Recently, fabricating one-dimensional (1D) nanomaterials on c/ccomposite has been recognized effective to improve the thermal shock resistance of the coated composites. However, the remaining metal catalyst in cVD pr...
详细信息
Recently, fabricating one-dimensional (1D) nanomaterials on c/ccomposite has been recognized effective to improve the thermal shock resistance of the coated composites. However, the remaining metal catalyst in cVD process and the week bond of 1D nanomaterials with substrate limit the strengthening effect. Herein, laser chemical vapor deposition (LcVD) was proposed for fabricating porous Sic nanostructured coating on c/ccomposite without metal catalyst. The laser heating resulted in a temperature gradient between the top and bottom of the coating, providing an external driving force for the vertical growth of whiskers with side-branches, forming a porous network nanostructure. The porous nanostructure was beneficial to reduce cTE and effectively relieve thermal stress. After 10 times of thermal shock test from RT to 1723 K, the porous Sic nanostructured coating remained intact. This work provides a novel methodology to produce functional coating on c/ccomposite with outstanding thermal shock resistance.
A simple set of subroutines in ANSI-c are presented for multiple taper spectrum estimation. The multitaper approach provides an optimal spectrum estimate by minimizing spectral leakage while reducing the variance of t...
详细信息
A simple set of subroutines in ANSI-c are presented for multiple taper spectrum estimation. The multitaper approach provides an optimal spectrum estimate by minimizing spectral leakage while reducing the variance of the estimate by averaging orthogonal eigenspectrum estimates. The orthogonal tapers are Slepian n pi prolate functions used as tapers on the windowed time series. Because the taper functions are orthogonal, combining them to achieve an average spectrum does not introduce spurious correlations as standard smoothed single-taper estimates do. Furthermore, estimates of the degrees of freedom and F-test values at each frequency provide diagnostics for determining levels of confidence in narrow band (single frequency) periodicities. The program provided is portable and has been tested on both Unix and Macintosh systems.
With the increase in application, multi-walled carbon nanotubes (MWcNTs) are potentially bioavailable to environmental organisms. However, the potential transgenerational effect of MWcNTs and underlying mechanisms rem...
详细信息
With the increase in application, multi-walled carbon nanotubes (MWcNTs) are potentially bioavailable to environmental organisms. However, the potential transgenerational effect of MWcNTs and underlying mechanisms remains still unclear. Here, we examined transgenerational MWcNT toxicity and the underlying mechanism mediated by germline long non-coding RNAs (lncRNAs) in caenorhabditis elegans. Exposure to 0.1-10 mu g/L MWcNT caused transgenerational toxicity reflected by endpoints of brood size and locomotion behavior. Meanwhile, among germline lncRNAs, expression of 5 lncRNAs were dysregulated by MWcNT exposure. Among these 5 dysregulated lncRNAs, only germline RNAi of linc-7 affected MWcNT toxicity. Increase in germline linc-7 expression was observed transgenerationally, and transgenerational MWcNT toxicity was prevented in linc-7 (RNAi) nematodes. Moreover, germline linc-7 controlled transgenerational MWcNT toxicity by activating downstream DAF-12, a transcriptional factor. Therefore, our data indicated the association between induction of transgenerational MWcNT toxicity and increase in germline linc-7 expression in organisms.
Superior electrode materials play a key role on the electrochemical performance for the lithium-ion batteries and supercapacitors. The co3O4-based materials are promising electrode materials due to their high specific...
详细信息
Superior electrode materials play a key role on the electrochemical performance for the lithium-ion batteries and supercapacitors. The co3O4-based materials are promising electrode materials due to their high specificcapacity and energy density. However, the poor cycle performance limits their applications during the process of the commercialization for the lithium-ion batteries and supercapacitors. Because of the poor cycle stability, c, N co-doped co3O4 hollow spheres are successfully prepared and used as electrode materials for the lithium-ion batteries and supercapacitors. Via the c, N co-doping process, the electronicconductivity is greatly improved. Moreover, the hollow structure could ensure the structural stability during the electrochemical process. As a result, the cycle performance and specificcapacity are greatly improved when the c, N co-doped co3O4 composites are used as electrode materials for the lithium-ion batteries and supercapacitors. (c) 2019 Hydrogen Energy Publications LLc. Published by Elsevier Ltd. All rights reserved.
The surface adhesion between c. elegans and the agar plates on which they are commonly grown has yet to be accurately quantified. c. elegans is a scientifically important species of nematode whose simple structure all...
详细信息
The surface adhesion between c. elegans and the agar plates on which they are commonly grown has yet to be accurately quantified. c. elegans is a scientifically important species of nematode whose simple structure allowed the first mapping of the complete nervous system in a multicellular organism. One of the current topics of research in the c. elegans community is the investigation of neuronal function in locomotion. Models of locomotion are used in these studies to aid in determination of the functions of specific neurons involved in locomotion. The adhesion force plays a critical role in developing these models. This paper presents the experimental determination of the adhesion energy of a representative sample of c. elegans. Adhesion energy was determined by a direct pull-off technique. In this approach, nematodes are anesthetized to prevent movement and secured to a small load cell before an agar plate is slowly brought into contact with the specimen and then removed. The maximum tensile force is then fit to a JKR-type adhesion model, which assumes that the nematode is a cylinder in order to determine the adhesion energy. Repeated adhesions are also investigated to determine the importance of drying on the measured adhesion force. From these experiments, the adhesion energy was found to be W =4.94 +/- 1.19 mJ/m(2). Limited experiments on the rol-6 cuticle mutant found a lower adhesion energy W =2.65 +/- 1.16 mJ/m(2) for these animals.
Poor intrinsicconductivity has been a principal limiting factor for Na3V2(PO4)3 (NVP) cathode material. Herein, a synergistic strategy of Nb5+ substitution and constructing with three-dimensional rGO lamella is propo...
详细信息
Poor intrinsicconductivity has been a principal limiting factor for Na3V2(PO4)3 (NVP) cathode material. Herein, a synergistic strategy of Nb5+ substitution and constructing with three-dimensional rGO lamella is proposed for the first time to optimize the characteristics of NVP. The introduction of Nb5+ generates beneficial carriers and vacancies that optimize the electronic structure of NVP system. Meanwhile, rGO substrate can construct an effective conductive network for the facilitated electronic transportation and form a stabilized SEI layer after cycling to protect the active particles from being collapsed. This double treatment significantly improves the kineticcharacteristics of NVP. Moreover, theoretical calculations indicate that beneficial Nb5+ doping can effectively reduce the band gap between conductive and valence bands, as well as decline the energy barrier of migration for Na+. Notably, the modified Nb0.15-NVP/c@rGO exhibits impressive electrochemical performance. It delivers a capacity of 107.9 mAh g-1 and keeps a value of 102.6 mAh g-1 after 500 cycles at 2c with a high retention of 95.35%. It submits a capacity value of 97.2 mAh g-1 at 20c, 82.92% reversible capacity (80.6 mAh g-1) could be retained after 2000 cycles. Even at 120 and 300c, this material still performs high values of 84.9 and 71.3 mAh g-1, indicating the superior rate capability.
An interwoven hollow fiber structured mesoporous NiO catalyst doped with c, S was fabricated by the vacuum impregnation and thermal decomposition methods using eggshell membrane as template. The structure of the catal...
详细信息
An interwoven hollow fiber structured mesoporous NiO catalyst doped with c, S was fabricated by the vacuum impregnation and thermal decomposition methods using eggshell membrane as template. The structure of the catalyst was characterized by X-ray diffraction, thermo-gravimetric analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and specific surface area test. Under a high vacuum condition, the synthesized NiO material has a better interwoven fiber and mesoporous structure, which effectively increases the specific surface area of the material. c and S were doped into NiO via eggshell membrane pyrolysis, which then formed c-OH and SO42- species on the surface of the material. The electrocatalytic performance of the catalyst for the oxidation of methanol in alkaline solution was studied by cyclic voltammetry and chronoamperometry. The c, S doped mesoporous NiO material exhibits much higher catalytic efficiency and anti-poisoning ability than that of NiO nanoparticles due to the synergisticcatalysis of NiO and doping c-OH and SO42- species. Graphic abstract
The lack of memory safety in c/c++ often leads to vulnerabilities. code injection attacks exploit these vulnerabilities to gain control over the execution flow of applications. These attacks have played a key role in ...
详细信息
The lack of memory safety in c/c++ often leads to vulnerabilities. code injection attacks exploit these vulnerabilities to gain control over the execution flow of applications. These attacks have played a key role in many major security incidents. consequently, a huge body of research on countermeasures exists. We provide a comprehensive and structured survey of vulnerabilities and countermeasures that operate at runtime. These countermeasures make different trade-offs in terms of performance, effectivity, compatibility, etc., making it hard to evaluate and compare countermeasures in a given context. We define a classification and evaluation framework on the basis of which countermeasures can be assessed.
Silicon (Si) material, with high specificcapacity (4200 mAh/g) and low discharge voltage, is considered as one of the most ideal, promising, and alternative anode materials in next-generation lithium-ion battery (LIB...
详细信息
Silicon (Si) material, with high specificcapacity (4200 mAh/g) and low discharge voltage, is considered as one of the most ideal, promising, and alternative anode materials in next-generation lithium-ion battery (LIBs). In order to resolve the internal drawbacks of Si and reduce the process cost, the Si recycled from the kerf waste of photovoltaic industry was used as raw material. A silane-coupling agent 3-2 (2-sminoethylamino) propyltrimethoxysilane (DAMO) and a binder (PAA) was used to prepare Si@DAMO composite material with cross-linked net structure. Then, the polyvinyl pyrrolidone (PVP) containing N element was coated on the Si@DAMO. After carbonization, the c/Si@DAMO composite material with cross-linked net structure was obtained. The as-prepared c/Si@DAMO anode delivered an initial capacity of around 2841.6 mAh/g, and it remained a reversible capacity of 2066.7 mAh/g after 200 cycles at the current density of 0.1 c. At the rate testing from 0.1 to 1 c, the discharge capacities were 2593.39 mAh/g, 2362.95 mAh/g, 2082.08 mAh/g, 1882.44 mAh/g, 1704.57 mAh/g, and 1545.32 mAh/g, respectively. It retained 2084.88 mAh/g when back to 0.1 ccharge rate after 60 cycles. Therefore, it suggests that the as-prepared c/Si@DAMO is a potential anode material for LIBs.
Aerobiccomposting is an efficient and environmentally friendly method of converting organic waste into nontoxic fertilizers or soil quality enhancers. The quality of the resultant compost depends greatly upon the com...
详细信息
Aerobiccomposting is an efficient and environmentally friendly method of converting organic waste into nontoxic fertilizers or soil quality enhancers. The quality of the resultant compost depends greatly upon the composition of the substrate used. The initial carbon-to-nitrogen (c/N) ratio of the substrate is an important factor affecting the composting process. This study elucidated how initial c/N ratios affect the biodegradation of lignocellulose, due to changes in microbial community structure. Four different c/N ratios (20:1, 25:1, 30:1, and 35:1) were examined during a 35-day composting process. The degradation of cellulose, hemicellulose, and lignin was highest (35.7%, 30.6%, and 19.1% respectively) at a 30:1 c/N ratio;after 30 days, the 25:1 c/N ratio ranked second in terms of lignocellulosic degradation rate. The 30:1 c/N ratio further promoted the growth of functional microorganisms responsible for lignocellulose degradation (Luteimonas, Sphingobium, Trichoderma, chaetomium, and Rosellinia), while the growth of dominant pathogenic microbes (Erwinia and Ulocladium) decreased significantly. These results confirm that the initial c/N ratio of the substrate has a significant effect on the microbial community and degradation of organic matter, during walnut branch composting. This process could therefore offer an alternative means of efficient recycling and recovery of waste branches.
暂无评论