Local dimming(局部调光)是一种低成本提升车载显示器对比度和清晰度的技术。在目前OLED技术尚无法突破严苛的汽车环境要求的状况下,局部调光是一种首选的成本和性能兼顾的技术。在满足汽车环境要求的同时,大幅提升了显示器的清晰度,提...Local dimming(局部调光)是一种低成本提升车载显示器对比度和清晰度的技术。在目前OLED技术尚无法突破严苛的汽车环境要求的状况下,局部调光是一种首选的成本和性能兼顾的技术。在满足汽车环境要求的同时,大幅提升了显示器的清晰度,提高了显示内容的辨识度,同时成本的上升也在合理范围内。它能给客户带来更好的体验,使驾驶更为安全。本文对它的工作原理以及如何应用进行了阐述,给读者提供了一种思路和方法来提升车载显示器的对比度。展开更多
Blast furnace(BF)burden surface contains the most abundant,intuitive and credible smelting information and acquiring high-definition and high-brightness optical images of which is essential to realize precise material...Blast furnace(BF)burden surface contains the most abundant,intuitive and credible smelting information and acquiring high-definition and high-brightness optical images of which is essential to realize precise material charging control,optimize gas flow distribution and improve ironmaking efficiency.It has been challengeable to obtain high-quality optical burden surface images under high-temperature,high-dust,and extremelydim(less than 0.001 Lux)environment.Based on a novel endoscopic sensing detection idea,a reverse telephoto structure starlight imaging system with large field of view and large aperture is designed.Combined with a water-air dual cooling intelligent self-maintenance protection device and the imaging system,a starlight high-temperature industrial endoscope is developed to obtain clear optical burden surface images stably under the harsh environment.Based on an endoscope imaging area model,a material flow trajectory model and a gas-dust coupling distribution model,an optimal installation position and posture configuration method for the endoscope is proposed,which maximizes the effective imaging area and ensures large-area,safe and stable imaging of the device in a confined space.Industrial experiments and applications indicate that the proposed method obtains clear and reliable large-area optical burden surface images and reveals new BF conditions,providing key data support for green iron smelting.展开更多
Local dimming(区域背光调控)是改善被动发光的液晶显示器性能的重要技术。采用一套自主开发的仿真算法,在充分验证其准确性后,对液晶显示器的对比度和光晕指数随分区数的变化关系进行了计算仿真与分析,最终形成背光分区数设计指引。分...Local dimming(区域背光调控)是改善被动发光的液晶显示器性能的重要技术。采用一套自主开发的仿真算法,在充分验证其准确性后,对液晶显示器的对比度和光晕指数随分区数的变化关系进行了计算仿真与分析,最终形成背光分区数设计指引。分析结果表明:对比度随分区数的增加而增加,RTINGS棋盘格图片最大价值点(导数为1的点)为300分区,要达到足够接近最大对比度,则需要1600分区左右;背光行列分区数为8的倍数时有更好的对比度体现;光晕指数与对比度随分区数变化的趋势相似,RTINGS十字架图片最大价值点(导数为1)为500分区。展开更多
Dimmers are very widely applied in theatres,cinemas,dancing-parties, auditoriums and signal systems.They are usually supplied by single-stage AC/AC converters in the past with voltage regulation technique with the dis...Dimmers are very widely applied in theatres,cinemas,dancing-parties, auditoriums and signal systems.They are usually supplied by single-stage AC/AC converters in the past with voltage regulation technique with the disadvantages of high total harmonic distortion,low power factor and poor power transfer efficiency.This paper introduces a novel method-DC-modulation that implements DC/DC conversion technology into AC/AC converters.The DC-modulated single-stage PFC AC/AC converters effectively improved the power factor up to 0.999 and the power transfer efficiency up to 97.8 %.The experimental results verified our design and calculation.This technique will be widely used in light dimming and other industrial applications.展开更多
In recent years, fluorescent lamp dimming controls are an integral part of daylight artificial light integrated schemes intended for realization of energy savings. However, dimming, like any lighting option, presents ...In recent years, fluorescent lamp dimming controls are an integral part of daylight artificial light integrated schemes intended for realization of energy savings. However, dimming, like any lighting option, presents its own particular challenges and potential tradeoffs. In view of this, the present manuscript depicts the preliminary work progress carried out to arrive at a comprehensive idea on dimming implications on key factors: electrical characteristics, photometric distributions of lighting systems and influence on quality as well as quantity of visual environment. The objective is to experimentally establish the acceptable range of dimming control voltage that would satisfy both electrical and photometric performance of luminaire. The vital part of the paper is devoted towards presentation of measurement results. For the experimental analysis, three representative samples of different commercial analog 1-10VDC electronic dimmable ballasts and fluorescent fixtures are compared and evaluated over their control voltage dimming range.展开更多
Aiming at the needs of different lighting applications, combined with the characteristics of LED dimming and color control, and using MSP430 digital control technology, a novel LED intelligent dimming and color contro...Aiming at the needs of different lighting applications, combined with the characteristics of LED dimming and color control, and using MSP430 digital control technology, a novel LED intelligent dimming and color control system was designed. The system integrated Bluetooth remote, human infrared sensor, voice/gesture control and other control modes, which could achieve LED multi-mode dimming and color intelligent control. System hardware and software were designed to develop a prototype to experimental verification. The designed method proposes new ideas and information for LED control.展开更多
Marine Cloud Brightening (MCB), should it ever need to be deployed, envisions the formation of 1017salt Cloud Condensation Nuclei (CCN) per second coming from each of several thousand vessels deployed worldwide. The c...Marine Cloud Brightening (MCB), should it ever need to be deployed, envisions the formation of 1017salt Cloud Condensation Nuclei (CCN) per second coming from each of several thousand vessels deployed worldwide. The creation of this many nuclei on such a vast scale, from micron- or submicron-sized seawater droplets, preferably mono-disperse, poses a considerable engineering challenge. Various existing or experimental spray methods were investigated for feasibility, resulting in the identification of a few with promising results. Electro-spraying from Taylor cone-jets, using either silicon micromachined long capillaries or short capillary polymer substrates attached to a porous substrate, appears to have the best potential for implementation of all the methods that have been investigated so far.展开更多
Marine Cloud Brightening (MCB) by effervescent spray atomization of mixed sea water brine with air is a candidate for solar radiation management to compensate for global warming. We discovered that the flow from mixin...Marine Cloud Brightening (MCB) by effervescent spray atomization of mixed sea water brine with air is a candidate for solar radiation management to compensate for global warming. We discovered that the flow from mixing tee nozzle described earlier had occasional unstable slug flow. A new design that adding rotational swirl to the salt brine as it is mixed into the air stabilized the nozzle flow and no longer showed slug flow in spray pictures. Flow equations were developed for the relatively low speed of sound of a choked flow mixed brine and air nozzle. Experimental mixed flow measurements with 300b pressure and a 200 μm diameter nozzle and calculations using perfect gas, and isotropic processes equations compared well with the chocked flow equations. Analysis in EXCEL of particle sizers measurements from both a scanning mobility particle sizer (SMPS) and an aerodynamic particle sizer (APS) showed production of many nanometer sized particles estimated as usable for MCB. A small number of micron sized particles were also always present but with about 90% of the sprayed mass. This is a first report with good data over the complete size range. The micron sized particles measured were similar to the measurements of earlier reports which reported no nanometer sized particles. We hypothesize that many nano-particles are always produced by liquid-air effervescent sprays, but earlier, were not observed because SMPS instruments were not available. The presence of the large mass percentage of large particles in the spray may cause problems by evaporative cooling preventing the rise of the MCB particles. We suggest future systems design with an impactor filter to remove the large particles. Calculations combining increased brine concentration, lower pressure, and larger nozzle area showed that significant reductions in required power and number of nozzles could be realized. An EXCEL model is developed to calculate flow from experimental analysis equations and compare with mixed choked flow equations. Solving with the model predicted the power required and the number of nozzles required to produce 10<sup>15</sup> particles/s. The model showed that increasing brine concentration strongly lowered total power. Lowering pressure decreased power and increased number of nozzles. Increasing nozzle area lowered the number of nozzles. This model predicted that, at 300b pressure and 200μm diameter nozzle as the experiment but using an increased brine concentration of 0.1 instead of 0.032 would require only 115 nozzles instead of 358 and power of 146 kw instead of 493 kw. Combining increased brine concentration, lower pressure, and larger nozzle area, the model predicted that with a 1 mm diameter nozzle at 30b pressure and salt concentration of 0.2, the nozzle count and power required would drop to only 24 nozzles and power of 28 kw. Whether extending the model to these conditions is valid is not known but suggests further development should be investigated. Filtering out and reusing the 90% or greater large particles mass sprayed combined with the lower power advantage of higher brine concentration is suggested for future systems.展开更多
We investigate the spatial extent of a statistically highly significant shift in atmospheric temperatures over Europe around 1987-1988 using a boot-strap change point algorithm. According to this algorithm, this chang...We investigate the spatial extent of a statistically highly significant shift in atmospheric temperatures over Europe around 1987-1988 using a boot-strap change point algorithm. According to this algorithm, this change point (average warming of about one degree Celsius) is statistically highly significant (p > 99.9999%). The change point is consistently present in satellite and surface temperature measurements as well as temperature re-analyses and ocean heat content over most of Western Europe. We also find a connection with parts of the North Atlantic Ocean and eastern Asia. Although the time of change coincides with the North Atlantic Oscillation (NAO) going from negative to positive, the consistent warmer temperatures throughout the decades after 1987-1988 does not coincide with a persistent shift of the NAO, as it returns to a neutral/negative in the 1990’s. Furthermore, the shift does not coincide with any other known mode of multidecadal internal climate variability. We argue that the notion of a shift is “spurious”, i.e. the result of a fast change in Europe from dimming to brightening combined with an accidental sequence of cold (negative NAO) and warm (positive) NAO years during this period. The “shift” could therefore be considered as a fingerprint of European brightening during the last few decades.展开更多
This paper presents an off-line integrated full ballast to supply a 35W assembly of Power LEDs. The proposed solution integrates an input PFC stage (a flyback converter operating in DCM) and a DC-DC output converter (...This paper presents an off-line integrated full ballast to supply a 35W assembly of Power LEDs. The proposed solution integrates an input PFC stage (a flyback converter operating in DCM) and a DC-DC output converter (a buck converter) into a single switch power stage, operating with peak current control. As it will be shown, this control scheme maintains the current through the load constant, regardless of the instantaneous value of the DC link voltage. This issue allows the use of a small capacitor for the DC link, which enhances the overall system reliability. The complete ballast has full dimming capability, and all the analysis and design steps are presented, thus ensuring the fulfilling of the existing regulations. The novelty of the final solution comes from the simplicity and robustness of the control scheme in an integrated compact single-switch power stage. A final prototype of the ballast has been built and tested, and experimental results are shown in the last part of the paper. Finally, conclusions and future developments are shown.展开更多
The 16 August 1999 EUV brightenings are numerically simulated by a third-order upwind compact scheme,basing on the TRACE observation.The present simulation can give a possible explanation to its formation and evolutio...The 16 August 1999 EUV brightenings are numerically simulated by a third-order upwind compact scheme,basing on the TRACE observation.The present simulation can give a possible explanation to its formation and evolution.The numerical results show that the initial reconnection jets at around X-point are responsible for the occurrence of EUV brightening.The strong and superposed ejections caused by the first and second coalescence of magnetic islands are possibly related to the lifted material which initially appeared as absorption features and Later EUV-emitting structures respectively.The bi-directional reconnection jets may correspond to the lifted material that either continued to move upward along the apparently open field lines or fell down to the surface.展开更多
In integrated factories of pulp and paper, the bleaching control is made by kappa number and/or brightness. However, the product paper is evaluated and valued for its whiteness. The level of final brightness of pulp c...In integrated factories of pulp and paper, the bleaching control is made by kappa number and/or brightness. However, the product paper is evaluated and valued for its whiteness. The level of final brightness of pulp certainly affects the demand for optical brighteners in paper manufacturing, nevertheless, there is not a direct correlation between consumption of optical brightener and final brightness, being the method of bleaching pulp, especially from the final stage of bleaching, also important in relation to this demand. Therefore, this study aimed to evaluate the potential of using the parameter whiteness as a tool to control bleaching pulp, instead of the traditional brightness and evaluate the impacts of different methods of bleaching and the pulp final brightness level in action of optical brighteners, to improve their performance. It was observed that the whiteness and brightness of the pulp are highly correlated and that the control of the bleaching plant can be done by any one of these two parameters. It was also concluded that, considering current prices of bleaching reagents and of optical brighteners, it is better to bleach the pulp up to lower brightness values (e.g. 88% ISO) and use larger amounts of optical brighteners to brighten the mass until the whiteness of 130 CIE. This conclusion is valid for whiteness measured before the size press. Further studies are needed to validate this conclusion considering the finished product.展开更多
基金the National Natural Science Foundation of China(62273359)the General Project of Hunan Natural Science Foundation of China(2022JJ30748)the National Major Scientific Research Equipment of China(61927803)。
文摘Blast furnace(BF)burden surface contains the most abundant,intuitive and credible smelting information and acquiring high-definition and high-brightness optical images of which is essential to realize precise material charging control,optimize gas flow distribution and improve ironmaking efficiency.It has been challengeable to obtain high-quality optical burden surface images under high-temperature,high-dust,and extremelydim(less than 0.001 Lux)environment.Based on a novel endoscopic sensing detection idea,a reverse telephoto structure starlight imaging system with large field of view and large aperture is designed.Combined with a water-air dual cooling intelligent self-maintenance protection device and the imaging system,a starlight high-temperature industrial endoscope is developed to obtain clear optical burden surface images stably under the harsh environment.Based on an endoscope imaging area model,a material flow trajectory model and a gas-dust coupling distribution model,an optimal installation position and posture configuration method for the endoscope is proposed,which maximizes the effective imaging area and ensures large-area,safe and stable imaging of the device in a confined space.Industrial experiments and applications indicate that the proposed method obtains clear and reliable large-area optical burden surface images and reveals new BF conditions,providing key data support for green iron smelting.
文摘Dimmers are very widely applied in theatres,cinemas,dancing-parties, auditoriums and signal systems.They are usually supplied by single-stage AC/AC converters in the past with voltage regulation technique with the disadvantages of high total harmonic distortion,low power factor and poor power transfer efficiency.This paper introduces a novel method-DC-modulation that implements DC/DC conversion technology into AC/AC converters.The DC-modulated single-stage PFC AC/AC converters effectively improved the power factor up to 0.999 and the power transfer efficiency up to 97.8 %.The experimental results verified our design and calculation.This technique will be widely used in light dimming and other industrial applications.
文摘In recent years, fluorescent lamp dimming controls are an integral part of daylight artificial light integrated schemes intended for realization of energy savings. However, dimming, like any lighting option, presents its own particular challenges and potential tradeoffs. In view of this, the present manuscript depicts the preliminary work progress carried out to arrive at a comprehensive idea on dimming implications on key factors: electrical characteristics, photometric distributions of lighting systems and influence on quality as well as quantity of visual environment. The objective is to experimentally establish the acceptable range of dimming control voltage that would satisfy both electrical and photometric performance of luminaire. The vital part of the paper is devoted towards presentation of measurement results. For the experimental analysis, three representative samples of different commercial analog 1-10VDC electronic dimmable ballasts and fluorescent fixtures are compared and evaluated over their control voltage dimming range.
文摘Aiming at the needs of different lighting applications, combined with the characteristics of LED dimming and color control, and using MSP430 digital control technology, a novel LED intelligent dimming and color control system was designed. The system integrated Bluetooth remote, human infrared sensor, voice/gesture control and other control modes, which could achieve LED multi-mode dimming and color intelligent control. System hardware and software were designed to develop a prototype to experimental verification. The designed method proposes new ideas and information for LED control.
文摘Marine Cloud Brightening (MCB), should it ever need to be deployed, envisions the formation of 1017salt Cloud Condensation Nuclei (CCN) per second coming from each of several thousand vessels deployed worldwide. The creation of this many nuclei on such a vast scale, from micron- or submicron-sized seawater droplets, preferably mono-disperse, poses a considerable engineering challenge. Various existing or experimental spray methods were investigated for feasibility, resulting in the identification of a few with promising results. Electro-spraying from Taylor cone-jets, using either silicon micromachined long capillaries or short capillary polymer substrates attached to a porous substrate, appears to have the best potential for implementation of all the methods that have been investigated so far.
文摘Marine Cloud Brightening (MCB) by effervescent spray atomization of mixed sea water brine with air is a candidate for solar radiation management to compensate for global warming. We discovered that the flow from mixing tee nozzle described earlier had occasional unstable slug flow. A new design that adding rotational swirl to the salt brine as it is mixed into the air stabilized the nozzle flow and no longer showed slug flow in spray pictures. Flow equations were developed for the relatively low speed of sound of a choked flow mixed brine and air nozzle. Experimental mixed flow measurements with 300b pressure and a 200 μm diameter nozzle and calculations using perfect gas, and isotropic processes equations compared well with the chocked flow equations. Analysis in EXCEL of particle sizers measurements from both a scanning mobility particle sizer (SMPS) and an aerodynamic particle sizer (APS) showed production of many nanometer sized particles estimated as usable for MCB. A small number of micron sized particles were also always present but with about 90% of the sprayed mass. This is a first report with good data over the complete size range. The micron sized particles measured were similar to the measurements of earlier reports which reported no nanometer sized particles. We hypothesize that many nano-particles are always produced by liquid-air effervescent sprays, but earlier, were not observed because SMPS instruments were not available. The presence of the large mass percentage of large particles in the spray may cause problems by evaporative cooling preventing the rise of the MCB particles. We suggest future systems design with an impactor filter to remove the large particles. Calculations combining increased brine concentration, lower pressure, and larger nozzle area showed that significant reductions in required power and number of nozzles could be realized. An EXCEL model is developed to calculate flow from experimental analysis equations and compare with mixed choked flow equations. Solving with the model predicted the power required and the number of nozzles required to produce 10<sup>15</sup> particles/s. The model showed that increasing brine concentration strongly lowered total power. Lowering pressure decreased power and increased number of nozzles. Increasing nozzle area lowered the number of nozzles. This model predicted that, at 300b pressure and 200μm diameter nozzle as the experiment but using an increased brine concentration of 0.1 instead of 0.032 would require only 115 nozzles instead of 358 and power of 146 kw instead of 493 kw. Combining increased brine concentration, lower pressure, and larger nozzle area, the model predicted that with a 1 mm diameter nozzle at 30b pressure and salt concentration of 0.2, the nozzle count and power required would drop to only 24 nozzles and power of 28 kw. Whether extending the model to these conditions is valid is not known but suggests further development should be investigated. Filtering out and reusing the 90% or greater large particles mass sprayed combined with the lower power advantage of higher brine concentration is suggested for future systems.
文摘We investigate the spatial extent of a statistically highly significant shift in atmospheric temperatures over Europe around 1987-1988 using a boot-strap change point algorithm. According to this algorithm, this change point (average warming of about one degree Celsius) is statistically highly significant (p > 99.9999%). The change point is consistently present in satellite and surface temperature measurements as well as temperature re-analyses and ocean heat content over most of Western Europe. We also find a connection with parts of the North Atlantic Ocean and eastern Asia. Although the time of change coincides with the North Atlantic Oscillation (NAO) going from negative to positive, the consistent warmer temperatures throughout the decades after 1987-1988 does not coincide with a persistent shift of the NAO, as it returns to a neutral/negative in the 1990’s. Furthermore, the shift does not coincide with any other known mode of multidecadal internal climate variability. We argue that the notion of a shift is “spurious”, i.e. the result of a fast change in Europe from dimming to brightening combined with an accidental sequence of cold (negative NAO) and warm (positive) NAO years during this period. The “shift” could therefore be considered as a fingerprint of European brightening during the last few decades.
文摘This paper presents an off-line integrated full ballast to supply a 35W assembly of Power LEDs. The proposed solution integrates an input PFC stage (a flyback converter operating in DCM) and a DC-DC output converter (a buck converter) into a single switch power stage, operating with peak current control. As it will be shown, this control scheme maintains the current through the load constant, regardless of the instantaneous value of the DC link voltage. This issue allows the use of a small capacitor for the DC link, which enhances the overall system reliability. The complete ballast has full dimming capability, and all the analysis and design steps are presented, thus ensuring the fulfilling of the existing regulations. The novelty of the final solution comes from the simplicity and robustness of the control scheme in an integrated compact single-switch power stage. A final prototype of the ballast has been built and tested, and experimental results are shown in the last part of the paper. Finally, conclusions and future developments are shown.
基金Supported by the National Natural Science Foundation of China(40374056,40536029,40574068)the International Collaboration Research Team Program of Chinese Academy of Sciences
文摘The 16 August 1999 EUV brightenings are numerically simulated by a third-order upwind compact scheme,basing on the TRACE observation.The present simulation can give a possible explanation to its formation and evolution.The numerical results show that the initial reconnection jets at around X-point are responsible for the occurrence of EUV brightening.The strong and superposed ejections caused by the first and second coalescence of magnetic islands are possibly related to the lifted material which initially appeared as absorption features and Later EUV-emitting structures respectively.The bi-directional reconnection jets may correspond to the lifted material that either continued to move upward along the apparently open field lines or fell down to the surface.
基金Funding provided by the Minas Gerais State Research Foundation(FAPEMIG)from the Brazilian National Council for Science and Technology Development(CNPq)is greatly appreciated.
文摘In integrated factories of pulp and paper, the bleaching control is made by kappa number and/or brightness. However, the product paper is evaluated and valued for its whiteness. The level of final brightness of pulp certainly affects the demand for optical brighteners in paper manufacturing, nevertheless, there is not a direct correlation between consumption of optical brightener and final brightness, being the method of bleaching pulp, especially from the final stage of bleaching, also important in relation to this demand. Therefore, this study aimed to evaluate the potential of using the parameter whiteness as a tool to control bleaching pulp, instead of the traditional brightness and evaluate the impacts of different methods of bleaching and the pulp final brightness level in action of optical brighteners, to improve their performance. It was observed that the whiteness and brightness of the pulp are highly correlated and that the control of the bleaching plant can be done by any one of these two parameters. It was also concluded that, considering current prices of bleaching reagents and of optical brighteners, it is better to bleach the pulp up to lower brightness values (e.g. 88% ISO) and use larger amounts of optical brighteners to brighten the mass until the whiteness of 130 CIE. This conclusion is valid for whiteness measured before the size press. Further studies are needed to validate this conclusion considering the finished product.