Light Transmission Properties Research Articles

Properties of Multilayer Transparent Bamboo Materials.

The objective of this study is to solve the shortcomings of the current transparent bamboo veneer with a small thickness and low light transmittance by means of lamination. The delignified bamboo templates were vacuum impregnated with an epoxy resin, and the impregnated bamboo templates were laminated with the same radial texture using the viscosity of the epoxy resin to obtain multilayer transparent bamboo (MLTB). The multilayer stacking method can greatly improve the optical and mechanical properties of transparent bamboo. The transparent bamboo with a thickness of 1.2 mm and the delignified bamboo with a volume fraction of 44.8% prepared by multilayer stacking exhibited an improved total optical transmissivity of up to 78.6%, while the highest transmittance of bamboo (0.9 mm thick) without multilayer stacking treatment was only 10.4%. Compared with the single-layer transparent bamboo with a thickness of 2.1 mm, the maximum tensile strength of the seven-layer transparent bamboo was 4 times that of the single-layer transparent bamboo. Therefore, MLTB can compensate to a certain extent for the low light transmission and poor mechanical properties of single-layer transparent bamboo. Overall, MLTB shows a richer and more layered texture, which has more esthetic value. It is a kind of natural transparent material with good light transmittance and excellent mechanical properties, which has a good development prospect as a structural material in the fields of construction, household, and electronic products.

A strategy of finely optimizing WOX electrochromic layers for application in flexible ATF-ECDs

In this study, tungsten oxide (WOX) thin films were prepared by reactive magnetron sputtering at different oxygen (O2) fluxes for application in flexible all-thin-film electrochromic devices (ATF-ECDs) with a device configuration of PET/ITO/NiOX/Ta2O5/WOX/ITO. The target voltage vs. O2 flux curve presents two sputtering mode zones, where distinct target voltages reflect the specific target surface states. The WOX thin film deposited at the O2 flux of 4.5 sccm, which sites at the onset point reaching to the maximal target voltage, exhibits amorphous structure, relatively loose morphology, proper chemical compositions, high light transmittance and best electrochemical properties. The corresponding flexible ATF-ECD performs excellent electrochromic performances with high light modulation of up to 70%, fast response time and the highest coloration efficiencies at both bleaching and coloring steps.

Surface modification of cellulose originated from different plant sources through TEMPO/Laccase/O2 oxidation

An environmentally friendly 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation system using halogen-free reagents has attracted much attention. At present, cellulose nanofibers (CNFs) with a high carboxyl content can be prepared by TEMPO/laccase/O2 (TLO)- oxidation of hardwood bleached kraft pulp (HBKP) under aqueous conditions, while, the related research is still in its infancy. For example, the further applications of TLO-CNFs and the oxidation effect of the TLO system on cellulose from different sources have not been studied. In this work, cellulose from four different sources, that is, HBKP, softwood bleached kraft pulp (SBKP), bleached bagasse sulfate pulp (BBSP) and microcrystalline cellulose (MCC), was oxidized by using a TLO-oxidation system. All cellulose materials were found to be able to be oxidized successfully regardless of the source, which proved the universality of the TLO-oxidation system. Different from traditional TEMPO/NaBr/NaClO (TBN)-oxidation that introduces major carboxyl groups (0.846–1.154 mmol/g) and minor aldehyde groups (0.041–0.097 mmol/g) to cellulose, carboxyl (0.558–0.615 mmol/g) and aldehyde (0.218–0.235 mmol/g) groups can both be sufficiently introduced on the surface of TLO-oxidized cellulose. Based on the aldehyde groups introduced, the wet strength of the TLO-oxidized cellulose handsheet was greatly improved to 400% of the non-oxidized one due to the formation of hemiacetal linkages. In addition, oxidized cellulose can be isolated to homogeneous TLO-CNFs or TLO-cellulose nanocrystals (CNCs), and TLO-CNFs (CNCs) can easily be processed into films and hydrogels with high light transmittance and excellent mechanical properties. Remarkably, compared to the other TLO-CNFs, TLO-CNFs (BBSP) has higher aspect ratio with thinner width (nanofibers as thin as 2 nm can be achieved). Thus, the mechanical properties of TLO-CNFs (BBSP) assembled films and hydrogels were superior to others. These all providing significance and promising prospects for the applications of TLO-oxidation systems, meantime, the distinctive characteristics of TLO-CNFs (BBSP) were explored.

Harvesting Solar Energy from Asphalt Pavement

This study aims at designing and developing a new technique to harvest solar energy from asphalt pavements. The proposed energy harvester system consists of a pavement solar box with a transparent polycarbonate sample and a thin-film solar panel. This device mechanism can store energy in a battery charged over daytime and later convert it into electric power as per demand. A wide range of polycarbonate samples containing different thicknesses, elastic moduli, and light transmission properties were tested to select the most efficient materials for the energy harvester system. Transmittance Spectroscopy was conducted to determine the percent light transmission property of the polycarbonate samples at different wavelengths in the visible spectrum. Finite Element Analysis modeling of the pavement–tire load system was conducted to design the optimal energy harvester system under static load. It was followed by the collection of data on the generated power under different weather conditions. The energy harvesters were also subjected to vehicular loads in the field. The results suggest that the proposed pavement solar box can generate an average of 23.7 watts per square meter continuously over 6 h a day under sunny conditions for the weather circumstances encountered in South Texas while providing a slightly smaller power output in other weather circumstances. It is a promising self-powered and low-cost installation technique that can be implemented at pedestrian crossings and intersections to alert distracted drivers at the time of pedestrian crossing, which is likely to improve pedestrian safety.

A novel and efficient technology of depositing Al2O3 film for OLEDs thin film encapsulation

Organic light-emitting diode devices (OLEDs) industry is developing rapidly, however, OLEDs are very sensitive to oxygen and water, determining how to achieve better barrier effect is one of the main challenges of flexible OLEDs technology. Based on the filtered cathode vacuum arc (FCVA) technology, a dense aluminum oxide (Al2O3) film with a thickness of about 100 nm was grown at room temperature for OLEDs encapsulation. The composition, structure, surface roughness, refractive index, light transmittance and other physical properties of the film were analyzed. The water vapor transmission rates (WVTRs) of the films were tested at 85 °C and 85% relative humidity (R.H.). Photoluminescence spectrum (PL) test was carried out to study the luminescence ability of tris(8-hydroxyquinoline) aluminum (Alq3) before and after the deposition of Al2O3 film. The results show that the amorphous Al2O3 film with dense structure prepared by FCVA has high visible light transmittance. The Al2O3 film reduces the WVTRs of the polyethylene naphthalate (PEN) film by four orders of magnitude and maintains the light-emitting performance of the organic light-emitting layer. These results indicate that the FCVA technology is a feasible method for preparing barrier films of flexible OLEDs.

Facile Single-step Preparation of Cellulose Nanofibers by TEMPO-mediated Oxidation and Their Nanocomposites

ABSTRACT Water hyacinth (Eichhornia crassipes) with a lignin concentration of 4.15% was directly oxidized by the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation without any pre-treatments (alkaline and bleaching). After oxidation, TEMPO-oxidized cellulose nanofibers (CNFs) with widths between 5 and 10 nm were successfully disintegrated. The improvement in crystallinity associated with the decrease in thermal properties was observed for TEMPO-oxidized CNFs in comparison with those features of the untreated fibers. Most lignin was eliminated after the oxidation while the remaining of hemicellulose was observed in the treated nanofibers. The transformation from hydroxyl groups to sodium carboxylic groups was confirmed by Fourier-transform infrared spectroscopy. The application of the prepared TEMPO-oxidized CNFs in ethylene vinyl acetate copolymer (EVA) nanocomposites was studied, and results showed that no degradation in the light transmittance and thermal properties was observed with the introduction of TEMPO-oxidized CNFs. The improvement of ~30% for tensile modulus was noticeable with the incorporation of 1 wt% TEMPO-oxidized CNFs while the tensile strain of the nanocomposites was close to that of the neat EVA films. CNFs from lignin-poor water hyacinth using the direct TEMPO-oxidation process would be a candidate to replace wood-derived CNFs for specific applications such as composites, coatings, packaging and electronic devices.

Flexible, transparent, strong and high dielectric constant composite film based on polyionic liquid coated silver nanowire hybrid

High dielectric constant films with excellent flexibility, transparency and high strength are key materials for flexible electronic devices. Herein, a novel kind of functional hybrid (AgNW@PIL) was synthesized by forming a layer of polyionic liquid (PIL) on surfaces of silver nanowires (AgNWs), which was then added into poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) to develop a series of unique high dielectric constant films (AgNW@PIL/PVDF-HFP). Comprehensive performances of AgNW@PIL/PVDF-HFP films were studied and compared with those of AgNW/PVDF-HFP films and related composite films in literature. With the increase of AgNW@PIL content, the dielectric constant and mechanical strength significantly improve, while the light transmittance gradually decreases. At the same filler content and frequency, AgNW@PIL/PVDF-HFP has higher dielectric constant, lower dielectric loss, higher light transmittance and better mechanical properties than AgNW/PVDF-HFP. The mechanism behind these attractive results is contributed to different microstructures between AgNW/PVDF-HFP and AgNW@PIL/PVDF-HFP. Specifically, different from AgNW, AgNW@PIL has good dispersibility in PVDF-HFP, and form more micro-capacitor structure and good interface polarization effect; besides, PIL coating plays a significant role in suppressing the dielectric loss of composite films. AgNW@PIL/PVDF-HFP with only 0.4 wt% AgNW@PIL simultaneously has high tensile modulus (1152.2 MPa), high tensile strength (30.9 MPa) and large elongation at break (181.0%).

Comparative Spectrophotometer Analysis of Ultraviolet-light Filtering, Blue-light Filtering, and Violet-light Filtering Intraocular Lenses.

PurposeTo compare the light transmittance property of seven currently used intraocular lens (IOL) models by spectrophotometer data.MethodsLight transmission spectra of seven IOL models were assessed with a spectrophotometer. The transmittance properties were analyzed in 1 nm units from 350 nm wavelength to 800 nm.ResultsThree ultraviolet filtering IOL models (ZCB00, XC1-SP, and AT LISA 809M) showed nearly full transmittance of the light from 400 to 500 nm, while steeply attenuating light with shorter wavelengths in various degrees. Three blue-light filtering IOLs (yellow-tinted IOLs; XY1, SN60WF, and TNFT00) showed a slow-sloped increase of light transmission between 400 to 500nm. Among the three, XY1 showed different degree of inclination, showing a steeper slope than SN60WF and TNFT00. The violet-light filtering IOL (ZFR00V) showed a rapid increase of the transmission at around 435 nm wavelength, which is similar to ultraviolet filtering IOLs.ConclusionsThe seven different IOLs measured showed different characteristics of light transmission depending on the properties of each material and color. Blue-light filtering IOLs tend to blocked a wide range of wavelength up to 500 nm, but rather were not effective at the range of 400 to 430 nm. Violet-light filtering IOL showed advantages in filtering the high-energy wavelength, around 430 nm, having a potential risk to retina and allowing the transmission of useful blue and green wavelength which is necessary for a better scotopic contrast sensitivity.

Characteristics of Functional Film Synthesized on the Cover Glass of Photovoltaic Modules

In this study, the characteristics of functional films were investigated according to the number of coatings and their heat treatment times. The functional coating films were deposited on glass substrates made of the same material as the cover glass of photovoltaic (PV) modules. Each film was coated once by brushing with a special silica-based solution, and each heat treatment was done using a hot-air fan for 2 min at 300 °C. The substrates were coated once, twice, and thrice, respectively, and were annealed once, twice, and thrice by drying and cooling alternately. The specimens were then analyzed for their anti-pollution properties, contact angles, light transmittance, and mechanical properties. The anti-pollution function was confirmed through a self-cleaning test, while the contact angle and light transmittance were examined using special equipment. Mechanical properties, including hardness and adhesion, were confirmed using the standard hardness testing method (ASTM D3363) such as those using an H-9H, F, HB, or B-6B pencil (Mitsubishi, Japan) and a standard adhesion testing method (ASTM D3359). It was confirmed that the film coated once yielded a very low contact angle of 8.9° and very good anti-pollution properties. Its adhesion and strength also showed high values of 5B and 9H, respectively.

Developing a green film from locust bean gum/carboxycellulose nanocrystal for fruit preservation

In order to prepare a film with good mechanical and barrier property for fruit preservation, the locust bean gum (LBG) coating was reinforced by carboxycellulose nanocrystal (C-CNC). The effect of C-CNC on the films was studied by analyzing the morphology, thermal stability, mechanical property, light transmittance and barrier property of the composite films. SEM indicated that LBG and C-CNC had good compatibility and C-CNC was dispersed in the LBG matrix well. The Fourier transform infrared spectroscopy analysis showed that there was no new chemical bond formed between LBG and C-CNC. The tensile strength (TS) and elongation at break (EB) of the LBG/C-CNC films increased by 43.69% and 49.13%, respectively. The light transmittance of LBG/C-CNC films at 500 nm increased from 48.84 to 56.49%. The water vapor transmission rate and oxygen transmission rate decreased from 7.05×10−11 and 2.75 to 4.71×10−11 g m − 1 s − 1 Pa−1 and 0.83 cm3 mm m − 2 day−1 atm−1, respectively. LBG/C-CNC coatings reduced the weight loss rate of strawberries by 19.42% and could be easily peeled off after soaked in water for 10 min and without affecting their taste. Therefore, the work provides a feasible and green method for extending the shelf life of strawberries and cherry tomatoes.

Hydrogels derived from acellular porcine corneal stroma enhance corneal wound healing

Acellular cornea derived hydrogels provide significant advantages in preserving native corneal stromal keratocyte cells and endothelial cells. However, for clinical application, hydrogel physical properties need to be improved, and their role in corneal epithelial wound healing requires further investigation. In this study, an acellular porcine corneal stroma (APCS) hydrogel (APCS-gel) was successfully prepared from 20 mg/ml APCS, demonstrated optimal light transmittance and gelation kinetic properties and retained critical corneal ECM of collagens and growth factors. Compared with fibrin gel, the APCS-gel had a higher porosity ratio and faster nutrition diffusion with an accompanying improvement in the proliferation of primary rabbit corneal epithelial cells (RCECs) and stromal cells (RCSCs). These corneal cell types also displayed improved viability and cellular infiltration. Furthermore, the APCS-gel provides significant advantages in the preservation of RCECs stemness and enhancement of corneal wound healing in vitro and in vivo. After 7 days of culture, 3-4 layers of RCECs were formed on the APCS-gel in vitro, while only 1-2 layers were found on the fibrin gel. More corneal stem/progenitor cell phenotypes (K12-, p63+, ABCG2+) and proliferation phenotypes (Ki67+) were detected on the APCS-gel than fibrin gel. Using a corneal epithelial wound healing model, we also found faster reepithelization in corneas that received APCS-gel compared to fibrin gel. Additionally, our APCS-gel demonstrated better physical and biological properties when compared to Tisseel, a clinically used type of fibrin gel. In conclusion, our APCS-gel provided better corneal epithelial and stromal cell biocompatibility to fibrin gels and due to its transparency and faster gelation time could potentially be superior for clinical purposes. Statement of significanceExtracellular matrix (ECM) can be used to provide tissue specific physical microstructure and biochemical cues for tissue regeneration. Here, we produced an ECM hydrogel derived from acellular porcine cornea stroma (APCS-gel) that retained critical biological characteristics of the native tissue and provided significant transparency and fast gelation time. Our data demonstrated that the APCS-gel was superior to clinically used fibrin gel, as the APCS-gel showed high porosity and permeability, better corneal stromal keratocytes infiltration, increased cellular proliferation and retention of corneal epithelial cells stemness. The APCS-gel improved corneal wound healing in vitro and in vivo. This APCS-gel may have clinical utility for corneal diseases, and the more general approach used to make this hydrogel might be used in other tissues.

A Reinforcement Learning-Based Approach to Automate the Electrochromic Glass and to Enhance the Visual Comfort

Daylight is important for the well-being of humans. Therefore, many office buildings use large windows and glass facades to let more daylight into office spaces. However, this increases the chance of glare in office spaces, which results in visual discomfort. Shading systems in buildings can prevent glare but are not effectively adapted to changing sky conditions and sun position, thus losing valuable daylight. Moreover, many shading systems are also aesthetically unappealing. Electrochromic (EC) glass in this regard might be a better alternative, due to its light transmission properties that can be altered when a voltage is applied. EC glass facilitates zoning and also supports control of each zone separately. This allows the right amount of daylight at any time of the day. However, an effective control strategy is still required to efficiently control EC glass. Reinforcement learning (RL) is a promising control strategy that can learn from rewards and penalties and use this feedback to adapt to user inputs. We trained a Deep Q learning (DQN) agent on a set of weather data and visual comfort data, where the agent tries to adapt to the occupant’s feedback while observing the sun position and radiation at given intervals. The trained DQN agent can avoid bright daylight and glare scenarios in 97% of the cases and increases the amount of useful daylight up to 90%, thus significantly reducing the need for artificial lighting.

Development and characterisation of packaging film from Napier cellulose nanowhisker reinforced polylactic acid (PLA) bionanocomposites

A packaging material that is environment-friendly with excellent mechanical and physicochemical properties, biodegradable and ultraviolet (UV) protection and thermal stability was prepared to reduce plastic waste. Six different concentrations of Pennisetum purpureum/Napier cellulose nanowhiskers (NWCs) (i.e. 0, 0.5, 1.0, 1.5, 2.0, and 3.0 wt%) were used to reinforce polylactic acid (PLA) by a solvent casting method. The resulting bionanocomposite film samples were characterised in terms of their morphology, chemical structure, crystallinity, thermal degradation and stability, light transmittance, water absorption, biodegradability, and physical and mechanical properties. Field-emission scanning electron microscopy showed the excellent dispersion of NWC in the PLA matrix occurred with NWC concentrations of 0.5–1.5 wt%. All the bionanocomposite film samples exhibited good thermal stability at approximately 343–359 °C. The highest water absorption was 1.94%. The lowest transparency at λ800 was 16.16% for the PLA/3.0% NWC bionanocomposite film, which also has the lowest UVA and UVB transmittance of 7.49% and 4.02%, respectively, making it suitable for packaging materials. The PLA/1.0% NWC film exhibited the highest crystallinity of 50.09% and high tensile strength and tensile modulus of 21.22 MPa and 11.35 MPa, respectively.

Exploration of polyvinylidene difluoride (PVDF) for improvement of weathering resistance of textile substrates

Coated and laminated fabrics intended for out-door application suffer from property degradation due to hazardous environmental factors, which results in poor durability and limited shelf-life. In this study, polyvinylidene difluoride (PVDF) film having completely ultraviolet (UV) blocking property was developed by solution casting method with optimizing different process parameters. UV blocking property was achieved by pigmentation of pristine PVDF films using titanium dioxide (TiO2). Various characterizations and tests were carried out to determine mechanical, thermal, EDX, FTIR and light transmission properties etc. in case of pristine and pigmented films and the results obtained were analyzed to judge the stability, structure and suitability of the developed films. Pigmented film was then laminated with light sensitive textile substrate by adhesion bonding method. The laminated fabric was subjected to natural and artificial weathering conditions for assessment of efficacy of developed film. The obtained results indicated that film laminated sample exhibited excellent weathering protection compared to control sample (without film) which was evaluated in terms of tensile strength loss after exposure.

Ab initio study of photoelectric properties in ZnO transparent conductive oxide

Zinc oxide is regarded as a third generation transparent conductive film which can replace indium doped tin oxide. It can be widely used in the electrodes of solar cells, the display of electronic instruments and other devices. In this paper, the photoelectric properties of ZnO thin films and their different growth directions were studied, and the best growth direction was obtained. The ZnO system was calculated by density functional theory. The band structure, density of states and other electronic properties of the stable structure are calculated by using Quantum Espresso program. It is found that the Valence Band Maximum and Conduction Band Minimum of ZnO (002) crystal plane both pass through the Fermi level, and the system exhibits semi-metallic properties, which has an important effect on the electrical properties. The band structure is interpolated by wannier90 program, and the precise maximum localized Wannier functions are obtained. Phonons properties are studied by density functional perturbation theory, and the accurate phonon dynamic matrix and the electron phonon coupling matrix elements are obtained. Based on that, the Perturbo program is used to solve the Boltzmann Transport Equation by using relaxation time approximation and electron phonon coupling theory. The scattering rate and relaxation time under different temperature are obtained and the reason why the conductivity and mobility decrease with the increase of temperature is analyzed. In the optical properties of the calculation, the time-dependent density functional theory and epsilon.x program are used to solve the Kohn–Sham equation, and then find out the refractive index, absorption coefficient, visible light transmittance and other important optical properties by obtaining the dielectric function. Combined with the analysis of electrical and optical properties, the (002) crystal plane is determined to be the best growth direction, which is well consistent with the preferred orientation obtained from the experiment. Therefore, it provides a theoretical basis and support for the preparation of better ZnO thin films. The work in this paper fills the blank of theoretical research on ZnO.

PH-responsive antibacterial film based polyvinyl alcohol/poly (acrylic acid) incorporated with aminoethyl-phloretin and application to pork preservation

This study demonstrates a pH-responsive antibacterial film based on polyvinyl alcohol/poly (acrylic acid) incorporated with aminoethyl-phloretin (PVA/PAA-AEP) for intelligent food packaging. The thermal, mechanical, barrier and light transmittance properties of PVA/PAA are enhanced by PAA presence of ≤6%. The interactions between PVA and PAA were hydrogen and ester bonds. The pH-responsive characteristic is dependent on the protonation/deprotonation tendency of the carboxylic groups on PAA in acidic/alkaline environment. The PVA/PAA3 is selected for the incorporation of AEP and its pH-responsive swelling follows Ritger-Peppas and Schott second-order models. The AEP is hydrogen bonded with the matrix of PVA/PAA3 and the release of AEP is pH-responsive and a rate-limiting step following the First-order model. With pH decrease, the predominant release control was gradually changing from polymer relaxation to Fick diffusion. The PVA/PAA3-AEP films demonstrate AEP content dependent antioxidant and antimicrobial activities. Furthermore, the antibacterial efficiency against Listeria monocytogenes and Staphylococcus aureus is significantly better than Escherichia coli. The target film PVA/PAA3-AEP3 can effectively prolong the shelf-life of pork (TVB-N < 25 mg/100 g) by 4 days at 25 °C, suggesting its great potential in intelligent food packaging.

Development of transparent composites using wheat straw fibers for light-transmitting building applications

The use of straw to prepare bio-based composite materials is of great significance to achieve sustainable development. Since the efficient utilization of wheat (Triticum aestivum L.) straw is facing severe challenges and needs to be addressed, wheat straw fibers (WSF) were used to make value-added transparent composites for light-transmitting building applications in this study. The transparent composites using wheat straw (TCWS) were successfully prepared by impregnating pre-polymerized methyl methacrylate (MMA) to WSF. The microscopic morphology analysis showed that WSF had a good binding performance with polymethyl methacrylate (PMMA), so the bio-based composites had high light transmittance and mechanical properties. The TCWS with a thickness of 3 mm and 30 wt% WSF had the light transmittance of 74.63 %, haze of 54.87 %, tensile strength of 58.19 MPa and impact strength of 4.26 kJ/m2. Thermal property test of TCWS showed that the heat conductivity of TCWS was 0.07 Wm−1k−1, displaying excellent thermal insulation performance. TCWS also exhibited excellent thermal dimensional stability and UV resistance. Therefore, TCWS has potential application prospects in the field of transparent buildings. The novelties of this study are to convert the low-cost agriculture residues into high-valued transparent composites with improved thermal insulation properties for light-transmitting building applications, compared with wood fiber transparent composites.

Sub-lithic photosynthesis in hot desert habitats.

In hyper-arid soil environments, photosynthetic microorganisms are largely restricted to hypolithic (sub-lithic) habitats: i.e., on the ventral surfaces of translucent pebbles in desert pavements. Here, we combined fluorometric, spectroscopic, biochemical and metagenomic approaches to investigate in situ the light transmission properties of quartz stones in the Namib Desert, and assess the photosynthetic activity of the underlying hypolithic cyanobacterial biofilms. Quartz pebbles greatly reduced the total photon flux to the ventral surface biofilms and filtered out primarily the short wavelength portion of the solar spectrum. Chlorophylls d and f were not detected in biofilm pigment extracts; however, hypolithic cyanobacterial communities showed some evidence of adaptation to sub-lithic conditions, including the prevalence of genes encoding Helical Carotenoid Proteins, which are associated with desiccation stress. Under water-saturated conditions, hypolithic communities showed no evidence of light stress, even when the quartz stones were exposed to full midday sunlight. This initial study creates a foundation for future in-situ and laboratory exploration of various adaptation mechanisms employed by photosynthetic organisms forming hypolithic microbial communities.

Comparison of Multilayer Transparent Wood and Single Layer Transparent Wood With the Same Thickness

In this paper, poplar was used as raw material, sodium chlorite was used to delignify it in acidic environment, and then epoxy resin was vacuum impregnated in the delignified wood template to prepare transparent wood. Moreover, in order to imitate the lamination method of plywood, the multilayer transparent wood was prepared by means of staggered vertical lamination. The purpose of this paper is to study the physical and chemical properties of multilayer transparent wood, and to explore the application potential of multilayer transparent wood as a new material by comparing with single layer transparent wood with the same thickness. The weight of wood components in the transparent wood prepared in this experiment accounts for about 30–45% of the weight of composite materials. Scanning electron microscopy (SEM) measurements, Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) characterization, weight gain measurements, UV transmittance measurements, color difference measurements, water contact angle measurements and mechanical properties measurements were used to study. The results showed that as the thickness of the transparent wood increased, the cracks between the resin and the wood cell wall increased, and the interface showed an uneven state. In the case of the same thickness, the multilayer transparent wood was made by laminating transparent wood sheets, with fewer internal cracks and smooth interfaces. Its light transmittance is better than single layer transparent wood. Moreover, compared with single layer transparent wood with the same thickness, the lightness of multilayer transparent wood decreased, and tended to yellow and red. Due to the removal of lignin, the tensile strength of transparent wood decreased during the preparation process. However, it can be seen from the mechanical strength test that the tensile strength of multilayer transparent wood is much higher than that of single layer transparent wood. To a certain extent, multilayer transparent wood can improve the mechanical strength of transparent wood. To conclude, multilayer transparent wood is a kind of natural transparent material with large thickness, good light transmission and excellent mechanical properties, and it has a good development prospect.

Research on Preparation and Plication of Superhydrophobic rGO Composite

rGO is widely used in aerospace, petrochemical, marine and other fields because of its high conductivity, high thermal conductivity, high specific surface area, high light transmittance and excellent mechanical properties. At the same time, due to its good hydrophobicity, it is not only easier to synthesize superhydrophobic materials, but also improve the mechanical stability and electrothermal properties of the composites, prolong the service life and ensure the service effect. In this paper, a modified Hummer method was constructed to prepare a superhydrophobic reduced graphene oxide (rGO) composite material. The synthesized rGO material was characterized by using an X-ray powder diffractometer, and the results proved the successful preparation of rGO. Scanning electron microscope (SEM) was used to test and analyze the prepared rGO composite material to further verify the successful preparation of superhydrophobic rGO. Finally, the influence of the amount of rGO on the wettability of the material was explored, and it was concluded that when the amount of rGO added was 7.5 mg/mL, the hydrophobic performance was the best.