Kinetics and Mechanism of the Reduction of Dihydroxydiperiodatoargentate(III) by 1,2-butylene Glycol in Alkaline Medium

Kinetics and mechanism of the reduction of dihydroxydiperiodatoargentate(III) by 1,2-butanediol in alkaline medium were studied by spectrophotometry in the 298.2–318.2 K range. The reaction rate showed pseudo-first order dependence in oxidant and 1 < n_ap< 2 in reductant. The associated rate law is: -d[Ag(III)]_t/dt = { kK₁K₂K₃[CH₃CH₂CHOHCH₂OH]² [Ag(III)]_t/[H₂IO^3-₄][OH^-]+K₁K₂+K₁K₂K₃[CH₃CH₂CHOHCH₂OH] = k.[Ag(III)]_t. A plausible mechanism involving a pre-equilibrium of adduct formation between the complex and reductant was proposed. The activation parameters along with rate constants of the rate-determining step were calculated.     

Transition metal complexes on mesoporous silica nanoparticles as highly efficient catalysts for epoxidation of styrene

We have synthesized a series of catalysts for epoxidation of styrene by immobilizing salicylaldimine transition metal (copper, manganese, and cobalt) complexes on mesoporous silica nanoparticles (MSNs) with diameters of 120-150 nm. The prepared catalysts are characterized by infrared (IR) spectra, thermal gravimetric analyses (TGA), inductively coupled plasma (ICP), CHN elemental analysis, nitrogen adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These catalysts possess excellent catalytic efficiency in epoxidation of styrene when using tert-BuOOH (TBHP) as oxidant. Styrene shows a high conversion (～99%) as well as epoxide selectivity (～80%) over Cu-MSN catalysts, and high conversion (～99%) and moderate epoxide selectivity (～65%) over Mn-MSN and Co-MSN catalysts. The recycling experiment results indicate that these catalysts maintain catalytic activity even after being used for three cycles. Our results indicate that MSNs can serve as better catalyst supports.     

Synthesis,Crystal Structure,and Properties of a Dinuclear Cu(I) Cluster

Abstract

A new dinuclear copper(I) cluster complex, [(o-Tol)₃PCuI₂CuP(o-Tol)₃(DMF)] (1) ((o-Tol)₃P = tris(2- methylphenyl)phosphine, DMF = N, N′-dimethylformamide), has been synthesized and the crystal structure was determined by a single-crystal X-ray diffraction study. The dinuclear copper(I) cluster molecule containing an asymmetric Cu₂I₂P₂O core and the dinuclear clusters are fused together by a strong π–π stacking interaction to form asupramolecular one-dimensional (1D) chain. After having compared the relevant complexes composed of CuI and monodentate triarylphosphine ligands, the impact of the substituent of the triarylphosphine ligand to the subsequent complex structure has also been discussed.Except for a strong π–π* bond, the complex 1 also exhibits a weak metal-to-ligand charge transfer (MLCT) absorption bond in the 430–530-nm region and displays a weak green-yellow emission when irradiated by ultraviolet (UV) light. The thermogravimetric analysis demonstrates that its thermal stability is good, and the corresponding PXRD analysis has revealed that the final, organic-free decomposed product is CuI.     

Synthesis and characterization of MxNb4P2O17

A new series of niobium phosphates with the composition of M_xNb₄P₂₁₇17 (M=Li and Na, X=4; M=Zn, Ca, Mg, Sr and Ba, X=2) have been successfully synthesized. The powder X-ray diffraction (XRD) data of these isostructural compounds, was studied The powder Second Harmonic Generation (SHG) effects of these compounds were about twice of that of KH₂PO₄ (KDP).     

激光多普勒自主测速仪天线安装误差对测速精度的影响

为了减小激光多普勒自主测速仪天线安装误差引起的测速误差,以多普勒频移原理为基础,通过旋转矩阵的复合变换推导出测速误差与安装误差间的函数关系,分析了三个安装误差角对三维测速精度的影响,并对旋转矩阵采用Bursa模型线性化后在整体最小二乘准则下给出安装误差角的最优估计,从而实现测速误差的补偿。仿真结果表明：测速误差随速度的增大而增大,影响纵向、横向测速精度的主要因素是偏航角,影响垂向测速精度的主要因素是纵倾角,补偿后三维测速误差显著减小。     

Amorphous Co-Mo-B Film: A High-Active Electrocatalyst for Hydrogen Generation in Alkaline Seawater

The development of efficient electrochemical seawater splitting catalysts for large-scale hydrogen production is of great importance. In this work, we report an amorphous Co-Mo-B film on Ni foam (Co-Mo-B/NF) via a facile one-step electrodeposition process. Such amorphous Co-Mo-B/NF possesses superior activity with a small overpotential of 199 mV at 100 mA cm⁻² for a hydrogen evolution reaction in alkaline seawater. Notably, Co-Mo-B/NF also maintains excellent stability for at least 24 h under alkaline seawater electrolysis.     

神光Ⅲ原型黑腔物理实验研究

总结了在神光Ⅲ原型激光装置上开展的一系列黑腔物理实验研究,从多个方面研究了黑腔内部等离子体状态和辐射场特性。用真空黑腔能量学研究获得了散射光、辐射温度和不同能段辐射流份额的定标规律,从能量学角度梳理和分析了整个激光黑腔相互作用过程。通过对黑腔中充入低密度低Z气体抑制了腔壁等离子体运动,明显减少了可能造成靶丸预热的金M带辐射流(1.6~4.4 keV)份额。针对黑腔内部不同区域等离子体,研究了光斑区等离子体的运动,分析了其与电子热传导限流因子的关系;研究了冕区等离子体的运动,分析了不同充气等离子体条件对其的影响;在同一发次实验中同时测量了光斑区与再发射区的辐射流比值。     

Synergetic Modulation of Steric Hindrance and Excited State for Anti-Quenching and Fast Spin-Flip Multi-Resonance Thermally Activated Delayed Fluorophore

Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials hold great promise for advanced high-resolution organic light-emitting diode (OLED) displays. However, persistent challenges, such as severe aggregation-caused quenching (ACQ) and slow spin-flip, hinder their optimal performance. We propose a synergetic steric-hindrance and excited-state modulation strategy for MR-TADF emitters, which is demonstrated by two blue MR-TADF emitters, IDAD-BNCz and TIDAD-BNCz , bearing sterically demanding 8,8-diphenyl-8H-indolo[3,2,1-de]acridine (IDAD) and 3,6-di-tert-butyl-8,8-diphenyl-8H-indolo[3,2,1-de]acridine (TIDAD), respectively. These rigid and bulky IDAD/TIDAD moieties, with appropriate electron-donating capabilities, not only effectively mitigate ACQ, ensuring efficient luminescence across a broad range of dopant concentrations, but also induce high-lying charge-transfer excited states that facilitate triplet-to-singlet spin-flip without causing undesired emission redshift or spectral broadening. Consequently, implementation of a high doping level of IDAD-BNCz resulted in highly efficient narrowband electroluminescence, featuring a remarkable full-width at half-maximum of 34 nm and record-setting external quantum efficiencies of 34.3 % and 31.8 % at maximum and 100 cd m⁻², respectively. The combined steric and electronic effects arising from the steric-hindered donor introduction offer a compelling molecular design strategy to overcome critical challenges in MR-TADF emitters.     

关于非均质焊接接头中的J积分断裂判据

采用平面应力弹塑性大变形有限元方法、云纹干涉法以及云纹干涉-有限元混合法,从J积分守恒性与J主导有效性两方面仔细考察了非均质焊接接头中的J积分断裂判据.结果表明,至少对于该文所研究的情形而言,J积分守恒性及J主导有效性均是有条件存在的.因此,在非均质焊接接头中直接应用J积分作为断裂判据是不合适的.     

A novel method of protein extraction from perennial Bupleurum root for 2-DE

The perennial Bupleurum root is thick and woody and contains high levels of interfering compounds. Common protein extraction methods have proved refractory towards the isolation of proteins suitable for 2-DE, due to the presence of interfering compounds. A novel method for extracting proteins suitable for 2-DE was established to overcome these problems. The main characteristic of this protocol is the partitioning of the proteins into the aqueous (fraction A-2), chloroform and isoamyl alcohol phases (A-3), and the interphase (A-1). The proteins are then extracted from each of these phases. From A-1, 85% (extracted protein against total proteins) proteins could be extracted and purified. For fraction A-2, a novel phenol extraction step is employed for the extraction of proteins. Based on the well-resolved 2-DE patterns, our protein preparation is free of interfering compounds. Using these methods (A-1, A-2, and A-3-3), a total of 3662 (1526 + 1128 + 1008) spots could be separated, and a protein yield of about 1.41 mg per 1.0 g fresh root material was obtained. To our knowledge, this is the first time that a protocol for protein extraction from perennial Bupleurum root has been reported that gives reproducible results. The protocol is expected to be applicable to other recalcitrant plant tissues as well.