• 펄프종이기술
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• 제41권5호
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• pp.26-32
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• 2009

As a part of utilizing the nanocellulose (NC) from lignocellulosic components of wood biomass, this paper reports preliminary results on the products of sulfuric acid hydrolysis. The purpose of this study was to investigate the morphology of both NC and micro-sized cellulose fiber (MCF) isolated by acid hydrolysis from commercial microcrystalline cellulose (MCC). Field emission.scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were employed to observe the acid hydrolysis suspension, NC, and MCF. The electron microscopy observations showed that the acid hydrolysis suspension, before separation into NC and MCF by centrifugation, was composed of nano-sized NCs and micro-sized MCFs. The morphology of isolated NCs was a whisker form of rod-like NCs. Measurements of individual NCs using TEM indicated dimensions of 6.96$\pm$0.87 nm wide by 178$\pm$55 nm long. Observations of the MCFs showed that most of the MCC particles had de-fibered into relatively long fibers with a diameter of 3-9 ${\mu}m$, depending on the degree of acid hydrolysis. These results suggest that proper technologies are required to effectively realize the potentials of both NCs and MCFs.

• 한국식품과학회지
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• 제48권2호
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• pp.178-186
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• 2016

이 연구는 일반식빵, 통밀빵, 그리고 생강나무 잎 추출물, 매생이 추출물, 매생이 냉동 건조물을 첨가한 통밀빵을 제조하고, 4중 동안 랫트에게 공급한 뒤 혈당과 혈중지방질 관련 지표에 미치는 영향을 조사하였다. 시험기간 동안 모든 통밀빵섭취 그룹에서의 체중증가는 일반식빵섭취 그룹과 비교하여 유의적으로 낮게 나타났으며, 음수, 식이 섭취량은 그룹간의 유의적인 차이를 보이지 않았다. 간과 신장의 무게, AST, ALP, ALT는 모든 그룹간의 유의적인 차이가 없는 것으로 보아 일반식빵과 통밀빵 식이제공은 간과 신장의 스트레스 증가와 무관함을 확인할 수 있었다. 공복혈당 수준은 NC 그룹은 1주차에서부터 4주차까지 혈당이 완만하게 상승했던 것에 비해 모든 통밀빵 그룹은 혈당 증가폭이 감소하는 경향을 나타내었다. 4주차에서는 모든 통밀빵 그룹은 NC 그룹과 비교하여 유의적인 차이를 보이며 혈당이 감소하는 것을 확인할 수 있었다. 경구당부하검사(OGTT)시 90분대 혈당치에서 모든 통밀빵 그룹은 NC 그룹($152.13{\pm}19.90mg/dL$)의 혈당치와 비교하여 유의적인 차이를 보이며 감소하는 것을 보여주었으며(p<0.05), AUC에서 WDC 그룹을 제외한 W 그룹, WL 그룹, 그리고 WC 그룹의 area value가 NC 그룹과 유의적인 차이를 보이며 적어졌다. WL 그룹과 WC 그룹의 경우 NC 그룹과 W 그룹과도 유의적인 차이를 보이며 면적이 감소하는 것을 확인하였다. 혈당 곡선아랫면적과 경구당부하 검사 결과를 종합해 볼 때 생강 추출물과 매생이 추출물이 첨가된 식빵은 일반식빵에 비해 내당능에 도움을 줄 수 있을 것으로 판단된다. 당화헤모글로빈의 함량을 측정한 결과 NC 그룹과 비교하여 모든 통밀빵 그룹에서 유의적인 차이를 보이며 함량이 감소하였고, 특히 WL 그룹과 WC 그룹은 W 그룹과도 유의적인 차이를 나타내며 당화 헤모글로빈 수치 관리에 좋은 효과를 나타내었다. 혈청 인슐린 농도를 측정하였을 때 모든 그룹에서 유의적인 차이를 보이지 않았으나 수치적으로 보았을 때 NC 그룹 대비 WL 그룹에서 39.9%, WC 그룹에서 37.2% 인슐린 함량이 증가하는 것을 확인하였다. 혈중 지방 질 지표를 측정한 결과 총 콜레스테롤과 LDL-콜레스테롤 수치에서는 그룹간 유의적인 차이를 나타내지 않았고, 중성지방의 경우 NC 그룹과 비교해 모든 통밀빵 그룹에서 유의적인 차이를 보이며 중성지방의 수치가 감소하였다. 혈중 HDL-콜레스테롤 수치는 WL 그룹이 NC 그룹과 유의적인 차이를 보이며 증가하는 것을 확인할 수 있었다. TBARS assy를 이용한 지방질과 산화 산물인 MDA를 측정한 결과 NC 그룹과 비교하여 모든 통밀빵 그룹에서 유의적인 차이를 나타내며 농도가 낮아졌고, WC 그룹에서 가장 낮은 수치를 나타내었다. 지방질과 관련된 유전인자인 $PPAR-{\alpha}$ mRNA 발현을 측정한 결과 모든 그룹간의 유의적인 차이는 나타나지 않았고, $PPAR-{\gamma}$ mRNA 발현의 경우 WL 그룹, WC 그룹에서 NC 그룹과 유의적인 차이를 나타내며 가장 적은 발현을 나타내었다. 이러한 결과를 미루어 보아 일반식빵에 비해 통밀빵을 섭취한 모든 그룹은 몸무게, 공복혈당, 경구당부 하 검사(OGTT), 당화헤모글로빈(HbA1c), 중성지방(TG), 동맥경화지수(AI) 측정 항목에서 통계적으로 유의적인 차이를 나타내었고 이것으로 통밀은 식빵 섭취시의 혈당 증가 완화 효과를 가지며 혈중 지방질수준 개선과 비만의 예방에 기여할 것으로 판단된다. 또한 생강나무 잎 추출물과 매생이 추출물을 첨가한 통밀빵 그룹은 당화헤모글로빈(HbA1c) 측정 항목에서 통밀빵 그룹과도 유의적인 차이를 나타내며 수치가 감소한 것으로 보아 통밀의 효능에 기능성 소재인 생강나무 잎과 매생이 추출물의 효능이 더 해지면서 상당한 혈당강하효과를 나타낸 것으로 판단된다.

• 한국생산제조학회지
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• 제9권2호
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• pp.102-111
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• 2000

Methodology of volumetric error identification and compensation is presented to improve the accuracy of NC machine tools by using a reference artifact and a touch trigger probe. Homogeneous transformation matrix and kinematic chain are used for modeling the geo-metric and thermal errors of a three-axis vertical machining center. The reference artifact is designed and fabricated to identify the model parameters by machine tool metrology. Parameters in the error model are able to be identified and updated by direct measurement of the reference artifact on the machine tool under the actual conditions which include the thermal interactions of error sources. A volumetric error compensation system based on IBM/PC is linked with a FANUC CNC controller to compensate for the identified volumetric error in machining workspace.

• 한국생산제조학회지
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• 제7권4호
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• pp.79-88
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• 1998

This study deals with the development of CAM system which can machine and measure any shape of mold and die by machining center and coordinate measureing machine . The overall goal of the CAM system is to achieve the mold and die machining , from digitizing through to final cutting. The hardware of the system comprises PC and machining center. CMM. There are three steps in the mold and die machining. (1) measuring of physical model by the CMM, (2) geometric modeling by the CAD system, (3) generation of NC code by the tool path compensated for tool radius. It is developed a software package, with which can conduct a micro CAM system in the PC without economical burden.

• 한국생산제조학회지
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• 제7권2호
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• pp.29-39
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• 1998

A conversational programming system for turning processes was studied to enhance the user friendliness of a NC Lathe by adopting man-machine interface functions through Delphi programming tool under the Windows 95 environment. Functions of tool collision checking were developed through zone limitation algorithms. Final shape of workpiece was generated by means of tree structure algorithm. Shop floor programming performance was incorporated in the developed CAM module. In order to increase flexibility of the man-machine interface, graphic based programming tools have been developed. A NC turning machine equipped with an open architecture PCNC was used as a test bed of the system. Performance of the system was verified through case studies.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 금형가공 심포지엄
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• pp.26-33
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• 2002

Die Factory follows typical order adaptive manufacturing, and delaying delivery affects directly product development of customer, Manufacturing Management System is tried to comply with the appointed date of delivery. It acquires running signal from NC milling, calculates manufacturing results, and offers the basic data to manage the operation ratio. Thus it offers Production data necessary to accomplish the objective of progress improvement for Unmanned Manufacturing. Manufacturing Management System runs on Web Environment, and is composed of electronic work order, operation ratio data acquisition and totaling module.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.306-307
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• 2006

The sinter-bonding behavior of iron based powder mixtures was investigated. To produce the green compacts to be joined the following powders based on $H{\ddot{o}}gan{\ddot{a}}s$ AB grade NC 100.24 plain iron powder were used: NC 100.24 as delivered, PNC 30, PNC 60 and NC 100.24 + 4%Cu powder mixtures. Dimensional behaviour of all those materials during the sintering cycle was monitored by dilatometry. Simple ring shaped specimens as the outer parts and cylindrical as the inner parts were pressed. The influence of parts' composition on joining strength was established. Diffusion of alloying elements: copper and phosphorous, across the bonding surface was controlled by metallography, SEM and microanalysis.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1105-1109
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• 2014

While single strand DNAs have been widely used for the scaffold of brightly fluorescent silver nanoclusters (Ag NCs), double strand DNAs have not been as successful. Herein, we report a novel synthetic approach for bright Ag NCs using branched double strand DNAs as the scaffolds for synthesis. X-shaped DNA (X-DNA) and Y-shaped DNA (Y-DNA) effectively stabilized Ag NCs, and both X-DNA and Y-DNA resulted in brightly fluorescent Ag NCs. The concentration and molar ratio of silver and DNA were found important for the fluorescence efficiency. The brightest Ag NC with the photoluminescence quantum efficiency of 19.8% was obtained for the reaction condition of 10 ${\mu}M$ X-DNA, 70 ${\mu}M$ silver, and the reaction time of 48 h. The fluorescence lifetime was about 2 ns for the Ag NCs and was also slightly dependent on the synthetic condition. Addition of Cu ions at the Ag NC preparations resulted in the quenching of Ag NC fluorescence, which was different to the brightening cases of single strand DNA stabilized Ag NCs.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.280-283
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• 1999

Square dies are widely used for hot extrusion processes with high production rate. However the design and manufacture of square dies mainly relies on experience of industrial engineers To overcome such difficulty this study develops a method of automatic generation of NC-codes for the manufacture of extrusion square dies. The result shows that the method can reduce the lead time for the design and manufacture of square dies as well as eliminating engineers ow experience.

• 한국생산제조학회지
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• 제8권6호
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• pp.119-125
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• 1999

This article proposes the analytical and experimental approaches for the reduction of vibration generated in the gear box of an NC machine. The lateral critical speed of main spindle and torsional natural frequencies were analyzed and the impact testing of gear box was performed. These results were compared with the forced operating speeds, The vibration was much diminished by redesign of gear module and reinforcement of box structure.