The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses,including electrical conductivity,mechanical properties...The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses,including electrical conductivity,mechanical properties,local corrosion properties,and slow strain rate tensile stress corrosion tests.Microstructure characterization techniques such as metallographic microscopy,scanning electron microscopy(SEM),and transmission electron microscopy(TEM)were also employed.The results indicate that the tensile strength of the alloy produced by T6I6 aging is similar to that produced by T6I4 aging,and it even exceeds 700 MPa.Furthermore,the yield strength increases by 52.7 MPa,reaching 654.8 MPa after T6I6 aging treatment.The maximum depths of intergranular corrosion(IGC)and exfoliation corrosion(EXCO)decrease from 116.3 and 468.5μm to 89.5 and 324.3μm,respectively.The stress corrosion factor also decreases from 2.1%to 1.6%.These findings suggest that the alloy treated with T6I6 aging exhibits both high strength and excellent stress corrosion cracking resistance.Similarly,when the alloy is treated with T6I4,T6I6 and T6I7 aging,the sizes of grain boundary precipitates(GBPs)are found to be 5.2,18.4,and 32.8 nm,respectively.The sizes of matrix precipitates are 4.8,5.7 and 15.7 nm,respectively.The atomic fractions of Zn in GBPs are 9.92 at.%,8.23 at.%and 6.87 at.%,respectively,while the atomic fractions of Mg are 12.66 at.%,8.43 at.%and 7.00 at.%,respectively.Additionally,the atomic fractions of Cu are 1.83 at.%,2.47 at.%and 3.41 at.%,respectively.展开更多
Novel accurate and efficient equivalent circuit trained artificial neural-network （EC-ANN） models,which inherit and improve upon EC model and EM-ANN models＇ advantages,are developed for coplanar waveguide （CPW） d...Novel accurate and efficient equivalent circuit trained artificial neural-network （EC-ANN） models,which inherit and improve upon EC model and EM-ANN models＇ advantages,are developed for coplanar waveguide （CPW） discontinuities. Modeled discontinuities include ： CPW step, interdigital capacitor, symmetric cross junction, and spiral inductor, for which validation tests are performed. These models allow for circuit design, simulation, and optimization within a CAD simulator. Design and realization of a coplanar lumped element band pass filter on GaAs using the developed CPW EC-ANN models are demonstrated.展开更多
The purpose of this paper is to examine the relationships of e-service quality dimensions with overall internet banking service quality, and its effect on customer satisfaction in the USA banking industry. The propose...The purpose of this paper is to examine the relationships of e-service quality dimensions with overall internet banking service quality, and its effect on customer satisfaction in the USA banking industry. The proposed instrument dimensions are identified based on a questionnaire survey conducted in the US. Based on an extensive review of literature, this paper proposed eight dimensions for measuring overall internet banking service quality and its subsequent effect on customer satisfaction. Also, this research uses American internet banking users as survey targets for its empirical studies. The results show significant relationships among the e-service quality dimensions （efficiency, fulfillment, system availability, privacy, assurance/trust, site aesthetics, responsiveness, and contact）, overall internet banking service quality, and customer satisfaction. Little attention has been given in the literature to understanding of the e-service quality dimensions that influence overall internet banking service quality and the specific outcome of customer satisfaction. This paper empirically examines the relationships among the eight e-service quality dimensions, overall internet banking service quality, and customer satisfaction. The findings are important to enable bank managers to have a better understanding of the key e-service quality dimensions of internet banking that affect customer satisfaction. The primary limitations of this study are the scope and size of its sample.展开更多
Effects of interrupted ageing(T6I6) and asymmetric rolling on microstructures, mechanical properties, and intergranular corrosion(IGC) behaviors of Al-Mg-Si-Zn alloy were investigated. Results showed that the T6 alloy...Effects of interrupted ageing(T6I6) and asymmetric rolling on microstructures, mechanical properties, and intergranular corrosion(IGC) behaviors of Al-Mg-Si-Zn alloy were investigated. Results showed that the T6 alloy has the lowest strength and the worst IGC resistance, while the T6I6 alloy has higher strength and better IGC resistance.What’ s more, the alloy treated by pre-rolling deformation has higher strength and better IGC resistance;and the alloy treated by the pre-asymmetry rolling achieves the highest strength, the best IGC resistance and lower elongation. The mechanical properties depend on microstructures such as the grain size, texture, dislocation density and precipitation, the grain boundary misorientation and grain boundary microstructure are responsible for the IGC resistance.展开更多
The present study employed a quantitative and network approach to detect alignment effects in second language(L2) continuation tasks designed on the xu-argument(Wang, 2016). The materials used in this study were 6 sub...The present study employed a quantitative and network approach to detect alignment effects in second language(L2) continuation tasks designed on the xu-argument(Wang, 2016). The materials used in this study were 6 sub-corpora consisting of two selected input stories and two groups of L2 written production based on two continuation tasks. During continuation, the participants were required to continue in English a story with its ending removed, with one group reading and continuing the Chinese version and the other group the English version, and then switching their roles in the two tasks. Results show that the alignment effect differs across the two versions of continuation. Specifically, compared with the Chinese-version continuation, L2 learners produced more use of unigrams and bigrams similar to the input story in terms of lexical items, frequency and ranking correlations in the English-version task;on the other hand, the English-version continuation can facilitate generating linguistic networks that are much closer to the native English networks. Moreover, this research corroborates that written production in L2 continuation tasks can be influenced by input content.展开更多
This study aims to uncover the relationship between interaction and alignment in a readingspeaking integrated continuation task, especially focusing on whether an increase in interaction intensity can lead to stronger...This study aims to uncover the relationship between interaction and alignment in a readingspeaking integrated continuation task, especially focusing on whether an increase in interaction intensity can lead to stronger alignment and further generate positive effects on L2 learning. To this end, 31 participants were asked to perform reading-speaking integrated continuation tasks under three different conditions featuring low, medium and high interaction intensity respectively. The results showed that 1) alignment existed in the reading-speaking integrated continuation task;2)increasing interaction intensity generated stronger alignment at both linguistic and situational levels;3) growing interaction intensity contributed to more coherent and accurate L2 oral production. These findings not only proved the workings of mind-body-world alignment, but also testified that increasing interaction intensity could bring about a stronger alignment effect(Wang,2010), which then contributed to better L2 oral performance. These findings confirm again the role of interaction in L2 learning and suggest that alignment could possibly be a mediating factor that links interaction and L2 development. Pedagogical implications for teaching and learning L2 speaking are discussed.展开更多
Rainwater harvesting RWH has yet to see significant uptake in UK households primarily due to a lack of innovation in residential RWH system types.This ppa er presents the results of per liminary investigations into a ...Rainwater harvesting RWH has yet to see significant uptake in UK households primarily due to a lack of innovation in residential RWH system types.This ppa er presents the results of per liminary investigations into a range of traditional and innovative residential-scale RWH systems. These systems are examined using a patent application search informal interviews with industry professionals cost-benefit analysis and a simple multi criteria analysis MCA .The latter examines the sustainability of the systems based on a priori social economic and ne vironmenat l criteria.Two of the innovative systems are subject to a more detailed analysis and benchmarked agains ta rt aditional system.Results of the MCA indicate that the innovative RWH systems achieve better sustainability scores than the traditional RWH with a lower capital cost.Further research is focused on monitoring the identified systems to generate empir cal datasets in order to undertake the WLC/LCAs and to identify challenges associated with installation.展开更多
The evolution of precipitates and mechanical properties of AZ80A magnesium alloy with aging time was studied by in situ observation with SEM,TEM and tensile testing.The results show that the continuous precipitation(C...The evolution of precipitates and mechanical properties of AZ80A magnesium alloy with aging time was studied by in situ observation with SEM,TEM and tensile testing.The results show that the continuous precipitation(CP)phases near the reaction front(RF)are replaced by the discontinuous precipitation(DP)phases at the early aging stage.In DP regions,the elliptical phases coarsen obviously with the increase of aging time,which results in a slightly slow reduction of the intracrystalline hardness of DP regions.In CP regions,some small plate phases reprecipitate simultaneously with the growth of the initial precipitates,which contributes to a slight increase in the intracrystalline hardness in CP regions at the later aging stage.The aging hardening of DP regions is faster and stronger than that of CP regions.However,the age strengthening of CP regions not only compensates for the overaging softening of DP regions but also improves the strength of the alloy.展开更多
Objective To compare the therapeutic effects and safety of monopolar and bipolar radiofrequency(RF) ablation used during cardiac surgery to treat atrial fibrillation.Methods We retrospectively studied a total of 81 pa...Objective To compare the therapeutic effects and safety of monopolar and bipolar radiofrequency(RF) ablation used during cardiac surgery to treat atrial fibrillation.Methods We retrospectively studied a total of 81 patients with chronic atrial fibrillation who underwent open cardiac surgery with concomitant RF ablation between January 2007 and March 2011.Fifty-eight patients received bipolar RF ablation and 23 received monopolar RF ablation,respectively.The sinus rhythm restoration rate,the procedural duration,the frequency of severe perioperative complications,and mortality were compared between the two groups.Results The sinus rhythm restoration rate did not differ significantly between the two groups after follow-up of 15.1 ± 12.6 months(P=0.199).The frequencies of severe perioperative complications and mortality were also similar in the two groups.The total procedural time using bipolar RF ablation was significantly shorter than that using monopolar ablation(19.7±4.6 minutes vs.28.1±8.5 minutes,P< 0.001).Conclusions Both monopolar and bipolar RF ablation are safe and effective in treating chronic atrial fibrillation patients during open cardiac surgery,but bipolar RF ablation is more convenient in practice.展开更多
基金the Tianjin Key Laboratory of Fastening and Connection Technology Enterprises 2022—2023,China(No.TKLF2022-02-C-02)the technical support from the School of Materials Science and Engineering,Central South University,China.
文摘The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses,including electrical conductivity,mechanical properties,local corrosion properties,and slow strain rate tensile stress corrosion tests.Microstructure characterization techniques such as metallographic microscopy,scanning electron microscopy(SEM),and transmission electron microscopy(TEM)were also employed.The results indicate that the tensile strength of the alloy produced by T6I6 aging is similar to that produced by T6I4 aging,and it even exceeds 700 MPa.Furthermore,the yield strength increases by 52.7 MPa,reaching 654.8 MPa after T6I6 aging treatment.The maximum depths of intergranular corrosion(IGC)and exfoliation corrosion(EXCO)decrease from 116.3 and 468.5μm to 89.5 and 324.3μm,respectively.The stress corrosion factor also decreases from 2.1%to 1.6%.These findings suggest that the alloy treated with T6I6 aging exhibits both high strength and excellent stress corrosion cracking resistance.Similarly,when the alloy is treated with T6I4,T6I6 and T6I7 aging,the sizes of grain boundary precipitates(GBPs)are found to be 5.2,18.4,and 32.8 nm,respectively.The sizes of matrix precipitates are 4.8,5.7 and 15.7 nm,respectively.The atomic fractions of Zn in GBPs are 9.92 at.%,8.23 at.%and 6.87 at.%,respectively,while the atomic fractions of Mg are 12.66 at.%,8.43 at.%and 7.00 at.%,respectively.Additionally,the atomic fractions of Cu are 1.83 at.%,2.47 at.%and 3.41 at.%,respectively.
文摘Novel accurate and efficient equivalent circuit trained artificial neural-network （EC-ANN） models,which inherit and improve upon EC model and EM-ANN models＇ advantages,are developed for coplanar waveguide （CPW） discontinuities. Modeled discontinuities include ： CPW step, interdigital capacitor, symmetric cross junction, and spiral inductor, for which validation tests are performed. These models allow for circuit design, simulation, and optimization within a CAD simulator. Design and realization of a coplanar lumped element band pass filter on GaAs using the developed CPW EC-ANN models are demonstrated.
文摘The purpose of this paper is to examine the relationships of e-service quality dimensions with overall internet banking service quality, and its effect on customer satisfaction in the USA banking industry. The proposed instrument dimensions are identified based on a questionnaire survey conducted in the US. Based on an extensive review of literature, this paper proposed eight dimensions for measuring overall internet banking service quality and its subsequent effect on customer satisfaction. Also, this research uses American internet banking users as survey targets for its empirical studies. The results show significant relationships among the e-service quality dimensions （efficiency, fulfillment, system availability, privacy, assurance/trust, site aesthetics, responsiveness, and contact）, overall internet banking service quality, and customer satisfaction. Little attention has been given in the literature to understanding of the e-service quality dimensions that influence overall internet banking service quality and the specific outcome of customer satisfaction. This paper empirically examines the relationships among the eight e-service quality dimensions, overall internet banking service quality, and customer satisfaction. The findings are important to enable bank managers to have a better understanding of the key e-service quality dimensions of internet banking that affect customer satisfaction. The primary limitations of this study are the scope and size of its sample.
基金Project(TC190H3ZV/2) supported by the National Building Project of Application Demonstration Platform on New Materials Products,China。
文摘Effects of interrupted ageing(T6I6) and asymmetric rolling on microstructures, mechanical properties, and intergranular corrosion(IGC) behaviors of Al-Mg-Si-Zn alloy were investigated. Results showed that the T6 alloy has the lowest strength and the worst IGC resistance, while the T6I6 alloy has higher strength and better IGC resistance.What’ s more, the alloy treated by pre-rolling deformation has higher strength and better IGC resistance;and the alloy treated by the pre-asymmetry rolling achieves the highest strength, the best IGC resistance and lower elongation. The mechanical properties depend on microstructures such as the grain size, texture, dislocation density and precipitation, the grain boundary misorientation and grain boundary microstructure are responsible for the IGC resistance.
文摘The present study employed a quantitative and network approach to detect alignment effects in second language(L2) continuation tasks designed on the xu-argument(Wang, 2016). The materials used in this study were 6 sub-corpora consisting of two selected input stories and two groups of L2 written production based on two continuation tasks. During continuation, the participants were required to continue in English a story with its ending removed, with one group reading and continuing the Chinese version and the other group the English version, and then switching their roles in the two tasks. Results show that the alignment effect differs across the two versions of continuation. Specifically, compared with the Chinese-version continuation, L2 learners produced more use of unigrams and bigrams similar to the input story in terms of lexical items, frequency and ranking correlations in the English-version task;on the other hand, the English-version continuation can facilitate generating linguistic networks that are much closer to the native English networks. Moreover, this research corroborates that written production in L2 continuation tasks can be influenced by input content.
基金funded by the Center for Linguistics and Applied Linguistics, Guangdong University of Foreign Studiessupported by the Graduate Program of Scientific Research and Innovation at Guangdong University of Foreign Studies (20GWCXXM-06)。
文摘This study aims to uncover the relationship between interaction and alignment in a readingspeaking integrated continuation task, especially focusing on whether an increase in interaction intensity can lead to stronger alignment and further generate positive effects on L2 learning. To this end, 31 participants were asked to perform reading-speaking integrated continuation tasks under three different conditions featuring low, medium and high interaction intensity respectively. The results showed that 1) alignment existed in the reading-speaking integrated continuation task;2)increasing interaction intensity generated stronger alignment at both linguistic and situational levels;3) growing interaction intensity contributed to more coherent and accurate L2 oral production. These findings not only proved the workings of mind-body-world alignment, but also testified that increasing interaction intensity could bring about a stronger alignment effect(Wang,2010), which then contributed to better L2 oral performance. These findings confirm again the role of interaction in L2 learning and suggest that alignment could possibly be a mediating factor that links interaction and L2 development. Pedagogical implications for teaching and learning L2 speaking are discussed.
基金Severn Trent Water and the EPSRC as part of the STREAM Engineering Doctorate Program
文摘Rainwater harvesting RWH has yet to see significant uptake in UK households primarily due to a lack of innovation in residential RWH system types.This ppa er presents the results of per liminary investigations into a range of traditional and innovative residential-scale RWH systems. These systems are examined using a patent application search informal interviews with industry professionals cost-benefit analysis and a simple multi criteria analysis MCA .The latter examines the sustainability of the systems based on a priori social economic and ne vironmenat l criteria.Two of the innovative systems are subject to a more detailed analysis and benchmarked agains ta rt aditional system.Results of the MCA indicate that the innovative RWH systems achieve better sustainability scores than the traditional RWH with a lower capital cost.Further research is focused on monitoring the identified systems to generate empir cal datasets in order to undertake the WLC/LCAs and to identify challenges associated with installation.
基金financially supported by the Natural Science Foundation of Hunan Province, China (No. 2018JJ2503)the Postgraduate Independent Exploration and Innovation Project of Central South University, China (No. 1053320171111)
文摘The evolution of precipitates and mechanical properties of AZ80A magnesium alloy with aging time was studied by in situ observation with SEM,TEM and tensile testing.The results show that the continuous precipitation(CP)phases near the reaction front(RF)are replaced by the discontinuous precipitation(DP)phases at the early aging stage.In DP regions,the elliptical phases coarsen obviously with the increase of aging time,which results in a slightly slow reduction of the intracrystalline hardness of DP regions.In CP regions,some small plate phases reprecipitate simultaneously with the growth of the initial precipitates,which contributes to a slight increase in the intracrystalline hardness in CP regions at the later aging stage.The aging hardening of DP regions is faster and stronger than that of CP regions.However,the age strengthening of CP regions not only compensates for the overaging softening of DP regions but also improves the strength of the alloy.
文摘Objective To compare the therapeutic effects and safety of monopolar and bipolar radiofrequency(RF) ablation used during cardiac surgery to treat atrial fibrillation.Methods We retrospectively studied a total of 81 patients with chronic atrial fibrillation who underwent open cardiac surgery with concomitant RF ablation between January 2007 and March 2011.Fifty-eight patients received bipolar RF ablation and 23 received monopolar RF ablation,respectively.The sinus rhythm restoration rate,the procedural duration,the frequency of severe perioperative complications,and mortality were compared between the two groups.Results The sinus rhythm restoration rate did not differ significantly between the two groups after follow-up of 15.1 ± 12.6 months(P=0.199).The frequencies of severe perioperative complications and mortality were also similar in the two groups.The total procedural time using bipolar RF ablation was significantly shorter than that using monopolar ablation(19.7±4.6 minutes vs.28.1±8.5 minutes,P< 0.001).Conclusions Both monopolar and bipolar RF ablation are safe and effective in treating chronic atrial fibrillation patients during open cardiac surgery,but bipolar RF ablation is more convenient in practice.
