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- 2018
- LED stage lighting
- CRI
- RGBW four-color mixing model
- the blackbody locus fitting
- Optoelectronic Information Science and Engineering
- Communication University of China
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Dynamic Structural Color from Wrinkled Thin Films
摘要： Structural color caused by thin-film interference is widespread and simple in nature. Many researchers have already showed the reversible color change of structural color system, but it is difficult to regulate dynamically with tunable intensity and viewable angle. Herein, a dynamic structural color platform is reported by combining spontaneous thin film interference and wrinkling phenomenon in nature. This robust yet low cost strategy enables large-scale and spatially arbitrary preparation of a uniform structural color surface through the whole visible spectral range. Furthermore, the prepared isotropic and anisotropic structural colors on disordered and ordered wrinkled thin films (WTFs) exhibit different optical properties that can be precisely and reversibly regulated by ultraviolet (UV) light and near-infrared (NIR) light irradiation. This exquisite and tunable structural color platform may find applications in information storage, smart display, anticounterfeiting and encryption.
关键词： dynamic structural color,tunable viewable angle,thin film,reversible wrinkle
更新于2025-09-23 15:19:57
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A sequence-specific plasmonic loop-mediated isothermal amplification (LAMP) assay with orthogonal color readouts enabled by CRISPR Cas12a
摘要： Herein, we introduce a sequence-specific plasmonic LAMP assay with dual, complementary color readouts enabled by CRISPR Cas12a. Using this assay, any double-stranded LAMP amplicon containing a 5’TTN PAM sequence can be recognized by Cas12a through a specific CRISPR RNA. The signal transduction is achieved using two orthogonal plasmonic systems mediated by Cas12a.
关键词： orthogonal color readouts,sequence-specific detection,plasmonic LAMP assay,CRISPR Cas12a
更新于2025-09-23 15:19:57
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Analysis of two-color laser-induced electron emission from a biased metal surface using an exact quantum mechanical solution
摘要： Photoelectron emission from solids, as driven by high-intensity lasers, offers a platform for the coherent control of electron motion on ultrashort spatiotemporal scales. By solving the time-dependent Schr?dinger equation, we present an exact analytical solution for the nonlinear ultrafast electron emission from a dc-biased metal surface illuminated by two-color laser fields. We systematically examine the combined effects of a dc electric field and two-color laser fields. In addition to the remarkable tunability of electron emission processes due to interference from two-color laser fields, we find that a strong dc electric field not only opens up more tunneling emission channels, but also introduces intense modulation to the emission current. We find surprising results that strong current modulation (with respect to the phase difference of the two-color lasers) persists (>70%), even with a large dc bias (i.e., ratio of the electric fields for dc : fundamental laser : second-harmonic laser ～= 1 : 0.5 : 0.07). In the meantime, the average emission current level increases by about three orders of magnitude relative to the case of zero dc bias. Application of our model to time-resolved photoelectron spectroscopy is exemplified and shows that the dynamics of the n-photon excited states depends strongly on the applied dc field. Our study suggests a practical way to maintain a strong modulation to high current photoemission, by the addition of a large dc bias for two-color laser-induced electron emission.
关键词： dc electric field,two-color laser fields,ultrafast electron emission,photoelectron emission,time-dependent Schr?dinger equation
更新于2025-09-23 15:19:57
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Modifying twisted nematic LCD screens to create dichromatic visual stimuli with LEDs
摘要： 1. The use of computers to create and display animations/videos in the study of visually-guided behaviors has been instrumental in understanding sensory mechanisms underlying complex traits. Using computer displays scientists are able to create a wide array of colors using three differently colored lights (Red, Green, Blue: RGB). While it is possible to generate scenes with RGB displays that mimic animals’ color perceptual experience, this can be problematic because it requires knowledge of the spectral absorbance of the animals’ photoreceptor classes, which are often unknown and are difficult to obtain. Even then, stimuli are limited to the central part of the visible spectrum (e.g., ultraviolet (UV) stimuli are not possible). 2. We present a cost-effective way of modifying a twisted nematic LCD screen that utilizes colored LEDs, that allows measuring animals’ sensitivity to, and discrimination between, wavelengths of light. It has the benefit of not requiring a-priori knowledge of animals’ photoreceptor classes. An LCD screen can be modified by removing the screen’s back polarizer (behind the liquid crystal layer) and backlighting the screen with LEDs of two different colors. One of the LED colors transmits through a polarizer with a transmission axis parallel to the screen’s front polarizer, and other LED color transmits through a polarizer orthogonal to the first. 3. To test color discrimination one can create a dichromatic stimulus in which both LED colors are ‘ON’ and the current fithrough one LED color is decreased, while the other is constant, which generated a maximum intensity contrast of 1.84 log units in our setup. To test color sensitivity one can create a monochromatic stimulus in which only one LED color is ‘ON’, which generates a contrast similar to the dichromatic stimulus. This technique overcomes many of the limitations of RGB-based LCD screens in a cost-effective way, and allows more accurate testing of the role of color in visually-guided behaviors. Besides the questions in vision research this setup can answer, it can also be used as an outreach tool in classrooms where children can learn about light, color, polarization, and technology.
关键词： twisted nematic LCD screen,spectral sensitivity,polarization,visually-guided behavior,color vision,spectrometer,LED
更新于2025-09-23 15:19:57
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Impacts of colored light-emitting diode illumination on the growth performance and fecal microbiota in goose
摘要： Besides on the reproductive performance, the light also has an important effect on the growth in birds. In the present study, we for the first time investigated effects of colored light-emitting diodes (LED) on both growth performance and fecal microbiota in meat geese. We randomly selected a total of 120 geese at birth (0-day), divided them into 3 groups evenly (i.e., 40 geese each group), and then reared them under 3 colored light-emitting diodes (i.e., blue, red, and white) with the same photoperiod for 9 wk, respectively. We collected fecal samples at the experimental day 35 and 63, respectively. We observed that geese in blue light had higher body weight than those in red and white lights at the early stage of the experiment but showed lower body weight at the late stage, particularly at day 63 (P , 0.05). Interestingly, we found that the relative abundances of 3 dominant bacteria phyla, Firmicutes, Proteobacteria, and Cyanobacteria, were comparable among 3 groups at day 35, while at day 63, the blue light group had the significantly (P , 0.05) lowest and highest abundance for Firmicutes and Proteobacteria, respectively. Functional enrichment analyses revealed that the fecal microbiota in the red light group was mainly involved in metabolism at day 35, whereas at day 63, the fecal microbiota were engaged into membrane transportation and transcription. In contrast, the blue light group had more enriched pathways relevant with membrane transportation at day 63 than day 35 and had several pathways involved in metabolism at day 63 as well. Collectively, our results revealed that the light with different colors affects the growth performance of geese via the gut microbiota, which in turn influences the digestion and absorption of geese.
关键词： growth performance,light color,meat goose,fecal microbiota
更新于2025-09-23 15:19:57
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Giant Isolated Attosecond Pulses from Two-Color Laser-Plasma Interactions
摘要： A new regime in the interaction of a two-color (ω; 2ω) laser with a nanometer-scale foil is identified, resulting in the emission of extremely intense, isolated attosecond pulses—even in the case of multicycle lasers. For foils irradiated by lasers exceeding the blow-out field strength (i.e., capable of fully separating electrons from the ion background), the addition of a second harmonic field results in the stabilization of the foil up to the blow-out intensity. This is then followed by a sharp transition to transparency that essentially occurs in a single optical cycle. During the transition cycle, a dense, nanometer-scale electron bunch is accelerated to relativistic velocities and emits a single, strong attosecond pulse with a peak intensity approaching that of the laser field.
关键词： two-color laser,laser-plasma interactions,attosecond pulses,coherent synchrotron emission
更新于2025-09-23 15:19:57
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Tuning the Emission Colors of Self-Assembled Quantum Dot Monolayers via One-Step Heat Treatment for Display Applications
摘要： Homogeneously self-assembled colloidal semiconductor quantum dot monolayers (QD-SAMs) over large areas are promising materials for thin film optoelectronic device applications, especially for display. Although tuning of emission colors from QDs is generally achieved during wet chemical synthesis and before monolayer formation, we propose in this study a simple and effective method to adjust emission colors after the formation of QD-SAMs by a simple one-step heat treatment. CdSe-based core/shell or core/double shell structured QDs (CdSe/ZnS, CdSe/CdZnS, and CdSe/CdS/ZnS) covered with an optimal set of hydrophobic ligands can form homogeneous and stable QD-SAMs at the air-water interface. The QD-SAMs are subsequently transferred onto hydrophobized glass substrates by the Langmuir-Schaefer (LS) method and thermally treated in air. We found a blueshift of more than 35 nm for the emission wavelength (red to green) by a thermal treatment at 280 °C for 150 min with CdSe/ZnS QD-SAMs. The color can be adjusted by changing the heating temperature and the treatment time. The wavelength shift is in the order of CdSe/ZnS(4L) > CdSe/ZnS(6L) = (CdSe/CdZnS) > (CdSe/CdS/ZnS). The energy dispersive X-ray (EDX) microanalysis of a single QD reveals that the blueshift is mainly caused by atomic diffusion-induced alloying of core/shell type QDs. The main problem of this method is the decreasing emission intensity caused by oxidation during the heat treatment; however, this problem can be solved by use of a SiO2 protective coating on the QD-SAMs. We believe that this simple technique is useful for manufacturing RGB-colored ultrathin QD-SAM films for QDs displays such as QD film display, QD color-filter display, and QD light emitting diode.
关键词： QD Display,Quantum dots,Color tuning,Self-assembled monolayer,atomic diffusion-induced alloying,Thermal treatment
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Optimization of the Light Trapping Nano Structures in CdTe Thin Film Solar Cells
摘要： Traditional sparse image models treat color image pixel as a scalar, which represents color channels separately or concatenate color channels as a monochrome image. In this paper, we propose a vector sparse representation model for color images using quaternion matrix analysis. As a new tool for color image representation, its potential applications in several image-processing tasks are presented, including color image reconstruction, denoising, inpainting, and super-resolution. The proposed model represents the color image as a quaternion matrix, where a quaternion-based dictionary learning algorithm is presented using the K-quaternion singular value decomposition (QSVD) (generalized K-means clustering for QSVD) method. It conducts the sparse basis selection in quaternion space, which uniformly transforms the channel images to an orthogonal color space. In this new color space, it is significant that the inherent color structures can be completely preserved during vector reconstruction. Moreover, the proposed sparse model is more efficient comparing with the current sparse models for image restoration tasks due to lower redundancy between the atoms of different color channels. The experimental results demonstrate that the proposed sparse image model avoids the hue bias issue successfully and shows its potential as a general and powerful tool in color image analysis and processing domain.
关键词： Vector sparse representation,K-QSVD,dictionary learning,quaternion matrix analysis,image restoration,color image
更新于2025-09-23 15:19:57
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Tuning the Color Palette of Semi-Transparent Solar Cells via Lateral ??-Extension of Polycyclic Heteroaromatics of Donora??Acceptor Dyes
摘要： Durable solar cells with tunable color and diaphaneity are very promising for building integrated photovoltaic applications. In this paper we employ donor–acceptor organic dyes U3, U4, U5, and R6 featured by polycyclic heteroaromatics 6,12-dihydroindeno[1,2-b]indeno[2',1':4,5]thieno[2,3-d]thiophene (IT2), 7,15-dihydrobenzo[6',7']indeno[2',1':4,5]thieno[3,2-b]benzo[6,7]indeno[2,1-d]thiophene (BIT2), 7,15-dihydrophenaleno[1,2-b]phenaleno[2',1':4,5]thieno[2,3-d]thiophene (PT2), and 9,19-dihydrobenzo[1',10']phenanthro[3',4':4,5]thieno[3,2-b]benzo[1,10]phenanthro[3,4-d]thiophene (BPT2) to fabricate semi-transparent dye-sensitized solar cells (DSSCs). The U3, U4, U5, and R6 based cells are goldenrod, crimson, red, and sapphire blue, with power conversion efficiencies of 3.5%, 8.2%, 7.6, and 10.1% at the AM1.5G conditions. Density functional theory calculation and voltammetric measurement reveal that lateral π-extension of polycyclic heteroaromatic brings forth a downward displacement of lowest unoccupied molecular orbital, affording a high molar extinction coefficient, low-energy gap blue dye. Femtosecond fluorescence decay measurements of dyed titania and alumina films unravel the electron injection yields of photo-excited dye molecules, which are well correlated with the maximal values of external quantum efficiencies of DSSCs. After 1,000 h full sunlight soaking at 60 oC, the red and blue DSSCs exhibit stable photocurrents, owing to the strong bonding and photochemical stability of dye molecules adsorbed on the surface of titania as well as the retention of close-to-unity electron collection yield.
关键词： electron injection,durability,tunable color,semi-transparent solar cell,lateral π-extension,photosensitizer
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Frequency Reconfigurable Slot Antenna Backed by the Substrate Integrated Waveguide Cavity for 5G Applications
摘要： In this paper, a novel near-lossless color ?lter array (CFA) image compression algorithm based on JPEG-LS is proposed for VLSI implementation. It consists of a pixel restoration, a prediction, a run mode, and entropy coding modules. According to the information of the previous research, a context table and row memory consumed more than 81% hardware cost in a JPEG-LS encoder design. Hence, in this paper, a novel context-free and near-lossless image compression algorithm is presented. Since removing the context model causes decreasing of the compression performance, a novel prediction, run mode, and modi?ed Golomb–Rice coding techniques were used to improve the compression ef?ciency. The VLSI architecture of the proposed image compressor consists of a register bank, a pixel restoration module, a predictor, a run mode module, and an entropy encoder. A pipeline technique was used to improve the performance of this. It contains only 10.9k gate count, and the core area is 30 625 μm2, synthesized by using a 90-nm CMOS process. Compared with the previous JPEG-LS designs, this paper reduces the gate counts by 44.1% and 41.7%, respectively, for ?ve standard and eight endoscopy testing images in CFA format. It also improves the average PSNR values by 0.96 and 0.43 dB, respectively, for the same test images.
关键词： JPEG-LS,Color ?lter array,VLSI,context-free,wireless capsule endoscopy,Golomb-Rice coding,near-lossless,run mode
更新于2025-09-23 15:19:57