Dai Yaodong

Effects of WO3 Particle Size in WO3/Epoxy Resin Radiation Shielding Material

To verify the influence of the functional elements particular size for the radiation attenuation coefficients and mechanical properties radiation shielding material based on epoxy resin, we prepare two WO3/E44 samples with different particular sizes of WO3 by a solidified forming approach. The linear attenuation coefficients of these samples are measured for γ-ray photo energies of 59.6, 121.8, and 344.1 keV, etc. using narrow beam transmission geometry. It is found that the linear attenuation coefficients would increase with the decreasing particle size of the WO3 in the epoxy resin based radiation shielding material. The theoretical values of the linear attenuation coefficients and mass attenuation are calculated using WinXcom, and good agreements between the experimental data and the theoretical values are observed. From the studies of the obtained results, it is reported that from the shielding point of view the nano-WO3 is more effective than micro-WO3 in the epoxy resin based radiation shielding material.

Using Gamma-Radiation for Drug Releasing from MWNT Vehicle

A drug delivery system via multi-walled carbon nanotube (MWNT) vehicle was synthesized in aqueous solution. MWNTs were first noncovalently functionalized with chitosan oligomers (CS) with a molecule weight of 4000?6000, making MWNTs water-soluble, and then a cancer ancillary drug tea polyphenols (TP) was conjugated mainly via the hydrogen bond between CS and TP molecules, making MWNTs efficient vehicle for drug delivering. The release of drug molecules can be realized by pH variation and ?-radiation, leading to new methods for controlling drug release from carbon nanotubes carrier. Due to the high penetrability of ?-rays, ?-radiation shows up new opportunities in controlled drug release, possibly facilitating the future cancer treatment in vivo.

Mössbauer Investigation of the Ferromagnetic Coupling in Copper-Iron Polycyanides

One of the Prussian blue analogs, molecular magnet CuII3[FeIII(CN)6]211.6H2O, was investigated by Mossbauer spectroscopy. It was found that transition temperature was around TC = 18.5 K from paramagnetic phase to ferromagnetic phase. The β value of the critical exponent is around 0.338 at magnetic ordering temperature. Therefore, the ferromagnetic coupling interaction of Cu-Fe cyanide could be clearly explained by spin wave theory.

Magnetic Behaviour of Iron Oxychloride and Its Organometallic Intercalation Compounds Studied by Mössbauer Spectroscopy

Metallocene intercalate compounds with iron oxychloride, FeOCl(FeCp2)0.16 and FeOCl(CoCp2)0.36 with Cp being cyclopentadienyl group, are synthesized and characterized. Magnetism and the structure–property relations are investigated by magnetic measurement and 57Fe Mossbauer spectroscopy. The results show that the through-space dipolar interactions play a critical role in three-dimensional magnetic ordering of such layered compounds.

Synthesis and Magnetic Properties of the Intercalation Compound FePS3 (CoCp2)0.40

Intercalation compound FePS3 (CoCp2)0.40 (CoCp2 = cobaltocene) was synthesized, and the crystal structure and magnetic properties were studied by x-ray diffraction, magnetic susceptibility measurement, and Mossbauer spectroscopy. The crystal structure was indexed to monoclinic unit cell with a = 5.996 A, b = 10.106 A, c = 12.511 A, β = 105.916 degrees, and about 5.6 A expansion at the c-direction compared to pure FePS3. The Mossbauer spectra indicate that there are three kinds of divalent ions with high spin state in the intercalation compound, which implies charge transfer from guest to the Fe–S eg* anti-bonding orbits of the host lattice. No cationic vacancies are formed in the intercalation compound. The ferromagnetism at low temperature originates from the spin canting of divalent ions.

A M?ssbauer study of the magnetic coupling in iron phosphorous trisulfides

The polycrystalline sample of layered compound FePS3 has been investigated by using Mossbauer spectroscopy (12K to 300K), magnetic susceptibility measurements, x-ray diffraction and FTIR spectroscopy. The antiferromagnetic order exists below TN=120.5±1K. The Mossbauer spectra below TN indicate that the magnetization axis is perpendicular to the layer of {FePS}3 and the divalent iron cations are in their high spin configurations. By fitting the hyperfine field parameters near the Neel temperature, we obtain information on the nature of magnetic interactions in the material. The results show that the magnetic coupling can be treated by the two-dimensional Ising model and it can be interpreted on the basis of a crystal-field effect.