• 제목/요약/키워드: $^{16}N$

검색결과 8,500건 처리시간 0.037초

V형 양자선 레이저의 전류 차단층에 대한 연구 (A Study on Current Blocking Configuration of V-Groove Quantum Wire Laser)

  • 조태호;김태근
    • 한국전기전자재료학회논문지
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    • 제16권12S호
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    • pp.1268-1272
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    • 2003
  • In order to enhance current Injection efficiency of Y-groove inner strife(VIS) quantum wire lasers, three different current configurations, n-blocking on p-substrate(VIPS), p-n-p-n blocking on n-substrate(VI(PN)nS), p-blocking on n-substrate(VINS) have been designed and fabricated. Among them VIPS laser showed the most stable characteristics of lasing up to 5 mW/facet, a threshold current of 39.9 mA at 818 nm, and an external differential quantum efficiency of 24 %/facet. The current tuning rate was almost linear 0.031 nm/mA, and the temperature tuning rate was measured to be 0.14 nm/$^{\circ}C$.

식품 안전 서비스를 위한 웹 기반 가상 공동 플랫폼 (A Cyber Collaboration Platform based on Web for Food Safety Service)

  • 고응남
    • 디지털콘텐츠학회 논문지
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    • 제16권1호
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    • pp.79-83
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    • 2015
  • 본 논문은 식품 안전 서비스를 위하여 웹 기반 가상 공동 플랫폼에 대해서 제안하였다. 본 시스템은 공동 작업에 참여한 사용자들이 다른 참여자들에게 같은 뷰로써 공유된 미디어들을 참조할 수 있도록 구축하였다. 본 논문에서는 N 스크린의 서버와 클라이언트 시스템을 통하여 식품 데이터의 신뢰성을 향상시키는 모델에 대해서 기술하였다. N 스크린의 기술과 웹 기반 멀티미디어 공동 작업에서 실행되는 기능에 대한 시스템의 기능 비교도 하였다.

Hydrolysis of p-Nitrophenyl Acetate and p-Nitrophenyldiphenyl Phosphate in Micellar Solution by N-Chloro Compounds : Involvement of Counter Ions in Micellar Catalysis

  • 박병덕;이윤식
    • Bulletin of the Korean Chemical Society
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    • 제16권10호
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    • pp.938-945
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    • 1995
  • Hydrolysis of p-nitrophenyl acetate (PNPA) and p-nitrophenyldiphenyl phosphate (PNPDPP) by N-chloro compounds in micellar solution were studied. N,N'-dichloroisocyanuric acid sodium salt (DCI) in cetyltrimethylammonium chloride (CTACl) micellar solution gave pseudo first-order kinetics. But, DCI in cetyltrimethylammonium bromide (CTABr) micellar solution showed typical series first-order kinetics - fast hydrolysis of the esters and concomitant slow decay of the hydrolyzed product, p-nitrophenolate. The hydrolysis rate was decreased as the hydrophobicity of N-chloro compounds was increased, which is the opposite trend to the usual bimolecular micellar reaction. This curious behavior of the N-chloro compounds in the catalytic hydrolysis of PNPA and PNPDPP in a cationic micellar system can be best explained by participation of counter ions of the surfactants during hydrolysis.

Synthesis of Polymers Having N-Hydroxymaleimide Units by Thermolysis of N-(Isopropyloxycarbonyloxy)maleimide Polymers

  • 안광덕
    • Bulletin of the Korean Chemical Society
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    • 제16권5호
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    • pp.443-449
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    • 1995
  • N-(Isopropyloxycarbonyloxy)maleimide (iPOCMI) has been synthesized and polymerized to give both the homopolymer and copolymers with substituted styrenes. These polymers were readily deprotected by thermolysis of the isopropyloxycarbonyl (iPOC) groups to provide the corresponding N-hydroxymaleimide (HOMI) polymers. The homopolymer and styrenic copolymers of iPOCMI were radically obtained in higher conversion and higher molecular weight than those obtained by direct polymerizations of N-hydroxymaleimide. The homopolymer of iPOCMI was transformed into poly(N-hydroxymaleimide)P(HOMI) by thermolysis of iPOC groups at 205 $^{\circ}C$ with concurrent release of propene and carbon dioxide. The copolymer of iPOCMI and styrene was thermally deprotected to the copolymer of HOMI and styrene at 235 $^{\circ}C.$ The mass loss was 28% and the Tg of the resulting copolymer was 250 $^{\circ}C.$ The thermal deprotection readily provided the desired, polar HOMI polymers which have Tgs above 240 $^{\circ}C.$ The deprotection was accompanied by large changes in aqueous base solubility.

Formulation of a New En Score in the Proficiency Test

  • Chul-Young Yi;In Jung Kim;Jong In Park;Yun Ho Kim;Young Min Seong
    • 한국의학물리학회지:의학물리
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    • 제35권1호
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    • pp.16-19
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    • 2024
  • A new En score of the proficiency test (PT) is formulated; it is applicable when a correlation exists between the reference and participant's values. Based on the uncertainty propagation rule given in ISO/IEC Guide 98-3 (GUM:1995), the En score covering the correlation case is newly developed for the PT. The new En score will be applied in a future PT organized by the Korea Research Institute of Standards and Science (KRISS) dosimetry team. The new En score will enhance measurement traceability and contribute to improving the quality management system of participants in the KRISS PT by avoiding performance underestimation.

잉여 수와 최소 반복 횟수를 이용한 CORDIC 성능 향상 (Performance Enhancement of CORDIC Employing Redundant Numbers and Minimal Iterations)

  • 김승열;유영갑
    • 한국콘텐츠학회논문지
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    • 제6권2호
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    • pp.162-168
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    • 2006
  • 본 논문에서는 최소 반복횟수를 갖고 잉여 수를 기반으로 하는 고성능 CORDIC 회로를 제안하였다. 최소 반복횟수는 계산미숙오차가 절단오차보다 작아지는 시점으로 결정하였다 최소 반복 횟수는 n이 입력 각도의 비트 수 일 때 n이 $n\geq16$이면 최소 반복 횟수는 n-4임을 알 수 있다. 이 CORDIC 회로는 잉여 수 시스템을 기반으로 변환 상수를 갖는 회로이다. 이 회로의 성능은 사인과 코사인을 계산하는데 {5 (n-4)+ 2[$log_{2}n$]}$\DeltaT$의 지연 시간을 갖는다.

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A Review of Domestic Research Trends Related to the International Classification of Functioning, Disability and Health (ICF): 2015-2020

  • Song, Ju-Min
    • 대한물리의학회지
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    • 제16권3호
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    • pp.65-80
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    • 2021
  • PURPOSE: This study was conducted as a literature review to analyze the research trends related to the International Classification of Functioning, Disability and Health (ICF) in Korea from 2015 to 2020. METHODS: Precedent studies were searched with the search term "ICF" or "international classification of functioning, disability and health" from the databases of RISS, KISS, DBpia, and Pubmed. The inclusion criteria are that the studies have been carried out in Korea from 2015 to 2020 using ICF by researchers consisting of one or more Koreans and have been peer-reviewed. RESULTS: Of the total 269 studies, 107 that met the inclusion criteria were analyzed. It was found that these studies were published at a similar frequency each year. The most common area of expertise was identified as the clinical area (n = 67), followed by special education (n = 21) and social welfare (n = 13). The study subject groups were mostly patients (n = 39), disabled people (n = 25), and related experts (n = 13). The most common research topic was functioning evaluation (n = 49) and followed by a literature review (n = 29), and the most frequently used components in all the areas of expertise were activity and participation (n = 98), body function and structure (n = 73), and environmental factors (n = 61). CONCLUSION: For the past six years, domestic ICF-related research has been conducted in a wider range of expertise areas on more subdivised subject groups. Continuous research, development of standardized curricula and contents, and development of coding tools are considered to be important in vitalizing the use of the ICF.

Formation and Dissociation Kinetics of Tetraaza-Crown-Alkanoic Acid Complexes of Cerium(Ⅲ)

  • 최기영;김동원;정용순;김창석;홍춘표;이용일
    • Bulletin of the Korean Chemical Society
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    • 제19권6호
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    • pp.671-676
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    • 1998
  • The formation and dissociation rates of $Ce^{3+}$ Complexes of the 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-NN', N",N"'-tetraacetic acid (1), 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-N,N',N",N"'-tetramethylacetic acid (2), and 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-N,N',N",N"'-tetrapropionic acid (3) have been measured by the use of stopped-flow spectrophotometry. Observations were made at 25.0±0.1 ℃ and at an ionic strength of 0.10 M $NaClO_4$. The complexation of $Ce^{3+}$ ion with 1 and 2 proceeds through the formation of an intermediate complex $(CeH_3L^{2+})^*$ in which the $Ce^{3+}$ ion is incompletely coordinated. This may then lead to be a final product in the rate-determining step. Between pH 4.76 and 5.76, the diprotonated $(H_2L^{2-})$ from is revealed to be a kinetically active species despite of its low concentration. The stability constants $(logK(CeH_3L^{2+}))$ and specific water-assisted rate constants $(k_{OH})$ of intermediate complexes have been determined from the kinetic data. The dissociation reactions of $Ce^{3+}$ complexes of 1, 2, and 3 were investigated with $Cu^{2+}$, ions as a scavenger in acetate buffer. All complexes exhibit acid-independent and acid-catalyzed contributions. The effect of buffer and $Cu^{2+}$ concentration on the dissociation rate has also been investigated. The ligand effect on the dissociation rate of $Ce^{3+}$ complexes is discussed in terms of the side-pendant arms and the chelate ring sizes of the ligands.

니겔라 사티바 오일의 미백 효능에 관한 연구 (Effect of Nigella sativa Oil on Melanogenesis)

  • 이수연;이새미;허우범;김진국;김영희
    • 대한화장품학회지
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    • 제37권4호
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    • pp.319-326
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    • 2011
  • 니겔라 사티바(Nigella sativa Linn.) 오일의 미백 효능을 확인하기 위하여 니겔라 사티바 오일 및 오일에서 분리된 유효성분들을 버섯 타이로시네이즈 효소, B16 멜라노마 세포를 이용하여 멜라닌 생성에 관련된 다양한 실험을 실시하였다. B16-F10 멜라노마 세포를 이용한 멜라닌 저해 활성시험 결과에서 니겔라 사티바 오일은 10 mg/mL의 농도에서 약 86 %의 멜라닌 생성을 억제하였으며, RT-PCR과 Western blot을 통한 멜라닌 생성 기작에 대한 영향을 조사한결과, 멜라닌 합성의 주요 단백질인 타이로시네이즈 발현 저해효과가 우수하게 나타났다. 또한, tyrosinase related protein-1 (TRP-1) 및 tyrosinase related protein-2 (TRP-2)의 발현이 억제되는 것을 확인하였다. 따라서, 니겔라 사티바오일은 멜라닌 생합성 저해 효과뿐만 아니라, 멜라닌 합성에 필수적인 효소(타이로시네이즈, TRP-1, TRP-2)의 발현저해를 통해 미백 효과를 나타내는 것으로 확인되었으며, 이에 따라 니겔라 사티바 오일은 멜라닌 생합성을 저해하는미백 소재로 활용할 수 있을 것으로 사료된다.