Electrochemical CO_(2) reduction reaction(CO_(2) RR)exhibits remarkable potential in producing valuable chemicals with renewable energy.Operating CO_(2) RR in acidic media is beneficial to solve the issue of low carbo...Electrochemical CO_(2) reduction reaction(CO_(2) RR)exhibits remarkable potential in producing valuable chemicals with renewable energy.Operating CO_(2) RR in acidic media is beneficial to solve the issue of low carbon utilization brought by(bi)carbonate formation at the cathode.Suppressing the competing hydrogen evolution reaction and achieving stable CO_(2) RR performance remains challenging.Herein,we constructed a 3-dimensional Cu(3D-Cu)gas diffusion electrode(GDE)to achieve efficient C_(2)H_(4) production with a partial current density(j C_(2)H_(4))of over 470 mA cm^(2) and a Faradaic efficiency(FE C_(2)H_(4)) of 40%.With pause electrolysis,the decay rate of the j C_(2)H_(4) is only half that of the traditional constant electrolysis.The GDE after constant electrolysis was found to suffer from severe salt formation,leading to the decreased activity and poor stability.展开更多
In the college English classroom, pauses function to help students construct speech, promote mutual interaction and lay bare the problems to be looked into. They are critical for the Chinese students speaking English ...In the college English classroom, pauses function to help students construct speech, promote mutual interaction and lay bare the problems to be looked into. They are critical for the Chinese students speaking English by facilitating more appropriate and complex speech in a language they are not as skilled as in their mother tongue. They are also crucial for the teachers in reflecting the cognitive activities of the students, enabling the teachers to understand and track down the speaking trouble on the spot while suggesting places for improvement in their teaching in the future.展开更多
Issues related to the pause of global warming in the last decade are reviewed.It is indicated that:(1) The decade of 1999-2008 is still the warmest of the last 30 years,though the global temperature increment is near ...Issues related to the pause of global warming in the last decade are reviewed.It is indicated that:(1) The decade of 1999-2008 is still the warmest of the last 30 years,though the global temperature increment is near zero;(2) Natural factors such as volcanism,solar radiation,ENSO,and thermohaline circulation can have impact on the inter-annual and inter-decadal variability of global mean temperatures.However,it will not mask the global warming trend for a long time;(3) Temperatures of China continue to increase in 1999-2008 with an increment of 0.4-0.5℃per 10 years.展开更多
<正> Like most July days,it was hot. I stepped into a tiny ice-cream shop to cool off with a chocolate sundae. It was an old-time store, just recently restored—~* with white oak wood-work,little round tables an...<正> Like most July days,it was hot. I stepped into a tiny ice-cream shop to cool off with a chocolate sundae. It was an old-time store, just recently restored—~* with white oak wood-work,little round tables and curlicue chairs.As I entered, 1 caught a glimpse of a very old woman bentover a table near the door.~* Her back was so badly twisted展开更多
Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid...Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid Dynamics Technical Committee. Experiments were conducted in a low-speed wind tunnel at both a constant mean angle of attack and an oscillation amplitude with a reduced frequency ranging from 0.01 to 0.12. The desired stop angles of the airfoil were set to occur during the upstroke motion. The unsteady pressure distribution on the airfoil was measured for below, near, and beyond static stall conditions. Results showed that the reduced frequency and stop angle were the dominant contributors to the time lag in the flowfield. For stop angles in both belowand post-stall regions, the time for the flowfield to reach its steady state conditions, known as the time lag, decreased as the reduced frequency was increased. However, in the static-stall region and for a certain value of reduced frequency, a resonance phenomenon was observed, and a minimum time lag was achieved. The pressure distribution in this condition was shown to be highly influenced by this phenomenon.展开更多
五一期间，由LAVIE HOME策划的“遇见大师．遇见艺术，遇见家”跨界合作作品展．在上海久光百货2F中庭顺利落下帷幕。展览虽然只有短短一周．但却首度将芬兰设计师器皿品牌Iittala与日本服装设计师Issey Miyake（三宅一生）历时四年共...五一期间，由LAVIE HOME策划的“遇见大师．遇见艺术，遇见家”跨界合作作品展．在上海久光百货2F中庭顺利落下帷幕。展览虽然只有短短一周．但却首度将芬兰设计师器皿品牌Iittala与日本服装设计师Issey Miyake（三宅一生）历时四年共同打造的“Pause for harmony“家居系列集中展示在国人面前。跨品牌合作的”Pause for harmony”家居系列共有30件具有划时代意义的作品．展开更多
This paper concerns minimum-energy leader-following formation design and analysis problems of distributed multiagent systems(DMASs)subjected to randomly switching topologies and aperiodic communication pauses.The crit...This paper concerns minimum-energy leader-following formation design and analysis problems of distributed multiagent systems(DMASs)subjected to randomly switching topologies and aperiodic communication pauses.The critical feature of this paper is that the energy consumption during the formation control process is restricted by the minimum-energy constraint in the sense of the linear matrix inequality.Firstly,the leader-following formation control protocol is proposed based on the relative state information of neighboring agents,where the total energy consumption is considered.Then,minimum-energy leader-following formation design and analysis criteria are presented in the form of the linear matrix inequality,which can be checked by the generalized eigenvalue method.Especially,the value of the minimum-energy constraint is determined.An illustrative simulation is provided to show the effectiveness of the main results.展开更多
Speaking is a productive skill and it is acknowledged to be hard for learners to master.Certain elements related to phonetics in discourse analysis,which play a significant role in EFL teaching of speaking,seem to be ...Speaking is a productive skill and it is acknowledged to be hard for learners to master.Certain elements related to phonetics in discourse analysis,which play a significant role in EFL teaching of speaking,seem to be neglected.This paper analyses three of these elements:pause,intonation and tonic syllable,and their application in the teaching of speaking.展开更多
为帮助同学们复习、掌握go on这一短语,现将其主要用法归纳如下: 一、go on作“继续”解 We’ll leave the story for the time being,and go on tomorrow。这个故事我们就讲到这里,明天再继续。① go on doing sth.意为“继续做某事”...为帮助同学们复习、掌握go on这一短语,现将其主要用法归纳如下: 一、go on作“继续”解 We’ll leave the story for the time being,and go on tomorrow。这个故事我们就讲到这里,明天再继续。① go on doing sth.意为“继续做某事”,指不停地继续做同一事情,也可指暂停后的继续。总之,go on doing sth。是继续原来的动作。展开更多
歇后语是人们在生活实践中创造的一种特殊语言形式。它是人民大众喜闻乐见的一种俗语,具有鲜明的民族特色,浓郁的生活气息,幽默风趣,耐人寻味。因此,对汉语歇后语的正确理解和翻译,十分必要。歇后语译成英语可以有几种表达形式:第一种...歇后语是人们在生活实践中创造的一种特殊语言形式。它是人民大众喜闻乐见的一种俗语,具有鲜明的民族特色,浓郁的生活气息,幽默风趣,耐人寻味。因此,对汉语歇后语的正确理解和翻译,十分必要。歇后语译成英语可以有几种表达形式:第一种直译成英语是"rest-ending sayings",第二种是:post—pause expressions";第三种根据汉英词典译作"a two part allegoricalsaying",(of which the first part,always stated,is descriptive,while the second part,some-展开更多
During the assembly of many viruses, a powerful molecular motor packages the genome into a preassembled capsid. The Bacillus subtilis phage φ29 is an excellent model system to investigate the DNA packaging mechanism ...During the assembly of many viruses, a powerful molecular motor packages the genome into a preassembled capsid. The Bacillus subtilis phage φ29 is an excellent model system to investigate the DNA packaging mechanism because of its highly efficient in vitro DNA packaging activity and the development of a single-molecule packaging assay. Here we make use of structural and biochemical experimental data to build a physical model of DNA packaging by the φ29 DNA packaging motor. Based on the model, various dynamic behaviours such as the packaging rate, pause frequency and slip frequency under different ATP concentrations, ADP concentrations, external loads as well as capsid fillings are studied by using Monte Carlo simulation. Good agreement is obtained between the simulated and available experimental results. Moreover, we make testable predictions that should guide future experiments related to motor function.展开更多
基金the financial support from the Research Grants Council of the Hong Kong Special Administrative Region(project no.24304920).
文摘Electrochemical CO_(2) reduction reaction(CO_(2) RR)exhibits remarkable potential in producing valuable chemicals with renewable energy.Operating CO_(2) RR in acidic media is beneficial to solve the issue of low carbon utilization brought by(bi)carbonate formation at the cathode.Suppressing the competing hydrogen evolution reaction and achieving stable CO_(2) RR performance remains challenging.Herein,we constructed a 3-dimensional Cu(3D-Cu)gas diffusion electrode(GDE)to achieve efficient C_(2)H_(4) production with a partial current density(j C_(2)H_(4))of over 470 mA cm^(2) and a Faradaic efficiency(FE C_(2)H_(4)) of 40%.With pause electrolysis,the decay rate of the j C_(2)H_(4) is only half that of the traditional constant electrolysis.The GDE after constant electrolysis was found to suffer from severe salt formation,leading to the decreased activity and poor stability.
文摘In the college English classroom, pauses function to help students construct speech, promote mutual interaction and lay bare the problems to be looked into. They are critical for the Chinese students speaking English by facilitating more appropriate and complex speech in a language they are not as skilled as in their mother tongue. They are also crucial for the teachers in reflecting the cognitive activities of the students, enabling the teachers to understand and track down the speaking trouble on the spot while suggesting places for improvement in their teaching in the future.
基金supported by R&D Special Found for Public Welfare Industry (Meteorology) under Grant No. GYHY200706010
文摘Issues related to the pause of global warming in the last decade are reviewed.It is indicated that:(1) The decade of 1999-2008 is still the warmest of the last 30 years,though the global temperature increment is near zero;(2) Natural factors such as volcanism,solar radiation,ENSO,and thermohaline circulation can have impact on the inter-annual and inter-decadal variability of global mean temperatures.However,it will not mask the global warming trend for a long time;(3) Temperatures of China continue to increase in 1999-2008 with an increment of 0.4-0.5℃per 10 years.
文摘<正> Like most July days,it was hot. I stepped into a tiny ice-cream shop to cool off with a chocolate sundae. It was an old-time store, just recently restored—~* with white oak wood-work,little round tables and curlicue chairs.As I entered, 1 caught a glimpse of a very old woman bentover a table near the door.~* Her back was so badly twisted
文摘Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid Dynamics Technical Committee. Experiments were conducted in a low-speed wind tunnel at both a constant mean angle of attack and an oscillation amplitude with a reduced frequency ranging from 0.01 to 0.12. The desired stop angles of the airfoil were set to occur during the upstroke motion. The unsteady pressure distribution on the airfoil was measured for below, near, and beyond static stall conditions. Results showed that the reduced frequency and stop angle were the dominant contributors to the time lag in the flowfield. For stop angles in both belowand post-stall regions, the time for the flowfield to reach its steady state conditions, known as the time lag, decreased as the reduced frequency was increased. However, in the static-stall region and for a certain value of reduced frequency, a resonance phenomenon was observed, and a minimum time lag was achieved. The pressure distribution in this condition was shown to be highly influenced by this phenomenon.
文摘五一期间，由LAVIE HOME策划的“遇见大师．遇见艺术，遇见家”跨界合作作品展．在上海久光百货2F中庭顺利落下帷幕。展览虽然只有短短一周．但却首度将芬兰设计师器皿品牌Iittala与日本服装设计师Issey Miyake（三宅一生）历时四年共同打造的“Pause for harmony“家居系列集中展示在国人面前。跨品牌合作的”Pause for harmony”家居系列共有30件具有划时代意义的作品．
基金the National Natural Science Foundation of China(62176263,62103434,62003363)the Science Foundation for Distinguished Youth of Shaanxi Province(2021JC-35)+2 种基金the Youth Talent Promotion Program of Shaanxi Provincial Association for Science and Technology(20220123)the Natural Science Basic Research Program of Shaanxi Province(2022KJXX-99)the National Defense Basic Research Program of Technology and Industry for National Defense(JCKY2021912B001).
文摘This paper concerns minimum-energy leader-following formation design and analysis problems of distributed multiagent systems(DMASs)subjected to randomly switching topologies and aperiodic communication pauses.The critical feature of this paper is that the energy consumption during the formation control process is restricted by the minimum-energy constraint in the sense of the linear matrix inequality.Firstly,the leader-following formation control protocol is proposed based on the relative state information of neighboring agents,where the total energy consumption is considered.Then,minimum-energy leader-following formation design and analysis criteria are presented in the form of the linear matrix inequality,which can be checked by the generalized eigenvalue method.Especially,the value of the minimum-energy constraint is determined.An illustrative simulation is provided to show the effectiveness of the main results.
文摘Speaking is a productive skill and it is acknowledged to be hard for learners to master.Certain elements related to phonetics in discourse analysis,which play a significant role in EFL teaching of speaking,seem to be neglected.This paper analyses three of these elements:pause,intonation and tonic syllable,and their application in the teaching of speaking.
文摘为帮助同学们复习、掌握go on这一短语,现将其主要用法归纳如下: 一、go on作“继续”解 We’ll leave the story for the time being,and go on tomorrow。这个故事我们就讲到这里,明天再继续。① go on doing sth.意为“继续做某事”,指不停地继续做同一事情,也可指暂停后的继续。总之,go on doing sth。是继续原来的动作。
文摘歇后语是人们在生活实践中创造的一种特殊语言形式。它是人民大众喜闻乐见的一种俗语,具有鲜明的民族特色,浓郁的生活气息,幽默风趣,耐人寻味。因此,对汉语歇后语的正确理解和翻译,十分必要。歇后语译成英语可以有几种表达形式:第一种直译成英语是"rest-ending sayings",第二种是:post—pause expressions";第三种根据汉英词典译作"a two part allegoricalsaying",(of which the first part,always stated,is descriptive,while the second part,some-
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10834014 and 10674173)the National Basic Research Program of China (Grant No 2009CB930704)
文摘During the assembly of many viruses, a powerful molecular motor packages the genome into a preassembled capsid. The Bacillus subtilis phage φ29 is an excellent model system to investigate the DNA packaging mechanism because of its highly efficient in vitro DNA packaging activity and the development of a single-molecule packaging assay. Here we make use of structural and biochemical experimental data to build a physical model of DNA packaging by the φ29 DNA packaging motor. Based on the model, various dynamic behaviours such as the packaging rate, pause frequency and slip frequency under different ATP concentrations, ADP concentrations, external loads as well as capsid fillings are studied by using Monte Carlo simulation. Good agreement is obtained between the simulated and available experimental results. Moreover, we make testable predictions that should guide future experiments related to motor function.
