• 정보통신설비학회논문지
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• 제11권2호
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• pp.34-38
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• 2012

In this paper, the particle swarm optimization (PSO) algorithm is adopted to design a modified ring-slot type patch rectenna with a resonance frequency of 2.45GHz. In order to accomplish minimization of dimensions and circular polarization (CP) and harmonic suppression, axial direction slits and side-cuts are added to the patch of the ring. The PSO manipulated this kind of multi-dimensional problem very well, and as a result, the designed rectenna shows a desirable performance of return loss of 21.36dB and axial ratio of 2.92dB at the frequency of 2.45GHz with compact sizing.

• 전기학회논문지
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• 제62권11호
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• pp.1578-1583
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• 2013

In this paper, stochastic optimization algorithms of PSO (Particle Swarm Optimization) and APSO (Adaptive Particle Swam Optimization) are studied and compared. It is revealed that the APSO provides faster convergence and better search efficiency than the conventional PSO when they are adopted to find the global minimum of a two-dimensional function. The advantages of the APSO comes from the ability to control the inertia weight, and acceleration coefficients. To verify that the APSO is working better than the standard PSO, the design of a 10GHz microstrip patch as one of the elements of a high frequency array antenna is taken as a test-case and shows the optimized result with 5 iterations in the APSO and 28 iterations in th PSO.

• 한국정보통신학회논문지
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• 제17권8호
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• pp.1796-1803
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• 2013

본 논문에서는 IE3D를 기반으로 하는 새로운 PSO(Particle Swarm Optimization) 알고리즘을 사용해 이동통신용마이크로스트립 패치 안테나를 설계하였다. 본 논문의 목적은 이동통신용 급전 사각형 마이크로스트립 안테나를 설계하고, 대역폭의 복사 매개변수에 대한 안테나 크기(길이, 폭) 및 기판 매개변수 상대 유전 상수(${\varepsilon}r$), 기판 두께의 영향을 연구하여 이동통신용에 적합한 안테나를 설계하는 것이다. 안테나 설계 프로그램인 IE3D에 PSO알고리즘을 적용하여 안테나의 낮은 입력저항, 대역폭, 안테나의 이득 등을 개선하였다.

• 청정기술
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• 제24권2호
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• pp.105-111
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• 2018

본 연구는 입자 내에서 패치의 위치를 정교하게 제어할 수 있는 새로운 친환경 공정기술에 관한 것이다. 물리화학적으로 안정한 소재를 활용한 미세성형 기술과 패치의 위치를 제어할 수 있는 선택적 제거방법을 결합하여 수행하였다. 미세성형 기술에는 이방성 구조의 패치입자의 형상을 안정적으로 구현하기 위하여, perfluoropolyether (PFPE) 마이크로몰드를 사용하였다. 이를 통하여, 소수성의 패치소재가 poly(dimethylsiloxane) (PDMS) 마이크로몰드 내로 확산되는 문제를 극복할 수 있었다. 그리고, 이는 패치의 우수한 형상 안정성과 소수성 패치소재를 이용한 패치입자 제조를 가능하게 하였다. 마지막으로 패치의 위치가 서로 다른 12종의 패치입자를 제조하여 향상된 공정 안정성을 확인하였다. 본 연구에서 제시한 미세성형 기술과 패치의 선택적 제거방법은 패치의 위치가 선택적으로 제어된 이방성의 입자를 적은 공정의 수를 거쳐 빠르게 제조할 수 있는 장점을 가진다. 또한 제조된 패치입자는 방향성이 유도된 자기조립 분야, 조절이 가능한 약물 전달 시스템 등의 다양한 연구에 널리 활용될 수 있으리라 기대한다.

• 생물환경조절학회지
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• 제21권2호
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• pp.140-146
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• 2012

나노 크기인 5nm 이하로 제조한 은나노제품(파이투패치)은 주요 식물병원균인 탄저병원균(Collectotrichum gloeosporioides), 잿빛곰팡이병원균(Botrytis cinerea), 균핵병원균(Sclerotinia sclerotiorum)에 대해 포자발아 및 균사생장을 억제하는 항균력이 있었다. 파이투패치 살포에 의한 고추탄저병 방제효과를 실험하기 위해 파이투패치 희석액에 포자를 침지하여 포습시킨 후 발아율을 조사한 결과 5ppm까지 희석한 처리구에서 병원균의 포자발아억제효과를 보였으며, 균사는 10ppm에서 생장억제효과가 15일간 지속되었다. 특히 파이투패치를 10ppm으로 희석하여 배지표면에 도말한 후 탄저병원균 포자를 접종하면 3일간 발아가 억제되어 식물체 감염을 효과적으로 예방하였으며, 40% 이상 발병한 시험구에 4ppm 파이투패치를 살포한 결과 21일 후 7% 이하의 발병과율로 무처리 대비 70% 방제효과가 있었다. 장마철 탄저병 발생율이 94.6%인 시험포장에서 10ppm 농도로 파이투패치를 7일간격으로 엽면살포한 결과 발병과 발생율이 5.8%로 방제효과를 확인하였으며, 수확한 홍고추를 자연건조한 후에도 발병과율이 24.2%로 건고추 수확량도 증가하였다. 장마철 고추역병(Phytophthora capsici)은 장마가 끝난 무피복시험구에서 8월 11일 15%이었으며 고온기를 지난 9월 7일에는 발병율이 74%로 수확을 포기하였으나, 파이투패치를 코팅처리한 피복재를 씌운 시험구에서는 발병주가 2.3%로 장마철 역병발생이 효과적으로 방제되었다.

• 전기전자학회논문지
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• 제22권3호
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• pp.793-799
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• 2018

An improved design of Ultra Wide Band(UWB) Bow-Tie antenna, which can control an enhanced wide stop-band, is presented. The mutually coupled slot-pair improves and controls the rejection band. The UWB antenna is composed of an electromagnetically coupled Bow-Tie patch and a parasitic ground patch, whose working frequency is extended to full UWB range in this work. By adding slot-pairs on the main patch and optimizing, they can give any requested wide rejection bands and sharp skirt characteristics, as is often required for UWB antennas and multi-band antennas. All the parameters are precisely calculated by an adequate optimization method. The Particle Swarm Optimization(PSO) technique is appropriately adopted. The proposed design and method is proved to give and control the sharp-skirt wide stop-band to UWB Bow-Tie antennas.

• Journal of Pharmaceutical Investigation
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• 제31권4호
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• pp.241-256
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• 2001

Alginate microspheres, containing fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) or green fluorescent protein (GFP) were prepared and used as a model drug to develop the oral vaccine delivery system. The alginate microspheres were coated with poly-L-lysine or chitosan. Two methods, w/o-emulsion and spray, were used to prepare alginate microspheres. To optimize preparation conditions, effects of several factors on the particle size and particle morphology of microsphere, and loading efficiency of model antigen were investigated. In both preparation methods, the particle size and the loading efficiency were enhanced when the concentration of sodium alginate increased. In the w/o-emulsion preparation method, as the concentration of Span 80 was increased from 0.5% to 2%, the particle size was decreased, but the loading efficiency was increased. The higher the emulsification speed was, the smaller the particle size and loading efficiency were. The concentration of calcium chloride did not show any effect on the particle size and loading efficiency. In the spray preparation method, the particle size was increased as the nozzle pressure $(from\;1\;kgf/m^2\;to\;3\;kgf/m^2)$ and spray rate was raised. Increasing calcium chloride concentration (<7%) decreased the particle size, in contrast to no effect of calcium chloride concentration on the w/o-emulsion preparation method. Alginate microspheres prepared by two methods were different in the particle size and loading efficiency, the particle size of microspheres prepared by the spray method was about $2-6\;{\mu}m$, larger than that prepared by the w/o emulsion method $(about\;2{\mu}m)$, and the loading efficiency was also higher with spray method. Furthermore, drying process for the microspheres prepared by the spray was simpler and easier, compared with the w/o emulsion preparation. Therefore, the spray method was chosen to prepare alginate microspheres for further experiments. Release pattern of FITC-BSA in alginate microspheres was evaluated in simulated intestinal fluid and PBS (phosphate buffered saline). Dissolution rate of FITC-BSA from alginate/chitosan microsphere was lower than that from alginate microsphere and alginate/poly-L-lysine microsphere. By confocal laser scanning microscope, it was revealed that alginate/FITC-poly-L-lysine microspheres were present in close apposition epithelium of the Peyer's patches of rabbits following inoculation into lumen of intestine, which proved that microspheres could be taken up by Peyer's patch. In conclusion, it is suggested that alginate microsphere prepared by spray method, showing a particle size of & $10\;{\mu}m$ and a high loading efficiency, can be used as a model drug for the development of oral vaccine delivery system.

• Journal of Pharmaceutical Investigation
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• 제29권4호
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• pp.315-321
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• 1999

Poly (lactide-co-glycolide) (PLGA) microspheres containing ovalbumin (OVA) as a model protein drug were prepared by double emulsification method, and various conditions such as mixing rate, volume of outer phase and isopropyl alcohol concentration in outer phase during secondary emulsification were observed to control the size of microspheres. In addition, entrapment efficiency of OVA and protein denaturation were also evaluated. As the rate of stirring was increased, the size of particles was decreased. But excessive stirring increased the particle size of microspheres. In a preparation condition of small volume of outer phase, the particle size was decreased but the entrapment efficiency was increased. Adding isopropyl alcohol to outer phase decreased the size of particles, but increased the entrapment efficiency. Microparticles should have smaller size than $10\;{\mu}m$ to be uptaked by Peyer's patch in small intestine. High speed of mixing and relatively small volume of outer phase are needed to reduce the size. In addition, appropriate amount of isopropyl alcohol in outer phase also plays an important role in size reduction of PLGA microspheres.

• ALGAE
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• 제34권4호
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• pp.315-326
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• 2019

Northeastward drifts of massive Sargassum patches were observed in the East China Sea (ECS) and Yellow Sea (YS) by the Geostationary Ocean Color Imager (GOCI) in May 2017. Coverage of the brown macroalgae patches was the largest ever recorded in the ECS and YS. Three-dimensional circulation modeling and Lagrangian particle tracking simulations were conducted to reproduce drifting trajectories of the macroalgae patches. The trajectories of the macroalgae patches were controlled by winds as well as surface currents. A windage (leeway) factor of 1% was chosen based on sensitivity simulations. Southerly winds in May 2017 contributed to farther northward intrusion of the brown macroalgae into the YS. Although satellite observation and numerical modeling have their own limitations and associated uncertainties, the two methods can be combined to find the best estimate of Sargassum patch trajectories. When satellites were unable to capture all patches because of clouds and sea fog in the ECS and YS, the Lagrangian particle tracking model helped to track and restore the missing patches in satellite images. This study suggests that satellite monitoring and numerical modeling are complementary to ensure accurate tracking of macroalgae patches in the ECS and YS.

• Applied Biological Chemistry
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• 제48권4호
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• pp.404-410
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• 2005

Sopoongsan is an oriental medicinal composition including 12 medicinal herbs. Sopoongsan is known to have anti-inflammatory, antimicrobial, anti-allergic, and anticancer effects on human skin. The results of stability test showed that the creams containing Sopoongsan extracts were very stable at both accelerated temperature conditions and sun-light. And pH and viscosity of each cream did not change greatly for 56 days. From the particle size and rheological measurements, it can be known that when the amount of the Sopoongsan extracts increases, the mean value of particle size decreases, and the value of the complex modulus and loss angle increases, which means the Sopoongsan extracts help stabilize the emulsion. From the result of human patch test to assess the safety of cream containing Sopoongsan extracts, there was no stimulus of negative reaction on skin. In result of the user tests, it can be known that the higher concentration of the Sopoongsan was preferred by customers.