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Abstract  

The combustion behavior of Shuangya Mountain (SYM) coal dust has been investigated by means of TG in this paper. The reaction fraction can be obtained from isothermal TG data. The regressions of g(), an integral function of vs. t for different reaction mechanisms were performed. The mechanism of nucleation and nuclei growth is determined as the controlling step of the coal dust combustion reaction by the correlation coefficient of the regression, and the kinetic equation of the SYM coal dust combustion reaction has been established.

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Abstract  

Two series of antibacterial compounds were synthesized using montmorillonite and chlorhexidine acetate (CA) by ion-exchange reaction. The resulting samples were characterized by high-resolution thermogravimetric analysis (HRTG), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and their antibacterial activity was assayed by halo method. In this study, the loaded amounts of CA in the resultant compounds were evaluated by the HRTG curves. CA adopts a lateral monolayer arrangement in the resulting samples with low CA loading, while a special state with partial overlapping of organic molecules is supposed for the resulting samples prepared at 1.0–4.0 CEC. After the intercalation with CA, the hydrophilic surfaces of montmorillonite are changed to hydrophobic ones, reflected by the frequency shift of the symmetric ν1(O-H) stretching vibration from low to high. This study shows that the interlayer cations in raw montmorillonite have little influence on the structure of the resulting samples. Antibacterial activity test against E. coli demonstrates that the antibacterial activity of the resulting samples strongly depends on the content of the loaded CA and these resulting materials show a long-term antibacterial activity that can last for at least one year.

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Abstract  

Supramolecular 2,3- and 2,5-pyridinedicarboxylate (PDC) intercalated ZnAl-layered double hydroxides (2,3- and 2,5-PDC–ZnAl–LDHs) have been prepared by ion exchange method. The structure and composition of the intercalated materials have been studied by X-ray diffraction (XRD) and inductively coupled plasma emission spectroscopy (ICP). The study indicates that the 2,3-PDC and 2,5-PDC anions are accommodated as interdigitated bilayer and monolayer arrangement respectively between the sheets of LDHs. Furthermore, their thermal decomposition processes were studied by the use of in situ high temperature X-ray diffraction (HT-XRD), and the combined technique of thermogravimetry-differential thermal analysis-mass spectrometry (TG-DTA-MS) under N2 atmosphere. Based on the comparison study on the temperatures of both decarboxylation and complete decomposition of interlayer PDC, it can be concluded that 2,5-PDC–ZnAl–LDHs has higher thermal stability than that of 2,3-PDC–ZnAl–LDHs.

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The geographical patterns of tree species richness in forest communities have been studied widely, but little is known about the geographical variation of the estimated species richness and minimum areas using species-area curves. A differential technique based on the species-area relationships (SAR) was developed for estimating the minimum area (Amin) capturing 60- 80% of the species in each plot, which is an important characteristic of a forest community. The relationship between estimated species richness (ESR) from the SAR and the corresponding minimum area is described by the linear model ESR = 0.0051×Amin (R2 = 0.98, p < 0.0001). Both the ESR and the minimum area exhibit similar geographical variations with a significant increase along altitudinal and a decrease along latitudinal gradients. The spatial variations of the ESR were partitioned into three geographical components and their combined effects. Altitude accounted for 40% and 45% of the total variation in the ESR and the minimum area, respectively. While latitude accounted for 69% and 61% of the total variation in the ESR and the minimum area, respectively. Thus, latitude is the main determinant which influences the geographical variation of the ESR. As far as we know, this study presents the first report of the geographical patterns of the minimum area in temperate forests.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Ch. He, E. Hamada, T. Suzuki, H. Kobayashi, K. Kondo, V. Shantarovich, and Y. Ito

Abstract  

A new pulsed mono-energetic slow positron beam as well as the conventional positron annihilation lifetime spectroscopy (PALS) have been applied to study the sub-surface and the bulk of epoxy polymer. Significant changes of o-Ps parameters were found at a short distance from the surface. The lifetime of o-Ps was observed to decrease with increasing the positron implantation depth, while its intensity increased. The temperature effect on o-Ps parameters at sub-surface was also investigated. The glass transition temperature for the sub-surface was lower than that for the bulk. Furthermore, the thermal expansion coefficient of the sub-surface was found smaller than that of the bulk.

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Abstract  

A series of anion-cation surfactants modified organoclays are prepared by incorporating both cationic surfactant, hexadecyltrimethylammonium bromide (HDTMAB), and anionic surfactant, sodiumdodecyl sulfonate (SDS), to montmorillonite. The added amounts of surfactant varied from 0.2 to 4.0 CEC of the used montmorillonite, similar to those reported in literature. A combination of elemental analysis, X-ray diffraction and thermogravimetric analysis is used in the characterization of the resulting organoclays. The experimental results show that anionic surfactants can not be intercalated into the montmorillonite whereas they can be loaded onto cationic modified montmorillonite, resulting in a further increase of organic carbon content of the resulting organoclays. This study demonstrates that SDS can be intercalated into montmorillonite interlayer space through the interaction with HDTMAB rather than by ion exchange. The intercalation of SDS results in an increase of the basal spacing of the resulting organoclays when comparing with HDTMAB modified montmorillonite and higher decomposition temperature of the intercalated surfactants when comparing with them in bulk state. These new insights are of high importance in the application of organoclays in the fields of remediation of polluted water and synthesis of clay based nanocomposites.

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Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most serious diseases of wheat ( Triticum aestivum L.) worldwide. Of 94 Triticum durum/Aegilops tauschii synthetic wheat accessions tested, CI142 (Garza/Boy// Ae. squarrosa 271) was found to be resistant to 6 Chinese PST races. The resistance to stripe rust in CI142 was proven to be controlled by a single dominant gene, tentatively designated YrC142 . Gene postulation showed that the pathogenic specificity of CI142 is different from 21 other lines possessing known resistance genes, such as Yr10, Yr15, Yr24 , and Yr26 , located on chromosome 1B. Bulked segregant analysis (BSA) and F 2 segregation analysis of the CI142/Mingxian 169 cross were used to analyse the SSR markers linked to YrC142 . Five SSR markers were found to be closely associated with YrC142 in the order Xwmc419-YrC142-Xgwm273, Xbarc187-Xgwm18-Xwmc626 , in which the relative genetic distances of these SSR loci to the gene YrC142 were 5.4, 0.8, 0.8, 1.0, and 2.4 cM, respectively. Two SSR markers ( Xgwm273 −162 and Xgwm18 −168 ) distinguished YrC142 from Yr10, Yr15, Yr24 , and Yr26 , suggesting that these 2 SSR markers may be used as diagnostic ones for the gene in a wheat breeding program against stripe rust. Based on these findings, YrC142 is most likely a new gene or a new allele at the Yr26 locus, which provides an opportunity to diversify stripe rust-resistant resources for wheat breeding programs.

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Abstract

Bis(1-octylammonium) tetrachlorocuprate (1-C8H17NH3)2CuCl4(s) was synthesized by the method of liquid phase reaction. The crystal structure of the compound has been determined by X-ray crystallography. The lattice potential energy was obtained from the crystallographic data. Molar enthalpies of dissolution of (1-C8H17NH3)2CuCl4(s) at various molalities were measured at 298.15 K in the double-distilled water by means of an isoperibol solution-reaction calorimeter, respectively. In terms of Pitzer's electrolyte solution theory, the molar enthalpy of dissolution of (1-C8H17NH3)2CuCl4(s) at infinite dilution was determined to be and the sums of Pitzer's parameters and were obtained.

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Abstract  

To investigate the effects of lanthanum exposure on regional distribution of inorganic elements in rat brain. Wistar rats were exposed to lanthanum chloride through oral administration at 0, 0.1, 2, and 40 mg/kg concentration for 6 months. The elements such as Cl, K, Ca, Fe, Cu, and Zn were identified in the brain slices by synchrotron radiation X-ray fluorescence (SRXRF) analysis. Differences of brain elemental distributions were noticed. Cl, Ca, and Zn were primarily concentrated in hippocampus of the controls. With the increase of the lanthanum dosage, the Ca and Zn levels significantly decreased, while the Cu levels significantly elevated in cortex, hippocampus and thalamus. Our results suggest that subchronic lanthanum exposure in rats appears to change elemental distributions in brain.

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