Broadening spectral response range to realize the full spectrum photocatalysis is crucial to develop photocatalysts with satisfactory light-energy conversion ability.A full-spectrum driven p-n heterojunction photocata...Broadening spectral response range to realize the full spectrum photocatalysis is crucial to develop photocatalysts with satisfactory light-energy conversion ability.A full-spectrum driven p-n heterojunction photocatalytic system was rationally designed through introducing the Er^(3+)/Yb^(3+)co-doped BiOBr with up-conversion effect as the collector of near infrared light and photocatalysts substrate.Meanwhile,Cu_(3)Mo_(2)O_(9) with the photothermal effect as a heat source to accelerate the reaction at the surface through absorbing the near infrared light.The photocatalytic activity of BiOBr:Yb^(3+),Er^(3+)/Cu3Mo2O9 composite was markedly strengthened under visible and near infrared light irradiation,and the BiOBr:Yb^(3+),Er^(3+)/Cu_(3)Mo_(2)O_(9)-5 composite displayed the optimal photodegradation activities for 0.03372 min^(-1) and 0.058 h^(-1),being 2.3-folds and 2.4-folds than that of pure BiOBr:Yb^(3+),Er^(3+)under the visible and near infrared light,respectively.The position of doped ions(Yb^(3+)and Er^(3+))in BiOBr:Yb^(3+),Er^(3+)was determined from the X-ray absorption fine structure spectra.And the reasonable mechanism of p-n heterojunction was proposed base on the results of experimental and density functional theory calculation.This work provides a rational strategy for the design and development of full-spectrum heterojunction photocatalysts with the up-conversion and photothermal effects to increase the photocatalytic performance.展开更多
The artificial photosynthesis technology has been recognized as a promising solution for CO_(2) utilization.Photothermal catalysis has been proposed as a novel strategy to promote the efficiency of artificial photosyn...The artificial photosynthesis technology has been recognized as a promising solution for CO_(2) utilization.Photothermal catalysis has been proposed as a novel strategy to promote the efficiency of artificial photosynthesis by coupling both photochemistry and thermochemistry.However,strategies for maximizing the use of solar spectra with different frequencies in photothermal catalysis are urgently needed.Here,a hierarchical full-spectrum solar light utilization strategy is proposed.Based on this strategy,a Cu@hollow titanium silicalite-1 zeolite(TS-1)nanoreactor with spatially separated photo/thermal catalytic sites is designed to realize high-efficiency photothermal catalytic artificial photosynthesis.The space-time yield of alcohol products over the optimal catalyst reached 64.4μmol g−1 h−1,with the selectivity of CH3CH2OH of 69.5%.This rationally designed hierarchical utilization strategy for solar light can be summarized as follows:(1)high-energy ultraviolet light is utilized to drive the initial and difficult CO_(2) activation step on the TS-1 shell;(2)visible light can induce the localized surface plasmon resonance effect on plasmonic Cu to generate hot electrons for H2O dissociation and subsequent reaction steps;and(3)low-energy near-infrared light is converted into heat by the simulated greenhouse effect by cavities to accelerate the carrier dynamics.This work provides some scientific and experimental bases for research on novel,highly efficient photothermal catalysts for artificial photosynthesis.展开更多
Fluidization technology has been used in CO_(2) capture processes, the successful design and operation of the heat exchangers involved in this process require much information on the bed-to-wall heat transfer of the s...Fluidization technology has been used in CO_(2) capture processes, the successful design and operation of the heat exchangers involved in this process require much information on the bed-to-wall heat transfer of the sorbent particles in fluidized states. In this study, the bed-to-wall heat transfer coefficient (h) of a solid amine sorbent was measured by a heat transfer probe in a large-scale circulating fluidized bed cold model unit, where full spectrum of fluidization regimes can be realized. The corresponding hydrodynamic signals were also studied by pressure sensors and optical fiber probes to further explain the newly discovered phenomenon. The results show that in a dense bed, due to the counterbalanced effect of time fraction of packet and packet renewal frequency, h of the Geldart B particle reaches a peak within the bubbling fluidized regime, and the radial distribution of h are opposite in bubbling and turbulent fluidized regimes. In a fast fluidization regime, gas convection becomes the dominant factor affecting h when the solids holdup is low enough. Correlations were provided or recommended to guide the design of heat exchangers in the fluidized bed CO_(2) capture processes.展开更多
Transmission error(TE)in geared rotors is a predominant source of inherent excitation at the pitch point of the gear meshing.In this paper,a transverse vibration analysis is presented to study the effect of TE on gear...Transmission error(TE)in geared rotors is a predominant source of inherent excitation at the pitch point of the gear meshing.In this paper,a transverse vibration analysis is presented to study the effect of TE on geared rotors.Due to asymmetry in the TE,it is expected to have both forward and backward whirls excited during rotor whirling,which could be used for its detection.This aspect has been envisioned first time in the present work.To capture this,an approach of orienting the line of action of a gear-pair along oblique plane is considered and the mathematical modeling has been performed of a simple spur gear-pair connecting two parallel shafts at its mid-span with an asymmetric TE.To capture the forward and backward whirls,equations of motion are converted into a complex form that facilitates obtaining response in full spectrum.The response of system model with assumed transmission error and gear-pair parameters has been obtained through a numerical simulation,which shows distinctly the forward and backward whirls due to the TE.Through a simple test rig experimentation,a similar behaviour was observed in transverse vibrations of geared rotors in the full spectrum,which validate the proposed model.展开更多
The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectr...The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.展开更多
基金supported by Shandong Provincial Natural Science Foundation,China(Grant Nos.ZR2022ME179,ZR2021QE086)Liaocheng Key Research and Development Program(Policy Guidance Category)(Grant No.2022YDSF89)+1 种基金Liaocheng University Innovation and Entrepreneurship Training Program for College Students(Grant No.2020205963)the 4B9A station of the Beijing Synchrotron Radiation Facility(BSRF).
文摘Broadening spectral response range to realize the full spectrum photocatalysis is crucial to develop photocatalysts with satisfactory light-energy conversion ability.A full-spectrum driven p-n heterojunction photocatalytic system was rationally designed through introducing the Er^(3+)/Yb^(3+)co-doped BiOBr with up-conversion effect as the collector of near infrared light and photocatalysts substrate.Meanwhile,Cu_(3)Mo_(2)O_(9) with the photothermal effect as a heat source to accelerate the reaction at the surface through absorbing the near infrared light.The photocatalytic activity of BiOBr:Yb^(3+),Er^(3+)/Cu3Mo2O9 composite was markedly strengthened under visible and near infrared light irradiation,and the BiOBr:Yb^(3+),Er^(3+)/Cu_(3)Mo_(2)O_(9)-5 composite displayed the optimal photodegradation activities for 0.03372 min^(-1) and 0.058 h^(-1),being 2.3-folds and 2.4-folds than that of pure BiOBr:Yb^(3+),Er^(3+)under the visible and near infrared light,respectively.The position of doped ions(Yb^(3+)and Er^(3+))in BiOBr:Yb^(3+),Er^(3+)was determined from the X-ray absorption fine structure spectra.And the reasonable mechanism of p-n heterojunction was proposed base on the results of experimental and density functional theory calculation.This work provides a rational strategy for the design and development of full-spectrum heterojunction photocatalysts with the up-conversion and photothermal effects to increase the photocatalytic performance.
基金supported by the National Natural Science Foundation of China(Grant Nos.21908052 and 22108200)the Key Program of the Natural Science Foundation of Hebei Province(Grant No.B2020209017)+2 种基金the Project of Science and Technology Innovation Team,Tangshan(Grant No.20130203D)the Natural Science Foundation of Zhejiang Province(Grant No.LQ22B060013)and the Science and Technology Project of Hebei Education Department(Grant No.QN2021113).
文摘The artificial photosynthesis technology has been recognized as a promising solution for CO_(2) utilization.Photothermal catalysis has been proposed as a novel strategy to promote the efficiency of artificial photosynthesis by coupling both photochemistry and thermochemistry.However,strategies for maximizing the use of solar spectra with different frequencies in photothermal catalysis are urgently needed.Here,a hierarchical full-spectrum solar light utilization strategy is proposed.Based on this strategy,a Cu@hollow titanium silicalite-1 zeolite(TS-1)nanoreactor with spatially separated photo/thermal catalytic sites is designed to realize high-efficiency photothermal catalytic artificial photosynthesis.The space-time yield of alcohol products over the optimal catalyst reached 64.4μmol g−1 h−1,with the selectivity of CH3CH2OH of 69.5%.This rationally designed hierarchical utilization strategy for solar light can be summarized as follows:(1)high-energy ultraviolet light is utilized to drive the initial and difficult CO_(2) activation step on the TS-1 shell;(2)visible light can induce the localized surface plasmon resonance effect on plasmonic Cu to generate hot electrons for H2O dissociation and subsequent reaction steps;and(3)low-energy near-infrared light is converted into heat by the simulated greenhouse effect by cavities to accelerate the carrier dynamics.This work provides some scientific and experimental bases for research on novel,highly efficient photothermal catalysts for artificial photosynthesis.
基金support by the National Natural Science Foundation of China(grant No.21808245).
文摘Fluidization technology has been used in CO_(2) capture processes, the successful design and operation of the heat exchangers involved in this process require much information on the bed-to-wall heat transfer of the sorbent particles in fluidized states. In this study, the bed-to-wall heat transfer coefficient (h) of a solid amine sorbent was measured by a heat transfer probe in a large-scale circulating fluidized bed cold model unit, where full spectrum of fluidization regimes can be realized. The corresponding hydrodynamic signals were also studied by pressure sensors and optical fiber probes to further explain the newly discovered phenomenon. The results show that in a dense bed, due to the counterbalanced effect of time fraction of packet and packet renewal frequency, h of the Geldart B particle reaches a peak within the bubbling fluidized regime, and the radial distribution of h are opposite in bubbling and turbulent fluidized regimes. In a fast fluidization regime, gas convection becomes the dominant factor affecting h when the solids holdup is low enough. Correlations were provided or recommended to guide the design of heat exchangers in the fluidized bed CO_(2) capture processes.
文摘Transmission error(TE)in geared rotors is a predominant source of inherent excitation at the pitch point of the gear meshing.In this paper,a transverse vibration analysis is presented to study the effect of TE on geared rotors.Due to asymmetry in the TE,it is expected to have both forward and backward whirls excited during rotor whirling,which could be used for its detection.This aspect has been envisioned first time in the present work.To capture this,an approach of orienting the line of action of a gear-pair along oblique plane is considered and the mathematical modeling has been performed of a simple spur gear-pair connecting two parallel shafts at its mid-span with an asymmetric TE.To capture the forward and backward whirls,equations of motion are converted into a complex form that facilitates obtaining response in full spectrum.The response of system model with assumed transmission error and gear-pair parameters has been obtained through a numerical simulation,which shows distinctly the forward and backward whirls due to the TE.Through a simple test rig experimentation,a similar behaviour was observed in transverse vibrations of geared rotors in the full spectrum,which validate the proposed model.
基金supported by the National Key R&D Project of China(No.2017YFC0602100)the National Natural Science Foundation of China(No.41774147)Sichuan Science and Technology Support Program(No.2015GZ0272)
文摘The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.
文摘应用全光谱测量水体化学需氧量(chemical oxygen demand,COD)、硝酸盐氮(NO_(3)-N)浓度等水环境质量指标容易受水质环境影响,检测模型与特征波长一直是全光谱检测推广关注重点。该文提出一种基于遗传算法-径向基神经网络(genetic algorithm-radial basis function neural network,GA-RBFNN)全光谱水体COD与NO_(3)-N浓度检测方法,鉴于GA搜索能力强、随机性高的特点,对预处理后全光谱吸收数据应用GA进行特征波长选取,以RBFNN神经网络留K法训练过程中平均决定系数作为适应度函数,输出最优特征波长与RBFNN神经网络参数进行部署,从而实现水体COD、NO_(3)-N浓度准确测量。最后,开展GA-RBFNN、偏最小二乘(partial least squares,PLS)、GA-PLS、RBFNN四种模型对160组水样的COD、NO_(3)-N浓度检测实验,结果表明GA-RBFNN模型对COD、NO_(3)-N检测平均决定系数、最大误差分别为0.9964、0.9950和3.9%、4.9%,均优于其他模型,方法具有重要推广价值。
