• 한국레이저가공학회지
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• 제11권4호
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• pp.29-34
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• 2008

Ultraviolet laser micromachining has increasingly been applied to the electronics industry where precision machining of high-density, multi-layer, and multi material components is in a strong demand. Due to the ever-decreasing size of electronic products such as cellular phones, MP3 players, digital cameras, etc., flexible printed circuit board (FPCB), multi-layered with polymers and metals, tends to be thicker. In present, multi-layered FPCBs are being mechanically cut with a punching die. The mechanical cutting of FPCBs causes such defects as burr on layer edges, cracks in terminals, delamination and chipping of layers. In this study, the laser cutting mechanism of FPCB was examined to solve problems related to surface debris and short-circuiting that can be caused by the photo-thermal effect. The laser cutting of PI and FCCL, which are base materials of FPCB, was carried out using a pico-second laser(355nm, 532nm) and nano-second UV laser with adjusting variables such as the average/peak power, scanning speed, cycles, gas and materials. Points which special attention should be paid are that a fast scanning speed, low repetition rate and high peak power are required for precision machining.

• 한국문헌정보학회지
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• 제18권
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• pp.213-276
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• 1990

To revise and develop a 'Model' Curriculum for training the middle standing professionals equipped with professional technology and theories at the spot of the library, such process were executed as research on bibliographic material and literature, utilization of examination of various questionnaires, interviews with middle standing librarians at the spot of the library, a review on the operational state of the Professor's Association of Library Science of Junior Colleges, some consultation with the Research & Deliberation Committee on Curriculums, etc., and to review the present department of library science at the two-year course's short-term colleges or institutes in foreign countries, Germany which is thought to be similar to our nation's situations and its level of economy and Singapore which is considered to be a newly emerging nation were looked into typically. In particular, since studies on the curriculums of the Library Science Dept. of colleges had already preceded, thereby the framework of the 'Model' curriculum was already achieved, however to review how well such framework is applied to the spot of education and give some improvement on that, some unrelistic findings of different subjects in consideration with reality, while comparing those curriculum schedules of each Library Science Dept. with the 'Model' curriculum schedule, were supplemented or revised to be fit to reality. For some supplementing or revising proposals on the pre studied 'Model' curriculum, some tentative plans which focussed on each field respectively and some tentative plans which focussed on cultural subjects, required major subjects and elective subjects were suggested in duality to be referred to. On such a process of forming a harmony of educational theories and practice, it was planned to revise and develop curriculum in a sense emphasizing on practical exercise, and tried not to neglect on each of the fields of the curriculum centered on the areas of materials organization, linguistics, information resource, information science, library organization, & administration, etc. The study on curriculums should be performed flexible to be applied to the accelerating transition of sciences, and be good examples in instruction.

• Journal of Biosystems Engineering
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• 제43권3호
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• pp.185-193
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• 2018

Purpose: The purpose of this study was to analyze the performance factors of a rotary impact-type thresher to develop a sesame and perilla thresher, specifically to analyze the cut length of the stems and the threshing rates based on the relationship between the blade velocity and feeding speed. Methods: The materials were dried within a range of 12.3-13.0% to test the impact cut by bending. The cut lengths of the perilla and sesame stems were categorized in 6 ranges (~7.0, 7.1-10.0, 10.1-13.0, 13.1-16.0, 16.1-20.0, 20.1- (cm)). For testing the cut length and threshing rate, the upward-rotating blade velocity was varied as 11.0 m/s, 13.5 m/s, and 22.3 m/s. Feeding speeds were changed from 0.1 m/s to 2.2 m/s by the inverter connected to the feed motor. The feed rate and threshing rates without cover-casing were evaluated with the factors of thresher testing. Results: The mean cut length of the stem decreased as the blade velocity increased and/or the feeding speed decreased. As the feed rate increased up to 17.5 g/s, the cut length distributions showed no significant difference. The threshing rate was 98.9% for sesame, and flexible according to the blade velocity and feeding speed of the perilla. Conclusion: Feeding material too fast could produce longer cut stem segments, therefore, a feeding speed less than 2.2 m/s is recommended. A blade velocity of 13.5 m/s is preferable for both sesame and perilla with regard to cut length and threshing rate.

• 대한안전경영과학회지
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• 제6권3호
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• pp.211-235
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• 2004

Component based design is perceived as a key technology for developing advanced real-time systems in a both cost- and time effective manner. Already today, component based design is seen to increase software productivity, by reducing the amount of effort needed to update and maintain systems, by packaging solutions for re-use, and easing distribution. Nowdays, a thousand and one companies in If(Information Technology) industry such as Sl(System Integration) and software development companies, regardless of scale of their projects, has spent their time and endeavor on developing reusable business logic. The component software is the outcome of software developers effort on overcoming this problem; the component software is the way propositioned for quick and easy implementation of software. In addition, there has been lots of investment on researching and developing the software development methodology and leading If companies has released new standard technologies to help with component development. For instance, COM(Component Object Model) and DCOM(Distribute COM) technology of Microsoft and EJB(Enterprise Java Beans) technology of Sun Microsystems has turned up. Component-Based Development (CBD) has not redeemed its promises of reuse and flexibility. Reuse is inhibited due to problems such as component retrieval, architectural mismatch, and application specificness. Component-based systems are flexible in the sense that components can be replaced and fine-tuned, but only under the assumption that the software architecture remains stable during the system's lifetime. In this paper, It suggest that systems composed of components should be generated from functional and nonfunctional requirements rather than being composed out of existing or newly developed components. about implements and accomplishes the modeling for the Product Control component development by applying CCD(Contract-Collaboration Diagram), one of component development methodology, to MRP(Material Requirement Planning) System

• Corrosion Science and Technology
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• 제7권5호
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• pp.283-287
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• 2008

The drag reduction agency (DRA) for gas pipeline, a novel method used for reducing friction or drag on a gas flowing to increase the transmission efficiency of gas pipeline, is a more flexible and economical technology than internal flow efficient coatings. In this paper, an effective DRA has been developed in Authors' Institute by analyzing the hydrodynamic friction resistance on internal gas pipeline and then studying the work mechanism and molecular structure of DRA. In the meantime, a group of property test for selecting DRA material has been determined, including viscosity, contact angle, volatility, corrosion, slab extending, and flow behavior in horizontal tube. The inhibition efficiency and drag reduction efficiency of the developed DRA have been investigated finally based on the relevant test methods. Results of corrosion test show that the developed DRA has very good inhibition effect on mild steel by brushing a thin layer of DRA on steel specimens, giving inhibition efficiency of 91.2% and 73.1% in 3%NaCl solution and standard salt fog environment respectively. Results of drag-reducing test also show that the Colebrook formula could be used to calculate friction factors on internal pipes with DRA as the Reynolds number is in the range of $0.75\times10^5\sim2.0\times10^5$. By comparing with normal industrial pipes, the friction resistance coefficient of the steel pipe with DRA on internal wall decreases by 13% and the gas flux increases by 7.3% in testing condition with Reynolds number of $2.0\times10^5$.

• 복식문화연구
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• 제25권3호
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• pp.270-284
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• 2017

This study aimed to create 3D-printed insoles for flat-footed senior men using 3D systems. 3D systems are product-manufacturing systems that use 3-dimensional technologies like 3D scanning, 3D modeling, and 3D printing. This study used a 3D scanner (NexScan2), 3D CAD programs including Rapidform, AutoCAD, SolidWorks, Nauta+ compiling program, and a 3D printer. In order to create insoles for flat-footed senior men, we analyzed horizontal sections of 3D foot scans We selected 20 flat-footed and 20 normal-footed subjects. To make the 3D insole models, we sliced nine lines on the surface of the subjects' 3D foot scans, and plotted 144 points on the lines. We calculated the average of these 3D coordinates, then located this average within the 3D space of the AutoCAD program and created 3D sole models using the loft surface tools of the SolidWorks program. The sole models for flat feet differed from those of normal feet in the depth of the arch at the inner sideline and the big toe line. We placed the normal-footed sole model on a flat-footed sole model, and the combination of the two models resulted in the 3D insole for flat feet. We printed the 3D modeled insole using a 3D printer. The 3D printing material was an acrylic resin similar to rubber. This made the insole model flexible and wearable. This study utilized 3D systems to create 3D insoles for flat-footed seniors and this process can be applied to manufacture other items in the fashion industry as well.

• Nuclear Engineering and Technology
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• 제41권4호
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• pp.493-520
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• 2009

During the last four decades, 16 Pressurized Water Reactors (PWR) and 4 Pressurized Heavy Water Reactors (PHWR) have been constructed and operated in Korea, and nuclear fuel technology has been developed to a self-reliant state. At first, the PWR fuel design and manufacturing technology was acquired through international cooperation with a foreign partner. Then, the PWR fuel R&D by Korea Atomic Energy Research Institute (KAERI) has improved fuel technology to a self-reliant state in terms of fuel elements, which includes a new cladding material, a large-grained $UO_2$ pellet, a high performance spacer grid, a fuel rod performance code, and fuel assembly test facility. The MOX fuel performance analysis code was developed and validated using the in-reactor test data. MOX fuel test rods were fabricated and their irradiation test was completed by an international program. At the same time, the PWR fuel development by Korea Nuclear Fuel (KNF) has produced new fuel assemblies such as PLUS7 and ACE7. During this process, the design and test technology of fuel assemblies was developed to a self-reliant state. The PHWR fuel manufacturing technology was developed and manufacturing facility was set up by KAERI, independently from the foreign technology. Then, the advanced PHWR fuel, CANFLEX(CANDU Flexible Fuelling), was developed, and an irradiation test was completed in a PHWR. The development of the CANFLEX fuel included a new design of fuel rods and bundles.. The nuclear fuel technology in Korea has been steadily developed in many national R&D programs, and this advanced fuel technology is expected to contribute to a worldwide nuclear renaissance that can create solutions to global warming.

• 한국세라믹학회지
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• 제55권5호
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• pp.492-497
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• 2018

This paper reports the efficacy of tape casting using an Ag-10 wt% CuO filler for the successful joining of a sintered $Ce_{0.9}Gd_{0.1}O_{2-{\delta}}-La_{0.7}Sr_{0.3}MnO_{3{\pm}{\delta}}$ (GDC-LSM) ceramic with a SUS 460 FC metal alloy by reactive air brazing. The as-prepared green tape was highly flexible without drying cracks, and the handling was easy when used as a filler material for reactive air brazing. Heat treatment for the GDC-LSM/SUS 460 FC joint was performed at $1050^{\circ}C$ for 30 min in air. Microstructural observations indicated a reliable and compact joining. The room temperature mechanical shear strength of the as-brazed joints was $60{\pm}8MPa$ with a cohesive failure. The flexural strength of joints was measured from room temperature up to $850^{\circ}C$, where the strength retention revealed to be almost 100% at $500^{\circ}C$. However, the joints showed a degradation in strengths at 800 and $850^{\circ}C$, exhibiting strength retentions of 57% and 37%, respectively.

• 한국주거학회논문집
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• 제25권4호
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• pp.39-46
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• 2014

This research was for the investigation and analysis of the illustration of modular construction application which is different use by each school facility since modular construction related examples are rare in domestic situation, and it has a limitation because of its being basic research material for generating the basic form of modular construction. The research results are as followings. First, in case of school facility from illustration investigation results, module measurement of class modulation is as similar as $3m{\times}10m$, but in resident facility the planning of more flexible plane shape can be possible since modules of 6 cases are free and various, and facade form of various types can be appeared by combination of module unit. Second, as a result of the generated characteristics in compared analysis of representative examples, school facilities were highly indicated for movability and duration reduction areas, and the flexibility, economic efficiency, and environment-friendliness was indicated low relatively. Third, the basic planning types of modular construction can be largely divided into layered type, horizontal (straightway) type, and compound type. The layered type has a short traffic line and facility system and is appropriate for the low-rise form unless separate construction method is used since it is susceptible to load. The horizontal type is advantageous for securing an opening since it has wide extent in light but has a long traffic line and facility system. Finally, the compound type can be possible for planning of various forms but needs the combination of various unit modules and traffic line and facility plan for it can be difficult.

• 한국농촌건축학회논문집
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• 제18권4호
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• pp.1-8
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• 2016

This study is to investigate the meaning and value of Usonian Automatic House System(UAHS) of Frank Lloyd Wright in his later period, focused on materials, methods, and his thoughts. The results of this study are follows. UAHS was the outcome of moderate cost and prefab house which Wright had successively attempted after the early Prairie period. The construction was simple and comparatively cheap, but subsequent automatics were difficult and expensive to build. Nevertheless, it was sufficiently flexible to support a rather wide range of house designs. Concrete was the inert mass and a plastic material. Wright saw a kind of weaving coming out of it. He also saw a kind of concrete masonry, steel for warp and masonry units for woof in the automatic concrete block. The reinforced bars in hollowed joints of concrete block increased the safety factor and affected the expression of the construction through the stabilization they provided. But they did not give concrete block the capability of structural span. Standardization as the soul of the machine might be seen in UAHS. The concrete blocks were more cheap, lighter, and larger hollowed plain than textile blocks in 1920s. But the variety of pattern and different block types in the UAHS were achieved at some sacrifice of standardization. The repetitive nature of production was compromised for artistic goals. The sense of compromise was not maximized, however, because the units as installed looked far more repetitive than they actually were.