Vol.13,

215

The collision-induced reaction of Na⁺ ion with neutral C₆₀ vapour was investigated at the energy range of 10 to 150 eV. The deposited films were studied via laser desorption time-of-flight mass spectroscopy (TOFMS). The fragment products of C₆₀ with even number of carbon atoms, such asCn+ (n=58, 56, 54), and adduct products, such asCn+(n=62, 64, 66, 68) were observed in the positively charged TOF mass spectra. The endohedral fullerene ion of Na@C60+ was detected when collision energies are above 20 eV. Besides, no negative endohedral fullerene was detected. the products appearing in positively charged mass spectra were also observed in the negatively charged mass spectra. In addition, a series of products with odd number of carbon atoms, such asCn- (n=53, 55, 57, 59, 61, 63, 65, 67), also appeared, but the intensities of their signals were not as high as that of even numbered. Finally, it is interesting to find that the deposited films are insoluable in toluene, benzene or water. Their Fourier transform infrared (FTIR) spectra seem like those photopolymerized ones. Some of the reaction schemes are proposed to explain the experimental results.

363

In this paper, a magnetooptic chip was prepared on Si wafer by combinatorial Ga⁺ implantation into ion sputtered Co₇Ag₉₃ film. The surface morphology of each unit of the chip was detected by AFM, while their Kerr effect was measmed by MOKE equipment. It is observed that the maximum Kerr rotation (MKR) occurs when the incident photon energy is around 3.8-3.9 eV. Summarization of MKR versus implanted Ga⁺ dose shows that the MKR enhancement by Ga+ implantation can be characterized as incubation, enhancement and saturation regions. Considering the mutual solubility and surface morphology transition after annealing, it is suggested that Ga⁺ tends to form CoGa and/or CoGa₃ intermetallic compounds. Before the formation of CoGa₃ compounds, no apparent MKR enhancement could be observed. While when the surface is half occupied by forest-like CoGa₃ compounds. MKR enhancement will be saturated. By comparison of the maximum Kerr rotation with the cone areal density, it can be induced that not only the bulk concentration and structure, but also the surface morphology plays an important role in magnetooptic Kerr effect.

218

312

207

CVD diamond microdosimeter is an ideal substitute of common Si. GaAs detector for extremely strong radiation experimental environment due to its high band gap energy, fast charge collection, low dielectric constant and hardness. In order to improve its character, a CVD diamond microdosimeter was irradiated by a proton dose of 46 Gy, and a lateral micro-ion beam induced charge (IBIC) technique was utilized to characterize it in low beam current (~fA). It was clearly shown that charge collection efficiency and energy resolution were greatly improved after proton irradiation of that dose. Moreover, the homogeneities of both its counting performance and collection efficiency were enhanced. Proton irradiation of 46 Gy has been proved to be an effective way to prime a CVD diamond.

196

Investigations on surface decomposition of GaN implanted with low energy (80 keV) Eu ion to a low dose (1×10¹⁴ cm^-2), and its annealing behavior under high temperature (1050°C) in N2 are performed. The as-grown, as-implanted and annealed GaN films are characterized by proton elastic scattering (PES), Rutherford backscattering spectrometry (RBS), photoluminescence (PL) and atomic force microscopy (AFM). The results show that Eu ion implantation induces radiation defects and decomposition of GaN. The GaN surface decomposition is more serious during high temperature annealing. The atomic ratio of N in as-grown, as-implanted and annealed GaN film is 47 at.%, 44 at.% and 40 at.%, respectively. As a result, a rough Ga-rich layer is formed at the surface, though the lattice defects are partly removed after high temperature annealing.

471

210

Using dipyridamole stress test to evaluate cerebral blood flow reserve in cerebrovascular disease (CVD). Dipyridamole stress tests were performed first, the baseline SPECT images were obtained under similar conditions 2-5 days later. By visual and semiquantitative analysis, the responses of cerebral blood flow to dipyridamole were divided into the following four patterns: A: The dipyridamole SPECT showed an expanded area of hypoperfusion, Asymmetry Index(AI) and Uptake Rate(UR) were all decreased; B: Rest images was normal but new hypoperfused areas appeared on stress test with decreased Al and UR; C: Hypoperfused areas were decreased in size or disappeared after stress test with increased AI and UR; D: No changes showed in cerebral perfusion imaging patterns, and in AI and UR between stress and rest studies. Dipyridamole brain perfusion imaging may be helpful to the diagnosis of CVD, to the decision the therapeutic plan, and to predicting the therapeutic effect.

219

In order to evaluate correlation of glucose metabolism and DNA ploidity of tumors, the uptake of ¹⁸F-Deoxyglucose (FDG) by PET prior to surgery and the DNA cotent and DNA-grading of malignancy (DNA-MG) of Schiff-stained nuclei obtained from fresh tumor fragments by means of image cytometry were studied, and thereafter the correlation between standardized uptake value (SUV) and (DNA-MG) was analysed in forty-nine patients with histologically proven non-small cell lung carcinoma (NSCLC). As a result of the DNA histograms of these 49 patients, 46 (93.88%) were aneuploid and only 3(6.12%) were tetraploid. A linear correlation of the SUV versus the (DNA-MG) (r=0.336, p=0.024) was found, demonstrating that ¹⁸F-FDG PET as a non-invasive metabolic imaging technique, may also provide information correlated to malignant DNA patterns which may be valuable in malignant differentiation and prognostic prediction.

201