• Journal of the Korea Concrete Institute
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• v.27 no.2
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• pp.157-167
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• 2015

Cement composites subjected to high-velocity projectile shows local failure and it can be suppressed by improvement of flexural toughness with reinforcement of fiber. Therefore, researches on impact resistance performance of cement composites are in progress and a number of types of fiber reinforcement are being developed. Since bonding properties of fiber with matrix, specific surface area and numbers of fiber are different by fiber reinforcement type, mechanical properties of fiber reinforced cement composites and improvement of impact resistance performance need to be considered. In this study, improvement of flexural toughness and failure reduction effect by impact of high-velocity projectile have been evaluated according to fiber type by mixing steel fiber, polyamide, nylon and polyethylene which are have different shape and mechanical properties. As results, flexural toughness was improved by redistribution of stress and crack prevention with bridge effect of reinforced fibers, and scabbing by high-velocity impact was suppressed. Since it is possible to decrease scabbing limit thickness from impact energy, thickness can be thinner when it is applied to protection. Scabbing of steel fiber reinforced cement composites was occurred and it was observed that desquamation of partial fragment was suppressed by adhesion between fiber and matrix. Scabbing by high-velocity impact of synthetic fiber reinforced cement composites was decreased by microcrack, impact wave neutralization and energy dispersion with a large number of fibers.

• Journal of Plant Biology
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• v.34 no.1
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• pp.9-18
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• 1991

This study deals with the effect of dwarf growth on xylem structure, especially on the dimension of xylem elements described for 12 species of naturally occuring dwarf trees. The length and tangential diameter of tracheary elements and fibers in dwarf trees appear to be shorter and narrower than those in normal trees. Radial width and cell number of the same annual rings are narrower and smaller in dwarf trees than those in normal trees. Height of rays in dwarf trees is lower than that in normal trees. Dwarf conifers appear to have higher ratio, of latewood to earlywood than that in normal trees. In the hardwood species studied, mesomorphy of vessel elements is lower in dwarfs than that in normal trees. It can be concluded that this dwarf growth occurs as a result of extremely slow growth by environmental stress such as water deficiency.ciency.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.67-67
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• 2019

뽕나무과(Moraceae) 닥나무속(Broussonetia)의 품종에 대한 국내 연구동향으로는 잎의 성상이나 암꽃의 포길이, 엽신의 폭과 같은 수목학 분수학적 관점으로 특징을 파악하기 때문에 구분이 어려운 실정이다. 또한 닥나무(Broussonetia kazinoki Siebold)와 꾸지나무[Broussonetia papyrifera (L.) $L^{\prime}H{\acute{e}}r.$ ex Vent.]의 수목학적 특징이 유사하여 오동정의 사례가 발생하기도 한다. 닥나무의 향명은 다양하게 불리지만 그 분류기준은 명확하지 않다. 본 연구에서는 총 4개 마커(ITS, matK, trnL-F, ndhF)의 염기서열 분석과 분자계통학적 분류를 통해 닥나무와 꾸지나무의 교잡종으로 확인된 전라도지역 닥나무 8개체에 대하여 펄프제지 자원으로써의 특성을 확인하였다. 8개체 인피섬유의 형태학적 특징인 섬유장, 섬유폭, 섬유 내강(Lumen)폭을 통해 Runkel ratio, Slenderness ratio, Flexibility coefficient, Rigidity coefficient를 도출하고 종이의 기계적 강도, 내절도와의 상관관계, 섬유와 섬유간의 결합력 등을 예측하였다. 상기와 같은 연구결과는 유전형질이 동일한 전라도지역 닥나무의 형태학적 특성을 통해 펄프제지 공정에 영향을 미칠 수 있는 인자들을 분석 하였다. 이러한 특성에 따라 다양한 품질의 종이를 제조 할 수 있는 기초 자료로 제공될 것이다.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.3
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• pp.271-279
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• 2018

Previous studies to elucidate the etiology of cyclosporine(Cs)-induced gingival overgrowth in children have not completely excluded all factors that may cause differences among individuals. This study examined the effect of cyclosporine on the metabolism of type 1 collagen(CoL-I) in experimental models that controlled the effects of biological variations on individuals. Five 5-week-old male Sprague-Dawley rats were administered Cs by gastric feeding for 6 weeks. Gingival specimens were harvested from the mandibular posterior area before beginning Cs administration and at 2, 4, and 6 weeks thereafter. Gingival fibroblasts were cultured from all the 20 biopsies collected from the gingiva. Half of the fibroblasts collected prior to the Cs administration were designated as Control. The other half of the fibroblasts were treated with Cs in vitro and called in vitro test group(Tt). The fibroblasts collected 2, 4, and 6 weeks after the Cs administration were called in vivo test groups : T2, T4, T6, respectively. Immunofluorescence microscopy was used to detect CoL-I in all the fibroblasts. CoL-I was analyzed at both the gene and protein expression levels by real-time polymerase chain reaction and western blotting. Changes in CoL-I before and after Cs treatment were evaluated from the gingiva of each rat. There was no significant difference in gene expression of CoL-I in the control and test groups. CoL-I protein expression levels of fibroblasts increased in in vitro Cs treatment for each individual, and also increased in in vivo Cs treatment. In this study, the experimental method that control biological variations that can occur due to differences among individuals was useful. Subsequent studies on other factors besides CoL-I and in-depth studies in humans are needed.

• Journal of Korean Society of Forest Science
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• v.32 no.1
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• pp.73-86
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• 1976

Two individuals ($sp_1$, $sp_2$) of purple and one individual ($sd_1$) of red hearted flower were selected from 18 years old Hibiscus syriacus trees obtained from the seeds treated with colchicine, and their morphological and physiological characteristics were investigated and following results were obtained. 1. The somatic chromosome number of the selected individuals, $sp_1$, $sp_2$, and $sd_1$ were 2n=160, while that of the check tree was 2n=80, indicating that the selected individuals, $sp_1$, $sp_2$ and $sd_1$ were tetraploid. 2. Peroxidase isoenzyme bands of high activity in selected individuals, $sp_1$, $sd_1$ and check tree were mostly in cathode, fixed band was f and v bands, and frequency of each band and their activity were not different between selected individuals, $sp_1$ and $sd_1$ and check tree. 3. The flowers of $sp_1$ individual were large in size and more dark purple than check tree's. The flowers of $sp_2$ individual were not increased in size, but they were dark purple and red heart at the base of the petal was expanded to 2/3 of the petal length. The flower of $sd_1$ individual was also large and some of the red lines from the petal base were extended to 2/3 of the petal length, which was much longer than those of the check tree. 4. Thickess of leaves, length of guard cells, diameter of pollens, wood fiber lengths and woody fiber widths were all increased in $sp_1$, $sp_2$ and $sd_1$ as compared to those of the check tree. 5. Survival percentage of cuttings was 80% with $sp_1$ and 36% with $sd_1$, and their growth performance were inferior to control in their second growing season.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.60-60
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• 2003

릿테르개멍게는 척색동물문 해초강에 속하는 멍게류로서 고착생활을 하며, 보통 해조류나 히드라 등으로 덮여 있어 눈으로 식별하기가 어렵고, 생태 및 분류에 관한 연구만이 있을 뿐이다. 이 연구는 제주도 연안에 서식하는 릿테르개멍게의 번식생태에 대한 기초자료를 얻고자 배우자형성과정 및 생식소 발달 단계 등을 조직학적으로 조사하였다. 실험 재료는 제주도 용담 연안에서 2001년 11월부터 2003년 1월까지 매월 20개체씩 총 300개체를 채집하여 생식소의 조직학적 변화를 관찰하였다. 릿테르개멍게는 자웅동체로서 생식소는 체벽부에 붙어 있고, 성숙시기에 난소는 적색을, 정소는 유백색을 띠고 있다. 생식소와 체벽부를 포함해 절단된 조직표본에서 보면 외측체벽은 근섬유를 포함한 섬유성결합조직이 발달해 있고 여기에 이어진 방형의 난소낭과 그 주변부에 자리 잡고 있는 여러 개의 정소낭을 식별할 수 있었다. 생식소 발달 및 배우자형성과정, 월별 생식소변화를 토대로 생식주기를 구분하면 성장기 (3-5월),난황기 (5-7월), 성숙기 (7-11월), 방출기 (11-2월), 회복기 (1-3월)로 구분되었으며, 주 산란시기는 11-1월로, 연중 1회의 산란시기를 갖는다.

• Journal of Korean Society of Forest Science
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• v.60 no.1
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• pp.45-50
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• 1983

According to the worldwide decreasing tendency in raw materials and increase in wood demands since 1970, the efficient utilization of raw materials was required internationally. Therefore this study dealt with the dimensional characteristics of branchwood fiber of Quercus serrata Thunb for the complete utilization of whole tree. According to the branch individuals, parts and positions within a tree, fiber length, width and wall-thickness were measured. The results obtained are as follows: 1) As the height of individual branchwood increases from ground toward, fiber length and width, and wall-thickness decreased linearly and their regression equations obtained, were Y=770.03-22.643X, Y=27.444-0.71385X and Y=12.308-0.57320X respectively 2) From the main stem to branch in distal direction, fiber length, width and wall-thickness linearly decreased and their regression equations obtained were Y=752.70-0.6724X, Y=26.152-0.0084867X and Y=11.258-0.006205X, respectively. 3) As the radial direction from pith to hark increases, fiber length, width and wall-thickness increased linearly and their regression equations obtained were Y=679.73+11.231X Y=25.382+0.0925X and Y=10.521+0.11787X, respectively. 4) Mean value of fiber length, width and wall-thickness were 625-765, 26 and $11{\mu}m$, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.3
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• pp.99-107
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• 1965

Thirteen varieties of hemp, Cannabinus sativa L., consisting of four Italian, one Japanese and eight local varieties were used in the study on the fiber content and a satisfactory selection for the higher-fiber-yielding plants. In addition, the relationship among fiber contents at the ball setting stage, and at the maturity stage, primary fiber content, and total fiber content were determined. The results of the study are summarized as follow: 1. Fiber weight of the matured male plant expressed as percentage of the fiber weight to dried stems varied from 12.09 to 26.71 percent for the Italian varieties, 14.25% for the Japanese variety and ranged from 6.59 to 16.79 for the local varieties. It was shown that on the average, Italian varieties contained more fiber compared with the other varieties. 2. On the same basis, the average percent age of fiber for Italian male plants was 20.77 while it was 20.96 for female plants. For the Japanese variety, similar figures were 14.24 for male plants and 15.43 for female plants. By comparison, the average percent fiber for the male plants of Korean varieties was only 10.34 but averaged 16.79 for female plants. In this experiment, female plants contained a greater percentage of fiber than male plants. 3. Statistically significant correlations were obtained between fiber content at the ball setting stage and fiber content of the mature plant. The correlation coefficient was r=0.942＊＊, while the regression equation was Y=0.28+1.03X. These data indicate that plant. selection by early testing at the ball setting stage is an effective method for the improvement of fiber content. 4. The correlation between primary fiber content and total fiber content was r=0.913＊＊, with a regression equation of Y=12.01+1.20X. It should thus be possible to obtain plants of higher total fiber content at maturity by the selection of plants which have a higher content of primary fiber at the ball setting stage. 5. From a study of the transverse sections from the hemp plant it was shown that Italian varieties have wide bands of primary and secondary fibers with narrow areas of woody material, while both Korean local varieties and Japanese varieties have narrow bands of primary and secondary fiber and wide areas of woody material. For hemp improvement, it is certain that a variety which has a narrow area of woody substances and wide area of fiber in its stem should be selected.

• Applied Microscopy
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• v.30 no.2
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• pp.213-232
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• 2000

The development of the knee joint was studied by electron microscopy in human fetuses ranging from 20 mm to 260 mm crown-rump length ($7\sim30$ weeks of gestational age). The appearance of the primordium of the meniscus and cruciate ligament was conspicuous as the mesenchymal cells , preceeding that of joint space at 30 mm fetus. The primitive joint cavity was first seen in the interzone from the 40 mm fetus and its intermediate layer proceeded developing as a narrow cleft which was closely incorporated with two chondrogenic layers. Poorly differentiated mesenchymal cells of the meniscus at 40 mm fetus containing predominantly free ribosomes differentiated into fibroblasts at 60 mm fetus. By 100 mm fetus, the fibroblast in inner zone of the meniscus presented as oval profiles with a short cell processes, whereas middle and peripheral zones presented as elongated cells. Differentiation of the synovial membrane coincided with clarification of the joint cavity When dilatation of the synovial cavity occurred, the two types of synovial cells were identified at 60 mm fetus. By 100 mm fetus a majority of the intimal cells were B-type. B-type cells were clearly distinguishable from A-type cells by their content of extensive rough endoplasmic reticula and well developed Golgi complexes. In contrast, A-type cells had numerous filopodia, pinocytotic vesicles, lysosomes and large vacuoles. At 260 mm fetus the B-type cells were also a majority of intimal cells. At 260 mm fetus the inner zone of the meniscus was filled with parallel oriented fascicles of collagenous fibers and oval fibroblasts. The middle zone was constituted of parallel and radially arranged fibers and fibroblasts. The outer zone was populated by elongated fibroblasts encircled by crossed collagenous fibers with the blood vessels. At 30 mm fetus the fibroblasts of the cruciate ligament contained rough endoplasmic reticula and mitochondria. Collagen fibrils were noted within narrow cytoplasmic processes which were continued with the extracellular space. Collagen fibrils of ligament were filled in the bulk of extracellular space at 100 mm fetus. By $150\sim260mm$ fetus, the cruciate ligaments were constituted of longitudinally oriented bundle of collagen fibrils with irregular rows of round cells between.

• KOREAN POULTRY JOURNAL
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• v.4 no.6 s.32
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• pp.85-87
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• 1972

결과적으로 시판 피마자박을 성장하는 병아리 혹은 기타 단위 동물의 단백질 사료로서 이용하기위해서는 다시 제독처리해야함을 알 수 있다. 제독처리 방법 중에서도 끓는 물로 여과하여 독소를 축출하는 방법이 가장 좋고 이 방법이 독소를 전부는 아닐지라도 대부분 제거시키는 방법이다. 피마자박의 아미노산조성을 볼때 그 생물가가 낮은 주요 원인이 라이신 트립토판 그리고 S 함유 아미노산이 부족하기 때문임을 알 수 있다. 제독처리한 피마자박의 라이신과 메치오닌 그리고 트립토판을 첨가하면 대두단백+메치오닌(0.2$\%$) 만큼 병아리성장에 유효함을 알 수 있다. 다른 필수 아미노산의 첨가는 별 효과가 없고 어분 대두단백 혹은 난백의 첨가도 부족한 아미노산을 첨가해 주는 것만큼 효과적이 아니었다. 라이신이 가장 먼저 부족되는 것이고 다음 트립토판이다. 메치오닌은 NRC 권장량의 60$\%$ 밖에 안되나 실제로 피마자박에 적절히 함유한다. 이것은 NRC 권장량이 너무 높다는 스콧트와 그의 동료의 주장과 일치하고 있다. 체중변화를 볼 때 흥미있는 것은 피마자박에 어분을 첨가하면 각 그룹간 병아리 체중의 차이가 심한데 어분대신 아미노산을 첨가하면 그 차이가 현저히 감소한다. (25$\%$와 15$\%$) 이러한 현상은 아미노산이 부족한 사료를 먹으면 성장에 필요한 아미노산 요구량이 개체별로 차이가 있기 때문일 것이다. 피마자박에 아미노산을 첨가하면 단백질 최종이용율이 현저히 증가하나, 이정도는 대두단백+메치오닌(0.2$\%$)에 비하면 이용율이 낮은데 그 이유는 아마 피마자박중의 리그닌과 조섬유 함량이 높기 때문일 것이다. 피마자박의 사료는(사료중 40$\%$) 조섬유가 약 15$\%$나 되어 이것 때문에 사료 섭취량이 대두단백사료 보다 증가하게 되고 사료섭취량이 많으면 단백질 섭취도 많게 되어 피마자박의 단백질 이용율이 낮게 된다. 즉 최종 단백질 이용율은 단백질 섭취량과 역비례한다. 만약 피마자박의 조섬유를 일부 혹은 전부 제거하기만 한다면 양계및 기타 단위 동물의 단백질 사료 자원으로서 그 가치가 훨씬 높아질 것이다. 더욱 희망적인 것은 피마자박 생산자측에 의하면 피마자씨 껍질의 상당한 부분을 제거하는 것은 가능하다고 한다.