Vol.16,

The parameters of beam transverse positions at HLS 200 MeV LINAC are very important to injection efficiency. We have designed a new non-interceptive strip line beam position monitor (BPM) as a substitution for the original interceptive fluorescent target. This paper gives out the theoretical analysis and bench test result of the strip line BPM. The BPM has a characteristic impedance of (50±5)Ω, a reflection coefficient of less than –4 dB, a bandwidth of 400 MHz, a coupling coefficient of less than -15 dB, and a sensitivity of 1.16 dB/mm. Additionally, the strip line BPM has a good linearity.

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In this work, top and back gate characteristics of partially-depleted NMOS transistors with enclosed gate fabricated on SIMOX which is hardened by silicon ions implantation were studied under X-ray total-dose irradiation of three bias conditions. It has been found experimentally that back gate threshold shift and leakage current were greatly reduced during irradiation for hardened transistors, comparing to control ones. It has been confirmed that the improvement of total-dose properties of SOI devices is attributed to the silicon nanocrystals (nanoclusters) in buried oxides introduced by ion implantation.

323

This work analyzed the gamma ray attenuation effect from the self-absorption and shield attenuation perspectively. An exact mathematical equation was given for the geometric factor of the cylindrical fissile material with dual shields. In addition, several approximation approaches suitable for real situation were discussed, especially in the radial and axial directions of the cylinders, since the G-factors have simple forms. Then the space distribution patterns of the G-factor were analyzed based on numerical result and effective ways to solve the geometric information of the cylindrical fissile material, the radii and the heights, were deduced. This method was checked and verified by numerical calculation. Because of the efficiency of the method, it is ideal for application in real situations, such as nuclear safeguards, which demands speed of detection and accuracy of geometric analysis.

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Superparamagnetic poly(acrylamide) magnetic nanogels produced via photochemical method have been developed. After Hoffmann degradation of carbonyl, the nanogels with amino groups, or poly(acrylamide-vinyl amine) magnetic nanogels, were also obtained. And the magnetic nanogels were further modified by methoxy poly(ethylene glycol) (MPEG) for higher dispersibility and stability. The MPEG-modified magnetic nanogels were characterized by X-ray diffraction (XRD), photo correlation spectroscopy (PCS) and scanning electron microscopy (SEM), respectively. The MPEG-modified magnetic nanogels were labeled by ¹⁸⁸Re radiopharmaceuticals and intravenously injected into tails of mice in the presence and absence of a 0.5 T external magnetic field targeted on the bellies. The radioactivity distribution was monitored in vivo. In the absence of magnetic field, the radioactivity was mainly distributed in liver, spleen, kidney, stomach and lung. In the presence of the magnetic field, the radioactivity was mainly accumulated on the targeted point, verifying the magnetically targeted character.

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O-(2-[¹⁸F]fluoroethyl)-L-tyrosine ([¹⁸F]FET), one of radiolabelled amino acids, is a very promising brain tumor positron emission tomography (PET) imaging agent and holds clinical potential. This paper described out a comparative and optimized radiosynthesis of [¹⁸F]FET, concerning three aspects of its two-step preparation method, including reaction components, heating methods and reaction models. As a result, good radiochemical yield (about 45%, no-decay-corrected) and radiochemical purity (more than 95%) were achieved, and total synthesis time of [¹⁸F]FET was shortened within 20 min and radiation exposure time also decreased.

369

The synthesis and biodistribution of β-amyloid plaques imaging agent [¹³¹I]-2- (4′-dimethylaminophenyl)-6-iodoimidazo[1,2-α] pyridine ([¹³¹I]IMPY) were reported. The chemical structure of the labeling precursor 2-(4′-dimethylaminophenyl)-6- (tributylstannyl) imidazo[1, 2-α] pyridine and all its intermediates were verified by IR,HNMR and MS. The radioiodinated compound was prepared using iododestannylation reaction by hydrogen peroxide. Final radiochemical purity was above 95% determined by TLC. The in vivo biodistribution of [¹³¹I]IMPY in normal mice showed excellent brain uptake and washout, indicating this thioflavin-T based small molecular probe has potential for in vivo imaging amyloid deposits.

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The aims of this study are to investigate the feasibility and validity of the L-[1-¹³C] phenylalanine breath test (¹³C-PheBT) which has been used to measure hepatocyte functional capacity in hepatitis B virus-related liver disease patients and to propose validity parameters of the test in 12 healthy volunteer, 8 chronic hepatitis and 26 liver cirrhotic patients. 100mg/body nonradiative L-[1-¹³C] phenylalanine (¹³C-Phe) was administered orally to all subjects. Breath samples were taken before and different intervals within 360 min after administration. The ¹³CO₂/¹²CO₂ enrichment was assessed by isotope ratio mass spectrometer. The parameter percentage ¹³C excretion rate ¹³CER_t (% ¹³C dose/h) all peaked within 10-30 min after oral ¹³C-Phe application. The parameters such as maximum value of ¹³C excretion rate, ¹³CER_max (% ¹³C dose/h) (controls: 18.0±3.3; Child A: 11.0±3.8; Child B: 5.0±0.5; Child C: 3.6±1.2), ¹³C excretion rate at 30min, ¹³CER₃₀ (% dose/h) (controls: 11. 9±2.1; Child A: 8.1±0.4; Child B: 6.1±0.9; Child C: 3.2±1.2), ¹³C cumulative excretion of first 60 min, ¹³Ccum₆₀ (% ¹³C dose) (controls: 9.3±1.4; Child A: 6.6±0.7; Child B: 4.1±0.3; Child C: 2.6±0.9) and half time of ¹³C excretion rate, T_1/2 (minutes) (controls: 40.4±4.4; chronic hepatitis: 53.4±4.4; Child A: 59.8±4.5; Child B: 102.0±17.3; Child C: 212.1±87.9) were effective indexes which could be employed to stage hepatocyte impairment and liver functional reserve of advanced HBV-related cirrhotic patients (i.e. healthy subjects, Child A, B, C); T_1/2 was also useful for distinguishing mild HBV-related liver injure.

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^99mTc-HYNIC-Annexin V was prepared for apoptosis radionuclide imaging in vivo. The expression plasmid of human Annexin V was constructed and expressed in E. coli.. HYNIC was prepared and used as bifunctional chelating agent for ^99mTc labeling. The radiochemical purity, radiolabeling yield and stability of ^99mTc-HYNIC-Annexin V were studied. The coding sequence of human Annexin V gene was successfully cloned into the expression vector, and highly expressed in E. coli. A protein with a molecular weight of about 36kD could be induced and confirmed by Western Blotting and SDS-PAGE. Annexin V could be labeled with ^99mTc using HYNIC, and showed high radiochemical purity of more than 90%. The radiolabeling yield could reach more than 90%. The reaction condition was moderate. It suggested that ^99mTc-HYNIC-Annexin V may be a promising agent for apoptosis imaging and clinical application.

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A data service system plays an indispensable role in HT-7 Tokamak experiment. Since the former system doesn't provide the function of timely data procession and analysis, and all client software are based on Windows, it can't fulfill virtual fusion laboratory for remote researchers. Therefore, a new system which is simplified by three kinds of data servers and one data analysis and visualization software tool has been developed. The data servers include a data acquisition server based on file system, an MDSplus server used as the central repository for analysis data, and a web server. Users who prefer the convenience of application that can be run in a Web Browser can easily access the experiment data without knowing X-Windows. In order to adjust instruments to control experiment the operators need to plot data duly as soon as they are gathered. To satisfy their requirement, an upgraded data analysis and visualization software GT-7 is developed. It not only makes 2D data visualization more efficient, but also it can be capable of processing, analyzing and displaying interactive 2D and 3D graph of raw, analyzed data by the format of ASCII, LZO and MDSplus.

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The paper is focused on the coupling effect between film boiling heat transfer and evaporation drag around a hot-particle in cold liquid. Based on the continuity, momentum and energy equations of the vapor film, a transient two-dimensional single particle model has been established. This paper contains a detailed description of HPMC (High-temperature Particle Moving in Coolant) model for studying some aspects of the premixing stage of fuel-coolant interactions (FCIs). The transient process of high-temperature particles moving in coolant can be simulated. Comparisons between the experiment results and the calculations using HPMC model demonstrate that HPMC model achieves a good agreement in predicting the time-varying characteristic of high-temperature spheres moving in coolant.

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