• 대한기계학회논문집A
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• 제35권2호
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• pp.213-221
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• 2011

알루미늄 재질의 도시철도차량 차체의 경량화를 위해 이중 판재구조로 이루어진 철도차량용 알루미늄 압출재의 최적설계를 수행하였다. 위상최적설계 기법을 이용하여 알루미늄 차체에서 가장 큰 중량을 차지하는 하부 프레임 베이스 플레이트의 경량화된 위상을 도출하였고, 이를 기반으로 압출재 부재별 치수 최적화를 수행하였다. 하부 프레임 다음으로 큰 중량을 차지하는 측면 프레임 압출재에 대해서는 치수 최적화를 통하여 경량설계를 수행하였다. 최적설계안과 현재 설계의 최대발생응력과 최대 변형량을 비교하여 최적설계결과의 타당성을 검증하였다. 이 과정을 통하여 언더프레임과 사이드프레임의 중량을 현재보다 평균 12% 줄일 수 있었고, 차체 전체로는 8.5%의 경량화 효과를 얻었다.

• Archives of Reconstructive Microsurgery
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• 제14권2호
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• pp.152-156
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• 2005

Purpose: We reconstructed the thumb with groin flap combined with secondary heterodigital neurovascular island flap and report our 6 cases. Materials and Methods: Between March 2003 and August 2004, 6 degloving thumbs or amputation of thumbs were reconstructed with groin flap combined with secondary heterodigital neurovascular island flap. There ware 4 men and 2 women, and mean age was 42.2 years. The following parameters were evaluated. Results: Recipient thumb was no limitation of apposition. but flexion contracture of interphalangeal joint was about 10 degree in two cases. Average grip power were 80% and average pinch power were 70% that of the normal thumb. The two point discrimination was average 10.5 mm and double sensibility in 2 cases. 2 patients have cold intolerance. Neuroma formation was not made. Cosmetic results as judged by patients were that 4 cases are good and 2 cases are fair. Conclusion: If massive skin defect after degloving thumb or amputation of thumb are present, we consider the numerous methods for reconstruction of thumb. This surgical procedure is good methods because of it's pliability, sensation, satisfactory functional results but major disadvantage are the staged operation and cosmetic effect of the absence of thumb nail.

• 한국산학기술학회논문지
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• 제13권8호
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• pp.3307-3314
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• 2012

농어촌 주택 표준모델에 대한 연간 건물에너지요구량을 DesignBuilder를 사용하여 계산하였다. 실내설정온도, 외벽의 열관류율, 창호타입, 환기량을 변화시키며 건물의 설계/운영 변수들이 에너지요구량에 미치는 영향을 분석하였다. 건물의 크기와 상관없이 난방에너지요구량이 냉방에너지요구량보다 더 큰 것으로 나타났다. 단열재 두께를 증가시켜 외벽의 열관류율을 감소시키면 단열효과의 증가로 난방에너지요구량은 감소하지만 냉방에너지요구량이 증가한다. 하지만 외벽의 열관류율 조절을 통한 난방에너지요구량의 절감에는 한계가 있으므로 외부에 직접 노출된 외벽의 면적을 최소화하는 것이 더 효과적인 것으로 판단된다. 계산에 사용된 4가지 창호 중 일반 이중창호가 난방에너지요구량 측면에서 가장 유리한 것으로 나타났다. 침기량은 일정하게 유지하고 단위시간당 환기량을 증가시킨 경우 냉방에너지요구량은 큰 변화가 없었으나 난방에너지요구량이 증가하였다. 실내의 공기질이 만족되는 범위 내에서 환기량을 최소화하는 것이 연간 건물에너지요구량을 줄이는데 유리한 것으로 판단된다.

• 한국식품영양과학회지
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• 제24권1호
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• pp.1-9
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• 1995

1, 25(OH)2-23ene-D3 is a novel vitamine D3 analog which has a double bond between C-23 and C-24. We describe the effects of this analog on cell differentiation and cell proliferation in vitro using the human histiocytic lymphoma cell line U937, and on calcium metabolism in rats in vivo. In the present investigation 1, 25(OH)2-23ene-D3 was compared to the natural metabolite of vitamin D3, 1$\alpha$, 25-dihydroxycholecalciferol[1, 25(OH)2-23ene-D3 was more potent than 1, 25(OH)2-23ene-D3 for inhibition of proliferation and induction of differentiation of U937 cells. Especially, its effect on induction of differentiation, as measured by superoxide production and nonspecific esterase(NSE) activity, was about 20-fold more potent that 1, 25(OH)2-23ene-D3. This analog morphologically and functionally differentiated U937 cells to monocyte-macrophage phenotype showing a decrease of N/C ratio in Giemsa staining and the increase of adherence ability to surface. Intraperitoneal administration of 1, 25(OH)2-23ene-D3 to rats showed that the compound had at least 50 times less activity than 1, 25(OH)2-23ene-D3 in causing hypercalcemia and hypercalciuria. The strong direct effects of 1, 25(OH)2-23ene-D3 on cell proliferation and cell differentiation, coupled with its decreased activity of calcium metabolism make this compound an interesting candidate for clinical studies including patients with leukemia, as well as several skin disorders, such as psoriasis.

• Steel and Composite Structures
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• 제30권5호
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• pp.405-416
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• 2019

Profiled composite slab has been widely used in civil engineering due to its structural merits. The extension of this concept to the bearing wall forms the profiled composite wall, which consists of two external profiled steel plates and infill concrete. This paper investigates the structural behavior of this type of wall under axial compression. A series of compression tests on profiled composite walls consisting of varied types of profiled steel plate and edge confinement have been carried out. The test results are evaluated in terms of failure modes, load-axial displacement curves, strength index, ductility ratio, and load-strain response. It is found that the type of profiled steel plate has influence on the axial capacity and strength index, while edge confinement affects the failure mode and ductility. The test data are compared with the predictions by modern codes such as AISC 360, BS EN 1994-1-1, and CECS 159. It shows that BS EN 1994-1-1 and CECS 159 significantly overestimate the actual compressive capacity of profiled composite walls, while AISC 360 offers reasonable predictions. A method is then proposed, which takes into account the local buckling of profiled steel plates and the reduction in the concrete resistance due to profiling. The predictions show good correlation with the test results.

• 한국산업융합학회 논문집
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• 제21권6호
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• pp.337-344
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• 2018

Food irradiation is important not only in ensuring safety but also improving antioxidant activity of peaches. Our objective was to establish the best irradiation treatment for peaches by calculating dose distribution using Monte Carlo simulation. 3-D geometry and component densities of peaches, extracted from CT scan, were entered into MCNP to obtain simulated dose distribution. Radiation energies for electron beam were 1.35 MeV (low energy) and 10 MeV (high energy). Co (1.25 MeV) and the Husman irradiator, containing three sealed Cs source rods in an annular array, were used for gamma irradiation. At 1.35 MeV electron beam simulation, electrons penetrated well beyond the peach skin, enough for surface treatment for microorganisms and allergens. At 10 MeV electron beam simulation, for top-beam only treatment, doses at the core were the highest and for double beam treatment, the electron energy was absorbed by the entire sample. At Co source, the radiation doses were presented on the whole area. At Cs source, the dose uniformity ratios were 2.78 for one source and 1.48 for three ones at 120 degrees interval. Proper control of irradiation treatment is critical to establish confidence in the irradiation process.

• 대한정형외과학회지
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• 제56권2호
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• pp.168-172
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• 2021

후천성 수지 섬유각화종(acquired digital fibrokeratoma)은 비교적 드문 피부 양성 종양으로 손가락과 발가락 말단부에 주로 발생한다. 일반적으로 성인에서 단독으로 발생하는 과각화성의 돔 형태(dome-shaped) 종괴로 관찰되며 때로는 잔류 과다지(rudimentary supernumerary digit) 양상이거나 손톱(accessory nail)이 여러 개인 양상, 혹은 사마귀와 같은 보다 일반적인 상태로 오진되는 경우가 있다. 발생기전은 아직 확실하지 않으나 물리적인 외상이 가장 흔한 원인으로 알려져 있다. 저자들은 36세 남자 환자에서 좌측 제2수지의 외상 후 발생한 잔류 과다지 형태의 후천성 수지 섬유각화종을 진단하고 절제 생검술을 시행한 후 조직학적 검사를 통해 확진한 1예를 문헌 고찰과 함께 보고하고자 한다.

• Steel and Composite Structures
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• 제51권6호
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• pp.679-695
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• 2024

This paper presents a novel technique that combines machine learning (ML) with moth-flame optimization (MFO) methods to predict the axial compressive strength (ACS) of concrete filled double skin steel tubes (CFDST) columns. The proposed model is trained and tested with a dataset containing 125 tests of the CFDST column subjected to compressive loading. Five ML models, including extreme gradient boosting (XGBoost), gradient tree boosting (GBT), categorical gradient boosting (CAT), support vector machines (SVM), and decision tree (DT) algorithms, are utilized in this work. The MFO algorithm is applied to find optimal hyperparameters of these ML models and to determine the most effective model in predicting the ACS of CFDST columns. Predictive results given by some performance metrics reveal that the MFO-CAT model provides superior accuracy compared to other considered models. The accuracy of the MFO-CAT model is validated by comparing its predictive results with existing design codes and formulae. Moreover, the significance and contribution of each feature in the dataset are examined by employing the SHapley Additive exPlanations (SHAP) method. A comprehensive uncertainty quantification on probabilistic characteristics of the ACS of CFDST columns is conducted for the first time to examine the models' responses to variations of input variables in the stochastic environments. Finally, a web-based application is developed to predict ACS of the CFDST column, enabling rapid practical utilization without requesting any programing or machine learning expertise.

• The Korean Journal of Pain
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• 제33권4호
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• pp.378-385
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• 2020

Background: The thoracic paravertebral block is an effective analgesic technique for postoperative pain management after breast surgery. The ultrasound-guided retrolaminar block (RLB) is a safer alternative to conventional paravertebral block. Thus, we assessed the analgesic efficacy of ultrasound-guided RLB for postoperative pain management after breast surgery. Methods: Patients requiring breast surgery were randomly allocated to group C (retrolaminar injection with saline) and group R (RLB with local anesthetic mixture). The RLB was performed at the level of T3 with local anesthetic mixture (0.75% ropivacaine 20 mL + 2% lidocaine 10 mL) under general anesthesia before the skin incision. The primary outcome was cumulative morphine consumption using intravenous patient-controlled analgesia (IV-PCA) at 24 hour postoperatively. The secondary outcomes were the visual analogue scale (VAS) scores at 1, 6, 24, and 48 hour postoperatively and the occurrence of adverse events and patient satisfaction after the surgery. Results: Forty-six patients were included, 24 in group C and 22 in group R. The cumulative morphine consumption using IV-PCA did not differ between the two groups (P = 0.631). The intraoperative use of remifentanil was higher in group C than in group R (P = 0.025). The resting and coughing VAS scores at 1 hour postoperatively were higher in group R than in group C (P = 0.011, P = 0.004). The incidence of adverse events and patient satisfaction was not significantly different between the two groups. Conclusions: A single injection of ultrasound-guided RLB did not reduce postoperative analgesic requirements following breast surgery.

• 동의생리병리학회지
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• 제19권1호
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• pp.92-97
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• 2005

Inhibition of inflammatory response, acceleration of basal cell growth, and balanced synthesis of extracellular matrix (ECM) are important in healing of cutaneous open wounds. In order to evaluate the healing effects of water extracts of Radix Astragali (the root of Astragalus membranaceus (Fisch.)) on open wound at early stage, the experimental open wounds were generated on the dorsal sides of SD rats under anesthesia. The boiled-water extracts of Radix Astragali $(100{\mu}l)$, soaked into an occlusive film dressing were applied once a day for eleven consecutive days. The healing process was assessed by measuring macroscopic appearance and wound areas of the open wounds. The molecular aspects of healing process by Radix Astragali extracts were also investigated by Hematoxylin-Eosin (H-E) double staining and immunohistological staining of collagen type I in the healed skin area, implying cell density and linear alignment of the granulation tissue, and ECM synthesis and its remodeling, respectively. The Astragali radix extracts were found to significantly accelerate the cutaneous wound healing by suppressing the inflammation and stimulating the basal cell growth in wounded area, as compared to epidermal growth factor (EGF).