This study conducts a systematic literature review(SLR)of blockchain consensus mechanisms,an essential protocols that maintain the integrity,reliability,and decentralization of distributed ledger networks.The aim is t...This study conducts a systematic literature review(SLR)of blockchain consensus mechanisms,an essential protocols that maintain the integrity,reliability,and decentralization of distributed ledger networks.The aim is to comprehensively investigate prominent mechanisms’security features and vulnerabilities,emphasizing their security considerations,applications,challenges,and future directions.The existing literature offers valuable insights into various consensus mechanisms’strengths,limitations,and security vulnerabilities and their real-world applications.However,there remains a gap in synthesizing and analyzing this knowledge systematically.Addressing this gap would facilitate a structured approach to understanding consensus mechanisms’security and vulnerabilities comprehensively.The study adheres to Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines and computer science standards and reviewed 3749 research papers from 2016 to 2024,excluding grey literature,resulting in 290 articles for descriptive analysis.The research highlights an increased focus on blockchain consensus security,energy efficiency,and hybrid mechanisms within 60%of research papers post-2019,identifying gaps in scalability,privacy,and interoperability for future exploration.By synthesizing the existing research and identifying the key trends,this SLR contributes to advancing the understanding of blockchain consensus mechanisms’security and guiding future research and structured innovation in blockchain systems and applications.展开更多
In this study,single-phase NbTiZr and NbTiZr(MoTa)_(0.1) medium-entropy alloys(MEAs)were investigated for their use in biomedical implants.The alloys were prepared by arc melting,and were then cold-rolled,annealed,and...In this study,single-phase NbTiZr and NbTiZr(MoTa)_(0.1) medium-entropy alloys(MEAs)were investigated for their use in biomedical implants.The alloys were prepared by arc melting,and were then cold-rolled,annealed,and characterized in terms of phase analysis,mechanical properties,fractography,and wear resistance.Both alloys showed a single body-centered cubic phase with superior mechanical,and tribological properties compared to commercially available biomedical alloys.Mo and Ta-containing MEAs showed higher tensile yield strength(1060±18 MPa)and higher tensile ductility(~20%),thus overcoming the strength-ductility trade-off with no signs of transformation-induced plasticity,twinning,or precipitation.The generalized stacking fault energy(GSFE)calculations on the{112}<111>slip system by the first-principles calculations based on density functional theory showed that the addition of less than0.2 molar fraction of Mo and Ta lowers the GSFE curves.This behavior posits the increase in ductility of the alloy by facilitating slips although strength is also increased by solid solution strengthening.The wear resistance of both alloys against hardened steel surfaces was superior to that of commercial biomedical alloys.Thus,we concluded that NbTiZr(MoTa)_(0.1)MEA with good tensile ductility is a potential candidate for biomedical implants.展开更多
Chemical randomness and the associated energy fluctuation are essential features of multi-principal ele-ment alloys(MPEAs).Due to these features,nanoscale stacking fault energy(SFE)fluctuation is a natural and indepen...Chemical randomness and the associated energy fluctuation are essential features of multi-principal ele-ment alloys(MPEAs).Due to these features,nanoscale stacking fault energy(SFE)fluctuation is a natural and independent contribution to strengthening MPEAs.However,existing models for conventional alloys(i.e.,alloys with one principal element)cannot be applied to MPEAs.The extreme values of SFEs required by such models are unknown for MPEAs,which need to calculate the nanoscale volume relevant to the SFE fluctuation.In the present work,we developed an analytic model to evaluate the strengthening ef-fect through the SFE fluctuation,profuse in MPEAs.The model has no adjustable parameters,and all parameters can be determined from experiments and ab initio calculations.This model explains available experimental observations and provides insightful guidance for designing new MPEAs based on the SFE fluctuation.It generally applies to MPEAs in random states and with chemical short-range order.展开更多
先来看摘自一篇英语散文中的段落：地点哈瓦那,一个匈牙利人与倒卖雪茄的黑人烟贩子讨价还价。＂You’re crazy!＂cries the Hungarian in slightly accented English,taking one of the boxes from the trunk and waving it in Howard ...先来看摘自一篇英语散文中的段落：地点哈瓦那,一个匈牙利人与倒卖雪茄的黑人烟贩子讨价还价。＂You’re crazy!＂cries the Hungarian in slightly accented English,taking one of the boxes from the trunk and waving it in Howard Bingham’s face.＂These are Cohiba Esplendidos!The best in the world!You will pay one thousand dollars for a box like this in the States.＂展开更多
In the blockchain,the consensus mechanism plays a key role in maintaining the security and legitimation of contents recorded in the blocks.Various blockchain consensus mechanisms have been proposed.However,there is no...In the blockchain,the consensus mechanism plays a key role in maintaining the security and legitimation of contents recorded in the blocks.Various blockchain consensus mechanisms have been proposed.However,there is no technical analysis and comparison as a guideline to determine which type of consensus mechanism should be adopted in a specific scenario/application.To this end,this work investigates three mainstream consensus mechanisms in the blockchain,namely,Proof of Work(PoW),Proof of Stake(PoS),and Direct Acyclic Graph(DAG),and identifies their performances in terms of the average time to generate a new block,the confirmation delay,the Transaction Per Second(TPS)and the confirmation failure probability.The results show that the consensus process is affected by both network resource(computation power/coin age,buffer size)and network load conditions.In addition,it shows that PoW and PoS are more sensitive to the change of network resource while DAG is more sensitive to network load conditions.展开更多
On February 19,2012,WalMart Stores,Inc.disclosed its additional investment in Yihaodian,a fast-growing electronic commerce website in China,making Walmart’s total ownership stake in Yihaodian to reach approximately 5...On February 19,2012,WalMart Stores,Inc.disclosed its additional investment in Yihaodian,a fast-growing electronic commerce website in China,making Walmart’s total ownership stake in Yihaodian to reach approximately 51%.It was Wal-Mart’s second investment for the purpose展开更多
This paper aims to discuss and analyze the distribution characteristics of the private placement among different regions and different industries by state-owned and private holding enterprises as well as the changed e...This paper aims to discuss and analyze the distribution characteristics of the private placement among different regions and different industries by state-owned and private holding enterprises as well as the changed earning capacities of the capital before and after the placement. Taking the private placement financing data of the listed companies during the period of 2006-2011 in China's A-share markets as the sample, this study adopts the panel data model to conduct a quantitative analysis of the industrial upgrading effect of the private placement by listed companies with different holding natures. The empirical results show that though the private placement by the state-owned and private holding enterprises has not significantly improved the Clark index in any region, the private placement by private holding companies has significantly improved the growth rate of the tertiary industry in the eastern region. While reducing the proportion of the tertiary industry in GDP in the central and western regions, it has also improved the growth rate of the secondary industry and its proportion in GDP in that region to a larger extent. Yet the private placement of state-owned enterprises has no significant effect on the industrial upgrading path in any region except that it helped to raise the proportion of the secondary industry in GDP a little in the eastern region.展开更多
An Ethereum blockchain based on proof of stake ( PoS) consensus mechanism is used to achieve the data sharing within the civil aviation service platform for both airport group management and passengers. Considering th...An Ethereum blockchain based on proof of stake ( PoS) consensus mechanism is used to achieve the data sharing within the civil aviation service platform for both airport group management and passengers. Considering the Gas consumption of Ethereum, the dynamic batch-service capacity constraint by the Block Gas Limit and the priority mechanism depending on the different Gas Price of transactions, M/ G/1 queuing theory with batch-service is used to construct the service model of transactions confirmation process in the proposed blockchain system, where the effects of transactions arrival rate, block capacity, service rate and number of nodes on the average confirmation time of transactions with different priority are analyzed, and eventually a performance analysis model of blockchain for civil aviation business data is proposed. The simulation results prove the usability and accuracy of the model, which can provide both theoretical basis for data sharing of civil aviation using Ethereum blockchain and the further optimization of transactions confirmation time.展开更多
E-commerce is becoming a focus for retailers and brand owners.China is expected to become the world’s largest retail market by 2018,though its retail’s growth rate is slowing,as revealed in a recent report by PwC.Ch...E-commerce is becoming a focus for retailers and brand owners.China is expected to become the world’s largest retail market by 2018,though its retail’s growth rate is slowing,as revealed in a recent report by PwC.China retail’s growth rate has fallen from a peak of 15.6%in 2009,yet China remains irresistible to global retail chains.China is still expected to achieve average annual retail volume growth of 8.7%in the next two years.展开更多
In October 2013,Chinese President Xi Jinping proposed to establish Asia Infrastructure Investment Bank during his meeting with Indonesia President Susilo.It is comprehensive and complex economic and political situatio...In October 2013,Chinese President Xi Jinping proposed to establish Asia Infrastructure Investment Bank during his meeting with Indonesia President Susilo.It is comprehensive and complex economic and political situations that helps to bring about the establishment of AⅡB.展开更多
AWRITER once comparedSino-foreign cultural ex- changes to a lengthybridge across the oceans of theworld.The Beijing CPAA Cultur- al Entertainment Company,esta- blished in the spring of this year,undoubtedly comes to m...AWRITER once comparedSino-foreign cultural ex- changes to a lengthybridge across the oceans of theworld.The Beijing CPAA Cultur- al Entertainment Company,esta- blished in the spring of this year,undoubtedly comes to many peo- ple’s minds when contemplatingthis remark.The Beijing CPAA Cultural En- tertainment Company is a subsidi- ary of the China Performing ArtsAgency,directly under the Ministryof Culture.It is a self-managed statefirm specializing in international ex-展开更多
Between November 24 and 25,2015,the 4th Summit of China-Central-East Europe Leaders’Meeting was held in Suzhou,Jiangsu Province,which issued the Suzhou Guidelines for Cooperation between China and Central and Eastern...Between November 24 and 25,2015,the 4th Summit of China-Central-East Europe Leaders’Meeting was held in Suzhou,Jiangsu Province,which issued the Suzhou Guidelines for Cooperation between China and Central and Eastern European Countries and the Medium-Term Agenda for Cooperation between China and Central and Eastern European Countries framing the develop-展开更多
一、What 有时相当于 just as。1.Poultry is for the cook what canvas is for the painter厨师离不了家禽正如画家离不了画布一样。2.Leaves are to the plant what lungs are to the animal叶之于植物犹如肺之于动物。二、what 与 wi...一、What 有时相当于 just as。1.Poultry is for the cook what canvas is for the painter厨师离不了家禽正如画家离不了画布一样。2.Leaves are to the plant what lungs are to the animal叶之于植物犹如肺之于动物。二、what 与 with 连用表示原因,与 by 连用表示方法或手段;展开更多
[问][159]如何使用 who 与 whoever?[答]who 与 whoever 均可用作连接代词,引导主语从句和宾语从句,whoever 是 who 的强势形式,由 who+ever 构成。如:1.Who robbed the bark is not clear.2.Whoever breaks the law will be punished....[问][159]如何使用 who 与 whoever?[答]who 与 whoever 均可用作连接代词,引导主语从句和宾语从句,whoever 是 who 的强势形式,由 who+ever 构成。如:1.Who robbed the bark is not clear.2.Whoever breaks the law will be punished.例1中 who 引导的主语从句所指的是“谁抢劫了银行”这件事;而 whoever=anyone who,any per-展开更多
In the 21<sup>st</sup> Century, Food and Agricultural stakes are sinuously rushing in a difficult legible heading. Crossing a transitory phase period between Agriculture, Traditional, Urban and Modern, the...In the 21<sup>st</sup> Century, Food and Agricultural stakes are sinuously rushing in a difficult legible heading. Crossing a transitory phase period between Agriculture, Traditional, Urban and Modern, the affirmation of a conquering alimentary identity and Nationalist openings is confuse with an Extraordinary Demographic Period of human scale history. Millions of people are worried about the innovation of urban agriculture for food and health security. Food education at the confines of the world’s greatest stakes proves necessary, since the order oneself retreat combines with the passion of solidarity and social progress, advance in technology, facilitating our life at same time generating new threats for citizenship. In this Article, we propose another way of reading the heterogeneous world of yesterday, today and tomorrow. Not only for Historians but also by associating Scientific Relations of Social and Human Researchers. Such a step is necessary to endorse the word of reading, for comparism and review of an agriculture in full mutation. It also instigates by referring to History, Social force, Economic stakes and Diplomatic globalization food teste, intention and invention, which change with the everyday society. You will find out that analysis done in this article are sometime completely done events through original texts, assembled around the five fundamental notions: International Relations and Geopolitical Agriculture of yesterday;Yesterday Urban Economic Agriculture;Environmental and Food Climate Stakes, Science and Culture adapted to agriculture and food mutations.展开更多
According to Bloomberg on November 12, China Petrochemical Corp., Asia’s biggest ref iner, agreed to buy a 30 percent stake in Galp Energia SGPS SA (GALP)’s Brazilian unit, its second invest- ment in offshore oil fi...According to Bloomberg on November 12, China Petrochemical Corp., Asia’s biggest ref iner, agreed to buy a 30 percent stake in Galp Energia SGPS SA (GALP)’s Brazilian unit, its second invest- ment in offshore oil fields in Latin America’s largest economy in as many years.展开更多
基金funded by Universiti Teknologi PETRONAS and grants(YUTP-PRG:015PBC-011).
文摘This study conducts a systematic literature review(SLR)of blockchain consensus mechanisms,an essential protocols that maintain the integrity,reliability,and decentralization of distributed ledger networks.The aim is to comprehensively investigate prominent mechanisms’security features and vulnerabilities,emphasizing their security considerations,applications,challenges,and future directions.The existing literature offers valuable insights into various consensus mechanisms’strengths,limitations,and security vulnerabilities and their real-world applications.However,there remains a gap in synthesizing and analyzing this knowledge systematically.Addressing this gap would facilitate a structured approach to understanding consensus mechanisms’security and vulnerabilities comprehensively.The study adheres to Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines and computer science standards and reviewed 3749 research papers from 2016 to 2024,excluding grey literature,resulting in 290 articles for descriptive analysis.The research highlights an increased focus on blockchain consensus security,energy efficiency,and hybrid mechanisms within 60%of research papers post-2019,identifying gaps in scalability,privacy,and interoperability for future exploration.By synthesizing the existing research and identifying the key trends,this SLR contributes to advancing the understanding of blockchain consensus mechanisms’security and guiding future research and structured innovation in blockchain systems and applications.
基金supported by the National Research Foundation of Korea(NRF-2020R1A5A6017701,NRF-2121R1A2C2014025)。
文摘In this study,single-phase NbTiZr and NbTiZr(MoTa)_(0.1) medium-entropy alloys(MEAs)were investigated for their use in biomedical implants.The alloys were prepared by arc melting,and were then cold-rolled,annealed,and characterized in terms of phase analysis,mechanical properties,fractography,and wear resistance.Both alloys showed a single body-centered cubic phase with superior mechanical,and tribological properties compared to commercially available biomedical alloys.Mo and Ta-containing MEAs showed higher tensile yield strength(1060±18 MPa)and higher tensile ductility(~20%),thus overcoming the strength-ductility trade-off with no signs of transformation-induced plasticity,twinning,or precipitation.The generalized stacking fault energy(GSFE)calculations on the{112}<111>slip system by the first-principles calculations based on density functional theory showed that the addition of less than0.2 molar fraction of Mo and Ta lowers the GSFE curves.This behavior posits the increase in ductility of the alloy by facilitating slips although strength is also increased by solid solution strengthening.The wear resistance of both alloys against hardened steel surfaces was superior to that of commercial biomedical alloys.Thus,we concluded that NbTiZr(MoTa)_(0.1)MEA with good tensile ductility is a potential candidate for biomedical implants.
基金sponsored by the U.S.Department of En-ergy,Office of Science,Basic Energy Sciences,Materials Science and Engineering Divisionsupported by the Office of Science of the U.S.Department of Energy under Contract No.DE-AC05-00OR22725+2 种基金the supports from(1)the National Science Foundation(DMR-1611180 and 1809640)with program directors,Drs.J.Yang,G.Shifletthe US Army Research Office(W911NF-13-1-0438 and W911NF-19-2-0049)with program managers,Drs.M.P.Bakas,S.N.Math-audhuthe support of U.S.Na-tional Science Foundation under grant DMR-1804320.
文摘Chemical randomness and the associated energy fluctuation are essential features of multi-principal ele-ment alloys(MPEAs).Due to these features,nanoscale stacking fault energy(SFE)fluctuation is a natural and independent contribution to strengthening MPEAs.However,existing models for conventional alloys(i.e.,alloys with one principal element)cannot be applied to MPEAs.The extreme values of SFEs required by such models are unknown for MPEAs,which need to calculate the nanoscale volume relevant to the SFE fluctuation.In the present work,we developed an analytic model to evaluate the strengthening ef-fect through the SFE fluctuation,profuse in MPEAs.The model has no adjustable parameters,and all parameters can be determined from experiments and ab initio calculations.This model explains available experimental observations and provides insightful guidance for designing new MPEAs based on the SFE fluctuation.It generally applies to MPEAs in random states and with chemical short-range order.
文摘先来看摘自一篇英语散文中的段落：地点哈瓦那,一个匈牙利人与倒卖雪茄的黑人烟贩子讨价还价。＂You’re crazy!＂cries the Hungarian in slightly accented English,taking one of the boxes from the trunk and waving it in Howard Bingham’s face.＂These are Cohiba Esplendidos!The best in the world!You will pay one thousand dollars for a box like this in the States.＂
基金the National Natural Science Foundation of China under Grant 61701059,Grant 61941114,and Grant 61831002,in part by the Fundamental Research Funds for the Central Universities of New TeachersProject,in part by the Chongqing Technological Innovation and Application Development Projects under Grant cstc2019jscx-msxm1322,and in part by the Eighteentg Open Foundation of State Key Lab of Integrated Services Networks of Xidian University under Grant ISN20-05.
文摘In the blockchain,the consensus mechanism plays a key role in maintaining the security and legitimation of contents recorded in the blocks.Various blockchain consensus mechanisms have been proposed.However,there is no technical analysis and comparison as a guideline to determine which type of consensus mechanism should be adopted in a specific scenario/application.To this end,this work investigates three mainstream consensus mechanisms in the blockchain,namely,Proof of Work(PoW),Proof of Stake(PoS),and Direct Acyclic Graph(DAG),and identifies their performances in terms of the average time to generate a new block,the confirmation delay,the Transaction Per Second(TPS)and the confirmation failure probability.The results show that the consensus process is affected by both network resource(computation power/coin age,buffer size)and network load conditions.In addition,it shows that PoW and PoS are more sensitive to the change of network resource while DAG is more sensitive to network load conditions.
文摘On February 19,2012,WalMart Stores,Inc.disclosed its additional investment in Yihaodian,a fast-growing electronic commerce website in China,making Walmart’s total ownership stake in Yihaodian to reach approximately 51%.It was Wal-Mart’s second investment for the purpose
文摘This paper aims to discuss and analyze the distribution characteristics of the private placement among different regions and different industries by state-owned and private holding enterprises as well as the changed earning capacities of the capital before and after the placement. Taking the private placement financing data of the listed companies during the period of 2006-2011 in China's A-share markets as the sample, this study adopts the panel data model to conduct a quantitative analysis of the industrial upgrading effect of the private placement by listed companies with different holding natures. The empirical results show that though the private placement by the state-owned and private holding enterprises has not significantly improved the Clark index in any region, the private placement by private holding companies has significantly improved the growth rate of the tertiary industry in the eastern region. While reducing the proportion of the tertiary industry in GDP in the central and western regions, it has also improved the growth rate of the secondary industry and its proportion in GDP in that region to a larger extent. Yet the private placement of state-owned enterprises has no significant effect on the industrial upgrading path in any region except that it helped to raise the proportion of the secondary industry in GDP a little in the eastern region.
基金the Open Foundation of Key Laboratory of Airports Cluster Intelligent Operation(No.KLACIO201900006124)National Natural Science Foundation of China(No.61901011)+1 种基金Foundation of Beijing Municipal Commission of Education(No.KM202010005017,KM202110005021)Beijing Natural Science Foundation(No.L192002).
文摘An Ethereum blockchain based on proof of stake ( PoS) consensus mechanism is used to achieve the data sharing within the civil aviation service platform for both airport group management and passengers. Considering the Gas consumption of Ethereum, the dynamic batch-service capacity constraint by the Block Gas Limit and the priority mechanism depending on the different Gas Price of transactions, M/ G/1 queuing theory with batch-service is used to construct the service model of transactions confirmation process in the proposed blockchain system, where the effects of transactions arrival rate, block capacity, service rate and number of nodes on the average confirmation time of transactions with different priority are analyzed, and eventually a performance analysis model of blockchain for civil aviation business data is proposed. The simulation results prove the usability and accuracy of the model, which can provide both theoretical basis for data sharing of civil aviation using Ethereum blockchain and the further optimization of transactions confirmation time.
文摘E-commerce is becoming a focus for retailers and brand owners.China is expected to become the world’s largest retail market by 2018,though its retail’s growth rate is slowing,as revealed in a recent report by PwC.China retail’s growth rate has fallen from a peak of 15.6%in 2009,yet China remains irresistible to global retail chains.China is still expected to achieve average annual retail volume growth of 8.7%in the next two years.
文摘In October 2013,Chinese President Xi Jinping proposed to establish Asia Infrastructure Investment Bank during his meeting with Indonesia President Susilo.It is comprehensive and complex economic and political situations that helps to bring about the establishment of AⅡB.
文摘AWRITER once comparedSino-foreign cultural ex- changes to a lengthybridge across the oceans of theworld.The Beijing CPAA Cultur- al Entertainment Company,esta- blished in the spring of this year,undoubtedly comes to many peo- ple’s minds when contemplatingthis remark.The Beijing CPAA Cultural En- tertainment Company is a subsidi- ary of the China Performing ArtsAgency,directly under the Ministryof Culture.It is a self-managed statefirm specializing in international ex-
文摘Between November 24 and 25,2015,the 4th Summit of China-Central-East Europe Leaders’Meeting was held in Suzhou,Jiangsu Province,which issued the Suzhou Guidelines for Cooperation between China and Central and Eastern European Countries and the Medium-Term Agenda for Cooperation between China and Central and Eastern European Countries framing the develop-
文摘一、What 有时相当于 just as。1.Poultry is for the cook what canvas is for the painter厨师离不了家禽正如画家离不了画布一样。2.Leaves are to the plant what lungs are to the animal叶之于植物犹如肺之于动物。二、what 与 with 连用表示原因,与 by 连用表示方法或手段;
文摘[问][159]如何使用 who 与 whoever?[答]who 与 whoever 均可用作连接代词,引导主语从句和宾语从句,whoever 是 who 的强势形式,由 who+ever 构成。如:1.Who robbed the bark is not clear.2.Whoever breaks the law will be punished.例1中 who 引导的主语从句所指的是“谁抢劫了银行”这件事;而 whoever=anyone who,any per-
文摘In the 21<sup>st</sup> Century, Food and Agricultural stakes are sinuously rushing in a difficult legible heading. Crossing a transitory phase period between Agriculture, Traditional, Urban and Modern, the affirmation of a conquering alimentary identity and Nationalist openings is confuse with an Extraordinary Demographic Period of human scale history. Millions of people are worried about the innovation of urban agriculture for food and health security. Food education at the confines of the world’s greatest stakes proves necessary, since the order oneself retreat combines with the passion of solidarity and social progress, advance in technology, facilitating our life at same time generating new threats for citizenship. In this Article, we propose another way of reading the heterogeneous world of yesterday, today and tomorrow. Not only for Historians but also by associating Scientific Relations of Social and Human Researchers. Such a step is necessary to endorse the word of reading, for comparism and review of an agriculture in full mutation. It also instigates by referring to History, Social force, Economic stakes and Diplomatic globalization food teste, intention and invention, which change with the everyday society. You will find out that analysis done in this article are sometime completely done events through original texts, assembled around the five fundamental notions: International Relations and Geopolitical Agriculture of yesterday;Yesterday Urban Economic Agriculture;Environmental and Food Climate Stakes, Science and Culture adapted to agriculture and food mutations.
文摘According to Bloomberg on November 12, China Petrochemical Corp., Asia’s biggest ref iner, agreed to buy a 30 percent stake in Galp Energia SGPS SA (GALP)’s Brazilian unit, its second invest- ment in offshore oil fields in Latin America’s largest economy in as many years.
