Microstructural characteristics and wear properties of Fe-16Mn-10Al-5Ni-0.86C lightweight steel (LWS) manufactured by laser powder bed fusion (LPBF) process were investigated and compared with conventional LWS. Both LWS alloys constituted an austenite matrix and B2-IMC. The LPBF LWS sample showed polygonal-typed B2-IMC, whereas conventional LWS had rod-typed B2-IMC. The ball-on-disk method was used to perform a wear test at 25°C under three different load conditions of 20N, 3N and 40N. The wear results indicated that the LPBF LWS sample exhibited a similar amount of wear loss under the 20N and 30N load conditions, but it showed better wear resistance under the 40N compared to conventional LWS. After the wear test, the abrasive wear behaviour was confirmed as the main wear mechanism in both LWSs. The formation of oxide layers and debris was analysed through observation of the cross-sectional area of the worn surface.

Aluminum monoxide (AlO) and a nonstoichiometric alumina (n-alumina) with its chemical composition similar to that of AlO were proposed theoretically for a promising low-loss plasmonic material. However, they were rarely studied due to the high thermodynamic instability. Recently, n-aluminas with their O/Al atomic ratios close to 1 were found to form on Al nanospheres synthesized by electrical explosion. Although a new bulk plasmon resonance was observed below the excitonic transition energy from the n-aluminas, no investigation into surface plasmon resonance – the key component for plasmonics - was conducted yet. Here I report on surface plasmons of the n-aluminas discovered by spatially-resolved electron energy loss spectroscopy. Energy loss spectra collected from local spots of the n-aluminas are analyzed to reveal that there are two types of n-aluminas; one with two surface plasmons (n-alumina A) and the other with one surface plasmon (n-alumina B). Remarkably, the oscillator strengths of the novel surface plasmons are as high as that of surface plasmon of Al. The electronic band structure proposed for the n-alumina A shows a lossless energy zone. Consequently, current study demonstrates that the n-aluminas have the potential as a new low-loss plasmonic material.

It has recently been suggested that the extraordinary strain hardening rate in Fe-16Mn-10Al-0.86C-5Ni high specific strength steel [1] is due to the high back stresses arising from the strain incompatibility between austenite matrix and B2-ordered intermetallic second phase [2]. I argue here that the alloy matrix chemistry, particularly short-range ordering of constituent atoms, could be the intrinsic factor that affects the deformation and strain hardening, rather than the stress-strain partitioning caused by the microstructural heterogeneity.

In this study, the authors used cluster-secondary ion mass spectrometry method to investigate the preserved transfer ribonucleic acid (tRNA) encapsulated between two free-standing graphene sheets. Single impacts of 50 keV C602+ projectiles generated the emission of tRNA fragment ions in the transmission direction for mass selection and detection in a time-of-flight mass spectrometer. Ribonucleic acid (RNA) is extremely unstable and prone to rapid enzymatic degradation by ribonucleases. Employing graphene to isolate RNA from the environment, the authors prevent the aforementioned process. Encapsulation was achieved by drop casting a solution of tRNA, prepared using deuterated water, onto one graphene sheet and covering it with another. The event-by-event bombardment/detection mode allowed us to use colocalization analysis method to characterize the tRNA and its immediate environment. The authors found that upon drying, tRNA agglomerated into nanostructures ∼60 nm in diameter via formation and subsequent drying of aqua cells. The tRNA nanoagglomerates had a density of ∼42 structures per μm2 with coverage of ∼12% of the surface area. In addition, trace amounts of water remained mostly around the tRNA nanoagglomerates, probably in the form of hydration.

lloying steel with aluminium improves the material’s strength-to-weight ratio, but the resulting formation of brittle intermetallic compounds within the steel matrix reduces its ductility; here the morphology and distribution of the intermetallic precipitates are controlled to alleviate this problem.

The study of the interaction of hypervelocity nano-particles with a 2D material and ultra-thin targets (single layer graphene, multi-layer graphene, and amorphous carbon foils) has been performed using mass selected gold nano-particles produced from a liquid metal ion source. During these impacts, a large number of atoms are ejected from the graphene, corresponding to a hole of ∼60 nm(2). Additionally, for the first time, secondary ions have been observed simultaneously in both the transmission and reflection direction (with respect to the path of the projectile) from a 2D target. The ejected area is much larger than that predicted by molecular dynamic simulations and a large ionization rate is observed. The mass distribution and characteristics of the emitted secondary ions are presented and offer an insight into the process to produce the large hole observed in the graphene.

Research is conducted to understand relatively unknown electronic behavior of a nanoscale Al/alumina system. This is acquired by a two-step process where characterization by electron microscopy is first performed for crystallography, followed by electron energy loss spectroscopy for electronic response from spatially inequivalent spots of Al nanoparticles with a protective surface oxide. A novel and unique plasmon from the surface oxide is found in the energy loss spectra between 5 and 6 eV other than the previously reported transitions for individual Al and Al2O3. In the current study, various properties of the new transition are sought by evaluating its dependence on crystal structure and particle size along with related physical functions. The results indicate that the novel transition has collective properties, preceded by a single-electron excitation at a slightly lower energy. Application of the Bethe f-sum rule shows that the concentration of charge carriers reaches around the Mott density by the transition. The new excitation is theorized to be involved with a defect energy band which is formed by diffusion in the surface oxide. Another distinctive result is that the excitonic transition typical of an insulator is weak in the surface oxide on Al. This investigation into properties of the Al/alumina system will benefit the applications of Al for plasmonics as well as the study on the nanometer-scale metal/metal oxide interface.

The contents of this paper is to develop a passive sampler for H2S measurement. When the H2S gas exists in the air, AgNO3 solution coated filter of white used phenomenon which is exchanged with black. If the H2S gas concentration increased, the color of AgNO3 solution coated filter is discolored more black. H2S passive sampler measures the H2S gas concentration by changed color of AgNO3 solution coated filter. The reproducibility of the H2S passive sampler is very stable to within an error 5%RSD. The black color of AgNO3 solution coated filter showed a linear relationship with the H2S gas concentrations. In addition, correlation of the developed CDM and CR-10(Minolta, Japan) showed a high correlation to 0.99. Manufactured H2S passive sampler must be kept refrigerated, stability and reactivity was observed for up to 20 days

TiO2 is one of the most promising anode candidates for novel lithium ion batteries which combines the advantage of state of art anode graphite and the safety of Li4Ti5O12. However, the low intrinsic conductivity limits its electrochemical properties. In this paper, a sol-gel based route is presented to produce nanosize TiO2/CNT core-shell composite fibers. Fiber diameter is 253 +/- 63 nm as-spun and 126 +/- 35 nm with subsequent calcination to obtain crystalline phase. Crystallite size is between 13-18 nm. The as-prepared core-shell fibers exhibited similar to 1.5 time higher electronic conductivity, 1.6-3 times greater lithium diffusivity which resulted in 25% more galvanostatic capacity at C/10 compared to bare TiO2 nanofibers. The enhancement in high-rate performance at 10C was over 80% which was crucial for fast charging applications. CNT additives were found to enhance the electronic conductivity, lithium diffusivity and electrochemical properties of the TiO2 nanofibers by both providing an alternative electron and lithium ion conducting mechanism as well as synergistic effects, which were systematically reviewed. (C) 2015 Elsevier Ltd. All rights reserved.