• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.38-46
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• 1999

Spindle motor current is used to estimate the cutting force indirectly and control the feed rate for the cutting force regulation. The proposed algorithm is implemented to a DSP board based hardware for the industrial application. The software to make POP terminal communicate with the DSP board and POP server is coded under Windows 95 environment. Experiments under varying cutting conditions show that the DSP board recognizes the information of installed cutting tool and cutting conditions delivered from the POP server to use them for the proper control of the feed rate. The cutting force is regulated well during machining of tapered or stepped workpiece and circular shaped workpiece as well.

• 한국정밀공학회지
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• 제27권2호
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• pp.20-24
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• 2010

High speed cutting processes of rigid flexible printed circuit board by making use of high power UV laser with nano-second pulse width have been proposed and investigated experimentally. Also robust laser cutting system has been designed and developed in order to obtain a good cutting quality of rigid and flexible PCB with multi-layers (2-6 layers). Power controller module developed for ourselves is adapted to control the laser output power in the range less than 1%. The systems show the good performance of cutting speed, cutting width and cutting accuracy, respectively. Especially we have confirmed that the short circuit problem due to the carbonized contamination occurred in cross section of multi-layers by thermal effect of high power laser has been improved largely by using multi-pass cutting process with low power and high speed.

• 한국생산제조학회지
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• 제22권1호
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• pp.56-62
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• 2013

The laser cutting process which is flexible and rapid usually provides a better result in cutting of flexible printed circuit boards (FPCB). However, circuit-short by the re-deposition of debris from laser ablation or its heat affect zone (HAZ) on the cutting surfaces can be a problem. A laser cutting process of FPCB in the presence of liquid can minimize these negative effects. The temperature distribution of copper and polymer parts of FPCB was analyzed with numerical simulation and the experimental results were presented to evaluate this process. Generally, laser cutting under liquid has advantages of less re-deposition of carbides and less HAZ on the cutting edges. However, bubble generation and laser beam control through the liquid media should be considered carefully to obtain a successful result.

• 한국식생활문화학회지
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• 제1권3호
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• pp.211-218
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• 1986

본 김치용 도마는 현재 널리 쓰이고 있는 일반 도마를 이용하여 김치와 같이 국물이 많은 식품을 절단 할 때 국물이 유출되므로써 야기되는 오염을 최소화 할 목적으로 제작된 도마이다. 이 도마의 기능적 특징은 절단시 유출된 국물이 사방으로 흐르지 않고 일차적으로 세로 경사면을 따라 흐른 다음 이차적으로 가로 경사골을 따라 국물이 김치 그릇에 흘러 내리게 되어 있어서 김치도마의 오염 넓이가 작게됨은 물론 작업테이블 및 작업장 바닥에 오염을 발생시키지 않고, 김치 그릇에 모아 떨어지게 하는 기능성을 갖인 2차원적 흐름기능을 발휘한다. 또한 본 김치용 도마는 일반적인 평면 도마에 비하여 모양이 둥근 식품이 둥굴어 떨어짐 방지기능이 있고, 사용 후 건조 속도가 빨라 위생적이며, 또한 계량적으로 식품을 절단 할 수 있음은 물론 절단시 손을 배는 위험을 적게하는 기능성이 있다. 따라서 본 도마는 김치 문화의 세계화에서 김치의 바람직한 동반자가 될 것으로 생각된다.

• 한국수산과학회지
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• 제33권6호
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• pp.524-528
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• 2000

식품중에 오염된 Listeria monocytogenes의 열감수성에 미치는 각종 첨가물의 영향과 식품의 처리 가공시에 수반되는 조리기구 수세나 염소, 자외선, 열탕 등 각종 소독처리의 효율성을 확인하였다. 키토산, 솔빈산칼륨 둥은 시험균주 L. monocytogenes H-12의 열 감수성 증대에 유의할 만한 영향을 미치지 못하였으나, 명태 연육에 중합인산염을 $1{\%}$ 첨가할 경우 시험균주의 열감수성은 뚜렷히 증가되었다. 시험균주 L. monocytogenes H-12가 $약 10^4{\~}10^5/cm^2$ 되도록 오염시킨 나무, 플라스틱, 스테인레스 재질의 도마를 흐르는 수도수로 세척하였을 때 스테인레스 도마나 플라스틱 도마의 경우 각각 10초 및 1분 후에는 균이 검출되지 않았으나, 나무 도마에서는 거의 제균효과가 없었다. 스테인레스 및 플라스틱 재질의 도마를 $5{\~}50 ppm$의 염소용액에 10초간 침지하고 수세할 경우 오염균의 제거가 가능하였으나, 나무 도마의 경우 100ppm 염소용액으로 처리하여도 균 수의 감소는 거의 없었다. 15W의 자외선을 30cm 거리에서 시험균주로 오염된 각 재질의 도마에 조사할 경우 스테인레스 및 플라스틱 도마의 경우 5분간 조사 후에는 균이 검출되지 않았으나, 나무 도마에서는 60분 처리 후에도 균이 검출되었다. 각종재질의 조리용 도마에 오염된 시험균주 L. monocytogenes H-12의 열탕처리에 의한 제균조건은 $70^{\circ}C$, 10초 이상으로 확인되었다.

• 한국식품위생안전성학회지
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• 제16권2호
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• pp.96-102
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• 2001

위생적인 신선육 처리 방안을 모색하기 위하여 도체처리 과정과 식육처리 과정 중 고기의 표면 및 작업도구의 위생실태를 계절별로 검토하였다. 하절기에 총균수, 저온성 균수, 대장균군수 모두 높게 나타났으며, 특히 도체 세척전보다 세척 후에 미생물 오염도가 높았고, 계절에 관계없이 수송 후의 오염도가 가장 높았다. 칼, 도마와 장갑에서 하절기에 $10^{5}$ $ extrm{cm}^2$을 나타내어 높은 미생물 오염도를 나타내었다. 도체 처리 과정 중 도체 표면에서 Escherichia. coli O157, Pseudomonas aeruginosa, Klebsiella, ornithinolytica, Staphylococcus aureus, E. Tatumella, ptyseos, Serratia odorifera, Aeromonas, Aeromonas sobria, Enterobacter colacae, Flavimonas oryzihabitans oryzihabitans를 분리하였으며, 도마에서는 S. aureus, Listeria grayi, L. monocytogenes, 장갑에서 L. grayi, Erwinia spp., Salmonella spp. S aureus, 골발육에서는 Citrobacter freundii, L. momocytogenes, S. aureus가 분리.동정하였다.

• 한국정밀공학회지
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• 제27권10호
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• pp.23-28
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• 2010

Resistance trimming and cutting processes of printed circuit board by making use of high power UV laser with nano-second pulse width have been proposed and investigated experimentally. Also laser-based application system with high flexibility and complex has been designed and adopted power controller, auto beam size control, auto-focusing and control program developed for ourselves. The function of each module shows that they can be reliable for industrial equipments. Resistance trimming method used a plunge and double cut process with $20{\mu}m$ spot size beam. Results show that double cut process is more effective to control resistance trimming in precision than plunge cut process.

• Journal of Animal Science and Technology
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• 제62권6호
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• pp.912-921
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• 2020

We examined the rates of pathogenic bacterial cross-contamination from gloves to meat and from meat to gloves during pork processing under meat-handling scenarios in transfer rate experiments of inoculated pathogens. The inoculated pork contained ~5-6 Log10 CFU/g pathogenic bacteria like Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), and Salmonella enterica subsp. enterica (Sal. enteritidis). On cotton gloves, after cutting the pork, the cutting board, knife, and cotton gloves showed 3.07-3.50, 3.29-3.92 and 4.48-4.86 Log10 CFU/g bacteria. However, when using polyethylene gloves, fewer bacteria (3.12-3.75, 3.20-3.33, and 3.07-3.97 Log10 CFU/g, respectively) were transferred. When four pathogens (6 Log10 CFU/g) were inoculated onto the gloves, polyethylene gloves showed a lower transition rate (cutting board 2.47-3.40, knife 2.01-3.98, and polyethylene glove 2.40-2.98 Log10 CFU/g) than cotton gloves. For cotton gloves, these values were 3.46-3.96, 3.37-4.06, and 3.55-4.00 Log10 CFU/g, respectively. Use of cotton gloves, polyethylene gloves, knives and cutting boards for up to 10 hours in a meat butchering environment has not exceeded HACCP regulations. However, after 10 h of use, 3.09, 3.27, and 2.94 Log10 CFU/g of plate count bacteria were detected on the cotton gloves, cutting board, and knives but polyethylene gloves showed no bacterial count. Our results reveal the transfer efficiency of pathogenic bacteria and that gloved hands may act as a transfer route of pathogenic bacteria between meat and hands. The best hand hygiene was achieved when wearing polyethylene gloves. Thus, use of polyethylene rather than cotton gloves reduces cross-contamination during meat processing.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.141-146
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• 2002

Real-time monitoring and control of the cutting force is essential for unmanned cutting process. Although the cutting force can be measured directly using tool dynamometers, their implementation is not feasible in industry due to high cost. Alternative approach is the cutting force estimation based on spindle drive models, but it requires the knowledge of their characteristics with the spindle speed variation. This paper investigates the power-factor and frictional characteristics of three-phase induction motors and determines its characteristics below and above the base speed, respectively. In order to realize the proposed cutting force monitoring system, a stand-alone DSP board was utilized. Its monitoring and control performance is evaluated in a CNC lathe.

• 한국축산식품학회지
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• 제32권1호
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• pp.62-67
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• 2012

This study calculated kinetic parameters of Escherichia coli O157:H7 and developed a probabilistic model to estimate growth probabilities of E. coli O157:H7 on polyethylene cutting boards as a function of temperature and time. The surfaces of polyethylene coupons ($3{\times}5$ cm) were inoculated with E. coli O157:H7 NCCP11142 at 4 Log $CFU/cm^2$. The coupons were stored at 13 to $35^{\circ}C$ for 12 h, and cell counts of E. coli O157:H7 were enumerated on McConkey II with sorbitol agar every 2 h. Kinetic parameters (maximum specific growth rate, Log $CFU/cm^2/h$; lag phase duration, h; lower asymptote, Log $CFU/cm^2$; upper asymptote, Log $CFU/cm^2$) were calculated with the modified Gompertz model. Of 56 combinations (temperature${\times}$time), the combinations that had ${\geq}$0.5 Log $CFU/cm^2$ of bacterial growth were designated with the value of 1, and the combinations that had increases of <0.5 Log $CFU/cm^2$ were given the value 0. These growth response data were fitted to the logistic regression to develop the model predicting probabilities of E. coli O157:H7 growth. Specific growth rate and growth data showed that E. coli O157:H7 cells were grown at $28-35^{\circ}C$, but there were no obvious growth of the pathogen below $25^{\circ}C$. Moreover, the developed probabilistic model showed acceptable performance to calculate growth probability of E. coli O157:H7. Therefore, the results should be useful in determining upper limits of working temperature and time, inhibiting E. coli O157:H7 growth on polyethylene cutting board.