• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.633-638
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• 2008

The bunsen reaction, part of IS(Iodine-sulfur) cycle that one of the hydrogen production by the thermochemical water splitting, was investigated. It was observed that $H_2SO_4$ was uniformly generated and generation of $H_2SO_4$ was independent of iodine input. However, generation of HI was decreased with increasing iodine input. It was thought that HI and unreacted iodine were formed complex compound such as $HI_3$ $HI_5$ or $HI_7$. The complex compound accelerated liquid-liquid separation properties in the product. It was also revealed that reaction kinetics was increased with increasing iodine input. Liquid-liquid separation properties were improved with increasing iodine input and reaction temperature. Moreover, no side reaction was occurred at all reaction conditions.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.3
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• pp.301-308
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• 2006

The present work explores the effect of carbon-supported platinum catalyst on the HI decomposition using gas adsorption analyzer, thermogravimetry, X-ray diffractometry, scanning electron microscopy, and gas chromatography. For this purpose, three types of activated carbon (C), Pt/C-1 wt.%, and Pt/C-5 wt.% were prepared. The HI gas conversion is crucially influenced by the amount of Pt on the carbon support. The more the amount of Pt was, the higher results in the HI gas conversion. For three types of catalysts, HI conversion increased with increasing the decomposition temperature but with decreasing the space velocity. The increase of HI conversion with temperature was more pronounced in activated carbon than that in Pt/C. From EDX result, it was found that the activated carbon comprised higher amount of iodine than the Pt/C after the decomposition reaction. This implies that the HI conversion is closely related to the amount of Iodine.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.1
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• pp.1-7
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• 2012

This study was performed to develop a low Pt content catalyst as a catalyst for HI decomposition in S-I process. Bimetallic catalysts added various amounts of Pt on a silica supported Ni catalyst were prepared by impregnation method. HI decomposition was carried out using a fixed bed reactor. As a result, Ni-Pt bimetallic catalyst showed enhanced catalytic activity compared with each monometallic catalyst. Deactivation of Ni-Pt catalyst was not observed while deactivation of Ni monometallic catalyst was rapidly occurred in HI decomposition. The HI conversion of Ni-Pt bimetallic catalyst was increased similar to Pt catalyst with increase of the reaction temperature over a temperature range 573K to 773K. From the TG analysis, it was shown that $NiI_2$ remained on the Ni(5.0)-Pt(0.5)/$SiO_2$ catalyst after the HI decomposition reaction was decomposed below 700K. It seems that small amount of Pt in bimetallic catalyst increase the decomposition of $NiI_2$ generated after the decomposition of HI. Consequently, it was considered that the activity of Ni-Pt bimetallic catalyst was kept during the HI decomposition reaction.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.93-93
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• 2017

고전력 펄스 전원공급장치를 이용한 마그네트론 스퍼터링(high-power impulse magnetron sputtering; HiPIMS)과 직류(direct current; DC) 전원공급장치를 이용한 마그네트론 스퍼터링(DC 스퍼터링)을 이용하여 제조한 티타늄 질화물(titanium nitride; TiN) 박막의 특성을 비교하였다. HiPIMS와 DC 스퍼터링 공정 중에 빗각증착을 적용하여 TiN 박막의 미세구조와 기계적 특성의 변화를 확인하였다. TiN 박막을 코팅하기 위한 기판으로 스테인리스 강판(SUS304)과 초경(cemented carbide; WC-10wt.%Co)을 사용하였다. 기판은 알코올과 아세톤으로 초음파 처리를 실시하여 기판 표면의 불순물을 제거하였다. 기판 청정 후 진공용기 내부의 기판홀더에 기판을 장착하고 $2.0{\times}10^{-5}torr$의 기본 압력까지 진공배기를 실시하였다. 진공 용기의 압력이 기본 압력에 도달하면 아르곤(Ar) 가스를 진공용기 내부로 ${\sim}10^{-2}torr$의 압력으로 주입하고 기판홀더에 라디오 주파수(radio frequency; rf) 전원공급장치를 이용하여 - 800 V의 전압을 인가하여 글로우 방전을 발생시켜 30 분간 기판 표면의 산화막을 제거하는 기판청정을 실시하였다. 기판청정이 완료되면 기본 압력까지 진공배기를 실시하고 Ar과 질소($N_2$)의 혼합 가스를 진공용기 내부로 ${\sim}10^{-3}torr$의 압력으로 주입하여 HiPIMS와 DC 스퍼터링으로 TiN 박막 제조를 실시하였다. 빗각의 크기는 $45^{\circ}$와 $-45^{\circ}$이었다. 제조된 TiN 박막은 주사전자 현미경, 비커스 경도 측정기 그리고 X-선 회절 분석기를 이용하여 특성을 분석하였다. HiPIMS로 제조한 TiN 박막은 기판 전압을 인가하지 않아도 색상이 노란색을 보이지만, DC 스퍼터링으로 제조한 TiN 박막은 기판 전압을 인가하지 않으면 노란색을 보이지 않고 어두운 갈색에 가까운 색을 보였다. TiN 박막의 경도는 HiPIMS로 제조한 TiN 박막이 DC 스퍼터링으로 제조한 TiN 박막보다 높았다. 이러한 TiN 박막의 특성 차이는 DC 스퍼터링과 비교하여 높은 HiPIMS의 이온화율에 의한 결과로 판단된다. 빗각을 적용한 TiN 박막은 미세구조 변화를 보였으며 이러한 미세구조 변화는 TiN 박막의 특성에 영향을 미치는 것을 확인하였다.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.582-592
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• 1990

Retention behavior of lanthanide-$\alpha$HiBA complexes was studied on the cation exchanger (LC-18 coated with $C_{20}H_{41}SO_4^-$). An equation predicting retention of lanthanides in isocratic or gradient elution with sodium ion and $\alpha$-HiBA concentration was derived from ion exchange equilibria of metal-ligand complex system, respectively. The relations between log k' and log [Na$^+$] /log [$\alpha$-HiBA) showed non-linearity in isocratic elution. In gradient elution a good linearity between log k' vs log R was obtained. The values of slopes (log k / log R) gave good agreements between calculation and experiment. Individual capacity factors ($k'_{Ln}^{3+}, k'_{LnL}^{2+}, k'{LnL2+}) and stability constant (${\beta}_1$, ${\beta}_2$, ${\beta}_3$) of lanthanide-$\alpha$HiBA complexes were calculated by the non-linear least square fittings using the retention equation. The correlation coefficients of lanthanides were shown better than 0.9996 between experiment and calculation.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.1
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• pp.13-21
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• 2016

The Sulfur-Iodine thermochemical hydrogen production process (SI process) consists of the Bunsen reaction section, the $H_2SO_4$ decomposition section, and the HI decomposition section. The $HI_x$ solution ($I_2-HI-H_2O$) could be recycled to Bunsen reaction section from the HI decomposition section in the operation of the integrated SI process. The phase separation characteristic of the Bunsen reaction using the $HI_x$ solution was similar to that of $I_2-H_2O-SO_2$ system. On the other hands, the amount of produced $H_2SO_4$ phase was small. To investigate the effects of $SO_2$ solubility on Bunsen reaction, the continuous Bunsen reaction was performed at variation of the amounts of $SO_2$ gas. Also, it was carried out to make sure of the effects of partial pressure of $SO_2$ in the condition of 3bar of $SO_2-O_2$ atmosphere. As the results, the characteristic of Bunsen reaction was improved with increasing the amounts and solubility of $SO_2$ gas. The concentration of Bunsen products was changed by reverse Bunsen reaction and evaporation of HI after 12 h.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1017-1024
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• 2017

Carbon thin films were deposited by HiPIMS(High Power Impulse Magnetron Sputtering). The properties and microstructures of carbon thin film were investigated with power, pressure, bias voltage and duty cycle. As the HiPIMS power increased, the deposition thickness increased and the surface tended to be rough. The increase in pressure also tended to make the surface rough, but the deposition thickness was not proportional to the pressure. As the bias voltage increased, the surface roughness became worse, the deposition thickness increased and then decreased from the critical bias voltage. Changes in the duty cycle have caused problems such as arcing, which is affected by the chamber structure and the size of the target. The $sp^2/sp^3$ fractions of thin films were estimated by XPS and it was confirmed that the fraction of thin films made by HiPIMS were larger than the fraction of thin films made by DC sputtering.

• Journal of the Korea Institute of Construction Safety
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• v.2 no.1
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• pp.21-27
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• 2019

Hybrid & Integrated Beam (HI-BEAM), one of the composite systems, appears to have the advantage of high rigidity of reinforced concrete structures and long span of steel structures. In addition, because HI-BEAM makes the ends of beams from reinforced concrete, it is able to construct ideal composite construction method for effectively joining with reinforced concrete columns and can produce high-quality concrete structures without completing them in the field. Existing studies on the HI-BEAM method are mostly studies on structural aspects or epidemiological characteristics, or studies on the productivity and cost analysis of different structures through case studies, and analysis of actual construction methods is based on actual construction sites. In this study, the economic feasibility of the HI-BEAM method is verified by comparing the productivity and construction costs of the RC-BEAM method (RC-BEAM) method and the HI-BEAM method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.413-415
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• 2019

In this paper, we develop IoT-HiAS(IoT-Human Interactive Advertising Service) for sharing economy. The HiAS device shooting the front of the device via a webcam and recognizes the person in real time through the SSD model using MobileNet. If the number of persons above the set threshold is recognized by counting the recognized person, the advertisement is reproduced on the idle resource through the beam projector. At the same time as the advertisement is reproduced, the captured image of the advertisement start time in the front of the device and the number of recognized persons are sends the IoT server of an oneM2M-compliant HiAS server using the IoT client. When the advertisement is finish, the webcam is shooting the front of the device and the image is sends the IoT server. We implemented the IoT-based human interactive advertising service by transmitting the received data to the advertiser and the advertising producers through the SNS(Social Network Service) agent of the HiAS server.

• ETRI Journal
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• v.13 no.2
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• pp.28-33
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• 1991

HiPi-Bus 는 여러가지 전송형태를 지원하며 이들은 데이터 전송의 관점에서 읽기 전송과 쓰기 전송으로 구분할 수 있다. 본 논문에서는 이들 읽기 전송과 쓰기 전송에 소요되는 시간을 최소화하는 방법을 제안하였는데, 이때 쓰기 전송에 소요되는 시간은 400n sec 이며, 읽기 전송에 소요되는 시간은 최소 400n sec 이다.