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Preparation of high-purity α-Si3N4 nano-powder by precursor-carbothermal reduction and nitridation
摘要： This work investigated the role of natural organic matter (NOM) in the environmental processes of silver nanoparticles (AgNP) and the uptake and accumulation of AgNP in wheat. Different NOMs (Suwannee River humic acids [SRHA], fulvic acid [FA]) and Ag elements (Ag(0) and Ag+) were incubated in a hydroponic media for 15 days. The results showed that the NOM (10 mg C L-1) altered the dissolution, stabilization, uptake and accumulation of AgNP. The dissolution of AgNP declined in the presence of NOM. Compared with FA, the dissolved Ag+ decreased much more from 0.30 mg L-1 to 0.10 mg L-1 in the presence of SRHA. The fluorescence quenching results indicated that SRHA exhibited stronger binding to Ag+ than that of FA, and the quenching constants Ksv were 0.1309 (SRHA) and 0.0074 (FA), respectively. CeO, CeH, CeOeC, and MeeOH were involved in the interaction between NOM and AgNP. The NOM decreased the accumulated content of Ag in wheat. Hence, NOM alleviated the inhibition of AgNP to wheat growth. SRHA reduced the Ag content of wheat roots approximately 3-fold. These results clearly indicated the importance of NOM on altering the behavior, fate and toxicity of AgNP in an environment.
关键词： Wheat,Nanoparticle fate,Accumulation,Natural organic matter,Silver nanoparticle
更新于2025-11-19 16:46:39
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Mechanical analysis of the interface bonding state of a TiO2 film/Si substrate
摘要： TiO2 film is prepared on the surface of a natural oxide layer of a monocrystalline silicon substrate via RF magnetron sputtering. HRTEM (High Resolution Transmission Electron Microscope) imaging and EDX spectroscopy are performed on the sample interface, demonstrating that the film sample has a two-layer structure. Combined with XRD, the analysis shows that the upper film is a crystalline TiO2 film with a thickness of approximately 30 nm and that the lower film is a natural amorphous SiO2 oxide film with a thickness of approximately 22 nm. A geometric phase analysis (GPA) and Hooke's law are used to analyse the stress and bonding state at the interfaces between the monocrystalline silicon substrate and the natural oxide layer, between rutile TiO2 and the natural oxide layer, and between anatase TiO2 and the natural oxide layer. It is concluded that the interface bonding state of the monocrystalline silicon/natural oxide layer is good and that the interface bonding state at the interface between rutile and the natural oxide layer is better than that between anatase and the natural oxide layer.
关键词： geometric phase analysis,Hooke's law,natural oxidation,interface bonding states,TiO2
更新于2025-11-14 17:04:02
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Translating chemometric analysis into physiological insights from in vivo confocal Raman spectroscopy of the human stratum corneum
摘要： The superficial layer of the skin, the stratum corneum (SC), consists of corneocytes surrounded by lipid regions and acts as a protective barrier for the body against water loss, toxic agents and microorganisms. As most substances permeate the stratum corneum through the lipid regions, lipid organization is considered crucial for the skin barrier function. Here, we investigate the potential of in vivo confocal Raman spectroscopy to describe the composition and organization of the SC. Confocal Raman spectroscopy is finding increasing use in the characterization of skin in biomedical, pharmaceutical and cosmetic applications. In this work, we analyze the spectra using chemometric methods and obtain principal components that correspond to the primary skin constituents: protein (keratin), natural moisturizing factor (NMF), water and lipid contributions in both ordered (orthorhombic) and disordered structural organization. By identifying these important components of the SC, these results highlight the utility of this in vivo, non-invasive, and depth resolved tool at the forefront of skin research.
关键词： Skin barrier,Natural moisturizing factor,Multivariate curve resolution,Keratin,Lipid organization
更新于2025-11-14 15:16:37
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Two-step synthesis of reduced graphene oxide with columnar-shaped ZnO composites and their photocatalytic performance with natural dye
摘要： Composites of ZnO with reduced graphene oxide were prepared in two-step synthesis process with constant temperature in variation with pH values. The synthesized composites were characterized and the results suggest that ZnO structure in the composites has a columnar morphology with an average diameter ranging 0.8–1.57 μm. The obtained properties of the composites with the present method confirmed that the material morphology influences the absorption and photocatalytic activity of natural dye under sunlight irradiation. The result shows that the maximum degradation efficiency is 64.40% achieved in 120 min.
关键词： Zinc oxide,Columnar morphology,Photocatalytic activity,Reduced graphene oxide,Natural dye
更新于2025-09-23 15:23:52
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Study on the enhancement of photocatalytic environment purification through ubiquitous-red-clay loading
摘要： Tungsten oxide (WO3) is regarded as a promising visible-light-sensitive photocatalyst, but its activity is not high. Further enhancement of its activity has been anticipated using techniques such as loading of a cocatalyst to apply the oxide to indoor environmental remediation; Pt has been reported as a good cocatalyst for WO3 photocatalysis. However, Pt is precious and expensive metal. Thus, in this study, we sought to find a ubiquitous cocatalyst and suitable photocatalyst system. As a result, this study revealed that loading a ubiquitous material of red-clay enhanced WO3 photocatalytic activity remarkably. As photocatalyst samples, mixtures consisting of the clay and WO3 with different weight ratios were prepared using a simple kneading method. Their photocatalytic activity was evaluated from decomposition of harmful organic contaminant, 2-propanol into CO2 under visible-light irradiation. The WO3 with 10% of the clay loading showed the highest activity among the samples and much higher activity than pure WO3. This higher activity might derive from the clay’s promotion of H2O2 decomposition and charge separation (holes and electrons). The H2O2 was generated from photocatalytic O2 reduction. This formation and accumulation on the pure WO3 surface led to decreased activity.
关键词： TiO2,Zeolite,Natural mineral,Optical absorption,Remediation
更新于2025-09-23 15:23:52
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Sustainable Liquid Luminescent Solar Concentrators
摘要： Luminescent solar concentrators (LSCs) are photovoltaic (PV) complementary devices to overcome the mismatch between the Si-based PV cells, response and the solar spectrum, allowing PV urban integration. Challenges for the luminescent layer include the use of abundant and sustainable natural organic molecules. Here, LSCs composed of a glass container and based on bundles of cylindrical hollow-core plastic optical fibers filled with aqueous solutions of R-phycoerythrin (R-PE), extracted from Gracilaria sp. algae are presented. The R-PE solutions absorb in the UV/visible spectral range (300–550 nm) and convert this radiation into red-emission (550–700 nm) with a maximum absolute quantum yield of ≈0.39. In this work, LSCs with distinct geometries are reported, in which the R-PE emission yields optical conversion efficiency values up to ≈6.88% and ≈4.74% for a planar device and for a bundle of cylindrical LSCs, respectively, which are the largest values known for liquid-based LCSs using sustainable emitting centres. Moreover, the coupling of the LSCs to commercial Si-based PV devices yields power conversion efficiency values of ≈0.27% (planar) and ≈23.03 × 10?3%, (bundle). These values illustrate the potential of this approach for the development of natural-based LSCs meeting the requirements of reliable, sustainable, and competitive energy systems.
关键词： sustainability,organic–inorganic hybrids,luminescent solar concentrators,R-phycoerythrin,natural optically active center,bundles
更新于2025-09-23 15:23:52
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Thermal performance analysis of a novel linear cavity receiver for parabolic trough solar collectors
摘要： The trough solar thermal power generation system is one of the most mature solar thermal power generation systems. A novel major arc-shaped linear cavity receiver with a lunate channel based on the black cavity effect principle for parabolic trough solar collectors is proposed in this work. The effects of the inclination angle, collecting temperature, surface emissivity and aperture width on the heat loss are thoroughly analyzed with a two-dimensional numerical model coupling natural convection with surface radiation. In addition, the thermal performance of the proposed linear cavity receiver is compared with that of the Solel’s UVAC series evacuated collector tube. The results show that: (1) The natural convection heat loss is significantly affected by the inclination angle, while the radiation heat loss is mainly affected by the surface emissivity and the collecting temperature. (2) The aperture width of the receiver has a great impact on the thermal performance. The larger the aperture width is, the greater the heat losses. However, the aperture width can also affect the optical performance and the manufacturing cost. The reasonable aperture width for this kind of linear cavity receiver is about 50–70 mm with consideration of all these factors. (3) The proposed linear cavity receiver demonstrates comparative or even better thermal performance as traditional evacuated collector tubes, especially in high temperature range. In general, the proposed linear cavity receiver has the comparative shape and size as the traditional evacuated collector tubes. More importantly, it has the advantages of raising the collecting temperature and reducing the production and maintenance costs. Therefore, it can be used to replace the evacuated collector tube which has poor performance due to long-term operation.
关键词： Cavity receiver,Parabolic trough solar collector,Surface radiation,Natural convection,Thermal performance,Linear receiver
更新于2025-09-23 15:23:52
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Understanding doped perovskite ferroelectrics with defective dipole model
摘要： Leaf stoichiometry (nitrogen (N), phosphorus (P) and N:P ratio) is not only important for studying nutrient composition in forests, but also reflects plant biochemical adaptation to geographic and climate conditions. However, patterns of leaf stoichiometry and controlling factors are still unclear for most species. In this study, we determined leaf N and P stoichiometry and their relationship with soil properties, geographic and climate variables for Cyclocarya paliurus based on a nation-wide dataset from 30 natural populations in China. The mean values of N and P concentrations and N:P ratios were 9.57 mg g?1, 0.91 mg g?1 and 10.51, respectively, indicating that both leaf N and P concentrations in C. paliurus forests were lower than those of China and the global flora, and almost all populations were limited in N concentration. We found significant differences in leaf N and P concentrations and N:P ratios among the sampled C. paliurus populations. However, there were no significant correlations between soil properties (including organic C, total N and P concentrations) and leaf stoichiometry. The pattern of variation in leaf N concentration across the populations was positively correlated with latitude (24.46? N–32.42? N), but negatively correlated with mean annual temperature (MAT); meanwhile, leaf N concentration and N:P ratios were negatively correlated with mean temperature in January (MTmin) and mean annual frost-free period (MAF). Together, these results suggested that temperature-physiological stoichiometry with a latitudinal trend hold true at both global and regional levels. In addition, the relationships between leaf stoichiometry and climate variables provided information on how leaf stoichiometry of this species may respond to climate change.
关键词： N:P ratio,geographic variations,nitrogen,climate variables,Cyclocarya paliurus,phosphorus,natural populations,leaf stoichiometry
更新于2025-09-23 15:23:52
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Effect of dissolved natural organic matter on the photocatalytic micropollutant removal performance of TiO2 nanotube array
摘要： The TiO2 nanotube array (TNA) is a promising photocatalyst for removal of micropollutants from water, but better understanding on its applicability in complex water matrices is still desired. Therefore this study investigates the effect of dissolved natural organic matter (NOMs) on 4-chloro-2-methylphenoxyacetic acid (MCPA, a typical micropollutant found in many water bodies) removal performance of TNA. The present study shows that although in bulk liquid phase NOMs would undergo photosensitization that can contribute to MCPA removal, the overall effect of NOMs on MCPA removal is detrimental due to the interaction between NOMs and the TNA surface: the total removal of MCPA decreased from 94.3% to 62.0% and 61.8%, in the presence of only 5 mg/L SWR-NOM and UMR-NOM respectively. Acidic pH was found to be able to mitigate the detrimental effect of NOMs (the total removal of MCPA was only decreased from 94.5% to 83.3% and 88.8% under acidic pH, in the presence of 15 mg/L SWR-NOM and UMR-NOM respectively), and the photosensitization effect of NOMs was strengthened; while under alkaline pH conditions the detrimental effect of NOMs completely vanished (the total removal of MCPA increased from 45.7% to 55.7% and 60.5% in the presence of 15 mg/L SWR-NOM and UMR-NOM respectively). Two commonly present co-existing anions, i.e. phosphate and bicarbonate, also mitigate the detrimental effect of NOMs. With 15 mg/L SWR-NOM: the presence of 100 mg/L bicarbonate increased the total removal of MCPA from 49.1% to 65.1%; the presence of 100 mg/L phosphate increased the total removal of MCPA from 49.1% to 62.5%. With 15 mg/L SWR-NOM, the presence of 100 mg/L bicarbonate increased the total removal of MCPA from 45.2% to 56.1%; the presence of 100 mg/L phosphate increased the total removal of MCPA from 45.2% to 62.9%. The photocurrent measurement support that the presence of such anions greatly suppresses the h + scavenging effect of NOMs; while other anions, i.e. chloride, nitrate, sulfate, showed no notable effect.
关键词： Micropollutant,MCPA,TiO2 nanotube array,Photocatalysis,Natural organic matter
更新于2025-09-23 15:23:52
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Unusual Nano-Microcrystals of Natural Diamond
摘要： Described are unusual nano-microcrystals of natural diamond found in a meteorite crater of Ukraine and advised about the earlier unknown mechanism of diamond polyhedra growth—the formation by globules. It was revealed that diamond nano-microcrystals in a meteorite crater are very similar to globular crystals, and at the same time have octahedral faceting. The morphology and composition of diamond nano-microcrystals are studied by scanning electron microscopy and with an energy dispersive X-ray analyser. These tiny crystals are grown on the grains of impact apographitic diamond from the Bilylivka meteorite crater (Zapadnaya impact crater) on the Ukrainian Shield. Their surface morphology indicates that the nano-microdiamonds are grown, most probably, by a vapor deposition process immediately after the formation of the impact diamond–transformation of the graphite into diamond and lonsdaleite.
关键词： globular polyhedra,growth of crystals,the Ukrainian Shield,nano-microdiamond,natural impact apographitic diamond,morphology,Bilylivka meteorite crater
更新于2025-09-23 15:23:52