Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up ...Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up table that contains the optical properties of five hydrometeor types—rain,cloud water,cloud ice,graupel,and snow—for the Advanced Radiative Transfer Modeling System(ARMS)at frequencies below 220 GHz.The discrete dipole approximation(DDA)method is employed to compute the single-scattering properties of solid cloud particles,modeling these particles as aggregated roughened bullet rosettes.The bulk optical properties of the cloud layer are derived by integrating the singlescattering properties with a modified Gamma size distribution,specifically for distributions with 18 effective radii.The bulk phase function is then projected onto a series of generalized spherical functions,applying the delta-M method for truncation.The results indicate that simulations using the newly developed nonspherical scattering look-up table exhibit significant consistency with observations under deep convection conditions.In contrast,assuming spherical solid cloud particles leads to excessive scattering at mid-frequency channels and insufficient scattering at high-frequency channels.This improvement in radiative transfer simulation accuracy for cloudy conditions will better support the assimilation of allsky microwave observations into numerical weather prediction models.·Frozen cloud particles were modeled as aggregates of bullet rosettes and the optical properties at microwave range were computed by DDA.·A complete process and technical details for constructing a look-up table of ARMS are provided.·The ARMS simulations generally show agreement with observations of MWTS and MWHS under typhoon conditions using the new look-up table.展开更多
Conventional model transfer techniques,requiring the labelled source data,are not applicable in the privacy-protected medical fields.For the challenging scenarios,recent source data-free domain adaptation(SFDA)has bec...Conventional model transfer techniques,requiring the labelled source data,are not applicable in the privacy-protected medical fields.For the challenging scenarios,recent source data-free domain adaptation(SFDA)has become a mainstream solution but losing focus on the inter-sample class information.This paper proposes a new Credible Local Context Representation approach for SFDA.Our main idea is to exploit the credible local context for more discriminative representation.Specifically,we enhance the source model's discrimination by information regulating.To capture the context,a discovery method is developed that performs fixed steps walking in deep space and takes the credible features in this path as the context.In the epoch-wise adaptation,deep clustering-like training is conducted with two major updates.First,the context for all target data is constructed and then the context-fused pseudo-labels providing semantic guidance are generated.Second,for each target data,a weighting fusion on its context forms the anchored neighbourhood structure;thus,the deep clustering is switched from individual-based to coarse-grained.Also,a new regularisation building is developed on the anchored neighbourhood to drive the deep coarse-grained learning.Experiments on three benchmarks indicate that the proposed method can achieve stateof-the-art results.展开更多
The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal ...The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal counterparts,one gains insights into the system's response under new mathematical frameworks.This paper presents a novel method for converting standard continuous differential equations into their fractal equivalents.This conversion occurs after the nonlinear system is transformed into its linear equivalent.Numerical analyses show that there are several resonance sites in the fractal system,which differ from the one resonance point found in the continuous system.One important finding is that the fractal system loses some of its stabilizing power when decaying behavior is transformed into a diffuse pattern.Interestingly,a decrease in the fractal order in resonance settings shows a stabilizing impact,highlighting the dynamics'complexity inside fractal systems.This endeavor to convert to fractals is a revolutionary technique that is being employed for the first time.展开更多
In order to solve for temperature fields in microwave heating for recycling asphalt mixtures, a two-dimensional heat transfer model for the asphalt mixtures within the heating range is built based on the theory of uns...In order to solve for temperature fields in microwave heating for recycling asphalt mixtures, a two-dimensional heat transfer model for the asphalt mixtures within the heating range is built based on the theory of unsteady heat conduction. Four onedimensional heat transfer models are established for the asphalt mixtures outside the heating range, which are simplified into four half-infinite solids. The intensity of the radiation electric field is calculated through experiment by using heating water loads. It is suggested that the mathematical model of boundary conditions can be established in two ways, which are theoretical deduction and experimental reverse. The actual temperature field is achieved by fitting temperatures of different positions collected in the heating experiment. The simulant temperature field, which is solved with the Matlab PDE toolbox, is in good agreement with the actual temperature field. The results indicate that the proposed models have high precision and can be directly used to calculate the temperature distribution of asphalt pavements.展开更多
Two mono iron complexes Fe（CO）2PR3（NN） （R = Cy （3）, Ph （4）, NN = o-phenylenediamine dianion ligand, N2H2Ph2-） derived from the ligand substitution of Fe（CO）3hPR3 by the NN ligand were isolated and structur...Two mono iron complexes Fe（CO）2PR3（NN） （R = Cy （3）, Ph （4）, NN = o-phenylenediamine dianion ligand, N2H2Ph2-） derived from the ligand substitution of Fe（CO）3hPR3 by the NN ligand were isolated and structurally characterized by single crystal X-ray diffraction. They have a similar first coordination sphere and oxidation state of the iron center as the [Fe]-hydrogenase active site, and can be a model of it IR demonstrated that the effect of the NN ligand on the coordinated CO stretch- ing frequencies was due to its excellent electron donating ability. The reversible protonation/deprotonation of the NN ligand was identified by infrared spectroscopy and density functional theory computation. The NN ligand is an effective proton acceptor as the internal base of the cysteine thiolate ligand in [Fe]-hydrogenase. The electrochemical properties of complexes 3, 4 were investigated by cyclic voltammograms. Complex 3 catalyzed the transfer hydrogenation of benzoquinone to hydroquinone effectively under mild conditions.展开更多
AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial cultur...AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial culture medium as control (deMan Rogosa Sharpe) in drinking water for one week prior to transfer of a mix of naive and regulatory T cells until sacrifice. RESULTS: All recipient mice developed signs of colonic inflammation, but a significant reduction of weight loss was observed in B. lactis-fed recipient mice compared to control mice. Moreover, a trend toward a diminution of mucosal thickness and attenuated epithelial damage was revealed. Colonic expression of pro-inflammatory and T cell markers was significantly reduced in B. lactis-fed recipient mice compared to controls. Concomitantly, forkhead box protein 3, a marker of regulatory T cells, was significantly up-regulated by B. lactis. CONCLUSION: Daily oral administration of B. lactis was able to reduce inflammatory and T cells mediators and to promote regulatory T cells specific markers in a mouse model of colitis.展开更多
Hydrothermal processes are key components in permafrost dynamics; these processes are integral to global wanning. In this study the coupled heat and mass transfer model for （CoupModel） the soil-plant-atmosphere-syst...Hydrothermal processes are key components in permafrost dynamics; these processes are integral to global wanning. In this study the coupled heat and mass transfer model for （CoupModel） the soil-plant-atmosphere-system is applied in high-altitude permafrost regions and to model hydrothermal transfer processes in freeze-thaw cycles. Measured meteorological forcing and soil and vegetation properties are used in the CoupModel for the period from January 1, 2009 to December 31, 2012 at the Tanggula observation site in the Qinghai-Tibet Plateau. A 24-h time step is used in the model simulation. The results show that the simulated soil temperature and water content, as well as the frozen depth compare well with the measured data. The coefficient of determination （R2） is 0.97 for the mean soil temperature and 0.73 for the mean soil water content, respectively. The simulated soil heat flux at a depth of 0-20 cm is also consistent with the monitored data. An analysis is performed on the simulated hydrothermal transfer processes from the deep soil layer to the upper one during the freezing and thawing period. At the beginning of the freezing period, the water in the deep soil layer moves upward to the freezing front and releases heat during the freezing process. When the soil layer is completely frozen, there are no vertical water ex- changes between the soil layers, and the heat exchange process is controlled by the vertical soil temperature gradient. During the thaw- ing period, the downward heat process becomes more active due to increased incoming shortwave radiation at the ground surface. The melt water is quickly dissolved in the soil, and the soil water movement only changes in the shallow soil layer. Subsequently, the model was used to provide an evaluation of the potential response of the active layer to different scenarios of initial water content and climate warming at the Tanggula site. The results reveal that the soil water content and the organic layer provide protection against active layer deepening in summer, so climate warming will cause the permafrost active layer to become deeoer and permafrost degradation.展开更多
In this paper, a generalized layered model for radiation transfer in canopy with high vertical resolution is developed. Differing from the two-stream approximate radiation transfer model commonly used in the land surf...In this paper, a generalized layered model for radiation transfer in canopy with high vertical resolution is developed. Differing from the two-stream approximate radiation transfer model commonly used in the land surface models, the generalized model takes into account the effect of complicated canopy morphology and inhomogeneous optical properties of leaves on radiation transfer within the canopy. In the model, the total leaf area index （LAI） of the canopy is divided into many layers. At a given layer, the influences of diffuse radiation angle distributions and leaf angle distributions on radiation transfer within the canopy are considered. The derivation of equations serving the model are described in detail, and these can deal with various diffuse radiation transfers in quite broad categories of canopy with quite inhomogeneons vertical structures and uneven leaves with substantially different optical properties of adaxial and abaxial faces of the leaves. The model is used to simulate the radiation transfer for canopies with horizontal leaves to validate the generalized model. Results from the model are compared with those from the two-stream scheme, and differences between these two models are discussed.展开更多
Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality.However,a significant technical challenge in grinding is the potential increas...Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality.However,a significant technical challenge in grinding is the potential increase in temperature due to high specific energy,which can lead to surface thermal damage.Therefore,ensuring control over the surface integrity of workpieces during grinding becomes a critical concern.This necessitates the development of temperature field models that consider various parameters,such as workpiece materials,grinding wheels,grinding parameters,cooling methods,and media,to guide industrial production.This study thoroughly analyzes and summarizes grinding temperature field models.First,the theory of the grinding temperature field is investigated,classifying it into traditional models based on a continuous belt heat source and those based on a discrete heat source,depending on whether the heat source is uniform and continuous.Through this examination,a more accurate grinding temperature model that closely aligns with practical grinding conditions is derived.Subsequently,various grinding thermal models are summarized,including models for the heat source distribution,energy distribution proportional coefficient,and convective heat transfer coefficient.Through comprehensive research,the most widely recognized,utilized,and accurate model for each category is identified.The application of these grinding thermal models is reviewed,shedding light on the governing laws that dictate the influence of the heat source distribution,heat distribution,and convective heat transfer in the grinding arc zone on the grinding temperature field.Finally,considering the current issues in the field of grinding temperature,potential future research directions are proposed.The aim of this study is to provide theoretical guidance and technical support for predicting workpiece temperature and improving surface integrity.展开更多
The interstand tension control is one of the most important ways to meet tight tolerances for strip product quality during tandem cold rolling process. Using coordinate analysis and parabolic approximation for the mas...The interstand tension control is one of the most important ways to meet tight tolerances for strip product quality during tandem cold rolling process. Using coordinate analysis and parabolic approximation for the mass flow balance principle, the strip velocities eliminating the use of forward slips and backward slips were calculated. In order to reduce the effect of roll eccentricity on the tension measurement, a filter based on bilinear transformation was de- signed. Applying a first-order Taylor series approximation, the transfer function matrix model of interstand tension stress was derived. The actual measurements on-site and the final calculation results showed that the established model had high calculation accuracy and was beneficial for interstand tension control of random cold rolling process.展开更多
The load transfer analytical method is applied to study the bearing mechanism of piles with vertical load in this paper. According to the different hardening rules of soil or rock around the pile shaft, such as work-s...The load transfer analytical method is applied to study the bearing mechanism of piles with vertical load in this paper. According to the different hardening rules of soil or rock around the pile shaft, such as work-softening, ideal elasto-plastic and work-hardening, a universal tri-linear load transfer model is suggested for the development of side and tip resistance by various types of soil (rock) with the consideration of sediment at the bottom of the pile. Based on the model, a formula is derived for the relationship between the settlement and load on the pile top to determine the vertical bearing capacity, taking into account such factors as the characteristics of the stratum, the side resistance along the shaft, and tip resistance under the pile tip. A close agreement of the calculated results with the measured data from a field test pile lends confidence to the future application of the present approach in engineering practice.展开更多
Gear fault diagnosis technologies have received rapid development and been effectively implemented in many engineering applications.However,the various working conditions would degrade the diagnostic performance and m...Gear fault diagnosis technologies have received rapid development and been effectively implemented in many engineering applications.However,the various working conditions would degrade the diagnostic performance and make gear fault diagnosis(GFD)more and more challenging.In this paper,a novel model parameter transfer(NMPT)is proposed to boost the performance of GFD under varying working conditions.Based on the previous transfer strategy that controls empirical risk of source domain,this method further integrates the superiorities of multi-task learning with the idea of transfer learning(TL)to acquire transferable knowledge by minimizing the discrepancies of separating hyperplanes between one specific working condition(target domain)and another(source domain),and then transferring both commonality and specialty parameters over tasks to make use of source domain samples to assist target GFD task when sufficient labeled samples from target domain are unavailable.For NMPT implementation,insufficient target domain features and abundant source domain features with supervised information are fed into NMPT model to train a robust classifier for target GFD task.Related experiments prove that NMPT is expected to be a valuable technology to boost practical GFD performance under various working conditions.The proposed methods provides a transfer learning-based framework to handle the problem of insufficient training samples in target task caused by variable operation conditions.展开更多
This research investigates a numerical simulation of swirling turbulent non-premixed combustion.The effects on the combustion characteristics are examined with three turbulence models:namely as the Reynolds stress mod...This research investigates a numerical simulation of swirling turbulent non-premixed combustion.The effects on the combustion characteristics are examined with three turbulence models:namely as the Reynolds stress model,spectral turbulence analysis and Re-Normalization Group.In addition,the P-1 and discrete ordinate(DO)models are used to simulate the radiative heat transfer in this model.The governing equations associated with the required boundary conditions are solved using the numerical model.The accuracy of this model is validated with the published experimental data and the comparison elucidates that there is a reasonable agreement between the obtained values from this model and the corresponding experimental quantities.Among different models proposed in this research,the Reynolds stress model with the Probability Density Function(PDF)approach is more accurate(nearly up to 50%)than other turbulent models for a swirling flow field.Regarding the effect of radiative heat transfer model,it is observed that the discrete ordinate model is more precise than the P-1 model in anticipating the experimental behavior.This model is able to simulate the subcritical nature of the isothermal flow as well as the size and shape of the internal recirculation induced by the swirl due to combustion.展开更多
A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain p...A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain parameters and disturbance, we propose a robust adaptive controller based on backstepping algorithm of Lyaponov function. Numerical simulations indicate the validity of the proposed controller.展开更多
Purpose:To evaluate the efficacy of the Seamless Transfer of Care Model(STCM)to improve readmission occurrence of patients withstroke.Methods:The sample was comprised of fifty-nine subjects with stroke who were hospit...Purpose:To evaluate the efficacy of the Seamless Transfer of Care Model(STCM)to improve readmission occurrence of patients withstroke.Methods:The sample was comprised of fifty-nine subjects with stroke who were hospitalized in the geriatric and neurology departments of a large university hospital in China.Subjects were allocated to an STCM group(n=30)or a routine care(control)group(n=29).Results:Compared with the control group,the STCM group had a higher quality of life(p<0.05),higher compliance(p<0.05)and a lower readmission rate(p<0.05).Conclusion:Based on our results,the application of the STCM in Chinese stroke patients can improve quality of life and compliance,and reduce readmission rate.展开更多
Forward radiative transfer(RT)models are essential for atmospheric applications such as remote sensing and weather and climate models,where computational efficiency becomes equally as important as accuracy for high-re...Forward radiative transfer(RT)models are essential for atmospheric applications such as remote sensing and weather and climate models,where computational efficiency becomes equally as important as accuracy for high-resolution hyperspectral measurements that need rigorous RT simulations for thousands of channels.This study introduces a fast and accurate RT model for the hyperspectral infrared(HIR)sounder based on principal component analysis(PCA)or machine learning(i.e.,neural network,NN).The Geosynchronous Interferometric Infrared Sounder(GIIRS),the first HIR sounder onboard the geostationary Fengyun-4 satellites,is considered to be a candidate example for model development and validation.Our method uses either PCA or NN(PCA/NN)twice for the atmospheric transmittance and radiance,respectively,to reduce the number of independent but similar simulations to accelerate RT simulations;thereby,it is referred to as a multi-domain compression model.The first PCA/NN gives monochromatic gas transmittance in both spectral and atmospheric pressure domains for each gas independently.The second PCA/NN is performed in the traditional spectral radiance domain.Meanwhile,a new method is introduced to choose representative variables for the PCA/NN scheme developments.The model is three orders of magnitude faster than the standard line-by-line-based simulations with averaged brightness temperature difference(BTD)less than 0.1 K,and the compressions based on PCA or NN methods result in comparable efficiency and accuracy.Our fast model not only avoids an excessively complicated transmittance scheme by using PCA/NN but is also highly flexible for hyperspectral instruments with similar spectral ranges simply by updating the corresponding spectral response functions.展开更多
The high degree of reversibility of heat integrated distillation column(HIDiC) has been thermodynamically interpreted by the entropy method. In this paper, a heat transfer model and a more universal method were propos...The high degree of reversibility of heat integrated distillation column(HIDiC) has been thermodynamically interpreted by the entropy method. In this paper, a heat transfer model and a more universal method were proposed, through which the overall heat transfer coefficient at different height of column under different operating conditions could be obtained before the experiment. Then the separation of a binary ethanol-water system was carried out experimentally as a case study to verify the heat transfer model and the aforementioned calculation method. The close results between the calculation, the simulation, and the experiments suggested that the proposed model and the calculation method in this paper were accurate and applicable. Meanwhile, it was demonstrated that the HIDiC shows obvious effect of reducing entropy increase and improving thermodynamic efficiency as compared to conventional distillation column.展开更多
This paper compares the predictions by two radiative transfer models-the two-stream approximation model and the generalized layered model （developed by the authors） in land surface processes -for different canopies ...This paper compares the predictions by two radiative transfer models-the two-stream approximation model and the generalized layered model （developed by the authors） in land surface processes -for different canopies under direct or diffuse radiation conditions. The comparison indicates that there are significant differences between the two models, especially in the near infrared （NIR） band. Results of canopy reflectance from the two-stream model are larger than those from the generalized model. However, results of canopy absorptance from the two-stream model are larger in some cases and smaller in others compared to those from the generalized model, depending on the cases involved. In the visible （VIS） band, canopy reflectance is smaller and canopy absorptance larger from the two-stream model compared to the generalized model when the Leaf Area Index （LAI） is low and soil reflectance is high. In cases of canopies with vertical leaf angles, the differences of reflectance and absorptance in the VIS and NIR bands between the two models are especially large. Two commonly occurring cases, with which the two-stream model cannot deal accurately, are also investigated. One is for a canopy with different adaxial and abaxial leaf optical properties; and the other is for incident sky diffuse radiation with a non-uniform distribution. Comparison of the generalized model within the same canopy for both uniform and non-uniform incident diffuse radiation inputs shows smaller differences in general. However, there is a measurable difference between these radiation inputs for a canopy with high leaf angle. This indicates that the application of the two-stream model to a canopy with different adaxial and abaxial leaf optical properties will introduce non-negligible errors.展开更多
In this paper, firstly, a simplified version （SGRTM） of the generalized layered radiative transfer model （GRTM） within the canopy, developed by us, is presented. It reduces the information requirement of inputted ...In this paper, firstly, a simplified version （SGRTM） of the generalized layered radiative transfer model （GRTM） within the canopy, developed by us, is presented. It reduces the information requirement of inputted sky diffuse radiation, as well as of canopy morphology, and in turn saves computer resources. Results from the SGRTM agree perfectly with those of the GRTM. Secondly, by applying the linear superposition principle of the optics and by using the basic solutions of the GRTM for radiative transfer within the canopy under the condition of assumed zero soil reflectance, two sets of explicit analytical solutions of radiative transfer within the canopy with any soil reflectance magnitude are derived： one for incident diffuse, and the other for direct beam radiation. The explicit analytical solutions need two sets of basic solutions of canopy reflectance and transmittance under zero soil reflectance, run by the model for both diffuse and direct beam radiation. One set of basic solutions is the canopy reflectance αf （written as α1 for direct beam radiation） and transmittance βf （written as β1 for direction beam radiation） with zero soil reflectance for the downward radiation from above the canopy （i.e. sky）, and the other set is the canopy reflectance （αb） and transmittance βb for the upward radiation from below the canopy （i.e., ground）. Under the condition of the same plant architecture in the vertical layers, and the same leaf adaxial and abaxial optical properties in the canopies for the uniform diffuse radiation, the explicit solutions need only one set of basic solutions, because under this condition the two basic solutions are equal, i.e., αf = αb and βf = βb. Using the explicit analytical solutions, the fractions of any kind of incident solar radiation reflected from （defined as surface albedo, or canopy reflectance）, transmitted through （defined as canopy transmittance）, and absorbed by （defined as canopy absorptance） the canopy and other properties pertinent to the radiative transfer within the canopy can be estimated easily on the ground surface below the canopy （soil or snow surface） with any reflectance magnitudes. The simplified transfer model is proven to have a similar accuracy compared to the detailed model, as well as very efficient computing.展开更多
Thin-film composite(TFC)reverse osmosis(RO)membranes have attracted considerable attention in water treatment and desalination processes due to their specific separation advantages.Nevertheless,the trade-off effect be...Thin-film composite(TFC)reverse osmosis(RO)membranes have attracted considerable attention in water treatment and desalination processes due to their specific separation advantages.Nevertheless,the trade-off effect between water flux and salt rejection poses huge challenges to further improvement in TFC RO membrane performance.Numerous research works have been dedicated to optimizing membrane fabrication and modification for addressing this issue.In the meantime,several reviews summarized these approaches.However,the existing reviews seldom analyzed these methods from a theoretical perspective and thus failed to offer effective optimization directions for the RO process from the root cause.In this review,we first propose a mass transfer model to facilitate a better understanding of the entire process of how water and solute permeate through RO membranes in detail,namely the migration process outside the membrane,the dissolution process on the membrane surface,and the diffusion process within the membrane.Thereafter,the water and salt mass transfer behaviors obtained from model deduction are comprehensively analyzed to provide potential guidelines for alleviating the trade-off effect between water flux and salt rejection in the RO process.Finally,inspired by the theoretical analysis and the accurate identification of existing bottlenecks,several promising strategies for both regulating RO membranes and optimizing operational conditions are proposed to further exploit the potential of RO membrane performance.This review is expected to guide the development of high-performance RO membranes from a mass transfer theory standpoint.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3900400)the National Natural Science Foundation of China(Grant Nos.U2142212 and 42361074)。
文摘Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up table that contains the optical properties of five hydrometeor types—rain,cloud water,cloud ice,graupel,and snow—for the Advanced Radiative Transfer Modeling System(ARMS)at frequencies below 220 GHz.The discrete dipole approximation(DDA)method is employed to compute the single-scattering properties of solid cloud particles,modeling these particles as aggregated roughened bullet rosettes.The bulk optical properties of the cloud layer are derived by integrating the singlescattering properties with a modified Gamma size distribution,specifically for distributions with 18 effective radii.The bulk phase function is then projected onto a series of generalized spherical functions,applying the delta-M method for truncation.The results indicate that simulations using the newly developed nonspherical scattering look-up table exhibit significant consistency with observations under deep convection conditions.In contrast,assuming spherical solid cloud particles leads to excessive scattering at mid-frequency channels and insufficient scattering at high-frequency channels.This improvement in radiative transfer simulation accuracy for cloudy conditions will better support the assimilation of allsky microwave observations into numerical weather prediction models.·Frozen cloud particles were modeled as aggregates of bullet rosettes and the optical properties at microwave range were computed by DDA.·A complete process and technical details for constructing a look-up table of ARMS are provided.·The ARMS simulations generally show agreement with observations of MWTS and MWHS under typhoon conditions using the new look-up table.
基金National Key R&D Program of China,Grant/Award Numbers:2018YFE0203900,2020YFB1313600German Research Foundation,Hamburg Landesforschungsförderungsprojekt Cross,Grant/Award Number:Sonderforschungsbereich Transregio 169+2 种基金Shanghai Artificial Intelligence Innovation Development Special Support Project,Grant/Award Number:3920365001Horizon2020 RISE project STEP2DYNA,Grant/Award Number:691154National Natural Science Foundation of China,Grant/Award Numbers:61773083,62206168,62276048,U1813202。
文摘Conventional model transfer techniques,requiring the labelled source data,are not applicable in the privacy-protected medical fields.For the challenging scenarios,recent source data-free domain adaptation(SFDA)has become a mainstream solution but losing focus on the inter-sample class information.This paper proposes a new Credible Local Context Representation approach for SFDA.Our main idea is to exploit the credible local context for more discriminative representation.Specifically,we enhance the source model's discrimination by information regulating.To capture the context,a discovery method is developed that performs fixed steps walking in deep space and takes the credible features in this path as the context.In the epoch-wise adaptation,deep clustering-like training is conducted with two major updates.First,the context for all target data is constructed and then the context-fused pseudo-labels providing semantic guidance are generated.Second,for each target data,a weighting fusion on its context forms the anchored neighbourhood structure;thus,the deep clustering is switched from individual-based to coarse-grained.Also,a new regularisation building is developed on the anchored neighbourhood to drive the deep coarse-grained learning.Experiments on three benchmarks indicate that the proposed method can achieve stateof-the-art results.
文摘The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal counterparts,one gains insights into the system's response under new mathematical frameworks.This paper presents a novel method for converting standard continuous differential equations into their fractal equivalents.This conversion occurs after the nonlinear system is transformed into its linear equivalent.Numerical analyses show that there are several resonance sites in the fractal system,which differ from the one resonance point found in the continuous system.One important finding is that the fractal system loses some of its stabilizing power when decaying behavior is transformed into a diffuse pattern.Interestingly,a decrease in the fractal order in resonance settings shows a stabilizing impact,highlighting the dynamics'complexity inside fractal systems.This endeavor to convert to fractals is a revolutionary technique that is being employed for the first time.
基金The Key Project of Science and Technology of Ministryof Education (No.105085)the Specialized Research Fund of Science andTechnology Production Translation of Jiangsu Province (No.BA2006068).
文摘In order to solve for temperature fields in microwave heating for recycling asphalt mixtures, a two-dimensional heat transfer model for the asphalt mixtures within the heating range is built based on the theory of unsteady heat conduction. Four onedimensional heat transfer models are established for the asphalt mixtures outside the heating range, which are simplified into four half-infinite solids. The intensity of the radiation electric field is calculated through experiment by using heating water loads. It is suggested that the mathematical model of boundary conditions can be established in two ways, which are theoretical deduction and experimental reverse. The actual temperature field is achieved by fitting temperatures of different positions collected in the heating experiment. The simulant temperature field, which is solved with the Matlab PDE toolbox, is in good agreement with the actual temperature field. The results indicate that the proposed models have high precision and can be directly used to calculate the temperature distribution of asphalt pavements.
基金supported by the National Natural Science Foundation of China(21103121,21276187)Tianjin Municipal Natural Science Foundation(13JCQNJC05800)the Specialized Research Fund for the Doctoral Program of Higher Education(20121317110009)~~
文摘Two mono iron complexes Fe（CO）2PR3（NN） （R = Cy （3）, Ph （4）, NN = o-phenylenediamine dianion ligand, N2H2Ph2-） derived from the ligand substitution of Fe（CO）3hPR3 by the NN ligand were isolated and structurally characterized by single crystal X-ray diffraction. They have a similar first coordination sphere and oxidation state of the iron center as the [Fe]-hydrogenase active site, and can be a model of it IR demonstrated that the effect of the NN ligand on the coordinated CO stretch- ing frequencies was due to its excellent electron donating ability. The reversible protonation/deprotonation of the NN ligand was identified by infrared spectroscopy and density functional theory computation. The NN ligand is an effective proton acceptor as the internal base of the cysteine thiolate ligand in [Fe]-hydrogenase. The electrochemical properties of complexes 3, 4 were investigated by cyclic voltammograms. Complex 3 catalyzed the transfer hydrogenation of benzoquinone to hydroquinone effectively under mild conditions.
文摘AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial culture medium as control (deMan Rogosa Sharpe) in drinking water for one week prior to transfer of a mix of naive and regulatory T cells until sacrifice. RESULTS: All recipient mice developed signs of colonic inflammation, but a significant reduction of weight loss was observed in B. lactis-fed recipient mice compared to control mice. Moreover, a trend toward a diminution of mucosal thickness and attenuated epithelial damage was revealed. Colonic expression of pro-inflammatory and T cell markers was significantly reduced in B. lactis-fed recipient mice compared to controls. Concomitantly, forkhead box protein 3, a marker of regulatory T cells, was significantly up-regulated by B. lactis. CONCLUSION: Daily oral administration of B. lactis was able to reduce inflammatory and T cells mediators and to promote regulatory T cells specific markers in a mouse model of colitis.
基金National Major Scientific Project of China(No.2013CBA01803)Science Fund for Creative Research Groups of National Natural Science Foundation of China(No.41121001)+1 种基金National Natural Science Foundation of China(No.41271081)Foundation of One Hundred Person Project of Chinese Academy of Sciences(No.51Y251571)
文摘Hydrothermal processes are key components in permafrost dynamics; these processes are integral to global wanning. In this study the coupled heat and mass transfer model for （CoupModel） the soil-plant-atmosphere-system is applied in high-altitude permafrost regions and to model hydrothermal transfer processes in freeze-thaw cycles. Measured meteorological forcing and soil and vegetation properties are used in the CoupModel for the period from January 1, 2009 to December 31, 2012 at the Tanggula observation site in the Qinghai-Tibet Plateau. A 24-h time step is used in the model simulation. The results show that the simulated soil temperature and water content, as well as the frozen depth compare well with the measured data. The coefficient of determination （R2） is 0.97 for the mean soil temperature and 0.73 for the mean soil water content, respectively. The simulated soil heat flux at a depth of 0-20 cm is also consistent with the monitored data. An analysis is performed on the simulated hydrothermal transfer processes from the deep soil layer to the upper one during the freezing and thawing period. At the beginning of the freezing period, the water in the deep soil layer moves upward to the freezing front and releases heat during the freezing process. When the soil layer is completely frozen, there are no vertical water ex- changes between the soil layers, and the heat exchange process is controlled by the vertical soil temperature gradient. During the thaw- ing period, the downward heat process becomes more active due to increased incoming shortwave radiation at the ground surface. The melt water is quickly dissolved in the soil, and the soil water movement only changes in the shallow soil layer. Subsequently, the model was used to provide an evaluation of the potential response of the active layer to different scenarios of initial water content and climate warming at the Tanggula site. The results reveal that the soil water content and the organic layer provide protection against active layer deepening in summer, so climate warming will cause the permafrost active layer to become deeoer and permafrost degradation.
文摘In this paper, a generalized layered model for radiation transfer in canopy with high vertical resolution is developed. Differing from the two-stream approximate radiation transfer model commonly used in the land surface models, the generalized model takes into account the effect of complicated canopy morphology and inhomogeneous optical properties of leaves on radiation transfer within the canopy. In the model, the total leaf area index （LAI） of the canopy is divided into many layers. At a given layer, the influences of diffuse radiation angle distributions and leaf angle distributions on radiation transfer within the canopy are considered. The derivation of equations serving the model are described in detail, and these can deal with various diffuse radiation transfers in quite broad categories of canopy with quite inhomogeneons vertical structures and uneven leaves with substantially different optical properties of adaxial and abaxial faces of the leaves. The model is used to simulate the radiation transfer for canopies with horizontal leaves to validate the generalized model. Results from the model are compared with those from the two-stream scheme, and differences between these two models are discussed.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52205481,51975305 and 52105457)Shandong Natural Science Foundation(Grant Nos.ZR2020ME158,ZR2023QE057,ZR2022QE028,ZR2021QE116,ZR2020KE027,and ZR2022QE159)+1 种基金Qingdao Science and Technology Planning Park Cultivation Plan(23-1-5-yqpy-17-qy)China Postdoctral Science Foundation(2021M701810).
文摘Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality.However,a significant technical challenge in grinding is the potential increase in temperature due to high specific energy,which can lead to surface thermal damage.Therefore,ensuring control over the surface integrity of workpieces during grinding becomes a critical concern.This necessitates the development of temperature field models that consider various parameters,such as workpiece materials,grinding wheels,grinding parameters,cooling methods,and media,to guide industrial production.This study thoroughly analyzes and summarizes grinding temperature field models.First,the theory of the grinding temperature field is investigated,classifying it into traditional models based on a continuous belt heat source and those based on a discrete heat source,depending on whether the heat source is uniform and continuous.Through this examination,a more accurate grinding temperature model that closely aligns with practical grinding conditions is derived.Subsequently,various grinding thermal models are summarized,including models for the heat source distribution,energy distribution proportional coefficient,and convective heat transfer coefficient.Through comprehensive research,the most widely recognized,utilized,and accurate model for each category is identified.The application of these grinding thermal models is reviewed,shedding light on the governing laws that dictate the influence of the heat source distribution,heat distribution,and convective heat transfer in the grinding arc zone on the grinding temperature field.Finally,considering the current issues in the field of grinding temperature,potential future research directions are proposed.The aim of this study is to provide theoretical guidance and technical support for predicting workpiece temperature and improving surface integrity.
基金Item Sponsored by Fundamental Research Funds for the Central Universities of China(N110307001)
文摘The interstand tension control is one of the most important ways to meet tight tolerances for strip product quality during tandem cold rolling process. Using coordinate analysis and parabolic approximation for the mass flow balance principle, the strip velocities eliminating the use of forward slips and backward slips were calculated. In order to reduce the effect of roll eccentricity on the tension measurement, a filter based on bilinear transformation was de- signed. Applying a first-order Taylor series approximation, the transfer function matrix model of interstand tension stress was derived. The actual measurements on-site and the final calculation results showed that the established model had high calculation accuracy and was beneficial for interstand tension control of random cold rolling process.
文摘The load transfer analytical method is applied to study the bearing mechanism of piles with vertical load in this paper. According to the different hardening rules of soil or rock around the pile shaft, such as work-softening, ideal elasto-plastic and work-hardening, a universal tri-linear load transfer model is suggested for the development of side and tip resistance by various types of soil (rock) with the consideration of sediment at the bottom of the pile. Based on the model, a formula is derived for the relationship between the settlement and load on the pile top to determine the vertical bearing capacity, taking into account such factors as the characteristics of the stratum, the side resistance along the shaft, and tip resistance under the pile tip. A close agreement of the calculated results with the measured data from a field test pile lends confidence to the future application of the present approach in engineering practice.
基金Supported by National Natural Science Foundation of China(Grant No.51835009).
文摘Gear fault diagnosis technologies have received rapid development and been effectively implemented in many engineering applications.However,the various working conditions would degrade the diagnostic performance and make gear fault diagnosis(GFD)more and more challenging.In this paper,a novel model parameter transfer(NMPT)is proposed to boost the performance of GFD under varying working conditions.Based on the previous transfer strategy that controls empirical risk of source domain,this method further integrates the superiorities of multi-task learning with the idea of transfer learning(TL)to acquire transferable knowledge by minimizing the discrepancies of separating hyperplanes between one specific working condition(target domain)and another(source domain),and then transferring both commonality and specialty parameters over tasks to make use of source domain samples to assist target GFD task when sufficient labeled samples from target domain are unavailable.For NMPT implementation,insufficient target domain features and abundant source domain features with supervised information are fed into NMPT model to train a robust classifier for target GFD task.Related experiments prove that NMPT is expected to be a valuable technology to boost practical GFD performance under various working conditions.The proposed methods provides a transfer learning-based framework to handle the problem of insufficient training samples in target task caused by variable operation conditions.
基金the provided funding resources by Mohsen Saffari Pour from the National Elites Foundation of IranStiftelsen Axel Hultgerns of Sweden for supporting this research。
文摘This research investigates a numerical simulation of swirling turbulent non-premixed combustion.The effects on the combustion characteristics are examined with three turbulence models:namely as the Reynolds stress model,spectral turbulence analysis and Re-Normalization Group.In addition,the P-1 and discrete ordinate(DO)models are used to simulate the radiative heat transfer in this model.The governing equations associated with the required boundary conditions are solved using the numerical model.The accuracy of this model is validated with the published experimental data and the comparison elucidates that there is a reasonable agreement between the obtained values from this model and the corresponding experimental quantities.Among different models proposed in this research,the Reynolds stress model with the Probability Density Function(PDF)approach is more accurate(nearly up to 50%)than other turbulent models for a swirling flow field.Regarding the effect of radiative heat transfer model,it is observed that the discrete ordinate model is more precise than the P-1 model in anticipating the experimental behavior.This model is able to simulate the subcritical nature of the isothermal flow as well as the size and shape of the internal recirculation induced by the swirl due to combustion.
文摘A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain parameters and disturbance, we propose a robust adaptive controller based on backstepping algorithm of Lyaponov function. Numerical simulations indicate the validity of the proposed controller.
基金This study was supported by the Research Foundation of Fudan University(FNF201208)Health And Family Planning Commission Of Shanghai(201440090)and Minhang(2012MHZ028).
文摘Purpose:To evaluate the efficacy of the Seamless Transfer of Care Model(STCM)to improve readmission occurrence of patients withstroke.Methods:The sample was comprised of fifty-nine subjects with stroke who were hospitalized in the geriatric and neurology departments of a large university hospital in China.Subjects were allocated to an STCM group(n=30)or a routine care(control)group(n=29).Results:Compared with the control group,the STCM group had a higher quality of life(p<0.05),higher compliance(p<0.05)and a lower readmission rate(p<0.05).Conclusion:Based on our results,the application of the STCM in Chinese stroke patients can improve quality of life and compliance,and reduce readmission rate.
基金supported by the National Natural Science Foundation of China(Grant No.42122038)。
文摘Forward radiative transfer(RT)models are essential for atmospheric applications such as remote sensing and weather and climate models,where computational efficiency becomes equally as important as accuracy for high-resolution hyperspectral measurements that need rigorous RT simulations for thousands of channels.This study introduces a fast and accurate RT model for the hyperspectral infrared(HIR)sounder based on principal component analysis(PCA)or machine learning(i.e.,neural network,NN).The Geosynchronous Interferometric Infrared Sounder(GIIRS),the first HIR sounder onboard the geostationary Fengyun-4 satellites,is considered to be a candidate example for model development and validation.Our method uses either PCA or NN(PCA/NN)twice for the atmospheric transmittance and radiance,respectively,to reduce the number of independent but similar simulations to accelerate RT simulations;thereby,it is referred to as a multi-domain compression model.The first PCA/NN gives monochromatic gas transmittance in both spectral and atmospheric pressure domains for each gas independently.The second PCA/NN is performed in the traditional spectral radiance domain.Meanwhile,a new method is introduced to choose representative variables for the PCA/NN scheme developments.The model is three orders of magnitude faster than the standard line-by-line-based simulations with averaged brightness temperature difference(BTD)less than 0.1 K,and the compressions based on PCA or NN methods result in comparable efficiency and accuracy.Our fast model not only avoids an excessively complicated transmittance scheme by using PCA/NN but is also highly flexible for hyperspectral instruments with similar spectral ranges simply by updating the corresponding spectral response functions.
基金supported by the National Key Research and Development Program of China(2017YFB0602500)the Foundation for High Level Talents of Hebei (A2017002032).
文摘The high degree of reversibility of heat integrated distillation column(HIDiC) has been thermodynamically interpreted by the entropy method. In this paper, a heat transfer model and a more universal method were proposed, through which the overall heat transfer coefficient at different height of column under different operating conditions could be obtained before the experiment. Then the separation of a binary ethanol-water system was carried out experimentally as a case study to verify the heat transfer model and the aforementioned calculation method. The close results between the calculation, the simulation, and the experiments suggested that the proposed model and the calculation method in this paper were accurate and applicable. Meanwhile, it was demonstrated that the HIDiC shows obvious effect of reducing entropy increase and improving thermodynamic efficiency as compared to conventional distillation column.
基金supported by the National Natural Science Foundation of China under Grant Nos.40233034,40605024,40575043,and 40305011.
文摘This paper compares the predictions by two radiative transfer models-the two-stream approximation model and the generalized layered model （developed by the authors） in land surface processes -for different canopies under direct or diffuse radiation conditions. The comparison indicates that there are significant differences between the two models, especially in the near infrared （NIR） band. Results of canopy reflectance from the two-stream model are larger than those from the generalized model. However, results of canopy absorptance from the two-stream model are larger in some cases and smaller in others compared to those from the generalized model, depending on the cases involved. In the visible （VIS） band, canopy reflectance is smaller and canopy absorptance larger from the two-stream model compared to the generalized model when the Leaf Area Index （LAI） is low and soil reflectance is high. In cases of canopies with vertical leaf angles, the differences of reflectance and absorptance in the VIS and NIR bands between the two models are especially large. Two commonly occurring cases, with which the two-stream model cannot deal accurately, are also investigated. One is for a canopy with different adaxial and abaxial leaf optical properties; and the other is for incident sky diffuse radiation with a non-uniform distribution. Comparison of the generalized model within the same canopy for both uniform and non-uniform incident diffuse radiation inputs shows smaller differences in general. However, there is a measurable difference between these radiation inputs for a canopy with high leaf angle. This indicates that the application of the two-stream model to a canopy with different adaxial and abaxial leaf optical properties will introduce non-negligible errors.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos. 40233034, 40575043the Chinese Academy of Sciences （KZCX3_SW_229）.
文摘In this paper, firstly, a simplified version （SGRTM） of the generalized layered radiative transfer model （GRTM） within the canopy, developed by us, is presented. It reduces the information requirement of inputted sky diffuse radiation, as well as of canopy morphology, and in turn saves computer resources. Results from the SGRTM agree perfectly with those of the GRTM. Secondly, by applying the linear superposition principle of the optics and by using the basic solutions of the GRTM for radiative transfer within the canopy under the condition of assumed zero soil reflectance, two sets of explicit analytical solutions of radiative transfer within the canopy with any soil reflectance magnitude are derived： one for incident diffuse, and the other for direct beam radiation. The explicit analytical solutions need two sets of basic solutions of canopy reflectance and transmittance under zero soil reflectance, run by the model for both diffuse and direct beam radiation. One set of basic solutions is the canopy reflectance αf （written as α1 for direct beam radiation） and transmittance βf （written as β1 for direction beam radiation） with zero soil reflectance for the downward radiation from above the canopy （i.e. sky）, and the other set is the canopy reflectance （αb） and transmittance βb for the upward radiation from below the canopy （i.e., ground）. Under the condition of the same plant architecture in the vertical layers, and the same leaf adaxial and abaxial optical properties in the canopies for the uniform diffuse radiation, the explicit solutions need only one set of basic solutions, because under this condition the two basic solutions are equal, i.e., αf = αb and βf = βb. Using the explicit analytical solutions, the fractions of any kind of incident solar radiation reflected from （defined as surface albedo, or canopy reflectance）, transmitted through （defined as canopy transmittance）, and absorbed by （defined as canopy absorptance） the canopy and other properties pertinent to the radiative transfer within the canopy can be estimated easily on the ground surface below the canopy （soil or snow surface） with any reflectance magnitudes. The simplified transfer model is proven to have a similar accuracy compared to the detailed model, as well as very efficient computing.
基金supported by the Natural Science Foundation of Sichuan Province(No.2022NSFSC1042)National Natural Science Foundation of China(No.52200051)+1 种基金Outstanding Youth Fund of Heilongjiang Natural Science Foundation(No.YQ2023E021)Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(No.HC202236).
文摘Thin-film composite(TFC)reverse osmosis(RO)membranes have attracted considerable attention in water treatment and desalination processes due to their specific separation advantages.Nevertheless,the trade-off effect between water flux and salt rejection poses huge challenges to further improvement in TFC RO membrane performance.Numerous research works have been dedicated to optimizing membrane fabrication and modification for addressing this issue.In the meantime,several reviews summarized these approaches.However,the existing reviews seldom analyzed these methods from a theoretical perspective and thus failed to offer effective optimization directions for the RO process from the root cause.In this review,we first propose a mass transfer model to facilitate a better understanding of the entire process of how water and solute permeate through RO membranes in detail,namely the migration process outside the membrane,the dissolution process on the membrane surface,and the diffusion process within the membrane.Thereafter,the water and salt mass transfer behaviors obtained from model deduction are comprehensively analyzed to provide potential guidelines for alleviating the trade-off effect between water flux and salt rejection in the RO process.Finally,inspired by the theoretical analysis and the accurate identification of existing bottlenecks,several promising strategies for both regulating RO membranes and optimizing operational conditions are proposed to further exploit the potential of RO membrane performance.This review is expected to guide the development of high-performance RO membranes from a mass transfer theory standpoint.
