• Title/Summary/Keyword: open circuit

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Development of a Portable and Disposable pH Sensor Based on Titanium Wire with High Electrochemical Sensing Performance (우수한 전기화학적 센싱 성능을 지닌 티타늄 와이어 기반의 휴대 및 일회용 pH 센서 개발)

  • Yoon, Eun Seop;Yoon, Jo Hee;Son, Seon Gyu;Kim, Seo Jin;Choi, Bong Gill
    • Applied Chemistry for Engineering
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    • v.32 no.6
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    • pp.700-705
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    • 2021
  • A portable and disposable pH sensor based on Ti wire was successfully developed for monitoring hydronium ion concentrations. A sensing electrode was prepared by electrochemically depositing iridium oxide onto a Ti wire, while a reference electrode was fabricated by coating Ag/AgCl ink on a Ti wire. Combining the two electrodes in the pH sensor enabled the collection of open circuit potential signals when the sensor was immersed in solutions of various pH values. The pH sensor exhibited excellent electrochemical sensing performance in terms of sensitivity, response time, repeatability, selectivity, and stability. To demonstrate point-of-measurement applications, the pH sensor was integrated with a wireless electronic module that could communicate with a mobile application. The portable pH sensor accurately measured pH changes in real samples. The results obtained were consistent with those of using a commercial pH meter.

Electrochemical Behavior of Sm(III) on the Aluminium-Gallium Alloy Electrode in LiCl-KCl Eutectic

  • Ye, Chang-Mei;Jiang, Shi-Lin;Liu, Ya-Lan;Xu, Kai;Yang, Shao-Hua;Chang, Ke-Ke;Ren, Hao;Chai, Zhi-Fang;Shi, Wei-Qun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.2
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    • pp.161-176
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    • 2021
  • In this study, the electrochemical behavior of Sm on the binary liquid Al-Ga cathode in the LiCl-KCl molten salt system is investigated. First, the co-reduction process of Sm(III)-Al(III), Sm(III)-Ga(III), and Sm(III)-Ga(III)-Al(III) on the W electrode (inert) were studied using cyclic voltammetry (CV), square-wave voltammetry (SWV) and open circuit potential (OCP) methods, respectively. It was identified that Sm(III) can be co-reduced with Al(III) or Ga(III) to form AlzSmy or GaxSmy intermetallic compounds. Subsequently, the under-potential deposition of Sm(III) at the Al, Ga, and Al-Ga active cathode was performed to confirm the formation of Sm-based intermetallic compounds. The X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analyses indicated that Ga3Sm and Ga6Sm intermetallic compounds were formed on the Mo grid electrode (inert) during the potentiostatic electrolysis in LiCl-KCl-SmCl3-AlCl3-GaCl3 melt, while only Ga6Sm intermetallic compound was generated on the Al-Ga alloy electrode during the galvanostatic electrolysis in LiCl-KCl-SmCl3 melt. The electrolysis results revealed that the interaction between Sm and Ga was predominant in the Al-Ga alloy electrode, with Al only acting as an additive to lower the melting point.

A Study on the Stabilization of a System for Big Data Transmission of Intelligent Ventilation Window based on Sensor and MCU (센서 및 MCU기반 지능형 환기창 빅데이터전송용 시스템 안정화에 관한 연구)

  • Ryoo, Hee-Soo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.3
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    • pp.551-558
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    • 2021
  • In this paper, we made the integrated intelligent air ventilation of the actuator module that can be remotely controlled based on IoT and sensors. we implemented a ventilation window system by configuring an algorithm design and a driving circuit to control the operation of the actuator to open and close the ventilation port based on a predetermined number of data that detects indoor gas/CO2/humidity temperature and outdoor fine dust related indoor/outdoor environment. It is difficult to store, manage, and analyze data due to the large number of sensors and conditions for the transmission data of indoor air circulation module. The remote monitoring and remote wireless control screens were constructed to automate the separation and operation conditions by extracting and managing the state. We apply MQTT to enhance big data transmission and construct the system using Rocket MQ to ensure safe transmission of operational big data against system errors.

A Study on the Characteristics of TiO2-Nb2O5 Semiconductor Oxides Using Dye-Sensitized Solar Cell (TiO2-Nb2O5 반도체 산화물을 이용한 염료 감응 태양전지 특성개선연구)

  • Kim, Haemaro;Lee, Don-Kyu
    • Journal of IKEEE
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    • v.23 no.2
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    • pp.538-542
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    • 2019
  • Semiconductor oxides such as $TiO_2$ involved in light conversion efficiency are the main elements of dye-sensitized solar cells (DSSC) and are used to mix different semiconductor oxides to improve efficiency. In this research, characteristics of the dye-sensitive solar cell are studied using semiconductor oxide formed by mixing $TiO_2$ and $Nb_2O_5$. A solar cell is manufactured by adding $Nb_2O_5$ at different ratios in order to analyze electrical characteristics of a mixed semiconductor oxide on light conversion efficiency. With the addition of $Nb_2O_5$, the conductivity was further enhanced than the recombination phenomenon caused by contact with electrolytes, confirming the improve of short-circuit, open voltage, and conversion efficiency of solar cells.

Flexible Dye-sensitized Solar Cell Using Titanium Gel at Low Temperature (저온 티타늄 겔을 이용한 플렉시블 염료감응형 태양전지)

  • Ji, Seung Hwan;Park, Hyunsu;Kim, Doyeon;Han, Do Hyung;Yun, Hye Won;Kim, Woo-Byoung
    • Korean Journal of Materials Research
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    • v.29 no.3
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    • pp.183-188
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    • 2019
  • Flexible dye-sensitized solar cells using binder free $TiO_2$ paste for low temperature sintering are developed. In this paste a small amount of titanium gel is added to a paste of $TiO_2$ nanoparticle. Analysis of titanium gel paste prepared at $150^{\circ}C$ shows that it has a pure anatase phase in XRD and mesoporous structure in SEM. The formation of the titanium gel 1-2 nm coated layer is confirmed by comparing the TEM image analysis of the titanium gel paste and the pristine paste. This coating layer improves the excited electron transfer and electrical contact between particles. The J-V curves of the organic binder DSSCs fabricated at $150^{\circ}C$ shows a current density of $0.12mA/cm^2$ and an open-circuit voltage of 0.47 V, while the titanium gel DSSCs improves electrical characteristics to $5.04mA/cm^2$ and 0.74 V. As a result, the photoelectric conversion efficiency of the organic binder DSSC prepared at low temperature is as low as 0.02 %, but the titanium gel paste DSSCs has a measured effciency of 2.76 %.

Prediction of methane emission from sheep based on data measured in vivo from open-circuit respiratory studies

  • Ma, Tao;Deng, Kaidong;Diao, Qiyu
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.9
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    • pp.1389-1396
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    • 2019
  • Objective: The current study analysed the relationships between methane ($CH_4$) output from animal and dietary factors. Methods: The dataset was obtained from 159 Dorper${\times}$thin-tailed Han lambs from our seven studies, and $CH_4$ production and energy metabolism data were measured in vivo by an opencircuit respiratory method. All lambs were confined indoors and fed pelleted diet during the whole experimental period in all studies. Data from two-thirds of lambs were used to develop linear and multiple regressions to describe the relationship between $CH_4$ emission and dietary variables, and data from the remaining one third of lambs were used to validate the established models. Results: $CH_4$ emission (g/d) was positively related to dry matter intake (DMI) and gross energy intake (GEI) (p<0.001). $CH_4$ energy/GEI was negatively related to metabolizable energy/gross energy and metabolizable energy/digestible energy (p<0.001). Using DMI to predict $CH_4$ emission (g/d) resulted in a coefficient of determination ($R^2$) of 0.80. Using GEI, digestible energy intake, and metabolizable energy intake predict $CH_4$ energy/GEI resulted in a $R^2$ of 0.92. Conclusion: the prediction equations established in the current study are useful to develop appropriate feeding and management strategies to mitigate $CH_4$ emissions from sheep.

Fabrication and Chracteristics of Cutting Cell with Various Laser Conditions (다양한 레이저 조건에 따른 컷팅셀 제작 및 특성 분석)

  • Park, Jeong Eun;Kim, Dong Sik;Choi, Won Seok;Jang, Jae Joon;Lim, Dong gun
    • Journal of the Korean Solar Energy Society
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    • v.39 no.3
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    • pp.9-17
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    • 2019
  • Laser cutting cell of solar cells can achieve high voltage and efficiency through more array than conventional 6 inch cell compared to same area. In this study, we fabricated c-Si cutting cell with various lasers and laser conditions such as power, speed, and number of times. In the case of picosecond laser, excellent surface characteristics were obtained due to small surface defects and low thermal damage at the output of 20W and the speed of 100 mm/s. However, it is not possible to fabricate a cutting cell having good characteristics due to nonuniform cutting inside the wafer when the processing for forming a cutting cell is not sufficiently performed. For nanosecond lasers, the best wafer characteristics were obtained for fabrication of excellent cutting cells at a frequency of 500 kHz and a laser speed of 100 mm/s. However, the nanosecond laser has not been processed sufficiently in the condition of a number of times. As a result, it was confirmed that the wafer thickness was cut by $63{\mu}m$ of the cell thickness of $170{\mu}m$ in the condition of five times of laser process. It was found that more than 30% of the wafer thickness had to be processed to fabricate the cutting cell. After cutting the 6-inch cell having the voltage of 0.65 V, we obtained the voltage of about 0.63 V.

A Brief Investigation on the Performance Variation and Shelf Lifetime in Polymer:Nonfullerene Solar Cells

  • Lee, Sooyong;Kim, Hwajeong;Lee, Chulyeon;Kim, Youngkyoo
    • Current Photovoltaic Research
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    • v.7 no.3
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    • pp.55-60
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    • 2019
  • Polymer:nonfullerene solar cells with an inverted-type device structure were fabricated by employing the bulk heterojunction (BHJ) active layers, which are composed of poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))] (PBDB-T) and 3,9-bis(6-methyl-2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IT-M). The BHJ layers were formed on a pre-patterned indium-tin oxide (ITO)-coated glass substrate by spin-coating using the blend solutions of PBDB-T and IT-M. The solar cell performances were investigated with respect to the cell position on the ITO-glass substrates. In addition, the short-term shelf lifetime of solar cells was tested by storing the PBDB-T:IT-M solar cells in a glovebox filled with inert gas. The results showed that the performance of solar cells was relatively higher for the cells close to the center of substrates, which was maintained even after storage for 24 h. In particular, the PCE of PBDB-T:IT-M solar cells was marginally decreased after storage for 24 h owing to the slightly reduced fill factor, even though the open circuit voltage was unchanged after 24 h.

A Study on the Characteristics of Dye-Sensitized Solar Cell Using Nb2O5 Semiconductor Oxides (Nb2O5 반도체 산화물을 이용한 염료 감응 태양전지 특성 연구)

  • Kim, Haemaro;Lee, Don-Kyu
    • Journal of IKEEE
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    • v.23 no.1
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    • pp.330-333
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    • 2019
  • Various studies on dye-sensitized solar cells, which are cheaper to manufacture and have superior stability than silicon solar cells, are continuously conducted. In this study, the properties of dye-sensitized solar cells were studied using semiconductor oxides made by mixing $TiO_2$ and $Nb_2O_5$. By adding $Nb_2O_5$ in different proportions, the solar cell was made, and the surface area and electrical characteristics of this cell were measured. As $Nb_2O_5$ was added, the contact area of dye and electrolyte increased and the short-circuit current, open voltage, fill factor and conversion efficiency of dye-sensitized solar cells were confirmed to be improved.

Heterojunction Solar Cell with Carrier Selective Contact Using MoOx Deposited by Atomic Layer Deposition (원자층 증착법으로 증착된 MoOx를 적용한 전하 선택 접합의 이종 접합 태양전지)

  • Jeong, Min Ji;Jo, Young Joon;Lee, Sun Hwa;Lee, Joon Shin;Im, Kyung Jin;Seo, Jeong Ho;Chang, Hyo Sik
    • Korean Journal of Materials Research
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    • v.29 no.5
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    • pp.322-327
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    • 2019
  • Hole carrier selective MoOx film is obtained by atomic layer deposition(ALD) using molybdenum hexacarbonyl[$Mo(CO)_6$] as precursor and ozone($O_3$) oxidant. The growth rate is about 0.036 nm/cycle at 200 g/Nm of ozone concentration and the thickness of interfacial oxide is about 2 nm. The measured band gap and work function of the MoOx film grown by ALD are 3.25 eV and 8 eV, respectively. X-ray photoelectron spectroscopy(XPS) result shows that the $Mo^{6+}$ state is dominant in the MoOx thin film. In the case of ALD-MoOx grown on Si wafer, the ozone concentration does not affect the passivation performance in the as-deposited state. But, the implied open-circuit voltage increases from $576^{\circ}C$ to $620^{\circ}C$ at 250 g/Nm after post-deposition annealing at $350^{\circ}C$ in a forming gas ambient. Instead of using a p-type amorphous silicon layer, high work function MoOx films as hole selective contact are applied for heterojunction silicon solar cells and the best efficiency yet recorded (21 %) is obtained.