Production planning models generated by common modeling systems do not involve constraints for process operations, and a solution optimized by these models is called a quasi-optimal plan. The quasi-optimal plan cannot...Production planning models generated by common modeling systems do not involve constraints for process operations, and a solution optimized by these models is called a quasi-optimal plan. The quasi-optimal plan cannot be executed in practice some time for no corresponding operating conditions. In order to determine a practi- cally feasible optimal plan and corresponding operating conditions of fluidized catalytic cracking unit （FCCU）, a novel close-loop integrated strategy, including determination of a quasi-optimal plan, search of operating conditions of FCCU and revision of the production planning model, was proposed in this article. In the strategy, a generalized genetic algorithm （GA） coupled with a sequential process simulator of FCCU was applied to search operating conditions implementing the quasi-optimal plan of FCCU and output the optimal individual in the GA search as a final genetic individual. When no corresponding operating conditions were found, the final genetic individual based correction （FGIC） method was presented to revise the production planning model, and then a new quasi-optimal production plan was determined. The above steps were repeated until a practically feasible optimal plan and corresponding operating conditions of FCCU were obtained. The close-loop integrated strategy was validated by two cases, and it was indicated that the strategy was efficient in determining a practically executed optimal plan and corresponding operating conditions of FCCU.展开更多
In the process industry, automation and process control systems are widely implemented, information integration is however far away from satisfactory. It remains a hard job for senior managers to make decisions based ...In the process industry, automation and process control systems are widely implemented, information integration is however far away from satisfactory. It remains a hard job for senior managers to make decisions based on the plant-wide real-time integrated information. This paper proposes a multi-layer information integration platform. In the data integration level, the standard for the exchange of product (STEP) and the extensible markup language (XML) are used to unify these data of the chemical process. In the model integration level, the models are integrated by using the neutral model repository and CAPE-OPEN. In the integration of process task, the common object request broker architecture (CORBA) is used as the communication mediator. The XML is taken as the data standard. A uniform information platform is thus constructed and realized. The proposed information integration platform is satisfactorily implemented to solve the Tennessee Eastman (TE) problem.展开更多
Modeling and optimization is crucial to smart chemical process operations.However,a large number of nonlinearities must be considered in a typical chemical process according to complex unit operations,chemical reactio...Modeling and optimization is crucial to smart chemical process operations.However,a large number of nonlinearities must be considered in a typical chemical process according to complex unit operations,chemical reactions and separations.This leads to a great challenge of implementing mechanistic models into industrial-scale problems due to the resulting computational complexity.Thus,this paper presents an efficient hybrid framework of integrating machine learning and particle swarm optimization to overcome the aforementioned difficulties.An industrial propane dehydrogenation process was carried out to demonstrate the validity and efficiency of our method.Firstly,a data set was generated based on process mechanistic simulation validated by industrial data,which provides sufficient and reasonable samples for model training and testing.Secondly,four well-known machine learning methods,namely,K-nearest neighbors,decision tree,support vector machine,and artificial neural network,were compared and used to obtain the prediction models of the processes operation.All of these methods achieved highly accurate model by adjusting model parameters on the basis of high-coverage data and properly features.Finally,optimal process operations were obtained by using the particle swarm optimization approach.展开更多
[Objective] The research aimed to study winter operation process of the surface flow constructed wetland in ＂rianjin area. [Method] In view of climate characteristics in Tianjin, by the way of running under the ice, ...[Objective] The research aimed to study winter operation process of the surface flow constructed wetland in ＂rianjin area. [Method] In view of climate characteristics in Tianjin, by the way of running under the ice, winter operation experiment of the surface flow constructed wetland in Tianjin was conducted, with the expectation to get some useful process parameters to run such systems in North China in winter. [ Result] Although purification effect of the sewage by surface flow constructed wetland in winter was worse than that in other seasons （ average reduction of about 20%）, surface flow constructed wetland running under the ice was feasible in Tianjin area. When surface flow constructed wetland in North China ran under ice in winter, it was suggested that the outlet must be located in a low position to prevent to be completely frozen, and running water depth should not be less than 50 -60 cm. The hydraulic load could be raised on the basis of reflux, and hydraulic retention time should maintain less than 4 d to keep water-soil interface not freezing. Inlet water depth should be increased as much as possible to improve temperature in the system. V Conclusion1 The research could provide reference for promotion and application of the surface flow constructed wetland in North China.展开更多
This paper sets to explore management perceptions regarding the impact of operational process factors on strategy implementation in microfinance organisations in Kenya.Small and medium enterprises(SMEs)play a critical...This paper sets to explore management perceptions regarding the impact of operational process factors on strategy implementation in microfinance organisations in Kenya.Small and medium enterprises(SMEs)play a critical role in developing countries as a source of employment creation and a basis for industrialization.However,the sector receives inadequate financial support from commercial banks as it is considered to bear high risks and operational costs associate with lending small loan amounts.Microfinance organisations(MFOs)that serve this sector will need to expand their operations to increase their outreach to SMEs.Formulation and implementation of competitive strategies will enable MFOs to achieve growth and sustainability.Content,context and operational process factors appear to have a significance positive relationship to the level of strategy implementation.This paper is focusing on operational process factors impacting on strategy implementation and is part of a full study on the topic of strategy implementation in MFOs.Comprehensive literature review provided the theoretical framework for the study.Primary data were collected by means of a survey obtaining 300 self-administered questionnaires from managers in 135 MFOs in Kenya.The study revealed that the level of strategy implementation in MFOs in Kenya is moderate to high.This study has revealed that the operational process category of factors is more significant to the level of strategy implementation than content and context factors.Five operational process factors critical to strategy implementation include:operational planning and monitoring,management control systems,people-strategy fit,teamwork,and effective communication.Further,the level of strategy implementation has significance positive influence to MFOs’financial sustainability and outreach.Practical guidelines are provided to assist MFOs in developing countries to improve the level of strategy implementation by focusing on operational process factors.展开更多
A stochastic model is developed to predict the peniodic operation performance ofthe continuous counter-current adsorption process. The model takes into account theeffects of random backmixing of particles, axial dispe...A stochastic model is developed to predict the peniodic operation performance ofthe continuous counter-current adsorption process. The model takes into account theeffects of random backmixing of particles, axial dispersion of liquid phase, liquid- film mass transfer, intraparticle diffusion and panticle shape, and can revealclearly the behavior of solid and liquid phase in adsorption process. The simulation results agree with the experimental data rather well.展开更多
The types of operation play a key role in facilitating tourism consumption and economic development in a tourism destination. By adopting evolutionary economic geography theory, the paper analyzes the types of operati...The types of operation play a key role in facilitating tourism consumption and economic development in a tourism destination. By adopting evolutionary economic geography theory, the paper analyzes the types of operation in West Lake Scenic Area from 1978 to 2013. First, an evolution process consisting of four stages is underpinned, and they are: the new establishment stage, the preliminary development stage, the speedup development stage, and the stabilized maturity stage. Specifically, the distinct characteristics associated with operation types are compared and evaluated at different stages throughout the process. The evolution trees are introduced to scrutinize types of operation development. The results of evolution trees demonstrate the substantial increase in both numbers and types. Second, by applying GIS spatial analysis, the paper also analyzes the spatial evolution characteristics on the types of operation, and the results unveil the co-existence of centripetal and centrifugal forces: the processes of spatial agglomeration and spatial dispersion. More specifically, we recognize the spatial process includes the emergence of node and concentration(1978–1995), the sparse distribution and intensity reduction(1996–2002), the patchy distribution and spatial agglomeration intensification(2003–2008), the dispersed distribution and core area agglomeration(2009–2013). Lastly, path dependence on resource endowment, government and market innovation, knowledge learning and spillover can reasonably explain the types of operation evolution. In conclusion, the evolutionary economic geography theories provide new theoretical and empirical perspectives for tourism policy analysis. At the same time, our comprehensive evidences impart more comprehensive insights and offer useful managerial and policy implications.展开更多
This paper considers a special class of operator self-similar processes Markov processes {X（t）, t≥0} with independent self-similar components, that is, X （ t ） =（X^1（t）,…,X^d（t））, where {X^i（t）,t≥0}, i=...This paper considers a special class of operator self-similar processes Markov processes {X（t）, t≥0} with independent self-similar components, that is, X （ t ） =（X^1（t）,…,X^d（t））, where {X^i（t）,t≥0}, i=1,2,…,d are d independent real valued self-similar Markov processes. By means of Brel-Cantelli lemma, we give two results about asymptotic property as t→∞ of sample paths for two special classes of Markov processes with independent self-similar components.展开更多
A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic response...A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic responses. In order to reduce structural vibration, it is important to obtain the modal parameters information of a ship. However, the traditional modal parameter identification methods are not suitable since the excitation information is difficult to obtain. Natural excitation technique-eigensystem realization algorithm （NExT-ERA） is an operational modal identification method which abstracts modal parameters only from the response signals, and it is based on the assumption that the input to the structure is pure white noise. Hence, it is necessary to study the influence of harmonic excitations while applying the NExT-ERA method to a ship structure. The results of this research paper indicate the practical experiences under ambient excitation, ship model experiments were successfully done in the modal parameters identification only when the harmonic frequencies were not too close to the modal frequencies.展开更多
Symbolic circuit simulator is traditionally applied to the small-signal analysis of analog circuits. This paper establishes a symbolic behavioral macromodeling method applicable to both small-signal and large-signal a...Symbolic circuit simulator is traditionally applied to the small-signal analysis of analog circuits. This paper establishes a symbolic behavioral macromodeling method applicable to both small-signal and large-signal analysis of general two-stage operational amplifiers （op-amps）. The proposed method creates a two-pole parametric macromodel whose parameters are analytical functions of the circuit element parameters generated by a symbolic circuit simulator. A moment matching technique is used in deriving the analytical model parameter. The created parametric behavioral model can be used for op-amps performance simulation in both frequency and time domains. In particular, the parametric models are highly suited for fast statistical simulation of op-amps in the time-domain. Experiment results show that the statistical distributions of the op-amp slew and settling time characterized by the proposed model agree well with the transistor-level results in addition to achieving significant speedup.展开更多
An alternative proof of factorization theorem for Drell–Yan process that works at operator level is presented in this paper. Contributions of interactions after the hard collision for such inclusive processes are pro...An alternative proof of factorization theorem for Drell–Yan process that works at operator level is presented in this paper. Contributions of interactions after the hard collision for such inclusive processes are proved to be canceled at operator level according to the unitarity of time evolution operator. After this cancellation, there are no longer leading pinch singular surface in Glauber region in the time evolution of electromagnetic currents. Effects of soft gluons are absorbed into Wilson lines of scalar-polarized gluons. Cancelation of soft gluons is attribute to unitarity of time evolution operator and such Wilson lines.展开更多
In this paper the concepts of the boundary value problem of abstract kinetic equation with the first kind of critical parameter γ 0 and generalized periodic boundary conditions are introduced in a Lebesgue space whic...In this paper the concepts of the boundary value problem of abstract kinetic equation with the first kind of critical parameter γ 0 and generalized periodic boundary conditions are introduced in a Lebesgue space which consists of functions with vector valued in a general Banach space, and then describe the solution of these abstract boundary value problem by the abstract linear integral operator of Volterra type. We call this process the integral operator solving process.展开更多
In this work,the dynamics and operation of the totally reboiled reactive distillation columns are visualized in terms of transfer function based process models.This kind of processes is found to be characterized by un...In this work,the dynamics and operation of the totally reboiled reactive distillation columns are visualized in terms of transfer function based process models.This kind of processes is found to be characterized by underdamped step responses due to the special topological configuration and the intricate interplay between the reaction operation and the separation operation involved.The under-dampness can be substantially alleviated through the tight inventory control of bottom reboiler and this presents beneficial effects to process dynamics and operation.Two totally reboiled reactive distillation columns,separating,respectively,a hypothetical synthesis reaction from reactants A and B to product C,and a real decomposition reaction from 1,4-butanediol to tetrahydrofuran and water,are employed to demonstrate these uncommon behaviors.The results obtained give full support to the above qualitative interpretation.Despite the strong influences of reaction kinetics and thermodynamic properties of the reacting mixtures,the totally reboiled reactive distillation columns are generally considered to present such unique behaviors and require tight inventory control of bottom reboiler to facilitate their control system development.展开更多
In the process of hospital management, human resources management occupies an important position. Paying attention to human resources management is of great significance to the promotion of hospital medical service le...In the process of hospital management, human resources management occupies an important position. Paying attention to human resources management is of great significance to the promotion of hospital medical service level and management quality, and plays a key role in enhancing the comprehensive strength of the hospital. The continuous innovation and reform of hospital management system can improve the level of hospital human resources management, thus avoiding unfair salary distribution and other issues. It can also mobilize staff's work enthusiasm and initiative, correct working attitude and provide high-quality medical services for patients. The implementation of people-oriented management strategies in human resources management of hospitals can fully tap the potential of talents and ensure the overall operation level of hospitals and the quality of hospital management. Based on the analysis of the implementation of people-oriented management in human resources management, this paper formulates reasonable application countermeasures.展开更多
In this work, a liquid-gas heterogeneous microreactor was developed for investigating continuous crystallization of dolutegravir sodium(DTG), as well as revealing reaction kinetics and mixing mechanism with 3-min data...In this work, a liquid-gas heterogeneous microreactor was developed for investigating continuous crystallization of dolutegravir sodium(DTG), as well as revealing reaction kinetics and mixing mechanism with 3-min data acquisition. The reaction kinetics models were established by visually recording the concentration variation of reactants over time in the microchannel via adding pH-sensitive fluorescent dye. The mixing intensification mechanism of liquid-gas flow was quantified through the fluorescent signal to indicate mixing process, demonstrating an outstanding mixing performance with a mixing time less than 0.1 s. Compared with batch crystallization, continuous synthesis of dolutegravir sodium using liquid-gas heterogenous microreactor optimizes crystal distribution size, and successfully modifies the crystal morphology in needle-like habit instead of rod-like habit. The microreactor continuous crystallization can run for 5 h without crystal blockage and achieve D90 of DTG less than 30 μm. This work provides a feasible approach for continuously synthesizing dolutegravir sodium, and can optimize the existing pharmaceutical crystallization.展开更多
The mass and thermal coupling makes the control of the reactive double dividing-wall distillation column(R-DDWDC) an especially challenging issue with a highly interactive nature. With reference to the separation of a...The mass and thermal coupling makes the control of the reactive double dividing-wall distillation column(R-DDWDC) an especially challenging issue with a highly interactive nature. With reference to the separation of an ideal endothermic quaternary reversible reaction with the most unfavorable ranking of relative volatilities(A + B ■ C + D with α_(A)>α_(C)>α_(D)>α_(B)), the operation rationality of the R-DDWDC is studied in this contribution. The four-point single temperature control system leads to great steady-state discrepancies in the compositions of products C and D and the reason stems essentially from the failure in keeping strictly the stoichiometric ratio between reactants A and B. A temperature plus temperature cascade control scheme is then employed to reinforce the stoichiometric ratio control and helps to secure a substantial abatement in the steady-state discrepancies. A temperature difference plus temperature cascade control scheme is finally synthesized and leads even to better performance than the most effective double temperature difference control scheme. These outcomes reveal not only the operation feasibility of the R-DDWDC but also the general significance of the proposed temperature difference plus temperature cascade control scheme to the inferential control of any other complicated distillation columns.展开更多
This paper studies the vapor pressure of water and precipitation situation in Lu'an Ground Station in Dabie Mountain area from 1979 to 1998.And the atmospheric perceivable water in Dabie Mountain can be calculated...This paper studies the vapor pressure of water and precipitation situation in Lu'an Ground Station in Dabie Mountain area from 1979 to 1998.And the atmospheric perceivable water in Dabie Mountain can be calculated by virtue of the empirical formula for atmospheric perceivable water.Besides,by analyzing the data,the seasonal changes of perceivable water in Dabie Mountain and the efficiency of precipitation of each weather system is acquired.The results show that there is a great potential for precipitation enhancement in Dabie Mountain.This paper introduces the processes and operation forms of precipitation enhancement for impounding water in reservoirs in Dabie Mountain region.展开更多
Due to the topological structure of double columns and multiple separating sections in dividing-wall distillation columns(DWDCs),the development of vapor recompressed dividing-wall distillation columns(DWDC-VRHPs)repr...Due to the topological structure of double columns and multiple separating sections in dividing-wall distillation columns(DWDCs),the development of vapor recompressed dividing-wall distillation columns(DWDC-VRHPs)represents a challenging issue with great complexities and tediousness.For the separations of light-component dominated and wide boiling-point ternary mixtures,because the purification of the light-component from the intermediate-and heavy-components incurs the primary energy dissipation,the application of vapor recompressed heat pumps(VRHP)should be aimed to reduce the irreversibility and this leads to the generation of the optimum topological structures of the DWDC-VRHPs,i.e.,a DWDC plus a two-stage VRHP.The first-stage VRHP is to preheat feed,not only taking the advantages of the small temperature elevation available but also favoring the mass transfer between the vapor and liquid phases through feed splitting.The second-stage VRHP is to reduce further separation irreversibility.The philosophy can be applied to any DWDCs no matter where the dividing wall locates.Two case studies on the separations of ternary mixtures of benzene,toluene,and o-xylene and n-pentane,n-hexane,and n-heptane demonstrate the economic optimality of the proposed DWDC-VRHPs and reveal the inherent interplay between internal and external process integration.展开更多
文摘Production planning models generated by common modeling systems do not involve constraints for process operations, and a solution optimized by these models is called a quasi-optimal plan. The quasi-optimal plan cannot be executed in practice some time for no corresponding operating conditions. In order to determine a practi- cally feasible optimal plan and corresponding operating conditions of fluidized catalytic cracking unit （FCCU）, a novel close-loop integrated strategy, including determination of a quasi-optimal plan, search of operating conditions of FCCU and revision of the production planning model, was proposed in this article. In the strategy, a generalized genetic algorithm （GA） coupled with a sequential process simulator of FCCU was applied to search operating conditions implementing the quasi-optimal plan of FCCU and output the optimal individual in the GA search as a final genetic individual. When no corresponding operating conditions were found, the final genetic individual based correction （FGIC） method was presented to revise the production planning model, and then a new quasi-optimal production plan was determined. The above steps were repeated until a practically feasible optimal plan and corresponding operating conditions of FCCU were obtained. The close-loop integrated strategy was validated by two cases, and it was indicated that the strategy was efficient in determining a practically executed optimal plan and corresponding operating conditions of FCCU.
文摘In the process industry, automation and process control systems are widely implemented, information integration is however far away from satisfactory. It remains a hard job for senior managers to make decisions based on the plant-wide real-time integrated information. This paper proposes a multi-layer information integration platform. In the data integration level, the standard for the exchange of product (STEP) and the extensible markup language (XML) are used to unify these data of the chemical process. In the model integration level, the models are integrated by using the neutral model repository and CAPE-OPEN. In the integration of process task, the common object request broker architecture (CORBA) is used as the communication mediator. The XML is taken as the data standard. A uniform information platform is thus constructed and realized. The proposed information integration platform is satisfactorily implemented to solve the Tennessee Eastman (TE) problem.
基金This work was supported by the“Zhujiang Talent Program”High Talent Project of Guangdong Province(Grant No.2017GC010614)the National Natural Science Foundation of China(Grant No.22078372).
文摘Modeling and optimization is crucial to smart chemical process operations.However,a large number of nonlinearities must be considered in a typical chemical process according to complex unit operations,chemical reactions and separations.This leads to a great challenge of implementing mechanistic models into industrial-scale problems due to the resulting computational complexity.Thus,this paper presents an efficient hybrid framework of integrating machine learning and particle swarm optimization to overcome the aforementioned difficulties.An industrial propane dehydrogenation process was carried out to demonstrate the validity and efficiency of our method.Firstly,a data set was generated based on process mechanistic simulation validated by industrial data,which provides sufficient and reasonable samples for model training and testing.Secondly,four well-known machine learning methods,namely,K-nearest neighbors,decision tree,support vector machine,and artificial neural network,were compared and used to obtain the prediction models of the processes operation.All of these methods achieved highly accurate model by adjusting model parameters on the basis of high-coverage data and properly features.Finally,optimal process operations were obtained by using the particle swarm optimization approach.
基金Supported by Special Project of the Science Research in Public Service Industry,Ministry of Water Resources,China(2011-BH140002)
文摘[Objective] The research aimed to study winter operation process of the surface flow constructed wetland in ＂rianjin area. [Method] In view of climate characteristics in Tianjin, by the way of running under the ice, winter operation experiment of the surface flow constructed wetland in Tianjin was conducted, with the expectation to get some useful process parameters to run such systems in North China in winter. [ Result] Although purification effect of the sewage by surface flow constructed wetland in winter was worse than that in other seasons （ average reduction of about 20%）, surface flow constructed wetland running under the ice was feasible in Tianjin area. When surface flow constructed wetland in North China ran under ice in winter, it was suggested that the outlet must be located in a low position to prevent to be completely frozen, and running water depth should not be less than 50 -60 cm. The hydraulic load could be raised on the basis of reflux, and hydraulic retention time should maintain less than 4 d to keep water-soil interface not freezing. Inlet water depth should be increased as much as possible to improve temperature in the system. V Conclusion1 The research could provide reference for promotion and application of the surface flow constructed wetland in North China.
文摘This paper sets to explore management perceptions regarding the impact of operational process factors on strategy implementation in microfinance organisations in Kenya.Small and medium enterprises(SMEs)play a critical role in developing countries as a source of employment creation and a basis for industrialization.However,the sector receives inadequate financial support from commercial banks as it is considered to bear high risks and operational costs associate with lending small loan amounts.Microfinance organisations(MFOs)that serve this sector will need to expand their operations to increase their outreach to SMEs.Formulation and implementation of competitive strategies will enable MFOs to achieve growth and sustainability.Content,context and operational process factors appear to have a significance positive relationship to the level of strategy implementation.This paper is focusing on operational process factors impacting on strategy implementation and is part of a full study on the topic of strategy implementation in MFOs.Comprehensive literature review provided the theoretical framework for the study.Primary data were collected by means of a survey obtaining 300 self-administered questionnaires from managers in 135 MFOs in Kenya.The study revealed that the level of strategy implementation in MFOs in Kenya is moderate to high.This study has revealed that the operational process category of factors is more significant to the level of strategy implementation than content and context factors.Five operational process factors critical to strategy implementation include:operational planning and monitoring,management control systems,people-strategy fit,teamwork,and effective communication.Further,the level of strategy implementation has significance positive influence to MFOs’financial sustainability and outreach.Practical guidelines are provided to assist MFOs in developing countries to improve the level of strategy implementation by focusing on operational process factors.
文摘A stochastic model is developed to predict the peniodic operation performance ofthe continuous counter-current adsorption process. The model takes into account theeffects of random backmixing of particles, axial dispersion of liquid phase, liquid- film mass transfer, intraparticle diffusion and panticle shape, and can revealclearly the behavior of solid and liquid phase in adsorption process. The simulation results agree with the experimental data rather well.
基金Under the auspices of National Natural Science Foundation of China(No.41230631,41471130)
文摘The types of operation play a key role in facilitating tourism consumption and economic development in a tourism destination. By adopting evolutionary economic geography theory, the paper analyzes the types of operation in West Lake Scenic Area from 1978 to 2013. First, an evolution process consisting of four stages is underpinned, and they are: the new establishment stage, the preliminary development stage, the speedup development stage, and the stabilized maturity stage. Specifically, the distinct characteristics associated with operation types are compared and evaluated at different stages throughout the process. The evolution trees are introduced to scrutinize types of operation development. The results of evolution trees demonstrate the substantial increase in both numbers and types. Second, by applying GIS spatial analysis, the paper also analyzes the spatial evolution characteristics on the types of operation, and the results unveil the co-existence of centripetal and centrifugal forces: the processes of spatial agglomeration and spatial dispersion. More specifically, we recognize the spatial process includes the emergence of node and concentration(1978–1995), the sparse distribution and intensity reduction(1996–2002), the patchy distribution and spatial agglomeration intensification(2003–2008), the dispersed distribution and core area agglomeration(2009–2013). Lastly, path dependence on resource endowment, government and market innovation, knowledge learning and spillover can reasonably explain the types of operation evolution. In conclusion, the evolutionary economic geography theories provide new theoretical and empirical perspectives for tourism policy analysis. At the same time, our comprehensive evidences impart more comprehensive insights and offer useful managerial and policy implications.
文摘This paper considers a special class of operator self-similar processes Markov processes {X（t）, t≥0} with independent self-similar components, that is, X （ t ） =（X^1（t）,…,X^d（t））, where {X^i（t）,t≥0}, i=1,2,…,d are d independent real valued self-similar Markov processes. By means of Brel-Cantelli lemma, we give two results about asymptotic property as t→∞ of sample paths for two special classes of Markov processes with independent self-similar components.
基金Supported by the National Natural Science Foundation of China（51079027）
文摘A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic responses. In order to reduce structural vibration, it is important to obtain the modal parameters information of a ship. However, the traditional modal parameter identification methods are not suitable since the excitation information is difficult to obtain. Natural excitation technique-eigensystem realization algorithm （NExT-ERA） is an operational modal identification method which abstracts modal parameters only from the response signals, and it is based on the assumption that the input to the structure is pure white noise. Hence, it is necessary to study the influence of harmonic excitations while applying the NExT-ERA method to a ship structure. The results of this research paper indicate the practical experiences under ambient excitation, ship model experiments were successfully done in the modal parameters identification only when the harmonic frequencies were not too close to the modal frequencies.
文摘Symbolic circuit simulator is traditionally applied to the small-signal analysis of analog circuits. This paper establishes a symbolic behavioral macromodeling method applicable to both small-signal and large-signal analysis of general two-stage operational amplifiers （op-amps）. The proposed method creates a two-pole parametric macromodel whose parameters are analytical functions of the circuit element parameters generated by a symbolic circuit simulator. A moment matching technique is used in deriving the analytical model parameter. The created parametric behavioral model can be used for op-amps performance simulation in both frequency and time domains. In particular, the parametric models are highly suited for fast statistical simulation of op-amps in the time-domain. Experiment results show that the statistical distributions of the op-amp slew and settling time characterized by the proposed model agree well with the transistor-level results in addition to achieving significant speedup.
基金Supported by the National Natural Science Foundation of China under Grant No.11275242
文摘An alternative proof of factorization theorem for Drell–Yan process that works at operator level is presented in this paper. Contributions of interactions after the hard collision for such inclusive processes are proved to be canceled at operator level according to the unitarity of time evolution operator. After this cancellation, there are no longer leading pinch singular surface in Glauber region in the time evolution of electromagnetic currents. Effects of soft gluons are absorbed into Wilson lines of scalar-polarized gluons. Cancelation of soft gluons is attribute to unitarity of time evolution operator and such Wilson lines.
文摘In this paper the concepts of the boundary value problem of abstract kinetic equation with the first kind of critical parameter γ 0 and generalized periodic boundary conditions are introduced in a Lebesgue space which consists of functions with vector valued in a general Banach space, and then describe the solution of these abstract boundary value problem by the abstract linear integral operator of Volterra type. We call this process the integral operator solving process.
基金Supported by The National Natural Science Foundation of China(21076015,21376018,and 21576014)The Fundamental Research Funds for the Central Universities(ZY1503)
文摘In this work,the dynamics and operation of the totally reboiled reactive distillation columns are visualized in terms of transfer function based process models.This kind of processes is found to be characterized by underdamped step responses due to the special topological configuration and the intricate interplay between the reaction operation and the separation operation involved.The under-dampness can be substantially alleviated through the tight inventory control of bottom reboiler and this presents beneficial effects to process dynamics and operation.Two totally reboiled reactive distillation columns,separating,respectively,a hypothetical synthesis reaction from reactants A and B to product C,and a real decomposition reaction from 1,4-butanediol to tetrahydrofuran and water,are employed to demonstrate these uncommon behaviors.The results obtained give full support to the above qualitative interpretation.Despite the strong influences of reaction kinetics and thermodynamic properties of the reacting mixtures,the totally reboiled reactive distillation columns are generally considered to present such unique behaviors and require tight inventory control of bottom reboiler to facilitate their control system development.
文摘In the process of hospital management, human resources management occupies an important position. Paying attention to human resources management is of great significance to the promotion of hospital medical service level and management quality, and plays a key role in enhancing the comprehensive strength of the hospital. The continuous innovation and reform of hospital management system can improve the level of hospital human resources management, thus avoiding unfair salary distribution and other issues. It can also mobilize staff's work enthusiasm and initiative, correct working attitude and provide high-quality medical services for patients. The implementation of people-oriented management strategies in human resources management of hospitals can fully tap the potential of talents and ensure the overall operation level of hospitals and the quality of hospital management. Based on the analysis of the implementation of people-oriented management in human resources management, this paper formulates reasonable application countermeasures.
基金supported by the Natural Science Foundation of the Science and Technology Commission of Shanghai Municipality(No.19ZR1472200)National Natural Science Foundation of China(No.22178072)。
文摘In this work, a liquid-gas heterogeneous microreactor was developed for investigating continuous crystallization of dolutegravir sodium(DTG), as well as revealing reaction kinetics and mixing mechanism with 3-min data acquisition. The reaction kinetics models were established by visually recording the concentration variation of reactants over time in the microchannel via adding pH-sensitive fluorescent dye. The mixing intensification mechanism of liquid-gas flow was quantified through the fluorescent signal to indicate mixing process, demonstrating an outstanding mixing performance with a mixing time less than 0.1 s. Compared with batch crystallization, continuous synthesis of dolutegravir sodium using liquid-gas heterogenous microreactor optimizes crystal distribution size, and successfully modifies the crystal morphology in needle-like habit instead of rod-like habit. The microreactor continuous crystallization can run for 5 h without crystal blockage and achieve D90 of DTG less than 30 μm. This work provides a feasible approach for continuously synthesizing dolutegravir sodium, and can optimize the existing pharmaceutical crystallization.
基金the financial support from National Natural Science Foundation of China (21878011)。
文摘The mass and thermal coupling makes the control of the reactive double dividing-wall distillation column(R-DDWDC) an especially challenging issue with a highly interactive nature. With reference to the separation of an ideal endothermic quaternary reversible reaction with the most unfavorable ranking of relative volatilities(A + B ■ C + D with α_(A)>α_(C)>α_(D)>α_(B)), the operation rationality of the R-DDWDC is studied in this contribution. The four-point single temperature control system leads to great steady-state discrepancies in the compositions of products C and D and the reason stems essentially from the failure in keeping strictly the stoichiometric ratio between reactants A and B. A temperature plus temperature cascade control scheme is then employed to reinforce the stoichiometric ratio control and helps to secure a substantial abatement in the steady-state discrepancies. A temperature difference plus temperature cascade control scheme is finally synthesized and leads even to better performance than the most effective double temperature difference control scheme. These outcomes reveal not only the operation feasibility of the R-DDWDC but also the general significance of the proposed temperature difference plus temperature cascade control scheme to the inferential control of any other complicated distillation columns.
基金Supported by China Meteorological Administration (Provincial Figure Operation System Based on the New Generation Radar)The Program of Experimental Investigation on the Development and Utilization of Aerial Cloud Resource in Anhui Province
文摘This paper studies the vapor pressure of water and precipitation situation in Lu'an Ground Station in Dabie Mountain area from 1979 to 1998.And the atmospheric perceivable water in Dabie Mountain can be calculated by virtue of the empirical formula for atmospheric perceivable water.Besides,by analyzing the data,the seasonal changes of perceivable water in Dabie Mountain and the efficiency of precipitation of each weather system is acquired.The results show that there is a great potential for precipitation enhancement in Dabie Mountain.This paper introduces the processes and operation forms of precipitation enhancement for impounding water in reservoirs in Dabie Mountain region.
基金financial financial support from National Natural Science Foundation of China(218780112167601121808007)。
文摘Due to the topological structure of double columns and multiple separating sections in dividing-wall distillation columns(DWDCs),the development of vapor recompressed dividing-wall distillation columns(DWDC-VRHPs)represents a challenging issue with great complexities and tediousness.For the separations of light-component dominated and wide boiling-point ternary mixtures,because the purification of the light-component from the intermediate-and heavy-components incurs the primary energy dissipation,the application of vapor recompressed heat pumps(VRHP)should be aimed to reduce the irreversibility and this leads to the generation of the optimum topological structures of the DWDC-VRHPs,i.e.,a DWDC plus a two-stage VRHP.The first-stage VRHP is to preheat feed,not only taking the advantages of the small temperature elevation available but also favoring the mass transfer between the vapor and liquid phases through feed splitting.The second-stage VRHP is to reduce further separation irreversibility.The philosophy can be applied to any DWDCs no matter where the dividing wall locates.Two case studies on the separations of ternary mixtures of benzene,toluene,and o-xylene and n-pentane,n-hexane,and n-heptane demonstrate the economic optimality of the proposed DWDC-VRHPs and reveal the inherent interplay between internal and external process integration.
