Purpose:Mobile-assisted language learning(MALL)apps such as Duolingo have great potential for promoting learners'motivation to learn a second language(L2).However,little research has investigated how this motivati...Purpose:Mobile-assisted language learning(MALL)apps such as Duolingo have great potential for promoting learners'motivation to learn a second language(L2).However,little research has investigated how this motivational impact takes place.Additionally,despite the flexibility of mobile learning,most existing studies are conducted in classroom settings,with less attention paid to out-of-school technology usage.Design/Approach/Methods:To address these gaps,we present a model based on self-determination theory and propose the idea of“motivational transfer”to explain the psychological mechanism underpinning the impact of technology.To examine the model,we conducted a case study with 20 Year 8 Chinese junior school students who used Duolingo to learn English as a foreign language(EFL)after school for 6 weeks.Findings:Questionnaire and group interview data support our hypothesized mechanism:learners'activity-specific intrinsic motivation(IM)for using Duolingo and their underlying psychological need for autonomy and competence can be transferred to a more general level,thereby enhancing learners'global IMforL2.OriginalityValue:The proposed theoretical model expands our understanding of how digital technology stimulates learners'L2 motivation;it can help L2 educators design better technological affordances to promote learners'motivation both in and outside the classroom.展开更多
Large-bandwidth,high-sensitivity,and large dynamic range electric field sensors are gradually replacing their traditional counterparts.The lithium-niobate-on-insulator(LNOI)material has emerged as an ideal platform fo...Large-bandwidth,high-sensitivity,and large dynamic range electric field sensors are gradually replacing their traditional counterparts.The lithium-niobate-on-insulator(LNOI)material has emerged as an ideal platform for developing such devices,owing to its low optical loss,high electro-optical modulation efficiency,and significant bandwidth potential.In this paper,we propose and demonstrate an electric field sensor based on LNOI.The sensor consists of an asymmetric Mach–Zehnder interferometer(MZI)and a tapered dipole antenna array.The measured fiber-to-fiber loss is less than−6.7 dB,while the MZI structure exhibits an extinction ratio of greater than 20 dB.Moreover,64-QAM signals at 2 GHz were measured,showing an error vector magnitude(EVM)of less than 8%.展开更多
We propose and demonstrate an integrated microwave photonic sideband selector based on the thin-film lithium niobate(TFLN)platform by integrating an electro-optic Mach-Zehnder modulator(MZM)and a thermo-optic tunable ...We propose and demonstrate an integrated microwave photonic sideband selector based on the thin-film lithium niobate(TFLN)platform by integrating an electro-optic Mach-Zehnder modulator(MZM)and a thermo-optic tunable flat-top microring filter.The sideband selector has two functions:electro-optic modulation of wideband RF signal and sideband selection.The microwave photonic sideband selector supports processing RF signals up to 40 GHz,with undesired sidebands effectively suppressed by more than 25 d B.The demonstrated device shows great potential for TFLN integrated technology in microwave photonic applications,such as mixing and frequency measurement.展开更多
研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的预测模型预测日粮瘤胃pH值与微生物蛋白质(MCP)合成量,并通过实测验证模型预测值的准确性。选取3只安装瘤胃和十二指肠...研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的预测模型预测日粮瘤胃pH值与微生物蛋白质(MCP)合成量,并通过实测验证模型预测值的准确性。选取3只安装瘤胃和十二指肠瘘管的哈萨克公羊为试验动物,配制3种精粗比为30:70、35:65、40:60的全混合日粮(TMR)。采用3×3拉丁方设计,共3期试验,每期18 d,其中10 d为预试期,8 d为样品采集,测定瘤胃液pH和MCP合成量。同时利用CNCPS-S模型预测3种日粮的MCP合成量,评价模型预测的准确性。结果表明:①3种TMR的瘤胃液pH的实测值分别在6.38~6.71、6.01~6.59、5.81~6.41之间,模型预测pH为固定值6.46;②随着精料水平增加,3种TMR均为瘤胃能氮负平衡型,瘤胃能氮平衡(RENB)值均呈下降趋势(P<0.05),3种TMR的MCP的模型预测值依次升高,分别为210.29、215.31、246.94 g/d(P>0.05),实测值也依次升高,分别为93.83、97.33、100.27 g/d(P<0.05);③经线性回归分析,3种日粮MCP的预测值与十二指肠MCP实测值之间的平均偏差比较大(平均偏差≥116 g/d),相关性低(R^2≤0.75),误差均方根(RMSE)都较高。以上结果说明,CNCPS-S对我国绵羊瘤胃pH值具有较好的预测能力,但对MCP合成量具有较低的预测能力。展开更多
本研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的瘤胃降解预测模型预测日粮碳水化合物(CHO)瘤胃有效降解率,并实测验证CNCPS-S模型预测值的准确性。选取3只安装瘤胃...本研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的瘤胃降解预测模型预测日粮碳水化合物(CHO)瘤胃有效降解率,并实测验证CNCPS-S模型预测值的准确性。选取3只安装瘤胃瘘管、体重分别为(38.03±1.56)kg的哈萨克公羊作为试验动物,配制3种精粗比分别为30∶70、35∶65、40∶60的全混合日粮(TMR),利用瘤胃灌注试验和尼龙袋试验实测3种日粮CHO的瘤胃外流速度(Kp)和降解率,同时利用CNCPS-S模型预测3种日粮CHO的Kp与降解率,对CHO的降解率预测值和实测值进行线性回归分析,评价模型预测的准确性。结果表明:3种TMR的瘤胃食糜Kp随精料比例增加而依次升高(P<0.01),分别为3.58%/h、3.83%/h、4.05%/h,据此计算而得的CHO的降解率分别为42.7%、43.1%、42.3%(P>0.05);随精料比例的增加,3种TMR的瘤胃食糜Kp的模型预测值依次升高(P>0.05),分别为1.62%/h、1.63%/h、1.64%/h,CHO瘤胃降解率的预测值分别为39.5%、39.1%、39.6%(P>0.05);3种日粮CHO瘤胃降解率的预测值与实测值之间的平均偏差比较小(≤4 g/100 g CHO),相关性较高(R2≥0.86),均方根误差也较低(RMSE≤1.93 g/100 g CHO)。以上结果说明,CNCPS-S瘤胃降解预测模型对日粮CHO的降解率具有较好的预测能力。展开更多
硫化物Li_(3)PS_(4)是重要的含硫快离子导体,锂离子电导率高,机械性能优异,化学兼容性好,属于全固态电池中一类重要的固态电解质.Li_(3)PS_(4)具有多种晶体结构(玻璃态、α相、β相、γ相),而晶体结构对于材料离子电导率有决定性的影响...硫化物Li_(3)PS_(4)是重要的含硫快离子导体,锂离子电导率高,机械性能优异,化学兼容性好,属于全固态电池中一类重要的固态电解质.Li_(3)PS_(4)具有多种晶体结构(玻璃态、α相、β相、γ相),而晶体结构对于材料离子电导率有决定性的影响,因此探究不同Li_(3)PS_(4)晶体结构的合成条件及其转变过程对固态电解质的应用有重要意义.本文通过原位变温Raman和室温X射线衍射(XRD)分析发现,通过球磨法所得glass-Li_(3)PS_(4)在首次升温过程中(240℃)优先转变为亚稳态的β-Li_(3)PS_(4),此时冷却到室温能保持β相结构,并具有较高的离子电导率(0.65 mS cm^(-1)).当烧结温度继续升高(>480℃),β相会转变为离子电导率更高但热力学不稳定的α-Li_(3)PS_(4),在后续的降温过程中,α相会直接转变为热力学更稳定但离子电导率差的γ-Li_(3)PS_(4).此外,γ-Li_(3)PS_(4)和β-Li_(3)PS_(4)具有一定的结构记忆效应,即使经历二次低温烧结后(240℃)也能维持其固有的结构.以上结果表明,首次烧结温度对于Li_(3)PS_(4)材料的结构和离子电导率具有重要的影响,合理控制烧结温度能够成功制备出具有更高离子电导率的β-Li_(3)PS_(4)固态电解质.此外,所制备的β-Li_(3)PS_(4)固态电解质对锂表现出相对优异的界面性能.展开更多
基金the China Scholarship Council(Grant No.202006380078)。
文摘Purpose:Mobile-assisted language learning(MALL)apps such as Duolingo have great potential for promoting learners'motivation to learn a second language(L2).However,little research has investigated how this motivational impact takes place.Additionally,despite the flexibility of mobile learning,most existing studies are conducted in classroom settings,with less attention paid to out-of-school technology usage.Design/Approach/Methods:To address these gaps,we present a model based on self-determination theory and propose the idea of“motivational transfer”to explain the psychological mechanism underpinning the impact of technology.To examine the model,we conducted a case study with 20 Year 8 Chinese junior school students who used Duolingo to learn English as a foreign language(EFL)after school for 6 weeks.Findings:Questionnaire and group interview data support our hypothesized mechanism:learners'activity-specific intrinsic motivation(IM)for using Duolingo and their underlying psychological need for autonomy and competence can be transferred to a more general level,thereby enhancing learners'global IMforL2.OriginalityValue:The proposed theoretical model expands our understanding of how digital technology stimulates learners'L2 motivation;it can help L2 educators design better technological affordances to promote learners'motivation both in and outside the classroom.
基金supported by the National Natural Science Foundation of China (52072138 and 51772115)the National Key Research and Development Program of China (2018YFE0206900)Australian Research Council (ARC) through the Discovery Project (DP180102297)。
基金supported by the National Key Research and Development Program of China(No.2021YFB2800104)the National Natural Science Foundation of China(Nos.62175079 and 62205119).
文摘Large-bandwidth,high-sensitivity,and large dynamic range electric field sensors are gradually replacing their traditional counterparts.The lithium-niobate-on-insulator(LNOI)material has emerged as an ideal platform for developing such devices,owing to its low optical loss,high electro-optical modulation efficiency,and significant bandwidth potential.In this paper,we propose and demonstrate an electric field sensor based on LNOI.The sensor consists of an asymmetric Mach–Zehnder interferometer(MZI)and a tapered dipole antenna array.The measured fiber-to-fiber loss is less than−6.7 dB,while the MZI structure exhibits an extinction ratio of greater than 20 dB.Moreover,64-QAM signals at 2 GHz were measured,showing an error vector magnitude(EVM)of less than 8%.
基金supported by the National Key Research and Development Program of China(No.2021YFB2800104)the National Natural Science Foundation of China(Nos.62175079 and 62205119)。
文摘We propose and demonstrate an integrated microwave photonic sideband selector based on the thin-film lithium niobate(TFLN)platform by integrating an electro-optic Mach-Zehnder modulator(MZM)and a thermo-optic tunable flat-top microring filter.The sideband selector has two functions:electro-optic modulation of wideband RF signal and sideband selection.The microwave photonic sideband selector supports processing RF signals up to 40 GHz,with undesired sidebands effectively suppressed by more than 25 d B.The demonstrated device shows great potential for TFLN integrated technology in microwave photonic applications,such as mixing and frequency measurement.
文摘研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的预测模型预测日粮瘤胃pH值与微生物蛋白质(MCP)合成量,并通过实测验证模型预测值的准确性。选取3只安装瘤胃和十二指肠瘘管的哈萨克公羊为试验动物,配制3种精粗比为30:70、35:65、40:60的全混合日粮(TMR)。采用3×3拉丁方设计,共3期试验,每期18 d,其中10 d为预试期,8 d为样品采集,测定瘤胃液pH和MCP合成量。同时利用CNCPS-S模型预测3种日粮的MCP合成量,评价模型预测的准确性。结果表明:①3种TMR的瘤胃液pH的实测值分别在6.38~6.71、6.01~6.59、5.81~6.41之间,模型预测pH为固定值6.46;②随着精料水平增加,3种TMR均为瘤胃能氮负平衡型,瘤胃能氮平衡(RENB)值均呈下降趋势(P<0.05),3种TMR的MCP的模型预测值依次升高,分别为210.29、215.31、246.94 g/d(P>0.05),实测值也依次升高,分别为93.83、97.33、100.27 g/d(P<0.05);③经线性回归分析,3种日粮MCP的预测值与十二指肠MCP实测值之间的平均偏差比较大(平均偏差≥116 g/d),相关性低(R^2≤0.75),误差均方根(RMSE)都较高。以上结果说明,CNCPS-S对我国绵羊瘤胃pH值具有较好的预测能力,但对MCP合成量具有较低的预测能力。
文摘本研究旨在应用康奈尔绵羊净碳水化合物和蛋白质体系(Cornell sheep net carbohydrate and protein system,CNCPS-S)的瘤胃降解预测模型预测日粮碳水化合物(CHO)瘤胃有效降解率,并实测验证CNCPS-S模型预测值的准确性。选取3只安装瘤胃瘘管、体重分别为(38.03±1.56)kg的哈萨克公羊作为试验动物,配制3种精粗比分别为30∶70、35∶65、40∶60的全混合日粮(TMR),利用瘤胃灌注试验和尼龙袋试验实测3种日粮CHO的瘤胃外流速度(Kp)和降解率,同时利用CNCPS-S模型预测3种日粮CHO的Kp与降解率,对CHO的降解率预测值和实测值进行线性回归分析,评价模型预测的准确性。结果表明:3种TMR的瘤胃食糜Kp随精料比例增加而依次升高(P<0.01),分别为3.58%/h、3.83%/h、4.05%/h,据此计算而得的CHO的降解率分别为42.7%、43.1%、42.3%(P>0.05);随精料比例的增加,3种TMR的瘤胃食糜Kp的模型预测值依次升高(P>0.05),分别为1.62%/h、1.63%/h、1.64%/h,CHO瘤胃降解率的预测值分别为39.5%、39.1%、39.6%(P>0.05);3种日粮CHO瘤胃降解率的预测值与实测值之间的平均偏差比较小(≤4 g/100 g CHO),相关性较高(R2≥0.86),均方根误差也较低(RMSE≤1.93 g/100 g CHO)。以上结果说明,CNCPS-S瘤胃降解预测模型对日粮CHO的降解率具有较好的预测能力。
文摘硫化物Li_(3)PS_(4)是重要的含硫快离子导体,锂离子电导率高,机械性能优异,化学兼容性好,属于全固态电池中一类重要的固态电解质.Li_(3)PS_(4)具有多种晶体结构(玻璃态、α相、β相、γ相),而晶体结构对于材料离子电导率有决定性的影响,因此探究不同Li_(3)PS_(4)晶体结构的合成条件及其转变过程对固态电解质的应用有重要意义.本文通过原位变温Raman和室温X射线衍射(XRD)分析发现,通过球磨法所得glass-Li_(3)PS_(4)在首次升温过程中(240℃)优先转变为亚稳态的β-Li_(3)PS_(4),此时冷却到室温能保持β相结构,并具有较高的离子电导率(0.65 mS cm^(-1)).当烧结温度继续升高(>480℃),β相会转变为离子电导率更高但热力学不稳定的α-Li_(3)PS_(4),在后续的降温过程中,α相会直接转变为热力学更稳定但离子电导率差的γ-Li_(3)PS_(4).此外,γ-Li_(3)PS_(4)和β-Li_(3)PS_(4)具有一定的结构记忆效应,即使经历二次低温烧结后(240℃)也能维持其固有的结构.以上结果表明,首次烧结温度对于Li_(3)PS_(4)材料的结构和离子电导率具有重要的影响,合理控制烧结温度能够成功制备出具有更高离子电导率的β-Li_(3)PS_(4)固态电解质.此外,所制备的β-Li_(3)PS_(4)固态电解质对锂表现出相对优异的界面性能.
