Authors:L. Qian, M. Ma, J. Wei, D. He, and D. Cheng
Sequestration of radioactive nickel (63Ni2+) in fly ash coming from hospital wastes incineration plant by incorporating nano-goethite as a function of pH, particle size
and the ratio of solid and liquid was investigated under the batch leaching experiments. The synthetic nanogoethite was characterized
by X-ray diffraction (XRD), transmission electron microscopy (TEM) and specific surface area (SSA). The admired needle nanogoethite
was obtained in terms of XRD, TEM and SSA analysis. Approximate 5% of 63Ni2+ was desorbed from the nanogoethite/fly ash composite under the circum natural pH conditions. The ratio of solid to liquid
has little effect on desorption of 63Ni2+ from nanogoethite/fly ash composite. These results indicate that the radioactive nickel in fly ash can be sequestrated by
incorporating nanogoethite. The results may play significantly a role in immobilization in situ of trace radionuclides in
the natural environment.
The effect of itaconic acid (IA) content and heating rate on the stabilization reactions in poly(acrylonitrile-co-itaconic
acid) (P(AN-co-IA)) was investigated by differential scanning calorimetry (DSC) with peak-resolving method. Increasing IA
content was effective in decreasing the initial temperature and the heat evolved, and found to enhance oxidative reactions
to some extent. While, promoting heating rate resulted in a shift of the exotherm to a higher temperature and a more rapid
liberation of heat. The percentage of area of the first exothermic peak increased with increasing heating rate, which would
be attributed to the enhancement of the free radical cyclization reactions.
Authors:L. Wu, K. Chen, S. Cheng, B. Lee, and C. Shu
Hydrogen peroxide (H2O2) is popularly employed as a reaction reagent in cleaning processes for the chemical industry and semiconductor plants. By
using differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2), this study focused on the thermal decomposition
reaction of H2O2 mixed with sulfuric acid (H2SO4) with low (0.1, 0.5 and 1.0 N), and high concentrations of 96 mass%, respectively. Thermokinetic data, such as exothermic
onset temperature (T0), heat of decomposition (ΔHd), pressure rise rate (dP/dt), and self-heating rate (dT/dt), were obtained and assessed by the DSC and VSP2 experiments. From the thermal decomposition reaction on various concentrations
of H2SO4, the experimental data of T0, ΔH, dP/dt, and dT/dt were obtained. Comparisons of the reactivity for H2O2 and H2O2 mixed with H2SO4 (lower and higher concentrations) were evaluated to corroborate the decomposition reaction in these systems.
Authors:Hongfei Cheng, Jing Yang, Ray L. Frost, Qinfu Liu, and Zhiliang Zhang
The thermal behavior and decomposition of kaolinite–potassium acetate intercalation complex was investigated through a combination of thermogravimetric analysis and infrared emission spectroscopy. Three main changes were observed at 48, 280, 323, and 460 °C which were attributed to (a) the loss of adsorbed water, (b) loss of the water coordinated to acetate ion in the layer of kaolinite, (c) loss of potassium acetate in the complex, and (d) water through dehydroxylation. It is proposed that the potassium acetate intercalation complex is stability except heating at above 300 °C. The infrared emission spectra clearly show the decomposition and dehydroxylation of the kaolinite intercalation complex when the temperature is raised. The dehydration of the intercalation complex is followed by the loss of intensity of the stretching vibration bands at region 3600–3200 cm−1. Dehydroxylation is followed by the decrease in intensity in the bands between 3695 and 3620 cm−1. Dehydration is completed by 400 °C and partial dehydroxylation by 650 °C. The inner hydroxyl group remained until around 700 °C.
Authors:Zong Quan Wu, V. L. Dann, S. Z. D. Cheng, and B. Wunderlich
In an effort to find the limit of crystallization of polypropylene, a series of quantitative and semiquantitative DSC experiments at rates up to 10,000 deg/min are described. Even at these fast rates polypropylene crystallized on cooling between 350±15 K and 280±6 K. No “fully amorphous” polypropylene was produced. No initial stage crystallization to the condis state could be proven by quenching after partial crystallization.
Authors:Y. Wang, S. Feng, X. Feng, Y. Lei, L. Cheng, Q. Xu, Z. Zhuo, and D. Xue
Yaozhou Kiln at Lidipo and Shangdian are two independent porcelain kiln groups of Yaozhou kiln series in Shanxi Province.
Both of them were consisted of some individual porcelain kilns. The samples of 20 pieces of porcelain sherds produced in Shangdian
and 43 pieces of porcelain sherds made in Lidipo sites which produced in Kin Dynasty (1115–1234 A.D.) have been collected.
The main chemical compositions in body were determined by X-ray fluorescence (XRF). The contents of trace elements were measured
using neutron activation analysis (NAA). Principal component analysis (PCA) and stepwise discriminant analysis were used to
study the provenance characteristic of these samples. The results indicated that the main components and trace elements in
the specimen can be used to reveal the provenance characteristic.
Authors:Y. Q. Cheng, Y. X. Zhang, S. D. Qi, H. L. Chen, and X. G. Chen
1,7-Dihydroxy-3,8-dimethoxyxanthone (X1) and 1,8-dihydroxy-3,7-dimethoxyxanthone (X2) are two important xanthones of the Tibetan medicinal plant Gentianopsis paludosa (Hook. f.) Ma. They are very similar in structure, the only difference being exchange of OH and OCH3 at the 7 and 8 positions. By calculations based on the geometry of the molecules using the MM+ force field, the different distances between the hydroxyl groups of the two xanthones were obtained (4.64774 Å for X2 and 7.19412 Å for X1), therefore, the two hydroxyl groups of X1 should freely interact with more water molecules than those of X2 in aqueous solution. In other words, X2 is more hydrophobic than X1. Micellar electrokinetic capillary chromatography (MEKC) was therefore chosen for separation of the compounds. The optimum separation conditions were: 20 mm borate + 20 mm SDS (pH 9.8) as running buffer, 17.5 kV applied potential, and detection wavelength 260 nm. The two xanthones were well separated in 9.0 min, with Gaussian peak shapes. The repeatability of the MEKC method (expressed as RSD) for X1 and X2 was 0.9 and 1.1%, respectively, for migration time, and 3.1 and 1.4% for peak area. The limits of detection (S/N = 3) were 0.41 μg mL−1 for X1 and 0.82 μg mL−1 for X2. The recovery of the MEKC method for the two xanthones was also satisfactory.
Authors:L. Liu, T. Zhao, X. M. Cheng, C. H. Wang, and Z. T. Wang
Harmaline and harmine accounted for more than 70% in composition in extracts of P. harmala. More attention, however, should be paid to the other alkaloids which would be favorable or unfavorable to the efficacy and safety of the products. It was necessary to determine these trace alkaloids in the extracts; thereafter, most of them have been characterized. Diglycoside vasicine, vasicine, vasicinone, harmalol, harmol, tetrahydroharmine, 8-hydroxy-harmine, ruine, harmaline, and harmine were separated and identified with reference substances and characteristic MS spectra in extracts by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) and high-performance liquid chromatography (HPLC). Three trace alkaloids, vasicine, harmalol, and harmol were determined using the developed chromatographic separation method subsequently. The average contents of vasicine, harmalol, and harmol in extracts of ten batches were 2.53 ± 0.73, 0.54 ± 0.19, and 0.077 ± 0.03%, respectively. The total content of the three alkaloids was 3.23 ± 0.90% (from 1.81 to 4.48%). For rough estimation of all the relative alkaloids except of harmaline and harmine, the average total areas of all peaks in extracts varied from 4.35 to 26.64% detected at 220, 254, 265, 280, and 380 nm, respectively. The results indicated that area normalization method was powerless for the quality evaluation for traditional herb medicine consisting of numerous compounds with highly differential features. It might be concluded that LC-MS or HPLC could be utilized as a qualitative and quantitative analytical method for quality control of the extracts from seeds of P. harmala L.
Authors:W. Xue, A. Gianinetti, Y. Jiang, Z. Zhan, L. Kuang, G. Zhao, J. Yan, and J. Cheng
The cereal endosperm provides nutrients for seedling growth. The effects of seed components in seedling establishments under salt stress are, however, not yet fully explored. In this study, 60 barley recombinant inbred lines derived from Lewis × Karl cross were grown in four different environments, and the seed contents of starch, total soluble protein, phytate, total phenolics, total flavonoids and total inorganic phosphorus were determined in the harvested grains. Seeds of each line from the four environments were also assayed for seedling growth under saline treatments from 0 to 400 mM NaCl. Root and shoot lengths after 7 days decreased with increasing salt concentration. Correlations between seed components and either root or shoot length were established across the four seed sources. ANOVA showed a significant environment/source effect for both seed components and seedling growth, although the latter was less affected by the seed-production environment. Modeling seedling length across multiple salinities for each seed source showed that the environment with the most saline-tolerant root-growth curve was that associated the highest seed phosphorus content. Correlations between seed components and seedling growth traits highlighted phytate and total inorganic phosphorus as key components for seedling growth under moderate salinities. Seed phytate contents benefited seedling growth, even at high salinities, suggesting an additional role for this seed component under stressful growth conditions, possibly linked to its potential function as an osmolyte source.