• Wind and Structures
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• 제20권5호
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• pp.623-642
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• 2015

Several international codes have been developed for evaluating wind loads on structures; however, the wind structure interaction could not be accurately captured by these codes due to the gusty nature of wind and the dynamic behavior of structures. Therefore, the alternative wind tunnel testing was introduced. In this study, an introduction to the available approaches for wind load calculations for tall buildings was presented. Then, a comparative study between different codes: the Egyptian code, ECP 201-08, ASCE 7-05, BS 6399-2, and wind tunnel test results was conducted. An investigation has been carried out on two case studies tall buildings located within the Arabian Gulf region. Numerical models using (ETABS) software were produced to obtain the relation between codes analytical values and wind tunnel experimental test results for wind loads in the along and across wind directions. Results for the main structural responses including stories forces, shears, overturning moments, lateral displacements, and drifts were presented graphically in order to give clear comparison between the studied methods. The conclusions and recommendations for future works obtained from this research are finally presented to help improving Egyptian code provisions and show limitations for different cases.

• 한국물환경학회지
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• 제27권1호
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• pp.44-53
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• 2011

Membrane bio-reactor (MBR) has several advantages over the conventional activated sludge process, including a high biomass, low sludge production, and better permeate quality. Therefore, the MBR have gained popularity for municipal and industrial wastewater treatment. However the MBR usually were used for sewage and low streng th wastewater treatment because of membrane fouling problem and limitation of oxygen transfer into biomass. In this study, the hybrid process combining MBR and pure oxygen was tested for high strength organic wastewater treatment in the COD loading range from 2 to $10kgCOD/m^3{\cdot}day$. The hybrid process, membrane coupled pure oxygen high compact reactor (MPHCR), had been operated for one year and operation parameters, the effect of COD loading, MLSS concentration and the location of membrane module were studied for membrane fouling characteristic. Also membrane resistance test and the component of foulant was analyzed to investigate what is specific foulant in the MBR.

• 음성과학
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• 제9권3호
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• pp.185-200
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• 2002

The current study confirmed the existence of an ip prosodic level in French intonation structure, as previously proposed by Sun-Ah Jun & $C\acute{e}cile$cile Fougeron (2000). However, in contrast to the previous suggestion of the plateau realized in an ip in several syntactic structures, the current study supposed that the plateau doesn't come from the different type of syntactic structures but arise from the unspecified syllables without any PA in an ip. Because if we limited ip phrasal tone to the syntactic structure, it would be difficult to find the more general reasons of ip level. Besides /Hi/ and /$H^*$/ we also used /$Hi^*$/ for the focused syllable in the current study. In emphasized sentences, in general, /$Hi^*$/ appeared in the first or second syllable of a leftward AP in an ip and /$H^*$/ in the final syllable of a rightmost AP of an ip, In contrast to these PAs, /$Hi^*$/ might appear in any syllable in an ip, but not to far from /$H^*$/ because the duration time and length t of plateau realized between /$Hi^*$/ and /$H^*$/ or /Hi/ and /$H^*$/ would make an essential harmonious rhythmic unit, Therefore, the current study determined the duration time and the number of syllables realized in each plateau in an ip level composed of more than one AP. As a phrase constituent structure, there is a practical need for intermediate prosodic units to allow for generalization over the many possible combinations of prosodic patterns that can occur. Further evidence is still needed to analyze and relate the different pitch ranges of the plateau of an ip according to the syntactic structure, to identify the considerable character in the French prosodic hierarchy.

• 대한기계학회논문집 C: 기술과 교육
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• 제1권1호
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• pp.129-138
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• 2013

화력발전소의 보일러를 일정한 화력으로 가동하기 위해서는 일정한 통풍량을 유지시켜야 한다. Main Bearing Assembly Unit 일정한 통풍량을 유지시키기 위하여 Fan을 회전시킨다. 그러나 점차 발전량이 많아지는 반면에 발전을 위하여 투입되는 석탄의 질은 초기의 보일러 설계 기준보다 나빠지고 있다. 특히 원가절감의 일환으로 또는 자원의 고갈로 인한 고급품질의 석탄 확보가 어려움으로 인하여 점차 낮은 질의 석탄이 투입되고 있다. 이로 인하여 초기 설계시의 Main Bearing Assembly의 수명보다 약 절반의 수명인 2~3년의 주기로 Main Bearing Assembly의 정비교체가 요구되고 있다. 본 연구에서는 Main Bearing Assembly Unit의 역설계 해석을 통해서 수명단축의 원인을 분석하고 초기 목표 수명을 가질 수 있도록 새로운 시스템으로 개선하여 개발하고자 한다.

• Journal of Preventive Medicine and Public Health
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• 제33권1호
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• pp.36-44
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• 2000

Objective : The heart diseases are known as a major cause of sudden death, as well as a cause of poor life-quality of school-age children. But there have been few mass screening of heart diseases in these children in Korea. This study was done to estimate the prevalence of heart diseases of these population. Methods : We screened all elementary students(grade 1) in 12 cities and 16 counties(Gun) in Kyonggi province from 1992 to 1955. The first screening was done by auscultation of doctors and simultaneously by checking using 'auto-interpreter of EKG-cardiac sound' (Fukuda Densi ECP 50A). We conducted luther examinations to whom classified as being abnormal condition in first screening, by using EKG, chest x-ray, doppler echocardiograpy(if needed). Results : The total number of examined students was 161,308(92% of the population), the male were 83,238 and female were 78,070. The congenital heart diseases(CHD) patients were 290(18 per 10,000) - male 155(18.6 per 10,000) and female 135(17.3 per 10,000). The most frequent disease was ventricula septal defect(VSD, 45.5%), Atrial septal defect(ASD, 14.8%), Tetralogy of Follot(TOF, 11.7%), and Patent Dutus Arteriosis(PDA, 7.6%) in order. In female, the order was VSD(48.1%), ASD(13.3%), TOF(11.1%), and PDA(10.4%). The total number of EKG abnormality were 433(62.7 per 10,000) among 69,056 screened children in 1995. The complete right bundle branch block(CRBBB) and paroxymal ventricular contraction(PVC) were frequent(26.6%, 26.3% in each), and incomplete right bunddle branch block(IRBBB, 14.6%), paroxymal atrial contraction(PAC, 6.7%), abnormal Q(5.8%), Wolf-Pakinson-White syndrom (5.5%) in order. In female, the most frequent abnormality was PVC(29.8%), and CRBBB(19.9%) in order. Conclusion : We could present the stable prevalence of the rare heart disease. The prevalence of congenital heart diseases was 18.0 per 10,000 and of EKG abnormality was 62.7 per 10,000 among school children.

• 대한한방소아과학회지
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• 제13권1호
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• pp.191-204
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• 1999

Background: Nasal polyps are benign mass of nasal mucose, chronic sinusitis are swelling of nasal mucose, so nasal polyps and chronic sinusitis take a place at the same time. Nasal polyps are located lateral wall of nose, middle meatus, between middle nasal concha and inferior nasal concha. Objective: To demonstrate the effect of herbal medicine therapy in the chronic sinusitis and nasal polyps before and after treatment using computed tomography (CT). To compared before and after treatment of otitis media using earscope. Materials and methods: Five patients (4 mail and 1 femail) treated in our hospital between August 1998 and July 1999 were studied. Ages ranged from 9 to 23 years (mean age:13 years). All patients had a underlying family history, and past history(allergy or sinusitis of parents or brothers). Illness period was from 1 to 36 months (mean period:10.5 month). To ascertain the efficacy of treatment, CT were checked out. In the CT, three images were obtained 2cm interval on the coronal and axial plan. We classified treatment period into the type of allergic disease. Gamihyunggyeyungyo-tang was administered mainly. Gamigwaghyangjeungki-san, Gamizwakwi-eum and Gamihyangso-san were administered for through oral route additional symptoms. Results: Treatment period was from 126 to 157 days (mean period:140.7 days). To 3 patients with chronic sinusitis and nasal polyp, treatment period was 140.7 days, to 2 patients with otitis media and chronic sinusitis and nasal polyp, treatment period was 141.5 days. So they had no significance. Not nasal polyp from middle meatus, but also polypoid mucosal change of maxillary sinus is polyps Conclusion: We know that herbal medicine therapy is the effective treatment of pediatric chronic sinusitis and otitis media using earscope and CT. Herbal medicine therapy was effective in increasing immunity, inhibiting allergic reaction and inflammation of respiratory system. we practice ECP(eosinophil cataionic protein) and MAST examination, objectify herbal medicine therapy.

• 한국결정성장학회지
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• 제7권1호
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• pp.70-75
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• 1997

Electron beam 증착법을 보완하여 GaAs(100)기판위에 cubic(zinc blende) CdSe 에피충을 성장시켜 그의 특성을 조사하였다 .. CdSe 에피충의 격자 상수는 6.077 A였으며, 배향 성은 ECP 패번에 의하여 확인되고 결정성은 DCXR curve로 관찰하였다. 상온에서 측정된 H Hall data로는 에피충의 운반자 농도와 이통도는 각각 1018cm-3, 102cm2N' see 정도임을 알았 고 30 K에서 측정한 PC spectra peak는 cubic CdSe의 free exciton에 기인된 것으로 1.746 e eV에서 예리하게 나타냐고 있음을 보여주고 있다.

• 한국표면공학회지
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• 제56권6호
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• pp.401-411
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• 2023

This study investigates the synthesis, characterization, and application of zinc oxide (ZnO) nanoparticles for corrosion resistance and stress corrosion cracking (SCC) mitigation in high-temperature and high-pressure environments. The ZnO nanoparticles are synthesized using plasma discharge in water, resulting in rod-shaped particles with a hexagonal crystal structure. The ZnO nanoparticles are applied to Alloy 600 tubes in simulated nuclear power plant atmospheres to evaluate their effectiveness. X-ray diffraction and X-ray photoelectron spectroscopy analysis reveals the formation of thermodynamically stable ZnCr₂O₄and ZnFe₂O₄ spinel phases with a depth of approximately 35 nm on the surface after 240 hours of treatment. Stress corrosion cracking (SCC) mitigation experiments reveal that ZnO treatment enhances thermal and mechanical stability. The ZnO-treated specimens exhibit increased maximum temperature tolerance up to 310 ℃ and higher-pressure resistance up to 60 bar compared to non-treated ZnO samples. Measurements of crack length indicate reduced crack propagation in ZnO-treated specimens. The formation of thermodynamically stable Zn spinel structures on the surface of Alloy 600 and the subsequent improvements in surface properties contribute to the enhanced durability and performance of the material in challenging high-temperature and high-pressure environments. These findings have significant implications for the development of corrosion-resistant materials and the mitigation of stress corrosion cracking in various industries.

• Clinical and Experimental Pediatrics
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• 제46권5호
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• pp.495-499
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• 2003

목 적 : 천식 환아에서 호산구 활성도를 반영하는 ECP 혹은 EPX치는 대부분 상승되어 있으므로 이들 지표들은 천식의 질병활성도와 관련되어 있어 치료 효과의 추적 및 판정에 도움을 줄 수 있다. 요중 EPX는 모든 연령의 환아에서 비침습적으로 손쉽게 얻을 수 있는 장점이 있다. 본 연구에서는 호산구 활성 지표로서 요중 EPX의 유용성을 살피고자 메타콜린 기도 유발 시험을 시행하여 천식의 병력 기간, 기관지 과민 반응과의 관계를 살펴 천식의 정도 판정 및 관리에 활용하고자 하였다. 방 법 : 경증 또는 중등증 천식 환아 중 증상이 조절되고 있는 8세에서부터 19세까지의 25명을 대상으로 메타콜린 기도 유발 시험을 시행하고 소변을 채취하여 요중 EPX를 측정하였다. 결 과 : 요중 EPX치는 초기 기도 반응(0-3시간)에서 유발 시험 전의 기저치보다 유의하게 증가하였다. 대부분 환아에서 요중 EPX는 후기 기도 반응(4-7시간)시 약간의 증가를 보이고 이후에는 기저치로 감소하는 양상이었다. 요중 EPX는 PC20 농도가 낮을수록, 천식의 병력이 오래될수록 증가하는 경향을 보였다. 결 론 : 요중 EPX 측정은 비침습적이고 손쉬운 방법으로 기도 염증 반응 및 과반응을 평가하고 나아가 천식 관리에 유용하게 사용할 수 있을 것이다.

• 유기물자원화
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• 제14권3호
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• pp.126-137
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• 2006

고농도 암모니아성 질소를 함유한 프로피온산의 처리시 유기물과 입상슬러지의 거동을 평가하기 위하여 12개월간 상향류 혐기성 슬러지 블랭킷 (UASB) 반응조를 운전하였다. UASB 반응조의 경우 암모니아성 질소 농도 6000mg-N/L까지는 80%의 COD 제거가 가능하였다. 암모니아성 질소 농도를 고농도로 유지하는 경우 유출수의 프로피온산의 농도는 증가하였으나 초산 농도는 상대적으로 매우 낮게 유지되었다. 암모니아성 질소 농도 8000mg-N/L에서는 낮은 메탄 발생량에도 불구하고 유출수의 휘발성 현탁 고형물 농도가 증가하였으며, 이는 입상슬러지의 체외고분자 물질의 감소에 기인하는 것으로 판단된다. 개미산, 초산 및 프로피온산을 기질로 이용한 비메탄 활성도는 암모니아성 질소 농도 증가에 따라 감소하는 경향을 보였다. 일반화된 비선형 모델을 이용하여 산정한 동력학적 상수값은 개미산, 초산 및 프로피온산을 기질로 사용한 경우 각각 3.279, 0.999 및 0.609로 나타났다. 비메탄 활성도에 50% 저해를 미치는 암모니아성 질소 농도는 개미산, 초산 및 프로피온산을 기질로 이용한 경우 각각 2666, 4778 및 5572mg-N/L로 나타나 수소 이용 메탄균의 저해가 가장 큰 것으로 나타났다. 입상슬러지는 대나무 모양(bamboo-shape form)의 methanothrix 형태의 미생물이 주종을 이루고 있으며, hydrogen-producing acetogens와 hydrogen-consuming methanogens이 존재하는 것으로 나타났다.