Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity ...Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.展开更多
From the perspective of a community energy operator,a two-stage optimal scheduling model of a community integrated energy system is proposed by integrating information on controllable loads.The day-ahead scheduling an...From the perspective of a community energy operator,a two-stage optimal scheduling model of a community integrated energy system is proposed by integrating information on controllable loads.The day-ahead scheduling analyzes whether various controllable loads participate in the optimization and investigates the impact of their responses on the operating economy of the community integrated energy system(IES)before and after;the intra-day scheduling proposes a two-stage rolling optimization model based on the day-ahead scheduling scheme,taking into account the fluctuation of wind turbine output and load within a short period of time and according to the different response rates of heat and cooling power,and solves the adjusted output of each controllable device.The simulation results show that the optimal scheduling of controllable loads effectively reduces the comprehensive operating costs of community IES;the two-stage optimal scheduling model can meet the energy demand of customers while effectively and timely suppressing the random fluctuations on both sides of the source and load during the intra-day stage,realizing the economic and smooth operation of IES.展开更多
As energy efficiency and indoor comfort increasingly become key standards in modern residential and office environments,research on intelligent fan speed control systems has become particularly important.This study ai...As energy efficiency and indoor comfort increasingly become key standards in modern residential and office environments,research on intelligent fan speed control systems has become particularly important.This study aims to develop a temperature-feedback-based fan speed optimization strategy to achieve higher energy efficiency and user comfort.Firstly,by analyzing existing fan speed control technologies,their main limitations are identified,such as the inability to achieve smooth speed transitions.To address this issue,a BP-PID speed control algorithm is designed,which dynamically adjusts fan speed based on indoor temperature changes.Experimental validation demonstrates that the designed system can achieve smooth speed transitions compared to traditional fan systems while maintaining stable indoor temperatures.Furthermore,the real-time responsiveness of the system is crucial for enhancing user comfort.Our research not only demonstrates the feasibility of temperature-based fan speed optimization strategies in both theory and practice but also provides valuable insights for energy management in future smart home environments.Ultimately,this research outcome will facilitate the development of smart home systems and have a positive impact on environmental sustainability.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
Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With th...Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves:convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.展开更多
After steam discharge in heavy oil reservoirs,the distribution of temperature,pressure,and permeability in different wells becomes irregular.Flow channels can easily be produced,which affect the sweep efficiency of th...After steam discharge in heavy oil reservoirs,the distribution of temperature,pressure,and permeability in different wells becomes irregular.Flow channels can easily be produced,which affect the sweep efficiency of the oil displacement.Previous studies have shown that the salting-out plugging method can effectively block these channels in high-temperature reservoirs,improve the suction profile,and increase oil production.In the present study,the optimal dosage of the plugging agent is determined taking into account connection transmissibility and inter-well volumes.Together with the connectivity model,a water flooding simulation model is introduced.Moreover,a non-gradient stochastic disturbance algorithm is used to obtain the optimal plugging agent dosage,which provides the basis for the high-temperature salting-out plugging agent adjustment in the field.展开更多
A two-stage upflow anaerobic sludge blanket (UASB) and sequencing batch reactor (SBR) system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to impro...A two-stage upflow anaerobic sludge blanket (UASB) and sequencing batch reactor (SBR) system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to improve the total nitrogen (TN) removal efficiency and to reduce the COD requirement for denitrification, the raw leachate with recycled SBR nitrification supematant was pumped into the first-stage UASB (UASB1) to achieve simultaneous denitrification and methanogenesis. The results showed that UASB1 played an important role in COD removal and UASB2 and SBR further enhanced the nutrient removal efficiency. When the organic loading rates of UASB1, UASB2 and SBR were 11.95, 1.63 and 1.29 kg COD/(m^3.day), respectively, the total COD removal efficiency of the whole system reached 96.7%. The SBR acted as the real undertaker for NH4^+-N removal due to aerobic nitrification. The system obtained about 99.7% of NH4^+-N removal efficiency at relatively low temperature (14.9-10.9℃). More than 98.3% TN was removed through complete denitrification in UASB 1 and SBR. In addition, temperature had a significant effect on the rates of nitrification and denitrification rather than the removal of TN and NH4^+-N once the complete nitrification and denitrification were achieved.展开更多
To predict and optimize the temperature distribution of slab continuous casting in steady operational state, a three-dimensional model (named "offline model") based on the heat transfer and solidification theories...To predict and optimize the temperature distribution of slab continuous casting in steady operational state, a three-dimensional model (named "offline model") based on the heat transfer and solidification theories was developed. Both heat transfer and flux distribution characteristics of the nozzle sprays on the slab were considered, and the complicated boundary conditions, such as spray cooling, natural convection, thermal radiation as well as contact cooling of individual rolls were involved in the model. By using the calibrated caster dependent model factors, the calculated temperature and shell thickness accorded well with the measured. Furthermore, a dynamic secondary water cooling control system was also developed on the basis of a two-dimensional transient heat transfer model (named "online model") and incremental PID control algorithm to reduce slab surface temperature fluctuation in unsteady state. Compared with the traditional spray table control method, the present online model and dynamic PID control demonstrate a higher capability and flexibility to adjust cooling water flowrate and reduce slab surface temperature fluctuation when the casting speed is changed.展开更多
A design method of an intelligent temperature control system based on single-chip microcomputer is presented in this paper. The intelligent temperature control system is divided into four parts: monitor,heater,control...A design method of an intelligent temperature control system based on single-chip microcomputer is presented in this paper. The intelligent temperature control system is divided into four parts: monitor,heater,controlled process and feedback loop. Among them,the temperature detection circuit is designed with the conductivity of water by sensor detection. The optical coupler MOC3041 is used to implement the power control circuit,whose control object is 1 kW electric heater with the 220 V alternating current power; keyboard and display circuit SMC1602A include four buttons and LCD display to achieve human-computer interaction; Based on single-chip system STC89C52,the sensor signal and keyboard set target temperature are compared to the power automatically in order to finish the water temperature control. Through the static and dynamic data testing,the results show that the proposed method provides an effective way to realize the real-time acquisition and control of temperature.展开更多
A temperature control system of 31m vertical forced air-circulation quench furnace is proposed, which is a kind of equipment critical for thermal treatment of aluminum alloy components that are widely used in aerospac...A temperature control system of 31m vertical forced air-circulation quench furnace is proposed, which is a kind of equipment critical for thermal treatment of aluminum alloy components that are widely used in aerospace industry. For the effective operation of the furnace, it is essential to analyze the radial temperature distribution of the furnace. A set of thermodynamic balance equations modeling is established firsdy. By utilizing the numerical analysis result to modify the temperature measurements, the control accuracy and precision of the temperature are truly guaranteed. Furthermore, the multivariable decoupling self-learning PID control algorithm based on the characteristics of strong coupling between the multi-zones in the large-scaled furnace is implemented to ensure the true homogeneity of the axial temperature distribution. Finally, the redundant structure composed of industrial control computers and touch panels leads to great improvement of system reliability.展开更多
Temperature inferential control (TIC) is studied for a reactive distillation column with double reactive sections (RDC-DRSs) processing a hypothetical two-stage consecutive reversible reaction (A + B■C + D, C + B■E ...Temperature inferential control (TIC) is studied for a reactive distillation column with double reactive sections (RDC-DRSs) processing a hypothetical two-stage consecutive reversible reaction (A + B■C + D, C + B■E + D with αD > αB > αC > αA > αE). Because of the complicated dynamic behaviors, the controlled stages by sensitivity analysis lead to great steady-state deviations (SSDs) in top and bottom product purities. Since TIC involves considerably reduced settling times in comparison with direct composition control, small SSDs in product qualities correspond generally to small transient deviations (TDs) in product qualities. An objective function that measures SSDs in product qualities is formulated to represent the performance of a TIC system and an iterative procedure is devised to search for the best control configuration. The application of the procedure to the RDC-DRS gives considerably suppressed TDs and SSDs in top and bottom product qualities as compared with the one by sensitivity analysis. The method is simpler in principle and less computationally intensive than the current practice. These striking outcomes show the effectiveness of the proposed principle for the development of TIC systems for complicated reactive distillation columns.展开更多
Power plants are nonlinear and uncertain complex systems. Reliable control of superheated steam temperature is necessary to ensure high efficiency and high load-following capability in the operation of modem power pla...Power plants are nonlinear and uncertain complex systems. Reliable control of superheated steam temperature is necessary to ensure high efficiency and high load-following capability in the operation of modem power plant. A nonlinear generalized predictive controller based on neuro-fuzzy network (NFGPC) is proposed in this paper. The proposed nonlinear controller is applied to control the superheated steam temperature of a 200MW power plant. From the experiments on the plant and the simulation of the plant, much better performance than the traditional controller is obtained,展开更多
Holding temperature and holding thickness are main parameters for two-phase controlled rolling on plate mill. The optimization of holding temperature and holding thickness for pass schedule calculation of two-phase co...Holding temperature and holding thickness are main parameters for two-phase controlled rolling on plate mill. The optimization of holding temperature and holding thickness for pass schedule calculation of two-phase controlled rolling on plate mill was presented and its feature is as follows: (1) Determination of holding thickness can be automatically obtained based on the influence of mill safety limits, tracking zone length and holding time on holding thickness; (2) Determination of holding temperature can be automatically obtained and the holding time can be reduced as much as possible; (3) Algorithm can modify the holding temperature and thickness depending on slab size and product size.展开更多
A three-dimensional finite element program for thermal analysis of hydration heat in concrete structures with a plastic pipe cooling system is introduced in this paper. The program was applied to simulation of the tem...A three-dimensional finite element program for thermal analysis of hydration heat in concrete structures with a plastic pipe cooling system is introduced in this paper. The program was applied to simulation of the temperature and stress field of the Cao'e Sluice during the construction period. From the calculated results, we can find that the temperaiure and stress of concrete cooled with plastic pipes are much lower than those of concrete without pipes. Moreover, plastic pipes could not be corroded by seawater. That is to say, a good effect of temperature control and cracking prevention can be achieved, which provides a useful reference for other similar nearshore concrete projects.展开更多
The sheet size of a graphene oxide (GO) can greatly influence its electrical, optical, mechanical, electrochemical and catalytic property. It is a key challenge to how to control the sheet size during its preparatio...The sheet size of a graphene oxide (GO) can greatly influence its electrical, optical, mechanical, electrochemical and catalytic property. It is a key challenge to how to control the sheet size during its preparation in different application fields. According to our previous theoretical calculations of the effect of temperature on the oxidation process of graphene, we use Hummers method to prepare GOs with different sheet sizes by simply controlling the temperature condition in the process of the oxidation reaction of potassium permanganate (KMnO4) with graphene and the dilution process with deionized water. The results detected by transmission electron microscopy (TEM) and atomic force microscopy (AFM) show that the average sizes of GO sheets prepared at different temperatures are about 1 μm and 7 μm respectively. The ultraviolet-visible spectroscopy (UV-vis) shows that lower temperature can lead to smaller oxidation degrees of GO and less oxygen functional groups on the surface. In addition, we prepare GO membranes to test their mechanical strengths by ultrasonic waves, and we find that the strengths of the GO membranes prepared under low temperatures are considerably higher than those prepared under high temperatures, showing the high mechanical strengths of larger GO sheets. Our experimental results testify our previous theoretical calculations. Compared with the traditional centrifugal separation and chemical cutting method, the preparation process of GO by temperature control is simple and low-cost and also enables large-size synthesis. These findings develop a new method to control GO sheet sizes for large-scale potential applications.展开更多
Flue gas heat loss accounts for a significant component of theoverall heat loss for coal-fired boilers in power plants. The flue gas absorbsmore heat as the exhaust gas temperature rises, which reduces boiler efficien...Flue gas heat loss accounts for a significant component of theoverall heat loss for coal-fired boilers in power plants. The flue gas absorbsmore heat as the exhaust gas temperature rises, which reduces boiler efficiencyand raises coal consumption. Additionally, if the exhaust gas temperatureis too high, a lot of water must be used to cool the flue gas for the wetflue gas desulfurization system to function well, which has an impact onthe power plant’s ability to operate profitably. It is consequently vital totake steps to lower exhaust gas temperatures in order to increase boilerefficiency and decrease the amount of coal and water used. Desulfurizationperformance may be enhanced and water use can be decreased by reasonableflue gas characteristics at the entry. This study analyzed the unit’s energyconsumption, investment, and coal savings while proposing four couplingstrategies for regulating flue gas temperature and waste heat recovery. Agraded flue gas conditioning and waste heat recovery plan was presentedunder the condition of ensuring high desulfurization efficiency, along withthe notion of minimizing energy loss owing to energy inflow temperaturedifference. Numerical results show that the proposed methods improved thesystem performance and reduced the water consumption and regulated theboiler temperature.展开更多
In deep geological disposal of high-level nuclear waste,one of the most important subjects is to estimate long-term stability and strength of host rock under high temperature conditions caused by radioactive decay of ...In deep geological disposal of high-level nuclear waste,one of the most important subjects is to estimate long-term stability and strength of host rock under high temperature conditions caused by radioactive decay of the waste.In this paper,some experimental researches on the thermo-mechanical characteristics of soft sedimentary rock have been presented.For this reason,a new temperature-controlled triaxial compression and creep test device,operated automatically by a computer-controlled system,whose control software has been developed by the authors,was developed to conduct the thermo-mechanical tests in different thermal loading paths,including an isothermal path.The new device is proved to be able to conduct typical thermo-mechanical element tests for soft rock.The test device and the related testing method were introduced in detail.Finally,some test results have been simulated with a thermo-elasto-viscoplastic model that was also developed by the authors.展开更多
Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation...Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation with the variation of the tide.Quality control of data includes the validation of extreme values and checking of hourly values based on temporally adjacent data points,with 0.15℃/h considered a suitable threshold for detecting abnormal values.The diurnal variation amplitude of the SST data is greater in spring and summer than in autumn and winter.The diurnal variation of SST has bimodal structure on most days,i.e.,SST has a significant semidiurnal cycle.Moreover,the semidiurnal cycle of SST is negatively correlated with the tidal data from March to August,but positively correlated with the tidal data from October to January.Little correlation is detected in the remaining months because of the weak coastal offshore SST gradients.The quality control and understanding of coastal SST data are particularly relevant with regard to the validation of indirect measurements such as satellite-derived data.展开更多
基金The authors thank D.Berger,D.Hofmann and C.Kupka in IFW Dresden for helpful technical support.H.R.acknowledges funding from the DFG(Deutsche Forschungsgemeinschaft)within grant number RE3973/1-1.Q.J.,H.R.and K.N.conceived the work.With the support from N.Y.and X.J.,Q.J.and T.G.fabricated the thermoelectric films and conducted the structural and compositional characterizations.Q.J.prepared microchips and fabricated the on-chip micro temperature controllers.Q.J.and N.P.carried out the temperature-dependent material and device performance measurements.Q.J.and H.R.performed the simulation and analytical calculations.Q.J.,H.R.and K.N.wrote the manuscript with input from the other coauthors.All the authors discussed the results and commented on the manuscript.
文摘Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.
基金Supported by the National'Naturai Science Foundation of China (30970638, 21176220 and 31240054), Zhejiang Provincial Natural Science Foundation (Z13B06008) and the National Basic Research Program of China (2007CB714305).
基金supported in part by the National Natural Science Foundation of China(51977127)Shanghai Municipal Science and Technology Commission(19020500800)“Shuguang Program”(20SG52)Shanghai Education Development Foundation and Shanghai Municipal Education Commission.
文摘From the perspective of a community energy operator,a two-stage optimal scheduling model of a community integrated energy system is proposed by integrating information on controllable loads.The day-ahead scheduling analyzes whether various controllable loads participate in the optimization and investigates the impact of their responses on the operating economy of the community integrated energy system(IES)before and after;the intra-day scheduling proposes a two-stage rolling optimization model based on the day-ahead scheduling scheme,taking into account the fluctuation of wind turbine output and load within a short period of time and according to the different response rates of heat and cooling power,and solves the adjusted output of each controllable device.The simulation results show that the optimal scheduling of controllable loads effectively reduces the comprehensive operating costs of community IES;the two-stage optimal scheduling model can meet the energy demand of customers while effectively and timely suppressing the random fluctuations on both sides of the source and load during the intra-day stage,realizing the economic and smooth operation of IES.
文摘As energy efficiency and indoor comfort increasingly become key standards in modern residential and office environments,research on intelligent fan speed control systems has become particularly important.This study aims to develop a temperature-feedback-based fan speed optimization strategy to achieve higher energy efficiency and user comfort.Firstly,by analyzing existing fan speed control technologies,their main limitations are identified,such as the inability to achieve smooth speed transitions.To address this issue,a BP-PID speed control algorithm is designed,which dynamically adjusts fan speed based on indoor temperature changes.Experimental validation demonstrates that the designed system can achieve smooth speed transitions compared to traditional fan systems while maintaining stable indoor temperatures.Furthermore,the real-time responsiveness of the system is crucial for enhancing user comfort.Our research not only demonstrates the feasibility of temperature-based fan speed optimization strategies in both theory and practice but also provides valuable insights for energy management in future smart home environments.Ultimately,this research outcome will facilitate the development of smart home systems and have a positive impact on environmental sustainability.
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National Key R&D Plan Project(No.2021YFC3090102)。
文摘Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves:convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.
基金supported by China Postdoctoral Science Foundation(No.2021M702304)Shandong Provincial Natural Science Foundation Youth Fund(No.ZR2021QE260).
文摘After steam discharge in heavy oil reservoirs,the distribution of temperature,pressure,and permeability in different wells becomes irregular.Flow channels can easily be produced,which affect the sweep efficiency of the oil displacement.Previous studies have shown that the salting-out plugging method can effectively block these channels in high-temperature reservoirs,improve the suction profile,and increase oil production.In the present study,the optimal dosage of the plugging agent is determined taking into account connection transmissibility and inter-well volumes.Together with the connectivity model,a water flooding simulation model is introduced.Moreover,a non-gradient stochastic disturbance algorithm is used to obtain the optimal plugging agent dosage,which provides the basis for the high-temperature salting-out plugging agent adjustment in the field.
基金supported by the National Natural Science Foundation of China (No.50978003)the Beijing Natural Science Foundation (No.8091001)+1 种基金the Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality (No.PHR20090502)the State Key Laboratory of Urban Water Resource and Environment (No.QAK200802)
文摘A two-stage upflow anaerobic sludge blanket (UASB) and sequencing batch reactor (SBR) system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to improve the total nitrogen (TN) removal efficiency and to reduce the COD requirement for denitrification, the raw leachate with recycled SBR nitrification supematant was pumped into the first-stage UASB (UASB1) to achieve simultaneous denitrification and methanogenesis. The results showed that UASB1 played an important role in COD removal and UASB2 and SBR further enhanced the nutrient removal efficiency. When the organic loading rates of UASB1, UASB2 and SBR were 11.95, 1.63 and 1.29 kg COD/(m^3.day), respectively, the total COD removal efficiency of the whole system reached 96.7%. The SBR acted as the real undertaker for NH4^+-N removal due to aerobic nitrification. The system obtained about 99.7% of NH4^+-N removal efficiency at relatively low temperature (14.9-10.9℃). More than 98.3% TN was removed through complete denitrification in UASB 1 and SBR. In addition, temperature had a significant effect on the rates of nitrification and denitrification rather than the removal of TN and NH4^+-N once the complete nitrification and denitrification were achieved.
基金supported by the National Natural Science Foundation of China (No.50174031)
文摘To predict and optimize the temperature distribution of slab continuous casting in steady operational state, a three-dimensional model (named "offline model") based on the heat transfer and solidification theories was developed. Both heat transfer and flux distribution characteristics of the nozzle sprays on the slab were considered, and the complicated boundary conditions, such as spray cooling, natural convection, thermal radiation as well as contact cooling of individual rolls were involved in the model. By using the calibrated caster dependent model factors, the calculated temperature and shell thickness accorded well with the measured. Furthermore, a dynamic secondary water cooling control system was also developed on the basis of a two-dimensional transient heat transfer model (named "online model") and incremental PID control algorithm to reduce slab surface temperature fluctuation in unsteady state. Compared with the traditional spray table control method, the present online model and dynamic PID control demonstrate a higher capability and flexibility to adjust cooling water flowrate and reduce slab surface temperature fluctuation when the casting speed is changed.
基金Sponsored by the Fundamental Research Funds for Heilongjiang Postdoctoral Grant(Grant No.LRB11-334)Natural Science Foundation of Heilongjiang Province(Grant No.QC2013C035)+1 种基金Heilongjiang Province Education Department of Science and Technology Research Foundation(Grant No.12533014)the Foundamental Research Funds for the Central Universities(Grant No.2572014CB13)
文摘A design method of an intelligent temperature control system based on single-chip microcomputer is presented in this paper. The intelligent temperature control system is divided into four parts: monitor,heater,controlled process and feedback loop. Among them,the temperature detection circuit is designed with the conductivity of water by sensor detection. The optical coupler MOC3041 is used to implement the power control circuit,whose control object is 1 kW electric heater with the 220 V alternating current power; keyboard and display circuit SMC1602A include four buttons and LCD display to achieve human-computer interaction; Based on single-chip system STC89C52,the sensor signal and keyboard set target temperature are compared to the power automatically in order to finish the water temperature control. Through the static and dynamic data testing,the results show that the proposed method provides an effective way to realize the real-time acquisition and control of temperature.
基金It was supported by the National Natural Science Foundation of China (No. 59835170).
文摘A temperature control system of 31m vertical forced air-circulation quench furnace is proposed, which is a kind of equipment critical for thermal treatment of aluminum alloy components that are widely used in aerospace industry. For the effective operation of the furnace, it is essential to analyze the radial temperature distribution of the furnace. A set of thermodynamic balance equations modeling is established firsdy. By utilizing the numerical analysis result to modify the temperature measurements, the control accuracy and precision of the temperature are truly guaranteed. Furthermore, the multivariable decoupling self-learning PID control algorithm based on the characteristics of strong coupling between the multi-zones in the large-scaled furnace is implemented to ensure the true homogeneity of the axial temperature distribution. Finally, the redundant structure composed of industrial control computers and touch panels leads to great improvement of system reliability.
基金Supported by the National Natural Science Foundation of China(21376018,21576014,21676011,21808007,and 21878011)the Fundamental Research Funds for the Central Universities(ZY1837)China Postdoctoral Science Foundation(2017M620587)
文摘Temperature inferential control (TIC) is studied for a reactive distillation column with double reactive sections (RDC-DRSs) processing a hypothetical two-stage consecutive reversible reaction (A + B■C + D, C + B■E + D with αD > αB > αC > αA > αE). Because of the complicated dynamic behaviors, the controlled stages by sensitivity analysis lead to great steady-state deviations (SSDs) in top and bottom product purities. Since TIC involves considerably reduced settling times in comparison with direct composition control, small SSDs in product qualities correspond generally to small transient deviations (TDs) in product qualities. An objective function that measures SSDs in product qualities is formulated to represent the performance of a TIC system and an iterative procedure is devised to search for the best control configuration. The application of the procedure to the RDC-DRS gives considerably suppressed TDs and SSDs in top and bottom product qualities as compared with the one by sensitivity analysis. The method is simpler in principle and less computationally intensive than the current practice. These striking outcomes show the effectiveness of the proposed principle for the development of TIC systems for complicated reactive distillation columns.
基金This work was supported by the Natural Science Foundation of Beijing (No. 4062030)National Natural Science Foundation of China (No. 50576022,69804003)Scientific Research Common Program of Beijing Municipal Commission of Education (KM200611232007).
文摘Power plants are nonlinear and uncertain complex systems. Reliable control of superheated steam temperature is necessary to ensure high efficiency and high load-following capability in the operation of modem power plant. A nonlinear generalized predictive controller based on neuro-fuzzy network (NFGPC) is proposed in this paper. The proposed nonlinear controller is applied to control the superheated steam temperature of a 200MW power plant. From the experiments on the plant and the simulation of the plant, much better performance than the traditional controller is obtained,
文摘Holding temperature and holding thickness are main parameters for two-phase controlled rolling on plate mill. The optimization of holding temperature and holding thickness for pass schedule calculation of two-phase controlled rolling on plate mill was presented and its feature is as follows: (1) Determination of holding thickness can be automatically obtained based on the influence of mill safety limits, tracking zone length and holding time on holding thickness; (2) Determination of holding temperature can be automatically obtained and the holding time can be reduced as much as possible; (3) Algorithm can modify the holding temperature and thickness depending on slab size and product size.
基金supported by the National Natural Science Foundation of China (Grant No. 50779010)
文摘A three-dimensional finite element program for thermal analysis of hydration heat in concrete structures with a plastic pipe cooling system is introduced in this paper. The program was applied to simulation of the temperature and stress field of the Cao'e Sluice during the construction period. From the calculated results, we can find that the temperaiure and stress of concrete cooled with plastic pipes are much lower than those of concrete without pipes. Moreover, plastic pipes could not be corroded by seawater. That is to say, a good effect of temperature control and cracking prevention can be achieved, which provides a useful reference for other similar nearshore concrete projects.
基金supported by the National Natural Science Foundation of China(Grant Nos.41473090,41430644,11675098,41373098,41430644,and 21490585)
文摘The sheet size of a graphene oxide (GO) can greatly influence its electrical, optical, mechanical, electrochemical and catalytic property. It is a key challenge to how to control the sheet size during its preparation in different application fields. According to our previous theoretical calculations of the effect of temperature on the oxidation process of graphene, we use Hummers method to prepare GOs with different sheet sizes by simply controlling the temperature condition in the process of the oxidation reaction of potassium permanganate (KMnO4) with graphene and the dilution process with deionized water. The results detected by transmission electron microscopy (TEM) and atomic force microscopy (AFM) show that the average sizes of GO sheets prepared at different temperatures are about 1 μm and 7 μm respectively. The ultraviolet-visible spectroscopy (UV-vis) shows that lower temperature can lead to smaller oxidation degrees of GO and less oxygen functional groups on the surface. In addition, we prepare GO membranes to test their mechanical strengths by ultrasonic waves, and we find that the strengths of the GO membranes prepared under low temperatures are considerably higher than those prepared under high temperatures, showing the high mechanical strengths of larger GO sheets. Our experimental results testify our previous theoretical calculations. Compared with the traditional centrifugal separation and chemical cutting method, the preparation process of GO by temperature control is simple and low-cost and also enables large-size synthesis. These findings develop a new method to control GO sheet sizes for large-scale potential applications.
文摘Flue gas heat loss accounts for a significant component of theoverall heat loss for coal-fired boilers in power plants. The flue gas absorbsmore heat as the exhaust gas temperature rises, which reduces boiler efficiencyand raises coal consumption. Additionally, if the exhaust gas temperatureis too high, a lot of water must be used to cool the flue gas for the wetflue gas desulfurization system to function well, which has an impact onthe power plant’s ability to operate profitably. It is consequently vital totake steps to lower exhaust gas temperatures in order to increase boilerefficiency and decrease the amount of coal and water used. Desulfurizationperformance may be enhanced and water use can be decreased by reasonableflue gas characteristics at the entry. This study analyzed the unit’s energyconsumption, investment, and coal savings while proposing four couplingstrategies for regulating flue gas temperature and waste heat recovery. Agraded flue gas conditioning and waste heat recovery plan was presentedunder the condition of ensuring high desulfurization efficiency, along withthe notion of minimizing energy loss owing to energy inflow temperaturedifference. Numerical results show that the proposed methods improved thesystem performance and reduced the water consumption and regulated theboiler temperature.
文摘In deep geological disposal of high-level nuclear waste,one of the most important subjects is to estimate long-term stability and strength of host rock under high temperature conditions caused by radioactive decay of the waste.In this paper,some experimental researches on the thermo-mechanical characteristics of soft sedimentary rock have been presented.For this reason,a new temperature-controlled triaxial compression and creep test device,operated automatically by a computer-controlled system,whose control software has been developed by the authors,was developed to conduct the thermo-mechanical tests in different thermal loading paths,including an isothermal path.The new device is proved to be able to conduct typical thermo-mechanical element tests for soft rock.The test device and the related testing method were introduced in detail.Finally,some test results have been simulated with a thermo-elasto-viscoplastic model that was also developed by the authors.
基金The Open Fund of State Key Laboratory of Satellite Ocean Environment Dynamics under contract No.SOED1402the Youth Science and Technology Foundation of East China Sea Branch,SOA under contract No.201624
文摘Sea surface temperature(SST)data obtained from coastal stations in Jiangsu,China during 20102014 are quality controlled before analysis of their characteristic semidiurnal and seasonal cycles,including the correlation with the variation of the tide.Quality control of data includes the validation of extreme values and checking of hourly values based on temporally adjacent data points,with 0.15℃/h considered a suitable threshold for detecting abnormal values.The diurnal variation amplitude of the SST data is greater in spring and summer than in autumn and winter.The diurnal variation of SST has bimodal structure on most days,i.e.,SST has a significant semidiurnal cycle.Moreover,the semidiurnal cycle of SST is negatively correlated with the tidal data from March to August,but positively correlated with the tidal data from October to January.Little correlation is detected in the remaining months because of the weak coastal offshore SST gradients.The quality control and understanding of coastal SST data are particularly relevant with regard to the validation of indirect measurements such as satellite-derived data.