Authors:N. Dragoe, K. Nakahara, L. Xiao, H. Shimotani, and K. Kitazawa
The thermal decomposition of methano-fullerene derivatives such as ethoxycarbonyl methano fullerene and various isomers
of bis-(ethoxycarbonyl methano) fullerene leads to new fullerene derivatives, which have been preliminary characterized.
The analysis of separated species was performed by UV-VIS, IR, H- and C-NMR, STM, FAB, LDI and MALDI-TOF MS spectroscopy.
One of the isolated phases is a C122 molecule with a dumbbell-like structure.
Authors:Z. Zhang, Y. Wang, F. Li, H. Xiao, and Z. Chai
The contents of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in various plant species taken from a rare earth ore area were determined by instrumental neutron activation analysis. For a given plant, the REE patterns in root, leaf and host soil are different from each other. The REE distribution characteristics in roots of various species are very similar and resemble those in the surface water. The results of this study suggest that there is no significant fractionation between the REEs during their uptake by the plant roots from soil solution. However, the variation of the relative abundance of individual REE occurs in the process of transportation and deposition of REEs in plants.
The aim of this study is to investigate the melting/freezing characteristics of paraffin by adding Cu nanoparticles. Cu/paraffin composite phase change materials (PCMs) were prepared by a two-step method. The effects of Cu nanoparticles on the thermal conductivity and the phase change heat transfer of PCMs were investigated by the Hot Disk thermal constants analyzer and infrared monitoring methods, respectively. The maximum thermal conductivity enhancements up to 14.2% in solid state and 18.1% in liquid state are observed at the 2 wt% Cu/paraffin. The photographs of infrared monitoring suggest that the melting and freezing rates of Cu/paraffin are enhanced. For 1 wt% Cu/paraffin, the melting and freezing times can be saved by about 33.3 and 31.6%, respectively. The results provide that adding nanoparticles is an efficient way to enhance the phase change heat transfer of PCMs.
Authors:F. Wang, H. Fan, D. Chen, H. Bai, Z. Chen, and L. Xiao
Radiolabeled somatostatin analogue is a useful ligand for scintigraphic imaging of somatostatin receptor-bearing tumors. In
this study, we investigated the effects of different radiolabeling conditions on labeling yield and ratio between mono-iodinated
and di-iodinated125I-Tyr3-octreotide by HPLC analysis. In vitro and in vivo stabilities of125I-Tyr3-octreotide and111In-DTPA-D-Phe1-octreotide were also determined. Both radiolabeled compounds were relatively stable in vitro, but were decomposed to free125I− and111In-DTPA in vivo, respectively.
Authors:J. Li, W. Dai, G. Xiao, H. Wang, Z. Zhang, and T. Wu
99Tc is an important radionuclides related to repository safety assessment. The mobility pertechnetate (TcO4−) can be reduced to immobility technetium(IV) hydrous oxides (TcO2·nH2O) by Fe(II)-bearing minerals. In China, Gaomiaozi (GMZ) bentonite is regarded as the favorable candidate backfilling material
for the HLW repository, which is contained some FeO. The diffusion behavior of 99Tc was investigated in GMZ bentonite by through- and out-diffusion methods. The effective diffusion coefficient (De), the accessible porosity (εacc), apparent diffusion coefficient (Da) and distribution coefficient (Kd) were decreased with the increasing of dry density. The De values were (2.8 ± 0.2) × 10−11 m2/s and (3.5 ± 0.2) × 10−12 m2/s at dry density of 1,600 and 1,800 kg/m3, respectively. It was indicated that the dominating species was TcO4− during the diffusion processing. While, out-diffusion results showed that part of TcO4− may be reduced by Fe(II). The relationship of De and εacc could be described by Archie’s law with exponent n = 2.4 for 99Tc diffusion in GMZ bentonite. Furthermore, the relationship between Da and dry density (ρ) was exponential.
Authors:S. Ma, C. Chai, X. Mao, H. Peng, K. Lu, X. Xiao, and Z. Ouyang
Chemical elemental compositions of some silicate, magnetic and glass spherules were investigated with INAA. The elements determined include Os, Ir, Ni, Co, Fe, Cr, Au, La, Ce, Sm, Eu, Yb, Lu and Sc etc. The elemental correlation, as well as their enrichment (or depletion) factors relative to Cl chondrite were examined. The high concentrations of the refractory siderophile elements contained in these spherules support the proposal that they originate from extraterrestrial substances. Some useful chemical criteria for identifying the sources of silicate, magnetic and glass spherules are put forward.
Authors:H.-L. Liu, S.-J. Liu, Z.-L. Xiao, Q.-Y. Chen, and D.-W. Yang
Excess molar enthalpies of binary mixtures for tributyl
phosphate (TBP)+methanol/ethanol were measured with a TAM air Isothermal calorimeter
at 298.15 K and ambient. The results for xTBP+(1–x)CH3OH
are negative in the whole range of composition, while the values for xTBP+(1–x)C2H5OH
change from positive values at low x to
small negative values at high x. The experimental
results have been correlated with the Redlich–Kister polynomial. IR
spectra of the mixtures were measured to investigate the effect of hydrogen
bonding in the mixture.
Authors:Y. Xu, S. Zhang, H. Ding, X. Lu, W. Yang, S. Yuan, Y. Xiao, and Y. Niu
The neutron-rich target-like isotope 236Th has been produced in the 238U-2p multinucleon transfer reaction between a 60 MeV/u 18O beam and natural 238U targets. The activities of thorium were determined after radiochemical separation of Th from the mixture of uranium and
reaction products. The 236Th isotope was identified by the characteristic γ-rays of 642.2, 687.6 and 229.6 keV. The production cross section of 236Th was determined to be 250±50 μb.
Authors:Z. Zhang, F. Li, L. Xu, N. Liu, H. Xiao, and Z. Chai
Chemical behavior of lanthanum in root tips excized from wheat seedlings growing at both promotional and inhibitory levels of LaCl3 in culture solutions was investigated by a sequential leaching procedure combined with instrumental neutron activation analysis. The results indicate that most of La exists in non-exchangeable species and the binding of La3+ to the root tips is extremely stable. The root tips during growing at the inhibitory level of LaCl3 absorb much more La than those at the promotional level. However, the La proportion in each fraction is similar for both groups.
Authors:F.-Y. Du, X.-H. Xiao, P.-P. Xu, and G.-K. Li
An efficient ionic liquid-based microwave-assisted (IL-MAE) method has been developed for extraction of dehydrocavidine from Corydalis saxicola Bunting (C. saxicola) for subsequent rapid analysis by high-performance liquid chromatography (HPLC). The yield of dehydrocavidine reached 9.446 mg g−1 within 10 min under the optimum IL-MAE conditions (1.5 mol L−1 [hmim]Br as extraction solvent, liquid-to-solid ratio 20:1 (mL:g), and extraction temperature 70°C). Compared with conventional procedures, the proposed IL-MAE method has many advantages, for example high extraction yield, short extraction time, low solvent consumption, no use of volatile organic solvents, and no further sample clean-up before HPLC analysis. The method was validated for limit of detection (LOD) and quantification (LOQ), linearity, precision, recovery, and reproducibility. The calibration range was 5.0–200 mg L−1 and the correlation coefficient, r, was 0.9996. The LOD and LOQ were 0.035 and 0.12 mg L−1, respectively. The relative standard deviations of intra-day and inter-day assays were below 2.6% and 6.5%, respectively. Recovery was between 93.8% and 109.3% with RSD values below 5.0%. The method can be used for rapid and effective extraction and analysis of active components from medicinal plants.