Crystal structure of the tetranickel complex with Ipropanethiolate

The title complex [Ni₄(SPrⁱ)₈] was confirmed by single crystal X-ray crystal diffraction analysis. The crystals are monoclinic, space group P2/n with a = 12.760(3), b = 10.059(2), c = 14.484(3) Å, α = 90, β = 93.70(3), γ = 90°, V = 1855.3(6) ų, Z = 4, F(000) = 880, D_c = 1.496 g/cm³, μ = 2.463 mm^?1, the final R = 0.0352 and wR = 0.0580. A total of 18,588 reflections were collected, of which 4404 were independent (R_int = 0.0631). In the crystal packing diagram, intermolecular C—H···Ni hydrogen bonds stabilize the solid state of the title complex.     

Tuner design and RF test of a four-rod RFQ

A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the electrodes is not flat. The resonant frequency needs to be tuned to the operating value. And the frequency needs to be compensated for temperature change during high power RF test and beam test. As tuning such a RFQ is difficult, plate tuners and stick tuners are designed. This paper will present the tuners design, the tuning procedure, and the RF properties of the RFQ.

     

4,5-二苯基-2-(9-苯基-9H-3-咔唑基)-1H-咪唑的合成及其性能

以联苯甲酰、对溴苯甲醛和乙酸铵为原料，经缩合反应制得2-(4-溴苯基)-4,5-二苯基咪唑(1); 1与N-苯基-3-咔唑硼酸经Suzuki偶联反应合成了一种具有D-π-A结构的新型咪唑衍生物4,5-苯基-2-(9-苯基-9H-3-咔唑基)-1H-咪唑(2），其结构经¹H NMR, ¹³C NMR, IR和MS(EI)表征。采用FL, UV-Vis，循环伏安法（CV）和理论计算对2的光电性能进行了研究。结果表明：2的最大吸收波长为302 nm和326 nm，荧光发射波长为395 nm和412 nm, HOMO和LUMO轨道能级分别为5.35 eV和2.14 eV。     

Ion Product of Pure Water Characterized by Physics-Based Water Model

Pure water has been characterized for nearly a century, by its dissociation into hydronium (H₃O)¹⁺ and hydroxide (HO)^1- ions. As a chemical equilibrium reaction, the equilibrium constant, known as the ion product or the product of the equilibrium concentration of the two ion species, has been extensively measured by chemists over the liquid water temper-ature and pressure range. The experimental data have been nonlinear least-squares fitted to chemical thermodynamic-based equilibrium equations, which have been accepted as the industrial standard for 35 years. In this study, a new and statistical-physics-based water ion product equation is presented, in which, the ions are the positively charged protons and the negatively charged proton-holes or prohols. Nonlinear least squares fits of our equation to the experimental data in the 0-100 ℃ pure liquid water range, give a factor of two better precision than the 35-year industrial standard.     

Zero-valent iron particles embedded on the mesoporous silica–carbon for chromium (VI) removal from aqueous solution

Journal of Nanoparticle Research - The demand for metal nanoparticles is increasing strongly. Transferred arc synthesis is a promising process in this respect, as it shows high production rates,...