ZnO is a highly significant II-VI semiconductor known for its excellent optoelectronic properties,making it widely applicable and promising for use in light-emitting devices,solar cells,lasers,and photodetectors.The m...ZnO is a highly significant II-VI semiconductor known for its excellent optoelectronic properties,making it widely applicable and promising for use in light-emitting devices,solar cells,lasers,and photodetectors.The methods for preparing ZnO are diverse,and among them,the hydrothermal method is favored for its simplicity,ease of operation,and low cost,making it an optimal choice for ZnO single-crystal growth.Most studies investigating the effects of different hydrothermal experimental parameters on the morphology and performance of ZnO nano-materials typically focus on only 2—3 variable parameters,with few examining the impact of all possible experimental parameter changes on ZnO nano-mate-rials.The principles of the hydrothermal method and its advantages in nano-material preparation were briefly introduced in this article.The detailed discussion on the influence of various experimental parameters on the preparation of ZnO nano-materials was provided,which including reaction materials,Zn^(2+)/OH^(-)ratio,reaction time and temperature,additives,experimental equipment,and annealing conditions.The review co-vers how different experimental parameters affect the morphology and performance of the materials,as well as how different rare earth doping elements influence the performance of ZnO nano-materials.It is hoped that this work will contribute to future research on the hydrothermal synthesis of nano-materials.展开更多
Federated learning(FL)is a distributed machine learning paradigm for edge cloud computing.FL can facilitate data-driven decision-making in tactical scenarios,effectively addressing both data volume and infrastructure ...Federated learning(FL)is a distributed machine learning paradigm for edge cloud computing.FL can facilitate data-driven decision-making in tactical scenarios,effectively addressing both data volume and infrastructure challenges in edge environments.However,the diversity of clients in edge cloud computing presents significant challenges for FL.Personalized federated learning(pFL)received considerable attention in recent years.One example of pFL involves exploiting the global and local information in the local model.Current pFL algorithms experience limitations such as slow convergence speed,catastrophic forgetting,and poor performance in complex tasks,which still have significant shortcomings compared to the centralized learning.To achieve high pFL performance,we propose FedCLCC:Federated Contrastive Learning and Conditional Computing.The core of FedCLCC is the use of contrastive learning and conditional computing.Contrastive learning determines the feature representation similarity to adjust the local model.Conditional computing separates the global and local information and feeds it to their corresponding heads for global and local handling.Our comprehensive experiments demonstrate that FedCLCC outperforms other state-of-the-art FL algorithms.展开更多
A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment ...A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment effect and interim result.For hypotheses and reversed hypotheses under normal models,we obtain analytical expressions of the ROC curves of the CCP,find optimal ROC curves of the CCP,investigate the superiority of the ROC curves of the CCP,calculate critical values of the False Positive Rate(FPR),True Positive Rate(TPR),and cutoff of the optimal CCP,and give go/no go decisions at the interim of the optimal CCP.In addition,extensive numerical experiments are carried out to exemplify our theoretical results.Finally,a real data example is performed to illustrate the go/no go decisions of the optimal CCP.展开更多
Finding sustainable energy resources is essential to face the increasing energy demand.Trees are an important part of ancient architecture but are becoming rare in urban areas.Trees can control and tune the pedestrian...Finding sustainable energy resources is essential to face the increasing energy demand.Trees are an important part of ancient architecture but are becoming rare in urban areas.Trees can control and tune the pedestrian-level wind velocity and thermal condition.In this study,a numerical investigation is employed to assess the role of trees planted in the windward direction of the building complex on the thermal and pedestrian wind velocity conditions around/inside a pre-education building located in the center of the complex.Compared to the previous studies(which considered only outside buildings),this work considers the effects of trees on microclimate change both inside/outside buildings.Effects of different parameters including the leaf area density and number of trees,number of rows,far-field velocity magnitude,and thermal condition around the main building are assessed.The results show that the flow velocity in the spacing between the first-row buildings is reduced by 30%-40% when the one-row trees with 2 m height are planted 15 m farther than the buildings.Furthermore,two rows of trees are more effective in higher velocities and reduce the maximum velocity by about 50%.The investigation shows that trees also could reduce the temperature by about 1℃around the building.展开更多
Solder joint,crucial component in electronic systems,face significant challenges when exposed to extreme conditions during applications.The solder joint reliability involving microstructure and mechanical properties w...Solder joint,crucial component in electronic systems,face significant challenges when exposed to extreme conditions during applications.The solder joint reliability involving microstructure and mechanical properties will be affected by extreme conditions.Understanding the behaviour of solder joints under extreme conditions is vital to determine the durability and reliability of solder joint.This review paper aims to comprehensively explore the underlying failure mechanism affecting solder joint reliability under extreme conditions.This study covers an in-depth analysis of effect extreme temperature,mechanical stress,and radiation conditions towards solder joint.Impact of each condition to the microstructure including solder matrix and intermetallic compound layer,and mechanical properties such as fatigue,shear strength,creep,and hardness was thoroughly discussed.The failure mechanisms were illustrated in graphical diagrams to ensure clarity and understanding.Furthermore,the paper highlighted mitigation strategies that enhancing solder joint reliability under challenging operating conditions.The findings offer valuable guidance for researchers,engineers,and practitioners involved in electronics,engineering,and related fields,fostering advancements in solder joint reliability and performance.展开更多
Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enh...Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enhance the performance of guided wave damage detection in noisy environments is crucial.This paper introduces a local temporal principal component analysis(PCA)reconstruction approach for denoising guided waves prior to implementing unsupervised damage detection,achieved through novel autoencoder-based reconstruction.Experimental results demonstrate that the proposed denoising method significantly enhances damage detection performance when guided waves are contaminated by noise,with SNR values ranging from 10 to-5 dB.Following the implementation of the proposed denoising approach,the AUC score can elevate from 0.65 to 0.96 when dealing with guided waves corrputed by noise at a level of-5 dB.Additionally,the paper provides guidance on selecting the appropriate number of components used in the denoising PCA reconstruction,aiding in the optimization of the damage detection in noisy conditions.展开更多
In this paper,we introduce the censored composite conditional quantile coefficient(cC-CQC)to rank the relative importance of each predictor in high-dimensional censored regression.The cCCQC takes advantage of all usef...In this paper,we introduce the censored composite conditional quantile coefficient(cC-CQC)to rank the relative importance of each predictor in high-dimensional censored regression.The cCCQC takes advantage of all useful information across quantiles and can detect nonlinear effects including interactions and heterogeneity,effectively.Furthermore,the proposed screening method based on cCCQC is robust to the existence of outliers and enjoys the sure screening property.Simulation results demonstrate that the proposed method performs competitively on survival datasets of high-dimensional predictors,particularly when the variables are highly correlated.展开更多
This article generally studies American workers’ economic conditions in the late nineteenth century. Through the examination of their poor living conditions, the author aims to expose the dark side of America in the ...This article generally studies American workers’ economic conditions in the late nineteenth century. Through the examination of their poor living conditions, the author aims to expose the dark side of America in the period of Industrialization.展开更多
In the experiment, the brown rice whose moisture content was 12.5% was used as raw material. The brown rice was grouped, then moisturized differently and milled. While milling, the energy consumption, the rate of brok...In the experiment, the brown rice whose moisture content was 12.5% was used as raw material. The brown rice was grouped, then moisturized differently and milled. While milling, the energy consumption, the rate of broken rice and the crack rate were tested. It is confirmed that the stress crack owing to the moisture added to the brown rice can be avoided when the moisture amount added once is limited to no more than 1.5%. It is also proved that the energy consumption can be reduced, the yielding rate of rice can be increased and that the quality of rice can be improved.展开更多
Iron sulfide minerals are widely distributed, of which characteristics had the identification significance of formation environment. Previously, there were more research on iron sulfide minerals under hydrothermal con...Iron sulfide minerals are widely distributed, of which characteristics had the identification significance of formation environment. Previously, there were more research on iron sulfide minerals under hydrothermal condition, and few studies under volcanism formation condition. To simulate volcanic mineralization, the study of different temperature from 250 to 410℃ , different iron sulfur ratio from Fe:S=2∶1 to 1∶8, and two different sources of iron, reduced iron powder (Fe) and ferrous sulfide (FeS), on iron sulfide mineral evolution was investigated under thermal sulfurization condition. By using scanning electron microscopy (SEM), X-ray diffraction (XRD) and other methods, the morphology, composition and structural characteristics of the products were observed and analyzed.展开更多
This paper analyzes the performance of the orthogonal matching pursuit （OMP） algorithm in recovering sparse signals from noisy measurement. Considering the fact that some matrices satisfy some restricted isometry pr...This paper analyzes the performance of the orthogonal matching pursuit （OMP） algorithm in recovering sparse signals from noisy measurement. Considering the fact that some matrices satisfy some restricted isometry properties （RIPs） but not the coherence condition, a superior RIP-based condition is proposed, which means that if the measurement matrix satisfies δk＋1 〈 1/（2 ＋ √k） and the minimum component signal-to-noise ratio （MCSNR） is bounded, the OMP algorithm can exactly identify the support of the original sparse signal within k iterations. Finally, the theoretical results are verified by numerical simulations con- cerning different values of MCSNR and noise levels.展开更多
Boundary conditions for the classical solution of the Terzaghi one-dimensional consolidation equation conflict with the equation＇s initial condition. As such, the classical initial-boundary value problem for the Terz...Boundary conditions for the classical solution of the Terzaghi one-dimensional consolidation equation conflict with the equation＇s initial condition. As such, the classical initial-boundary value problem for the Terzaghi one-dimensional consolidation equation is not well-posed. Moreover, the classical boundary conditions of the equation can only be applied to problems with either perfectly pervious or perfectly impervious boundaries. General boundary conditions are proposed to overcome these shortcomings and thus transfer the solution of the Terzaghi one-dimensional consolidation equation to a well-posed initial boundary value problem. The solution for proposed general boundary conditions is validated by comparing it to the classical solution. The actual field drainage conditions can be simulated by adjusting the values of parameters b and c given in the proposed general botmdary conditions. For relatively high coefficient of consolidation, just one term in series expansions is enough to obtain results with acceptable accuracy.展开更多
The objective of this work is to develop a novel feature for traffic flow models, when traffic queues on two-way arterials periodically extend until then they block an upstream signal in oversaturated conditions. The ...The objective of this work is to develop a novel feature for traffic flow models, when traffic queues on two-way arterials periodically extend until then they block an upstream signal in oversaturated conditions. The new model, proposed as conditional cell transmission model （CCTM） has been developed with two improvements. First, cell transmission model （CTM） is expanded for two-way arterials by taking account of all diverging and merging activities at intersections. Second, a conditional cell is added to simulate periodic spillback and blockages at an intersection. The results of experiments for a multilane, two-way, three-signal sample network demonstrate that CCTM can accommodate various traffic demands and accurate representation of blockages at intersections. The delay of left turns is underestimated by 40 % in moderate conditions and by 58% in oversamrated condition when using the CTM rather than CCTM. Finally, the consistency between HCS 2000 and CCTM shows that CCTM is a reliable methodology of modeling traffic flow in oversaturated condition.展开更多
In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,...In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,the rheological tests were carried out.These experiment results showed that the stress conditions,especially the stress level were the critical influencing factors of the rheological deformation properties.Under the low stress level(S=0.1),the granular soil showed the elastic properties,and there was no obvious rheological deformation.Under the middle stress level(0.2<S≤0.6),creep curves showed the linear viscoelastic rheological properties.However,under the high stress level(S>0.8) creep curves showed the non-linear viscous plastic rheological properties.Especially,under the stress level of S=1.0,the accelerated rheological phase of creep curves occurred at early time with a trend of failure.The stress level had obvious effects on the final rheological deformation of the soil sample,and the final rheological deformation increments nonlinearly increased with stress level.The final rheological deformation increment and step was little under low stress level,while it became large under high stress level,which showed the nonlinearly rheological properties of the granular soil.The confining pressure also had direct effects on final rheological deformation,and the final rheological deformation linearly increased with confining pressure increments.展开更多
Rock bolts are widely used in rock engineering projects to improve the shear capacity of the jointed rock mass.The bolt inclination angle with respect to the shear plane has a remarkable influence on the bolting perfo...Rock bolts are widely used in rock engineering projects to improve the shear capacity of the jointed rock mass.The bolt inclination angle with respect to the shear plane has a remarkable influence on the bolting performance.In this study,a new artificial molding method based on 3D scanning and printing technology was first proposed to prepare bolted joints with an inclined bolt.Then,the effects of the bolt inclination angle and boundary conditions on the shear behavior and failure characteristic of bolted joints were addressed by conducting direct shear tests under both CNL and CNS conditions.Results indicated that rock bolt could significantly improve the shear behavior of rock joints,especially in the post-yield deformation region.With the increase of bolt inclination angle,both the maximum shear stress and the maximum friction coefficient increased first and then decreased,while the maximum normal displacement decreased monotonously.Compared with CNL conditions,the maximum shear stress was larger,whereas the maximum normal displacement and friction coefficient were smaller under the CNS conditions.Furthermore,more asperity damage was observed under the CNS conditions due to the increased normal stress on the shear plane.展开更多
Infrared false target is an important mean to induce the infrared-guided weapons,and the key issue is how to keep the surface temperature of the infrared false target to be the same as that of the object to be protect...Infrared false target is an important mean to induce the infrared-guided weapons,and the key issue is how to keep the surface temperature of the infrared false target to be the same as that of the object to be protected.One-dimensional heat transfer models of a metal plate and imitative material were established to explore the influences of the thermophysical properties of imitative material on the surface temperature difference（STD） between the metal plate and imitative material which were subjected to periodical ambient conditions.It is elucidated that the STD is determined by the imitative material’s dimensionless thickness（dim*,） and the thermal inertia(Pim).When dim* is above 1.0,the STD is invariable as long as Pim is a constant.And if the dimensionless thickness of metal plate（d,m*） is also larger than 1.0,the STD approaches to zero as long as Pimis the same as the thermal inertia of metal plate（Pm）.When dim* is between 0.08 and 1,the STD varies irregularly with Pim and dim*.However,if dm* is also in the range of 0.08-1,the STD approaches to zero on condition that Pim=Pm and dim*= dm*.If dim*,is below 0.08,the STD is unchanged when Pimdim* is a constant.And if dm* is also less than 0.08,the STD approaches to zero as long as Pimdim* = Pmdm*.Furthermore,an applicationoriented discussion indicates that the imitative material can be both light and thin via the application of the phase change material with a preset STD because of its high specific heat capacity during the phase transition process.展开更多
The condition of weightes non-dictatorship is extended and a comprehensive evaluae method emboding self-determinate which is combined with competitive view optimization principles is built. The basic process includes ...The condition of weightes non-dictatorship is extended and a comprehensive evaluae method emboding self-determinate which is combined with competitive view optimization principles is built. The basic process includes simulating the model of economic man＇s self-benefit bahaviors, taking the place of experts to evaluate, bringing in the model of minimizing the sum of included angles to integrate the information of multiple objects and put the objects in order finally. The method has the advangtages of less dependendence on the subjective information, plenty of information, fair process and simple caculating. Finally, an application example is given to illustrate the effectiveness of the proposed method.展开更多
A pre-selection space time model was proposed to estimate the traffic condition at poor-data-detector,especially non-detector locations.The space time model is better to integrate the spatial and temporal information ...A pre-selection space time model was proposed to estimate the traffic condition at poor-data-detector,especially non-detector locations.The space time model is better to integrate the spatial and temporal information comprehensibly.Firstly,the influencing factors of the "cause nodes" were studied,and then the pre-selection "cause nodes" procedure which utilizes the Pearson correlation coefficient to evaluate the relevancy of the traffic data was introduced.Finally,only the most relevant data were collected to compose the space time model.The experimental results with the actual data demonstrate that the model performs better than other three models.展开更多
Thermal safety of modular charge which is fed into and retained in the chamber after gun fires consecutively is first investigated with cook-off method,A two-dimensional cook-off model of modular charge in gun chamber...Thermal safety of modular charge which is fed into and retained in the chamber after gun fires consecutively is first investigated with cook-off method,A two-dimensional cook-off model of modular charge in gun chamber is established and the cook-off process of modular charge in gun chamber is numerically simulated.Then the effects of module number and firing condition on charge thermal safety are evaluated by researching the cook-off response characteristics of modules.The results show that under conditions of different module numbers the cook-off responses all occur on the module closest to the boundary of missile,and the single-base propellants located at the inner surface of cartridge ignite first.When the number of loaded module changes from 1 to 6,the cook-off response temperatures vary little,only in a small range of 478.1 K-482.4 K.The cook-off response times decrease logarithmically in the range of 211.25-166.7 s with the increasing length of residual air gap in gun chamber.The simulation results are well matched with the experimental data.Furthermore,different firing conditions have greatinfluence on the cook-off response time,minor influence on the initial response position and little in-fluence on the response temperature.Under the three conditions of consecutive 32 launches with 5 rounds/min,43 launches with 1 round/min,and 41 launches with different firing frequencies,the cook off response temperatures are 479.2 K,481.1 K and 479.9 K respectively and the response times are 709.25,211.2 s and 214.4 s respectively.The response position is near the middle area of the inner cartridge surface in the former condition and near the right area in the latter two conditions.展开更多
文摘ZnO is a highly significant II-VI semiconductor known for its excellent optoelectronic properties,making it widely applicable and promising for use in light-emitting devices,solar cells,lasers,and photodetectors.The methods for preparing ZnO are diverse,and among them,the hydrothermal method is favored for its simplicity,ease of operation,and low cost,making it an optimal choice for ZnO single-crystal growth.Most studies investigating the effects of different hydrothermal experimental parameters on the morphology and performance of ZnO nano-materials typically focus on only 2—3 variable parameters,with few examining the impact of all possible experimental parameter changes on ZnO nano-mate-rials.The principles of the hydrothermal method and its advantages in nano-material preparation were briefly introduced in this article.The detailed discussion on the influence of various experimental parameters on the preparation of ZnO nano-materials was provided,which including reaction materials,Zn^(2+)/OH^(-)ratio,reaction time and temperature,additives,experimental equipment,and annealing conditions.The review co-vers how different experimental parameters affect the morphology and performance of the materials,as well as how different rare earth doping elements influence the performance of ZnO nano-materials.It is hoped that this work will contribute to future research on the hydrothermal synthesis of nano-materials.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(Grant No.2022D01B 187)。
文摘Federated learning(FL)is a distributed machine learning paradigm for edge cloud computing.FL can facilitate data-driven decision-making in tactical scenarios,effectively addressing both data volume and infrastructure challenges in edge environments.However,the diversity of clients in edge cloud computing presents significant challenges for FL.Personalized federated learning(pFL)received considerable attention in recent years.One example of pFL involves exploiting the global and local information in the local model.Current pFL algorithms experience limitations such as slow convergence speed,catastrophic forgetting,and poor performance in complex tasks,which still have significant shortcomings compared to the centralized learning.To achieve high pFL performance,we propose FedCLCC:Federated Contrastive Learning and Conditional Computing.The core of FedCLCC is the use of contrastive learning and conditional computing.Contrastive learning determines the feature representation similarity to adjust the local model.Conditional computing separates the global and local information and feeds it to their corresponding heads for global and local handling.Our comprehensive experiments demonstrate that FedCLCC outperforms other state-of-the-art FL algorithms.
基金supported by the National Social Science Fund of China(Grand No.21XTJ001).
文摘A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment effect and interim result.For hypotheses and reversed hypotheses under normal models,we obtain analytical expressions of the ROC curves of the CCP,find optimal ROC curves of the CCP,investigate the superiority of the ROC curves of the CCP,calculate critical values of the False Positive Rate(FPR),True Positive Rate(TPR),and cutoff of the optimal CCP,and give go/no go decisions at the interim of the optimal CCP.In addition,extensive numerical experiments are carried out to exemplify our theoretical results.Finally,a real data example is performed to illustrate the go/no go decisions of the optimal CCP.
文摘Finding sustainable energy resources is essential to face the increasing energy demand.Trees are an important part of ancient architecture but are becoming rare in urban areas.Trees can control and tune the pedestrian-level wind velocity and thermal condition.In this study,a numerical investigation is employed to assess the role of trees planted in the windward direction of the building complex on the thermal and pedestrian wind velocity conditions around/inside a pre-education building located in the center of the complex.Compared to the previous studies(which considered only outside buildings),this work considers the effects of trees on microclimate change both inside/outside buildings.Effects of different parameters including the leaf area density and number of trees,number of rows,far-field velocity magnitude,and thermal condition around the main building are assessed.The results show that the flow velocity in the spacing between the first-row buildings is reduced by 30%-40% when the one-row trees with 2 m height are planted 15 m farther than the buildings.Furthermore,two rows of trees are more effective in higher velocities and reduce the maximum velocity by about 50%.The investigation shows that trees also could reduce the temperature by about 1℃around the building.
基金fully supported by a Tabung Amanah Pusat Pengurusan Penyelidikan&Inovasi(PPPI)(Grant No.PS060-UPNM/2023/GPPP/SG/1)Universiti Pertahanan Nasional Malaysia(UPNM)for funding this study。
文摘Solder joint,crucial component in electronic systems,face significant challenges when exposed to extreme conditions during applications.The solder joint reliability involving microstructure and mechanical properties will be affected by extreme conditions.Understanding the behaviour of solder joints under extreme conditions is vital to determine the durability and reliability of solder joint.This review paper aims to comprehensively explore the underlying failure mechanism affecting solder joint reliability under extreme conditions.This study covers an in-depth analysis of effect extreme temperature,mechanical stress,and radiation conditions towards solder joint.Impact of each condition to the microstructure including solder matrix and intermetallic compound layer,and mechanical properties such as fatigue,shear strength,creep,and hardness was thoroughly discussed.The failure mechanisms were illustrated in graphical diagrams to ensure clarity and understanding.Furthermore,the paper highlighted mitigation strategies that enhancing solder joint reliability under challenging operating conditions.The findings offer valuable guidance for researchers,engineers,and practitioners involved in electronics,engineering,and related fields,fostering advancements in solder joint reliability and performance.
基金National Science Foundation of Zhejiang under Contract(LY23E010001)。
文摘Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enhance the performance of guided wave damage detection in noisy environments is crucial.This paper introduces a local temporal principal component analysis(PCA)reconstruction approach for denoising guided waves prior to implementing unsupervised damage detection,achieved through novel autoencoder-based reconstruction.Experimental results demonstrate that the proposed denoising method significantly enhances damage detection performance when guided waves are contaminated by noise,with SNR values ranging from 10 to-5 dB.Following the implementation of the proposed denoising approach,the AUC score can elevate from 0.65 to 0.96 when dealing with guided waves corrputed by noise at a level of-5 dB.Additionally,the paper provides guidance on selecting the appropriate number of components used in the denoising PCA reconstruction,aiding in the optimization of the damage detection in noisy conditions.
基金Outstanding Youth Foundation of Hunan Provincial Department of Education(Grant No.22B0911)。
文摘In this paper,we introduce the censored composite conditional quantile coefficient(cC-CQC)to rank the relative importance of each predictor in high-dimensional censored regression.The cCCQC takes advantage of all useful information across quantiles and can detect nonlinear effects including interactions and heterogeneity,effectively.Furthermore,the proposed screening method based on cCCQC is robust to the existence of outliers and enjoys the sure screening property.Simulation results demonstrate that the proposed method performs competitively on survival datasets of high-dimensional predictors,particularly when the variables are highly correlated.
文摘This article generally studies American workers’ economic conditions in the late nineteenth century. Through the examination of their poor living conditions, the author aims to expose the dark side of America in the period of Industrialization.
基金Tenth Eive-Year Plan of the Committee of the Scientific Tech. of Heilongjiang Province (GB02B4040-1)Heilongjiang Education Bureau (10511012)
文摘In the experiment, the brown rice whose moisture content was 12.5% was used as raw material. The brown rice was grouped, then moisturized differently and milled. While milling, the energy consumption, the rate of broken rice and the crack rate were tested. It is confirmed that the stress crack owing to the moisture added to the brown rice can be avoided when the moisture amount added once is limited to no more than 1.5%. It is also proved that the energy consumption can be reduced, the yielding rate of rice can be increased and that the quality of rice can be improved.
基金Supported by National Natural Science Foundation (Grant No.:40872045 41172047)The Opening Project of Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education (12zxgk01)
文摘Iron sulfide minerals are widely distributed, of which characteristics had the identification significance of formation environment. Previously, there were more research on iron sulfide minerals under hydrothermal condition, and few studies under volcanism formation condition. To simulate volcanic mineralization, the study of different temperature from 250 to 410℃ , different iron sulfur ratio from Fe:S=2∶1 to 1∶8, and two different sources of iron, reduced iron powder (Fe) and ferrous sulfide (FeS), on iron sulfide mineral evolution was investigated under thermal sulfurization condition. By using scanning electron microscopy (SEM), X-ray diffraction (XRD) and other methods, the morphology, composition and structural characteristics of the products were observed and analyzed.
基金supported by the National Natural Science Foundation of China(6117401661171197)
文摘This paper analyzes the performance of the orthogonal matching pursuit （OMP） algorithm in recovering sparse signals from noisy measurement. Considering the fact that some matrices satisfy some restricted isometry properties （RIPs） but not the coherence condition, a superior RIP-based condition is proposed, which means that if the measurement matrix satisfies δk＋1 〈 1/（2 ＋ √k） and the minimum component signal-to-noise ratio （MCSNR） is bounded, the OMP algorithm can exactly identify the support of the original sparse signal within k iterations. Finally, the theoretical results are verified by numerical simulations con- cerning different values of MCSNR and noise levels.
基金Foundation item： Project（50608038） supported by the National Natural Science Foundation of China
文摘Boundary conditions for the classical solution of the Terzaghi one-dimensional consolidation equation conflict with the equation＇s initial condition. As such, the classical initial-boundary value problem for the Terzaghi one-dimensional consolidation equation is not well-posed. Moreover, the classical boundary conditions of the equation can only be applied to problems with either perfectly pervious or perfectly impervious boundaries. General boundary conditions are proposed to overcome these shortcomings and thus transfer the solution of the Terzaghi one-dimensional consolidation equation to a well-posed initial boundary value problem. The solution for proposed general boundary conditions is validated by comparing it to the classical solution. The actual field drainage conditions can be simulated by adjusting the values of parameters b and c given in the proposed general botmdary conditions. For relatively high coefficient of consolidation, just one term in series expansions is enough to obtain results with acceptable accuracy.
基金Project(51108343) supported by the National Natural Science Foundation of ChinaProject(06121) supported by University of Transportation Center for Alabama,USA
文摘The objective of this work is to develop a novel feature for traffic flow models, when traffic queues on two-way arterials periodically extend until then they block an upstream signal in oversaturated conditions. The new model, proposed as conditional cell transmission model （CCTM） has been developed with two improvements. First, cell transmission model （CTM） is expanded for two-way arterials by taking account of all diverging and merging activities at intersections. Second, a conditional cell is added to simulate periodic spillback and blockages at an intersection. The results of experiments for a multilane, two-way, three-signal sample network demonstrate that CCTM can accommodate various traffic demands and accurate representation of blockages at intersections. The delay of left turns is underestimated by 40 % in moderate conditions and by 58% in oversamrated condition when using the CTM rather than CCTM. Finally, the consistency between HCS 2000 and CCTM shows that CCTM is a reliable methodology of modeling traffic flow in oversaturated condition.
基金Project(200413) supported by Communication Science and Technology Fund of Hunan Province,China
文摘In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,the rheological tests were carried out.These experiment results showed that the stress conditions,especially the stress level were the critical influencing factors of the rheological deformation properties.Under the low stress level(S=0.1),the granular soil showed the elastic properties,and there was no obvious rheological deformation.Under the middle stress level(0.2<S≤0.6),creep curves showed the linear viscoelastic rheological properties.However,under the high stress level(S>0.8) creep curves showed the non-linear viscous plastic rheological properties.Especially,under the stress level of S=1.0,the accelerated rheological phase of creep curves occurred at early time with a trend of failure.The stress level had obvious effects on the final rheological deformation of the soil sample,and the final rheological deformation increments nonlinearly increased with stress level.The final rheological deformation increment and step was little under low stress level,while it became large under high stress level,which showed the nonlinearly rheological properties of the granular soil.The confining pressure also had direct effects on final rheological deformation,and the final rheological deformation linearly increased with confining pressure increments.
基金Project(U1865203)supported by the Key Projects of the Yalong River Joint Fund of the National Natural Science Foundation of ChinaProject(51279201)supported by the National Natural Science Foundation of ChinaProjects(2019YFC0605103,2019YFC0605100)supported by the National Key R&D Program of China。
文摘Rock bolts are widely used in rock engineering projects to improve the shear capacity of the jointed rock mass.The bolt inclination angle with respect to the shear plane has a remarkable influence on the bolting performance.In this study,a new artificial molding method based on 3D scanning and printing technology was first proposed to prepare bolted joints with an inclined bolt.Then,the effects of the bolt inclination angle and boundary conditions on the shear behavior and failure characteristic of bolted joints were addressed by conducting direct shear tests under both CNL and CNS conditions.Results indicated that rock bolt could significantly improve the shear behavior of rock joints,especially in the post-yield deformation region.With the increase of bolt inclination angle,both the maximum shear stress and the maximum friction coefficient increased first and then decreased,while the maximum normal displacement decreased monotonously.Compared with CNL conditions,the maximum shear stress was larger,whereas the maximum normal displacement and friction coefficient were smaller under the CNS conditions.Furthermore,more asperity damage was observed under the CNS conditions due to the increased normal stress on the shear plane.
基金funded by the National Natural Science Foundation of China (No. 51576188)
文摘Infrared false target is an important mean to induce the infrared-guided weapons,and the key issue is how to keep the surface temperature of the infrared false target to be the same as that of the object to be protected.One-dimensional heat transfer models of a metal plate and imitative material were established to explore the influences of the thermophysical properties of imitative material on the surface temperature difference（STD） between the metal plate and imitative material which were subjected to periodical ambient conditions.It is elucidated that the STD is determined by the imitative material’s dimensionless thickness（dim*,） and the thermal inertia(Pim).When dim* is above 1.0,the STD is invariable as long as Pim is a constant.And if the dimensionless thickness of metal plate（d,m*） is also larger than 1.0,the STD approaches to zero as long as Pimis the same as the thermal inertia of metal plate（Pm）.When dim* is between 0.08 and 1,the STD varies irregularly with Pim and dim*.However,if dm* is also in the range of 0.08-1,the STD approaches to zero on condition that Pim=Pm and dim*= dm*.If dim*,is below 0.08,the STD is unchanged when Pimdim* is a constant.And if dm* is also less than 0.08,the STD approaches to zero as long as Pimdim* = Pmdm*.Furthermore,an applicationoriented discussion indicates that the imitative material can be both light and thin via the application of the phase change material with a preset STD because of its high specific heat capacity during the phase transition process.
基金supported by the National Natural Science Foundation of China(70801013)LNSTF for doc-tor(20081020).
文摘The condition of weightes non-dictatorship is extended and a comprehensive evaluae method emboding self-determinate which is combined with competitive view optimization principles is built. The basic process includes simulating the model of economic man＇s self-benefit bahaviors, taking the place of experts to evaluate, bringing in the model of minimizing the sum of included angles to integrate the information of multiple objects and put the objects in order finally. The method has the advangtages of less dependendence on the subjective information, plenty of information, fair process and simple caculating. Finally, an application example is given to illustrate the effectiveness of the proposed method.
基金Project(D101106049710005) supported by the Beijing Science Foundation Program,ChinaProject(61104164) supported by the National Natural Science Foundation,China
文摘A pre-selection space time model was proposed to estimate the traffic condition at poor-data-detector,especially non-detector locations.The space time model is better to integrate the spatial and temporal information comprehensibly.Firstly,the influencing factors of the "cause nodes" were studied,and then the pre-selection "cause nodes" procedure which utilizes the Pearson correlation coefficient to evaluate the relevancy of the traffic data was introduced.Finally,only the most relevant data were collected to compose the space time model.The experimental results with the actual data demonstrate that the model performs better than other three models.
文摘Thermal safety of modular charge which is fed into and retained in the chamber after gun fires consecutively is first investigated with cook-off method,A two-dimensional cook-off model of modular charge in gun chamber is established and the cook-off process of modular charge in gun chamber is numerically simulated.Then the effects of module number and firing condition on charge thermal safety are evaluated by researching the cook-off response characteristics of modules.The results show that under conditions of different module numbers the cook-off responses all occur on the module closest to the boundary of missile,and the single-base propellants located at the inner surface of cartridge ignite first.When the number of loaded module changes from 1 to 6,the cook-off response temperatures vary little,only in a small range of 478.1 K-482.4 K.The cook-off response times decrease logarithmically in the range of 211.25-166.7 s with the increasing length of residual air gap in gun chamber.The simulation results are well matched with the experimental data.Furthermore,different firing conditions have greatinfluence on the cook-off response time,minor influence on the initial response position and little in-fluence on the response temperature.Under the three conditions of consecutive 32 launches with 5 rounds/min,43 launches with 1 round/min,and 41 launches with different firing frequencies,the cook off response temperatures are 479.2 K,481.1 K and 479.9 K respectively and the response times are 709.25,211.2 s and 214.4 s respectively.The response position is near the middle area of the inner cartridge surface in the former condition and near the right area in the latter two conditions.
