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81.
采用快速凝固与脱合金化相结合的方法制备纳米多孔Ni、Ni-Co合金,分别经腐蚀与退火获得纳米多孔NiO、NiCo_2O_4,采用XRD、SEM、TEM、N_2吸附-脱附等对多孔NiO、NiCo_2O_4电极的物相、形貌结构、孔径分布进行表征,并通过循环伏安、恒电流充放电等方法测试多孔电极的电化学性能。结果表明,得到的纳米多孔NiO具有均匀的"泥裂"式结构,在1A·g~(-1)电流密度下比电容为375 F·g~(-1),当电流密度增加至20 A·g~(-1)时的比容保持率为67.5%,在4 A·g~(-1)电流密度下循环充放电1 000次,比容保持率为81.7%;NiCo_2O_4形成典型的开放式纳米多孔双连续结构,其在1A·g~(-1)电流密度下比电容为674 F·g~(-1),当电流密度增加至20 A·g~(-1),比容保持率达72.0%;在4 A·g~(-1)电流密度下循环充放电1 000次,比容保持率达92.9%,双连续纳米多孔结构及其提供的机械稳定性,使得NiCo_2O_4表现出更为优异的超电容性能。 相似文献
82.
Dr. Justine Harmel Dr. Laurent Peres Dr. Marta Estrader Adrien Berliet Dr. Sylvie Maury Dr. Antoine Fécant Dr. Bruno Chaudret Prof. Dr. Philippe Serp Dr. Katerina Soulantica 《Angewandte Chemie (International ed. in English)》2018,57(33):10579-10583
The Fischer–Tropsch synthesis (FTS) is a structure‐sensitive exothermic reaction that enables catalytic transformation of syngas to high quality liquid fuels. Now, monolithic cobalt‐based heterogeneous catalysts were elaborated through a wet chemistry approach that allows control over nanocrystal shape and crystallographic phase, while at the same time enables heat management. Copper and nickel foams have been employed as supports for the epitaxial growth of hcp‐Co nanowires directly from a solution containing a coordination compound of cobalt and stabilizing ligands. The Co/Cufoam catalyst was tested for Fischer–Tropsch synthesis in a fixed‐bed reactor, showing stability and significantly superior activity and selectivity towards C5+ compared to a Co/SiO2‐Al2O3 reference catalyst under the same conditions. 相似文献
83.
Aditya M. Vora 《Central European Journal of Physics》2008,6(2):253-262
The theoretical investigations of the superconducting state parameters (SSP) viz. electron-phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature T
C
, isotope effect exponent α and effective interaction strength N
O
V of six binary La100-C
Ga
C
(C = 16, 20, 22, 24, 26 and 28 at. %) metallic glasses have been reported using Ashcroft’s empty core (EMC) model potential
for the first time. Five local field correction functions proposed by Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid
et al. (F) and Sarkar et al. (S) are used in the present investigation to study the screening influence on the aforesaid properties. It is observed that
the electron-phonon coupling strength λ and the transition temperature T
C
are quite sensitive to the selection of the local field correction functions, whereas the Coulomb pseudopotential μ*, isotope effect exponent α and effective interaction strength N
O
V show weak dependences on the local field correction functions. The T
C
obtained from H-local field correction function are found in qualitative agreement with available experimental data and show
almost linear nature with the concentration (C) of ‘Ga’ element. A linear T
C
equation is proposed by fitting the present outcomes for H-local field correction function, which is in conformity with other
results for the experimental data. Also, the present results are found to be in qualitative agreement with other such earlier
reported data, which confirms the superconducting phase in the metallic glasses.
相似文献
84.
Pd80+x
Si20−x
(x = 0, 1, and 2) binary metallic glasses with the diameter ranging from 7 to 8 mm were prepared by a combination of fluxing
and water quenching or air cooling. Thermal analysis results show that with increasing Si content, the glass transition temperature
T
g, the initial crystallization temperature T
x and the onset crystallization temperature T
p of Pd-Si binary glassy alloys increase. Moreover, the supercooled liquid region reaches 61 K. It indicates that Pd-Si binary
alloys possess large glass forming ability, which can be greatly improved by fluxing treatment.
Supported by the National Basic Research Program of China (Grant No. 2007CB613905) and the National Natural Science Foundation
of China (Grant Nos. 50671050 and 50431030) 相似文献
85.
Koichi KikuchiHiroyuki Nishikawa Isao IkemotoTakashi Toita Hiroki AkutsuShin'ichi Nakatsuji Jun-ichi Yamada 《Journal of solid state chemistry》2002,168(2):503-508
Three FeCl4 salts based on non-tetrathiafulvalene (TTF) donors, 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene (BDH-TTP) and 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP), have been prepared and characterized as κ-(BDH-TTP)2FeCl4, β-(BDA-TTP)2FeCl4, and (BDA-TTP)3FeCl4 · PhCl. The κ-(BDH-TTP)2FeCl4 salt, with a room-temperature conductivity (σrt) of 39 S cm−1, is metallic down to 1.5 K, and its magnetic susceptibility obeys the Curie-Weiss law with a Curie constant (C) of 4.25 emu K mol−1 and a Weiss constant (θ) of 0.041 K. β-(BDA-TTP)2FeCl4 exhibits metallic behavior (σrt=9.4 S cm−1) with a sharp metal-to-insulator (MI) transition (TMI=113 K) and antiferromagnetic ordering with the Néel temperature of near 8.5 K, whereas the solvated (BDA-TTP)3FeCl4 · PhCl salt is a semiconductor with a thermal activation energy of 0.11 eV (σrt=2.0× 10−2 S cm−1) and exhibits Curie-Weiss behavior (C=4.42 emu K mol−1, θ=−0.35 K). 相似文献
86.
This paper reports a comparative study of shear banding in BMGs resulting from thermal softening and free volume creation.
Firstly, the effects of thermal softening and free volume creation on shear instability are discussed. It is known that thermal
softening governs thermal shear banding, hence it is essentially energy related. However, compound free volume creation is
the key factor to the other instability, though void-induced softening seems to be the counterpart of thermal softening. So,
the driving force for shear instability owing to free volume creation is very different from the thermally assisted one. In
particular, long wave perturbations are always unstable owing to compound free volume creation. Therefore, the shear instability
resulting from coupled compound free volume creation and thermal softening may start more like that due to free volume creation.
Also, the compound free volume creation implies a specific and intrinsic characteristic growth time of shear instability.
Finally, the mature shear band width is governed by the corresponding diffusions (thermal or void diffusion) within the band.
As a rough guide, the dimensionless numbers: Thermal softening related number B, Deborah number (denoting the relation of instability growth rate owing to compound free volume and loading time) and Lewis
number (denoting the competition of different diffusions) show us their relative importance of thermal softening and free
volume creation in shear banding. All these results are of particular significance in understanding the mechanism of shear
banding in bulk metallic glasses (BMGs).
Supported by the Chinese Academy of Sciences under the project “Multi-Scale Complex System” (Grant No. KJCX-SW-L08), the National
Natural Science Foundation of China (Grant Nos. 10725211 and 10721202), and the Doctorial Start-up Fund of Hunan University
of Science and Technology (Grant No. E50840) 相似文献
87.
The present study describes an extensive conformational search of substance P using two different computational methods. On the one hand, the peptide was studied using the iterative simulated annealing, and on the other, molecular dynamics simulations at 300 and 400 K. With the former method, the peptide was studied in vacuo with a dielectric constant of 80, whereas using the latter study the peptide was studied in a box of TIP3P water molecules. Analysis of the results obtained using both methodologies was carried out using an in-house methodology using a cluster analysis method based on information theory. Comparison of the two sampling methodologies and the different environment used in the calculations is also analyzed. Finally, the conformational motifs that are characteristic of substance P in a hydrophilic environment are presented and compared with the experimental results available in the literature. 相似文献
88.
Viscosity is an important property that influences industrial processes relevant to fluid. The transferring rate of impurities, such as S, P and N, is affected with the viscosity of metallic melts. The interfacial reactions and impurity removal depend on the viscosity of both slag and metallic melt. Viscosity of gas and liquid are all affecting the transferring process and velocity. However, the amount of viscosity data is far from satisfactory for the needs of today抯 technology, especially… 相似文献
89.
Salvatore Giuffrida Guglielmo G. Condorelli Lucia L. Costanzo Giorgio Ventimiglia Raffaella Lo Nigro Maria Favazza Enrico Votrico Corrado Bongiorno Ignazio L. Fragalà 《Journal of nanoparticle research》2007,9(4):611-619
Liquid Phase Photo-Deposition (LPPD) technique has been used to obtain both colloidal particles and thin films of metallic
and chloride nickel from solutions of only precursor Ni(acac)2 (acac=2,4-pentandionato). Metallic nickel was obtained from ethanol solutions by direct nickel(II) photoreduction at 254 nm
and by acetone sensitised reaction at 300 nm. In this latter process the rate was higher than in the first one. NiCl2 was formed from CCl4 solution by a solvent-initiated reaction. TEM analysis, performed on colloidal particles of nickel, showed that their dimensions
are in the range 2–4 nm. The films did not present carbon contamination and were characterized by AFM, XPS and GIXRD. Metallic
films consisted of particles of 20–40 nm that are the result of the aggregation of smaller crystallites (4–5 nm). Larger agglomerations
(around 200 nm) have been observed for NiCl2 films. 相似文献
90.
抗坏血酸钛对鲢鱼、草鱼、金鱼及泥鳅的毒性都很低,其96h TLm值为1736~10930mg/l。(敏感性顺序:鲢鱼>草鱼>金鱼>泥鳅)抗坏血酸钛对湖螺的48h TLm值与对蟾蜍蝌蚪的96hTLm值分别为12847.2与1886.5mg/l。经皮下注射,抗坏血酸钛对中华大蟾蜍的LD50为2.87g/kg。微核试验表明,钛试 相似文献