Sanghwi Han;Jae Hyun Ryu;Won Bo Lee;Jaeyune Ryu;Jeyong Yoon; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(27):2311052

Development of robust electrocatalysts for the oxygen evolution reaction (OER) underpins the efficient production of green hydrogen via anion exchange membrane water electrolysis (AEMWE). This study elucidates the factors contributing to the degradation of cobalt-based (Co-based) OER catalysts synthesized via electrodeposition, thus establishing strategic approaches to enhance their longevity. Systematic variations in the electroplating process and subsequent heat treatment reveal a delicate balance between catalytic activity and durability, substantiated by comprehensive electrochemical assessments and material analyses. Building upon these findings, the Co-based anode is successfully optimized in the AEMWE single-cell configuration, showcasing an average degradation rate of 0.07 mV h−1 over a continuous operation for 1500 h at a current density of 1 A cm−2.  相似文献   

    

Jongmin Lee  Hongji Yoon  Kyoung Soon Choi  Seungkyu Kim  Sehun Seo  Jaesun Song  Byeong‐Uk Choi  Jiseung Ryu  Sangwoo Ryu  Jihun Oh  Cheolho Jeon  Sanghan Lee 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(39)

To develop strategies for efficient photo‐electrochemical water‐splitting, it is important to understand the fundamental properties of oxide photoelectrodes by synthesizing and investigating their single‐crystal thin films. However, it is challenging to synthesize high‐quality single‐crystal thin films from copper‐based oxide photoelectrodes due to the occurrence of significant defects such as copper or oxygen vacancies and grains. Here, the CuBi₂O₄ (CBO) single‐crystal thin film photocathode is achieved using a NiO template layer grown on single‐crystal SrTiO₃ (STO) (001) substrate via pulsed laser deposition. The NiO template layer plays a role as a buffer layer of large lattice mismatch between CBO and STO (001) substrate through domain‐matching epitaxy, and forms a type‐II band alignment with CBO, which prohibits the transfer of photogenerated electrons toward bottom electrode. The photocurrent densities of the CBO single‐crystal thin film photocathode demonstrate ?0.4 and ?0.7 mA cm^?2 at even 0 V_RHE with no severe dark current under illumination in a 0.1 m potassium phosphate buffer solution without and with H₂O₂ as an electron scavenger, respectively. The successful synthesis of high‐quality CBO single‐crystal thin film would be a cornerstone for the in‐depth understanding of the fundamental properties of CBO toward efficient photo‐electrochemical water‐splitting.  相似文献   

    

Ning An  Yunhao Cai  Hongbo Wu  Ailing Tang  Kangning Zhang  Xiaotao Hao  Zaifei Ma  Qiang Guo  Hwa Sook Ryu  Han Young Woo  Yanming Sun  Erjun Zhou 《Advanced materials (Deerfield Beach, Fla.)》2020,32(39):2002122

Compared with inorganic or perovskite solar cells, the relatively large non-radiative recombination voltage losses (ΔV_non-rad) in organic solar cells (OSCs) limit the improvement of the open-circuit voltage (V_oc). Herein, OSCs are fabricated by adopting two pairs of D–π–A polymers (PBT1-C/PBT1-C-2Cl and PBDB-T/PBDB-T-2Cl) as electron donors and a wide-bandgap molecule BTA3 as the electron acceptor. In these blends, a charge-transfer state energy (E_CT) as high as 1.70–1.76 eV is achieved, leading to small energetic differences between the singlet excited states and charge-transfer states (ΔE_CT ≈ 0.1 eV). In addition, after introducing chlorine atoms into the π-bridge or the side chain of benzodithiophene (BDT) unit, electroluminescence external quantum efficiencies as high as 1.9 × 10⁻³ and 1.0 × 10⁻³ are realized in OSCs based on PBTI-C-2Cl and PBDB-T-2Cl, respectively. Their corresponding ΔV_non-rad are 0.16 and 0.17 V, which are lower than those of OSCs based on the analog polymers without a chlorine atom (0.21 and 0.24 V for PBT1-C and PBDB-T, respectively), resulting in high V_oc of 1.3 V. The ΔV_non-rad of 0.16 V and V_oc of 1.3 V achieved in PBT1-C-2Cl:BTA3 OSCs are thought to represent the best values for solution-processed OSCs reported in the literature so far.  相似文献   

    

Mikyung Kang  Jihye Hong  Mungyo Jung  Sung Pil Kwon  Seuk Young Song  Han Young Kim  Ju-Ro Lee  Seokyung Kang  Jin Han  Ja-Hyun Koo  Ju Hee Ryu  Songhyun Lim  Hee Su Sohn  Je-Min Choi  Junsang Doh  Byung-Soo Kim 《Advanced materials (Deerfield Beach, Fla.)》2020,32(39):2003368

Cancer immunotherapies, including adoptive T cell transfer and immune checkpoint blockades, have recently shown considerable success in cancer treatment. Nevertheless, transferred T cells often become exhausted because of the immunosuppressive tumor microenvironment. Immune checkpoint blockades, in contrast, can reinvigorate the exhausted T cells; however, the therapeutic efficacy is modest in 70–80% of patients. To address some of the challenges faced by the current cancer treatments, here T-cell-membrane-coated nanoparticles (TCMNPs) are developed for cancer immunotherapy. Similar to cytotoxic T cells, TCMNPs can be targeted at tumors via T-cell-membrane-originated proteins and kill cancer cells by releasing anticancer molecules and inducing Fas-ligand-mediated apoptosis. Unlike cytotoxic T cells, TCMNPs are resistant to immunosuppressive molecules (e.g., transforming growth factor-β1 (TGF-β1)) and programmed death-ligand 1 (PD-L1) of cancer cells by scavenging TGF-β1 and PD-L1. Indeed, TCMNPs exhibit higher therapeutic efficacy than an immune checkpoint blockade in melanoma treatment. Furthermore, the anti-tumoral actions of TCMNPs are also demonstrated in the treatment of lung cancer in an antigen-nonspecific manner. Taken together, TCMNPs have a potential to improve the current cancer immunotherapy.  相似文献   

    

Jaegeon Ryu  Woo‐Jin Song  Sangyeop Lee  Sungho Choi  Soojin Park 《Advanced functional materials》2020,30(2)

The imperative to electrify the transport sector in the past few decades has put millions of electric vehicles on the road worldwide with an extended mile range from critical technological breakthroughs in developing the rechargeable energy storage systems, which also covers electronic devices and smart grid applications. However, the available energy density of prevailing systems in the market (i.e., batteries) is reaching its boundaries due to the limited choice of electrochemical reactions that necessarily depend on the thermodynamics and kinetics of the components (e.g., cathode, anode, electrolyte, separator, and current collectors). Reaching the high energy density of batteries exploits new redox chemistry such as sensitive metal anodes, insulating and highly dissolving sulfur cathodes, etc., thus requiring novel designs of various multiscale functional materials to address the corresponding issues. Here, the recent achievements on the designs of smart functional materials for emerging problems in the whole range of systems are discussed: i) interfacial control/kinetic regulation of Li–S battery; ii) self‐healing‐driven structural stability in the electrode and electrolyte; iii) ion‐sieving functional membranes for selective scavenging capability; and iv) functional materials to ensure battery safety.  相似文献   

    

Sungjae Hwang  Sungho Lee  Sukyoung Ryu 《Software》2020,50(7):1061-1086

Android supports seamless user experience by maintaining activities from different applications (apps) in the same activity stack. Although such close inter-app communication is essential in the Android framework, the powerful inter-app communication contains vulnerabilities that can inject malicious activities into a victim app's activity stack to hijack user interaction flows. In this article, we demonstrate activity injection attacks with a simple malware, and formally specify the activity activation mechanism using operational semantics. Based on the operational semantics, we develop a static analysis tool, which analyzes Android apps to detect activity injection attacks. Our tool is fast enough to analyze real-world Android apps in 6 seconds on average, and our experiments found that 1761 apps out of 129,756 real-world Android apps inject their activities into other apps' tasks. Moreover, we propose a defense mechanism, dubbed signature-based activity access control (SAAC), which completely prohibits activity injection attacks. The defense mechanism is general enough to keep the current Android multitasking features intact, and it is simple enough to be independent of the complex activity activation semantics, which does not increase activity activation time noticeably. With the extension of the formal semantics for SAAC, we prove that SAAC correctly mitigates activity injection attacks without any false alarms.  相似文献   

    

Donggyu Lee  Daehee Lee  Yulim Won  Hyeonaug Hong  Yongjae Kim  Hyunwoo Song  Jae‐Chul Pyun  Yong Soo Cho  Wonhyoung Ryu  Jooho Moon 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(11):1446-1457

Effective insertion of vertically aligned nanowires (NWs) into cells is critical for bioelectrical and biochemical devices, biological delivery systems, and photosynthetic bioenergy harvesting. However, accurate insertion of NWs into living cells using scalable processes has not yet been achieved. Here, NWs are inserted into living Chlamydomonas reinhardtii cells (Chlamy cells) via inkjet printing of the Chlamy cells, representing a low‐cost and large‐scale method for inserting NWs into living cells. Jetting conditions and printable bioink composed of living Chlamy cells are optimized to achieve stable jetting and precise ink deposition of bioink for indentation of NWs into Chlamy cells. Fluorescence confocal microscopy is used to verify the viability of Chlamy cells after inkjet printing. Simple mechanical considerations of the cell membrane and droplet kinetics are developed to control the jetting force to allow penetration of the NWs into cells. The results suggest that inkjet printing is an effective, controllable tool for stable insertion of NWs into cells with economic and scale‐related advantages.  相似文献   

An Affordance-Based Model of Human Action Selection in a Human–Machine Interaction System with Cognitive Interpretations     

Hokyoung Ryu  Namhun Kim  Jangsun Lee  Dongmin Shin 《International journal of human-computer interaction》2016,32(5):402-414

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Tae‐Jin Kim  Changhoon Baek  Sengsub Chun  Kil‐Hoon Lee  Jong‐Il Hwang  Kyeonghwan Kwon  Yong‐Hun Kim  Hyun‐Sang Park  Youngmin Shin  Seong‐young Ryu  Jae‐Youl Lee  Gyoocheol Hwang  Gyeongnam Kim 《Journal of the Society for Information Display》2016,24(5):299-306

This paper presents a timing controller embedded driver (TED) IC with 3.24‐Gbps embedded display port (eDP), which is implemented using a 45‐nm high‐voltage CMOS process for the chip‐on‐glass (COG) TFT‐LCD applications. The proposed TED‐IC employs the input offset calibration scheme, the zero‐adjustable equalizer, and the phase locked loop‐based bang‐bang clock and data recovery to enhance the maximum data rate. Also, the proposed TED‐IC provides efficient power management by supporting advanced link power management feature of eDP standard v1.4. Additionally, the smart charge sharing is proposed to reduce the dynamic power consumption of output buffers. Measured result demonstrates the maximum data rate of 3.24 Gbps from a 1.1 V supply voltage with a 7.9‐inch QXGA 60‐Hz COG‐LCD prototype panel and 44% power saving from the display system.  相似文献   

    

Frejus Ariel Kpedetin Sodedji  Dahye Ryu  Jaeyoung Choi  Symphorien Agbahoungba  Achille Ephrem Assogbadjo  Simon-Pierre Assanvo N&#x;Guetta  Je Hyeong Jung  Chu Won Nho  Ho-Youn Kim 《International journal of molecular sciences》2022,23(7)

The development and promotion of biofortified foods plants are a sustainable strategy for supplying essential micronutrients for human health and nutrition. We set out to identify quantitative trait loci (QTL) associated with carotenoid content in cowpea sprouts. The contents of carotenoids, including lutein, zeaxanthin, and β-carotene in sprouts of 125 accessions were quantified via high-performance liquid chromatography. Significant variation existed in the profiles of the different carotenoids. Lutein was the most abundant (58 ± 12.8 mg/100 g), followed by zeaxanthin (14.7 ± 3.1 mg/100 g) and β-carotene (13.2 ± 2.9 mg/100 g). A strong positive correlation was observed among the carotenoid compounds (r ≥ 0.87), indicating they can be improved concurrently. The accessions were distributed into three groups, following their carotenoid profiles, with accession C044 having the highest sprout carotenoid content in a single cluster. A total of 3120 genome-wide SNPs were tested for association analysis, which revealed that carotenoid biosynthesis in cowpea sprouts is a polygenic trait controlled by genes with additive and dominance effects. Seven loci were significantly associated with the variation in carotenoid content. The evidence of variation in carotenoid content and genomic regions controlling the trait creates an avenue for breeding cowpea varieties with enhanced sprouts carotenoid content.  相似文献