A high Si reduced activation ferritic/martensitic(RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr10.0–10.5%,...A high Si reduced activation ferritic/martensitic(RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr10.0–10.5%, W 1.0–1.5%, Si 1.0–1.3%, V+Ta 0.30–0.45%, and Fe in balance. High Si design brings excellent corrosion resistance, while low activation is advantageous in the nuclear waste processing. The experimental results indicate that the newly designed high Si RAFM steel had full martensitic structure and uniformly distributed fine second phase particles, and exhibited excellent mechanical properties and corrosion resistance. Compared to the P91 steel, this new RAFM steel designed by Calphad method is expected to be a promising candidate used in nuclear power generation, which also provides a new and effective approach to the development of RAFM steel for nuclear application.展开更多
Natural gas hydrate(NGH)has a bright future as a clean energy source with huge reserves.Coring is one of the most direct methods for NGH exploration and research.Preserving the in-situ properties of the core as much a...Natural gas hydrate(NGH)has a bright future as a clean energy source with huge reserves.Coring is one of the most direct methods for NGH exploration and research.Preserving the in-situ properties of the core as much as possible during the coring process is crucial for the assessment of NGH resources.However,most existing NGH coring techniques cannot preserve the in-situ temperature of NGH,leading to distortion of the physical properties of the obtained core,which makes it difficult to effectively guide NGH exploration and development.To overcome this limitation,this study introduces an innovative active temperature-preserved coring method for NGH utilizing phase change materials(PCM).An active temperature-preserved corer(ATPC)is designed and developed,and an indoor experimental system is established to investigate the heat transfer during the coring process.Based on the experimental results under different environment temperatures,a heat transfer model for the entire ATPC coring process has been established.The indoor experimental results are consistent with the theoretical predictions of the heat transfer model,confirming its validity.This model has reconstructed the temperature changes of the NGH core during the coring process,demonstrating that compared to the traditional coring method with only passive temperature-preserved measures,ATPC can effectively reduce the core temperature by more than 5.25℃.With ATPC,at environment temperatures of 15,20,25,and 30℃,the duration of low-temperature state for the NGH core is 53.85,32.87,20.32,and 11.83 min,respectively.These findings provide new perspectives on temperature-preserving core sampling in NGH and provide technical support for exploration and development in NGH.展开更多
According to the chemical and mineral composition characteristics of the fly ash,alumina can be extracted from fly ash through the calcining method by using sodium carbonate and calcium carbonate additives.The effects...According to the chemical and mineral composition characteristics of the fly ash,alumina can be extracted from fly ash through the calcining method by using sodium carbonate and calcium carbonate additives.The effects on leaching rate of alumina have been investigated. The results showed that the fly ash can be activated effectively and the leaching rate of alumina can be improved to more than 92% through this method. The best process parameters were the ratio of raw materials,i. e. the material weight ratio of fly ash,calcium carbonate and sodium carbonate was 1. 0∶1. 2∶0. 9. The activating temperature was 850℃-900℃,activating time was 3 h. This process has a potential application prospect and improves the value of comprehensive utilization of fly ash.展开更多
This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement tech...This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement technique,which is used in Civil Engineering applications to produce calcium carbonate through bacterial or enzymatic activity,replacing the use of other binder materials such as cement or resins,and therefore reducing carbon footprint.The microdevice was used to measure urease activity in the soil interstitial fluid,to investigate if bacterial activity could be affected by the presence of the particles and tortuosity from pore geometry.Such analysis is important to understand biocementation mechanism inside the soil and helps to improve the design of such treatment solutions.The device is basically a squared reservoir printed in polypropylene using a 3D printing machine,incorporating stainless steel electrodes in its base.The electrical resistivity was computed adopting Wenner method,by connecting 4 PCB electrodes to a signal generator and an oscilloscope for measuring the voltage when a AC current of 1 mA was applied.Both square and sinusoidal waves with 5 kHz frequency were selected among other frequencies.The measurements were adjusted during the calibration of the microdevice,done using standard salt solutions with known electrical conductivity measured using an electrical conductivity probe.For the bacterial activity measurements,the bacterial and urea solutions were added to a uniform-graded size quarzitic sand(average diameter 0.3 mm)placed inside the microdevice and covering completely the electrodes.Bacterial activity was not affected by the presence of the sand,which confirms that this treatment is effective for this type of soils.展开更多
The traditional detailed model of the dual active bridge(DAB)power electronic transformer is characterized by the high dimensionality of its nodal admittance matrix and the need for a small simulation step size,which ...The traditional detailed model of the dual active bridge(DAB)power electronic transformer is characterized by the high dimensionality of its nodal admittance matrix and the need for a small simulation step size,which limits the speed of electromagnetic transient(EMT)simulations.To overcome these limitations,a novel EMT equivalent model based on a generalized branch-cutting method is proposed to improve the simulation efficiency of the DAB model.The DAB topology is first decomposed into two subnetworks through branch-cutting and node-tearing methods without the introduction of a one-time-step delay.Sub-sequently,the internal nodes of each sub-network are eliminated through network simplification,and the equivalent circuit for the port cascade module is derived.The model is then validated through simulations across various operating conditions.The results demonstrate that the model avoids the loss of accuracy associated with one-time-step delay,the relative error across different conditions remains below 1%,and the simulation acceleration ratios improve as the number of modules increases.展开更多
Recent years have witnessed significant advances in the development of novel techniques and methodologies for identifying active ingredients in traditional Chinese medicine(TCM),substantially advancing research and de...Recent years have witnessed significant advances in the development of novel techniques and methodologies for identifying active ingredients in traditional Chinese medicine(TCM),substantially advancing research and development efforts.Spectrum-effect correlation analysis,affinity ultrafiltration,high-content screening(HCS)imaging,and cell membrane chromatography(CMC)have emerged as essential tools,effectively linking TCM chemical constituents to their biological effects,thereby enabling efficient active ingredient screening.Additionally,molecular interaction analysis provides deeper insights into TCM-biomolecule interaction mechanisms,enhancing understanding of its therapeutic potential.Computer-aided techniques facilitate TCM active ingredient identification,optimizing the screening process for efficiency and cost-effectiveness.Molecular probe technology,as an emerging methodology,enables precise and rapid screening for novel therapeutic drug discovery.Ongoing technological advancement in this field indicates promising future developments,potentially leading to more effective and targeted TCM-based therapies.展开更多
A new method of NAA for sediment movement study is presented in this paper. Through analyzing the natural sediment, the information about natural tracing agents has been obtained, which can show the direction of sedim...A new method of NAA for sediment movement study is presented in this paper. Through analyzing the natural sediment, the information about natural tracing agents has been obtained, which can show the direction of sediment movement and relative discharge of sediment transportation. Test results in some areas, such as Shantou Harbour and Hangzhou Bay, are in good agreement with those from normal hydrologic measurements and some results are not obtainable with the latter. The NAA is economical, practical and reliable, and should be widely used in engineering practice.展开更多
Purpose–The efficient utilization of recycled concrete powder(RCP)has attracted much attention.To break through the limitation of single activation technology of RCP,this study investigates the effects of a mechanica...Purpose–The efficient utilization of recycled concrete powder(RCP)has attracted much attention.To break through the limitation of single activation technology of RCP,this study investigates the effects of a mechanical-microwave method on the reactivity of RCP.Design/methodology/approach–The mechanical properties,hydration products,and pore structure of RCP-incorporated mortar were evaluated.Findings–The results demonstrate that the combined activation reduces the median particle size of RCP and induces a low-frequency shift in the Si-O-T FT-IR characteristic peaks,signifying depolymerization of the silicate network and formation of highly reactive broken bond sites.Concurrently,decreased Si2p and Al2p binding energies in XPS spectra confirm enhanced surface reactivity.The 28-day strength activity index(SAI)of RCP mortar improved from 65.7(untreated)to 82.2%under optimal activation conditions(90-min ball milling followed by 10-min microwave irradiation),outperforming solely mechanical activation by 3.6–6.1%.Furthermore,combined activation increased chemically bound water content from 22.8 to 33.7%,accompanied by a low-wavenumber shift in FT-IR peaks of hydration products.The total porosity of RCP mortar decreased from 17.2 to 14.6%,indicating a denser pore structure.Originality/value–This study explores the feasibility and potential mechanism of mechanical-microwave activation of RCP,aiming to provide valuable insights for the sustainable development of materials.Using activated RCP in cement-based materials reduces the demand for cement and substantially cuts carbon emissions,thereby making a critical contribution to the construction industry’s green and low-carbon transition.展开更多
Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and...Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and released into the atmosphere.Activated tungsten migrates downward in the soil after atmospheric deposition.However,effective methods for evaluating the environmental dose of gamma rays emitted by activated tungsten are still lacking.Consequently,a method for evaluating the air-absorbed dose rate of activated tungsten dust was proposed considering soil attenuation.Key parameters including the mass attenuation coefficient and energy absorption build-up factor were determined for the main gamma ray energies of radionuclides within the activated tungsten dust.Additionally,air-absorbed dose rates were calculated by assuming that radioactive sources were located at different soil depths and radii.It was found that a soil depth of 50 cm significantly attenuated the environmental dose by 99.9%,whereas the air-absorbed dose rates within the horizontal distance of 500 cm accounted for 91%of the total dose rate.Therefore,this study underscored the importance of soil attenuation in environmental dose assessments,which must be carefully re-examined for the safety analysis of fusion reactors.展开更多
By measuring and analyzing the crystallization activation energy (CAE) of Fe-based amorphous alloy Fe79B16Si5 and Fe78B13Si9, it is reconfirmed and further analyzed that the conventional Kissinger method does not conf...By measuring and analyzing the crystallization activation energy (CAE) of Fe-based amorphous alloy Fe79B16Si5 and Fe78B13Si9, it is reconfirmed and further analyzed that the conventional Kissinger method does not conform with the premise of Kissinger equation, namely, samples with different heating rates should keep a constant fraction of transformation at the exothermal peak temperature Tp of DSC thermogram. The XRD equal first peak height (EFPH) method is applied to CAE measurement of Fe-based amorphous alloy for the first time. It is shown again that the EFPH method coincides with the premise of Kissinger equation. The procedure of EFPH method is introduced in detail in this paper. The accuracy in determining CAE of amorphous alloy may be improved by applying the EFPH method. As a result, the mechanism of embrittlement of amorphous alloy may be better elucidated.展开更多
This paper investigates the active traveling wave vibration control of an elastic supported rotating porous aluminium conical shell(CS)under impact loading.Piezoelectric smart materials in the form of micro fiber comp...This paper investigates the active traveling wave vibration control of an elastic supported rotating porous aluminium conical shell(CS)under impact loading.Piezoelectric smart materials in the form of micro fiber composites(MFCs)are used as actuators and sensors.To this end,a metal pore truncated CS with MFCs attached to its surface is considered.Adding artificial virtual springs at two edges of the truncated CS achieves various elastic supported boundaries by changing the spring stiffness.Based on the first-order shear deformation theory(FSDT),minimum energy principle,and artificial virtual spring technology,the theoretical formulations considering the electromechanical coupling are derived.The comparison of the natural frequency of the present results with the natural frequencies reported in previous literature evaluates the accuracy of the present approach.To study the vibration control,the integral quadrature method in conjunction with the differential quadrature approximation in the length direction is used to discretize the partial differential dynamical system to form a set of ordinary differential equations.With the aid of the velocity negative feedback method,both the time history and the input control voltage on the actuator are demonstrated to present the effects of velocity feedback gain,pore distribution type,semi-vertex angle,impact loading,and rotational angular velocity on the traveling wave vibration control.展开更多
For nonlinear stability problems of discretized conservative systems with multiple parameter variables and multiple state variables, the activation method is put forward, by which activated potential functions and act...For nonlinear stability problems of discretized conservative systems with multiple parameter variables and multiple state variables, the activation method is put forward, by which activated potential functions and activated equilibrium equations are derived. The activation method is the improvement and enhancement of Liapunov-Schmidt method in elastic stability theory. It is more generalized and more normalized than conventional perturbation methods. The activated potential functions may be transformed into normalized catastrophe potential functions. The activated equilibrium equations may be treated as bifurcation equations. The researches in this paper will motivate the combination of elastic stability theory with catastrophe theory and bifurcation theory展开更多
In this study, the activation cross-sections were measured for ^(232)Th(n,2n)^(231)Th reactions at neutron energies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n)~4He reaction. Induc...In this study, the activation cross-sections were measured for ^(232)Th(n,2n)^(231)Th reactions at neutron energies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n)~4He reaction. Induced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. In the cross-section calculations, corrections were made regarding the effects of gamma-ray attenuation, dead-time, fluctuation of the neutron flux, and low energy neutrons. The measured cross-sections were compared with the literature data, evaluation data(ENDF-B/VII.1, JENDL-4.0 and CENDL-3.1), and the results of the model calculation(TALYS1.6).展开更多
This study explores the complex dynamics of unsteady convective flow in micropolar nanofluids over a rough conical surface, with a focus on the effects of triple diffusive transport and Arrhenius activation energy. Th...This study explores the complex dynamics of unsteady convective flow in micropolar nanofluids over a rough conical surface, with a focus on the effects of triple diffusive transport and Arrhenius activation energy. The primary objective is to understand the interplay among nonlinear convection, micro-rotation effects, and species diffusion under the influence of thermal and electromagnetic forces. The analysis is motivated by practical applications of cryogenic fluids, specifically liquid hydrogen and liquid nitrogen,where precise control of heat and mass transport is critical. The conical surface roughness is mathematically modeled as a high-frequency, small-amplitude sinusoidal waveform.To address the non-similar nature of the boundary-layer equations, Mangler's transformations are employed, followed by the implementation of a finite difference scheme for numerical solutions. The methodology further integrates a machine learning-based neural network to predict the skin friction under the influence of roughness-induced perturbations, ensuring computational efficiency and improved generalization. The study yields several novel findings. Notably, the presence of surface roughness introduces the wavelike modulations in the local skin friction coefficient. It is also observed that nonlinear convective interactions, enhanced by temperature gradients and vortex viscosity parameters, significantly intensify near-wall velocity gradients. Moreover, key physical quantities are correlated with governing parameters using power-law relationships, providing generalized predictive models. The validation of the numerical results is achieved through consistency checks with the existing limiting solutions and convergence analysis, ensuring the reliability of the proposed computational framework.展开更多
In 2025,I had the honor of delivering keynote speeches at the conferences of the International Society for Diet and Activity Methods in Toronto,Canada,and the International Society of Behavioural Nutrition and Physica...In 2025,I had the honor of delivering keynote speeches at the conferences of the International Society for Diet and Activity Methods in Toronto,Canada,and the International Society of Behavioural Nutrition and Physical Activity in Auckland,Aotearoa,New Zealand.These opportunities prompted deep reflection on scientific research in general,and on physical activity and health research specifically.展开更多
As a novel class of purely organic fluores-cent materials,multiple resonance thermal-ly activated delayed fluorescence(MR-TADF)compounds hold significant promise for next-generation display technologies.The efficiency...As a novel class of purely organic fluores-cent materials,multiple resonance thermal-ly activated delayed fluorescence(MR-TADF)compounds hold significant promise for next-generation display technologies.The efficiency of exciton utilization and the overall performance of organic light-emit-ting devices are closely linked to the singlet-triplet energy gap(ΔE_(ST))of MR-TADF emitters.Identifying an economic and accu-rate theoretical approach to predictΔE_(ST)would be beneficial for high-throughput screening and facilitate the inverse design of MR-TADF molecules.In this study,we evaluated the S_(1)state energy(E(S_(1))),T_(1)state ener-gy(E(T_(1))),andΔE_(ST)using three different physical interpretations:adiabatic excitation ener-gy,vertical absorption energy,and vertical emission energy.We employed the time-depen-dent density functional theory(TDDFT)and delta self-consistent field(ΔSCF)methods to calculate E(S_(1)),E(T_(1)),andΔE_(ST)for 20 MR-TADF molecules reported in the literature.We compared these calculated values with experimental data obtained from fluorescence spec-troscopy at room-temperature(or 77 K)and phosphorescence spectroscopy conducted at 77 K.Our findings indicate that the vertical absorption energy at the S0 state minimum,deter-mined by theΔSCF method,accurately predicts the S_(1)state energy.Similarly,the vertical absorption energy at the S0 state minimum,calculated using the TDDFT method,effectively predicts the T_(1)state energy.TheΔE_(ST)derived from the difference between these two excita-tion energies exhibited the smallest mean absolute error of only 0.039 eV compared to the ex-perimental values.This combination represents the most accurate and cost-effective method reported to date for predicting theΔE_(ST)of MR-TADF molecules,and can be integrated into AI-driven inverse design workflows for new emitters.展开更多
The component synthesis active vibration suppression method （CSVS） can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according...The component synthesis active vibration suppression method （CSVS） can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according to certain rules along the time axis. The synthesized command can suppress the arbitrary unwanted vibration harmonic while achieving the desired rigid body motion. The number of the components increases rapidly when the number of harmonic vibration is growing. In this article, the CSVS based on zero-placement technique is used to construct the synthesized command to suppress the multi-harmonics simultaneously in the discrete domain. The nature of zero-placement method is to put enough zeros to cancel system poles at necessary points. The designed synthesized command has equal time intervals between each component and which is much easier to be implemented. Using this method, the number of components increases linearly with the increasing of the number of being suppressed harmonics. For the spacecraft with flexible appendages, CSVS based on zero-placement is used to design the time optimal large angle maneuver control strategy. Simulations have verified the validity and superiority of the proposed approach.展开更多
[Objective] This paper aimed at exploring the effects of different nitrogen application methods on the enzyme activities of leaves at ear position in late growth stage of maize. [Method] By pot experiment, the superox...[Objective] This paper aimed at exploring the effects of different nitrogen application methods on the enzyme activities of leaves at ear position in late growth stage of maize. [Method] By pot experiment, the superoxide dismutase （SOD） activity, peroxidase （POD） activity, malonyl dialdehyde （MDA） content and soluble protein content were determined. [Result] At the filling stage and ripening stage, with the increasing of nitrogen application rate, MDA content gradually decreased, while SOD activity, POD activity and soluble protein content increased. MDA content with two topdressing nitrogen was lower than that with one top dressing nitrogen at the same nitrogen application rate, while SOD activity, POD activity and soluble protein content with two topdressing nitrogen were higher than that with one topdressing nitrogen. [Conclusion] Different nitrogen application methods have relatively significant effects on the MDA content, SOD activity, POD activity and soluble protein content, which is of certain directive significance for preventing spring maize prematuration.展开更多
The objective of this study was to evaluate the effects of wheat variety, food processing, and milling method on antioxidant properties. Black wheat variety Heibaoshi 1 had the highest total phenolic content(659.8 μg...The objective of this study was to evaluate the effects of wheat variety, food processing, and milling method on antioxidant properties. Black wheat variety Heibaoshi 1 had the highest total phenolic content(659.8 μg gallic acid equivalents g-1), total flavonoid content(319.3 μg rutin equivalents g-1), and antioxidant activity, whereas light purple wheat variety Shandongzimai 1 had the lowest total flavonoid content(236.2 μg rutin equivalents g-1) and antioxidant activity. Whole wheat flour and partially debranned grain flour had significantly higher total phenolic contents, total flavonoid contents, and antioxidant activity than refined flour(P < 0.05). Compared with flour, total phenolic contents, total flavonoid contents and antioxidant activity decreased in noodles and steamed bread, whereas noodles had slightly higher total phenolic and flavonoid content than steamed bread. Antioxidant activities(by ferric reducing ability of plasma assay) of steamed bread made from whole wheat flour, partially debranned grain flour, and refined flour were 23.5%, 21.1%, and 31.6% lower, respectively, than the corresponding values of flour. These results suggested that black whole wheat flour and partially debranned grain flour are beneficial to human health.展开更多
基金supported by "Excellent Scholar Funding" with the title of "R&D on advanced structural steels in new nuclear energy system" initialed by Institute for Materials Research, Chinese Academy (grant number: Y7A7A111A1)
文摘A high Si reduced activation ferritic/martensitic(RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr10.0–10.5%, W 1.0–1.5%, Si 1.0–1.3%, V+Ta 0.30–0.45%, and Fe in balance. High Si design brings excellent corrosion resistance, while low activation is advantageous in the nuclear waste processing. The experimental results indicate that the newly designed high Si RAFM steel had full martensitic structure and uniformly distributed fine second phase particles, and exhibited excellent mechanical properties and corrosion resistance. Compared to the P91 steel, this new RAFM steel designed by Calphad method is expected to be a promising candidate used in nuclear power generation, which also provides a new and effective approach to the development of RAFM steel for nuclear application.
基金financially supported by Shenzhen Science and Technology Program(Nos.JSGG20220831105002005 and KJZD20231025152759002)the National Natural Science Foundation of China(Nos.52274133 and 523B2101).
文摘Natural gas hydrate(NGH)has a bright future as a clean energy source with huge reserves.Coring is one of the most direct methods for NGH exploration and research.Preserving the in-situ properties of the core as much as possible during the coring process is crucial for the assessment of NGH resources.However,most existing NGH coring techniques cannot preserve the in-situ temperature of NGH,leading to distortion of the physical properties of the obtained core,which makes it difficult to effectively guide NGH exploration and development.To overcome this limitation,this study introduces an innovative active temperature-preserved coring method for NGH utilizing phase change materials(PCM).An active temperature-preserved corer(ATPC)is designed and developed,and an indoor experimental system is established to investigate the heat transfer during the coring process.Based on the experimental results under different environment temperatures,a heat transfer model for the entire ATPC coring process has been established.The indoor experimental results are consistent with the theoretical predictions of the heat transfer model,confirming its validity.This model has reconstructed the temperature changes of the NGH core during the coring process,demonstrating that compared to the traditional coring method with only passive temperature-preserved measures,ATPC can effectively reduce the core temperature by more than 5.25℃.With ATPC,at environment temperatures of 15,20,25,and 30℃,the duration of low-temperature state for the NGH core is 53.85,32.87,20.32,and 11.83 min,respectively.These findings provide new perspectives on temperature-preserving core sampling in NGH and provide technical support for exploration and development in NGH.
文摘According to the chemical and mineral composition characteristics of the fly ash,alumina can be extracted from fly ash through the calcining method by using sodium carbonate and calcium carbonate additives.The effects on leaching rate of alumina have been investigated. The results showed that the fly ash can be activated effectively and the leaching rate of alumina can be improved to more than 92% through this method. The best process parameters were the ratio of raw materials,i. e. the material weight ratio of fly ash,calcium carbonate and sodium carbonate was 1. 0∶1. 2∶0. 9. The activating temperature was 850℃-900℃,activating time was 3 h. This process has a potential application prospect and improves the value of comprehensive utilization of fly ash.
基金FCT I.P,for the funding through CALCITE Project(ref.PTDC/ECI-EGC/1086/2021).
文摘This paper presents a microdevice developed to measure the electrical conductivity of a liquid or a saturated porous medium using Wenner method.It is developed in the context of biocementation as soil improvement technique,which is used in Civil Engineering applications to produce calcium carbonate through bacterial or enzymatic activity,replacing the use of other binder materials such as cement or resins,and therefore reducing carbon footprint.The microdevice was used to measure urease activity in the soil interstitial fluid,to investigate if bacterial activity could be affected by the presence of the particles and tortuosity from pore geometry.Such analysis is important to understand biocementation mechanism inside the soil and helps to improve the design of such treatment solutions.The device is basically a squared reservoir printed in polypropylene using a 3D printing machine,incorporating stainless steel electrodes in its base.The electrical resistivity was computed adopting Wenner method,by connecting 4 PCB electrodes to a signal generator and an oscilloscope for measuring the voltage when a AC current of 1 mA was applied.Both square and sinusoidal waves with 5 kHz frequency were selected among other frequencies.The measurements were adjusted during the calibration of the microdevice,done using standard salt solutions with known electrical conductivity measured using an electrical conductivity probe.For the bacterial activity measurements,the bacterial and urea solutions were added to a uniform-graded size quarzitic sand(average diameter 0.3 mm)placed inside the microdevice and covering completely the electrodes.Bacterial activity was not affected by the presence of the sand,which confirms that this treatment is effective for this type of soils.
基金The Technology Project of State Grid Corporation of China Headquarters(No.5400-202318547A-3-2-ZN).
文摘The traditional detailed model of the dual active bridge(DAB)power electronic transformer is characterized by the high dimensionality of its nodal admittance matrix and the need for a small simulation step size,which limits the speed of electromagnetic transient(EMT)simulations.To overcome these limitations,a novel EMT equivalent model based on a generalized branch-cutting method is proposed to improve the simulation efficiency of the DAB model.The DAB topology is first decomposed into two subnetworks through branch-cutting and node-tearing methods without the introduction of a one-time-step delay.Sub-sequently,the internal nodes of each sub-network are eliminated through network simplification,and the equivalent circuit for the port cascade module is derived.The model is then validated through simulations across various operating conditions.The results demonstrate that the model avoids the loss of accuracy associated with one-time-step delay,the relative error across different conditions remains below 1%,and the simulation acceleration ratios improve as the number of modules increases.
基金supported by the National Natural Science Foundation of China (Nos. 22175078, 52373287, 82404846, and 22467002)the Natural Science Foundation of Jiangsu Province of China (No. BK20241597)the Fundamental Research Funds for the Central Universities (No. 2632024TD05)
文摘Recent years have witnessed significant advances in the development of novel techniques and methodologies for identifying active ingredients in traditional Chinese medicine(TCM),substantially advancing research and development efforts.Spectrum-effect correlation analysis,affinity ultrafiltration,high-content screening(HCS)imaging,and cell membrane chromatography(CMC)have emerged as essential tools,effectively linking TCM chemical constituents to their biological effects,thereby enabling efficient active ingredient screening.Additionally,molecular interaction analysis provides deeper insights into TCM-biomolecule interaction mechanisms,enhancing understanding of its therapeutic potential.Computer-aided techniques facilitate TCM active ingredient identification,optimizing the screening process for efficiency and cost-effectiveness.Molecular probe technology,as an emerging methodology,enables precise and rapid screening for novel therapeutic drug discovery.Ongoing technological advancement in this field indicates promising future developments,potentially leading to more effective and targeted TCM-based therapies.
文摘A new method of NAA for sediment movement study is presented in this paper. Through analyzing the natural sediment, the information about natural tracing agents has been obtained, which can show the direction of sediment movement and relative discharge of sediment transportation. Test results in some areas, such as Shantou Harbour and Hangzhou Bay, are in good agreement with those from normal hydrologic measurements and some results are not obtainable with the latter. The NAA is economical, practical and reliable, and should be widely used in engineering practice.
基金sponsored by Science and Technology Research and Development Plan of China National Railway Group Co.,Ltd.(L2022G009)National Natural Science Foundation of China(52438002)+1 种基金Research Project of China Academy of Railway Science Corporation Limited(2024YJ254)New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘Purpose–The efficient utilization of recycled concrete powder(RCP)has attracted much attention.To break through the limitation of single activation technology of RCP,this study investigates the effects of a mechanical-microwave method on the reactivity of RCP.Design/methodology/approach–The mechanical properties,hydration products,and pore structure of RCP-incorporated mortar were evaluated.Findings–The results demonstrate that the combined activation reduces the median particle size of RCP and induces a low-frequency shift in the Si-O-T FT-IR characteristic peaks,signifying depolymerization of the silicate network and formation of highly reactive broken bond sites.Concurrently,decreased Si2p and Al2p binding energies in XPS spectra confirm enhanced surface reactivity.The 28-day strength activity index(SAI)of RCP mortar improved from 65.7(untreated)to 82.2%under optimal activation conditions(90-min ball milling followed by 10-min microwave irradiation),outperforming solely mechanical activation by 3.6–6.1%.Furthermore,combined activation increased chemically bound water content from 22.8 to 33.7%,accompanied by a low-wavenumber shift in FT-IR peaks of hydration products.The total porosity of RCP mortar decreased from 17.2 to 14.6%,indicating a denser pore structure.Originality/value–This study explores the feasibility and potential mechanism of mechanical-microwave activation of RCP,aiming to provide valuable insights for the sustainable development of materials.Using activated RCP in cement-based materials reduces the demand for cement and substantially cuts carbon emissions,thereby making a critical contribution to the construction industry’s green and low-carbon transition.
基金supported by the National Natural Science Foundation of China(No.12375314)。
文摘Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and released into the atmosphere.Activated tungsten migrates downward in the soil after atmospheric deposition.However,effective methods for evaluating the environmental dose of gamma rays emitted by activated tungsten are still lacking.Consequently,a method for evaluating the air-absorbed dose rate of activated tungsten dust was proposed considering soil attenuation.Key parameters including the mass attenuation coefficient and energy absorption build-up factor were determined for the main gamma ray energies of radionuclides within the activated tungsten dust.Additionally,air-absorbed dose rates were calculated by assuming that radioactive sources were located at different soil depths and radii.It was found that a soil depth of 50 cm significantly attenuated the environmental dose by 99.9%,whereas the air-absorbed dose rates within the horizontal distance of 500 cm accounted for 91%of the total dose rate.Therefore,this study underscored the importance of soil attenuation in environmental dose assessments,which must be carefully re-examined for the safety analysis of fusion reactors.
文摘By measuring and analyzing the crystallization activation energy (CAE) of Fe-based amorphous alloy Fe79B16Si5 and Fe78B13Si9, it is reconfirmed and further analyzed that the conventional Kissinger method does not conform with the premise of Kissinger equation, namely, samples with different heating rates should keep a constant fraction of transformation at the exothermal peak temperature Tp of DSC thermogram. The XRD equal first peak height (EFPH) method is applied to CAE measurement of Fe-based amorphous alloy for the first time. It is shown again that the EFPH method coincides with the premise of Kissinger equation. The procedure of EFPH method is introduced in detail in this paper. The accuracy in determining CAE of amorphous alloy may be improved by applying the EFPH method. As a result, the mechanism of embrittlement of amorphous alloy may be better elucidated.
基金Supported by the National Natural Science Foundation of China(Nos.12272056 and 11832002)。
文摘This paper investigates the active traveling wave vibration control of an elastic supported rotating porous aluminium conical shell(CS)under impact loading.Piezoelectric smart materials in the form of micro fiber composites(MFCs)are used as actuators and sensors.To this end,a metal pore truncated CS with MFCs attached to its surface is considered.Adding artificial virtual springs at two edges of the truncated CS achieves various elastic supported boundaries by changing the spring stiffness.Based on the first-order shear deformation theory(FSDT),minimum energy principle,and artificial virtual spring technology,the theoretical formulations considering the electromechanical coupling are derived.The comparison of the natural frequency of the present results with the natural frequencies reported in previous literature evaluates the accuracy of the present approach.To study the vibration control,the integral quadrature method in conjunction with the differential quadrature approximation in the length direction is used to discretize the partial differential dynamical system to form a set of ordinary differential equations.With the aid of the velocity negative feedback method,both the time history and the input control voltage on the actuator are demonstrated to present the effects of velocity feedback gain,pore distribution type,semi-vertex angle,impact loading,and rotational angular velocity on the traveling wave vibration control.
基金Project supported by the National Natural Science Foundation and of the Ministry of Construction of China
文摘For nonlinear stability problems of discretized conservative systems with multiple parameter variables and multiple state variables, the activation method is put forward, by which activated potential functions and activated equilibrium equations are derived. The activation method is the improvement and enhancement of Liapunov-Schmidt method in elastic stability theory. It is more generalized and more normalized than conventional perturbation methods. The activated potential functions may be transformed into normalized catastrophe potential functions. The activated equilibrium equations may be treated as bifurcation equations. The researches in this paper will motivate the combination of elastic stability theory with catastrophe theory and bifurcation theory
基金Supported by National Natural Science Foundation of China(No.11205076)
文摘In this study, the activation cross-sections were measured for ^(232)Th(n,2n)^(231)Th reactions at neutron energies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n)~4He reaction. Induced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. In the cross-section calculations, corrections were made regarding the effects of gamma-ray attenuation, dead-time, fluctuation of the neutron flux, and low energy neutrons. The measured cross-sections were compared with the literature data, evaluation data(ENDF-B/VII.1, JENDL-4.0 and CENDL-3.1), and the results of the model calculation(TALYS1.6).
基金the Deanship of Research and Graduate Studies at King Khalid University for funding this work through Large Research Project under grant number RGP2/111/46
文摘This study explores the complex dynamics of unsteady convective flow in micropolar nanofluids over a rough conical surface, with a focus on the effects of triple diffusive transport and Arrhenius activation energy. The primary objective is to understand the interplay among nonlinear convection, micro-rotation effects, and species diffusion under the influence of thermal and electromagnetic forces. The analysis is motivated by practical applications of cryogenic fluids, specifically liquid hydrogen and liquid nitrogen,where precise control of heat and mass transport is critical. The conical surface roughness is mathematically modeled as a high-frequency, small-amplitude sinusoidal waveform.To address the non-similar nature of the boundary-layer equations, Mangler's transformations are employed, followed by the implementation of a finite difference scheme for numerical solutions. The methodology further integrates a machine learning-based neural network to predict the skin friction under the influence of roughness-induced perturbations, ensuring computational efficiency and improved generalization. The study yields several novel findings. Notably, the presence of surface roughness introduces the wavelike modulations in the local skin friction coefficient. It is also observed that nonlinear convective interactions, enhanced by temperature gradients and vortex viscosity parameters, significantly intensify near-wall velocity gradients. Moreover, key physical quantities are correlated with governing parameters using power-law relationships, providing generalized predictive models. The validation of the numerical results is achieved through consistency checks with the existing limiting solutions and convergence analysis, ensuring the reliability of the proposed computational framework.
文摘In 2025,I had the honor of delivering keynote speeches at the conferences of the International Society for Diet and Activity Methods in Toronto,Canada,and the International Society of Behavioural Nutrition and Physical Activity in Auckland,Aotearoa,New Zealand.These opportunities prompted deep reflection on scientific research in general,and on physical activity and health research specifically.
基金support provided by the National Natural Science Foundation of China(No.22273043).
文摘As a novel class of purely organic fluores-cent materials,multiple resonance thermal-ly activated delayed fluorescence(MR-TADF)compounds hold significant promise for next-generation display technologies.The efficiency of exciton utilization and the overall performance of organic light-emit-ting devices are closely linked to the singlet-triplet energy gap(ΔE_(ST))of MR-TADF emitters.Identifying an economic and accu-rate theoretical approach to predictΔE_(ST)would be beneficial for high-throughput screening and facilitate the inverse design of MR-TADF molecules.In this study,we evaluated the S_(1)state energy(E(S_(1))),T_(1)state ener-gy(E(T_(1))),andΔE_(ST)using three different physical interpretations:adiabatic excitation ener-gy,vertical absorption energy,and vertical emission energy.We employed the time-depen-dent density functional theory(TDDFT)and delta self-consistent field(ΔSCF)methods to calculate E(S_(1)),E(T_(1)),andΔE_(ST)for 20 MR-TADF molecules reported in the literature.We compared these calculated values with experimental data obtained from fluorescence spec-troscopy at room-temperature(or 77 K)and phosphorescence spectroscopy conducted at 77 K.Our findings indicate that the vertical absorption energy at the S0 state minimum,deter-mined by theΔSCF method,accurately predicts the S_(1)state energy.Similarly,the vertical absorption energy at the S0 state minimum,calculated using the TDDFT method,effectively predicts the T_(1)state energy.TheΔE_(ST)derived from the difference between these two excita-tion energies exhibited the smallest mean absolute error of only 0.039 eV compared to the ex-perimental values.This combination represents the most accurate and cost-effective method reported to date for predicting theΔE_(ST)of MR-TADF molecules,and can be integrated into AI-driven inverse design workflows for new emitters.
文摘The component synthesis active vibration suppression method （CSVS） can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according to certain rules along the time axis. The synthesized command can suppress the arbitrary unwanted vibration harmonic while achieving the desired rigid body motion. The number of the components increases rapidly when the number of harmonic vibration is growing. In this article, the CSVS based on zero-placement technique is used to construct the synthesized command to suppress the multi-harmonics simultaneously in the discrete domain. The nature of zero-placement method is to put enough zeros to cancel system poles at necessary points. The designed synthesized command has equal time intervals between each component and which is much easier to be implemented. Using this method, the number of components increases linearly with the increasing of the number of being suppressed harmonics. For the spacecraft with flexible appendages, CSVS based on zero-placement is used to design the time optimal large angle maneuver control strategy. Simulations have verified the validity and superiority of the proposed approach.
基金Supported by National Science and Technology Support Program(2008BADA4B06,2011BAD16B12)International Plant Nutrition Institute (IPNI) Project~~
文摘[Objective] This paper aimed at exploring the effects of different nitrogen application methods on the enzyme activities of leaves at ear position in late growth stage of maize. [Method] By pot experiment, the superoxide dismutase （SOD） activity, peroxidase （POD） activity, malonyl dialdehyde （MDA） content and soluble protein content were determined. [Result] At the filling stage and ripening stage, with the increasing of nitrogen application rate, MDA content gradually decreased, while SOD activity, POD activity and soluble protein content increased. MDA content with two topdressing nitrogen was lower than that with one top dressing nitrogen at the same nitrogen application rate, while SOD activity, POD activity and soluble protein content with two topdressing nitrogen were higher than that with one topdressing nitrogen. [Conclusion] Different nitrogen application methods have relatively significant effects on the MDA content, SOD activity, POD activity and soluble protein content, which is of certain directive significance for preventing spring maize prematuration.
基金funded by the Special Funds for Industry System (CARS-03)Science and Technology Support Program (2012BAD04B07-03)
文摘The objective of this study was to evaluate the effects of wheat variety, food processing, and milling method on antioxidant properties. Black wheat variety Heibaoshi 1 had the highest total phenolic content(659.8 μg gallic acid equivalents g-1), total flavonoid content(319.3 μg rutin equivalents g-1), and antioxidant activity, whereas light purple wheat variety Shandongzimai 1 had the lowest total flavonoid content(236.2 μg rutin equivalents g-1) and antioxidant activity. Whole wheat flour and partially debranned grain flour had significantly higher total phenolic contents, total flavonoid contents, and antioxidant activity than refined flour(P < 0.05). Compared with flour, total phenolic contents, total flavonoid contents and antioxidant activity decreased in noodles and steamed bread, whereas noodles had slightly higher total phenolic and flavonoid content than steamed bread. Antioxidant activities(by ferric reducing ability of plasma assay) of steamed bread made from whole wheat flour, partially debranned grain flour, and refined flour were 23.5%, 21.1%, and 31.6% lower, respectively, than the corresponding values of flour. These results suggested that black whole wheat flour and partially debranned grain flour are beneficial to human health.
