Background:Irregular heartbeats can have serious health implications if left undetected and untreated for an extended period of time.Methods:This study leverages machine learning(ML)techniques to classify electrocardi...Background:Irregular heartbeats can have serious health implications if left undetected and untreated for an extended period of time.Methods:This study leverages machine learning(ML)techniques to classify electrocardiogram(ECG)heartbeats,comparing traditional feature-based ML methods with innovative image-based approaches.The dataset underwent rigorous preprocessing,including down-sampling,frequency filtering,beat segmentation,and normalization.Two methodologies were explored:(1)handcrafted feature extraction,utilizing metrics like heart rate variability and RR distances with LightGBM classifiers,and(2)image transformation of ECG signals using Gramian Angular Field(GAF),Markov Transition Field(MTF),and Recurrence Plot(RP),enabling multimodal input for convolutional neural networks(CNNs).The Synthetic Minority Oversampling Technique(SMOTE)addressed data imbalance,significantly improving minority-class metrics.Results:The handcrafted feature approach achieved notable performance,with LightGBM excelling in precision and recall.Image-based classification further enhanced outcomes,with a custom Inception-based CNN,attaining an 85%F1 score and 97%accuracy using combined GAF,MTF,and RP transformations.Statistical analyses confirmed the significance of these improvements.Conclusion:This work highlights the potential of ML for cardiac irregularities detection,demonstrating that combining advanced preprocessing,feature engineering,and state-of-the-art neural networks can improve classification accuracy.These findings contribute to advancing AI-driven diagnostic tools,offering promising implications for cardiovascular healthcare.展开更多
In the tropical regions represented by Hainan,there are abundant solar and thermal resources,and it is relatively suitable for the construction of photovoltaic greenhouse(PVG).However,the construction of PVG still rel...In the tropical regions represented by Hainan,there are abundant solar and thermal resources,and it is relatively suitable for the construction of photovoltaic greenhouse(PVG).However,the construction of PVG still relies mainly on experience and is incapable of quantifying the balance between the photovoltaic(PV)generation and the light requirements for agricultural production.As a result,actual PVGs are primarily PV-based,without carefully considering the needs of agricultural daylighting.To quantify the influence of the design parameters of PVGs and the layout of PV panels on the internal daylighting of serrated PVGs,and to optimize the daylighting design of the roof,this paper utilizes the Design Builder software to establish gradient models for a multi-span serrated-type PVG in tropical regions.Gradient models were established in terms of aspects,namely span,width of longitudinal/transverse daylighting strip,height,roof angle,and photovoltaic panel coverage rate(PCR).Daylighting in the greenhouse of each gradient model was simulated,and with the annual average daily light integral(A_(DLI))and distribution uniformity(DU)as evaluation indicators,the influence of various design parameters on the daylighting inside the greenhouse was quantified.The result reveals that:(1)PCR is the decisive indicator for daylighting in the PVG,and a function between PCR and the A_(DLI) is derived as A_(DLI)=-15.5 PCR+16.841;(2)Increasing the width of longitudinal daylighting strip significantly improves the A_(DLI) and enhances DU while increasing the span has a noticeable effect on improving A_(DLI) but does not significantly enhance DU;(3)Increasing the eave height without changing PCR does not enhance A_(DLI) but effectively improves DU;increasing the transverse daylighting strip and adjusting the roof angle hardly improves A_(DLI).In summary,it is recommended that the optimal span for PVGs in tropical regions be set within the range of 6.5-8.0m,and the eave height be set within the range of 2.5-3.5m.Preferably,the longitudinal daylighting strip with a width ranging from 0.5-0.8m should be installed.Based on the above relationship function,the PCR can be calculated according to the appropriate light demand for the cultivated crops.The daylighting design theory proposed in this paper can provide a theoretical basis and reference for the healthy development of the PV industry in tropical regions.展开更多
Supplemental lighting has emerged as a widely adopted technique in greenhouse cultivation to enhance product visibility andimprove theflavor characteristics ofChinese bayberry(Myrica rubra)in the internationalmarket.W...Supplemental lighting has emerged as a widely adopted technique in greenhouse cultivation to enhance product visibility andimprove theflavor characteristics ofChinese bayberry(Myrica rubra)in the internationalmarket.While studies on lighting have predominantly focused on colorimetry,limited research has addressed the precise control of chromatic parameters and their effect on fruit quality.This study examined the effects of varying lighting conditions,specifically correlated color temperatures and illuminance,on the growth and quality of Chinese bayberry varieties“Black Charcoal”and“Dongkui”using a precision control system.The bayberry plants were exposed to a constant illuminance of 155μmol·m^(-2)·s^(-1) with chromatic levels ranging from 2250 to 6000 K.Black Charcoal demonstrated substantial improvements under different chromatic parameters,with fruit weight and size increasing by 40%and 14%,respectively.Furthermore,soluble solids content increased by 4% and vitamin C content rose by 142%,while organic acid content decreased by 30%.Dongkui,however,showed more modest responses under identical conditions,with fruit weight increasing by 2% and fruit size decreasing by 1%.Soluble solids and vitamin C contents showed minimal increases of 2% and 2.5%,respectively,while organic acid content decreased by 8%.The findings demonstrate that supplemental LED lighting significantly enhances both yield and quality parameters in Black Charcoal compared with Dongkui.These results provide valuable insights for optimizing Chinese bayberry cultivation,and the precise control methodology developed can be used to improve supplemental lighting strategies in other fruit and plant species.展开更多
The rapid expansion of urbanization has led to widespread exposure of wild birds to intensive light at night(LAN).While previous studies have established LAN-induced cognitive impairment in birds,the underlying neurob...The rapid expansion of urbanization has led to widespread exposure of wild birds to intensive light at night(LAN).While previous studies have established LAN-induced cognitive impairment in birds,the underlying neurobiological mechanisms remain poorly understood.We hypothesized that LAN exposure impaired cognitive function of birds potentially through neurodegeneration,metabolic dysregulation and neuroinflammatory responses in the telencephalon.Using Zebra Finches(Taeniopygia guttata)as an avian model,under 16L:8D photoperiods,we compared associative learning and memory abilities and neurobiological parameters between experimental groups exposed to dim light at night(LAN)versus nocturnal darkness(CTR).Compared to the CTR birds,the LAN-exposed birds exhibited significantly lower learning and memory performances,reduced neuron density and simplified dendritic morphology in the telencephalons.The key energy metabolic substrates(cholic acid,CTP,D-mannose-6-phosphate)and neuroprotective agents(trehalose,menaquinone,L-gulono-1,4-lactone)in the telencephalons of LAN-exposed birds showed depletion,while oxidative stress markers(methionine sulfoxide)and inflammatory mediators(cis-gondoic acid)exhibited elevation.The neurotransmitter dopamine and histamine metabolic pathway were disrupted in the LAN-exposed birds.The microglias were activated with pro-inflammatory IL-1βand IL-6 levels increasing and anti-inflammatory IL-10 decreasing in the telencephalons of the LAN-exposed birds.These findings indicate a potential mechanistic pathway whereby dim light exposure at night can induce neuroinflammation through oxidative stress-mediated microglial activation,energy metabolism and neurotransmitter homeostasis disruption,ultimately leading to neurodegeneration in the telencephalons of birds.展开更多
Currently,most conventional street lighting systems use a constant light mode throughout the entire night,fromsunset to sunrise,which results in high energy consumption and maintenance costs.Furthermore,scientific res...Currently,most conventional street lighting systems use a constant light mode throughout the entire night,fromsunset to sunrise,which results in high energy consumption and maintenance costs.Furthermore,scientific research predicts that energy consumption for street lighting will increase in the coming years due to growing demand and rising electricity prices.The dimming strategy is a current trend and a key concept in smart street lighting systems.It involves turning on the road lights only when a vehicle or pedestrian is detected;otherwise,the control system reduces the light intensity of the lamps.Power control is generally implemented using artificial intelligence algorithms such as fuzzy logic,artificial neural networks,or swarm intelligence to manage different events.In our project,the dimming strategy was utilized to reduce costs and energy consumption by at least 48%.This research proposes a standalone photovoltaic plant(SPP)to power a smart street lighting system,which can replace individual solar street lights in a small neighborhood in southwestern Algeria.This design offers advantages such as lower costs and the option to add additional loads a DC pump,a domestic power supply,or technical services to operate the photovoltaic system during the day after charging the storage batteries,especially when there is monthly energy surplus.The energy surplus analyzed in our project ranges from 804 W in January to 4 kW in June,generated by the entire PV installation.To demonstrate the feasibility and reliability of this system,we studied the implementation of the standalone photovoltaic plant,energymanagement,and economic analysis using the Particle SwarmOptimization technique under MATLAB software.展开更多
China’s economy has developed rapidly since its reform and opening-up.However,the different rates of development in various places due to location and policies have led to significant economic differences.Based on th...China’s economy has developed rapidly since its reform and opening-up.However,the different rates of development in various places due to location and policies have led to significant economic differences.Based on the nighttime lighting data of 281 municipal spatial units in China from 2013 to 2021,this study uses spatial autocorrelation,center of gravity shift,and standard deviation ellipse(SDE)analysis to examine the evolution of the spatial pattern of China’s municipal economy.Based on these,it uses a geographically weighted regression(GWR)model to explore the factors influencing the differences in China’s municipal economy and its spatial heterogeneity.The paper reveals the following results.First,China’s municipal economy as a whole shows a growing trend.Second,the SDE shows a“north-south”distribution pattern,and the concentration of China’s economic development has slightly increased,with a significant centripetal distribution.Third,spatial correlation shows spatial positive correlation,the degree of which is increasing,with strong spatial heterogeneity and regional agglomeration.Finally,measuring the influencing factors according to GWR,the industrial structure and education expenditure coefficients generally show a decreasing trend from the southeast coast to the northwest and inland due to the degree of transformation of industrial structure and the lagging effect of education expenditure on economic growth.Conversely,the innovation driver and urban area coefficients show a decreasing trend from the northwest inland to the southeast coast due to the law of diminishing marginal utility of innovation drivers and differences in urbanization development.Government expenditure coefficients show a higher trend in the East and a lower trend in the West due to policy favoritism and market development level.This research can serve as a theoretical reference for China to achieve high-quality development and move toward common prosperity.展开更多
All-inorganic reflective phosphor-in-glass film(PiGF) converter has garnered widespread attentions for high brightness laser-driven white lighting,while its poor color quality and low luminescence stability have been ...All-inorganic reflective phosphor-in-glass film(PiGF) converter has garnered widespread attentions for high brightness laser-driven white lighting,while its poor color quality and low luminescence stability have been inevitable roadblocks.Herein,the bicolor PiGF containing green-emitting Y3Al3.08Ga1.92O12:Ce3+(YAGG) and red-emitting CaAlSiN_(3):Eu^(2+)(CASN) phosphors bonded on Al2O3substrate was prepared for enabling high color quality laser-driven white lighting in reflective configuration.The bicolor PiGF has high quantum efficiency and good structure stability.By optimizing the CASN content,PiGF thickness and Al_(2)O_(3) content,the reflective bicolor PiGF based white laser diode(LD)displays good luminescence performance with a luminous flux of 451.5 lm and a luminous efficacy of142.3 lm/W and high color quality with a color rendering index(CRI) of 85.3 and a correlated color temperature(CCT) of 5177 K under the incident laser power of 3.15 W,and still has excellent luminescence and color stabilities(CRI and CCT) under the continuous laser excitation of 5.61 W,attributed to the good thermal conductivity and high reflectivity of Al_(2)O_(3) substrate and scattering enhancement effect of Al_(2)O_(3) particles.It can be foreseen that the reflective bicolor PiGF converter provides a promising strategy for enabling high quality laser-driven white lighting.展开更多
Solid-state lighting is now developing toward high-power and super-brightness,but is largely limited by the lack of highly robust and efficient color conversion materials that can be survived from high-power or high-p...Solid-state lighting is now developing toward high-power and super-brightness,but is largely limited by the lack of highly robust and efficient color conversion materials that can be survived from high-power or high-power density excitation,typically the red-emitting ones.In this work,we fabricated highly effi-cient and pore-free Sr_(0.5)Ca_(0.5)AlSiN_(3)∶Eu^(2+)(SCASN)red-emitting ceramics by spark plasma sintering of fine phosphor powders.These fine phosphor powders were prepared by treating the commercial phosphors with high-energy ball-milling,centrifugation and acid washing,leading to a particle size of 2.55μm and an internal quantum efficiency as high as 74.0%under 450 nm excitation.The phosphor powders can be densified into SCASN ceramics without using sintering additives at a temperature as low as 1475℃,and the ceramics show an internal quantum efficiency of 75.3%,which is 50%higher than those ceram-ics fabricated with untreated commercial powders.When excited by a high-power blue LED at a current density of 4 A/mm^(2),the SCASN ceramics have a maximum luminous flux of 660 lm(i.e.,26 Mcd/m^(2)).The phosphor ceramics can also withstand a high laser power density of 15.7 W/mm^(2),and exhibit an output luminance of 188 Mcd/m^(2).This work provides a general method to prepare fine phosphor powders that enable to fabricate high efficiency phosphor ceramics used in high-power solid-state lighting.展开更多
The visual noise of each light intensity area is different when the image is drawn by Monte Carlo method.However,the existing denoising algorithms have limited denoising performance under complex lighting conditions a...The visual noise of each light intensity area is different when the image is drawn by Monte Carlo method.However,the existing denoising algorithms have limited denoising performance under complex lighting conditions and are easy to lose detailed information.So we propose a rendered image denoising method with filtering guided by lighting information.First,we design an image segmentation algorithm based on lighting information to segment the image into different illumination areas.Then,we establish the parameter prediction model guided by lighting information for filtering(PGLF)to predict the filtering parameters of different illumination areas.For different illumination areas,we use these filtering parameters to construct area filters,and the filters are guided by the lighting information to perform sub-area filtering.Finally,the filtering results are fused with auxiliary features to output denoised images for improving the overall denoising effect of the image.Under the physically based rendering tool(PBRT)scene and Tungsten dataset,the experimental results show that compared with other guided filtering denoising methods,our method improves the peak signal-to-noise ratio(PSNR)metrics by 4.2164 dB on average and the structural similarity index(SSIM)metrics by 7.8%on average.This shows that our method can better reduce the noise in complex lighting scenesand improvethe imagequality.展开更多
The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green ph...The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green phosphor Ba_(2)Sc_(2)((BO_(3))_(2)B_(2)O_(5)):Ce^(3+)(BSBO:Ce^(3+))that can be utilized for full-spectrum lighting and low-temperature sensors.BSBO:Ce^(3+)exhibits a broad-band excitation spectrum centered at 410 nm,and a broad-band emission spectrum centered at 525 nm.The internal and external quantum efficiencies of BSBO:Ce^(3+)are 99%and 49%,respectively.The thermal stability of BSBO:Ce^(3+)can be improved by substituting partial Sc atoms with smaller cations.The thermal quenching mechanism of BSBO:Ce^(3+)and the lattice occupancy of Ce ions in BSBO are discussed in detail.Furthermore,by combining the green phosphor BSBO:Ce^(3+),the commercial blue phosphor and the red phosphor on a 405 nm chip,a white light source was obtained with a high average color rendering index(CRI)of 96.6,a low correlated color temperature(CCT)of 3988 K,and a high luminous efficacy of 88.0 Im/W.The lu-minous efficacy of the WLED exhibits negligible degradation during the 1000 h light aging experiment.What's more,an emission peak at 468 nm appears when excited at 352 nm and 80 K,however,the relative intensity of the peaks at 468 and 525 nm gradually weakens with increasing temperature,indicating the potential of this material as a low-temperature sensor.展开更多
Lutetium aluminum garnet doped with cerium(LuAG:Ce)thin films have been identified as a promising material for high-power laser-driven lighting applications.In this study,spray pyrolysis we employed to fabricate LuAG:...Lutetium aluminum garnet doped with cerium(LuAG:Ce)thin films have been identified as a promising material for high-power laser-driven lighting applications.In this study,spray pyrolysis we employed to fabricate LuAG:Ce films on sapphire substrates and the impact of film thickness on thermal management and light emission efficiency was investigated.Our results show that,regardless of thickness,LuAGiCe films exhibit impressive internal quantum efficiencies(IQE)exceeding 83.2%and external quantum efficiencies(EQE)surpassing 56.4%,with minimal alteration of luminescent color.Notably,thinner films facilitate more efficient heat dissipation to the underlying sapphire substrate,resulting in superior thermal management and outstanding luminous performance under high-power laser excitation.Specifically,the thinnest LuAG:Ce film(15.79μm)exhibited rapid thermal stabilization(~130℃ within 30s)and maintained stability during continuous irradiation lasting 30 min,with a corresponding decrease in luminous flux to 87.9%of its initial value within the first 60 s.This film also demonstrated relatively high and stable conversion efficiency and luminous efficiency,achieving higher saturation thresholds(15 W·mm^(-2))and luminous flux(1070 lm).In contrast,thicker films exhibited a shift in the saturation point toward lower power densities.These findings provide valuable insights for the practical implementation of LuAG:Ce films in advanced lighting technologies.展开更多
Sleep quality in young adults is compromised. Instead of the recommended 7 hours, young adults’ schedule interruptions disturb sleep to a typical six and a half hours, with common disturbances in falling asleep and s...Sleep quality in young adults is compromised. Instead of the recommended 7 hours, young adults’ schedule interruptions disturb sleep to a typical six and a half hours, with common disturbances in falling asleep and staying asleep. Recent literature has identified an association between academic performance, negative mood state and low activity level in young adults with sleep disturbances. Young adulthood is a time for the installation of sleep health. Both individual and schedule impositions to the young adults’ sleep schedule are to be modified to obtain Sleep Health. Recent research has identified daytime light effects on sleep such as blue light from electronics as alerting and low level light for relaxation. The aim of this study was to identify sleep quality effects with varying light exposures. It was hypothesized that bright (>450 lux) light conditions would be considered focusing and low light (<220 lux) would be considered calming. We hypothesized that sleep quality would improve by 5% with the introduction of a calm light condition. Undergraduates from a small midwestern university were invited to participate in the study in exchange for a gift card. Six participants completed the study, two males, four females all between 21 - 24 years old. Both hypotheses were supported by qualitative analysis.展开更多
The pursuit of high-brightness solid-state lighting(SSL)stimulates the development of all-inorganic color converters with high robustness.It is required that the fluorescent material is able to cope with the extreme c...The pursuit of high-brightness solid-state lighting(SSL)stimulates the development of all-inorganic color converters with high robustness.It is required that the fluorescent material is able to cope with the extreme condition generated from the irradiation of high-power-density excitation light.As such,in this work,we developed a new composite color converter,i,e.,Y_(3)Al_(5)O_(12):Ce^(3+)phosphor-in-silica glass ceramic(YAG:Ce^(3+)PiSGC).Remarkably,the amorphous SiO_(2)matrix spontaneously transforms into tetragonal SiO_(2)crystallites during co-sintering with crystallization fraction reaching up to>90%(almost full ceramization).The activation energy for crystallization E_(c)and Avrami index n of amorphous silica oxide are 298.5 kJ/mol and 1.71,indicating the diffusion-controlled glass crystallization mechanism.The fabricated prototype high-power phosphor-converted white light-emitting diode(pc-wLED)and phosphor-converted white laser diode(pc-wLD)based on YAG:Ce^(3+)PiSGC show satisfactory photometric/colorimetric parameters.The developed color co nverters have combined merits of environmental protection property,cost-effective manufacturing,good luminescent performance,and easy scalability.This study highlights a new kind of opto-functional composite material and its application as an efficient color converter in high-power solid-state lightings.展开更多
Advanced machine vision provides a direct and fast approach to perceive the external environment,enabling the rapid development in the state-of-art automatic driving,environmental monitoring,and human-machine interact...Advanced machine vision provides a direct and fast approach to perceive the external environment,enabling the rapid development in the state-of-art automatic driving,environmental monitoring,and human-machine interaction,etc.However,detecting and recognizing objects from complex backgrounds usually requires high dynamic range imaging and complex algorithms,raising tremedous challenging in further reducing the size,weight,and power(SWaP)in sensory system.Once the target object and background are easily distinguished at the sensor hardware level,a great deal of computational resources and power consumption can be saved[1,2].展开更多
文摘Background:Irregular heartbeats can have serious health implications if left undetected and untreated for an extended period of time.Methods:This study leverages machine learning(ML)techniques to classify electrocardiogram(ECG)heartbeats,comparing traditional feature-based ML methods with innovative image-based approaches.The dataset underwent rigorous preprocessing,including down-sampling,frequency filtering,beat segmentation,and normalization.Two methodologies were explored:(1)handcrafted feature extraction,utilizing metrics like heart rate variability and RR distances with LightGBM classifiers,and(2)image transformation of ECG signals using Gramian Angular Field(GAF),Markov Transition Field(MTF),and Recurrence Plot(RP),enabling multimodal input for convolutional neural networks(CNNs).The Synthetic Minority Oversampling Technique(SMOTE)addressed data imbalance,significantly improving minority-class metrics.Results:The handcrafted feature approach achieved notable performance,with LightGBM excelling in precision and recall.Image-based classification further enhanced outcomes,with a custom Inception-based CNN,attaining an 85%F1 score and 97%accuracy using combined GAF,MTF,and RP transformations.Statistical analyses confirmed the significance of these improvements.Conclusion:This work highlights the potential of ML for cardiac irregularities detection,demonstrating that combining advanced preprocessing,feature engineering,and state-of-the-art neural networks can improve classification accuracy.These findings contribute to advancing AI-driven diagnostic tools,offering promising implications for cardiovascular healthcare.
基金2024 Science and Technology Commissioner Service Group's Emergency Science and Technology Research Project for Wind Disaster Relief in Hainan Province(ZDYF2024YJGG002-8)China Huaneng Group Co.,Ltd.Headquarters Technology Project,Optimization of Photovoltaic Vegetable Greenhouse Structure and Research on Planting Agronomy in Tropical Regions(HNKJ22-HF77)。
文摘In the tropical regions represented by Hainan,there are abundant solar and thermal resources,and it is relatively suitable for the construction of photovoltaic greenhouse(PVG).However,the construction of PVG still relies mainly on experience and is incapable of quantifying the balance between the photovoltaic(PV)generation and the light requirements for agricultural production.As a result,actual PVGs are primarily PV-based,without carefully considering the needs of agricultural daylighting.To quantify the influence of the design parameters of PVGs and the layout of PV panels on the internal daylighting of serrated PVGs,and to optimize the daylighting design of the roof,this paper utilizes the Design Builder software to establish gradient models for a multi-span serrated-type PVG in tropical regions.Gradient models were established in terms of aspects,namely span,width of longitudinal/transverse daylighting strip,height,roof angle,and photovoltaic panel coverage rate(PCR).Daylighting in the greenhouse of each gradient model was simulated,and with the annual average daily light integral(A_(DLI))and distribution uniformity(DU)as evaluation indicators,the influence of various design parameters on the daylighting inside the greenhouse was quantified.The result reveals that:(1)PCR is the decisive indicator for daylighting in the PVG,and a function between PCR and the A_(DLI) is derived as A_(DLI)=-15.5 PCR+16.841;(2)Increasing the width of longitudinal daylighting strip significantly improves the A_(DLI) and enhances DU while increasing the span has a noticeable effect on improving A_(DLI) but does not significantly enhance DU;(3)Increasing the eave height without changing PCR does not enhance A_(DLI) but effectively improves DU;increasing the transverse daylighting strip and adjusting the roof angle hardly improves A_(DLI).In summary,it is recommended that the optimal span for PVGs in tropical regions be set within the range of 6.5-8.0m,and the eave height be set within the range of 2.5-3.5m.Preferably,the longitudinal daylighting strip with a width ranging from 0.5-0.8m should be installed.Based on the above relationship function,the PCR can be calculated according to the appropriate light demand for the cultivated crops.The daylighting design theory proposed in this paper can provide a theoretical basis and reference for the healthy development of the PV industry in tropical regions.
基金funded by the Doctor Foundation of Southwest University of Science and Technology,grant number:24zx7116.
文摘Supplemental lighting has emerged as a widely adopted technique in greenhouse cultivation to enhance product visibility andimprove theflavor characteristics ofChinese bayberry(Myrica rubra)in the internationalmarket.While studies on lighting have predominantly focused on colorimetry,limited research has addressed the precise control of chromatic parameters and their effect on fruit quality.This study examined the effects of varying lighting conditions,specifically correlated color temperatures and illuminance,on the growth and quality of Chinese bayberry varieties“Black Charcoal”and“Dongkui”using a precision control system.The bayberry plants were exposed to a constant illuminance of 155μmol·m^(-2)·s^(-1) with chromatic levels ranging from 2250 to 6000 K.Black Charcoal demonstrated substantial improvements under different chromatic parameters,with fruit weight and size increasing by 40%and 14%,respectively.Furthermore,soluble solids content increased by 4% and vitamin C content rose by 142%,while organic acid content decreased by 30%.Dongkui,however,showed more modest responses under identical conditions,with fruit weight increasing by 2% and fruit size decreasing by 1%.Soluble solids and vitamin C contents showed minimal increases of 2% and 2.5%,respectively,while organic acid content decreased by 8%.The findings demonstrate that supplemental LED lighting significantly enhances both yield and quality parameters in Black Charcoal compared with Dongkui.These results provide valuable insights for optimizing Chinese bayberry cultivation,and the precise control methodology developed can be used to improve supplemental lighting strategies in other fruit and plant species.
基金supported by grants from Key laboratory of Ecology and Environment in Minority Area,National Ethnic Affairs Commission(KLEEMA202207)。
文摘The rapid expansion of urbanization has led to widespread exposure of wild birds to intensive light at night(LAN).While previous studies have established LAN-induced cognitive impairment in birds,the underlying neurobiological mechanisms remain poorly understood.We hypothesized that LAN exposure impaired cognitive function of birds potentially through neurodegeneration,metabolic dysregulation and neuroinflammatory responses in the telencephalon.Using Zebra Finches(Taeniopygia guttata)as an avian model,under 16L:8D photoperiods,we compared associative learning and memory abilities and neurobiological parameters between experimental groups exposed to dim light at night(LAN)versus nocturnal darkness(CTR).Compared to the CTR birds,the LAN-exposed birds exhibited significantly lower learning and memory performances,reduced neuron density and simplified dendritic morphology in the telencephalons.The key energy metabolic substrates(cholic acid,CTP,D-mannose-6-phosphate)and neuroprotective agents(trehalose,menaquinone,L-gulono-1,4-lactone)in the telencephalons of LAN-exposed birds showed depletion,while oxidative stress markers(methionine sulfoxide)and inflammatory mediators(cis-gondoic acid)exhibited elevation.The neurotransmitter dopamine and histamine metabolic pathway were disrupted in the LAN-exposed birds.The microglias were activated with pro-inflammatory IL-1βand IL-6 levels increasing and anti-inflammatory IL-10 decreasing in the telencephalons of the LAN-exposed birds.These findings indicate a potential mechanistic pathway whereby dim light exposure at night can induce neuroinflammation through oxidative stress-mediated microglial activation,energy metabolism and neurotransmitter homeostasis disruption,ultimately leading to neurodegeneration in the telencephalons of birds.
文摘Currently,most conventional street lighting systems use a constant light mode throughout the entire night,fromsunset to sunrise,which results in high energy consumption and maintenance costs.Furthermore,scientific research predicts that energy consumption for street lighting will increase in the coming years due to growing demand and rising electricity prices.The dimming strategy is a current trend and a key concept in smart street lighting systems.It involves turning on the road lights only when a vehicle or pedestrian is detected;otherwise,the control system reduces the light intensity of the lamps.Power control is generally implemented using artificial intelligence algorithms such as fuzzy logic,artificial neural networks,or swarm intelligence to manage different events.In our project,the dimming strategy was utilized to reduce costs and energy consumption by at least 48%.This research proposes a standalone photovoltaic plant(SPP)to power a smart street lighting system,which can replace individual solar street lights in a small neighborhood in southwestern Algeria.This design offers advantages such as lower costs and the option to add additional loads a DC pump,a domestic power supply,or technical services to operate the photovoltaic system during the day after charging the storage batteries,especially when there is monthly energy surplus.The energy surplus analyzed in our project ranges from 804 W in January to 4 kW in June,generated by the entire PV installation.To demonstrate the feasibility and reliability of this system,we studied the implementation of the standalone photovoltaic plant,energymanagement,and economic analysis using the Particle SwarmOptimization technique under MATLAB software.
基金funded by the Project of Philosophy and Social Science Key Research Base−Industrial Transformation and Innovation Research Center of Zigong Municipal Federation of Social Sciences[Grant No.CZ23B02].
文摘China’s economy has developed rapidly since its reform and opening-up.However,the different rates of development in various places due to location and policies have led to significant economic differences.Based on the nighttime lighting data of 281 municipal spatial units in China from 2013 to 2021,this study uses spatial autocorrelation,center of gravity shift,and standard deviation ellipse(SDE)analysis to examine the evolution of the spatial pattern of China’s municipal economy.Based on these,it uses a geographically weighted regression(GWR)model to explore the factors influencing the differences in China’s municipal economy and its spatial heterogeneity.The paper reveals the following results.First,China’s municipal economy as a whole shows a growing trend.Second,the SDE shows a“north-south”distribution pattern,and the concentration of China’s economic development has slightly increased,with a significant centripetal distribution.Third,spatial correlation shows spatial positive correlation,the degree of which is increasing,with strong spatial heterogeneity and regional agglomeration.Finally,measuring the influencing factors according to GWR,the industrial structure and education expenditure coefficients generally show a decreasing trend from the southeast coast to the northwest and inland due to the degree of transformation of industrial structure and the lagging effect of education expenditure on economic growth.Conversely,the innovation driver and urban area coefficients show a decreasing trend from the northwest inland to the southeast coast due to the law of diminishing marginal utility of innovation drivers and differences in urbanization development.Government expenditure coefficients show a higher trend in the East and a lower trend in the West due to policy favoritism and market development level.This research can serve as a theoretical reference for China to achieve high-quality development and move toward common prosperity.
基金Project supported by the Science and Technology Project of Shenzhen City (JSGG20210802154213040)the Guangdong Basic and Applied Basic Research Foundation (2024A1515010001)the Shenzhen Postdoctoral Research Funding Project。
文摘All-inorganic reflective phosphor-in-glass film(PiGF) converter has garnered widespread attentions for high brightness laser-driven white lighting,while its poor color quality and low luminescence stability have been inevitable roadblocks.Herein,the bicolor PiGF containing green-emitting Y3Al3.08Ga1.92O12:Ce3+(YAGG) and red-emitting CaAlSiN_(3):Eu^(2+)(CASN) phosphors bonded on Al2O3substrate was prepared for enabling high color quality laser-driven white lighting in reflective configuration.The bicolor PiGF has high quantum efficiency and good structure stability.By optimizing the CASN content,PiGF thickness and Al_(2)O_(3) content,the reflective bicolor PiGF based white laser diode(LD)displays good luminescence performance with a luminous flux of 451.5 lm and a luminous efficacy of142.3 lm/W and high color quality with a color rendering index(CRI) of 85.3 and a correlated color temperature(CCT) of 5177 K under the incident laser power of 3.15 W,and still has excellent luminescence and color stabilities(CRI and CCT) under the continuous laser excitation of 5.61 W,attributed to the good thermal conductivity and high reflectivity of Al_(2)O_(3) substrate and scattering enhancement effect of Al_(2)O_(3) particles.It can be foreseen that the reflective bicolor PiGF converter provides a promising strategy for enabling high quality laser-driven white lighting.
基金supported by the National Key Research and Development Program(MOST,No.2022YFE0108800)the National Natural Science Foundation of China(Nos.52272165,U2005213 and 52172157)the Major Science and Technology Projects of Xiamen Science and Technology Bureau(No.3502Z20231018).
文摘Solid-state lighting is now developing toward high-power and super-brightness,but is largely limited by the lack of highly robust and efficient color conversion materials that can be survived from high-power or high-power density excitation,typically the red-emitting ones.In this work,we fabricated highly effi-cient and pore-free Sr_(0.5)Ca_(0.5)AlSiN_(3)∶Eu^(2+)(SCASN)red-emitting ceramics by spark plasma sintering of fine phosphor powders.These fine phosphor powders were prepared by treating the commercial phosphors with high-energy ball-milling,centrifugation and acid washing,leading to a particle size of 2.55μm and an internal quantum efficiency as high as 74.0%under 450 nm excitation.The phosphor powders can be densified into SCASN ceramics without using sintering additives at a temperature as low as 1475℃,and the ceramics show an internal quantum efficiency of 75.3%,which is 50%higher than those ceram-ics fabricated with untreated commercial powders.When excited by a high-power blue LED at a current density of 4 A/mm^(2),the SCASN ceramics have a maximum luminous flux of 660 lm(i.e.,26 Mcd/m^(2)).The phosphor ceramics can also withstand a high laser power density of 15.7 W/mm^(2),and exhibit an output luminance of 188 Mcd/m^(2).This work provides a general method to prepare fine phosphor powders that enable to fabricate high efficiency phosphor ceramics used in high-power solid-state lighting.
基金supported by the National Natural Science(No.U19A2063)the Jilin Provincial Development Program of Science and Technology (No.20230201080GX)the Jilin Province Education Department Scientific Research Project (No.JJKH20230851KJ)。
文摘The visual noise of each light intensity area is different when the image is drawn by Monte Carlo method.However,the existing denoising algorithms have limited denoising performance under complex lighting conditions and are easy to lose detailed information.So we propose a rendered image denoising method with filtering guided by lighting information.First,we design an image segmentation algorithm based on lighting information to segment the image into different illumination areas.Then,we establish the parameter prediction model guided by lighting information for filtering(PGLF)to predict the filtering parameters of different illumination areas.For different illumination areas,we use these filtering parameters to construct area filters,and the filters are guided by the lighting information to perform sub-area filtering.Finally,the filtering results are fused with auxiliary features to output denoised images for improving the overall denoising effect of the image.Under the physically based rendering tool(PBRT)scene and Tungsten dataset,the experimental results show that compared with other guided filtering denoising methods,our method improves the peak signal-to-noise ratio(PSNR)metrics by 4.2164 dB on average and the structural similarity index(SSIM)metrics by 7.8%on average.This shows that our method can better reduce the noise in complex lighting scenesand improvethe imagequality.
基金the National Natural Science Foundation of China(22003035,21963006,22073061)the Project of Shaanxi Province Youth Science and Technology New Star(2023KJXX-076)the National Training Program of Innovation and Entrepreneurship for Undergraduates(202314390018)。
文摘The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green phosphor Ba_(2)Sc_(2)((BO_(3))_(2)B_(2)O_(5)):Ce^(3+)(BSBO:Ce^(3+))that can be utilized for full-spectrum lighting and low-temperature sensors.BSBO:Ce^(3+)exhibits a broad-band excitation spectrum centered at 410 nm,and a broad-band emission spectrum centered at 525 nm.The internal and external quantum efficiencies of BSBO:Ce^(3+)are 99%and 49%,respectively.The thermal stability of BSBO:Ce^(3+)can be improved by substituting partial Sc atoms with smaller cations.The thermal quenching mechanism of BSBO:Ce^(3+)and the lattice occupancy of Ce ions in BSBO are discussed in detail.Furthermore,by combining the green phosphor BSBO:Ce^(3+),the commercial blue phosphor and the red phosphor on a 405 nm chip,a white light source was obtained with a high average color rendering index(CRI)of 96.6,a low correlated color temperature(CCT)of 3988 K,and a high luminous efficacy of 88.0 Im/W.The lu-minous efficacy of the WLED exhibits negligible degradation during the 1000 h light aging experiment.What's more,an emission peak at 468 nm appears when excited at 352 nm and 80 K,however,the relative intensity of the peaks at 468 and 525 nm gradually weakens with increasing temperature,indicating the potential of this material as a low-temperature sensor.
基金financially supported by the National Natural Science Foundation of China(Nos.51977027 and 51967008)the Scientific and Technological Project of Yunnan Precious Metals Laboratory(Nos.YPML-2023050250 and YPML-2022050206)。
文摘Lutetium aluminum garnet doped with cerium(LuAG:Ce)thin films have been identified as a promising material for high-power laser-driven lighting applications.In this study,spray pyrolysis we employed to fabricate LuAG:Ce films on sapphire substrates and the impact of film thickness on thermal management and light emission efficiency was investigated.Our results show that,regardless of thickness,LuAGiCe films exhibit impressive internal quantum efficiencies(IQE)exceeding 83.2%and external quantum efficiencies(EQE)surpassing 56.4%,with minimal alteration of luminescent color.Notably,thinner films facilitate more efficient heat dissipation to the underlying sapphire substrate,resulting in superior thermal management and outstanding luminous performance under high-power laser excitation.Specifically,the thinnest LuAG:Ce film(15.79μm)exhibited rapid thermal stabilization(~130℃ within 30s)and maintained stability during continuous irradiation lasting 30 min,with a corresponding decrease in luminous flux to 87.9%of its initial value within the first 60 s.This film also demonstrated relatively high and stable conversion efficiency and luminous efficiency,achieving higher saturation thresholds(15 W·mm^(-2))and luminous flux(1070 lm).In contrast,thicker films exhibited a shift in the saturation point toward lower power densities.These findings provide valuable insights for the practical implementation of LuAG:Ce films in advanced lighting technologies.
文摘Sleep quality in young adults is compromised. Instead of the recommended 7 hours, young adults’ schedule interruptions disturb sleep to a typical six and a half hours, with common disturbances in falling asleep and staying asleep. Recent literature has identified an association between academic performance, negative mood state and low activity level in young adults with sleep disturbances. Young adulthood is a time for the installation of sleep health. Both individual and schedule impositions to the young adults’ sleep schedule are to be modified to obtain Sleep Health. Recent research has identified daytime light effects on sleep such as blue light from electronics as alerting and low level light for relaxation. The aim of this study was to identify sleep quality effects with varying light exposures. It was hypothesized that bright (>450 lux) light conditions would be considered focusing and low light (<220 lux) would be considered calming. We hypothesized that sleep quality would improve by 5% with the introduction of a calm light condition. Undergraduates from a small midwestern university were invited to participate in the study in exchange for a gift card. Six participants completed the study, two males, four females all between 21 - 24 years old. Both hypotheses were supported by qualitative analysis.
基金Project supported by the National Natural Science Foundation of China(U2005213,51972303,11974350)Science Fund for Distinguished Young Scholars of Fujian Province(2022J06030)+2 种基金Science Fund of Fujian Province(2022J05091)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR134)the STS Project of Fujian-CAS(2022T3069)。
文摘The pursuit of high-brightness solid-state lighting(SSL)stimulates the development of all-inorganic color converters with high robustness.It is required that the fluorescent material is able to cope with the extreme condition generated from the irradiation of high-power-density excitation light.As such,in this work,we developed a new composite color converter,i,e.,Y_(3)Al_(5)O_(12):Ce^(3+)phosphor-in-silica glass ceramic(YAG:Ce^(3+)PiSGC).Remarkably,the amorphous SiO_(2)matrix spontaneously transforms into tetragonal SiO_(2)crystallites during co-sintering with crystallization fraction reaching up to>90%(almost full ceramization).The activation energy for crystallization E_(c)and Avrami index n of amorphous silica oxide are 298.5 kJ/mol and 1.71,indicating the diffusion-controlled glass crystallization mechanism.The fabricated prototype high-power phosphor-converted white light-emitting diode(pc-wLED)and phosphor-converted white laser diode(pc-wLD)based on YAG:Ce^(3+)PiSGC show satisfactory photometric/colorimetric parameters.The developed color co nverters have combined merits of environmental protection property,cost-effective manufacturing,good luminescent performance,and easy scalability.This study highlights a new kind of opto-functional composite material and its application as an efficient color converter in high-power solid-state lightings.
文摘Advanced machine vision provides a direct and fast approach to perceive the external environment,enabling the rapid development in the state-of-art automatic driving,environmental monitoring,and human-machine interaction,etc.However,detecting and recognizing objects from complex backgrounds usually requires high dynamic range imaging and complex algorithms,raising tremedous challenging in further reducing the size,weight,and power(SWaP)in sensory system.Once the target object and background are easily distinguished at the sensor hardware level,a great deal of computational resources and power consumption can be saved[1,2].
