• 제목/요약/키워드: index properties

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고체 추진제의 기계물성 최적화 연구 (A Study on the Mechanical Properties Optimization of Solid Propellant)

  • 최용규;류태하;김낙현;김정은
    • 한국추진공학회지
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    • 제19권6호
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    • pp.91-97
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    • 2015
  • HTPB/AP/Al 계열의 혼합형 열경화 추진제를 적용한 로켓 연구개발에 있어서의 추진제 기계물성 규격을 정하는 일련의 과정을 고찰하고, 공정지수를 통하여 추진제 제조에서의 공정관리를 분석하였다. 이를 근간으로 기계물성간의 종속성을 분석하고 최적화 물성을 제시함으로서 불량률을 제거하는 공정 안전도 향상뿐만 아니라 추진제 그레인의 구조적 안전도 상승에도 기여할 것이다.

Kevlar-29 섬유강화 복합재료의 기계적 계면 특성 연구 (Studies on Mechanical Interfacial Properties of Kevlar-29 Fibers Reinforced Composites)

  • Park, Soo-Jin;Seo, Min-Kang;Ma, Tae-Jun;Lee, Jae-Rock
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2001년도 추계학술발표대회 논문집
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    • pp.158-162
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    • 2001
  • The effects of chemical treatment on Kevlar-29 fibers have been studied in a composite system. The surface characteristics of the Kevlar-29 fibers were characterized by pH, acid-base value and X-ray photoelectron spectroscopy (XPS). The mechanical interfacial properties of final composites were studied by interlaminar shear strength (ILSS) and critical stress intensity factor ($K_{IC}$). Also, the impact properties of the composites were investigated in the differentiating studies between initiation and propagation energies, and ductile index (DI) along with maximum farce and total energy. It was found that the chemical treatment with phosphoric acid ($H_3PO_4$) solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improving the mechanical interfacial strength of the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force in a composite system.

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한지의 강도적 성질 개선을 위한 전분류 처리 ( 제 2 보 ) -전분처리 한지의 표면과 강도적 성질과의 관계 - (Starch Treatment for the Improvement of Physical Properties of Hanji( II ) -Relationships between the physical properties and the surface characteristics of Hanji treated with various starches-)

  • 백승희;윤승락;조종수
    • 펄프종이기술
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    • 제38권2호
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    • pp.22-34
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    • 2006
  • To improve the mechanical properties of Hanji, starches such as maize, konyaku, and wheat powders were added at various concentrations in the manufacturing processes of Hanji. The effect of starches on the physical properties of Hanji was as follows. Filling rates of surface of hanji were increased with the increase of the concentration of starch. Hanji surface were completely filled at the 3.0% konyaku treatment. Konyaku powder showed higher filling rates than maize and wheat powder. The breaking length was increased with the increase of filling rates. Konyaku powder showed the highest breaking length: Tear index of hanji treated with maize and wheat powder were a little improved but that of hanji treated with konyaku powder were a little decreased compared to non-treated hanji. In conclusion, starch treatment showed the increase of the breaking length, but no effect on tear index.

닥나무 인피섬유의 절단장이 펄프화 및 한지의 물성에 미치는 영향(제1보) - 국산 닥 백피의 특성 - (The Effects of the Cutting Length of Paper Mulberry Bast Fiber on Pulping and Hanji Properties(I) - White bast of Korea grown paper mulberry -)

  • 임강혁;최태호
    • 펄프종이기술
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    • 제40권2호
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    • pp.57-64
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    • 2008
  • In general, the entire of paper mulberry bark, which is not cut into pieces with an appropriate length, have been used in the pulping. This kind of pulping method couldn't accomplish the improvement of beating and sheet forming efficiency. For this reason, we investigated the effects of the cutting length of paper mulberry bast fiber on pulping and Hanji (Korean traditional paper) properties, in order to develop high quality Hanji manufacturing process. The cutting length variation of paper mulberry white bast did not great effects on pulp yields. The pulp yields based on pulping methods were sulfomethylated pulping av. 57.4%, alkali-hydrogen peroxide pulping av. 55.4%, and alkaline pulping av. 53.5% respectively. The optical properties such as brightness, opacity, scattering coefficient, and absorption coefficient were slightly improved by the increase of paper mulberry white bast cutting length. The increase of paper mulberry white bast cutting length resulted in poor sheet formation. Physical properties such as breaking length, TEA, tear index, burst index, and folding endurance were slightly improved by the increase of cutting length. The modified pulping processes, which used sulfomethylated method and alkali-hydrogen peroxide method, showed better pulp and sheet properties than conventional alkaline pulping.

수분함량에 따른 율무가루의 점도변화 및 동적물성 특성에 관한 연구 (Viscosity and Dynamic Rheological Properties of Job's-tears as a Function of Moisture Content)

  • 윤원병;김병용;신동훈
    • 한국식품과학회지
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    • 제29권5호
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    • pp.932-938
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    • 1997
  • Changes in viscosity and dynamic theological properties of Job's-tears were measured by Bohlin dynamic tester as a function of moisture, and measurement was performed within a linear viscoelastic range. The result of the shear stress vs shear rate of Job's-tears at different moisture contents $(50{\sim}75%)$ was applied to mathematical models and Herschel-Bulkley model showed the highest correlation coefficient. Lower moisture content (55%) produced higher yield stress and consistency index, but lower flow behavior index, whereas higher moisture content showed reverse effects. Job's-tears with $50{\sim}70%$ moisture contents showed a higher storage modulus (G') than loss modulus (G') at all frequencies, showing a higher concentrated polymer characteristics. However, higher moisture content (>75%) showed crossover point between G' and G', and frequency dependency. As the moisture content was increased, the amount of viscoelastic properties such as G', G', complex viscosity decreased during heating, and initial temperature and miximum value of viscoelastic properties shifted to higher temperatures, representing the moisture-dependence of Job's-tears upon theological properties.

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분리유청단백질-이눌린 유래 마이야르 공액체의 기능적 특성 연구 (Functional Properties of Maillard Conjugates Made from Whey Protein Isolate and Inulin)

  • 김연우;이세희;이원재
    • Journal of Dairy Science and Biotechnology
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    • 제40권4호
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    • pp.143-150
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    • 2022
  • 본 연구에서는 분리유청단백질과 이눌린을 이용하여 마이야르 공액체를 성공적으로 제조하였다. 제조된 마이야르 공액체의 제조공정요인인 pH와 열처리 온도는 마이야르 공액체의 기능적 특성(유화특성, 표면특성, 항산화특성)에 영향을 미치는 핵심 제조공정임을 알 수 있었으며, 상대적으로 마이야르 반응이 활발한 pH 8.4와 열처리 온도 70℃에서 마이야르 공액체의 기능적 특성이 향상되었음을 확인하였다.

라이너지 공정수의 구성 성분이 종이의 물성에 미치는 영향 (The Effect of White Water Components on Mechanical Properties of Linerboard)

  • 윤혜정;류정용;송봉근;조미선
    • 펄프종이기술
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    • 제36권1호
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    • pp.9-15
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    • 2004
  • Micro inorganic solids and dissolved materials contained in the white water of linerboard process was obtained by centrifugation, and their characteristics were analyzed along with their effects on the mechanical properties of linerboard. Micro inorganic materials had little influence on tensile index and ZDT of UKP sheets. They showed rather a positive effect on mechanical properties of KOCC sheets due to adsorbed polymer. Mechanical properties of KOCC sheets decreased remarkably when the concentration of dissolved materials increased especially above 4000 ppm.

해성점토의 물리적 특성과 압축지수의 상관성 (Relationship Between Physical Properties and Compression Index for Marine Clay)

  • 김동후;김기웅;백영식
    • 한국지반공학회논문집
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    • 제19권6호
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    • pp.371-378
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    • 2003
  • 한반도 서, 남해안 해성점토에 대하여 초기간극비와 자연함수비 및 액성한계의 물리적 특성과 압축지수와의 상관성을 규명하기 위해 비교적 신뢰성이 크다고 볼 수 있는 대형 항만 공사용 최근자료를 분석하였다. 시료교란의 정도를 분석하기 위하여 각 표본별 실내압밀시험을 실시하고 Schmertmann이 제안한 방법으로 보정하여 수정압축지수를 산정하였다. 또한 이들 자료를 토대로 실내압밀시험으로부터 얻어진 압축지수를 경험적 방법에 의하여 보정한 후 현장 처녀압축곡선과의 관계를 분석하고, 단순회귀분석, 다중회귀분석 및 비선형 회귀분석을 실시하여 최적의 회귀모델을 구한 후 해성점토에 적용할 수 있는 토질특성과 시료교란의 영향을 고려한 압축지수와의 상관 관계식을 제안하였다. 분석 결과, 시료교란의 영향을 경험적 방법으로 평가해 본 결과 현장 압축지수는 실험실 압축지수의 1.16배정도 크게 평가되었다. 해성점토의 물리적 특성과 압축지수의 상관성에 대한 최적의 회귀모형은 토질정수의 누승식 또는 지수승식 형태의 비선형회귀식이 가장 적합한 것으로 나타났다. 또한, 설계 및 실무에 보다 쉽게 적용할 수 있도록 하기 위하여 선형관계식을 사용하는 경우에는 압축지수의 상관식을 물성치의 구간에 따라 구분하여 사용하는 것이 바람직하다.

겔라틴화(化)된 감자 전분(澱粉)의 리올로지 특성(特性) (Rheological Properties of Gelatinized Potato Starch)

  • 장영일;장규섭;박영덕
    • 농업과학연구
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    • 제18권1호
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    • pp.41-48
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    • 1991
  • 각(各) 조건별(條件別) 감자전분(澱粉) 호화액(湖化液)을 Brookfield 단원통(單圓筒) 회전점도계(回轉粘度計)로 실험(實驗)한 리올로지 특성(特性)을 살펴보면, 3-7%의 감자전분(澱粉) 호화액(湖化液)은 모두 강복응력(降伏應力)을 갖는 의가소성(擬可塑性) 유체(流體)로서 시간의존성(時間依存性) 구조붕괴(構造崩壞)를 나타내는 Thixotrophic 특성(特性)을 나타내었다. 여기서 점조도지수(粘租度指數)와 강복응력(降伏應力)은 농도(濃度)에 비례(比例)하였으나, 유동거동지수(流動擧動指數)는 각(各) 조건(條件)에서 일정(一定)한 관계(關係)를 보이지 않았다. 첨가제(添加製)인 인산염(燐酸鹽)을 첨가(添加)하였을 때 호화(湖化) 감자전분(澱粉)의 점조도지수(粘租度指數)와 강복응력(降伏應力)값은 크게 감소(減少)하였으나 유동거동지수(流動擧動指數)의 값은 약간 증가(增加) 하였다. 또한 4% 감자 전분(澱粉) 호화액(湖化液)에서 초기(初期) 및 평충상태(平衝狀態) 에서 활성화(活性化) 에너지를 측정(測定)한 값은 각각 1.52Kcal/g.mole과 1.27 Kcal/g.mole 이었다.

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Ganoderma lucidum균 전처리를 이용한 볏짚의 상압.소다펄프화

  • 주용찬;강진하
    • 펄프종이기술
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    • 제34권4호
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    • pp.51-60
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    • 2002
  • This study was carried out to develop the biochemical pulping method to enhance energy saving and decrease the capital cost through the soda pulping under atmospheric pressure (100%). Nonwood substrates, rice straw, were pretreated by white-rot fungi, Ganoderma Iucidum. It has acquired several basic data that can be applied in bio-soda pulping. The results of this study were as follow. Without any nutrients or with glucose, N and glucose+N the weight losses of rice straws inoculated by Canoderma Iucidum were 8.5~29.8%, 9.3~32% 11.8~30.1% and 11.8~24.4% respectively for 5, 10, 15, 20, 25 and 30 days incubation. The more extending incubation periods, the more increasing weight losses. The yield of untreated rice saw was 54.8% after pulping. When any nutrients was not added or glucose, N and glucose+N were added for the pretreatment, the total yields were ranged 50.6~38.5%, 48.6~34.4%, 47.2~38.4% and 49.5~42.6% respectively for 5, 10, 15, 20, 25 and 30 days incubation. The yields were gradually decreased based on extending of incubation. The physical properties of rice straw soda pulps without fungal treatment, the density, breaking length, burst index, tear index and folding endurance were 0.24 g/$\textrm{cm}^3$, 2.32 km, 0.91 kPa $m^2$/g, 56.7 mN.$m^2$/g and 35 times, respectively. After pretreatment without any nutrients or with glucose, N and glucose+N as nutrients the density was 0.27~0.30 g/$\textrm{cm}^3$, the breaking length 3.14~5.25 km, burst index 1.42~2.78 kPa.$\textrm{m}^2$/g, tear index45.8~64.5 mN.$\textrm{m}^2$/g and folding endurance 47~288 times at all incubating periods when pulping was done. The physical properties were increased with the increasing incubation periods. However, when glucose+N was added, the physical properties were shown superior results each incubating duration.