The thermotropic phase transitions in the perovskite type layer compound (n-C10H21NH3)2MnCl4 and (n-C14H29NH3)2MnCl4 were synthesized and, at the same time, a series of their mixtures C10Mn-C14Mn were prepared. The experimental binary phase diagram of C10Mn-C14Mn was established by differential thermal analysis (DTA), IR and X-ray diffraction. In the phase diagram new material (n-C10H21NH3)(n-C14H29NH3)MnCl4 and two eutectoid invariants were observed, two eutectic points temperatures are about 29.8 and 27.9°C. Contrasting other
similar system, there are three noticeable solid solution ranges (α, β, γ) at the left and right boundary and middle of the
Thermal decomposition of potassium chlorate in the presence of various additives is studied using thermogravimetric analysis
and differential thermal analysis. Catalytic effects of metal oxides with comparable surface areas are compared, and the catalytic
effects of a number of nonoxide additives are also studied. The nonoxide additives show catalytic activities similar to the
corresponding metal oxides. Metal cations and their electron configurations determine the catalytic activity of various compounds.
Metal cations with partially filledd shells have the highest activity, transition metal cations with completely emptyd orbitals are moderated active, and metal cations with completely filledd shells or noble gas configurations have minimum activity.
As a consequence
of their excellent barrier properties vinyl chloride/vinylidene chloride copolymers
have long been prominent in the flexible packaging market. While these polymers
possess a number of superior characteristics, they tend to undergo thermally-
induced degradative dehydrochlorination at process temperatures. This degradation
must be controlled to permit processing of the polymers. Three series of N-substituted
maleimides (N-alkyl-, N-aralkyl, and N-aryl) have been synthesized, characterized
spectroscopically, and evaluated as potential stabilizers for a standard vinyl
chloride/vinylidene chloride (85 mass%) copolymer. As surface blends with
the polymer, these compounds are ineffective as stabilizers. However, significant
stabilization may be achieved by pretreatment of the polymer with N-substituted
maleimides. The most effective stabilization of the polymer is afforded by
N-aralkyl- or N-arylmaleimides, most notably, N-benzylmaleimide and N-p-methoxyphenylmaleimide.
The Taihang Mountain Range is located at E112°50′–114°30′, N35°20′–39°30′ in North China. This study aimed to reveal relationships between plant communities, soil variables and topographic variables. Floristic data and environmental data from sixty-eight quadrats of 10 m × 20 m along an elevation gradient from 1050 to 2180 m were analysed by TWINSPAN, DCA and CCA. Eight vegetation formations were recognized, all secondary successional stages following the original broad-leaved deciduous forests’ distraction by human activities. The results showed that the community patterns are related to both soil variables and topographic variables. Among the soil variables, soil N, P, K and organic matter were found to be the most important factors forcing the spatial patterns of plant communities. The vegetation patterns were also significantly correlated with the topographic variables, elevation, slope and aspect. Interactions between the environmental variables were significant. It is concluded that further measures for the conservation of vegetation and protection of soils in the Taihang Mountains must be undertaken.
The complexes of [Sm(o-MOBA)3bipy]2·H2O and [Sm(m-MOBA)3bipy]2·H2O (o(m)-MOBA = o(m)-methoxybenzoic acid, bipy-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, IR, UV, XRD and
molar conductance, respectively. The thermal decomposition processes of the two complexes were studied by means of TG–DTG
and IR techniques. The thermal decomposition kinetics of them were investigated from analysis of the TG and DTG curves by
jointly using advanced double equal-double steps method and Starink method. The kinetic parameters (activation energy E and pre-exponential factor A) and thermodynamic parameters (ΔH≠, ΔG≠ and ΔS≠) of the second-step decomposition process for the two complexes were obtained, respectively.
Heat capacities of both the ingot-like and melt-spun Al-Sr alloys have been measured through the temperature range 373 to
1060 K using differential scanning calorimetry. The experimental results show that rapid solidification has a slight effect
on the temperature dependence of the heat capacities of the Al-Sr alloys. The heat capacities of the melt-spun Al-Sr alloys
increase more slowly than those of the ingot-like alloys with increasing temperature from 373 to 900 K. Furthermore, the effect
of rapid solidification on the heat capacities becomes more obvious with increasing Sr concentration in the Al-Sr alloys.
The data of the heat capacities between 373 and 900 K have been fitted with the least square method and a linear dependence
on temperature was assumed for that temperature range.
Chlorophyll content is positively correlated with photosynthetic rate. However, little is known about the genetic correlation between grain yield and chlorophyll content in the same wheat mapping population. The primary goal of the study was to detect the genetic basis of grain yield and chlorophyll content and their possible roles in the genetic improvement of grain yield in wheat. Here, quantitative trait loci (QTLs) for grain yield and chlorophyll content were studied using a set of 168 doubled haploid (DH) lines derived from a cross between two elite Chinese wheat cultivars, Huapei 3×Yumai 57. The DH population and parents were evaluated for grain yield and chlorophyll content in three environments. A total of 11 additive QTLs and 6 pairs of epistatic QTLs were detected for grain yield and chlorophyll content. Loci, such as
on chromosomes (e.g. 2D, 4A, and 5D) simultaneously controling grain yield and chlorophyll content, showed tight linkages or pleiotropisms. Three novel major QTLs,
, closely linked with the PCR marker
on chromosome 5D, accounted for 10.32%, 12.95%, and 23.29% of the phenotypic variance, respectively. The favorable alleles came from Yumai 57.
High-performance capillary electrophoresis with amperometric detection (CE-AD) has been used for analysis of eight bioactive components of the leaves, stems, and roots of Valeriana wallichii DC, after a relatively simple extraction procedure with ethanol. Under the optimum conditions, the eight components can be well separated or (apigenin and luteolin) separated nearly to baseline within 23 min by use of 50 mM borax (pH 9.2) as running buffer and a separation potential of 16 kV. Linearity was excellent over two orders of magnitude of concentration and detection limits (S/N = 3) ranged from 1.7 × 10−7 to 1.8 × 10−8 g mL−1. This method was used for comparison of the concentrations of the bioactive compounds in different parts of the plant on the basis of their electropherograms or ‘characteristic electrochemical profiles’. Assay results were satisfactory.
Authors:J. Fan, S. Zhang, J. Lu, J. Liu, X. Zhang, Y. Ding, and Y. Chang
In order to measure 182Hf by accelerator mass spectrometry (AMS), a chemical procedure for separation of hafnium from tungsten has been developed
by extraction chromatography. The extraction chromatographic behavior of hafnium and tungsten has been studied using tri-n-octylamine (TOA) as the stationary phase, HCl–H2O2 mixture and NH3·H2O as the mobile phase. The effects of H2O2 concentration, column loading and column dimensions are investigated. Hf and W with microgram amounts are successfully separated
on a chromatographic column (Ø5 × 196 mm), on which Hf is hardly retained after completely eluted with 6 M HCl–1% H2O2 and W strongly adsorbed is then eluted with 3 M NH3·H2O. The decontamination factor for tungsten is 3.0 × 105 and the recovery of hafnium is better than 99% using a single column separation.
Authors:F. Zhang, J. Li, X.L. Wang, W. Mao, H. Zhang, J. Guo, and J.W. Li
An allometric analysis of biomass and N mass allocation of rice (Oryza sativa L.) seedlings under non-shaded (100% of full sunlight) and shaded (30% of full sunlight) treatments were conducted. The allometric slopes and the intercepts were estimated using standardized major axis regression. Results indicated that biomass was preferentially allocated to stems during plant ontogeny, and leaves and roots were isometric when rice seedlings were not shaded. Under shade, however, more biomass was allocated to leaves and stems. N mass allocation was also altered by shading in that more N mass was allocated to the aerial shoots, and plants accumulated less N mass when shaded. Our study revealed that both biomass and N mass were in accordance with the optimal partitioning theory.