Optimal design of gears contact interface modification for an objective as minimum impact resistance of initial meshing-in time domain

Meccanica - In gear pair actual alternating meshing process, the comprehensive errors of the transmission system and the thermal elastic deformation of the teeth body cause the gears in the meshing...     

高居里温度铁电单晶PIN-PT的机电性能

弛豫铁电单晶Pb(In_1/2Nb_1/2)O₃-PbTiO₃(PIN-PT)相较于常用的Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃(PMN-PT)具有更高的居里温度,在高稳定性、高性能的传感器、换能器方面具有应用前景。本工作采用谐振法研究了[001]方向极化的0.66PIN-0.34PT铁电单晶的全矩阵机电性能参数。0.66PIN-0.34PT 单晶的三方-四方相变温度(T_RT)约为160 ℃,居里温度(T_C)约为260 ℃,室温压电系数d₃₃、d₃₁、d₁₅分别为1 340 pC/N、-780 pC/N、321 pC/N,介电常数ε^T₃₃、ε^S₃₃、ε^T₁₁、ε^S₁₁分别为2 700、905、2 210、1 927,机电耦合系数 k₃₃、k₃₁、k₁₅、k_t分别为 87%、58%、38%、61%。其纵向压电常数(d₃₃)和纵向机电耦合系数(k₃₃)小于 PMN-PT 单晶,但是横向压电性能(d₃₁)和剪切压电性能(d₁₅)都略高于PMN-PT单晶。另外,研究了机电耦合性能随温度的变化趋势,发现0.66PIN-0.34PT单晶在150 ℃以下有较好的温度稳定性。     

Syntheses,Crystal Structures and Fluorescence Properties of Three Complexes Based on 2,2'-Quinoline-4,4'-dicarboxylic Ligands

Crystallography Reports - Three new coordination complexes, [Mn(L)(H2O)4⋅(H2O)3]2 (1), [Mg(L)(H2O)4⋅(H2O)3]2 (2), and [Cu(L)(phen)⋅(H2O)4]2 (3) (H2L =...     

Alkaline oxygen evolution: exploring synergy between fcc and hcp cobalt nanoparticles entrapped in N-doped graphene

Herein, we report a Mott-Schottky catalyst by entrapping cobalt nanoparticles inside the N-doped graphene shell (Co@NC). The Co@NC delivered excellent oxygen evolution activity with an overpotential of merely 248 mV at a current density of 10 mA cm^–2 with promising long-term stability. The importance of Co encapsulated in NC has further been demonstrated by synthesizing Co nanoparticles without NC shell. The synergy between the hexagonal close-packed (hcp) and face-centered cubic (fcc) Co plays a major role to improve the OER activity, whereas the NC shell optimizes the electronic structure, improves the electron conductivity, and offers a large number of active sites in Co@NC. The density functional theory calculations have revealed that the hcp Co has a dominant role in the surface reaction of electrocatalytic oxygen evolution, whereas the fcc phase induces the built-in electric field at the interfaces with N-doped graphene to accelerate the H⁺ ion transport.     

Direct Synthesis of Adipic Esters and Adiponitrile via Photoassisted Cobalt-Catalyzed Alkene Hydrodimerization

The direct hydrodimerization of acrylates and acrylonitrile offers a general streamlined access to industrially important intermediates to nylon 6,6. However, a practical catalytic method for this process has thus far underdeveloped owing to the challenges in regioselectivity and environmental compatibility of applied reagents. Here, we report a cobalt-catalyzed tail-to-tail hydrodimerization of activated alkenes driven by a visible-light photoredox catalysis at ambient temperature, which is applicable to both adipates and adiponitrile synthesis from potentially renewable feedstocks. This protocol utilizes half equivalent of hantzsch ester as a recyclable two-electron and two-proton donor with the assistance of catalytic amount of base as a proton shuttle, and has been shown to be highly regioselective and efficient for hydrodimerizing various activated alkenes to 1,4-difunctionalized butane derivatives.     

Influence of inherent alkali metal chlorides on pyrolysis mechanism of a lignin model dimer based on DFT study

Journal of Thermal Analysis and Calorimetry - In order to understand the catalytic effects of inherent inorganic elements in biomass on the pyrolysis mechanism of lignin, density functional theory...     

Thermal behaviour of glazed ceramic bodies

Journal of Thermal Analysis and Calorimetry - Flower-shaped Ni-doped Fe3O4/SnS2 composite was synthesized by a one-pot solvothermal method, where nanosized Ni-doped Fe3O4 particles were dispersed...     

An improved evaluation of the neutron background in the PandaX-Ⅱ experiment

In dark matter direct detection experiments,neutron is a serious source of background,which can mimic the dark matter-nucleus scattering signals.In this paper,we present an improved evaluation of the neutron background in the PandaX-II dark matter experiment by a novel approach.Instead of fully relying on the Monte Carlo simulation,the overall neutron background is determined from the neutron-induced high energy signals in the data.In addition,the probability of producing a dark-matter-like background per neutron is evaluated with a complete Monte Carlo generator,where the correlated emission of neutron(s)andγ(s)in the(α,n)reactions and spontaneous fissions is taken into consideration.With this method,the neutron backgrounds in the Run 9(26-ton-day)and Run 10(28-ton-day)data sets of PandaX-II are estimated to be(0.66±0.24)and(0.47±0.25)events,respectively.