Nanomaterials possess superior optical, electrical, magnetic, mechanical, and thermal properties, which have made them suitable for a multitude of applications. The present review paper deals with ...recent advances in the measurement and modeling of thermophysical properties at the nanoscale (from the solid state to colloids). For this purpose, first, various techniques for the measurement of the solid state properties, including thermal conductivity, thermal diffusivity, and specific heat capacity, are introduced. The main factors that affect the solid state properties are grain size, grain boundaries, surface interactions, doping, and temperature, which are discussed in detail. After that, methods for the measurement and modeling of thermophysical properties of colloids (nanofluids), including thermal conductivity, dynamic viscosity, specific heat capacity, and density, are presented. The main parameters affecting these properties, such as size, shape, and concentration of nanoparticles, aggregation, and sonication time are studied. Furthermore, the properties of not only simple nanofluids but also hybrid nanofluids (which are composed of more than one type of nanoparticles) are investigated. Finally, the main research gaps and challenges are listed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
One of the most fundamental questions in biology is what types of cells form different tissues and organs in a functionally coordinated fashion. Larger-scale single-cell sequencing and ...biology experiment studies are now rapidly opening up new ways to track this question by revealing substantial cell markers for distinguishing different cell types in tissues. Here, we developed the CellMarker database (http://biocc.hrbmu.edu.cn/CellMarker/ or http://bio-bigdata.hrbmu.edu.cn/CellMarker/), aiming to provide a comprehensive and accurate resource of cell markers for various cell types in tissues of human and mouse. By manually curating over 100 000 published papers, 4124 entries including the cell marker information, tissue type, cell type, cancer information and source, were recorded. At last, 13 605 cell markers of 467 cell types in 158 human tissues/sub-tissues and 9148 cell makers of 389 cell types in 81 mouse tissues/sub-tissues were collected and deposited in CellMarker. CellMarker provides a user-friendly interface for browsing, searching and downloading markers of diverse cell types of different tissues. Furthermore, a summarized marker prevalence in each cell type is graphically and intuitively presented through a vivid statistical graph. We believe that CellMarker is a comprehensive and valuable resource for cell researches in precisely identifying and characterizing cells, especially at the single-cell level.
This paper presents a theoretical and experimental study on thermal conductivities of silica aerogel, xonotlite-type calcium silicate and xonotlite–aerogel composite insulation material. The ...transmittance spectra of silica aerogel and xonotlite-type calcium silicate samples are obtained through FTIR measurements. The corresponding extinction coefficient spectra of the three materials are then obtained by applying Beer’s law. The thermal conductivities of aerogel, xonotlite-type calcium silicate, and xonotlite–aerogel composite insulation material are measured from 300 to 970
K and from 0.045
Pa to atmospheric pressure with the transient hot-strip (THS) method. The thermal conductivity models developed for coupled heat transfer of gas and solid based on the unit cell method are compared with the experimental measurement results. It is shown that the effective thermal conductivity models matches well with the experimental data. The specific spectral extinction coefficients of xonotlite-type calcium are larger than 10
m
2
kg
−1, and the specific spectral extinction coefficients of aerogel are larger than 7
m
2
kg
−1 over the whole measured spectra. The density of xonotlite-type calcium silicate is the key factor affecting the effective thermal conductivity of xonotlite–aerogel composite insulation material, and the density of aerogel has little influence. The effective thermal conductivity can be lowered greatly by composite of the two materials at an elevated temperature.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
As a phase change material, erythritol has two main disadvantages: low thermal conductivity and high supercooling degree. In this study, we proposed a novel erythritol/graphene composite phase change ...material, and its thermal properties were predicted by molecular dynamics simulation. The effects of the graphene mass fraction, size and number of layers on the thermal conductivity and phase transition characteristics, including the melting point and supercooling degree, were analyzed. The mechanism behind the above phenomena was revealed from a micro perspective. The results show that graphene can not only improve the thermal conductivity of the composites but also reduce the supercooling degree, thus improving the thermal properties of erythritol. The thermal conductivity of the composites increases with increasing graphene amount, size and number of layers. When the mass fraction of graphene increased to 8 wt%, the thermal conductivity doubled. The melting point of erythritol can be effectively controlled by changing the amount, size and number of layers of graphene. This study can provide guidance for the design and application of erythritol-based composite phase change materials.
Display omitted
•Thermal properties of erythritol/graphene composite were calculated by MD method.•Thermal conductivity of the composite can reach twice of that of pure erythritol.•Graphene can significantly suppress the supercooling degree from 68 °C to 21 °C.•The microscopic mechanism of thermal performance improvement was revealed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Graduation design is the last important link before college students graduate. Referring to the reform and innovation measures of applied talents at home and abroad,this paper analyzes the problems ...and deficiencies of the current graduation design mode of engineering management specialty.Based on the training mode of applied talents,this paper puts forward some measures for graduation design reform and carries them out. Finally, this paper analyzes the achievements and existing problems of the reform.
Anthocyanins are natural water-soluble pigments that are important in plants because they endow a variety of colors to vegetative tissues and reproductive plant organs, mainly ranging from red to ...purple and blue. The colors regulated by anthocyanins give plants different visual effects through different biosynthetic pathways that provide pigmentation for flowers, fruits and seeds to attract pollinators and seed dispersers. The biosynthesis of anthocyanins is genetically determined by structural and regulatory genes. MYB (
avian myeloblastosis viral oncogene homolog) proteins are important transcriptional regulators that play important roles in the regulation of plant secondary metabolism. MYB transcription factors (TFs) occupy a dominant position in the regulatory network of anthocyanin biosynthesis. The TF conserved binding motifs can be combined with other TFs to regulate the enrichment and sedimentation of anthocyanins. In this study, the regulation of anthocyanin biosynthetic mechanisms of MYB-TFs are discussed. The role of the environment in the control of the anthocyanin biosynthesis network is summarized, the complex formation of anthocyanins and the mechanism of environment-induced anthocyanin synthesis are analyzed. Some prospects for MYB-TF to modulate the comprehensive regulation of anthocyanins are put forward, to provide a more relevant basis for further research in this field, and to guide the directed genetic modification of anthocyanins for the improvement of crops for food quality, nutrition and human health.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
We investigate the asymmetric relations between returns and changes in implied moments (i.e., volatility, skewness, and kurtosis) in the crude oil market using the United States Oil (USO) Fund option ...data via a quantile regression model that accounts for investors' heterogeneity. The results show an asymmetric relation between returns and changes in implied moments. With respect to the asymmetric return-volatility and return-kurtosis relation, the impacts of negative returns on changes in implied volatility and kurtosis are stronger than positive returns, especially at the upper quantiles. With respect to the asymmetric return-skewness relation, the impacts of positive returns on changes in implied skewness are more dominant than negative returns, especially at the lower quantiles, and an increase in the contemporaneous positive returns is followed by more implied skewness risk, whereas more negative returns are followed by less implied skewness risk. We argue that the combination of fundamental theories, behavioural theories, investors' heterogeneity theory, and preference higher moments theory support the asymmetric relation between return and implied moments.
•Our work analyzes the asymmetric relationship between return and option implied higher moments in the crude oil market using a quantile regression model.•The impacts of negative returns are stronger for implied volatility and kurtosis, whereas the impacts of positive returns are stronger for implied skewness.•A combination of theoretical explanations including fundamental theories, behavioural theories, investor heterogeneity, and preference high-order moments theory make for a detailed and complex analysis of the three relations.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Microarc oxidation (MAO) is a common surface treatment technology for Mg alloys. The MAO layer, however, often fails to provide long-term protection due to its inherent porosity. Current interests ...are mostly focused on strengthening the corrosion resistance by combining MAO with other film techniques. In this work, we developed a smart protective system characteristic of superhydrophobicity and active self-healing capability on Mg alloy by integrating MAO and electro-assisted sol–gel deposition. The porous MAO precoating could work as both a “shield” and a “reservoir”, respectively, to gain enhanced impedance and sufficient inhibitor loading. The top silica skeletons were responsible for surface superhydrophobicity, used for blocking electrolyte invasion and avoiding premature inhibitor leaching. Using this new system, a highly enhanced corrosion barrier relative to pristine MAO or single superhydrophobic surface was acquired. Furthermore, the self-healing effect of embedded inhibitor was underpinned by in situ scanning vibrating electrode technology. It is expected that the MAO-based duplex coating would further boost the development of functional surfaces for Mg alloy protection.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Nearshore ecosystems are transitional zones, and they may harbor a diverse microbial community capable of degrading azo dyes under extreme environmental conditions. In this study, thirteen bacterial ...strains capable of degrading eight azo dyes were isolated in nearshore environments and characterized using high throughput 16 S rRNA sequencing. The results of this study demonstrate that the biodegradability of azo dyes was influenced by their chemical structure and position of functional groups as well as the type of bacteria. The decolorization rate of Methyl Orange (95%) was double that of the heavier and sterically hindered Reactive Yellow 84 (<40%). Shewanella indica strain ST2, Oceanimonas smirnovii strain ST3, Enterococcus faecalis strain ST5, and Clostridium bufermentans strain ST12 demonstrated potential application in industrial effluent treatment as they were tolerant to a wide range of environmental parameters (pH: 5–9, NaCl: 0–70 g L−1, azo dye concentration: 100–2000 mg L−1) including exposure to metals. Analysis of the transformation products using GC-MS revealed that different bacterial strains may have different biotransformation pathways. This study provides critical insight on the in-situ biotransformation potential of azo dyes in marine environments.
Display omitted
•13 azo dye-degrading bacteria were isolated in coastal and estuarine ecosystems.•Azo dye degradation was influenced by their molecular weight and steric hindrance.•Four bacterial strains were tolerant to a wide range of environmental parameters.•GC-MS revealed that different bacterial strains had different degradation products.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to an outbreak of a pandemic worldwide. For better understanding the viral spike ...(S) protein variations and its potential effects on the interaction with the host immune system and also in vaccine development, the cell epitopes, glycosylation profile and their changes during the global transmission course were characterized and compared with SARS-CoV for their glycosylation profile. We analyzed totally 7,813 sequences screened from 8,897 whole genome sequences on GISAID database up to April 26, and 18 S protein amino acid variations with relatively high frequency (≥10
) were identified. A total of 228 sequences of variants had multiple variations, of note, most of them harboring the D614G mutation. Among the predicted 69 linear B cell epitopes, 175 discontinuous B cell epitopes and 41 cytotoxic T lymphocyte epitopes in the viral S protein, we found that the protein structure and its potential function of some sites changed, such as the linear epitope length shortened and discontinuous epitope disappeared of G476S. In addition, we detected 9 predicted N-glycosylation sites and 3 O-glycosylation sites unique to SARS-CoV-2, but no evidently observed variation of the glycan sites so far. Our findings provided an important snapshot of temporal and geographical distributions on SARS-CoV-2 S protein cell epitopes and glycosylation sites, which would be an essential basis for the selection of vaccine candidates.
PDF
