• Title/Summary/Keyword: 저온조건

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Current Trend of Ultrahigh Vacuum Low Temperature Scanning Tunneling Microscopy (초고진공 저온 주사터널 현미경 장치의 최신 경향)

  • Ham, Ungdon;Yeom, Han Woong
    • Vacuum Magazine
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    • v.3 no.4
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    • pp.14-18
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    • 2016
  • In this article, we will summarize recent advances in ultrahigh vacuum (UHV) low-temperature scanning tunneling microscopy (STM) during the last decade. Leading STM groups have finished or are constructing UHV milli-Kelvin high magnetic field STM capable of a few tens of milli-Kelvin and ~ 10 tesla. Applications with UHV sub-Kelvin high magnetic STM have been increased since mid-2000's. Active research using UHV low temperature tuning fork atomic force microscopes and UHV photon low-temperature scanning tunneling microscopes will be introduced. Considering these advances of UHV low-temperature STM we will discuss next trend in STM in the near future.

LTCC and LTCC-M Technologies for Multichip Module (Multichip module 개발을 위한 LTCC 밀 LTCC-M 기술)

  • 박성대;강현규;박윤휘;문제도
    • Journal of the Microelectronics and Packaging Society
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    • v.6 no.3
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    • pp.25-35
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    • 1999
  • LTCC (Low Temperature Cofired Ceramic) or LTCC-M (Low Temperature Cofired ceramic on Metal) technology is one of MCM-C (Multichip Module on Ceramic) technologies and becomes to be widely used in consumer, RF and automotive electronics. As green sheets for LTCC are cofired below $1000^{\circ}C$ in comparison with those for HTCC (High Temperature Cofired Ceramic), high conductivity metal traces such as gold, silver and copper can be used. The dimensional stability in LTCC-M technology enables embedded passives to be integrated inside modules, which enhances the electrical performance and increases the reliability of the modules. Coefficient of thermal expansion and dielectric constant can be controlled by changing composition and heating profile for cofiring. In this technical review, LTCC and LTCC-M technologies are introduced and advantages of those technologies are explained.

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Effect of Storage Conditions on the Quality Stability of Garlic Bulbs (마늘의 품질안정성에 대한 저장조건의 영향)

  • 권중호;정형욱;이정은;박난영;이기동;김정숙
    • Food Science and Preservation
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    • v.6 no.2
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    • pp.137-142
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    • 1999
  • Physicochemical properties were evaluated for stored garlic bulbs during 9 months under different conditions, such as low-temperature condition (3${\pm}$1$^{\circ}C$, 80${\pm}$5% RH, LT), pit-temperature condition (9${\pm}$6$^{\circ}C$, 80${\pm}$5% RH,PT) and ambient-temperature condition (14${\pm}$11$^{\circ}C$, 67${\pm}$5% RH, AT). The internal sprout development was more significant in pit and ambient conditions than in low temperature and thus certain means for sprout control is required for long-term storage of garlic bulbs under such conditions. The rates of rotting and weight loss were appreciable especially after 7 months of storage (next March) in the order of PT, AT and LT, when external sprouts were observed in PT and AT. Moisture content of stored samples were relatively constant in LT until next May, but that in W and AT was significantly reduced after next January. Total sugars showed a decreasing tendency with the prolonged period, whereas an apparent increase was found in the contents of reducing sugar and vitamin C along with external sprouting of garlic bulbs from the 7th month of storage (next March). Based on the results that around March is a limiting point in garlic storage at such conditions from the physiological and physicochemical points of view, improved storage condition should be applied to overcome the storage barrier.

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Low-temperature growth of epi-Ge thin films by Reactive thermal CVD (반응성열CVD를 이용한 고효율 박막태양전지용 게르마늄박막의 저온에피성장)

  • Lim, Cheolhyun;Song, Sungheon;Lee, Sukho;Hanna, Junichi
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.102.1-102.1
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    • 2010
  • 고효율 멀티정션박막태양전지의 바텀셀 적용을 목적으로, 반응성CVD(Reactive thermal CVD)기술을 이용, $Si_2H_6+GeF_4$를 원료가스로, 이들이 가진 산화환원반응을 이용하여 400도 이하의 저온에서 Ge 및 Si 기판에 Ge을 에피성장 시켰다. Ge 기판위의 호모에피막의 경우, $2.5{\AA}/sec$의 성장속도와 99%의 Ge조성을 보였고, RHEED 및 HR-XRD를 통한 결정성 평가 결과, 고품질의 Ge 에피막의 성장이 확인되었다. 동일한 성장조건을 Si기판에 헤테로에피성장 시켰을 경우, 4% 격자불일치에 의해 막품질이 저하되는 것을 확인하였다. 이를 개선하기 위하여 저온에서 제작한 버퍼층에 대한 논의를 하고자 한다.

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Studies on the leaf discoloration caused by low temperature-Change of soluble protein components by temperature - (저온에 의한 수도의 Discoloration 발생에 관한 연구-온도에 의한 가용성단백질구성 변화에 관하여-)

  • Park, Kyeong-Bae;Tanaka, Takayuki;Harada, Jiro
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.23 no.1
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    • pp.1-4
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    • 1978
  • The change of soluble protein components in leaf discoloration of rice plant was investigated in the Growth Cabinet with various temperature conditions. The ratio between high molecular soluble protein and low molecular soluble protein was high under high temperature condition, while low under low temperature condition, and also lower in Indica type varieties than Japonica type variety.

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The Effect of Cold-adaptation on Stress Responses and Identification of a Cold Shock Gene, capA in Bradyrhizobium japonicum (Bradyrhizobium japonicum의 저온 전처리에 의한 환경스트레스 내성 증진에 대한 연구)

  • 유지철;노재상;오은택;소재성
    • Korean Journal of Microbiology
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    • v.38 no.1
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    • pp.45-49
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    • 2002
  • Bradyrhizobium japonicum is a soil bacterium with a unique ability to infect the roots of leguminous plants and establish a nitrogen-fixing symbiosis, which has been used as a microbial manure. In this study, we examined the stress response after pretreatment of cells with cold temperature. When pre-treated with cold temperature ($4^{\circ}C$) for 16 hr, B. japonicum increased the viability in subsequent stress-conditions such as alcohol, $H_2O_2$, heat, and dehydration. For cold adpatation, cultured B. japonicum was exposed to $4^{\circ}C$. Upon subsequent exposure to various conditions, the number of adapted cells pretreated by cold adaptation was 10-1000 fold higher than that of non-adaptated ones. It appeared de novo protein synthesis occurred during adaptation, because a protein synthesis inhibitor, chloramphenicol abolished the increased stress tolerance. By using a degenerate PCR primer set, a csp homolog was amplified from B. japonicum genome and sequenced. The deduced partial amino acid sequence of the putative Csp (Cold shock protein) shares a significant similarity with known Csp proteins of other bacteria.

Influence of Low Temperature Degradation on Bond Strength of Yttria-Stabilized Tetragonal Zirconia Polycrystal Core to Veneering Ceramic (저온열화현상이 지르코니아 코어와 전장도재의 전단결합강도에 미치는 영향)

  • Kim, Ki-Baek;Kim, Jae-Hong
    • Journal of dental hygiene science
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    • v.14 no.1
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    • pp.29-34
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    • 2014
  • The purpose of this study was to evaluate the influence of low temperature degradation (LTD) on the bonding strength of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP). The push-shear bond test method was used to investigate the core-veneer bonding strength of industrially manufactured Y-TZP core ceramic and manufacturer recommended veneering ceramic. Four groups from ceramic-zirconia specimens (n=28; n=7 per group) were assigned into four experimental aging conditions, namely storage in an autoclave at $134^{\circ}C$ for 0, 3, 5, 10 hours. Bonding strength was obtained using a universal testing machine with crosshead speed 0.5 mm/min. Data were statistically analyzed using one-way ANOVA and Tukey's test (${\alpha}=0.05$). In bonding strength test, the group which was treated with LTD showed lower bonding strength than no treated group. The ceramic-zirconia bonding strength was affected by LTD (p<0.05). Digital microscope examination of the fracture surface showed mixed failures with adhesive and cohesive types in LTD with treated Y-TZP groups.

Characteristics of Germination and Seedling Growth of Red Rice by Temperatures and Seeding Depths (앵미의 온도와 파종깊이 및 토양수분에 따른 발아와 유묘생육의 특성규명)

  • Cho, Young-Son
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.58 no.3
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    • pp.319-323
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    • 2013
  • Red rice (Oryza sativa L.) is one of the most important weeds in most of rice cultivating area. Seed germination related experiments were done to evaluate germination percentage, emerging speed, and initial growth by seeding depth and soil moisture level. The four experiments, 1) temperature, 2) seeding depth, 3) soil moisture level, and 4) seeding position, were done with combination each other on phytotron for germination and seedling growth related experiments of redrice. The treatments levels were: 1) Temperatures were 20/15(Low), 25/20 (Mid.), $30/25{\circ}C$ (High), (day/night), 2) seeding depths were 0, 3, 6 cm, 3) soil moisture levels were 25, 35, 45, 55, 65% (VWC, %), and seeding position were furrow, ridge, ridge-top. The germination percentage and germination speed of red rice were higher and faster than Daeanbyeo in low temperature. Yoeongcheon redrice of seed germination percentage and seedling length was more vigor than Hapcheon red rice. Red rice was not germinated on 6 cm seeding depth until 11 days after seeding except high temperature treatment. Germination percentage increased with increasing soil water percentage in low temperature, however it was greatest in 45% in high soil moisture level between 25% to 65% in low temperature. Seed germination percentage and seedling length were not significantly different among the soil water level in mid- and high temperature levels. In conclusion, red rice could germinate in top soil (<6 cm) in mid- and high temperature range, so we might be control red rice by spraying herbicide after germination of red rice combined with delayed rotary cultivation.