Lithiation MXene Derivative Skeletons for Wide-Temperature Lithium Metal Anodes

Lithium (Li) metal, as an appealing candidate for the next-generation of high-energy-density batteries, is plagued by its safety issue mainly caused by uncontrolled dendrite growth and infinite volume expansion. Developing new materials that can improve the performance of Li-metal anode is one of the urgent tasks. Herein, a new MXene derivative containing pure rutile TiO₂ and N-doped carbon prepared by heat-treating MXene under a mixing gas, exhibiting high chemical activity in molten Li, is reported. The lithiation MXene derivative with a hybrid of LiTiO₂-Li₃N-C and Li offers outstanding electrochemical properties. The symmetrical cell assembling lithiation MXene derivative hybrid anode exhibits an ultra-long cycle lifespan of 2000 h with an overpotential of ≈30 mV at 1 mA cm⁻², which overwhelms Li-based anodes reported so far. Additionally, long-term operations of 34, 350, and 500 h at 10 mA cm⁻² can be achieved in symmetrical cells at temperatures of −10, 25, and 50 °C, respectively. Both experimental tests and density functional theory calculations confirm that the LiTiO₂-Li₃N-C skeleton serves as a promising host for Li infusion by alleviating volume variation. Simultaneously, the superlithiophilic interphase of Li₃N guides Li deposition along the LiTiO₂-Li₃N-C skeleton to avoid dendrite growth.     

基于蛋白质组学技术研究秦川牛肉宰后贮藏过程中肌红蛋白含量及其衍生物转化

本实验采用4D-非标记蛋白质组学技术研究秦川牛肉贮藏过程中（0～8 d）肌红蛋白含量及其衍生物的转化情况，阐释冷却秦川牛肉中肌红蛋白含量及其衍生物转化的分子机制。结果表明：贮藏过程中，肌红蛋白表达量在宰后0～4 d上升、4～8 d下降，利用非标记蛋白质组学技术鉴定出与肌红蛋白及其衍生物相关的差异蛋白14 种，具体包括代谢酶、氧化还原酶、过氧化物酶、伴侣蛋白4 类，这4 类蛋白的表达共同调控贮藏过程中肌红蛋白含量的变化及其3 种衍生物之间的转化，具体表现为贮藏过程中肌红蛋白表达量整体呈下降趋势，氧合肌红蛋白相对含量持续下降，脱氧肌红蛋白、高铁肌红蛋白相对含量逐渐增加，导致肉色发生褐变。本研究结果有利于理解秦川牛肉贮藏过程肉类变色的复杂生化变化机制。     

Preparation and polymerization of isopimaric acid derivatives

Isopimaric acid is a typical rosin compound and can account for 30% of the total mass of slash pine rosin. The molecular structure of isopimaric acid derivatives features an unsaturated double bond at the C13 position, opening up the possibility of their industrial polymerization. In this study, isopimaric acid (95.4%), methyl isopimarate (99.5%), and allyl isopimarate (95.1%) were prepared as highly pure monomers. New experimental results are presented and mechanisms based on the investigation of free-radical polymerization under UV irradiation are proposed. New rosin monomers for potential value-added utilization of woody biomass are also identified. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47817.     

A note on the value function for constrained control problems

We consider the Mayer optimal control problem with dynamics given by a nonconvex differential inclusion, whose trajectories are constrained to a given set and we obtain a relation between the costate function that appears in the maximum principle and the value function. This relation extends the known conditions existing in the literature for unconstrained problems to those for problems under state constraints.     

The Influence of Ir and Pt Addition on the Synthesis of Fullerenes at Atmospheric Pressure

The addition of metallic Ir and Pt to a fullerene-forming, atmospheric-pressure plasma reactor was found to influence the generation of carbonaceous products. It was observed that the added metals were efficiently dispersed into the plasma and that their presence increased the yield of fullerenes. The addition of Ir led to a noticeable shift in the fullerene distribution towards C₆₀, whereas the addition of Pt increased the proportion of C₆₀ oxides and decreased the proportion of higher fullerenes. Addition of Ir also caused a reduction of the soot particle size and the formation of a considerable quantity of carbon nanotubes.     

Second-Order optical non-linearities of {4-(dimethylamino) stilben z & e 4'-yl} dimesityl borane

Samples of {4-(dimethylamino) stilben Z & E 4'-yl} dimesityl borane (BNS) were synthesised and investigated for their non-linear optical properties. The results show that the quadratic hyperpolarisability of the Z-isomer is smaller than that of the E-isomer, the beta value found for the latter being as high as 60 × 10^?30 esu.     

Kinetic Studies of the Thermal Decomposition of C60H2 in Solution

Thermal decomposition of C₆₀H₂ in C₆D₄Cl₂ solution at 236°C for 2 hours was shown to produce hydrogen as a product, the hydrogen production was successfully followed by NMR. In order to further explore the rule of thermal decomposition of C₆₀H₂, the dynamics of decomposition reaction was studied and the results showed this decomposition reaction accorded with first order reaction dynamical equation. The experiment temperature was ranged separately in 459K, 455K, 451K, and 446K.     

Adsorption and inhibitive properties of benzimidazole derivatives in acid mild steel corrosion

Eight diazoles were investigated as corrosion inhibitors of mild steel in 1 M hydrochloric acid using gravimetric and polarization techniques. It was found that the inhibition efficiency increased with the increase of organic substrate concentration, while the adsorption followed the Frumkin isotherm. A correlation between the electronic parameters (induction and mesomeric effects of the substituents, ionization potential values) as well as those of the chemical structure (molecular area) of diazoles molecules and their inhibiting properties was looked for. The results obtained show that a definite interdependence exists but it is not as simple and straightforward as might be expected.     

Synthesis of some new 3-(2′-heterocyclicethyl)-2-methyl-3,4-dihydroquinazolin-4-one derivatives as antimicrobial agents

3-(2′-Chloroethyl)-2-methyl-3,4-dihydroquinazolin-4-one was reacted with acetylacetone, ethyl acetoacetate and diethylmalonate in the presence of sodium ethoxide to afford the alkylation products IV, V and VI , Compounds IV, V and VI were reacted with hydrazine hydrate, phenylhydrazine, hydroxylamine hydrochloride, urea and thiourea to yield 3-(2′-heterocyclicethyl)-2-methyl-3,4-dihydroquinazolin-4-one derivatives VII-XV . The structures of the synthesized compounds were elucidated by elemental analyses and spectroscopic (IR and XH-NMR) analyses. The prepared compounds were tested for their antimicrobial activities in comparison with tetracycline as a reference compound.     

Preparation,structural elucidation,molecular weight determination,and molecular recognition of first‐ and second‐tier dendrimer molecules

1,3,5‐Triglyceratetriazine [first tier (G₁)] and tri(1,3,5‐triglycerate) triazine [second tier (G₂)] dendrimers were prepared with 1,3,5‐trichlorotriazine and sodium glycerate in a 1 : 3 mass ratio in an ethanolic medium.G₁ and G₂ were amorphous, white, solid substances. Their structures were elucidated with IR, ¹H‐NMR, and ¹³C‐NMR, and their thermal stability was studied with thermogravimetric analysis. The activation energy was calculated with the Freeman–Carroll model. Densities, viscosities, and surface tensions for 0.01–0.08 mol/kg aqueous solutions increased at 0.01 mol/kg for sodium glycerate, 1,3,5‐trichlorotriazine, 1,3,5‐triazine triglycerate chloride, G₁, and G₂. These values were measured at 298.15 K. The apparent molal volume, reduced viscosity, and inherent viscosity were calculated from the densities and viscosities, respectively. The data were regressed for the limiting densities, limiting apparent molal volumes, intrinsic viscosities, limiting inherent viscosities, and limiting surface tensions for solute–solvent interactions. The positive limiting apparent molal volume values were noted in the order of G₂ > 1,3,5‐triazine triglycerate chloride > G₁ > 1,3,5‐trichlorotriazine > sodium glycerate, with weaker hydrophilic intermolecular interactions of G₂. The higher intrinsic viscosity and limiting inherent viscosity values for G₂ implied stronger G₂–H₂O hydrophilic interactions, and the higher limiting apparent molal volume of G₂ indicated slightly higher dynamic conformational changes in comparison with G₁, with stronger structural activities. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008