Traditional chaotic maps struggle with narrow chaotic ranges and inefficiencies,limiting their use for lightweight,secure image encryption in resource-constrained Wireless Sensor Networks(WSNs).We propose the SPCM,a n...Traditional chaotic maps struggle with narrow chaotic ranges and inefficiencies,limiting their use for lightweight,secure image encryption in resource-constrained Wireless Sensor Networks(WSNs).We propose the SPCM,a novel one-dimensional discontinuous chaotic system integrating polynomial and sine functions,leveraging a piecewise function to achieve a broad chaotic range()and a high Lyapunov exponent(5.04).Validated through nine benchmarks,including standard randomness tests,Diehard tests,and Shannon entropy(3.883),SPCM demonstrates superior randomness and high sensitivity to initial conditions.Applied to image encryption,SPCM achieves 0.152582 s(39%faster than some techniques)and 433.42 KB/s throughput(134%higher than some techniques),setting new benchmarks for chaotic map-based methods in WSNs.Chaos-based permutation and exclusive or(XOR)diffusion yield near-zero correlation in encrypted images,ensuring strong resistance to Statistical Attacks(SA)and accurate recovery.SPCM also exhibits a strong avalanche effect(bit difference),making it an efficient,secure solution for WSNs in domains like healthcare and smart cities.展开更多
Bifunctional oxide-zeolite-based composites(OXZEO)have emerged as promising materials for the direct conversion of syngas to olefins.However,experimental screening and optimization of reaction parameters remain resour...Bifunctional oxide-zeolite-based composites(OXZEO)have emerged as promising materials for the direct conversion of syngas to olefins.However,experimental screening and optimization of reaction parameters remain resource-intensive.To address this challenge,we implemented a three-stage framework integrating machine learning,Bayesian optimization,and experimental validation,utilizing a carefully curated dataset from the literature.Our ensemble-tree model(R^(2)>0.87)identified Zn-Zr and Cu-Mg binary mixed oxides as the most effective OXZEO systems,with their light olefin space-time yields confirmed by physically mixing with HSAPO-34 through experimental validation.Density functional theory calculations further elucidated the activity trends between Zn-Zr and Cu-Mg mixed oxides.Among 16 catalyst and reaction condition descriptors,the oxide/zeolite ratio,reaction temperature,and pressure emerged as the most significant factors.This interpretable,data-driven framework offers a versatile approach that can be applied to other catalytic processes,providing a powerful tool for experiment design and optimization in catalysis.展开更多
Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen pro...Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen production technology based on the viable possibility of large-scale hydrogen production and the zero-carbon-emission nature of the process.However,for hydrogen produced via water electrolysis systems to be utilized in various fields in practice,the unit cost of hydrogen production must be reduced to$1/kg H_(2).To achieve this unit cost,technical targets for water electrolysis have been suggested regarding components in the system.In this paper,the types of water electrolysis systems and the limitations of water electrolysis system components are explained.We suggest guideline with recent trend for achieving this technical target and insights for the potential utilization of water electrolysis technology.展开更多
Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and i...Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and is regarded as a future technology for production of CO_(2)-free pure hydrogen.Herein,a heterostructural Pt-Ir dual-layer electrode is developed and shown to achieve successful long-term operation in an ammonia electrolyzer with an anion exchange membrane(AEM).This electrolyzer consisted of eight membra ne electrode assemblies(MEAs)with a total geometric area of 200 cm~2 on the anode side,which resulted in a hydrogen production rate of 25 L h~(-1).We observed the degradation in MEA performance attributed to changes in the anode catalyst layer during hydrogen production via ammonia electrolysis.Furthermore,we demonstrated the relationship between the ammonia oxidation reaction(AOR)and the oxygen evolution reaction(OER).展开更多
Over the years,zinc-ion batteries(ZIBs)have attracted attention as a promising next-generation energy storage technology because of their excellent safety,long cycling performance,eco-friendliness,and high-power densi...Over the years,zinc-ion batteries(ZIBs)have attracted attention as a promising next-generation energy storage technology because of their excellent safety,long cycling performance,eco-friendliness,and high-power density.However,issues,such as the corrosion and dissolution of the Zn anode,limited wet-tability,and lack of sufficient nucleation sites for Zn plating,have limited their practical application.The introduction of a protective layer comprising of tellurium(Te)nanobelts onto the surface of Zn anode has emerged as a promising approach to overcome these limitations and improve the electrochemical behav-ior by enhancing the safety and wettability of ZIBs,as well as providing numerous nucleation sites for Zn plating.In the presence of a Te-based protective layer,the energy power density of the surface-engineered Zn anode improved significantly(ranging from 310 to 144 W h kg^(-1),over a power density range of 270 to 1,800 W kg^(-1)),and the lifespan capability was extended.These results demonstrate that the proposed strategy of employing Te nanobelts as a protective layer holds great promise for enhancing the energy storage performance of zIBs,making them even more attractive as a viable energy storage solution forthefuture.展开更多
The functionalities and diverse metastable phases of multiferroic BiFeO_(3)(BFO)thin films depend on the misfit strain.Although mixed phase-induced strain relaxation in multiphase BFO thin films is well known,it is un...The functionalities and diverse metastable phases of multiferroic BiFeO_(3)(BFO)thin films depend on the misfit strain.Although mixed phase-induced strain relaxation in multiphase BFO thin films is well known,it is unclear whether a singlecrystalline BFO thin film can accommodate misfit strain without the involvement of its polymorphs.Thus,understanding the strain relaxation behavior is key to elucidating the lattice strain–property relationship.In this study,a correlative strain analysis based on dark-field inline electron holography(DIH)and quantitative scanning transmission electron microscopy(STEM)was performed to reveal the structural mechanism for strain accommodation of a single-crystalline BFO thin film.The nanoscale DIH strain analysis results indicated a random combination of multiple strain states that acted as a primary strain relief,forming irregularly strained nanodomains.The STEM-based bond length measurement of the corresponding strained nanodomains revealed a unique strain accommodation behavior achieved by a statistical combination of multiple modes of distorted structures on the unit-cell scale.The globally integrated strain for each nanodomain was estimated to be close to1.5%,irrespective of the nanoscale strain states,which was consistent with the fully strained BFO film on the SrTiO_(3) substrate.Density functional theory calculations suggested that strain accommodation by the combination of metastable phases was energetically favored compared to single-phase-mediated relaxation.This discovery allows a comprehensive understanding of strain accommodation behavior in ferroelectric oxide films,such as BFO,with various low-symmetry polymorphs.展开更多
AIM:To report preliminary results of the efficacy and safety of sunitinib in the management of Taiwan Residents gastrointestinal stromal tumors (GIST) patients facing imatinib mesylate (IM) intolerance or failure.METH...AIM:To report preliminary results of the efficacy and safety of sunitinib in the management of Taiwan Residents gastrointestinal stromal tumors (GIST) patients facing imatinib mesylate (IM) intolerance or failure.METHODS:Between 2001 and May 2010,199 Taiwan Residents patients with metastatic GIST were treated at Chang Gung Memorial Hospital.Among them,23 (11.6%) patients receiving sunitinib were investigated.RESULTS:Sixteen male and 7 female patients with a median age of 59 years (range:24-83 years) received sunitinib.Twenty-two GIST patients changed to sunitinib because of IM failure and 1 because of intolerance.The median duration of sunitinib administration was 6.0 mo (range:2-29 mo).The clinical benefit was 65.2% [2 complete response (CR),4 partial response (PR),and 9 stationary disease (SD);15/23].In 12 patients harboring mutations of the kit gene at exon 11,the clinical benefit rate (CR,PR,and SD) was 75.0% and 6 patients with tumors containing kit exon 9 mutations had a clinical benefit of 50.0% (not significant,P=0.344).The progression free survival (PFS) and overall survival (OS) did not differ between patients whose GISTs had wild type,KIT exon 9,or KIT exon 11 mutations.Hand-foot syndrome was the most common cause of grade Ⅲ adverse effect (26.1%),followed by anemia (17.4%),and neutropenia (13.0%).During the median 7.5-mo follow-up after sunitinib use,the median PFS and OS of these 23 GIST patients after sunitinib treatment were 8.4 and 14.1 mo,respectively.CONCLUSION:Sunitinib appears to be an effective treatment for Taiwan Residents with IM-resistant/intolerant GISTs and induced a sustained clinical benefit in more than 50% of Taiwan Residents advanced GIST patients.展开更多
We observe the influence of AI occupancies in Li sites on the formation process of the garnet solid elec- trolyte of Li_7La_3Zr_2O_12 （LLZO）. A direct incorporation of AI is first promoted in a Li-insufficient garne...We observe the influence of AI occupancies in Li sites on the formation process of the garnet solid elec- trolyte of Li_7La_3Zr_2O_12 （LLZO）. A direct incorporation of AI is first promoted in a Li-insufficient garnet solid electrolyte during the calcination process of 850 ℃ and then the cubic phase of LLZO is obtained after successive annealing step of 1000 ℃. Comparing to pristine LLZO, AI incorporated LLZO shows less formation of Li_2CO_3, keeping crystallographic and physicochemical properties. This AI incorporation im- proves both the ionic conductivity and interfacial resistance to poisoning procedure.展开更多
Biogeochemical cyclic activity of the ars (arsenic resistance system) operon is arsB influx/effux encoded by the ecological of Pseudomonas putida.This suggests that studying arsenite-oxidizing bacteria may lead to a b...Biogeochemical cyclic activity of the ars (arsenic resistance system) operon is arsB influx/effux encoded by the ecological of Pseudomonas putida.This suggests that studying arsenite-oxidizing bacteria may lead to a better understanding of molecular geomicrobiology,which can be applied to the bioremediation of arsenic-contaminated mines.This is the first report in which multiple arsB-binding mechanisms have been used on indigenous bacteria.In ArsB (strains OS-5; ABB83931; OS-19; ABB04282 and RW-28; ABB88574...展开更多
Nonnegative matrix factorization(NMF)has shown good performances on blind audio source separation(BASS).While the NMF analysis is a non-convex optimization problem when both the basis and encoding matrices need to be ...Nonnegative matrix factorization(NMF)has shown good performances on blind audio source separation(BASS).While the NMF analysis is a non-convex optimization problem when both the basis and encoding matrices need to be estimated simultaneously,the source separation step of the NMF-based BASS with a fixed basis matrix has been considered convex.However,because the basis matrix for the BASS is typically constructed by concatenating the basis matrices trained with individual source signals,the subspace spanned by the basis vectors for one source may overlap with that for other sources.In this paper,we have shown that the resulting encoding vector is not unique when the subspaces spanned by basis vectors for the sources overlap,which implies that the initialization of the encoding vector in the source separation stage is not trivial.Furthermore,we propose a novel method to initialize the encoding vector for the separation step based on the prior model of the encoding vector.Experimental results showed that the proposed method outperformed the uniform random initialization by 1.09 and 2.21dB in the source-to-distortion ratio,and 0.20 and 0.23 in PESQ scores for supervised and semi-supervised cases,respectively.展开更多
Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for wate...Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for water treatment. Graphene(rGO) has been intensively studied for CDI electrode because of its advantages such as excellent electrical conductivity and high specific surface area. However, its 2D dimensional structure with small specific capacitance, high resistance between layers and hydrophobicity degrades ion adsorption efficiency. In this work, we successfully prepared uniformly dispersed Fe3O4/rGO nanocomposite by simple thermal reactions and applied it as effective electrodes for CDI. Iron oxides play a role in uniting graphene sheets, and specific capacitance and wettability of electrodes are improved significantly;hence CDI performances are enhanced. The hardness removal of Fe3O4/rGO nanocomposite electrodes can reach 4.3 mg/g at applied voltage of 1.5V, which is 3 times higher than that of separate r GO electrodes.Thus this material is a promising candidate for water softening technology.展开更多
Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simp...Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.展开更多
Despite the scarcity and cost of iridium oxide,it is still the material of choice in numerous fields of science and applications,including capacitors,electrochromism,sensors,and various oxidation electrocatalysis(e.g....Despite the scarcity and cost of iridium oxide,it is still the material of choice in numerous fields of science and applications,including capacitors,electrochromism,sensors,and various oxidation electrocatalysis(e.g.,chlorine evolution reaction,detoxification,and oxygen evolution reaction).Such versatility is attributed to the distinct features of iridium oxides,such as their activity,biocompatibility,conductivity,and durability.The features and properties of iridium oxides are strongly dependent on the fabrication method.In this review,methodologies relating to the synthesis and fabrication of solid-state iridium oxides have been thoroughly collected and discussed.Structuring and crystallization techniques for iridium oxides are also noted.At the end of the review,the effects of utilizing a certain fabrication method on the characteristics of the iridium oxide product are recapitulated,together with the recommended application of the product in various fields.展开更多
Buffon’s needle experiment was originally devised to get the value of π. With the advent of computers, Buffon’s needle algorithm has been used pedagogically as an example of Monte Carlo methods in introduction clas...Buffon’s needle experiment was originally devised to get the value of π. With the advent of computers, Buffon’s needle algorithm has been used pedagogically as an example of Monte Carlo methods in introduction classes, and there are many Buffon’s needle algorithm implementations available on the internet. However, for the calculation of π, the exact value of π is used in the programs for Buffon’s needle angle sampling, and hence the example is not demonstrated correctly. This brief note presents a random angle sampling algorithm for the Buffon’s needle. We then compare the Buffon’s needle and Hit-and-Miss integration algorithms using Monte Carlo laboriousness comparison, and find that the Hit-and-Miss algorithm is superior.展开更多
Non-noble metals such as Fe and Ni have comparable electrocatalytic activity and stability to that of Ir and Ru in an oxygen evolution reaction (OER). In this study, we synthesized carbon nanofibers with embedded FeNi...Non-noble metals such as Fe and Ni have comparable electrocatalytic activity and stability to that of Ir and Ru in an oxygen evolution reaction (OER). In this study, we synthesized carbon nanofibers with embedded FeNi composites (FeNi-CNFs) as OER electrocatalysts by a facile route comprising electrospinning and the pyrolysis of a mixture of metal precursors and a polymer solution. FeNi-CNFs demonstrated catalytic activity and stability that were better than that of 20 wt% Ir on Vulcan carbon black in oxidizing water to produce oxygen in an alkaline media. Physicochemical and electrochemical characterization revealed that Fe and Ni had synergistic roles that enhanced OER activity by the uniform formation and widening of pores in the carbon structure, while the CNF matrix also contributed to the increased stability of the catalyst.展开更多
Of growing amount of food waste, the integrated food waste and waste water treatment was regarded as one of the efficient modeling method. However, the load of food waste to the conventional waste treatment process mi...Of growing amount of food waste, the integrated food waste and waste water treatment was regarded as one of the efficient modeling method. However, the load of food waste to the conventional waste treatment process might lead to the high concentration of total nitrogen（T-N） impact on the effluent water quality. The objective of this study is to establish two machine learning models-artificial neural networks（ANNs） and support vector machines（SVMs）, in order to predict 1-day interval T-N concentration of effluent from a wastewater treatment plant in Ulsan, Korea. Daily water quality data and meteorological data were used and the performance of both models was evaluated in terms of the coefficient of determination（R^2）, Nash-Sutcliff efficiency（NSE）, relative efficiency criteria（d rel）. Additionally, Latin-Hypercube one-factor-at-a-time（LH-OAT） and a pattern search algorithm were applied to sensitivity analysis and model parameter optimization, respectively. Results showed that both models could be effectively applied to the 1-day interval prediction of T-N concentration of effluent. SVM model showed a higher prediction accuracy in the training stage and similar result in the validation stage.However, the sensitivity analysis demonstrated that the ANN model was a superior model for 1-day interval T-N concentration prediction in terms of the cause-and-effect relationship between T-N concentration and modeling input values to integrated food waste and waste water treatment. This study suggested the efficient and robust nonlinear time-series modeling method for an early prediction of the water quality of integrated food waste and waste water treatment process.展开更多
Carbon surface with large oxygen and carbon ratio(O/C) indicated an outstanding electro-catalytic activity toward L-ascorbic acid oxidation, compared to platinum group metals. However, interrelation of surface functio...Carbon surface with large oxygen and carbon ratio(O/C) indicated an outstanding electro-catalytic activity toward L-ascorbic acid oxidation, compared to platinum group metals. However, interrelation of surface functional groups and its electro-catalytic activity is still unclear. In this paper, we prepared different levels of oxidized carbons by a simple acid treatment and investigated the correlation between the surface oxygen functional groups of acid-treated carbon and electro-catalytic activity in an electrooxidation of L-ascorbic acid. Positively charged carbon was demonstrated by lone pair electron of oxygen from valence band spectra study. It was revealed that the positively charged carbon, especially involved in carbonyl, showed enhanced the electro-catalytic activity through both better adsorption of negatively charged reactants and lowered LUMO by electronegativity of oxygen.展开更多
With the increase in silver（Ag）-based products in our lives, it is essential to test the potential toxicity of silver nanoparticles（Ag NPs） and silver ions（Ag ions） on living organisms under various conditions. ...With the increase in silver（Ag）-based products in our lives, it is essential to test the potential toxicity of silver nanoparticles（Ag NPs） and silver ions（Ag ions） on living organisms under various conditions. Here, we investigated the toxicity of Ag NPs with Ag ions to Escherichia coli K-12 strain under various conditions. We observed that both Ag NPs and Ag ions display antibacterial activities, and that Ag ions had higher toxicity to E. coli K-12 strain than Ag NPs under the same concentrations. To understand the toxicity of Ag NPs at a cellular level, reactive oxygen species（ROS） enzymes were detected for use as antioxidant enzymatic biomarkers. We have also studied the toxicity of Ag NPs and Ag ions under various coexistence conditions including： fixed total concentration, with a varied the ratio of Ag NPs to Ag ions; fixed the Ag NPs concentration and then increased the Ag ions concentration; fixed Ag ions concentration and then increasing the Ag NPs concentration.Exposure to Ag NPs and Ag ions clearly had synergistic toxicity; however, decreased toxicity（for a fixed Ag NPs concentration of 5 mg/L, after increasing the Ag ions concentration） to E. coli K-12 strain. Ag NPs and Ag ions in the presence of L-cysteine accelerated the bacterial cell growth rate, thereby reducing the bioavailability of Ag ions released from Ag NPs under the single and coexistence conditions. Further works are needed to consider this potential for Ag NPs and Ag ions toxicity across a range of environmental conditions.Environmental Significance Statement： As silver nanoparticles（Ag NPs）-based products are being broadly used in commercial industries, an ecotoxicological understanding of the Ag NPs being released into the environment should be further considered. Here, we investigate the comparative toxicity of Ag NPs and silver ions（Ag ions） to Escherichia coli K-12 strain, a representative ecotoxicological bioreporter. This study showed that toxicities of Ag NPs and Ag ions to E. coli K-12 strain display different relationships when existing individually or when coexisting, and in the presence of L-cysteine materials. These findings suggest that the toxicology research of nanomaterials should consider conditions when NPs coexist with and without their bioavailable ions.展开更多
In this paper, we propose a new algorithm for temporally consistent depth map estimation to generate three-dimensional video. The proposed algorithm adaptively computes the matching cost using a temporal weighting fun...In this paper, we propose a new algorithm for temporally consistent depth map estimation to generate three-dimensional video. The proposed algorithm adaptively computes the matching cost using a temporal weighting function, which is obtained by block-based moving object detection and motion estimation with variable block sizes. Experimental results show that the proposed algorithm improves the temporal consistency of the depth video and reduces by about 38% both the flickering artefact in the synthesized view and the number of coding bits for depth video coding.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government Ministry of Science and ICT(MIST)(RS-2022-00165225).
文摘Traditional chaotic maps struggle with narrow chaotic ranges and inefficiencies,limiting their use for lightweight,secure image encryption in resource-constrained Wireless Sensor Networks(WSNs).We propose the SPCM,a novel one-dimensional discontinuous chaotic system integrating polynomial and sine functions,leveraging a piecewise function to achieve a broad chaotic range()and a high Lyapunov exponent(5.04).Validated through nine benchmarks,including standard randomness tests,Diehard tests,and Shannon entropy(3.883),SPCM demonstrates superior randomness and high sensitivity to initial conditions.Applied to image encryption,SPCM achieves 0.152582 s(39%faster than some techniques)and 433.42 KB/s throughput(134%higher than some techniques),setting new benchmarks for chaotic map-based methods in WSNs.Chaos-based permutation and exclusive or(XOR)diffusion yield near-zero correlation in encrypted images,ensuring strong resistance to Statistical Attacks(SA)and accurate recovery.SPCM also exhibits a strong avalanche effect(bit difference),making it an efficient,secure solution for WSNs in domains like healthcare and smart cities.
基金funded by the KRICT Project (KK2512-10) of the Korea Research Institute of Chemical Technology and the Ministry of Trade, Industry and Energy (MOTIE)the Korea Institute for Advancement of Technology (KIAT) through the Virtual Engineering Platform Program (P0022334)+1 种基金supported by the Carbon Neutral Industrial Strategic Technology Development Program (RS-202300261088) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea)Further support was provided by research fund of Chungnam National University。
文摘Bifunctional oxide-zeolite-based composites(OXZEO)have emerged as promising materials for the direct conversion of syngas to olefins.However,experimental screening and optimization of reaction parameters remain resource-intensive.To address this challenge,we implemented a three-stage framework integrating machine learning,Bayesian optimization,and experimental validation,utilizing a carefully curated dataset from the literature.Our ensemble-tree model(R^(2)>0.87)identified Zn-Zr and Cu-Mg binary mixed oxides as the most effective OXZEO systems,with their light olefin space-time yields confirmed by physically mixing with HSAPO-34 through experimental validation.Density functional theory calculations further elucidated the activity trends between Zn-Zr and Cu-Mg mixed oxides.Among 16 catalyst and reaction condition descriptors,the oxide/zeolite ratio,reaction temperature,and pressure emerged as the most significant factors.This interpretable,data-driven framework offers a versatile approach that can be applied to other catalytic processes,providing a powerful tool for experiment design and optimization in catalysis.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant from the Ministry of Trade,Industry&Energy,Republic of Korea(No.20213030040590)the National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(NRF-2021K1A4A8A01079455)。
文摘Continuous efforts are underway to reduce carbon emissions worldwide in response to global climate change.Water electrolysis technology,in conjunction with renewable energy,is considered the most feasible hydrogen production technology based on the viable possibility of large-scale hydrogen production and the zero-carbon-emission nature of the process.However,for hydrogen produced via water electrolysis systems to be utilized in various fields in practice,the unit cost of hydrogen production must be reduced to$1/kg H_(2).To achieve this unit cost,technical targets for water electrolysis have been suggested regarding components in the system.In this paper,the types of water electrolysis systems and the limitations of water electrolysis system components are explained.We suggest guideline with recent trend for achieving this technical target and insights for the potential utilization of water electrolysis technology.
基金supported by the research program funded by the TKG Huchemssupported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)granted financial resources from the Ministry of Trade,Industry&Energy,Republic of Korea(20213030040590)supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(2021R1A5A1028138)。
文摘Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and is regarded as a future technology for production of CO_(2)-free pure hydrogen.Herein,a heterostructural Pt-Ir dual-layer electrode is developed and shown to achieve successful long-term operation in an ammonia electrolyzer with an anion exchange membrane(AEM).This electrolyzer consisted of eight membra ne electrode assemblies(MEAs)with a total geometric area of 200 cm~2 on the anode side,which resulted in a hydrogen production rate of 25 L h~(-1).We observed the degradation in MEA performance attributed to changes in the anode catalyst layer during hydrogen production via ammonia electrolysis.Furthermore,we demonstrated the relationship between the ammonia oxidation reaction(AOR)and the oxygen evolution reaction(OER).
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Korea government(MOTIE)(RS-2023-00303581,Multiscale Simulation-Driven Development of Cost-Effective and Stable Aqueous Zn Ion Battery with Energy Density of 110 Wh/L for Energy Storage Systems:A Korea-USA Collaboration)。
文摘Over the years,zinc-ion batteries(ZIBs)have attracted attention as a promising next-generation energy storage technology because of their excellent safety,long cycling performance,eco-friendliness,and high-power density.However,issues,such as the corrosion and dissolution of the Zn anode,limited wet-tability,and lack of sufficient nucleation sites for Zn plating,have limited their practical application.The introduction of a protective layer comprising of tellurium(Te)nanobelts onto the surface of Zn anode has emerged as a promising approach to overcome these limitations and improve the electrochemical behav-ior by enhancing the safety and wettability of ZIBs,as well as providing numerous nucleation sites for Zn plating.In the presence of a Te-based protective layer,the energy power density of the surface-engineered Zn anode improved significantly(ranging from 310 to 144 W h kg^(-1),over a power density range of 270 to 1,800 W kg^(-1)),and the lifespan capability was extended.These results demonstrate that the proposed strategy of employing Te nanobelts as a protective layer holds great promise for enhancing the energy storage performance of zIBs,making them even more attractive as a viable energy storage solution forthefuture.
基金Samsung Research Fundings&Incubation Center of Samsung Electronics(Grant No.SRFCMA1702-01)Y.-M.K acknowledges partial support from the National Research Foundation of Korea(NRF)(Grant No.2023R1A2C2002403)funded by the Korean government in KoreaA.Borisevich acknowledges support from FaCT,an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Office of Basic Energy Science,Collaboratives Research Division.
文摘The functionalities and diverse metastable phases of multiferroic BiFeO_(3)(BFO)thin films depend on the misfit strain.Although mixed phase-induced strain relaxation in multiphase BFO thin films is well known,it is unclear whether a singlecrystalline BFO thin film can accommodate misfit strain without the involvement of its polymorphs.Thus,understanding the strain relaxation behavior is key to elucidating the lattice strain–property relationship.In this study,a correlative strain analysis based on dark-field inline electron holography(DIH)and quantitative scanning transmission electron microscopy(STEM)was performed to reveal the structural mechanism for strain accommodation of a single-crystalline BFO thin film.The nanoscale DIH strain analysis results indicated a random combination of multiple strain states that acted as a primary strain relief,forming irregularly strained nanodomains.The STEM-based bond length measurement of the corresponding strained nanodomains revealed a unique strain accommodation behavior achieved by a statistical combination of multiple modes of distorted structures on the unit-cell scale.The globally integrated strain for each nanodomain was estimated to be close to1.5%,irrespective of the nanoscale strain states,which was consistent with the fully strained BFO film on the SrTiO_(3) substrate.Density functional theory calculations suggested that strain accommodation by the combination of metastable phases was energetically favored compared to single-phase-mediated relaxation.This discovery allows a comprehensive understanding of strain accommodation behavior in ferroelectric oxide films,such as BFO,with various low-symmetry polymorphs.
基金Supported by Chang Gung Medical Research Program 380711 Grant to Dr. Yeh CN
文摘AIM:To report preliminary results of the efficacy and safety of sunitinib in the management of Taiwan Residents gastrointestinal stromal tumors (GIST) patients facing imatinib mesylate (IM) intolerance or failure.METHODS:Between 2001 and May 2010,199 Taiwan Residents patients with metastatic GIST were treated at Chang Gung Memorial Hospital.Among them,23 (11.6%) patients receiving sunitinib were investigated.RESULTS:Sixteen male and 7 female patients with a median age of 59 years (range:24-83 years) received sunitinib.Twenty-two GIST patients changed to sunitinib because of IM failure and 1 because of intolerance.The median duration of sunitinib administration was 6.0 mo (range:2-29 mo).The clinical benefit was 65.2% [2 complete response (CR),4 partial response (PR),and 9 stationary disease (SD);15/23].In 12 patients harboring mutations of the kit gene at exon 11,the clinical benefit rate (CR,PR,and SD) was 75.0% and 6 patients with tumors containing kit exon 9 mutations had a clinical benefit of 50.0% (not significant,P=0.344).The progression free survival (PFS) and overall survival (OS) did not differ between patients whose GISTs had wild type,KIT exon 9,or KIT exon 11 mutations.Hand-foot syndrome was the most common cause of grade Ⅲ adverse effect (26.1%),followed by anemia (17.4%),and neutropenia (13.0%).During the median 7.5-mo follow-up after sunitinib use,the median PFS and OS of these 23 GIST patients after sunitinib treatment were 8.4 and 14.1 mo,respectively.CONCLUSION:Sunitinib appears to be an effective treatment for Taiwan Residents with IM-resistant/intolerant GISTs and induced a sustained clinical benefit in more than 50% of Taiwan Residents advanced GIST patients.
基金financial support from the R&D Convergence Program (CAP-14-02-KITECH)the National Research Council of Science & Technology of the Republic of Korea
文摘We observe the influence of AI occupancies in Li sites on the formation process of the garnet solid elec- trolyte of Li_7La_3Zr_2O_12 （LLZO）. A direct incorporation of AI is first promoted in a Li-insufficient garnet solid electrolyte during the calcination process of 850 ℃ and then the cubic phase of LLZO is obtained after successive annealing step of 1000 ℃. Comparing to pristine LLZO, AI incorporated LLZO shows less formation of Li_2CO_3, keeping crystallographic and physicochemical properties. This AI incorporation im- proves both the ionic conductivity and interfacial resistance to poisoning procedure.
基金the Korea Science and Engineering Foundation (KOSEF) through the National Research Lab.Program funded by the Korean Ministry of Science and Technology (No.M10300000298-06J0000-29810).
文摘Biogeochemical cyclic activity of the ars (arsenic resistance system) operon is arsB influx/effux encoded by the ecological of Pseudomonas putida.This suggests that studying arsenite-oxidizing bacteria may lead to a better understanding of molecular geomicrobiology,which can be applied to the bioremediation of arsenic-contaminated mines.This is the first report in which multiple arsB-binding mechanisms have been used on indigenous bacteria.In ArsB (strains OS-5; ABB83931; OS-19; ABB04282 and RW-28; ABB88574...
基金supported by the research fund of Signal Intelligence Research Center supervised by the Defense Acquisition Program Administration and Agency for Defense Development of Korea
文摘Nonnegative matrix factorization(NMF)has shown good performances on blind audio source separation(BASS).While the NMF analysis is a non-convex optimization problem when both the basis and encoding matrices need to be estimated simultaneously,the source separation step of the NMF-based BASS with a fixed basis matrix has been considered convex.However,because the basis matrix for the BASS is typically constructed by concatenating the basis matrices trained with individual source signals,the subspace spanned by the basis vectors for one source may overlap with that for other sources.In this paper,we have shown that the resulting encoding vector is not unique when the subspaces spanned by basis vectors for the sources overlap,which implies that the initialization of the encoding vector in the source separation stage is not trivial.Furthermore,we propose a novel method to initialize the encoding vector for the separation step based on the prior model of the encoding vector.Experimental results showed that the proposed method outperformed the uniform random initialization by 1.09 and 2.21dB in the source-to-distortion ratio,and 0.20 and 0.23 in PESQ scores for supervised and semi-supervised cases,respectively.
基金supported by international cooperation program for science and technology funded by the Ministry of Science,ICT&Future Planning(NRF-2014K1A3A1A09063208)
文摘Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for water treatment. Graphene(rGO) has been intensively studied for CDI electrode because of its advantages such as excellent electrical conductivity and high specific surface area. However, its 2D dimensional structure with small specific capacitance, high resistance between layers and hydrophobicity degrades ion adsorption efficiency. In this work, we successfully prepared uniformly dispersed Fe3O4/rGO nanocomposite by simple thermal reactions and applied it as effective electrodes for CDI. Iron oxides play a role in uniting graphene sheets, and specific capacitance and wettability of electrodes are improved significantly;hence CDI performances are enhanced. The hardness removal of Fe3O4/rGO nanocomposite electrodes can reach 4.3 mg/g at applied voltage of 1.5V, which is 3 times higher than that of separate r GO electrodes.Thus this material is a promising candidate for water softening technology.
文摘Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.
基金supported by the Technology Development Program to Solve Climate Change through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT(2018M1A2A2063861)supported by the GIST Research Institute(GRI)grant funded by the GIST in 2019。
文摘Despite the scarcity and cost of iridium oxide,it is still the material of choice in numerous fields of science and applications,including capacitors,electrochromism,sensors,and various oxidation electrocatalysis(e.g.,chlorine evolution reaction,detoxification,and oxygen evolution reaction).Such versatility is attributed to the distinct features of iridium oxides,such as their activity,biocompatibility,conductivity,and durability.The features and properties of iridium oxides are strongly dependent on the fabrication method.In this review,methodologies relating to the synthesis and fabrication of solid-state iridium oxides have been thoroughly collected and discussed.Structuring and crystallization techniques for iridium oxides are also noted.At the end of the review,the effects of utilizing a certain fabrication method on the characteristics of the iridium oxide product are recapitulated,together with the recommended application of the product in various fields.
文摘Buffon’s needle experiment was originally devised to get the value of π. With the advent of computers, Buffon’s needle algorithm has been used pedagogically as an example of Monte Carlo methods in introduction classes, and there are many Buffon’s needle algorithm implementations available on the internet. However, for the calculation of π, the exact value of π is used in the programs for Buffon’s needle angle sampling, and hence the example is not demonstrated correctly. This brief note presents a random angle sampling algorithm for the Buffon’s needle. We then compare the Buffon’s needle and Hit-and-Miss integration algorithms using Monte Carlo laboriousness comparison, and find that the Hit-and-Miss algorithm is superior.
文摘Non-noble metals such as Fe and Ni have comparable electrocatalytic activity and stability to that of Ir and Ru in an oxygen evolution reaction (OER). In this study, we synthesized carbon nanofibers with embedded FeNi composites (FeNi-CNFs) as OER electrocatalysts by a facile route comprising electrospinning and the pyrolysis of a mixture of metal precursors and a polymer solution. FeNi-CNFs demonstrated catalytic activity and stability that were better than that of 20 wt% Ir on Vulcan carbon black in oxidizing water to produce oxygen in an alkaline media. Physicochemical and electrochemical characterization revealed that Fe and Ni had synergistic roles that enhanced OER activity by the uniform formation and widening of pores in the carbon structure, while the CNF matrix also contributed to the increased stability of the catalyst.
基金supported by a grant (12-TI-C04) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government
文摘Of growing amount of food waste, the integrated food waste and waste water treatment was regarded as one of the efficient modeling method. However, the load of food waste to the conventional waste treatment process might lead to the high concentration of total nitrogen（T-N） impact on the effluent water quality. The objective of this study is to establish two machine learning models-artificial neural networks（ANNs） and support vector machines（SVMs）, in order to predict 1-day interval T-N concentration of effluent from a wastewater treatment plant in Ulsan, Korea. Daily water quality data and meteorological data were used and the performance of both models was evaluated in terms of the coefficient of determination（R^2）, Nash-Sutcliff efficiency（NSE）, relative efficiency criteria（d rel）. Additionally, Latin-Hypercube one-factor-at-a-time（LH-OAT） and a pattern search algorithm were applied to sensitivity analysis and model parameter optimization, respectively. Results showed that both models could be effectively applied to the 1-day interval prediction of T-N concentration of effluent. SVM model showed a higher prediction accuracy in the training stage and similar result in the validation stage.However, the sensitivity analysis demonstrated that the ANN model was a superior model for 1-day interval T-N concentration prediction in terms of the cause-and-effect relationship between T-N concentration and modeling input values to integrated food waste and waste water treatment. This study suggested the efficient and robust nonlinear time-series modeling method for an early prediction of the water quality of integrated food waste and waste water treatment process.
基金supported by the New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (20153030031720)
文摘Carbon surface with large oxygen and carbon ratio(O/C) indicated an outstanding electro-catalytic activity toward L-ascorbic acid oxidation, compared to platinum group metals. However, interrelation of surface functional groups and its electro-catalytic activity is still unclear. In this paper, we prepared different levels of oxidized carbons by a simple acid treatment and investigated the correlation between the surface oxygen functional groups of acid-treated carbon and electro-catalytic activity in an electrooxidation of L-ascorbic acid. Positively charged carbon was demonstrated by lone pair electron of oxygen from valence band spectra study. It was revealed that the positively charged carbon, especially involved in carbonyl, showed enhanced the electro-catalytic activity through both better adsorption of negatively charged reactants and lowered LUMO by electronegativity of oxygen.
基金supported through the National Research Foundation of Korea (No. 2013R1A1A1007708)
文摘With the increase in silver（Ag）-based products in our lives, it is essential to test the potential toxicity of silver nanoparticles（Ag NPs） and silver ions（Ag ions） on living organisms under various conditions. Here, we investigated the toxicity of Ag NPs with Ag ions to Escherichia coli K-12 strain under various conditions. We observed that both Ag NPs and Ag ions display antibacterial activities, and that Ag ions had higher toxicity to E. coli K-12 strain than Ag NPs under the same concentrations. To understand the toxicity of Ag NPs at a cellular level, reactive oxygen species（ROS） enzymes were detected for use as antioxidant enzymatic biomarkers. We have also studied the toxicity of Ag NPs and Ag ions under various coexistence conditions including： fixed total concentration, with a varied the ratio of Ag NPs to Ag ions; fixed the Ag NPs concentration and then increased the Ag ions concentration; fixed Ag ions concentration and then increasing the Ag NPs concentration.Exposure to Ag NPs and Ag ions clearly had synergistic toxicity; however, decreased toxicity（for a fixed Ag NPs concentration of 5 mg/L, after increasing the Ag ions concentration） to E. coli K-12 strain. Ag NPs and Ag ions in the presence of L-cysteine accelerated the bacterial cell growth rate, thereby reducing the bioavailability of Ag ions released from Ag NPs under the single and coexistence conditions. Further works are needed to consider this potential for Ag NPs and Ag ions toxicity across a range of environmental conditions.Environmental Significance Statement： As silver nanoparticles（Ag NPs）-based products are being broadly used in commercial industries, an ecotoxicological understanding of the Ag NPs being released into the environment should be further considered. Here, we investigate the comparative toxicity of Ag NPs and silver ions（Ag ions） to Escherichia coli K-12 strain, a representative ecotoxicological bioreporter. This study showed that toxicities of Ag NPs and Ag ions to E. coli K-12 strain display different relationships when existing individually or when coexisting, and in the presence of L-cysteine materials. These findings suggest that the toxicology research of nanomaterials should consider conditions when NPs coexist with and without their bioavailable ions.
基金supported by the National Research Foundation of Korea Grant funded by the Korea Ministry of Science and Technology under Grant No. 2012-0009228
文摘In this paper, we propose a new algorithm for temporally consistent depth map estimation to generate three-dimensional video. The proposed algorithm adaptively computes the matching cost using a temporal weighting function, which is obtained by block-based moving object detection and motion estimation with variable block sizes. Experimental results show that the proposed algorithm improves the temporal consistency of the depth video and reduces by about 38% both the flickering artefact in the synthesized view and the number of coding bits for depth video coding.
