• 대한의용생체공학회:의공학회지
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• 제30권6호
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• pp.461-468
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• 2009

Magnetic resonance electrical impedance tomography (MREIT) enables us to perform high-resolution conductivity imaging of an electrically conducting object. Injecting low-frequency current through a pair of surface electrodes, we measure an induced magnetic flux density using an MRI scanner and this requires a sophisticated MR phase imaging method. Applying a conductivity image reconstruction algorithm to measured magnetic flux density data subject to multiple injection currents, we can produce multi-slice cross-sectional conductivity images. When there exists a local region of fat, the well-known chemical shift phenomenon produces misalignments of pixels in MR images. This may result in artifacts in magnetic flux density image and consequently in conductivity image. In this paper, we investigate chemical shift artifact correction in MREIT based on the well-known three-point Dixon technique. The major difference is in the fact that we must focus on the phase image in MREIT. Using three Dixon data sets, we explain how to calculate a magnetic flux density image without chemical shift artifact. We test the correction method through imaging experiments of a cheese phantom and postmortem canine head. Experimental results clearly show that the method effectively eliminates artifacts related with the chemical shift phenomenon in a reconstructed conductivity image.

• 대한화장품학회지
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• 제16권1호
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• pp.47-63
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• 1990

Image analyser was used to understand the condition of skin surface and to evaluate the efficacy of cosmetic treatment. It was unsatisfactory to analyse skin surface structure although several methods using image analyser had been presented. We developed the new system composed of image analyser and Tandem Scanning Reflected Light Microscope (TSRLM) having the remarkable optical sectioning property as image input device. By using this new system, we quantitatively measured the change of skin surface, the depth and width of furrow in micron unit, resulted by cosmetic treatments. And also three dimensional image of skin was reconstructed with serial sectioned images, which were captured through TSRLM, for better understanding of the effect of cosmetic treatment. It was found that skin relief was more easily understood and the change of skin surface caused by cosmetic treatment was more accurately measured by using this system. In addition, we was also aware of the possibility of in vivo direct measurement of skin furrow without replica. It was conceivable that our system could be applicable for study of cosmetic effects further.

• Korean Chemical Engineering Research
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• 제61권2호
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• pp.247-257
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• 2023

본 연구에서는 이미지 분석 프로그램을 통해 액적 내 박테리아 세포의 개수를 측정하는 코딩-기반의 자동화된 세포 계수 방법을 제시하였다. 먼저, 형광 이미지 기반의 분석을 위하여, 형광단백질을 발현하는 균주를 담지한 액적을 형성하고 이를 광학 및 형광 현미경을 이용하여 분석 결과를 나타냈다. 액적의 관찰을 용이하게 위하여 유리 그리드에 도포하고, 촬영한 광학 이미지를 통해 분석하고자 하는 영역(Region of Interest)을 지정하였다. 동일한 위치에서 촬영한 형광 이미지에서 앞서 지정된 영역 속 특정 임계 값을 넘는 형광 신호를 계수하여 세포 수를 정량화 하였다. 또한 서로 다른 농도의 항생제를 처리한 액적 내 박테리아의 시간에 따른 세포 개수 변화의 차이를 추적하였다. 30분 간격으로 동일한 위치에서의 형광 이미지들을 동시에 분석함으로써 시간에 따른 세포 개수 변화를 도출하였고, 본 계수법의 성능을 실험적으로 검증하였다. 본 논문의 방법은 외부 분석 프로그램을 이용한 기존 방법 대비 분석 시간을 15배 가량 단축하고, 99%의 정확도를 보이는 것으로 확인되었다. 더 나아가 사용자의 연구의 방향에 맞춰 제시된 코드의 확장 수정을 통해 다양한 종류의 세포 계수 연구에 도움이 될 것으로 기대된다.

• 환경위생공학
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• 제20권3호
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• pp.17-26
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• 2005

Many researches were focused on the data which obtained from chemical bulk analysis. It is difficult to evaluate source contribution by wet type chemical bulk analysis. In this study, we have reviewed the characterization of individual particle for source identification. We analyzed by SEM/EDX methods. We have obtained average geometric particle diameter measured by optical diameter which were resulted from SEM/EDX image scan, representative physical diameter of individual particle was $3.38\;{\mu}m\;in\;A,\;3.67\;{\mu}m\;in\;B$. In the result of image analysis at each spots particles, both samples non-sphere shapes, C-rich particles. In consequence of chemical analysis of individual particle, each sampling sites some elements.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.867-870
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• 2007

In order to solve image sticking phenomena, the gas-phase and liquid-phase interfacial reactions of photosensitive polyimide can annihilate photoreactive carbon-carbon double bonds, which remain after photo-alignment process. The annihilation processes dramatically affect residual DC and photochemical reorientation of photoactive functional groups.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1135-1142
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• 2010

A series of N(2)-benzothiazolyl substituted tetrahydroindazoles has been synthesized via cyclic ${\beta}$ keto esters. Optimum reaction condition was found as acidic toluene and effect of higher acidity towards substituted hydrazines in situ was described. Synthesized compounds have been achieved as single isomer and characterized by using 1D and 2D NMR spectral reports. Antimicrobial screening was carried out for the synthesized compounds along with a series of N(2)-pyridyl tetrahydroindazoles.1 The results of the in vitro antimicrobial screening studies revealed that compounds 13, 16 against Staphylococcus aureus, 11 against Escherichia coli, 10-12, 16 against Pseudomonas aeruginosa and 12 against Klebsiella pneumoniae recorded almost two-fold better activity compared to the standard drug used.

• Bulletin of the Korean Chemical Society
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• 제28권1호
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• pp.81-84
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• 2007

Ab initio periodic Hartree-Fock calculations with the full potential and minimum basis set are applied to interpretation of scanning tunneling microscope (STM) and atomic force microscope (AFM) images on 1TVTe2. Our results show that the simulated STM image shows asymmetry while the simulated AFM image shows the circular electron densities at the bright spots without asymmetry of electron density to agree with the experimental AFM image. The bright spots of both the STM and AFM images of VTe2 are associated with the surface Te atoms, while the patterns of bright spots of STM and AFM images are different.

• 멤브레인
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• 제21권2호
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• pp.171-176
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• 2011

분리막을 이용한 수처리 공정에서 유입 수에 함유된 부유물질이나 기타 오염물질이 막 표면 또는 내부에 축적 흡착 등의 막 오염현상으로 인해 막 성능 감소와 함께 막 분리 공정에 큰 영향을 미치게 된다. 본 연구에서는 막 표면에서의 막 오염현상을 실시간으로 모니터링 할 수 있는 기술을 연구하였다. 투명한 오염물질에 의한 분리막 표면 오염을 측정하기 위해 막 표면에 360 nm 파장의 가시광선을 조사하여 이미지를 R. G. B 값으로 추출하여 막의 오염현상을 실시간으로 모니터링 하였다. 추출된 이미지 중 400~499 nm 파장영역인 B 값이 가장 강도가 강하게 나타났다. 막 오염정도의 변화를 이미지의 강도 차이로 관찰함으로써 실시간 분석이 가능함을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제22권10호
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• pp.1120-1122
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• 2001

• 한국자기공명학회논문지
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• 제4권1호
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• pp.64-73
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• 2000

There are several methods to achieve selective NMR image of differing chemical species with the three most popular methods of Dixon's, CHESS, and SECSI. A major problem common to all chemical shift imaging methods is the uniformity of the static magnetic field and distortions introduced when RF coils are loaded with a conducting specimen. Without magnetic field shimming, these methods cannot be used to acquire selectively image protons in fat and water which are separated by approximately 3.0ppm. Experiments with a phantom, with linewidths of 2.5 to 3.5ppm, were quantitatively evaluated for the three methods and a new chemical shift imaging method. In this study the new chemical shift imaging method (modified CHESS+SECSI technique) which included a selective saturation and refocusing pulse, was developed to determine the ratios of water and fat in different samples.