Within the roadway advanced detection methods, DC resistivity method has an extensive application because of its simple principle and operation. Numerical simulation of the effect of focusing current on advanced detec...Within the roadway advanced detection methods, DC resistivity method has an extensive application because of its simple principle and operation. Numerical simulation of the effect of focusing current on advanced detection was carried out using a three-dimensional finite element method （FEM）, meanwhile the electric-field distribution of the point source and nine-point power source were calculated and analyzed with the same electric charges. The results show that the nine-point power source array has a very good ability to focus, and the DC focus method can be used to predict the aquifer abnormality body precisely. By comparing the FEM modelling results with physical simulation results from soil sink, it is shown that the accuracy of forward simulation meets the requirement and the artificial disturbance from roadway has no impact on the DC focus method.展开更多
To reasonably implement the reliability analysis and describe the significance of influencing parameters for the multi-failure modes of turbine blisk, advanced multiple response surface method (AMRSM) was proposed for...To reasonably implement the reliability analysis and describe the significance of influencing parameters for the multi-failure modes of turbine blisk, advanced multiple response surface method (AMRSM) was proposed for multi-failure mode sensitivity analysis for reliability. The mathematical model of AMRSM was established and the basic principle of multi-failure mode sensitivity analysis for reliability with AMRSM was given. The important parameters of turbine blisk failures are obtained by the multi-failure mode sensitivity analysis of turbine blisk. Through the reliability sensitivity analyses of multiple failure modes (deformation, stress and strain) with the proposed method considering fluid-thermal-solid interaction, it is shown that the comprehensive reliability of turbine blisk is 0.9931 when the allowable deformation, stress and strain are 3.7 x 10(-3) m, 1.0023 x 10(9) Pa and 1.05 x 10(-2) m/m, respectively; the main impact factors of turbine blisk failure are gas velocity, gas temperature and rotational speed. As demonstrated in the comparison of methods (Monte Carlo (MC) method, traditional response surface method (RSM), multiple response surface method (MRSM) and AMRSM), the proposed AMRSM improves computational efficiency with acceptable computational accuracy. The efforts of this study provide the AMRSM with high precision and efficiency for multi-failure mode reliability analysis, and offer a useful insight for the reliability optimization design of multi-failure mode structure. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.展开更多
Tunneling machines, or excavators, are large and good conductors and affect the reliability of data gathering and interpretation in advanced detection using transient electromagnetic methods. In our experiment, we use...Tunneling machines, or excavators, are large and good conductors and affect the reliability of data gathering and interpretation in advanced detection using transient electromagnetic methods. In our experiment, we used a coincident-loop and central loop type of configuration, where the coil plane l） vertical to and 2） parallel to the working face. A SIROTEM instrument at different locations was used to observe the transient electromagnetic responses of the excavator and to analyze the response amplitudes. The result shows that the tunneling machine affects the advanced detection data and is related to the way the coil is coupled. When the excavator is 6 m from the observatory, the interference of tunneling machine can be ignored.展开更多
To improve the computational efficiency of the reliability-based design optimization(RBDO) of flexible mechanism, particle swarm optimization-advanced extremum response surface method(PSO-AERSM) was proposed by integr...To improve the computational efficiency of the reliability-based design optimization(RBDO) of flexible mechanism, particle swarm optimization-advanced extremum response surface method(PSO-AERSM) was proposed by integrating particle swarm optimization(PSO) algorithm and advanced extremum response surface method(AERSM). Firstly, the AERSM was developed and its mathematical model was established based on artificial neural network, and the PSO algorithm was investigated. And then the RBDO model of flexible mechanism was presented based on AERSM and PSO. Finally, regarding cross-sectional area as design variable, the reliability optimization of flexible mechanism was implemented subject to reliability degree and uncertainties based on the proposed approach. The optimization results show that the cross-section sizes obviously reduce by 22.96 mm^2 while keeping reliability degree. Through the comparison of methods, it is demonstrated that the AERSM holds high computational efficiency while keeping computational precision for the RBDO of flexible mechanism, and PSO algorithm minimizes the response of the objective function. The efforts of this work provide a useful sight for the reliability optimization of flexible mechanism, and enrich and develop the reliability theory as well.展开更多
A novel Pressurized Enriched Oxygen Biological Activated Carbon （PRBAC） method in treating secondary effluent of textile dying-printing ＆ alkali peeling wastewater was configured. The PRBAC reactor simply increased...A novel Pressurized Enriched Oxygen Biological Activated Carbon （PRBAC） method in treating secondary effluent of textile dying-printing ＆ alkali peeling wastewater was configured. The PRBAC reactor simply increased reactor pressure to create an eurtched dissolved oxygen （DO） environment to stimulate the bioactivities of microbes on GAC surface for removing refractory organic matter. Rapid Small- Scaled Colunm Test （RSSCT） was carried out to evaluate the adsorption characteristics of target stream constituents, and over 80% COD components were poorly adsorbable while about 82.5% color inducing matter and 85% UV254 surrogated matter were readily adsorbable. Compared with performances of normal BAC reactor under conventional DO condition, PRBAC achieved 20%, 10% and 50% more removal in COD, color and NH3-N abatement.展开更多
Timing jitter is one of the main factors that influence on the accuracy of time domain precision measurement. Timing jitter compensation is one of the problems people concern. Because of the flaws of median method, PD...Timing jitter is one of the main factors that influence on the accuracy of time domain precision measurement. Timing jitter compensation is one of the problems people concern. Because of the flaws of median method, PDF deconvolution method and synthetic method, we put forward a new method for timing jitter compensation, which is called advanced median method. The theory of the advanced median method based on probability and statistics is analyzed, and the process of the advanced median method is summarized in this paper. Simulation and experiment show that compared with other methods, the new method could compensate timing jitter effectively.展开更多
Dairy wastewater,a kind of high concentration organic wastewater,is produced in large quantities and difficult to treat,and has a negative impact on the ecological environment.In this study,the source,composition,wate...Dairy wastewater,a kind of high concentration organic wastewater,is produced in large quantities and difficult to treat,and has a negative impact on the ecological environment.In this study,the source,composition,water quality characteristics of dairy wastewater and its impact on the ecological environment were analyzed,and the treatment methods of dairy wastewater at home and abroad in recent years were summarized,in order to provide a reference for the treatment of dairy wastewater.展开更多
This paper presents the Taguchi Method, a statistical design modelling for experiments applied in environmental engineering. This method was applied to optimize the treatment conditions of polyester-resin effluent by ...This paper presents the Taguchi Method, a statistical design modelling for experiments applied in environmental engineering. This method was applied to optimize the treatment conditions of polyester-resin effluent by means of Advanced Oxidative Processes (AOPs) using chemical oxygen demand (COD) as response parameter. The influence of each independent parameter including respective interactions was evaluated by Taguchi Method, which allowed determining the most statistically significant variables and conditions to best fit the process. Results showed that Taguchi Method is a very useful tool for environmental engineering field and possible simplifications of analysis and calculations through commercially available software.展开更多
The main objective of this study is to generate accurate synthetic hourly solar radiation data by using an easily accessible open source data.In this regard,a new approach is proposed for estimation of synthetic hourl...The main objective of this study is to generate accurate synthetic hourly solar radiation data by using an easily accessible open source data.In this regard,a new approach is proposed for estimation of synthetic hourly global solar radiation during the day by utilizing only annual solar energy data.First time in literature,a model has been developed for prediction hourly and daily solar radiation based on annual solar energy parameter in this study.Parameters of the model were generated and tested for Turkey and one of them was presented as a case study within this paper.Long term measured hourly horizontal solar irradiance data from a network of Turkish meteorological stations was used to calibrate the model function.The predictions are compared with the solar data available in literature for Turkey.The advanced simple new model is utilized in open source computer program and has the potential to be adapted to other countries.展开更多
An advanced Gauss pseudospectral method(AGPM) was proposed to estimate the parameters of the continuous-time(CT)Hammerstein model.The nonlinear part of the Hammerstein system is approximated with pseudospectral approx...An advanced Gauss pseudospectral method(AGPM) was proposed to estimate the parameters of the continuous-time(CT)Hammerstein model.The nonlinear part of the Hammerstein system is approximated with pseudospectral approximation method.The linear part was written as a controllable canonical form to circumvent the high order time-derivative of the input and output(I/O) signals,which could multiply the measurement noise in the identification procession.Furthermore,an output error minimization was constructed for the CT Hammerstein model identification,which was then transcribed into a nonlinear programming(NLP) problem by AGPM.AGPM could converge to the true values of the CT Hammerstein model with few interpolated Legendre-Gauss(LG) nodes.Lastly,two illustrative examples were proposed to verify the accuracy and efficiency of the method.展开更多
A full automatic tetrahedronal mesh generation method for arbitrary 3D domains is described. First, the classic Delaunay method is coupled with simplified advancing front technique (AFT) to obtain the boundary mesh. T...A full automatic tetrahedronal mesh generation method for arbitrary 3D domains is described. First, the classic Delaunay method is coupled with simplified advancing front technique (AFT) to obtain the boundary mesh. Then, advancing front high quality point placement is used to generate internal points with optimal positions and a Delaunay method is used to insert them efficiently. Finally, optimization procedures are used for mesh quality improvements. Several application examples are presented to demonstrate the robustness and efficiency of the proposed meshing scheme.展开更多
先进的长期演进技术(long term evolution advanced,LTE-advanced)是新一代无线移动通信系统核心技术,如何有效评估这一技术系统性能是当前研究重点之一。在充分理解无线通信系统级仿真基本理论和LTE-advanced系统级仿真若干规范基础上...先进的长期演进技术(long term evolution advanced,LTE-advanced)是新一代无线移动通信系统核心技术,如何有效评估这一技术系统性能是当前研究重点之一。在充分理解无线通信系统级仿真基本理论和LTE-advanced系统级仿真若干规范基础上,梳理LTE-advanced系统级仿真涉及的组织结构,采用模块化设计方法,以此结构为框架搭建系统级仿真平台,实现对LTE-advanced进行系统级仿真。进一步以LTE-advanced系统重要性能参数平均吞吐量为考察指标,重点分析对比了轮询、最大载干比、比例公平这3种调度算法对LTE-advanced网络整体性能的影响。展开更多
AIM: To study the effectiveness of second-linetreatments for advancer gastric cancer by application of Bayesian network meta-analysis.METHODS: Our search covered the literature up to February 2015. The following 6 tre...AIM: To study the effectiveness of second-linetreatments for advancer gastric cancer by application of Bayesian network meta-analysis.METHODS: Our search covered the literature up to February 2015. The following 6 treatments were evaluated:(1) irinotecan(camptothecins);(2) paclitaxel(taxanes class);(3) docetaxel(taxanes);(4) everolimus(mammalian target of rapamycin inhibitors);(5) ramucirumab(vascular endothelial growth factor receptor 2 inhibitors);(6) ramucirumab + paclitaxel. Our methodology was based on standard models of Bayesian network meta-analysis. The reference treatment was best supportive care(BSC). The endpoint was overall survival. Median survival was the outcome measure along with 95% credible intervals. RESULTS: Our search identified a total of 7 randomized controlled trials. These trials included 2298 patients(in 15 treatment arms) in whom a total of 6 active treatments were evaluated as well as BSC. There were 21 head-to-head comparisons(6 direct, 15 indirect). The difference in survival between each of two active treatments(paclitaxel and ramucirumab + paclitaxel) vs BSC was statistically significant, while the other 4 showed no statistical difference. In the 6 head-to-head comparisons between active treatments, no significant survival difference was demonstrated. CONCLUSION: Our results indicate that both paclitaxel monotherapy and ramucirumab + paclitaxel determine a significant prolongation in survival as compared with BSC.展开更多
The mechanism of stress generation and propagation by detonation loading in five separate independent advance of ore breaking patterns is discussed in the paper. An elastic numerical model was developed using AN- SYS/...The mechanism of stress generation and propagation by detonation loading in five separate independent advance of ore breaking patterns is discussed in the paper. An elastic numerical model was developed using AN- SYS/LS-DYNA 3D Nonlinear Dynamic Finite Element Software. In this package ANSYS is the preprocessor and LS-DYNA is the postprocessor. Numerical models in the paper to actual were l：10 and the element mesh was dissected in scanning mode utilizing the symmetry characteristics of the numerical model. Five different advance rates were studied. Parameters, such as the time required to maximum stress, the action time of the available stress, the maximum velocity of the nodes, the stress penetration time, the magnitude of the stress peak and the time duration for high stress were numerically simulated. The 2.2 m advance appeared optimum from an analysis of the simulation results. The results from numerical simulation have been validated by tests with physical models.展开更多
Metal-organic frameworks(MOFs)materials with highly ordered and porous crystalline structure,have excellent performance in advanced oxidation progresses(AOPs)for organic contaminants degradation in water treatment.Thi...Metal-organic frameworks(MOFs)materials with highly ordered and porous crystalline structure,have excellent performance in advanced oxidation progresses(AOPs)for organic contaminants degradation in water treatment.This review intends to summarize the timely references and insights for the recent advances in MOFs that are used in AOPs.Starting with the preparation methodologies,including conventional hydrothermal method,electrochemical method,sol-gel method,and emerging microwave and ultrasound assisted synthesis methods.Application and mechanism for MOFs using in various AOPs of Fenton-like,photocatalysis,catalytic ozonation,persulfate catalysis and other emerging oxidation methods are emphatically discussed.We hope this review can comprehensively summarize the research and application progress of MOFs in AOPs,deepen the understanding of the catalytic mechanisms.展开更多
An efficient Advancing Layer Method(ALM)is presented to create semi-structured prisms on viscous walls,in which a procedure that checks possible front intersections is essential to its efficiency.This paper develops v...An efficient Advancing Layer Method(ALM)is presented to create semi-structured prisms on viscous walls,in which a procedure that checks possible front intersections is essential to its efficiency.This paper develops various novel schemes to improve the algorithm’s efficiency precisely while not sacrificing its robustness and the resulting mesh quality.First,it employs a set of new techniques,and data structures are developed to improve the efficiency of the frontcheck procedure.Then,within each octant,a new filter is developed to reduce the intersection computations in the searching process.In addition,data structures are well designed to store the contiguously accessed data in each computing-intensive loop in a contiguous space for a potentially better cache hit ratio.We built a geometry model library formed by examples of industrial complexity to demonstrate the practicability of the algorithm.All the efforts mentioned above enable us to reduce the percentage of computing time taken by intersection check to an acceptable level(approximately 26%),which make it no longer be the most time-consuming part.展开更多
In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relat...In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.展开更多
A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the ...A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.展开更多
Structural analysis of steel frames is typically performed using beam elements. Since these elements are unable to explicitly capture the local buckling behavior of steel cross-sections, traditional steel design speci...Structural analysis of steel frames is typically performed using beam elements. Since these elements are unable to explicitly capture the local buckling behavior of steel cross-sections, traditional steel design specifications use the concept of cross-section classification to determine the extent to which the strength and deformation capacity of a cross-section are affected by local buckling. The use of plastic design methods are restricted to Class 1 cross-sections, which possess sufficient rotation capacity for plastic hinges to develop and a collapse mechanism to form. Local buckling prevents the development of plastic hinges with such rotation capacity for cross-sections of higher classes and, unless computationally demanding shell elements are used, elastic analysis is required. However, this article demonstrates that local buckling can be mimicked effectively in beam elements by incorporating the continuous strength method (CSM) strain limits into the analysis. Furthermore, by performing an advanced analysis that accounts for both geometric and material nonlinearities, no additional design checks are required. The positive influence of the strain hardening observed in stocky cross-sections can also be harnessed, provided a suitably accurate stress–strain relationship is adopted;a quad-linear material model for hot-rolled steels is described for this purpose. The CSM strain limits allow cross-sections of all slenderness to be analyzed in a consistent advanced analysis framework and to benefit from the appropriate level of load redistribution. The proposed approach is applied herein to individual members, continuous beams, and frames, and is shown to bring significant benefits in terms of accuracy and consistency over current steel design specifications.展开更多
Based on the main research results of estimation methods of surface solar radiation at home and abroad in recent decades, three commonly used estimation models of surface solar radiation have been introduced, and thei...Based on the main research results of estimation methods of surface solar radiation at home and abroad in recent decades, three commonly used estimation models of surface solar radiation have been introduced, and their principles, advantages and disadvantages have been analyzed to provide scientific references for further study of surface solar radiation in future.展开更多
基金Project(41174103)supported by the National Natural Science Foundation of ChinaProject(20110162130008)supported by the PhD Program Foundation of Ministry of Education of ChinaProject(2011BAB04B08)supported by the National Key Technology R&D Program during the 12th Five-Year Plan of China
文摘Within the roadway advanced detection methods, DC resistivity method has an extensive application because of its simple principle and operation. Numerical simulation of the effect of focusing current on advanced detection was carried out using a three-dimensional finite element method （FEM）, meanwhile the electric-field distribution of the point source and nine-point power source were calculated and analyzed with the same electric charges. The results show that the nine-point power source array has a very good ability to focus, and the DC focus method can be used to predict the aquifer abnormality body precisely. By comparing the FEM modelling results with physical simulation results from soil sink, it is shown that the accuracy of forward simulation meets the requirement and the artificial disturbance from roadway has no impact on the DC focus method.
基金co-supported by the National Natural Science Foundation of China (No. 51275138)the Science Foundation of Heilongjiang Provincial Department of Education (No. 12531109)+1 种基金the funding of Hong Kong Scholars Programs (Nos. XJ2015002 and G-YZ90)China’s Postdoctoral Science Funding (No. 2015M580037)
文摘To reasonably implement the reliability analysis and describe the significance of influencing parameters for the multi-failure modes of turbine blisk, advanced multiple response surface method (AMRSM) was proposed for multi-failure mode sensitivity analysis for reliability. The mathematical model of AMRSM was established and the basic principle of multi-failure mode sensitivity analysis for reliability with AMRSM was given. The important parameters of turbine blisk failures are obtained by the multi-failure mode sensitivity analysis of turbine blisk. Through the reliability sensitivity analyses of multiple failure modes (deformation, stress and strain) with the proposed method considering fluid-thermal-solid interaction, it is shown that the comprehensive reliability of turbine blisk is 0.9931 when the allowable deformation, stress and strain are 3.7 x 10(-3) m, 1.0023 x 10(9) Pa and 1.05 x 10(-2) m/m, respectively; the main impact factors of turbine blisk failure are gas velocity, gas temperature and rotational speed. As demonstrated in the comparison of methods (Monte Carlo (MC) method, traditional response surface method (RSM), multiple response surface method (MRSM) and AMRSM), the proposed AMRSM improves computational efficiency with acceptable computational accuracy. The efforts of this study provide the AMRSM with high precision and efficiency for multi-failure mode reliability analysis, and offer a useful insight for the reliability optimization design of multi-failure mode structure. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
基金support received from the National Basic Research Program of China (No2007CB209400)the National Natural Science Foundation of China (No50774085)the Young Scientists Fund of the School Science Foundation of CUMT (No2008A046)
文摘Tunneling machines, or excavators, are large and good conductors and affect the reliability of data gathering and interpretation in advanced detection using transient electromagnetic methods. In our experiment, we used a coincident-loop and central loop type of configuration, where the coil plane l） vertical to and 2） parallel to the working face. A SIROTEM instrument at different locations was used to observe the transient electromagnetic responses of the excavator and to analyze the response amplitudes. The result shows that the tunneling machine affects the advanced detection data and is related to the way the coil is coupled. When the excavator is 6 m from the observatory, the interference of tunneling machine can be ignored.
基金Projects(51275138,51475025)supported by the National Natural Science Foundation of ChinaProject(12531109)supported by the Science Foundation of Heilongjiang Provincial Department of Education,China+1 种基金Projects(XJ2015002,G-YZ90)supported by Hong Kong Scholars Program,ChinaProject(2015M580037)supported by Postdoctoral Science Foundation of China
文摘To improve the computational efficiency of the reliability-based design optimization(RBDO) of flexible mechanism, particle swarm optimization-advanced extremum response surface method(PSO-AERSM) was proposed by integrating particle swarm optimization(PSO) algorithm and advanced extremum response surface method(AERSM). Firstly, the AERSM was developed and its mathematical model was established based on artificial neural network, and the PSO algorithm was investigated. And then the RBDO model of flexible mechanism was presented based on AERSM and PSO. Finally, regarding cross-sectional area as design variable, the reliability optimization of flexible mechanism was implemented subject to reliability degree and uncertainties based on the proposed approach. The optimization results show that the cross-section sizes obviously reduce by 22.96 mm^2 while keeping reliability degree. Through the comparison of methods, it is demonstrated that the AERSM holds high computational efficiency while keeping computational precision for the RBDO of flexible mechanism, and PSO algorithm minimizes the response of the objective function. The efforts of this work provide a useful sight for the reliability optimization of flexible mechanism, and enrich and develop the reliability theory as well.
文摘A novel Pressurized Enriched Oxygen Biological Activated Carbon （PRBAC） method in treating secondary effluent of textile dying-printing ＆ alkali peeling wastewater was configured. The PRBAC reactor simply increased reactor pressure to create an eurtched dissolved oxygen （DO） environment to stimulate the bioactivities of microbes on GAC surface for removing refractory organic matter. Rapid Small- Scaled Colunm Test （RSSCT） was carried out to evaluate the adsorption characteristics of target stream constituents, and over 80% COD components were poorly adsorbable while about 82.5% color inducing matter and 85% UV254 surrogated matter were readily adsorbable. Compared with performances of normal BAC reactor under conventional DO condition, PRBAC achieved 20%, 10% and 50% more removal in COD, color and NH3-N abatement.
基金National Natural Science Foundation of China (50605065)
文摘Timing jitter is one of the main factors that influence on the accuracy of time domain precision measurement. Timing jitter compensation is one of the problems people concern. Because of the flaws of median method, PDF deconvolution method and synthetic method, we put forward a new method for timing jitter compensation, which is called advanced median method. The theory of the advanced median method based on probability and statistics is analyzed, and the process of the advanced median method is summarized in this paper. Simulation and experiment show that compared with other methods, the new method could compensate timing jitter effectively.
文摘Dairy wastewater,a kind of high concentration organic wastewater,is produced in large quantities and difficult to treat,and has a negative impact on the ecological environment.In this study,the source,composition,water quality characteristics of dairy wastewater and its impact on the ecological environment were analyzed,and the treatment methods of dairy wastewater at home and abroad in recent years were summarized,in order to provide a reference for the treatment of dairy wastewater.
文摘This paper presents the Taguchi Method, a statistical design modelling for experiments applied in environmental engineering. This method was applied to optimize the treatment conditions of polyester-resin effluent by means of Advanced Oxidative Processes (AOPs) using chemical oxygen demand (COD) as response parameter. The influence of each independent parameter including respective interactions was evaluated by Taguchi Method, which allowed determining the most statistically significant variables and conditions to best fit the process. Results showed that Taguchi Method is a very useful tool for environmental engineering field and possible simplifications of analysis and calculations through commercially available software.
文摘The main objective of this study is to generate accurate synthetic hourly solar radiation data by using an easily accessible open source data.In this regard,a new approach is proposed for estimation of synthetic hourly global solar radiation during the day by utilizing only annual solar energy data.First time in literature,a model has been developed for prediction hourly and daily solar radiation based on annual solar energy parameter in this study.Parameters of the model were generated and tested for Turkey and one of them was presented as a case study within this paper.Long term measured hourly horizontal solar irradiance data from a network of Turkish meteorological stations was used to calibrate the model function.The predictions are compared with the solar data available in literature for Turkey.The advanced simple new model is utilized in open source computer program and has the potential to be adapted to other countries.
文摘An advanced Gauss pseudospectral method(AGPM) was proposed to estimate the parameters of the continuous-time(CT)Hammerstein model.The nonlinear part of the Hammerstein system is approximated with pseudospectral approximation method.The linear part was written as a controllable canonical form to circumvent the high order time-derivative of the input and output(I/O) signals,which could multiply the measurement noise in the identification procession.Furthermore,an output error minimization was constructed for the CT Hammerstein model identification,which was then transcribed into a nonlinear programming(NLP) problem by AGPM.AGPM could converge to the true values of the CT Hammerstein model with few interpolated Legendre-Gauss(LG) nodes.Lastly,two illustrative examples were proposed to verify the accuracy and efficiency of the method.
文摘A full automatic tetrahedronal mesh generation method for arbitrary 3D domains is described. First, the classic Delaunay method is coupled with simplified advancing front technique (AFT) to obtain the boundary mesh. Then, advancing front high quality point placement is used to generate internal points with optimal positions and a Delaunay method is used to insert them efficiently. Finally, optimization procedures are used for mesh quality improvements. Several application examples are presented to demonstrate the robustness and efficiency of the proposed meshing scheme.
文摘先进的长期演进技术(long term evolution advanced,LTE-advanced)是新一代无线移动通信系统核心技术,如何有效评估这一技术系统性能是当前研究重点之一。在充分理解无线通信系统级仿真基本理论和LTE-advanced系统级仿真若干规范基础上,梳理LTE-advanced系统级仿真涉及的组织结构,采用模块化设计方法,以此结构为框架搭建系统级仿真平台,实现对LTE-advanced进行系统级仿真。进一步以LTE-advanced系统重要性能参数平均吞吐量为考察指标,重点分析对比了轮询、最大载干比、比例公平这3种调度算法对LTE-advanced网络整体性能的影响。
文摘AIM: To study the effectiveness of second-linetreatments for advancer gastric cancer by application of Bayesian network meta-analysis.METHODS: Our search covered the literature up to February 2015. The following 6 treatments were evaluated:(1) irinotecan(camptothecins);(2) paclitaxel(taxanes class);(3) docetaxel(taxanes);(4) everolimus(mammalian target of rapamycin inhibitors);(5) ramucirumab(vascular endothelial growth factor receptor 2 inhibitors);(6) ramucirumab + paclitaxel. Our methodology was based on standard models of Bayesian network meta-analysis. The reference treatment was best supportive care(BSC). The endpoint was overall survival. Median survival was the outcome measure along with 95% credible intervals. RESULTS: Our search identified a total of 7 randomized controlled trials. These trials included 2298 patients(in 15 treatment arms) in whom a total of 6 active treatments were evaluated as well as BSC. There were 21 head-to-head comparisons(6 direct, 15 indirect). The difference in survival between each of two active treatments(paclitaxel and ramucirumab + paclitaxel) vs BSC was statistically significant, while the other 4 showed no statistical difference. In the 6 head-to-head comparisons between active treatments, no significant survival difference was demonstrated. CONCLUSION: Our results indicate that both paclitaxel monotherapy and ramucirumab + paclitaxel determine a significant prolongation in survival as compared with BSC.
文摘The mechanism of stress generation and propagation by detonation loading in five separate independent advance of ore breaking patterns is discussed in the paper. An elastic numerical model was developed using AN- SYS/LS-DYNA 3D Nonlinear Dynamic Finite Element Software. In this package ANSYS is the preprocessor and LS-DYNA is the postprocessor. Numerical models in the paper to actual were l：10 and the element mesh was dissected in scanning mode utilizing the symmetry characteristics of the numerical model. Five different advance rates were studied. Parameters, such as the time required to maximum stress, the action time of the available stress, the maximum velocity of the nodes, the stress penetration time, the magnitude of the stress peak and the time duration for high stress were numerically simulated. The 2.2 m advance appeared optimum from an analysis of the simulation results. The results from numerical simulation have been validated by tests with physical models.
基金supported by the National Natural Science Foundation of China(Nos.21906088,51902169,52170039)the National Science Foundation for Post-doctoral Scientists of China(No.2021T140165)+2 种基金the Heilongjiang Provincial Natural Science Foundation of China(No.LH2020B023)Department of Education Heilongjiang Province(Nos.135309338,135309351)University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(Nos.UNPYSCT-2020068,UNPYSCT-2020067).
文摘Metal-organic frameworks(MOFs)materials with highly ordered and porous crystalline structure,have excellent performance in advanced oxidation progresses(AOPs)for organic contaminants degradation in water treatment.This review intends to summarize the timely references and insights for the recent advances in MOFs that are used in AOPs.Starting with the preparation methodologies,including conventional hydrothermal method,electrochemical method,sol-gel method,and emerging microwave and ultrasound assisted synthesis methods.Application and mechanism for MOFs using in various AOPs of Fenton-like,photocatalysis,catalytic ozonation,persulfate catalysis and other emerging oxidation methods are emphatically discussed.We hope this review can comprehensively summarize the research and application progress of MOFs in AOPs,deepen the understanding of the catalytic mechanisms.
基金co-supported by the Zhejiang Provincial Science and Technology Program,China(No.2021C01108)the Innovative Research Foundation of Ship General Performance,China(No.14022105)the Science and Technology on Scramjet Laboratory Fund,China(No.2022-JCJQ-LB020-05).
文摘An efficient Advancing Layer Method(ALM)is presented to create semi-structured prisms on viscous walls,in which a procedure that checks possible front intersections is essential to its efficiency.This paper develops various novel schemes to improve the algorithm’s efficiency precisely while not sacrificing its robustness and the resulting mesh quality.First,it employs a set of new techniques,and data structures are developed to improve the efficiency of the frontcheck procedure.Then,within each octant,a new filter is developed to reduce the intersection computations in the searching process.In addition,data structures are well designed to store the contiguously accessed data in each computing-intensive loop in a contiguous space for a potentially better cache hit ratio.We built a geometry model library formed by examples of industrial complexity to demonstrate the practicability of the algorithm.All the efforts mentioned above enable us to reduce the percentage of computing time taken by intersection check to an acceptable level(approximately 26%),which make it no longer be the most time-consuming part.
文摘In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.
基金supported by the State Key Laboratory of Coal Resources and Sate Mining,China University of Mining and Technology (No.SKLCRSM13X07)the National Natural Science Foundation of China (No.51174195)+1 种基金Chinese National Programs for Fundamental Research and Development (No.2013CB227900)the Fundamental Research Funds for the Central Universities (No.2014XT01)
文摘A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.
文摘Structural analysis of steel frames is typically performed using beam elements. Since these elements are unable to explicitly capture the local buckling behavior of steel cross-sections, traditional steel design specifications use the concept of cross-section classification to determine the extent to which the strength and deformation capacity of a cross-section are affected by local buckling. The use of plastic design methods are restricted to Class 1 cross-sections, which possess sufficient rotation capacity for plastic hinges to develop and a collapse mechanism to form. Local buckling prevents the development of plastic hinges with such rotation capacity for cross-sections of higher classes and, unless computationally demanding shell elements are used, elastic analysis is required. However, this article demonstrates that local buckling can be mimicked effectively in beam elements by incorporating the continuous strength method (CSM) strain limits into the analysis. Furthermore, by performing an advanced analysis that accounts for both geometric and material nonlinearities, no additional design checks are required. The positive influence of the strain hardening observed in stocky cross-sections can also be harnessed, provided a suitably accurate stress–strain relationship is adopted;a quad-linear material model for hot-rolled steels is described for this purpose. The CSM strain limits allow cross-sections of all slenderness to be analyzed in a consistent advanced analysis framework and to benefit from the appropriate level of load redistribution. The proposed approach is applied herein to individual members, continuous beams, and frames, and is shown to bring significant benefits in terms of accuracy and consistency over current steel design specifications.
基金Sponsored by Applied Basic Research Project for Young Scholars of Shihezi University(2015ZRKXYQ06)Project of International Cooperation and Exchanges of China(2015DFA11660)
文摘Based on the main research results of estimation methods of surface solar radiation at home and abroad in recent decades, three commonly used estimation models of surface solar radiation have been introduced, and their principles, advantages and disadvantages have been analyzed to provide scientific references for further study of surface solar radiation in future.
