Blockchain technology and crowdfunding(CF)have emerged as disruptive forces in the finance and entrepreneurship landscape,potentially transforming traditional modes of capital raising and investment.This study investi...Blockchain technology and crowdfunding(CF)have emerged as disruptive forces in the finance and entrepreneurship landscape,potentially transforming traditional modes of capital raising and investment.This study investigates the intersection of blockchain technology and CF to provide a comprehensive overview of the current state of research through a systematic literature review and bibliometric analysis.By examining 219 publications sourced from Scopus,this study employed descriptive statistics,article co-citations,and keyword co-occurrence to identify key bibliometric indicators,themes,and trends.The findings reveal a surge in research activity related to blockchain and CF,emphasizing initial cryptocurrency offerings,financial technology(Fintech),and the role of blockchain in improving transactional efficiency,disintermediation,and venture capital CF.Keyword co-occurrence analysis reveals diverse research themes,including smart contracts,fundraising campaigns,sustainable entrepreneurship,and Islamic Fintech.Based on the findings of this analysis,several implications and directions for further investigation are highlighted.To the best of our knowledge,this is the first attempt to analyze the intersection of blockchain technology and CF using scientometric techniques systematically.展开更多
This review synthesizes 48 academic studies on Initial Coin Offerings(ICOs)from 2018 to 2023,employing bibliometric and content analyses to illuminate their complexities and innovation in entrepreneurial finance.It id...This review synthesizes 48 academic studies on Initial Coin Offerings(ICOs)from 2018 to 2023,employing bibliometric and content analyses to illuminate their complexities and innovation in entrepreneurial finance.It identifies four key themes:(1)regulatory intricacies,market transformation,and strategic implications for emerging ventures;(2)the opportunities and challenges presented,and key factors influencing the success of ICOs;(3)ICOs and entrepreneurial finance;and finally,(4)review of reviews.By examining the intersection of legal frameworks,disruptive potential,and stakeholder challenges,this interdisciplinary perspective captures the essence of ICOs and charts a course for future inquiry.It serves as a pivotal reference for researchers,practitioners,and regulators to understand the multifaceted ICO landscape and its implications for the future of finance.展开更多
The imperative pursuit of elevated energy density in lithium primary coin cells(LPCCs)necessitates strategic architectural optimization to align with evolving market demands.A predominant approach involves the systema...The imperative pursuit of elevated energy density in lithium primary coin cells(LPCCs)necessitates strategic architectural optimization to align with evolving market demands.A predominant approach involves the systematic replacement of metallic structural support components(MSSCs)to minimize non-active constituent ratios,contingent upon maintaining robust interfacial contact integrity among electrodes,separators,and battery shells.Herein,we present a novel LPCC configuration employing solvent-free processed ultra-thick fluorinated carbon cathode(UCFxC)to achieve complete MSSCs elimination.The engineered UCFxC demonstrates exceptional areal capacity metrics(249.45 mg cm^(-2),215.77 m Ah cm^(-2)),enabling a 27.8% mass reduction compared with conventional laboratoryassembled coin cell while achieving 941.5% energy density enhancement through optimized electrode conductivity.Notably,single-walled carbon nanotube(SWCNT)-modified UCFxC architectures exhibited superior performance with energy exceeding 1.0 Wh at 50℃.This architectural paradigm provides valuable insights for developing next-generation high-energy-density LPCC systems,with practical implications for advancing miniaturized power source technologies.展开更多
A capacity increase is often observed in the early stage of Li-ion battery cycling.This study explores the phenomena involved in the capacity increase from the full cell,electrodes,and materials perspective through a ...A capacity increase is often observed in the early stage of Li-ion battery cycling.This study explores the phenomena involved in the capacity increase from the full cell,electrodes,and materials perspective through a combination of non-destructive diagnostic methods in a full cell and post-mortem analysis in a coin cell.The results show an increase of 1%initial capacity for the battery aged at 100%depth of discharge(DOD)and 45℃.Furthermore,large DODs or high temperatures accelerate the capacity increase.From the incremental capacity and differential voltage(IC-DV)analysis,we concluded that the increased capacity in a full cell originates from the graphite anode.Furthermore,graphite/Li coin cells show an increased capacity for larger DODs and a decreased capacity for lower DODs,thus in agreement with the full cell results.Post-mortem analysis results show that a larger DOD enlarges the graphite dspace and separates the graphite layer structure,facilitating the Li+diffusion,hence increasing the battery capacity.展开更多
Foreign body ingestion is a common emergency situation in children with one or a few objects having been ingested. Here we report our experience using endo-scopic retrieval in a female centenarian with dyspnea and for...Foreign body ingestion is a common emergency situation in children with one or a few objects having been ingested. Here we report our experience using endo-scopic retrieval in a female centenarian with dyspnea and foreign bodies in the esophagus. She attempted suicide by swallowing 26 coins and two other foreign bodies. A gastroscope was used to remove all foreign bodies in the lower esophagus. In total, 26 coins, one ferrous ring and one cylindrical plastic object were retrieved. To our knowledge, this is the first clinical report on retrieval of so many foreign bodies in a single case.展开更多
Various adaptive designs have been proposed and applied to clinical trials, bio assay, psychophysics, etc.Adaptive designs are also useful in high cost engineering trials.More and more people have been paying attentio...Various adaptive designs have been proposed and applied to clinical trials, bio assay, psychophysics, etc.Adaptive designs are also useful in high cost engineering trials.More and more people have been paying attention to these design methods. This paper introduces several broad families of designs, such as the play-the-winner rule, randomized play-the-winner rule and its generalization to the multi-arm case, doubly biased coin adaptive design, Markov chain model.展开更多
Treated FeS2 samples were prepared by natural FeS2 samples which were ground first, heated in nitrogen and then washed in acid. The levels of impurity elements, primarily present as metallic oxides and sulfides, are h...Treated FeS2 samples were prepared by natural FeS2 samples which were ground first, heated in nitrogen and then washed in acid. The levels of impurity elements, primarily present as metallic oxides and sulfides, are higher in the natural FeS2 than those in the treated sample. Scanning electron microscopy shows that the grain sizes of treated FeS2, particles are smaller than those of natural FeS2 particles. The electrochemical performance of Li/treated FeS2 cells is attributed to the smaller grain sizes and higher purity of treated FeS2 particles in comparison to the natural FeS2 sample.展开更多
Objective： The aim of this study was to determine an optimal slice thickness that was efficient in revealing Iobulation of malignant solitary pulmonary nodules （SPNs） on multi-slice spiral computed tomography （MSC...Objective： The aim of this study was to determine an optimal slice thickness that was efficient in revealing Iobulation of malignant solitary pulmonary nodules （SPNs） on multi-slice spiral computed tomography （MSCT） images preliminarily. Methods： Fifty patients with malignant SPNs （diameter -〈 3 cm） underwent multidetector-row computed tomography of the chest in a single-breath-hold technique. The raw data were acquired with a collimation of 0.625 mm. Three sets of contiguous images were reconstructed with 1-, 2-, and 5-ram slice thickness, respectively. The Iobulation sign of SPNs on the computed tomography （CT） images presented in 1-, 2-, and 5-ram slice thickness was compared. Using the 1-mm sections as the gold standard, an optimal slice thickness in revealing Iobulation sign of SPNs was determined. Results： The 1-mm-thick images CT revealed 98 Iobulations （25 with chord distance 〈 1 ram; 30 with chord distance 1-2 ram; 43 with chord distance 〉 2 mm） of 45 malignant SPNs. 18 Iobulations with chord distance 〈 1 mm presented in 2-mm-thick sections were as same as those in I-ram-thick sections. Statistically significant difference in Iobulations number was found between that revealed in 2-ram-thick images and that in I-ram-thick images （P = 0.023 〈 0.05）. 16 Iobulations with chord distance 〈 1 mm presented in 5-mm-thick sections were as same as that in I-ram-thick sections. There was statistically significant difference in Iobulations number between that revealed in 5-mm-thick images and that in I-ram-thick images （P = 0.004 〈 0.05）. The 24 Iobulations with chord distance 1-2 mm presented in 2-ram-thick sections were as same as that in 1-mm-thick sections. No statistically significant difference in Iobulations number were found between that revealed in 2-mm-thick images and that in 1-mm-thick images （P = 0.261 〉 0.05）. 13 Iobulations with chord distance 1-2 mm presented in 5-ram-thick sections were as same as that in 1- mm-thick sections. There was statistically significant difference in Iobulations number between that revealed in 5-ram-thick images and that in I-ram-thick images （P = 0.003 〈 0.05）. 40 Iobulations with chord distance 〉 2 mm presented in 2-ram-thick sections were as same as that in I-ram-thick sections. No statistically significant difference in Iobulations number was found between that revealed in 2-ram-thick images and that in I-ram-thick images （P = 0.631 〉 0.05）. 36 Iobulations with chord distance 〉 2 mm presented in 5-mm-thick sections were as same as that in I-ram-thick sections. There was no statistically significant difference in Iobulations number between that revealed in 5-ram-thick images and that in I-ram-thick images （P = 0.264 〉 0.05）. Conclusion： It is suggested that the use of 1-mm slice thickness is suitable in revealing Iobulations with chord distance 〈 1 ram. A 2-mm slice thickness is suggested to be used in revealing Iobulafions with chord distance 1-2 mm and 5-mm slice thickness to be used in revealing Iobulations with chord distance 〉 2 mm.展开更多
In natural environment, tarnish was observed on the surface of historic and contemporary gold coins in several countries. Few years after the emergence of panda gold coins, several red spots were appeared on the surfa...In natural environment, tarnish was observed on the surface of historic and contemporary gold coins in several countries. Few years after the emergence of panda gold coins, several red spots were appeared on the surface. To identify the stains and to examine the spots, optical microscope （OM）, scanning electron microscope （SEM）, electron microprobe analysis （EMPA）, X-ray photoelectron spectroscopy （XPS）, and X-ray diffraction （XRD） were used. It was found by microscopic observation that the stain has a dark blue central area surrounded by a large area with a nuance of colors from brown to red. Red spots usually contain holes in the center, which are distributed along the forging stress zones formed in the struck process. From the surface analyses using EMPA, sulfur and silver are detected besides gold, and the contents of Ag and S at the tarnish part are higher than those at the other part. Furthermore, distributions of Ag and S are correlated with the morphology of stains. XPS shows that components of stains are Ag2S and Ag2SO4 and the former is much predominant. These results are confirmed using XRD analysis. Accelerated tarnish test of gold in an atmosphere containing sulfur compound proves that the similar phenomenon appears when a small amount of silver is present on the surface of gold. It can be concluded that the occurrence of tarnish stains is caused by the presence of Ag and S.展开更多
A symmetric all-organic non-aqueous redox flow-type battery was investigated employing the neutral small molecule radical 3-phenyl-1,5-di-p-tolylverdazyl,which can be reversibly oxidized and reduced in one-electron pr...A symmetric all-organic non-aqueous redox flow-type battery was investigated employing the neutral small molecule radical 3-phenyl-1,5-di-p-tolylverdazyl,which can be reversibly oxidized and reduced in one-electron processes,as the sole charge storage material.Cyclic voltammetry of the verdazyl radical in 0.5 M tetrabutylammonium hexa fluoro phosphate(TBAPF6)in acetonitrile revealed redox couples at-0.17 V and-1.15 V vs.Ag+/Ag,leading to a theoretical cell voltage of 0.98 V.From the dependence of peak currents on the square root of the scan rate,diffusion coefficients on the order of 4 x 10 6 cm2 s-1 were demonstrated.Cycling performance was assessed in a static cell employing a Tokoyuma AHA anion exchange membrane,with 0.04 M verdazyl as catholyte and anolyte in 0.5 M TBAPF6 in acetonitrile at a current density of 0.12 mA cm-2.Although coulombic efficiencies were good(94%-97%)throughout the experiment,the capacity faded gradually from high initial values of 93%of the theoretical discharge capacity to 35%by the 50th cycle.Voltage and energy efficiencies were 68%and 65%,respectively.Postcycling analysis by cyclic voltammetry revealed that decomposition of the active material with cycling is a leading cause of cell degradation.展开更多
Twenty Yongzheng copper coins were fast dating by X-ray energy dispersive spectrometer with scanning electron microscope(SEM-EDS)according to official ingredient.The 20 coins were classified in two groups according to...Twenty Yongzheng copper coins were fast dating by X-ray energy dispersive spectrometer with scanning electron microscope(SEM-EDS)according to official ingredient.The 20 coins were classified in two groups according to the results.Group 1 represents the coins minted before AD 1728 and group 2 represents the coins minted after AD 1728.At concentration range(0.00%–5.13%),the distribution of lead is not homogeneous in the coins,and the largest diameter of lead inclusion is less than 15μm.The official fineness degrade is supported.展开更多
Recent literature has addressed initial coin offering(ICO)projects,which are an innovative form of venture financing through cryptocurrencies using blockchain technology.Many features of ICOs remain unexplored,leaving...Recent literature has addressed initial coin offering(ICO)projects,which are an innovative form of venture financing through cryptocurrencies using blockchain technology.Many features of ICOs remain unexplored,leaving much room for additional research,including the success factors of ICO projects.We investigate the success of ICO projects,with our main purpose being to identify factors that influence a project’s outcome.Following a literature review,from which several potential variables were collected,we used a database comprising 428 ICO projects in the banking/financial sector to regress several econometric models.We confirmed the impacts of several variables and obtained particularly valuable results concerning project and campaign variables.We confirmed the importance of a well-structured and informative white-paper.The proximity to certain markets with high availability of financial and human capital is also an important determinant of the success of an ICO.We also confirm the strong dependency on cryptocurrency and the impact of cryptocurrency valuations on the success of a project.Furthermore,we confirm the importance of social media in ICO projects,as well as the importance of human capital characteristics.Our research contributes to the ICO literature by capturing most of the success factors previously identified and testing their impacts based on a large database.The current research contributes to the building of systems theory and signaling theory by adapting their frameworks to the ICO environment.Our results are also important for regulators,as ICOs are mainly unregulated and have vast future potential,and for investors,who can benefit from our analysis and use it in their due diligence.展开更多
Current minimization programs do not permit full control over different aspects of minimization algorithm such as distance or probability measures and may not allow for unequal allocation ratios. This article describe...Current minimization programs do not permit full control over different aspects of minimization algorithm such as distance or probability measures and may not allow for unequal allocation ratios. This article describes the implementation of “MinimPy” an open-source minimization program in Python programming language, which provides full customizetion of minimization features. MinimPy supports naive and biased coin minimization together with various new and classic distance measures. Data syncing is provided to facilitate minimization of multicenter trial over the network. MinimPy can easily be modified to fit special needs of clinical trials and in particular change it to a pure web application, though it currently supports network syncing of data in multi-center trials using network repositories.展开更多
文摘Blockchain technology and crowdfunding(CF)have emerged as disruptive forces in the finance and entrepreneurship landscape,potentially transforming traditional modes of capital raising and investment.This study investigates the intersection of blockchain technology and CF to provide a comprehensive overview of the current state of research through a systematic literature review and bibliometric analysis.By examining 219 publications sourced from Scopus,this study employed descriptive statistics,article co-citations,and keyword co-occurrence to identify key bibliometric indicators,themes,and trends.The findings reveal a surge in research activity related to blockchain and CF,emphasizing initial cryptocurrency offerings,financial technology(Fintech),and the role of blockchain in improving transactional efficiency,disintermediation,and venture capital CF.Keyword co-occurrence analysis reveals diverse research themes,including smart contracts,fundraising campaigns,sustainable entrepreneurship,and Islamic Fintech.Based on the findings of this analysis,several implications and directions for further investigation are highlighted.To the best of our knowledge,this is the first attempt to analyze the intersection of blockchain technology and CF using scientometric techniques systematically.
文摘This review synthesizes 48 academic studies on Initial Coin Offerings(ICOs)from 2018 to 2023,employing bibliometric and content analyses to illuminate their complexities and innovation in entrepreneurial finance.It identifies four key themes:(1)regulatory intricacies,market transformation,and strategic implications for emerging ventures;(2)the opportunities and challenges presented,and key factors influencing the success of ICOs;(3)ICOs and entrepreneurial finance;and finally,(4)review of reviews.By examining the intersection of legal frameworks,disruptive potential,and stakeholder challenges,this interdisciplinary perspective captures the essence of ICOs and charts a course for future inquiry.It serves as a pivotal reference for researchers,practitioners,and regulators to understand the multifaceted ICO landscape and its implications for the future of finance.
基金the financial support from the National Natural Science Foundation of China,Grant Nos.52307249the Natural Science Foundation of Shanghai Province,Nos.23ZR1465900+2 种基金the Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission,Nos.23CGA25the Fundamental Research Funds for the Central Universities at Tongji University,Nos.PA2022000668/22120220426the Nanchang Automotive Institute of Intelligence&New Energy of Tongji University,Nos.TPD-TC202211-02。
文摘The imperative pursuit of elevated energy density in lithium primary coin cells(LPCCs)necessitates strategic architectural optimization to align with evolving market demands.A predominant approach involves the systematic replacement of metallic structural support components(MSSCs)to minimize non-active constituent ratios,contingent upon maintaining robust interfacial contact integrity among electrodes,separators,and battery shells.Herein,we present a novel LPCC configuration employing solvent-free processed ultra-thick fluorinated carbon cathode(UCFxC)to achieve complete MSSCs elimination.The engineered UCFxC demonstrates exceptional areal capacity metrics(249.45 mg cm^(-2),215.77 m Ah cm^(-2)),enabling a 27.8% mass reduction compared with conventional laboratoryassembled coin cell while achieving 941.5% energy density enhancement through optimized electrode conductivity.Notably,single-walled carbon nanotube(SWCNT)-modified UCFxC architectures exhibited superior performance with energy exceeding 1.0 Wh at 50℃.This architectural paradigm provides valuable insights for developing next-generation high-energy-density LPCC systems,with practical implications for advancing miniaturized power source technologies.
基金supported by a grant from the China Scholarship Council(202006370035 and 202006220024)supported by the National Natural Science Foundation of China(52107229)。
文摘A capacity increase is often observed in the early stage of Li-ion battery cycling.This study explores the phenomena involved in the capacity increase from the full cell,electrodes,and materials perspective through a combination of non-destructive diagnostic methods in a full cell and post-mortem analysis in a coin cell.The results show an increase of 1%initial capacity for the battery aged at 100%depth of discharge(DOD)and 45℃.Furthermore,large DODs or high temperatures accelerate the capacity increase.From the incremental capacity and differential voltage(IC-DV)analysis,we concluded that the increased capacity in a full cell originates from the graphite anode.Furthermore,graphite/Li coin cells show an increased capacity for larger DODs and a decreased capacity for lower DODs,thus in agreement with the full cell results.Post-mortem analysis results show that a larger DOD enlarges the graphite dspace and separates the graphite layer structure,facilitating the Li+diffusion,hence increasing the battery capacity.
文摘Foreign body ingestion is a common emergency situation in children with one or a few objects having been ingested. Here we report our experience using endo-scopic retrieval in a female centenarian with dyspnea and foreign bodies in the esophagus. She attempted suicide by swallowing 26 coins and two other foreign bodies. A gastroscope was used to remove all foreign bodies in the lower esophagus. In total, 26 coins, one ferrous ring and one cylindrical plastic object were retrieved. To our knowledge, this is the first clinical report on retrieval of so many foreign bodies in a single case.
文摘Various adaptive designs have been proposed and applied to clinical trials, bio assay, psychophysics, etc.Adaptive designs are also useful in high cost engineering trials.More and more people have been paying attention to these design methods. This paper introduces several broad families of designs, such as the play-the-winner rule, randomized play-the-winner rule and its generalization to the multi-arm case, doubly biased coin adaptive design, Markov chain model.
基金SUPPORTED BY NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA( NO. 20273047)DOCTOR FOUNDATION OF MINISTRY OF EDUCATION ( NO. 20020056045).
文摘Treated FeS2 samples were prepared by natural FeS2 samples which were ground first, heated in nitrogen and then washed in acid. The levels of impurity elements, primarily present as metallic oxides and sulfides, are higher in the natural FeS2 than those in the treated sample. Scanning electron microscopy shows that the grain sizes of treated FeS2, particles are smaller than those of natural FeS2 particles. The electrochemical performance of Li/treated FeS2 cells is attributed to the smaller grain sizes and higher purity of treated FeS2 particles in comparison to the natural FeS2 sample.
文摘Objective： The aim of this study was to determine an optimal slice thickness that was efficient in revealing Iobulation of malignant solitary pulmonary nodules （SPNs） on multi-slice spiral computed tomography （MSCT） images preliminarily. Methods： Fifty patients with malignant SPNs （diameter -〈 3 cm） underwent multidetector-row computed tomography of the chest in a single-breath-hold technique. The raw data were acquired with a collimation of 0.625 mm. Three sets of contiguous images were reconstructed with 1-, 2-, and 5-ram slice thickness, respectively. The Iobulation sign of SPNs on the computed tomography （CT） images presented in 1-, 2-, and 5-ram slice thickness was compared. Using the 1-mm sections as the gold standard, an optimal slice thickness in revealing Iobulation sign of SPNs was determined. Results： The 1-mm-thick images CT revealed 98 Iobulations （25 with chord distance 〈 1 ram; 30 with chord distance 1-2 ram; 43 with chord distance 〉 2 mm） of 45 malignant SPNs. 18 Iobulations with chord distance 〈 1 mm presented in 2-mm-thick sections were as same as those in I-ram-thick sections. Statistically significant difference in Iobulations number was found between that revealed in 2-ram-thick images and that in I-ram-thick images （P = 0.023 〈 0.05）. 16 Iobulations with chord distance 〈 1 mm presented in 5-mm-thick sections were as same as that in I-ram-thick sections. There was statistically significant difference in Iobulations number between that revealed in 5-mm-thick images and that in I-ram-thick images （P = 0.004 〈 0.05）. The 24 Iobulations with chord distance 1-2 mm presented in 2-ram-thick sections were as same as that in 1-mm-thick sections. No statistically significant difference in Iobulations number were found between that revealed in 2-mm-thick images and that in 1-mm-thick images （P = 0.261 〉 0.05）. 13 Iobulations with chord distance 1-2 mm presented in 5-ram-thick sections were as same as that in 1- mm-thick sections. There was statistically significant difference in Iobulations number between that revealed in 5-ram-thick images and that in I-ram-thick images （P = 0.003 〈 0.05）. 40 Iobulations with chord distance 〉 2 mm presented in 2-ram-thick sections were as same as that in I-ram-thick sections. No statistically significant difference in Iobulations number was found between that revealed in 2-ram-thick images and that in I-ram-thick images （P = 0.631 〉 0.05）. 36 Iobulations with chord distance 〉 2 mm presented in 5-mm-thick sections were as same as that in I-ram-thick sections. There was no statistically significant difference in Iobulations number between that revealed in 5-ram-thick images and that in I-ram-thick images （P = 0.264 〉 0.05）. Conclusion： It is suggested that the use of 1-mm slice thickness is suitable in revealing Iobulations with chord distance 〈 1 ram. A 2-mm slice thickness is suggested to be used in revealing Iobulafions with chord distance 1-2 mm and 5-mm slice thickness to be used in revealing Iobulations with chord distance 〉 2 mm.
文摘In natural environment, tarnish was observed on the surface of historic and contemporary gold coins in several countries. Few years after the emergence of panda gold coins, several red spots were appeared on the surface. To identify the stains and to examine the spots, optical microscope （OM）, scanning electron microscope （SEM）, electron microprobe analysis （EMPA）, X-ray photoelectron spectroscopy （XPS）, and X-ray diffraction （XRD） were used. It was found by microscopic observation that the stain has a dark blue central area surrounded by a large area with a nuance of colors from brown to red. Red spots usually contain holes in the center, which are distributed along the forging stress zones formed in the struck process. From the surface analyses using EMPA, sulfur and silver are detected besides gold, and the contents of Ag and S at the tarnish part are higher than those at the other part. Furthermore, distributions of Ag and S are correlated with the morphology of stains. XPS shows that components of stains are Ag2S and Ag2SO4 and the former is much predominant. These results are confirmed using XRD analysis. Accelerated tarnish test of gold in an atmosphere containing sulfur compound proves that the similar phenomenon appears when a small amount of silver is present on the surface of gold. It can be concluded that the occurrence of tarnish stains is caused by the presence of Ag and S.
基金supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada (C. A. D.: DG, 04279 J. B. G.: DG, 435675 and S. M. B.: CGS D scholarship)+1 种基金support form the Canada Foundation for Innovation (CFI) the New Brunswick Innovation Foundation (NBIF)the University of New Brunswick. J. B. G. would like to thank the University of Western Ontario for support
文摘A symmetric all-organic non-aqueous redox flow-type battery was investigated employing the neutral small molecule radical 3-phenyl-1,5-di-p-tolylverdazyl,which can be reversibly oxidized and reduced in one-electron processes,as the sole charge storage material.Cyclic voltammetry of the verdazyl radical in 0.5 M tetrabutylammonium hexa fluoro phosphate(TBAPF6)in acetonitrile revealed redox couples at-0.17 V and-1.15 V vs.Ag+/Ag,leading to a theoretical cell voltage of 0.98 V.From the dependence of peak currents on the square root of the scan rate,diffusion coefficients on the order of 4 x 10 6 cm2 s-1 were demonstrated.Cycling performance was assessed in a static cell employing a Tokoyuma AHA anion exchange membrane,with 0.04 M verdazyl as catholyte and anolyte in 0.5 M TBAPF6 in acetonitrile at a current density of 0.12 mA cm-2.Although coulombic efficiencies were good(94%-97%)throughout the experiment,the capacity faded gradually from high initial values of 93%of the theoretical discharge capacity to 35%by the 50th cycle.Voltage and energy efficiencies were 68%and 65%,respectively.Postcycling analysis by cyclic voltammetry revealed that decomposition of the active material with cycling is a leading cause of cell degradation.
基金Supported by the Project of Instrument Upgraded of Ministry of Science and Technology of China
文摘Twenty Yongzheng copper coins were fast dating by X-ray energy dispersive spectrometer with scanning electron microscope(SEM-EDS)according to official ingredient.The 20 coins were classified in two groups according to the results.Group 1 represents the coins minted before AD 1728 and group 2 represents the coins minted after AD 1728.At concentration range(0.00%–5.13%),the distribution of lead is not homogeneous in the coins,and the largest diameter of lead inclusion is less than 15μm.The official fineness degrade is supported.
基金supported by Fundação para a Ciência e a Tecnologia,grant UIDB/00315/2020.
文摘Recent literature has addressed initial coin offering(ICO)projects,which are an innovative form of venture financing through cryptocurrencies using blockchain technology.Many features of ICOs remain unexplored,leaving much room for additional research,including the success factors of ICO projects.We investigate the success of ICO projects,with our main purpose being to identify factors that influence a project’s outcome.Following a literature review,from which several potential variables were collected,we used a database comprising 428 ICO projects in the banking/financial sector to regress several econometric models.We confirmed the impacts of several variables and obtained particularly valuable results concerning project and campaign variables.We confirmed the importance of a well-structured and informative white-paper.The proximity to certain markets with high availability of financial and human capital is also an important determinant of the success of an ICO.We also confirm the strong dependency on cryptocurrency and the impact of cryptocurrency valuations on the success of a project.Furthermore,we confirm the importance of social media in ICO projects,as well as the importance of human capital characteristics.Our research contributes to the ICO literature by capturing most of the success factors previously identified and testing their impacts based on a large database.The current research contributes to the building of systems theory and signaling theory by adapting their frameworks to the ICO environment.Our results are also important for regulators,as ICOs are mainly unregulated and have vast future potential,and for investors,who can benefit from our analysis and use it in their due diligence.
文摘Current minimization programs do not permit full control over different aspects of minimization algorithm such as distance or probability measures and may not allow for unequal allocation ratios. This article describes the implementation of “MinimPy” an open-source minimization program in Python programming language, which provides full customizetion of minimization features. MinimPy supports naive and biased coin minimization together with various new and classic distance measures. Data syncing is provided to facilitate minimization of multicenter trial over the network. MinimPy can easily be modified to fit special needs of clinical trials and in particular change it to a pure web application, though it currently supports network syncing of data in multi-center trials using network repositories.
