• Title/Summary/Keyword: formation flight

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Polynomial-time Greedy Algorithm for Anti-Air Missiles Assignment Problem (지대공 미사일 배정 문제의 다항시간 탐욕 알고리즘)

  • Lee, Sang-Un
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.19 no.3
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    • pp.185-191
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    • 2019
  • During the modern battlefields of multi-batches flight formation attack situation, it is an essential task for a commander to make a proper fire distribution of air defense missile launch platforms for threat targets with effectively and quickly. Pan et al. try to solve this problem using genetic algorithm, but they are fails. This paper gets the initial feasible solution using high threat target first destroying strategy only use 75% available fire of each missile launch platform. Then, the assigned missile is moving to another target in the case of decreasing total threat. As a result of experiment, while the proposed algorithm is polynomial-time complexity greedy algorithm but this can be improve the solution than genetic algorithm.

Real-time Transformation of FePt Nanoparticles to L10 Phase by the Gas Phase Synthesis (기상합성공정을 이용한 FePt 나노입자의 실시간 L10 상변화)

  • Lee, Ki-Woo;Lee, Chang-Woo;Kim, Soon-Gil;Lee, Jai-Sung
    • Korean Journal of Metals and Materials
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    • v.49 no.1
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    • pp.46-51
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    • 2011
  • Real-time formation of $L1_0$ phase of FePt nanoparticles in the gas phase during ultrasonic-spray pyrolysis is first discussed in the present study. Without any post heat treatment, $L1_0$ phase of FePt nanoparticles appeared at the temperature above $900^{\circ}C$ in the gas phase synthesis. X-ray diffractometry (XRD) and transmission electron microscopy (TEM) studies revealed that FePt nanoparticles less than 10 nm in size contained small volume of $L1_0$ fct phase. However, in other samples obtained at the temperature below $900^{\circ}C$, iron oxide phase co-existed and no evidence of phase transformation was found. Thus, it is anticipated that the time of flight of particles required for crystallization and phase transformation was extended according to the increase of the collision rate. Finally, magnetic properties represented by coercivity and saturation magnetization and functional groups on the particle surface were discussed based on VSM and FT-IR results.

NUMERICAL ANALYSIS FOR TURBULENT FLOW AND AERO-ACOUSTICS AROUND A THREE DIMENSIONAL CAVITY WITH HIGH ASPECT RATIO (3차원 고세장비 공동 주위의 난류유동 및 음향 특성에 관한 수치적 연구)

  • Mun, P.U.;Kim, J.S.
    • Journal of computational fluids engineering
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    • v.15 no.2
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    • pp.7-13
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    • 2010
  • Flight vehicles such as wheel wells and bomb bays have many cavities. The flow around a cavity is characterized as an unsteady flow because of the formation and dissipation of vortices brought by the interaction between the free stream shear layer and the internal flow of the cavity. The resonance phenomena can damage the structures around the cavity and negatively affect the aerodynamic performance and stability of the vehicle. In this study, a numerical analysis was performed for the cavity flows using the unsteady compressible three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equation with Wilcox's turbulence model. The Message Passing Interface (MPI) parallelized code was used for the calculations by PC-cluster. The cavity has aspect ratios (L/D) of 5.5 ~ 7.5 with width ratios (W/D) of 2 ~ 4. The Mach and Reynolds numbers are 0.4 ~ 0.6 and $1.6{\times}10^6$, respectively. The occurrence of oscillation is observed in the "shear layer and transient mode" with a feedback mechanism. Based on the Sound Pressure Level (SPL) analysis of the pressure variation at the cavity trailing edge, the dominant frequencies are analyzed and compared with the results of Rossiter's formula. The dominant frequencies are very similar to the result of Rossiter's formula and other experimental datum in the low aspect ratio cavity (L/D = ~4.5). In the high aspect ratio cavity, however, there are other low dominant frequencies of the leading edge shear layer with the dominant frequencies of the feedback mechanism.

NUMERICAL ANALYSIS FOR TURBULENT FLOW OVER A THREE DIMENSIONAL CAVITY WITH LARGE ASPECT RATION (세장비 변화에 따른 3차원 공동 주위의 난류유동 및 음향 특성에 관한 수치적 연구)

  • Mun, P.U.;Kim, J.S.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.11a
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    • pp.13-18
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    • 2009
  • Flight vehicles such as wheel wells and bomb bays have many cavities. The flow around a cavity is characterized as an unsteady flow because of the formation and dissipation of vortices brought about by the interaction between the free stream shear layer and the internal flow of the cavity. The resonance phenomena can damage the structures around the cavity and negatively affect the aerodynamic performance and stability of the vehicle. In this study, a numerical analysis was performed for the cavity flows using the unsteady compressible three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equation with Wilcox's turbulence model. The Message Passing Interface (MPI) parallelized code was used for the calculations by PC-cluster. The cavity has aspect ratios (L/D) of 2.5 ~ 7.5 with width ratios (W/D) of 2 ~ 4. The Mach and Reynolds numbers are 0.4 ~ 0.6 and $1.6{\times}106$, respectively. The occurrence of oscillation is observed in the "shear layer and transient mode" with a feedback mechanism. Based on the Sound Pressure Level (SPL) analysis of the pressure variation at the cavity trailing edge, the dominant frequencies are analyzed and compared with the results of Rossiter's formula. The dominant frequencies are very similar to the result of Rossiter's formula and other experimental data in the low aspect ratio cavity (L/D = ~ 4.5). In the large aspect ratio cavity, however, there are other low dominant frequencies due to the leading edge shear layer with the dominant frequencies of the feedback mechanism. The characteristics of the acoustic wave propagation are analyzed using the Correlation of Pressure Distribution (CPD).

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Recombinant Glargine Insulin Production Process Using Escherichia coli

  • Hwang, Hae-Gwang;Kim, Kwang-Jin;Lee, Se-Hoon;Kim, Chang-Kyu;Min, Cheol-Ki;Yun, Jung-Mi;Lee, Su Ui;Son, Young-Jin
    • Journal of Microbiology and Biotechnology
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    • v.26 no.10
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    • pp.1781-1789
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    • 2016
  • Glargine insulin is a long-acting insulin analog that helps blood glucose maintenance in patients with diabetes. We constructed the pPT-GI vector to express prepeptide glargine insulin when transformed into Escherichia coli JM109. The transformed E. coli cells were cultured by fed-batch fermentation. The final dry cell mass was 18 g/l. The prepeptide glargine insulin was 38.52% of the total protein. It was expressed as an inclusion body and then refolded to recover the biological activity. To convert the prepeptide into glargine insulin, citraconylation and trypsin cleavage were performed. Using citraconylation, the yield of enzymatic conversion for glargine insulin increased by 3.2-fold compared with that without citraconylation. After the enzyme reaction, active glargine insulin was purified by two types of chromatography (ion-exchange chromatography and reverse-phase chromatography). We obtained recombinant human glargine insulin at 98.11% purity and verified that it is equal to the standard of human glargine insulin, based on High-performance liquid chromatography analysis and Matrix-assisted laser desorption/ionization Time-of-Flight Mass Spectrometry. We thus established a production process for high-purity recombinant human glargine insulin and a method to block Arg (B31)-insulin formation. This established process for recombinant human glargine insulin may be a model process for the production of other human insulin analogs.

The Role of Color Identity on Building Airlines's Brand Image (브랜드 연상 형성에 미치는 항공사 컬러 아이덴티티의 역할)

  • Yoon, Moon-Sun;Yang, Guen-Ae;Jin, Chang-Hyun
    • The Journal of the Korea Contents Association
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    • v.15 no.8
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    • pp.119-129
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    • 2015
  • The purpose of this paper is to improve efficiency in establishing brand identity by researching the effect of local airlines' use of color identity on consumer's brand awareness. Case analysis on color image has first been implemented. And then an empirical study has been carried out in order to measure the effects of consumer's brand awareness based on color image and correlation of an airline company's image with its color image on formation of brand image. Airline's use of color identity, associated with color image, plays an important role in consumer's brand association. Also, the importance of color application will be raised identifying that it has a positive impact in establishing domestic airline's brand identity. This will contribute to the domestic airlines in emerging as global leaders with distinct brand identities and competitive edge. Furthermore, this study will suggest continuing research focusing on new aspects in sensuous consumption behavior given that existing researches on airline's brand have been limited to human services, system, and flight operation.

The Antibiosis Action and Rice-Induced Resistance, Mediated by a Lipopeptide from Bacillus amyloliquefaciens B014, in Controlling Rice Disease Caused by Xanthomonas oryzae pv. oryzae

  • Li, Shu Bin;Xu, Shi Ru;Zhang, Rui Ning;Liu, Yuan;Zhou, Ren Chao
    • Journal of Microbiology and Biotechnology
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    • v.26 no.4
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    • pp.748-756
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    • 2016
  • In the present study, a lipopeptide (named AXLP14) antagonistic to Xanthomonas oryzae pv. oryzae (Xoo) was obtained from the culture supernatant of Bacillus amyloliquefaciens B014. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis demonstrated that AXLP14 consisted of surfactin homologs. The minimum inhibition concentration and minimum bactericidal concentration of AXLP14 against Xoo were determined to be 1.25 and 2.50 mg/ml, respectively. At a concentration of 0.613 mg/ml, AXLP14 strongly inhibited the formation of Xoo biofilm. AXLP14 also inhibited the motility of Xoo in a concentration-dependent manner. Applying AXLP14 to rice seedlings significantly reduced the incidence and severity of disease caused by Xoo. In Xoo-infected rice seedlings, AXLP14 strongly and continuously up-regulated the expression of both OsNPR1 and OsWRKY45. In addition, AXLP14 effectively inhibited the Xoo-induced up-regulation of the expression of the abscisic acid biosynthesis gene OsNECD3 and the abscisic acid signalingresponsive gene OsLip9, indicating that AXLP14 may protect rice against Xoo-induced disease by enhancing salicylic acid defense and interfering with the abscisic acid response to virulence.

Implementation of a Performance Evaluation Platform for Relative Navigation and Its Application to Performance Improvements (상대항법 성능 분석 플랫폼 개발 및 이를 이용한 성능 개선)

  • Choi, Heon-Ho;Shim, Woo-Seong;Cho, Sung-Lyong;Han, Young-Hoon;Park, Chan-Sik;Lee, Sang-Jeong
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.5
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    • pp.426-432
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    • 2012
  • The positions of vessels in JTIDS where each vessel broadcasts its position, can be found using the relative navigation method. Besides positioning, the relative navigation could be adopted for identification friend or foe, tracking targets, monitoring battle field and etc. In this paper, we have explained the fundamental operation and technical structure for the relative navigation and implemented the simulation platform to evaluate the basic function and performance of the system in arbitrary environment. Using platform, the availability of relative navigation within the group network and the characteristic of the algorithm for position prediction was verified. Based on the simulation result, it was verified that EKF based navigation algorithm could produce great initial error and need quite convergence time. To improve the performance, we proposed a new navigation algorithm which uses the minimum norm estimation algorithm until the EKF converges. The simulation results reveal the relative navigation can be effectively used in the formation flight and collision avoidance system.

Chemical Reactivity of Ti+ within Water, Dimethyl Ether, and Methanol Clusters

  • Koo, Young-Mi;An, Hyung-Joon;Yoo, Seoung-Kyo;Jung, Kwang-Woo
    • Bulletin of the Korean Chemical Society
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    • v.24 no.2
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    • pp.197-204
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    • 2003
  • The intracluster ion-molecule reactions of $Ti^+(H_2O)_n,\;Ti^+(CH_3OCH_3)_n,\;and\;Ti^+(CH_3OD)_n$ complexes produced by the mixing of the laser-vaporized plasma and the pulsed supersonic beam were studied using a reflectron time-of-flight mass spectrometer. The reactions of $Ti^+$ with water clusters were dominated by the dehydrogenation reaction, which produces $TiO^+(H_2O)_n$ clusters. The mass spectra resulting from the reactions of $Ti^+\;with\;CH_3OCH_3$ clusters exhibit a major sequence of $Ti^+(OCH_3)_m(CH_3OCH_3)_n$ cluster ions, which is attributed to the insertion of $Ti^+$ ion into C-O bond of $CH_3OCH_3$ followed by $CH_3$ elimination. The prevalence of $Ti^+(OCH_3)_m(CH_3OD)_n$ ions in the reaction of $Ti^+\;with\;CH_3OD$ clusters suggests that D elimination via O-D bond insertion is the preferred decomposition pathway. In addition, the results indicate that consecutive insertion reactions by the $Ti^+$ ion occur for up to three precursor molecules. Thus, examination of $Ti^+$ insertion into three different molecules establishes the reactivity order: O-H > C-O > C-H. The experiments additionally show that the chemical reactivity of heterocluster ions is greatly influenced by cluster size and argon stagnation pressure. The reaction energetics and formation mechanisms of the observed heterocluster ions are also discussed.

Solubility Enhancement of Flavonols in the Inclusion Complex with Thioether-bridged Dimeric β-Cyclodextrins

  • Cho, Eunae;Jeong, Daham;Paik, Hyun-Dong;Jung, Seunho
    • Bulletin of the Korean Chemical Society
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    • v.35 no.8
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    • pp.2487-2493
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    • 2014
  • Dimeric ${\beta}$-cyclodextrin linked by a thioether bridge was synthesized from a reaction of mono-6-iodo-6-deoxy-${\beta}$-cyclodextrin with sodium sulfide, and the structure was analyzed using nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The effects of thioether-bridged dimeric ${\beta}$-CD on the aqueous solubility of flavonols (myricetin, quercetin, and kaempferol) were investigated by ultraviolet-visible spectroscopy. The aqueous solubility of myricetin, quercetin, and kaempferol were enhanced 33.6-, 12.4-, and 10.5-fold following the addition of 9 mM of thioether-bridged dimeric ${\beta}$-CD. In comparison, the aqueous solubility of myricetin, quercetin, and kaempferol were enhanced 5.4-, 3.3-, and 2.7-fold using the same concentration of monomeric ${\beta}$-cyclodextrin. Furthermore, the formation of flavonol/thioether-bridged dimeric ${\beta}$-CD inclusion complexes was confirmed with nuclear magnetic resonance, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. The results showed that the nature of the complexes significantly differed from that of free flavonols. Herein, we suggest that the thioether-bridged dimeric ${\beta}$-CD can act as an effective complexing agent for flavonols.