• International Journal of CAD/CAM
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• 제6권1호
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• pp.167-172
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• 2006

Recently, wire-EDM became a necessity for many engineering applications, particularly in the dies making. No-Core cut process is helpful for operations in which falling slug can jam the machine or wire. In this paper a proposed CAM system (called NCPP) is introduced, to overcome the limitations of the existing CAM systems in the machining of No-Core cut. The proposed CAM system (NCPP) provides pocketing of No-core cut and optimal selection of the position of starting hole (wire threading point), to minimize toolpath length. It was written for data exchange between CAD-CAM-CNC machines. This data model will become part of the ISO (Data model for Computerized Numerical Controllers) international standard. The NCPP system has been implemented in Visual C++. Many examples are used to illustrate NCPP system. The results show that, NCPP saves the machining time by significant value. This value depends on the shape and complexity of the workpiece that is being cut.

• 한국산림과학회지
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• 제99권2호
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• pp.220-225
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• 2010

This study was conducted to examine the effects of wound dressing with thiophanate-methyl paste on the compartmentalization of pruning wounds in Acer palmatum. A total of thirty field-grown trees were used for three different treatments, such as no dressing, dressing once right after pruning cut, and dressing twice, one more dressing treatment one year after initial dressing. Wound closure rate (WCR) and discolored/wound area ratio (D/W ratio) two years after treatment were measured. Variations of extractives, holocellulose and lignin at the treated branch unions were also examined. The WCR of no dressing treatment of 70.9% was significantly lower than those of the two dressing treatments (85.4% and 82.7%, respectively), while the difference between dressing once and twice was not significant. The D/W ratio of no dressing treatment (39.3%) was significantly higher than those of the two dressing treatments (around 30%). Generally, at the branch core of the treated union, contents of extractives and lignin were higher and holocellulose contents were lower than the branch core of the union with living branch. Among the branch core of treated union, no dressing treatment showed a relatively lower holocellulose (63.5%), and relatively higher extractives (2.8%) and lignin (26.6%) than dressing once (66.2%, 1.7%, 26.1%, respectively).

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.723-726
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• 2002

In this paper, a high efficiency leakage transformer for neon tube is developed to improve its power factor, to reduce its core loss and weight by using a technique of shape optimization and direction of grain-oriented silicon steel sheet. A protection circuit is designed for all types of neon transformer loaded with one or more neon lamps. Whenever the neon tube fails to be started up or comes to the life end, or encounters faults with open-circuits at the output terminals of the neon transformer, the protection circuit will be initiated to avoid more critical hazards. These neon transformers need a protection circuit to prevent from current stresses on circuit components by neon tube fail. The input of the transformer is automatically cut off when the abnormal condition occurs, preventing waste of no-load power. As the results of the study, the core weight is reduced by $11\%$, the power factor improved by $5\%$ and the efficiency increased by $6\%$ compared with the conventional type due to the employment of the grain-oriented steel sl)eel and the optimized core shape.

• The Journal of Advanced Prosthodontics
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• 제8권6호
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• pp.489-493
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• 2016

PURPOSE. This in-vitro study aimed to evaluate the fracture resistances and failure modes of endodontically treated mandibular premolars restored with endocrowns and conventional post-core retained crowns. MATERIALS AND METHODS. Thirty mandibular premolars were assigned into three groups (n=10): GI, intact teeth; GE, teeth with endocrowns; GC, teeth with conventional post-core supported crowns. Except for the teeth in group GI, all specimens were cut to 1.5 mm above the cementoenamel junction and endodontically treated. Both endocrowns and conventional crowns were fabricated from lithium-disilicate blocks using a CEREC 3D CAD/CAM unit. All specimens were subjected to thermocycling and then to $45^{\circ}$ oblique compressive load until fracture occurred. The fracture resistance and failure mode of each specimen were recorded. Data were analyzed with one-way ANOVA and LSD Post Hoc Test (${\alpha}=.05$). RESULTS. The fracture resistances of GE and GC were significantly lower than that of GI (P<.01), while no significant difference was found between GE and GC (P=.702). As of the failure mode, most of the specimens in GE and GC were unfavorable while a higher occurrence of favorable failure mode was presented in GI. CONCLUSION. For the restoration of mandibular premolar, endocrown shows no advantage in fracture resistance when compared with the conventional method. Both of the two methods cannot rehabilitate endodontically treated teeth with the same fracture resistances that intact mandibular premolars have.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 학술대회 논문집
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• pp.151-155
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• 2005

지금까지의 핵융합 장치는 자기우물과 열역학을 바탕으로 한 토카막 장치가 수소핵융합을 하였으나 고온의 플라스마를 장시간 동안 가둠이란 현실적으로 불가능하여 성공사례가 없었다. 본 핵융합 촉진 방법을 이용한 새로운 핵융합 장치는 토카막 장치의 토로이달 자기장용 알루미늄코일 내에 토러스 철심 C형 Core Block과 토로이달 알루미늄코일을 넣어 토로이달 자기장을 모으고 토로이달 전류 흐르도록 하여 토러스 Core의 일부가 절개된 간극사이에 핵융합로를 배치하고 융합원료(전해액)를 토로이달 전류로 전기분해 한다. 전원과 토로이달 자계용 코일, 토로이달 코일 융합원료로 직렬회로로 이루어져 있어 토로이달 전류는 필라멘트 전류로 되어 융합원료에 투입된다. 필라멘트 전류사이에는 자기흡입력이 외부의 입력전력으로 계속 증대되어 쿨롱에 힘을 넘어 핵융합에 이르고 그로인해 질량결손이 생겨 아인슈타인의 질량에너지$(E=mC^2)$가 빛에너지와 열에너지로 방출됨을 확인했다.

• 한국자기학회지
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• 제5권5호
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• pp.833-836
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• 1995

A capacitor discharge impulse magnetizer is used to produce a high current pulse of short duration in a magnetizing fixture for magnets of the various shapes. The problem of designing custom fixtures for magnetization has often been considered more of conventional experience than a scientific theory. Therefore, the design of magnetizingfixture has until recently been a "cut and try" process. It was common to literally blow up one or more fixtures beforeachieving the desired results. Finite element CAD package allow the design of such a fixture. Since magnetizing fixtures come in a variety of sizes and shapes, there is usually no simple analysis method that can be used to estimate the field characteristics of the fixtures. Instead, one typically uses finite element analysis. FEA program MAXWELL is the primary tool used here. The purpose of this study was a examine both theoretically and experimentally the field characteristics inside the fixture. Independent of sizes and shapes of magnetizing fixtures, the desired magnetic field can be obtained with resonable predictability. The experimental results have been achieved using a 1000[V], 22.4[KJ] capacitor discharge magnetizer and iron-core fixtures.

• Journal of the Korean Wood Science and Technology
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• 제47권5호
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• pp.547-556
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• 2019

Thinned, small larch logs have small diameters and no value-added final use, except as wood chips, pallets, or fuel wood, which are products with very low economic value; however, their mechanical strength is suitable for structural applications. In this study, small larch logs were sawed, dried, and cut into square timbers (with a $90mm{\times}90mm$ cross section) that were laterally glued to form core panels used to manufacture cross-laminated timber (CLT) wall panels. The surface and back of these core panels were covered with 12-mm-thick structural plywood panels, used as cross bands to obtain three-ply CLT wall panels. This attachment procedure was conducted in two different ways: gluing and pressing (CGCLT) or gluing and nailing (NGCLT). The size of the as-manufactured CLT panels was $1,220mm{\times}2,440mm$, the same as that of the plywood panels. The final wall panels were tested under lateral shear force in accordance with KS F 2154. As the lateral load resistance test required $2,440mm{\times}2,440mm$ specimens, two CLT wall panels had to be attached in parallel. In addition, the final CLT panels had tongued and grooved edges to allow parallel joints between adjacent pieces. For comparison, conventional light-frame timber shear walls and midply wall systems were also tested under the same conditions. Shear walls with edge nail spacing of 150 mm and 100 mm, the midply wall system, and the fabricated CGCLT and NGCLT wall panels exhibited maximum lateral resistances of 6.1 kN/m (100%), 9.7 kN/m (158%), 16.9 kN/m (274%), 29.6 kN/m (482%), and 35.8 kN/m (582%), respectively.

• 구강회복응용과학지
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• 제16권1호
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• pp.51-60
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• 2000

주조 포스트코아와 치질 계면에서 시멘트 종류에 따른 미세누출의 변화를 알아보기 위해 상악 전치부 및 하악 견치, 총 40개의 단근치를 백악-법랑 경계 2mm 상방에서 절단하고 백악-법랑 경계 1mm 상방에 chamfer 변연 형성 후, 통상적 근관 형성, 및 충전을 시행하고 주조용 Parapost를 이용하여 40개의 주조 포스트코아를 제작하였다. 각 군당 10개씩 4군으로 분배하여, 실험 I군에서는 인산아연 시멘트인 Fleck's를, 실험 II군에서는 글래스아이오노머 시멘트인 Fuji I을, 실험 III군에서는 4-META계 레진 시멘트인 Superbond C & B를, 실험 IV군에서는 인산 에스테르계 레진 시멘트인 Panavia 21로 각각 접착한 다음, 500회 thermocycling 및 1% basic fuchsin 염색액 침액을 거친 후 시편을 협설면으로 절단하고 광학 현미경상에서 포스트와 치질 계면사이의 미세누출정도를 지수로 산정하여 시편 협설면의 지수 평균을 계산한 후 각 군간의 비교 분석을 통해 다음과 같은 결론을 얻었다. 1. 모든 시편의 계면에서 미세누출이 관찰되었다. 2. 실험 I군에서 실험 II군, 실험 III군, 및 실험 IV군에 비해 유의성있게 가장 높은 미세누출지수를 보였고, 실험 II군에서 실험 III군, 및 실험 IV군에 비해 유의성있게 높은 미세누출지수를 보였다(p<0.05). 3. 실험 IV군에서 가장 낮은 미세누출지수를 보였으나 실험 III군과의 통계학적 차이는 없었다(p>0.05).

• 한국초지조사료학회지
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• 제16권4호
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• pp.315-326
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• 1996

An experiment was carried out to determine effect of cultivar, drying agent concentration and preservative on the moisture content, temperature and quality changes of fall harvested oat(Avena sativa L.) hay during field curing and storage. The main plots consisted of the cultivar such as 'Foothill' and 'Swan', the subplots consisted of drying agent concentration such as 7Skg/ha(C1), lOSkglha(C2) and control(C0) and the sub-subplots consisted of preservative such as buffered acid(BA), lactic bacteria inoculant(LB) and control(C0). Moisture contents of 'Foothill' and 'Swan' oat cultivar at harvest were 635.5 and 385.4%DW(Dry weight), respectively, but the final moisture contents of the oat cultivars were 117 and 86%DW. The moisture content of cut oat was not affeded by drying agent concentration. Core temperature of baled 'Swan' oat hay was a little higher than that of 'Foothill' and no consistent preservative effect was found. Total nitrogen content of 'Swan' oat hay was 3.08% and that of 'Foothill' oat hay was 3.45%(P<0.05). Drying agent treatment increased total nitrogen content of 'Swan'(P <0.05), but preservative had no effect. Crude fiber content of oat cultivar was increased as the curing progressed(P<0.05) and the difference of crude fiber content of oat cultivar was maintained through the whole curing period. Effect of drying agent concentration on crude fiber content was not found after preservation. Crude fiber content of 'Swan' oat hay was higher than that of 'Foothill' by 1.O% in ADF and 3.1 % in NDF(P<0.05). No preservative effect was found in crude fiber content. According to RFV of oat cultivar at harvest, forage quality of 'Foothill' and 'Swan' was Prime and Grade 1, respectively, but that of both cultivm was above Grade 2 at the final curing day. RFV of the stored 'Foothill' and 'Swan' oat hay was 122 and 114(P<0.05), respectively, and the quality of oat hay was classified as Grade 1 and 2, respectively, according to the forage quality standard assigned by AFGC.

• 대한치과보철학회지
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• 제47권1호
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• pp.53-60
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• 2009

연구목적: 오늘날 심미적 요구의 증가로 치아색 포스트 코어에 대한 많은 관심이 모아지고 있으며 다양한 연구가 진행 중이다. 현재 화이버 포스트 (ParaPost fiber White, Coltene Whaledent, Cuyahoga Falls, USA), 지르코니아 포스트 (CosmoPost, Ivoclar Vivadent, Schann, Germany) 등에 관한 논문은 다소 나와 있으나 요즘 여러 분야에서 관심을 받고 있는 CAD/CAM (computer-aided design/computer-aided manufacturing) 방식으로 지르코니아를 가공한 절삭형 지르코니아 포스트 코어에 대한 연구는 많지 않은 실정이다. 이 연구의 목적은 CAD/CAM을 이용한 지르코니아를 비롯하여 근관치료된 치아에서 사용된 세 가지 다른 치아색 포스트 코어에 대해 미세누출 (microleakage)을 비교해 보는 것이다. 연구 재료 및 방법: 발치된 건전한 상악 절치 27개를 채택하여 백악법랑질경계 (CEJ)에서 절단하여 근관치료를 시행하고, 세군 (각 9개)으로 나누었다. 각군들은 화이버 포스트와 콤포짓트 레진 코어 (1군), 지르코니아 포스트와 열가압형 세라믹 코어 (2군), CAD/CAM 절삭형 지르코니아 포스트 코어 (3군)로 수복하였다. $5-55^{\circ}C$ 1000회 열순환 처리 (thermocycling)를 시행하고, 2% 메틸렌 블루로 $37^{\circ}C$에서 24시간 염색하였다. 치아장축과 평행하게 순설방향으로 절단하여 미세누출을 현미경과 컴퓨터 프로그램을 사용하여 분석을 하였다. 데이터는 one-way ANOVA와 Scheffe's multiple range test (${\alpha}=0.05$)로 분석하였다. 결과: 모든 군에서 미세누출을 보였으며, 지르코니아 포스트와 열가압형 세라믹 코어군 (2군)에서 치근계면 입구에서는 다소 많은 미세누출을 보였으나 포스트 끝에 이르러서는 거의 미세누출이 없는 결과를 보였다. 화이버 포스트와 콤포짓트 레진 코어군 (1군)과CAD/CAM 절삭형 지르코니아 포스트 코어군 (3군)에서는 부위별로 균등한 미세누출을 보였다. 결론: 화이버 포스트와 콤포짓트 레진 코어군, 지르코니아 포스트와 열가압형 세라믹 코어군, CAD/CAM 절삭형 지르코니아 포스트 코어군 모두에서 미세누출을 보였고, 이 중에서 지르코니아 포스트와 열가압형 세라믹 코어군이 좀 더 큰 미세누출에 대한 저항성을 보였으며 화이버 포스트와 콤포짓트 레진 코어군, CAD/CAM 절삭형 지르코니아 포스트 코어군은 유사한 양상을 보였으나, 각 실험군 간에 통계적으로 유의한 차이는 인정되지 않았다. (P>.05)