• 경영과학
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• 제16권1호
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• pp.137-156
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• 1999

Flexibility is a competitive weapon in the changing environment. In order to pursue the flexibility, Korean manufacturing companies must define the flexibility dimension clearly, build the appropriate manufacturing infrastructures and measure the right flexibility performance indicators. This paper found out as follows. First, Korean manufacturing companies' flexibility strategy groups were formed three types. They are flexibility superior group, middle flexibility group and flexibility inferior group. Second, when different types of flexibility strategy group measured their performances, the degree of importance of flexibility performance indicators were different among groups. Third, when different types of flexibility strategy group were pursued, the different manufacturing methods such as product/process design technology, analysis technology, production system management technology and non technological factors were used. Lastly, when different types of flexibility strategy group were pursued, the actual flexibility performances were different among groups.

• Macromolecular Research
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• 제11권3호
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• pp.157-162
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• 2003

6FDA-based polyimides were prepared from the thermal imidization reaction of 6FDA with diamines of BAPAF, DAP, and DABA having a polar group of hydroxyL or carboxyl. Properties of the dense polyimide membranes were characterized and their gas permeation properties for H$_2$, $CO_2$, $O_2$, $N_2$, and CH$_4$ were investigated. Permeabilities, diffusion coefficients and diffusivity selectivities of polar group-containing polyimide membranes including 6FDA-BAPAF, 6FDA-DAP, and 6FDA-DABA polymer for the gases did not change largely. The separation properties of 6FDA-TrMPD polyimide membrane used as a reference polymer were compared with those of the polyimide membranes mentioned above. It was found that the polyimides of 6FDA-BAPAF, 6FDA-DAP, and 6FDA-DABA, which were soluble in alcohol or/and 2-methoxyethanol, could be applicable to the preparation of a dense composite membrane by dip-coating method.

• Animal Bioscience
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• 제35권9호
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• pp.1454-1460
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• 2022

Objective: Early environmental enrichment in life can improve cognition in animals. The effect of prenatal auditory stimulation on learning ability and fear level in chick embryos remained unexplored. Therefore, this study investigated the effect of prenatal auditory stimulation on the learning ability and fear level of chicks. Methods: A total of 450 fertilized eggs were randomly divided into 5 groups, including control group (C), low-sound intensity music group (LM), low-sound intensity noise group (LN), high-sound intensity noise group (HN) and high-sound intensity music group (HM). From the 10th day of embryonic development until hatching, group LM and group LN received 65 to 75 dB of music and noise stimulation. Group HN and group HM received 85 to 95 dB of noise and music stimulation, and group C received no additional sound. At the end of incubation, the one-trial passive avoidance learning (PAL) task and tonic immobility (TI) tests were carried out, and the serum corticosterone (CORT) and serotonin (5-HT) concentrations were determined. Results: The results showed that compared with the group C, 65 to 75 dB of music and noise stimulation did not affect the PAL avoidance rate (p>0.05), duration of TI (p>0.05) and the concentration of CORT (p>0.05) and 5-HT (p>0.05) in chicks. However, 85 to 95 dB of music and noise stimulation could reduce duration of TI (p<0.05) and the concentration of CORT (p<0.05), but no significant effect was observed on the concentration of 5-HT (p>0.05) and PAL avoidance rate (p>0.05). Conclusion: Therefore, the prenatal auditory stimulation of 85 to 95 dB can effectively reduce the fear level of chicks while it does not affect the learning ability.

• 대한정형도수물리치료학회지
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• 제21권2호
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• pp.15-24
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• 2015

Background: Many people are suffering from neck and shoulder pain due to muscle weakness, muscle fatigue, lack of exercise and accidents during exercise. In this study we compared the effects of McKenzie method and Mulligan technique method. Method: we randomly selected men(10) and women(10) and they are the 20s students of Busan material K college. We divided for McKenzie exercise group and Mulligan exercise group. McKenzie exercise and mulligan exercise applied cervical area three times a week for three weeks. We compared with pre-experiment and after 1~3 week through measuring the electromyography (EMG) change and neck range of motion (ROM). Results: The changes in the EMG at each exercise group, there was a statistically significant difference in each week. Although there was a significant difference after 1 week between the exercise group, the changes in the neck ROM at each exercise group there was no statistically significant difference. Conclusion: After experiment, EMG and neck ROM were increased in McKenzie exercise group and Mulligan exercise group. But Mulligan exercise group showed the change better than McKenzie exercise group in early stage. We suggest the Mulligan exercise method for recovering in early stage of neck ROM.

• 대한치과기공학회지
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• 제34권2호
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• pp.165-177
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• 2012

Purpose: The purpose of this study is to lay the groundwork for the development of appropriate training courses for a rapidly changing digital technology in the field of Dental technology. Methods: The subjects of this study were dental technicians, dental technology students, a professor of dental technology in Daegu and Gyeongbuk area and a self-administered structured questionnaire survey was conducted for 350 randomly selected people. Collected data were analyzed using SPSS Win 17.0 statistics program and analysis techniques include the frequency, percentage and cross-analysis. Results: The results of the survey are as follows. The usefulness of Major subjects was Full Denture laboratory (4.72 points), Dental Morphology (4.71 points), Crown and Bridge laboratory (4.69 points) in the instructor's group. The usefulness of Major subjects was Dental Morphology (4.56 points), Full Denture (4.36 points), Crown and Bridge laboratory (4.69 points) in the student's group. The usefulness of Major subjects was Dental Morphology (4.58 points), Dental Morphology laboratory (4.34 points), Partial Denture laboratory (4.30 points) in the dental technician's group. Subject with the highest usefulness of required course to open was CAD/CAM lecture and laboratory, the highest proportion of 91.2% and Implant laboratory was very useful (91.2%) in the instructor's group. Subject with the highest usefulness of required course to open was CAD/CAM lacture and laboratory, the highest proportion of 90.0% and Implant laboratory was very useful (91.2%) in the student's group. Subject with the highest usefulness of required course to open was CAD/CAM lacture and laboratory, the highest proportion of 91.2% and Implant laboratory was very useful (90.2%) in the dental technician's group. Conclusion: Semester of the subjects was required establishment of CAD/CAM lecture and laboratory in the third year first semester (85.1%) and Implant laboratory in the third year second semester the third year was the highest proportion of 94.1% in the instructor's group. 87.0% of students need to open CAD/CAM lacture and laboratory in the third year first semester, Implant laboratory in the third year second semester the third year was the highest proportion of 85.0% in the student's group. Semester of the subjects was required establishment of CAD/CAM lecture and laboratory in the third year first semester (81.0%) and Implant laboratory in the third year second semester the third year was the highest proportion of 80.0% in the dental technician's group.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권4호
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• pp.246-252
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• 2002

Two kinds of PZT cantilevers integrated with a piezoresistor have been newly designed, fabricated, and characterized for high speed AFM. In first cantilever, a piezoresistor is used to sense atomic force acting on tip, while in second cantilever, a piezoresistor is integrated to calibrate hysteresis and creep phenomena of the PZT cantilever. The fabricated PZT cantilevers provide high tip displacement of $0.55\mu\textrm{m}/V$ and high resonant frequency of 73 KHz. A new cantilever structure has been designed to prevent electrical coupling between sensor and PZT actuator and the proposed cantilever shows 5 times lower coupling voltage than that of the previous cantilever. The fabricated PZT cantilever shows a crisp scanned image at 1mm/sec, while the conventional piezo-tube scanner shows blurred image even at $180\mu\textrm{m}/sec$. The non-linear properties of the PZT actuator are also well calibrated using the piezoresistive sensor for calibration.

• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.215-221
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• 2017

The electroless plating process largely consists of substrate cleaning, seed formation (activator formation), and electroless plating. The most widely used activator in the seed formation step is Pd, and Sn ions are used to facilitate the formation of this Pd seed layer. This is problematic because the Sn ions interfere with the reduction of Cu ions during electroless plating; thus, the Sn ions must be removed by a hydrochloric acid cleaning process. This method is also expensive due to the use of Pd. In this study, Cu electroless plating was performed by forming a seed layer using a silver nanosol instead of Pd and Sn. The effects of the Ag nanosol concentration in the pretreatment solution and the pretreatment time on the thickness and surface morphology of the Cu layer were investigated. The degrees of adhesion to the substrate were similar for the electroless-plated Cu layers formed by conventional Pd activation and those formed by the Ag nanosol.

• 한국기계가공학회지
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• 제16권4호
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• pp.9-15
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• 2017

In hot forming process, the dies in which excessive worn or crack occurs is reused after repair. Generally hot forming dies are recycled through a welding repair method. Welding repair methods are highly dependent on the skills of engineer. It causes process defects such as dimensional defects and structural defects. Recently, the metal 3D printing method has been applied to the repair of used dies. The aim of this study is to evaluate the wear characteristics of AISI H13 tool steel repaired by 3D printing method. Three kinds of wear specimens were fabricated by using 3D printing, welding, and initial material. A pin-on-disk wear test was carried out to evaluate the wear characteristics. From the result of wear test, the wear characteristics of 3D printing method was superior to that of the welded material, and was similar to that of the initial material.

• 한국분말재료학회지
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• 제23권6호
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• pp.409-413
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• 2016

Electrical wire explosion in liquid media is a promising method for producing metallic nanopowders. It is possible to obtain high-purity metallic nanoparticles and uniform-sized nanopowder with excellent dispersion stability using this electrical wire explosion method. In this study, Ni-Fe alloy nanopowders with core-shell structures are fabricated via the electrical explosion of Ni-Fe alloy wires 0.1 mm in diameter and 20 mm in length in de-ionized water. The size and shape of the powders are investigated by field-emission scanning electron microscopy, transmission electron microscopy, and laser particle size analysis. Phase analysis and grain size determination are conducted by X-ray diffraction. The result indicate that a core-shell structured Ni-Fe nanopowder is synthesized with an average particle size of approximately 28 nm, and nanosized Ni core particles are encapsulated by an Fe nanolayer.

• 산학경영연구
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• 제11권
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• pp.67-81
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• 1998

본 연구는 대학에서 학생관련 민원 서비스의 개선을 위한 방안의 하나로 제조업에서 사용되어 온 그룹 테크놀로지 개념을 학생 민원 서비스업무를 대상으로 그 적용 가능성을 관계 문헌을 토대로 모색하였다. 또한 기존의 학생 민원 서비스의 업무 흐름과 경유 부서의 복잡성을 분석하여 새로운 서비스셀을 구축하기 위한 업무 절차와 규정을 개발하였다. 새로운 서비스셀에 대한 평가를 위하여 민원 서비스의 리엔지니어링 전후의 업무처리 시간을 측정하여 비교한 결과, 신설 부서의 추가 없이 새로운 서비스셀로 서비스 소요시간과 경유인원의 획기적인 개선을 도모하였다.