Solubility and dissolution thermodynamics of tetranitroglycoluril in organic solvents at 295–318 K

The solubility data of tetranitroglycoluril in acetone, methanol, ethanol, ethyl acetate, nitromethane and chloroform at temperatures ranging from 295–318 K were measured by gravimetric method. The solubility data of tetranitroglycoluril were fitted with Apelblat semiempirical equation. The dissolution enthalpy, entropy and Gibbs energy of tetranitroglycoluril were calculated using the Van’t Hoff and Gibbs equations. The results showed that the Apelblat semiempirical equation was significantly correlated with solubility data. The dissolving process was endothermic, entropy-driven, and nonspontaneous.     

Analysis of Vinyl Chloride in Vapor Phase of Mainstream Cigarette Smoke by GC–MS Under ISO and Health Canada Intensive Machine Smoking Regimens

Vinyl chloride (VC) in the vapor phase of mainstream cigarette smoke was determined under both International Organization for Standardization (ISO) and Health Canada intensive (HCI) machine smoking regimens, which was suspected to be carcinogenic compound. VC was collected by passing the mainstream cigarette smoke through a Cambridge Filter Pad (CFP) into cryogenic traps containing methanol. The impinger solutions were fortified with VC-d ₃ and analyzed by GC–MS. Limits of detection for vinyl chloride was 0.9 ng mL^?1 with the recovery in the range of 93.2–98.4 %. Moreover, the intra-day and inter-day precision was 7.39 and 9.77 %, respectively. Under HCI machine smoking regimen, the vinyl chloride yields in vapor phase of mainstream cigarette smoke were much higher and the average increase was greater than 100 % compared with those under ISO smoking condition.     

Synthesis of Phenols: Organophotoredox/Nickel Dual Catalytic Hydroxylation of Aryl Halides with Water

A highly effective hydroxylation reaction of aryl halides with water under synergistic organophotoredox and nickel catalysis is reported. The OH group of the resulting phenols originates from water, following deprotonation facilitated by an intramolecular base group on the ligand. Significantly, aryl bromides as well as less reactive aryl chlorides served as effective substrates to afford phenols with a wide range of functional groups. Without the need for a strong inorganic base or an expensive noble‐metal catalyst, this process can be applied to the efficient preparation of diverse phenols and enables the hydroxylation of multifunctional pharmaceutically relevant aryl halides.     

Controlled synthesis of mesoporous SiO2/Ni3Si2O5(OH)4 core-shell microspheres with tunable chamber structures via a self-template method

Mesoporous SiO2/Ni3Si2O5(OH)4 core-shell microspheres with tunable chamber structures have been synthesized by the reaction between Ni(Ac)2.4H2O and SiO2 microspheres via a simple self-template approach.     

非齐次马氏链的中心极限定理

本文将针对非齐次马氏链的转移矩阵列在Ces`aro收敛意义下,利用鞅的中心极限定理证明一个不同于Dobrushin结果的非齐次马氏链的中心极限定理。     

二叉树上分枝马氏链的强大数定理

首先给出了在可列状态空间取值的二叉树上分枝马氏链定义的离散形式,然后建立了二叉树上分枝马氏链的若干强极限定理,最后研究了二叉树上有限状态分枝马氏链的强大数定理．     

Environmentally friendly chemical route to vanadium oxide single-crystalline nanobelts as a cathode material for lithium-ion batteries

Orthorhombic V(2)O(5) single-crystalline nanobelts with widths of 100-300 nm, thicknesses of 30-40 nm, and lengths up to tens of micrometers have been synthesized on a large scale in a hydrogen peroxide aqueous solution by an environmentally friendly chemical route. Such nanobelts grow along the direction of [010]. The influence of the reaction time on the crystal structures and morphologies of the resulting products are investigated. A probable dehydration-recrystallization-cleavage mechanism for the formation of V(2)O(5) nanobelts is proposed. The experiments demonstrate that the use of a nanosized belt-like structure can considerably enhance the specific discharge capacity in lithium-ion batteries.     

Tree-Indexed Markov Chains in Random Environment and Some of Their Strong Limit Properties

In this paper, the authors first introduce the tree-indexed Markov chains in random environment, which takes values on a general state space. Then, they prove the existence of this stochastic process, and develop a class of its equivalent forms. Based on this property, some strong limit theorems including conditional entropy density are studied for the tree-indexed Markov chains in random environment.