High resolution angle-resolved photoemission spectroscopy(ARPES)measurements are carried out on CaKFe_4 As_4,KCa_2 Fe_4 As_4 F_2 and(Ba_(0.6)K_(0.4))Fe_2 As_2 superconductors.Clear evidence of band folding between the...High resolution angle-resolved photoemission spectroscopy(ARPES)measurements are carried out on CaKFe_4 As_4,KCa_2 Fe_4 As_4 F_2 and(Ba_(0.6)K_(0.4))Fe_2 As_2 superconductors.Clear evidence of band folding between the Brillouin zone center and corners with a(π,π)wave vector has been found from the measured Fermi surface and band structures in all the three kinds of superconductors.A dominant √2×√2 surface reconstruction is observed on the cleaved surface of CaKFe_4As_4 by scanning tunneling microscopy(STM)measurements.We propose that the commonly observed √2×√2 reconstruction in the FeAs-based superconductors provides a general scenario to understand the origin of the(π,π)band folding.Our observations provide new insights in understanding the electronic structure and superconductivity mechanism in iron-based superconductors.展开更多
The outside serrated integral-fin tubes fabricated by rolling-plowing-extrusion processing were surface-treated through different processes of annealing in hydrogen atmosphere,electrochemical corrosion or sandblasting...The outside serrated integral-fin tubes fabricated by rolling-plowing-extrusion processing were surface-treated through different processes of annealing in hydrogen atmosphere,electrochemical corrosion or sandblasting.The purpose was to eliminate residual stress,clear secondary micro-fins and enhance heat transfer performance.By comparing the surface characteristics,it is found that the finned tubes treated by electrochemical corrosion have the most glabrous surfaces where the fins are almost perfectly reserved.Clear layer cracks can be observed on the top of the fins.These structures are effective in enhancing heat transfer performance when being applied to flow heat exchange.Therefore,the finned tubes treated by electrochemical corrosion are proper for the tubular exchanger with water coolant.The finned tubes treated by sandblasting have rougher surfaces with layer cracks and micro gaps removed.As these structures are useful to clearing adhesive feculence,the tubes are more suitable for the tubular heat exchanger with oil coolant.展开更多
The thin-walled tube flexure（TWTF） hinges have important potential application value in the deployment mechanisms of satellite and solar array, but the optimal design of the TWTF hinges haven＇t been completely solv...The thin-walled tube flexure（TWTF） hinges have important potential application value in the deployment mechanisms of satellite and solar array, but the optimal design of the TWTF hinges haven＇t been completely solved, which restricts their applications. An optimal design method for the qusai-static folding and deploying of TWTF hinges with double slots is presented based on the response surface theory. Firstly, the full factorial method is employed to design of the experiments. Then, the finite element models of the TWTF hinges with double slots are constructed to simulate the qusai-static folding and deploying non-linear analysis. What＇s more, the mathematical model of the TWTF flexure hinge quasi-static folding and deploying properties are derived by the response surface method. Considering of small mass and high stability, the peak moment of quasi-static folding and deploying as well as the lightless are set as the objectives to get the optimal performances. The relative errors of the objectives between the optimal design results and the FE analysis results are less than 7%, which demonstrates the precision of the surrogate models. Lastly, the parameter study shows that both the slots length and the slots width both have significant effects to the peak moment of quasi-static folding and deploying of TWTF hinges with double slots. However, the maximum Mises stress of quasi-static folding is more sensitive to the slots length than the slots width. The proposed research can be applied to optimize other thin-walled flexure hinges under quasi-static folding and deploying, which is of great importance to design of flexure hinges with high stability and low stress.展开更多
Metal batteries that directly use active metals as anodes are considered as one of the most promising solutions to achieve the energy upgrade of battery technologies,while their practical application still suffers fro...Metal batteries that directly use active metals as anodes are considered as one of the most promising solutions to achieve the energy upgrade of battery technologies,while their practical application still suffers from dendrite problems.Functional carbon materials(FCMs)have demonstrated their great potential in suppressing metal dendrites benefitting from the multiple merits such as chemical tunability and capability of multi-dimensional structure assembly.Here,we initiate a review to present the recent progress in employing FCMs to deal with dendrite problems.It focuses on the surface chemistry and multi-dimensional carbon material engineering,which systematically overcomes the problems through diverse methods,such as reinforcing desolvation,improving interface compatibility,homogenizing electric field,buffering volume expansion and lattice mismatch.In addition,we also refine the long-standing debate about whether surface defects in FCMs are beneficial to suppress the metal dendrites or not,especially in the non-aqueous electrolyte regime.Finally,the remaining challenges for utilizing FCMs to suppress metal dendrites and the possible solutions are proposed to guide the future development.展开更多
The change of vocal flinction after vocal fold dehydration due to dryness was discussed along with the treatment eHect of different atomizing agents.Forty-eight staffs from The Central Hospital of Wuhan were recniited...The change of vocal flinction after vocal fold dehydration due to dryness was discussed along with the treatment eHect of different atomizing agents.Forty-eight staffs from The Central Hospital of Wuhan were recniited.All volunteers breathed dry air for vocal fold dehydration.After dry air inhalation,the subjects were randomly divided into four groups,with 12 cases each.Three groups were treatment groups,receiving 0.9%nonnal saline(IS),5%hypertonic saline(HS)and double-distilled water(SW)atomizing inhalation therapy,respectively,and the last group was the control group without treatment.Voice data were collected for all subjects before and immediately after dry air inhalation using the Multi-Dimensional Voice Program(MDVP)system.Atomizing inhalation therapy was given 10 min after dry air inhalation,and voice data were collected using MDVP system at the following time points after atomizing inhalation treatment:5 min,20 min,35 min,50 min,65 min,80 min,95 min,110 min.In the control group,voice data were collected at the same time points and compared with those of treatment groups.The vocal function parameters collected before and after dry air inhalation as well as after treatment were subjected to test using SPSS 16.0 software.In the four groups,jitter(fundamental frequency perturbation),shimmer(amplitude perturbation),and amplitude perturbation quotient(APQ)were significantly increased after dry air inhalation(P<0.05).In IS,HS and SW groups,after atomizing inhalation treatment,there was an obvious reduction in jitter,shimmer and APQ,showing significant differences as compared with those after dry air inhalation(P<0.05).Moreover,these parameters were significantly lower than those in the control group(P<0.05).The jitter,shimmer and APQ in the IS group were significantly lower than those in the HS and SW groups(P<0.05).We are led to a con elusion:Vocal fold dehydration induced by dryness can reduce the stability of voice;such decreased voice stability can be improved by atomizing inhalation therapy;without proper treatment,voice stability caused by vocal fold dehydration cannot heal spontaneously;of three atomizing agents namely,IS,HS and SW,IS had the best treatment effect for decreased voice stability caused by vocal fold dehydration.展开更多
The northern Sichuan Basin,spreading in the northern section of the Longmenshan Fault Fold Belt,is characterized by dramatic fluctuations in the surface landforms,development of abdominal faults,and low-quality seismi...The northern Sichuan Basin,spreading in the northern section of the Longmenshan Fault Fold Belt,is characterized by dramatic fluctuations in the surface landforms,development of abdominal faults,and low-quality seismic data,resulting in difficulties in clarifying relevant structures.The key target formation,the Mid-Permian Qixia Fm,is deeply buried with thin reservoirs and high heterogeneity,which brings great challenges to seismic prediction.Under such circumstances,researches have been conducted jointly in terms of seismic data acquisition,processing and interpretation,and finally some relevant seismic survey technologies were developed suitable for surface/underground complex structures.Through surface structural surveys,dynamic deep-well lithologic identification,single-point detector deployment and process optimization,acquisition parameters can be excited.In addition,by using an observation systemwith high-coverage,wide-azimuth and huge-displacement,quality of acquired seismic data can be enhanced dramatically.Seismic imaging technologies for complex structures have been developed to enhance the quality of images for deep formations.These technologies are dominated by microscopic logging-constrained tomography static correction,high-resolution processing with fidelity and amplitude preservation and all-around PSDM in an angular domain.By using high-resolution gravity,magnetic and electric data,details related to geological structures and faults can be identified.In combination with fine seismic data interpretation,structural details and fault features can be verified effectively.Based on forwardmodeling and fine seismic calibration of reservoirs in individualwells,suitable attributes can be identified for predictions related to the distribution of reservoirs.By using all these auxiliary technologies,a large-scale structuralelithologic composite trap with a total area of 1223 km^(2) has been discovered in the NW Sichuan Basin.The Shuangyushi-Jiangyou area as a whole distributes on structural highs.In the areas to the south of Shuangyushi,the Qixia Fm dolomite reservoirs of platform margins are continuously developed.In conclusion,these auxiliary technologies can effectively allow trap identification and thin reservoir prediction in complex structures in the study area.In addition to clarifying the exploration orientation and providing a necessarily technical supports forwell development,these technologies help to accelerate the construction of demonstration projects for the exploration and development of deep marine carbonate formations.展开更多
基金Supported by the National Key Research and Development Program of China (Grant Nos.2016YFA0300300,2017YFA0302900,2018YFA0704200 and 2019YFA0308000)the National Natural Science Foundation of China (Grant Nos.11888101,11922414 and11874405)+2 种基金the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No.XDB25000000)the Youth Innovation Promotion Association of CAS (Grant No.2017013)the Research Program of Beijing Academy of Quantum Information Sciences (Grant No.Y18G06)。
文摘High resolution angle-resolved photoemission spectroscopy(ARPES)measurements are carried out on CaKFe_4 As_4,KCa_2 Fe_4 As_4 F_2 and(Ba_(0.6)K_(0.4))Fe_2 As_2 superconductors.Clear evidence of band folding between the Brillouin zone center and corners with a(π,π)wave vector has been found from the measured Fermi surface and band structures in all the three kinds of superconductors.A dominant √2×√2 surface reconstruction is observed on the cleaved surface of CaKFe_4As_4 by scanning tunneling microscopy(STM)measurements.We propose that the commonly observed √2×√2 reconstruction in the FeAs-based superconductors provides a general scenario to understand the origin of the(π,π)band folding.Our observations provide new insights in understanding the electronic structure and superconductivity mechanism in iron-based superconductors.
基金Projects(50675070,50930005) supported by the National Natural Science Foundation of ChinaProject(U0834002) supported by the Natural Science Foundation of Guangdong Province,China
文摘The outside serrated integral-fin tubes fabricated by rolling-plowing-extrusion processing were surface-treated through different processes of annealing in hydrogen atmosphere,electrochemical corrosion or sandblasting.The purpose was to eliminate residual stress,clear secondary micro-fins and enhance heat transfer performance.By comparing the surface characteristics,it is found that the finned tubes treated by electrochemical corrosion have the most glabrous surfaces where the fins are almost perfectly reserved.Clear layer cracks can be observed on the top of the fins.These structures are effective in enhancing heat transfer performance when being applied to flow heat exchange.Therefore,the finned tubes treated by electrochemical corrosion are proper for the tubular exchanger with water coolant.The finned tubes treated by sandblasting have rougher surfaces with layer cracks and micro gaps removed.As these structures are useful to clearing adhesive feculence,the tubes are more suitable for the tubular heat exchanger with oil coolant.
基金supported by National Natural Science Foundation ofChina(Grant No.50935002)
文摘The thin-walled tube flexure（TWTF） hinges have important potential application value in the deployment mechanisms of satellite and solar array, but the optimal design of the TWTF hinges haven＇t been completely solved, which restricts their applications. An optimal design method for the qusai-static folding and deploying of TWTF hinges with double slots is presented based on the response surface theory. Firstly, the full factorial method is employed to design of the experiments. Then, the finite element models of the TWTF hinges with double slots are constructed to simulate the qusai-static folding and deploying non-linear analysis. What＇s more, the mathematical model of the TWTF flexure hinge quasi-static folding and deploying properties are derived by the response surface method. Considering of small mass and high stability, the peak moment of quasi-static folding and deploying as well as the lightless are set as the objectives to get the optimal performances. The relative errors of the objectives between the optimal design results and the FE analysis results are less than 7%, which demonstrates the precision of the surrogate models. Lastly, the parameter study shows that both the slots length and the slots width both have significant effects to the peak moment of quasi-static folding and deploying of TWTF hinges with double slots. However, the maximum Mises stress of quasi-static folding is more sensitive to the slots length than the slots width. The proposed research can be applied to optimize other thin-walled flexure hinges under quasi-static folding and deploying, which is of great importance to design of flexure hinges with high stability and low stress.
基金supported by the Fundamental Research Funds for the Central Universities,China(buctrc202029,buctrc202129)the Beijing Nova Program(Z211100002121093)。
文摘Metal batteries that directly use active metals as anodes are considered as one of the most promising solutions to achieve the energy upgrade of battery technologies,while their practical application still suffers from dendrite problems.Functional carbon materials(FCMs)have demonstrated their great potential in suppressing metal dendrites benefitting from the multiple merits such as chemical tunability and capability of multi-dimensional structure assembly.Here,we initiate a review to present the recent progress in employing FCMs to deal with dendrite problems.It focuses on the surface chemistry and multi-dimensional carbon material engineering,which systematically overcomes the problems through diverse methods,such as reinforcing desolvation,improving interface compatibility,homogenizing electric field,buffering volume expansion and lattice mismatch.In addition,we also refine the long-standing debate about whether surface defects in FCMs are beneficial to suppress the metal dendrites or not,especially in the non-aqueous electrolyte regime.Finally,the remaining challenges for utilizing FCMs to suppress metal dendrites and the possible solutions are proposed to guide the future development.
文摘The change of vocal flinction after vocal fold dehydration due to dryness was discussed along with the treatment eHect of different atomizing agents.Forty-eight staffs from The Central Hospital of Wuhan were recniited.All volunteers breathed dry air for vocal fold dehydration.After dry air inhalation,the subjects were randomly divided into four groups,with 12 cases each.Three groups were treatment groups,receiving 0.9%nonnal saline(IS),5%hypertonic saline(HS)and double-distilled water(SW)atomizing inhalation therapy,respectively,and the last group was the control group without treatment.Voice data were collected for all subjects before and immediately after dry air inhalation using the Multi-Dimensional Voice Program(MDVP)system.Atomizing inhalation therapy was given 10 min after dry air inhalation,and voice data were collected using MDVP system at the following time points after atomizing inhalation treatment:5 min,20 min,35 min,50 min,65 min,80 min,95 min,110 min.In the control group,voice data were collected at the same time points and compared with those of treatment groups.The vocal function parameters collected before and after dry air inhalation as well as after treatment were subjected to test using SPSS 16.0 software.In the four groups,jitter(fundamental frequency perturbation),shimmer(amplitude perturbation),and amplitude perturbation quotient(APQ)were significantly increased after dry air inhalation(P<0.05).In IS,HS and SW groups,after atomizing inhalation treatment,there was an obvious reduction in jitter,shimmer and APQ,showing significant differences as compared with those after dry air inhalation(P<0.05).Moreover,these parameters were significantly lower than those in the control group(P<0.05).The jitter,shimmer and APQ in the IS group were significantly lower than those in the HS and SW groups(P<0.05).We are led to a con elusion:Vocal fold dehydration induced by dryness can reduce the stability of voice;such decreased voice stability can be improved by atomizing inhalation therapy;without proper treatment,voice stability caused by vocal fold dehydration cannot heal spontaneously;of three atomizing agents namely,IS,HS and SW,IS had the best treatment effect for decreased voice stability caused by vocal fold dehydration.
基金Project supported by the National Major Science and Technology Project“Development of Large Oil/Gas Fields and Coalbed Methane”(No.2016ZX05004-005&2016ZX05007-004)the CNPC Major Science and Technology Project“Research and application of key technologies for maintaining gas productivity of 30 billion cubic meters in Southwest Oil and Gas Fields”(No.2016E-06,2016E-0602,2016E-0603&2016E-0604).
文摘The northern Sichuan Basin,spreading in the northern section of the Longmenshan Fault Fold Belt,is characterized by dramatic fluctuations in the surface landforms,development of abdominal faults,and low-quality seismic data,resulting in difficulties in clarifying relevant structures.The key target formation,the Mid-Permian Qixia Fm,is deeply buried with thin reservoirs and high heterogeneity,which brings great challenges to seismic prediction.Under such circumstances,researches have been conducted jointly in terms of seismic data acquisition,processing and interpretation,and finally some relevant seismic survey technologies were developed suitable for surface/underground complex structures.Through surface structural surveys,dynamic deep-well lithologic identification,single-point detector deployment and process optimization,acquisition parameters can be excited.In addition,by using an observation systemwith high-coverage,wide-azimuth and huge-displacement,quality of acquired seismic data can be enhanced dramatically.Seismic imaging technologies for complex structures have been developed to enhance the quality of images for deep formations.These technologies are dominated by microscopic logging-constrained tomography static correction,high-resolution processing with fidelity and amplitude preservation and all-around PSDM in an angular domain.By using high-resolution gravity,magnetic and electric data,details related to geological structures and faults can be identified.In combination with fine seismic data interpretation,structural details and fault features can be verified effectively.Based on forwardmodeling and fine seismic calibration of reservoirs in individualwells,suitable attributes can be identified for predictions related to the distribution of reservoirs.By using all these auxiliary technologies,a large-scale structuralelithologic composite trap with a total area of 1223 km^(2) has been discovered in the NW Sichuan Basin.The Shuangyushi-Jiangyou area as a whole distributes on structural highs.In the areas to the south of Shuangyushi,the Qixia Fm dolomite reservoirs of platform margins are continuously developed.In conclusion,these auxiliary technologies can effectively allow trap identification and thin reservoir prediction in complex structures in the study area.In addition to clarifying the exploration orientation and providing a necessarily technical supports forwell development,these technologies help to accelerate the construction of demonstration projects for the exploration and development of deep marine carbonate formations.
