• 제목/요약/키워드: 3kW

검색결과 14,015건 처리시간 0.047초

레티닐 팔미테이트가 봉입된 셀룰로오스 나노입자의 제조 (Preparation of Cellulose Nanoparticles Loaded with Retinyl Palmitate)

  • 이정순;마상철;강기춘;표형배
    • 대한화장품학회지
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    • 제34권3호
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    • pp.175-181
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    • 2008
  • 생체 친화성 에칠셀룰로오스 막제를 사용하여 자발적인 유화확산에 의하여 레티닐 팔미테이트를 봉입한 나노입자를 제조하였다. 분산매인 유화제로는 폴리소로베이트 20, 폴리소르베이트 60, 피피지 26-부테스-26/피이지-40 하이드로제네이티드캐스터오일를 이용하여 제조하였으며, 본 결과로서 나노크기 입자를 제조하기에 가장 적절하며 안정한 조건은 1w/v% 에칠셀룰로오스와 3w/v% 폴리소그베이트 60 수용액을 이용한 것이었으며, 레티닐 팔미테이트의 봉입률을 최대화하기 위한 조건은 2w/v% 에칠셀룰로오스와 1w/v% 폴리소르베이트 60 수용액을 이용한 제조 조건이었다. 또한 이 최적 조건에 다른 유효성분에도 적용 가능한 것을 확인하였다.

5kW급 인라인 마이크로 수차 설계에 대한 연구 (The Study on Design of the 5kW Class Inline Micro-Turbine)

  • 박상언;노형운
    • 한국유체기계학회 논문집
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    • 제15권3호
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    • pp.32-38
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    • 2012
  • This paper is aimed to propose the design database(DB) of the inline micro-turbine for 5kW class. CFD analysis is performed to investigate the effect of a turbine on each parameter. This study showed that RadhaKrishna's data is different from the 5kW class in the low-head and the micro-turbine. Therefore, new DB for the design of inline micro-turbine for 5kW class could be needed. This study configured new design DB for the design of inline micro-turbine for 5kW class. The DB of this study showed that the optimal hub ratio(Dp/DR), the optimal body ratio(Db/DR) and the optimal range of body length ratio(Lh/DR) is 50%, 1.1 and 2.3 to 2.9, respectively.

ON w-COPURE FLAT MODULES AND DIMENSION

  • Bouba, El Mehdi;Kim, Hwankoo;Tamekkante, Mohammed
    • 대한수학회보
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    • 제57권3호
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    • pp.763-780
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    • 2020
  • Let R be a commutative ring. An R-module M is said to be w-flat if Tor R1 (M, N) is GV -torsion for any R-module N. It is known that every flat module is w-flat, but the converse is not true in general. The w-flat dimension of a module is defined in terms of w-flat resolutions. In this paper, we study the w-flat dimension of an injective w-module. To do so, we introduce and study the so-called w-copure (resp., strongly w-copure) flat modules and the w-copure flat dimensions for modules and rings. The relations between the introduced dimensions and other (classical) homological dimensions are discussed. We also study change of rings theorems for the w-copure flat dimension in various contexts. Finally some illustrative examples regarding the introduced concepts are given.

MicroRNA expression profiling during the suckling-to-weaning transition in pigs

  • Jang, Hyun Jun;Lee, Sang In
    • Journal of Animal Science and Technology
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    • 제63권4호
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    • pp.854-863
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    • 2021
  • Weaning induces physiological changes in intestinal development that affect pigs' growth performance and susceptibility to disease. As a posttranscriptional regulator, microRNAs (miRNAs) regulate cellular homeostasis during intestinal development. We performed small RNA expression profiling in the small intestine of piglets before weaning (BW), 1 week after weaning (1W), and 2 weeks after weaning (2W) to identify weaning-associated differentially expressed miRNAs. We identified 38 differentially expressed miRNAs with varying expression levels among BW, 1W, and 2W. Then, we classified expression patterns of the identified miRNAs into four types. ssc-miR-196a and ssc-miR-451 represent pattern 1, which had an increased expression at 1W and a decreased expression at 2W. ssc-miR-499-5p represents pattern 2, which had an increased expression at 1W and a stable expression at 2W. ssc-miR-7135-3p and ssc-miR-144 represent pattern 3, which had a stable expression at 1W and a decreased expression at 2W. Eleven miRNAs (ssc-miR-542-3p, ssc-miR-214, ssc-miR-758, ssc-miR-4331, ssc-miR-105-1, ssc-miR-1285, ssc-miR-10a-5p, ssc-miR-4332, ssc-miR-503, ssc-miR-6782-3p, and ssc-miR-424-5p) represent pattern 4, which had a decreased expression at 1W and a stable expression at 2W. Moreover, we identified 133 candidate targets for miR-196a using a target prediction database. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that the target genes were associated with 19 biological processes, 4 cellular components, 8 molecular functions, and 7 KEGG pathways, including anterior/posterior pattern specification as well as the cancer, PI3K-Akt, MAPK, GnRH, and neurotrophin signaling pathways. These findings suggest that miRNAs regulate the development of the small intestine during the weaning process in piglets by anterior/posterior pattern specification as well as the cancer, PI3K-Akt, MAPK, GnRH, and neurotrophin signaling pathways.

W-대역 영상레이다를 위한 광대역 Chirp 신호 발생장치 (Wideband Chirp Signal Generation for W-Band SAR)

  • 이명환;정진미;이준섭;;김용훈
    • 한국전자파학회논문지
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    • 제29권2호
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    • pp.138-141
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    • 2018
  • 본 논문에서는 FPGA를 이용하여 디지틀 방식으로 영상 레이다에 사용하는 주파수 변조된 첩(Chirp) 신호를 생성하고, 이 신호를 I-Q 변조하여 RF 신호로 변환 한 후 24 주파수 체배기로 체배하여 94 GHz W-대역에서 광대역 첩 신호발생 장치의 설계, 제작한 연구 결과를 제시한다. 개발된 첩 발생기는 94 GHz의 캐리어 주파수와 960 MHz의 대역폭을 가지는 주파수 변조된 신호이며, 평탄도는 IF단(3.9 GHz)에서 1 dB 이내, W-대역에서 2 dB 이내 그리고 3 W의 출력을 보여주고 있다.

원심분사주조법에 의한 $Cu-X(=Al_2O_3,W)_p$ 복합재료의 미세조직 및 복합화 (Compositing Modes and Microstructures of $Cu-X(=Al_2O_3,W)_p$ Composite by Centrifugal Spray-Cast Deposition)

  • 배차헌;정해용
    • 한국주조공학회지
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    • 제17권5호
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    • pp.480-487
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    • 1997
  • Particle reinforced metal matrix composites(MMCs) via a centrifugal spray-cast deposition(CSD) process were fabricated by injecting second phase particles($Al_2O_3$<40${\mu}m$, W<17.3${\mu}m$) into copper melt on the atomizing disc. Compositing modes were investigated by combining microstructures and mathematical modeling between Cu droplets and the reinforced particles injected. The $Cu/W_P$ powders were shown that the W particles penetrate and get embedded in the Cu droplets. It is considered that the W particles composite preferentially in Cu melt on the atomizing disc. On the other hand, the $Al_2O_3$, particles did not penetrate into the Cu droplets on the atomizing disc but get attached in surface of Cu droplets during the flight. It is considered that the compositing may be attained in the flight distance which the relative velocity between Cu droplet and $Al_2O_3$, particle is maximum. The microstructure of the $Cu/W_P$ and the $Cu/(Al_2O_3)_p$ composite preform was strongly influenced by compositing modes of droplets, and after subsequent deposition it was comprised as it is called the dispersed type and the cell type of microstructure, respectively.

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모델 테스트에 의한 Bulldozer Blade의 견인력(牽引力) 예측(豫測) (Draft Prediction of Bulldozer Blade by Model Tests)

  • 이규승;노상철
    • Journal of Biosystems Engineering
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    • 제18권3호
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    • pp.209-219
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    • 1993
  • A series of soil bin experiment was carried out on sand to investigate if true model theory is applicable to blade-soil system and finally to find mathematical relationship between the dimensionless terms which contain the blade-soil parameters. The following conclusions were derived from the study. 1. It was proved that the draft of the prototype blade can be predicted without distortion by those of model blades with the length scale of 1.2, 2 and 2.4. 2. For the sand, bulk density was found to be a good measure of soil physical properties which are pertinent to predict the draft of the blade-soil system. 3. The mathematical relationship between $D/{\gamma}W$ and d/W, ${\beta}$, and $V^2/Wg$ are as follows ; $$\frac{D}{{\gamma}W^3}=124.98[\frac{d}{W}]^2+7.16[\frac{d}{W}]+0.43 \\ \frac{D}{{\gamma}W^3}=-0.00099{\beta}^2+0.13{\beta}-2.01 \\ \frac{D}{{\gamma}W^3}=0.041[\frac{V^2}{Wg}]^2+0.08[\frac{V^2}{Wg}]+1.3$$

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건축용 목재의 열 유해성 평가에 대한 연구 (A Study on the Heat Hazard Assessment of Building Wood)

  • 우태영;진의;정영진
    • 한국화재소방학회논문지
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    • 제32권5호
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    • pp.6-14
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    • 2018
  • 본 연구는 건축용 목재의 화재위험성에대하여 열방출 특성을 중심으로 조사하였다. 열방출 성질은 cone calorimeter (ISO 5660-1)를 이용하여 측정하였으며 4종의 목재를 사용하였다. 외부 열유속 $25kW/m^2$에서 연소시킨 후 측정된 착화시간은 35 s부터 55 s까지였다. 나왕(lauan)과 적송의 착화 시간은 각각 54 s, 55 s로 가장 지연된 값으로 얻어졌다. 최대열방출율은 $156.87{\sim}235.1kW/m^2$ 였고 화재초기의 위험성은 가문비나무가 가장 높았다. 삼나무의 평균유효연소열은 19.1 MJ/kg였고 시료들 중에서 가장 높게 나타났다. 화재성능지수(FPI)에 의한 목재의 화재위험성은 나왕($0.2468s{\cdot}m^2/kW$) < 적송($0.2339s{\cdot}m^2/kW$) < 가문비나무($0.2308s{\cdot}m^2/kW$) < 삼나무($0.2231s{\cdot}m^2/kW$) 순으로 높았고 화재성장지수(FGI)에 의한 목재의 화재위험성은 나왕($0.5088kW/m^2{\cdot}s$) < 적송($0.511kW/m^2{\cdot}s$) < 삼나무 ($2.8522kW/m^2{\cdot}s$) < 가문비나무($3.0662kW/m^2{\cdot}s$) 순으로 높았다. 그러므로 목재의 열방출 특성에 대한 화재위험성은 가문비나무와 삼나무가 높은 것으로 나타났다.

다결정 3C-SiC/TiW Ohmic Contact에 관한 연구 (Study for ohmic contact of polycrystalline 3C-SiC/TiW)

  • 온창민;정귀상
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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    • pp.1311-1312
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    • 2006
  • This paper describes the ohmic contact formation between a TiW film as a contact material deposied by RF magnetron sputter and polycrystalline 3C-SiC films deposied on thermally grown Si wafers. The specific contact resistance (${\rho}_c$) of the TiW contact was measured by using 4he C-TLM. The contact phase and interfacial reaction between TiW and 3C-SiC at high-temperature were also analyzed by XRD and SEM. All of the samples didn't show cracks of the TiW film and any interfacial reaction after annealing. Especially, when the sample was annealed at $800^{\circ}$ for 30min., the lowest contact resistivity of $2.90{\times}10^{-5}{\Omega}{\cdot}cm^2$ of was obtained due to the improved interfacial adhesion.

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