Suitable Light Research Articles

Research on A Kind of Lightweight Heat-insulating, Sound-insulating and Light-transmitting Concrete Interior Partition Wall Block

The new composite concrete with both lightweight, thermal insulation, heat insulation and light transmission properties is a new type of building The new composite concrete with both lightweight, thermal insulation, heat insulation and light transmission properties is a new type of building material with energy saving and consumption reduction functions. This paper integrates the research status of scholars in this field at home and abroad, realises the lightweight of blocks by studying the properties of lightweight aggregate concrete and porous concrete, and selects suitable light- transmitting materials, tests the light transmittance and mechanical properties of concrete blocks after adding light-transmitting materials, then analyzes the advantages and disadvantages of the sound insulation effect produced by adding soundproofing materials made from different materials to concrete blocks, and selects the best sound insulation effect by adding soundproofing materials to concrete blocks. concrete blocks, and selects the best soundproofing material for the comprehensive performance. Then we analyze the advantages and disadvantages of Then we analyze the advantages and disadvantages of adding different sound insulation materials into concrete blocks, and select the best sound insulation material with comprehensive performance. the same time of realising the three properties of light weight, sound insulation and light transmittance, we further study the effect of adding different thermal insulation materials on the thermal insulation effect of the blocks, and select the concrete blocks with the best thermal insulation performance.

Structural and Photoluminescence Characteristics of a Novel Single‐Phase White‐Emitting Phosphor SrBi2Nb2O9:Dy3+

A group of white light‐emitting phosphors SrBi2Nb2O9:xDy3+ (SBN:xDy3+) are prepared by high‐temperature solid reaction. The crystal phase, morphology, and photoluminescence (PL) characteristics of the prepared SBN:xDy3+ are analyzed. The X‐ray diffraction results prove that the synthesized samples are pure phase, in which the shift of the main peak depicted that crystal interplanar distance decreases after Dy3+ replacing Bi3+. The scanning electron microscope results show that the average crystal size of the sample is ≈1–10 μm. Energy dispersive X‐ray spectroscopy shows that the ratio of element composition of the SBN:xDy3+ is similar to the theoretical calculation. The PL excitation illustrates the excitation peaks mainly exist at 389, 399, 426, and 450 nm due to the transitions of Dy3+. For PL, the emission peaks of samples with different doping concentrations are centered at 479 and 573 nm. The ratio of yellow intensity to blue intensity indicates that Dy3+ is located at a high symmetry site, which has the possibility to produce suitable white light. The Commission Internationale de l’Eclairage coordinates of the SBN:xDy3+ are located near the standard white light coordinate. All these results prove that SrBi2Nb2O9:xDy3+ can be a potential material in the white light application.

Removal of Emerging Organic Pollutants by Zeolite Mineral (Clinoptilolite) Composite Photocatalysts in Drinking Water and Watershed Water

One of the most challenging problems for people around the world is the lack of clean water. In the past few decades, the massive discharge of emerging organic pollutants (EOPs) into natural water bodies has exacerbated this crisis. Considerable research efforts have been devoted to removing these EOPs due to their biotoxicity at low concentrations. Heterogeneous photocatalysis via coupling clay minerals with nanostructured semiconductors has proven to be an economical, efficient, and environmentally friendly technology for the elimination of EOPs in drinking water and watershed water. Natural zeolite minerals (especially clinoptilolites) are regarded as appropriate supports for semiconductor-based photocatalysts due to their characteristics of having a low cost, environmental friendliness, easy availability, co-catalysis, etc. This review summarizes the latest research on clinoptilolites used as supports to prepare binary and ternary metal oxide or sulfide semiconductor-based hybrid photocatalysts. Various preparation methods of the composite photocatalysts and their degradation efficiencies for the target contaminants are introduced. It is found that the good catalytic activity of the composite photocatalyst could be attributed to the synergistic effect of combining the clinoptilolite adsorbent with the semiconductor catalyst in the heterogeneous system, which could endow the composites with an excellent adsorption capacity and produce more e−/h+ pairs under suitable light irradiation. Finally, we highlight the serious threat of EOPs to the ecological environment and propose the current challenges and limitations, before putting the zeolite mineral composite photocatalysts into practice. The present work would provide a theoretical basis and scientific support for the application of zeolite-based photocatalysts for degrading EOPs.

Unconventional perovskite-to-perovskite tandem cell designed by stacking with large-gap phosphonium-based analogs

We present a material design strategy for stacking large-gap unconventional derivatives on the prevailing hybrid organic–inorganic perovskites, (MA, FA)(Sn, Pb)I3 as a perovskite-to-perovskite tandem cell. To this end, we employ an unconventional structurally well-matched hybrid organic–inorganic perovskite derivative MPSnBr3 with large-sized weakly hybridized A-site methylphosphonium (MP) cations to construct a heterojunction with its structural analogs (MA, FA)(Sn, Pb)I3 to simulate the two subcells of the tandem cell. Compared with the popular ammonium-based perovskites, density-functional theory computation suggests that MPSnBr3 possesses a wider bandgap and lower conduction band minimum level induced by the weak-hybrid MP cations, which can be a more suitable wide-range light absorber than its traditional ammonium counterparts. We show that such a heterostructure exhibits a desirable positive “spike-like’ band offset, resulting in higher Voc and more effective suppression of undesirable carrier recombination. Hence, MPSnBr3 as a structural well-matched absorber can potentially serve as the wide-range subcell in perovskite tandem cell devices.

Construction of functional direct Z-scheme PCN-224@MoS2 heterojunction with high photocatalytic performance by simple solvothermal method

Organic contamination due to overuse of antibiotics and microbial contamination caused by various bacteria not only damage the ecological environment, but also threaten people's health. In this work, the photocatalytic material PCN-224@MoS2 was synthesized using a simple solvothermal method. The successfully synthesized photocatalytic material possesses a direct Z-scheme heterojunction, which effectively separated the photogenerated electrons and holes and suppressed their rapid complexation, leading to an increase in reactive oxygen species (ROS) yield. The degradation experiments showed that PCN-224@MoS2 with a mass ratio of 5:16 exhibited the best degradation ability for the tetracycline hydrochloride (TCH), achieving 96.41% degradation rate in 60 min, which was 5.4 and 4.7 times higher than that of pure PCN-224 and pure MoS2. In addition, the photocatalytic material achieved antibacterial ratios of 99.98% and 99.86% against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively, under suitable light time and concentration. Subsequently, free radical scavenging experiments and the electron-spin resonance (ESR) techniques were used to confirm the types of free radicals and the possible photocatalytic mechanism in the photocatalytic process. The development of PCN-224@MoS2 heterojunction provides a new insight to solve the environmental problems caused by organic pollutants and microbial contamination.

How to illuminate indoor plants sustainably? Tips and tricks to bridge the gap between research and design.

The increasing popularity of biophilic design in architecture and interior design has led to a widespread integration of indoor ornamental plants and green walls. While numerous studies have demonstrated the benefits of such integration for people, only a few have focused on the well-being of the plants themselves. Our latest research project aims to address this gap by exploring suitable lighting conditions for indoor plants, seeking an optimal spectral composition that ensures their well-being, robust growth, and visual appeal, while also optimizing maintenance. Building upon previous applied research, we conducted experiments to analyze the lighting requirements of four species of ornamental plants commonly used indoors. Seven identical room boxes were employed, each illuminated with different light spectra falling within the CCT range of 2800K-5000K. The specific light spectra were meticulously tuned with a focus on the red/blue and red/green ratios, while keeping the photosynthetic photon flux (PPFD) and average illuminance consistent. As a result of this research project, practical guidelines were developed to help lighting designers navigating the intricate world of indoor ornamental plants effectively. By carefully considering the lighting spectrum in the suggested ranges, architects and interior designers can create spaces that not only benefit human occupants but also provide an optimal environment for the well-being and flourishing of indoor plants.

Creating a new yellow and blue combination transparent film for Panax ginseng C.A. Meyer growth based on orthogonal designs

Panax ginseng C.A. Meyer originates from old-growth forest environments, where the light intensity and spectrum reaching the forest bed are influenced by the canopy and humidity. In farmlands, suitable light intensity for cultivation is achieved by controlling the light transmission rate using shading nets, while light quality is regulated by a cover of yellow or blue transparent film. Such films have a light quality distinct from that produced by old-growth forests. Herein, a large composite film was developed by alternating small pieces of yellow and blue transparent film. An orthogonal array was used to evaluate the influence of the small transparent film area (STFA), yellow transparent film (YTF) number, and blue transparent film (BTF) number on the associated changes in ginseng in a range of fluorescence-, photosynthesis-, morphology-, and crop quality-related factors. Our results showed that light intensity was influenced primarily by STFA, which caused an overall decrease, while the light quality ratio was affected primarily by YTF number, which increased the proportion of red light and decreased that of blue light, with corresponding influence on different growth parameters. Based on these observations, an improved yellow and blue combination transparent film (YBCTF) with the following characteristics was established: STFA: 15 × 15 cm, YTF: two pieces, and BTF: three pieces. The improved YBCTF facilitated efficient light energy use by the plants, and led to an increase in leaf area, the per leaf photosynthetic rate, dry root weight, and the per root single ginsenoside yield. The findings present a relatively low-cost approach for optimising the light environment of ginseng cultivated in farmland and other crops in large-scale agricultural settings.

Analysis of Using the Light Pressure Effect to Drive Spacecraft under Complex Conditions

Light pressure driving has attracted widespread attention due to its unique physical properties and potential in various scientific and technological fields. Due to the limitations of current technology and material levels, achieving a macro-level light pressure-driven approach in the short term is unrealistic. A wide range of research areas for light-pressure driving are focused on the micro level and suitable light-pressure materials. Under the current theoretical framework, a light pressure-driven spacecraft with suitable light sail materials is a highly competitive alternative for interstellar navigation. This article mainly simulates the process of light pressure-driven spacecraft accelerating to sub-light speed through laser irradiation on the Earth’s surface and decelerating the returning spacecraft. The article comprehensively considered factors such as laser frequency, sail size, and spacecraft mass during the simulation process and provided simulation results under appropriate conditions. Due to the significant relativistic effect of this process, this paper also considered the red shift and blue shift effects of relativistic light in the simulation process.

Effect of light intensity on nitrogen transformation, enzymatic activity, antioxidant system and transcriptional response of Chlorella pyrenoidosa during treating mariculture wastewater

The nitrogen transformation, enzymatic activity, antioxidant ability and transcriptional response of Chlorella pyrenoidosa (C. pyrenoidosa) treating mariculture wastewater were compared under different light intensities. The microalgal growth, chlorophyll synthesis and nitrogen removal ability of C. pyrenoidosa increased with the light intensity from 3000 to 7000 Lux, whereas they slightly decreased under 9000 and 11,000 Lux. The nitrogen metabolism enzymatic activities displayed obvious differences under different light intensities and affected the nitrogen transformation process. The reactive oxygen species (ROS) production increased with the increase of operational time, whereas it had distinct differences under different light intensities. The changes of antioxidant enzymatic activities were positively correlated with the ROS production. The transcriptional response of C. pyrenoidosa was in accordance with the variation of the photosynthesis, nitrogen assimilation and antioxidant system under different light intensities. This study provides theoretical basis and technical support to select suitable light intensity for algae treating mariculture wastewater.

An approach to ensure joint illumination & communication performance of a forward error corrected indoor visible light communication (VLC) system in presence of ambient light interference

Abstract In recent time of looming radio frequency (RF) spectrum crisis, visible light communication using lighting infrastructure emerged as a potential alternative at an indoor environment. This paper addresses the setback associated with ambient light interference in an indoor Visible Light Communication (VLC) system to ensure joint communication and illumination performance inside an office room. A novel VLC architecture with suitable white light emitting diode (WLED) luminaire arrangement is presented to minimize the dispersion of signal to interference plus noise ratio (SINR) across the room. Luminaires are categorized in two groups viz. data transmitting illuminants and illuminants for lighting purpose. The first group is dedicated to transmit data as well as serves the purpose of illumination. The other set creates only ambient illumination to achieve quality lighting attributes. The proposed forward error corrected receiver configuration discards the ambient light noise originated by the illuminants that serve the ambient illumination. Tail biting convolutional encoder and viterbi decoder are used at the encoding section of the transmitter and decoding section of the receiver respectively to improve bit error rate. Results obtained through MATLAB simulation shows better average bit error rate (BER) in the order of 10−8 measured at uniformly distributed 25 grid points over the working plane. At the same time achieved average horizontal illuminance with good uniformity comply with ISO recommendation.

Metabolomic and Growth Responses of Houttyunia cordata to Varying Light Intensities and Subsequent Effects on Fermented Products

Suitable light intensities were studied to enable sustainable and efficient cultivation of Houttuynia cordata with a high yield of bioactive compounds which later can be a good quality material for fermentation. To achieve this goal, the evaluation of physiological adaptation and elucidation of the metabolic alterations of Houttuynia cordata in response to different light intensities were conducted. Four-month-old H. cordata was exposed to 3 different light intensities: high light, control, and low light (100, 50 and 20 % natural irradiances, respectively). Physiological responses were measured using leaf gas exchange. The same leaf samples were either methanolic extracted for LC-QTOF-MS analysis to generate metabolite fingerprints or fermented for 3 months prior to quercetin quantification. High light treatment had the greatest effects on both the physiology and metabolisms of H. cordata compared to control and low light treatments. Compared to the control, the key results observed in high-light-grown H. cordata were a significant increase in photosynthesis, a decrease in relative chlorophyll contents, the enrichment of the top 3 metabolic pathways (phenylpropanoid biosynthesis, pyruvate metabolism and fatty acid degradation) and increasing quercetin concentrations in both fresh and fermented leaves. Metabolite fingerprints of high light-grown H. cordata were distinctively different from those of the other 2 treatments according to PCA and hierarchical clustering analysis. In conclusion, H. cordata responded to high light intensity by enriching the phenylpropanoid biosynthetic pathway to elevate sunscreen pigments. Additional acetyl-CoA generated from pyruvate metabolism and fatty acid degradation was a key supporting factor in the above response. As high quercetin concentration was observed in both fresh and fermented leaves, this will lead to quality improvement of the fermented products. HIGHLIGHTS The remarkable effects of light intensities on Houttuynia cordata growth and abundance of bioactive compounds are substantial, but the underlying mechanism has never been investigated. Metabolomics technology was applied to gain insight into light-induced metabolic reconfiguration. GRAPHICAL ABSTRACT

Estimation of Economic Spillover Effects under the Hierarchical Structure of Urban Agglomeration Based on Time-Series Night-Time Lights: A Case Study of the Pearl River Delta, China

Urban agglomerations are becoming increasingly important in driving economic development in China. Accurate representation of the economic development status and spillover effects of cities within an urban agglomeration is the foundation of and an effective approach for promoting the coordinated development of that agglomeration. However, current studies of economic spillovers tend to focus on urban agglomerations as a whole, and there is a lack of scrutiny and validation of research data. Therefore, this study proposes a framework for detecting economic spillover effects within an urban agglomeration based on a prolonged night-time light dataset. Firstly, we explored the most suitable night-time light index to characterize the economic status. Then, we used this index to construct the economic network and hierarchical structure of the urban agglomeration. Finally, we explored the heterogeneity of spillover effects under the hierarchical structure. The results of a case study in the Pearl River Delta (PRD) urban agglomeration show that (1) the total night-time light in built-up areas (BNTL) has the highest Pearson correlation coefficient with GDP, which is 0.82; (2) there is an obvious hierarchical structure within the PRD; (3) there are significant and sustained economic spillover effects among the core cities, with Guangzhou–Foshan and Shenzhen–Dongguan having more obvious spillover effects; and (4) the economic spillover effects within the three metropolitan areas have different characteristics. The Guangzhou–Foshan–Zhaoqing metropolitan area is closely linked, to apparent differences in the pace of spillover effects. The Shenzhen–Dongguan–Huizhou metropolitan area has strong close linkages, with strong synchronization of spillover effects. The Zhuhai–Zhongshan–Jiangmen metropolitan area has not yet formed a stable synergistic development relationship. Overall, the framework can effectively reveal the hierarchical structure and different characteristics of economic spillovers within urban agglomerations, which can provide a scientific reference for policy making related to the coordinated development of such agglomerations.

A triazole-based covalent organic framework as a photocatalyst toward visible-light-driven CO2 reduction to CH4.

Solar-light driven reduction of CO2 to CH4 is a complex process involving multiple electron and proton transfer processes with various intermediates. Therefore, achieving high CH4 activity and selectivity remains a significant challenge. Covalent organic frameworks (COFs) represent an emerging class of photoactive semiconductors with molecular level structural tunability, modular band gaps, and high charge carrier generation and transport within the network. Here, we developed a new heterocyclic triazole ring containing COF, TFPB-TRZ, through the condensation reaction between 1,3,5-tris(4-formylphenyl)benzene (TFPB) and 3,5-diamino-1,2,4-triazole (TRZ). The TFPB-TRZ COF with multiple heteroatoms shows suitable visible light absorption, high CO2 uptake capability and an appropriate band diagram for CO2 photoreduction. Photocatalysis results reveal a maximum CO2 to CH4 conversion of 2.34 mmol g-1 with a rate of 128 μmol g-1 h-1 and high selectivity (∼99%) using 1-benzyl-1,4-dihydronicotinamide (BNAH) and triethylamine (TEA) as sacrificial agents. Under similar reaction conditions in the presence of direct sunlight, the TFPB-TRZ COF displays a maximum CH4 yield of 493 μmol g-1 with a rate of 61.62 μmol g-1 h-1, suggesting the robustness and light-harvesting ability of the COF photocatalyst. A femtosecond transient absorption (TA) spectroscopy study shows fast decay of excited state absorption (ESA) in the COF compared to the TFPB building unit due to efficient electron transfer to the catalytic site in the framework. The mechanism of CO2 reduction to CH4 is studied by DFT-based theoretical calculation, which is further supported by an in situ diffuse reflectance infrared Fourier transform spectroscopic (DRIFTS) study. The DFT results reveal that the lone pair of electrons on nitrogen heteroatoms present in the triazole ring of the TRZ moiety help in the stabilization of the CO intermediate during CO2 to CH4 conversion. Overall, this work demonstrates the use of a metal-free, recyclable COF-based photocatalytic system for solar energy storage by CO2 reduction.

Rigidify styryl-pyridinium dyes to benzo[h]coumarin-based bright two-photon fluorescent probes for cellular bioimaging.

Fluorescence imaging of organelles at the cellular level is important for studying biological processes. The development of a highly emissive fluorescent probe that operates under a suitable excitation light source is a key step in high-quality fluorescence imaging. For long-term, high-fidelity fluorescence imaging of mitochondria-related cellular processes using two-photon microscopy and stimulated emission depletion microscopy, we developed a new benzocoumarin-based cationic fluorescent probe (BS-CN) that is far-red emitting, water-soluble, photostable, and very bright in cells. BS-CN showed a remarkably high quantum yield of 0.35 and a large two-photon excited fluorescence action cross-section of 76 GM, enabling the long-term tracking of mitochondria in live cells. In addition, BS-CN exhibited a certain affinity for RNA and stained nucleoli in fixed cells. A comparative assessment of the photophysical properties and bioimaging performance of benzo[h]coumarin-pyridinium and the structurally similar styryl-pyridinium (BS-MN) clearly indicated the importance of structural rigidity for fluorescence efficiency.

Precision spectroscopic measurements of few-electron atomic systems in extreme ultraviolet region

<sec>Precision spectroscopic measurements on the few-electron atomic systems have attracted much attention because they shed light on important topics such as the “proton radius puzzle” and testing quantum electrodynamics (QED). However, many important transitions of few-electron atomic systems are located in the vacuum/extreme ultraviolet region. Lack of a suitable narrow linewidth light source is one of the main reasons that hinder the further improvement of the spectral resolution.</sec><sec>Recently, narrow linewidth extreme ultraviolet (XUV) light sources based on high harmonic processes in rare gases have opened up new opportunities for precision measurements of these transitions. The recently implemented XUV comb has a shortest wavelength of about 12 nm, a maximum power of milliwatts, and a linewidth of about 0.3 MHz, making it an ideal tool for precision measurements in the XUV band. At the same time, the Ramsey comb in the XUV band can achieve a spectral resolution of the kHz range, and may operate throughout the entire XUV band.</sec><sec>With these useful tools, direct frequency spectroscopy and Ramsey comb spectroscopy in the XUV region are developed, and precision spectroscopic measurements of few-electron atomic systems with these methods are becoming a hot topic in cutting-edge science. In this paper, we provide an overview of the current status and the progress of relevant researches, both experimentally and theoretically, and discuss the opportunities for relevant important transitions in the extreme ultraviolet band.</sec>

Dexamethasone phosphate and penetratin co-eluting contact lenses: a strategy to enhance ocular drug permeability

Contact lenses (CLs) have been suggested as drug delivery platforms capable of increasing the drug residence time on the cornea and therefore its bioavailability. However, when targeting the posterior segment of the eye, the drug released from CLs still encounters the barrier effect of the ocular tissues, which considerably reduces the efficacy of administration. This work aims at the development of CLs able to simultaneously deliver an anti-inflammatory drug (dexamethasone sodium phosphate) and a cell-penetrating peptide (penetratin), the latter acting as a drug carrier across the tissues. Hydroxyethyl methacrylate (HEMA)-based hydrogels were functionalized with acrylic acid (AAc) and/or aminopropyl methacrylamide (APMA) to serve as CL materials with increased affinity for the drug and peptide. APMA-functionalized hydrogels sustained the dual release for 8 h, which is compatible with the wearing time of daily CLs. Hydrogels demonstrated suitable light transmittance, swelling capacity and in vitro biocompatibility. The anti-inflammatory activity of the drug was not compromised by the presence of the peptide nor by sterilization. The ocular distribution of the drug after 6 h of CL wearing was evaluated in vivo in rabbits and revealed that the amount of drug in the cornea and aqueous humor significantly increased when the drug was co-delivered with penetratin.

Selection of tramcars for sustainable urban transportation by using the modified WASPAS approach based on Heronian operators

The wrong design of rail system vehicle fleets is one of the most critical problems in terms of urban transportation. Light rail system fleets in many large cities, including Istanbul, consist of various types and feature vehicles. It creates significant problems in integrating each rail system vehicle into the system. In addition, while it is necessary to keep an inventory of spare parts for each different type of vehicle, it requires different qualifications for professionals involved in processes such as maintenance and repair, leading to extra costs. In this context, the study's primary purpose is to determine the most suitable light rail vehicles for urban transportation systems and create vehicle fleets accordingly. In that regard, the study aims to provide a reliable and practical decision-making model that can be used as a roadmap for decision-makers when choosing tramcars to solve these problems. The present work proposes a hybrid procedure integrating the Best and Worst Method (BWM) and Power-Heronian Weighted Aggregated Sum Product Assessment (WASPAS'PH) approaches. The most critical implication of the work indicated that the acquisition cost per tramcar set (0.148) is still the most influential factor. The economic lifespan of tramcars (0.037), the number of seats in a vehicle set (0.041), and energy consumption (0.072) have followed the most significant criterion, respectively. Besides, it highlighted that the A14 Brand CR (0.7819) is the most appropriate option for well-structuring the urban light rail system fleet. An extensive validation test to check the suggested model's robustness confirmed the procedure's stability and consistency.

Optimizing supplemental light spectrum improves growth and yield of cut roses

During the seasons with limited light intensity, reductions in growth, yield, and quality are challenging for commercial cut rose production in greenhouses. Using artificial supplemental light is recommended for maintaining commercial production in regions with limited light intensity. Nowadays, replacing traditional lighting sources with LEDs attracted lots of attention. Since red (R) and blue (B) light spectra present the important wavelengths for photosynthesis and growth, in the present study, different ratios of supplemental R and B lights, including 90% R: B 10% (R90B10), 80% R: 20% B (R80B20), 70% R: 30% B (R70B30) with an intensity of 150 µmol m−2 s−1 together with natural light and without supplemental light (control) were applied on two commercial rose cultivars. According to the obtained results, supplemental light improved growth, carbohydrate levels, photosynthesis capacity, and yield compared to the control. R90B10 in both cultivars reduced the time required for flowering compared to the control treatment. R90B10 and R80B20 obtained the highest number of harvested flower stems in both cultivars. Chlorophyll and carotenoid levels were the highest under control. They had a higher ratio of B light, while carbohydrate and anthocyanin contents increased by having a high ratio of R light in the supplemental light. Analysis of chlorophyll fluorescence was indicative of better photosynthetic performance under a high ratio of R light in the supplemental light. In conclusion, the R90B10 light regime is recommended as a suitable supplemental light recipe to improve growth and photosynthesis, accelerate flowering, and improve the yield and quality of cut roses.

A novel method of determining bias lights for spectral response measurement of GaAs multi-junction laser power converters and its applications

Quantitative electrical analysis of sub-cells is crucial for the designing of high-efficiency GaAs multi-junction laser power converters (MJLPCs). However, finding suitable bias lights to separate the electrical performance of sub-cells is an enormous challenge, due to GaAs MJLPCs being assembled by GaAs p-n junctions. Therefore, this study proposes a novel and general method of determining bias lights for the SR measurement of GaAs MJLPCs based on the variation rules of simulated short-circuit current densities with wavelengths in the sub-cells of GaAs MJLPCs. By the method of determining bias lights, the external quantum efficiency (EQE) curves of a GaAs four-junction LPC have been successfully measured for the first time, which confirms the validity of the method.

An overview of hydrogen production from Al-based materials

Abstract A profound overview of the recent development for on-time, on-demand hydrogen production from light metal-based hydrolysis is presented. Hydrogen energy is one of the clean and renewable energy sources which has been recognized as an alternative to fossil fuels. In addition, aluminum is the most suitable light activity metal for hydrolysis materials attributed to its safety, environmental friendliness, high-energy density, inexpensive, and low density with high strength ratio. In general, dense oxide films formed act as a barrier on aluminum surfaces. Accordingly, effective removal of the oxide film is a key measure in solving the Al–water reaction. In this review, recent advances in addressing the main drawbacks including high-purity aluminum with acid–alkali solutions, nano-powders of aluminum or composite with acid–base solutions, ball-milled nano-powders, alloying blocks, and gas atomization powders are summarized. The characteristics of these three technologies and the current research progress are summarized in depth. Moreover, it is essential to promote low-cost aluminum-based materials based on effective hydrogen production efficiency and explore ways for practical large-scale applications.