• Title/Summary/Keyword: AM feature

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Evaluation of Microstructure and Mechanical Properties in 17-4PH Stainless Steels Fabricated by PBF and DED Processes (PBF와 DED 공정으로 제조된 17-4PH 스테인리스 강의 미세조직 및 기계적 특성 평가)

  • Yoon, Jong-Cheon;Lee, Min-Gyu;Choi, Chang-Young;Kim, Dong-Hyuk;Jeong, Myeong-Sik;Choi, Yong-Jin;Kim, Da-Hye
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.2
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    • pp.83-88
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    • 2018
  • Additive manufacturing (AM) technologies have attracted wide attention as key technologies for the next industrial revolution. Among AM technologies using various materials, powder bed fusion (PBF) processes and direct energy deposition (DED) are representative of the metal 3-D printing process. Both of these processes have a common feature that the laser is used as a heat source to fabricate the 3-D shape through melting of the metal powder and solidification. However, the material properties of the deposited metals differ when produced by different process conditions and methods. 17-4 precipitation-hardening stainless steel (17-4PH SS) is widely used in the field of aircraft, chemical, and nuclear industries because of its good mechanical properties and excellent corrosion resistance. In this study, we investigated the differences in microstructure and mechanical properties of deposited 17-4PH SS by PBF and DED processes, including the heat treatment effect.

Analysis of Block Geometry of UltraCamX (UltraCamX 카메라의 블록기하 분석)

  • Lee, Seung Bok;Lee, Jae One;Cha, Sung Yeoul;Yun, Bu Yeol
    • Journal of Korean Society for Geospatial Information Science
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    • v.21 no.2
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    • pp.45-51
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    • 2013
  • Today, people who live in sea of information are strongly appearing desire about quicker and more accurate information. For a long time people wanted to know information about place that I am and where I must go out, and there are various methods to have a keen desire for position information. Equipment that is using most among the method is digital camera. In this study, the accuracy of external orientation, GCP and check point depending on array of GCP and regional feature are analyzed after AT(aerial triangulation) with UltraCamX in three selected study area with specific feature. As analysis result, we could get to know that area with a mountainous district rapidly decreased accuracy of external orientation according as number of GCP decreases, and area with high buildings became low in vertical accuracy of checkpoint. This study has performed the analysis of regional factors in aerial triangulation accuracy.

Frequency Characteristics of the Synchronous-Frame Based D-Q Methods for Active Power Filters

  • Wang, Xiaoyu;Liu, Jinjun;Hu, Jinku;Meng, Yuji;Yuan, Chang
    • Journal of Power Electronics
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    • v.8 no.1
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    • pp.91-100
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    • 2008
  • The d-q harmonic detecting algorithms are dominant methods to generate current references for active power filters (APF). They are often implemented in the synchronous frame and time domain. This paper researches the frequency characteristics of d-q synchronous transformations, which are closely related to the analysis and design issues of control system. Intuitively, the synchronous transformation is explained with amplitude modulation (AM) in this paper. Then, the synchronous filter is proven to be a time-invariant and linear system, and its transfer function matrix is derived in the stationary frames. These frequency-domain models imply that the synchronous transformation has an equivalent effect of frequency transformation. It is because of this feature, the d-q method achieves band-pass characteristics with the low pass filters in the synchronous frame at run time. To simplify these analytical models, an instantaneous positive-negative sequence frame is proposed as expansion of traditional symmetrical components theory. Furthermore, the synchronous filter is compared with the traditional bind-pass filters based on these frequency-domain analytical models. The d-q harmonic detection methods are also improved to eliminate the inherent coupling effect of synchronous transformation. Typical examples are given to verify previous analysis and comparison. Simulation and experimental results are also provided for verification.

QSEN Competencies in Pre-licensure Nursing Education and the Application to Cinenurducation (간호학생의 질 향상과 안전교육(QSEN) 역량개발을 위한 영화간호교육의 적용)

  • Oh, Jina;Shin, Hyewon;De Gagne, Jennie C.
    • The Journal of Korean Academic Society of Nursing Education
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    • v.18 no.3
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    • pp.474-485
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    • 2012
  • Purpose: The Quality and Safety Education for Nurses [QSEN] initiative group has identified six competencies (patient-centered care, teamwork and collaboration, evidence-based practice, quality improvement, safety, and informatics) for pre-licensure nursing education along with related knowledge, skills, and attitudes for each competency. The purpose of this article is to illustrate a teaching strategy that uses films to demonstrate the QSEN competencies in undergraduate nursing students. Method: A literature review was conducted to define QSEN competencies, and six feature-length commercial movies were selected through a systematic process. We provided film titles and their synopses that can be useful in teaching the QSEN six competencies to undergraduate nursing students. Results: Patch Adams for patient-centered care, Wit for teamwork and collaboration, Lorenzo's Oil for evidence-based practice, Am$\acute{e}$lie for quality improvement, Blindness and The Island for informatics can be applied in nursing classroom practices. Conclusion: Establishing the connection between QSEN competencies and cinenurducation is novel, yet it would provide a unique opportunity for nurse educators seeking to overcome the challenge of better preparing future nurses. In future studies, additional films should be considered to enhance nursing educational strategies.

Technical Investigation into the In-situ Electron Backscatter Diffraction Analysis for the Recrystallization Study on Extra Low Carbon Steels

  • Kim, Ju-Heon;Kim, Dong-Ik;Kim, Jong Seok;Choi, Shi-Hoon;Yi, Kyung-Woo;Oh, Kyu Hwan
    • Applied Microscopy
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    • v.43 no.2
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    • pp.88-97
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    • 2013
  • Technical investigation to figure out the problems arising during in-situ heating electron backscatter diffraction (EBSD) analysis inside scanning electron microscopy (SEM) was carried out. EBSD patterns were successfully acquired up to $830^{\circ}C$ without degradation of EBSD pattern quality in steels. Several technical problems such as image drift and surface microstructure pinning were taking place during in-situ experiments. Image drift problem was successfully prevented in constant current supplying mode. It was revealed that the surface pinning problem was resulted from the $TiO_2$ oxide particle formation during heating inside SEM chamber. Surface pinning phenomenon was fairly reduced by additional platinum and carbon multi-layer coating before in-situ heating experiment, furthermore was perfectly prevented by improvement of vacuum level of SEM chamber via leakage control. Plane view in-situ observation provides better understanding on the overall feature of recrystallization phenomena and cross sectional in-situ observation provides clearer understanding on the recrystallization mechanism.

Application of Three-Dimensional Light Microscopy for Thick Specimen Studies

  • Rhyu, Yeon Seung;Lee, Se Jeong;Kim, Dong Heui;Uhm, Chang-Sub
    • Applied Microscopy
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    • v.46 no.2
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    • pp.93-99
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    • 2016
  • The thickness of specimen is an important factor in microscopic researches. Thicker specimen contains more information, but it is difficult to obtain well focused image with precise details due to optical limit of conventional microscope. Recently, a microscope unit that combines improved illumination system, which allows real time three-dimensional (3D) image and automatic z-stack merging software. In this research, we evaluated the usefulness of this unit in observing thick samples; Golgi stained nervous tissue and ground prepared bone, tooth, and non-transparent small sample; zebra fish teeth. Well focused image in thick samples was obtained by processing z-stack images with Panfocal software. A clear feature of neuronal dendrite branching pattern could be taken. 3D features were clearly observed by oblique illumination. Furthermore, 3D array and shape of zebra fish teeth was clearly distinguished. A novel combination of two channel oblique illumination and z-stack imaging process increased depth of field and optimized contrast, which has a potential to be further applied in the field of neuroscience, hard tissue biology, and analysis of small organic structures such as ear ossicles and zebra fish teeth.

Reaction of Potassium 9-sec-Amyl-9-boratabicylco[3.3.1]nonane with Selected Organic Compounds Containing Representative Functional Groups

  • Cha Jin Soon;Yoon Mal Sook;Lee Kwang Woo;Lee Jae Cheol
    • Bulletin of the Korean Chemical Society
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    • v.10 no.1
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    • pp.75-80
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    • 1989
  • The approximate rates and stoichiometry of the reaction of excess potassium 9-sec-amyl-9-boratabicylco[3.3.1]nonane (K 9-sec-Am-9-BBNH) with selected organic compounds containing representative functional goups under standardized conditions (tetrahydrofuran, $0^{\circ}C)$ were examined in order to explore the reducing characteristics of the reagent for selective reductions. The reagent readily reduces aldehydes, ketones, acid chlorides and epoxides to the corresponding alcohols. However, carboxylic acid, aliphatic nitriles, t-amides, and some sulfur compounds show very little reactivity or no reactivity to this reagent. The most interesting feature of the reagent is that aromatic nitriles are reduced moderately to the corresponding aldehyde stage, wheras aliphatic nitriles are inert. In addition, the reagent shows a high stereoselectivity toward cyclic ketones at $0^{\circ}C$ and - $25^{\circ}C.$ The selectivity exhibited at $0^{\circ}C$ is comparable to that by lithium trisiamylborohydride at that temperature.

The Test of Mechanism Operation for 3D Printer Using Polygon Mirror (폴리곤 미러를 이용한 3D 프린터 기구부 동작 테스트)

  • Kwon, Dong-hyun;Heo, Sung-uk;Lim, Ji-yong;Oh, Am-suk;Kim, Wan-sik
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.10a
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    • pp.735-737
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    • 2016
  • In this paper, we conducted a test of the 3D printer injection method and LSU (Laser Scanning Unit) feature a fusion of the polygon mirror scanning system that is the core mechanism operation for 3D printers for office laser printers SLA system. These tests ensure that the laser was operating and control well was confirmed that a certain point is output to the X-axis by means of a laser module and a polygon mirror. And confirmed after the F-theta lens is incident on the fixed laser power of the beam, and correction according to the correction beam on the mirror reflection was confirmed jineunji the focus according to the Z-axis upper plate.

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A Study on the Implementing Strategies and components of Space for the Placeness Formation - Focus on Public Space Case - (장소성 형성의 공간구현 전략과 실행요소 연구 - 공공 공간 사례를 중심으로 -)

  • Kim, Mi-Young;Moon, Jeong-Min
    • Korean Institute of Interior Design Journal
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    • v.22 no.6
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    • pp.190-198
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    • 2013
  • With globalization and the execution of a self-governing system, the government-oriented system has been transformed into a city-oriented system. The importance of the competitive power of a city is thus increasing. Because of this each region is trying to develop its own differentiated image and to create branding using unique historical and cultural resources and, as one of the strategies for this, public spaces have been developed. For a public space to be used as a means to promote the attractiveness of a city, creates a local image and works as a medium to help a community of people realize a pleasant life. Therefore, in this study, I am clarified theoretically the meaning of placeness and form factors. and study realization methods in the space around the public space case. The results of the study are as following. In the modern space, Place is to be understood as a recognition and experience. Therefore rather than spatial structure physical fixed, recognition through the human experience is an important feature of the place-making, it is necessary to access in spatial planning based on this point of view. The factors of the placeness formation are physical environment factors, activity elements of the human, the meaning factors. and these elements form the placeness through via interaction. Therefore, even space implementation of the place, it is necessary to grasp the elements of each, as well as the physical aspects in particular, planning programmatic and various functions must be parallel strategically. There is a need to implement a space device that can be carried out in space activities.

Correlation of Jacques Lacan's Mirror Stage and the process of Remediation on Image Media (쟈크 라캉의 거울단계와 영상미디어의 매개과정과의 연관성)

  • Ahn, Sang-Hyuk
    • Archives of design research
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    • v.18 no.4 s.62
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    • pp.147-154
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    • 2005
  • In this paper, I am going to analyze a correlation of Jacques Lacan's Mirror Stage and the process of remediation on image media. It is because the remediation process of various digital media is letting people pass through one time of mirror stage again. Remediation for the Internet of traditional media, conflict with the virtual world and real world, identification that a virtual image changes a practical image is for it to be caused a remediation process by mutual link of various image media. The Narcissism which occurs in the relation a self with a idealized self searches a new own expression and forms a skillful mania culture. Reflexivity of active mania culture same as a Jacques Lacan's Mirror Stage is to be the possibility becoming the feature of media culture of today. However, if digital media culture generation spends extremely wasting time from the image media, these image media generations cannot grow into new future-type man. According to this, it is necessory to have a study on Visual Literacy that it is related to a Jacques Lacan's Mirror Stage.

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