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웹@매니아 리뷰

  • Korea Database Promotion Center
    • Digital Contents
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    • no.12 s.79
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    • pp.67-69
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    • 1999
  • 웹@매니아는 국내외 인터넷 솔루션의 벤치마킹을 비롯해 솔루션별 리뷰, 디렉토리 서비스, 뉴스 등을 제공하는 인터넷 비즈니스 전문 사이트(www.webmania.co.kr)이다. 본 코너에서는 웹@매니아에서 제공하는 벤치마킹 자료를 게재함으로써 인터넷 제품 선택에 가이드를 제시하고자 한다. 이번호에는 Instant Messenger의 기본 원리 및 제품별 특징에 대해 살펴본다.

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PIV measurement of step cavity with driven flow (구동류를 갖는 계단 캐비티의 PIV계측)

  • 조대환;김진구;이영호
    • Journal of Ocean Engineering and Technology
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    • v.12 no.1
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    • pp.113-119
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    • 1998
  • An experimental study was carried out in a three-dimensional cubic cavity driven by 2-dimensional plane Poiseuille flow for three kinds of Reynolds number, $10^4$, 3 $\times$ $10^4$ and 5 $\times$ $10^4$ based on the cavity width and cavity inlet mean flow velcoity. Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system. Laser based illumination and two-frame grey-level cross correlation algorithm are adopted. Severe unsteady flow fluctuation within the cavity are remarkable at above Re = 3 $\times$ $10^4$ Reynolds numbers and sheared mixing layer phenomena are also found at the region where inlet driving Poiseuille flow is collided with the clock-wise rotating main primary vortex at upper center area. Instant velocity profiles reveal that deformed forced vortex formation is observed throughout the separate two areas.

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A Study on circular Arc Approach for Motion Analysis of Oscillating Roller Follower and Disk Cam Mechanisms (요동운동 롤러 종동절과 디스크 캠 기구의 운동해석을 위한 원호 접근법에 관한 연구)

  • 구병국;신중호;윤호업;장옥화
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.523-526
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    • 2000
  • This paper performs the motion analysis for a disk cam and a follower mechanism using a circular arc method, a coordinate transformation method and an instant velocity method in order to find a contact point between the cam and the follower. Based on the proposed method, the displacement and the velocity are calculated by using the geometric relationships of the cam mechanism. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

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A Study on the Motion Analysis for Disk Cam Mechanism Using Circular Arc (원호접근법을 이용한 디스크 캠기구의 운동해석에 관한 연구)

  • Koo, B.K.;Shin, J.H.;Yoon, H.E.;Zhang, Y.H.
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.772-777
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    • 2000
  • Cam mechanisms are used commonly in many automatic machinery. Disk cam mechanisms has 4 different types according to the different types of followers. The motion characteristics of the cam mechanisms depend on the shape of the cam and the type of the follower. This paper performs the motion analysis for a disk cam and follower mechanism using a circular arc method and a coordinate transformation method in order to find a contact point of the cam and follower. The velocity is calculated by using the instant velocity concept. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

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A Study on Motion Analysis and Shape Design of Inverse Cam Mechanism with Square Shaped follower (사각형상 종동캠을 갖는 Inverse Cam Mechanism의 운동해석과 형상설계에 관한 연구)

  • Shin J.H.;Kwon S.M.;Kim J.C.;Kim B.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1299-1302
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    • 2005
  • Current mechanical devices are trending toward being a small size, high speedy, automation. For performing these functions, machinery elements organizing a machine should be designed exactly. Cams have high confidence and economics in ablility to transmit a motion. Accordingly, A cam mechanism is very important for processing the machine automatically. This paper introduce an inverse cam mechanism. A square shaped cam which cannot be commonly analyzed is designed and manufactured by using the NURBS interpolation algorithm. The objective of this paper is to develop a computer-aided design program. In this paper, a displacement curve of oscillating motion inverse cam mechanism with square shaped follower is analyzed. The data is redistibuted by the NURBS algorithm. A cam shape is designed by the instant velocity center method, and simulated to verify the validity of the operation state.

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A Study on the Kinetodynamic Analysis for General Disk Cam Driving Slider Mechanisms (캠구동 슬라이더기구의 기구동역학 해석에 관한 연구)

  • Shin, Joong-Ho;Kim, Jong-Soo;Ha, Kyong-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.6
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    • pp.871-883
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    • 1997
  • Kinetodynamics of a cam driving slider mechanism consists of kinematic analysis and force analysis. The kinematic analysis is to determine the kinematic characteristics of a cam driving mechanism and a slider mechanism. The force analysis is to determine the joint forces of links, the contact forces of the cam and follower, and the driving torque of a main shaft. This paper proposes a close loop method and a tangent substitution method to formulate the relationships of kinematic chains and to calculate the displacement, velocity and acceleration of the cam driving slider mechanism. Also, and instant velocity center method is proposed to determine the cam shape from the geometric relationships of the cam and the roller follower. For dynamic analysis, the contact force and the driving torque of the cam driving slider mechanism are calculated from the required sliding forces, sliding motion and weight of the slider.

Molybdenum release from high burnup spent nuclear fuel at alkaline and hyperalkaline pH

  • Sonia Garcia-Gomez;Javier Gimenez;Ignasi Casas;Jordi Llorca;Joan De Pablo;Albert Martinez-Torrents;Frederic Clarens;Jakub Kokinda;Luis Iglesias;Daniel Serrano-Purroy
    • Nuclear Engineering and Technology
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    • v.56 no.1
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    • pp.34-41
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    • 2024
  • This work presents experimental data and modelling of the release of Mo from high-burnup spent nuclear fuel (63 MWd/kgU) at two different pH values, 8.4 and 13.2 in air. The release of Mo from SF to the solution is around two orders of magnitude higher at pH = 13.2 than at pH = 8.4. The high Mo release at high pH would indicate that Mo would not be congruently released with uranium and would have an important contribution to the Instant Release Fraction, with a value of 5.3%. Parallel experiments with pure non irradiated Mo(s) and XPS determinations indicated that the faster dissolution at pH = 13.2 could be the consequence of the higher releases from metallic Mo in the fuel through a surface complexation mechanism promoted by the OH- and the oxidation of the metal to Mo(VI) via the formation of intermediate Mo(IV) and Mo(V) species.

Quality stability of anchovy-based powder for instant soup packed in tea bag (탈산소제에 의한 Tea bag 포장한 멸치 복합 분말의 저장 안정성)

  • Lee, Ho-Yeon;Chung, Bu-Gil;Son, Kwang-Tae;Joo, Dong-Sik;Kim, Jin-Soo;Lee, Eung-Ho
    • Applied Biological Chemistry
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    • v.36 no.5
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    • pp.321-325
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    • 1993
  • The anchovy-based powder for instant soup packed in twenty tea bag were repacked with (Product B) or without oxygen absorber (Product A) in laminated film bag $(PVDC/OPP,\;thickness:\;100.5\;{\mu}m,\;size:22{\times}18cm)$, and then stored at ambient temperature $(25{\pm}3^{\circ}C)$. Moisture, crude protein and crude lipid contents in anchovy-based powder for instant soup were 12.1%, 54.7% and 2.9%, respectively. Moisture content showed little changes during storage in both product (A) and (B). pH and saturated fatty acid such as 20 : 5 and 22 : 6 decreased, while volatile basic nitrogen content, carbonyl value, thiobarbituric acid value, monoenoic fatty acid such as 16 : 0, brown pigment formation and Hunter values increased during storage of product (A). But, these values showed a little change during storage of product (B). It is concluded that anchovy-based powder for instant soup can be handily and safely used during storage of 150 days.

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