• 펄프종이기술
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• 제40권1호
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• pp.9-14
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• 2008

Beating and using chemical agents are common methods to improve physical properties. But the beating is high energy consumption process and chemical agent addition may cause deteriorate waste water quality. Therefore, it is necessary to use more environment-friendly methods. In this study, micro pulp was used in the handsheet making to get improving effects of physical properties without beating treatment and chemicals. Stiffness, thickness and air permeability were increased and strength properties of paper were also improved to some extents by only the micro pulp addition.

• 아시안잔디학회지
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• 제5권2호
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• pp.81-86
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• 1991

The sludge, a waste of brewery industries, was examined for potentials as a natural organic fertilizer (or soil conditioner) for lawn. Trial products were measured for changes of physical, chemical properties in laboratory and seed germination and seedling growth in green house were also tested. The results are as the following:1The sludge from distilled liquor brewery contained high quantity of organic matter which had proper physical and chemical properties for lawn fertilizer (natural organic fertilizer, soil conditioner, top-dressing mix) . It showed good characteristics in handling and capabilities to be developed as commercial products for golf courses. 2.Sludge from beer company needs proper treatment to improve physical properties for futher degradiation. It is because aggregation of the sludge particles prevented microbial activities and changing to soluble form. 3.Green carbon can be used as carbon source for organic fertilizer production using brewery sludge, but it should not contain wood extract which inhibit seed germination and seedling growth.

• 폴리머
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• 제27권5호
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• pp.502-507
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• 2003

메탈로센 선형 저밀도 폴리에틸렌 (m-LLDPE)과 저밀도 폴리에틸렌 (LDPE)을 용응 블렌딩 방법으로 블렌드를 제조하여 열적 거동 및 물성을 관찰하였다. LDPE/m-LLDPE1 블렌드는 LDPE조성이 50% 이상이면 두 개의 용융 피크가 관찰된 반면 다른 블렌드들은 단일한 용융 피크를 나타내었다. m-LLDPE에서 공단량체 함량이 감소할수록 용융 온도와 상대 결정화도가 증가하였다. 공단량체 함량이 2 wt%인 m-LLDPE1이 초기 탄성률이 가장 높게 관찰되었고, 공단량체 함량이 증가함에 따라 감소하였다. 블렌드에서 조성에 따른 초기 탄성률의 변화는 상대 결정화도의 거동과 유사하게 나타났다. 블렌드의 파괴 신율은 LDPE/m-LLDPE1과 LDPE/m-LLDPE2 블렌드에서 평균값보다 낮은 파괴 신율을 나타내었었다. m-LLDPE2의 용융 지수가 가장 높게 관찰되었고 공단량체 함량이 증가함에 따라 감소하는 경향을 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2839-2842
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• 2014

• 폴리머
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• 제33권4호
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• pp.384-388
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• 2009

폴리아크릴로니트릴(PAN)과 셀룰로오스 아세테이트(CA) 블렌드/디메틸포름아미드(DMF) 용액의 유변학적 특성을 온도와 블렌드 조성비에 대하여 조사하였다. 모든 고분자 용액이 온도 변화에 따라 매우 특징적인 유변학적 거동을 보였다. 8 wt% 용액의 경우 $20{\sim}60^{\circ}C$ 온도범위에서 온도의 증가와 더불어 용액의 점도가 증가하고 손실탄젠트값이 감소하였다. $20^{\circ}C$에서는 용액의 물성이 블렌드의 조성에 영향을 받았으나 40 및 $60^{\circ}C$에서는 조성비가 용액 물성에 미치는 영향이 크게 감소하였다. 더 높은 온도에서의 더 긴 분자 이완시간으로부터 온도가 증가함에 따라 분자간력에 의한 물리적 구조 형성이 촉진된다는 것을 알 수 있었다. 이러한 유변학적 특성에 대한 원인은 묽은 용액의 특성으로부터 유추할 수 있었다. 고분자 용액의 고유점도가 온도가 증가함에 따라 감소하였다.

• 지질공학
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• 제27권4호
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• pp.451-462
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• 2017

Physical weathering caused by external forces and chemical weathering caused by the decomposition or alteration of constituent materials are the two factors that dominate the mechanical properties of rocks. In this study, a field investigation was undertaken to identify the physical and chemical weathering characteristics of the biotite granite and granitic weathered soils in Gyeongju, South Korea. Samples were collected according to their grade of weathering and subjected to modal analysis, XRD analysis, XRF analysis, physical property tests, particle size distribution tests, and slake durability tests. Modal and XRD analysis identified these rocks as biotite granite; secondary alteration minerals were not observed. Physical property tests and particle size distribution analyses indicate an average porosity of 41.28% and a sand content of > 90 wt.%. These values are somewhat higher than those of granites in general. The results of the slake durability test and XRF analyses show that the physical and chemical weathering indices of the samples vary with the degree of weathering.

• 한국가구학회지
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• 제18권1호
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• pp.39-46
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• 2007

This study was carried out to investigate the wood properties for efficient utilization of warm temperate tree species of Quercus acuta Thunb. grown in Korea. Fundamental wood properties in the anatomical, physical, mechanical and chemical characteristics were examined. Quercus acuta Thunb. is a radial-porous, straight grained and fine textured wood. The heartwood is not clearly distinguished from the sapwood. In physical properties, it has a high oven-dry specific gravity of $0.85{\pm}0.02$, and high shrinkage from green to air-dried condition of $7.05{\pm}0.52%$ in radial and $11.13{\pm}0.48%$ in tangential direction. Mechanical properties determined are strong with the MOR of $1,065{\pm}90kgf/cm^2$, and tensile strength parallel to grain of $1,490{\pm}258kgf/cm^2$ and shear strength of $175{\pm}13kgf/cm^2$. Also, this wood has high extractive contents: 11.11% for cold and 13.51% for hot water.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.196-200
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• 2011

In this work, poly(methyl methacrylate) (PMMA) was grafted onto amine treated graphite nanosheets ($NH_2$-GNs) and the surface characteristics and physical properties of the $NH_2$-GNs-g-PMMA films were investigated. The graft reaction of $NH_2$-GNs and PMMA was confirmed from the shift of the $N_{1S}$ peak, including amine oxygen and amide oxygen, by X-ray photoelectron spectroscopy (XPS). The surface characteristics of the $NH_2$-GNs-g-PMMA films were measured as a function of the $NH_2$-GN content using the contact angle method. It was revealed that the specific component of the surface free energy (${\gamma}s$) of the films was slightly increased as the $NH_2$-GN content increased. Also, the thermal and mechanical properties of the $NH_2$-GNs-g-PMMA films were enhanced with the addition of $NH_2$-GNs. This can be attributed to the chemical bonding caused by the graft reaction between the $NH_2$-GNs and the PMMA matrix.

• 한국응용과학기술학회지
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• 제18권4호
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• pp.261-272
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• 2001

An ACR/HMMM film was prepared by blending high-solid ACR with curing agent, hexamethoxymethyl melamine (HMMM). An active curing reaction was observed at $170^{\circ}C$. The dynamic viscoelastic $T_{g}$ of the final film increased with the static viscoelastic $T_{g}$ of the film. The log damp value, which means a viscoelastic ratio, decreased with the increase in the curing temperature of the film. Physical properties of the films were within a suitable range for films, and by an accelerated weathering resistance test the films were proved weather resistible ones.

• 한국식품영양과학회지
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• 제27권5호
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• pp.908-913
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• 1998

Chemical components and some physical proeprties of fresh, defrosted and dried yams(Dioscoreab batatas) were determined to obtain basic data for high quality yam processing. Fresh yam showed 81.79% moisture and 15.24% N-free extract. The cohesiveness and adhesiveness of defrosted yam homogenate were significantly higher than those of fresh yam homogenate. Free sugars of yam were mainly composed of sucrose, rhamnose, fructose and glucose, and the contents of fructose and glucose were apparently decreased by hot air drying. Linoleic(45.64%), oleic(8.32%), and arachidic acids(7.40%) were major fatty acids of yam. Hot air drying caused a decrease in unsaturated fatty acids and an increase in saturated acids. Hot air-dried yam powder showed higher gelatinization properties than freeze-dryed yam powder, such asinitial pasting temperature, temperature at maximum viscosity, and viscosity at different parameters. Hot air-dried yam powder showed higher Hunter parameter b and ΔE values and lower L value than freeze-dried one.