• Advances in aircraft and spacecraft science
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• v.3 no.3
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• pp.317-330
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• 2016

Nowadays, the interest of aerospace and automotive industries on virtual testing of medium-frequency vibrational behavior of shallow shell structures is growing. The development of software capable of predicting the vibrational response in such frequency range is still an open question because classical methods (i.e., FEM, SEA) are not fully suitable for the medium-frequency bandwidth. In this context the Variational Theory of Complex Rays (VTCR) is taking place as an ad-hoc technique to address medium-frequency problems. It is a Trefftz method based on a weak variational formulation. It allows great flexibility because any shape function that satisfies the governing equations can be used. This work further develops such theory. In particular, orthotropic materials are introduced in the VTCR formulation for shallow shell structures. A significant numerical example is proposed to show the strategy.

• Journal of Power Electronics
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• v.9 no.6
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• pp.866-873
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• 2009

In general, the output voltage level of a PV array varies widely at various irradiances and temperatures. The MPP (Maximum Power Point) range of a medium- or high-power PV PCS is normally 450~830Vdc or 300~600Vdc. This means the PV PCS should operate in a wide range of modulation indexes. The PV PCS should satisfy the harmonic current requirement that the TDD (Total demand distortion) shall not exceed 5%. This paper proposes a new PWM control method for a medium- or high-power PV PCS which increases the efficiency of power conversion in all operation ranges with acceptable harmonic ripple currents. This paper compares and analyzes appropriate PWM schemes for the PV PCS in the view points of conversion efficiency and current harmonics.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3872-3877
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• 1975

This study was conducted to examine the effects of the change of cap hole diameter and pressure on the travelling distance and the sprayed particle size for the medium range nozzle. The results of this study are summarized as follows; 1) The effective travelling distance was about from 1 meter to 8 meters and centro-position of the travelling distance was about 3 or 5 meters. 2) Main effect of change of cap hole diameter for the travelling distance was a slight convex quadratic curve. 3) Main effect of change of pressure increased linearly, its increasing rate about 1.6 was large. 4) Sizes of sprayed particles were less than 250${\mu}$ generally and the sizes decreased according to the increasing of travelling distance. 5) Changes of diameter of sprayed particles by cap hole diameter increased in accordance with increasing of cap hole diameter. 6) Changes of diameter of sprayed particles by the groove depth of swirl plate was very slight.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.1
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• pp.64-69
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• 2004

In recent years, Medium size high speed Ro-Pax vessel has appeared at European sea and especially Agean sea is a center of operating in this type of Ro-Pax. This vessel operates its high Froude number range and requires higher engine power due to considerably increased resistance in comparing to large Ro-Pax in high speed range. SHI has investigated this kind of high speed Ro-Pax in accordance with market requirements and developed more advanced vessel to meet the future market needs. Process of hull form development, model test results and design of general arrangement results are introduced in this paper.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.3
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• pp.69-81
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• 1997

Up to now 5 Voith Sulzer paper machines with multi-layer headbox and Gapfor-mer are sucessfully running on papckaging papers. Linerboard, testliner and corugating medium is produced in the basis weight range from 105 to 275 $g/m^2$ at machine speeds up to 900 m/min. The nest one, starting up in Oct. ｀96 in Germany, will be the world＇s fastest paper machine for packaging papers. The 5.6 m wide machine is designed for a maximum operating speed of 1200 m/min. Approx. 220.000 tons of corrugating medium and testliner based on 100% waste paper in the basis weight range from 90 to 160 $g/m^2$ will be produced each year. An expansion stage planned for the future is intended to increase annual output to 280.000 tons. This machine will not only be the fastest one for packaging papers, it also comprises all described innovative key components which are available today in order to fulfill growing demands of the future with regard to quality and productivity. The concept of this advanced machine is shown in Fig. 9.

• KSBB Journal
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• v.18 no.2
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• pp.94-99
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• 2003

The effect of medium composition on the production of bacterial cellulose (BC) by Gluconacetobacter hansenii PJK was investigated. The addition of yeast extract and peptone in the medium increased the production yield (Y/sub p/s/) of BC. The amount of BC produced by G. hansenii PJK was constant if the initial pH of the medium was in the range 4.5 to 6.0. Strains from the supernatant of the culture medium produced more BC than those from inside the BC. BC production was dependent on glucose metabolism, and the addition of fructose or lactate as a carbon source converted cells to Cel/sup -/ mutants. Cel/sup -/ mutants produced by the addition of fructose or lactate to the medium caused 73% or 30% decreases in BC production, respectively. The addition of succinate, which is one of the constituents of the TCA cycle, did not affect the production of BC.

• 전기의세계
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• v.29 no.8
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• pp.519-523
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• 1980

The traditional mechanical manometer is improved to develop more convenient and precise manometer in continuous measurement of the gas pressure in medium-low vacuum range (1x10$^{-1}$ -10 Torr.) Glass (solid) is used as a detector material of the improved manometer. Using the strain gauge adhered to thin glass board, mechanical strain corresponding to variation of pressure in measurement system is converted into quantity of electricity, and the quantity of electricity is amplified. Experiments have also shown that the improved manometer have more advantages in reproducibility, measured sensibility, and responsible velocity than taditional one.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1209-1213
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• 1991

This paper describes a new method for performance improvement ultrasonic ranging system using V40 controller. Detectable range of ultrasonic ranging system depends on transducer frequency and bandwidth of the receiver, and damping of the transducer, etc. Conventional ranging systems are somewhat inaccurate because they do not have capability of compensating changes in medium condition. The novel ranging system overcomes this disadvantage by placing in the same medium a dummy sensor functioning as a standard calibrating instrument and by providing data processing capability using V40 controller.

• Toxicological Research
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• v.5 no.1
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• pp.53-59
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• 1989

A mycotoxin Patulin, isolated from apple juice medium cultured with Penicillium patulum NRRL5259, was purified through acid aluminum column using ethyl ether as eluent. The yield of purified patulin crystal was 3mg/ml culture medium after 8 days of shaking culture at 28C. The growth rate of Escherichia coli K12JM103 infected with bacteriophage M13 was decreased by patulin at the concentration range of 1Mug/ml to 10Mu/nl. ED50 of patulin for the bacterial growth was 4.5Mug/ml and 10Mug/ml of patulin caused maximum inhibitory effect (60% inhibition) on the growth.

• Information and Communications Magazine
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• v.19 no.9
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• pp.18-30
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• 2002

노변통신 방식은 ITS시스템에서 매우 중요한 역할을 수행하며 주로 DSRC라는 명칭으로 개발되었고, 최근에 CALM(Communications Air-interface Long and Medium Range)라고 하여 좀 더 긴 통신거리의 방식이 논의되고 있다. 본 논문에서는 세계의 주요 DSRC 통신 규격과 주파수 분배 현황에 대해서 기술하고 있다.