• 생약학회지
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• 제12권4호
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• pp.185-189
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• 1981

The quality inspection was made on commercial Korean ginseng extract (Company A, B, C, D, E, F, G and H), particularly on samples available in Seoul market area. The results were as follews: 1) Among the ginseng extract products out of eight different manufactures, the moisture content of D company's product showed 46.5%, and other companys' met with the moisture standard for ginseng extracts. And protein, fat, ash, fiber and total sugar were about $9.87{\sim}21.07%,\;0.46{\sim}1.62%,\;6.55{\sim}7.88%,\;0{\sim}0.15%\;and\;58.58{\sim}76.74%$, respectively. And residue of D and F company products showed 3.25% and 3.61% which exceed the standard, and other company products met with residue test specifications. 2) The contents of ginseng saponins were 16.16% and 13.12%, respectively, for the C and H company products. However, other company's showed below 9%. By fractional distribution of ginseng saponins, it is supposed to be white ginseng and lateral ginseng that were mostly used as raw materials for ginseng extract manufacturing.

• 한국의류학회지
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• 제41권4호
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• pp.771-781
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• 2017

The helmet is an imperative personal protective equipment. This protective device must be able to guard the human head against potential risks. Helmets are classified according into the purpose of use; therefore, the required performance and specifications depend on the type of products. Military helmets are intended to protect the wearer's head from bullets and shrapnel. Generally, lightweight super fibers and fiber reinforced composite materials are used as helmet shell materials, and NIJ STD of U.S. Department of Justice is most widely used as international standard related to bulletproof helmets. Safety helmets are widely used for industrial application and sports leisure. In general, the performance of shock absorption must be ensured, and various lining systems are applied in material, design, and combination methods. Evaluation standards have also been classified and strictly controlled for each purpose; therefore, it is difficult to certify with the existing standards such as the recently developed convergence helmets. However, it is possible to launch the product through a separate national integrated certification procedure.

• 설비공학논문집
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• 제3권3호
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• pp.176-185
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• 1991

Pressure drop and flow characteristics through a filter medium have been investigated numerically. A basic model similar to the filter employed in a hard disk drive was established so that the inflow velocity was 0.1 m/s and the box size was $40mm{\times}50mm{\times}30mm$. The filter medium specifications were 0.38mm of thickness, $1{\mu}m$ of fiber diameter, 0.05 of packing density. And the filter medium was pleated by 10 within the filter box. Twenty-one sets of calculation were performed with different inlet velocities, pleated numbers, and packing densities from the basic model. As the result, it was found that the velocity after filter medium had maximum value at the rear of the upstream pleated line, but had minimum value at the rear of the downstream pleated line. This made the velocity distribution have sinusoidal form immediately after the filter medium. As the inlet velocity increased, the pressure drop increased linearly. But as the packing density increased the pressure drop increased quadratically.

• ETRI Journal
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• 제35권2호
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• pp.245-252
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• 2013

In this work, we study the physical layer solutions for 10-gigabit-capable passive optical networks (PONs), particularly for an optical link terminal (OLT) including a 10-Gbit/s electroabsorption modulated laser (EML) and a 2.5-Gbit/s burst mode receiver (BM-Rx) in a novel bidirectional optical subassembly (BOSA). As unique features, a bidirectional mini-flat package and a 9-pin TO package are developed for a 10-gigabit-capable PON OLT BOSA composed of a 1,577-nm EML and a 1,270-nm avalanche photodiode BM-Rx, including a single-chip burst mode integrated circuit that is integrated with a transimpedance and limiting amplifier. In the developed prototype, the 10-Gbit/s transmitter and 2.5-Gbit/s receiver characteristics are evaluated and compared with the physical media dependent (PMD) specifications in ITU-T G.987.2 for XG-PON1. By conducting the 10-Gbit/s downstream and 2.5-Gbit/s upstream transmission experiments, we verify that the developed 10-gigabitcapable PON PMD prototype can operate for extended network coverage of up to a 40-km fiber reach.

• Computers and Concrete
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• 제27권5호
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• pp.437-445
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• 2021

Retrofitting of structures has gained importance over the recent years. Particularly, Reinforced Cement Concrete (RCC) column strengthening has become a challenge to the structural engineers, owing to the risks and complexities involved in it. There are several methods of RCC column strengthening viz. RCC jacketing, steel jacketing and Fiber Reinforced Polymer (FRP) wrapping etc., FRP wrapping is the most promising alternative when compared to the others. The large research database shows FRP wrapping, through lateral confinement, improves the axial load carrying capacity of the columns under concentric loading. However, its confining efficiency reduces under eccentric loading. Hence a relative newer technique called Near Surface Mounting (NSM), in which Carbon FRP (CFRP) strips are epoxy grouted to the precut grooves in the cover concrete of the columns, has been thrust domain of research. NSM technique strengthens the column nominally under concentric load case while significantly under eccentric case. A novel configuration of NSM in which the vertical NSM (VNSM) strips are being connected by horizontal NSM (HNSM) strips was numerically investigated under both concentric and eccentric loading. It was found that the configuration with 6 HNSM strips performed better under eccentric loading than under concentric loading, while the configuration with 3 HNSM strips performed better under concentric loading than under eccentric loading. Hence an optimum of 4 HNSM strips is recommended as strengthening measure for the given column specifications. It was also found that Aluminum alloy cannot be used instead of CFRP in NSM applications owing to its lower mechanical properties.

• Steel and Composite Structures
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• 제41권6호
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• pp.887-898
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• 2021

This paper presents a simplified model to capture the nonlinear behavior of steel frames depending on the spread of plasticity method. New interaction formulae were derived to evaluate the plastic strength for I-shaped steel sections under uniaxial bending moment and axial compression load. Also, new empirical formulae were derived to evaluate the tangent stiffness modulus of steel I-shaped cross-sections considering the effect of the residual stresses suggested by the specifications in European Convention for Construction Steelworks (ECCS). The secant stiffness which depends on the tangent modulus is used to evaluate the internal forces. Based on stiffness matrix method, a finite element analysis program was developed for the nonlinear analysis of space steel frames using the derived formulae. Comparison between the proposed model results with those given by the fiber model shows very good agreement. Numerical examples were introduced to verify, check the accuracy, and evaluate the efficiency of the proposed model. The analysis results show that the new proposed model is accurate and able to minimize the solution time.

• 콘크리트학회논문집
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• 제24권5호
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• pp.543-551
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• 2012

도로포장의 내구 연한이 기대수명에 비하여 짧아지고 있어 최근 다기능 복합포장 개발 연구가 진행중이다. 이 연구에서는 아스팔트 표층을 구성하기 위한 빈배합 콘크리트 기층재료로 활용하기 위하여 재료적인 측면을 개선시키는 방안과 섬유보강재를 추가하여 포장체를 보강하는 연구방안으로 역학적 특성을 분석 연구를 수행하였다. 빈배합 콘크리트의 경우 그 특성상 다짐의 수준이 강도 등의 특성 발현에 많은 영향을 미치게 된다. 하지만 현재 국내에서는 기층의 다짐관리에 관한 세부적인 기준이 미비하므로 자체적으로 다짐방법 및 수준을 정하여 제시하였다. 실내 및 현장 실험 결과 압축강도기준은 재령 7일에 5 MPa로서 모든 빈배합 콘크리트의 변수가 이를 충분히 만족시키는 것으로 나타났으며 현장배합 강도의 경우 일반적인 수화반응에 의한 강도의 증진효과 보다는 롤러의 다짐에너지에 의한 강도의 증진효과가 지배적으로 작용하였을 것으로 판단된다.

• 한국광학회지
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• 제14권3호
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• pp.331-337
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• 2003

본 연구는 이중 이온빔 스퍼터링 증착법으로 제작한 채널 간격 50 ㎓ 광통신용 협대역 투과 필터에 관한 연구이다. Ta$_2$ $O_{5}$ 단층박막의 특성 분석을 통해 공정 조건을 최적화 하였으며, DPS 필터 예비 증착을 통해 0.1 nm 이하의 박막두께 균일성을 확보하였다. 1/4 파장 광학박막 두께를 기본으로 하여 총 216층으로 구성되고 4개의 간격층을 갖는 채널 간격 50 ㎓ 협대역 투과 필터를 설계하였고, 파장 가변 레이저를 사용한 비접촉 광학 두께 제어 시스템을 사용하여 증착하였다. 박막 증착시 발생하는 스트레스를 줄이기 위하여 열팽창 계수가 큰 유리 기판을 사용하였으며, 비접촉 광학 두께 제어 시스템의 오차를 줄이기 위하여 협대역 투과 필터의 제작에 앞서 기판의 뒷면에 무반사 증착을 수행하였다. 이렇게 제작된 채널 간격이 50 ㎓인 협대역 투과 필터의 광학 특성은 삽입 손실이 0.40 ㏈, 잔물결이 0.20 ㏈이며,-0.5 ㏈와 -25 ㏈에서의 투과 대역폭이 각각 0.20 nm, 0.60 nm로 광통신에서 사용되는 사양을 만족하였다.하였다.

• 천문학회보
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• 제40권1호
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• pp.52.3-53
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• 2015

The GMT-Consortium Large Earth Finder (G-CLEF) is a fiber-fed, optical band high dispersion echelle spectrograph that selected as the first light instrument for the Giant Magellan Telescope (GMT). This G-CLEF has been designed to be a general- purpose echelle spectrograph with the precisional radial velocity (PRV) capability of 10 cm/sec as a goal. The preliminary design review (PDR) was held on April 8 to 10, 2015 and the scientific observations will be started in 2022 with four mirrors installed on GMT. We have been participating in this preliminary design study in flexure control camera (slit monitoring system), calibration lamp sources, dichroic assembly and the fabrication of the proto-Mangin Mirror. We present the design concept on the parts KASI undertaken, introducing the specifications and capabilities of G-CLEF.

• 전자공학회논문지
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• 제53권8호
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• pp.119-126
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• 2016

본 논문에서는 의복용 무선전력전송 시스템을 구축을 위한 평면형 직물공진기를 제안하고, 공진기에 사용된 의복용 직물기판의 재질별 특성을 분석하였다. 평면형 직물공진기는 공진주파수가 1-10 MHz가 되도록 직물기판 위에 전도성 물질로 루프 및 코일을 평면 설계하였다. 의복용으로 많이 사용되고 있는 폴리에스테르 섬유와 면을 직물기판으로 사용하였으며, 평면 루프와 코일은 동테이프(copper tape)와 실버페이스트(silver paste)로 설계하였다. 자기공진형 무선전력전송 시스템에 적용된 직물의 재질별 특성을 분석하기 위해 송신부와 수신부를 대칭으로 설계하였다. 실험 결과, 낮은 유전상수 및 비교적 두꺼운 두께를 가진 직물기판과 표면저항이 작은 도체성 재질의 패턴(루프 및 코일)으로 제작되었을 때, 의복용 무선전력전송 시스템이 높은 전송효율을 보였다. 본 연구를 통해 제안된 평면형 직물 공진기는 무선전력전송 기술의 영역을 의복용으로 넓힐 수 있는 가능성을 보여주었다.