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- Author or Editor: X. Wang x
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Abstract
The decomposition kinetics of reference calcite and three ultra-fine samples with different morphologies are investigated. The kinetic parameters and rate equation are obtained according to the methods reported in our previous studies. Compared with the reference calcite, a considerable diminution of the activation energy E a up to 70–80 kJ mol−1 is observed in the case of three ultra-fine samples. There are also some distinct differences concerning the activation energy of each of the ultra-fine sample. This may have something to do with the particle morphology revealed by TEM and SEM measurements. XRD measurements of four calcite samples show that large strain exists in the crystal lattice in the case of ultra-fine calcite samples. This may give a reason to their abnormal decomposition behavior.
Abstract
Zirconium in simulated high level radioactive liquid waste (HLLW) was selectively adsorbed and separated by self-made high adsorption activity silica gel. The selective adsorption mechanism was analyzed according to the structure character of self-made silica gel and performance of zirconium in acid simulated HLLW. The results show that the adsorption selectivity of self-made silica gel for zirconium is strong, because zirconium has higher positive charge and zirconium ion hydrolyzes easily. Distribution coefficient of self-made silica gels for zirconium is 53.5 ml/g. There are 6.5 (OH)/nm2 on the surface on self-made silica gels which provide more adsorption activity places, thus self-made silica gels have higher adsorption capacity for zirconium (31.4 mg/g). The elution rate of the adsorption of zirconium on self-made silica gel by 0.2 mol/l H2C2O4 is more than 99%. The solubility of the self-made silica gel in nitric acid is low, the chemical stability of self-made silica gel is very strong.
Abstract
A new ecomaterial, zirconyl molybdopyrophosphate (ZMPP), was prepared by a coprecipitation method. The removal of Cs+ and Sr2+ ions from simulated strong acid HLLW using the ion exchange process on ZMPP had been investigated. It showed that there are more than 90% Cs+ and Sr2+ removed from the simulated HLLW on ZMPP despite the presence of other metal ions, such as Na+, Al3+, Fe3+, etc. in excess. Then ZMPP may likely be a selective ion exchanger for the removal of 137Cs and 90Sr directly from strong acid HLLW.
Abstract
An Al2(WO4)3 target bombarded with a proton beam (28.5 MeV, 20 
A) for 1 hour was completely dissolved in about 5 ml of hot 2N NaOH and the clear solution was neutralized with 2N HCl. The resulted white precipitate of Al2(WO4)3 can be separated from the solution by centrifugation and decantation. The supematant containing radioactive Re as ReO
4
–
was loaded onto a column (1 cm×10 cm) of activated alumina (100–200 mesh). Eluted with 10 ml of saline, the carrier-free ReO
4
–
was collected, while the small amount of Al2(WO4)3 in the supematant was adsorbed on the column. The total yield of ReO
4
–
was 94.7% and the breakthrough of WO
4
2–
, only 1.0·10–6 M. The whole separation process can be accomplished within 30 minutes. This rapid and efficient Re/W separation protocol is applicable to the preparation of carrier-free186Re, when an enrichel Al2(186WO4)3 target is used.
Abstract
A total reflection X-ray fluorescence (TXRF) analyzer with a special structure is described. Its short X-ray path (about 15 cm) resulted in a high sensitivity, low power consumption and small volume. The structure with double total reflection path is suitable for easy change of exciting source to cover a large element range. The minimum detection limit (MDL) of 6 pg for Co under Cu exciting source and 22 pg for Sr under Mo tube. Some significant works were done, such as the detemination of sulfur content in fuel oils, the non-destructive analysis of an ancient bronze utensil and the regular analysis of tap water.
Eight cultivars of dry-land wheat (Triticum aestivum L.) historically planted in Shaanxi Province, China, were grown in plots with irrigation and drought treatments during the growing seasons of 2011–2014, so as to characterize the differences in the rate and duration of the grain-filling stage among cultivars. The experimental results showed no obvious change among cultivars with respect to the duration of the grain-filling stage and no significant correlation between duration and grain weight. The filling rates of all three phases (lag, linear, and mature periods) showed significant differences among cultivars and had a greater effect on the grain weight than the duration of the filling stage, even though drought decreased the filling rate in the linear and mature periods. A lower filling rate led to a lighter grain weight in inferior grains than in superior grains. For the superior and inferior grains in the central spikelets, modern cultivars possess faster filling rates, especially in the lag and linear periods, whereas for the whole spike, no significant trend with cultivar replacement was observed. Faster filling rates with stable filling durations will be beneficial in obtaining additional yield increases.
Cytomixis has been described in many plant species, but not in Thinopyrum . The present study reports spontaneous cytomixis during microsporogenesis in Thinopyrum intermedium (2n = 42), Thinopyrum ponticum (2n = 70), and their F 1 hybrids with wheat. Cytomixis frequently occurred in early prophase I but very rarely in meiosis II. The type of cytomixis that occurred most often was where chromatins migrate from one nucleus into an adjacent cel1. Migration from one nucleus into two or more cells or from two or more nuclei into one cel1 was also observed. After a donor cell transferred chromatin to a recipient cell, the recipient cell would sometimes pass the chromatin on to another cell. Migration did not necessarily occur between cells in the same stage. Cytomixis in Th. ponticum and its hybrids with wheat was more complex than that in Th. intermedium . The possible causes, cytological consequences and genetic significance of cytomixis are discussed.
Field cultivation practices affected soil temperature that influenced the crop development of winter crops. This study was undertaken to determine the effects of different mulch materials, tillage depths and planting methods on spike differentiation of winter wheat ( Triticum aestivum L.). The field experiment was consisted of three tests: (i) polythene mulch, straw mulch and no mulch; (ii) ridge planting and furrow planting; (iii) conventional tillage and shallow tillage. The results showed that soil temperature was affected by different practices. The higher soil temperature under polythene mulch resulted in the earlier initiation of spike differentiation, while straw mulch decreased soil temperature in spring that delayed the initiation compared with the non-mulch treatment. The spike initiation under ridge planting started earlier than that of furrow planting. Reduced tillage delayed the initiation compared with the conventional tillage. Duration of spike differentiation lasted longer under earlier starting of initiation that increased the grain numbers per spike. Other yield component characters were not affected by soil temperature. It was concluded that in the North China Plain where grain-filling duration of winter wheat was limited, agricultural practices that increased soil temperature in spring were favorable for grain production.
Among the progenies of crossing Triticum turgidum — Haynaldia villosa amphiploid with synthetic hexaploid wheat (T. carthlicum / Aegilops tauschii) Am3, two lines (SN030713 and SN05078), with good resistance to stripe rust and powdery mildew, were developed. Cytological studies demonstrated that SN030713 contained 42 chromosomes and formed 21 bivalents at meiotic metaphase I. SN05078 contained 28 chromosomes and formed 14 bivalents. Genomic in situ hybridization analysis using H. villosa V genomic DNA as the probe showed SN030713 and SN05078 had no large H. villosa chromosome fragments. PCR analysis with H. villosa specific primer pHv29 showed that H. villosa genetic materials were introgressed in these two lines. SSR analysis indicated that the genomic composition of SN030713 was 2n = 6x = 42 (AABBDD), and SN05078 was 2n = 4x = 28 (AABB). Introgressed Ae. tauschii genetic materials in SN05078 were also detected.
Abstract
N,N,N',N'-Tetrabutyladipicamide (TBAA) was used for the extraction of nitric acid and uranyl(II) ion from nitric acid media into toluene. The effects of nitric acid, uranyl(II) ion, and extractant concentration, temperature and back extraction on the distribution coefficient of uranyl(II) ion have been studied. The main adduct of TBAA and HNO3 is TBAA·HNO3 in 1.0 mol/l nitric acid solution. The 1:2:2 complex of uranyl(II) ion, nitrate ion and TBAA as extracted species is further confirmed by IR spectra of the extraction of uranyl(II) ion with TBAA. The values of the thermodynamic parameters have also been calculated.
