• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.699-706
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• 2016

Partial discharges (PD) lead to the degradation of high voltage cables and accessories. PD activities occur due to the existence of impurities, voids, contaminants, defects and protrusions during the manufacture and installation of power cables. Commonly, insulation failures occur at cable joints and terminations, caused by inhomogeneous electric field distributions. In this work, a blend of natural rubber (NR) and linear low density polyethylene (LLDPE) was investigated, and the optimal formulation of the blend that could resist PD was discussed. The experiments were conducted under a constant high voltage stress test of 6.5 kV AC and the magnitude of partial discharge activities was recorded using the CIGRE method II. Pattern analysis of PD signals was performed along with the interpretation of morphological changes. The results showed that the addition of 10 wt% of NR and 5 wt% of Alumina Trihydrate (ATH) provided promising results in resisting PD activities. However, as the NR content increased, more micropores existed, thus resulting in increased PD activities within the samples.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.494-494
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• 2000

This paper demonstrates that the largest Lyapunov exponent $\lambda$ of recurrent neural networks can be controlled by a gradient method. The method minimizes a square error $e_{\lambda}=(\lambda-\lambda^{obj})^2$ where $\lambda^{obj}$ is desired exponent. The $\lambda$ can be given as a function of the network parameters P such as connection weights and thresholds of neurons' activation. Then changes of parameters to minimize the error are given by calculating their gradients $\partial\lambda/\partialP$. In a previous paper, we derived a control method of $\lambda$via a direct calculation of $\partial\lambda/\partialP$ with a gradient collection through time. This method however is computationally expensive for large-scale recurrent networks and the control is unstable for recurrent networks with chaotic dynamics. Our new method proposed in this paper is based on a stochastic relation between the complexity $\lambda$ and parameters P of the networks configuration under a restriction. Then the new method allows us to approximate the gradient collection in a fashion without time evolution. This approximation requires only $O(N^2)$ run time while our previous method needs $O(N^{5}T)$ run time for networks with N neurons and T evolution. Simulation results show that the new method can realize a "stable" control for larege-scale networks with chaotic dynamics.

• Composites Research
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• 제12권2호
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• pp.26-35
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• 1999

모달변형에너지법과 조화진동해석법을 이용하여 겹침이음부와 부분층댐버를 갖는 보에 대해 유한요소모델을 설정하고 진동감쇠특성을 연구하였다. 모달변형에너지법과 조화진동해석법으로 구한 계의 공진주파수와 손실계수는 거의 같은 값ㅇ르 보였으며, 형상의 변화에 따른 손실계수 변동경향은 이론해석에 의한 결과와 유사하였다. 부분층댐퍼의 위치, 점탄성층과 보강탄성층의 두께 및 탄성계수의 변화가 계의 손실계수에 미치는 영향을 파악하였으며, 점탄성층의 손실계수변화에 따른 영향도 검토하였다. 이들 결과로부터 계의 감쇠효과를 극대화하기 위한 구조물의 형상 및 물성조건을 제시하였다.

• 한국포장학회지
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• 제6권1호
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• pp.31-36
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• 2000

10개월 숙성된 전통 된장과 고추장을 232 mL의 유리병 용기에 포장조건을 다르게 하여 각각 180g과 150g씩 포장하고, $13^{\circ}C$에서 저장하면서 포장내의 기체조성, 색택, 총산, pH 등의 품질변화를 측정하였다. 포장 처리구로서는 핀홀을 장착시켜서 통기성을 준 경우와 $CO_2$ 흡수제로서 $Ca(OH)_2$를 장착시킨 경우에 대하여 실험하였다. 된장과 고추장 모두에서 대조구 밀봉포장은 저장중 높은 $CO_2$ 분압의 증가를 일으키고 $O_2$ 분압의 감소소멸를 나타내나, 질소분압은 비교적 일정한 수준에서 유지하여 높은 압력을 발생시켰다. 반면에 $Ca(OH)_2$ 함유포장에서는 저장 70일 부근까지 비교적 낮은 $CO_2$ 분압를 유지하여서 큰 압력 발생 없이 저장이 가능하였다. 핀흘을 장착시킨 통기성 포장에서는 $O_2$ 분압과 $N_2$ 분압이 감소하고 $CO_2$ 분압은 계속 상승한 후, 완만히 감소하였다. 이러한 포장내의 기체조성의 변화는 장류의 품질변화에 영향을 미쳐서 핀홀을 가진 포장에서 그 변화의 정도가 상대적으로 약간 작았으나, 된장 포장의 경우 저장 120일 이후에 곰팡이 오염과 성장의 문제점을 가지고 있었다. 저장 70 여일 후에 측정한 미생물 군집의 변화에서는 포장간에 뚜렷한 차이를 발견할 수 없었다. 핀홀 포장은 저장 전기간동안 포장내에 압력 발생 없이 낮은 $O_2$ 농도와 높은 $CO_2$ 농도를 유지하여 상대적으로 작은 품질변화를 얻을 수 있는 것으로 평가되나 냄새유출과 외부로부터의 오염 문제의 해결을 필요로 한다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권3호
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• pp.160-165
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• 2012

Objectives: This study evaluated the clinical results of partial sublingual glandectomy accompanying the excision of ranula as new treatment modality. Materials and Methods: A total of 43 patients who were treated between 1999 and 2007 for oral or plunging ranula were reviewed. All patients were treated surgically by various methods with a total of 55 different procedures performed. Ten cases of partial sublingual glandectomy with excision of the ranula were conducted. All excised specimens were examined. We compared the clinical outcomes resulting from each treatment method. Results: The recurrence rates for marsupialization, excision of ranula, marsupialization with gauze packing, total excision of sublingual gland and ranula, and partial sublingual glandectomy with excision of ranula were 50%, 25%, 25%, 0% and 10%, respectively. Of the 10 patients treated by partial sublingual glandectomy with ranula excision, only one experienced recurrence (10%), i.e., plunging ranula. None of the ranulas contained an epithelial lining, and the excised portion of the feeding sublingual glands showed degenerative changes. Conclusion: In removal of ranulas, we found that excision of the attached sublingual gland, which removed the feeding portion and degenerative acinar cells, yielded good outcomes. Thus, as a new conservative method for treatment, we recommend partial sublingual glandectomy to accompany excision of the ranula.

• Journal of Microbiology and Biotechnology
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• 제22권2호
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• pp.274-282
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• 2012

The object of this study was to assess the efficacy of Polycan from Aureobasidium pullulans SM-2001, which is composed mostly of beta-1,3-1,6-glucan, on osteoarthritis (OA)-induced by anterior cruciate ligament transection and partial medial meniscectomy (ACLT&PMM). Three different dosages of Polycan (85, 42.5, and 21.25 mg/kg) were orally administered once a day for 84 days to male rats a week after ACLT&PMM surgery. Changes in the circumference and maximum extension angle of each knee, and in cartilage histopathology were assessed using Mankin scores 12 weeks after Polycan administration. In addition, cartilage proliferation was evaluated using bromodeoxyuridine (BrdU). As the result of ACLT&PMM, classic OA was induced with increases in maximum extension angles, edematous knees changes, and capsule thickness, as well as decreases in chondrocyte proliferation, cartilages degenerative changes, and loss of articular cartilage. However, these changes (except for capsule thickness) were markedly inhibited in all Polycan- and diclofenac sodium-treated groups compared with OA control. Although diclofenac sodium did not influence BrdU uptake, BrdU-immunoreactive cells were increased with all dosages of Polycan, which means that Polycan treatment induced proliferation of chondrocytes in the surface articular cartilage of the tibia and femur. The results obtained in this study suggest that 84 days of continuous oral treatment of three different dosages of Polycan led to lesser degrees of articular stiffness and histological cartilage damage compared with OA controls 91 days after OA inducement, suggesting that the optimal Polycan dosage to treat OA is 42.5 mg/kg based on the present study.

• Applied Microscopy
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• 제17권1호
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• pp.115-130
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• 1987

The present experiment was performed to investigate the acute effects of cadmium on ultrastructural and biochemical changes in mouse kidney and compare these changes with liver damage. Mouse were injected with cadmium chloride at a dose of 5 mg/kg body weight. After treatment, mouse were sacrificed at time intervals of 6, 12, 24 and 48 hours. It was observed that ultrastructural changes in mouse kidney were composed of swelling of mitochondria, dilation in endoplasmic reticulum, wrinkling at basal infolded membrane, formation of autophagosome and partial loss of microvilli in brush. border, and that ultrastructural changes in liver were mitochondrial change, dilation and deterioration of rough endoplasmic reticulum and proliferation of smooth endoplasmic reticulum. Biochemical effects of cadmium were more severe on liver than kidney. Therefore, acutely injected cadmium caused not only liver damage, but also kidney damage.

• Journal of Photoscience
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• 제9권2호
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• pp.326-328
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• 2002

In many plant cells, the positions of chloroplasts change in response to changes in light conditions. In the epidermal cells of the aquatic angiosperm Vallisneria gigantea, the avoidance response of chloroplasts is induced specifically by irradiation with blue light of high intensity. Possible roles of actin cytoskeleton in the blue-light-induced avoidance response of chloroplasts were investigated by partial irradiation and phalloidin staining. We showed that the blue-light-dependent redistribution of chloroplasts was induced only in the limited area, where exposed to blue light, even in individual cells. In addition. in the exposed area, the configuration of actin filaments strikingly changed compared with that before the irradiation. Short and thick bundles of actin filaments surrounding the chloroplasts changed to much longer and thinner bundles with a more stretched array. In contrast, in the unexposed area, neither the distribution of chloroplasts nor the configuration of actin filaments exhibited any changes. Cytochalasin D and latrunculin B inhibited the avoidance response of chloroplasts concomitantly with the fragmentation of actin filaments. These results indicate that the reorganization of actin filaments plays a crucial role in the induction of avoidance response of chloroplasts.

• 대한수의학회지
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• 제38권4호
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• pp.936-945
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• 1998

This study was performed to investigate the best surgical technique for normal stifle mobility by comparison with clinical signs and histopathological changes of articular cartilage after femoral trochleoplasty, trochlear chondroplasty and trochlear wedge recession. Twelve small mixed dogs who had grade I or II medial patellar luxation were used. The days that the dog had partial and full weight bearing were checked and histopathological changes 49 and 90 days after surgery were observed. The dogs had partial weight bearing in 3~6 days postoperatively and full weight bearing in 20~24 days. After femoral trochlepoplasty, the articular surface was irregular and rough, but smooth after trochlear chondroplasty and trochlear wedge recession. Histopathologic examination performed on the 49th and 90th days after femoral trochleoplasty revealed that articular surface was occupied by fibrocartilage but the hyaline cartilages are preserved after trochlear chondroplasty and trochlear wedge recession. In trochlear wedge recession, the wedges of all cases were firmly attached to underlying subchondral bone which were indicating complete healing. The results of this study suggested that the trochlear wedge recession was the best chondroplasty for correcting patellar luxation.

• 대한수의학회지
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• 제34권4호
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• pp.653-664
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• 1994

This study was carried out to investigate diabetic renal changes in cyclophosphamide(CY) treated nonobese diabetic(NOD) mice and to develop animal model of diabetic human nephropathy. The 8-week-old NOD and ICR mice were injected with cyclophosphamide intraperitoneally at 200mg/kg body weight and compared the chemical effects on these mice with the non-treated NOD and ICR mice respectively. The renal glomeruli in ICR, cyclophosphamide-treated ICR(ICR+CY), NOD and cyclophosphamide-treated NOD(NOD+CY) mice were observed by the light and electron microscopes. The results obtained were summarized as follows ; 1. Spontaneous incidences of diabetes mellitus in NOD mice were significantly promoted by dosing with cyclophosphamide. 2. Glomerulohypertrophy, proliferation of mesangium, partial thickening of glomerular basement membrane, and partial fusion of pedicels of podocyte were observed in NOD mice and NOD+CY mice. These changes were not observed in both ICR mice and ICR+CY mice. 3. The diabetic nephropathy observed in NOD+CY mice was more severe than that of non-treated NOD mice.