• Title/Summary/Keyword: Reverse-time

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Opportunities and Challenges for the Development of Chinese Intelligent Manufacturing Science and Technology Enterprises with "Anti-Globalization"

  • JINMING ZHANG;ZIYANG LIU
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2023.01a
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    • pp.443-445
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    • 2023
  • Following the global financial crisis, the global value chain contracted, and characteristics of "reverse globalization" of the economy and trade gradually emerged. This is due to the term "reverse globalization" referring to a shift away from globalization. Within a short period of time, the phenomenon known as "reverse globalization" developed as an inescapable obstacle, coinciding with the development and dissemination of the COVID-19 virus. At some time in the distant future, the "reverse globalization" of economic trade and the "globalization" of the digital economy will co-dominate the shifting trend of the global economic landscape. This will happen gradually over time. The goal of this research is to look at the minor changes that happened in the methods and techniques used by the economic mechanism known as "globalization against the flow." It employs Chinese smart manufacturing companies as a model and proposes a digital drive model to investigate the prospects and constraints of smart manufacturing technology enterprise innovation development under "reverse globalization," with the goal of establishing a digital innovation development path. The theoretical insights given in this study have the potential to serve as a reference for China as it attempts to build a new growth pattern based on a double-cycle and promote a new type of globalization.

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Improvement of Reverse-time Migration using Modified Receiver Aperture (수진기 배열 변경에 의한 역시간 구조보정 영상 개선 연구)

  • Cheong Soon-Hong;Shin Chang-Soo
    • Geophysics and Geophysical Exploration
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    • v.6 no.3
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    • pp.153-159
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    • 2003
  • Using reciprocity theorem, one direction aperture of seismogram can be extended to full aperture seismogram. Modified seismogram is applied to reverse time migration only to acquire improved migration image. In this paper, we tested reverse time migration with the Marmousi velocity data to examine efficiency of modified seismogram. And linearly increasing velocity model is selected and examined for a case where velocity data is insufficient. When true velocity is applied, using modified seismogram enhances the reverse time migration image more than using original seismogram. In the case of using linearly increasing velocity model, migration image is distorted. So low frequency source is brought in migration process. Reverse time migration image with low frequency source and linearly increasing velocity model is improved when modified seismogram is used. From the result of study, seismogram modification by reciprocity theorem is useful and migration image can be enhanced.

Mechanical and Elastic Wave Properties of STS316L with Different Reverse Transformation Temperature and Time (역변태 온도 및 시간이 다른 STS316L의 기계적 및 탄성파 특성)

  • Do, Jae-Yoon;Tak, Young-Joon;Shin, Ki-Hang;Nam, Ki-Woo
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.6_2
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    • pp.1055-1062
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    • 2022
  • In this study, the mechanical properties of 80% cold-rolled austenitic 316L stainless steel were evaluated using specimens subjected to reverse transformation at 500-750℃ for 20 minutes and reverse transformation at 700℃ for 2-60 minutes. Also, for the elastic wave obtained from the tensile test, the dominant frequency according to the reverse transformation condition was investigated by time-frequency analysis. The SEM image of the 80% cold-rolled material was transformed into martensite and showed line and cross shapes. The TEM image showed that line shapes were shown at the grain, and grain boundary of martensite. The higher the heat treatment temperature and the longer time, the larger the grain. Tensile strength decreased as the heat treatment temperature and time increased, but elongation increased. Hardness was proportional to tensile strength. This is because the grain with different directions showed the same direction due to reverse transformation. The dominant frequency was decreased and then increased as the temperature and time increased. This is because the direction of the grain is different at a low temperature and the same direction is shown at a high temperature.

Rapid Prototyping from Reverse Engineered Geometric Data (리버스 엔지니어링으로 생성된 데이터를 이용한 쾌속 조형 기술 연구)

  • Woo, Hyuck-Je;Lee, Kwan-Heng
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.1 s.94
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    • pp.95-107
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    • 1999
  • The design models of a new product in general are created using clay models or wooden mock-ups. The reverse engineering(RE) technology enables us to quickly create the CAD model of the new product by capturing the surface of the model using laser digitizers or coordinate measuring machines. Rapid prototyping (RP) is another technology that can reduce the product development time by fabricating the physical prototype of a part using a layered manufacturing technique. In reverse engineering process, however, the digitizer generates an enormous amount of point data, and it is time consuming and also inefficient to create surfaces out of these data. In addition, the surfacing operation takes a great deal of time and skill and becomes a bottleneck. In rapid prototyping, a faceted model called STL file has been the industry standard for providing the CAD input to RP machines. It approximates the CAD model of a part using many planar triangular patches and has drawbacks. A novel procedure that overcomes these problems and integrates RE with RP is proposed. Algorithms that drastically reduce the point clouds data have been developed. These methods will facilitate the use of reverse engineered geometric data for rapid prototyping, and thereby will contribute in reducing the product development time.

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Searching of Information on Reverse left/right Space in Sports-Shop and Features of Its Visual Appreciation - Through Comparison of Original and Reverse left/right Image Space - (스포츠 매장의 전회에 따른 정보 탐색과 시각적 이해 특성 - 원-공간과 전회-공간의 이미지 비교를 통해 -)

  • Kim, Jong-Ha
    • Korean Institute of Interior Design Journal
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    • v.25 no.5
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    • pp.71-81
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    • 2016
  • This research has been carried out with the objects of sporting goods shops to find out what structure of those shops raises more interest from customers. The tracking eyes on the objects which are the same but seen to have different structures has revealed the followings. Customers' visual appreciation of Reverse left/right Images (11.1) was found to be higher than that of Original Images (10.6). Furthermore, the reverse left/right image of the space also was found to attract more interest from customers, which led them to have longer observation. The below is about the interpretation of the spatial exploration by observation time and the appreciation of its visual content in line with the experiment objects of selling spaces. The longer the space was observed, (1)the higher the expansive searching of space was, (2)the more spots were observed as if they did not know what to see after they first observed at early hours, (3)later (in the time range of 64~73 seconds) they came to look at the spots in which they got interested, (4)and then again they suddenly got lost what to see. When the change of observation characteristics by time range is reviewed, it can be seen that the searching of original images is changed from Divergent Feature to Convergent Feature when the observation time increases from the early stage of observation to the later. On the contrary, the reverse left/right images were found to have the opposite searching features, that is, from convergent exploration to divergent exploration. These findings show that the reverse left/right images of the sporting goods shops, which were the experiment objects, have more factors attracting customers' attention and interest and that it is the very shop-structure which makes customers have better visual appreciation of those shops.

50V Power MOSFET with Improved Reverse Recovery Characteristics Using an Integrated Schottky Body Diode (Schottky Body Diode를 집적하여 향상된 Reverse Recovery 특성을 가지는 50V Power MOSFET)

  • Lee, Byung-Hwa;Cho, Doo-Hyung;Kim, Kwang-Soo
    • Journal of IKEEE
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    • v.19 no.1
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    • pp.94-100
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    • 2015
  • In this paper, 50V power U-MOSFET which replace the body(PN) diode with Schottky is proposed. As already known, Schottky diode has the advantage of reduced reverse recovery loss than PN diode. Thus, the power MOSFET with integrated Schottky integrated can minimize the reverse recovery loss. The proposed Schottky body diode U-MOSFET(SU-MOS) shows reduction of reverse recovery loss with the same transfer, output characteristic and breakdown voltage. As a result, 21.09% reduction in peak reverse current, 7.68% reduction in reverse recovery time and 35% improvement in figure of merit(FOM) are observed when the Schottky width is $0.2{\mu}m$ and the Schottky barrier height is 0.8eV compared to conventional U-MOSFET(CU-MOS). The device characteristics are analyzed through the Synopsys Sentaurus TCAD tool.

A Study on the Selection of Highly Flexible Blanket for Reverse Offset Printing (Reverse Offset Printing용 고신축성 Blanket 재료 선정에 관한 연구)

  • Shin, Seunghang;Kim, Seok;Cho, Young Tae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.5
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    • pp.121-127
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    • 2021
  • Reverse offset printing is considering as an emerging technology for printed electronics owing to its environmentally friendliness and cost-effectiveness. In reverse offset printing, selecting the materials for cliché and blanket is critical because of its minimum resolution, registration errors, aspect ratio of reliefs, pattern area, and reusability. Various materials such as silicon, quartz, glass, electroplated nickel plates, and imprinted polymers on rigid substrates can be used for the reverse offset printing of cliché. However, when new structures are designed for specific applications, new clichés need to re-fabricated each time employing multiple time-consuming and costly processes. Therefore, by modifying the blanket materials containing the printing ink, several new structures can be easily created using the same cliché. In this study, we investigated various elastomeric materials and evaluated their applicability for designing a highly stretchable blanket with controlled elastic deformation to implement tunable reverse offset printing.

Effects of Electrostatic Discharge Stress on Current-Voltage and Reverse Recovery Time of Fast Power Diode

  • Bouangeune, Daoheung;Choi, Sang-Sik;Cho, Deok-Ho;Shim, Kyu-Hwan;Chang, Sung-Yong;Leem, See-Jong;Choi, Chel-Jong
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.4
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    • pp.495-502
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    • 2014
  • Fast recovery diodes (FRDs) were developed using the $p^{{+}{+}}/n^-/n^{{+}{+}}$ epitaxial layers grown by low temperature epitaxy technology. We investigated the effect of electrostatic discharge (ESD) stresses on their electrical and switching properties using current-voltage (I-V) and reverse recovery time analyses. The FRDs presented a high breakdown voltage, >450 V, and a low reverse leakage current, < $10^{-9}$ A. From the temperature dependence of thermal activation energy, the reverse leakage current was dominated by thermal generation-recombination and diffusion, respectively, at low and high temperature regions. By virtue of the abrupt junction and the Pt drive-in for the controlling of carrier lifetime, the soft reverse recovery behavior could be obtained along with a well-controlled reverse recovery time of 21.12 ns. The FRDs exhibited excellent ESD robustness with negligible degradations in the I-V and the reverse recovery characteristics up to ${\pm}5.5$ kV of HBM and ${\pm}3.5$ kV of IEC61000-4-2 shocks. Likewise, transmission line pulse (TLP) analysis reveals that the FRDs can handle the maximum peak pulse current, $I_{pp,max}$, up to 30 A in the forward mode and down to - 24 A in the reverse mode. The robust ESD property can improve the long term reliability of various power applications such as automobile and switching mode power supply.

Numerical analysis of local exhaust effectiveness using reverse-flow calculation method (역유동계산법을 이용한 국소배기효율의 수치해석)

  • 한화택
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.6
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    • pp.658-665
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    • 1998
  • This paper investigates local exhaust effectiveness in a room with a supply and an exhaust slots on the ceiling. The mean age of air is an indicator of supply effectiveness, while the mean residual life time can be used as an indicator of exhaust effectiveness. The distribution of local mean residual life time in a space is calculated by four different numerical procedures. The reverse-flow calculation method has been proved to show quite accurate results while it can save considerable amount of computation time and efforts, compared to the method by its original definition. It is concluded that the diffusion term in the equation of mean residual life time can be neglected. The spatial and temporal diffusion characteristics of the contaminant are also discussed.

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Analysis of Switching Noise Time Characteristic and Estimation of Frequency Spectrum (스위칭 잡음의 시간 특성 분석을 통한 주파수 특성 예측)

  • Choi, Han-Ol;Ryu, Seung-Real;Kim, Eun-Ha;Park, Dong-Chul;Lee, Jae-Hyun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.5
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    • pp.640-645
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    • 2012
  • DC-DC converter and DC-AC inverter in a hybrid electric vehicle (HEV) generate the switching noise. It may be generated by the reverse recovery operation of the power diode in the switching circuit of the converter or the inverter. The shape of the reverse recovery region may be determined by both reverse time and recovery time in the diode. So, in this paper, the frequency spectrum of switching noise was estimated by the shape of the reverse recovery region and compared with the measured results. It shows that the meaningful region of the frequency spectrum is directly related with the reverse time.