Search Results

You are looking at 1 - 10 of 16 items for

  • Author or Editor: L. Yi x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

The biological activity of a kind of hetero-bimetallic Schiff-base complex was studied using Escherichia coli (E. coli) cell as the target. By microcalorimetry, the difference of anti-bacterial activity between the binuclear Schiff-base and the ligand was determined and analyzed. To analyze the inhibition of the bacterial growth internally, the E. coli cells grown in the presence of hetero-bimetallic Schiff-base complex were observed by scanning electron microscopy. The images in high resolution revealed the damage of outer cell membrane caused the inhibitory effect on E. coli. Inductively coupled plasma-mass spectrometry results proved the absorption of the complex by cells, which confirmed the interaction between the Schiff-base and biological macromolecule.

Restricted access

Abstract  

The peak temperature (T p) and different temperature (ΔT) are the basic information in the differential thermal analysis (DTA). Considering the kinetic relation and the heat equilibrium in DTA, a correctional differential kinetic equation (containing T p and ΔT parameter) is proposed. In the dehydration reaction of CaC2O4·H2O, the activation energy calculated from the new equation showed some smaller than that from Kissinger equation, but some bigger than that from Piloyan equation.

Restricted access

Abstract  

The complex from reaction of neodymium chloride six-hydrate with salicylic acid and 8-hydroxyquinoline, Nd(C7H5O3)2·(C9H6NO), was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [NdCl3·6H2O(s)], [2C7H6O3(s)], [C9H7NO(s)] and [Nd(C7H5O3)2·(C9H6NO)(s)] in a mixed solvent of anhydrous ethanol, dimethyl formamide (DMF) and perchloric acid were determined by calorimetry at 298.15 K. Based on Hess’ law, a new chemical cycle was designed, and the enthalpy change of the reaction

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$NdCl_3 \cdot 6H_2 O(s) + 2C_7 H_6 O_3 (s) + C_9 H_7 NO(s) = Nd(C_7 H_5 O_3 )_2 \cdot (C_9 H_6 NO)(s) + 3HCl(g) + 6H_2 O(l)$$ \end{document}
((1)) was determined to be Δr H m Θ=117.89±0.37 kJ mol−1. From data in the literature, through Hess’ law, the standard molar enthalpy of formation of Nd(C7H5O3)2·(C9H7NO)(s) was estimated to be Δf H m Θ[Nd(C7H5O3)2·(C9H6NO)(s), 298.15 K]=−2031.80±8.6 kJ mol−1.

Restricted access

Summary  

Sediment core samples were collected in the largest urban Lake Donghu (Stations I and II) in China, and the activities of 210Pb, 226Ra and 137Cs were measured by gamma-ray spectrometry. The sedimentation rates, calculated by 210Pb constant rate of supply (CRS) model, ranged from 0.11 to 0.65 (average 0.39) cm. y-1at Station I, and from 0.21 to 0.78 (average 0.46) cm. y-1at Station II. Sedimentation rate calculated by 137Cs as a time marker was 0.55 cm. y-1at Station II. Based on the average sedimentation rate, we obtained 769 and 147 t. y-1for nitrogen and phosphorus retentions in Lake Donghu sediments, respectively.

Restricted access

Abstract  

In this study, the thermal stability of sisal in cycle process was investigated between room temperatures and 600°C in various conditions (in air, in composites, in argon) by thermogravimetry and mechanical testing measurement. The results indicated that the thermal stability of sisal was worse in air before five times of thermal cycles, but after the five times thermal stability of sisal in composites was better. In different conditions of same cycles process, the thermal stability of sisal was different. With increasing of thermal cycles times, the max. load (is the maximum strength in stress-strain curve) of sisal fiber showed downtendency in different conditions and decreased most obviously in composites.

Restricted access

Abstract  

The solid-state coordination reaction: Nd(NO3)36H2O(s)+4Ala(s) → Nd(Ala)4(NO3)3H2O(s)+5H2O(l) and Er(NO3)36H2O(s)+4Ala(s) → Er(Ala)4(NO3)3H2O(s)+5H2O(l) have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L–1 HCl solvent of these two solid-solid coordination reactions have been measured using a calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(Ala)4(NO3)3H2O, s, 298.2 K] and[Er(Ala)4(NO3)3H2O, s,298.2 K] at 298.2 K have been determined to be Δf H m 0 [Nd(Ala)4(NO3)3H2O,s, 298.2 K]=–3867.2 kJ mol–1, and Δf H m 0 [Er(Ala)4(NO3)3H2O, s, 298.2 K]=–3821.5 kJ mol–1.

Restricted access

Abstract  

In the present study, the characteric-structure relationship of epoxidized soybean oils (ESO) with various degrees of epoxidation has been investigated. FTIR analysis was used to identify the relative extent of epoxidation of the samples during the epoxidation reaction. The viscosities of ESO were much higher than that of the raw oil, viscosity increased with degree of epoxidation. The viscous-flow activation energy of ESO was determined to be higher than that of the raw oil (20.72 to 77.93% higher). Thermogravimetry analysis (TG) of ESO was used to investigate the thermodynamic behavior of the samples. With increasing degree of epoxidation, the thermal stability of the samples initially decreased, then increased at the final reacting stage. Differential scanning calorimeter (DSC) indicated that the melting point of ESO was higher than that of soybean oil. Gel permeation chromatography (GPC) indicated the molecular mass of the samples increased initially, then decreased, with an increase in the extent of epoxidation.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: L. Xu, Y. De-Jun, L. Qiang-Guo, L. Ai-Tao, Y. Li-Juan, J. Qian-Hong, and L. Yi

Abstract  

The product from reaction of samarium chloride hexahydrate with salicylic acid and Thioproline, [Sm(C7H5O3)2·(C4H6NO2S)]·2H2O, was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimetric analysis. The standard molar enthalpies of solution of [SmCl3·6H2O(s)], [2C7H6O3(s)], [C4H7NO2S(s)] and [Sm(C7H5O3)2·(C4H7NO2S)·H2O(s)] in a mixed solvent of absolute ethyl alcohol, dimethyl sulfoxide(DMSO) and 3 mol L−1 HCl were determined by calorimetry to be Δs H m Φ[SmCl3 δ6H2O (s), 298.15 K]= −46.68±0.15 kJ mol−1 Δs H m Φ[2C7H6O3 (s), 298.15 K]= 25.19±0.02 kJ mol−1, Δs H m Φ[C4H7NO2S (s), 298.15 K]=16.20±0.17 kJ mol−1 and Δs H m Φ[Sm(C7H5O3)2·(C4H6NO2S)]·2H2O (s), 298.15 K]= −81.24±0.67 kJ mol−1. The enthalpy change of the reaction

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$SmCl_3 \cdot 6H_2 O(s) + 2C_7 H_6 O_3 (s) + C_4 H_7 NO_2 S(s) = Sm(C_7 H_5 O_3 )_2 \cdot (C_4 H_6 NO_2 S) \cdot 2H_2 O(s) + 3HCl(g) + 4H_2 O(1)$$ \end{document}
((1)) was determined to be Δs H m Φ =123.45±0.71 kJ mol−1. From date in the literature, through Hess’ law, the standard molar enthalpy of formation of Sm(C7H5O3)2(C4H6NO2S)δ2H2O(s) was estimated to be Δs H m Φ[Sm(C7H5O3)2·(C4H6NO2S)]·2H2O(s), 298.15 K]= −2912.03±3.10 kJ mol−1.

Restricted access

Abstract  

The solid-state coordination reactions of lanthanum chloride with alanine and glycine, and lanthanum nitrate with alanine have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L-1 HCl solvent of these three solid-solid coordination reactions have been measured using an isoperibol calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies have been determined to be Δf H m θ[La(Ala)3Cl33H2O(s), 298.2 K]= -3716.3 kJ mol-1, Δf H m θ [La(Gly)3Cl35H2O(s), 298.2 K]= -4223.0 kJ mol-1 and Δf H m θ [La(Ala)4(NO3)3H2O(s), 298.2 K]= -3867.57 kJ mol-1, respectively.

Restricted access