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The effects of extruded corn flour (ECF) on the rheological properties of the wheat‐based composite dough and quality of the bread were investigated. The RVA results of the composite flour with ECF showed weak thermal viscosity and resistance to starch retrogradation. Mixolab tests revealed that the water absorption capacity increased with the increasing amount of ECF, while dough development time (DT) and dough stability (ST) showed a downward trend, and the composite dough became more resistant to retrogradation. The microstructure of the composite dough showed that the presence of both ECF and unextruded corn flour (UECF) resulted in a more broken gluten matrix. The breads made from the composite flour with ECF had significantly softer texture, lower hardening percentage with storage time, darker crust color, larger specific volume, and higher sensory scores than the UECF ones. It is concluded that the extrusion of corn flour is an effective way to improve the quality of the composite bread and retard staling during storage.

Electron-enhanced atomic layer deposition (EE-ALD) was used to deposit boron nitride (BN) thin films at room temperature and 100 °C using sequential exposures of borazine (B(3)N(3)H(6)) and electrons. Electron-stimulated desorption (ESD) of hydrogen surface species and the corresponding creation of reactive dangling bonds are believed to facilitate borazine adsorption and reduce the temperature required for BN film deposition. In situ ellipsometry measurements showed that the BN film thickness increased linearly versus the number of EE-ALD cycles at room temperature. Maximum growth rates of ~3.2 Å/cycle were measured at electron energies of 80–160 eV. BN film growth was self-limiting versus borazine and electron exposures, as expected for an ALD process. The calculated average hydrogen ESD cross section was σ = 4.2 × 10(−17) cm(2). Ex situ spectroscopic ellipsometry measurements across the ~1 cm(2) area of the BN film defined by the electron beam displayed good uniformity in thickness. Ex situ X-ray photoelectron spectroscopy and in situ Auger spectroscopy revealed high purity, slightly boron-rich BN films with C and O impurity levels

The surface chemistry associated with the atomic layer deposition (ALD) of platinum films on metallic nickel substrates using trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtMe3) and oxygen was characterized by using X-ray photoelectron spectroscopy (XPS). The uptake of the MeCpPtMe3 ALD precursor was found to be self-limiting between 525 and 625 K, but to lead to multilayer deposition at 675 K. The adsorbed species display a C:Pt ratio of approximately 5:1, suggesting that all methyl moieties are lost upon activated bonding to the surface but that the methylcyclopentadienyl group remains coordinated to the adsorbed Pt atoms. Oxygen treatment of that surface leads to the complete removal of the carbon-containing species from the surface and to the formation of a thin NiO film. Further dosing with MeCpPtMe3, in the next ALD cycle, fully reduces that NiO film to metallic Ni(0) and adds more Pt to the surface. However, no Pt film buildup was seen after several ALD cycles. Angle-resolved XPS data suggested that the deposited Pt migrates below the NiO that forms during the O2 exposures and possibly alloys with the metallic Ni substrate at that stage.

Physicochemical properties of common buckwheat flour processed using a high-speed universal grinder (UGBF), wet-milling (WMBF) and a stone mill (SMBF) were investigated and compared, since there is scarce information concerning the effect of different milling methods on physicochemical properties of common buckwheat flour. The results showed that WMBF had lower average particle size and damaged starch content than other samples. Scanning electron microscopy (SEM) observations showed that WMBF had more intact granular structures compared to UGBF and SMBF. The bulk densities of UGBF and SMBF increased as the particle size decreased, whereas WMBF exhibited a reverse trend according to bulk density analysis. Wet-milling method caused a significant lowering of the total flavonoid content. Colour measurements revealed that WMBF exhibited higher L* value compared to other samples. Differential scanning calorimeter (DSC) analysis showed that WMBF had significantly lower Tp but higher ΔH compared to UGBF and SMBF. Rapid Visco Analyzer (RVA) measurements showed that the suspension viscosity of SMBF and WMBF was higher than UGBF. Furthermore, among different buckwheat flour, WMBF showed the highest water absorption index (WAI) value and swelling power (SP) value but the lowest water solubility index (WSI) value and water binding capacity (WBC) value.

Electron-enhanced atomic layer deposition (EE-ALD) was used to deposit boron nitride (BN) thin films at room temperature and 100 °C using sequential exposures of borazine (B3N3H6) and electrons. Electron-stimulated desorption (ESD) of hydrogen surface species and the corresponding creation of reactive dangling bonds are believed to facilitate borazine adsorption and reduce the temperature required for BN film deposition. In situ ellipsometry measurements showed that the BN film thickness increased linearly versus the number of EE-ALD cycles at room temperature. Maximum growth rates of ∼3.2 A/cycle were measured at electron energies of 80–160 eV. BN film growth was self-limiting versus borazine and electron exposures, as expected for an ALD process. The calculated average hydrogen ESD cross section was σ = 4.2 × 10–17 cm2. Ex situ spectroscopic ellipsometry measurements across the ∼1 cm2 area of the BN film defined by the electron beam displayed good uniformity in thickness. Ex situ X-ray photoelectron spe...

Freestanding LiCoO2/multiwall carbon nanotube/nanocellulose fibril (LCO-MWCNT-NCF) electrodes are fabricated by a vacuum filtration technique. The electrode has a high LCO loading of 20 mg/cm2 with excellent flexibility, uniform material distribution, and low surface resistivity. When coated with 2 ALD cycles of AlF3, LCO-MWCNT-NCF has a high specific capacity of 216 mAh/g at 4.7 V. The freestanding AlF3-coated electrode preserves 75.7% of its initial capacity after 100 cycles and 70% after 160 cycles of charge discharge. In contrast, electrodes coated with 2 ALD cycles of Al2O3 cannot be cycled above 4.5 V. By elimination of the unnecessary weight of current collector, and increasing in the working voltage simultaneously, this freestanding LCO-MWCNT-NCF electrode can significantly improve the gravimetric and volumetric energy density of lithium ion batteries.

Low energy electrons may provide mechanisms to enhance thin film growth at low temperatures. As a proof of concept, this work demonstrated the deposition of gallium nitride (GaN) films over areas of ∼5 cm(2) at room temperature and 100 °C using electrons with a low energy of 50 eV from an electron flood gun. The GaN films were deposited on Si(111) wafers using a cycle of reactions similar to the sequence employed for GaN atomic layer deposition (ALD). Trimethylgallium (Ga(CH(3))(3), TMG), hydrogen (H) radicals and ammonia (NH(3)) were employed as the reactants with electron exposures included in the reaction cycle after the TMG/H and NH(3) exposures. A number of ex situ techniques were then employed to analyze the GaN films. Spectroscopic ellipsometry measurements revealed that the GaN films grew linearly with the number of reaction cycles. Linear growth rates of up to 1.3 Å/ cycle were obtained from the surface areas receiving the highest electron fluxes. Grazing incidence X-ray diffraction analysis revealed polycrystalline GaN films with the wurtzite crystal structure. Transmission electron microscopy (TEM) images showed crystalline grains with diameters between 2 and 10 nm depending on the growth temperature. X-ray photoelectron spectroscopy depth-profiling displayed no oxygen contamination when the GaN films were capped with Al prior to atmospheric exposure. However, the carbon concentrations in the GaN films were 10−35 at. %. The mechanism for the low temperature GaN growth is believed to result from the electron stimulated desorption (ESD) of hydrogen. Hydrogen ESD yields dangling bonds that facilitate Ga−N bond formation. Mass spectrometry measurements performed concurrently with the reaction cycles revealed increases in the pressure of H(2) and various GaN etch products during the electron beam exposures. The amount of H(2) and GaN etch products increased with electron beam energy from 25 to 200 eV. These results indicate that the GaN growth occurs with competing GaN etching during the reaction cycles.

The atomic layer deposition (ALD) of a variety of metal fluorides including ZrF4, MnF2, HfF4, MgF2, and ZnF2 was demonstrated using HF from a HF–pyridine solution. In situ quartz crystal microbalance (QCM) studies were utilized to examine the growth of these metal fluorides. ZrF4 ALD using tetrakis(ethylmethylamido) zirconium and HF as the reactants was studied as a model system. The QCM measurements determined a mass gain per cycle (MGPC) of 35.5 ng/(cm2 cycle) for ZrF4 ALD at 150 °C. This MGPC was equivalent to a growth rate of 0.9 A/cycle at 150 °C. MnF2, HfF4, MgF2, ZnF2, and additional ZrF4 were also grown using bis(ethylcyclopentadienyl) manganese, tetrakis(dimethylamido) hafnium, bis(ethylcyclopentadienyl) magnesium, diethylzinc, and zirconium tetra-tert-butoxide as the metal precursors, respectively. The growth rates for MnF2, HfF4, MgF2, ZnF2, and ZrF4 ALD were 0.4, 0.8, 0.4, 0.7, and 0.6 A/cycle, respectively, at 150 °C. All of these metal fluoride ALD systems displayed self-limiting reactions. ...

Freestanding LiCoO

The first-ever demonstration of stabilized Si/lithium-manganese-rich full cells, capable of retaining >90% energy over early cycling and >90% capacity over more than 750 cycles at the 1C rate (100% depth-of-discharge), is made through the utilization of a modified ionic-liquid electrolyte capable of forming a favorable cathode-electrolyte interface.

The growth of manganese-based films on silicon oxide substrates via the thermal decomposition of two Mn metalorganic complexes, bis(N,N′-diisopropylpentylamidinato)Mn(II) and methylcyclopentadienylmanganese(I) tricarbonyl, was characterized and contrasted by using an instrument equipped with a reactor coupled to a X-ray photoelectron spectroscopy (XPS) analytical chamber. The acetamidinate precursor proved highly reactive, affording the deposition of Mn at reasonable rates, higher at higher temperatures, but also leading to the incorporation of approximately 15% of nitrogen and additional carbon in the grown Mn(0) films. The methylcyclopentadienyl compound, by contrast, proved quite unreactive, even if an electron-impact gas-phase preactivation step recently developed in our laboratory was used. Slow deposition rates were seen with this precursor, appearing to be slower at higher temperature because of an unfavorable kinetic competition with Mn diffusion into the bulk. In both cases, a nonstoichiometric m...

The incorporation of gas-phase electron-impact ionization and activation of metal-organic compounds into atomic layer deposition (ALD) processes is reported as a way to enhance film growth with stable precursors. Specifically, it is shown here that gas-phase activation of methylcyclopentadienylmanganese tricarbonyl, MeCpMn(CO)3, which was accomplished by using a typical nude ion gauge employed in many ultrahigh-vacuum (UHV) studies, enhances its dissociative adsorption on silicon surfaces, affording the design of ALD cycles with more extensive Mn deposition and at lower temperatures. Significantly higher Mn uptakes were demonstrated by X-ray photoelectron spectroscopy (XPS) on both silicon dioxide films and on Si(100) wafers Ar(+)-sputtered to remove their native oxide layer. The effectiveness of this electron-impact activation approach in ALD is explained in terms of the cracking patterns seen in mass spectrometry for the metal-organic precursor used.

There has been much interest in recent years in the use of manganese for the self-formation of diffusion barriers to prevent the electromigration of copper interconnects into the underlying silicon substrate during microelectronic fabrication. However, the films resulting from the deposition of manganese on silicon wafers, which are covered by a thin native silicon dioxide layer, are complex and have not been fully characterized to date. Here we report on X-ray photoelectron spectroscopy (XPS) studies on the nature of films prepared by chemical means using methylcyclopentadienylmanganese tricarbonyl as the precursor. It was found that at the temperatures typically used for deposition, between approximately 550 and 750 K, a manganese silicate layer grows first upon reaction with the top SiO2 surface, and a thin manganese silicide film develops latter at the SiO2/Si(100) interface. The performance of these structures, of the silicide in particular, in microelectronic applications is still to be determined.

The NaOH additive substantially enhances the catalytic activity of Au/SiO2 catalyst inert in catalyzing CO oxidation at temperatures below 150 °C, and Au/NaOH/SiO2 catalyst with a NaOH:Au atomic ratio of 6 is active at room temperature. Both the particle size distribution and the electronic structure of Au nanoparticles were found to be similar in Au/SiO2 and Au/NaOH/SiO2 catalysts, unambiguously proving that hydroxyls on “inert” Au nanoparticles can induce the activation of O2 for CO oxidation at room temperature. The accompanying density functional theory (DFT) calculation results reveal the determining role of COOH(a) in hydroxyls-induced activation of O2 on the Au(1 1 1) surface. Our results successfully elucidate the influence of hydroxyls on the intrinsic activity of Au nanoparticles in CO oxidation, providing novel insights into the role of hydroxyls in the catalytic activity of Au catalysts and advancing the fundamental understanding of oxidation reactions catalyzed by Au catalysts.

The influences of CeO2 microstructures on the structure and catalytic activity of supported Au nanoparticles in CO oxidation have been investigated in Au/CeO2/SiO2 catalysts. CeO2/SiO2 supports with various CeO2 microstructures were prepared and used to prepare Au/CeO2/SiO2 catalysts by deposition–precipitation using HAuCl4 as the precursor. Au(I) species and Au nanoparticles compete for the surface oxygen vacancies on CeO2 and highly dispersive CeO2 on SiO2 facilitates the formation of Au(I) species. Meanwhile, the presence of Au also facilitates the creation and stabilization of surface oxygen vacancies on CeO2. The Au nanoparticle–CeO2 interface plays an important role in the activity of Au/CeO2/SiO2 catalysts in CO oxidation.

We report an easy method of using SiO 2 as the support and HAuCl 4 as the precursor for synthesizing a Au/CoO x /SiO 2 catalyst that is highly active in low-temperature CO oxidation. The surface of SiO 2 was modified with a small amount of highly dispersed CoO x (6 wt%) before the loading of gold. A 78% conversion of CO was achieved at room temperature and 100% at temperatures above 333 K over the Au/CoO x /SiO 2 catalyst in CO oxidation. Compared with Au/SiO 2 , the existence of CoO x greatly enhances the dispersion of gold nanoparticles in Au/CoO x /SiO 2 , which is responsible for the excellent catalytic performance.

Thermal atomic layer etching (ALE) of crystalline aluminum nitride (AlN) films was demonstrated using sequential, self-limiting reactions with hydrogen fluoride (HF) and tin(II) acetylacetonate [Sn(acac)2] as the reactants. Film thicknesses were monitored versus number of ALE reaction cycles at 275 °C using in situ spectroscopic ellipsometry (SE). A low etch rate of ∼0.07 A/cycle was measured during etching of the first 40 A of the film. This small etch rate corresponded with the AlOxNy layer on the AlN film. The etch rate then increased to ∼0.36 A/cycle for the pure AlN films. In situ SE experiments established the HF and Sn(acac)2 exposures that were necessary for self-limiting surface reactions. In the proposed reaction mechanism for thermal AlN ALE, HF fluorinates the AlN film and produces an AlF3 layer on the surface. The metal precursor, Sn(acac)2, then accepts fluorine from the AlF3 layer and transfers an acac ligand to the AlF3 layer in a ligand-exchange reaction. The possible volatile etch produc...

Large Au nanoparticles with an average size of approximately 10 nm supported on inert SiO(2) become active in low-temperature CO oxidation after the addition of NaNO(3). The catalyst structures have been characterized in detail by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and X-ray absorption spectroscopy. The NaNO(3) additive in Au/SiO(2) catalysts does not lead to the formation of fine Au nanoparticles, which are generally considered to be inevitable in low-temperature CO oxidation catalyzed by gold, nor does it alter the electronic structure of Au. The NaNO(3)-induced restructuring of large Au nanoparticles was proposed to create low-coordinated Au sites on the surface capable of catalyzing low-temperature CO oxidation. These results experimentally prove that the activity of supported Au nanoparticles in low-temperature CO oxidation could solely arise from their geometric structure, which greatly deepens the fundamental understandings of Au nanocatalysis.

The surface chemistry of dimanganese decacarbonyl on the native oxide of Si(100) wafers was characterized with the aid of x-ray photoelectron spectroscopy. Initial experiments in a small stainless-steel reactor identified a narrow range of temperatures, between approximately 445 and 465 K, in which the deposition of manganese could be achieved in a self-limiting fashion, as is desirable for atomic layer deposition. Deposition at higher temperatures leads to multilayer growth, but the extent of this Mn deposition reverses at even higher temperatures (about 625 K), and also ifhydrogen is added to the reaction mixture. Extensive decarbonylation takes place below room temperature, but limited C–O bond dissociation and carbon deposition are still seen after high exposures at 625 K. The films deposited at low (∼450 K) temperatures are mostly in the form of MnO, but at 625 K that converts to a manganese silicate, and upon higher doses a manganese silicide forms at the SiO2/Si(100) interface as well. No metallic ...