• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2021년도 제64차 하계학술대회논문집 29권2호
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• pp.489-490
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• 2021

본 연구에서는 해양사고 처리 중 발생하는 인명사고 발생률을 감소시키고, 효율적으로 양식장을 관리하는 것을 전제로 카메라와 센서를 다기능 해양탐사 로봇에 적용하고자 한다. 현재의 양식장 관리 시스템은 수온 체크만 할 수 있게 되어있다. 이러한 시스템은 양식어에게 적합한 환경을 제공해주기 쉽지 않다. 본 논문은 이러한 문제점들을 개선하기 위해 기존의 해양 처리시스템과 양식 시스템 대신 카메라와 수온 센서, pH 농도 센서, 초음파 거리 센서, DC 모터, 블루투스 모듈을 적용한 다기능 해양탐사 로봇 기술을 제안한다. 기존의 시스템과는 다르게 안전하고 효율적으로 환경을 분석하고, 제어할 수 있다.

• 센서학회지
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• 제30권5호
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• pp.326-330
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• 2021

Reactions between gold (Au) surface plasmon resonance (SPR) chips and bovine serum albumin (BSA) dissolved in solutions of different pH were investigated. The charge on the BSA depends on the pH of the solution in which it is dissolved. Thus, dissolving BSA in different pH solutions resulted in different charges of BSA. Among the BSA dissolved in solutions with pH 4.01, 7.4, and 10.01, the SPR response was the highest for BSA dissolved in the solution of pH 4.01. To eliminate the response variation owing to the difference in the refractive indices of the solutions, phosphate buffered saline (PBS) was injected into the system after the reaction of BSA with the Au SPR chip had happened. In this case too, the BSA dissolved in the solution with pH 4.01 exhibited the highest response. This may be attributed to the non-uniform distribution of ionic patches on the BSA, which can induce electrostatic attraction to the surface even though BSA has a positive charge at pH 4.01, and the absolute values of the net charge of BSA at pH 4.01 and 7.4 were very close.

• 센서학회지
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• 제18권5호
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• pp.365-371
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• 2009

In this study, we have fabricated a fiber-optic pH sensor which is composed of a light source, plastic optical fibers and a spectrometer. As an indicator, a phenol red is used, and a pH liquid solution is prepared by mixing of phenol red and various kinds of pH buffer solutions in these experiments. The emitting light from a light source is guided by plastic optical fibers to the pH liquid solution, and the optical characteristic of a light is changed in the pH liquid solution according to its color change. Therefore, we have measured the intensities and wavelength shifts of the modulated lights, which are changed due to the color variations of phenol red at different pH values, by using of a spectrometer for spectral analysis. Also, the relationships between the pH values of liquid solutions and the optical properties of modulated light according to the change of color of phenol red are obtained.

• 대한화학회지
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• 제48권6호
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• pp.654-658
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• 2004

• 센서학회지
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• 제21권4호
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• pp.256-262
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• 2012

Hyaluronic acid(HA) hydrogels were synthesized by immersing HA microbeads in phosphate buffered saline solutions having different pH levels to assess the effect of pH on the swelling ratio of HA hydrogels for smart drug delivery systems. No beads were formed when the HA solution(below pH 9) was crosslinked with divinyl sulfone(DVS) because DVS is a basic solution. The variation regarding the size of the microbead was not significant, suggesting that the bead size is not a function of pH(10 ~ 14). However, the pore size of the microbeads decreased with increasing pH from 10 to 14, leading to the surface smoothness and dense network as a result of higher crosslinking. The swelling ratio of hydrogels increased when the pH rose from 2(acidic) to 6(neutral). Afterwards, it decreased with further increasing pH(basic). The lower swelling ratio may be due to the lack of ionization of the carboxyl groups. On the other hand, a higher swelling ratio is likely due to the increased electrostatic repulsions between negatively charged carboxyl groups on different chains. Experimental results suggested that pH-responsive HA hydrogels can be applicable to the controlled drug delivery systems.

• 대한화학회지
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• 제36권4호
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• pp.496-503
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• 1992

반도체 수소이온센서인 pH-ISFET를 제조 하고, 이를 ISFET 요소 센서로 이용하기 위하여 pH-ISFET의 Si$_3$$N_4$ 막 위에 요소 분해효소인 urease를 감광성 고분자 물질인 PVA-SbQ를 이용하여 고정화하였다. 제조된 센서는 빠른 응답특성과 우수한 재현성을 보였으며, 약 1∼50 mg/dl의 요소농도를 정량할 수 있었다. 또한 그 임상적용을 위한 기초연구로서 혈액 중에 존재하는 여러 가지 물질들이 센서의 출력에 미치는 영향을 조사하였으며, 혈장의 요소농도를 측정하여 현재 실용되고 있는 분광광도법의 결과와 비교하였다.

• 센서학회지
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• 제21권3호
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• pp.186-191
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• 2012

In this paper, we present a pH measurement method that uses a microcantilever-array-based biosensor system. It is composed of microcantilever array, liquid cell, micro syringe pump, laser diode array, position sensitive detector, data acquisition device, and data processing software. Four microcantilevers are functionalized with pH-sensitive MHA(mercaptohexadecanoic acid) as a probe, while three microcantilevers are functionalized with HDT(hexadecane thiol) as reference. We prepare PBS(phosphate buffered saline) solutions of different pH and inject them into the liquid cell with a predefined volumetric speed at regular time intervals. The functionalized mircocantilevers in the liquid cell deflect as a self-assembled monolayer on the microcantilever binds with probe molecules in the solution. The difference in deflection between the MHA-covered probe microcantilever and the HDT-covered reference microcantilever was used to compensate for thermal drift. The deflection difference clearly increases with increasing pH in the solution. It was shown that when the pH values of the PBS solutions are high, there were large variations in the deflection of microcantilevers, whereas there were small variations for low pH value. The experimental results show that the microcantilever array functionalized with MHA and HDT can detect pH value with good repeatability.

• 센서학회지
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• 제9권2호
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• pp.106-112
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• 2000

REFET(reference electrode field-effect transistor)의 사용은 기준전각의 집적화 및 FET형 전해질 센서가 가지고 있는 온도와 빛의 의존성, 드리프트와 같은 전형적인 문제점들을 해결할 수 있는 효과적인 방법이다. 그러나 언급한 문제를 해결하기 위한 신뢰성 높은 REFET의 제작은 매우 어렵고 까다롭다. 본 논문에서는 고분자 이중층을 이용한 이온 방해막을 형성하여 고신뢰성의 REFET를 제작하여 FET형 전해질 센서에 적용하였다. 제작된 REFET를 pH, pNa-ISFET에 적용하여 측정한 결과, 정상적인 감도(55.4mV/pH, 53.5mV/decade)와 안정도를 보였으며, 드리프트 감소도 향상되었다.

• 센서학회지
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• 제5권2호
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• pp.15-20
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• 1996

감지막 내부로의 수소이온 확산은 pH-ISFET에서 드리프트로 작용하므로 초박막화된 감지막은 드리프트 시간을 최소화할 것이라는 새로운 인식을 가지고 pH-ISFET의 최대 단점인 드리프트 특성을 개선하기 위하여 sol-gel법으로 $Ta_{2}O_{5}$ 수소이온 감지막을 약 $70{\AA}$정도로 초박막화시킨 ISFET를 제조하고 그 동작특성을 조사하였다. 제조한 $Ta_{2}O_{5}$ 게이트 pH-ISFET는 약 59 mV/pH의 높은 감도를 나타내었고, pH $3{\sim}11$ 범위에서 pH에 따른 ISFET의 출력전압변화는 우수한 선형성을 나타내었으며, 또한 출력전압의 변동에 의한 평균 pH 드리프트는 약 0.06 pH/day로서 비교적 작은 값을 나타내었다.

• 센서학회지
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• 제21권3호
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• pp.223-228
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• 2012

In this study, a fiber-optic pH sensor based on a pH sol-gel film is fabricated. The sol-gel film is made by co-polymerizing tetramethoxysilane, trimethoxymethylsilane, ethanol and distilled water. As a pH indicator, a neutral red is immobilized in a thin porous film formed by the sol-gel process. The pH change in a sensing probe gives rise to a change in the color of the pH sol-gel film, and the absorbance of reflected light through the pH sol-gel film is also changed. By using a spectrometer, therefore, the spectra of reflected lights in the sensing probe with different pH values are measured. Also, the relationships between the pH values and the absorbance are analyzed on the basis of the color variations of the pH sol-gel films. In repeated experiments, the fiber-optic pH sensor shows that it has reversibility, a high reproducibility and a wide absorbance change in a pH range from pH 5 to 9. Also, we confirmed that the fabricated pH sol-gel film exhibits a fast response time, little or no pH indicator leaching and a dynamic range of 2.04 dB from pH 5 to 9. Based on the results of this study, a fiber-optic pH sensor can be developed for the pH monitoring in the harsh environments.