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Overhead supplemental far-red light stimulates tomato growth under intra-canopy lighting with LEDs
摘要： Far-red (FR) light regulates phytochrome-mediated morphological and physiological plant responses. This study aims to investigate how greenhouse tomato morphology and production response to different durations of FR light during daytime and at the end of day (EOD). High-wire tomato plants were grown under intra-canopy lighting consisting of red (peak wavelength at 640 nm) and blue (peak wavelength at 450 nm) light-emitting diodes (LEDs) with photosynthetic photon flux density (PPFD) of 144 μmol m–2 s–1 at 10 cm away from the lamps, and combined with overhead supplemental FR light (peak wavelength at 735 nm) with PPFD of 43 μmol m–2 s–1 at 20 cm below the lamps. Plants were exposed to three durations of FR supplemental lighting including: 06:00–18:00 (FR12), 18:00–19:30 (EOD-FR1.5), 18:00–18:30 (EOD-FR0.5), and control that without supplemental FR light. The results showed that supplemental FR light significantly stimulated stem elongation thereby resulting in longer plants compared with the control. Moreover, FR light altered leaf morphology toward higher leaf length/width ratio and larger leaf area. The altered plant architecture in FR supplemented plants led to a more homogeneous light distribution inside the canopy. Total plant biomass was increased by 9–16% under supplemental FR light in comparison with control, which led to 7–12% increase in ripe fruit yield. Soluble sugar content of the ripe tomato fruit was slightly decreased by longer exposure of the plants to FR light. Dry matter partitioning to different plant organs were not substantially affected by the FR light treatments. No significant differences were observed among the three FR light treatments in plant morphology as well as yield and biomass production. We conclude that under intra-canopy lighting, overhead supplemental FR light stimulates tomato growth and production. And supplementary of EOD-FR0.5 is more favorable, as it consumes less electricity but induces similar effects on plant morphology and yield.
关键词： intro-canopy lighting,morphology,far-red light,LEDs,yield,Solanum lycopersicum
更新于2025-09-12 10:27:22
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Influence of the acceptor crystallinity on the open-circuit voltage in PTB7-Th: ITIC organic solar cells
摘要： The influence of the solution property on both the morphology and the device performance is discussed through various investigation methods based on ITO/ZnO/PTB7-Th: ITIC/MOO3/Ag Organic Solar Cells (OSCs). It is found that the solution component plays an important role in the morphology and the crystallinity of the active layers as confirmed by atomic force microscope (AFM) and grazing incident wide-angle X-ray scattering (GIWAXS), resulting in obviously difference in the open-circuit voltage (VOC) of the devices. The crystallinity of ITIC acceptor in the active layer is further found to correlate with the energy of charge transfer states (CTS) of the devices according to the Electroluminescence (EL) Spectrometry measurements. The CTS energy shift caused by the crystallinity variation is directly related to the enhanced VOC in this study.
关键词： open-circuit voltage,morphology,charge transfer states,crystallinity,organic solar cells
更新于2025-09-12 10:27:22
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Fast smoothing on diamond surface by inductively coupled plasma reactive ion etching
摘要： The synergetic effects of surface smoothing exhibited during the inductively coupled plasma reactive ion etching (ICP-RIE) of free-standing polycrystalline diamonds (PCDs) were investigated. Changing the assistive gas types generated variable surface oxidation states and chemical environments that resulted in different etching rates and surface morphologies. The main reaction bond mechanism (C–O) during ICP-RIE and the ratio of C–O–C/O–C=O associated with the existence of a uniform smooth surface with root mean square (RMS) roughness of 2.36 nm were observed. An optimal process for PCD smoothing at high etching rate (4.6 lm/min) was achieved as follows: 10% gas additions of CHF3 in O2 plasma at radio frequency power of 400 W. The further etched ultra-smooth surface with RMS roughness <0.5 nm at etching rate of 0.23 lm/min that being produced by transferring this optimum recipe on single crystal diamonds with surface patterns confirmed the effectiveness of the fast smoothing approach and its feasibility for diamond surface patterning.
关键词： surface smoothing,diamond,etching rate,ICP-RIE,surface morphology
更新于2025-09-12 10:27:22
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Synthesis of BiOCl: Eu3+ Microarchitectures and their WLED’s, Fingerprint Detection and Anticounterfeiting Applications
摘要： BiOCl: Eu3+(1-9mol %) microarchitectures were synthesized by the solution combustion method by employing Barbituric acid as fuel. The crystal structure, morphologies and luminescence properties of Eu3+ doped BiOCl have been systematically investigated by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) and spectroscopy respectively. The prime objective of the current effort was first to fabricate highly luminescent nanophosphor for revelation of latent fingerprints, lips prints including infiltrating and non-filtrating surfaces and also to develop luminescent ink for anticounterfeiting applications. Presently the fingerprints developed by using conventional powders have several disadvantages including low sensitivity, high background hindrance, complicated procedure and high toxicity. To encounter this challenge, we explored the optimized BiOCl:Eu3+(3mol %) nanophosphor for detection of latent fingerprints and luminescent anti-counterfeiting ink. The morphology of the phosphor was tuned by adjusting the concentration of fuel. Photoluminescence studies of BiOCl:Eu3+(1-9mol %) exhibited the peaks 5D0 → 7FJ (J = 0, 1, 2, 3, 4) transitions. The CIE and CCT characteristics specify that the synthesized nanophosphor might be immensely show potential red factor for promising applications in WLED’s. The BiOCl: Eu3+ (1-9 mol %) nanopowder also showed clear ridge patterns of level I and level II and further showed sharp image of label when observed in the UV light. The results indicated that the present phosphor could be used in both forensic as well as in anti counterfeiting applications.
关键词： Barbituric acid,BiOCl,morphology,luminescence,photoluminescence,nanophosphor,Eu3+
更新于2025-09-12 10:27:22
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On the study of microstructure of annealed C+and H2+ Co_implanted 6H-SiC
摘要： The microstructure of annealed single crystal 6H-SiC implanted with C+ and H2+ ions were characterized by glancing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After annealing, cracks were observed to form in the surface of C+ ions implanted sample. However, blisters as circular clusters were observed in the surface of the H2+ ions implanted and annealed sample. Compared with the samples implanted with only single type of ions, both cracks and blisters with different morphologies were found to appear in the surface of C+ and H2+ ions co-implanted sample. The morphology and distribution of blisters and exfoliations in the C+ and H2+ co-implanted samples were more irregular and inhomogeneous than those in the H2+ ions implanted sample, which can be attributed to the randomly distributed columnar crystals formed during the annealing process. The grain boundaries of these columnar crystals could be used as migration channels for hydrogen, which influence the size evolution of blisters and exfoliations in the sample surface during annealing process.
关键词： Microstructure,SiC,Annealing,Surface morphology,Ion irradiation
更新于2025-09-12 10:27:22
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Surface integrity of water jet guided laser machining of CFRP
摘要： Carbon fiber reinforced plastics (CFRP) is now applied widely in various industries because of its excellent properties. Although conventional processing methods, such as milling and abrasive water jet, are the dominating techniques used, laser cutting of CFRP is still attractive owing to the wear-free, contactless and flexible processing. However, the anisotropic material properties of CFRP, the issues related to the heat affected zone (HAZ) and delamination during laser processing, are major obstacles in its application. In order to reduce the heat damage caused by laser, a compound machining method, water jet guided laser technique, was adopted to cut CFRP in this paper. In addition, we make a comparative investigation for conventional laser beam machining and water jet guided laser machining with an identical material. The difference of kerf geometry, HAZ, surface morphology and efficiency was discussed within this research. The experiments showed that the HAZ of water jet guided laser is smaller than conventional laser beam machining, but much less efficient. Water jet guided laser technique is a potential processing method for CFRP if the efficiency is improved.
关键词： CFRP,surface morphology,water jet guided laser,HAZ
更新于2025-09-12 10:27:22
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Influence of welding angle on the weld morphology and porosity in laser-arc hybrid welding of AA2219 aluminum alloy
摘要： The influence of welding angle on weld morphologies and porosity characteristics was studied in laser-arc hybrid welding of AA2219 aluminum (Al) alloy. The upward sloping and vertical weld (USVW) was performed better than the downward sloping and vertical weld (DSVW). The high-speed camera was used to observe the welding process. It is found that the welding process becomes stable when the transitional position of the droplet was 2 mm away from the keyhole. By analyzing the force act on keyhole and characteristics of the pool, it is found that the weld morphologies and porosity characteristics were associated with gravity-laser angle (β), which affects the keyhole stability and characteristics of the pool. The results showed that the flow velocity was accelerated when the β increased, which was a benefit for decreasing porosity. This is because the gravity in the direction of the welding accelerates the pool flow. Due to the increasing of the β, the static pressure and the vapor pressure in the keyhole were increased, which improved the stability of the keyhole and decreased the porosity.
关键词： Keyhole,Weld morphology,Porosity,Aluminum alloy,Laser-arc hybrid welding
更新于2025-09-12 10:27:22
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Creation of heterogeneous metal-ceramic structures based on Ti, Ni and WC, B4C by the combined method of laser cladding and cold gas-dynamic spraying
摘要： The paper pioneers the complex experimental investigation of the metal-ceramic coating made by the additive technologies, the combination of the cold gas-dynamic spraying (CS) and following layered laser processing. The coating is made of ceramic powders WC and В4С, the concentration in the initial mixture of 10-70 wt.%, and metal powders based on Ti+Al, the ratio 94:6 wt.%, and Ni. The result is the strategy of the production of the heterogeneous material without pores and cracks by the consequent deposition of the powder by the CS method followed by the laser action; the thickness of the coating is 4 mm.
关键词： laser action,microstructure,morphology,coating,microhardness,cold spraying
更新于2025-09-12 10:27:22
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High detectivity organic photodetectors in the visible light wavelength with ternary bulk heterojunction
摘要： In this work, we report an ternary bulk heterojunction (t-BHJ) organic photodetectors (OPDs) based on P3HT, PTB7 and PC61BM. The effects of PTB7 added to P3HT:PC61BM on the optical and electrical properties of OPDs were investigated. It is found that when the mass ratio of P3HT:PTB7:PC61BM is 8:2:10, the response spectrum of the active layer is extended to 780 nm, The responsivity (R) and external quantum efficiency (EQE) of the OPDs are reached 178, 291, 241 mA/W and 35%, 68%, 65%, under 630, 530, and 460 nm illumination and ?1 V bias, respectively, and the detectivity (D*) reached 1012 Jones. The results show that the addition of PTB7 with appropriate mass ratio can increases the exciton generation and dissociation probability in P3HT:PC61BM, which increases the photocurrent of the device. In addition, the addition of PTB7 promotes the crystallization of the film, reduces the density of trap defects in the film, and reduces the dark current of the device.
关键词： Microscopic morphology,Organic photodetectors,Ternary bulk heterojunction,Exciton dissociation
更新于2025-09-12 10:27:22
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Effect of Laser Processing Parameters on Surface Texture of Ti6Al4V Alloy
摘要： Surface micro-machining was performed on Ti6Al4V alloy sample by nanosecond laser. The micro-morphology, the depth of texture and the chemical composition of melt deposits were analyzed through different techniques including Ultra-Depth Microscopy, SEM and EDS. The single factor method was applied to investigate the influence of different laser parameters on the depth of texture and micro-morphology. The result showed that the depth of texture increased first and decreased with the increase of average power (11-20.9W), the texture depth decreases sharply when the scanning speed increased from 10mm/s to 40mm/s, and the repetition frequency had little effect on the depth of texture. It was possible to select an optimum combination of laser processing parameters that obtain different depths of texture without decreasing the surface quality of texture.
关键词： laser processing parameters,micro-morphology,Ti6Al4V alloy,depth of texture,surface texture
更新于2025-09-12 10:27:22