• 한국광학회지
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• 제13권3호
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• pp.235-239
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• 2002

본 논문에서는 고리구조 FBG공동과 DFB 레이저를 결합하여 kHz대의 극미세선폭 레이저광을 발생시키는 새로운 방법을 제안하였다. 외부 FBG와 DFB 레이저내의 Bragg격자로 이루어진 긴 공동내에 고리구조를 형성함으로써 레이저 선폭을 압축시키는 방법을 사용하였다. 손실을 최대화하면서 모드홉핑이 일어나지 않는 최대 광궤환량을 유지하기 위하여 광회전기와 가변광감쇄기를 사용하였다. 이 방법의 타당성을 검증하기 위하여 63km의 광섬유 지연선로를 사용한 자기헤테로다인 측정장치를 사용하여 레이저 선폭을 측정한 결과 자기헤테로다인 측정장치의 해상도 한계인 3kHz 이하의 선폭을 얻었다. 이는 2$\times$$10^{-8}$ nm의 선폭에 해당한다

• 한국염색가공학회지
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• 제19권5호
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• pp.37-40
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• 2007

The electrostatic layer-by-layer technique provides a convenient way to control the construction of ultrathin films at nano-scale ranges and can be easily obtained. It can be also applicable to fiber substrate with dye compounds. We have fabricated multilayer dye films using diazonium resin and three couplers, which are prepared by self-assembly approach. This method is based on layer-by-layer deposition using electrostatic attraction between oppositely charged ions. Beside, the diazo coupling reaction proceeded to form azo dye layer on the PET fibers the same time. The corresponding results of the multilayer films have been discussed on the level of color strength (K/S).

• 동아시아식생활학회지
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• 제17권3호
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• pp.329-337
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• 2007

In this study, the interest of female high school students's(N=500) for weight control, as well as nutrient intake status, were analyzed. The mean age, height, and weight of the subjects were, 19.3 years, 162.2 cm and 55.4 kg respectively. Mean BMI was $21.1 kg/m^2$. According to BMI, the percentage of underweight, normal weight, overweight, and obese were 18.5 %, 60.3%, 11.3%, and 11.3% respectively. By the BMI criteria, 60.3% of the subjects were normal weight while the rate of self-recognition was 41.5%. The degree of satisfaction regarding self-body image was only 17.1% and 60.9% showed an interest in weight control. The reason for weight reduction were appearance(65.1 %) and health(24.2%). The body areas where subjects wanted to lose weight included the thighs(32.9%) and whole body(29.3%). They believed the most effective weight control strategy was exercise(81.1 %) and the strategies they used were diet(59.1 %) and exercise(40.4%). Energy intake was 1,733.4 kcal which was 86.7% of the estimated energy requirements(EER). Calcium, vitamin $B_2$, and vitamin C intakes were less than EAR by 34.4%, 40.4%, and 59.6% respectively. The intake of dietary fiber was 5.1 g only 21.1 % of the adequate intake(AI). In summary, high school females interested in weight control have significantly less calcium intake than their peers. The correlations between interest in weight control and weight and BMI were significant(p<0.001). The results of this study suggest that to achieve optimal growth, improved diets that include calcium, vitamin $B_2$, and vitamin C are recommended. High school females interested in weight control should especially be targeted for education on calcium intake.

• 동아시아식생활학회지
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• 제17권1호
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• pp.11-19
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• 2007

This study was designed to evaluate Saturday nutrition classes for obese elementary students in Chungnam Province. Obesity index, nutrient intake, nutrition knowledge, nutrition attitude, and self-satisfaction of 36 obese elementary students were compared before and after attending nutrition classes every other Saturday for 3 months. The average age, height, weight, body fat, % body fat, and obesity index were 11.9 years, 145.5 cm, 53.3 kg, 24.5 kg, 45.7%, and 32.4%, respectively. Most of the subjects(94.5%) viewed themselves as fat. Sixty-three percent of children were discontent with their body-image. All answered that they have experience with weight control. The major methods of weight control were exercise and reduction of snacks. The mean serum cholesterol, blood glucose, GOT/GPT, and hemoglobin were 177.4 mg/dL, 90.4 mg/dL, 25.8/25.5 IU/L, 14.5 g/dL, respectively. After attending nutrition classes, the daily intakes of energy, plant protein, plant fat, carbohydrate, crude fiber, and cholesterol increased significantly. The scores for nutrition knowledge, nutrition attitude, and self-satisfaction also increased after nutrition classes, but there were no significant differences. Percent body fat decreased significantly after nutrition classes. In conclusion, nutrition education for elementary students is effective for the prevention and control of obesity. Further research is needed to develop a systematic program of nutrition education for obese children.

• 자원리싸이클링
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• 제29권2호
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• pp.8-17
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• 2020

본 연구에서는 분쇄 가공된 폐닥나무의 친환경 조습 제품에 대한 적용 가능성을 확인하기 위해 인피섬유와 폐닥나무 분쇄 펠렛의 흡·방습 성능 측정을 진행하였다. 폐닥나무 분말은 710-355㎛, 355-100㎛, 100-45㎛ 및 45㎛ 미만의 입도별로 분류하여 사용하였다. 분말의 비표면적은 입자 크기가 710㎛부터 45㎛미만으로 감소할수록 1.02㎡/g에서 1.35㎡/g로 증가하는 경향을 나타내었다. 흡·방습량은 355-100㎛, 710-355㎛, 100-45㎛, 45㎛미만 및 인피섬유의 순으로 감소하였으며, 각각 141.1g/㎡, 147.1g/㎡, 135.7g/㎡, 129g/㎡의 흡습 및 117.2g/㎡, 123.6g/㎡, 110.2g/㎡, 93.3g/㎡의 방습 성능이 확인되었다. 폐닥나무 분말의 흡습 및 방습 성능은 닥나무 인피섬유 보다 우수하였으며, 이는 펠렛 내부 기공의 분포와 섬유 손상에 기인한 것으로 사료되었다.

• Advances in nano research
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• 제15권6호
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• pp.495-511
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• 2023

In this research, the impact of micro-silica, nano-silica, and polypropylene fibers on the fracture energy of self-compacting concrete was thoroughly examined. Enhancing the fracture energy is very important to increase the crack propagation resistance. The study focused on evaluating the self-compacting properties of the concrete through various tests, including J-ring, V-funnel, slump flow, and T50 tests. Additionally, the mechanical properties of the concrete, such as compressive and tensile strengths, modulus of elasticity, and fracture parameters were investigated on hardened specimens after 28 days. The results demonstrated that the incorporation of micro-silica and nano-silica not only decreased the rheological aspects of self-compacting concrete but also significantly enhanced its mechanical properties, particularly the compressive strength. On the other hand, the inclusion of polypropylene fibers had a positive impact on fracture parameters, tensile strength, and flexural strength of the specimens. Utilizing the response surface method, the relationship between micro-silica, nano-silica, and fibers was established. The optimal combination for achieving the highest compressive strength was found to be 5% micro-silica, 0.75% nano-silica, and 0.1% fibers. Furthermore, for obtaining the best mixture with superior tensile strength, flexural strength, modulus of elasticity, and fracture energy, the ideal proportion was determined as 5% micro-silica, 0.75% nano-silica, and 0.15% fibers. Compared to the control mixture, the aforementioned parameters showed significant improvements of 26.3%, 30.3%, 34.3%, and 34.3%, respectively. In order to accurately model the tensile cracking of concrete, the authors used softening curves derived from an inverse algorithm proposed by them. This method allowed for a precise and detailed analysis of the concrete under tensile stress. This study explores the effects of micro-silica, nano-silica, and polypropylene fibers on self-compacting concrete and shows their influences on the fracture energy and various mechanical properties of the concrete. The results offer valuable insights for optimizing the concrete mix to achieve desired strength and performance characteristics.

• 자원리싸이클링
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• 제30권4호
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• pp.35-45
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• 2021

본 연구에서는 폐닥나무 섬유를 사용한 목모보드의 제조 및 조습 특성 분석을 수행하였다. 목모보드 제조를 위해 폐닥나무 섬유의 분쇄 시간을 30, 60, 120, 180초로 제어하였으며, 혼합량을 시멘트 대비 0, 3, 6, 9% 수준으로 외할 첨가하여 제어하였다. 분쇄시간 제어 조습섬유 혼입 목모보드의 흡·방습 특성 분석 결과, 60초 분쇄 섬유 혼합 목모보드가 흡·방습 성능이 뛰어난 것으로 확인되었으며, 이는 분쇄 섬유의 손상이 적어 소재 자체의 흡·방습 성능이 보드 혼합 시에도 발현되었기 때문이다. 또한 섬유 혼합량 제어 목모보드의 흡·방습 특성 분석 결과, 6% 혼합 목모보드가 흡·방습 특성이 가장 뛰어났으며, 흡습 및 방습량은 각각 291.00g/m² 및 108.75g/m²으로 확인되었다.

• Composites Research
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• 제20권2호
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• pp.21-26
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• 2007

이 논문은 합성섬유를 이용하여 포틀랜드 시멘트 모르타르를 보강한 복합재료인 ECC(Engineered Cementitious Composite)의 설계 과정과 건설현장에 이 복합재료를 적용할 수 있도록 시공성을 부여한 연구 내용을 정리하였다. 이 연구에서는 다양한 시공성, 즉 자기충전(self·consolidating)과 스프레이 시공성을 갖는 ECC를 제작하기 위하여 단계적인 재료 개발 방법론을 채택하였다. 우선 마이크로역학(micromechanics)과 안정상태균열이론(steady-state cracking theory)을 이용하여 골재와 섬유를 선정한 후, 굳기 전 재료의 레올로지를 제어하는 방법으로 시공성을 구현하였다. 여기서, 굳기 전 재료의 레올로지를 제어하기 위하여 화학첨가제(chemical admixtures)와 광물첨가재(mineral admixtures)의 양을 소량으로 조절하는 방법을 사용하였다. 이러한 방법을 활용함으로써 굳기 전에는 다양한 시공성을 나타내면서, 굳은 후에는 높은 연성(인장변형경화 거동)을 나타내는 실용적인 ECC 복합재료를 개발하였다.

• Computers and Concrete
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• 제19권4호
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• pp.339-346
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• 2017

The main objective of this paper was to illuminate the effect of marine environmental condition on durability of reinforced concrete (RC)-corroded columns strengthened with carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) layers. Small-scale columns were prepared and corroded by an accelerated corrosion process. After strengthening, compressive strength tests were carried out on control and weathered specimens. In this research, a marine simulator was designed and constructed similar to the tidal zone of marine environment in south of Iran which was selected as a case study in this research. Mechanical properties of wrapped specimens were studied after placing them inside the simulator for 3000 hours. Marine environment decreased ultimate strength by 4.5% and 26.3% in CFRP and GFRP-wrapped columns, respectively. In some corroded-columns, strengthening was carried out after replacing damaged cover by self-compacted mortar. In this method, by confining with one layer of CFRP and GFRP, 4.2% and 22.4% reduction in ultimate strength was observed, respectively, after exposure. Furthermore, the elastic-brittle behavior has been verified in this retrofit method. Also results of tension tests revealed, the ultimate tensile strength was degraded by 2% and 28.8% in CFRP and GFRP sheets, respectively, after applying marine exposure.

• 대한지역사회영양학회지
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• 제16권1호
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• pp.155-168
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• 2011

This study was conducted to assess needs of self-management nutrition program for diabetic patients. The survey was conducted among 100 diabetic patients, and the mean age of the subjects was 54.2 years old. Thirty three percent of the subjects were diagnosed diabetes less than 2 years ago. The average nutrition knowledge score about diabetes was 10.2 point, and percentages of correct answers were very high in 'foods rich in fiber' (97.0%), 'relevance of exercise and insulin' (97.0%), 'quantity of insulin injection' (91.0%), and 'diabetes menu' (91.0%). The sources of nutrition information were hospitals/healthcare centers (56.1%), TV/radio (19.2%), and internet (13.1%). Sixty nine percent of the subjects have experienced nutrition education on subjects as 'menu planning skills'(22.4%), 'selecting foods' (22.4%), 'relevance of blood glucose and eating foods' (21.5%) by personal counseling (54.4%). The total score of eating behavior was higher after diagnosed diabetes (35.3) than before (30.0) (p < 0.001). The preferred topics in developing diabetes nutrition information websites were 'diabetes mellitus', 'relevance of blood glucose and foods', and 'selecting foods for diabetes'. The subjects wanted the websites developed by 'using mainly illustrations, pictures, tables' (22.8%) and 'using simple design' (19.6%). The preferred contents in developing diabetes self-management nutrition program were 'dietary life diagnosis', 'chronic disease risk diagnosis', 'calorie control by selecting foods and cooking skills', and 'dietary assessment'. In designing the program, the subjects' most wanted designs were 'be handy and simple in using' (29.3%), 'using simple design' (17.9%), and 'using mainly illustrations, pictures, tables' (15.7%).