• Mass Spectrometry Letters
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• 제9권4호
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• pp.95-99
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• 2018

An innovative, simple, and rapid assay method based on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated for the simultaneous determination of eight statin drugs in human urine. A simple sample clean-up procedure using the "dilute and shoot" (DAS) approach enabled a fast and reliable analysis. The influence of the dilution factor was investigated to ensure detectability and reduce the matrix effect. Chromatographic separation was performed on a Phenomenex Kinetex C18 column ($50{\times}3.0mm$ i.d., $2.6{\mu}m$) using an elution gradient of mobile phase A composed of 0.1% acetic acid, and mobile phase B composed of acetonitrile, at a flow rate of 0.35 mL/min. Quantitation was performed on a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode using electrospray ionization in positive ion mode. The total chromatographic run time was 15 min. The method was validated for selectivity, sensitivity, recovery, linearity, accuracy, precision, and stability. The present method was successfully applied to the analysis of Rosuvastatin in urine samples after oral administration to healthy human subjects.

• 한국군사과학기술학회지
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• 제17권6호
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• pp.828-835
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• 2014

GC-TSQ CI technique was applied for analysis of samples for the $32^{nd}$ OPCW proficiency test. Eight chemical weapon convention(CWC) related chemicals were identified by product ion mode analysis with GC-TSQ in the samples. Choice of specific precursor ion made it possible to supply selective total ion chromatograms(TICs) of target molecule. GC-TSQ CI anaylsis technique was useful method for chemical warfare agent verification because analysis selectivity was improved by choice of mother molecule as precursor ion and gave mass spectra.

• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.759-764
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• 2015

Antimicrobial peptides (AMPs) are one of the critical components in host innate immune responses to imbalanced and invading microbial pathogens. Although the antimicrobial activity and mechanism of action have been thoroughly investigated for decades, the exact biological properties of AMPs are still elusive. Most AMPs generally exert the antimicrobial effect by targeting the microbial membrane, such as barrel stave, toroidal, and carpet mechanisms. Thus, the mode of action in model membranes and the discrimination of AMPs to discrepant lipid compositions between mammalian cells and microbial pathogens (cell selectivity) have been studied intensively. However, the latest reports suggest that not only AMPs recently isolated but also well-known membrane-disruptive AMPs play a role in intracellular killing, such as apoptosis induction. In this mini-review, we will review some representative AMPs and their antimicrobial mechanisms and provide new insights into the dual mechanism of AMPs.

• 한국세라믹학회지
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• 제23권3호
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• pp.21-26
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• 1986

In this study the system of $Pb(Mn_{1/3} Nb_{2/3})O_3-PbTiO_3-PbZrO_3$ piexoelectric ceramics was made in the radial mode disk and attenuation characteristic of the desinged ladder type filter was investigated. What is more temperature dependance of resonant frequency and variation of resonant frequency was examined by chan-ging the electrode diameter of piezoelectric resonator. (A Group : De=11mm, B Group : De=7.5mm and C Gro-up : De=5.5mm) Upon investigation it was the following. The center frequency of A, B and c filter showed up in the 200KHz, 270KHz and 380KHz respectively. As the electrode diameter decreased center frequency in creased abruptly. As the Co_2/Co1 increased attenuation characteristics and selectivity was improved. As the x=50. resonant frequ-ency invaried with variation of temperature.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.415.1-415.1
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• 2014

Carrying out first-principles calculations, we study N-doped capped carbon nanotube (CNT) electrodes applied to DNA sequencing. While we obtain for the face-on nucleobase junction configurations a conventional conductance ordering where the largest signal results from guanine according to its high highest occupied molecular orbital (HOMO) level, we extract for the edge-on counterparts a distinct conductance ordering where the low-HOMO thymine provides the largest signal. The edge-on mode is shown to operate based on a novel molecular sensing mechanism that reflects the chemical connectivity between N-doped CNT caps that can act both as electron donors and electron acceptors and DNA functional groups that include the hyperconjugated thymine methyl group[1].

• 한국전기전자재료학회논문지
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• 제16권10호
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• pp.887-891
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• 2003

In this paper, two filters with center frequency of 19.58MHz were cascaded and its bandwidth characteristics were investigated with the variations of coupling capacitance for intermediate frequency (IF) bandpass filter application. The cascaded filter showed the higher stop region, reduction of spurious response and increase of selectivity. With the increase of coupling capacitance, insertion loss was increased but spurious response reduced. The cascaded filter with coupling capacitance of 15pF showed insertion loss of 5.643dB, 3dB bandwidth of 55.089kHz and 20dB bandwidth of 83.608kHz, respectively.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2008년도 추계학술발표논문집
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• pp.264-266
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• 2008

본 논문은 유한한 유전체 격자구조의 정확한 주파수 선택 특성을 해석하고자 새로운 방법을 제시하였다. 기존의 오차, 근사화를 갖고 있는 해석방법과는 달리 유한한 구조에서 근사화가 전혀 없는 방법을 제시하였다. 유한한 격자구조의 유전체는 내부에 존재하는 필드 분포가 한정되어 있으며 구조 파라메터등에 따라 유한한 모드만이 생길 수 있어 입사되는 필드에 따른 생성 모드가 한정되어 있다. 본 논문은 이러한 방법을 이용하여 유전체 격자구조의 주파수 선택특성에 활용에 이용될 수 있을 것으로 사료된다.

• 한국통신학회논문지
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• 제9권1호
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• pp.30-38
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• 1984

本論文에서는 中心周波數를 클럭周波數에 의해 線型的으로 변화시킬 수 있고 選揮度와 最大利得은 캐패시터 array에 의해 디지틀信號로 制擧할 수 있는 프로그램 可能한 2次SC filter를 構成하였다. 또한 이 filter를 이용하여 formant音聲合成시스템을 構成하고 韓國誤子音을 合成함으로써 이 filter를 가지고 韓國語의 대부분이 吟聲을 實時間으로 合成할 수 있다는 可能性을 보였다.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.230.3-231
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• 2003

The therapeutic use of protein pharmaceuticals produced by recombinant DNA technology is increasing in recent decades. In order to investigate the quality of recombinant proteins, it is important to identify and assign the impurities produced in the process of recombination or in storage conditions. Capillary Electrophoresis is emerging technology exhibiting high sensitivity, selectivity and speed and may be most powerful tools for this application. In this study, human growth hormone (hGH) has been analyzed by various mode of capillary electrophoresis such as capillary zone electrophoresis (CZE), capillary gel electrophoresis (CGE), and capillary isoelectric focusing (cIEF) to indicate the chemically or biologically oriented variants and the degraded fragments. (omitted)

• 한국항행학회논문지
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• 제21권1호
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• pp.84-89
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• 2017

본 논문은 CRLH (composite right/left handed) 전송선로 구조의 4중 모드 공진기를 이용하여 높은 대역간 격리도를 갖는 이중-광대역 대역통과 여파기를 설계하는 방법을 제안한다. CRLH 전송선로 구조를 해석하여 4중 모드 공진기의 s-패러미터와 공진 주파수를 유도하였다. 유도된 s-패러미터를 이용하여 새로운 구조의 이중-광대역 대역통과 여파기를 설계, 제작하였다. 측정 결과는 2.8-5.52 GHz, 9.68-12.26 GHz의 이중 통과대역에서 각각 1.08 dB, 2.01 dB의 삽입손실을 갖고, 6.34-8.42 GHz의 중간대역에서 38dB의 대역 격리도를 가져 설계 결과와 잘 일치하는 특성을 보여 주었다.