Drone logistics is a novel method of distribution that will become prevalent.The advantageous location of the logistics hub enables quicker customer deliveries and lower fuel consumption,resulting in cost savings for ...Drone logistics is a novel method of distribution that will become prevalent.The advantageous location of the logistics hub enables quicker customer deliveries and lower fuel consumption,resulting in cost savings for the company’s transportation operations.Logistics firms must discern the ideal location for establishing a logistics hub,which is challenging due to the simplicity of existing models and the intricate delivery factors.To simulate the drone logistics environment,this study presents a new mathematical model.The model not only retains the aspects of the current models,but also considers the degree of transportation difficulty from the logistics hub to the village,the capacity of drones for transportation,and the distribution of logistics hub locations.Moreover,this paper proposes an improved particle swarm optimization(PSO)algorithm which is a diversity-based hybrid PSO(DHPSO)algorithm to solve this model.In DHPSO,the Gaussian random walk can enhance global search in the model space,while the bubble-net attacking strategy can speed convergence.Besides,Archimedes spiral strategy is employed to overcome the local optima trap in the model and improve the exploitation of the algorithm.DHPSO maintains a balance between exploration and exploitation while better defining the distribution of logistics hub locations Numerical experiments show that the newly proposed model always achieves better locations than the current model.Comparing DHPSO with other state-of-the-art intelligent algorithms,the efficiency of the scheme can be improved by 42.58%.This means that logistics companies can reduce distribution costs and consumers can enjoy a more enjoyable shopping experience by using DHPSO’s location selection.All the results show the location of the drone logistics hub is solved by DHPSO effectively.展开更多
The concept of the carbon cycle in the old goaf of a coal mine based on CO_(2)utilization and storage was put forward adhering to the principle of low-carbon development,utilization of space resources in old goafs,and...The concept of the carbon cycle in the old goaf of a coal mine based on CO_(2)utilization and storage was put forward adhering to the principle of low-carbon development,utilization of space resources in old goafs,and associated gas resources development.Firstly,the evolution characteristics of overburden fissures in the goaf of the case was studied using a two-dimensional physical similarity simulation test,the sealing performance of the caprocks after stabilization was analyzed,and the fissures were counted and classi-fied.Then,the process of gaseous CO_(2)injection in the connected fissure was simulated by Ansys Fluent software,and the migration law and distribution characteristics of CO_(2)under the condition of gaseous CO_(2)injection were analyzed.Finally,the estimation models of free CO_(2)storage capacity in the old goaf were constructed considering the proportion of connected fissure and the effectiveness of CO_(2)injection.The CO_(2)storage capacity in the old goaf of the case coal mine was estimated.The results showed that a caprock group of“hard-thickness low-permeability hard-thickness”was formed after the caprock-fissures system in the goaf of the case tended to be stable vertically.The connected fissure,occlude cracks,and micro-fractures in the goaf accounted for 85.5%,8.5%,and 6%of the total fissures,respectively.Gaseous CO_(2)first migrated to the bottom of the connected fissure after CO_(2)was injected into the goaf,then spread horizontally along the bottom of the connected fissure after reaching the bottom,and finally spread longitudinally after filling the bottom of the entire connected fissure.The theoretical and effective storage capacities of free CO_(2)at normal temperature and pressure in the old goaf of the case were 9757 and 7477 t,respectively.The effective storage capacity of free CO_(2)at normal temperature and pressure in the old goaf after all minefield mined was 193404 t.The research can provide some reference for the coal mining industry to help the goal of“carbon peaking and carbon neutrality”.展开更多
Accurate traffic pattern prediction in largescale networks is of great importance for intelligent system management and automatic resource allocation.System-level mobile traffic forecasting has significant challenges ...Accurate traffic pattern prediction in largescale networks is of great importance for intelligent system management and automatic resource allocation.System-level mobile traffic forecasting has significant challenges due to the tremendous temporal and spatial dynamics introduced by diverse Internet user behaviors and frequent traffic migration.Spatialtemporal graph modeling is an efficient approach for analyzing the spatial relations and temporal trends of mobile traffic in a large system.Previous research may not reflect the optimal dependency by ignoring inter-base station dependency or pre-determining the explicit geological distance as the interrelationship of base stations.To overcome the limitations of graph structure,this study proposes an adaptive graph convolutional network(AGCN)that captures the latent spatial dependency by developing self-adaptive dependency matrices and acquires temporal dependency using recurrent neural networks.Evaluated on two mobile network datasets,the experimental results demonstrate that this method outperforms other baselines and reduces the mean absolute error by 3.7%and 5.6%compared to time-series based approaches.展开更多
We report a case of a 74-year-old female with hypopharyngeal cancer who developed a pharyngoesophageal fistula and neck skin defect after total laryngectomy.To reconstruct the hypopharynx,upper esophagus,and neck skin...We report a case of a 74-year-old female with hypopharyngeal cancer who developed a pharyngoesophageal fistula and neck skin defect after total laryngectomy.To reconstruct the hypopharynx,upper esophagus,and neck skin defect,we used a supraclavicular artery island flap(SCAIF)for one-stage reconstruction.SCAIF offered reliable blood supply,minimal donor site morbidity,and excellent cosmetic outcomes.Although a small portion of the flap developed necrosis,it healed without surgical intervention.We also conducted a literature review of previously published articles on SCAIF for head and neck reconstruction.Our review highlights the advantages and limitations of SCAIF as a promising option for one-stage reconstruction of complex hypopharyngeal and upper esophageal defects with neck skin defects in selected patients.This case report provides valuable insights into the use of SCAIF in complex head and neck reconstructions,which can help improve patient outcomes and quality of life.展开更多
In this paper,standard and economical cascadic multigrid methods are considered for solving the algebraic systems resulting from the mortar finite element methods. Both cascadic multigrid methods do not need full elli...In this paper,standard and economical cascadic multigrid methods are considered for solving the algebraic systems resulting from the mortar finite element methods. Both cascadic multigrid methods do not need full elliptic regularity,so they can be used to tackle more general elliptic problems.Numerical experiments are reported to support our theory.展开更多
We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation ...We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation of electron interaction of correlated materials.Existing preconditioning techniques are not designed to be adaptive to varying numerical properties of the multi-length-scale systems.In this paper, we propose a hybrid incomplete Cholesky(HIC) preconditioner and demonstrate its adaptivity to the multi-length-scale systems.In addition,we propose an extension of the compressed sparse column with row access(CSCR) sparse matrix storage format to efficiently accommodate the data access pattern to compute the HIC preconditioner.We show that for moderately correlated materials,the HIC preconditioner achieves the optimal linear scaling of the simulation.The development of a linear-scaling preconditioner for strongly correlated materials remains an open topic.展开更多
As internet services newly emerge with diversity and complexity, great challenges and demands are presented to the Open Flow controlled software defined optical networks(SDON) to achieve better match between services ...As internet services newly emerge with diversity and complexity, great challenges and demands are presented to the Open Flow controlled software defined optical networks(SDON) to achieve better match between services and SDON. With this aim, this paper proposes a naive Echo-State-Network(Naive-ESN) based services awareness algorithm of the software defined optical network, where the naive ESN model adopts the ring topology structure and generates the probability output result to determine the Qo S policy of SDON. Moreover, the Naive-ESN engine is also designed in controller node of SDON to perform services awareness by obtaining service traffic features from data plan, together with some necessary extension of the Open Flow protocol. Test results show that the proposed approach is able to improved services-oriented supporting ability of SDON.展开更多
The conventional p-n heterojunction photocatalysts suffer from the incompatibility between the interfacial charge transfer efficiency and the redox ability of charge carriers.To optimize the interfacial charge transfe...The conventional p-n heterojunction photocatalysts suffer from the incompatibility between the interfacial charge transfer efficiency and the redox ability of charge carriers.To optimize the interfacial charge transfer of the conventional BiOI/TiO_(2) p-n photocatalyst,we synthesized the BiOI/Bi/TiO_(2) ternary photocatalyst with sandwiched metallic bismuth(Bi~0)by the oxygen-vacancy assisted method.The DFT calculation and structural characterizations confirmed the reaction of the electron-rich oxygen vacancies in the 2D-TiO_(2) nanosheets(TiO_(2)-NS)with the adsorbed BiO~+species.This reaction broke the Bi-O bonds to form Bi^(0) nanoparticles in-situ at the interface but still maintained the p-n heterojunction well.The NO-TPD and XRD analyses for samples correlated the Bi~0 formation with the oxygen vacancy concentrations well.The sandwiched Bi~0 functioned as an electronic transfer mediator like that in the Z-scheme heterostructure.Comparing with 0.20 BiOI/TiO_(2)-NP(NP,Nanoparticles),0.20 BiOI/Bi/TiO_(2)-NS-a(NS,Nanosheet)showed a much improved catalytic performance,i.e.,duplicated apparent quantum yield(AQY)and triplicated reaction rate constant(k).Also,the formation mechanism and the reaction mechanism were investigated in detail.This work provides a new strategy for the improving of the conventional p-n photocatalysts and new insights into the nature of the photocatalysis.展开更多
An oil-impregnated porous polyimide(PI)retainer is used in space rolling bearings to improve the lubrication performance,which depends on the release of lubricant from the pores,and therefore is closely related to the...An oil-impregnated porous polyimide(PI)retainer is used in space rolling bearings to improve the lubrication performance,which depends on the release of lubricant from the pores,and therefore is closely related to the pore size.To study the effect of pore size,in this work,PI materials with different pore sizes were prepared by preheating the retainer tube billet during the limit pressing process,and then the friction tests were conducted with the ball-on-ring mode.The results show that the applied load deforms the pores,allowing the lubricant to be squeezed out from the pore;the centrifugal effect induced by rotation also makes the lubricant migrate out of the pore.Therefore,for the same pore sizes,the friction coefficients decrease with the increasing loads and rotation speeds.In addition,it was found that there exists an optimal pore size for the best lubrication properties of porous PI material.Furthermore,the optimal pore size should be larger for lubricants with high viscosity.The microscopic mechanism for lubricant outflow from pores is clarified by molecular dynamic simulations.The insights gained in this study can guide the preparation of oil-impregnated porous retainers under different working conditions.展开更多
CO_(2) flooding can significantly improve the recovery rate, effectively recover crude oil, and has the advantages of energy saving and emission reduction. At present, most domestic researches on CO_(2) flooding seepa...CO_(2) flooding can significantly improve the recovery rate, effectively recover crude oil, and has the advantages of energy saving and emission reduction. At present, most domestic researches on CO_(2) flooding seepage experiments are field tests in actual reservoirs or simulations with reservoir numerical simulators. Although targeted, the promotion is poor. For the characterization of seepage resistance, there are few studies on the variation law of seepage resistance caused by the combined action in the reservoir. To solve this problem, based on the mechanism of CO_(2), a physical simulation experiment device for CO_(2) non-miscible flooding production manner is designed. The device adopts two displacement schemes, gas-displacing water and gas-displacing oil, it mainly studies the immiscible gas flooding mechanism and oil displacement characteristics based on factors such as formation dip angle, gas injection position, and gas injection rate. It can provide a more accurate development simulation for the actual field application. By studying the variation law of crude oil viscosity and start-up pressure gradient, the characterization method of seepage resistance gradient affected by these two factors in the seepage process is proposed. The field test is carried out for the natural core of the S oilfield, and the seepage resistance is described more accurately. The results show that the advancing front of the gas drive is an arc, and the advancing speed of the gas drive oil front is slower than that of gas drive water;the greater the dip angle, the higher the displacement efficiency;the higher the gas injection rate is, the higher the early recovery rate is, and the lower the later recovery rate is;oil displacement efficiency is lower than water displacement efficiency;taking the actual core of S oilfield as an example, the mathematical representation method of core start-up pressure gradient in low permeability reservoir is established.展开更多
CO_(2) immiscible flooding is an environmentally-friendly and effective method to enhance oil recovery in ultra-low permeability reservoirs.A mathematical model of CO_(2) immiscible flooding was developed,considering ...CO_(2) immiscible flooding is an environmentally-friendly and effective method to enhance oil recovery in ultra-low permeability reservoirs.A mathematical model of CO_(2) immiscible flooding was developed,considering the variation in crude oil viscosity and starting pressure gradient in ultra-low permeability reservoirs based on the non-Darcy percolation theory.The mathematical model and numerical simulator were developed in the C++language to simulate the effects of fluid viscosity,starting pressure gradient,and other physical parameters on the distribution of the oil pressure field,oil saturation field,gas saturation field,oil viscosity field,and oil production.The results showed that the formation pressure and pressure propagation velocity in CO_(2) immiscible flooding were lower than the findings without considering the starting pressure gradient.The formation oil content saturation and the crude oil formation viscosity were higher after the consideration of the starting pressure gradient.The viscosity of crude oil considering the initiation pressure gradient during the formation was higher than that without this gradient,but the yield was lower than that condition.Our novel mathematical models helped the characterization of seepage resistance,revealed the influence of fluid property changes on seepage,improved the mathematical model of oil seepage in immiscible flooding processes,and guided the improvement of crude oil recovery in immiscible flooding processes.展开更多
Owing to incurable castration-resistant prostate cancer(CRPC)ultimately developing after treating with androgen deprivation therapy(ADT),it is vital to devise new therapeutic strategies to treat CRPC.Treatments that t...Owing to incurable castration-resistant prostate cancer(CRPC)ultimately developing after treating with androgen deprivation therapy(ADT),it is vital to devise new therapeutic strategies to treat CRPC.Treatments that target programmed cell death protein 1(PD-1)and programmed death ligand-1(PD-L1)have been approved for human cancers with clinical benefit.However,many patients,especially prostate cancer,fail to respond to anti-PD-1/PD-L1 treatment,so it is an urgent need to seek a support strategy for improving the traditional PD-1/PD-L1 targeting immunotherapy.In the present study,analyzing the data from our prostate cancer tissue microarray,we found that PD-L1 expression was positively correlated with the expression of heterogeneous nuclear ribonucleoprotein L(Hn RNP L).Hence,we further investigated the potential role of Hn RNP L on the PD-L1 expression,the sensitivity of cancer cells to T-cell killing and the synergistic effect with anti-PD-1 therapy in CRPC.Indeed,Hn RNP L knockdown effectively decreased PD-L1 expression and recovered the sensitivity of cancer cells to T-cell killing in vitro and in vivo,on the contrary,Hn RNP L overexpression led to the opposite effect in CRPC cells.In addition,consistent with the previous study,we revealed that ferroptosis played a critical role in T-cell-induced cancer cell death,and Hn RNP L promoted the cancer immune escape partly through targeting YY1/PD-L1 axis and inhibiting ferroptosis in CRPC cells.Furthermore,Hn RNP L knockdown enhanced antitumor immunity by recruiting infiltrating CD8^(+)T cells and synergized with anti-PD-1 therapy in CRPC tumors.This study provided biological evidence that Hn RNP L knockdown might be a novel therapeutic agent in PD-L1/PD-1 blockade strategy that enhanced anti-tumor immune response in CRPC.展开更多
Background:COVID-19 has been impacting on the whole world critically and constantly since late December 2019.Rapidly increasing infections has raised intense worldwide attention.How to model the evolution of COVID-19 ...Background:COVID-19 has been impacting on the whole world critically and constantly since late December 2019.Rapidly increasing infections has raised intense worldwide attention.How to model the evolution of COVID-19 effectively and efficiently is of great significance for prevention and control.Methods:We propose the multi-chain Fudan-CCDC model based on the original single-chain model in[Shao et al.2020]to describe the evolution of COVID-19 in Singapore.Multi-chains can be considered as the superposition of several single chains with different characteristics.We identify the parameters of models by minimizing the penalty function.Results:The numerical simulation results exhibit the multi-chain model performs well on data fitting.Though unsteady the increments are,they could still fall within the range of±30%fluctuation from simulation results.Conclusion:The multi-chain Fudan-CCDC model provides an effective way to early detect the appearance of imported infectors and super spreaders and forecast a second outbreak.It can also explain the data from those countries where the single-chain model shows deviation from the data.展开更多
The onsite next generation sequencing(NGS)of Ebola virus(EBOV)genomes during the 2013–2016 Ebola epidemic in Western Africa provides an opportunity to trace the origin,transmission,and evolution of this virus.Herein,...The onsite next generation sequencing(NGS)of Ebola virus(EBOV)genomes during the 2013–2016 Ebola epidemic in Western Africa provides an opportunity to trace the origin,transmission,and evolution of this virus.Herein,we have diagnosed a cohort of EBOV patients in Sierra Leone in 2015,during the late phase of the outbreak.The surviving EBOV patients had a recovery process characterized by decreasing viremia,fever,and biochemical parameters.EBOV genomes sequenced through the longitudinal blood samples of these patients showed dynamic intra-host substitutions of the virus during acute infection,including the previously described short stretches of 13 serial TNC mutations.Remarkably,within individual patients,samples collected during the early phase of infection possessed Ts at these nucleotide sites,whereas they were replaced by Cs in samples collected in the later phase,suggesting that these short stretches of TNC mutations could emerge independently.In addition,up to a total of 35 nucleotide sites spanning the EBOV genome were mutated coincidently.Our study showed the dynamic intra-host adaptation of EBOV during patient recovery and gave more insight into the complex EBOV-host interactions.展开更多
The problem for determining the exchange rate function of 2D CCPF model by measurements on the partial boundary is considered and solved as one PDE-constraint optimization problem. The optimal variant is the minimum o...The problem for determining the exchange rate function of 2D CCPF model by measurements on the partial boundary is considered and solved as one PDE-constraint optimization problem. The optimal variant is the minimum of a cost functional that quantifies the difference between the measurements and the exact solutions. Gradientbased algorithm is used to solve this optimization problem. At each step, the derivative of the cost functional with respect to the exchange rate function is calculated and only one forward solution and one adjoint solution are needed. One method based on the adjoint equation is developed and implemented. Numerical examples show the efficiency of the adjoint method.展开更多
In this paper,numerical analysis is carried out for a class of history-dependent variationalhemivariational inequalities by arising in contact problems.Three different numerical treatments for temporal discretization ...In this paper,numerical analysis is carried out for a class of history-dependent variationalhemivariational inequalities by arising in contact problems.Three different numerical treatments for temporal discretization are proposed to approximate the continuous model.Fixed-point iteration algorithms are employed to implement the implicit scheme and the convergence is proved with a convergence rate independent of the time step-size and mesh grid-size.A special temporal discretization is introduced for the history-dependent operator,leading to numerical schemes for which the unique solvability and error bounds for the temporally discrete systems can be proved without any restriction on the time step-size.As for spatial approximation,the finite element method is applied and an optimal order error estimate for the linear element solutions is provided under appropriate regularity assumptions.Numerical examples are presented to illustrate the theoretical results.展开更多
This article concerns the weak Galerkin mixed finite element method(WGMFEM)for second order elliptic equations on 2D domains with curved boundary.The Neumann boundary condition is considered since it becomes the essen...This article concerns the weak Galerkin mixed finite element method(WGMFEM)for second order elliptic equations on 2D domains with curved boundary.The Neumann boundary condition is considered since it becomes the essential boundary condition in this case.It is well-known that the discrepancy between the curved physical domain and the polygonal approximation domain leads to a loss of accuracy for discretizationwith polynomial order a>1.The purpose of this paper is two-fold.First,we present a detailed error analysis of the original WG-MFEM for solving problems on curved domains,which exhibits an O(h^(1/2))convergence for all a≥1.It is a little surprising to see that even the lowest-order WG-MFEM(a=1)experiences a loss of accuracy.This is different from known results for the finite element method(FEM)or the mixed FEM,and appears to be a combined effect of the WG-MFEM design and the fact that the outward normal vector on the polygonal approximation domain is different from the one on the curved domain.Second,we propose a remedy to bring the approximation rate back to optimal by employing two techniques.One is a specially designed boundary correction technique.The other is to take full advantage of the nice feature that weak Galerkin discretization can be defined on polygonal meshes,which allows the curved boundary to be better approximated by multiple short edges without increasing the total number of mesh elements.Rigorous analysis shows that a combination of the above two techniques renders optimal convergence for all a.Numerical results further confirm this conclusion.展开更多
基金supported by the NationalNatural Science Foundation of China(No.61866023).
文摘Drone logistics is a novel method of distribution that will become prevalent.The advantageous location of the logistics hub enables quicker customer deliveries and lower fuel consumption,resulting in cost savings for the company’s transportation operations.Logistics firms must discern the ideal location for establishing a logistics hub,which is challenging due to the simplicity of existing models and the intricate delivery factors.To simulate the drone logistics environment,this study presents a new mathematical model.The model not only retains the aspects of the current models,but also considers the degree of transportation difficulty from the logistics hub to the village,the capacity of drones for transportation,and the distribution of logistics hub locations.Moreover,this paper proposes an improved particle swarm optimization(PSO)algorithm which is a diversity-based hybrid PSO(DHPSO)algorithm to solve this model.In DHPSO,the Gaussian random walk can enhance global search in the model space,while the bubble-net attacking strategy can speed convergence.Besides,Archimedes spiral strategy is employed to overcome the local optima trap in the model and improve the exploitation of the algorithm.DHPSO maintains a balance between exploration and exploitation while better defining the distribution of logistics hub locations Numerical experiments show that the newly proposed model always achieves better locations than the current model.Comparing DHPSO with other state-of-the-art intelligent algorithms,the efficiency of the scheme can be improved by 42.58%.This means that logistics companies can reduce distribution costs and consumers can enjoy a more enjoyable shopping experience by using DHPSO’s location selection.All the results show the location of the drone logistics hub is solved by DHPSO effectively.
基金the financial support from the National Natural Science Foundation of China(No.52074217)the Natural Science Basic Research Program of Shaanxi Province(No.2021JLM-26).
文摘The concept of the carbon cycle in the old goaf of a coal mine based on CO_(2)utilization and storage was put forward adhering to the principle of low-carbon development,utilization of space resources in old goafs,and associated gas resources development.Firstly,the evolution characteristics of overburden fissures in the goaf of the case was studied using a two-dimensional physical similarity simulation test,the sealing performance of the caprocks after stabilization was analyzed,and the fissures were counted and classi-fied.Then,the process of gaseous CO_(2)injection in the connected fissure was simulated by Ansys Fluent software,and the migration law and distribution characteristics of CO_(2)under the condition of gaseous CO_(2)injection were analyzed.Finally,the estimation models of free CO_(2)storage capacity in the old goaf were constructed considering the proportion of connected fissure and the effectiveness of CO_(2)injection.The CO_(2)storage capacity in the old goaf of the case coal mine was estimated.The results showed that a caprock group of“hard-thickness low-permeability hard-thickness”was formed after the caprock-fissures system in the goaf of the case tended to be stable vertically.The connected fissure,occlude cracks,and micro-fractures in the goaf accounted for 85.5%,8.5%,and 6%of the total fissures,respectively.Gaseous CO_(2)first migrated to the bottom of the connected fissure after CO_(2)was injected into the goaf,then spread horizontally along the bottom of the connected fissure after reaching the bottom,and finally spread longitudinally after filling the bottom of the entire connected fissure.The theoretical and effective storage capacities of free CO_(2)at normal temperature and pressure in the old goaf of the case were 9757 and 7477 t,respectively.The effective storage capacity of free CO_(2)at normal temperature and pressure in the old goaf after all minefield mined was 193404 t.The research can provide some reference for the coal mining industry to help the goal of“carbon peaking and carbon neutrality”.
基金supported by the National Natural Science Foundation of China(61975020,62171053)。
文摘Accurate traffic pattern prediction in largescale networks is of great importance for intelligent system management and automatic resource allocation.System-level mobile traffic forecasting has significant challenges due to the tremendous temporal and spatial dynamics introduced by diverse Internet user behaviors and frequent traffic migration.Spatialtemporal graph modeling is an efficient approach for analyzing the spatial relations and temporal trends of mobile traffic in a large system.Previous research may not reflect the optimal dependency by ignoring inter-base station dependency or pre-determining the explicit geological distance as the interrelationship of base stations.To overcome the limitations of graph structure,this study proposes an adaptive graph convolutional network(AGCN)that captures the latent spatial dependency by developing self-adaptive dependency matrices and acquires temporal dependency using recurrent neural networks.Evaluated on two mobile network datasets,the experimental results demonstrate that this method outperforms other baselines and reduces the mean absolute error by 3.7%and 5.6%compared to time-series based approaches.
文摘We report a case of a 74-year-old female with hypopharyngeal cancer who developed a pharyngoesophageal fistula and neck skin defect after total laryngectomy.To reconstruct the hypopharynx,upper esophagus,and neck skin defect,we used a supraclavicular artery island flap(SCAIF)for one-stage reconstruction.SCAIF offered reliable blood supply,minimal donor site morbidity,and excellent cosmetic outcomes.Although a small portion of the flap developed necrosis,it healed without surgical intervention.We also conducted a literature review of previously published articles on SCAIF for head and neck reconstruction.Our review highlights the advantages and limitations of SCAIF as a promising option for one-stage reconstruction of complex hypopharyngeal and upper esophageal defects with neck skin defects in selected patients.This case report provides valuable insights into the use of SCAIF in complex head and neck reconstructions,which can help improve patient outcomes and quality of life.
基金supported by the National Basic Research Program of China under the grant 2005CB321701the National Science Foundation(NSF) of China(10731060)111 project(B08018)
文摘In this paper,standard and economical cascadic multigrid methods are considered for solving the algebraic systems resulting from the mortar finite element methods. Both cascadic multigrid methods do not need full elliptic regularity,so they can be used to tackle more general elliptic problems.Numerical experiments are reported to support our theory.
基金supported in part by the US National Science Foundation grant 0611548in part by the US Department of Energy grant DE-FC02-06ER25793
文摘We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation of electron interaction of correlated materials.Existing preconditioning techniques are not designed to be adaptive to varying numerical properties of the multi-length-scale systems.In this paper, we propose a hybrid incomplete Cholesky(HIC) preconditioner and demonstrate its adaptivity to the multi-length-scale systems.In addition,we propose an extension of the compressed sparse column with row access(CSCR) sparse matrix storage format to efficiently accommodate the data access pattern to compute the HIC preconditioner.We show that for moderately correlated materials,the HIC preconditioner achieves the optimal linear scaling of the simulation.The development of a linear-scaling preconditioner for strongly correlated materials remains an open topic.
基金supported by the Science and Technology Project of State Grid Corporation of China:“Research on the Power-Grid Services Oriented “IP+Optical” Coordination Choreography Technology”.
文摘As internet services newly emerge with diversity and complexity, great challenges and demands are presented to the Open Flow controlled software defined optical networks(SDON) to achieve better match between services and SDON. With this aim, this paper proposes a naive Echo-State-Network(Naive-ESN) based services awareness algorithm of the software defined optical network, where the naive ESN model adopts the ring topology structure and generates the probability output result to determine the Qo S policy of SDON. Moreover, the Naive-ESN engine is also designed in controller node of SDON to perform services awareness by obtaining service traffic features from data plan, together with some necessary extension of the Open Flow protocol. Test results show that the proposed approach is able to improved services-oriented supporting ability of SDON.
基金financially supported by the National Natural Science Foundation of China(No.21043006 and 51702205)the Education Department of Guangdong Province(No.2018KTSCX063 and 2013KJCX0081)+2 种基金the Science and Technology Planning Project of Guangdong Province(No.2014A020216045)the 2020 Li Ka Shing Foundation Cross-Disciplinary Research Grant(2020LKSFG09A)the Guangdong Key Discipline Fund at GTIIT。
文摘The conventional p-n heterojunction photocatalysts suffer from the incompatibility between the interfacial charge transfer efficiency and the redox ability of charge carriers.To optimize the interfacial charge transfer of the conventional BiOI/TiO_(2) p-n photocatalyst,we synthesized the BiOI/Bi/TiO_(2) ternary photocatalyst with sandwiched metallic bismuth(Bi~0)by the oxygen-vacancy assisted method.The DFT calculation and structural characterizations confirmed the reaction of the electron-rich oxygen vacancies in the 2D-TiO_(2) nanosheets(TiO_(2)-NS)with the adsorbed BiO~+species.This reaction broke the Bi-O bonds to form Bi^(0) nanoparticles in-situ at the interface but still maintained the p-n heterojunction well.The NO-TPD and XRD analyses for samples correlated the Bi~0 formation with the oxygen vacancy concentrations well.The sandwiched Bi~0 functioned as an electronic transfer mediator like that in the Z-scheme heterostructure.Comparing with 0.20 BiOI/TiO_(2)-NP(NP,Nanoparticles),0.20 BiOI/Bi/TiO_(2)-NS-a(NS,Nanosheet)showed a much improved catalytic performance,i.e.,duplicated apparent quantum yield(AQY)and triplicated reaction rate constant(k).Also,the formation mechanism and the reaction mechanism were investigated in detail.This work provides a new strategy for the improving of the conventional p-n photocatalysts and new insights into the nature of the photocatalysis.
基金This work was supported by the National Natural Science Foundation of China(U2141243 and 52175158).
文摘An oil-impregnated porous polyimide(PI)retainer is used in space rolling bearings to improve the lubrication performance,which depends on the release of lubricant from the pores,and therefore is closely related to the pore size.To study the effect of pore size,in this work,PI materials with different pore sizes were prepared by preheating the retainer tube billet during the limit pressing process,and then the friction tests were conducted with the ball-on-ring mode.The results show that the applied load deforms the pores,allowing the lubricant to be squeezed out from the pore;the centrifugal effect induced by rotation also makes the lubricant migrate out of the pore.Therefore,for the same pore sizes,the friction coefficients decrease with the increasing loads and rotation speeds.In addition,it was found that there exists an optimal pore size for the best lubrication properties of porous PI material.Furthermore,the optimal pore size should be larger for lubricants with high viscosity.The microscopic mechanism for lubricant outflow from pores is clarified by molecular dynamic simulations.The insights gained in this study can guide the preparation of oil-impregnated porous retainers under different working conditions.
基金the Dongying Science Development Fund Project(Nos.DJ2022009 and DJ2020003)the Shandong Provincial Higher Education Research and Development Program(Science and Technology A Class)(No.J18KA201)+2 种基金the High-level Talent Research Start-up Fund of Shengli College of China University of Petroleum(No.KQ2019-008)the Chunhui Project of Shengli College of China University of Petroleum(No.KY2017004)the Research Cultivation Project of College of Big Data and Basic Science of Shandong Institute of Petroleum and Chemical Technology(No.XYPY2201)which supports are appreciated.
文摘CO_(2) flooding can significantly improve the recovery rate, effectively recover crude oil, and has the advantages of energy saving and emission reduction. At present, most domestic researches on CO_(2) flooding seepage experiments are field tests in actual reservoirs or simulations with reservoir numerical simulators. Although targeted, the promotion is poor. For the characterization of seepage resistance, there are few studies on the variation law of seepage resistance caused by the combined action in the reservoir. To solve this problem, based on the mechanism of CO_(2), a physical simulation experiment device for CO_(2) non-miscible flooding production manner is designed. The device adopts two displacement schemes, gas-displacing water and gas-displacing oil, it mainly studies the immiscible gas flooding mechanism and oil displacement characteristics based on factors such as formation dip angle, gas injection position, and gas injection rate. It can provide a more accurate development simulation for the actual field application. By studying the variation law of crude oil viscosity and start-up pressure gradient, the characterization method of seepage resistance gradient affected by these two factors in the seepage process is proposed. The field test is carried out for the natural core of the S oilfield, and the seepage resistance is described more accurately. The results show that the advancing front of the gas drive is an arc, and the advancing speed of the gas drive oil front is slower than that of gas drive water;the greater the dip angle, the higher the displacement efficiency;the higher the gas injection rate is, the higher the early recovery rate is, and the lower the later recovery rate is;oil displacement efficiency is lower than water displacement efficiency;taking the actual core of S oilfield as an example, the mathematical representation method of core start-up pressure gradient in low permeability reservoir is established.
基金the Dongying Science Development Fund Project(Nos.DJ2022009 and DJ2020003)the Shandong Provincial Higher Education Research and Development Program(Science and Technology A Class)(No.J18KA201)+2 种基金the High-level Talent Research Start-up Fund of Shengli College of China University of Petroleum(No.KQ2019-008)the Chunhui Project of Shengli College of China University of Petroleum(No.KY2017004)the Research Cultivation Project of College of Big Data and Basic Science of Shandong Institute of Petroleum and Chemical Technology(No.XYPY2201)which supports are appreciated.
文摘CO_(2) immiscible flooding is an environmentally-friendly and effective method to enhance oil recovery in ultra-low permeability reservoirs.A mathematical model of CO_(2) immiscible flooding was developed,considering the variation in crude oil viscosity and starting pressure gradient in ultra-low permeability reservoirs based on the non-Darcy percolation theory.The mathematical model and numerical simulator were developed in the C++language to simulate the effects of fluid viscosity,starting pressure gradient,and other physical parameters on the distribution of the oil pressure field,oil saturation field,gas saturation field,oil viscosity field,and oil production.The results showed that the formation pressure and pressure propagation velocity in CO_(2) immiscible flooding were lower than the findings without considering the starting pressure gradient.The formation oil content saturation and the crude oil formation viscosity were higher after the consideration of the starting pressure gradient.The viscosity of crude oil considering the initiation pressure gradient during the formation was higher than that without this gradient,but the yield was lower than that condition.Our novel mathematical models helped the characterization of seepage resistance,revealed the influence of fluid property changes on seepage,improved the mathematical model of oil seepage in immiscible flooding processes,and guided the improvement of crude oil recovery in immiscible flooding processes.
基金supported by the National Natural Science Foundation of China(Grant No.81773277)Science and Technology Program of Guangzhou,China(Grant No.201803010014)+3 种基金Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2020A1515110922 and 2019A1515110033,China)China Postdoctoral Science Foundation funded project(Grant Nos.2018M643126 and 2019M662865)Distinguished Young Talents in Higher Education Foundation of Guangdong Province(Grant No.2019KQNCX115,China)Achievement Cultivation and Clinical Transformation Application Cultivation Projects of the First Affiliated Hospital of Guangzhou Medical University(Grant No.ZH201908,China)。
文摘Owing to incurable castration-resistant prostate cancer(CRPC)ultimately developing after treating with androgen deprivation therapy(ADT),it is vital to devise new therapeutic strategies to treat CRPC.Treatments that target programmed cell death protein 1(PD-1)and programmed death ligand-1(PD-L1)have been approved for human cancers with clinical benefit.However,many patients,especially prostate cancer,fail to respond to anti-PD-1/PD-L1 treatment,so it is an urgent need to seek a support strategy for improving the traditional PD-1/PD-L1 targeting immunotherapy.In the present study,analyzing the data from our prostate cancer tissue microarray,we found that PD-L1 expression was positively correlated with the expression of heterogeneous nuclear ribonucleoprotein L(Hn RNP L).Hence,we further investigated the potential role of Hn RNP L on the PD-L1 expression,the sensitivity of cancer cells to T-cell killing and the synergistic effect with anti-PD-1 therapy in CRPC.Indeed,Hn RNP L knockdown effectively decreased PD-L1 expression and recovered the sensitivity of cancer cells to T-cell killing in vitro and in vivo,on the contrary,Hn RNP L overexpression led to the opposite effect in CRPC cells.In addition,consistent with the previous study,we revealed that ferroptosis played a critical role in T-cell-induced cancer cell death,and Hn RNP L promoted the cancer immune escape partly through targeting YY1/PD-L1 axis and inhibiting ferroptosis in CRPC cells.Furthermore,Hn RNP L knockdown enhanced antitumor immunity by recruiting infiltrating CD8^(+)T cells and synergized with anti-PD-1 therapy in CRPC tumors.This study provided biological evidence that Hn RNP L knockdown might be a novel therapeutic agent in PD-L1/PD-1 blockade strategy that enhanced anti-tumor immune response in CRPC.
基金the National Natural Science Foundation of China(No.11671098)partially supported by Shanghai Science and technology research program(No.19JC1420101)+1 种基金J.C.is supported in part by the National Natural Science Foundation of China(No.11971121)Y.Y.is supported by Shanghai Sailing Program(No.20YF1412400).
文摘Background:COVID-19 has been impacting on the whole world critically and constantly since late December 2019.Rapidly increasing infections has raised intense worldwide attention.How to model the evolution of COVID-19 effectively and efficiently is of great significance for prevention and control.Methods:We propose the multi-chain Fudan-CCDC model based on the original single-chain model in[Shao et al.2020]to describe the evolution of COVID-19 in Singapore.Multi-chains can be considered as the superposition of several single chains with different characteristics.We identify the parameters of models by minimizing the penalty function.Results:The numerical simulation results exhibit the multi-chain model performs well on data fitting.Though unsteady the increments are,they could still fall within the range of±30%fluctuation from simulation results.Conclusion:The multi-chain Fudan-CCDC model provides an effective way to early detect the appearance of imported infectors and super spreaders and forecast a second outbreak.It can also explain the data from those countries where the single-chain model shows deviation from the data.
基金supported by the Megaproject for Infectious Disease Research of China(2016ZX10004222-003)the research of Ebola pathogen from the National Natural Science Foundation of China(NSFC,81590763)+4 种基金National Key Research and Development Program of China(2016YFC1200200 to Y.Shu)the Distinguished Young Scientist Program of the NSFC(81525017 to Y.Shu)the Excellent Young Scientist Program of the NSFC(81822040 to W.J.Liu)the Taishan Scholar Project of Shandong Province(ts201511056 to W.Shi)G.F.Gao is a primary principal investigator of the NSFC Innovative Research Group(81621091).
文摘The onsite next generation sequencing(NGS)of Ebola virus(EBOV)genomes during the 2013–2016 Ebola epidemic in Western Africa provides an opportunity to trace the origin,transmission,and evolution of this virus.Herein,we have diagnosed a cohort of EBOV patients in Sierra Leone in 2015,during the late phase of the outbreak.The surviving EBOV patients had a recovery process characterized by decreasing viremia,fever,and biochemical parameters.EBOV genomes sequenced through the longitudinal blood samples of these patients showed dynamic intra-host substitutions of the virus during acute infection,including the previously described short stretches of 13 serial TNC mutations.Remarkably,within individual patients,samples collected during the early phase of infection possessed Ts at these nucleotide sites,whereas they were replaced by Cs in samples collected in the later phase,suggesting that these short stretches of TNC mutations could emerge independently.In addition,up to a total of 35 nucleotide sites spanning the EBOV genome were mutated coincidently.Our study showed the dynamic intra-host adaptation of EBOV during patient recovery and gave more insight into the complex EBOV-host interactions.
基金supported by the Key Project National Science Foundation of China(No.91130004)the Natural Science Foundation of China(Nos.11171077,11331004)the National Talents Training Base for Basic Research and Teaching of Natural Science of China(No.J1103105)
文摘The problem for determining the exchange rate function of 2D CCPF model by measurements on the partial boundary is considered and solved as one PDE-constraint optimization problem. The optimal variant is the minimum of a cost functional that quantifies the difference between the measurements and the exact solutions. Gradientbased algorithm is used to solve this optimization problem. At each step, the derivative of the cost functional with respect to the exchange rate function is calculated and only one forward solution and one adjoint solution are needed. One method based on the adjoint equation is developed and implemented. Numerical examples show the efficiency of the adjoint method.
基金supported by National Natural Science Foundation of China(Grant Nos.11671098 and 91630309)Higher Education Discipline Innovation Project(111 Project)(Grant No.B08018)Institute of Scientific Computation and Financial Data Analysis,Shanghai University of Finance and Economics for the support during his visit。
文摘In this paper,numerical analysis is carried out for a class of history-dependent variationalhemivariational inequalities by arising in contact problems.Three different numerical treatments for temporal discretization are proposed to approximate the continuous model.Fixed-point iteration algorithms are employed to implement the implicit scheme and the convergence is proved with a convergence rate independent of the time step-size and mesh grid-size.A special temporal discretization is introduced for the history-dependent operator,leading to numerical schemes for which the unique solvability and error bounds for the temporally discrete systems can be proved without any restriction on the time step-size.As for spatial approximation,the finite element method is applied and an optimal order error estimate for the linear element solutions is provided under appropriate regularity assumptions.Numerical examples are presented to illustrate the theoretical results.
基金supported by Postgraduate Research&Practice Innovation Program of Jiangsu Province 1812000024768supported by the NSFC grant 12171244.Chen is supported by NSFC grant 12071090.
文摘This article concerns the weak Galerkin mixed finite element method(WGMFEM)for second order elliptic equations on 2D domains with curved boundary.The Neumann boundary condition is considered since it becomes the essential boundary condition in this case.It is well-known that the discrepancy between the curved physical domain and the polygonal approximation domain leads to a loss of accuracy for discretizationwith polynomial order a>1.The purpose of this paper is two-fold.First,we present a detailed error analysis of the original WG-MFEM for solving problems on curved domains,which exhibits an O(h^(1/2))convergence for all a≥1.It is a little surprising to see that even the lowest-order WG-MFEM(a=1)experiences a loss of accuracy.This is different from known results for the finite element method(FEM)or the mixed FEM,and appears to be a combined effect of the WG-MFEM design and the fact that the outward normal vector on the polygonal approximation domain is different from the one on the curved domain.Second,we propose a remedy to bring the approximation rate back to optimal by employing two techniques.One is a specially designed boundary correction technique.The other is to take full advantage of the nice feature that weak Galerkin discretization can be defined on polygonal meshes,which allows the curved boundary to be better approximated by multiple short edges without increasing the total number of mesh elements.Rigorous analysis shows that a combination of the above two techniques renders optimal convergence for all a.Numerical results further confirm this conclusion.
