• 한국건설순환자원학회논문집
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• 제8권1호
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• pp.33-40
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• 2013

최근 시멘트 생산 시에 발생하는 다량의 $CO_2$로 인한 환경문제가 심각한 실정이며, 이러한 환경문제를 해결하기 위해 고로슬래그 미분말과 같은 산업부산물을 시멘트 대체 재료로 사용한 알칼리 활성 슬래그 콘크리트에 대한 연구가 활발히 진행되고 있다. AAS 콘크리트는 상온에서 고강도 발현이 가능하지만 알칼리 반응으로 인한 빠른 응결시간과 유동성 손실로 인해 작업시간 확보에 어려움이 있는 것으로 알려져 있다. 본 연구에서는 알칼리 활성 콘크리트의 구조 부재 적용을 위한 기초 자료 확보를 위해 AAS 모르타르의 압축강도 및 유동 특성에 시멘트용 유동화제가 미치는 영향을 분석하였다. 물-결합재비(W/B)는 0.35로 고정하고 알칼리 활성화제로 수산화나트륨과 물유리를 사용하여 AAS 모르타르를 제조하였으며, 유동성 확보를 위해 4종의 유동화제인 나프탈렌(N), 리그닌(L), 멜라민(M), PC(P) 계를 각각 슬래그 질량대비 최대 2%까지 첨가하여 압축강도, 플로우, 초음파 속도를 측정하였다. 실험결과, 멜라민계 유동화제를 첨가한 경우 AAS 모르타르의 압축 강도 저하 현상 없이 유동성이 증진되는 것으로 나타났으며, 나프탈렌계와 PC계의 경우에는 유동성 개선효과가 미미한 것으로 나타났다.

• Tuberculosis and Respiratory Diseases
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• 제38권4호
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• pp.340-346
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• 1991

Tuberculous tracheobronchitis is defined as a specific inflammation of the trachea or major bronchi caused by the tubercle bacillus and recognized as one of the most common and serious complication of pulmonary tuberculosis. It had been a diagnostic challenge in prebronchoscopic era and since 1968, fiberoptic bronchoscopy has been accepted as a safe and valuable diagnostic procedure of tuberculous tracheobronchitis. Now, it remains a troublesome therapeutic problem due to its sequelae such as bronchostenosis, bronchiectasis and bronchial deformity. The authors analyzed the clinical features, radiological findings and bronchoscopic findings with pathologic and bacteriologic study on 61 cases of tuberculous tracheobronchitis and following results were obtained. 1) The peak incidence was in the fourth decade and male to female ratio was 1:3.4. 2) The most common symptom was cough (86.9%) and followed by sputum (49.2%), dyspnea (27.9%), fever (19.8%), weight loss (11.5%), hemoptysis (6.6%), hoarseness (6.6%) and chest discomfort (3.3%) and localized wheezing was heard in 18%. 3) In chest X-ray, consolidation with collapse was observed in 70.5%, and followed by consolidation only (18.0%), mediastinal node enlargement (8.2%), cavitary lesion (6.6%), suspicious hilar mass (3.3%) and miliary lesion (1.6%) and there was no abnormal findings in 4.9%. 4) Bronchoscopy showed hyperplastic lesion in 67.2%, mucosal lesion (18.0%), ulcerative lesion (9.8%) and stenotic lesion (4.9%). The most common site of bronchial lesion was right upper bronchus (36.1%) and followed by right main bronchus (34.4%), left main bronchus (29.5%), left upper bronchus (16.4%), right middle bronchus (8.2%), right lower bronchus (6.6%) and left lower bronchus (3.3%). 5) Chronic granulomatous inflammation with or without caseation necrosis on microscopic examination was confirmed in 69.7%, bronchial washing AFB stain was positive in 34.1%, prebronchoscopic sputum AFB stain was positive in 88.1% and postbronchoscopic sputum AFB stain was positive in 30.1%.

• Journal of Nutrition and Health
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• 제30권2호
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• pp.155-169
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• 1997

This study investigated the effect of weight control by using the commercial appetite suppressant ((-)-hydroxycitric acid(HCA) formula) and nutrition education on 72 obese women over a period of 8 weeks. During the study it conducted nutritional education for women to control their weight, thus analyzed their changes in anthropometric variables. All obese women were randomized in a double-blind method to consume either HCA(HCA group : experimental group) or placebo(placebo group : control group). Two groups were also divided randomly into 2 groups combined with commercial formula diet in 1 meal a day(HD group and PD group : HCA + gormula diet and placebo + formula diet) or not(HO group and conducted with 4 groups(HD, HO, PD, and PO group). All subjects were assigned to consume 800-1500kcal/d balanced diet which is 500kcal less than their usual energy requirement. To evaluate the effect of the weight control program, weight, percent of body fat, waist and hip circumferences, and 5 skinfold thickness were measured up to 5 times in all obese women. The mean weight of the subjects at the onset of the study was 76.5$\pm$10.6kg. The mean body mass index(BMI) wa 30.1$\pm$3.8 and it was in the upper 5 percentile of mean BMI of Korean women. At the end of the program, mean weight loss was 3.5kg after 2 weeks(p<0.001), and 5.8kg after 4 weeks(p<0.001). The waist, hip ratio(WHR) and skinfold thickness measurements of biceps, triceps, subscapular, suprailiac and abdominum showed significant reduction over the entire study period(p<0.05). These outcome were evaluated by effect of nutritional education and counselling. The reduction of % of body fat was significantly different among the 4 groups. Women who administrated HCA demonstrated more change in weight, BMI than the placebo group. There was also significant reduction in body composition (% of body fat, WHR, and skinfold thickness) than the other groups. The HD group which was administrated HCA combined with formula diet was more decreased than other groups. It showed that this program using commercial HCA and formula diet induced not only a change in weight but also a change in body composition. The outcome of this study suggests that HCA has a more effctive change on weight control which is carried out with nutritional education and counselling.

• Journal of the Korean Wood Science and Technology
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• 제43권6호
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• pp.768-776
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• 2015

본 연구에서는 인도네시아 조림지에서 생장한 4수종의 효율적 활용방안을 마련하기 위해 콘칼로리미터법에 의해 연소특성을 조사하였다. 그 결과, 평균열방출량($HRR_{mean}$)은 비중에 비례하였으며, 총열방출량(THR) 및 연소시간(FT) 등열관련 계수도 같은 경향을 나타냈다. Albizia는 열방출 시간이 짧았고, Mindi는 4수종 중 점화시간(TTI)과 연소시간(FT)이 길어져 4수종 중 연소속도가 늦었고, 열방출 시간도 가장 길게 이어져 결국은 Mangium 수종과 비슷한 총열방출률을 나타내는 것을 확인할 수 있었다. Albizia는 공시수종 중 가장 높은 비소화면적 값을 나타내어 연기발생비율이 높았고, 반대로 Mindi는 가장 낮은 비소화면적 값을 나타내 연기발생비율이 낮았다. 초기 연기방출률은 Albizia가 높았으나 이후에는 Gmelina와 Mangium 의 연기방출률이 높아져 총연기발생량이 높게 나타났다. Gmelina는 불완전연소로 인해 연소기간 중 가장 많은 일산화탄소 연기를 생성하였고, $CO/CO_2$ 비율은 다른 수종에 비해 3배 이상 높았다.

• 한국언론정보학보
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• 제49권
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• pp.57-80
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• 2010

본 연구는 한반도 운하 건설에 대한 사회적 갈등문제에 대하여 국내 주요 언론들이 어떠한 시각에서 해석하고 평가함으로써 이슈에 대한 성격을 어떻게 규정하는지 살펴보았다. 이를 위하여 분석대상으로 국내 대표신문인 "조선일보", "한겨레신문", 그리고 "한국일보"를 통해 보도된 한반도 운하관련 뉴스 총 961건을 바탕으로 뉴스프레임 분석을 실시하였다. 분석결과, 정부주도 대형 국책공사의 성격상 스트레이트 뉴스 비율이 가장 높았다. 대운하관련 기사에 대한 프레임 분석결과, 정책집행, 경제적 결과 그리고 생태 환경프레임 비율이 상대적으로 높았다. 신문사별로 "조선일보"는 경제적 결과가, "한겨레신문"은 생태환경이, 그리고 "한국일보"는 정책집행 관련 프레임 비율이 높은 것으로 조사되었다. 주요 이익집단에 대한 분석을 살펴보면, 한반도 대운하 사업주체인 정부 여당 관련 보도빈도가 매우 많았다. "조선일보"는 경제 전문가 집단의 비율이 높은 것을 나타났고, "한겨레신문"은 생태 환경 관련 전문가 집단의 비율이 상대적으로 높았다. 이어서 주요행위자 프레임 분석으로는 정부의 권위적 정책집행과 경제적 결과 프레임에 대한 보도비율이 매우 높았다. 이는 대운하 건설 주체인 정부가 대국민을 상대로 운하건설에 대한 정당성과 필요성이 아닌 권위적이며 일방적으로 밀어 붙이고 있다는 뜻이기도 하다. 마지막으로 신문사별 틀 짓기 행위 프레임에 대한 특성을 살펴보면, "조선일보"는 정부의 열망과 성과 프레임의 비율이 높았으며, "한겨레신문"은 손익 프레임과 과정 프레임이 그리고 "한국일보"는 정부의 집행과정과 실체에 대한 갈등과 분쟁에 대한 보도비율이 높은 것으로 조사되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권4호
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• pp.588-596
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• 2020

Objective: The objective of this study was to investigate the effects of low doses of organic trace minerals (iron, copper, manganese, and zinc) on productive performance, egg quality, yolk and tissue mineral retention, and fecal mineral excretion of laying hens during the late laying period. Methods: A total of 405 healthy hens (HY-Line White, 50-week-old) were randomly divided into 3 treatments, with 9 replicates per treatment and 15 birds per replicate. The dietary treatments included feeding a basal diet + inorganic trace minerals at commercial levels (CON), a basal diet + inorganic trace minerals at 1/3 commercial levels (ITM), and a basal diet + proteinated trace minerals at 1/3 commercial levels (TRT). The trial lasted for 56 days. Results: Compared to CON, ITM decreased (p<0.05) egg production, daily egg mass, albumen height, eggshell strength, yolk Fe concentration, serum alkaline phosphatase activity and total protein, and increased (p<0.05) egg loss and feed to egg ratio. Whereas with productive performance, egg quality, yolk mineral retention, and serum indices there were no differences (p>0.05) between CON and TRT. The concentrations of Fe and Mn in the tissue and tibia were changed notably in ITM relative to CON and TRT. Both ITM and TRT reduced (p<0.05) fecal mineral excretion compared to CON. Conclusion: These results indicate that dietary supplementation of low-dose organic trace minerals reduced fecal mineral excretion without negatively impacting hen performance and egg quality.

• 한국도로학회논문집
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• 제7권3호
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• pp.31-42
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• 2005

본 연구는 도로용 포장재로서 포러스콘크리트의 실질적인 현장적용을 위한 자료제시와 성능향상 방안을 도출하기 위하여 실리카퓸과 강섬유 혼입률에 따른 포장용 포러스콘크리트의 물리 역학적 특성, 내구성 및 흡음특성을 평가하였다. 시험결과, 모든 시험조건에서 포장용 포러스콘크리트의 공극률과 투수계수는 국내외 기준치 및 제안값을 만족시키는 것으로 나타났고, 강도특성의 경우 압축강도는 대한주택공사 도로기준의 기준치를 모든 배합요인에서 만족시키는 것으로 나타났으나 휨강도의 경우에는 강섬유 혼입률 0.6vol% 이상에서 일본콘크리트공학협회 제안값을 만족시키는 것으로 나타났으며, 실리카퓸과 강섬유를 동시에 혼입한 경우가 우수한 강도특성을 나타냈다. 또한 내구성은 역학적 특성과 유사한 경향성을 나타내 실리카퓸과 강섬유를 동시에 사용한 경우가 가장 우수한 내구성능을 나타냈으며, 실리카퓸 10wt.%와 각섬유 0.6vol.%를 함께 사용한 경우 Plain의 경우에 비해 골재비산저항성은 27%정도, 동결응해저항성은 약 60%정도 개선되는 것으로 나타났다. 또한 포장용 포러스콘크리트의 흡음특성은 소음저감계수가 0.48로 나타나 50%에 가까운 흡음성능을 발휘하는 것을 확인할 수 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.68.1-68.1
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• 2012

The best part of graphene is - charge-carriers in it are mass less particles which move in near relativistic speeds. Comparing to other materials, electrons in graphene travel much faster - at speeds of $10^8cm/s$. A graphene sheet is pure enough to ensure that electrons can travel a fair distance before colliding. Electronic devices few nanometers long that would be able to transmit charge at breath taking speeds for a fraction of power compared to present day CMOS transistors. Many researches try to check a possibility to make it a perfect replacement for silicon based devices. Graphene has shown high potential to be used as interconnects in the field of high frequency electrical devices. With all those advantages of graphene, we demonstrate characteristics of electrical and optical properties of graphene such as the effect of graphene geometry on the microwave properties using the measurements of S-parameter in range of 500 MHz - 40 GHz at room temperature condition. We confirm that impedance and resistance decrease with increasing the number of graphene layer and w/L ratio. This result shows proper geometry of graphene to be used as high frequency interconnects. This study also presents the optical properties of graphene oxide (GO), which were deposited in different substrate, or influenced by oxygen plasma, were confirmed using different characterization techniques. 4-6 layers of the polycrystalline GO layers, which were confirmed by High resolution transmission electron microscopy (HRTEM) and electron diffraction analysis, were shown short range order of crystallization by the substrate as well as interlayer effect with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups on its layers. X-ray photoelectron Spectroscopy (XPS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation, and Fourier Transform Infrared spectroscopy (FTIR) and XPS analysis shows the changes in oxygen functional groups with nature of substrate. Moreover, the photoluminescent (PL) peak emission wavelength varies with substrate and the broad energy level distribution produces excitation dependent PL emission in a broad wavelength ranging from 400 to 650 nm. The structural and optical properties of oxygen plasma treated GO films for possible optoelectronic applications were also investigated using various characterization techniques. HRTEM and electron diffraction analysis confirmed that the oxygen plasma treatment results short range order crystallization in GO films with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups. In addition, Electron energy loss spectroscopy (EELS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation and XPS analysis shows that epoxy pairs convert to more stable C=O and O-C=O groups with oxygen plasma treatment. The broad energy level distribution resulting from the broad size distribution of the $sp^2$ clusters produces excitation dependent PL emission in a broad wavelength range from 400 to 650 nm. Our results suggest that substrate influenced, or oxygen treatment GO has higher potential for future optoelectronic devices by its various optical properties and visible PL emission.

• Journal of Astronomy and Space Sciences
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• 제29권2호
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• pp.151-161
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• 2012

An intensive analysis of 148 timings of V700 Cyg was performed, including our new timings and 59 timings calculated from the super wide angle search for planets (SWASP) observations, and the dynamical evidence of the W UMa W subtype binary was examined. It was found that the orbital period of the system has varied over approximately $66^y$ in two complicated cyclical components superposed on a weak upward parabolic path. The orbital period secularly increased at a rate of $+8.7({\pm}3.4){\times}10^{-9}$ day/year, which is one order of magnitude lower than those obtained by previous investigators. The small secular period increase is interpreted as a combination of both angular momentum loss (due to magnetic braking) and mass-transfer from the less massive component to the more massive component. One cyclical component had a $20.^y3$ period with an amplitude of $0.^d0037$, and the other had a $62.^y8$ period with an amplitude of $0.^d0258$. The components had an approximate 1:3 relation between their periods and a 1:7 ratio between their amplitudes. Two plausible mechanisms (i.e., the light-time effects [LTEs] caused by the presence of additional bodies and the Applegate model) were considered as possible explanations for the cyclical components. Based on the LTE interpretation, the minimum masses of 0.29 $M_{\odot}$ for the shorter period and 0.50 $M_{\odot}$ for the longer one were calculated. The total light contributions were within 5%, which was in agreement with the 3% third-light obtained from the light curve synthesis performed by Yang & Dai (2009). The Applegate model parameters show that the root mean square luminosity variations (relative to the luminosities of the eclipsing components) are 3 times smaller than the nominal value (${\Delta}L/L_{p,s}{\approx}0.1$), indicating that the variations are hardly detectable from the light curves. Presently, the LTE interpretation (due to the third and fourth stars) is preferred as the possible cause of the two cycling period changes. A possible evolutionary implication for the V700 Cyg system is discussed.

• 한국구조물진단유지관리공학회 논문집
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• 제19권4호
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• pp.92-100
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• 2015

본 연구는 폴리비닐 알코올 섬유 및 강섬유를 체적비율로 1.5% 혼입한 고인성 섬유보강 시멘트복합체에 대한 비상체의 고속충돌시험을 실시하고, 충돌조건에 따른 파괴특성을 실험적으로 검토하는 것을 목적으로 하였다. 비상체의 충돌에 의한 고인성 섬유보강 시멘트복합체의 파괴특성을 평가하기 위하여 화약압력식 충격시험장치를 활용하였으며, 충돌속도의 범위는 약 150~1,000m/s로 설정하였다. 파괴특성에 대한 평가결과, 고인성 섬유보강 시멘트복합체는 섬유를 혼입하지 않은 Plain시험체의 약 3배 이상의 비상체 운동에너지가 작용하는 범위에서도 표면관입의 파괴등급으로 평가되었으며, 시험체가 파단되지 않는 내충격성능이 확인 되었다. 또한, 충돌시험 전후에 대한 시험체의 질량감소율의 경우, Plain시험체는 비상체의 운동에너지의 증가율과 비례적인 관계를 보였지만, 고인성 섬유보강 시멘트복합체는 비상체의 운동에너지의 영향을 크게 받지 않는 것으로 나타났다. 특히, 이와 같은 경향은 시험체 배면의 파괴특성과 밀접한 관계를 가지며, S시험체에 비해 PVA시험체의 배면박리 억제효율이 큰 것으로 평가되었다. 한편, 국부손상에 대한 표면관입깊이 및 배면박리깊이의 관계를 검토한 결과, 고인성 섬유보강 시멘트복합체는 Plain과 달리 시험체 단면의 중앙선을 기준으로 배면에 가까운 영역에서 배면박리가 발생하는 것을 알 수 있었다. 본 연구를 통해 비상체의 충돌에 대한 고인성 섬유보강 시멘트복합체의 주요 파괴거동이 검토되었으며, Plain과 비교하여 내충격성능의 향상을 명확히 확인하였다.