NASICON-based H2 Sensor Using CoCrMnO4 Insensitive Reference Electrode and Buried Au Sensing Electrode

This work focuses on the H2 sensing performance of the sensor with buried Au sensing electrode and spi- nel-type oxide CoCrMnO4 insensitive reference electrode within sodium super ionic conductor（NASICON） film. The sensor showed the highest response to H2 gas on the insensitive material sintering at 800 ~C. Compared with those of the traditional structure device, the sensitivity and selectivity of the sensor using buried sensing electrode were greatly improved, giving a response of-177 mV in 9x10 5 g/L H2, which was about 3.5 times higher than that of sensors with traditional structure. Moreover, the AV value of the sensing device exhibited linear relationship to the logarithm of H2 concentration and the sensitivity（slope） was -135 mV/decade. A sensing mechanism related to the mixed potential was proposed for the present sensor.     

Adsorption of uranium ions from aqueous solution by amine-group functionalized magnetic Fe3O4 nanoparticle

The magnetic Fe₃O₄ nanoparticle was functionalized by covalently grafting amine group with (3-aminopropyl) trimethoxy silane, and the Fe₃O₄–NH₂ nanoparticle and the Fe₃O₄ nanoparticle were characterized by Fourier transform infrared, and X-ray diffraction. And the results indicated the amine-group was immobilized successfully on the surface of Fe₃O₄. The adsorption behavior of uranium from aqueous solution by the Fe₃O₄ nanoparticle and the Fe₃O₄–NH₂ nanoparticle was investigated using batch experiments. The pH of initial aqueous solution at 5.0 and 6.0 were in favour of adsorption of uranium, and the adsorption percentage of uranium by the Fe₃O₄ nanoparticle and the Fe₃O₄–NH₂ nanoparticle were 81.2 and 95.6 %, respectively. In addition, the adsorption of uranium ions could be well-described by the Langmuir, Freundlich isotherms and pseudo-second kinetic models. The monolayer adsorption maximum capacity of the Fe₃O₄ nanoparticle and the Fe₃O₄–NH₂ nanoparticle were 85.35 and 268.49 mg/g at 298.15 K, respectively, which indicate the adsorption capacity the Fe₃O₄ nanoparticle was improved by amine functionalization.     

Hydrothermal synthesis of peony-like CuO micro/nanostructures for high-performance lithium-ion battery anodes

The peony-like CuO micro/nanostructures were fabricated by a facile hydrothermal approach. The peonylike CuO micro/nanostructures about 3-5 μm in diameter were assembled by CuO nanoplates. These CuO nanoplates, as the building block, were self-assembled into multilayer structures under the action of ethidene diamine, and then grew into uniform peony-like CuO architecture. The novel peony-like CuO micro/nanostructures exhibit a high cycling stability and improved rate capability. The peony-like CuO micro/nanostructures electrodes show a high reversible capacity of 456 mAh/g after 200 cycles, much higher than that of the commercial CuO nanocrystals at a current 0.1 C. The excellent electrochemical performance of peony-like CuO micro/nanostructures might be ascribed to the unique assembly structure, which not only provide large electrode/electrolyte contact area to accelerate the lithiation reaction, but also the interval between the multilayer structures of CuO nanoplates electrode could provide enough interior space to accommodate the volume change during Li~+ insertion and de-insertion process.     

Study on the synthesis of novel fluorescent macrocyclic sensors and their sensitive properties for Cu2+ and Fe3+ in aqueous solution

In this work, we synthesised and characterised three novel fluorescence macrocyclic sensors containing optically active dansyl groups. The studies for the interaction of the synthesised compounds with various mental ions (Li⁺, Na⁺, K⁺, Ag⁺, Mg²⁺, Ca²⁺, Ba²⁺, Pb²⁺, Zn²⁺, Co²⁺, Cd²⁺, Hg²⁺, Ni²⁺, Cu²⁺, Mn²⁺, Cr³⁺, Al³⁺, Fe³⁺) were performed by fluorescence titration, Job’s plot, ESI-MS and DFT calculations. The results showed that the sensors 1a–1c displayed selective recognition for Cu²⁺ and Fe³⁺ ions and formed stoichiometry 1:1 complex through PET mechanism in DMSO/H₂O solution (1:1, v/v, pH 7.4 of HEPES). The binding constant (K) and detection limit were calculated.     

贵金属负载的棒状ZnO复合光催化剂的制备及其提升的光催化性能

以水热制备的ZnO纳米棒为基底,通过乙二醇液相还原法负载不同贵金属颗粒(Pt、Pd、Ru)构筑贵金属负载的ZnO纳米棒复合光催化剂。实验结果表明在制备条件相同时,Pt/ZnO样品中Pt颗粒尺寸较小,分布均匀;Pd/ZnO样品中Pd颗粒尺寸较大且团聚严重;Ru/ZnO样品则几乎没有Ru颗粒负载。在紫外光照射下降解亚甲基蓝的反应中,Pt/ZnO表现出最高的光催化性能,Pd/ZnO样品次之,而Ru/ZnO则表现出与ZnO纳米棒相似的光催化活性;表明小尺寸和大小均匀的贵金属颗粒对ZnO纳米棒的催化性能有着显著的提升作用。对Pt/ZnO来说,当Pt载量为3.2%时Pt/ZnO催化剂的光催化活性最高。     

Ag Nanoparticle/Nanofibrillated Cellulose Composite as an Effective and Green Catalyst for Reduction of 4-Nitrophenol

In this work, silver nanoparticles (Ag NPs) prepared through in situ green and facile synthesis by using nanofibrillated cellulose (NFC) hydrogel as support, stabilizer and reducing agent by two different methods. Their catalytic abilities were examined for conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The structure of as-synthesized composites with different AgNO₃ concentrations were characterized by ultraviolet–visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy; energy dispersive spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Results show that all nanocomposites demonstrated excellent catalytic activity. Among them, Ag@NFC-2 sample, with spherical and well-dispersed Ag NPs along the nanofiber, produced by the second method having 0.25 M AgNO₃ concentration presented outstanding catalytic efficiency.     

Partition distance in graphs

If G is a graph and \(\mathcal{P}\) is a partition of V(G), then the partition distance of G is the sum of the distance between all pairs of vertices that lie in the same part of \(\mathcal{P}\). This concept generalizes several metric concepts and is dual to the concept of the colored distance due to Dankelmann, Goddard, and Slater. It is proved that the partition distance of a graph can be obtained from the Wiener index of weighted quotient graphs induced by the transitive closure of the Djokovi?–Winkler relation as well as by any partition coarser than it. It is demonstrated that earlier results follow from the obtained theorems. Applying the main results, upper bounds on the partition distance of trees with prescribed order and radius are proved and corresponding extremal trees characterized.     

A new multistep finite difference pair for the Schrödinger equation and related problems

In this paper and for the first time in the literature, we introduce a new three-stages symmetric six-step finite difference pair with optimal phase and stability properties. The basic characteristics of the new finite difference pair are:

1. 1.
   Is a symmetric hybrid six-step method,
    
2. 2.
   Is of three stages
    
3. 3.
   Is of twelfth algebraic order,
    
4. 4.
   Has vanished the phase-lag,
    
5. 5.
   Has vanished the derivatives of the phase-lag up to order four.
    

For this new finite difference pair we present a detailed analysis which consists of the following:

1. 1.
   The development of the new three-stages symmetric six-step finite difference pair
    
2. 2.
   The presentation of the local truncation error of the new finite difference pair
    
3. 3.
   A comparative error analysis of the new finite difference pair with other finite difference pairs of the same family: the the classical finite difference pair of the family (i.e. the finite difference pair with constant coefficients), the recently developed finite difference pairs of the same family with vanished phase-lag and its first derivative, the recently developed scheme of the same family with vanished phase-lag and its first and second derivatives and finally with the recently developed finite difference algorithm of the same family with vanished phase-lag and its first, second and third derivatives .
    
4. 4.
   A stability and an interval of periodicity analysis and
    
5. 5.
   Finally, the evaluation of the accuracy and computational efficiency of the new three-stages symmetric six-step finite difference pair for the solution of the Schrödinger equation.
    

The theoretical and numerical analysis of the produced new three-stages symmetric six-step finite difference pair, which are presented in this paper, show the effectiveness of the new scheme compared with other known or recently developed algorithms of the literature.

     

Modified two-derivative Runge–Kutta methods for the Schrödinger equation

A family of modified two-derivative Runge–Kutta (MTDRK) methods for the integration of the Schrödinger equation are obtained. Two new three-stage and fifth order TDRK methods are derived. The numerical results in the integration of the radial Schrödinger equation with the Woods–Saxon potential are reported to show the high efficiency of our new methods. The results of the error analysis are illustrated by the resonance problem.     

The structural modeling of EF-hand motifs in parvalbumin

Parvalbumin (Parv) is a typical protein with EF-hand motifs that play an important role in many physiological processes. We present a novel free energy to model the skeletal C\(_\alpha \) chain of the protein from the basic principle of mathematics and physics. Starting from the crystal structure of Parv (PDB code 2PVB), we first analyze the profile of the C\(_\alpha \) bond and torsion angles over the segment that contains the secondary structures. Then the parameters in the energy function are evaluated for the helix ABCD fragment that contains two EF-hand domains in Parv. Meanwhile an eight-soliton configuration at the energy minimum is constructed to model the conformation of ABCD fragment. The deviation of the conformation constructed from the model away from the crystal structure is as small as 1.28 Å. The structural modeling stems from the physical energy, which is a benefit relative to the statistics-based or knowledge-based technologies.