• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.3
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• pp.156-164
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• 1999

Two analytical solutions for wave diffraction by a semi-infinite breakwater, which Penney and Price (1952), and Stoker (1957) presented, are rederived. Since in previous works the derivations were skipped or briefly given, in the paper the derivation is brought into focus. Numerical computations of the solutions are presented and solution behavior of Stoker's method due to a number of terms in the series is analyzed.

• The Journal of the Korean Society for Microbiology
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• v.22 no.1
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• pp.23-33
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• 1987

To detect lepotospiral strains which produce hemolysin and determine the optimal condition for assaying hemolysin, we screened reference strains and observed some property of hemolysin. Hemolysin activity was assayed with cell free culture liquids and erythrocyte suspension. The production of hemolysin by local strains isolated in Korea was assayed and compared with that of reference strains. The hemolysin was produced by 18 strains among 38 reference strains and 3 local strains isolated in Korea. The production of hemolysin began with growth of Leptospira cultured in EMJH medium and reached maximum at stationary phase. The optimum temperature for hemolytic activity was $37^{\circ}C$. At lower temperature the activity of hemolysin was decreased progressively. The hemolytic activity was completely inactivated after :30 minutes' exposure at $56^{\circ}C$. Hemolysis pattern was "hot-cold type" which showed increased hemolysis after cold incubation. The hemolysin was most active on sheep erythrocyte and less active on ox, goat, human and guinea pig erythrocyte with the decreasing order.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.665-670
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• 1995

A marine bacterium which produces extracelluar agarase was isolated from sea water. Isolated strain was identified as Pseudomonas sp. by the morphological and biochemical properties (1). HindIII restriction fragment of 3.2 kb from Pseudomonas genomic DNA was cloned into pUC19 to obtain recombinant plasmid pJA1 which enables E. coli JM83 to produce agarase. Most of agarase produced in E. coli was secreted into the culture medium. The enzyme (pJA1) showed the highest agarase activity during the stationary phase (20 hrs) of E. coli. The optimum temperature and pH were 40$\circ$C and 7.8, respectively. Restriction gene map anlaysis revealed that it has different restriction pattern with three kind of agarase gene reported.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.310-316
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• 2001

Poly-3-hydroxybutyrate (PHB) synthase catalyzed the last enzymic step to synthesize the intracellular PHB of Rhodobacter sphaeroides. No PHB was detected when the phbC coding for PhB synthase was interrupted, and its expression was regulated at the level of transcription. The cellular PHB content increased about four- to six-fold during the growth transition from the exponential to the early stationary phase under both aerobic and photoheterotrophic conditions. The PHB content during the aerobic growth seemed to be determined by the PhB synthase activity. However, the PHB synthase activity of photoheterotrophically grown cells did not correlate with the PhB content, suggesting a photoheterotrophic regulation different from the aerobic control. Thus, the PHB content of R. sphaeroides was regulated at the transcription level only under aerobic conditions.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.322-327
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• 2008

1,5-Dihydroxy-3-methoxy-7-methylanthracene-9,10-dione (shiraiarin) is a kind of antitumor and antibacterial anthraquinone, and was produced for the first time from the submerged fermentation of Shiraia bambusicola, as confirmed by ESI-MS and NMR. The production of shiraiarin was significantly influenced when varying the carbon source, and a high amount of shiraiarin was only achieved when using lactose. The production of shiraiarin was also stimulated when using $NaNO_3$ as the nitrogen source, whereas other nitrogen sources inhibited its production. Shiraiarin was formed during the stationary phase with a pH value higher than 8. The production of shiraiarin was inhibited by sporulation.

• The Microorganisms and Industry
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• v.27 no.2
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• pp.13-22
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• 2001

방선균은 필라멘트 형태를 띤 대표적인 그램 양성 세균으로서, 다양한 자연환경에 존재하는 대표적인 토양 미생물이다. 방성균이 항생제를 포함한 다양한 구조의 많은 유용 생리활성물질을 생성하며, 이들의 생합성 시기가 세포의 배양상태 및 생장속도와관련이 있다는것은 이미 주지의 사살이다. 비록 방선균은 액체 배양 시에는 정체기((stationary phase)나 낮은 생장속도하에서만 항생제를 생성하며, 고체 배양 시에는 aerial mycelia 로 형태적분화(morphological differentiation)를 시작함과 동시에 생합성을 시작한다고 알려져 있으나, 각 방선균 및 항생제의 종류에 따른 특징적인 조절 기작은 매우 다양한 것으로 알려져 있다. 따라서 특징적인 조절 기작은 매우 다양한것으로 알려져 있다. 따라서 본 총성레서는 항생제 생합성이 조절되는 기작을 지금까지 밝혀진 방선균의 여러 생리적 인자 및 생합성 조절 유전자를 중심으로 정리해 보고자 한다. 항생제 생합성에 관하여 다양한 생리적 인자와 조절 유전자의 특정 및 이들의 상호관계에 대한 종합적인 이해는, 방선균 유래 항생제 조절 기작의 체계적인 규명뿐만 아니라, 방선균을 이용한 유용 생리활성물질의 생산성 향상에도 응용될수 있다는 점에서 매우 중요하다.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.857-860
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• 2005

Several algorithms have been developed for the data processing of spotlight synthetic aperture radar (SAR). In particular, the range migration algorithm (RMA) does not assume that illuminating wavefronts are planar. Also, a high resolution image can be obtained by the RMA. This paper introduces an extension of the original RMA to enable a more efficient airborne SAR data processing. We consider more general motion and scene than the original RMA. The presented formulation is analyzed by using the principle of the stationary phase. Finally, the extended algorithm is tested with numerical simulations using the pulsed spotlight SAR.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.10
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• pp.141-151
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• 1994

this paper describes the design and implementation of a RISC processor for embedded control systems. This RISC processor integrates a register file, a pipelined execution unit, a FPU interface, a memory interface, and an instruction prefetcher. Its characteristics include both single cycle executions of most instructions in a 2 phase 20 MHz frequency and the worst case interrupt latency of 7 cycles with the vectored interrupt handling that makes it possible to be applicable to the real time processing system. For efficient handling of multi-cycle instructions, data stationary hardwired control scheme equippedwith cycle counter was used. This chip integrates about 139K transistors and occupies 9.1mm$\times$9.1mm in a 1.0um DLM CMOS technology. The power dissipation is 0.8 Watts from a 5V supply at 20 MHz operation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.5
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• pp.359-362
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• 2001

The production of an extracellular polysaccharide, EPS-R, from the marine bacterium Hahella chejuensis was investigated at various aeration rates in a batch culture. Higher aeration rate resulted in enhanced EPS production and increased the viscosity of the culture broth. At an aeration rate of 1.5 vvm, EPS-R (12.2 g/L) was obtained with a yield (Y$\_$p/s) of 0.6 from the STN medium after 72 h of cultivation. The H. chejuensis cells changed rod morphology to a short-rod form in the stationary growth phase.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.165-166
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• 2008

Bistatic spotlight synthetic aperture radar(BSSAR) with single track configuration uses the transmitter and the receiver which travel along the single track such as the leader-follower. For the BSSAR imaging, we modify the range migration algorithm. In time domain, we make the monostatic SAR using shifting of path, Then, in frequency domain, we compensate the separated distance between the scene center and the flight path using the principle of the stationary phase (PSP).