• 제목/요약/키워드: Seed addition method

검색결과 135건 처리시간 0.022초

Seed 첨가에 의한 Sr-Ferrite의 미세구조 제어 (Microstructure Control of Sr-Ferrite by Seed Addition)

  • 박준홍;신효순;이병교
    • 한국세라믹학회지
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    • 제32권1호
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    • pp.90-94
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    • 1995
  • In Sr-ferrite system, it has been attempted to inhibit the abnormal grian growth using Sr-ferrite powders synthesized by molten salt method as the matrix and the seeds, respectively. At each sintering temperature, the addition of seed more than 15% suppressed the abnormal grain growth, and the uniform microstructure resulted. Particularly, at 12$25^{\circ}C$, it was observed that the maximum number of the abnormal grain growth nuclei was achieved since the abnormal grain growth was suppressed even by the addition of 10% seed.

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Kaolin으로부터 Seed 첨가법에 의한 Mullite 합성 (Synthesis of Mullite from Kaolin by Seed Addition Method)

  • 김인섭;박주석;이명웅;이병하;소유영
    • 한국세라믹학회지
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    • 제35권8호
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    • pp.878-884
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    • 1998
  • Synthesis of high purity mullite from korean resourceful kaolin and water-soluble aluminium salts was in-vestigated by addition of mullite seed. Single phase of mullite was formed at 1350$^{\circ}C$ however its mullite con-tent was 31-33% Maximum content of mullite synthesized from kaoin aluminium nitrate and 8wt% mul-lite seed was 98% at 1600$^{\circ}C$ for 4 hours.

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Efficient Masked Implementation for SEED Based on Combined Masking

  • Kim, Hee-Seok;Cho, Young-In;Choi, Doo-Ho;Han, Dong-Guk;Hong, Seok-Hie
    • ETRI Journal
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    • 제33권2호
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    • pp.267-274
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    • 2011
  • This paper proposes an efficient masking method for the block cipher SEED that is standardized in Korea. The nonlinear parts of SEED consist of two S-boxes and modular additions. However, the masked version of these nonlinear parts requires excessive RAM usage and a large number of operations. Protecting SEED by the general masking method requires 512 bytes of RAM corresponding to masked S-boxes and a large number of operations corresponding to the masked addition. This paper proposes a new-style masked S-box which can reduce the amount of operations of the masking addition process as well as the RAM usage. The proposed masked SEED, equipped with the new-style masked S-box, reduces the RAM requirements to 288 bytes, and it also reduces the processing time by 38% compared with the masked SEED using the general masked S-box. The proposed method also applies to other block ciphers with the same nonlinear operations.

종자 입정을 이용한 저전압용 ZnO 바리스터의 제조 (Fabrication of Low Voltage ZnO Varistor by Seed Grain Method)

  • 강을손;성건용;김종희
    • 한국세라믹학회지
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    • 제27권4호
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    • pp.473-480
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    • 1990
  • Low-voltage ZnO-based varistors were made by seed grain method at various sintering conditions. Their microstructure and electrical properties were investigated and comlpared with those of the ZnO varistors made by a conventional method at the same sintering condition. During the sintering process, the added seed ZnO grain rapidly grew to be a gaint grain(above 500$\mu\textrm{m}$) provinding easy current path. Therefore the breakdown voltage was lowered as much as the order of 1/10-1/5 in comparison to that of the varistor made by a conventional method. But the grain size of the giant ZnO was little influenced by sintering condition, so the breakdown voltate was also little influenced. The weight loss was decreased by the addition of the seed grain, because the giant grain decreased the evaporation area. Therefore the nonobmic property of the specimen made by seed grain method was little influencedby sintering condition. In this research the low-voltage varistor made by seed grain method showed the least leakage current when sintered at 1150$^{\circ}C$ for zero hour.

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Extraction and Mixing Effects of Grape (Campbell) Seed Oil

  • Kang, Han-Chul;Min, Young-Kyoo;Hwang, Jong-Taek;Kim, Si-Dong;Kim, Tae-Su
    • Journal of Applied Biological Chemistry
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    • 제42권4호
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    • pp.175-179
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    • 1999
  • Grape seed oil was extracted using different preparatory treatments as follows: (1) grinding, (2) grinding and roasting, (3) grinding and wet- roasting, (4) grinding, roasting, and wet-roasting, and (5) grinding, wet-roasting, and wet-roasting. The highest antioxidant activity was obtained from the sample with the method (2). Initial states of oxidation were similar except method (1) that showed more oxidized state, being P.O.V.8. Acid values were observed in the range from 1.42 to 1.89. The lowest acid value was found as 1.42 in method (1) and those of others were somewhat higher, indicating that heating process of roasting produced some free fatty acids. From the results of sensory evaluation, the best odor and taste were obtained from the methods (2) and (3). Repetitive procedure of wet-roasting, like method 5, caused some loss of flavor components and decrease in the sensory evaluation score. Addition of grape seed oil (method 2) to soybean and perilla oil at the level of 20% retained considerable antioxidant activities as much as 4.3 and 5 times, respectively, than 100% soybean or perilla oil stored for 12 weeks. When soybean or perilla oil was mixed with 20% grape seed oils, P.O.V. decreased to half of that of unmixed oils.

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웰빙 중심 친환경 건축인증을 위한 연구 - 웰빙항목 도입을 위한 전문가 AHP 분석을 중심으로 - (Research on the well-being-centric green building certification - Focused on AHP Analysis of Expert Survey in order to introduce well-being criteria -)

  • 남혜령;이병연
    • KIEAE Journal
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    • 제16권6호
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    • pp.29-38
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    • 2016
  • Purpose: This study is conducted to contribute to the improvement of Green Standard for Energy and Environmental Design(G-SEED) from the existing energy physical efficiency-centric system to the well-being-centric green building certification system. Method: In order to modify existing G-SEED Certification, three phases of research have been conducted; 1) identification of needs of well-being-centric environment-friendly construction certification system, 2) comparison of domestic certification system with WELL Building standard(WELL) which focuses on human health and promotion of wellness and 3) AHP analysis to sort out the supplement items from WELL. Result: We proposed four alternatives which should be preferentially introduced to the existing domestic certification system; addition of independent 'well-being' section(field) in G-SEED, insertion of 'well-being' indicators in each relevant section of G-SEED, addition of 'well-being' indicators in 'Innovative Design(ID)' of G-SEED and independent score systems for 25 items in a high priority.

고 알루미나질 내화물에 미치는 Mullite의 영향(I) (Effect of Mullite on High Alumina Refractory (I))

  • 김인섭;김세훈;박주석;강지연;이경희;이병하
    • 한국세라믹학회지
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    • 제38권2호
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    • pp.128-136
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    • 2001
  • 본 연구에서는 kaolin을 이용하여 반기상법, gel coating법, seed 첨가법으로 mullite를 합성하였으며 mullite 15 wt%를 고 알루미나질 내화물 원료에 첨가하여 내화물 시편을 제조하였다. 제조된 시편의 물성을 분석한 결과 seed 첨가법으로 제조된 mullite를 첨가한 시편의 물성이 338.60 MPa의 꺾임강도와 9,427 kgf/$\textrm{cm}^2$의 압축강도값을 나타내었다. 제조된 시편의 내화도 및 잔존선팽창수축률을 측정한 결과 나머지 두가지 방법으로 합성한 mullite나 일반적인 고 알루미나질 내화물에 비하여 좋은 특성을 나타내었다.

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원본 지반운동 시간이력에 따른 스펙트럼 부합 시간이력의 특성 (Characteristics of Spectral Matched Ground Motions Time Histories According to Seed Ground Motion Selection)

  • 최다슬;지혜연;김정한
    • 한국지진공학회논문집
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    • 제25권1호
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    • pp.43-52
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    • 2021
  • According to several seismic design standards, a ground motion time history should be selected similar to the design response spectrum, or a ground motion time history should be modified by matching procedure to the design response spectrum through the time-domain method. For the response spectrum matching procedure, appropriate seed ground motions need to be selected to maintain recorded earthquake accelerogram characteristics. However, there are no specific criteria for selecting the seed ground motions for applying this methodology. In this study, the characteristics of ground motion time histories between seed motions and spectral matched motions were compared. Intensity measures used in the design were compared, and their change by spectral matching procedure was quantified. In addition, the seed ground motion sets were determined according to the response spectrum shape, and these sets analyzed the response of nonlinear and equivalent linear single degrees of freedom systems to present the seed motion selection conditions for spectral matching. As a result, several considerations for applying the time domain spectral matching method were presented.

Kinetically Controlled Growth of Gold Nanoplates and Nanorods via a One-Step Seed-Mediated Method

  • Hong, Soonchang;Acapulco, Jesus A.I. Jr.;Jang, Hee-Jeong;Kulkarni, Akshay S.;Park, Sungho
    • Bulletin of the Korean Chemical Society
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    • 제35권6호
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    • pp.1737-1742
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    • 2014
  • In this research, we further developed the one-step seed mediated method to synthesize gold nanoparticles (GNPs) and control their resulting shapes to obtain hexagonal, triangular, rod-shaped, and spherical gold nanostructures. Our method reveals that the reaction kinetics of formation of GNPs with different shapes can be controlled by the rate of addition of ascorbic acid, because this is the critical factor that dictates the energy barrier that needs to be overcome. This in turn affects the growth mechanism process, which involves the adsorption of growth species to gold nanoseeds. There were also observable trends in the dimensions of the GNPs according to different rates of addition of ascorbic acid. We performed further analyses to investigate and confirm the characteristics of the synthesized GNPs.

Cu seed layer 표면의 플라즈마 전처리가 Cu 전기도금 공정에 미치는 효과에 관한 연구 (Effects of Plasma Pretreatment of the Cu Seed Layer on Cu Electroplating)

  • 오준환;이성욱;이종무
    • 한국재료학회지
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    • 제11권9호
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    • pp.802-809
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    • 2001
  • Electroplating is an attractive alternative deposition method for copper with the need for a conformal and conductive seed layer In addition, the Cu seed layer should be highly pure so as not to compromise the effective resistivity of the filled copper interconnect structure. This seed layer requires low electrical resistivity, low levels of impurities, smooth interface, good adhesion to the barrier metal and low thickness concurrent with coherence for ensuring void-free fill. The electrical conductivity of the surface plays an important role in formation of initial Cu nuclei, Cu nucleation is much easier on the substrate with higher electrical conductivities. It is also known that the nucleation processes of Cu are very sensitive to surface condition. In this study, copper seed layers deposited by magnetron sputtering onto a tantalum nitride barrier layer were used for electroplating copper in the forward pulsed mode. Prior to electroplating a copper film, the Cu seed layer was cleaned by plasma H$_2$ and $N_2$. In the plasma treatment exposure tome was varied from 1 to 20 min and plasma power from 20 to 140W. Effects of plasma pretreatment to Cu seed/Tantalum nitride (TaN)/borophosphosilicate glass (BPSG) samples on electroplating of copper (Cu) films were investigated.

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