The first MT monitoring profile with initial shape both at home and abroad has been built in the northern margin of the Qinghai-Tibet Plateau. Based on MT data observed before and after the eight earthquakes of M=5-7 ...The first MT monitoring profile with initial shape both at home and abroad has been built in the northern margin of the Qinghai-Tibet Plateau. Based on MT data observed before and after the eight earthquakes of M=5-7 from 1988 to 1992,a new parameter-mean resistivity has been introduced. The results show that indicates not only the major feature of decreasing-increasing and recovering to notmal value, but also synchronism of phase or the variation in a large area, 'lead or delay' among different small areas and the amplitude decreasing with the increase of the distance from the epicenter. Two characters mentioned above might correspond to reginal field precursor of the tectonic generating earthquake and field precursor of the tectonic kinematics. This paper analyses the errors of observed data and the cause of variation. The MT profile optimum parameter system consists of parameter,apparent resistivity,twisting degree and the principal-axis azimuth which might provide quantitative criterion for the physical prooes of the great destructive earthquake and moderate and short-term earthquake prediction.展开更多
It is expounded that h2/ is the Reynolds number form of thrust bearings and effects of the centrifugal forees can be judged by its magnitude. Three methods improving the configuration of pads are given out to...It is expounded that h2/ is the Reynolds number form of thrust bearings and effects of the centrifugal forees can be judged by its magnitude. Three methods improving the configuration of pads are given out to overcome the haimful influence of the centrifugal forees on the performance of bearings, and the optimized parameters for three kinds of high一speed thrust bearings are provi- ded by solving the varying一viscositied three一dimensional Reynolds equation.展开更多
The steepest descent(or ascent)search is employed for finding optimum diffusion coefficients in T42L9G model,with a view to improving the model's computational stability or prediction accuracy.The method of the st...The steepest descent(or ascent)search is employed for finding optimum diffusion coefficients in T42L9G model,with a view to improving the model's computational stability or prediction accuracy.The method of the steepest descent search is first described,in which the golden section search is chosen as the fundamental one- dimensional search used in the multi-dimentional steepest descent search,and then the optimization of the dif- fusion coefficients is described.展开更多
In this paper</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span&g...In this paper</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> a literature review on thermocline storage performance fo</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">r Concentrating Solar Power (CSP) plant storage systems ha</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">been conducted. The efficiency of materials to store heat depend</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> on the storage process like sensible heat storage, latent heat storage and thermochemical one and also on their properties. This study has been focused on sensible heat storage materials especially thermocline storage system (DMT) using eco-materials which has a high potentiality (35%) to reduce CSP cost. There is a possibility to use natural rocks, industry waste and to develop also materials for a thermocline storage within a bed called packed bed using one tank. The thermal storage materials should have some optimum parameters (particle diameter less than 2 </span><span style="font-family:Verdana;">cm and good thermo-physical properties) to achieve better thermal storage performance (thermal cycle efficiency, extraction factor). However, the size and the shape of natural rocks are uncontrollable (big diameter) and can </span><span style="font-family:Verdana;">drive to thermocline degradation, catastrophic thermal ratcheting and poor thermal stratification due to the variability of the storage system porosity and the stress on the storage tank wall. Also a better thermal storage efficiency is achievable at low velocity and with good thermo-physical properties of the HTF. The ratio H/D, the height, the porosity, the shape and the position of the tank should be optimized to increase the storage efficiency.展开更多
In this paper, the influence of plasma arc powder surfacing technical parameters on the property of layer is defined using the orthogonal design. By the orthogonal polynomial regression, when plasma arc powder surfaci...In this paper, the influence of plasma arc powder surfacing technical parameters on the property of layer is defined using the orthogonal design. By the orthogonal polynomial regression, when plasma arc powder surfacing is used on the surface of the X65 steel plate with the Fe-07 alloy powder, the optimum technical parameters are the following: I=180~190 A , G=41.5 g/min , v=102 mm/min , T_0=350 ℃ , Q_l=280 L/h , Q_s=400 L/h . Further, analysis of the cracking test data showed that the cracking preheat temperature is 350 ℃ .展开更多
The horizontal diffusion coefficients of the operational model (T42L9) in numerical weather prediction are optimized by the steepest descent search of multi-dimensional optimization. In order to improve prediction acc...The horizontal diffusion coefficients of the operational model (T42L9) in numerical weather prediction are optimized by the steepest descent search of multi-dimensional optimization. In order to improve prediction accuracy in low latitudes, the optimum horizontal diffusion coefficients are chosen, with changing variation of the basic diffusion coefficient with the passage of time, and later forecasts are also made better. In view of the averages of forecast verifications of 9 cases, the forecasts with optimum diffusion coefficients are an improvement on operational forecasts. It means that the forecasts are got much better with optimum values of some important parameters by optimization in numerical weather prediction.展开更多
Proportional-Integral-Derivative control system has been widely used in industrial applications.For uncertain and unstable systems,tuning controller parameters to satisfy the process requirements is very challenging.I...Proportional-Integral-Derivative control system has been widely used in industrial applications.For uncertain and unstable systems,tuning controller parameters to satisfy the process requirements is very challenging.In general,the whole system’s performance strongly depends on the controller’s efficiency and hence the tuning process plays a key role in the system’s response.This paper presents a robust optimal Proportional-Integral-Derivative controller design methodology for the control of unstable delay system with parametric uncertainty using a combination of Kharitonov theorem and genetic algorithm optimization based approaches.In this study,the Generalized Kharitonov Theorem(GKT)for quasi-polynomials is employed for the purpose of designing a robust controller that can simultaneously stabilize a given unstable second-order interval plant family with time delay.Using a constructive procedure based on the Hermite-Biehler theorem,we obtain all the Proportional-Integral-Derivative gains that stabilize the uncertain and unstable second-order delay system.Genetic Algorithms(GAs)are utilized to optimize the three parameters of the PID controllers and the three parameters of the system which provide the best control that makes the system robust stable under uncertainties.Specifically,the method uses genetic algorithms to determine the optimum parameters by minimizing the integral of time-weighted absolute error ITAE,the Integral-Square-Error ISE,the integral of absolute error IAE and the integral of time-weighted Square-Error ITSE.The validity and relatively effortless application of presented theoretical concepts are demonstrated through a computation and simulation example.展开更多
文摘The first MT monitoring profile with initial shape both at home and abroad has been built in the northern margin of the Qinghai-Tibet Plateau. Based on MT data observed before and after the eight earthquakes of M=5-7 from 1988 to 1992,a new parameter-mean resistivity has been introduced. The results show that indicates not only the major feature of decreasing-increasing and recovering to notmal value, but also synchronism of phase or the variation in a large area, 'lead or delay' among different small areas and the amplitude decreasing with the increase of the distance from the epicenter. Two characters mentioned above might correspond to reginal field precursor of the tectonic generating earthquake and field precursor of the tectonic kinematics. This paper analyses the errors of observed data and the cause of variation. The MT profile optimum parameter system consists of parameter,apparent resistivity,twisting degree and the principal-axis azimuth which might provide quantitative criterion for the physical prooes of the great destructive earthquake and moderate and short-term earthquake prediction.
文摘It is expounded that h2/ is the Reynolds number form of thrust bearings and effects of the centrifugal forees can be judged by its magnitude. Three methods improving the configuration of pads are given out to overcome the haimful influence of the centrifugal forees on the performance of bearings, and the optimized parameters for three kinds of high一speed thrust bearings are provi- ded by solving the varying一viscositied three一dimensional Reynolds equation.
文摘The steepest descent(or ascent)search is employed for finding optimum diffusion coefficients in T42L9G model,with a view to improving the model's computational stability or prediction accuracy.The method of the steepest descent search is first described,in which the golden section search is chosen as the fundamental one- dimensional search used in the multi-dimentional steepest descent search,and then the optimization of the dif- fusion coefficients is described.
文摘In this paper</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> a literature review on thermocline storage performance fo</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">r Concentrating Solar Power (CSP) plant storage systems ha</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">been conducted. The efficiency of materials to store heat depend</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> on the storage process like sensible heat storage, latent heat storage and thermochemical one and also on their properties. This study has been focused on sensible heat storage materials especially thermocline storage system (DMT) using eco-materials which has a high potentiality (35%) to reduce CSP cost. There is a possibility to use natural rocks, industry waste and to develop also materials for a thermocline storage within a bed called packed bed using one tank. The thermal storage materials should have some optimum parameters (particle diameter less than 2 </span><span style="font-family:Verdana;">cm and good thermo-physical properties) to achieve better thermal storage performance (thermal cycle efficiency, extraction factor). However, the size and the shape of natural rocks are uncontrollable (big diameter) and can </span><span style="font-family:Verdana;">drive to thermocline degradation, catastrophic thermal ratcheting and poor thermal stratification due to the variability of the storage system porosity and the stress on the storage tank wall. Also a better thermal storage efficiency is achievable at low velocity and with good thermo-physical properties of the HTF. The ratio H/D, the height, the porosity, the shape and the position of the tank should be optimized to increase the storage efficiency.
文摘In this paper, the influence of plasma arc powder surfacing technical parameters on the property of layer is defined using the orthogonal design. By the orthogonal polynomial regression, when plasma arc powder surfacing is used on the surface of the X65 steel plate with the Fe-07 alloy powder, the optimum technical parameters are the following: I=180~190 A , G=41.5 g/min , v=102 mm/min , T_0=350 ℃ , Q_l=280 L/h , Q_s=400 L/h . Further, analysis of the cracking test data showed that the cracking preheat temperature is 350 ℃ .
文摘The horizontal diffusion coefficients of the operational model (T42L9) in numerical weather prediction are optimized by the steepest descent search of multi-dimensional optimization. In order to improve prediction accuracy in low latitudes, the optimum horizontal diffusion coefficients are chosen, with changing variation of the basic diffusion coefficient with the passage of time, and later forecasts are also made better. In view of the averages of forecast verifications of 9 cases, the forecasts with optimum diffusion coefficients are an improvement on operational forecasts. It means that the forecasts are got much better with optimum values of some important parameters by optimization in numerical weather prediction.
文摘Proportional-Integral-Derivative control system has been widely used in industrial applications.For uncertain and unstable systems,tuning controller parameters to satisfy the process requirements is very challenging.In general,the whole system’s performance strongly depends on the controller’s efficiency and hence the tuning process plays a key role in the system’s response.This paper presents a robust optimal Proportional-Integral-Derivative controller design methodology for the control of unstable delay system with parametric uncertainty using a combination of Kharitonov theorem and genetic algorithm optimization based approaches.In this study,the Generalized Kharitonov Theorem(GKT)for quasi-polynomials is employed for the purpose of designing a robust controller that can simultaneously stabilize a given unstable second-order interval plant family with time delay.Using a constructive procedure based on the Hermite-Biehler theorem,we obtain all the Proportional-Integral-Derivative gains that stabilize the uncertain and unstable second-order delay system.Genetic Algorithms(GAs)are utilized to optimize the three parameters of the PID controllers and the three parameters of the system which provide the best control that makes the system robust stable under uncertainties.Specifically,the method uses genetic algorithms to determine the optimum parameters by minimizing the integral of time-weighted absolute error ITAE,the Integral-Square-Error ISE,the integral of absolute error IAE and the integral of time-weighted Square-Error ITSE.The validity and relatively effortless application of presented theoretical concepts are demonstrated through a computation and simulation example.