高温超导无绝缘线圈励磁电压特性研究

本文通过实验研究了焊锡浸渍、励磁电流PI控制、励磁速率以及励磁幅值对高温超导无绝缘线圈励磁电压特性的影响。实验结果表明:高温超导无绝缘线圈励磁电压具有时延特性,焊锡浸渍、励磁电流PI控制分别会增大和减小时延特性,而励磁速率和励磁幅值不会影响时延特性;励磁电压幅值随励磁速率增大而增大;焊锡浸渍可降低励磁电压幅值,而励磁电流控制对励磁电压幅值影响不明显。     

Demonstrating nonlocality-induced teleportation through Majorana bound states in a semiconductor nanowire

It was predicted by Tewari et al. (2008) [15] that a teleportation-like electron transfer phenomenon is one of the novel consequences of the existence of Majorana fermion, because of the inherently nonlocal nature. In this work we consider a concrete realization and measurement scheme for this interesting behavior, based on a setup consisting of a pair of quantum dots which are tunnel-coupled to a semiconductor nanowire and are jointly measured by two point-contact detectors. We analyze the teleportation dynamics in the presence of measurement back-action and discuss how the teleportation events can be identified from the current trajectories of strong response detectors.     

Synthesis of a Novel Phosphorus-Containing Curing Agent and Its Effects on the Flame Retardancy,and Thermal Stability of Epoxy Resins

Russian Journal of Applied Chemistry - A novel curing agent containing phosphorus and carboxyl group compound diphenyl(2,3-dicarboxylpropyl)phosphine oxide (DPDCPPO) was synthesized and used as a...     

Gold‐Catalyzed Multiple Cascade Reaction of 2‐Alkynylphenylazides with Propargyl Alcohols

An unprecedented gold‐catalyzed multiple cascade reaction between 2‐alkynyl arylazides and alkynols has been developed, allowing for the step‐economical synthesis of pyrroloindolone derivatives with a wide range of structural diversity. In this reaction, the gold complex participates in triple catalysis in tandem fashion. Moreover, the efficient chirality transfer from optically pure alkynol substrates enables facile access to chiral pyrroloindolone derivatives with two stereogenic centers, including a quaternary one, with excellent levels of optical purity.     

Synthesis of Honeycomb-Structured Beryllium Oxide via Graphene Liquid Cells

Using high-resolution transmission electron microscopy and electron energy-loss spectroscopy, we show that beryllium oxide crystallizes in the planar hexagonal structure in a graphene liquid cell by a wet-chemistry approach. These liquid cells can feature van-der-Waals pressures up to 1 GPa, producing a miniaturized high-pressure container for the crystallization in solution. The thickness of as-received crystals is beyond the thermodynamic ultra-thin limit above which the wurtzite phase is energetically more favorable according to the theoretical prediction. The crystallization of the planar phase is ascribed to the near-free-standing condition afforded by the graphene surface. Our calculations show that the energy barrier of the phase transition is responsible for the observed thickness beyond the previously predicted limit. These findings open a new door for exploring aqueous-solution approaches of more metal-oxide semiconductors with exotic phase structures and properties in graphene-encapsulated confined cells.     

Iron carbonyl thioboronyls: effect of substitution of sulfur for oxygen in the viability of binuclear complexes toward dissociation reactions

The recent discovery of boronyl complexes of the type (R₃P)₂Pt(BO)X (R = cyclohexyl; X = halogen) makes of interest the chemistry of complexes of the related thioboronyl (BS) ligand. In this connection, the binuclear iron carbonyl complex Fe₂(BS)₂(CO)₈ is predicted by density functional theory to have a symmetrical unbridged structure similar to the valence isoelectronic Mn₂(CO)₁₀. Higher-energy unsymmetrical (OC)₅Fe → Fe(BS)₂(CO)₃ structures are also found as well as a doubly bridged Fe₂(BS)₂(CO)₆(µ-CO)₂ structure. The complex Fe₂(BS)₂(CO)₈ is predicted to be viable toward symmetrical dissociation into Fe(BS)(CO)₄ fragments. However, the unsymmetrical dissociation of Fe₂(BS)₂(CO)₈ into Fe(CO)₅ + Fe(BS)₂(CO)₃ is predicted to be exothermic by ~9 kcal mol^?1. The low-energy structures of the mononuclear Fe(BS)₂(CO)₃ include structures in which the two BS ligands have coupled to form a B₂S₂ ligand through B–B bond formation.     

Facile synthesis of Pd-decorated ZnO nanoparticles for acetone sensors with enhanced performance

ZnO and Pd nanoparticles (NPs) with average diameter of 38 and 10 nm were prepared in advance through a chemical solution method. Pd-functionalized ZnO nanoparticles (Pd@ZnO) were simply synthesized by adding ethanol solution of Pd NPs into ZnO powder, and annealing in argon atmosphere at 500 °C for 1 h after grinding for 30 min. The morphology and structure of the materials were systemically analyzed using Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) techniques. A weak peak in the XRD pattern of Pd@ZnO belonging to the (111) plane of elemental Pd indicated successfully loading of Pd. EDS and TEM results further confirmed successfully coating of Pd NPs onto the surface of ZnO. Sensors using ZnO NPs decorated with Pd (1 wt%) on the surface of exhibited highly elevated sensitivity of 76 in comparing with the response of 36 when based on pure ZnO NPs. In addition, such modification also resulted in a decrease in the operating temperature from 370 to 340 °C for 100 ppm acetone vapor. The sensing mechanism of the sensor based on Pd@ZnO NPs is discussed. Addition of Pd NPs can play an important role in improving the performance of gas sensors, including high sensitivity, good selectivity, and short response/recovery times.     

Lone-Pair Enhanced Birefringence in an Alkaline-Earth Metal Tin(II) Phosphate BaSn2(PO4)2

The first alkaline-earth metal tin(II) phosphate, BaSn₂(PO₄)₂, has been discovered, which consists of layered structures constructed from strictly alternating [SnO₃]⁴⁻ and [PO₄]³⁻ moieties. This compound is expected to have a large birefringence with Δn≈0.071 at 1064 nm, owing to the presence of stereochemically active lone pair metal cations.