期刊文献+
共找到102,402篇文章
< 1 2 250 >
每页显示 20 50 100
Round-the-Clock Photocatalysts in the Post-Irradiation Dark Period:From Light Charging to“Memory”Dark Discharging Toward Hydrogen Production
1
作者 Balvinder Kaur Pardeep Singh +5 位作者 Duc Anh Dinh Xuan-Cuong Luu Krishna Kumar Yadav Maha Awjan Alreshidi Van-Huy Nguyen Pankaj Raizada 《Transactions of Tianjin University》 2025年第6期645-668,共24页
The intermittent nature of solar irradiance is a critical constraint for the realization of continuous photocatalytic hydrogen evolution,thus urging the development of more powerful systems persistently active after i... The intermittent nature of solar irradiance is a critical constraint for the realization of continuous photocatalytic hydrogen evolution,thus urging the development of more powerful systems persistently active after illumination.This limitation is bypassed in round-the-clock photocatalytic architectures,which incorporate advanced charge storage to de-correlate pho-ton absorption and catalytic turnover time scales.The strategies involve defect-mediated trap states,multi-electron redox processes,radical-dependent stabilization,and an interfacial charge pool in Faradaic junctions to work together,leading to extended hydrogen evolution reaction(HER)in the dark.Long afterglow phosphorescent materials(e.g.,Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+))incorporated in heterojunction architectures with type II or Z-scheme band alignments can also promote fast charge separation for energy storage and subsequently enable controlled release after light quenching by the phosphorescent emis-sion.Advances in band-structure engineering,plasmonic coupling,and redox-active interfacial design result in systems with extraordinary stability and catalytic activity under natural day-night cycles.These stable photocatalytic systems off er a fundamentally new strategy for effi cient and environmentally benign sunlight-driven fuel production,meeting both per-formance and sustainability challenges to renewable energy technologies. 展开更多
关键词 Round-the-clock photocatalysis dark hydrogen evolution Charge storage Memory effect Persistent luminescence materials
在线阅读 下载PDF
Tailoring a Back-Contact Barrier for a Self-Powered Broadband Kesterite Photodetector With Ultralow Dark Current Enabling Ultra-Weak-Light Detection
2
作者 Qianfeng Wu Chuanhao Li +7 位作者 Shuo Chen Zhenghua Su Muhammad Abbas Chao Chen Qianqian Lin Jingting Luo Liming Ding Guangxing Liang 《Carbon Energy》 2025年第5期35-44,共10页
Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by hig... Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by high dark current,which can greatly reduce their performance and sensitivity,thereby limiting their effectiveness in certain applications.In this work,the introduction of a C60 back interface layer successfully mitigated back interface reactions to decrease the thickness of the Mo(S,Se)_(2)layer,tailoring the back-contact barrier and preventing reverse charge injection,resulting in a kesterite photodetector with an ultralow dark current density of 5.2×10^(-9)mA/cm^(2)and ultra-weak-light detection at levels as low as 25 pW/cm^(2).Besides,under a self-powered operation,it demonstrates outstanding performance,achieving a peak responsivity of 0.68 A/W,a wide response range spanning from 300 to 1600 nm,and an impressive detectivity of 5.27×10^(14)Jones.In addition,it offers exceptionally rapid response times,with rise and decay times of 70 and 650 ns,respectively.This research offers important insights for developing high-performance self-powered near-infrared photodetectors that have high responsivity,rapid response times,and ultralow dark current. 展开更多
关键词 DETECTIVITY KESTERITE PHOTODETECTOR thin film weak light detection
在线阅读 下载PDF
DarkTiny-YOLO:低光照场景下无人机航拍小目标检测算法
3
作者 赵森 赵健康 +1 位作者 龙海辉 刘传奇 《电光与控制》 北大核心 2026年第2期20-26,34,共8页
针对无人机在低光照场景下航拍任务中目标检测面临的光照不足、目标尺寸小以及背景复杂等挑战,提出了基于YOLOv11s的改进模型DarkTiny-YOLO。该模型首先通过轻量化自校正亮度增强模块(Li-SCBM)动态调整图像亮度,增强目标特征表达;其次,... 针对无人机在低光照场景下航拍任务中目标检测面临的光照不足、目标尺寸小以及背景复杂等挑战,提出了基于YOLOv11s的改进模型DarkTiny-YOLO。该模型首先通过轻量化自校正亮度增强模块(Li-SCBM)动态调整图像亮度,增强目标特征表达;其次,利用轻量化特征金字塔网络(Tiny-FPN),通过引入上下文锚点注意力机制和优化C3k2模块,降低计算成本的同时提高检测精度;最后,采用优化的多尺度小目标动态检测头(MSD-ODHead),加强小目标的识别能力并提升模型在多尺度场景下的检测性能。实验结果表明,DarkTiny-YOLO在VisDrone2019数据集上,相比YOLOv11s算法,mAP指标提升超过0.1,对低光照场景下的小目标检测性能显著提高。 展开更多
关键词 小目标检测 低光照场景 无人机航拍 YOLOv11s
在线阅读 下载PDF
Comparing the Indoor and Solar Performance of Light-Concentrating Waveguide-Encoded Lattice Slim Films
4
作者 Takashi Lawson Kathryn A.Benincasa +7 位作者 Anjilee Manhas Fariha Mahmood Helen Tunstall-García Zhihang Wang Zhongjin Shen Marina Freitag Kalaichelvi Saravanamuttu Rachel C.Evans 《Carbon Energy》 2026年第1期187-196,共10页
Although multicrystalline Si photovoltaics have been extensively studied and applied in the collection of solar energy,the same systems suffer significant efficiency losses in indoor settings,where ambient light condi... Although multicrystalline Si photovoltaics have been extensively studied and applied in the collection of solar energy,the same systems suffer significant efficiency losses in indoor settings,where ambient light conditions are considerably smaller in intensity and possess greater components of non-normal incidence.Yet,indoor light-driven,stand-alone devices can offer sustainable advances in next-generation technologies such as the Internet of Things.Here,we present a non-invasive solution to aid in photovoltaic indoor light collection—radially distributed waveguide-encoded lattice(RDWEL)slim films(thickness 1.5 mm).Embedded with a monotonical radial array of cylindrical waveguides(±20°),the RDWEL demonstrates seamless light collection(FoV(fields of view)=74.5°)and imparts enhancements in JSC(short circuit current density)of 44%and 14%for indoor and outdoor lighting conditions,respectively,when coupled to a photovoltaic device and compared to an unstructured but otherwise identical slim film coating. 展开更多
关键词 indoor light light concentrators optical thin films PHOTOPATTERNING photovoltaics self-induced waveguides solar energy
在线阅读 下载PDF
Achieving dark current suppression and photocurrent enhancement simultaneously in 2D MoS_(2) photodetector via Ag_(70) nanocluster modification
5
作者 Xiao-Zong Hu Jing Li +3 位作者 Huai-Zhen Ji Qian-Fang Ren Xi-Ming Luo Shuang-Quan Zang 《Nano Research》 2026年第1期1102-1110,共9页
Two-dimensional(2D)MoS_(2) is considered an excellent candidate material for nextgeneration photodetectors.However,the high dark current and low photocurrent in MoS_(2) devices severely hinder their practical applicat... Two-dimensional(2D)MoS_(2) is considered an excellent candidate material for nextgeneration photodetectors.However,the high dark current and low photocurrent in MoS_(2) devices severely hinder their practical application.Strategies for suppressing dark current and enhancing photocurrent should be explored.Herein,we propose a modification strategy for MoS_(2) by utilizing Ag_(70) nanoclusters(NCs)as electron reservoirs and photoabsorbers to suppress dark current and enhance the photocurrent of 2D MoS_(2) photodetector.Remarkably,the dark current is effectively suppressed by four orders of magnitude,while the photocurrent is enhanced by over tenfold upon modification with Ag_(70) NCs,compared to the pristine MoS_(2) photodetector.The reduction in dark current is attributed to charge transfer from MoS_(2) to Ag_(70) NCs owing to the strong electronwithdrawing property of Ag_(70) NCs.The increase in photocurrent benefits from enhanced optical absorption of the photodetector after Ag_(70) NCs modification and the subsequent injection of photoexcited electrons from Ag_(70) NCs to MoS_(2).Compared to isolated MoS_(2),the modulated photodetector shows exceptional improvements in several key figures of merit(such as responsivity,detectivity,external quantum efficiency,and photoswitching on/off ratio).This study opens up new avenues for building high-performance 2D MoS_(2) photodetectors. 展开更多
关键词 metal nanocluster MoS_(2)photodetector dark current suppression photocurrent enhancement
原文传递
Improving Efficiency of Light Pressure Electric Generator Using Graphene Oxide Nanospacer Between Ag Nanoparticles
6
作者 Ha Young Lee Sung-Hyun Kim +3 位作者 Sun-Lyeong Hwang Hyung Soo Ahn Heedae Kim Sam Nyung Yi 《Carbon Energy》 2026年第1期38-47,共10页
Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic struct... Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic structure light pressure electric generator(Basic-LPEG),which utilized a layered configuration of Ag/Pb(Zr,Ti)O_(3)(PZT)/Pt/GaAs to generate electricity based on light-induced pressure on the PZT.In this study,we sought to enhance the performance of this Basic-LPEG by introducing Ag nanoparticles/graphene oxide(AgNPs/GO)composite units(NP-LPEG),creating upgraded harvesting device.Specifically,by depositing the AgNPs/GO units twice onto the Basic-LPEG,we observed an increase in output voltage and current from 241 mV and 3.1μA to 310 mV and 9.3μA,respectively,under a solar simulator.The increase in electrical output directly correlated with the intensity of the light pressure impacting the PZT,as well as matched the Raman measurements,finite-difference time-domain simulations,and COMSOL Multiphysics Simulation.Experimental data revealed that the enhancement in electrical output was proportional to the number of hot spots generated between Ag nanoparticles,where the electric field experienced substantial amplification.These results underline the effectiveness of AgNPs/GO units in boosting the light-induced electric generation capacity,thereby providing a promising pathway for high-efficiency energy harvesting devices. 展开更多
关键词 Ag nanoparticles energy harvesting graphene oxide light pressure PIEZOELECTRIC
在线阅读 下载PDF
Pharmacological and light-driven pupillary accommodation in guinea pigs:comparative effects of muscarinic modulators and illumination across developmental stages
7
作者 Hao Wu Na Lu +5 位作者 Zhong-Bao Qiao Chi Cheng Wen-Ting Luo Ting Wan Tong Qiao Yue Di 《International Journal of Ophthalmology(English edition)》 2026年第2期211-218,共8页
AIM:To investigate the effects of different light intensities and various mydriatic and miotic drugs on pupil accommodation in guinea pigs.METHODS:Forty-two-week-old guinea pigs were randomly divided into four groups ... AIM:To investigate the effects of different light intensities and various mydriatic and miotic drugs on pupil accommodation in guinea pigs.METHODS:Forty-two-week-old guinea pigs were randomly divided into four groups to assess pupillary responses under varying light intensities(100,250,500 lx)and pharmacological interventions(1%atropine,1%cyclopentolate,1%tropicamide,or 2%pilocarpine).Baseline pupil size and eccentricity were recorded using a non-contact Python-based imaging system integrating edge detection and pixel-to-distance conversion.Direct illumination effects were measured at sequential time points,followed by drug administration and longitudinal tracking of pupillary changes.The protocol was repeated at 12wk of age for developmental comparisons.Postexperiment,enucleated eyes were analyzed to evaluate in vitro vs in vivo differences.RESULTS:Significant age-dependent differences in pupil dynamics were observed.Both 2-and 12-week-old guinea pigs exhibited marked pupil constriction under direct illumination(P<0.001),with decreased eccentricity post-constriction(P<0.001).Indirect illumination caused inconsistent pupil size changes(2-week:P=0.68;12-week:P=0.49).Pharmacologically,atropine,cyclopentolate,and tropicamide induced pupil dilation(P<0.001),whereas pilocarpine caused constriction(P<0.001).All drug groups showed reduced eccentricity(P<0.001).In vivo/in vitro comparisons revealed significant structural differences.CONCLUSION:This study investigates pupillary responses in developing guinea pigs,revealing a direct pupillary light reflex(PLR)with light intensity-dependent responses,while indirect PLR was undetectable.The differential effects of muscarinic modulators on pupillary responses underscore the critical role of cholinergic signaling in ocular accommodation,with age-related variations in sensitivity.Additionally,a novel non-contact measurement methodology achieved a precision of 0.01 mm for pupillary quantification,enhancing accuracy in ocular studies. 展开更多
关键词 PUPIL guinea pig muscarinic receptor modulator light reflex
原文传递
Bioinspired Precision Peeling of Ultrathin Bamboo Green Cellulose Frameworks for Light Management in Optoelectronics
8
作者 Yan Wang Yuan Zhang +2 位作者 Yingfeng Zuo Dawei Zhao Yiqiang Wu 《Nano-Micro Letters》 2026年第1期474-489,共16页
Cellulose frameworks have emerged as promising materials for light management due to their exceptional light-scattering capabilities and sustainable nature.Conventional biomass-derived cellulose frameworks face a fund... Cellulose frameworks have emerged as promising materials for light management due to their exceptional light-scattering capabilities and sustainable nature.Conventional biomass-derived cellulose frameworks face a fundamental trade-off between haze and transparency,coupled with impractical thicknesses(≥1 mm).Inspired by squid’s skin-peeling mechanism,this work develops a peroxyformic acid(HCOOOH)-enabled precision peeling strategy to isolate intact 10-μm-thick bamboo green(BG)frameworks—100×thinner than wood-based counterparts while achieving an unprecedented optical performance(88%haze with 80%transparency).This performance surpasses delignified biomass(transparency<40%at 1 mm)and matches engineered cellulose composites,yet requires no energy-intensive nanofibrillation.The preserved native cellulose I crystalline structure(64.76%crystallinity)and wax-coated uniaxial fibril alignment(Hermans factor:0.23)contribute to high mechanical strength(903 MPa modulus)and broadband light scattering.As a light-management layer in polycrystalline silicon solar cells,the BG framework boosts photoelectric conversion efficiency by 0.41%absolute(18.74%→19.15%),outperforming synthetic anti-reflective coatings.The work establishes a scalable,waste-to-wealth route for optical-grade cellulose materials in next-generation optoelectronics. 展开更多
关键词 Bamboo green Cellulose framework Chemical peeling Optical properties light management
在线阅读 下载PDF
Visible light photocatalytic enhanced heterogeneous cobalt catalyzed peroxymonosulfate synergistic process to degradation atrazine:Efficiency,influencing factors,by-products removal and mechanism
9
作者 Qingkong Chen Jieyu Xia +3 位作者 Fengjun Liu Jianping Fan Peng Yan Mika Sillanpää 《Journal of Environmental Sciences》 2026年第1期166-177,共12页
This study developed a novel heterogeneous Vis-Photo+Fenton-like system by integrating visible-light-responsive Co_(3)O_(4)/TiO_(2) photocatalysis with peroxymonosulfate(PMS)activation for efficient atrazine(ATZ)degra... This study developed a novel heterogeneous Vis-Photo+Fenton-like system by integrating visible-light-responsive Co_(3)O_(4)/TiO_(2) photocatalysis with peroxymonosulfate(PMS)activation for efficient atrazine(ATZ)degradation.The synergistic process achieved complete ATZ removal within 60 min under near-neutral pH(6.9),outperform-ing individual Fenton-like(39%)and photocatalytic(24%)processes.Key factors influencing the degradation efficiency included light sources(UV>visible),pH(optimal at 6.9),catalyst dosage(0.01 g Co_(3)O_(4)/TiO_(2)),and PMS:ATZ molar ratio(1:2).The system exhibited a synergistic coefficient of 5.03(degradation)and 1.97(miner-alization),attributed to enhanced radical generation and accelerated Co^(3+)/Co^(2+)redox cycling through photoin-duced electron transfer.Intermediate analysis revealed dealkylation,dechlorination,and oxidation pathways,with reduced toxicity of by-products(e.g.,CEAT,CIAT)confirmed by ecotoxicity assessments.The mineralization efficiency(Vis-Photo+Fenton-like)reached 83.1%,significantly higher than that of standalone processes(Fenton-like:43.2%;photocatalysis:30.5%).The catalyst demonstrated excellent stability(nearly 90%recov-ery,<1μg/L Co leaching)and practical applicability.This study provides an efficient,sludge-free,and solar-compatible strategy for eliminating persistent herbicides in water treatment. 展开更多
关键词 Synergistic effect Sulfate radical FENTON-LIKE PHOTOCATALYSIS Visible light Atrazine(ATZ)
原文传递
A deep-junction single-photon detector with field polysilicon gate structure for increased photon detection efficiency and reduced dark count noise
10
作者 Zhentao Ni Dajing Bian +2 位作者 Haoxiang Jiang Xiaoming Huang Yue Xu 《Journal of Semiconductors》 2026年第1期65-71,共7页
A high-sensitivity,low-noise single photon avalanche diode(SPAD)detector was presented based on a 180 nm BCD process.The proposed device utilizes a p-implant layer/high-voltage n-well(HVNW)junction to form a deep aval... A high-sensitivity,low-noise single photon avalanche diode(SPAD)detector was presented based on a 180 nm BCD process.The proposed device utilizes a p-implant layer/high-voltage n-well(HVNW)junction to form a deep avalanche multiplication region for near-infrared(NIR)sensitivity enhancement.By optimizing the device size and electric field of the guard ring,the fill factor(FF)is significantly improved,further increasing photon detection efficiency(PDE).To solve the dark noise caused by the increasing active diameter,a field polysilicon gate structure connected to the p+anode was investigated,effectively suppressing dark count noise by 76.6%.It is experimentally shown that when the active diameter increases from 5 to 10μm,the FF is significantly improved from 20.7%to 39.1%,and thus the peak PDE also rises from 13.3%to 25.8%.At an excess bias voltage of 5 V,a NIR photon detection probability(PDP)of 6.8%at 905 nm,a dark count rate(DCR)of 2.12 cps/μm^(2),an afterpulsing probability(AP)of 1.2%,and a timing jitter of 216 ps are achieved,demonstrating excellent single photon detection performance. 展开更多
关键词 single-photon avalanche diode(SPAD) fill factor(FF) photon detection efficiency(PDE) dark count rate(DCR)
在线阅读 下载PDF
Contribution of ferroptosis and SLC7A11 to light-induced photoreceptor degeneration
11
作者 Xiaoxu Huang Yumeng Zhang +9 位作者 Yuxin Jiang Tong Li Shiqi Yang Yimin Wang Bo Yu Minwen Zhou Guanran Zhang Xiaohuan Zhao Junran Sun Xiaodong Sun 《Neural Regeneration Research》 2026年第1期406-416,共11页
Progressive photoreceptor cell death is one of the main pathological features of age-related macular degeneration and eventually leads to vision loss.Ferroptosis has been demonstrated to be associated with retinal deg... Progressive photoreceptor cell death is one of the main pathological features of age-related macular degeneration and eventually leads to vision loss.Ferroptosis has been demonstrated to be associated with retinal degenerative diseases.However,the molecular mechanisms underlying ferroptosis and photoreceptor cell death in age-related macular degeneration remain largely unexplored.Bioinformatics and biochemical analyses in this study revealed xC^(–),solute carrier family 7 member 11-regulated ferroptosis as the predominant pathological process of photoreceptor cell degeneration in a light-induced dry age-related macular degeneration mouse model.This process involves the nuclear factor-erythroid factor 2-related factor 2-solute carrier family 7 member 11-glutathione peroxidase 4 signaling pathway,through which cystine depletion,iron ion accumulation,and enhanced lipid peroxidation ultimately lead to photoreceptor cell death and subsequent visual function impairment.We demonstrated that solute carrier family 7 member 11 overexpression blocked this process by inhibiting oxidative stress in vitro and in vivo.Conversely,solute carrier family 7 member 11 knockdown or the solute carrier family 7 member 11 inhibitor sulfasalazine and ferroptosis-inducing agent erastin aggravated H_(2)O_(2)-induced ferroptosis of 661W cells.These findings indicate solute carrier family 7 member 11 may be a potential therapeutic target for patients with retinal degenerative diseases including age-related macular degeneration. 展开更多
关键词 age-related macular degeneration ferroptosis light exposure damage oxidative stress pathway PHOTORECEPTOR programmed cell death solute carrier family 7 member 11(SLC7A11)
暂未订购
A Cross-Band Quantum Light Source Based on Spontaneous Four-Wave Mixing in a Shallow-Ridge Silicon Waveguide
12
作者 Yijia Wang Qirui Ren +2 位作者 Zhanping Jin Yidong Huang Wei Zhang 《Chinese Physics Letters》 2026年第1期64-70,共7页
To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.T... To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks. 展开更多
关键词 photon pair generation shallow ridge silicon waveguide spontaneous four wave mixing optical fiber networks adjusting ridge widthenabling cross band quantum light source broadband photon pair generation waveguide dispersion
原文传递
Single-cell profiling reveals Müller glia coordinate retinal intercellular communication during light/dark adaptation via thyroid hormone signaling 被引量:2
13
作者 Min Wei Yanping Sun +10 位作者 Shouzhen Li Yunuo Chen Longfei Li Minghao Fang Ronghua Shi Dali Tong Jutao Chen Yuqian Ma Kun Qu Mei Zhang Tian Xue 《Protein & Cell》 SCIE CSCD 2023年第8期603-617,共15页
Light adaptation enables the vertebrate visual system to operate over a wide range of ambient illumination.Regulation of phototransduction in photoreceptors is considered a major mechanism underlying light adaptation.... Light adaptation enables the vertebrate visual system to operate over a wide range of ambient illumination.Regulation of phototransduction in photoreceptors is considered a major mechanism underlying light adaptation.However,various types of neurons and glial cells exist in the retina,and whether and how all retinal cells interact to adapt to light/dark conditions at the cellular and molecular levels requires systematic investigation.Therefore,we utilized single-cell RNA sequencing to dissect retinal cell-type-specific transcriptomes during light/dark adaptation in mice.The results demonstrated that,in addition to photoreceptors,other retinal cell types also showed dynamic molecular changes and specifically enriched signaling pathways under light/dark adaptation.Importantly,Müller glial cells(MGs)were identified as hub cells for intercellular interactions,displaying complex cell‒cell communication with other retinal cells.Furthermore,light increased the transcription of the deiodinase Dio2 in MGs,which converted thyroxine(T4)to active triiodothyronine(T3).Subsequently,light increased T3 levels and regulated mitochondrial respiration in retinal cells in response to light conditions.As cones specifically express the thyroid hormone receptor Thrb,they responded to the increase in T3 by adjusting light responsiveness.Loss of the expression of Dio2 specifically in MGs decreased the light responsive ability of cones.These results suggest that retinal cells display global transcriptional changes under light/dark adaptation and that MGs coordinate intercellular communication during light/dark adaptation via thyroid hormone signaling. 展开更多
关键词 single cell Müller glial cells intercellular communication light/dark adaptation thyroid hormone signaling
暂未订购
Effects of short light/dark cycles on photosynthetic pathway switching and growth of medicinal Dendrobium officinale in aeroponic cultivation 被引量:2
14
作者 Yongsan Cheng Dongxian He +2 位作者 Jie He Genhua Niu Fang Ji 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2019年第5期38-43,共6页
Dendrobium officinale has high medicinal value but grows slowly in natural environment due to its special CAM photosynthetic pathway.In this study,D.officinale were grown aeroponically with light/dark cycles of 12 h/1... Dendrobium officinale has high medicinal value but grows slowly in natural environment due to its special CAM photosynthetic pathway.In this study,D.officinale were grown aeroponically with light/dark cycles of 12 h/12 h,4 h/4 h,and 2 h/2 h for 150 d.The photosynthetic electron transfer characteristics,photosynthetic CO_(2) fixation pathways,and accumulations of biomass and soluble polysaccharides in D.officinale leaves were studied.The results showed that the photosynthetic apparatus states of D.officinale in aeroponic cultivation under short light/dark cycles of 4 h/4 h and 2 h/2 h were better than that under 12 h/12 h.The dark net CO_(2) exchange percentages of D.officinale were negative in short light/dark cycles of 4 h/4 h and 2 h/2 h,and the daily net CO_(2) exchange amount and dry/fresh weight increases were doubled compared with those in 12 h/12 h light/dark cycle.High soluble polysaccharides content and the soluble polysaccharides yield of D.officinale were obtained in the shorter light/dark cycle of 2 h/2 h.Therefore,the photosynthetic pathway of D.officinale could be switched from CAM to C3 by short light/dark cycles of 4 h/4 h and 2 h/2 h,and its higher biomass accumulation and soluble polysaccharides yield could be obtained by the shorter light/dark cycle of 2 h/2 h in aeroponic cultivation. 展开更多
关键词 dark net CO_(2)exchange percentage photosynthetic pathway short light/dark cycle soluble polysaccharides
原文传递
Extent of mismatch between the period of circadian clocks and light/dark cycles determines time-to-emergence in fruit flies 被引量:1
15
作者 Pankaj Yadav Deepak Choudhury Madhumala K. Sadanandappa Vijay Kumar Sharma 《Insect Science》 SCIE CAS CSCD 2015年第4期569-577,共9页
Circadian clocks time developmental stages of fruit flies Drosophila melanogaster, while light/dark (LD) cycles delimit emergence of adults, conceding only during the "allowed gate." Previous studies have revealed... Circadian clocks time developmental stages of fruit flies Drosophila melanogaster, while light/dark (LD) cycles delimit emergence of adults, conceding only during the "allowed gate." Previous studies have revealed that time-to-emergence can be altered by mutations in the core clock gene period (per), or by altering the length of LD cycles. Since this evidence came from studies on genetically manipulated flies, or on flies maintained under LD cycles with limited range of periods, inferences that can be drawn are limited. Moreover, the extent of shortening or lengthening of time-to-emergence re- mains yet unknown. In order to pursue this further, we assayed time-to-emergence of D. rnelanogaster under 12 different LD cycles as well as in constant light (LL) and constant dark conditions (DD). Time-to-emergence in flies occurred earlier under LL than in LD cycles and DD. Among the LD cycles, time-to-emergence occurred earlier under T4-T8, followed by T36-T48, and then T12-T32, suggesting that egg-to-emergence duration in flies becomes shorter when the length of LD cycles deviates from 24 h, bearing a strong positive and a marginally negative correlation with day length, for values shorter and longer than 24 h, respectively. These results suggest that the extent of mismatch between the period of circadian clocks and environmental cycles determines the time-to-emergence in Drosophila. 展开更多
关键词 CIRCADIAN Drosophila light/dark regimes PERIOD time-to-emergence
原文传递
基于改进EnlightenGAN和YOLOv5s的夜间车辆目标检测
16
作者 安浩铭 陈松 +1 位作者 李龙 温宇鑫 《自动化与仪表》 2026年第1期56-62,67,共8页
针对夜间存在低照度、辉光、噪点等异常光照场景,降低了图像质量,影响车辆目标检测精度。该研究结合基于Retinex的辉光消除方法和自适应滤波改进EnlightenGAN网络,增强夜间异常光照图像的质量,并将坐标注意力机制(CA)、加权双向特征金字... 针对夜间存在低照度、辉光、噪点等异常光照场景,降低了图像质量,影响车辆目标检测精度。该研究结合基于Retinex的辉光消除方法和自适应滤波改进EnlightenGAN网络,增强夜间异常光照图像的质量,并将坐标注意力机制(CA)、加权双向特征金字塔(BiFPN)和小目标检测头引入YOLOv5s,构建了YOLOv5s-CBH网络,实现夜间车辆目标的检测。通过构建夜间车辆数据集并进行对比试验,对所提出方法的有效性进行验证。结果表明,与现有算法相比,改进EnlightenGAN网络有效抑制了辉光并提高信噪比,获得了良好的视觉效果并协调整体纹理和细节。通过将增强后的图像输入YOLOv5s-CBH进行对比试验,结果表明YOLOv5s-CBH的精确度、召回率和m AP得到了提升,精确度和召回率略低于x网络,但mAP和网络大小得到了优化。研究结果表明,该文所提出的模型可以有效提高夜间异常光照下车辆的目标检测精度,为复杂环境下辅助驾驶系统的智能检测和预警提供了参考。 展开更多
关键词 夜间异常光照 EnlightenGAN YOLOv5s 图像增强 车辆目标检测
在线阅读 下载PDF
A Topological Magueijo-Smolin Varying Speed of Light Theory, the Accelerated Cosmic Expansion and the Dark Energy of Pure Gravity 被引量:8
17
作者 Mohamed Salah El Naschie Leila Marek-Crnjac +1 位作者 Mohamed Atef Helal Ji-Huan He 《Applied Mathematics》 2014年第12期1780-1790,共11页
The paper presents a detailed analysis of ordinary and dark energy density of the cosmos based on two different but complimentary theories. First, and starting from the concept of the speed of light being an average o... The paper presents a detailed analysis of ordinary and dark energy density of the cosmos based on two different but complimentary theories. First, and starting from the concept of the speed of light being an average over multi-fractals, we use Magueijo-Smolin’s ingenious revision of Einstein’s special relativity famous formula E = mc2 to a doubly special formula which includes the Planck energy as invariant to derive the ordinary energy density E(O) = mc2/22 and the dark energy density E(D) = mc2(21/22) wheremis the mass andcis the speed of light. Second we use the topological theory of pure gravity to reach the same result thus confirming the correctness of the theory of varying speed of light as well as the COBE, WMAP and Type 1a supernova cosmological measurements. 展开更多
关键词 dark ENERGY QUANTUM GRAVITY VARYING Speed of light THEORY ENERGY of QUANTUM Wave QUANTUM Non-Demolition
在线阅读 下载PDF
A modified light-dark box test for the common marmoset 被引量:1
18
作者 Yiwen Wang Qin Fang Neng Gong 《Neuroscience Bulletin》 SCIE CAS CSCD 2014年第3期394-400,共7页
The common marmoset (Callithrix jacchus) has attracted extensive attention for use as a non-human primate model in biomedical research, especially in the study of neuropsychiatric disorders. However, behavioral test... The common marmoset (Callithrix jacchus) has attracted extensive attention for use as a non-human primate model in biomedical research, especially in the study of neuropsychiatric disorders. However, behavioral test methods are still limited in the field of marmoset research. The light-dark box is widely used for the evaluation of anxiety in rodents, but little is known about light-dark preference in marmosets. Here, we modified the light-dark test to study this behavior. The modified apparatus consisted of three compartments: one transparent open area and two closed opaque compartments. The closed compartments could be dark or light. We found that both adult and young marmosets liked to explore the open area, but the young animals showed more interest than adults. Furthermore, when one of the closed compartments was light and the other dark, the adult marmosets showed a preference for the dark compartment, but the young animals had no preference. These results suggest that the exploratory behavior and the light-dark preference in marmosets are age-dependent. Our study provides a new method to study exploration, anxiety, and fear in marmosets. 展开更多
关键词 MARMOSET behavioral test light-dark box EXPLORATION ANXIETY
原文传递
基于RF-Light GBM的分组密码算法识别方案
19
作者 董秀则 杨鸿刚 +1 位作者 胡一凡 于庚辰 《北京电子科技学院学报》 2025年第2期1-10,共10页
密码算法的识别在密码分析领域中具有重要意义。目前主流分组密码算法识别方案中密文特征提取普遍基于随机性检测标准。为解决短样本识别需求以及进一步提高识别准确率,本研究提出了一种基于RF-Light GBM的分组密码体制识别方案。首先通... 密码算法的识别在密码分析领域中具有重要意义。目前主流分组密码算法识别方案中密文特征提取普遍基于随机性检测标准。为解决短样本识别需求以及进一步提高识别准确率,本研究提出了一种基于RF-Light GBM的分组密码体制识别方案。首先通过GM/T 0005-2021随机性检测标准提取密文特征,其次利用随机森林算法对高维的数据进行重要性排序和筛选,然后利用特征向量训练Light GBM算法模型构建密码算法识别分类器进行识别。实现了短样本环境下高效识别未知密文的识别需求。在两两识别实验中,与现有研究相比本方案准确率整体提升约12%;多分类实验显示准确率均在73%以上,验证了本方案在分组密码算法识别中的有效性和优势,为未来在更复杂的加密模式下进行密码算法识别提供了参考。 展开更多
关键词 分组密码 机器学习 随机性检测 密码算法识别 light GBM
在线阅读 下载PDF
The Light-Dark Dual Universe for the Big Bang and Dark Energy 被引量:2
20
作者 Ding-Yu Chung Volodymyr Krasnoholovets 《Journal of Modern Physics》 2013年第7期77-84,共8页
In the proposed light-dark dual universe, the light universe is the observable universe with light and kinetic energy that fueled the Big Bang, and the dark universe without light and kinetic energy has been observed ... In the proposed light-dark dual universe, the light universe is the observable universe with light and kinetic energy that fueled the Big Bang, and the dark universe without light and kinetic energy has been observed as dark energy since about 9 billion years after the Big Bang. The light-dark dual universe started from the zero-energy universe through the four-stage cyclic transformation. Emerging from the zero-energy universe, the four-stage transformation consists of the 11D (dimensional) positive-negative energy dual membrane universe, the 10D positive-negative energy dual string universe, the 10D positive-negative energy dual particle universe, and the 4D (light)-variable D (dark) positive-negative energy dual particle asymmetrical universe. The transformation can then be reversed back to the zero-energy universe through the reverse four-stage transformation. The light universe is an observable four-dimensional universe started with the inflation and the Big Bang, and the dark universe is a variable dimensional universe from 10D to 4D. The dark universe could be observed as dark energy only when the dark universe turned into a four-dimensional universe. The four-stage transformation explains the four force fields in our universe. The theoretical calculated percentages of dark energy, dark matter, and baryonic matter are 72.8. 22.7, and 4.53, respectively, in nearly complete agreement with observed 72.8, 22.7, and 4.56, respectively. According to the calculation, dark energy started in 4.47 billion years ago in agreement with the observed 4.71 ± 0.98 billion years ago. The zero-energy cyclic universe is based on the space-object structures. 展开更多
关键词 Cosmology light UNIVERSE dark UNIVERSE DUAL UNIVERSE Big Bang Inflation Zero-Energy Cyclic UNIVERSE dark ENERGY dark MATTER Baryonic MATTER Force Fields
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部