• Title/Summary/Keyword: 입도 크기

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Variation of strength of soil matrix with artificially manipulating particle distribution of granular soil (인위적 입도조정에 따른 지반의 강도특성 변화)

  • Moon, Jun-Ho;Xin, Zhen-Hua;Kim, Gab-Boo;Moon, Sun-Mi;Kim, Young-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.1
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    • pp.56-62
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    • 2018
  • In this study, an artificially formed Gap graded soil, designed to increase its shear strength, was analyzed to determine the strength parameters through direct shear tests. Uniform and fine grain size samples were compared to the Gap graded soil to investigate the increase in the shear strength. Plate loading tests were conducted using 13mm and 19mm aggregates to confirm the reproducibility of the strength enhanced samples for site application. This test confirmed that the particle size ratio and the internal friction angle are correlated to the shear strength, and the shear resistance angle significantly increased in the specific particle size ratio range. The calculation of the ultimate bearing capacity by the plate load test demonstrated that the grain size adjustment method greatly influences the strength increase rate. Therefore, the findings were verified and it was confirmed that a high shear strength is achievable despite the existence of a poor particle size distribution.

Human-like Fuzzy Lip Synchronization of 3D Facial Model Based on Speech Speed (발화속도를 고려한 3차원 얼굴 모형의 퍼지 모델 기반 립싱크 구현)

  • Park Jong-Ryul;Choi Cheol-Wan;Park Min-Yong
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2006.05a
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    • pp.416-419
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    • 2006
  • 본 논문에서는 음성 속도를 고려한 새로운 립싱크 방법에 대해서 제안한다. 실험을 통해 구축한 데이터베이스로부터 음성속도와 입모양 및 크기와의 관계를 퍼지 알고리즘을 이용하여 정립하였다. 기존 립싱크 방법은 음성 속도를 고려하지 않기 때문에 말의 속도와 상관없이 일정한 입술의 모양과 크기를 보여준다. 본 논문에서 제안한 방법은 음성 속도와 입술 모양의 관계를 적용하여 보다 인간에 근접한 립싱크의 구현이 가능하다. 또한 퍼지 이론을 사용함으로써 수치적으로 정확하게 표현할 수 없는 애매한 입 크기와 모양의 변화를 모델링 할 수 있다. 이를 증명하기 위해 제안된 립싱크 알고리즘과 기존의 방법을 비교하고 3차원 그래픽 플랫폼을 제작하여 실제 응용 프로그램에 적용한다.

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Effect of Grinding Methods on Particle Size and Crystalline Structure of Copper Phthalocyanine (분쇄방법에 따른 구리프탈로시아닌 입자크기 및 결정구조 변화)

  • Lee, Jeong Se;Lee, Hak Sung
    • Applied Chemistry for Engineering
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    • v.18 no.1
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    • pp.41-47
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    • 2007
  • Crude copper phthalocyanine (Cupc) was synthesized by Wyler process, then grounded using various methods such as acid pasting, kneader, attritor and SC-mill. Particle size, shape and crystalline structure were compared and evaluated after particle size reductions. Cupcs prepared by acid pasting and kneader methods that are excellent manufacturing processes in industry were used as our standards. Particle properties of Cupcs prepared either by attritor or by SC-mill were compared with particle size analyzer, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Particle size analyzer and SEM were used to analyze the variation of particle sizes of Cupc with milling time. Particle size was initially decreased up to the 90 min of milling time, thereafter it reversely began to increase in case of SC-mill. Cupc obtained from dry milling with attritor displayed strong cohesion so that particle size was not possible to determine with particle size analyzer. However, the optimum milling time was indirectly approximated from the analysis of XRD peak intensity.

Electrochemical Properties of Sub-micron Size Si Anode Materials Distributed by Wet Sedimentation Method (습식 분급으로 입도 조절된 서브 마이크론 크기의 Si 음극활물질의 전기화학적 특성 분석)

  • Jin-Seong Seo;Hyun-Su Kim;Byung-Ki Na
    • Korean Chemical Engineering Research
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    • v.61 no.1
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    • pp.39-44
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    • 2023
  • In this study, the particle size of Si polycrystals was controlled through wet-sedimentation method, and changes in the capacity and cyclic characteristics of the Si anode material according to the particle size were observed. After wet-sedimentation of Si particles pulverized by a vibration mill, the non-uniform particle distribution of Si was uniformly controlled. The d50 of a sample in which Si was sedimented for 24 hours decreased to 0.50 ㎛. As a result of the electrochemical characteristic analysis, the Rct value representing the resistance in the electrode was significantly reduced due to the decrease in particle size. The unclassified Si sample exhibited a discharge capacity of 2,869 mAh/g in the first cycle, and decreased to 85.7 mAh/g after 100 cycles. The sample in which Si was classified for 24 hours showed a capacity of 3,394 mAh/g initially, and maintained a capacity of 1,726 mAh/g after 100 cycles. As the size of the Si particles decreased, the discharge capacity increased and the cycle life was also increased.

FeO, $TiH_2$, Carbon 원료분말을 이용한 Fe-TiC 나노 복합분말 제조 및 소결

  • An, Gi-Bong;Kim, Ji-Sun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.10a
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    • pp.26-26
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    • 2011
  • Fe계 TiC 합금은 미량의 합금원소를 첨가시켜 경화능, 내식성, 내마모성 성질을 개선한 특수 공구용 재료로서 현재 절삭, 내마모성, 광산, 금형재료 등의 분야에 널리 사용되고 있다. 금속과 세라믹의 복합재료인 초경합금은 비열처리용 공구강으로 WC, TiC 등의 4, 5, 6족 금속탄화물에 Co, Ni, Fe등의 철족이 결합금속으로 소결한 복합재료로 WC-Co계 초경합금이 주종을 이루고 있으나, 전략 소재로서 고가인 Co 원료를 대체하기 위한 재료로서 초경재료의 고경도와 공구강의 경제성 및 가공성의 장점을 이용한 Fe-TiC계 초경합금의 연구가 다양하게 진행되고 있다. 본 연구에서는 Fe기지에 서브마이크론 크기의 미세한 TiC 입자가 균일하게 분산된 Fe-TiC 복합분말을 경제적으로 제조하기 위해 순수한 Fe, Ti 원료분말에 비해 단가가 낮고 미세 분쇄가 용이한 FeO, $TiH_2$ 분말을 고에너지 밀링 후 반응 열처리 시키는 유사 기계화학적 공정을 시도하였다. 조성비 Fe-30wt%TiC 복합분말을 제조하기위해 마이크론(micron) 크기의 FeO, $TiH_2$, C 분말을 사용하였고, 1단계로 FeO와 C을 고에너지 밀링으로 혼합 후 반응시켜 환원시키는 공정과 2단계로 이렇게 환원된 분말과 TiH2를 고에너지 밀링으로 다시 혼합, 분쇄한 후 반응열처리 하는 두 단계 공정을 사용하였다. FeO의 환원 단계에서는 $700{\sim}1,000^{\circ}C$ 온도 범위에서 1시간 유지하였고, 고에너지 밀링 시 밀링시간, 회전속도를 변수로 두고 실험하였다. 환원된 분말은 수평관상로를 이용해 아르곤분위기에서 $1,000{\sim}1300^{\circ}C$까지 1시간 유지하여 반응열처리시켜 Fe-TiC 복합분말을 제조하였다. 준비된 복합분말을 XRD와 FE-SEM, EDS, 입도분석기 (LPSA) 등을 이용해 분말의 형태와 특성, 상, 조성, 입도, 분산도 등을 조사하였다. 제조된 Fe-TiC 나노복합분말을 방전플라즈마소결(SPS) 과 상압소결 실험을 진행하였다. Fe-TiC 복합분말 제조공정의 첫 번째 단계인 FeO의 환원반응은 $800^{\circ}C$이상의 온도에서 Fe로 환원이 진행됨을 확인하였다. 두 번째 단계인 반응열처리공정에서는 $1,000^{\circ}C$ 이상에서 TiC가 형성됨을 XRD 상분석을 통해 확인할 수 있었고, $1,100^{\circ}C$ 이상의 온도에서 반응열처리를 했을 때 XRD 분석결과와 산소 조성 분석 결과로부터 반응의 완결성과 순도에서 최적 온도 조건임을 확인하였다. 온도를 $1,300^{\circ}C$로 증가시킬 경우 반응의 완결성에 큰 변화가 없는 반면 분말입자간의 목형성이 일어나 가소결 되는 것을 FE-SEM을 통해 관찰하였다. 또한 최적조건으로 제조된 Fe-TiC 복합분말의 입도분석과 FE-SEM/EDS 관찰/분석을 시행한 결과 평균 입도 0.6 ${\mu}m$의 미세한 Fe-TiC 복합분말 내에 Fe분말 주변과 내부에 나노크기의 TiC입자가 균일하게 분산되어 존재하는 것을 확인하였다.

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Effect of Solvent Content on Morphology and Rubber Particle Size Distribution of High Impact Polystyrene (용매 함량이 내충격성 폴리스티렌의 형태구조 및 고무 입도분포에 미치는 영향)

  • 정한균;박정신;장대석;이성재
    • Polymer(Korea)
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    • v.26 no.3
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    • pp.307-315
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    • 2002
  • Major factors affecting the impact resistance of high impact polystyrene (HIPS), the rubber-toughened grade of polystyrene, are rubber-phase particle size and size distribution, molecular weight, morphology, and degree of grafting. Accordingly, it is important to control or investigate these factors. In this study, the effect of solvent content was analyzed by the morphology and particle size distribution of rubber phase, and final properties in bulk-solution polymerization of HIPS. The prepolymerization time was, first, determined by measuring the evolution of particle size distribution of dispersed phase to explain the phase inversion with time. As the solvent content increased, the size of rubber particle increased and then gradually decreased. Rubber-phase morphology was likely to have higher degree of grafting as the solvent content increased. Rheological and mechanical properties decreased as the solvent content increased because of the decrease of matrix molecular weight due to the chain transfer reaction to solvent and the existence of residual solvent. Nevertheless, the impact resistance seemed to increase when the rubber particle size increased.

Change of Calcium Carbonate Crystal Size at steady state in CMSMPR(Continuous Mixed Suspension Mixed Produce Removal) Crystallizer (연속식결정화기 정상상태에서 탄산칼슘 결정크기 변화)

  • Han, Hyun Kak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.7
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    • pp.714-719
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    • 2017
  • The controlled synthesis of inorganic materials with a specific size and morphology is an important factor in the development of new materials in many fields, such as nanoparticles, medicine, electronics, semiconductors, pharmaceutical sand cosmetics. Solution crystallization is one of the most widely used separation processes in the chemical and pharmaceutical industries. Calcium carbonate has attracted a great deal of attention in industry because of its numerous applications. The mean crystal size, crystal size distribution and morphology are important factors in the continuous crystallization process. In this study, the continuous crystallization of calcium carbonate by the calcium chloride process was investigated. The mean crystal size and crystal size distribution data were obtained by a particle size analyzer. The morphological imaging of the crystalswasper formed by SEM. Under steady state operation, the mean crystal size change was small, but increasing the input concentration and mixing rate increased the crystal size. In this operation, some aragonite was found, but the main crystal phase was calcite.

Size of Bedload Materials and Bedload in Mountainous River (산지하천의 하상재료와 소류사의 크기)

  • Park, Sang-Deog;Kim, Gun-Tae;Kim, Ho-Seop;Lee, Seung-Kyu;Shin, Seung-Sook
    • Proceedings of the Korea Water Resources Association Conference
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    • 2010.05a
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    • pp.556-560
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    • 2010
  • 자갈하상 산지하천의 주요 관심사는 소류사 크기 분포와 연계하여 하상재료의 이송에 대한 광범위의 기초자료 확보하는 것이다. 자갈 하상재료가 주를 이루는 강원영동지역 양양남대천의 산지 하천을 대상으로 하상재료를 조사하였다. 산지하천의 소류사 크기를 고려한 소류사 채집기를 설치하고, 호우 발생 이후 측정기에 포획된 소류사의 크기를 파악하기 위해 입도분포를 분석하였다. 두 개의 소류사 측정기는 지남교 지점에 유속이 빠른 우안과 유속이 상대적으로 느린 좌안에 각각 설치하였다. 산지하천 시험구간의 하상재료 분포도는 그림 1과 같으며, 하상재료 평균입경은 184.65mm 이였다. 연구단에서 운영중인 법수치 우량관측소의 관측자료에 따르면, 2009년 11월 1~13일 185mm 강우가 발생하였으며, 11월 11일 7:00경에 최대수위에 따른 첨두유출량 107.23$m^3/s$가 발생하였다. 첨두유출 발생당시 이동한 우안 소류사의 평균입경은 102.88mm 이였고, 좌안 소류사의 평균입경은 66.53mm 이였다(그림 2). 하상재료의 평균입경에 대한 소류사 평균입경을 비교하였을 때, 소류사는 하상재료의 $45.87{\pm}13.92%$ 크기 범위에서 이동함을 확인하였다.

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Effect of HAZ Softening Zone on Creep Rupture Properties of 1.0Cr-1.0Mo-0.25V Turbine Rotor Steels - Part I : Creep Rupture Life- (1.0Cr-1.0Mo-0.25V 터어빈 로터강의 열영향부 연화층이 크립 파단 특성에 미치는 영향 -Part I : 크립 파단 수명 -)

  • ;Indacochea, J. E.
    • Journal of Welding and Joining
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    • v.15 no.1
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    • pp.92-100
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    • 1997
  • Weld repair of ASTM A-470 class 8 high pressure (HP) steam turbine rotor steel has been performed to extend the service life of older fossil units. Microhardness measurements were conducted across the weldment from unaffected base metal (BM) to weld metal (WM). The hardness of the BM was VHN 253, however it dropped up to VHN 227 at the heat affected zone (HAZ) close to unaffected BM for multipass SAW. This area of hardness drop is called "siftening zone" and has a width of 0.5-0.6mm. During creep rupture test, failure occurred around the softening zone and rupture time was 772.4hr at 19Ksi (132 Mpa) and 593.deg. C. Multipass MIG and TIG welding have been employed to reduce the softening zone width. The softening zone width for MIG was 0.3-0.4mm and for TIG was zero-0.4mm depending on heat inputs. However creep rupture time was decreased as softening zone width reduced. Creep rupture time also showed a close relationship with heat inputs in TIG process. The higher heat input, the longer rupture time. Most failure occurred at intercritical HAZ (ICHAZ), however rupture location was shifted to coarse grained HAZ (CGHAZ) as heat input decreased. The rupture surface showed tearing and dimple which indicated transgranular fracture. fracture.

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Prediction of Hindered Settling Velocity of Bidisperse Suspensions (이중 입도 분포를 가진 현탁액의 침강 속도 예측)

  • Koo, Sangkyun
    • Applied Chemistry for Engineering
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    • v.19 no.6
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    • pp.609-616
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    • 2008
  • The present study is concerned with a simple numerical method for estimating the hindered settling velocity of noncolloidal suspensions with bidisperse size distribution of particles. The method is based on an effective-medium theory which uses the conditional ensemble averages for describing the velocity fields or other physical quantities of interest in the suspension system with the particles randomly placed. The effective-medium theory originally developed by Acrivos and Chang[1] for monodisperse suspensions is modified for the bidisperse case. Using the radial distribution functions and stream functions the hindered settling velocity of the suspended particles is calculated numerically. The predictions by the present method are compared with the previous experimental results by Davis and Birdsell[2] and Cheung et al.[3]. It is shown that the estimations by the effective-medium model of the present study reasonably agree with the experimental results.