• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.37-44
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• 2003

We examined the effect of polyether-type nonionic surfactants (Brij 35, Triton X-100, Tween 20 and Tween 80) on the potentiometric properties of sodium-, potassium- and calcium-selective membranes which are prepared with widely used ionophores and four kinds of polymer matrices [poly(vinyl chloride) (PVC), polyurethane (PU), PVC/PU blend, and silicone rubber (SR)]. It was found that the PVC-based membranes, which provide the best performance among all other matrix-based membranes in the absence of nonionic surfactants, exhibited larger change in their potentiometric properties when nonionic surfactants are added to the sample solution. On the other hand, the sodium-selective SR-based membrane with calix[4]arene, potassium-selective PVC/PU- or SR-based membrane with valinomycin, and the calcium-selective SR-based membrane with ETH 1001 provide almost identical analytical performance in the presence and absence of Tween 20 or Tween 80 surfactants. The origin of nonionic surfactants effect was also investigated by interpreting the experimental results obtained with various matrices and ionophores. The results suggest that the nonionic surfactant extracted into the membrane phase unselectively form complexes with the primary and interfering ions, resulting in increased background potential and lower binding ability for the ionophore. Such effects should result in deteriorated detection limits, reduced response slopes and lower selectivity for the primary ions.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1465-1470
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• 2004

A short and efficient synthesis, solvent extraction and potentiometric measurements of new thiazole-containing naphtho-crown ethers are reported. The naphthalene moiety enhances the ammonium ion selectivity over potassium ion. The selectivity of ${NH_4}^+/K^+$ follows the trend $3\;{\approx}\;2\;>\;1$, indicating that the differences in conformational changes of 2 and 3 in forming ammonium complexes affect little on the resulting ammonium/potassium extraction selectivity ratio. The ammonium ion-selective electrodes were prepared with noctylphenyl ether plasticized poly(vinyl chloride) membranes containing 1-4 the effect of one naphthalene unit introduced on either right (2) or left (3) side of thiazolo-crown ether on their potentiometric properties (e.g., ammonium ion selectivity over other cations, response slopes, and detection limits) were not apparent. However, the ammonium ion selectivity of 1, 2 and 3 over other alkali metal and alkaline earth metal cations is 10-100 times higher than that of nonactin.

• Korean Chemical Engineering Research
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• 제49권3호
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• pp.348-351
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• 2011

본 연구에서는 폴리다이아세틸렌(polydiacetylene, PDA) 베시클을 이용하여 여러 가지 킬레이트제(chelating agent)를 쉽게 검출할 수 있는 센서 시스템을 개발하였다. 다른 센서들과 비교하여 PDA기반 센서는 많은 장점이 있다. 첫째로, 형광물질의 부착이 필요 없는 무표지 검출(label-free detection)이 가능하여 실험 절차가 간단하고 빠르다. 둘째로, PDA는 청색에서 외부 자극에 의해 적색으로 변화하는 색전이를 일으키므로 육안으로 쉽게 검출을 확인할 수 있었다. 끝으로, 특정 파장에서의 colorimetric response를 측정하여 각각의 킬레이트제의 농도에 따른 정량검출도 가능하다. 본 연구에서는 5가지 종류의 킬레이트제, 즉 EDTA, EGTA, NTA, DCTA, DTPA를 PDA 베시클과 반응시켰으며, 이중에서 EDTA, DCTA는 특히 강한 반응으로 PDA의 색전이를 유도함을 알 수 있었다. 본 연구를 통하여 PDA 베시클을 사용하여 어떠한 기계나 동력을 사용하지 않고 색전이를 이용하여 킬레이트를 성공적으로 검출할 수 있음을 보여주었다.

• 한국산업융합학회 논문집
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• 제26권4_1호
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• pp.545-551
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• 2023

In this paper, a robot automation methodology for chemical drum assembly in semiconductor industries are presented. Robot automation is essential to resolve safety issues in which operators are directly or indirectly exposed to chemicals or fumes in assembling dispense heads on chemical drums. However, the chemical drum assembling process involves complex and difficult tasks, such as mating male/female keycodes and fastening screws with large-diameter, which may be very difficult to be performed by a single-arm robot with a commercial rigid F/T sensor. In order to solve the problems, a method for assembling a chemical drum using dual-arm collaborative robot system, compliance F/T sensor, robot vision and gripper is presented.

• Korean Chemical Engineering Research
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• 제61권3호
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• pp.463-471
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• 2023

Nitrogen-rich carbon dots (NDots) were synthesized by using uric acid as carbon and nitrogen sources. The as-synthesized NDots showed strong dual emissions at 420 nm and 510 nm with excitation at 350 nm and 460 nm, respectively. The physicochemical analyses such as X-ray photoelectron spectroscopy, Transmission electron microscopy and Fourier transform infrared spectroscopy were used to analyze the chemical, physical and morphological structures of NDots. The as-synthesized NDots exhibited wide linear range (0-100 µM) and very low detection limit (124 nM) in Ag⁺ ion sensing. In addition, Ag⁺ saturated NDots could be used as an EDTA sensor by the EDTA induced PL recovery.

• 센서학회지
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• 제17권6호
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• pp.414-417
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• 2008

This paper describes the fabrication of a Pd/poly 3C-SiC Schottky diode and its characteristics, in which the poly 3C-SiC layer and Pd Schottky contact were deposited by using APCVD and sputter, respectively. Crystalline quality, uniformity, and preferred orientations of the Pd thin film were evaluated by SEM and XRD, respectively. Pd/poly 3C-SiC schottky diodes were fabricated and characterized by I-V and C-V measurements. Its electric current density Js and barrier height voltage were measured as $2{\times}10^{-3}A/cm^2$ and 0.58 eV, respectively. These devices were operated until about $400^{\circ}C$. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature chemical sensor applications.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.237-240
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• 2005

The demand of micro electrical mechanical system (MEMS) bio/chemical sensor is rapidly increasing. To prevent the contamination of sensing area, a filtration system is required in on-chip total analyzing MEMS bio/chemical sensor. A nano-filter was mainly applied in some application detecting submicron feature size bio/chemical products such as bacteria, fungi and so on. We suggested a simple nano-filter fabrication process based on replication process. The mother pattern was fabricated by holographic lithography and reactive ion etching process, and the replication process was carried out using polymer mold and UV-imprinting process. Finally the nano-filter is obtained after removing the replicated part of metal deposited replica. In this study, as a practical example of the suggested process, a nano-dot array was replicated to fabricate nano-filter fur bacteria sensor application.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.87-87
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• 2013

The interface between nanomaterials and biosystems is emerging as one of the broadest and most dynamic areas of science and technology, bringing together biology, chemistry, physics and many areas of engineering, biomedicine. The combination of these diverse areas of research promised to yield revolutionary advances in healthcare, medicine, and life science. For example, the creation of new and powerful nanosensors that enable direct, sensitive, and rapid analysis of biological and chemical species can advance the diagnosis and treatment of disease, discovery and screening of new drug molecules. Nanowire based sensors are emerging as a powerful and general platform for ultrasensitive and multiplex detection of biological and chemical species. Here, we present the studies about noble metal nanowire sensors that can be used for sensitive detection of a wide-range of biological and chemical species including nucleic acids, proteins, and toxic metal ions. Moreover, the optical and electrochemical applications of noble metal nanowires are introduced. Noble metal nanowires are successfully used as plasmonic antennas and nanoelectrodes, thereby provide a pathway for a single molecule sensor, in vivo neural recording, and molecular injection and detection in a single living cell.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.401-402
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• 2011

• 한국산업보건학회지
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• 제33권2호
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• pp.215-229
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• 2023

Objectives: To validate the effectiveness of a real-time chemical exposure monitoring system developed by KOSHA (Korea Occupational Safety and Health Agency), we applied the system to a workplace in the electronics industry for 153 days. Methods: The monitoring system consisted of a PID chemical sensor, a LTE communication equipment, and a web-based platform. To monitor chemical exposure, four sets of sensors were placed in two manufacturing tasks - inspection and jig cleaning - which used TCE as a degreasing agent. We reviewed previous reports of work environment measurements and conducted a new work environment measurement on one day during the period. The PID sensor systems detected the chemical exposure levels in the workplace every second and transmitted it to the platform. Daily average and maximum chemical exposure levels were also recorded. Results: We compared the results from the real-time monitoring system and the work environment measurement by traditional methods. Generally, the data from the real-time monitoring system showed a higher level because the sensors were closer to the chemical source. We found that 28% of jig cleaning task data exceeded the STEL. Peak exposure levels of sensor data were useful for understanding the characteristics of the task's chemical use. Limitations and implications were reviewed for the adoption of the system for preventing poisoning caused by chemical substances. Conclusions: We found that the real-time chemical exposure monitoring system was an efficient tool for preventing occupational diseases caused by chemical exposure, such as acute poisoning. Further research is needed to improve the reliability and applicability of the system. We also believe that forming a social consensus around the system is essential.