• Title/Summary/Keyword: Break-In

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A Study to Improve the Interface Strength of Composite Materials by the Radiation of Ultrasonic Energy (초음파 조사에 의한 복합재료의 계면특성의 보강 개선에 관한 연구 (II))

  • Lee, Sang-Kook;Jhqun, Choon-Saing;Kim, Ik-Nyon
    • Proceedings of the KIEE Conference
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    • 1988.11a
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    • pp.179-182
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    • 1988
  • This study is to investigate the adhesive strength of composite material's interface on the experimental methode of tree growth in the material. The results are as fellows 1) The irradiations of ultrasonic energy cause the mechanical vibration in the polymer composite materials of fluid state, so then bring about physical dispersion and heat form inorganic materials, being supposed to produce chemical crosslinking reaction, decreasing of voids between filler and matrix. 2) The characterics of the breakdown are increased by using coupling agent in the composite material. 3) As the intensity of ultrasonic energy and its irradiated time are larger, the tree inception and break-down voltages increase and the tree growing is slower. so we obtain that the interface adhesive force tan be strengthened by the irradiation of ultrasonic energy.

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A High Breakdown and Efficient GM-Estimator in Linear Models

  • Song, Moon-Sup;Park, Changsoon;Nam, Ho-Soo
    • Journal of the Korean Statistical Society
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    • v.25 no.4
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    • pp.471-487
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    • 1996
  • In this paper we propose an efficient scoring type one-step GM-estimator, which has a bounded influence function and a high break-down point. The main point of the estimator is in the weighting scheme of the GM-estimator. The weight function we used depends on both leverage points and residuals So we construct an estimator which does not downweight good leverage points Unider some regularity conditions, we compute the finite-sample breakdown point and prove asymptotic normality Some simulation results are also presented.

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DEVELOPMENT OF THE JOINING PROCESSES IN A GLOBAL PERSPECTIVE

  • Pekari, Bertil
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.1-14
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    • 2002
  • There is a continuous development of the most common welding processes like MMA, MIG/MAG, PAW and SAW. At the same time there is a conversion from stick electrodes to solid and cored wires with an increased productivity as a result. In parallel with these changes new processes are introduced and implemented. The number of Friction Stir Welding installations is starting to grow fast Hybrid laser welding has probably made a technical break through. The Magnetic Pulse Welding process is taking off. The different mechanical joining methods; clinching and self-piercing riveting; must not be forgotten. Structural adhesive is another method to consider.

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A Study on the Network QoS Management for Telemedicine Service based on Internet (인터넷 기반의 원격의료 서비스를 위한 네트워크 QoS 관리에 대한 연구)

  • 박정연
    • Journal of the Korea Society of Computer and Information
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    • v.7 no.4
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    • pp.24-32
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    • 2002
  • Recent advances in Telecommunication and Internet have how made it possible to break the space-time barriers and allow physicians to deliver health care to patients at any time and any place, having led to a new branch of computer applications called Telemedicine System. In Telemedcine, Network and I/O performance requirements are generally more important than computing capability. Accordingly, this thesis is aimed at inquiring into how to satisfy QoS guarantee of network to compensate for the defects of the existing best-effort services and suggesting how to solve network bottleneck problem. using DiffServ in Telemedicine service system through Internet.

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Dual Substituent Effects on Pyridinolysis of Bis(aryl) Chlorothiophosphates in Acetonitrile

  • Barai, Hasi Rani;Lee, Hai Whang
    • Bulletin of the Korean Chemical Society
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    • v.35 no.6
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    • pp.1754-1758
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    • 2014
  • The nucleophilic substitution reactions of bis(Y-aryl) chlorothiophosphates (1) with X-pyridines are investigated kinetically in acetonitrile at $35.0^{\circ}C$. The free energy relationships with both X and Y are biphasic concave upwards with a break point at X = 3-Ph and Y = H, respectively. The sign of cross-interaction constants (CICs; ${\rho}_{XY}$) is positive with all X and Y. Proposed mechanism is a stepwise process with a rate-limiting leaving group departure from the intermediate with all X and Y. The kinetic results of 1 are compared with those of Y-aryl phenyl chlorothiophosphates (2). In the case of Y = electron-withdrawing groups, the cross-interaction between Y and Y, due to additional substituent Y, is significant enough to change the sign of ${\rho}_{XY}$ from negative with 2 to positive with 1, indicative of the change of mechanism from a rate-limiting bond formation to bond breaking.

Dehydration and RDF Production of Organic Wastes with Pressurized Hydrothermal Treatment Process (증기가압형 처리공정을 이용한 유기성 폐기물의 건조처리 및 고형연료화)

  • Park, Se-Joon;Choi, Young-Chan;Choi, In-Kyu
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.5
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    • pp.439-446
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    • 2009
  • This paper investigates the dehydration and RDF (Refuse Derived Fuel) production of organic wastes, livestock manure and sewerage sludge with pressurized hydrothermal treatment process. The renewable technology for the organic wastes must involve short treatment time required, reusable energy source, anti-odor and viruses, low cost for the treatment, and well-fertilization. The pressurized hydrothermal treatment process promotes to evaporate moisture in the waste after being shortly treated in a reactor, which uses steam and heat supplied by an external boiler. By the pressurized steam, the cell walls of the waste break and effectively release the internal moisture. Then, the dried waste can be mixed with waste vinyls to produce RDF with a higher heating value as high as 6,700 kcal/kg.

Deforestation and Forest land Use in Côte d'Ivoire: Policy and Fiscal Instruments

  • Djezou, Wadjamsse Beaudelaire
    • Journal of Forest and Environmental Science
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    • v.32 no.1
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    • pp.55-67
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    • 2016
  • This paper investigated policies that drive the sustainable management of Ivorian forest which disappear at an annual rate of 250000 hectares. Based on an inter-temporal model for optimum allocation of forest land to three competing uses, the article found that sustainability depends on the incentive structure, of which forest taxes and fees are a key, though obviously not the sole, component. The study proposed to increase the area fee level by accounting for environmental externalities generated by forest harvesters and farmers. The paper showed that the area fee is a decreasing function of the forest natural rate of regeneration and the reconversion rate of agricultural surfaces. Finally, at the given forest natural rate of regeneration and the reconversion rate of agricultural surfaces, the model argued that the area fee need to be progressive (arithmetic progression) in the context of ecological equilibrium break while it should remain constant in normal situation.

Measurement of Inward Turbulent Flows in a Rotating with Square Cross-Section $90^{\circ}$ Duct (회전하는 정사각단면 $90^{\circ}$ 곡덕트 내 내향 난류유동 측정)

  • Kim, Dong-Chul;Chun, Kun-Ho;Choi, Young-Don
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.627-632
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    • 2000
  • Developing turbulent flows in a rotating 90 degree bend with square cross-section were measured by a hot-wire anemometer. The six orientation hot-wire technique was applied to measured the distributions of 3 mean velocities and 6 Reynolds stress components. Effects of Coriolis and centrifugal forces caused by the curvature and rotation of bend on the mean motion and turbulence structures were experimentally investigated Productive addition of Coriolis and centrifugal forces to the outward radial direction in the entrance region of bend increases the secondary flow intensity according to the rotational speeds. However, after 45 degree of bend, centrifugal force due to the rotation of bend may promote the break down of counter rotating vortex pair into multi-cellular pattern, thereby decreasing the production rate of turbulence energy and Reynolds stresses.

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Design of Airborne Terminal System for Joint Tactical Data Link System Complete Data-link

  • Choi, Hyo-Ki;Yoon, Chang-Bae;Hong, Seok-Jun
    • Journal of Positioning, Navigation, and Timing
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    • v.9 no.2
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    • pp.139-147
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    • 2020
  • In this paper, design measure were proposed for the construction of terminal systems for airborne platforms, which are key element in the Joint Tactical Data Link System (JTDLS) complete system. The Korean perfect tactical data link (JTDLS) is a communication system to establish an independent tactical data link network and needs to develop a MIDS-LVT (Link-16) communication terminal for datalink. Once a Ground/Navy JTDLS terminal system is established around airborne platform, it will be possible to break away from reliance on NATO-based tactical data link joint operations and establish independent Korean surveillance reconnaissance real-time data sharing and tactical data link operations concepts. in this paper, the essential development elements of airborne platform mounting and operable JTDLS terminals are presented, and the concept of system design is proposed to embody them. Further, improved system performance was analyzed by applying the concepts of complex relative navigation system and Advanced TDMA protocol for the deployment of airborne tactical datalink networks.

Kinetics and Mechanism of the Pyridinolysis of Diisopropyl Thiophosphinic Chloride in Acetonitrile

  • Hoque, Md. Ehtesham Ul;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • v.32 no.12
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    • pp.4387-4391
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    • 2011
  • The kinetic studies on the pyridinolysis of diisopropyl thiophosphinic chloride have been carried out in acetonitrile at $55.0^{\circ}C$. The free energy correlations for substituent X variations in the X-pyridines are biphasic concave upwards with a break point at X = 3-Ph. A concerted SN2 mechanism is proposed with a change of the attacking direction of the X-pyridine from a frontside attack for the strongly basic pyridines to a backside attack for the weakly basic pyridines. The factors to determine the rates and thio effects on the rates for the pyridinolyses of thiophophinic chloride, chlorothiophosphate, phosphinic chloride, phosphonochloridothioate, and chlorophosphate systems are briefly reviewed on the basis of the magnitude of the positive charge of the reaction center P atom and steric effects of the two ligands.