Vol.22,

RF circuit board has a significant impact on performance of the Digital Beam Position Monitor (DBPM) in storage ring of a synchrotron radiation facility. In this paper, a front-end RF board is designed for DBPM, and schematics of the RF board and the test results are given. In view of the inevitable inconsistency in the multi-channel circuit, a calibration circuit is designed to reduce such an influence. The test results show that the calibration method is useful for beam current dependence which is sensitive to channels inconsistency.

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Many mutants of plant induced by heavy ion beam irradiation have been reported in recent years, but leaf anthocyan mutants induced by ion irradiation in evergreen were rarely found. In this study, a color-leaf mutant with purple leaves, stems and petals was isolated from clones of Wandering Jew irradiated by 95.8 MeV/u carbon ion beam. The concentration and histological distribution of leaf pigment were surveyed in wild type and mutant. In mutant, contents of total chlorophylls (Chl), chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids (Car) decreased significantly, while concentration of the anthocyanins was 6.2-fold higher than that of wild type. Further composition analysis of anthocyanins by electrospray ionization mass spectrometry (ESI-MS) indicated that the purple pigmentation of leaves in mutant was caused by accumulation of petunidin anthocyanin. Microscopic examination showed that most petunidin anthocyanin accumulated in the lower epidermis, and little in vascular parenchyma of mutant, while there was no pigment in wild type. Meanwhile, in spongy parenchyma of mutant we observed little Chl, which the wild type abounds in. In conclusion, the color-leaf mutant of Wandering Jew induced by irradiation of carbon ions was improved in ornamental value, and it could be contribute to variation in level, component and distribution of foliar pigment. The possible mutation mechanisms were discussed.

380

A film dosimeter based on optically stimulated luminescence (OSL) material of CaS:Ce,Sm was developed for online irradiation dosimetry measurement. The stimulation is provided by a laser with a wavelength of 980 nm, and the OSL luminescenceis collected by a photodiode. Using ⁶⁰Co γ-rays, we investigated the dosimetry characteristic of the dosimeter at different dose rates and total doses. The real-time detection results showed that the OSL signals versus total ionizing dose exhibited a good linearity in a dose range of 0.1-185 Gy.

361

For scanning transmission proton microscopy tomography, to compare cell images of the proton stopping power and relative electron density, two cell phantoms are designed and simulated by code FLUKA. The cell images are reconstructed by the filtered back projection algorithm, and compared with their tomography imaging. The images of stopping power and relative electron density slightly vary with proton energies, but the internal images are of clear with high resolution. The organic glass image of relative electron density reveals the resolution power of proton tomography. Also, the simulation results reflect effects of the boundary enhancement, the weak artifacts, and the internal structure border extension by multiple scattering. So using proton tomography to analyze internal structure of a cell is a superior.

297

N, N-diethylhydroxylamine (DEHA) is a novel salt-free reducing agent used in separating Pu and Np from U in the reprocessing of spent nuclear fuel. In this paper, we report the study on γ-radiolysis of DEHA in water and its radiolytic liquid organics by gas chromatography. The radiolysis rate of DEHA increases with the absorbed dose, but decreases with the primary DEHA concentration at 0.1–0.5 mol·L^–1 irradiated to 10–1000 kGy. The main organics produced in radiolysis of DEHA are acetaldehyde, acetic acid and ethanol. The concentration of acetaldehyde increases with the primary DEHA concentration and the absorbed dose at ≤500 kGy, but over 500 kGy it decreases with increasing dose. The dependence of the concentration of acetic acid on the absorbed dose is similar to that of acetaldehyde, with a lower turning point of the dose, though. The ethanol concentration changes differently among the irradiated samples of different primary DEHA concentrations, and this is discussed. The maximum concentrations of acetaldehyde, acetic acid and ethanol are 0.029, 0.014 and 0.028 mol·L^–1, respectively.

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Nanographene oxide (NGO) is currently being explored for various biomedical applications. However, little information is known about its biological behaviors in vitro and in vivo. For further studying its pharmacokinetics and related biological behaviors in living systems, an effective and convenient tracing method is particularly demanded. In this work, NGO was labeled with radionuclide ¹⁸⁸Re (¹⁸⁸Re-NGO). To obtain high labeling yield and purity, a number of labeling conditions, including concentration of SnCl₂ and ascorbic acid, reaction time and temperature, and pH were optimized, and stability of the ¹⁸⁸Re-NGO in vitro and in vivo was evaluated. The results showed that NGO could be effectively labeled with high yield. The purified ¹⁸⁸Re-NGO showed high stability in vitro and in vivo. A pretest of NGO biodistribution with single photon emission computed tomography showed that the ¹⁸⁸Re-NGO was rapidly taken by organs such as lungs, liver, and spleen. The biodistribution of ¹⁸⁸Re-NGO differs significantly from the free radionuclide, indicating that the labeling procedure is highly suitable for investigating its biological behavior in living systems.

364

A novel histidine derivative containing 4-nitroimidazole, (S)-2-(4-((4-nitro-1H-imidazol-1-yl) methyl) benzamido) -3- (1H- imidazol-4-yl)propanoic acid (His-NI), was synthesized and labeled with [^99mTc(CO)₃(H₂O)₃]⁺. The tricarbonyl technetium complex, the ^99mTc(CO)₃-His-NI, showed a 99% yield under mild conditions at a low His-NI ligand concentration of 10^–4 mol∙L^–1, and its biodistribution in mice bearing S180 tumor had a selective accumulation in tumor (2.01±0.40 %ID/g at 1 h postinjection) and a slow clearance. The tumor/muscle ratio was 1.64 at 1 h, 3.10 at 4 h, and 3.88 at 24 h, indicating that the ^99mTc(CO)₃-His-NI has a potential to image tumor hypoxia.

285

In this study, the influence of respiratory motion on Cone Beam CT (CBCT) image quality was investigated by a motion simulating platform, an image quality phantom, and a kV X-ray CBCT. A total of 21 motion states in the superior-inferior direction and the anterior-posterior direction, separately or together, was simulated by considering different respiration amplitudes, periods and hysteresis. The influence of motion on CBCT image quality was evaluated with the quality indexes of low contrast visibility, geometric accuracy, spatial resolution and uniformity of CT values. The results showed that the quality indexes were affected by the motion more prominently in AP direction than in SI direction, and the image quality was affected by the respiration amplitude more prominently than the respiration period and the hysteresis. The CBCT image quality and its characteristics influenced by the respiration motion, and may be exploited in finding solutions.

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The passive residual heat removal exchanger (PRHR HX), which is a key equipment of the passive residual heat removal system, is installed in an elevated pool. Its heat transfer performance affects security and economics of the reactor, and boiling heat transfer in the liquid surrounding the exchanger occurs when the liquid saturation temperature exceeded. The smooth tubes, which are widely used as heat transfer tubes in PRHR HX, can be replaced by some enhanced tubes to improve the boiling heat transfer capability. In this paper, the pool boiling heat transfer characteristics of smooth tube and a machined porous surface tube are investigated by using high-pressure steam condensing inside tube as heating source. Compared with smooth tube, the porous surface tube considerably enhances the boiling heat transfer, and shortens the time significantly before reaching the liquid saturation temperature. Its boiling heat transfer coefficient increases from 68% to 75%, and the wall superheat decreases by 1.5ºC. Combining effect of condensation inside tube with boiling outside tube, the axial wall temperatures of heat transfer tube are neither uniform nor linear distribution. Based on these investigations, enhance mechanism of the porous surface tube is analyzed.

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