcomes including progression-free survival (PFS), overall survival (OS), partial response, and complete response in patients who underwent radiation therapy (RT) for mycosis fungoides (MF). Also, we sought to find prognostic factors for clinical outcomes. Materials and Methods: Total 19 patients confirmed with MF between 1999-2015 were retrospectively reviewed. Clinical and treatment characteristics, clinical outcomes, and and toxicities were analyzed. Results: Eleven patients were treated with total skin electron beam radiotherapy (TSEBT) and 8 patients with involved field radiation therapy (IFRT) with median dose of 30 Gy, respectively. The median time interval from diagnosis to RT was 2.6 months (range, 0.4 to 87.3 months). The overall response rate was 100%; 11 patients (57.9%) had a complete response and 8 patients (42.1%) a partial response. The presence of positive lymph node at the time of consultation of RT was associated with lower OS (p = 0.043). In multivariate analysis, PFS was significantly lower for patients with increased previous therapies experienced following RT (p = 0.019) and for patients showing PR during RT (p = 0.044). There were no reported grade 3 or more skin toxicities related with RT. Conclusion: Both IFRT and TSEBT are effective treatment for MF patients. Patients with short disease course before RT or complete response during RT are expected to have longer PFS. Positive lymph node status at the initiation of RT was associated woth poor OS, suggesting other treatment modalities such as low-dose RT for patients with low life-expectancy.

Characteristics of Fatigue Crack Initiation and Fatigue Strength of Nitrided 1 Cr- 1Mo-0.25V Turbine Rotor Steels

  • Suh, Chang-Min;Hwang, Byung-Won;Murakami, Ri-Ichi
    • Journal of Mechanical Science and Technology
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    • 제16권8호
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    • pp.1109-1116
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    • 2002
  • To investigate the effect of nitriding layer on both fatigue crack initiation and fatigue life, turbine rotor steel ( IC.- 1Mo-0.25V steel) specimens were nitrided by the nitemper method and then put to a rotary bending fatigue test at room and elevated temperatures. In nitriding, temperature and time were controlled to obtain a different nitrided thickness. Microstructure analysis, micro-Victors hardness test, and scanning electron microscope observation were carried out for evaluating experiments. In results, the fatigue cracks of nitrided specimens were initiated at inclusion near the interface between nitrided layer and substrate, which showed fish-eye type appearance in fractograph. The fatigue life of nitrided specimens at every temperature was prolonged compared to that of the non-nitrided. However, there was not observable improvement in fatigue characteristics with the increase of a nitrided thickness.

First Record and Morphological Features of the Dinoflagellate Peridinium aciculiferum Lemm. (Dinophyceae) in Korean Freshwater

  • Ki Jang-Seu;Han Myung-Soo
    • 환경생물
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    • 제23권4호
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    • pp.323-327
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    • 2005
  • Two morphologically different species of Peridinium were frequently observed in natural samples collected monthly from Togyo Reservoir. One was previously identified as P. bipes Stein f. occultatum (Lindem.) Lef. (Ki and Han 2005), the other was remained uncertainly so far. We resolved their identity, based on the morphological observations with scanning electron microscopy. The formula of epithecal plate was recorded with 7 precingular, 3 intercalary and 4 apical plates (4', 3a, 7'). An apical pore was apparently present. The conspicuous morphology of the Peridinium was three spines on the hypothecal plates. The average body length and width were $33.6\;{\mu}m$ with a range of $26\~45{\mu}m$, and 25.7 with a range of $19\~31{\mu}m$, respectively; the cell was, therefore, shown slightly elongated. Based on their morphological characteristics, the causative organism was identified as P. aciculiferum (Lemm.), which was reported for the first time in Korean freshwater.

Three New Records of Family Tubuliporidae (Bryozoa: Cyclostomata) from Korea

  • Chae, Hyun Sook;Min, Bum Sik;Yang, Ho Jin;Seo, Ji Eun
    • Animal Systematics, Evolution and Diversity
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    • 제38권1호
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    • pp.20-25
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    • 2022
  • This paper describes three cyclostomatous bryozoans belonging to the family Tubuliporidae Johnston, 1838 from Korean waters. It was carried out with the materials which were collected from three localities during the period from 2011 to 2017. As a result of the present study, three cyclostomatous bryozoans, Exidmonea intercalata Liu, Liu & Zágoršek, 2019, Qingdaoella conaria Liu, Liu & Zágoršek, 2019 and Tubulipora perforata Liu, Liu & Zágoršek, 2019 are newly added to the Korean bryozoan fauna. Furthermore, two genera, Exidmonea David, Mongereau & Pouyet, 1972 and Qingdaoella Liu, Liu & Zágoršek, 2019, are reported for the first time from Korea. These species were previously known only in Qingdao, China, which belongs to the temperate zone influenced by the Kuroshio Current. Descriptions and illustrations of the three cyclostomatous bryozoans using Scanning Electron Microscopy are provided in this study.

Three new records of Korean cyclostomatous bryozoans

  • yun Sook Chae;Ho Jin Yang;Bum Sik Min;Ji Eun Seo
    • Journal of Species Research
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    • 제12권4호
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    • pp.362-367
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    • 2023
  • Three cyclostomatous bryozoans from Korea belonging to the genera Bicrisia and Nevianipora are described here for the first time. The specimens collected from six localities of the South Sea and Jejudo Island during the period from 1981 to 2020 were observed. The three cyclostomatous bryozoans are Nevianipora pulcherrimoidea (Liu in Liu, Yin & Ma, 2001), N. rugatata (Liu in Liu, Yin & Ma, 2001), and Bicrisia edwardsiana (d'Orbigny, 1841). Nevianipora pulcherrimoidea and N. rugatata were previously found only from the South China Sea, whereas Bicrisia edwardsiana is widespread. As a result of this study, the Korean cyclostomatous bryozoans have increased to 20 species, 10 genera, and five families. Redescriptions and illustrations by scanning electron microscopy of the three species new to the Korean fauna are provided herein.