AIM: To examine the effect of aberrant methylation of the KISS1 promoter on the development of colorectal cancer (CRC) and to investigate reversing aberrant methylation of the KISS1 promoter as a potential therapeutic...AIM: To examine the effect of aberrant methylation of the KISS1 promoter on the development of colorectal cancer (CRC) and to investigate reversing aberrant methylation of the KISS1 promoter as a potential therapeutic target.展开更多
Studies have shown that micro-wedge vortex generators(MVG)can effectively control the flow separation of supersonic boundary layer.In order to improve the flight stability of spinning projectile,the original standard ...Studies have shown that micro-wedge vortex generators(MVG)can effectively control the flow separation of supersonic boundary layer.In order to improve the flight stability of spinning projectile,the original standard 155 mm projectile was taken as an example,and the micro-vanes were mounted at the projectile shoulder to investigate the separation control on the aerodynamic characteristics of projectile.Numerical simulations were performed with the use of DES method for the flow fields of projectiles with and without micro-vanes,and the characteristics of the boundary layer structures and aerodynamic data were compared and discussed.Numerical results show that the micro-vanes can be used to inhibit separation of fluid on projectile surface,and improve the flight stability and firing dispersion of projectile.展开更多
The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain,the transition zone between the Dabie Moun...The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain,the transition zone between the Dabie Mountain Area and Jianghan Plain.It’s a great field test site to study the material and energy exchange among rainfall,soil moisture,and groundwater of the Earth’s critical zone in subtropical monsoon climate plain areas.This paper analyzed the connection between rainfall and volume water content(VWC)of soil at different depths of several soil profiles,and the dynamic feature of groundwater was discussed,which reveals the rainfall infiltration recharge of Quaternary Upper Pleistocene strata.The results show that the Quaternary Upper Pleistocene aquifer groundwater accepts a little direct rainfall recharge,while the lateral recharge is the main supplement source.There were 75 effective rainfall events among 120 rainfall events during the monitoring period,with an accumulated amount of 672.9 mm,and the percentages of effective rainfall amount and duration time were 62.50%and 91.56%,respectively.The max evaporation depth at the upper part in Quaternary cohesive soil was no less than 1.4 m.The soil profile was divided into four zones:(1)The sensitive zone of rainfall infiltration within 1.4 m,where the material and energy exchange frequently near the interface between atmosphere and soil;(2)the buffer zone of rainfall infiltration between 1.4 m and 3.5 m;(3)the migration zone of rainfall infiltration between 3.5 m and 5.0 m;and(4)the rainfall infiltration and groundwater level co-influenced zone below 5.0 m.The results revealed the reaction of soil moisture and groundwater to rainfall in the area covered by cohesive soil under humid climate in Earth’s critical zone,which is of great theoretical and practical significance for groundwater resources evaluation and development,groundwater environmental protection,ecological environmental improvement,drought disaster prevention,and flood disaster prevention in subtropical monsoon climate plain areas.展开更多
The deflectable nose missile has a longer range by deflecting its nose to improve its aerodynamic feature.Based on detached eddy simulation(DES), the supersonic flow fields of a missile with deflectable nose are simul...The deflectable nose missile has a longer range by deflecting its nose to improve its aerodynamic feature.Based on detached eddy simulation(DES), the supersonic flow fields of a missile with deflectable nose are simulated numerically and its aerodynamic force coefficients are calculated under the condition of the deflection angles vary from 0° to 8°, angles of attack, 0°-8°, and mach numbers, 2 to 5. Coupling these aerodynamic coefficients with the plumb plane ballistic equations, the extended flight range has been calculated. Furthermore, the genetic algorithm(GA) is employed for the solution of maximum range of the deflected missile.展开更多
Magnetic skyrmions, with topologically protected particle-like magnetization configurations, are promising information carriers for future spintronics devices with ultralow energy consumption. Generally, during motion...Magnetic skyrmions, with topologically protected particle-like magnetization configurations, are promising information carriers for future spintronics devices with ultralow energy consumption. Generally, during motion, skyrmions suffer from the skyrmion Hall effect(Sk HE) wherein the skyrmions deflect away from the intended path of the driving force.Numerous methods have been proposed to avoid this detrimental effect. In this study, we propose controllable alternating current(AC)-driven skyrmion propagation in a ferromagnetic nanowire based on combination of gate-voltage-controlled magnetic anisotropy(VCMA) and Sk HE. Micromagnetic simulations show that a skyrmion oscillatory closed-loop-like in situ motion driven by AC can be transformed into directional ratchet-like propagation along the nanotrack by creating a VCMA-gate barrier. Additionally, we show that the skyrmion propagation conditions depend on the gate barrier potential and driving AC parameters, and they can be used for the optimal design of nanotrack devices. Moreover, this mechanism could be used to control skyrmion macroscopic propagation directions by dynamically alternating the voltage of another series of gates. We further show the dynamic control of the long-distance propagation of skyrmions along with the pinning state. The study results provide a promising route for designing future skyrmion-based spintronics logical and memory devices.展开更多
BACKGROUND Tumor recurrence and metastasis lead to a poor prognosis in colorectal cancer(CRC).Necroptosis is closely related to the tumor microenvironment(TME)and affects tumor recurrence and metastasis.We aimed to st...BACKGROUND Tumor recurrence and metastasis lead to a poor prognosis in colorectal cancer(CRC).Necroptosis is closely related to the tumor microenvironment(TME)and affects tumor recurrence and metastasis.We aimed to stratify CRC patients according to necroptosis-related long noncoding RNAs(lncRNAs),which can be used to not only evaluate prognosis and improve precision medicine in clinical practice but also screen potential immunotherapy drugs.AIM To stratify CRC patients according to necroptosis-related lncRNAs(NRLs),which can be used to not only evaluate prognosis and improve precision medicine in clinical practice but also screen potential immunotherapy drugs.METHODS LncRNA expression profiles were collected from The Cancer Genome Atlas.NRLs were identified by coexpression analysis.Cox regression analysis identified a NRL signature.Then,the value of this signature was comprehensively and multidimensionally evaluated,and its reliability for CRC prognosis prediction was assessed with clinical CRC data and compared with that of six other lncRNA were also performed according to the risk score(RS)of the signature.RESULTS An 8-lncRNA signature significantly associated with overall survival(OS)was constructed,and its reliability was validated with clinical CRC data.Most of the areas under the receiver operating characteristic curves(AUCs)values for 1-,3-and 5-year OS for this signature were higher than those for the other six lncRNA signatures.OS,disease-specific survival and the progression-free interval were all significantly poorer in the high-risk group.The RS of the signature showed good concordance with the predicted prognosis,with AUCs for 1-,3-and 5-year OS of 0.79,0.81 and 0.77,respectively.Additionally,the calibration plots for this signature combined with clinical factors showed that this combination could effectively improve the ability to predict OS.The RS was correlated with tumor stage,lymph node metastasis and distant metastasis.Most of the enriched Kyoto Encyclopedia of Genes and Genomes and Gene Ontology terms were tumor metastasis-related pathways in the high-risk group;these patients showed greater infiltration of immunosuppressive cells,such as cancer-associated fibroblasts,hematopoietic stem cells and M2 macrophages,but less infiltration of infiltrating antitumor effector immune cells,such as cluster of differentiation 8+T cells and regulatory T cells(Tregs).We explored additional potential immune checkpoint genes and potential immunotherapeutic and chemotherapeutic drugs with relatively low IC_(50) values.CONCLUSION We identified an NRL signature with strong fidelity that could stably predict prognosis and might be an indicator of the TME of CRC.Furthermore,additional potential immunotherapeutic and chemotherapeutic drugs were explored.展开更多
Objective: The azoospermia is increasingly becoming prevalent year by year,which has been plaguing a great number of infertile couples. Testes biopsy is a gold index to evaluate the testicular spermatogenesis in patie...Objective: The azoospermia is increasingly becoming prevalent year by year,which has been plaguing a great number of infertile couples. Testes biopsy is a gold index to evaluate the testicular spermatogenesis in patients with anspermia. However, it is more invasive and may not accurately reflect the whole spermatogenic function of the testes. In recent years, with the continuous development of ultrasound and assisted reproductive technology, real-time sonoelastography has been widely applied in the evaluation of spermatogenic function in patients with azoospermia. It is still at the initial stage, but shows good application prospects. In this paper, we will summarize and review the present status of male infertility and the clinical application and research progress of real-time sonoelastography in the evaluation of the testicular spermatogenic function of non-obstructive azoospermia patients.展开更多
Background: In the past decades, studies on infant anemia have mainly focused on rural areas of China. With the increasing heterogeneity of population in recent years, available information on infant anemia is inconc...Background: In the past decades, studies on infant anemia have mainly focused on rural areas of China. With the increasing heterogeneity of population in recent years, available information on infant anemia is inconclusive in large cities of China, especially with comparison between native residents and floating population. This population-based cross-sectional study was implemented to determine the anemic status of infants as well as the risk factors in a representative downtown area of Beijing. Methods: As useful methods to build a predictive model, Chi-squared automatic interaction detection (CHAID) decision tree analysis and logistic regression analysis were introduced to explore risk factors of infant anemia. A total of 1091 infants aged 6-12 months together with their parents/caregivers living at Heping Avenue Subdistrict of Beijing were surveyed from January 1,2013 to December 31, 2014. Results: The prevalence of anemia was 12.60% with a range of 3.47%-40.00% in different subgroup characteristics. The CHAID decision tree model has demonstrated multilevel interaction among risk factors through stepwise pathways to detect anemia. Besides the three predictors identified by logistic regression model including maternal anemia during pregnancy, exclusive breastfeeding in the first 6 months, and floating population, CHAID decision tree analysis also identified the fourth risk factor, the maternal educational level, with higher overall classification accuracy and larger area below the receiver operating characteristic curve. Conclusions: The infant anemic status in metropolis is complex and should be carefully considered by the basic health care practitioners. CHAID decision tree analysis has demonstrated a better performance in hierarchical analysis of population with great heterogeneity. Risk factors identified by this study might be meaningful in the early detection and prompt treatment of infant anemia in large cities.展开更多
A new discrete Boltzmann model, the discrete ellipsoidal statistical Bhatnagar-Gross-Krook (ES- BGK) model, is proposed to simulate nonequilibrium compressible flows. Compared with the original discrete BGK model, t...A new discrete Boltzmann model, the discrete ellipsoidal statistical Bhatnagar-Gross-Krook (ES- BGK) model, is proposed to simulate nonequilibrium compressible flows. Compared with the original discrete BGK model, the discrete ES-BGK has a flexible Prandtl number. For the discrete ES-BGK model in the Burnett level, two kinds of discrete velocity model are introduced and the relations between nonequilibrium quantities and the viscous stress and heat flux in the Burnett level are established. The model is verified via four benchmark tests. In addition, a new idea is introduced to recover the actual distribution function through the macroscopic quantities and their space derivatives. The recovery scheme works not only for discrete Boltzmann simulation but also for hydrodynamic ones, for example, those based on the Navier-Stokes or the Burnett equations.展开更多
The rarefied effect of gas flow in microchannel is significant and cannot be well described by traditional hydrodynamic models. It has been known that discrete Boltzmann model(DBM) has the potential to investigate flo...The rarefied effect of gas flow in microchannel is significant and cannot be well described by traditional hydrodynamic models. It has been known that discrete Boltzmann model(DBM) has the potential to investigate flows in a relatively wider range of Knudsen number because of its intrinsic kinetic nature inherited from Boltzmann equation.It is crucial to have a proper kinetic boundary condition for DBM to capture the velocity slip and the flow characteristics in the Knudsen layer. In this paper, we present a DBM combined with Maxwell-type boundary condition model for slip flow. The tangential momentum accommodation coefficient is introduced to implement a gas-surface interaction model.Both the velocity slip and the Knudsen layer under various Knudsen numbers and accommodation coefficients can be well described. Two kinds of slip flows, including Couette flow and Poiseuille flow, are simulated to verify the model.To dynamically compare results from different models, the relation between the definition of Knudsen number in hard sphere model and that in BGK model is clarified.展开更多
A one-dimensional discrete Boltzmann model for detonation simulation is presented. Instead of numerical solving Navier-Stokes equations, this model obtains the information of flow field through numerical solving speci...A one-dimensional discrete Boltzmann model for detonation simulation is presented. Instead of numerical solving Navier-Stokes equations, this model obtains the information of flow field through numerical solving specially discretized Boltzmann equation. Several classical benchmarks including Sod shock wave tube, Colella explosion problem,and one-dimensional self-sustainable stable detonation are simulated to validate the new model. Based on the new model,the influence of negative temperature coefficient of reaction rate on detonation is further investigated. It is found that an abnormal detonation with two wave heads periodically appears under negative temperature coefficient condition.The causes of the abnormal detonation are analyzed. One typical cycle of the periodic abnormal detonation and its development process are discussed.展开更多
Emergency exercises are an efficient approach for preventing serious damage and harm, including loss of life and property and a wide range of adverse social effects, during various public emergencies. Among various fa...Emergency exercises are an efficient approach for preventing serious damage and harm, including loss of life and property and a wide range of adverse social effects, during various public emergencies. Among various factors affecting the value of emergency exercises, including their design, development, conduct, evaluation, and improvement planning, this paper emphasizes the focal role of evacuees and their behavior. We address two concerns: What are the intrinsic reasons behind human behavior? How do we model and exhibit human behavior? We review studies investigating the mechanisms of psychological behavior and crowd evacuation animation. A comprehensive analysis of logical patterns of behavior and crowd evacuation is presented first. The interactive effects of information (objective and subjective), psychology (panic, small groups, and conflicting roles), and six kinds of behavior contribute to a more effective understanding of an emergency scene and assist in making scientific decisions. Based on these studies, a wide range of perspectives on crowd formation and evacuation animation models is summa- rized. Collision avoidance is underlined as a special topic. Finally, this paper highlights some of the technical challenges and key questions to be addressed by future developments in this rapidly developing field.展开更多
We synthesize animations from a single image by transferring fluid motion of a video example globally.Given a target image of a fluid scene,an alpha matte is required to extract the fluid region.Our method needs to ad...We synthesize animations from a single image by transferring fluid motion of a video example globally.Given a target image of a fluid scene,an alpha matte is required to extract the fluid region.Our method needs to adjust a user-specified video example for producing the fluid motion suitable for the extracted fluid region.Employing the fluid video database,the flow field of the target image is obtained by warping the optical flow of a video frame that has a visually similar scene to the target image according to their scene correspondences,which assigns fluid orientation and speed automatically.Results show that our method is successful in preserving large fluid features in the synthesized animations.In comparison to existing approaches,it is both possible and useful to utilize our method to create flow animations with higher quality.展开更多
Flattening of the interfaces is necessary in computing wave propagation along strati?ed waveguides in large range step sizes while using marching methods. When the supposition that there exists one horizontal straight...Flattening of the interfaces is necessary in computing wave propagation along strati?ed waveguides in large range step sizes while using marching methods. When the supposition that there exists one horizontal straight line in two adjacent interfaces does not hold, the previously suggested local orthogonal transform method with an analytical formulation is not feasible. This paper presents a numerical coordinate transform and an equation transform to perform the transforms numerically for waveguides without satisfying the supposition. The boundary value problem is then reduced to an initial value problem by one-way reformulation based on the Dirichlet-to-Neumann (DtN) map. This method is applicable in solving long-range wave propagation problems in slowly varying waveguides with a multilayered medium structure.展开更多
基金Supported by Natural Science Fund of Fujian Province,No.2013-J01291National Key Construction Projects Clinical Specialties
文摘AIM: To examine the effect of aberrant methylation of the KISS1 promoter on the development of colorectal cancer (CRC) and to investigate reversing aberrant methylation of the KISS1 promoter as a potential therapeutic target.
文摘Studies have shown that micro-wedge vortex generators(MVG)can effectively control the flow separation of supersonic boundary layer.In order to improve the flight stability of spinning projectile,the original standard 155 mm projectile was taken as an example,and the micro-vanes were mounted at the projectile shoulder to investigate the separation control on the aerodynamic characteristics of projectile.Numerical simulations were performed with the use of DES method for the flow fields of projectiles with and without micro-vanes,and the characteristics of the boundary layer structures and aerodynamic data were compared and discussed.Numerical results show that the micro-vanes can be used to inhibit separation of fluid on projectile surface,and improve the flight stability and firing dispersion of projectile.
基金the project“1:50000 regional hydrogeological survey in the Dabie Mountains contiguous destitute area”(121201009000172522)from Wuhan Center of Geological Survey,China Geological Survey(CGS).
文摘The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain,the transition zone between the Dabie Mountain Area and Jianghan Plain.It’s a great field test site to study the material and energy exchange among rainfall,soil moisture,and groundwater of the Earth’s critical zone in subtropical monsoon climate plain areas.This paper analyzed the connection between rainfall and volume water content(VWC)of soil at different depths of several soil profiles,and the dynamic feature of groundwater was discussed,which reveals the rainfall infiltration recharge of Quaternary Upper Pleistocene strata.The results show that the Quaternary Upper Pleistocene aquifer groundwater accepts a little direct rainfall recharge,while the lateral recharge is the main supplement source.There were 75 effective rainfall events among 120 rainfall events during the monitoring period,with an accumulated amount of 672.9 mm,and the percentages of effective rainfall amount and duration time were 62.50%and 91.56%,respectively.The max evaporation depth at the upper part in Quaternary cohesive soil was no less than 1.4 m.The soil profile was divided into four zones:(1)The sensitive zone of rainfall infiltration within 1.4 m,where the material and energy exchange frequently near the interface between atmosphere and soil;(2)the buffer zone of rainfall infiltration between 1.4 m and 3.5 m;(3)the migration zone of rainfall infiltration between 3.5 m and 5.0 m;and(4)the rainfall infiltration and groundwater level co-influenced zone below 5.0 m.The results revealed the reaction of soil moisture and groundwater to rainfall in the area covered by cohesive soil under humid climate in Earth’s critical zone,which is of great theoretical and practical significance for groundwater resources evaluation and development,groundwater environmental protection,ecological environmental improvement,drought disaster prevention,and flood disaster prevention in subtropical monsoon climate plain areas.
文摘The deflectable nose missile has a longer range by deflecting its nose to improve its aerodynamic feature.Based on detached eddy simulation(DES), the supersonic flow fields of a missile with deflectable nose are simulated numerically and its aerodynamic force coefficients are calculated under the condition of the deflection angles vary from 0° to 8°, angles of attack, 0°-8°, and mach numbers, 2 to 5. Coupling these aerodynamic coefficients with the plumb plane ballistic equations, the extended flight range has been calculated. Furthermore, the genetic algorithm(GA) is employed for the solution of maximum range of the deflected missile.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51902300,11972333,and 11902316)the Natural Science Foundation of Zhejiang Province,China(Grant Nos.LY21F010011,LZ19A020001,and LZ23A020002)the Fundamental Research Funds for the Provincial Universities of Zhejiang(Grant Nos.2021YW02 and 2022YW88)。
文摘Magnetic skyrmions, with topologically protected particle-like magnetization configurations, are promising information carriers for future spintronics devices with ultralow energy consumption. Generally, during motion, skyrmions suffer from the skyrmion Hall effect(Sk HE) wherein the skyrmions deflect away from the intended path of the driving force.Numerous methods have been proposed to avoid this detrimental effect. In this study, we propose controllable alternating current(AC)-driven skyrmion propagation in a ferromagnetic nanowire based on combination of gate-voltage-controlled magnetic anisotropy(VCMA) and Sk HE. Micromagnetic simulations show that a skyrmion oscillatory closed-loop-like in situ motion driven by AC can be transformed into directional ratchet-like propagation along the nanotrack by creating a VCMA-gate barrier. Additionally, we show that the skyrmion propagation conditions depend on the gate barrier potential and driving AC parameters, and they can be used for the optimal design of nanotrack devices. Moreover, this mechanism could be used to control skyrmion macroscopic propagation directions by dynamically alternating the voltage of another series of gates. We further show the dynamic control of the long-distance propagation of skyrmions along with the pinning state. The study results provide a promising route for designing future skyrmion-based spintronics logical and memory devices.
基金Supported by the Joint Funds for the Innovation of Science and Technology,Fujian Province,No.2019Y9133.
文摘BACKGROUND Tumor recurrence and metastasis lead to a poor prognosis in colorectal cancer(CRC).Necroptosis is closely related to the tumor microenvironment(TME)and affects tumor recurrence and metastasis.We aimed to stratify CRC patients according to necroptosis-related long noncoding RNAs(lncRNAs),which can be used to not only evaluate prognosis and improve precision medicine in clinical practice but also screen potential immunotherapy drugs.AIM To stratify CRC patients according to necroptosis-related lncRNAs(NRLs),which can be used to not only evaluate prognosis and improve precision medicine in clinical practice but also screen potential immunotherapy drugs.METHODS LncRNA expression profiles were collected from The Cancer Genome Atlas.NRLs were identified by coexpression analysis.Cox regression analysis identified a NRL signature.Then,the value of this signature was comprehensively and multidimensionally evaluated,and its reliability for CRC prognosis prediction was assessed with clinical CRC data and compared with that of six other lncRNA were also performed according to the risk score(RS)of the signature.RESULTS An 8-lncRNA signature significantly associated with overall survival(OS)was constructed,and its reliability was validated with clinical CRC data.Most of the areas under the receiver operating characteristic curves(AUCs)values for 1-,3-and 5-year OS for this signature were higher than those for the other six lncRNA signatures.OS,disease-specific survival and the progression-free interval were all significantly poorer in the high-risk group.The RS of the signature showed good concordance with the predicted prognosis,with AUCs for 1-,3-and 5-year OS of 0.79,0.81 and 0.77,respectively.Additionally,the calibration plots for this signature combined with clinical factors showed that this combination could effectively improve the ability to predict OS.The RS was correlated with tumor stage,lymph node metastasis and distant metastasis.Most of the enriched Kyoto Encyclopedia of Genes and Genomes and Gene Ontology terms were tumor metastasis-related pathways in the high-risk group;these patients showed greater infiltration of immunosuppressive cells,such as cancer-associated fibroblasts,hematopoietic stem cells and M2 macrophages,but less infiltration of infiltrating antitumor effector immune cells,such as cluster of differentiation 8+T cells and regulatory T cells(Tregs).We explored additional potential immune checkpoint genes and potential immunotherapeutic and chemotherapeutic drugs with relatively low IC_(50) values.CONCLUSION We identified an NRL signature with strong fidelity that could stably predict prognosis and might be an indicator of the TME of CRC.Furthermore,additional potential immunotherapeutic and chemotherapeutic drugs were explored.
基金Natural Science Foundation of Hubei Province(2016CFC749).
文摘Objective: The azoospermia is increasingly becoming prevalent year by year,which has been plaguing a great number of infertile couples. Testes biopsy is a gold index to evaluate the testicular spermatogenesis in patients with anspermia. However, it is more invasive and may not accurately reflect the whole spermatogenic function of the testes. In recent years, with the continuous development of ultrasound and assisted reproductive technology, real-time sonoelastography has been widely applied in the evaluation of spermatogenic function in patients with azoospermia. It is still at the initial stage, but shows good application prospects. In this paper, we will summarize and review the present status of male infertility and the clinical application and research progress of real-time sonoelastography in the evaluation of the testicular spermatogenic function of non-obstructive azoospermia patients.
文摘Background: In the past decades, studies on infant anemia have mainly focused on rural areas of China. With the increasing heterogeneity of population in recent years, available information on infant anemia is inconclusive in large cities of China, especially with comparison between native residents and floating population. This population-based cross-sectional study was implemented to determine the anemic status of infants as well as the risk factors in a representative downtown area of Beijing. Methods: As useful methods to build a predictive model, Chi-squared automatic interaction detection (CHAID) decision tree analysis and logistic regression analysis were introduced to explore risk factors of infant anemia. A total of 1091 infants aged 6-12 months together with their parents/caregivers living at Heping Avenue Subdistrict of Beijing were surveyed from January 1,2013 to December 31, 2014. Results: The prevalence of anemia was 12.60% with a range of 3.47%-40.00% in different subgroup characteristics. The CHAID decision tree model has demonstrated multilevel interaction among risk factors through stepwise pathways to detect anemia. Besides the three predictors identified by logistic regression model including maternal anemia during pregnancy, exclusive breastfeeding in the first 6 months, and floating population, CHAID decision tree analysis also identified the fourth risk factor, the maternal educational level, with higher overall classification accuracy and larger area below the receiver operating characteristic curve. Conclusions: The infant anemic status in metropolis is complex and should be carefully considered by the basic health care practitioners. CHAID decision tree analysis has demonstrated a better performance in hierarchical analysis of population with great heterogeneity. Risk factors identified by this study might be meaningful in the early detection and prompt treatment of infant anemia in large cities.
基金The authors would like to acknowledge the support of the National Natural Science Foundation of China (Grant Nos. 11475028, 11772064, 11502117, and U1530261), and Science Challenge Project (Grant Nos. JCKY2016212A501 and TZ2016002).
文摘A new discrete Boltzmann model, the discrete ellipsoidal statistical Bhatnagar-Gross-Krook (ES- BGK) model, is proposed to simulate nonequilibrium compressible flows. Compared with the original discrete BGK model, the discrete ES-BGK has a flexible Prandtl number. For the discrete ES-BGK model in the Burnett level, two kinds of discrete velocity model are introduced and the relations between nonequilibrium quantities and the viscous stress and heat flux in the Burnett level are established. The model is verified via four benchmark tests. In addition, a new idea is introduced to recover the actual distribution function through the macroscopic quantities and their space derivatives. The recovery scheme works not only for discrete Boltzmann simulation but also for hydrodynamic ones, for example, those based on the Navier-Stokes or the Burnett equations.
基金Support of National Natural Science Foundation of China under Grant Nos.11475028,11772064,and 11502117Science Challenge Project under Grant Nos.JCKY2016212A501 and TZ2016002
文摘The rarefied effect of gas flow in microchannel is significant and cannot be well described by traditional hydrodynamic models. It has been known that discrete Boltzmann model(DBM) has the potential to investigate flows in a relatively wider range of Knudsen number because of its intrinsic kinetic nature inherited from Boltzmann equation.It is crucial to have a proper kinetic boundary condition for DBM to capture the velocity slip and the flow characteristics in the Knudsen layer. In this paper, we present a DBM combined with Maxwell-type boundary condition model for slip flow. The tangential momentum accommodation coefficient is introduced to implement a gas-surface interaction model.Both the velocity slip and the Knudsen layer under various Knudsen numbers and accommodation coefficients can be well described. Two kinds of slip flows, including Couette flow and Poiseuille flow, are simulated to verify the model.To dynamically compare results from different models, the relation between the definition of Knudsen number in hard sphere model and that in BGK model is clarified.
基金Supported by National Natural Science Foundation of China under Grant Nos.11772064,and 11502117CAEP Foundation under Grant No.CX2019033+1 种基金the opening project of State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology)Science Challenge Project under Grant No.JCKY2016212A501
文摘A one-dimensional discrete Boltzmann model for detonation simulation is presented. Instead of numerical solving Navier-Stokes equations, this model obtains the information of flow field through numerical solving specially discretized Boltzmann equation. Several classical benchmarks including Sod shock wave tube, Colella explosion problem,and one-dimensional self-sustainable stable detonation are simulated to validate the new model. Based on the new model,the influence of negative temperature coefficient of reaction rate on detonation is further investigated. It is found that an abnormal detonation with two wave heads periodically appears under negative temperature coefficient condition.The causes of the abnormal detonation are analyzed. One typical cycle of the periodic abnormal detonation and its development process are discussed.
基金supported by the National Natural Science Foundation of China (No. 61170318)the Natural Science Foundation of Shanghai (No. 11ZR1409600)+1 种基金the National S&T Major Project of China (No. 2011ZX09307-002-03)the Open Research Funding Program of KLGIS (No. KLGIS2011A06)
文摘Emergency exercises are an efficient approach for preventing serious damage and harm, including loss of life and property and a wide range of adverse social effects, during various public emergencies. Among various factors affecting the value of emergency exercises, including their design, development, conduct, evaluation, and improvement planning, this paper emphasizes the focal role of evacuees and their behavior. We address two concerns: What are the intrinsic reasons behind human behavior? How do we model and exhibit human behavior? We review studies investigating the mechanisms of psychological behavior and crowd evacuation animation. A comprehensive analysis of logical patterns of behavior and crowd evacuation is presented first. The interactive effects of information (objective and subjective), psychology (panic, small groups, and conflicting roles), and six kinds of behavior contribute to a more effective understanding of an emergency scene and assist in making scientific decisions. Based on these studies, a wide range of perspectives on crowd formation and evacuation animation models is summa- rized. Collision avoidance is underlined as a special topic. Finally, this paper highlights some of the technical challenges and key questions to be addressed by future developments in this rapidly developing field.
基金Project supported by the National Basic Research Program (973) of China (No.2011CB302203)the Innovation Program of the Science and Technology Commission of Shanghai Municipality,China (No.10511501200)
文摘We synthesize animations from a single image by transferring fluid motion of a video example globally.Given a target image of a fluid scene,an alpha matte is required to extract the fluid region.Our method needs to adjust a user-specified video example for producing the fluid motion suitable for the extracted fluid region.Employing the fluid video database,the flow field of the target image is obtained by warping the optical flow of a video frame that has a visually similar scene to the target image according to their scene correspondences,which assigns fluid orientation and speed automatically.Results show that our method is successful in preserving large fluid features in the synthesized animations.In comparison to existing approaches,it is both possible and useful to utilize our method to create flow animations with higher quality.
基金Project supported by the Program for New Century Excel-lent Talents in University (No. NCET-08-0450)the 985 II of Xi’an Jiaotong University, and the High Talented Person Scientific Research Start Project of North China University of Water Resources and Electric Power (No. 003001)
文摘Flattening of the interfaces is necessary in computing wave propagation along strati?ed waveguides in large range step sizes while using marching methods. When the supposition that there exists one horizontal straight line in two adjacent interfaces does not hold, the previously suggested local orthogonal transform method with an analytical formulation is not feasible. This paper presents a numerical coordinate transform and an equation transform to perform the transforms numerically for waveguides without satisfying the supposition. The boundary value problem is then reduced to an initial value problem by one-way reformulation based on the Dirichlet-to-Neumann (DtN) map. This method is applicable in solving long-range wave propagation problems in slowly varying waveguides with a multilayered medium structure.