34 research outputs found
Thermal properties of carbon black aqueous nanofluids for solar absorption
In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency
Preparation and thermal conductivity of CuO nanofluid via a wet chemical method
In this article, a wet chemical method was developed to prepare stable CuO nanofluids. The influences of synthesis parameters, such as kinds and amounts of copper salts, reaction time, were studied. The thermal conductivities of CuO nanofluids were also investigated. The results showed that different copper salts resulted in different particle morphology. The concentration of copper acetate and reaction time affected the size and shape of clusters of primary nanoparticles. Nanofluids with different microstructures could be obtained by changing the synthesis parameters. The thermal conductivities of CuO nanofluids increased with the increase of particle loading
Genome analysis and in vivo virulence of porcine extraintestinal pathogenic Escherichia coli strain PCN033
Thermal properties of carbon black aqueous nanofluids for solar absorption
<p>Abstract</p> <p>In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.</p
<b>Electrocatalysis of hemoglobin in ionic liquid BMIMPF<sub>6</sub> and CuS nanosphere composite films</b>
Ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF<sub>6</sub>) was mixed homogeneously with nanometer-sized semiconductor CuS sphere to form a new nanocomposite material, which was further used for the immobilization of hemoglobin (Hb) on the surface of carbon paste electrode (CPE). Direct electrochemistry of Hb in BMIMPF<sub>6</sub>-CuS composite film was carefully investigated with a pair of quasi-reversible redox peaks appeared and the formal potential (E<sup>0'</sup>) was got as -135 mV (vs. SCE) in pH 7.0 phosphate buffer solution, which was due to the enhanced direct electron transfer rate of Hb in the biocompatible matrix. The BMIMPF<sub>6</sub>-CuS-Hb/CPE showed excellent electrocatalytic activity to the reduction of hydrogen peroxide with the kinetic parameters for the electrocatalytic reaction evaluated. The results indicated that the BMIMPF<sub>6</sub>-CuS nanocomposite could be used for the preparation of electrochemical biosensor
Whole genome sequence and comparative genome analyses of multi-resistant Staphylococcus warneri GD01 isolated from a diseased pig in China.
Staphylococcus warneri is a coagulase-negative staphylococcus that is a normal inhabitant of the skin. It is also considered to be an opportunistic etiological agent causing significant infections in human and animals. Currently, relatively little attention has been paid to the genome biology of S. warneri pathogenicity and antibiotic resistance, which are emerging issues for this etiological agent with considerably clinical significance. In this study, we determined the complete genome sequence of S. warneri strain GD01 recovered from the sampled muscle abscess tissue of a diseased pig in South China. The genome of S. warneri is composed of a circular chromosome of 2,473,911 base pairs as well as eight plasmid sequences. Genome-wide metabolic reconstruction revealed 82 intact functional modules driving the catabolism of respiration and fermentation for energy production, uptake of distinct sugars as well as two-component regulatory systems. The evidence uncovered herein enables better understanding for metabolic potential and physiological traits of this etiological agent. The antibiotic susceptibility test demonstrated that S. warneri GD01 was resistant to penicillin, amoxicillin, ampicillin, cefalexin, vancomycin, and sulfisoxazole. The associations between antibiotic phenotypes and the related genotypes were identified to reveal the molecular basis conferring resistance to this pathogen. A number of genes coding for potential virulence factors were firstly depicted in the genome of S. warneri GD01, including adhesins, exoenzymes, capsule, and iron acquisition proteins. Our study provides a valuable genomic context of the genes/modules devoting to metabolism, antibiotic resistance, and virulence of S. warneri
All‐Scale Hierarchical Structure Contributing to Ultralow Thermal Conductivity of Zintl Phase CaAg0.2Zn0.4Sb
Abstract TiNiSi‐type Zintl phase CaAgSb can transform into LiGaGe‐type Zintl phase CaAgxZn(1−x)/2Sb when some of the Ag atoms are substituted by Zn atoms, leading to an ultralow thermal conductivity of ≈0.4 W m−1 K−1 in the whole measured temperature range of CaAg0.2Zn0.4Sb. The microstructure is then investigated by spherical aberration‐corrected electron microscopy on an atomic scale, which reveals an all‐scale hierarchical structure that can scatter the phonons in a wide frequency range. There exist a large quantity of CaAgSb nanometer precipitates as well as quite a lot of edge dislocations close to these nanometer precipitates, thus releasing the stress caused by the mismatch between the precipitates and the parent phase. Many twin boundaries also exist around the CaAgSb precipitates. High‐density point defects contain the randomly dispersed Ag vacancies and Zn atoms substituted for the Ag atoms. All these widely distributed multidimensional defects contribute to the decrease of lattice thermal conductivity in a wide temperature range