• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.722-731
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• 2020

The purpose of this research is to determine the efficiency of impregnation using phenol formaldehyde resin to enhance Falcataria wood's stability and better mechanical properties. Impregnation process was carried out after moisture content stabilized at 12% on samples with a dimension of 20 mm × 20 mm × 300 mm at various concentrations and pressure time. Dimensional stability was evaluated by thickness swelling (TS) and anti-swelling efficiency (ASE) and the young's modulus was conducted according to BS 573. The mechanical properties and dimensional stability of impregnated wood were evaluated. Dimensional stability and mechanical properties of Falcataria wood were successfully increased after impregnation. PF impregnation can improve the mechanical properties and the density from 0.26 g/㎤ to 0.30 g/㎤ even with only 10% of weight percent grain. Dimensional stability increases with increasing resin concentration and time pressure. The highest increase in mechanical properties was found at a higher concentration of PF. The penetration of PF into the wood's cell darkens the color of impregnated wood.

• Journal of the Korean Wood Science and Technology
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• 제18권3호
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• pp.26-33
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• 1990

To study the wood quality factors of Populus nigra $\times$ maxmowiczii known a rapidly growing species, the variations of green moisture contents, bulk density, wood fibre dimensions, microfibril angles, and number of leaf knot in stem wood were investigated. The heartwood contained a higher moisture content than the corresponding sapwood. Bulk density in radial patterns variations decrease outward from the pith, then increase toward the bark. The wood-fiber length and diameters had somewhat smaller values than on Populus alba $\times$ glandulosa or Populus euramericana. The microfibril angles decreased rapidly toward the outside, and their mean values were about 16 degree. The grain angles run nearly parallel to the cell axies. Number of leaf knot showed a fluctural change above ground level to a point near the base of the crown and then increased rapidly to the top of tree and average number of leaf knot varied exclusively from tree to tree.

• 대한원격탐사학회지
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• 제33권4호
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• pp.411-422
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• 2017

This research aims to analyze spectral reflectance of intertidal zone and its changes under various environmental conditions. We sampled sand of Mongsanpo tidal flat, Korea, and measured its spectral reflectance by using a spectroradiometer under various water contents, compositions and granularity. We also simulated the reflectance of Landsat 7 ETM+ and compared it with an actual satellite data. Five locations were selected for sampling from the coastline towards the ocean. Grain size diminished stepwise from the coastline to ocean direction, while spectral reflectance differed with wavelength. Water contents lowered the overall reflectance especially at the water absorption bands. Spectral reflectance data were then converted into the simulated one by using Landsat 7 ETM+ spectral reflectance function to be compared with the actual Landsat 7 ETM+ images. It showed the decrease of the spectral reflectance due to the increase of moisture contents from seashore towards the ocean. It is shown that Landsat 7 ETM+ imagery can be efficient to extract moisture contents in the tidal flat while compositional analysis needs satellite sensors with much higher spectral resolution.

• Journal of the Korean Wood Science and Technology
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• 제26권1호
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• pp.38-50
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• 1998

Laser cutting tests were conducted to investigate the laser cutting characteristics of solid woods such as 25mm-thick white oak(Quercus acutissima) and maple(Acer mono), and wood-based panels such as 15mm-thick medium density fiberboard and particleboard. Test variables were laser power, cutting speed, grain direction, and moisture content. Specific cutting energy was measured and the qualities of cut surface were estimated in constant laser power. Specific cutting energy of white oak was larger than that of maple, and specific cutting energy of medium density fiberboard was smaller than that of particleboard. For both white oak and maple, specific cutting energy of green wood was smaller than that of air-dried wood because weight loss of moisture evaporation in green wood was larger than that in air-dried wood. In laser-cut surface, wood cells were not deformed and damaged, but in circular saw-cut surface fibers were pushed out and cut, and wood cells were deformed severely. However, mechanical surface roughness of saw-cut surface was smoother than that of laser-cut surface because of the existence of undeformed cell cavity in laser-cut surface.

• 한국작물학회지
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• 제15권
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• pp.69-75
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• 1974

1. 질소시비를 하지않은 콩에서 개화기이후의 토양수분부족은 충분한 생육을 한 콩보다 생육일수가 3-4일 단축되었다. 2. 엽면적은 발아후 40일경까지는 처리의 영향이 컸다. 3. 경장 경경 분지수 분지장은 파종후 70일경에 거이 완성되었고 초기생육이 불량한 경우 가장 떨어졌다. 4. 질소 증시가 협수를 증가시키지 못했고 개화기의 토양수분부족은 협수를 심히 감소시켰고 이러한 콩은 분지협보다 주경협이 많았으며 또 다입협율이 높았다. 5. 주경절입별 착입수는 3-4절과 10-12절에 많았다. 3-4절에는 충분한 생육을 한 콩에서 많았고 10-12절에는 빈약한 생육을 한 콩에서 많았다. 6. 1주입수가 적은콩이 백입중은 높았다. 7. 단백질함량은 백입중이 낮은콩(N$_{0}$D$_4$)에서 가장 낮았고 유지는 1주입수가 적은콩에서 낮았다.

• 한국식품영양학회:학술대회논문집
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• 한국식품영양학회 2001년도 동계 학술심포지움
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• pp.39-74
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• 2001

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s∼1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great, progress and success was obtained in development of high-quality japonica cultivars and qualify evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice caltivars and special rices adaptable for food processing such as large kernel, chalky endosperm aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and torture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak. hot paste and consistency viscosities of viscogram with year difference. The high-quality rice variety “Ilpumbyeo” showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic mcroscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high Probability of determination. The ${\alpha}$ -amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were Ilpumbyeo, Chucheongbyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tongil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, shelved the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogiadation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice bread. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large gram rices showed better suitability for fermentation and brewing. Our breeding efforts on rice quality improvement for the future should focus on enhancement of palatability of cooked rice and marketing qualify as well as the diversification in morphological and physicochemical characteristics of rice grain for various value-added rice food processings.

• 한국농공학회지
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• 제27권2호
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• pp.57-71
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• 1985

The characteristics of compaction and unconfined compressive strength were investigated by mixing with lime to all soils adjusted by given percentages of two kinds of clays to sand to obtain the most effective distribution of grain size and the optimum lime content for soil stabilization. In addition, unconfined compressive strength and durability tested by adding of sodium metasilicate, sodium sulfate, sodium carbonate, sodium gydroxide and magnesium oxide to lime-soil mixture mixed with 8 percent lime to adjusted soil having the mixing percentage of 60 percent of cohesive black clay and 40 percent of sand by weight to get the effect and the optimum content of chemicals. The results obtained were as follows; 1.With the addition of more lime, the optimum moisture content was increased, and the maximum dry density was decreased, whereas the more the amount of clay and the less was the maximum drt density. 2. In the soil having more fine grain size the unconfined compressive strength was larger in the earlier stage of curing period, in accordance with the longer period, the mixing percentages of sand to clay showing the maximum unconfined compressive strength, on the basis of 28-day strength, were 60% : 40% (black clay) and 40% : 60% (brown clay) respectively. 3. The reason why the soil adjusted with black clay was remarkably bigger in the unconfined compressive strength than ones adjusted with brown clay for all specimen of lime-soil mixture was the difference in the kind of clay, the amount of chemical compositions the value of pH. Black clay was mainly composed of halloysite that reacted with lime satisfactorily, whereas the main composition of brown clay was kaolinite that was less effect in the enhance of unconfined compressive strength. Also the difference of unconfined compressive strength was because black clay was larger in the amount of composition of calcium oxide and magnesium oxide in the value of pH affecting directly on the unconfined compressive strength of lime-soil mixture than brown clay. 4. In the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40%, on the standard of 7-day strength, the effect of chemical was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium hydroxide and sodium metasilicate. 5. The optimum amount of chemical being applicable to the maximum unconfined compressive strength of lime-chemical-soil mixture was 1 percent by weight for air dry soil in the case of adding sodium carbonated and 0.75 percent on sodium hydroxide, the unconfined compressive strength was increased continuously with increase of the amount of chemical up to 2 percent of chemical content is the lime-chemical-soil mixture added sodium metasilicate, sodium sulfate and magnesium oxide. 6. It was considered that the chemical played and accelerant role of early revelation of strength because the rate of increase of unconfined compressive strength of all of lime-chemical-soil mixtures was largest on the 7-day cured specimen. 7. The effect of test on freezing and thawing after adding suitable amount of chemical on the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40% was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium metasilicate and sodium hydroxide.

• 한국작물학회지
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• 제27권1호
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• pp.1-10
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• 1982

주요 수도품종들의 탈립성 정도와 곡립의 인장강도와 탈립성 및 수확작업시 포장손실과의 관계를 밝히므로서 탈립성에 관한 품종개량 및 포장손실의 최소화에 도움을 주고자 본 연구를 수행하였다. 11개 품종을 공시 공시했으며 출수 후 35일부터 63일까지의 기간에 1주일 간격으로 품종 및 수확기 별로 임의 추출한 10이삭 200립씩에 대한 곡립의 인장강도, 탈립정도 및 수분함량을 측정했으며, 탈립정도는 이삭을 수확직후 1.5m 지상에서 콘크리트바닥에 낙하시켰을 때 탈립되는 곡립수의 전곡립수에 대한 비율이었다. 또한 포장손실과 곡립의 인장강도와의 관계는 농가포장에서 2품종을 선정하여 출수 후 40일부터 1주일 간격으로 3-4회 binder harvester를 실제 사용하여 포장에 탈립된 량을 측정하고 이를 같은 재료에 대해 측정한 곡립의 인장강도와 관계를 지었으며 3반복하였다. 그 주요결과는 다음과 같이 요약된다. 1. 공시품종들의 평균 곡립인장강도는 90g(밀양 2003) 정도부터 250g(진흥) 정도까지의 범위에서 품종 및 수확기에 따라 차이가 있었으며, 그 표준편차는 30-60g 정도이었는데 곡립의 평균 인장강도가 큰 품종일수록 편차가 컸다. 2. 낙하검정에 의한 곡립의 탈립정도는 밀양2003 20-30%, 수원 29004 3-16%, 한강찰 13-15%, 이리 348호 1-21%, 금강 및 태백 1% 정도로서 수확기에 따라 다소간 차이를 보였다. 3. 낙하검정에서 탈립하기 시작하는 평균 인장강도는 180g이었고, 공시이삭들의 곡립들 중 인장강도가 98g 이상인 것들은 탈립하지 않았으며 인장강도가 10g 저하하면 탈립율은 3-5% 증가했다. 4. 낙동벼와 이리 348호는 수확기가 늦어지면 곡립의 인장강도가 작아지었지만 그밖의 품종들에서는 반대로 인장강도가 다소간 커지거나 별로 변화하지 않았으며, 탈립율도 이리 348호를 제외하면 수확기의 영향을 크게 받지 않았고, 곡립의 인장강도는 수분함량과 대체로 역상관관계를 보였다. 5. 곡립의 평균 인장강도와 binder 수확시의 포장손실량과는 부의 상관이 있었으며, binder 수확시 포장손실이 일어나지 않게 되는 한계 평균인장강도는 174g이었으며 그 이하에서 평균인장강도가 10g 저하되면 포장손실은 ha당 40kg 정도 증가하였다. 6. 현재 품종들의 탈립성 분류기준으로 사용되고 있는 평균인장강도는 그 분산이 변이가 크고, 환경의 영향을 많이 받으며 이삭의 곡립들 중 수확작업시 실제로 탈립이 잘 되는 곡립은 인장강도가 98g이하이었으므로 품종의 탈립성 판정 및 포장손실의 추정을 위해서는 표본중 인장강도가 100g 이하인 곡립들의 전곡립수에 대한 비율을 기준으로 할 것을 제의한다.

• 한국작물학회지
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• 제59권4호
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• pp.445-456
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• 2014

본 연구에서는 단옥수수 주요 품종인 고당옥과 구슬옥을 재배하여 고품질 단옥수수 생산 재배법을 보급하기 위한 기초자료를 제공하고자 종실의 등숙 중 이화학적 특성 변화를 조사하였다. 파종시기와 관계없이 등숙이 진행됨에 따라 수분 함량은 감소하고, 종실 100립의 생중과 건중은 증가하였고(p<0.05), 파종시기가 늦어질수록 100립중의 증가 속도는 느려졌다. 종실의 조단백과 조회분 함량은 출사 후 일수가 경과함에 따라 감소하는 경향을 보였고, 조지방 함량은 유의하게 증가하였다(p<0.05). 단옥수수 종실의 총 유리당 함량은 파종시기와 관계없이 출사 후 일수가 경과함에 따라 유의하게 감소하였으나(p<0.05), 유리당을 구성하는 fructose, glucose, sucrose와 maltose의 조성은 파종시기에 따라 차이를 보였으며 그 중 sucrose가 대부분을 차지하고 있었다. 종실의 전분 함량과 경도는 출사 후 일수가 경과함에 따라 유의하게 증가하는 경향을 보였으며(p<0.05), 전분 함량의 증가 속도 역시 100립중과 마찬가지로 파종이 늦어질수록 느려지는 경향을 보였다. 수확 적기의 종실 수분함량은 68~69% 정도였으며, 전분 함량은 7월 10일 파종이 가장 높았고 7월 30일 파종이 가장 낮았다. 적기에 수확한 단옥수수의 단맛을 비교한 결과 고당옥은 4월 10일 파종한 것에 비해 7월 20일, 7월 30일 파종이 약 1.8배와 1.4배 단맛이 높은 반면 구슬옥은 파종시기와 상관없이 단맛의 정도가 비슷하였다.

• 한국식품과학회지
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• 제29권5호
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• pp.963-968
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• 1997

쌀밥에 곡류나 두류를 적당히 혼합하면 쌀에 부족된 영양적인면을 보완할 수 있으나 혼합취반에 따른 번거로움 때문에 쉽게 일상화되지 못하고 있는 실정을 감안하여 현미, 보리, 밀, 조, 수수, 콩, 팥 등의 원료를 일차 분쇄하고 혼합한 후 쌍축압출성형기를 사용하여 쌀알 형태로 성형하였다. 원료의 기본배합비를 현미 30%, 보리 30%, 밀 20%, 조 5%, 수수 5%, 콩 7%, 팥 3%로 결정하였으며 원료의 배합비율에 따른 압출성형조건으로 스크류 속도는 250 rpm, 가수율은 $24{\sim}30%$, 배럴온도는 $50{\sim}60^{\circ}C$로 설정하여 성형물의 팽화를 억제함과 동시에 $5{\times}0.8mm$ 직사각형의 토출구를 사용하고 절단칼의 회전속도 등을 조절하여 재성형 혼합곡을 성공적으로 제조하였다. 재성형 혼합곡립의 크기와 형태는 단립종 백미와 유사하였고 체적은 백미에 비해 약간 높았으며 침지에 의한 수화속도가 빨라 수분흡수율이 높게 나타났다. 취반 후 혼합곡립의 경도는 백미에 비해 약간 낮았고 부착성은 높았다. 압출성형기법을 이용하여 제조한 재성형 혼합곡은 쌀밥에 영양성, 간편성, 기호성을 보충시킬 수 있는 주식개념의 혼합곡으로서의 가치가 매우 큰 것으로 판단되었다.