• Agricultural and Biosystems Engineering
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• 제1권1호
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• pp.30-37
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• 2000

Wet porous media representing agronomic soil that contains variable water content with variable electrolyte concentration was measured to study the shape of the curves of the electric double layer capacitance versus frequency (from 10 KHz to 10 MHz. This was done in an attempt to find the lowest practical operating frequency for developing low cost dielectric constant soil moisture probes. Cellulose sponge was used as the porous media. A high frequency electronic bridge circuit was developed for measuring the equivalent network parallel resistance and capacitance of porous media. It appears that the effects of the electric double layer component of the total parallel network capacitance essentially disappear at operating frequencies greater than approximately 25 MHz at low electrolyte concentrations but are still important at 50 MHz at higher concentrations. At these frequencies, the double layer capacitance masks the diffusion region capacitance where true water content capacitance values reside. The general shape of the curve of volumetric water content versus porous media dielectric constant is presented, with an empirical equation representing data for this type of curve. It was concluded that the lowest frequency where dielectric constant values which represent true water content information will most likely be found is between 30 and 50 MHz at low electrolyte concentrations but may be above 50 MHz when the total electrolyte concentration is near the upper level required for most mesophyte plant nutrition.

• 한국안전학회지
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• 제17권4호
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• pp.52-60
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• 2002

Failure criterion is a parameter to represent the resistance to failure of locally wall thinned pipe, and it depends on material characteristics, defect geometry, applied loading type, and failure mode. Therefore, accurate prediction of integrity of wall thinned pipe requires a failure criterion adequately reflected the characteristics of defect shape and loading in the piping system. In the present study, the finite element analysis was performed and the results were compared with those of pipe experiment to develop a sound criterion for failure of internally wall thinned pipe subjected to combined pressure and bending loads. By comparing the predictions of failure to actual failure load and displacement, an appropriate criterion was investigated. From this investigation, it is concluded that true ultimate stress criterion is the most accurate to predict failure of wall thinned pipe under combined loads, but it is not conservative under some conditions. Engineering ultimate stress estimates the failure load and displacement reasonably for al conditions, although the predictions are less accurate compared with the results predicted by true ultimate stress criterion.

• 한국산학기술학회논문지
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• 제19권5호
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• pp.263-274
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• 2018

본 연구에서는 순수형 보강토교대의 상부구조로 적용되는 슬래브교에 대한 적용성을 검토하고 보강토 교대의 외적/내적 안정성에 대해 검토하였다. 상부구조인 슬래브교의 연장은 10.0 m ~ 20.0 m, 두께는 0.7 m ~ 0.9 m를 대상으로 하여 구조해석을 수행하여 보강토교대의 교량받침에 작용되는 사하중과 활하중에 의한 반력을 산정하였다. 슬래브교는 연장 20.0m까지 순수형 보강토교대의 허용 접지압 200 kPa을 만족하였다. 순수형 보강토교대의 외적 안정성은 보강토체의 기하형상에 지배되기 때문에 상부구조의 하중에 의한 안전율 변화는 작은 것으로 나타났다. 지지력에 대한 안전율은 기초지반의 강성은 상수이지만 활동력인 상부구조의 하중은 증가되므로 감소되었다. 그리고 상부구조로 인해 보강토옹벽 상단에 작용하는 접지압이 200 kPa을 초과할 경우, 순수형 보강토교대에서는 전면벽체에 작용하는 수평토압이 과도하게 증가되어, 최상단 보강재에서 내적안정성인 인발과 파단에서 허용안전율을 만족하지 못하였다. 순수형 보강토교대의 효율적 설계 및 성능 확보를 위해서는 보강토체 상단에 배치된 보강재의 인발저항력과 장기허용인장력을 증가시키는 것이 필요한 것으로 분석된다.

• 원예과학기술지
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• 제32권5호
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• pp.673-683
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• 2014

2010년 대전에서 채집한 흰가루병이 발생한 오이 잎의 단일 병반에서 흰가루병균을 분리하였고, 이 흰가루병균은 광학현미경 하에서의 형태학적 특성과 멜론 판별품종에서의 저항성 반응에 따라 Podosphaera xanthii race 1으로 동정되었다. 박과 작물 흰가루병에 대한 저항성 검정에 효율적인 생육시기를 결정하기 위하여, P. xanthii race 1에 대한 오이품종들의 생육시기에 따른 저항성 차이를 조사하였다. 시판중인 오이 34개 품종의 이 흰가루병균에 대한 저항성을 온실에서 3종류의 생육시기에서 실험한 결과, 떡잎에서의 저항성 반응은 본엽에서와 일치하지 않았으며, 본엽 1엽에서의 흰가루병 발생 정도는 식물 전체의 흰가루병 발생량과 높은 상관관계를 보였다. 따라서 본엽 1엽에 흰가루병이 충분히 발생하는 시기에 1엽만을 대상으로 저항성을 검정하는 것이 효율적이라 생각되었다. 또한, 박과 작물의 재배 시기에 따른 저항성 차이를 조사하기 위하여 오이 12개 품종을 4개의 재배 시기에 그리고 멜론 26개 품종을 3개의 재배시기에 흰가루병 발생을 조사하였다. 오이 품종들 중 6개 품종은 재배 시기에 따라 흰가루병 저항성에 차이를 보였으며, 온도가 올라가면 저항성이 증가함을 알 수 있었다. 이와 달리 멜론 품종들은 실험한 품종 중 5개가 고도의 저항성을 보였으며, 이들의 흰가루병 저항성은 재배 시기에 따라 거의 차이를 나타내지 않았다. 한편, 대전에서 분리한 P. xanthii race 1 균주는 수박 7개 품종에 대하여 병원성을 나타내지 않았다. 하지만 모든 P. xanthii race 1 균주가 수박에 비병원성인지는 race 1 균주를 더 많이 확보하여 확인하는 것이 필요하다.

• 대한기계학회논문집A
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• 제26권6호
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• pp.1120-1126
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• 2002

Machining characteristics of tool steels manufactured by electro slag casting process has been investigated in this study. For the estimation of machinability, turning and drilling tests are carried out. The chip shapes at various velocities are investigated for the comparison of turning workabilities of tool steels because the chip shapes reflect characteristics of cutting resistance. In case of drilling test, feed motor currents measured by a hall sensor are used as a measure for the drilling resistance. The machining characteristics of the tool steels are strongly correlated with tensile properties, such as tensile strength, hardness, and ductility. In case of turning workability, it was found to be favoured by the higher tensile strength, while the opposite is true far the drilling workability. The electro-slag casted materials show better turning workability in the viewpoint of chip shapes and, the quenching-tempered electro-slag casted material has relatively better drilling machinability than that of the annealed one.

• Journal of Chest Surgery
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• 제17권3호
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• pp.339-345
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• 1984

Thirty four patients with a ventricular septal defect, aged 2 months to 24 years [median 2.33 years], had lung biopsies during open heart procedures to assess the degree of pulmonary vascular disease. The patients were divided into two groups according to their age; group 1 - under 2 years of age [15 patients], and group 2- over 2 years of age [19 patients]. The, pathologic change of the pulmonary arterioles was correlated with pre-operative hemodynamic data in 34 patients. There was no significant correlation between the severity of pulmonary vascular disease according to Heath-Edwards classification and the patients age [X2=1.8381, P=0.1751 ]. There was a significant correlation between degree of medial wall thickness and arteriolar diameter and the level of preoperative peak pulmonary artery pressure and peak systemic artery pressure [Pp/Ps]. Also, there was a good correlation between the preoperative pulmonary vascular resistance and systemic vascular resistance [Rp/Rs]. There was no significant correlation between wall thickness and Pp/Ps, and Rp/Rs below the age of 2 years. We conclude that, in patients over 2 years of age, there was a significant correlation between the medial wall thickness of the pulmonary arteriole and elevation of Pp/Ps and Rp/Rs. This is not true in patients under 2 years of age.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.489-492
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• 1997

The general pattern of adaptation in the appendicular skeleton with aging is that the subperiosteal apposition of bone occur along with endosteal absorption. This remodeling of diaphysis to a cylinder of larger diameter is hypothesized to serve a mechanical compensatory unction by increasing the moment of inertia as the cortex thins with aging. These findings is only true of the diaphysis of long bone. Measuring the area and inertia at each section of femur, the age-related change of proximal emur and diaphysis is observed. After screening by physical and radiological examination, 200 normal Korean adults divided 5 groups in both male and female based on age. Twenty persons were in each group. One femur in each person was analyzed using CT images. femur scanned with 60 to 80 slices and this images were digitized. Then 2-D images were reconstructed into 3-D images. Using the nonlinear method, normalization and interpolation technique, 7 locations of interest (trochanteric area: 1, 2 subtrochanteric area: 3, 4, isthmic area: 5, 6, 7) were determined. On the each cross section at each location, the area (total, cortical and medullary) and 5 inertia of moment were measured. The results were analyzed statistically. With aging, significant area change occurred mainly in diaphysis and female. In trochanteric area, no significant change was noted. With aging, total and medullary area were increased, but cortical area was not changed. In diaphysis, lateral bendingresistanceincreasedsignificantly. No inertia change was noted in trochanteric area. Anteroposterior bending resistance was constant with aging. In more than age 60, total area and medullary area were larger than that of others. Lateral bending resistance was higher especially in diaphysis. In diaphysis, with aging, the decreased properties is compensated with the increased lateral bending resistance by geometric remodeling. In trochanteric area, no compensation occur. With aging, especially in more than age 60, the higher rate of trochanteric fracture is expected.

• 영어영문학
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• 제55권4호
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• pp.517-538
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• 2009

This study explores the possibility of finding intersections of commonness and differences between Mahasweta Devi's short stories, "The Hunt" and "Douloti the Bountiful" and Angela Carter's "Flesh and the Mirror" and "Master" in Fireworks. At appearance, Carter as a writer of Great Britains and Devi as a writer of India in postcolonial period do not seem to share any commonness. This study, however, tried to find "common differences," to quote Chandra Mohanty's terminology, as a basis of solidarity possible between these two different feminist writers. Another concept appropriated in this process of comparing Carter and Devi is Gayatri Spivak's 'planetary comparative literature,' which contends the necessity of critical regional studies and the study of Asian Literature in the study of English literature. Devi and Carter, despite their historical, geopolitical and racial differences, share commonness in depicting Asian or colonized women not only as the oppressed others but also as the subjects who show potential for resistance and independence. Carter portrays Japanese women as the colonized and oppressed others of Japanese society, even though Japan did not have any colonial history. Devi finds in the postcolonial Indian women both the oppressed in the interstice of colonial/postcolonial/patriarchal Indian history and the potential for resistance. Despite some limitation in her understanding of Asia, Carter shows her insight to accept Asia as a true origin of her self-knowledge and performativity of her woman's role. Despite their differences, these two writers use Freud's 'unheimlich' from the feminist point of view, in general. Devi's depiction of the heroine's dead body at the end of the story implicates the possibility of resistance through women's 'uncanny' bodies. Carter converts Freudian and negative connotation of woman's body into positive and comfortable 'home' as a starting point of her self knowledge.

• 대한한의학회지
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• 제38권4호
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• pp.104-109
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• 2017

Objectives: Epicardial fat is true visceral fat that is known to be associated with metabolic syndrome, high abdominal fat, insulin resistance, coronary artery diseases, low coronary flow reserve and subclinical atherosclerosis. Dampness-Phlegm pattern is one of the pattern diagnosis of traditional Korean medicine. Previous studies showed that Dampness-Phlegm pattern is associated with hypertension, dyslipidemia, metabolic syndrome. This study is intended to find association between Dampness-Phlegm pattern and epicardial fat thickness. Methods: This study was a community-based single center trial. Ischemic stroke patients within 30 days after their ictus were enrolled. Epicardial fat thickness was measured using transthoracic echocardiography. Other measured and obtained variables are medical history, weight, height, body mass index, fasting blood glucose, cholesterol, triglycerol, high density lipoprotein, lipid and low density lipoprotein. Results: Three hundred sixty six were enlisted, and one hundred forty were diagnosed with the Dampness-Phlegm pattern. Dampness-Phlegm pattern group had significantly thicker epicardial fat. Binary logistic regression also showed statistically significant result. Conclusions: This study showed close association between epicardial fat and Dampness-Phlegm pattern. This result suggests a clue to standardization of pattern identification.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.571-574
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• 2009

Metal oxide/metal bilayer structures are explored as contacts with a low injection barrier in organic thin-film transistors (OTFTs) in an effort to realize their true potential for low-cost electronics. OTFTs with a bilayer electrode of $WO_3$ (10nm) and Al shows a saturation mobility as large as 0.97 $cm^2$/Vsec which are comparable to those of Au-based control samples (~0.90 $cm^2$/Vsec). Scaling of contact resistance with respect to the thickness of $WO_3$ layer is also discussed.