• Title/Summary/Keyword: MIL-125

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A Study on the Electromagnetic Pulse Shielding Effect of Concrete Wall Sprayed with Cu-based Metal (Cu계 금속을 용사한 콘크리트 벽체의 전자파 차폐 성능에 관한 연구)

  • Jang, Jong-Min;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.11a
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    • pp.18-19
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    • 2020
  • The ElectroMagnetic Pulse (EMP) destroys social infrastructure at once and causes social chaos. However, currently major infrastructures are constructed of concrete that does not have electromagnetic shielding performance. In this study, using the arc metal spraying method is used to evaluate the shielding performance and construction performance of concrete. The electro-magnetic shielding effect is measured by fabricating a shielding room with reference to MIL-STD-188-125, and the construction performance is evaluated by measuring the adhesion strength of thin metal sprayed film-concrete. As a result of the study, when the metal spraying method is applied, the shielding effect is higher than that of the special electro-magnetic shielding concrete, and it is considered to be more economical than the existing metal plate (3~5 mm).

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Development of Full-scale Airframe Durability Test Technique (항공기 전기체 내구성시험 기법 개발)

  • Shul, Chang-Won;Yang, Myung-Seog;Lee, Kee-Bhum;Jung, Jae-Kwon;Kang, Hui-Won;Lee, Kyung-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.6
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    • pp.117-125
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    • 2004
  • This paper describes the test technique for the full-scale airframe durability test according to the military handbook(MIL-HDBK-1530) and ASIP(Aircraft Structure Integrity Program) to evaluate structural integrity and to obtain basic data for IPA(Initial Production Approval) of the Korean advanced trainer(T-50). This paper covers the full-scale airframe floating setup technique, the optimized test load simulation method, test rig design technique, test setup design and installation techniques, test safety device design and operation technique, and durability test results. As 1st life durability test was successfully performed, it was confirmed that this method is available in a full-scale airframe structural test.

An Experimental Study on the Development of Electromagnetic Shielding Concrete Wall for Shielding High-altitude Electromagnetic Pulse (HEMP) (고고도 전자기파(HEMP)차폐를 위한 전자파 차폐 콘크리트 벽체 개발에 관한 실험적 연구)

  • Choi, Hyun-Jun;Kim, Hyung-Chul;Lim, Sang-Woo;Lee, Han-Seung
    • Journal of the Korea Concrete Institute
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    • v.29 no.2
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    • pp.169-177
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    • 2017
  • Rather than causing damage from heat, blast, and radiation of a regular nuclear weapon, recently, it is predicted that North Korea has been inventing high altitude electromagnetic pulse (HEMP) missile in order to incapacitate electronic equipment. HEMP shielding facility is used for military purpose today. Despite the electromagnetic shielding effects from high quality compression plates, problems may include such as the possibility of electromagnetic influx resulting in the welding of the compression plates, and difficulties and high cost of construction. Therefore, in this study, a high electrical conducting material was added to the concrete experimental subject to ensure the shielding effect through electromagnetic waves to for the concrete structure, instead of building a shielding facility separately for the structure. Also, among the experimental subjects, 100 ${\mu}m$ of Iron-Aluminum alloy metal spraying coat was applied to two types with the highest shielding effect, and to two types with the lowest shielding effect. The result of the experiment indicates that experimental subjects added with a high electrical conductivity material did not meet the minimum shielding criteria of MIL-STD-118-125-1 standard, but all the experimental material applied to the metal spraying coating satisfied the minimum shielding criteria. In conclusion, it is considered that 100 µm of Iron-Aluminum alloy metal spraying coat contains high efficiency in the HEMP shielding.

Analysis of Low-Frequency Magnetic SE of a Metal Plate: Diffusion and Slot Effects (도체 판의 자기장 차폐효과 분석: 확산과 슬롯 효과)

  • Park, Hyun Ho;Kwon, Jong Hwa
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.4
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    • pp.324-327
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    • 2019
  • This study analyzes the low-frequency magnetic shielding effectiveness (SE) of a metal plate, in terms of diffusion and slot effects, by conducting a numerical simulation and implementing an analytical solution. When the metal has a low conductivity, the SE is dominated by the diffusion effect. However, when the conductivity and frequency both increase, the slot has a major influence on the SE. These results can be used as guidelines in the shielding design and SE requirements of electromagnetic pulse protection facilities.

Evaluation on High Altitude Electromagnetic Pulse(HEMP) Protection Performance of Carbon Nanotube(CNT) Embedded Ultra-High Performance Concrete(UHPC) (탄소나노튜브(CNT)를 혼입한 초고성능 콘크리트(UHPC)의 고고도 전자기파(HEMP) 방호성능 평가)

  • Jung, Myungjun;Hong, Sung-gul
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.2
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    • pp.151-161
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    • 2019
  • In this study, to evaluate the High Altitude Electromagnetic Pulse(HEMP) protection performance of UHPC/CNT composites by the content of Carbon nanotubes(CNTs), Electromagnetic Shielding Effectiveness(SE) test was performed based on MIL-STD-188-125-1. And the results were verified by applying the Antenna theory. In the case of UHPC with a thickness of 200 mm mixed with 1 % CNT of cement weight, the SE was 28.98 dB at 10 kHz and 45.94 dB at 1 GHz. Then the Scabbing limit thickness for bullet proof was computed based on the result of compressive strength test which was 170 MPa, and it was examined whether it satisfied the HEMP protection criteria. As a result, the required HEMP shielding criteria were satisfied in all frequency ranges as well as the scabbing limit thickness was reduced by up to 43 % compared with that of ordinary concrete.

Die deutsche Sprache der 'Wende' ('전환기'의 독일어)

  • Kim Tae-Seong
    • Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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    • v.10
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    • pp.125-154
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    • 2004
  • Diesel Beitrag befasst sich mil der Sprache in gesellschaftlichen Umbruchssituationen aus der Perspektive einer spezifisch linguistischen Fragestellung. Im Zentrum der Untersuchung steht der Wandel der Sprachverwendung unter den Bedingungen der Demokratisierung der DDR und der Vereinigung mil der BRD seit der Wende 1989/90. Dieser Wandel wird am Beispiel der Lexik, und anhand von Losungen bzw. Demo-Spruchen konkretisiert. Im Zuge der 'Wende' sind $f\"{u}r$ beide Kommunikationsgemeinschaften - $\"{u}berwiegend$ aber $f\"{u}r$ die der neuen $Bundesl\"{a}nder$ - Neologismen in Gebrauch gekommen. Am bekanntesten sind: 'Mauerspecht', 'Wendehals', 'Moniagsdemo' und 'Stasi-Akte' usw. Andererseits wurden im Verlauf der Wende zahireiche Bezeichnungen, insbesondere $f\"{u}r$ $aufgel\"{o}ste$ Institutionen der DDR sowie viele verwaltungsspezifische $W\"{o}lfer$, historisiert. An Textbeispielen der Losungen des Herbstes 1989 werden uns die Dynamik sprachlicher Strukturen auf der einen Seite und die sich verandernden gesellschaftlichen $Verh\"{a}ltnisse$ in der $\"{o}ffentlichen$ Kommunikation der ehemaligen DDR auf der anderen Seite vol Augen gefuhrt. Verglichen mit den zum 1. Mai bekannt gegebenen of nziellen SED-Losungen, sind die Aktanten der Demo-Spruche das Volk, teils als Individuen und teils als spontan gebildete Gruppen. Im Unterschied zu den 'allen' offiziellen Losungen $repr\"{a}sentieren$ die Demo-$Spr\"{u}che$ verschiedenartige Sprechhandlungstypen: Nicht nur AUFFORDERN, APPELLIEREN, BEHAUPTEN, sondern auch FRAGEN, BESCHIMPFEN, DROHEN, $GR\"{U}{\ss}EN$usw. Gleichzeitig $\"{u}bernehmen$ sie viele Textmuster als sprachliche Stilmittel aus fem Bereich anderer Spruch- und Kurztextgattungen, wie zum Beispiel Sprichwort, Kinderreim, Aphorismus, Anspielung und verwenden auch Zitate. Auf diese Weise linden sich in den Wende-Losungen zahlreiche Belege $f\"{u}r$ intertextuelle $Bez\"{u}ge$. So schaffen diese Losungen $schlie{\ss}lich$ eine neue Qualitat des $\"{o}ffentlich-politischen$ Diskurses in der Gesellschaft. Am Rande der Untersuchungen haben wir $f\"{u}r$ das Deutsch in Ost und West festgestellt: $Bem\"{u}hungen$ der $Ann\"{a}herung$ und des sprachlich-kornrnunikativen Ausgleichs findet man seit der Wende 1989/90 eher auf der Seite der Ostdeutschen. Die sprachlichen Differenzierungen zwischen Ost- und Westdeutschland waren vornehmlich lexikalischer An. Es ist aber anzunehmen, dass es heute weniger die Sprache selbst ist als vielmehr das unterschiedliche Kommunikationsverhalten zwischen Ost- und Westdeutschen, das die Verstandigung zwischen Ost- und Westdeutschen schwierig zu machen scheint.

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Electromagnetic Pulse Shielding Effectiveness and Construction Availability of Cast-In-Place Structures Using Corrugated Metal-Plates

  • Kim, Suk Bong;Yoon, Sangho;Min, Gyung Chan;Ahn, Sungjin;Park, Young Jun
    • Journal of the Korea Institute of Building Construction
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    • v.13 no.1
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    • pp.84-89
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    • 2013
  • This study aims to examine the effectiveness of electromagnetic pulse shielding in cast-in-place protective shelters using corrugated metal-plates, and then reviews their usability for the Republic of Korea Army. The Korea Corps of Engineering has evaluated corrugated metal-plates as a construction material for cast-in-place structures, which have to defend against mechanical impacts as well as electromagnetic pulses. Corrugated metal-plate is known as a superb mechanical protective material, so much so that it has been employed in ammunition magazines and artillery platforms in the armed forces. Moreover, as a metal, such as steel and copper, it is universally recognized as one of the most effective electromagnetic pulse shielding materials. In addition to effectively shielding from electromagnetic pulses and protecting against mechanical impacts, corrugated metal-plates should prove to be an appropriate construction material for the cast-in-place protective shelter in terms of construction availability and economic feasibility. The shielding effectiveness of the suggested structures is examined based on MIL-STD 188-125-1. A few frequency bands need an increase of 15~30dB in shielding effectiveness because of unbidden apertures caused by flaws associated with welding, assembling, and material deformation. However, allowing for the approximately 40dB of shielding provided by soil; the examined structure, which is buried underground, can offset its shortcomings sufficiently.

Evaluation of friction of ceramic brackets in various bracket-wire combinations (브라켓 각도 변화에 따른 세라믹 브라켓의 마찰력 측정)

  • Cha, Jung-Yul;Kim, Kyung-Suk;Kim, Dong-Choon;Hwang, Chung-Ju
    • The korean journal of orthodontics
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    • v.36 no.2 s.115
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    • pp.125-135
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    • 2006
  • The purpose of this study was to measure and compare the level of frictional resistance generated from three currently used ceramic brackets; 1, Crystaline $V^{(R)}$, Tomy International Inc., Tokyo, Japan; 2, $Clarity^{(R)}$, 3M Unitek, Monrovia, CA, USA; 3, $Inspire^{(R)}$, Ormco, Orange, CA, USA; with composite resin brackets, Spirit, Ormco, Orange, CA, USA; and conventional stainless steel brackets, Kosaka, Tomy International Inc., Tokyo, Japan used as controls. In this experiment, the resistance to sliding was studied as a function of four angulations $(0^{\circ},\;5^{\circ},\;10^{\circ}\;and\;15^{\circ})$ using 2 different orthodontic wire alloys: stainless steel (stainless steel, SDS Ormco, Orange, CA, USA), and beta-titanium (TMA, SDS Ormco, Orange, CA, USA). After mounting the 22 mil brackets to the fixture and $.019{\times}.025$ wires ligated with elastic ligatures, the arch wires were slid through the brackets at 5mm/min in the dry state at $34^{\circ}C$. Silica-insert ceramic brackets generated a significantly lower frictional force than did other ceramic brackets, similar to that of stainless steel brackets. Beta-titanium archwires had higher frictional resistance than did stainless steel, and all the brackets showed higher static and kinetic frictional force as the angulation increased. When the angulation exceeded $5^{\circ}$, the active configuration emerged and frictional force quickly increased by 2.5 to 4.5-fold. The order of frictional force of the different wire-bracket couples transposed as the angle increased. The silica-insert ceramic bracket is a valuable alternative to conventional stainless steel brackets for patients with esthetic demands.

Electromagnetic Wave Shielding Effectiveness Measurement Method of EMP Protection Facility (EMP 방호시설의 전자파 차폐효과 측정 방법)

  • Seo, Manjung;Chi, Seongwon;Kim, Youngjin;Park, Woochul;Kang, Hojae;Huh, Changsu
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.5
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    • pp.548-558
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    • 2014
  • EMP(Electromagnetic Pulse) protection facility was evaluated according to standard of shielding effectiveness. To comply with the standard, transmitting antenna was placed on outside of protection facility and receiving antenna was placed on inside of protection facility. However, measurement is impossible that place does not have enough space between protection facility and external concrete structure. In this paper, we performed a various of tests that put transmitting antenna inside the EMP protection facility in order to find out test method for measuring the shielding effectiveness of electromagnetic wave. Transmitting antenna was placed on inside of the EMP protection facility for measuring the shielding effectiveness to compare and analyze the impact of the position regarding to the transmitting and receiving antenna. As a result of test, in case that transmitting antenna was placed on inside of the EMP protection facility, it was found that test frequency range 10 kHz~1 GHz were occurred overall average difference of ${\pm}4$ dB level.

Assessment of the Electromagnetic Pulse Shield Effectiveness of the Wave-guided Below Cutoff Filled with Water and Oil for Guaranteeing the Operational Sustainment of the Command Post (지휘소 작전지속성 보장을 위한 도파관의 전자기파 차폐성능 향상방안)

  • Yoon, Sangho;Son, Kiyoung;Kim, Suk Bong;Park, Young Jun
    • Journal of the Korea Institute of Building Construction
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    • v.13 no.6
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    • pp.579-584
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    • 2013
  • The stable fueling and water supply should be prerequisites to guarantee the operational sustainment of military command post. Meanwhile, in terms of the operational sustainment, it is verified that the current wave-guided below cutoff (WBC) system cannot satisfy the requirement of control associated with water supply and fueling within the command post. In this study, as the dielectric substance can block electromagnetic pulse (EMP), it was tried to identify the shielding effectiveness of the multi WBCs filled with water and diesel for attenuating the EMP effect using experiment based on the MIL STD 188-125-1. According to the experimental results, used water in the experiment show the shielding effectiveness from around 640 MHz frequency because of minerals contained in the water. Furthermore, it was noted that EMP attenuating strength of the WBC filled with diesel was enlarged from around 1,680 MHz frequency. Resultingly, it could be concluded that it is enough to supply stable water and diesel through the multi WBC to block EMP within the military command post for guaranteeing the military operations sustainment.