A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,whic...A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,which is used for the scrambling,substitution and diffusion processes.The three-dimensional Fisher-Yates scrambling,S-box substitution and diffusion are employed for the first round of encryption.The chaotic sequence is adopted for secondary encryption to scramble the ciphertext obtained in the first round.Then,three-dimensional filter is applied to diffusion for further useful information hiding.The key to the algorithm is generated by the combination of hash value of plaintext image and the input parameters.It improves resisting ability of plaintext attacks.The security analysis shows that the algorithm is effective and efficient.It can resist common attacks.In addition,the good diffusion effect shows that the scheme can solve the differential attacks encountered in the transmission of medical images and has positive implications for future research.展开更多
Using the operator correspondence of the real and fictious modes in the thermo entangled state representation, wesolve the quantum master equation describing the diffusion channel and obtain the Kraus operator-sum rep...Using the operator correspondence of the real and fictious modes in the thermo entangled state representation, wesolve the quantum master equation describing the diffusion channel and obtain the Kraus operator-sum representation ofits analytical solution. we find that the pure coherent states evolve into the new mixed thermal superposed states in thediffusion channel. Also, we investigate the statistical properties of the initial coherent states and their entropy evolutions inthe diffusion channel, and find that the entropy evolutions are only related to the decay time and without the amplitudes ofthe initial coherent states.展开更多
Based on the Kraus operator-sum representation of the analytical solution of the diffusion equation,we obtain the evolution of a general linear state in the diffusion channel.Also,we study the quantum statistical prop...Based on the Kraus operator-sum representation of the analytical solution of the diffusion equation,we obtain the evolution of a general linear state in the diffusion channel.Also,we study the quantum statistical properties of the initial general linear state and its von-Neumann entropy evolution in the diffusion channel,especially find that the entropy evolution is influenced by the diffusion noise and the thermal parameter but without the displacement.展开更多
In this work,based on the role of pre-ionization of the non-uniform electric field and its effect of reducing the collisional ionization coefficient,a diffuse dielectric barrier discharge plasma is formed in the open ...In this work,based on the role of pre-ionization of the non-uniform electric field and its effect of reducing the collisional ionization coefficient,a diffuse dielectric barrier discharge plasma is formed in the open space outside the electrode structure at a lower voltage by constructing a three-dimensional non-uniform spatial electric field using a contact electrode structure.The air purification study is also carried out.Firstly,a contact electrode structure is constructed using a three-dimensional wire electrode.The distribution characteristics of the spatial electric field formed by this electrode structure are analyzed,and the effects of the non-uniform electric field and the different angles of the vertical wire on the generation of three-dimensional spatial diffuse discharge are investigated.Secondly,the copper foam contact electrode structure is constructed using copper foam material,and the effects of different mesh sizes on the electric field distribution are analyzed.The results show that as the mesh size of the copper foam becomes larger,a strong electric field region exists not only on the surface of the insulating layer,but also on the surface of the vertical wires inside the copper foam,i.e.,the strong electric field region shows a three-dimensional distribution.Besides,as the mesh size increases,the area of the vertical strong electric field also increases.However,the electric field strength on the surface of the insulating layer gradually decreases.Therefore,the appropriate mesh size can effectively increase the discharge area,which is conducive to improving the air purification efficiency.Finally,a highly permeable stacked electrode structure of multilayer wire-copper foam is designed.In combination with an ozone treatment catalyst,an air purification device is fabricated,and the air purification experiment is carried out.展开更多
BACKGROUND:Three-dimensional diffusion tensor tract(DTT)is the newest imaging to describe the structure of white matter fiber in three-dimensions,it has great significance in dividing the concrete anatomic site of gra...BACKGROUND:Three-dimensional diffusion tensor tract(DTT)is the newest imaging to describe the structure of white matter fiber in three-dimensions,it has great significance in dividing the concrete anatomic site of gray and white matter lesions,displaying the correlation with fibrous band and judging clinical prognosis,which is incomparable by other imagings.OBJECTIVE:To observe the conditions of corticospinal tract(CST)in acute cerebral ischemic stroke patients,and analyze the relationship between motor function and the severity of CST injury.DESIGN:A case-control observation.SETTING:Department of Medical Imaging,Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA.PARTICIPANTS:Fifteen patients with acute cerebral infarction were selected from Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from February to December in 2005.They all suffered from acute attack and motor disorder of hemiplegic limbs to different extent,and were conformed by CT or MRI.There were 9 males and 6 females,aging 16-87 years old,the median age was 51.7 years,and all were right handed.Fifteen right-handed normal subjects,who were matched by age and sex with the patients in the cerebral infarction group,were selected from the relatives of patients and physicians of the Imaging Department as the control group.All the subjects were informed and agreed with the study.METHODS:The patients with acute cerebral infarction and subjects in the control group received MR diffusion tensor imaging(DTI)with GE 1.5 T nuclear magnetic resonance system,fiber tracking with the software of dTV-Ⅱ.Fractional anisotropy(FA)maps and three-dimensional tractography of bilateral CST of all patients were created.Displacement,continuity and destroy of fibrous bands were observed.At the same time,muscle strength of ipsilateral hand of patients with cerebral infarction was measured with Brunnstrom standard.The correlation between the severity of CST injury and the muscle strength of ipsilateral hand was analyzed with spearman correlation analysis.MAIN OUTCOME MEASURES:①FA values in the infarcted sites and those in the contralateral corresponding sites of patients with cerebral infarction;②CST manifestations in the patients with cerebral infarction and the control group.RESULTS:All the 30 testees were involved in the analysis of results.①The FA values in infarcted sites of white matter were significantly lower than those in the contralateral ones(t=4.570,P<0.001).②In the control group,bilateral CST were reconstructed,they originated from precentral gyrus,went downwards to internal capsule,and extended to pontine and medulla oblongata,each fiber had good uniformity in continuous form.In the patients with cerebral infarction,the forms of contralateral CST were consistent with those in the control group with good continuity.Due to the involvement by the infarcted site to different extents,the ipsilateral CST manifested as continuous interruption and loss of uniformity in anatomic structure and form.The CST involvements were divided into three grades:integrated CST for grade 1(n=2);integrated CST but compressed or displaced for grade 2(n=5);interrupted CST for grade 3(n=8).③The severity of CST injury was obviously correlated with the muscle strength of the ipsilateral hand(r=0.888,P<0.05).CONCLUSION:①CST is injured to different extents in patients with acute cerebral infarction,and the severity of injury is associated with muscle strength.It is indicated that it can be used to judge the prognosis of rehabilitative treatment.②DTT can directly display the status of pyramidal tract more three-dimensionally.展开更多
A three-dimensional, first order turbulence closure, thermal diffusion model is described in this paper. The governing equations consist of an equation of continuity, three components of momentum, conservation equatio...A three-dimensional, first order turbulence closure, thermal diffusion model is described in this paper. The governing equations consist of an equation of continuity, three components of momentum, conservation equations for salt, temperature and subgridscale energy, and an equation of state. In the model, according to the hypothesis of Kolmogorov and Prandtl, the viscosity coefficient of turbulent flow of homogeneous fluid is related to the local turbulent energy, and the horizontal and vertical exchange coefficients of mass, heat and momentum are computed with the introduction of subgridscale turbulence energy. The governing equations are solved by finite difference techniques. This model is applied to the Jiaozhou bay to predict thermal pollution by the Huangdao power plant. An instantaneous tidal current field is computed, then the distribution of temperature increment is predicted, and finally the effect of wind stress on thermal discharge is discussed.展开更多
In this communication a generalized three- dimensional steady flow of a viscous fluid between two infinite parallel plates is considered. The flow is generated due to uniform stretching of the lower plate in x- and y-...In this communication a generalized three- dimensional steady flow of a viscous fluid between two infinite parallel plates is considered. The flow is generated due to uniform stretching of the lower plate in x- and y-directions. It is assumed that the upper plate is uniformly porous and is subjected to constant injection. The governing system is fully coupled and nonlinear in nature. A complete analytic solution which is uniformly valid for all values of the dimensionless parameters β Re and λ is obtained by using a purely analytic technique, namely the homotopy analysis method. Also the effects of the parameters β Re and λ on the velocity field are discussed through graphs.展开更多
The application of mathematical modeling to biological fluids is of utmost importance, as it has diverse applicationsin medicine. The peristaltic mechanism plays a crucial role in understanding numerous biological flo...The application of mathematical modeling to biological fluids is of utmost importance, as it has diverse applicationsin medicine. The peristaltic mechanism plays a crucial role in understanding numerous biological flows. In thispaper, we present a theoretical investigation of the double diffusion convection in the peristaltic transport of aPrandtl nanofluid through an asymmetric tapered channel under the combined action of thermal radiation andan induced magnetic field. The equations for the current flow scenario are developed, incorporating relevantassumptions, and considering the effect of viscous dissipation. The impact of thermal radiation and doublediffusion on public health is of particular interest. For instance, infrared radiation techniques have been used totreat various skin-related diseases and can also be employed as a measure of thermotherapy for some bones toenhance blood circulation, with radiation increasing blood flow by approximately 80%. To solve the governingequations, we employ a numerical method with the aid of symbolic software such as Mathematica and MATLAB.The velocity, magnetic force function, pressure rise, temperature, solute (species) concentration, and nanoparticlevolume fraction profiles are analytically derived and graphically displayed. The results outcomes are compared withthe findings of limiting situations for verification.展开更多
Silicon(Si)is regarded as a promising anode material for next-generation lithium-ion batteries due to its ultrahigh theoretical capacity.However,the drastic volume change and the continuous solid electrolyte interphas...Silicon(Si)is regarded as a promising anode material for next-generation lithium-ion batteries due to its ultrahigh theoretical capacity.However,the drastic volume change and the continuous solid electrolyte interphase(SEI)formation during the lithiation/delithiation process seriously hinder its practical application as commercial anodes.Herein,macrocyclic betacyclodextrin(β-CD)has been designed as the diffusion channel for lithium ions at the molecular scale.The diameter of molecular channel is approximately comparable with the solvated lithium ions,which enables the transport of lithium ions and prevents the penetration of solvent molecules.Moreover,the addition ofβ-CD changes the formation behavior of SEI layer and stabilizes the Si nanoparticles.The enhanced electrochemical performances in terms of fast kinetics and improved stability have been achieved.The Si anode with the particularly selected lithium-ion diffusion channel and stabilized SEI layer exhibits a high reversible capability of 2562 m Ah g-1 after 50 cycles at the current density of 500 m A g-1,1944 m Ah g-1 after 200 cycles at the current density of 1 A g-1,and high rate performance.The novel strategy of molecular channel for lithium-ion diffusion offers new insights into the design of alloy-typed anode electrodes with high capacity for lithium-ion batteries.展开更多
The through silicon via （TSV） technology has proven to be the critical enabler to realize a three-dimensional （3D） gigscale system with higher performance but shorter interconnect length. However, the received dig...The through silicon via （TSV） technology has proven to be the critical enabler to realize a three-dimensional （3D） gigscale system with higher performance but shorter interconnect length. However, the received digital signal after trans- mission through a TSV channel, composed of redistribution layers （RDLs）, TSVs, and bumps, is degraded at a high data-rate due to the non-idealities of the channel. We propose the Chebyshev multisection transformers to reduce the signal reflec- tion of TSV channel when operating frequency goes up to 20 GHz, by which signal reflection coefficient （$11） and signal transmission coefficient （$21） are improved remarkably by 150% and 73.3%, respectively. Both the time delay and power dissipation are also reduced by 4% and 13.3%, respectively. The resistance-inductance-conductance-capacitance （RLGC） elements of the TSV channel are iterated from scattering （S）-parameters, and the proposed method of weakening the signal reflection is verified using high frequency simulator structure （HFSS） simulation software by Ansoft.展开更多
Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds she...Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds shear stress distributions show that the velocity and velocity fluctuation in the transverse direction are not negligible. Moreover, the bursting process is investigated using the three-dimensional quadrant analysis, which is more accurate than using the traditional two-dimensional quadrant analysis for the meandering channel. It is obtained from the experimental results that the internal group of events occurs more frequently than the external group, particularly the internal ejection and internal sweep events. In addition, the transition probabilities of the movements, which are defined as the changes of events from the current situation to the next situation in a time series, show that the stable organizations of events are the most possible movements, whereas the cross organizations of events have the least possible movements.展开更多
A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport...A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport path of lithium ions and electrons, but also reduce the side effects and withstand the structural strain in the process of repetitive Li~+ intercalation/deintercalation. In this work, an e fficient method for designing the hollow LNMO microsphere with 3 D channels structure by using polyethylene oxide(PEO) as soft template agent assisted solvothermal method is proposed. Experimental results indicate that PEO can make the reagents mingle evenly and nucleate slowly in the solvothermal process, thus obtaining a homogeneous distribution of carbonate precursors. In the final LNMO products, the hollow 3 D channels structure obtained by the decomposition of PEO and carbonate precursor in the calcination can provide abundant electroactive zones and electron/ion transport paths during the charge/discharge process, which benefits to improve the cycling performance and rate capability. The LNMO prepared by adding 1 g PEO possesses the most outstanding electrochemical performance, which presented an excellent discharge capacity of 143.1 mAh g~(-1) at 0.1 C and with a capacity retention of 92.2% after 100 cycles at 1 C. The superior performance attributed to the 3 D channels structure of hollow microspheres, which provide uninterrupted conductive systems and therefore achieve the stable transfer for electron/ion.展开更多
Numerical simulation using the finite differential method was carried out to analyze the diffusion of an impulse sample in the micro-channel driven by electroosmosis. The results show that the electrical field strengt...Numerical simulation using the finite differential method was carried out to analyze the diffusion of an impulse sample in the micro-channel driven by electroosmosis. The results show that the electrical field strength applied externally and the concentration of buffer solution play a significant role in the diffusion of sample, however, hydraulic diameter and aspect ratio of height to width of channel play a small role in it. Weakening the electrical field strength applied externally and the concentration of buffer solution properly can prevent the sample band from broadening effectively, and promote the efficiency of testing and separation as well as keep a faster speed of transport. The conclusions are helpful to the optimal design for micro-channel.展开更多
On September 10, 2015, unprecedented flood was occurred in Kinugawa River basin located on eastern Japan. It inundated 40 km2 of flood plain in Joso city, Ibaraki Prefecture, and more than 4000 people there called for...On September 10, 2015, unprecedented flood was occurred in Kinugawa River basin located on eastern Japan. It inundated 40 km2 of flood plain in Joso city, Ibaraki Prefecture, and more than 4000 people there called for help despite supposedly having sufficient time to evacuate. Some said that small initial flood before main severe flood arrived made them make a mistake in deciding whether to evacuate or stay there, despite having to actually evacuate in reality. This study focused on flood behaviour in this area, in particular, the effect of a small drainage channel lying on the flood plain which caused fast flood diffusion in case of occurring huge overflowing. Field investigations starting on time of the disaster with high-resolution positioning system were conducted to obtain spatial maps of flood depth and height. For appropriate modelling of the effect of small channel, we applied simulation model coupling 1-dimensional (1D) and 2-dimensional (2D) hydraulic scheme on the field and compared results from the 1D/2D coupled model and model without 1D scheme. The models provided information that the flood could reach 4 hours earlier to the city central of Joso city comparing in case of model without 1D scheme. The water depth rose irregularly and it was more confusing and difficult for the victims to make appropriate evacuation act.展开更多
We find the time evolution law of a negative binomial optical field in a diffusion channel. We reveal that by adjusting the diffusion parameter, the photon number can be controlled. Therefore, the diffusion process ca...We find the time evolution law of a negative binomial optical field in a diffusion channel. We reveal that by adjusting the diffusion parameter, the photon number can be controlled. Therefore, the diffusion process can be considered a quantum controlling scheme through photon addition.展开更多
Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments...Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major challenges associated with constructing phased array coils for monkeys are the variation in head size and space constraints. Here, we apply phased array technology to a 4-channel phased array coil capable of improving the resolution and image quality of full brain awake monkey fMRI and diffusion MRI experiments. The phased array coil is that can adapt to different rhesus monkey head sizes (ages 4-8) and fits in the limited space provided by monkey stereotactic equipment and provides SNR gains in primary visual cortex and anatomical accuracy in conjunction with parallel imaging and improves resolution in fMRI experiments by a factor of 2 (1.25 mm to 1.0 mm isotropic) and diffusion MRI experiments by a factor of 4 (1.5 mm to 0.9 mm isotropic).展开更多
Diffusion of colloidal particles in microchannels has been extensively investigated,where the channel wall is either a no-slip or a slip-passive boundary.However,in the context of active fluids,driving boundary walls ...Diffusion of colloidal particles in microchannels has been extensively investigated,where the channel wall is either a no-slip or a slip-passive boundary.However,in the context of active fluids,driving boundary walls are ubiquitous and are expected to have a substantial effect on the particle dynamics.By mesoscale simulations,we study the diffusion of a chemically active colloidal particle in composite channels,which are constructed by alternately arranging the no-slip and diffusio-osmotic boundary walls.In this case,the chemical reaction catalyzed by the active colloidal particle creates a local chemical gradient along the channel wall,which drives a diffusio-osmotic flow parallel to the wall.We show that the diffusio-osmotic flow can significantly change the spatial distribution and diffusion dynamics of the colloidal particle in the composite channels.By modulating the surface properties of the channel wall,we can achieve different patterns of colloidal position distribution.The findings thus propose a novel possibility to manipulate colloidal diffusion in microfluidics,and highlight the importance of driving boundary walls in dynamics of colloidal particles in microchannels.展开更多
An analysis is performed for the hydromagnetic second grade fluid flow between two horizontal plates in a rotating system in the presence of a magnetic field. The lower sheet is considered to be a stretching sheet, an...An analysis is performed for the hydromagnetic second grade fluid flow between two horizontal plates in a rotating system in the presence of a magnetic field. The lower sheet is considered to be a stretching sheet, and the upper sheet is a porous solid plate. By suitable transformations, the equations of conservation of mass and momentum are reduced to a system of coupled non-linear ordinary differential equations. A series of solutions to this coupled non-linear system are obtained by a powerful analytic technique, i.e., the homotopy analysis method （HAM）. The results are presented with graphs. The effects of non-dimensional parameters R, A, M2, a, and K2 on the velocity field are discussed in detail.展开更多
We explore the time evolution law of a two-mode squeezed light field(pure state)passing through twin diffusion channels,and we find that the final state is a squeezed chaotic light field(mixed state)with entanglement,...We explore the time evolution law of a two-mode squeezed light field(pure state)passing through twin diffusion channels,and we find that the final state is a squeezed chaotic light field(mixed state)with entanglement,which shows that even though the two channels are independent of each other,since the two modes of the initial state are entangled with each other,the final state remains entangled.Nevertheless,although the squeezing(entanglement)between the two modes is weakened after the diffusion,it is not completely removed.We also highlight the law of photon number evolution.In the calculation process used in this paper,we make full use of the summation method within the ordered product of operators and the generating function formula for two-variable Hermite polynomials.展开更多
In this study,it is proposed that the diffusion least mean square(LMS)algorithm can be improved by applying the fractional order signal processing methodologies.Application of Caputo’s fractional derivatives are cons...In this study,it is proposed that the diffusion least mean square(LMS)algorithm can be improved by applying the fractional order signal processing methodologies.Application of Caputo’s fractional derivatives are considered in the optimization of cost function.It is suggested to derive a fractional order variant of the diffusion LMS algorithm.The applicability is tested for the estimation of channel parameters in a distributed environment consisting of randomly distributed sensors communicating through wireless medium.The topology of the network is selected such that a smaller number of nodes are informed.In the network,a random sleep strategy is followed to conserve the transmission power at the nodes.The proposed fractional ordermodified diffusionLMS algorithms are applied in the two configurations of combine-then-adapt and adapt-then-combine.The average squared error performance of the proposed algorithms along with its traditional counterparts are evaluated for the estimation of the Rayleigh channel parameters.Amathematical proof of convergence is provided showing that the addition of the nonlinear term resulting from fractional derivatives helps adjusts the autocorrelation matrix in such a way that the spread of its eigenvalues decreases.This increases the convergence as well as the steady state response even for the larger step sizes.Experimental results are shown for different number of nodes and fractional orders.The simulation results establish that the accuracy of the proposed scheme is far better than its classical counterparts,therefore,helps better solves the channel gains estimation problem in a distributed wireless environment.The algorithm has the potential to be applied in other applications related to learning and adaptation.展开更多
文摘A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,which is used for the scrambling,substitution and diffusion processes.The three-dimensional Fisher-Yates scrambling,S-box substitution and diffusion are employed for the first round of encryption.The chaotic sequence is adopted for secondary encryption to scramble the ciphertext obtained in the first round.Then,three-dimensional filter is applied to diffusion for further useful information hiding.The key to the algorithm is generated by the combination of hash value of plaintext image and the input parameters.It improves resisting ability of plaintext attacks.The security analysis shows that the algorithm is effective and efficient.It can resist common attacks.In addition,the good diffusion effect shows that the scheme can solve the differential attacks encountered in the transmission of medical images and has positive implications for future research.
基金Collaborative Innovation Project of University,Anhui Province(Grant No.GXXT-2022-088).
文摘Using the operator correspondence of the real and fictious modes in the thermo entangled state representation, wesolve the quantum master equation describing the diffusion channel and obtain the Kraus operator-sum representation ofits analytical solution. we find that the pure coherent states evolve into the new mixed thermal superposed states in thediffusion channel. Also, we investigate the statistical properties of the initial coherent states and their entropy evolutions inthe diffusion channel, and find that the entropy evolutions are only related to the decay time and without the amplitudes ofthe initial coherent states.
基金Project supported by the Natural Science Foundation of Hainan Province,China(Grant Nos.621RC741 and 622RC668)。
文摘Based on the Kraus operator-sum representation of the analytical solution of the diffusion equation,we obtain the evolution of a general linear state in the diffusion channel.Also,we study the quantum statistical properties of the initial general linear state and its von-Neumann entropy evolution in the diffusion channel,especially find that the entropy evolution is influenced by the diffusion noise and the thermal parameter but without the displacement.
基金supported by the Fundamental Research Funds for the Central Universities(No.2022YJS094)。
文摘In this work,based on the role of pre-ionization of the non-uniform electric field and its effect of reducing the collisional ionization coefficient,a diffuse dielectric barrier discharge plasma is formed in the open space outside the electrode structure at a lower voltage by constructing a three-dimensional non-uniform spatial electric field using a contact electrode structure.The air purification study is also carried out.Firstly,a contact electrode structure is constructed using a three-dimensional wire electrode.The distribution characteristics of the spatial electric field formed by this electrode structure are analyzed,and the effects of the non-uniform electric field and the different angles of the vertical wire on the generation of three-dimensional spatial diffuse discharge are investigated.Secondly,the copper foam contact electrode structure is constructed using copper foam material,and the effects of different mesh sizes on the electric field distribution are analyzed.The results show that as the mesh size of the copper foam becomes larger,a strong electric field region exists not only on the surface of the insulating layer,but also on the surface of the vertical wires inside the copper foam,i.e.,the strong electric field region shows a three-dimensional distribution.Besides,as the mesh size increases,the area of the vertical strong electric field also increases.However,the electric field strength on the surface of the insulating layer gradually decreases.Therefore,the appropriate mesh size can effectively increase the discharge area,which is conducive to improving the air purification efficiency.Finally,a highly permeable stacked electrode structure of multilayer wire-copper foam is designed.In combination with an ozone treatment catalyst,an air purification device is fabricated,and the air purification experiment is carried out.
文摘BACKGROUND:Three-dimensional diffusion tensor tract(DTT)is the newest imaging to describe the structure of white matter fiber in three-dimensions,it has great significance in dividing the concrete anatomic site of gray and white matter lesions,displaying the correlation with fibrous band and judging clinical prognosis,which is incomparable by other imagings.OBJECTIVE:To observe the conditions of corticospinal tract(CST)in acute cerebral ischemic stroke patients,and analyze the relationship between motor function and the severity of CST injury.DESIGN:A case-control observation.SETTING:Department of Medical Imaging,Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA.PARTICIPANTS:Fifteen patients with acute cerebral infarction were selected from Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from February to December in 2005.They all suffered from acute attack and motor disorder of hemiplegic limbs to different extent,and were conformed by CT or MRI.There were 9 males and 6 females,aging 16-87 years old,the median age was 51.7 years,and all were right handed.Fifteen right-handed normal subjects,who were matched by age and sex with the patients in the cerebral infarction group,were selected from the relatives of patients and physicians of the Imaging Department as the control group.All the subjects were informed and agreed with the study.METHODS:The patients with acute cerebral infarction and subjects in the control group received MR diffusion tensor imaging(DTI)with GE 1.5 T nuclear magnetic resonance system,fiber tracking with the software of dTV-Ⅱ.Fractional anisotropy(FA)maps and three-dimensional tractography of bilateral CST of all patients were created.Displacement,continuity and destroy of fibrous bands were observed.At the same time,muscle strength of ipsilateral hand of patients with cerebral infarction was measured with Brunnstrom standard.The correlation between the severity of CST injury and the muscle strength of ipsilateral hand was analyzed with spearman correlation analysis.MAIN OUTCOME MEASURES:①FA values in the infarcted sites and those in the contralateral corresponding sites of patients with cerebral infarction;②CST manifestations in the patients with cerebral infarction and the control group.RESULTS:All the 30 testees were involved in the analysis of results.①The FA values in infarcted sites of white matter were significantly lower than those in the contralateral ones(t=4.570,P<0.001).②In the control group,bilateral CST were reconstructed,they originated from precentral gyrus,went downwards to internal capsule,and extended to pontine and medulla oblongata,each fiber had good uniformity in continuous form.In the patients with cerebral infarction,the forms of contralateral CST were consistent with those in the control group with good continuity.Due to the involvement by the infarcted site to different extents,the ipsilateral CST manifested as continuous interruption and loss of uniformity in anatomic structure and form.The CST involvements were divided into three grades:integrated CST for grade 1(n=2);integrated CST but compressed or displaced for grade 2(n=5);interrupted CST for grade 3(n=8).③The severity of CST injury was obviously correlated with the muscle strength of the ipsilateral hand(r=0.888,P<0.05).CONCLUSION:①CST is injured to different extents in patients with acute cerebral infarction,and the severity of injury is associated with muscle strength.It is indicated that it can be used to judge the prognosis of rehabilitative treatment.②DTT can directly display the status of pyramidal tract more three-dimensionally.
基金This project was financially supported by the National Committee of Science and Technology Grants/903-85-08-05
文摘A three-dimensional, first order turbulence closure, thermal diffusion model is described in this paper. The governing equations consist of an equation of continuity, three components of momentum, conservation equations for salt, temperature and subgridscale energy, and an equation of state. In the model, according to the hypothesis of Kolmogorov and Prandtl, the viscosity coefficient of turbulent flow of homogeneous fluid is related to the local turbulent energy, and the horizontal and vertical exchange coefficients of mass, heat and momentum are computed with the introduction of subgridscale turbulence energy. The governing equations are solved by finite difference techniques. This model is applied to the Jiaozhou bay to predict thermal pollution by the Huangdao power plant. An instantaneous tidal current field is computed, then the distribution of temperature increment is predicted, and finally the effect of wind stress on thermal discharge is discussed.
文摘In this communication a generalized three- dimensional steady flow of a viscous fluid between two infinite parallel plates is considered. The flow is generated due to uniform stretching of the lower plate in x- and y-directions. It is assumed that the upper plate is uniformly porous and is subjected to constant injection. The governing system is fully coupled and nonlinear in nature. A complete analytic solution which is uniformly valid for all values of the dimensionless parameters β Re and λ is obtained by using a purely analytic technique, namely the homotopy analysis method. Also the effects of the parameters β Re and λ on the velocity field are discussed through graphs.
基金Institutional Fund Projects under No.(IFP-A-2022-2-5-24)by Ministry of Education and University of Hafr Al Batin,Saudi Arabia.
文摘The application of mathematical modeling to biological fluids is of utmost importance, as it has diverse applicationsin medicine. The peristaltic mechanism plays a crucial role in understanding numerous biological flows. In thispaper, we present a theoretical investigation of the double diffusion convection in the peristaltic transport of aPrandtl nanofluid through an asymmetric tapered channel under the combined action of thermal radiation andan induced magnetic field. The equations for the current flow scenario are developed, incorporating relevantassumptions, and considering the effect of viscous dissipation. The impact of thermal radiation and doublediffusion on public health is of particular interest. For instance, infrared radiation techniques have been used totreat various skin-related diseases and can also be employed as a measure of thermotherapy for some bones toenhance blood circulation, with radiation increasing blood flow by approximately 80%. To solve the governingequations, we employ a numerical method with the aid of symbolic software such as Mathematica and MATLAB.The velocity, magnetic force function, pressure rise, temperature, solute (species) concentration, and nanoparticlevolume fraction profiles are analytically derived and graphically displayed. The results outcomes are compared withthe findings of limiting situations for verification.
基金financial support by the National Natural Science Foundation of China(51874357,51872333)Innovative Research Group of Hunan Provincial Natural Science Foundation of China(2019JJ10006)+3 种基金the support from the 100 Talented Program of Hunan Province“Huxiang high-level talents”program(2019RS1007)support from Shenghua Scholar Program of Central South Universitysupport from JSPS KAKENNHI(18H03869)
文摘Silicon(Si)is regarded as a promising anode material for next-generation lithium-ion batteries due to its ultrahigh theoretical capacity.However,the drastic volume change and the continuous solid electrolyte interphase(SEI)formation during the lithiation/delithiation process seriously hinder its practical application as commercial anodes.Herein,macrocyclic betacyclodextrin(β-CD)has been designed as the diffusion channel for lithium ions at the molecular scale.The diameter of molecular channel is approximately comparable with the solvated lithium ions,which enables the transport of lithium ions and prevents the penetration of solvent molecules.Moreover,the addition ofβ-CD changes the formation behavior of SEI layer and stabilizes the Si nanoparticles.The enhanced electrochemical performances in terms of fast kinetics and improved stability have been achieved.The Si anode with the particularly selected lithium-ion diffusion channel and stabilized SEI layer exhibits a high reversible capability of 2562 m Ah g-1 after 50 cycles at the current density of 500 m A g-1,1944 m Ah g-1 after 200 cycles at the current density of 1 A g-1,and high rate performance.The novel strategy of molecular channel for lithium-ion diffusion offers new insights into the design of alloy-typed anode electrodes with high capacity for lithium-ion batteries.
基金Project supported by the National Natural Science Foundation of China(Grant No.61204044)
文摘The through silicon via （TSV） technology has proven to be the critical enabler to realize a three-dimensional （3D） gigscale system with higher performance but shorter interconnect length. However, the received digital signal after trans- mission through a TSV channel, composed of redistribution layers （RDLs）, TSVs, and bumps, is degraded at a high data-rate due to the non-idealities of the channel. We propose the Chebyshev multisection transformers to reduce the signal reflec- tion of TSV channel when operating frequency goes up to 20 GHz, by which signal reflection coefficient （$11） and signal transmission coefficient （$21） are improved remarkably by 150% and 73.3%, respectively. Both the time delay and power dissipation are also reduced by 4% and 13.3%, respectively. The resistance-inductance-conductance-capacitance （RLGC） elements of the TSV channel are iterated from scattering （S）-parameters, and the proposed method of weakening the signal reflection is verified using high frequency simulator structure （HFSS） simulation software by Ansoft.
基金Supported by National Natural Science Foundation of China(No.50979066 and No.51279124)Foundation for Creative Research Groups of National Natural Science Foundation of China(No.51021004)
文摘Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds shear stress distributions show that the velocity and velocity fluctuation in the transverse direction are not negligible. Moreover, the bursting process is investigated using the three-dimensional quadrant analysis, which is more accurate than using the traditional two-dimensional quadrant analysis for the meandering channel. It is obtained from the experimental results that the internal group of events occurs more frequently than the external group, particularly the internal ejection and internal sweep events. In addition, the transition probabilities of the movements, which are defined as the changes of events from the current situation to the next situation in a time series, show that the stable organizations of events are the most possible movements, whereas the cross organizations of events have the least possible movements.
基金funded by the National Natural Science Foundation of China(No.21776051)the Natural Science Foundations of Guangdong(No.2018A030313423)。
文摘A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport path of lithium ions and electrons, but also reduce the side effects and withstand the structural strain in the process of repetitive Li~+ intercalation/deintercalation. In this work, an e fficient method for designing the hollow LNMO microsphere with 3 D channels structure by using polyethylene oxide(PEO) as soft template agent assisted solvothermal method is proposed. Experimental results indicate that PEO can make the reagents mingle evenly and nucleate slowly in the solvothermal process, thus obtaining a homogeneous distribution of carbonate precursors. In the final LNMO products, the hollow 3 D channels structure obtained by the decomposition of PEO and carbonate precursor in the calcination can provide abundant electroactive zones and electron/ion transport paths during the charge/discharge process, which benefits to improve the cycling performance and rate capability. The LNMO prepared by adding 1 g PEO possesses the most outstanding electrochemical performance, which presented an excellent discharge capacity of 143.1 mAh g~(-1) at 0.1 C and with a capacity retention of 92.2% after 100 cycles at 1 C. The superior performance attributed to the 3 D channels structure of hollow microspheres, which provide uninterrupted conductive systems and therefore achieve the stable transfer for electron/ion.
基金Project supported by the National Natural Science Foundation of China (No.20299030)
文摘Numerical simulation using the finite differential method was carried out to analyze the diffusion of an impulse sample in the micro-channel driven by electroosmosis. The results show that the electrical field strength applied externally and the concentration of buffer solution play a significant role in the diffusion of sample, however, hydraulic diameter and aspect ratio of height to width of channel play a small role in it. Weakening the electrical field strength applied externally and the concentration of buffer solution properly can prevent the sample band from broadening effectively, and promote the efficiency of testing and separation as well as keep a faster speed of transport. The conclusions are helpful to the optimal design for micro-channel.
文摘On September 10, 2015, unprecedented flood was occurred in Kinugawa River basin located on eastern Japan. It inundated 40 km2 of flood plain in Joso city, Ibaraki Prefecture, and more than 4000 people there called for help despite supposedly having sufficient time to evacuate. Some said that small initial flood before main severe flood arrived made them make a mistake in deciding whether to evacuate or stay there, despite having to actually evacuate in reality. This study focused on flood behaviour in this area, in particular, the effect of a small drainage channel lying on the flood plain which caused fast flood diffusion in case of occurring huge overflowing. Field investigations starting on time of the disaster with high-resolution positioning system were conducted to obtain spatial maps of flood depth and height. For appropriate modelling of the effect of small channel, we applied simulation model coupling 1-dimensional (1D) and 2-dimensional (2D) hydraulic scheme on the field and compared results from the 1D/2D coupled model and model without 1D scheme. The models provided information that the flood could reach 4 hours earlier to the city central of Joso city comparing in case of model without 1D scheme. The water depth rose irregularly and it was more confusing and difficult for the victims to make appropriate evacuation act.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB922103)the National Natural Science Foundation of China(Grant Nos.11175113,11274104,and 11404108)the Natural Science Foundation of Hubei Province,China(Grant No.2011CDA021)
文摘We find the time evolution law of a negative binomial optical field in a diffusion channel. We reveal that by adjusting the diffusion parameter, the photon number can be controlled. Therefore, the diffusion process can be considered a quantum controlling scheme through photon addition.
文摘Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major challenges associated with constructing phased array coils for monkeys are the variation in head size and space constraints. Here, we apply phased array technology to a 4-channel phased array coil capable of improving the resolution and image quality of full brain awake monkey fMRI and diffusion MRI experiments. The phased array coil is that can adapt to different rhesus monkey head sizes (ages 4-8) and fits in the limited space provided by monkey stereotactic equipment and provides SNR gains in primary visual cortex and anatomical accuracy in conjunction with parallel imaging and improves resolution in fMRI experiments by a factor of 2 (1.25 mm to 1.0 mm isotropic) and diffusion MRI experiments by a factor of 4 (1.5 mm to 0.9 mm isotropic).
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11874397,11674365,and 11774393)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33000000)。
文摘Diffusion of colloidal particles in microchannels has been extensively investigated,where the channel wall is either a no-slip or a slip-passive boundary.However,in the context of active fluids,driving boundary walls are ubiquitous and are expected to have a substantial effect on the particle dynamics.By mesoscale simulations,we study the diffusion of a chemically active colloidal particle in composite channels,which are constructed by alternately arranging the no-slip and diffusio-osmotic boundary walls.In this case,the chemical reaction catalyzed by the active colloidal particle creates a local chemical gradient along the channel wall,which drives a diffusio-osmotic flow parallel to the wall.We show that the diffusio-osmotic flow can significantly change the spatial distribution and diffusion dynamics of the colloidal particle in the composite channels.By modulating the surface properties of the channel wall,we can achieve different patterns of colloidal position distribution.The findings thus propose a novel possibility to manipulate colloidal diffusion in microfluidics,and highlight the importance of driving boundary walls in dynamics of colloidal particles in microchannels.
文摘An analysis is performed for the hydromagnetic second grade fluid flow between two horizontal plates in a rotating system in the presence of a magnetic field. The lower sheet is considered to be a stretching sheet, and the upper sheet is a porous solid plate. By suitable transformations, the equations of conservation of mass and momentum are reduced to a system of coupled non-linear ordinary differential equations. A series of solutions to this coupled non-linear system are obtained by a powerful analytic technique, i.e., the homotopy analysis method （HAM）. The results are presented with graphs. The effects of non-dimensional parameters R, A, M2, a, and K2 on the velocity field are discussed in detail.
基金supported by the National Natural Science Foundation of China(Grant No.11775208)the Foundation for Young Talents in College of Anhui Province,China(Grant No.gxyq2019077)the Natural Science Foundation of the Anhui Higher Education Institutions of China(Grant Nos.KJ2019A0688 and KJ2020A0638)。
文摘We explore the time evolution law of a two-mode squeezed light field(pure state)passing through twin diffusion channels,and we find that the final state is a squeezed chaotic light field(mixed state)with entanglement,which shows that even though the two channels are independent of each other,since the two modes of the initial state are entangled with each other,the final state remains entangled.Nevertheless,although the squeezing(entanglement)between the two modes is weakened after the diffusion,it is not completely removed.We also highlight the law of photon number evolution.In the calculation process used in this paper,we make full use of the summation method within the ordered product of operators and the generating function formula for two-variable Hermite polynomials.
文摘In this study,it is proposed that the diffusion least mean square(LMS)algorithm can be improved by applying the fractional order signal processing methodologies.Application of Caputo’s fractional derivatives are considered in the optimization of cost function.It is suggested to derive a fractional order variant of the diffusion LMS algorithm.The applicability is tested for the estimation of channel parameters in a distributed environment consisting of randomly distributed sensors communicating through wireless medium.The topology of the network is selected such that a smaller number of nodes are informed.In the network,a random sleep strategy is followed to conserve the transmission power at the nodes.The proposed fractional ordermodified diffusionLMS algorithms are applied in the two configurations of combine-then-adapt and adapt-then-combine.The average squared error performance of the proposed algorithms along with its traditional counterparts are evaluated for the estimation of the Rayleigh channel parameters.Amathematical proof of convergence is provided showing that the addition of the nonlinear term resulting from fractional derivatives helps adjusts the autocorrelation matrix in such a way that the spread of its eigenvalues decreases.This increases the convergence as well as the steady state response even for the larger step sizes.Experimental results are shown for different number of nodes and fractional orders.The simulation results establish that the accuracy of the proposed scheme is far better than its classical counterparts,therefore,helps better solves the channel gains estimation problem in a distributed wireless environment.The algorithm has the potential to be applied in other applications related to learning and adaptation.
