Search

Detection of a trace amount of NO2 at room temperature has very important applications in air quality monitoring, protection of human health and medical diagnose. However, the existing NO2 sensors often suffer from low sensitivity when the concentration at the ppb-level. Here, we report a new kind of materials based on graphdiyne(GDY) for highly sensitive detection of ppb-level(ppb: part per billion) NO2 at room temperature. After thermal treatment of the as-prepared GDY at 600 °C under argon atmosphere for 2 h(the obtained sample denoted as GDY-600), the prepared sensor with GDY-600 displays excellent sensitivity with a response value of 6.2% towards 250 ppb NO2 at room temperature, which is better than most of reported sensing materials. In addition, the sensor exhibits significantly high selectivity to NO2 against typical interfering gases including CO, CO2, NH3, H2, H2S and toluene. Moreover, the sensor shows remarkable stability after repetitive measurements. The superior sensing performance of GDY-600 can be ascribed to the highly π-conjugated structure with special acetylenic bonds and abundant oxygen-containing functional groups, which are all beneficial for the gas adsorption and redox reaction on the surface.

The Na2UF8 complex is an important intermediate compound in the purification of UF6 by the adsorption–desorption process during fluoride volatility of the spent nuclear fuel, and its decomposition ...

The melting lines of graphite and liquid carbon have been studied for a long time. However, numerous controversies still remain in this field; for instance, different experiments give different melting temperatures. In this work, we explore the melting lines of graphite and graphene by means of classical and ab-initio molecular dynamics. We show that the empirical models developed on the basis of experimental data (AIREBO potential, Tersoff potential and some others) fail to reproduce the properties of liquid carbon properly. The models fitted to ab-initio data (LCBOPII and GAP) give much better results. However, both types of empirical models and ab-initio simulations evidence the presence of smooth structural crossover in liquid carbon. We also show that the “melting” of graphene discussed in previous works on computer simulation is indeed sublimation and propose a novel method to simulate the melting of graphene: simulation of graphene sheet in argon atmosphere. The melting temperature of graphene in argon atmosphere appears to be close to the melting temperature of graphite.

Close to spherical nanosized niobium diboride particles with an average diameter of 65 nm were synthesized by the reaction of amorphous boron with niobium powder at 1073 K in an argon atmosphere in KCl and Na2B4O7 ionic melts (autoclave, argon pressure of 4 MPa, 32 h).

Violet phosphorene, a recently produced elemental 2D material, is a promising electronic and optoelectronic structure. The work function and band alignment of phosphorene nanoflakes are essential for their heterojunction structure design. The work function of violet phosphorene nanoflakes has been shown to decrease with the increase in layers from 5.16 eV to 4.79 eV and tends to be stable on a gold substrate, which has been confirmed via Kelvin probe force microscopy. The work functions measured on a silicon oxide substrate are much higher due to charge accumulation. The experimental work function of few-layer violet phosphorene is different from the intrinsic work function due to substrate doping, while that of thick violet phosphorene nanoflakes approaches the intrinsic work function value. Various functionals have been adopted for the work function calculation of few-layer violet phosphorene and the values obtained have been compared to the experimental results. The band alignments of different layered violet phosphorene materials calculated using the most accurate functional are demonstrated and compared to those of well-known materials to give a practical route for future applications. The work functions of the violet phosphorene nanoflakes have been shown to decrease due to oxidation, but they significantly improve after annealing in an argon atmosphere.

As a star of the MXene materials, 2D titanium carbide (Ti3C2Tx) has attracted broad interest from worldwide researchers in view of its potential application in energy storage, chemical sensing, electromagnetic interference shielding and flexible electronics. In order to further improve performances and satisfy the needs of emerging flexible applications, there is an urgent need to increase the electronic conductivity, environmental stability and flexibility of Ti3C2Tx film. Herein, a two-stage thermal treatment process in an argon atmosphere at low temperature (300 °C) is proposed to address this challenge. The resulting Ti3C2Tx film shows a 16-fold increase in electronic conductivity, while its environmental stability and flexibility are also greatly enhanced. Furthermore, systematic investigation into the microstructure and variations of Ti3C2Tx films before and after thermal treatment shed light on the underlying mechanism, which contributes to a deeper understanding of MXene properties and offers general guidance for improving the performance of MXene films.

A key challenge faced by the chemical industry is to develop some inexpensive and efficient catalysts with defined sites for selective hydrogenation. Herein, carbon-based materials with specific morphology (Bulks, Nanotubes and Nanosheets, respectively) confined Ni (0) and Ni-Nx active sites have been synthesized by using one Nickel-organic framework (Ni-MOF) as the precursor in high-temperature treatments under argon atmosphere (designated as Ni (0)/Ni-N-CBK, Ni (0)/Ni–N-CNT and Ni (0)/Ni–N–CNS, respectively). Interestingly, the key to obtaining a specific morphology of the carbon-based materials is altering the amount of additional nitrogen source (dicyandiamide, DCDA). The catalytic performance towards α, β-unsaturated aldehyde hydrogenolysis demonstrates that the Ni (0)/Ni–N-CNT and Ni (0)/Ni–N–CNS possess superior selective hydrogenation activity and stability, which could be put down to the synergy effect of Ni (0) and single atomic Ni-Nx species.

In this study, hot corrosion behaviours of Haynes 282 (H282), Nimonic 90 (N90), and Haynes HR160 (HR160) in LiCl-Li2O molten salt were investigated at 650 °C under argon atmosphere. The corrosion rate was in the order of H282

The thermal decomposition of post-consumer samples of a carbonated water bottle made of poly(ethylene terephthalate), PC-PET, was examined by linear temperature programing under an argon atmosphere...

An approach for tape casting and sintering of Li7La3Zr1.75Nb0.25Al0.1O12 (LLZNbO) sheets suitable for use in solid-state battery development is described. The use of Li3BO3 as a sintering aid in both pellet and cast tape samples is examined. We find the optimal Li3BO3 content for ionic conductivity in pellets is between 1 and 2 wt% Li3BO3, much less than in prior reports. At this level, ionic conductivity is ~2.5 × 10−4 S cm−1 after sintering in an argon atmosphere at 1000 °C for 6 h. 150–175 micron thick LLZNbO + 0.5% Li3BO3 tapes sintered at 1000 °C for 6 h exhibit ionic conductivity values of 2–3 × 10−4 S cm−1.

A Mo-Si-B coating was prepared on an Nb-Si based alloy by detonation-gun spraying of Mo followed by co-deposition of Si and B via pack cementation. The microstructural evolution and interdiffusion behavior of the coating/substrate system were investigated by annealing for different times at 1250 °C in argon atmosphere. The results show that the interdiffusion zone has a two-layer structure consisting of (Mo, X′)5Si3 (X’ = Nb, Ti, Cr, Hf) and (Nb, X)5Si3 (X = Ti, Cr, Hf), respectively. The growth of the transitional layer, which obeys a parabolic rate law, is dominated by the inward diffusion of Si from the outer layer to the substrate. The interdiffusion coefficients of Si in the transitional layers are calculated using a modified method based on the Boltzmann-Matano analysis.

A novel metal–organic-framework (MOF) composition-tuning strategy has been developed for the synthesis of well-defined hierarchical structures, which is based on reactivity modification of the zeolitic imidazolate framework (ZIF)-67. Typically, 1D ZIF-67@Ni-1,3,5-benzenetricarboxylic acid (ZIF-67@Ni-BTC) nanorods are obtained, which can be easily transformed into 1D graphene-coated NiCo2O4 (NiCo2O4@graphene) nanorods by an annealing treatment in an argon atmosphere, followed by oxidation in ambient air. By controlling the reaction time, novel structures such as hollow ZIF-67@Ni-BTC polyhedra and hollow ZIF-67@Ni-BTC polyhedra/ZIF-67@Ni-BTC nanorods can also be achieved. By virtue of the advantages of the structure and graphene coating, NiCo2O4@graphene nanorods as lithium storage materials exhibit high Li-storage capacity, excellent rate capability and remarkable cycling stability.

Objectives: This study evaluated the effect of argon atmosphere compared with vacuum during porcelain firing on the fracture strength of crowns made of porcelain and electron beam melted (E...

Analysis on the source of CO is very important for prevention of coal spontaneous combustion. In this article, a method of identifying primary CO in coal seams based on an oxygen isotope method is proposed through research. Tests on the oxygen isotopes (δ18O) of CO were generated in coal oxidization reaction and coal pyrolysis reaction. It is found that δ18O of CO will reduce with rising temperature in both reactions, with δ18O of CO being 15–20‰ in air atmosphere and that being 25–28‰ in argon atmosphere in the temperature range of 130–220°C, confirming that the sources of oxygen atoms of CO vary with different atmospheric conditions. Through collecting and testing a number of gas samples from the coal seam and roof in the coal mine, their δ18O of CO is found to be 35.2–37.3‰. The result would improve the prevention of coal spontaneous combustion.

TiB2 nanosheets were synthesized by the borothermal reduction of TiO2 in flowing argon atmosphere with the assistance of MgCl2. Phase transformation was studied by XRD and micromorphology of products was studied by SEM and TEM. In the experiment, the prepared TiB2 formed the nanoscale lamellar structure. These lamellas agglomerated together to be a net-like structure. Effects of reduction temperature, addition of MgCl2, and its amount were discussed in detail. The results indicated that the presence of MgCl2 accelerated the mass transfer of reactant. Moreover, the co-effects of MgCl2 and B2O3 contributed to the formation of TiB2 nanosheets. TiB2 could dissolve in MgCl2 and B2O3 at high temperature and then recrystallized during the cooling process. The products with a specific surface area of 99.32 m2 g−1 were obtained at 1373 K after reacting for 4 h with a MgCl2:TiO2 molar ratio of 1:1.

Domestic detergents are widely used and the detection of detergent residues on tableware is closely related to people's health. As is known to all, it is difficult to sample and measure the residual detergent on tableware. The purpose of this paper is to explore a rapid in situ detergent residues detection method. We have using laser-induced breakdown spectroscopy (LIBS) measured the detergent on porcelain plate. Based on our previous research, we further studied the spectra of detergent in argon atmosphere, and compared them with that in air. We found the spectral characteristics of the cyanogroup (CN) were related to the air around the measuring point. It was indicated that CN could not as previously speculated be used as the LIBS detection feature of detergent. The improvement of signal-to-noise ratio (SNR) in argon environment was proved and we made a study of semi quantitative measurement by the peak height of 330.30 nm in argon atmosphere. An experiment measuring the detergent on tableware after washed was taken. It illustrated that the LIBS technology has promising potential applications for tableware cleaning process or food production process as a means of on-line detection.

Ultrathin graphitic carbon nitride (g-C3N4) nanosheets were synthesized via thermal exfoliation of bulk urea-derived g-C3N4 under an argon atmosphere. As a visible-light responsive photocatalyst, this material exhibits a much superior photocatalytic activity in pollution degradation and H2 evolution than bulk g-C3N4, as a result of the extended region of visible light response and the enhanced surface area of ultrathin g-C3N4 nanosheets. These findings may provide a promising and facile approach to the design of high-performance photocatalysts.

Mixed substituted [Formula: see text]-bromo and cyano Cu(II) porphyrins (CuTPPBr[Formula: see text](CN)[Formula: see text] ([Formula: see text] = 0–4)) were synthesized from CuTPPBr4 by nucleophilic substitution with excess CuCN in quinoline under argon atmosphere for the first time. These porphyrins exhibited a gradual red-shift both in Soret and Q-bands with increase in number of cyano groups. CuTPPBr[Formula: see text](CN)[Formula: see text] ([Formula: see text] 0–4) exhibited anodic shift in their first ring oxidation potential ([Formula: see text] [Formula: see text] = 120–460 mV) and in first reduction potential ([Formula: see text] [Formula: see text] = 450–940 mV) as compared to CuTPP due to electron withdrawing nature of cyano and bromo substituents.

Undoped lithiation of stoichiometric spinel using lithium hydride LiH up to the composition Li2.25Mn2O4 was performed. A homogeneous material with a given Li: Mn ratio was obtained by mechanochemical activation with sequential annealing of a LiMn2O4–LiH mixture in a high-purity argon atmosphere and then in air or oxygen at 373–553 K.

The electrochemical hydrogen storage properties and mechanisms of the Ti 55 V 10 Ni 35 quasicrystal + xLiH(x = 3, 6 and 9 wt.%) system are investigated and discussed in this paper. A composite material in the Ti 55 V 10 Ni 35 quasicrystal and system has been synthesized moderately by means of mechanical milling under an argon atmosphere, which can avoid reaction of releasing of hydrogen during the process of milling. The results indicate that the addition of LiH significantly improves the electrochemical characteristics of composite material. The maximum discharge capacity increases from 220.1 mAh/g to 292.3 mAh/g on Ti 55 V 10 Ni 35 + 6 wt.% LiH, and the cycling stability is also enhanced too. In addition, the high rate dischargeability (HRD) is ameliorated remarkably, and the value of HRD value at 240 mA/g rises by 78.1%–87.8% for Ti 55 V 10 Ni 35 + 6 wt.% LiH alloy electrodes. The improvement of characteristics of the electrochemical hydrogen storage characteristics may be attributed to LiH, which has excellent electrochemical activity.

This manuscript reports on the modulation of the photoreactivity of a series of chromones, also known as benzo-γ-pyrones, by absorption into a porous self-assembled host formed from phenylethynylene bis-urea macrocycles. Chromone and four derivatives namely 6-fluorochromone, 6-bromochromone, 7-hydroxy-4-chromone, and 3-cyanochromone are unreactive in the solid-state. Each of these derivatives was loaded into the nanochannels of self-assembled phenylethynylene bis-urea macrocycles to form solid host·guest complexes, which were subsequently UV-irradiated at room temperature under argon atmosphere. We observed that chromone and 6-fluorochromone underwent selective [2 + 2] photodimerization reactions to produce anti-HT dimers in high selectivity and conversion. The 6-bromochromone also reacted in high selectivity and conversion to afford an aryl coupling adduct. In each case, the products were extracted, and the crystalline host recovered. In comparison, 7-hydroxy-4-chromone, and 3-cyanochromone were unreactive within the complex. Simple GCMC simulation studies suggest that chromone, 6-fluorochromone, and 6-bromochromone were loaded in orientations that facilitate photoreaction, and correctly predicted that the anti-HT dimer would be favored in the chromone case. In contrast, syn-HH dimers were predicted by GCMC simulations for the halogen containing derivatives but were not observed. The simulations with 7-hydroxy-4-chromone were in agreement with the observed reactivity. We compare these computational and experimental findings and suggest future methods for optimizing simulation parameters. Our goal is to expand the scope and accuracy of the simulations to be able to predict the reactivity of guests encapsulated within columnar nanotubes.

This paper reveals that visible light irradiation with Ru(phen)(3)Cl-3 as photocatalyst can induce ethyl 2-(N-arylcarbamoyl)-2-chloroiminoacetates to undergo N Cl cleavage to give alpha-(aminocarbonyl)iminyl radicals under an argon atmosphere. The subsequent cyclization of the thus formed iminyl radicals affords quinoxalin-2(1H)-one products in good yield in the presence of an inorganic base such as Na2CO3. The reactions proceeded very well even without using a photocatalyst when DMF was used as the solvent. These protocols provide a new, simple method for the generation of iminyl radicals, and the reactions described herein constitute an efficient method for the synthesis of quinoxalin-2(1H)-one derivatives.

Cu2SnTe3 nanocrystals with a cubic structure are prepared by reacting stoichiometric amounts of Cu(acac)2 and Ph4Sn in presence of oleylamine (argon atmosphere, 130 °C, 30 min) followed by injection of a TeO2 solution in 1-dodecanethiol (210 °C, 90 min).

Cr2AlC powders were successfully synthesized by molten salt method using Cr, Al and C as starting materials. The effects of the process parameters and amount of Al addition on the purity of the Cr2AlC powders were also investigated in details. The formation mechanism of Cr2AlC powders was investigated by XRD and DSC. The results indicated that intermediates of Cr7C3 and Cr- Al intermetallics, such as CrAl17, Cr2Al, Cr2Al8, were formed by the reactions among the initial elements, then the intermediates gradually transformed to Cr2AlC. From the fixed composition of Cr:Al:C = 2:1.2:1, high purity Cr2AlC powders could be obtained with an inorganic salt KCl as a solvent at 1250 degrees C for 60 min under argon atmosphere which was lower than that (generally 1450 degrees C) of conventional solid state reaction.

An efficient and step-economical ligand-free palladium-catalyzed decarboxylative functionalization of quinolinone-3-carboxylic acids has been well developed. Note that the reaction could proceed smoothly under an argon atmosphere at relatively low temperature by using Pd(OAc)2 as the catalyst and Ag2CO3 as the oxidant. In this protocol, various functionalities were compatible under the reaction condition, and a series of biologically important azaisoflavone derivatives were obtained in moderate to high yields. Azaisoflavone derivatives were obtained in moderate to high yields by ligand-free palladium-catalyzed decarboxylative functionalization of quinolinone-3-carboxylic acid and aryl iodides

We have clarified that the electrical and thermal properties of single-walled carbon nanotubes (SWCNTs) are improved by multiple structural changes (wall number, diameter, and crystallinity) induced by high temperature treatment. Focusing on the relationship between structural change and electrical and thermal properties, high-purity SWCNTs were fabricated using the water-assisted CVD method and treated at high temperatures (1500–2000 °C) in an argon atmosphere. We showed that the electrical and thermal properties of the SWCNTs were improved by ∼2.9 and 3.0, respectively, which required lower treatment temperatures than for multi-walled CNTs (MWCNTs). In addition to the crystallinity improvement, the wall number and diameter increased with treatment temperature. When compared to as-grown SWCNTs of similar wall number and diameter, the heat treated SWCNTs exhibited higher electrical and thermal properties, which suggested that the property improvements could be attributed to not only to the wall number and diameter but also to the improvement in crystallinity.

Chemistry - a European journal 24(55), 14679 - 14685 (2018). doi:10.1002/chem.201803235, The new ternary transition metal borides Mn$_{3‐x}$Ir$_5$B$_{2+x}$ (0≤x≤0.5) and Mn$_2$IrB$_2$ were synthesized from the elements under high temperature and high‐pressure/high‐temperature conditions. Both phases can be synthesized as powder samples in a radio‐frequency furnace in argon atmosphere. High‐pressure/high‐temperature conditions were used to grow single‐crystals. The phases represent the first ternary compounds within the system Mn–Ir–B. Mn$_{3−x}$Ir$_5$B$_{2+x}$ (0≤x≤0.5) crystallizes in the Ti$_3$Co$_5$B$_2$ structure type (P4/mbm; no. 127) with parameters a=9.332(1), c=2.896(2) Å, and Z=2. Mn$_2$IrB$_2$ crystallizes in the β‐Cr$_2$IrB$_2$ crystal structure type (Cmcm; no. 63) with parameters a=3.135(3), b=9.859(5), c=13.220(3) Å, and Z=8. The compositions of both compounds were confirmed by EDX measurements and the compressibility was determined experimentally for Mn$_{3−x}$Ir$_5$B$_{2+x}$ and by DFT calculations for Mn$_2$IrB$_2$., Published by Wiley-VCH, Weinheim

Dedicated to Professor Ernesto Carmona on the occasion of his 70th birthday., The X-ray study on a single crystal of the butterfly-like complex [{Pt(C^C*)(μ-pz)}2 ] (1), containing a cyclometalated N-heterocyclic carbene ligand as wings (HC^C*=1-(4-(ethoxycarbonyl)phenyl)-3-methyl-1H-imidazol-2-ylidene), showed three molecules in the asymmetric unit with intermetallic separations (Å) of 3.2294(4) (1A), 3.2834(4) (1B), and 3.1208(6) (1C). From the reaction of 1 with excess of CHI3 in the air and the sunlight, complex [{Pt(C^C*)(μ-pz)I)}2 ] (2) (dPt-Pt =2.6079(2) Å) was obtained as the major product, while [IPt(C^C*)(μ-pz)2 Pt(C^C*)CHI2 ] (3) (dPt-Pt =2.6324(3) Å) was obtained as the major product under argon atmosphere in the dark. Experimental and theoretical investigations showed that an easily accessible radical-like mechanism operates under thermal conditions, with dioxygen acting as an efficient radical (R. ) scavenger. The oxidation of a Pt2 (II,II) "butterfly" by CHI3 to give metal-metal bonded Pt2 (III,III) compounds is described now for the first time., This work was supported by the Spanish Ministerio de Economía y Competitividad (MINECO)/FEDER (Project CTQ2015-67461-P led by Dr. Babil Menjjn) and by the Gobierno de Aragón and Fondo Social Europeo (Grupo E17_17R: Química Inorgánica y de los Compuestos Organometálicos led by Dr. José M. Casas).

In this work, N-doped graphene (NG) has been synthesized successfully by calcination of dicyandiamide and glucose mixture in an argon atmosphere. The photoluminescence properties of NG were studied systematically. The results show that N-doping can quench its fluorescence and the quenching efficiency depends on the graphitic N content.

Photocatalytic reduction of 25 μmol 2,2'-dinitrobiphenyl in 50% aqueous iso-propanol and 50 mg P25-TiO2 under an argon atmosphere and 20 h UV light irradiation selectively produced 23.8 μmol of benzo[c]cinnoline (95%), and 2,2'-biphenyldiamine (5%) whose amount gradually increased with the irradiation time beyond 20-24 h due to further reduction of benzo[c]cinnoline.

A novel ether/BF3 reductive system has been described, in which diphenylmethanols and their ether and ester derivatives are used as starting materials. Reductions are performed in ether under reflux and an argon atmosphere, and the addition of extra water is beneficial to this reduction. A series of alkanes are able to be prepared with good to excellent yields. A deuterated experiment exhibits that the reductive hydrogen is generated from ether. The mechanism is discussed in detail to explain the observed reactivity.

Single crystals of multifunctional Ca0.9Nd0.1Ti0.9Al0.1O3 have been grown in air and also in argon atmosphere using an optical floating zone technique. The phase composition of the grown single crystals was verified by a powder X-ray diffraction technique. The quality of the grown single crystals was ascertained by rocking curves and Laue patterns. Raman spectra showed the disordering in the B cation site due to the valence mismatch between Ti4+ and Al3+. The energy levels of Nd3+ in the CaTiO3 matrix were determined using the absorption and emission spectra. An absorption band at 806 nm and a strong emission band at 1064.48 nm show that the crystals have good laser optical quality for diode-laser pumping.

Arc melting with nonconsumable tungsten electrode and water-cooled copper crucible was used to fabricate Ti–Cu binary alloys with different Cu contents in an argon atmosphere. The compositions and phase structures of the fabricated alloys were investigated by glow discharge optical emission spectroscopy (GDOES) and X-ray diffraction (XRD). Nanoindentation tests through continuous stiffness measurement were then performed at room temperature to analyze the mechanical behaviors of the alloys. Results indicated that the composition of each Ti–Cu binary alloy was Ti(100−x) Cu x (x = 43, 60, 69, and 74 at.%). The XRD analysis results showed that the alloys were composed of different phases, indicating that different Cu contents led to the variations in alloy hardness. The wear tests results revealed that elemental Cu positively affects the wear resistance properties of the Ti–Cu alloys. Nanoindentation testing results showed that the moduli of the Ti–Cu alloys were minimally changed at increasing Cu content, whereas their hardness evidently increased according to the wear test results.

With rapid growth in the use of NdFeB magnets and growing concerns for environmental protection as well as conservation of rare earths (REs), the recycling of NdFeB magnet scrap is becoming a hot issue for current society. In this study, it is demonstrated that the rare earths in a NdFeB magnet can be selectively extracted using molten MgCl2–KCl salts at temperatures of 600–1200 °C. After crushing to granules, the scrap was subjected to molten chlorides in a dry argon atmosphere. The reaction process between NdFeB scrap and molten MgCl2–KCl was directly observed using a high-temperature contact angle measuring instrument to clarify the phenomena that occur when rare earth chlorides are formed in situ. Furthermore, the effects of reaction temperature, holding time, and mass ratio of MgCl2/NdFeB were investigated to transform REs in the scrap to RECl3 as completely as possible. The reaction products were examined with the necessary analytical techniques including SEM, EDS, XRD, and ICP. The overall extracti...

In order to improve interfacial bonding strength between carbon nanofibers (CNFs) and SiC matrix in CNFs/SiC composites and to disperse CNFs uniformly in the matrix, SiC coating on surface of CNFs was performed in argon atmosphere in the temperature range of 1400 to 1800°C using SiO2, SiO, and mixture of Si and SiO2 powders (Si/SiO2 powder) as silicon sources, and the modification and dispersibility of the treated CNFs were investigated. β-SiC particles were deposited on the surface of the CNFs in all the specimens at 1600–1800°C. So more SiC was formed by heating CNFs with SiO powder at 1600°C. However, the formed SiC was oxidized at higher temperature, practically, at 1800°C. This oxidation was advanced more by using SiO2 and Si/SiO2 powders as silicon sources and very fine carbon fibers were observed on the surface of CNFs. The dispersibilities of CNFs heated with Si/SiO2 and SiO powders were superior to those of as-received CNFs, CNFs treated with NaClO3 solution and CNFs heated with SiO2 powder, which resulted from the advanced oxidation of CNFs and the silanol group (–SiOH) on surface of formed SiC., Article, J. Ceram. Soc. Jpn. 122(1429):822-828 (2014)

Die direkte Feststoff-Multielementanalytik von Kohle und deren Konversionsprodukten mittels elektrothermischer Verdampfung in Verbindung mit einem Atomemissionsspektrometer mit induktiv gekoppeltem Plasma (ETV-ICP OES) wird am Beispiel der Schwefelbestimmung dargestellt. Zusatzlich zur Gesamtgehaltsbestimmung ist eine Aussage uber das Freisetzungsverhalten des Schwefels, basierend auf der kontrollierten thermischen Zersetzung der Probe in Argonatmosphare und unter Normaldruck moglich. Dies konnte die Grundlage fur eine temperaturabhangige Schwefelspeziation darstellen. The direct solid sample multielemental analysis of coal and its conversion products by electrothermal vaporization inductively coupled plasma optical emission spectrometry (ETV–ICP OES) is presented for analyzing sulfur. In addition to the determination of the total content, it is possible to keep track of the release of sulfur, based on controlled thermal decomposition of the sample in argon atmosphere and under ambient pressure. This could be fundamental for a possible speciation of sulfur in coal.

The mechanochemical milling was utilized to control the nanostructures of plate-like graphite (Gp) microparticles in an argon atmosphere and at room temperature. The aggregated Gp nanoparticles were prepared by the simple solid-state process without organic solvent. Electron microscope observations, X-ray diffraction patterns and Raman spectra revealed the fractured plate-like Gp microparticles as well as the Gp microparticles agglomerated to each other through the dissociative edge surfaces by the milling process to finally generate the Gp nanoparticle aggregates. In the process, the ratio of the edge plane surfaces with the dangling bondings to layered internal surfaces clearly increased with the milling. Therefore, the low environmental burden process for preparing the Gp nanoparticle aggregation was achieved.

RE 11 Pd 4 In 9 compounds ( RE = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy) were synthesized by arc-melting of pure metals under an argon atmosphere with subsequent annealing at 870 K and characterized by X-ray powder diffraction. They belong to the Nd 11 Pd 4 In 9 structure type (space group Cmmm , Z = 2) with the following lattice constants: a = 15.581(5), b = 22.606(8), c = 3.767(1) A for La 11 Pd 4 In 9 ; a = 15.431(6), b = 22.516(9), c = 3.763(2) A for Ce 11 Pd 4 In 9 ; a = 14.883(3), b = 22.319(4), c = 3.736(1) A for Pr 11 Pd 4 In 9 ; a = 14.825(6), b = 22.269(8), c = 3.779(1) A for Nd 11 Pd 4 In 9 ; a = 14.706(2), b = 22.094(3), c = 3.729(1) A for Sm 11 Pd 4 In 9 ; a = 14.701(3), b = 22.046(5), c = 3.722(8) A for Gd 11 Pd 4 In 9 ; a = 14.614(5), b = 21.985(3), c = 3.679(2) A for Tb 11 Pd 4 In 9 , a = 14.606(4), b = 21.896(6), c = 3.626(9) A for Dy 11 Pd 4 In 9 . The structure is a member of the homological series RE m + n M 2 n X m based on AlB 2 ( m ) and CsCl ( n ) types.

In-situ 20 wt.%Al2O3/Fe–25Al composites were prepared by mechanical alloying (MA) inducing self-propagating reaction (SHS) with subsequent plasma activated sintering (PAS). The density and hardness of the composites were 99.2% and 56.9 HRC, respectively. The tribological properties of 20 wt.%Al2O3/Fe–25Al composites under dry sliding against GCr15 bearing steels from room temperature to 773 K in argon atmosphere were investigated. The results show that the friction coefficients of 20 wt.%Al2O3/Fe–25Al composites are in the range of 0.47–0.88 at the given testing conditions, and they decrease with increasing temperature at first, then increase again at 773 K. Similarly, the wear rates of Al2O3/Fe–25Al composites are much lower than that of Fe–25Al alloys. The wear rates of the composites are higher at room temperature but dramatically decrease with increasing temperature. At 773 K, the wear rates of the composites and the counterpart GCr15 bearing steel disk are on the order of 0.03 (10−3 mm3/Nm). The dominant wear mechanism of 20 wt.%Al2O3/Fe–25Al composites is microploughing with a little oxidation wear and adhesive wear at room temperature. The main wear mechanism is transferred to adhesive wear with increasing temperature, especially at 773 K, the wear mechanism is mainly adhesive wear.

The novel compound Ce2Ru2Ga3 was synthesized by arc-melting the elemental constituents in argon atmosphere followed by long-term annealing at 873 K. It forms in an orthorhombic system, with a crystal structure of new type (space group P212121, Z ¼ 4, oP28) and the lattice parameters: a ¼ 4.488(2) A, b ¼ 6.912(4) A, c ¼ 17.092(9) A. The gallide is structurally related to intermetallics crystallizing with the NdRh2Sn4-type structure or its derivatives. It represents an unique family of materials with abnormally

Epitaxial graphene growth was performed on the Si-terminated face of 4H-, 6H-, and 3C-SiC substrates by silicon sublimation from SiC in argon atmosphere at a temperature of 2000 degrees C. Graphene ...

This paper presents the results of a study of the chemical composition, depth profile analyses of pulsed laser deposited CaS:Eu2+ thin films grown at different substrate temperatures. Using Auger electron spectroscopy, we have shown that the thin film grown in an argon atmosphere shows sulfur deficiency as the substrate temperature is increased from 200 to 650 °C.

Large-scale SiC nanowires were prepared by directly annealing polysiloxane and wood powder composites without catalyst assistant at 1420 °C under argon atmosphere. SiC nanowires are up to tens of micrometers in length and the diameters are in the range of 30–150 nm. Most nanowires are smooth and straight in morphology. High-resolution TEM image shows that SiC nanowires grow along the [111] direction. The vapor–solid mechanism was proposed to explain the growth procedure of SiC nanowires. The present work provides an efficient and simple strategy for large-scale production of SiC nanowires.

Needle-shaped silvery single crystals of the title compound are synthesized by arc-melting of the elements under argon atmosphere.

Allylic oxidation of cycloolefins was carried out over Ag-VPO catalyst using tert-butyl hydroperoxide (TBHP) as oxidant in argon atmosphere, under our reaction conditions, attack of the activated C–H bonds was preferred instead of the epoxidation of C=C bond and corresponding α, β-enones were obtained as the main products. It is a high yielding, safe and eco-friendly method.

Ti–49Al (at.%) alloy was directionally solidified in Bridgman-type directional solidification furnace. The specimens were directionally solidified under an argon atmosphere with the different growth rate (V=5–30 μm/s) at a constant temperature gradient (G=12.1 K/mm), and with the different temperature gradient (G=2.8–12.1 K/mm) at a constant growth rate (V=10 μm/s). The dendritic spacings (λ 1) were measured from both transverse and longitudinal sections of the specimens. The dependence of λ 1 on the growth rate (V) and temperature gradient (G) were determined by using linear regression analysis. According to the experimental results, the value of λ 1 decreases with the increase of values of V and G. The experimental results were compared with the current theoretical and numerical models, and similar previous experimental results.

The boron trifluoride induced Suzuki-Miyaura cross-coupling of aryltriazenes with arylboronic acids catalyzed by Pd(OAc)2 without added ligands has been achieved for the first time. The reactions performed at room temperature under an argon atmosphere give biaryls in good to excellent yields. It is noteworthy that the reactions were conducted under mild and ligand-free conditions.

Hydrogen storage alloys (LaGdMg)Ni 3.35- x Co x Al 0.15 ( x =0, 0.1, 0.3, 0.5, 1.0, 1.5, 2.0) were prepared by induction melting followed by annealing treatment in argon atmosphere. The effects of partly replacing Ni by Co element in (LaGdMg)Ni 3.35 Al 0.15 on the phase structure and electrochemical properties of (LaGdMg)Ni 3.35- x Co x Al 0.15 alloys were investigated. Structure analysis showed that the alloys consisted of Ce 2 Ni 7 -type (Gd 2 Co 7 -type), CaCu 5 -type, Pr 5 Co 19 -type, PuNi 3 -type phase structure. The addition of Co element obviously reduced the contents of CaCu 5 -type phase and increased the contents of Ce 2 Ni 7 -type phase. However, Pr 5 Co 19 -type and CaCu 5 -type phase obviously increased with the high content of Co. Rietveld analysis showed that the c-axis lattice parameters and cell volumes of the component phases increased with increasing Co content. The electrochemical measurements showed that as the Co content increased, the maximum discharge capacity and the cyclic stability of the annealed alloys both first increased then decreased. The (LaGdMg)Ni 3.05 Co 0.3 Al 0.15 alloy electrode exhibited the maximum discharge capacity (392.92 mAh/g), and the (LaGdMg)Ni 1.85 Co 1.0 Al 0.15 alloy electrode showed the best cyclic stability ( S 100 =96.1%).

We have measured the standard potential of the system Np(III)/Np(o) in the molten LiCl—KCl eutectic. The cell used has been the following: The work was carried out in glove-boxes under a pure argon atmosphere. A comparison has been made with previous standard potentials determinations of uranium and neptunium in the same eutectic.

Series of RE11Ni4In9 compounds (RE = La, Ce, Pr, Nd, Sm, Gd, Tb, Y) were obtained by arc-melting of metals under an argon atmosphere. Their crystal structure was determined from X-ray powder data (STOE diffractometer, CuKα1-radiation) and belongs to the Nd11Pd4In9 structure type (space group Cmmm, Z = 2), which is the member of homological series based on AlB2 and CsCl types. Lattice constants: a = 15.0173(9), b = 22.515(2), c = 3.8381(1) A for La11Ni4In9; a = 14.8506(7), b = 22.222(1), c = 3.7797(1) A for Ce11Ni4In9; a = 14.791(1), b = 22.164(2), c = 3.7542(1) A for Pr11Ni4In9; a = 14.7288(8), b = 22.084(1), c = 3.7324(1) A for Nd11Ni4In9; a = 14.600(1), b = 21.903(2), c = 3.6880(2) A for Sm11Ni4In9; a = 14.4802(6), b = 21.7597(9), c = 3.6575(1) A for Gd11Ni4In9; a = 14.4060(7), b = 21.639(1), c = 3.6284(1) A for Tb11Ni4In9; a = 14.327(4), b = 21.497(6), c = 3.6070(9) for Y11NI4In9.