Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial ac...Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial activation and neuroinflammation, edema, ischemia, vascular injury, energy failure, and peripheral immune cell infiltration. The timing of these events post injury has been linked to injury severity and functional outcome. Extracellular vesicles are membrane bound secretory vesicles that contain markers and cargo pertaining to their cell of origin and can cross the blood-brain barrier. These qualities make extracellular vesicles intriguing candidates for a liquid biopsy into the pathophysiologic changes occurring at the cellular level post traumatic brain injury. Herein, we review the most commonly reported cargo changes in extracellular vesicles from clinical traumatic brain injury samples. We then use knowledge from animal and in vitro models to help infer what these changes may indicate regrading cellular responses post traumatic brain injury. Future research should prioritize labeling extracellular vesicles with markers for distinct cell types across a range of timepoints post traumatic brain injury.展开更多
The objective of reliability-based design optimization(RBDO)is to minimize the optimization objective while satisfying the corresponding reliability requirements.However,the nested loop characteristic reduces the effi...The objective of reliability-based design optimization(RBDO)is to minimize the optimization objective while satisfying the corresponding reliability requirements.However,the nested loop characteristic reduces the efficiency of RBDO algorithm,which hinders their application to high-dimensional engineering problems.To address these issues,this paper proposes an efficient decoupled RBDO method combining high dimensional model representation(HDMR)and the weight-point estimation method(WPEM).First,we decouple the RBDO model using HDMR and WPEM.Second,Lagrange interpolation is used to approximate a univariate function.Finally,based on the results of the first two steps,the original nested loop reliability optimization model is completely transformed into a deterministic design optimization model that can be solved by a series of mature constrained optimization methods without any additional calculations.Two numerical examples of a planar 10-bar structure and an aviation hydraulic piping system with 28 design variables are analyzed to illustrate the performance and practicability of the proposed method.展开更多
Ammonia detection possesses great potential in atmosphere environmental protection,agriculture,industry,and rapid medical diagnosis.However,it still remains a great challenge to balance the sensitivity,selectivity,wor...Ammonia detection possesses great potential in atmosphere environmental protection,agriculture,industry,and rapid medical diagnosis.However,it still remains a great challenge to balance the sensitivity,selectivity,working temperature,and response/recovery speed.In this work,Berlin green(BG)framework is demonstrated as a highly promising sensing material for ammonia detection by both density functional theory simulation and experimental gas sensing investigation.Vacancy in BG framework offers abundant active sites for ammonia absorption,and the absorbed ammonia transfers sufficient electron to BG,arousing remarkable enhancement of resistance.Pristine BG framework shows remarkable response to ammonia at 50–110°C with the highest response at 80°C,which is jointly influenced by ammonia’s absorption onto BG surface and insertion into BG lattice.The sensing performance of BG can hardly be achieved at room temperature due to its high resistance.Introduction of conductive Ti3CN MXene overcomes the high resistance of pure BG framework,and the simply prepared BG/Ti3CN mixture shows high selectivity to ammonia at room temperature with satisfying response/recovery speed.展开更多
The importance analysis method represents a powerful tool for quantifying the impact of input uncertainty on the output uncertainty.When an input variable is described by a specific interval rather than a certain prob...The importance analysis method represents a powerful tool for quantifying the impact of input uncertainty on the output uncertainty.When an input variable is described by a specific interval rather than a certain probability distribution,the interval importance measure of input interval variable can be calculated by the traditional non-probabilistic importance analysis methods.Generally,the non-probabilistic importance analysis methods involve the Monte Carlo simulation(MCS)and the optimization-based methods,which both have high computational cost.In order to overcome this problem,this study proposes an interval important analytical method avoids the time-consuming optimization process.First,the original performance function is decomposed into a combination of a series of one-dimensional subsystems.Next,the interval of each variable is divided into several subintervals,and the response value of each one-dimensional subsystem at a specific input point is calculated.Then,the obtained responses are taken as specific values of the new input variable,and the interval importance is calculated by the approximated performance function.Compared with the traditional non-probabilistic importance analysis method,the proposed method significantly reduces the computational cost caused by the MCS and optimization process.In the proposed method,the number of function evaluations is equal to one plus the sum of the subintervals of all of the variables.The efficiency and accuracy of the proposed method are verified by five examples.The results show that the proposed method is not only efficient but also accurate.展开更多
Natural photosynthesis,which provides a green and high-efficiency energy conversion path by spatial separation of photogenerated carriers through combined actions of molecules ingeniously arranged in an efficient sola...Natural photosynthesis,which provides a green and high-efficiency energy conversion path by spatial separation of photogenerated carriers through combined actions of molecules ingeniously arranged in an efficient solar nanospace,highlights the importance of rational nanostructure design to realize artificial high-efficiency photosystem.Inspired by these unique features,we constructed a high-efficiency ternary photosystem by selectively decorating the{001}facets of 18-facet SrTiO_(3)with Au@CdS photosensitizers via a green photo-assisted method.Benefiting from the dual-facilitated charge carriers transportation in core-shell structured Au@CdS heterojunction and well-faceted 18-facet SrTiO_(3)nanocrystal,such a photo-catalyst could realize the effective spatial separation of photogenerated electrons and holes.As expected,the 18-facet SrTiO_(3)/Au@CdS photocatalyst exhibits superior activity in visible-light-driven photocatalytic hydrogen evolution(4.61 mmol h^(−1)g^(−1)),166%improvement in comparison with randomly deposited Au@CdS(1.73 mmol h^(−1)g^(−1)).This work offers new insight into the development of green and high-efficiency photocatalytic systems based on the rational nanostructure design by crystal facet engineering.展开更多
This paper considered a multi-stage sheep brucellosis model with incomplete immunity.First,we established a deterministic model,calculated the basic reproduction number R_(0),set out the conditions for the global stab...This paper considered a multi-stage sheep brucellosis model with incomplete immunity.First,we established a deterministic model,calculated the basic reproduction number R_(0),set out the conditions for the global stability of the disease-free equilibrium and endemic equilibrium.Second,considering the influence of environmental white noise on brucellosis infection,we further established the stochastic version of the model.By constructing a suitable Lyapunov function,we proved the existence and uniqueness of the global positive solution.Further,we got the sufficient conditions for disease extinction and the existence of ergodic stationary distribution.Finally,we carried out some numerical simulations to verify the theoretical results.展开更多
Lead-free(K_(0.5)Na_(0.5))NbO_(3)(KNN)and Li_(0.06)(K_(0.5)Na_(0.5))_(0.94)NbO_(3)(LKNN)thin films were fabricated by a sol-gel method.The effects of Li substitution on crystal structure,microstructure and electrical ...Lead-free(K_(0.5)Na_(0.5))NbO_(3)(KNN)and Li_(0.06)(K_(0.5)Na_(0.5))_(0.94)NbO_(3)(LKNN)thin films were fabricated by a sol-gel method.The effects of Li substitution on crystal structure,microstructure and electrical properties of KNN film were systematically studied.Li doping can enhance the ferroelectric and piezoelectric properties of KNN film.Compared with pure KNN film,the LKNN film possesses larger remanent polarization(P_(r)~9.3μC/cm^(2))and saturated polarization(P_(s)~41.2μC/cm^(2))and lower leakage current density(~10^(−5)A/cm^(2)at 200 kV/cm).Meanwhile,a typical butterfly shaped piezoelectric response curve is obtained in the LKNN film with a high piezoelectric coefficient(d_(33)~105 pm/V).Excellent fatigue resistance(~10^(9)switching cycles)and aging resistance(~180 days)demonstrate the long-term working stability of LKNN film.These findings indicate that KNN-based lead-free piezoelectric films have a broad application prospect in microelectromechanical systems(MEMS).展开更多
Solving optimal control problems serves as the basic demand of industrial control tasks.Existing methods like model predictive control often suffer from heavy online computational burdens.Reinforcement learning has sh...Solving optimal control problems serves as the basic demand of industrial control tasks.Existing methods like model predictive control often suffer from heavy online computational burdens.Reinforcement learning has shown promise in computer and board games but has yet to be widely adopted in industrial applications due to a lack of accessible,high-accuracy solvers.Current Reinforcement learning(RL)solvers are often developed for academic research and require a significant amount of theoretical knowledge and programming skills.Besides,many of them only support Python-based environments and limit to model-free algorithms.To address this gap,this paper develops General Optimal control Problems Solver(GOPS),an easy-to-use RL solver package that aims to build real-time and high-performance controllers in industrial fields.GOPS is built with a highly modular structure that retains a flexible framework for secondary development.Considering the diversity of industrial control tasks,GOPS also includes a conversion tool that allows for the use of Matlab/Simulink to support environment construction,controller design,and performance validation.To handle large-scale problems,GOPS can automatically create various serial and parallel trainers by flexibly combining embedded buffers and samplers.It offers a variety of common approximate functions for policy and value functions,including polynomial,multilayer perceptron,convolutional neural network,etc.Additionally,constrained and robust algorithms for special industrial control systems with state constraints and model uncertainties are also integrated into GOPS.Several examples,including linear quadratic control,inverted double pendulum,vehicle tracking,humanoid robot,obstacle avoidance,and active suspension control,are tested to verify the performances of GOPS.展开更多
近些年,我国成功开发了以煤为原料的甲醇制烯烃(Methanol to Olefins,MTO)生产工艺和技术,带动煤制烯烃产业的快速发展,保障了国家能源安全。流化床式反应器是MTO工业生产的核心反应装置,通过计算流体力学(Computational Fluid Dynamics...近些年,我国成功开发了以煤为原料的甲醇制烯烃(Methanol to Olefins,MTO)生产工艺和技术,带动煤制烯烃产业的快速发展,保障了国家能源安全。流化床式反应器是MTO工业生产的核心反应装置,通过计算流体力学(Computational Fluid Dynamics,CFD)方法深入认知MTO流化床内的流化特性规律具有重要的意义,它可以从理论上更加准确地指导MTO流化床的优化与放大。本工作采用基于宏观-亚网格层次的气泡EMMS曳力和传统TFM耦合计算的多尺度CFD方法,对工业尺度MTO流化床内的多相流化行为进行了三维数值模拟。模拟结果表明,该多尺度CFD方法考虑了气泡结构对气-固相间曳力的影响,能较准确地预测MTO流化床内轴向颗粒浓度的"S-型"分布规律,且得到实验数据的验证;所预测的径向颗粒浓度分布呈现出经典的"环-核"分布规律,气体/颗粒的轴向时均速度在径向上的分布也与实际情况相互佐证,表明该多尺度CFD方法显著改善了基于均匀曳力的传统TFM对于宏观流场的预测能力。下一步工作将多尺度CFD方法拓展应用于MTO流化床优化放大及反应特性的研究。展开更多
In an uncertainty scheme, reliability and global sensitivity analysis is studied in this work, to provide helpful information for probabilistic anti-resonance design of vibration systems.Discussions show that the reso...In an uncertainty scheme, reliability and global sensitivity analysis is studied in this work, to provide helpful information for probabilistic anti-resonance design of vibration systems.Discussions show that the resonance failure problem can be viewed as a series system, in which input uncertainties are modeled by random variables. In order to quantitatively measure the contributions of input variables to the system reliability, a global sensitivity index is proposed, the properties of which are also discussed. Then the proposed index is tested with an aeronautical hydraulic pipeline system, which is under the excitation of pump vibration and at a risk of resonance failure. Sensitivity results under different failure criteria and variation coefficients are obtained and studied, from which significant and insignificant input variables can be identified.The proposed method provides a relatively new insight for anti-resonance design of engineering structures.展开更多
Traditional Global Sensitivity Analysis(GSA) focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is...Traditional Global Sensitivity Analysis(GSA) focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is beyond the traditional GSA techniques.To fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function(RIMPDF) and Regional Importance Measure based on Cumulative Distribution Function(RIMCDF),are introduced to find out the contributions of specific regions of an input to the whole output distribution.The two regional importance measures prove to be reasonable supplements of the traditional GSA techniques.The ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.展开更多
The impacts of petroleum contamination on the litter decomposition of shrub–grass land would directly influence nutrient cycling, and the stability and function of ecosystem. Ten common shrub and grass species from Y...The impacts of petroleum contamination on the litter decomposition of shrub–grass land would directly influence nutrient cycling, and the stability and function of ecosystem. Ten common shrub and grass species from Yujiaping oil deposits were studied. Litters from these species were placed into litterbags and buried in petroleum-contaminated soil with 3levels of contamination(slight, moderate and serious pollution with petroleum concentrations of 15, 30 and 45 g/kg, respectively). A decomposition experiment was then conducted in the lab to investigate the impacts of petroleum contamination on litter decomposition rates. Slight pollution did not inhibit the decomposition of any litters and significantly promoted the litter decomposition of Hippophae rhamnoides, Caragana korshinskii, Amorpha fruticosa, Ziziphus jujuba var. spinosa, Periploca sepium, Medicago sativa and Bothriochloa ischaemum. Moderate pollution significantly inhibited litter decomposition of M. sativa,Coronilla varia, Artemisia vestita and Trrifolium repens and significantly promoted the litter decomposition of C. korshinskii, Z. jujuba var. spinosa and P. sepium. Serious pollution significantly inhibited the litter decomposition of H. rhamnoides, A. fruticosa, B. ischaemum and A. vestita and significantly promoted the litter decomposition of Z. jujuba var. spinosa, P.sepium and M. sativa. In addition, the impacts of petroleum contamination did not exhibit a uniform increase or decrease as petroleum concentration increased. Inhibitory effects of petroleum on litter decomposition may hinder the substance cycling and result in the degradation of plant communities in contaminated areas.展开更多
As one of the most delicate bioprocesses in nature,biosilicification is closely related to biosilica with various morphologies,and has provided abundant inspiration to materials synthesis.In the present study,to explo...As one of the most delicate bioprocesses in nature,biosilicification is closely related to biosilica with various morphologies,and has provided abundant inspiration to materials synthesis.In the present study,to explore the biosilica formation process and fabricate silica with an exquisite microstructure for lithiumion battery(LIB)electrodes,a bacterial phage(M13)is used as a biotemplate to synthesize silica with diverse morphologies:cylinders,hexagonal prisms,assemblies of smaller cylinders and nanowires.A facile ethanol bath method is conducted to coat the nanowires with nitrogen-containing carbon and carbon-coated SiO_(2) nanowires with mesochannels(C@msSiO_(2) NWs)are first used as anode materials for LIBs.Attributed to the uniform carbon coating and parallel mesochannel structure,the electronic conductivity and capacity to accommodate volume variations were significantly improved.In the electrochemical perfo rmance test,the composites calcined at 750℃(C@msSiO_(2) NWs-750)show an impressive capacity of 653 mA h g^(-1) at a current density of 500 mA g^(-1) and stability(1000 cycles).In view of the electrochemical test outcomes,the prepa ration of a sophisticated structure with an outstanding potential is easily achieved via a biomimetic strategy.展开更多
In this work,we present a versatile surface engineering strategy by the combination of mussel adhesive peptide mimicking and bioorthogonal click chemistry.The main idea reflected in this work derived from a novel muss...In this work,we present a versatile surface engineering strategy by the combination of mussel adhesive peptide mimicking and bioorthogonal click chemistry.The main idea reflected in this work derived from a novel mussel-inspired peptide mimic with a bioclickable azide group(i.e.,DOPA_(4)-azide).Similar to the adhesion mechanism of the mussel foot protein(i.e.,covalent/noncovalent comediated surface adhesion),the bioinspired and bioclickable peptide mimic DOPA_(4)-azide enables stable binding on a broad range of materials,such as metallic,inorganic,and organic polymer substrates.In addition to the material universality,the azide residues of DOPA_(4)-azide are also capable of a specific conjugation of dibenzylcyclooctyne-(DBCO-)modified bioactive ligands through bioorthogonal click reaction in a second step.To demonstrate the applicability of this strategy for diversified biofunctionalization,we bioorthogonally conjugated several typical bioactive molecules with DBCO functionalization on different substrates to fabricate functional surfaces which fulfil essential requirements of biomedically used implants.For instance,antibiofouling,antibacterial,and antithrombogenic properties could be easily applied to the relevant biomaterial surfaces,by grafting antifouling polymer,antibacterial peptide,and NO-generating catalyst,respectively.Overall,the novel surface bioengineering strategy has shown broad applicability for both the types of substrate materials and the expected biofunctionalities.Conceivably,the“clean”molecular modification of bioorthogonal chemistry and the universality of mussel-inspired surface adhesion may synergically provide a versatile surface bioengineering strategy for a wide range of biomedical materials.展开更多
Cancer is a serious threat to humans due to its high mortality. The efforts to fully understand cancer and to fight against it have never been stopped. The traditional therapies, such as surgery, radiotherapy and chem...Cancer is a serious threat to humans due to its high mortality. The efforts to fully understand cancer and to fight against it have never been stopped. The traditional therapies, such as surgery, radiotherapy and chemotherapy, are useful but cannot meet the increasing demands of patients. As such, novel approaches against cancer are urgently required. It has been found that the acidic tumor microenvironment plays important roles in promoting the cancer progression. In recent years, sodium bicarbonate(NaHCO_(3)), a simple inorganic salt, has been found to be able to reverse the p H of tumor microenvironment and inhibit the invasion, metastasis, immune evasion, drug resistance and hypoxia of tumor cells. Thus, NaHCO_(3)-based therapy is a potential approach for the treatment of cancer, and the related studies have been increasingly reported. Herein, we aim to provide a comprehensive understanding of the acidic tumor microenvironment and summarize the applications and mechanisms of Na HCO_(3)in cancer therapy. The combination of Na HCO;with chemotherapy, immunotherapy or nanoparticles systems is discussed. In addition, the concerns of Na HCO_(3)in clinical use and the potential ways to use Na HCO_(3)for cancer therapy are also discussed.展开更多
The BiFeO3-based film is one of the most promising candidates for lead-free piezoelectric film devices.In this work,the 1μm-thick Bi(Fe_(0.93)Mn_(0.05)Ti_(0.02))O_(3)(BFMT)films are grown on the ITO/glass substrate u...The BiFeO3-based film is one of the most promising candidates for lead-free piezoelectric film devices.In this work,the 1μm-thick Bi(Fe_(0.93)Mn_(0.05)Ti_(0.02))O_(3)(BFMT)films are grown on the ITO/glass substrate using a sol-gel method combined with spin-coating and layer-by-layer annealing technique.These films display a large saturated polarization of 95μC/cm^(2),and a remanent polarization of 70μC/cm^(2).Especially,the films are self-poled caused by an internal bias field,giving rise to asymmetric polarization-electric field(P-E)loops with a positive shift along the x-axis.A stable self-polarization state is maintained during the applied electric field increasing to 1500 kV/cm and then decreasing back.The weak dependence of P-E loops on frequency(1-50 kHz)and temperature(25-125°C)indicate that the internal bias field can be stable within a certain frequency and temperature range.These results demonstrate that the self-polarized BFMT thick films can be integrated into devices without any poling process,with promising applications in micro-electro-mechanical systems.展开更多
BiScO_(3)-PbTiO_(3)binary ceramics own both high Curie temperature and prominent piezoelectric properties,while the high dielectric loss needs to be reduced substantially for practical application especially at high t...BiScO_(3)-PbTiO_(3)binary ceramics own both high Curie temperature and prominent piezoelectric properties,while the high dielectric loss needs to be reduced substantially for practical application especially at high temperatures.In this work,a ternary perovskite system of(1-x-y)BiScO3-yPbTiO3-xBi(Mn_(2/3)Sb_(1/3))O_(3)(BS-yPT-xBMS)with x=0.005,y=0.630-0.645 and x=0.015,y=0.625-0.640 was prepared by the traditional solid-state reaction method.The phase structure,microstructure,dielectric/piezoelectric/ferroelectric properties were studied.Among BS-yPT-xBMS ceramic series,the BS-0.630PT-0.015BMS at morphotropic phase boundary possesses the reduced dielectric loss factor(tanδ=1.20%)and increased mechanical quality factor(Qm=84),and maintains a high Curie temperature(TC=410°C)and excellent piezoelectric properties(d_(33)=330 pC/N)simultaneously.Of particular importance,at elevated temperature of 200°C,the value of tanδis only increased to 1.59%.All these properties indicate that the BS-0.630PT-0.015BMS ceramic has great potential for application in high-temperature piezoelectric devices.展开更多
Two-dimensional(2D)van der Waals(vdW)materials provide the versatile playground to stack two or more vdW layers for creation of superior materials with desired properties.Here we theoretically adopt a twisted stack-en...Two-dimensional(2D)van der Waals(vdW)materials provide the versatile playground to stack two or more vdW layers for creation of superior materials with desired properties.Here we theoretically adopt a twisted stack-engineering of two LaBr_(2)monolayers to break space inversion symmetry for ferroelectricity and ultimately multiferroism.The enhancement and reversal of electric polarization are accompanied with the transition from interlayer ferromagnetic and antiferromagnetic orderings,demonstrating an effective magnetoelectric coupling effect with a mechanism dissimilar to that of the conventional multiferroics.Magnetization dynamics simulations show that such magnetic phase transition can excite topologically protected bimeron,and the skyrmion Hall effect can be suppressed by bilayer-bimeron stabilized in both ferromagnetic and antiferromagnetic configurations.Moreover,in the small-angle twisted moirésuperlattice,the uniform polarization will evolve into a staggered domain structure,accompanied with the appearance of bimeron,which forms a significant discrepancy with the non-twisted stack-engineered multiferroic LaBr_(2)bilayer.This work provides a strategy for 2D multiferroic materials by twisted stack engineering of magnetic single layers.展开更多
In the article titled,“A Versatile Surface Bioengineering Strategy Based on Mussel-Inspired and Bioclickable Peptide Mimic”[1],there was an error in Figure 2.In panel(e),the cell pictures of PEG after culture for 24...In the article titled,“A Versatile Surface Bioengineering Strategy Based on Mussel-Inspired and Bioclickable Peptide Mimic”[1],there was an error in Figure 2.In panel(e),the cell pictures of PEG after culture for 24 and 72 h were updated.The corrected figure is shown and is listed as Figure 1.展开更多
基金supported by Canadian Institutes for Health Research (CIHR)(to ADR and WW)Ontario Graduate Scholarship (to NOB)+2 种基金Alzheimer's Society of CanadaHeart and Stroke Foundation of Canada,CIHRthe Canadian Consortium for Neurodegeneration and Aging (CCNA)(to SNW)。
文摘Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial activation and neuroinflammation, edema, ischemia, vascular injury, energy failure, and peripheral immune cell infiltration. The timing of these events post injury has been linked to injury severity and functional outcome. Extracellular vesicles are membrane bound secretory vesicles that contain markers and cargo pertaining to their cell of origin and can cross the blood-brain barrier. These qualities make extracellular vesicles intriguing candidates for a liquid biopsy into the pathophysiologic changes occurring at the cellular level post traumatic brain injury. Herein, we review the most commonly reported cargo changes in extracellular vesicles from clinical traumatic brain injury samples. We then use knowledge from animal and in vitro models to help infer what these changes may indicate regrading cellular responses post traumatic brain injury. Future research should prioritize labeling extracellular vesicles with markers for distinct cell types across a range of timepoints post traumatic brain injury.
基金supported by the Innovation Fund Project of the Gansu Education Department(Grant No.2021B-099).
文摘The objective of reliability-based design optimization(RBDO)is to minimize the optimization objective while satisfying the corresponding reliability requirements.However,the nested loop characteristic reduces the efficiency of RBDO algorithm,which hinders their application to high-dimensional engineering problems.To address these issues,this paper proposes an efficient decoupled RBDO method combining high dimensional model representation(HDMR)and the weight-point estimation method(WPEM).First,we decouple the RBDO model using HDMR and WPEM.Second,Lagrange interpolation is used to approximate a univariate function.Finally,based on the results of the first two steps,the original nested loop reliability optimization model is completely transformed into a deterministic design optimization model that can be solved by a series of mature constrained optimization methods without any additional calculations.Two numerical examples of a planar 10-bar structure and an aviation hydraulic piping system with 28 design variables are analyzed to illustrate the performance and practicability of the proposed method.
基金The research was supported by the National Natural Science Foundation of China(Grant Nos.61435010,61675135,and 62005177)the National Natural Science Foundation for Young Scientists of China(Grant No.61905161)the Science and Technology Innovation Commission of Shenzhen(JCYJ20190808142415003).Authors also acknowledge the support from Instrumental Analysis Center of Shenzhen University(Xili Campus).
文摘Ammonia detection possesses great potential in atmosphere environmental protection,agriculture,industry,and rapid medical diagnosis.However,it still remains a great challenge to balance the sensitivity,selectivity,working temperature,and response/recovery speed.In this work,Berlin green(BG)framework is demonstrated as a highly promising sensing material for ammonia detection by both density functional theory simulation and experimental gas sensing investigation.Vacancy in BG framework offers abundant active sites for ammonia absorption,and the absorbed ammonia transfers sufficient electron to BG,arousing remarkable enhancement of resistance.Pristine BG framework shows remarkable response to ammonia at 50–110°C with the highest response at 80°C,which is jointly influenced by ammonia’s absorption onto BG surface and insertion into BG lattice.The sensing performance of BG can hardly be achieved at room temperature due to its high resistance.Introduction of conductive Ti3CN MXene overcomes the high resistance of pure BG framework,and the simply prepared BG/Ti3CN mixture shows high selectivity to ammonia at room temperature with satisfying response/recovery speed.
文摘The importance analysis method represents a powerful tool for quantifying the impact of input uncertainty on the output uncertainty.When an input variable is described by a specific interval rather than a certain probability distribution,the interval importance measure of input interval variable can be calculated by the traditional non-probabilistic importance analysis methods.Generally,the non-probabilistic importance analysis methods involve the Monte Carlo simulation(MCS)and the optimization-based methods,which both have high computational cost.In order to overcome this problem,this study proposes an interval important analytical method avoids the time-consuming optimization process.First,the original performance function is decomposed into a combination of a series of one-dimensional subsystems.Next,the interval of each variable is divided into several subintervals,and the response value of each one-dimensional subsystem at a specific input point is calculated.Then,the obtained responses are taken as specific values of the new input variable,and the interval importance is calculated by the approximated performance function.Compared with the traditional non-probabilistic importance analysis method,the proposed method significantly reduces the computational cost caused by the MCS and optimization process.In the proposed method,the number of function evaluations is equal to one plus the sum of the subintervals of all of the variables.The efficiency and accuracy of the proposed method are verified by five examples.The results show that the proposed method is not only efficient but also accurate.
基金This work was financially supported by the Natural Science Foundation of China(Nos.51832003 and 52003212)the Fun-damental Research Funds for the Central University(No.WUT 2020III034).
文摘Natural photosynthesis,which provides a green and high-efficiency energy conversion path by spatial separation of photogenerated carriers through combined actions of molecules ingeniously arranged in an efficient solar nanospace,highlights the importance of rational nanostructure design to realize artificial high-efficiency photosystem.Inspired by these unique features,we constructed a high-efficiency ternary photosystem by selectively decorating the{001}facets of 18-facet SrTiO_(3)with Au@CdS photosensitizers via a green photo-assisted method.Benefiting from the dual-facilitated charge carriers transportation in core-shell structured Au@CdS heterojunction and well-faceted 18-facet SrTiO_(3)nanocrystal,such a photo-catalyst could realize the effective spatial separation of photogenerated electrons and holes.As expected,the 18-facet SrTiO_(3)/Au@CdS photocatalyst exhibits superior activity in visible-light-driven photocatalytic hydrogen evolution(4.61 mmol h^(−1)g^(−1)),166%improvement in comparison with randomly deposited Au@CdS(1.73 mmol h^(−1)g^(−1)).This work offers new insight into the development of green and high-efficiency photocatalytic systems based on the rational nanostructure design by crystal facet engineering.
基金supported by the National Natural Science Foundation of China,under grant number 11861063.
文摘This paper considered a multi-stage sheep brucellosis model with incomplete immunity.First,we established a deterministic model,calculated the basic reproduction number R_(0),set out the conditions for the global stability of the disease-free equilibrium and endemic equilibrium.Second,considering the influence of environmental white noise on brucellosis infection,we further established the stochastic version of the model.By constructing a suitable Lyapunov function,we proved the existence and uniqueness of the global positive solution.Further,we got the sufficient conditions for disease extinction and the existence of ergodic stationary distribution.Finally,we carried out some numerical simulations to verify the theoretical results.
基金supported by the National Natural Science Foundation of China(Grant Nos.51972144 and U1806221)the Taishan Scholars Program,the Case-by-Case Project for Top Outstanding Talents of Jinan,the Shandong Provincial Natural Science Foundation(Grant No.ZR2020KA003)+2 种基金the Primary Research&Development Plan of Shandong Province(Grant No.2019JZZY010313)the Project of“20 Items of University”of Jinan(Grant Nos.T202009 and T201907)the Introduction Program of Senior Foreign Experts(G2021024003L).
文摘Lead-free(K_(0.5)Na_(0.5))NbO_(3)(KNN)and Li_(0.06)(K_(0.5)Na_(0.5))_(0.94)NbO_(3)(LKNN)thin films were fabricated by a sol-gel method.The effects of Li substitution on crystal structure,microstructure and electrical properties of KNN film were systematically studied.Li doping can enhance the ferroelectric and piezoelectric properties of KNN film.Compared with pure KNN film,the LKNN film possesses larger remanent polarization(P_(r)~9.3μC/cm^(2))and saturated polarization(P_(s)~41.2μC/cm^(2))and lower leakage current density(~10^(−5)A/cm^(2)at 200 kV/cm).Meanwhile,a typical butterfly shaped piezoelectric response curve is obtained in the LKNN film with a high piezoelectric coefficient(d_(33)~105 pm/V).Excellent fatigue resistance(~10^(9)switching cycles)and aging resistance(~180 days)demonstrate the long-term working stability of LKNN film.These findings indicate that KNN-based lead-free piezoelectric films have a broad application prospect in microelectromechanical systems(MEMS).
基金supported by the National Key R&D Program of China(2022YFB2502901)the Natural Science Foundation of China(U20A20334).
文摘Solving optimal control problems serves as the basic demand of industrial control tasks.Existing methods like model predictive control often suffer from heavy online computational burdens.Reinforcement learning has shown promise in computer and board games but has yet to be widely adopted in industrial applications due to a lack of accessible,high-accuracy solvers.Current Reinforcement learning(RL)solvers are often developed for academic research and require a significant amount of theoretical knowledge and programming skills.Besides,many of them only support Python-based environments and limit to model-free algorithms.To address this gap,this paper develops General Optimal control Problems Solver(GOPS),an easy-to-use RL solver package that aims to build real-time and high-performance controllers in industrial fields.GOPS is built with a highly modular structure that retains a flexible framework for secondary development.Considering the diversity of industrial control tasks,GOPS also includes a conversion tool that allows for the use of Matlab/Simulink to support environment construction,controller design,and performance validation.To handle large-scale problems,GOPS can automatically create various serial and parallel trainers by flexibly combining embedded buffers and samplers.It offers a variety of common approximate functions for policy and value functions,including polynomial,multilayer perceptron,convolutional neural network,etc.Additionally,constrained and robust algorithms for special industrial control systems with state constraints and model uncertainties are also integrated into GOPS.Several examples,including linear quadratic control,inverted double pendulum,vehicle tracking,humanoid robot,obstacle avoidance,and active suspension control,are tested to verify the performances of GOPS.
文摘近些年,我国成功开发了以煤为原料的甲醇制烯烃(Methanol to Olefins,MTO)生产工艺和技术,带动煤制烯烃产业的快速发展,保障了国家能源安全。流化床式反应器是MTO工业生产的核心反应装置,通过计算流体力学(Computational Fluid Dynamics,CFD)方法深入认知MTO流化床内的流化特性规律具有重要的意义,它可以从理论上更加准确地指导MTO流化床的优化与放大。本工作采用基于宏观-亚网格层次的气泡EMMS曳力和传统TFM耦合计算的多尺度CFD方法,对工业尺度MTO流化床内的多相流化行为进行了三维数值模拟。模拟结果表明,该多尺度CFD方法考虑了气泡结构对气-固相间曳力的影响,能较准确地预测MTO流化床内轴向颗粒浓度的"S-型"分布规律,且得到实验数据的验证;所预测的径向颗粒浓度分布呈现出经典的"环-核"分布规律,气体/颗粒的轴向时均速度在径向上的分布也与实际情况相互佐证,表明该多尺度CFD方法显著改善了基于均匀曳力的传统TFM对于宏观流场的预测能力。下一步工作将多尺度CFD方法拓展应用于MTO流化床优化放大及反应特性的研究。
基金Financial supports from the National Natural Science Foundation of China (No. NSFC51608446)the Natural Science Basic Research Plan of Shaanxi Province, China (No. 2017JQ1021)the Fundamental Research Fund for Central Universities (No. 3102018zy011)
文摘In an uncertainty scheme, reliability and global sensitivity analysis is studied in this work, to provide helpful information for probabilistic anti-resonance design of vibration systems.Discussions show that the resonance failure problem can be viewed as a series system, in which input uncertainties are modeled by random variables. In order to quantitatively measure the contributions of input variables to the system reliability, a global sensitivity index is proposed, the properties of which are also discussed. Then the proposed index is tested with an aeronautical hydraulic pipeline system, which is under the excitation of pump vibration and at a risk of resonance failure. Sensitivity results under different failure criteria and variation coefficients are obtained and studied, from which significant and insignificant input variables can be identified.The proposed method provides a relatively new insight for anti-resonance design of engineering structures.
基金supported by the National Natural Science Foundation of China(No.NSFC51608446)the Fundamental Research Fund for Central Universities of China(No.3102016ZY015)
文摘Traditional Global Sensitivity Analysis(GSA) focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is beyond the traditional GSA techniques.To fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function(RIMPDF) and Regional Importance Measure based on Cumulative Distribution Function(RIMCDF),are introduced to find out the contributions of specific regions of an input to the whole output distribution.The two regional importance measures prove to be reasonable supplements of the traditional GSA techniques.The ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.
文摘The impacts of petroleum contamination on the litter decomposition of shrub–grass land would directly influence nutrient cycling, and the stability and function of ecosystem. Ten common shrub and grass species from Yujiaping oil deposits were studied. Litters from these species were placed into litterbags and buried in petroleum-contaminated soil with 3levels of contamination(slight, moderate and serious pollution with petroleum concentrations of 15, 30 and 45 g/kg, respectively). A decomposition experiment was then conducted in the lab to investigate the impacts of petroleum contamination on litter decomposition rates. Slight pollution did not inhibit the decomposition of any litters and significantly promoted the litter decomposition of Hippophae rhamnoides, Caragana korshinskii, Amorpha fruticosa, Ziziphus jujuba var. spinosa, Periploca sepium, Medicago sativa and Bothriochloa ischaemum. Moderate pollution significantly inhibited litter decomposition of M. sativa,Coronilla varia, Artemisia vestita and Trrifolium repens and significantly promoted the litter decomposition of C. korshinskii, Z. jujuba var. spinosa and P. sepium. Serious pollution significantly inhibited the litter decomposition of H. rhamnoides, A. fruticosa, B. ischaemum and A. vestita and significantly promoted the litter decomposition of Z. jujuba var. spinosa, P.sepium and M. sativa. In addition, the impacts of petroleum contamination did not exhibit a uniform increase or decrease as petroleum concentration increased. Inhibitory effects of petroleum on litter decomposition may hinder the substance cycling and result in the degradation of plant communities in contaminated areas.
基金supported financially by the National Natural Science Foundation of China(Nos.51521001,51832003,51902236 and 31771032)。
文摘As one of the most delicate bioprocesses in nature,biosilicification is closely related to biosilica with various morphologies,and has provided abundant inspiration to materials synthesis.In the present study,to explore the biosilica formation process and fabricate silica with an exquisite microstructure for lithiumion battery(LIB)electrodes,a bacterial phage(M13)is used as a biotemplate to synthesize silica with diverse morphologies:cylinders,hexagonal prisms,assemblies of smaller cylinders and nanowires.A facile ethanol bath method is conducted to coat the nanowires with nitrogen-containing carbon and carbon-coated SiO_(2) nanowires with mesochannels(C@msSiO_(2) NWs)are first used as anode materials for LIBs.Attributed to the uniform carbon coating and parallel mesochannel structure,the electronic conductivity and capacity to accommodate volume variations were significantly improved.In the electrochemical perfo rmance test,the composites calcined at 750℃(C@msSiO_(2) NWs-750)show an impressive capacity of 653 mA h g^(-1) at a current density of 500 mA g^(-1) and stability(1000 cycles).In view of the electrochemical test outcomes,the prepa ration of a sophisticated structure with an outstanding potential is easily achieved via a biomimetic strategy.
基金This work was supported by the National Key Research and Development Program of China(2019YFA0112000 and 2017YFB0702504)the National Natural Science Foundation of China(31570957 and 21875092)+2 种基金the International Cooperation Project by Science and Technology Department of Sichuan Province(2019YFH0103)the Applied Basic Research Project funded by Science and Technology Department of Sichuan Province(2017JY0296)the Innovation and Entrepreneurship Program of Jiangsu Province,and the Six Talent Peaks Project in Jiangsu Province(2018-XCL-013).
文摘In this work,we present a versatile surface engineering strategy by the combination of mussel adhesive peptide mimicking and bioorthogonal click chemistry.The main idea reflected in this work derived from a novel mussel-inspired peptide mimic with a bioclickable azide group(i.e.,DOPA_(4)-azide).Similar to the adhesion mechanism of the mussel foot protein(i.e.,covalent/noncovalent comediated surface adhesion),the bioinspired and bioclickable peptide mimic DOPA_(4)-azide enables stable binding on a broad range of materials,such as metallic,inorganic,and organic polymer substrates.In addition to the material universality,the azide residues of DOPA_(4)-azide are also capable of a specific conjugation of dibenzylcyclooctyne-(DBCO-)modified bioactive ligands through bioorthogonal click reaction in a second step.To demonstrate the applicability of this strategy for diversified biofunctionalization,we bioorthogonally conjugated several typical bioactive molecules with DBCO functionalization on different substrates to fabricate functional surfaces which fulfil essential requirements of biomedically used implants.For instance,antibiofouling,antibacterial,and antithrombogenic properties could be easily applied to the relevant biomaterial surfaces,by grafting antifouling polymer,antibacterial peptide,and NO-generating catalyst,respectively.Overall,the novel surface bioengineering strategy has shown broad applicability for both the types of substrate materials and the expected biofunctionalities.Conceivably,the“clean”molecular modification of bioorthogonal chemistry and the universality of mussel-inspired surface adhesion may synergically provide a versatile surface bioengineering strategy for a wide range of biomedical materials.
基金supported by the National Natural Science Foundation of China (No. 81973261)the Foundation of West China Hospital of Stomatology (No. RD-02–201903)the Research Funding from West China School/Hospital of Stomatology, Sichuan University (No. RCDWJS2020–7)。
文摘Cancer is a serious threat to humans due to its high mortality. The efforts to fully understand cancer and to fight against it have never been stopped. The traditional therapies, such as surgery, radiotherapy and chemotherapy, are useful but cannot meet the increasing demands of patients. As such, novel approaches against cancer are urgently required. It has been found that the acidic tumor microenvironment plays important roles in promoting the cancer progression. In recent years, sodium bicarbonate(NaHCO_(3)), a simple inorganic salt, has been found to be able to reverse the p H of tumor microenvironment and inhibit the invasion, metastasis, immune evasion, drug resistance and hypoxia of tumor cells. Thus, NaHCO_(3)-based therapy is a potential approach for the treatment of cancer, and the related studies have been increasingly reported. Herein, we aim to provide a comprehensive understanding of the acidic tumor microenvironment and summarize the applications and mechanisms of Na HCO_(3)in cancer therapy. The combination of Na HCO;with chemotherapy, immunotherapy or nanoparticles systems is discussed. In addition, the concerns of Na HCO_(3)in clinical use and the potential ways to use Na HCO_(3)for cancer therapy are also discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.51972144,U1806221 and U2006218)the Shandong Provincial Natural Science Foundation(Grant No.ZR2020KA003)+2 种基金the Project of“20 Items of University”of Jinan(Grant Nos.T202009 and T201907)the Introduction Program of Senior Foreign Experts(G2021024003L)the Shandong Provincial Key Research and Development Plan(Grant No.2022CXPT045).
文摘The BiFeO3-based film is one of the most promising candidates for lead-free piezoelectric film devices.In this work,the 1μm-thick Bi(Fe_(0.93)Mn_(0.05)Ti_(0.02))O_(3)(BFMT)films are grown on the ITO/glass substrate using a sol-gel method combined with spin-coating and layer-by-layer annealing technique.These films display a large saturated polarization of 95μC/cm^(2),and a remanent polarization of 70μC/cm^(2).Especially,the films are self-poled caused by an internal bias field,giving rise to asymmetric polarization-electric field(P-E)loops with a positive shift along the x-axis.A stable self-polarization state is maintained during the applied electric field increasing to 1500 kV/cm and then decreasing back.The weak dependence of P-E loops on frequency(1-50 kHz)and temperature(25-125°C)indicate that the internal bias field can be stable within a certain frequency and temperature range.These results demonstrate that the self-polarized BFMT thick films can be integrated into devices without any poling process,with promising applications in micro-electro-mechanical systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.51972144,U1806221 and U2006218)the Taishan Scholars Program,the Case-by-Case Project for Top Outstanding Talents of Jinan,the Shandong Provincial Natural Science Foundation(Grant No.ZR2020KA003)+2 种基金the Primary Research&Development Plan of Shandong Province(Grant No.2019JZZY010313)the Project of“20 Items of University”of Jinan(Grant Nos.T202009 and T201907)the Introduction Program of Senior Foreign Experts(G2021024003L).
文摘BiScO_(3)-PbTiO_(3)binary ceramics own both high Curie temperature and prominent piezoelectric properties,while the high dielectric loss needs to be reduced substantially for practical application especially at high temperatures.In this work,a ternary perovskite system of(1-x-y)BiScO3-yPbTiO3-xBi(Mn_(2/3)Sb_(1/3))O_(3)(BS-yPT-xBMS)with x=0.005,y=0.630-0.645 and x=0.015,y=0.625-0.640 was prepared by the traditional solid-state reaction method.The phase structure,microstructure,dielectric/piezoelectric/ferroelectric properties were studied.Among BS-yPT-xBMS ceramic series,the BS-0.630PT-0.015BMS at morphotropic phase boundary possesses the reduced dielectric loss factor(tanδ=1.20%)and increased mechanical quality factor(Qm=84),and maintains a high Curie temperature(TC=410°C)and excellent piezoelectric properties(d_(33)=330 pC/N)simultaneously.Of particular importance,at elevated temperature of 200°C,the value of tanδis only increased to 1.59%.All these properties indicate that the BS-0.630PT-0.015BMS ceramic has great potential for application in high-temperature piezoelectric devices.
基金We acknowledge grants from the National Natural Science Foundation of China under research(Nos.52102238,51571083,and 11674083)Henan University(No.CX3040A0950115,CJ3050A0670499,CJ3050A0670524)+2 种基金H.L.acknowledges the support from the National Natural Science Foundation of China(Grant No.11804078)Henan University(Grant No.CJ3050A0240050)Z.X.C.thanks Australia Research Council for support(DP190100150).
文摘Two-dimensional(2D)van der Waals(vdW)materials provide the versatile playground to stack two or more vdW layers for creation of superior materials with desired properties.Here we theoretically adopt a twisted stack-engineering of two LaBr_(2)monolayers to break space inversion symmetry for ferroelectricity and ultimately multiferroism.The enhancement and reversal of electric polarization are accompanied with the transition from interlayer ferromagnetic and antiferromagnetic orderings,demonstrating an effective magnetoelectric coupling effect with a mechanism dissimilar to that of the conventional multiferroics.Magnetization dynamics simulations show that such magnetic phase transition can excite topologically protected bimeron,and the skyrmion Hall effect can be suppressed by bilayer-bimeron stabilized in both ferromagnetic and antiferromagnetic configurations.Moreover,in the small-angle twisted moirésuperlattice,the uniform polarization will evolve into a staggered domain structure,accompanied with the appearance of bimeron,which forms a significant discrepancy with the non-twisted stack-engineered multiferroic LaBr_(2)bilayer.This work provides a strategy for 2D multiferroic materials by twisted stack engineering of magnetic single layers.
文摘In the article titled,“A Versatile Surface Bioengineering Strategy Based on Mussel-Inspired and Bioclickable Peptide Mimic”[1],there was an error in Figure 2.In panel(e),the cell pictures of PEG after culture for 24 and 72 h were updated.The corrected figure is shown and is listed as Figure 1.
