Meta-lens are a new type of planar optical element that can flexibly manipulate the phase, polarization and amplitude of the beam, and are currently receiving a great deal of attention as they are easier to process an...Meta-lens are a new type of planar optical element that can flexibly manipulate the phase, polarization and amplitude of the beam, and are currently receiving a great deal of attention as they are easier to process and manufacture. Off-axis meta-lens are a special type of meta-lens with a certain degree of dispersion that can be used as a beam-splitting element, providing a unique and feasible way to realize micro-miniature instruments. We analyze the effects of different numerical apertures and off-axis angles on the spectral resolution, focusing efficiency and simulation results of off-axis meta-lens to provide ideas for subsequent research and application of off-axis meta-lens. A number of off-axis meta-lens with parameters NA = 0.408 α = 13°, NA = 0.18 α = 13°<sup></sup> and NA = 0.408 α = 20° were simulated through Lumerical software. The results show that the off-axis angle is related to the resolution;the larger the angle, the better the spectral resolution but the lower the focusing efficiency;when the numerical aperture is smaller, the smaller the coverage of the phase distribution, which will lead to a larger deviation between simulation and theory. The designer needs to balance the numerical aperture, off-axis angle and other parameters reasonably according to the requirements in order to achieve the desired effect. The findings of this study have important reference values for the theoretical analysis of off-axis meta-lens and the design of parameters in practical applications. .展开更多
The teleconnection distribution characteristics of sea surface temperature (SST) over the India Ocean and the precipitation during rainy season in China were studied by using the methods of EOF and CCA. The results in...The teleconnection distribution characteristics of sea surface temperature (SST) over the India Ocean and the precipitation during rainy season in China were studied by using the methods of EOF and CCA. The results indicate that the change of SST field will affect the change of rain belt during rainy seasons in China, and greatly affect the precipitation in northwest and southwest China, the Yangzi and Yellow River downstream basins. Strong signal phenomena of SSTA over India Ocean were revealed that showed the anoma-lous distribution of drought and flood in China. It shows that the precipitation during rainy seasons in China may be forecast by analyzing SST distribution characteristics over the India Ocean.展开更多
In general, the location of traffic accidents is described as an address with text, so they are difficult to display on the map. The paper discusses how to utilize the geocoding technology and VRS-GPS positioning tech...In general, the location of traffic accidents is described as an address with text, so they are difficult to display on the map. The paper discusses how to utilize the geocoding technology and VRS-GPS positioning technology to record the traffic accidents with Geo-spatial information. Based on the spatial relationship between traffic accidents and road network elements, two-way association relationship is defined by spatial relationship computation. Then the paper presents the method which takes the potential of reducing accidents as an index to extract the black spots. Finally, in the discussion, the association relationship between black spots and traffic attributes is used to analyze the factors that resulting in traffic accidents.展开更多
When exploring the temporal and spatial change law of ocean environment, the most common method used is using smaller-scale observed data to derive the change law for a larger-scale system. For instance, using 30-year...When exploring the temporal and spatial change law of ocean environment, the most common method used is using smaller-scale observed data to derive the change law for a larger-scale system. For instance, using 30-year observation data to derive 100-year return period design wave height. Therefore, the study of inherent self-similarity in ocean hydrological elements becomes increasingly important to the study of multi-year return period design wave height derivation. In this paper, we introduced multifractal to analyze the statistical characteristics of wave height series data observed from oceanic hydrological station. An improvement is made to address the existing problems of the multifractal detrended fluctuation analysis (MF-DFA) method, where trend function showed a discontinuity between intervals. The improved MFDFA method is based on signal mode decomposition, replacing piecewise polynomial fitting used in the original method. We applied the proposed method to the wave height data collected at Chaolian Island, Shandong, China, from 1963 to 1989 and was able to conclude the wave height sequence presented weak multi-fractality. This result provided strong support to the past research on the derivation of multi-year return period design wave height with observed data. Moreover, the new method proposed in this paper also provides a new perspective to explore the intrinsic characteristic of data.展开更多
The characteristic study of powder quartz is the basis of the comprehensive utilization of quartz powder resources.In this paper,the characteristic of a powder quartz mine in Yunnan Province is analyzed, through the a...The characteristic study of powder quartz is the basis of the comprehensive utilization of quartz powder resources.In this paper,the characteristic of a powder quartz mine in Yunnan Province is analyzed, through the analysis of X-ray diffraction,chemical composition,SEM analysis of the different samples those purified to different extent,etc.The results indicated that the powder quartz’s whiteness is 81.4, and the main mineral compositions are quartz,clay mineral(mostly kaolinite and illite) and a little of feldspar,and the content of quartz is about 85%。展开更多
The results of characteristic comparison and principal component analysis showed that the major .characteristics of sesame varieties in Henan province were improved in the past decades. The sesame breeding works in th...The results of characteristic comparison and principal component analysis showed that the major .characteristics of sesame varieties in Henan province were improved in the past decades. The sesame breeding works in the province were focused on the collection and the screening of the native germplasms from 1950 to 1969 and the mean values of the variety characteristics were the lowest. In 1970s,the pedigree breeding was mainly conducted,which resulted in the release of varieties of various types with better traits. During 1980s,the hybridization breeding was carried out dominantly with the varieties possessing fine traits. Since 1990,there were no better varieties released. To make new progresses,it is essential to renew the breeding method and at the same time to introduce and create special germplasms to widen the genetic background.展开更多
The Asia Pacific Economic Cooperation(APEC)comprises of the world’s largest producers and consumers of energy,accounting for 60.3%of primary energy supply,50.0%of final energy consumption,and 63.0%of electricity gene...The Asia Pacific Economic Cooperation(APEC)comprises of the world’s largest producers and consumers of energy,accounting for 60.3%of primary energy supply,50.0%of final energy consumption,and 63.0%of electricity generation worldwide in 2016.This study discusses the primary energy supply and final energy consumption situation of the APEC and analyzes the characteristics of electricity in terms of its generation structure based on fuel,consumption by the end-use sector,access to electricity,and so on.The renewable energy and electricity generation projections up to 2030 based on trends in the APEC are also assessed.It is seen that electricity in final energy consumption has been on an upward trend,with an average annual growth rate of about 4.8%during 2006–2016,in 2016,its share reached 24.3%.The industry sector consumes the largest share of electricity,accounting for about 45.5%in 2016.Coal supply and consumption peaked in 2011 and then began to decline,while renewable energy has been on an upward trend,with its primary energy supply share increasing from 4.80%in 2010 to 6.29%in 2016.Solar photovoltaic and onshore wind power are on the verge of costing less than the operating cost of existing coal-fired plants in 2018.In the APEC’s target scenario in which renewable energy is doubled,the predicted net growth from 2017 to 2030 of solar,wind,and hydro power is about 963,497,and 157 GW,respectively,and to reach this target,the APEC economies need to accelerate renewable energy development.展开更多
Based on the phase change material (PCM) thermal characteristic,some testing methods such as differential scanning calorimeter (DSC) etc were used to select the low melting mixture of capric and lauric acid as PCM of ...Based on the phase change material (PCM) thermal characteristic,some testing methods such as differential scanning calorimeter (DSC) etc were used to select the low melting mixture of capric and lauric acid as PCM of phase change wallboard (PCW). The PCW room was established,and some contrast analysis of the storage and exchange thermal characteristic of PCW room and ordinary wall room were made under different conditions. The results show that the fluctuation of indoor air temperature in PCW room is smaller than that in ordinary room obviously. The exchange energy of PCM room with outdoor is less than that of ordinary wall room. In the winter condition,PCW room utilizes valley period electricity to storage energy in the night,while releases at peak period electricity in daytime,which can divert 40% of peak load. In the summer condition,PCW room can reduce the peak cooling load by 25% compared with ordinary wall room.展开更多
Characteristic analysis of transient electromagnetic disturbance data is very important. In this paper, the time-domain and frequency-domain characteristics of transient electromagnetic disturbance caused by switching...Characteristic analysis of transient electromagnetic disturbance data is very important. In this paper, the time-domain and frequency-domain characteristics of transient electromagnetic disturbance caused by switching operations in substations are analyzed. Two methods are adopted in time-domain analysis. One method is histogram and the other one is normality test. An appropriate procedure for the normality test is proposed. Furthermore, the method used in frequency- domain analysis is to obtain overall envelope. These statistical characteristic analysis methods are showed to be of great value in analyses of the measured samples. The simulation results showed that these methods are effective.展开更多
This paper analyses the transient characteristics of high temperature CMOS inverters and gate circuits, and gives the computational formulas of their rise time, fall time and delay time. It may be concluded that the t...This paper analyses the transient characteristics of high temperature CMOS inverters and gate circuits, and gives the computational formulas of their rise time, fall time and delay time. It may be concluded that the transient characteristics of CMOS inverters and gate circuits deteriorate due to the reduction of carrier mobilities and threshold voltages of MOS transistors and the increase of leakage currents of MOS transistors drain terminal pn junctions. The calculation results can explain the experimental phenomenon.展开更多
Objective(s): Laryngeal inflammations lead to voice disorders. Medical conditions such as chronic laryngitis, gastroesophageal reflux, laryngopharyngeal reflux, Reinke edema and/or vocal folds hemorrhage, result in di...Objective(s): Laryngeal inflammations lead to voice disorders. Medical conditions such as chronic laryngitis, gastroesophageal reflux, laryngopharyngeal reflux, Reinke edema and/or vocal folds hemorrhage, result in diverse symptoms including chronic cough, throat cleaning and dysphonia (e.g. hoarseness). In turn, the dysphonic symptoms can be evaluated via subjective and objective procedures. The objective procedures usually include self-perceived questionnaires like the Voice Handicap Index (VHI). Studies reported that VHI can distinguish objectively dysphonic and non-dysphonic populations using the cut-off points of Receiver Operating Characteristic Curves. The purpose of this study was to calculate the cut-off points for individuals exhibiting voice symptoms which had been developed from laryngeal inflammatory diseases in Greece. Methods: One hundred and twelve participants (90 non-dysphonic and 22 dysphonic) filled in the Hellenic Voice Handicap Index (VHI) and the Greek translated version of Voice Evaluation Template (VEF) were administrated. All subjects were evaluated by an Otolaryngologist and a Speech-Language Pathologist. Results: The group with voice disorders exhibited higher VHI scores (in total and in its 3 subdomains) compared to non-dysphonic subgroup. Statistical significant differences were found for all VHI’s total cut-off point of 19.50 (sensitivity: 0.882, 1-specificity: 0.011) and for its three subdomains [functional 6.50 (sensitivity = 0.636, and 1-specificity = 0.022);physical 9.50 (sensitivity = 0.636, and 1-specificity = 0.000);emotional 6.50 (sensitivity = 0.455, and 1-specificity = 0.133)]. Conclusion: The preliminary results showed that VHI could discriminate individuals having voice disorders from laryngeal inflammations. The Voice Handicap Index can be used as a primary health care tool and a self-monitoring procedure in acute and sub-acute phases of the laryngeal inflammation.展开更多
Electric vehicle, as a clean energy industry, is an important branch. Electric vehicles not only are the energy of the electric user, but also can be used as mobile and distributed energy storage unit to the grid. As ...Electric vehicle, as a clean energy industry, is an important branch. Electric vehicles not only are the energy of the electric user, but also can be used as mobile and distributed energy storage unit to the grid. As a precondition of safety operation for power grid, studies of EVs’ charging load characteristics is also the theoretical basis of intelligent scheduling EVs charging orderly. This paper assesses the future of the electric vehicles development prospects, and secondly establishes a charging model of a single EV. Then, considering stochastic distribution of the initial state-of-charge (SOC0) and the arriving time of the vehicles, a cluster model of the charging station is proposed. Meanwhile, the paper from the types and charging mode of electric vehicles analyzes the behavior of EV. Finally, an example simulation is validated.展开更多
Dynamic capacity increase in high voltage electric power transmission line is currently the most economical method for solving electric power transmission bottleneck nowadays. DS18B20 temperature sensor is applied to ...Dynamic capacity increase in high voltage electric power transmission line is currently the most economical method for solving electric power transmission bottleneck nowadays. DS18B20 temperature sensor is applied to the dynamic capacity increase of high voltage transmission lines to measure the conductor temperature and ambient temperature. The paper is focused on the experiment of DS18B20 both in the laboratory and outside. From the result of the lab temperature measurement data analysis, using 4 DS18B20’s is the most suitable plan, considering both accuracy and economical efficiency. In the experiment outside, we get four groups of conductor (uncharged) temperature and four groups of ambient temperature. The data proved that DS18B20 has good stability, and small measurement error. It is suitable for measuring the temperature of conductor and ambient in dynamic capacity increase, and helpful to improve the accuracy of the calculation of capacity increasing.展开更多
This paper looks at the development of a class of Exponential Compact Higher Order (ECHO) schemes and attempts to comprehend their behaviour by introducing different combinations of discrete source function and its de...This paper looks at the development of a class of Exponential Compact Higher Order (ECHO) schemes and attempts to comprehend their behaviour by introducing different combinations of discrete source function and its derivatives. The characteristic analysis is performed for one-dimensional schemes to understand the efficiency of the scheme and a similar analysis has been introduced for higher dimensional schemes. Finally, the developed schemes are used to solve several example problems and compared the error norms and rates of convergence.展开更多
This thesis gives overview of the connotation of rural spatial structure,indicating 4 kinds of elements,namely nodus,passage,region and flow.Their spatial arrangement and interaction lead to the corresponding rural sp...This thesis gives overview of the connotation of rural spatial structure,indicating 4 kinds of elements,namely nodus,passage,region and flow.Their spatial arrangement and interaction lead to the corresponding rural spatial structure.This thesis also offers panorama of the related theoretical progress of intra-county and rural areas,indicating that the research theories of regional spatial structure at present,mainly focus on macroscopic region or urban space,but there is shortage of researches on county spatial structure,especially microscopic rural spatial structure.On such basis,4 kinds of theoretical models and characteristics of regional spatial structure have been introduced.We build analysis index system of rural structural elements on the basis of 4 elements,and conduct rural spatial structural analysis,taking Jinhu County as an example.The result shows that rural spatial structure in Jinhu County is still at stage of nucleus-cluster development and rural system is not so sound.In addition,the passage network system of infrastructure has not taken shape,and county economy presents diseconomy of scale.The spatial interaction and association among towns in Jinhu County are weak.The characteristic analysis model of spatial structure in this research can objectively reflect regional characteristic of spatial structure.展开更多
In this paper, the mathematical model of solenoid valve in the fuel injection system of gas engine is built. Simulation software Matlab/Simulink are employed to analyze the impact which the voltage, number of the coil...In this paper, the mathematical model of solenoid valve in the fuel injection system of gas engine is built. Simulation software Matlab/Simulink are employed to analyze the impact which the voltage, number of the coil turns and air gap width may produce to the open and close characteristics of the solenoid valve. The ideal response characteristics are got through the calculation. An optimal scheme which satisfies the operation requirements is put forward. The driving voltage and maintaining voltage are set as 90 V and 21 V;number of the coil turns is 30 N;air gap is determined as 0.6 mm;the opening and closing time are respectively 0.98 ms and 0.8 ms. This paper can be used as a reference for the design of the solenoid valve.展开更多
In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further i...In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further improve its working performance,a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect.Next,by using the current theoretical model,some numerical analyses and discussion about the surface effect,the corresponding critical thickness of the nanoplate,and the distributions of the physical fields(including the electron concentration perturbation,the electric potential,the electric field,the average electric displacement,the effective polarization charge density,and the total charge density)under different initial state electron concentrations,as well as their active manipulation via some external magnetic field,pre-stress,and temperature stimuli,are performed.Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment,this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect,but also assists the design of a series of multiferroic PS nanodevices.展开更多
The electrostatic discharge(ESD)phenomenon is very common,in daily life,many places will appear ESD phenomenon.However,ESD is a potential hazard for integrated circuits.This paper analyzes the ESD protection design an...The electrostatic discharge(ESD)phenomenon is very common,in daily life,many places will appear ESD phenomenon.However,ESD is a potential hazard for integrated circuits.This paper analyzes the ESD protection design and characteristics of advanced process integrated circuits,and puts forward personal views combined with experience,hoping to bring help to the people who pay attention to the ESD protection of integrated circuits.展开更多
[Objective]The research aimed to analyze characteristics of atmospheric electric field in polluted area. [Method] By using data of atmospheric electric field meter in Taiyuan in 2009,daily and annual changes of atmosp...[Objective]The research aimed to analyze characteristics of atmospheric electric field in polluted area. [Method] By using data of atmospheric electric field meter in Taiyuan in 2009,daily and annual changes of atmospheric electric field in Taiyuan were analyzed. [Result]Atmospheric electric field intensity in Taiyuan was higher than that in other areas. Daily change was double-peak double-valley type. The first highest value appeared at nightfall,and the second highest value was before the noon. The first lowest value appeared in early morning,while the second lowest value appeared after the noon. Annual change was single-peak single-valley type. The maximum appeared in winter,while the minimum appeared in summer. [Conclusion]When forecasting thunderstorm,in the area with higher aerosol content,alarm threshold of electric field should be adjusted via comparison with actual observation,which had very strong regional characteristics. By analyzing real-time monitoring data of atmospheric electric field,thunderstorm forecast could be realized,and timeliness and accuracy of warning and forecast could be increased.展开更多
In order to study the variation of machine tools’dynamic characteristics in the manufacturing space,a Kriging approximate model is proposed.Finite element method(FEM)is employed on the platform of ANSYS to establish ...In order to study the variation of machine tools’dynamic characteristics in the manufacturing space,a Kriging approximate model is proposed.Finite element method(FEM)is employed on the platform of ANSYS to establish finite element(FE)model with the dynamic characteristic of combined interface for a milling machine,which is newly designed for producing aero engine blades by a certain enterprise group in China.The stiffness and damping of combined interfaces are adjusted by using adaptive simulated annealing algorithm with the optimizing software of iSIGHT in the process of FE model update according to experimental modal analysis(EMA)results.The Kriging approximate model is established according to the finite element analysis results utilizing orthogonal design samples by taking into account of the range of configuration parameters.On the basis of the Kriging approximate model,the response surfaces between key response parameter and configuration parameters are obtained.The results indicate that configuration parameters have great effects on dynamic characteristics of machine tools,and the Kriging approximate model is an effective and rapid method for estimating dynamic characteristics of machine tools in the manufacturing space.展开更多
文摘Meta-lens are a new type of planar optical element that can flexibly manipulate the phase, polarization and amplitude of the beam, and are currently receiving a great deal of attention as they are easier to process and manufacture. Off-axis meta-lens are a special type of meta-lens with a certain degree of dispersion that can be used as a beam-splitting element, providing a unique and feasible way to realize micro-miniature instruments. We analyze the effects of different numerical apertures and off-axis angles on the spectral resolution, focusing efficiency and simulation results of off-axis meta-lens to provide ideas for subsequent research and application of off-axis meta-lens. A number of off-axis meta-lens with parameters NA = 0.408 α = 13°, NA = 0.18 α = 13°<sup></sup> and NA = 0.408 α = 20° were simulated through Lumerical software. The results show that the off-axis angle is related to the resolution;the larger the angle, the better the spectral resolution but the lower the focusing efficiency;when the numerical aperture is smaller, the smaller the coverage of the phase distribution, which will lead to a larger deviation between simulation and theory. The designer needs to balance the numerical aperture, off-axis angle and other parameters reasonably according to the requirements in order to achieve the desired effect. The findings of this study have important reference values for the theoretical analysis of off-axis meta-lens and the design of parameters in practical applications. .
基金Mechanisms for important climatic catastrophes in China and theoretic study of the predic-tion" a project first set off in the "Plan for developing key national fundamental research" Project 97D033Q of Application Fund by the Science and Technology F
文摘The teleconnection distribution characteristics of sea surface temperature (SST) over the India Ocean and the precipitation during rainy season in China were studied by using the methods of EOF and CCA. The results indicate that the change of SST field will affect the change of rain belt during rainy seasons in China, and greatly affect the precipitation in northwest and southwest China, the Yangzi and Yellow River downstream basins. Strong signal phenomena of SSTA over India Ocean were revealed that showed the anoma-lous distribution of drought and flood in China. It shows that the precipitation during rainy seasons in China may be forecast by analyzing SST distribution characteristics over the India Ocean.
文摘In general, the location of traffic accidents is described as an address with text, so they are difficult to display on the map. The paper discusses how to utilize the geocoding technology and VRS-GPS positioning technology to record the traffic accidents with Geo-spatial information. Based on the spatial relationship between traffic accidents and road network elements, two-way association relationship is defined by spatial relationship computation. Then the paper presents the method which takes the potential of reducing accidents as an index to extract the black spots. Finally, in the discussion, the association relationship between black spots and traffic attributes is used to analyze the factors that resulting in traffic accidents.
基金Supported by the NSFC-Shandong Joint Fund “Study on the DisasterCausing Mechanism and Disaster Prevention Countermeasures of MultiSource Storm Surges”(No.U1706226)the National Natural Science Foundation of China “Coastal Engineering and Risk Assessment Based on a Four-Layer Nested Multi-Objective Probability Model”(No.51379195)+1 种基金the Natural Science Foundation of Shandong Province “Three-Layer Nested Multi-Objective Probability Prediction and Risk Assessment in Coastal Engineering”(No.ZR2013EEM034)the Program of Promotion Plan for Postgraduates’ Educational Quality “Paying More Attention to the Study on the Cultivation Mode of Mathematical Modeling for Engineering Postgraduates”(No.861801232417)
文摘When exploring the temporal and spatial change law of ocean environment, the most common method used is using smaller-scale observed data to derive the change law for a larger-scale system. For instance, using 30-year observation data to derive 100-year return period design wave height. Therefore, the study of inherent self-similarity in ocean hydrological elements becomes increasingly important to the study of multi-year return period design wave height derivation. In this paper, we introduced multifractal to analyze the statistical characteristics of wave height series data observed from oceanic hydrological station. An improvement is made to address the existing problems of the multifractal detrended fluctuation analysis (MF-DFA) method, where trend function showed a discontinuity between intervals. The improved MFDFA method is based on signal mode decomposition, replacing piecewise polynomial fitting used in the original method. We applied the proposed method to the wave height data collected at Chaolian Island, Shandong, China, from 1963 to 1989 and was able to conclude the wave height sequence presented weak multi-fractality. This result provided strong support to the past research on the derivation of multi-year return period design wave height with observed data. Moreover, the new method proposed in this paper also provides a new perspective to explore the intrinsic characteristic of data.
文摘The characteristic study of powder quartz is the basis of the comprehensive utilization of quartz powder resources.In this paper,the characteristic of a powder quartz mine in Yunnan Province is analyzed, through the analysis of X-ray diffraction,chemical composition,SEM analysis of the different samples those purified to different extent,etc.The results indicated that the powder quartz’s whiteness is 81.4, and the main mineral compositions are quartz,clay mineral(mostly kaolinite and illite) and a little of feldspar,and the content of quartz is about 85%。
文摘The results of characteristic comparison and principal component analysis showed that the major .characteristics of sesame varieties in Henan province were improved in the past decades. The sesame breeding works in the province were focused on the collection and the screening of the native germplasms from 1950 to 1969 and the mean values of the variety characteristics were the lowest. In 1970s,the pedigree breeding was mainly conducted,which resulted in the release of varieties of various types with better traits. During 1980s,the hybridization breeding was carried out dominantly with the varieties possessing fine traits. Since 1990,there were no better varieties released. To make new progresses,it is essential to renew the breeding method and at the same time to introduce and create special germplasms to widen the genetic background.
基金sponsored by the National Key Research and Development Program of China (Grant No. 2018YFC0704400)the Programmer of Introducing Talents (Grant No. B13011)
文摘The Asia Pacific Economic Cooperation(APEC)comprises of the world’s largest producers and consumers of energy,accounting for 60.3%of primary energy supply,50.0%of final energy consumption,and 63.0%of electricity generation worldwide in 2016.This study discusses the primary energy supply and final energy consumption situation of the APEC and analyzes the characteristics of electricity in terms of its generation structure based on fuel,consumption by the end-use sector,access to electricity,and so on.The renewable energy and electricity generation projections up to 2030 based on trends in the APEC are also assessed.It is seen that electricity in final energy consumption has been on an upward trend,with an average annual growth rate of about 4.8%during 2006–2016,in 2016,its share reached 24.3%.The industry sector consumes the largest share of electricity,accounting for about 45.5%in 2016.Coal supply and consumption peaked in 2011 and then began to decline,while renewable energy has been on an upward trend,with its primary energy supply share increasing from 4.80%in 2010 to 6.29%in 2016.Solar photovoltaic and onshore wind power are on the verge of costing less than the operating cost of existing coal-fired plants in 2018.In the APEC’s target scenario in which renewable energy is doubled,the predicted net growth from 2017 to 2030 of solar,wind,and hydro power is about 963,497,and 157 GW,respectively,and to reach this target,the APEC economies need to accelerate renewable energy development.
基金Project(50878133) supported by the National Natural Science Foundation of ChinaProject (2007R37) supported by Excellent Talents in Liaoning Province+1 种基金Project (2008S193) supported by the Key Laboratory Fund of Education Department in Liaoning ProvinceProject(1071211-1-00) supported by the Scientific and Technical Fund Project Subsidy of Shenyang Province
文摘Based on the phase change material (PCM) thermal characteristic,some testing methods such as differential scanning calorimeter (DSC) etc were used to select the low melting mixture of capric and lauric acid as PCM of phase change wallboard (PCW). The PCW room was established,and some contrast analysis of the storage and exchange thermal characteristic of PCW room and ordinary wall room were made under different conditions. The results show that the fluctuation of indoor air temperature in PCW room is smaller than that in ordinary room obviously. The exchange energy of PCM room with outdoor is less than that of ordinary wall room. In the winter condition,PCW room utilizes valley period electricity to storage energy in the night,while releases at peak period electricity in daytime,which can divert 40% of peak load. In the summer condition,PCW room can reduce the peak cooling load by 25% compared with ordinary wall room.
文摘Characteristic analysis of transient electromagnetic disturbance data is very important. In this paper, the time-domain and frequency-domain characteristics of transient electromagnetic disturbance caused by switching operations in substations are analyzed. Two methods are adopted in time-domain analysis. One method is histogram and the other one is normality test. An appropriate procedure for the normality test is proposed. Furthermore, the method used in frequency- domain analysis is to obtain overall envelope. These statistical characteristic analysis methods are showed to be of great value in analyses of the measured samples. The simulation results showed that these methods are effective.
基金Supported by the National Native Science Foundation of China
文摘This paper analyses the transient characteristics of high temperature CMOS inverters and gate circuits, and gives the computational formulas of their rise time, fall time and delay time. It may be concluded that the transient characteristics of CMOS inverters and gate circuits deteriorate due to the reduction of carrier mobilities and threshold voltages of MOS transistors and the increase of leakage currents of MOS transistors drain terminal pn junctions. The calculation results can explain the experimental phenomenon.
文摘Objective(s): Laryngeal inflammations lead to voice disorders. Medical conditions such as chronic laryngitis, gastroesophageal reflux, laryngopharyngeal reflux, Reinke edema and/or vocal folds hemorrhage, result in diverse symptoms including chronic cough, throat cleaning and dysphonia (e.g. hoarseness). In turn, the dysphonic symptoms can be evaluated via subjective and objective procedures. The objective procedures usually include self-perceived questionnaires like the Voice Handicap Index (VHI). Studies reported that VHI can distinguish objectively dysphonic and non-dysphonic populations using the cut-off points of Receiver Operating Characteristic Curves. The purpose of this study was to calculate the cut-off points for individuals exhibiting voice symptoms which had been developed from laryngeal inflammatory diseases in Greece. Methods: One hundred and twelve participants (90 non-dysphonic and 22 dysphonic) filled in the Hellenic Voice Handicap Index (VHI) and the Greek translated version of Voice Evaluation Template (VEF) were administrated. All subjects were evaluated by an Otolaryngologist and a Speech-Language Pathologist. Results: The group with voice disorders exhibited higher VHI scores (in total and in its 3 subdomains) compared to non-dysphonic subgroup. Statistical significant differences were found for all VHI’s total cut-off point of 19.50 (sensitivity: 0.882, 1-specificity: 0.011) and for its three subdomains [functional 6.50 (sensitivity = 0.636, and 1-specificity = 0.022);physical 9.50 (sensitivity = 0.636, and 1-specificity = 0.000);emotional 6.50 (sensitivity = 0.455, and 1-specificity = 0.133)]. Conclusion: The preliminary results showed that VHI could discriminate individuals having voice disorders from laryngeal inflammations. The Voice Handicap Index can be used as a primary health care tool and a self-monitoring procedure in acute and sub-acute phases of the laryngeal inflammation.
文摘Electric vehicle, as a clean energy industry, is an important branch. Electric vehicles not only are the energy of the electric user, but also can be used as mobile and distributed energy storage unit to the grid. As a precondition of safety operation for power grid, studies of EVs’ charging load characteristics is also the theoretical basis of intelligent scheduling EVs charging orderly. This paper assesses the future of the electric vehicles development prospects, and secondly establishes a charging model of a single EV. Then, considering stochastic distribution of the initial state-of-charge (SOC0) and the arriving time of the vehicles, a cluster model of the charging station is proposed. Meanwhile, the paper from the types and charging mode of electric vehicles analyzes the behavior of EV. Finally, an example simulation is validated.
文摘Dynamic capacity increase in high voltage electric power transmission line is currently the most economical method for solving electric power transmission bottleneck nowadays. DS18B20 temperature sensor is applied to the dynamic capacity increase of high voltage transmission lines to measure the conductor temperature and ambient temperature. The paper is focused on the experiment of DS18B20 both in the laboratory and outside. From the result of the lab temperature measurement data analysis, using 4 DS18B20’s is the most suitable plan, considering both accuracy and economical efficiency. In the experiment outside, we get four groups of conductor (uncharged) temperature and four groups of ambient temperature. The data proved that DS18B20 has good stability, and small measurement error. It is suitable for measuring the temperature of conductor and ambient in dynamic capacity increase, and helpful to improve the accuracy of the calculation of capacity increasing.
文摘This paper looks at the development of a class of Exponential Compact Higher Order (ECHO) schemes and attempts to comprehend their behaviour by introducing different combinations of discrete source function and its derivatives. The characteristic analysis is performed for one-dimensional schemes to understand the efficiency of the scheme and a similar analysis has been introduced for higher dimensional schemes. Finally, the developed schemes are used to solve several example problems and compared the error norms and rates of convergence.
基金Supported by Huaiyin Institute of Technology Young Talent Project of Science Foundation(HGQN0707)
文摘This thesis gives overview of the connotation of rural spatial structure,indicating 4 kinds of elements,namely nodus,passage,region and flow.Their spatial arrangement and interaction lead to the corresponding rural spatial structure.This thesis also offers panorama of the related theoretical progress of intra-county and rural areas,indicating that the research theories of regional spatial structure at present,mainly focus on macroscopic region or urban space,but there is shortage of researches on county spatial structure,especially microscopic rural spatial structure.On such basis,4 kinds of theoretical models and characteristics of regional spatial structure have been introduced.We build analysis index system of rural structural elements on the basis of 4 elements,and conduct rural spatial structural analysis,taking Jinhu County as an example.The result shows that rural spatial structure in Jinhu County is still at stage of nucleus-cluster development and rural system is not so sound.In addition,the passage network system of infrastructure has not taken shape,and county economy presents diseconomy of scale.The spatial interaction and association among towns in Jinhu County are weak.The characteristic analysis model of spatial structure in this research can objectively reflect regional characteristic of spatial structure.
文摘In this paper, the mathematical model of solenoid valve in the fuel injection system of gas engine is built. Simulation software Matlab/Simulink are employed to analyze the impact which the voltage, number of the coil turns and air gap width may produce to the open and close characteristics of the solenoid valve. The ideal response characteristics are got through the calculation. An optimal scheme which satisfies the operation requirements is put forward. The driving voltage and maintaining voltage are set as 90 V and 21 V;number of the coil turns is 30 N;air gap is determined as 0.6 mm;the opening and closing time are respectively 0.98 ms and 0.8 ms. This paper can be used as a reference for the design of the solenoid valve.
基金supported by the National Natural Science Foundation of China(Nos.12072253,11972176,and 12062011)the Doctoral Science Fund of Lanzhou University of Technology of China(No.062002)the Opening Project from the State Key Laboratory for Strength and Vibration of Mechanical Structures of China(No.SV2021-KF-19)。
文摘In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further improve its working performance,a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect.Next,by using the current theoretical model,some numerical analyses and discussion about the surface effect,the corresponding critical thickness of the nanoplate,and the distributions of the physical fields(including the electron concentration perturbation,the electric potential,the electric field,the average electric displacement,the effective polarization charge density,and the total charge density)under different initial state electron concentrations,as well as their active manipulation via some external magnetic field,pre-stress,and temperature stimuli,are performed.Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment,this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect,but also assists the design of a series of multiferroic PS nanodevices.
文摘The electrostatic discharge(ESD)phenomenon is very common,in daily life,many places will appear ESD phenomenon.However,ESD is a potential hazard for integrated circuits.This paper analyzes the ESD protection design and characteristics of advanced process integrated circuits,and puts forward personal views combined with experience,hoping to bring help to the people who pay attention to the ESD protection of integrated circuits.
文摘[Objective]The research aimed to analyze characteristics of atmospheric electric field in polluted area. [Method] By using data of atmospheric electric field meter in Taiyuan in 2009,daily and annual changes of atmospheric electric field in Taiyuan were analyzed. [Result]Atmospheric electric field intensity in Taiyuan was higher than that in other areas. Daily change was double-peak double-valley type. The first highest value appeared at nightfall,and the second highest value was before the noon. The first lowest value appeared in early morning,while the second lowest value appeared after the noon. Annual change was single-peak single-valley type. The maximum appeared in winter,while the minimum appeared in summer. [Conclusion]When forecasting thunderstorm,in the area with higher aerosol content,alarm threshold of electric field should be adjusted via comparison with actual observation,which had very strong regional characteristics. By analyzing real-time monitoring data of atmospheric electric field,thunderstorm forecast could be realized,and timeliness and accuracy of warning and forecast could be increased.
基金Project(2009ZX04001-073)supported by the Important National Science&Technology Specific Projects of ChinaProject(51105025)supported by the National Natural Science Foundation of China
文摘In order to study the variation of machine tools’dynamic characteristics in the manufacturing space,a Kriging approximate model is proposed.Finite element method(FEM)is employed on the platform of ANSYS to establish finite element(FE)model with the dynamic characteristic of combined interface for a milling machine,which is newly designed for producing aero engine blades by a certain enterprise group in China.The stiffness and damping of combined interfaces are adjusted by using adaptive simulated annealing algorithm with the optimizing software of iSIGHT in the process of FE model update according to experimental modal analysis(EMA)results.The Kriging approximate model is established according to the finite element analysis results utilizing orthogonal design samples by taking into account of the range of configuration parameters.On the basis of the Kriging approximate model,the response surfaces between key response parameter and configuration parameters are obtained.The results indicate that configuration parameters have great effects on dynamic characteristics of machine tools,and the Kriging approximate model is an effective and rapid method for estimating dynamic characteristics of machine tools in the manufacturing space.
