The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor ...The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.展开更多
[Objectives]To compare content of proanthocyanidins and polysaccharides in wild Lycium ruthenicum.[Methods]The wild L.ruthenicum collected from different regions such as Qinghai,Inner Mongolia,Ningxia and Gansu Provin...[Objectives]To compare content of proanthocyanidins and polysaccharides in wild Lycium ruthenicum.[Methods]The wild L.ruthenicum collected from different regions such as Qinghai,Inner Mongolia,Ningxia and Gansu Province were taken as the research objects.The conventional indicators such as proanthocyanidins and polysaccharides of the experimental materials were determined,and the proanthocyanidins and polysaccharides of the experimental materials in different regions were compared and analyzed.The difference in content and correlation,and the cluster analysis method were used to divide clusters of the experimental materials.[Results]The absorbance of proanthocyanidins in the fruit of wild L.ruthenicum was No.4>No.1>No.5>No.6>No.3>No.2,among which the absorbance of anthocyanin(2.43)of wild L.ruthenicum variety No.4 was significantly higher than other experimental materials(P<0.05),and proanthocyanidin of No.2 had the lowest absorbance value of 1.35.There was no significant difference between No.3 and No.6(P>0.05),and there were significant differences among other experimental materials(P<0.05).The content of polysaccharides was:No.3>No.7>No.2>No.4>No.5>No.6>No.1;there was no significant difference between No.3 and No.7(P>0.05),but significantly higher than other materials(P<0.05).Besides,proanthocyanidins and polysaccharides showed significant variability,but there was no consistency in the correlation between them.[Conclusions]In terms of the absorbance of proanthocyanidins,the experimental materials No.1 and No.4 can be classified into a cluster;experimental materials No.2,No.3,No.5 and No.6 can be classified into another cluster.This can provide a theoretical basis for the introduction and breeding of fine varieties.展开更多
为了提高高速车辆-道岔复杂动力学响应的仿真计算效率和计算精度,构建了基于长短时记忆(Long Short Term Memory,LSTM)网络的动力学响应预测模型。首先,利用刚柔耦合动力学模型,生成不同水平不平顺状态下的轮轨垂向力样本。然后,将水平...为了提高高速车辆-道岔复杂动力学响应的仿真计算效率和计算精度,构建了基于长短时记忆(Long Short Term Memory,LSTM)网络的动力学响应预测模型。首先,利用刚柔耦合动力学模型,生成不同水平不平顺状态下的轮轨垂向力样本。然后,将水平不平顺幅值作为模型输入,轮轨垂向力作为输出,引入dropout参数,训练LSTM网络并采用均方误差和决定系数来评价模型性能。最后,基于计算结果分析轮重减载率和统计超限概率。结果表明:本文搭建的LSTM网络在训练轮次达到5000次后,均方误差基本稳定在0.00267,测试集的决定系数为0.903,模型具有较高的可靠性,可用于预测不平顺状态下的车辆-道岔动力学响应;与传统动力学模型计算相比,LSTM模型计算效率提高了约26倍,大幅提高了计算效率且计算精度达到要求;水平不平顺幅值达到6 mm时,超限概率达到了9.08%,超过了容许阈值。展开更多
文摘The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.
基金Supported by Science and Technology Program of Inner Mongolia(201602083)Special Fund for Scientific Research of Inner Mongolia Agricultural University"Special Program for Breeding(Selection)of Animal and Plant Varieties"(YZGC2017023)
文摘[Objectives]To compare content of proanthocyanidins and polysaccharides in wild Lycium ruthenicum.[Methods]The wild L.ruthenicum collected from different regions such as Qinghai,Inner Mongolia,Ningxia and Gansu Province were taken as the research objects.The conventional indicators such as proanthocyanidins and polysaccharides of the experimental materials were determined,and the proanthocyanidins and polysaccharides of the experimental materials in different regions were compared and analyzed.The difference in content and correlation,and the cluster analysis method were used to divide clusters of the experimental materials.[Results]The absorbance of proanthocyanidins in the fruit of wild L.ruthenicum was No.4>No.1>No.5>No.6>No.3>No.2,among which the absorbance of anthocyanin(2.43)of wild L.ruthenicum variety No.4 was significantly higher than other experimental materials(P<0.05),and proanthocyanidin of No.2 had the lowest absorbance value of 1.35.There was no significant difference between No.3 and No.6(P>0.05),and there were significant differences among other experimental materials(P<0.05).The content of polysaccharides was:No.3>No.7>No.2>No.4>No.5>No.6>No.1;there was no significant difference between No.3 and No.7(P>0.05),but significantly higher than other materials(P<0.05).Besides,proanthocyanidins and polysaccharides showed significant variability,but there was no consistency in the correlation between them.[Conclusions]In terms of the absorbance of proanthocyanidins,the experimental materials No.1 and No.4 can be classified into a cluster;experimental materials No.2,No.3,No.5 and No.6 can be classified into another cluster.This can provide a theoretical basis for the introduction and breeding of fine varieties.
文摘为了提高高速车辆-道岔复杂动力学响应的仿真计算效率和计算精度,构建了基于长短时记忆(Long Short Term Memory,LSTM)网络的动力学响应预测模型。首先,利用刚柔耦合动力学模型,生成不同水平不平顺状态下的轮轨垂向力样本。然后,将水平不平顺幅值作为模型输入,轮轨垂向力作为输出,引入dropout参数,训练LSTM网络并采用均方误差和决定系数来评价模型性能。最后,基于计算结果分析轮重减载率和统计超限概率。结果表明:本文搭建的LSTM网络在训练轮次达到5000次后,均方误差基本稳定在0.00267,测试集的决定系数为0.903,模型具有较高的可靠性,可用于预测不平顺状态下的车辆-道岔动力学响应;与传统动力学模型计算相比,LSTM模型计算效率提高了约26倍,大幅提高了计算效率且计算精度达到要求;水平不平顺幅值达到6 mm时,超限概率达到了9.08%,超过了容许阈值。
