Effect of heat treatment of Mn-Cu precursors on morphology of dealloyed nanoporous copper

Nanoporous copper with nano-scale pore size was synthesized by dealloying Mn-Cu precursor alloy using a free corrosion method. The effects of heat treatment of Mn-Cu precursors on alloy phase, morphology and composition of the resultant nanoporous copper were investigated. It is revealed that the compositions distribute homogeneously in the bulk Mn-Cu precursors, which consequently results in a more fully dealloying for forming nanoporous copper. The alloy phase changes from Cuo.a9Mno.51 and Cuo.21Mno.79 of non-thermally treated precursor to Cuo.33Mn0.67 of heat treated alloy. The residual Mn content in nanoporous copper is decreased from 12.97% to 2.04% （molar fraction） made from the precursor without and with 95 h heat treatment. The typical pore shape of nanoporous copper prepared by dealloying the precursor without the heat treatment is divided into two different zones： the uniform bi-continuous structure zone and the blurry or no pore structure zone. Nanoporous copper is of a uniform sponge-like morphology made from the heat-treated precursor, and the average ligament diameter is 40 nm, far smaller than that from the non-thermally treated precursor, in which the average ligament diameter is estimated to be about 70 nm.

Synthesis and characterization of single-phase nanocrystalline Ag_2Al particles

Single-phase Ag2Al intermetallic nanoparticles, and Ag and Al metallic nanoparticles were synthesized by the flow-levitation （FL） method. Measurements of d-spacings from X-ray diffraction and electron diffraction confirmed that the intermetallic nanoparticles had the hexagonal Ag2Al structure. The morphology, crystal structure and chemical composition of Ag2Al nanoparticles were investigated by transmission electron microscopy, X-ray diffraction and induction-coupled plasma spectroscopy. A thin amorphous coating was formed around the particles when exposed to air. Based on the XPS measurements, the surface coating of the Ag2Al nanoparticles could most likely be aluminum oxide or silver aluminum oxide. Therefore, the single-phase nanocrystalline Ag2Al intermetallic compound particles can be produced by adjusting some experimental parameters in FL method.

Ionic Charge State Distribution of Au Plasma for 7-Ion System

The present work extends the previous work^[2] on 5-ion system to consider 7-ion system （i.e., Au^47＋ -Au^53＋）. It is found that more highly charged ions, e.g., Au^53＋, Au^54＋ etc., could be able to be neglected, however, less highly charged ions, e.g., Au^47＋, Au^46＋ etc., are rather important. Therefore, a new idea to consider 8-ion system, i.e., Au^46＋ - Au^53＋, is under way. As a supplement, we discuss the simultaneous reaction, which would be important in this sort of works.

Effects of Laser Parameters on Fast Electron Generation in a Multihole Array Target

The effects of laser parameters on the production of fast electrons from laser-multihole array target interaction are investigated theoretically via two-dimensional particle-in-cell simulations.The results show that the fast electron temperature is scaled by I^(1/2)(λ)^(2)with I and(λ)being the laser intensity and wavelength.When the laser intensity reaches 2.14×10^(20)W.cm^(-2),a typical bi-Maxwellian energy distribution is observed.The slope temperature of the low-energy component fits the linear scaling T_(h)~I^(1/2)well.The high-energy component has an increased slope temperature comparable to ponderomotive potential scaling law.In addition,the electron temperature rises linearly with the pulse duration,T_(h)~△_(t).The divergence angle of the fast electrons increases with laser intensity and pulse duration,but is independent of laser wavelength.

Density Functional Theory and Grand Canonical Monte Carlo Simulations of the Hydrogen Storage Properties of Partially Truncated and Open Cage C60 Fullerenes

The potential energies of H2 molecules with partially truncated and open cage C_(60) fullerenes,including C_(58),C_(55),C_(54)(I),C54(II)and C_(46),are investigated by means of the density functional theory method.The energy barrier for one H2 molecule(with two postures)entering into the nanocage decreases from 435.59(513.45)kcal/mol to 3.64(¡2.06)kcal/mol with the increase of the truncated pore.The grand canonical Monte Carlo simulations reveal that each nanocage can accommodate only one H_(2) molecule inside its cavity at both 77K and 298 K.All the other H2 molecules are adsorbed round the truncated pores outside the nanocages.Exceptionally,the truncated C_(46) can store 2.28wt%H2 molecules at 77 K.Therefore,the truncating part of the C60 molecule may be a novel idea to explore C_(60) fullerene as a hydrogen storage material.

Ion-implanted Mechanism of the Deposition Process for Diamond-Like Carbon Films

Due to the local densification, high-energy C and doped ions can greatly affect the bonding configurations of diamond-like carbon films. We investigate the corresponding affection of different incident ions with energy from 10eV to 600eV by Monte Carlo methods. The ion-implanted mechanism called the subplantation （for C, N, O, W, Y, etc.） is confirmed. Obvious thermal effect could be induced by the subplantation of the incident ions. Further, the subplantation of C ions is proved by in situ reflection high energy electron diffraction （RHEED）. The observation from an atomic force microscope （AFM） indicates that the initial implantation of C ions might result in the final primitive-cell-like morphology of the smooth film （in an area of 1.2 mm× 0.9 mm, rms roughness smaller than 20 nm by Wyko）.