• Bulletin of the Korean Chemical Society
• /
• 제31권3호
• /
• pp.630-634
• /
• 2010

The synthesis and ion binding properties of calix[4]pyrrole bearing pyrene moieties appended to one side of the calix[4]pyrrole are reported. The key feature is the presence of flexible fluorescence arms attached to the calix[4]pyrrole ring in a cis-fashion. The preliminary solution phase anion and cation binding studies revealed that the systems can be in fact as viable sensors for anionic guest.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
• /
• pp.447-453
• /
• 2004

Various structural materials have been used in construction projects using stones, connotes, and steels materials. Among of these projects, concretes may use widely because concretes have high compressive strength, and comparatively easy maintenance and management. Reinforced concrete Buildings will be deteriorated as time passed. These problems will be accelerated by propagation of cracks. In order to manage such cracks, time, efforts and expense are required. In this study, leakages of fluorescence and adhesive material were investigated using glass sensors that were embedded in a model beam and column. In addition, currents in glass pipe sensor were observed to find leakage of liquid in glass pipes. Progressive cracks were generated by fracture of glass me sensor. In this investigation, a reinforcement clothing system was wrapped for a glass pipe sensor, The glass pipe sensor that can make control and reinforce cracks simultaneously.

• 센서학회지
• /
• 제23권6호
• /
• pp.416-419
• /
• 2014

We grew a $Li_6Lu(BO_3)_3:Ce^{3+}$ single crystal as a new scintillator. And, the scintillation and thermoluminescence properties of the scintillator were determined. The emission spectrum of $Li_6Lu(BO_3)_3:Ce^{3+}$ is located in the range of 370~530 nm, peaking at 416 nm and 439 nm, due to the $5d{\rightarrow}4f$ transition of $Ce^{3+}$ ions. The fluorescence decay time of the crystal is composed two components. The fast component is 34 ns (84%) and the slow component is 125 ns (16%) of the crystal. The afterglow is caused by the electron and hole traps in the crystal lattice. We determined physical parameters of the traps in the crystal. The thermoluminescence trap are composed a trap. The determined activation energy (E) and frequency factor (s) of the TL trap are 1.05 eV and $4.4{\times}10^{10}s^{-1}$, respectively.

• 센서학회지
• /
• 제17권3호
• /
• pp.157-161
• /
• 2008

An optical sensor was developed to detect nanoparticles, turbid materials and microorganisms in water simultaneously. Three different light sources like UV-LED, NIR-LED and laser diode have been employed to develop the optical sensor based on the scattering light and fluorescence light. The sensor system has high selectivity and sensitivity, that it can be used to monitor the quality of drinking water.

• Journal of Biosystems Engineering
• /
• 제41권2호
• /
• pp.138-144
• /
• 2016

Purpose: Phosphorus is an essential element for water quality control. Excessive amounts of phosphorus causes algal bloom in water, which leads to eutrophication and a decline in water quality. It is necessary to maintain the optimum amount of phosphorus present. During the last decades, various studies have been conducted to determine phosphorus content in water. In this study, we present a comprehensive overview of colorimetric, electrochemical, fluorescence, microfluidic, and remote sensing technologies for the measurement of phosphorus in water, along with their working principles and limitations. Results: The colorimetric techniques determine the concentration of phosphorus through the use of color-generating reagents. This is specific to a single chemical species and inexpensive to use. The electrochemical techniques operate by using a reaction of the analyte of interest to generate an electrical signal that is proportional to the sample analyte concentration. They show a good linear output, good repeatability, and a high detection capacity. The fluorescence technique is a kind of spectroscopic analysis method. The particles in the sample are excited by irradiation at a specific wavelength, emitting radiation of a different wavelength. It is possible to use this for quantitative and qualitative analysis of the target analyte. The microfluidic techniques incorporate several features to control chemical reactions in a micro device of low sample volume and reagent consumption. They are cheap and rapid methods for the detection of phosphorus in water. The remote sensing technique analyzes the sample for the target analyte using an optical technique, but without direct contact. It can cover a wider area than the other techniques mentioned in this review. Conclusion: It is concluded that the sensing technologies reviewed in this study are promising for rapid detection of phosphorus in water. The measurement range and sensitivity of the sensors have been greatly improved recently.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
• /
• pp.553-556
• /
• 2004

Spatial and temporal aspects of toxic dinoflagellate Cochlodinium.p blooms and consequences of physical features in complex coastal ecosystems, off the southern Korean coast, have been investigated using data obtained from SeaWiFS and AVHRR as well as in-situ observations. Hydrographic parameters measured using CTD sensors were used to elucidate physical factors affecting the spatial distribution and abundance of Cochlodinium.p blooms. The results show spatial and temporal variations of chlorophyll-a (Chl-a) and sea surface temperature (SST) and reveal significant information about Cochlodinium.p blooms and process underlying their evolution. Satellitederived Chl-a estimates appear to be potential in explicating the evolution, movement and distribution of Cochlodinium.p blooms in the enclosed bays of the South Sea. The existence of thromohaline waters offshore provide favorable conditions for the rapid growth and subsequent southward initiation of Cochlodinium.p blooms that are influenced to flow on the offshore branch (OB) during September. It was observed that there was a significant variation in the sun-induced chlorophyll-a fluorescence signal in the remote sensing fluorescence spectra and its high-intensity was recognized during the period of exponential growth and physical transport. Satellite-derived Chl-a concentration during September 1999 ranged between $3­60mg/m^3$ inside the Jin-hae and adjacent Bays and $1-6mg/m^3$ in offshore waters, with varying Cochlodinium.p abundances 1500 to 26000 cells $ml^{-1}.$ The closely spaced CTD surveys and satellite-derived SST give a complete overview on the initiation of Cochlodinium.p blooms in hydrodynamically active regions of the offshore southern East Sea by the influence of Tsushima Warm Current (TWC).

• 센서학회지
• /
• 제6권5호
• /
• pp.356-361
• /
• 1997

광섬유 소산파 센서(fiber-optic evanescent wave sensor)를 제작하였다. 클래드층을 제거한 광섬유 코아 표면에 anti-mouse immunoglobulin G(IgG)를 결합시키고, 형광이 표지된 mouse IgG와의 반응을 직접적인 방법과 경쟁적인 방법을 통하여 측정하였다. 직접적인 방법과 경쟁적인 방법 모두 $1{\mu}g/m{\ell}$이하의 mouse IgG를 측정할 수 있는 감도를 얻을 수 있었다. Anti-mouse IgG는 단순 흡착 방법에 의하여 광섬유 코아 표면의 93.9%에 고정되었고 비특이적 결합반응을 제거하기 위하여 실시한 소혈청 알부민(bovine serum albumin : BSA)을 이용한 표면 코팅 효과는 없었다. Mouse IgG에 결합된 fluorescein의 비율이 높을수록 형광 발생량이 많았으나 관계는 직선적이지 않았다. 본 연구에서 제작된 광섬유 소산파 센서는 $1{\mu}g/m{\ell}$ 이하의 항원 항체 반응을 소산파 여기에 의한 형광량으로 측정할 수 있어 면역센서로의 응용이 가능할 것으로 판단된다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.281.2-281.2
• /
• 2013

Since heavy metal ions included in water or food resources have critical effects on human health, highly sensitive, rapid and selective analysis for heavy metal detection has been extensively explored by means of electrochemical, optical and colorimetric methods. For example, quantum dots (QDs), such as semiconductor QDs, have received enormous attention due to extraordinary optical properties including high fluorescence intensity and its narrow emission peaks, and have been utilized for heavy metal ion detection. However, the semiconductor QDs have a drawback of serious toxicity derived from cadmium, lead and other lethal elements, thereby limiting its application in the environmental screening system. On the other hand, Graphene oxide (GO) has proven its superlative properties of biocompatibility, unique photoluminescence (PL), good quenching efficiency and facile surface modification. Recently, the size of GO was controlled to a few nanometers, enhancing its optical properties to be applied for biological or chemical sensors. Interestingly, the presence of various oxygenous functional groups of GO contributes to opening the band gap of graphene, resulting in a unique PL emission pattern, and the control of the sp2 domain in the sp3 matrix of GO can tune the PL intensity as well as the PL emission wavelength. Herein, we reported a photoluminescent GO array on which heavy metal ion-specific DNA aptamers were immobilized, and sensitive and multiplex heavy metal ion detection was performed utilizing fluorescence resonance energy transfer (FRET) between the photoluminescent monolayered GO and the captured metal ion.

• 한국방사선학회논문지
• /
• 제13권3호
• /
• pp.333-338
• /
• 2019

방사선치료 분야에서는 치료의 안전성을 검증하기 위한 Quality Assurance(QA) 절차가 매우 중요하게 여겨진다. 그러나 일반적으로 이에 사용되는 선량계들의 다양한 문제점 때문에, 이를 대체하기 위한 선량계 연구가 활발히 진행되고 있다. 본 연구에서는 형광체로부터 방출된 visible light(VL)에 의한 Sensitivity 극대화를 위해, 뛰어난 형광 효율을 가지는 형광체인 $Gd_2O_2S:Tb$를 요오드화납(Lead(II) Iodide; $PbI_2$)에 다양한 weight percent(wt%)로 혼합한 Blended hybrid sensor를 제작하였다. 이후 Blended sensor 및 Pure $PbI_2$ sensor의 고에너지 방사선에 대한 반응특성을 비교 및 평가하였다. 민감도 평가결과, 3wt%는 sensor에서 타 sensor들과 40% 이상 차이나는 최댓값이 나타났으며, 이를 제외한 센서에서 wt%의 증가에 따른 점차적 민감도 감소추세를 확인하였다. 또한, 재현성 평가에서는 Pure $PbI_2$ sensor가 coefficient of variation(CV)>0.015의 큰 편차를 보인 반면, blended sensor는 모두 CV<0.015 이하의 결과를 보였다.

• 센서학회지
• /
• 제12권1호
• /
• pp.1-9
• /
• 2003

CsI에 활성제로 Li, K, Rb를 첨가하여 CsI(Li), CsI(K) 및 CsI(Rb) 단결정을 Czochralski방법으로 육성하였다. $^{137}CS$(0.662 MeV)에 대한 CsI(Li:0.2 mole%) 섬광체의 에너지 분해능은 14.5%이었고 CsI(K:0.5 mole%) 섬광체는 15.9%이었으며 CsI(Rb:1.5 mole%) 섬광체는 17.0%이였다. 이들 CsI(Li), CsI(K) 및 CsI(Rb) 섬광체의 $\gamma$선 에너지에 대한 에너지 교정곡선은 선형적 이였다. 일정비율 시간분석법(CFT :constant-fraction timing method)으로 측정한 CsI(Li:0.2 mole%), CsI(K:0.5 mole%) 및 CsI(Rb:1.5 mole%) 성광체의 시간 분해능은 각각 9.0 ns, 14.7 ns 및 9.7 ns이였다. CsI(Li:0.2 mole%), CsI(K:0.5 mole%) 및 CsI(Rb:1.5 mole%) 섬광체의 형광감쇠시간은 각각 ${\tau}_1=41.2\;ns$, ${\tau}_2=483\;ns$, ${\tau}_1=47.2\;ns$, ${\tau}_2=417\;ns$ 및 ${\tau}_1=41.3\;ns$ 및 ${\tau}_2=553\;ns$이였다. 그리고 CsI(Li:0.2 mole%), CsI(K:0.5 mole%) 및 CsI(Rb:1.5 mole%) 단결정의 인광감쇠시간은 각각 0.51 s, 0.57 s 및 0.56 s이였다.