Seasonal changes of progesterone content (PSC) in hair of three female giant pandas and testosterone content (TSC) in hair of two male giant pandas were tested. It was found that the two hormones could be detected by radioimmunoassay in all the hair samples scissored from the female and male giant pandas respectively. During March to early June, PSC in two non-pregnent giant pandas (x¯ ± SD = 13.40 ± 10.06 and 10.60 ± 8.88 ng / g hair respectively) were higher than those in non-breeding season (3.07 ± 1.07 and 3.20 ± 1.15 ng / g, P<0.01). PSC in a 18-year-old female giant panda remained at low levels (2.72 ± 1.49 ng / g) during March to December. In a twin-bear giant panda, PSC (6.77 ± 3.66 ng / g) appeared higher than that in non-pregnant giant pandas in non-breeding season. Around February to the end of May, TSC in two male giant pandas (1.89 ± 1.71 and 1.82 ± 1.04 ng / g respectively) were also higher than that in non-breeding season (0.98 ± 0.57 and 0.75 ± 0.39 ng / g, P<0.01). The findings from the study implied that giant panda's hair is possible to be used as a specimen to carry out steroids research in the endangered species.

The fate of CR formulation of ¹⁴C-thiobencarb (thio.) was studied at the high rate of application in a model paddy field. Thio. could be released from the alginate formulation (TAL-17189) into water. The concentration of thio. in water increased with time, then declined. Thio. in water could be converted to more than 12 ¹⁴C-degradation products which changed with time. An unknown degradation product (M_o) was always prevailing after application. Thio. in water could be adsorbed by soil particles. Most of the adsorbed thio. retained in upper layer. Thio. in soil could be also degraded to more than 6 products. Thio. and its degradation products could conjugate with the compositions of soil to bound residues (BR). Thio. was 45.6% of the total ¹⁴C-extractable residues (ER) in upper layer soil at harvest. ¹⁴C-thio. in water and soil could be uptaken by rice plants. Thio. in plants existed in ER and BR. Most of ¹⁴C-residues in straw, roots, brown rice and husk were in bound form, more than 92% of the total ¹⁴C in them at harvest respectively. Thio. in plants could be metabolized to more than 9 metabolites which changed with time. ¹⁴C-thio. in straw, brown rice and husk accounted for 55.88, 6.06 and 11.18% of the total ¹⁴C-ER of them at harvest respectively. An unknown ¹⁴C-metabolite in brown rice was prevailing, accounted for 63.03% of the total ¹⁴C-ER.

The study of paper damage under bombardments of protons and X-rays is reported. An on-demand beam pulsing system is useful for the PIXE analysis of delicate objects. IXX (or PIXE-induced XRF) is more suitable than PIXE in terms of damage to the sample. Some new PIXE and IXX applications of archaeological paper-like samples in recent years are given.

The positron lifetime spectra and electrical conductivities have been measured for polyaniline as a function of protonation level ([H⁺] from 10^-7—10^0.8 mol/L). We observed that (1) the short lifetime τ₁, which was related to electron density in bulk, decreased with the protonation level; (2) the intermediate lifetime τ₂≈360ps, almost remaining constant, whereas its intensity I₂ increased with increasing protonation level which was related to the conductivity of material. These results are discussed in terms of conducting island model.

The methods of determining the superficial absorbed dose distributions in a water phantom by means of the experiments and available theories have been reported. The distributions of beta dose were measured by an extrapolation ionization chamber at definite depthes corresponding to some superficial organs and tissues such as the radiosensitive layer of the skin, cornea, sclera, anterior chamber and lens of eyeball. The ratios among superficial absorbed dose D (0.07) and average absorbed doses at the depthes 1,2,3,4,5 and 6 mm are also obtained with Cross's methods. They can be used for confining the deterministic effects of some superficial tissues and organs such as the skin and the components of eyeball for weakly penetrating radiations.

Temperature dependence of the hyperfine field of Fe nanocrystalline in SiO₂ matrix prepared by using an ion implantation and subsequent heat treatment can not be described by a formula for the isolated Fe nanocrystalline. The large stresses or chemical bond force to which interface atoms may be subjected lead to increase effective anisotropic constant. In addition a little concentration of oxygen atoms contained in the crystalline might enhance the hyperfine field.

The selective dielectric heating of microwave energy to convert a portion of each pyrite particle to moderately magnetic pyrrhotite has been suggested to enhance the magnetic separation of inorganic sulfur from coal. The results for Mossbauer analyses show that the considerable amount of pyrrhotite produced during microwave irradiation, carrying with it some of non-magnetic pyrite (unconverted), ferrous sulfate, and troilite, is completely removed from coal after magnetic separation. The optimum desulfurization efficiency can be attained by appropriately controlling the irradiation time to maximize the amount of pyrrhotite formed pyrite decomposition. Excessive irradiation would be disadvantageous for improving magnetic separation due to the further decomposition of pyrrhotite to antiferromagnetic troilite.

Residues of ¹⁴C-fenitrothion in a model rice-fish ecosystem and field rice-fish ecosystem were studied. When equal amounts of the pesticide were applied, the extractable residues in brown rice (equivalent to 34.3 ± 1.9µg/kg fenitrothion) and rice stems and leaves (20.9 ± 1.5µg/kg) of the model rice-fish ecosystem were 10—15 times higher than that of the field rice-fish ecosystem (4.48 ± 0.13µg/kg and 1.27 ± 0.34µg/kg respectively). Residues in upper part of the soil (6.50 ± 0.1—8.10 ± 0.2µg/kg) and lower part of the soil (1.30 ± 0.1—1.50 ± 0.1µg/kg) of the model rice-fish ecosystem were 10—40 times higher than that of the field rice-fish ecosystem (0.17 ± 0.01µg / kg). The extractable residues in paddy water of the model ecosystem (0.30 ± 0.01µg/kg) were similar to that of the field ecosystem (0.20 ± 0.02µg / kg). When the fenitrothion was sprayed on the rice plants, residues in brown rice, fish body, soil and paddy water were lower than those when the pesticide was sprayed on the surface of the soil.

The behaviors of Si ions implanted into (100) GaAs at liquid nitrogen temperature with energy of 48 keV at the doses of 1×10¹⁵—5×10¹⁵ ions / cm² has been investigated in this study. The Rutherford backscattering-channeling (RBS-C) combined with particle induced X-ray emission (PIXE) has been used to determine the sites of the Si atoms in the GaAs substrate. The four-point probe was used to measure the resistance of the GaAs before and after Si ions implantation. The experimental results show that Si atoms occupy not only on Ga site but also on As site. The sheet resistivity of GaAs reduced from 1×10⁹Ω/□ to 4.5×10⁶Ω /□ after Si ions implanted, and to 4.0 × 10⁴Ω/□ after annealing at 850°C in argon. These results are consistent with some other investigations, for instance, the results of G.Braunstein et al and R. S. Bhattacharya et al, although the implantation condition is not the same.

Either sublinear or supralinear responses of dosimeters to γ-ray can be described by a response function derived from statistical Poisson distribution. The characteristic parameters of the function determine linearity, sublinearity and supralinearity in their responses. The experimental data of gamma dose-responses of alanine ESR dosimeters, film dosimeters, LiF(Mg, Cu, P) and LiF(Mg, Ti) thermoluminescence dosimeters are used to test the response function.