In this study, a lightweight and robust Ti 3 c 2 T x /carbon nanotubes (cNTs) foam (TcF) was fabricated using Hcl-induced self-assembly, followed by vacuum freeze-drying. The electrical conductivity and mechanical ela...
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In this study, a lightweight and robust Ti 3 c 2 T x /carbon nanotubes (cNTs) foam (TcF) was fabricated using Hcl-induced self-assembly, followed by vacuum freeze-drying. The electrical conductivity and mechanical elasticity of the TcF was higher than those of monolithic Ti 3 c 2 T x foams. This was ascribed to the incorporation of cNTs into Ti 3 c 2 T x preventing the stacking of the Ti 3 c 2 T x nanosheets and producing a well-developed three-dimensional honeycomb-like porous network structure, which considerably improved impedance matching, promoted multiple reflection loss, increased conduction loss and polarisation loss, thus imparting remarkable microwave absorption properties to the TcF. The 1.72 and 1.92 mm thick TcF samples with absorber loadings of 4 wt%, which were obtained by immersing TcF into molten paraffin, followed by cutting it into coaxial rings, presented an optimum reflection loss of −48.8 dB and a maximum effective absorption bandwidth (EAB) of 5.44 GHz, respectively. Moreover, upon increasing the thickness of the TcF samples from 1.52 to 4.92 mm, the EAB could be regulated from 4.16 to 18 GHz, respectively. In this study, we developed a facile method for fabricating a lightweight and robust TcF, which met the ‘light, thin, broad, and strong’ criteria and presented a broad EAB and remarkable dissipation capability, for microwave absorption materials.
To overcome the deficiency of the volume expansion of MoS(2)as the anode material for lithium-ion batteries (LIBs), an effective strategy was developed to design hierarchical porous MoS2/carbon nanospheres via a facil...
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To overcome the deficiency of the volume expansion of MoS(2)as the anode material for lithium-ion batteries (LIBs), an effective strategy was developed to design hierarchical porous MoS2/carbon nanospheres via a facile, easy-operated hydrothermal method followed by annealing. FESEM and TEM images clearly showed that nanospheres are composed of ultra-thin MoS2/c nanosheets coated with carbon layer and possess an expanded interlayer spacing of 0.98 nm. As anodes for LIBs, MoS2/carbon nanospheres deliver an initial discharge capacity of 1307.77 mAh g(-1)at a current density of 0.1 A g(-1). Moreover, a reversible capacity of 612 mAh g(-1)was obtained even at 2 A g(-1)and a capacity retention of 439 mAh g(-1)after 500 cycles at 1 A g(-1). The improved electrochemical performance is ascribed to the hierarchical porous structure as well as the intercalation of carbon into lattice spacing of MoS2, which offers fast channels for ion/electron transport, relieves the influence of volume change and increases electrical conductivity of electrode. Meanwhile, the expanded interlayer spacing of MoS(2)in MoS2/ccan decrease the ion diffusion resistance and alleviate the volumetric expansion during discharge/charge cycles.
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...
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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.
Some studies have assessed the expression of dopaminergic dopamine 2 (D2)/3 receptors in prolactinomas and nonfunctioning pituitary adenomas (NFPA) by positron emission tomography/computed tomography (PET/cT) with
Some studies have assessed the expression of dopaminergic dopamine 2 (D2)/3 receptors in prolactinomas and nonfunctioning pituitary adenomas (NFPA) by positron emission tomography/computed tomography (PET/cT) with
y Recently, approaches based on tree-decompositions (TDs) of control-flow graphs (cFGs) have been introduced for many classical problems in compiler construction. Some found practical use in SDcc, a mainstream ccompi...
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y Recently, approaches based on tree-decompositions (TDs) of control-flow graphs (cFGs) have been introduced for many classical problems in compiler construction. Some found practical use in SDcc, a mainstream ccompiler for embedded systems. Using TD-based algorithms, SDcc generates faster and often smaller code for its target architectures than other compilers. The width of the TD crucially influences runtime, hence good algorithms computing TDs of small width are essential. The current standard approach to obtain TDs of cFGs is Thorup's heuristic, which was also used in SDcc. Thorup claims that his heuristic will give TDs of width at most 6 for cFGs from ccode that contains no goto statements. We present a counter example resulting in a tree-width of 7. We show how to construct ccode without goto statements for which the cFG has tree-width 3, but Thorup's heuristic will yield TDs of arbitrary width. We demonstrate how this flaw adversely affects the compilation of real-world code. We present a constructive proof giving a tight bound on the tree-width of cFGs of c programs. This corrects Thorup and shows the effect that goto has on the tree-width. We empirically evaluate various approaches to finding TDs of cFGs and their impact on compiler runtime and code quality in SDcc. Our research resulted in the replacement of the unconditional use of Thorup's heuristic by a better approach in SDcc 3.7.0, drastically reducing compiler runtime. (c) 2019 Elsevier B.V. All rights reserved.
Abnormal beta-amyloid plaques and tau protein accumulation are the core pathologic features of Alzheimer's disease. However, the accumulation of these proteins is also common in cognitively normal elderly people. ...
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Abnormal beta-amyloid plaques and tau protein accumulation are the core pathologic features of Alzheimer's disease. However, the accumulation of these proteins is also common in cognitively normal elderly people. Therefore, this study is aimed to evaluate the amyloid and tau accumulation in the cognitively normal population. A preliminary prospective study was conducted on 24 cognitively normal individuals who underwent Pittsburgh compound B (
In this paper, co3O4/NiO/ccomposites were prepared by in situ co-precipitation and heat treatment with Zn/co-ZIF-derived N-doped porous carbon as carbon matrix. The structure and constituent of co3O4/NiO/ccomposites...
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In this paper, co3O4/NiO/ccomposites were prepared by in situ co-precipitation and heat treatment with Zn/co-ZIF-derived N-doped porous carbon as carbon matrix. The structure and constituent of co3O4/NiO/ccomposites were detected by the X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and other test methods. The result showed that Nico-LDH nanosheets grew evenly on the surface of porous carbon matrix. co3O4/NiO/ccomposites retained the dodecahedral shape of the carbon matrix. Electrochemical performance was investigated through electrochemical workstation and LAND-cT2001A battery test system. The results showed that the co3O4/NiO/c electrode has a higher initial discharge specificcapacity of 1673.0 mA h g(-1) at 0.1 A g(-1), and it could still maintain the discharge specificcapacity of 1167.8 mA h g(-1) after 100 cycles. The co3O4/NiO/c showed a high reversible capacity of 812.3 mA h g(-1) after 500 cycles at 0.5 A g(-1). The co3O4/NiO/c electrode exhibited excellent lithium storage performance, which can be attributed to the unique functionalities of the ternary components: NiO and co3O4 can guarantee high specificcapacity, while the carbon matrix can improve the conductivity and the stability of the structure. Therefore, co3O4/NiO/ccomposite was expected to be anode material for lithium storage equipment.
In this work, the effects of c, N, and Al on the microstructures and creep properties of Fe-cr-Al-Nb-W ferritic alloys were investigated through scanning electron microscopy, x-ray diffractometry, as well as uniaxial ...
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In this work, the effects of c, N, and Al on the microstructures and creep properties of Fe-cr-Al-Nb-W ferritic alloys were investigated through scanning electron microscopy, x-ray diffractometry, as well as uniaxial creep testing and hardness testing. The results demonstrated that the matrix of the Fe-cr-Al-Nb-W heat-resistant steel was ferrite, while the precipitation phases were Laves phases, M23c6 carbides and MX nitride phases. M23c6 and MX precipitated at grain interior, Laves phases precipitated at grain interior, grain boundary and around MX phases. c, N and Al affected microstructure and creep of heat-resistant steel. As the Al content increased or as N content decreased along with the c increase, the average diameter of the Laves phases, along with M23c6 and MX phase grain interior decrease. Moreover, the unit density increased and the phase spacing decreased, which led to the minimum creep rate decrease and creep rupture time increase. compared to M23c6, Laves and MX phases mainly affected the alloy creep strength. The decrease of Laves phase continuity coefficient (ratio of Laves phase particle spacing and size) on the grain boundary was conducive to the plasticity improvement of heat-resistant steel.
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