Tandem Solar Cells from Solution-Processed CdTe and PbS Quantum Dots Using a ZnTe–ZnO Tunnel Junction

Crisp, Ryan W.,Pach, Gregory F.,Kurley, J. Matthew,France, Ryan M.,Reese, Matthew O.,Nanayakkara, Sanjini U.,MacLeod, Bradley A.,Talapin, Dmitri V.,Beard, Matthew C.,Luther, Joseph M. American Chemical Society 2017 Nano letters Vol.17 No.2

<P>We developed a monolithic CdTe–PbS tandem solar cell architecture in which both the CdTe and PbS absorber layers are solution-processed from nanocrystal inks. Due to their tunable nature, PbS quantum dots (QDs), with a controllable band gap between 0.4 and ∼1.6 eV, are a promising candidate for a bottom absorber layer in tandem photovoltaics. In the detailed balance limit, the ideal configuration of a CdTe (<I>E</I><SUB>g</SUB> = 1.5 eV)–PbS tandem structure assumes infinite thickness of the absorber layers and requires the PbS band gap to be 0.75 eV to theoretically achieve a power conversion efficiency (PCE) of 45%. However, modeling shows that by allowing the thickness of the CdTe layer to vary, a tandem with efficiency over 40% is achievable using bottom cell band gaps ranging from 0.68 and 1.16 eV. In a first step toward developing this technology, we explore CdTe–PbS tandem devices by developing a ZnTe–ZnO tunnel junction, which appropriately combines the two subcells in series. We examine the basic characteristics of the solar cells as a function of layer thickness and bottom-cell band gap and demonstrate open-circuit voltages in excess of 1.1 V with matched short circuit current density of 10 mA/cm<SUP>2</SUP> in prototype devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2017/nalefd.2017.17.issue-2/acs.nanolett.6b04423/production/images/medium/nl-2016-04423k_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl6b04423'>ACS Electronic Supporting Info</A></P>

Durable Goods Secondary Market with Retailer-Level Competition

Ryan Choi,Taewan Kim,Eunkyu Lee 한국유통학회 2022 한국유통학회 학술대회 발표논문집 Vol.2022 No.10

Tubbataha Reefs Natural Park: the first comprehensive elasmobranch assessment reveals global hotspot for reef sharks

Ryan Murray,Segundo Conales Jr.,Gonzalo Araujo,Jessica Labaja,Sally J. Snow,Simon J. Pierce,Angelique Songco,Alessandro Ponzo 국립중앙과학관 2019 Journal of Asia-Pacific Biodiversity Vol.12 No.1

Elasmobranchs are experiencing population declines worldwide because of anthropogenic stressors. Marineprotected areas (MPAs) have been shown to benefit mesopredatory species of shark. The Tubbataha ReefsNatural Park (TRNP) is a United Nations Educational, Scientific and Cultural Organization World Heritage Siteand the largest no-take MPA in the Philippines, yet information on the current status of elasmobranchs in thepark is limited. Here, we investigate the abundance and biodiversity of elasmobranchs in TRNP using underwater visual census (UVC) and baited remote underwater video (BRUV) surveys. Twenty UVC wereconducted in May 2015 (n ¼ 10) and June 2016 (n ¼ 10), documenting eight species of elasmobranchs with anaverage density of 7.18 sharks ha-1 for both years. A total of 113 successful BRUV surveys were conducted inTRNP between MarcheJune 2015 (n ¼ 47) and AprileJune 2016 (n ¼ 66). The BRUV surveys recorded 14species with an average catch per unit effort of 2.09 elasmobranchs per hour for both years. Both surveymethods report some of the highest densities of the grey reef shark Carcharhinus amblyrhynchos and thewhitetip reef shark Triaenodon obesus documented worldwide. This study underlines the importance of large,well-managed MPAs such as TRNP for the conservation of reef-associated elasmobranchs.

An Exploratory Research on International Logistics Issues and Future Response Measures : Focused on Applying the Latest Technology

Ryan Sungpyo Sohn 한국전문경영인학회 2023 專門經營人硏究 Vol.26 No.4

최근 몇 년 동안 우리는 국제물류 공급망이 2023년까지는 정상 상황으로 복귀할 것이라고 예측하고 있었던 것이 사실이다. 그럼에도 불구하고 본 연구에서 Shopify의 2023년 E-commerce 통계에 따르면 응답자의 66%는 최근의 공급망 교란 문제가 2023년 이후 더욱 악화될 것으로 예상하고 있다. 이러한 결과는 지난 2년간의 글로벌 팬더믹의 영향에 서 안정적으로 회복하기 위한 지속적인 노력과 결합되어, 글로벌 물류 기업들이 공급망 불확실성의 미래를 대비하는 데에 집중하도록 하는 확실한 대응 방안들의 필요성을 대두 시켰다. 이에 배송 속도 저하, 재고 및 노동력 부족, 원자재 비용 상승, 운송 장애 등 글로벌 공급망의 원활한 네트워크 정상화를 가로막는 여러 이슈들은 지속적으로 전자상거 래 비즈니스에 중장기적인 영향을 미칠 것으로 조사되었다. 특히 본 연구에서 국제물류 수행기업 중 65%는 이익 마진이 감소하였으며 55%는 소비자 가격을 인상해야 한다고 평가하는 결과를 도출함에 따라, 물류 신기술 적용을 중심으로 하는 국제물류 고도화와 아울러 연구 결과로서의 향후 대응 방안을 함께 제시하려 한다. In recent years, we predict supply chains would return to their normal state by 2023. Despite this, 66% expect supply chain issues to worsen in 2023, according to Shopify's 2023 Commerce Statistics. This, combined with an ongoing effort to recover from the impacts of the last two years, is driving the best businesses to focus on preparing for a future of supply chain uncertainty. Historical supply chain disruptions such as slower shipping speeds, inventory and labor shortages, rising raw material costs, and transportation obstacles provoked long term effects on E-commerce business: 65% of those reported selling on their profit margins have decreased and 55% stated they had to increase customer prices. As mentioned above, we can derive research results related to recent international logistics, it is intended to present future response plans as a result of the research along with the advancement of international logistics focusing on the application of cutting-edge technologies.

Unraveling Inheritance of Ornamental Traits in Landscape Plants

Ryan N. Contreras 한국원예학회 2019 한국원예학회 학술발표요지 Vol.2019 No.5

Fusion of CNN and ORB Detection with Graph Convolutional Network for Enhancing Feature Discrimination

Ryan Febriansyah,신수용 한국통신학회 2023 韓國通信學會論文誌 Vol.48 No.10

A novel image classification scheme called ORB-GCN, which combines convolutional neural networks (CNNs) with features from Oriented and Rotated BRIEF (ORB) detection for a graph convolutional network (GCN). CNN models often encounter challenges in differentiating between similar features, leading to reduced interpretability and lower accuracy. Enhancing feature discrimination in local and global information is the goal of the ORB algorithm fusion for graph construction in GCN. By training CNN and ORB-GCN simultaneously and performing end-to-end classification, the proposed method effectively improves the discriminative ability of features compared to state-of-the-art methods. According to experiments on the MIT Indoor CVPR09 and Intel Image Scene datasets, the proposed ORB-GCN approach has the best accuracy.

치환 환기를 이용한 대기중 부유 분진 감소

Ryan Johnson,Chris Burroughs,김동규(번역자) 대한설비공학회 2023 설비저널 Vol.52 No.2

Cytokine profiles in intensive care unit delirium

Ryan J. Smith,Christian Lachner,Vijay P. Singh,Shubham Trivedi,Biswajit Khatua,Rodrigo Cartin-Ceba 대한중환자의학회 2022 Acute and Critical Care Vol.37 No.3

Background: Neuroinflammation causing disruption of the blood-brain barrier and immune cell extravasation into the brain parenchyma may cause delirium; however, knowledge of the exact pathophysiologic mechanism remains incomplete. The purpose of our study was to determine whether cytokine profiles differ depending on whether delirium occurs in the setting of sepsis, coronavirus disease 2019 (COVID-19), or recent surgery.Methods: This prospective observational cohort study involved 119 critically ill patients admitted to a multidisciplinary intensive care unit (ICU) during 2019 and 2020. Delirium was identified using the validated confusion assessment method for the ICU. Multiple delirium risk factors were collected daily including clinical characteristics, hospital course, lab values, vital signs, surgical exposure, drug exposure, and COVID-19 characteristics. Serums samples were collected within 12 hours of ICU admission and cytokine levels were measured.Results: The following proinflammatory cytokines were elevated in our delirium population: tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-18, C-C motif ligand (CCL) 2, CCL3, C-X-C motif chemokine ligand (CXCL)1, CXCL10, IL-8, IL-1 receptor antagonist, and IL-10. Analysis of relative cytokine levels in those patients that developed delirium in the setting of sepsis, COVID-19, and recent surgery showed elevations of CCL2, CXCL10, and TNF-α in both the sepsis and COVID-19 group in comparison to the postsurgical population. In the postsurgical group, granulocyte colony-stimulating factor was elevated and CXCL10 was decreased relative to the opposing groups.Conclusions: We identify several cytokines and precipitating factors known to be associated with delirium. However, our study suggests that the cytokine profile associated with delirium is variable and contingent upon delirium precipitating factors.

A Study on the Status of the ASEAN Halal Industry and Korea's Overseas Expansion Plan – Focusing on Entering Malaysia -

Ryan Sungpyo Sohn 한국무역금융보험학회(구 한국무역보험학회) 2021 무역보험연구 Vol.22 No.5

본 논문은 전 세계 200여 개가 넘는 할랄 인증 기관 중 가장 권위를 인정받고 있는 말레이시아 이슬람 개발부의 공식 할랄인증의 권위와 영향력을 중심으로, 아세안 할랄 산업의 현황과 관 련 정책 및 일반 법규, 국제 할랄 표준 개발 및 할랄 파크를 중심으로 하는 인프라 등을 분석하 고, 이를 토대로 우리나라의 해외 진출방안을 적극적으로 모색하는 것을 그 목적으로 한다. 할랄시장은 전세계 무슬림 인구 수의 급격한 증가, 이슬람 국가권의 경제 부상으로 인한 새로 운 중산층의 지속적 확대와 이슬람 가치 소비의 패러다임 변화 및 무슬림 온라인 시장의 성장 세를 중심으로 지속 성장하고 있는 고부가가치 창출 시장이다. 이에 국가문화적 특성을 활용하여 할랄 산업의 메카로 자리매김하려는 말레이시아의 정책적 어프로치와 할랄시장의 높은 성장 전망을 기반으로 관련 유망 산업군 및 제품군의 수출 경쟁 력을 가진 주력 수출 제품들을 선별함과 동시에, 우리나라 개별 기업의 전략적 투자 및 자원의 효율적적 배분 전략을 포괄적으로 분석하여 제공하였다. 할랄 허브를 국가 주요 정책 목표로 추진하고 있는 말레이시아 시장을 공략하기 위하여 한국 기업들이 진출할 수 있는 경쟁력있는 상품군의 확대와 아울러, 인증제도의 적극적 활용이라는 투트랙 전략을 효과적으로 활용하여야 할 것으로 분석되었다. 또한 한-ASEAN FTA를 적극 활용하여 제도 관련 비관세 장벽을 넘어섬으로써 향후 한국 기업 들이 무슬림 시장을 주도하기 위한 현지 시장의 심도있는 이해와 네트워크 구축에 진출 역량 을 집중하여야 할 것으로 분석되었다. Purpose : This study sought to resolve the current status of the ASEAN halal industry, related policies and regulations, development of halal standards, and various infrastructures, and to actively seek Korea's overseas expansion plans based on this. Research design, data, methodology : This study based on Malaysia's policy approach to establish itself as a mecca of the halal industry by utilizing national cultural characteristics and the high growth prospect of the halal market, it selects key export products with export competitiveness in relevant promising industries and product groups, and It aims to provide a comprehensive analysis of rational allocation strategies for investment and resources. Results : The results of the study express that in order for Korean companies to enter the Malaysian market, which aims to become a halal hub, they need to effectively utilize the two-track strategy of actively utilizing the certification system as well as expanding the competitive product group. Conclusions : In conclusion, By actively utilizing the Korea-ASEAN FTA to overcome the system-related non-tariff barriers, it is judged that Korean companies should focus their advancement capabilities on building networks and understanding the local market to lead the Muslim market in the future.

Optical and Electrical Properties of InAs/GaAs Quantum-dot Solar Cells

Ryan P. Smith,한임식,김종수,노삼규,임재영 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.6

We investigated the optical and the electrical properties of InAs quantum-dot solar cells (QDSCs)with various InAs deposition thicknesses () via photoluminescence (PL), spectral response (SR),and current density-voltage (J-V) measurements. We fabricated three QDSCs with thicknesses of2.0, 2.5, and 3.0 monolayers (MLs). Our measurements revealed the effects of the QD size onthe spectral response, the conversion efficiency (η) and the device parameters. The QDSCs had amaximum η of 17% for = 2.0 ML under AM1.5G conditions. The change of device parameters invarious QDSCs could be explained by the effects of the balance between enhanced carrier productionfrom the QD layers and carrier trapping/re-capturing by strain-induced defect/QD states.