Enhanced Selectivity for CO₂ Adsorption on Mesoporous Silica with Alkali Metal Halide Due to Electrostatic Field: A Molecular Simulation Approach

Kwon, Soonchul,Kwon, Hyuk Jae,Choi, Ji Il,Kim, Ki Chul,Seo, Jeong Gil,Park, Jung Eun,You, Su Jin,Park, Eun Duck,Jang, Seung Soon,Lee, Hyun Chul American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.37

<P>Since adsorption performances are dominantly determined by adsorbate adsorbent interactions, accurate theoretical prediction of the thermodynamic characteristics of gas adsorption is critical for designing new sorbent materials as well as understanding the sic), adsorption mechanisms. Here, through our molecular modeling approach using a newly developed quantum-mechanics-based force field, it is demonstrated that the CO2 adsorption selectivity of SBA-15 can be enhanced by incorporating crystalline potassium chloride particles. It is noted that the induced intensive electrostatic fields around potassium chloride clusters create gas-trapping sites with high selectivity for CO2 adsorption. The newly developed force field can provide a reliable theoretical tool for accurately evaluating the gas adsorption on given adsorbents, which can be utilized to identify good gas adsorbents.</P>

Influence of defective sites in Pt/C catalysts on the anode of direct methanol fuel cell and their role in CO poisoning: a first-principles study

Soonchul Kwon,Seung Geol Lee 한국탄소학회 2015 Carbon Letters Vol.16 No.3

Carbon-supported Pt catalyst systems containing defect adsorption sites on the anode of direct methanol fuel cells were investigated, to elucidate the mechanisms of H2 dissociation and carbon monoxide (CO) poisoning. Density functional theory calculations were carried out to determine the effect of defect sites located neighboring to or distant from the Pt catalyst on H2 and CO adsorption properties, based on electronic properties such as adsorption energy and electronic band gap. Interestingly, the presence of neighboring defect sites led to a reduction of H2 dissociation and CO poisoning due to atomic Pt filling the defect sites. At distant sites, H2 dissociation was active on Pt, but CO filled the defect sites to form carbon π-π bonds, thus enhancing the oxidation of the carbon surface. It should be noted that defect sites can cause CO poisoning, thereby deactivating the anode gradually.

Active Methanol Oxidation Reaction by Enhanced CO Tolerance on Bimetallic Pt/Ir Electrocatalysts Using Electronic and Bifunctional Effects

Kwon, Soonchul,Ham, Dong Jin,Kim, Taeyoon,Kwon, Yongju,Lee, Seung Geol,Cho, Min American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.46

<P>Platinum-based metal alloys have been generally developed to provide high carbon monoxide resistance in the anodes of direct methanol fuel cells. We report the potential of bimetallic platinum/iridium electrocatalysts in preserving the outstanding carbon monoxide tolerance obtained from both experimental and theoretical studies, which represents the enhanced electrochemical performance of methanol oxidation and the in-depth and stepwise investigations for reaction mechanisms, respectively. In this study, the findings highlight the dual-enhancement characteristics of low carbon monoxide adsorption energy (electronic effect) and carbon monoxide oxidative removal (bifunctional effect) compared with various electrocatalysts such as platinum, iridium, and platinum/ruthenium alloys. In addition, the reaction affinity of platinum/iridium alloys for methanol dehydrogenation is also studied in accordance with atomistic properties, such as adsorption energy and electronic band gap, to understand the electrochemical performance compared to Pt. The results obtained indicate that the platinum/iridium alloy surface played diverse roles in terms of its multifunctional behaviors for carbon monoxide tolerance, including the favorable mechanism of methanol dehydrogenation. It turns out that throughout the theoretical in-depth studies, platinum/iridium alloys are promising candidates in terms of the extension for electrocatalytic material designs that differ from Ru in direct methanol fuel cells.</P> [FIG OMISSION]</BR>

Predictive Guide for Collective CO₂ Adsorption Properties of Mg−Al Mixed Oxides

Kwon, Hyuk Jae,Kwon, Soonchul,Seo, Jeong Gil,Jung, In Sun,Son, You-Hwan,Lee, Chan Hyun,Lee, Ki Bong,Lee, Hyun Chul Wiley (John WileySons) 2017 CHEM SUS CHEM Vol.10 No.8

<P>Although solid adsorption processes offer attractive benefits, such as reduced energy demands and penalties compared with liquid absorption processes, there are still pressing needs for solid adsorbents with high adsorption capacities, thermal efficiencies, and energy-intensive regeneration in gas-treatment processes. The CO2 adsorption capacities of layered double oxides (LDOs), which are attractive solid adsorbents, have an asymmetric volcano-type correlation with their relative crystallinities. Furthermore, new collective adsorption properties (adsorption capacity, adsorptive energy and charge-transfer amount based on the adsorbent weight) are proposed based on density functional theory (DFT) calculations and measured surface areas. The correlation of these collective properties with their crystallinities is in good agreement with the experimentally measured CO2 adsorptive capacity trend, providing a predictive guide for the development of solid adsorbents for gas-adsorption processes.</P>

Bimodal Surface Modification of Graphyne for CO₂ and H₂: Density Functional Theory

Yongju Kwon,Jongyeong Kim,Byeonggug Kang,Soonchul Kwon 한국신재생에너지학회 2021 AFORE Vol.2021 No.10

제주도내 대학생들의 이어도에 대한 인식 조사

권순철(Soonchul Kwon),강병철(Byeongcheol Kang),양금희(Geumhee Yang) 제주학회 2016 濟州島硏究 Vol.45 No.-

지금까지 이어도 민요, 설화에 대한 논의는 지속적으로 이루어져왔으나 제주도민들의 이어도 인식에 대한 연구는 드물었다. 본 연구는 이어도 인식조사 필요성으로부터 연구가 진행되었다. 연구는 제주대학생들이 인식하는 이어도 일반, 이어도 문학, 이어도 영토, 이어도 정책 등을 조사하였다. 연구 결과는 다음과 같다. 첫째, 이어도 일반에서 이어도에 대해 대부분이 들어보았고, 실재한다도 생각하고 있으며 이어도 이미지는 해양과학기지, 해양분쟁지역, 이상향, 전설 속의 섬 등으로 인식하고 있었다. 둘째, 이어도 문학에서 전설, 시, 소설 등을 학교수업, TV, 도서, 인터넷 등을 통해 접했으나 매체나 교과 영향이 낮은 것으로 나타났다. 셋째, 이어도 영토에서 과학기지 위치, 해양영도 규모, 해양갈등 정보, 자원 정보 수준 등이 낮게 나타났다. 넷째, 이어도 정책에서 이어도의 지리과학적 가체에 대한 인식이 높았으며, 이어도 관련 교육시기는 초o중학교 때가 높게 나타났다. 이러한 결과로부터 이어도에 대한 인식이 새롭게 조명되었으며, 21세기 국제해양도시 제주에 대한 기초로서 해양문호유산인 이어도 문화를 제주도민들과 공유할 필요가 있다. 또한 급속히 변화되는 제주사회에 새로운 의식공동체를 형성할 수 있는 해양문화유산으로의 계승발전을 모색해야 할 것이다. So far, Ieodo folk songs, tales of the debate has been continuously carried out, the study of Ieodo recognition even if there is Jeju residents were rare. This study was a research from the need of Ieodo recognition research to have been promoted. In the study, it was investigated such as Jeju collegiate students recognizes of Ieodo general, Ieodo literature, Ieodo territory, Ieodo policies. The results were as follows. First, the research look contains almost to be even common of ieodo. they believe that Ieodo reality, Ieodo image, Marine science station, The marine areas of conflict, Utopia, the legendary they were aware of such as on the island Second, the Ieodo was to legend even in literature, the dty, such as the school of dass novels, TV, books, it was found that the influence of the media and subjects in contact via the Internet or the like is low. Third, location of Ieodo science station, Ieodo territory, Ieodo ocean territory scale, Ieodo ocean conflict information, such as resource information level is lower. Fourth, the recognition of geographical scientific value also be a Policy a high, timing of related education even higher during the elementary and middle schools. From these results, The IeocIo was recognized for even if it is new lighting, as an international marine city basis of Jeju in the 21st century, there is a need to share even if the culture of Ieodo and Jeju residents be in some marine cultural heritage. Moreover, it is necessary to seek inheritance develop marine cultural heritage which can form a new awareness community to rapidly changing Jeju society.

해외 유출 범죄피해재산의 피해자 환부 사례 연구

권순철(KWON, Soonchul) 대검찰청 2017 형사법의 신동향 Vol.0 No.55

피해자의 피해회복에 대해서는 어느 범죄이론이나 형벌이론에서도 그 필요성과 당위성을 부정하지 않는다. 다만, 국가형벌권을 통해 범죄자를 응보하고 범죄를 예방하는 형사사법절차의 주체인 국가기관이 재산범죄 피해자의 피해회복에 적극적으로 나설 것인지는 다른 차원의 문제라고 할 수 있다. 우리 현행 범죄수익은닉규제법은 원칙적으로 범죄피해재산의 몰수, 추징을 금지함으로써 간접적으로 피해자의 민사절차에 의한 피해 회복을 지원하는 입장을 취하고 있다. 이에 반하여 미국은 수사기관이 배상명령(Restitution)이나 몰수면제(Remission) 등의 절차를 통해 범죄피해재산을 피해자에게 회복해주는 절차를 인정하고 있다. 대검찰청은 최근 미국에서 민사몰수된 불법다단계 사기범죄수익 약 10억 원을 몰수면제에 의해 환수받아 피해자 691명에게 환부하였다. 본고는 아직 제도가 도입되지 않는 몰수면제에 의한 ‘범죄피해재산의 피해자 환부 제도’를 실험한 현장 보고서의 성격을 갖는다. 본고는 이론적 사색이 아닌 실무적인 경험을 통해 제도의 실체를 분명하게 보여줌으로써 ‘범죄피해재산의 피해자 환부 제도’의 도입론에 대해 보다 정확한 판단 자료를 제공하고자 한다. 또한 향후 이 제도가 도입될 경우 준비해야 할 것이 무엇인지에 대해 참고가 될 것으로 생각된다. 미국의 몰수면제 제도는 민사몰수 등에 의해 확보된 범죄피해재산을 피해자들로부터 신청을 받아 몰수를 면제하고 피해자들에게 환부하는 제도이다. 미국에서는 수사기관이 최대한의 재량을 가지고 주도권을 행사함으로써 효율성을 도모하고 있다. 피해자들에 대한 통지, 공고, 심사업무를 업무 대행자를 통해 수행하며 그 결과에 대해 피해자들의 불복을 허용하지 않는다. 우리의 경우, 이 제도의 도입이 필요하다는 주장이 제기되고는 있으나 아직 전통적인 민･형사 분리 사상으로 인해 쉽사리 받아들여지지 못하고 있다. 범죄피해재산의 피해자 환부 제도는 헌법상의 국가의 기본권보장의무 조항이나 범죄 피해자보호법의 기본 취지에 부합하는 제도이다. 민사, 형사, 보험제도 등 불법행위를 제어하는 사회 전체적인 안전망으로 불법행위 피해자를 보호하는 영역에서는 민･형사의 구분이 불분명해지고 있으므로 민･형사 분리사상은 도입을 반대하는 논리로서 설득력이 떨어진다. 또한, 수사기관이 피해자의 피해회복에 직접 개입하는 것이 사회 전체적으로 효율적이다. 수사 초기에는 은닉된 범죄피해재산을 발견하기 용이하며 선처를 바라는 범죄자의 협조를 끌어내기도 쉽다. 피해자들 역시 수사초기에는 단체를 구성하여 조직적으로 대응하기 쉽다. 이 제도 하에서 범죄자의 처벌과 피해회복이 매우 최적화 될 수 있는 것이다. 다만, 민사사건을 형사적으로 해결하기를 원하여 재산범죄 고소를 남발하는 우리 사회 환경에서 우리 수사기관의 역량을 최대한 효율적으로 활용하기 위해서는 일정한 범위 내로 제한하는 것이 타당하다. 특정경제범죄 가중처벌 등에 관한 법률에서 규율하는 정도의 다액의 재산범죄, 기업형 사기범죄, 범죄단체에 의한 재산범죄 등이 그 예가 될 것이다. 우선 1차적으로는 해외에서 몰수된 범죄피해재산을 국내로 환수하여 피해자에게 환부할 수 있는 근거를 마련하는 것부터 시작하고 다음으로 대상 범위를 넓혀가는 것이 필요하다고 본다. The necessity and appropriateness of the protection of victims is not denied in any criminal theory. There are various legal arguments whether it is appropriate for the investigatory organization which is charged with identifying criminals and seeking punishment to intervene with the protection of victims through the recovering of criminal proceeds. Under the current Proceeds of Crime Act, the confiscation of victim s property of a predicate offense is prohibited so that victims themselves can file civil lawsuits for damage recovery. On the contrary America is adopting various systems for protection of victims such as restitution or remission. Recently Supreme Prosecutors’ Office collected criminal proceeds worth around 1 million dollars hidden in the U.S. with the help of U.S. Attorney s Office and distributed the proceeds to the local victims through remission process. It s the first case since we introduced our modern criminal justice system. As we didn t adopt remission system, this article is like a clinical test report. The purpose of this article is to provide the reader with actual practical information to judge whether the introduction of distribution of criminal proceeds to the victims like remission is right for our criminal justice system with a view to our social situation. Recovering of Criminal Proceeds to the Victims corresponds with both the constitutional clause on state duty to guarantee the human rights and basic purpose of the Crime Victim Protection Act. Distinction between civil law and criminal law in the area of protecting the victims from crime is becoming blurred in that every security net of society is aimed to control the illegal acts. At the early stage of fraud investigation, it is probably easy for law enforcement officers(LEOs) to detect hidden criminal proceeds. The criminals are inclined to cooperate with the LEOs to escape severe punishment. With the introduction of returning the criminal proceeds by the LEOs, both optimal punishment and recovering the proceeds to the victims can be pursued. But in our country, people have tendency to bring every civil case to the police or prosecutor s office. We need to limit the recovering criminal proceeds case. In my opinion the desirable case may be major fraud, Ponzi scheme, Pyramid scheme fraud and voice phishing by criminal organizations. Under the current circumstances, our first priority should be the revising the current asset recovery laws, allowing the government to distribute fraud proceeds recovered from overseas to local victims.

Mechanisms of Na adsorption on graphene and graphene oxide: density functional theory approach

Hye Sook Moon,Ji Hye Lee,Soonchul Kwon,Il Tae Kim,Seung Geol Lee 한국탄소학회 2015 Carbon Letters Vol.16 No.2

We investigated the adsorption of Na on graphene and graphene oxide, which are used as anode materials in sodium ion batteries, using density functional theory. The adsorption energy for Na on graphene was -0.507 eV at the hollow sites, implying that adsorption was favorable. In the case of graphene oxide, Na atoms were separately adsorbed on the epoxide and hydroxyl functional groups. The adsorption of Na on graphene oxide-epoxide (adsorption energy of -1.024 eV) was found to be stronger than the adsorption of Na on pristine graphene. However, the adsorption of Na on graphene oxide-hydroxyl resulted in the generation of NaOH as a by-product. Using density of states (DOS) calculations, we found that the DOS of the Na-adsorbed graphene was shifted down more than that of the Na-adsorbed graphene oxide-epoxide. In addition, the intensity of the DOS around the Fermi level for the Na-adsorbed graphene was higher than that for the Na-adsorbed graphene oxide-epoxide.

Effects of pairing correlations on the neutron skin thickness and the symmetry energy

Choi, Soonchul,Zhang, Ying,Cheoun, Myung-Ki,Kwon, Youngshin,Kim, Kyungsik,Kim, Hungchong American Physical Society 2017 Physical Review C Vol.96 No.2

<P>We investigated effects of pairing correlations on the neutron skin thickness and the symmetry energy of finite nuclei. In this calculation we used Hartree-Fock-Bogoliubov method with Skyrme forces and effective pairing interactions. The results have been compared with available experimental data, Hartree-Fock results as well as the predictions by droplet model. Finally, our discussion was extended to study of the pairing interaction in nuclear matter. Roles of isospin T = 0 pairing in the nuclear matter were also discussed.</P>

Implementation of On-site Audio Center based on AoIP

Jaeho Lee,Soonchul Kwon,Seunghyun Lee 한국인터넷방송통신학회 2017 Journal of Advanced Smart Convergence Vol.6 No.2

Recently, rapid advances of Ethernet and IP technology have brought many changes in the sound industry. In addition, due to AoIP-based audio transmission technology, various problems of the acoustic system (sound quality deterioration due to long distance transmission, complicated wiring) have improved dramatically. However, when many distributed audio systems are connected with AoIP equipment, if there is a problem in the equipment, it is impossible to operate the connected system. AoIP equipment only can transmit audio signals but cannot adjust the system for acoustic environment. In this paper, AoIP equipment is to be installed with sound equipment on a one-to-one basis, so that various existing problems can be solved and adjustment of sound quality (reverberation, echo, delay and EQ) can be possible by AoIP-based OAC (On-site Audio Center) with built-in DSP function. As a result, uncompressed real-time transmission by distributed transmission/receipt module in OAC (On-site Audio Center) and high quality sound by adjustment of sound quality with built-in DSP can be acquired. It is expected that OAC based sound system will be the industry standard in ubiquitous environment.