Solution-processed laminated ZrO2/Al2O3 dielectric for low-voltage indium zinc oxide thin-film transistors

Journal of Sol-Gel Science and Technology - We fabricated a solution-processed laminated dielectric and investigated its structural, optical, and electrical properties. The laminated ZrO2 (Z) and...     

A strategically designed porous iron-iron oxide matrix on graphene for heavy metal adsorption

The iron oxide nanoparticles were transformed to a matrix of iron-iron oxide on the graphene surface at an elevated temperature in a H(2)/Ar atmosphere. The resultant iron-iron oxide dispersed graphene was highly porous, robust and attractive for a variety of potential applications.     

Evidence for spontaneous resolution of icosahedral proline

Here we show experimental evidence for the spontaneous chiral resolution of icosahedral [12Pro+H]+ cluster ion. Molecular simulations reveal that the icosahedron consists of 12 equally spaced prolines where the rigid pyrrolidine ring of each monomer is sticking out of the closed cage. The tightly packed chiral cage traps a single proton in the center cavity. On the other hand, racemic [12Pro+H]+ cluster size exhibits a prismatic structure that can easily incorporate and lose proline monomeric unit sequentially, thus easily forming other geometries. Mechanisms which account for these observations are discussed.     

Room temperature ring-opening metathesis of pyridines by a transient Ti[triple bond]C linkage

The transient titanium alkylidyne complex (PNP)TiCtBu (PNP = N[2-P(CHMe2)2-4-methylphenyl]2-), prepared from alpha-hydrogen abstraction of the corresponding alkylidene-alkyl species (PNP)Ti=CHtBu(CH2tBu), can readily cleave the C-N bond of N-heterocycles such as pyridine and 4-picoline at room temperature to afford azametallabicyclic systems. Experimental and theoretical studies strongly favor a ring-opening metathesis pathway where [2 + 2] cycloaddition of pyridine across the TiC linkage ultimately leads to C-N bond rupture.     

Nanostructured Ni3Sn2 thin film as anodes for thin film rechargeable lithium batteries

Thin film Ni₃Sn₂ anodes were deposited on a Cu substrate by e-beam evaporator at room temperature. The deposited films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). They were tested as anodes for thin film rechargeable lithium batteries. These film electrodes exhibited an excellent cycle performance over 500 cycles. Ni₃Sn₂ films remained without undergoing any crystallographic phase change during cycling.     

Measurement of Reactive Hydroxyl Radical Species Inside the Biosolutions During Non-thermal Atmospheric Pressure Plasma Jet Bombardment onto the Solution

Non-thermal atmospheric pressure plasma jet could generate various kinds of radicals on biosolution surfaces as well as inside the biosolutions. The electron temperature and ion density for this non-thermal plasma jet have been measured to be about 0.8~1.0 eV and 1 × 10¹³ cm^?3 in this experiment, respectively, by atmospheric pressure collisional radiative model and ion collector current. In this context, the hydroxyl OH radical density inside the biosolutions has been also investigated experimentally by ultraviolet absorption spectroscopy when the Ar non-thermal plasma jet has been bombarded onto them. It is found that the emission and absorption profiles for the other reactive oxygen species such as NO (226 nm) and O₂*^? (245 nm) are shown to be very small inside the biosolution in comparison with those for the OH radical species. It is found that the densities of OH radical species inside the biosolutions are higher than those on the surface in this experiment. The densities of the OH radical species inside the deionized water, Dulbecco’s modified eagle medium, and phosphate buffered saline are measured to be about 2.1 × 10¹⁶, 1.1 × 10¹⁶, and 1.0 × 10¹⁶ cm^?3, respectively, at 2 mm downstream from the surface under optimized Ar gas flow of 200 sccm. It is also found that the critical hydroxyl OH radical density for the lung cancer H460 cells to experience an apoptosis is observed to be around 0.3 × 10¹⁶ cm^?3 under 1 min plasma exposure in this experiment.     

Patternable Large‐Scale Molybdenium Disulfide Atomic Layers Grown by Gold‐Assisted Chemical Vapor Deposition

A novel way to grow MoS₂ on a large scale with uniformity and in desired patterns is developed. We use Au film as a catalyst on which [Mo(CO)₆] vapor decomposes to form a Mo‐Au surface alloy that is an ideal Mo reservoir for the growth of atomic layers of MoS₂. Upon exposure to H₂S, this surface alloy transforms into a few layers of MoS₂, which can be isolated and transferred on an arbitrary substrate. By simply patterning Au catalyst film by conventional lithographic techniques, MoS₂ atomic layers in desired patterns can be fabricated.     

Synergistic Activation of Amides and Hydrocarbons for Direct C(sp3)–H Acylation Enabled by Metallaphotoredox Catalysis

The utilizations of omnipresent, thermodynamically stable amides and aliphatic C(sp³)?H bonds for various functionalizations are ongoing challenges in catalysis. In particular, the direct coupling between the two functional groups has not been realized. Here, we report the synergistic activation of the two challenging bonds, the amide C?N and unactivated aliphatic C(sp³)?H, via metallaphotoredox catalysis to directly acylate aliphatic C?H bonds utilizing amides as stable and readily accessible acyl surrogates. N‐acylsuccinimides served as efficient acyl reagents for the streamlined synthesis of synthetically useful ketones from simple C(sp³)?H substrates. Detailed mechanistic investigations using both computational and experimental mechanistic studies were performed to construct a detailed and complete catalytic cycle. The origin of the superior reactivity of the N‐acylsuccinimides over other more reactive acyl sources such as acyl chlorides was found to be an uncommon reaction pathway which commences with C?H activation prior to oxidative addition of the acyl substrate.     

Development and properties of nanostructured thermal spray coatings

Nanostructured thermal spray coatings have been intensively studied because of their potential in a wide variety of industrial applications. In the present paper, current development status of nanostructured thermal spray coatings is presented, mainly based on the results of the authors. In the nanostructured WC–Co wear-resistant coatings, the influence of feedstock characteristics on the coating properties was discussed to suggest the desirable morphology of feedstock for thermal spraying. For the nanostructured Cr₂O₃ based solid-lubricant coatings, the advanced feedstock has been developed in order to solve the inhomogeneity problem of the conventional coatings. Various properties of the nanostructured coatings were evaluated and compared with those of the conventional counterparts. These results clearly demonstrate that the significant improvement in coating performance can be achieved by utilizing proper nanostructured coatings.