• 제목/요약/키워드: snag

검색결과 144건 처리시간 0.028초

굴 패각을 사용한 경량기포 콘크리트의 단위시멘트량에 따른 물리적 성능에 관한 연구 (Study on physical performance of lightweight foam concrete using oyster shells according to unit cement content)

  • 홍상훈;신종현;신동욱;김봉주;정의인
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2020년도 봄 학술논문 발표대회
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    • pp.102-103
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    • 2020
  • Research for heat insulation of buildings is being carried out, in which a heat exchange barrier is used around the openings and balcony parts as a method for heat exchange blocks. However, the preparation for a fire is inadequate. In order to improve the EPS used as a heat exchange barrier in an attempt to solve this, there is a study on lightweight foamed concrete, but as the amount of EPS used for strengthening fire resistance increases, it becomes lower. There is no strength applied to buildings, and also. There is a limit to the amount of EPS used. In the study, we use oyster shells to secure the EPS replacement rate limit of lightweight Foamed concrete, and try to measure the change of physical properties depending on the unit cement content.

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동작 상상 EEG 분류를 위한 이중 filter-기반의 채널 선택 (A Dual Filter-based Channel Selection for Classification of Motor Imagery EEG)

  • 이다빛;이희재;박상훈;이상국
    • 정보과학회 논문지
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    • 제44권9호
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    • pp.887-892
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    • 2017
  • 뇌-컴퓨터 인터페이스는 정신 작업 동안 다채널에서 생성된 뇌파의 신호를 측정, 분석하여 컴퓨터를 제어하거나 의사를 전달하는 기술이다. 이때 최적의 뇌파 채널 선택은 뇌-컴퓨터 인터페이스의 편의성과 속도뿐만 아니라 정확도 향상을 위해 필요하다. 최적의 채널은 중복 채널들 또는 노이즈 채널들을 제거함으로써 얻는다. 이 논문에서는 최적 뇌파 채널을 선택하기 위해 이중 filter-기반의 채널 선택 방법을 제안한다. 제안한 방법은 먼저 채널들 간의 중복성을 제거하기 위해 spearman's rank correlation을 사용하여 중복 채널들을 제거한다. 그 뒤, F score를 이용하여 채널과 클래스 라벨 간의 적합성을 측정하여 상위 m개의 채널들만을 선택한다. 제안한 방법은 클래스 라벨과 관련되고 중복이 없는 채널들을 사용함으로써 좋은 분류 정확도를 이끌어 낼 수 있다. 제안한 채널 선택 방법은 채널의 수를 상당히 줄임과 동시에 평균 분류 정확도를 향상시켰다.

가지 흰가루병의 발생 (Occurrence of Powdery Mildew on Eggplant in Korea)

  • 이상엽;황순진;이상범
    • 식물병연구
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    • 제8권3호
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    • pp.171-174
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    • 2002
  • 2000년 가을에 경기도 여주의 가지재배하우스포장에서 흰가루병이 발생하여 병원균의 형태 등을 조사하였다. 병징은 잎의 앞면, 뒷면과 잎자루에서 흰가루의 균총이 형성되어서 진전됨에 따라서 잎이 황화되어 말라서 결국 낙엽이 되었다. 이 병원균의 분생포자는 분생자경의 끝에 연쇄적으로 생기며 , 무색, 단세포, 타원형내지 장타원형으로 피브로신체를 가지고 있으며, 그 크기는 25~40$\times$15~22 $\mu\textrm{m}$ 이었다 분생포자의 발아관은 단순발아관이며,부착기는 뚜렷하지 않았고,분생자경은 거의 수직으로 분지하였고, 기부는 대부분 직선상이었으며, 그 길이는 47~100 $\mu\textrm{m}$ 이었다. 기부세포는 길이가 15-81 $\mu\textrm{m}$(평균 44$\mu\textrm{m}$), 폭이 10~16 $\mu\textrm{m}$ (평균 13 $\mu\textrm{m}$)이었다 그리고 분생자경상의 연쇄상 미성숙 분생포자들이 곡상외선(crenate edge)을 가지고있었다. 이상의 결과로부터 Sphaerotheca fusca에 의한 가지흰가루병으로 동정되어 국내에서 처음으로 보고한다.

경사진 임플란트 고정체의 응력 분석 (Stress analysis on the implant fixture with the angulated placement)

  • 김창현;강재석;부수붕;오상호;안옥주;강동완
    • 구강회복응용과학지
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    • 제20권2호
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    • pp.71-81
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    • 2004
  • The purpose of this study was to compare the distributing pattern of stress on the finite element models of two units implant prosthesis with one angulated placement of two implant fixtures. The two unit implant crowns simulated to mandibular first and second molars were made. The two kinds of finite element models were designed according to angulation of fixture ($4.0mm{\times}11.5mm$) : Model 1($15^{\circ}$ buccally angulated placement of one fixture on second molar area), Model 2($15^{\circ}$ lingually angulated placement of one fixture on second molar area). Axial loads of 200N were applied to the center of central fossa and to distance of 2mm and 4mm apart from the center of central fossa. Von-Mises stresses were recorded and compared in the fixtures, and buccolingual section of implants. The results were as follows: 1. Under axial loading at the central fossa, the stress was distributed along the straight fixture except apical portion, while on buccally or lingually angulated placement, the highest stresses were concentrated in the neck portion on the opposite side of the angulated fixture. 2. With offset distance increasing, the stresses were concentrated greater in buccal neck of lingually angulated fixture than in lingual neck of buccally angulated fixture. From the above results, in designing of the occlusal scheme for implant prosthesis with the angulated fixture, occlusal contacts should be placed to distribute stress axially in maximum intercuspation and to avoid offset force during eccentric movements.

Purification and Characterization of Arylphorin of the Chinese Oak Silkmoth, Antheraea pernyi

  • Park, Snag-Bong;Kim, Jeong-Wha;Kim, Soohyun;Park, Nam-Sook;Jin, Byung-Rae;Hwang, Jae-Sam;Seong, Su-Il;Lee, Bong-Hee;Park, Eunju
    • International Journal of Industrial Entomology and Biomaterials
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    • 제6권1호
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    • pp.33-44
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    • 2003
  • The arylphorin was purified from the pupal haemolymph of the Chinese oak silkmoth, Antheraea pernyi, and characterized physiologically and biochemically, The protein was purified by a simple preparative polyacrylamide gel electrophoresis (PAGE) and subsequent diffusive elution. The preparation was shown to be homogeneous by 7.5% native-PAGE. The native molecular weight of arylphorin was 450 kDa with a 80 kDa single subunit, suggesting hexamer, The protein contained high amounts (18.3%) of aromatic amino acids, phenylalanine (9.7%) and tyrosine (8.6%). Therefore, the protein was identified as a kind of a storage protein referred to as an arylphorin. The protein was stained by Schiff's reagent, suggesting a glycoprotein. The protein contained 4.9% (w/w) sugar and mannose and N-acetylglucosamine were major components. Also, degradation of the protein was begun by heat treatment at 90 for 20 minutes. These results showed that the A. pernyi arylphorin in the study is hexamer associated with the six subunits consisting of a 80kDa single subunit, and is different from that of Kajiura et al. (1998) in the subunit composition.

Micromachinng and Fabrication of Thin Filmes for MEMS-infrarad Detectors

  • Hoang, Geun-Chang;Yom, Snag-Seop;Park, Heung-Woo;Park, Yun-Kwon;Ju, Byeong-Kwon;Oh, Young-Jei;Lee, Jong-Hoon;Moonkyo Chung;Suh, Sang-Hee
    • The Korean Journal of Ceramics
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    • 제7권1호
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    • pp.36-40
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    • 2001
  • In order to fabricate uncooled IR sensors for pyroelectric applications, multilayered thin films of Pt/PbTiO$_3$/Pt/Ti/Si$_3$N$_4$/SiO$_2$/Si and thermally isolating membrane structures of square-shaped/cantilevers-shaped microstructures were prepared. Cavity was also fabricated via direct silicon wafer bonding and etching technique. Metallic Pt layer was deposited by ion beam sputtering while PbTiO$_3$ thin films were prepared by sol-gel technique. Micromachining technology was used to fabricate microstructured-membrane detectors. In order to avoid a difficulty of etching active layers, silicon-nitride membrane structure was fabricated through the direct bonding and etching of the silicon wafer. Although multilayered thin film deposition and device fabrications were processed independently, these could b integrated to make IR micro-sensor devices.

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Seasonal Comparison of Voluntary Intake and Feeding Behaviour in Korean Spotted Deer (Cervus nippon)

  • Moon, S.H.;Jeon, B.T.;Lee, S.M.;Kim, K.H.;Hudson, R.J.
    • Asian-Australasian Journal of Animal Sciences
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    • 제13권10호
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    • pp.1394-1398
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    • 2000
  • This experiment was carried out to examine the seasonal changes in feed intake and feeding behavior in Korean spotted deer under farmed condition to obtain basic information for efficient feeding management. The seasonal daily gain was the highest (p<0.05) in summer and the lowest (p<0.05) in winter. Dry matter intake (DMI) was the highest (p<0.05) in spring (2,685 g/day) and the lowest in winter (1,929 g/day). Intake of roughage in the DMI was the greatest in spring and that in winter was significantly lower (p<0.05) than in spring. Also DMI, expressed in terms of metabolic body weight ($kgW^{0.75}$), was 85.5 g, 70.6 g, 70.9 g and 65.1 g for spring, summer, autumn and winter, respectively, and thus was the highest in spring and the lowest in winter (p<0.05). Deer exhibited similar eating patterns, comparatively short and frequent periods, in all seasons. They showed comparatively intensive patterns of rumination during midnight for autumn and winter and relatively continuous patterns of chewing activity during spring and summer. There were no significant differences in seasonal eating time and ruminating time. However, exercise time was the greatest for winter and the lowest for summer and there was a significant difference (p<0.05) between summer and winter. Although not significant, eating time per 100 gDM ingested tended to be short in spring and summer and long in autumn and winter. Ruminating time per 100 gDM ingested was the shortest (p<0.05) in spring compared with in other seasons. The conclusion can be drawn that since deer have seasonal differences in feed intake and feeding habits, it is necessary to establish and develop an efficient feeding system for deer.

Isolation of Streptomyces sp. KK565 as a Producer of ${\beta}-Amyloid$ Aggregation Inhibitor

  • Hwang, Sung-Eun;Im, Hyung-Min;Kim, Dong-Hoon;Shin, Hyun-Ju;Shin, Dong-Hoon;Park, Jeong-Eun;Jo, In-Ho;Kim, Chang-Jin;Yoo, Jong-Shin;Kang, Jong-Min;Lim, Dong-Yeon;Ahn-Jo, Snag-Mee;Kwon, Ho-Jeong
    • Journal of Microbiology and Biotechnology
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    • 제13권5호
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    • pp.809-814
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    • 2003
  • ${\beta}-amyloid$ ($A{\beta}$) peptides from the proteolytic processing of ${\beta}-amyloid$ precursor protein (${\beta}-APP$) aggregates in the brain to form senile plaques, and their aggregation plays a key role in pathogenesis of Alzheimer's disease (AD). To isolate an active compound that has an $A{\beta}$ aggregation-inhibitory activity, 2,000 microbial metabolite libraries were screened based on their ability to inhibit $A{\beta}$ aggregation by using both Congo red and thioflavin T assays. As a result, a water-soluble fraction of a soil microorganism, KK565, showed a potent $A{\beta}$ aggregation-inhibitory activity. The strain was identified as Streptomyces species, based on the cultural and morphological characteristics, the presence of diaminopimelic acid in the cell wall, and the sugar patterns for the whole-cell extract. In addition, the purification of active principle resulted in identifying a heat-unstable protein responsible for the $A{\beta}$ aggregation-inhibitory activity.

지능형 무선 인지 기술 기반 네트워크 환경에서 MAC 계층 동적 주파수 선택 방법 (Dynamic Frequency Selection Method for Medium Access Control in Cognitive Radio Networks)

  • 조경진;김현주;노권문;유상조
    • 한국통신학회논문지
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    • 제31권7B호
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    • pp.632-641
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    • 2006
  • 최근 FCC에서는 허가된 무선 통신 시스템의 비어 있는 주파수에 대해 허가되지 않은 통신 시스템의 중복 사용에 대한 내용을 고려하고 있다. 하지만 허가된 시스템과 비허가 시스템의 공존으로 인해 기존의 허가된 무선 통신 사용자에게 유해한 간섭을 주어 심각한 통신 성능 저하를 초래할 우려가 있다. 이와 관련하여 본 논문에서는 우선 인지 기술(cognitive radio technology)을 기반으로 MAC(Medium Access Control) 계층에서의 동적 주파수 선택 방법에 대하여 제안한다. 동적 주파수 선택 방법은 기지국과 단말의 센싱을 통해 획득한 감지 정보를 바탕으로 비어 있는 주파수 대역을 검출하여 채널 리스트를 생성하고 허가된 무선 통신 시스템을 감지하면 능동적으로 사용 가능한 채널로 이동을 수행하는 방법으로, 이는 기존의 허가된 무선 통신 시스템에 간섭으로써 영향을 줄일 수 있는 동시에 비허가 시스템과 허가된 시스템의 공존을 가능하게 함으로써 채널의 효율성을 극대화시킬 수 있다.

Cathodic Electrochemical Deposition of Highly Ordered Mesoporous Manganese Oxide for Supercapacitor Electrodes via Surfactant Templating

  • Lim, Dongwook;Park, Taesoon;Choi, Yeji;Oh, Euntaek;Shim, Snag Eun;Baeck, Sung-Hyeon
    • Journal of Electrochemical Science and Technology
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    • 제11권2호
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    • pp.148-154
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    • 2020
  • Highly ordered mesoporous manganese oxide films were electrodeposited onto indium tin oxide coated (ITO) glass using sodium dodecyl sulfate (SDS) and ethylene glycol (EG) which were used as a templating agent and stabilizer for the formation of micelle, respectively. The manganese oxide films synthesized with surfactant templating exhibited a highly mesoporous structure with a long-range order, which was confirmed by SAXRD and TEM analysis. The unique porous structure offers a more favorable diffusion pathway for electrolyte transportation and excellent ionic conductivity. Among the synthesized samples, Mn2O3-SDS+EG exhibited the best electrochemical performance for a supercapacitor in the wide range of scan rate, which was attributed to the well-developed mesoporous structure. The Mn2O3 prepared with SDS and EG displayed an outstanding capacitance of 72.04 F g-1, which outperform non-porous Mn2O3 (32.13 F g-1) at a scan rate of 10 mV s-1.