Vol.21,

For X-ray powder diffraction spectra collected by an area detector of MarCCD on macromolecular crystallography beamline of SSRF, an energy calibration method was developed using LaB₆(660a) powder diffraction for in-situ rapid energy calibration of the X-rays without changing the experimental conditions. The intensity of each diffraction ring was integrated, and the accurate peak positions were fitted by Pseudo-Voigt function model. The sample's interplanar spacing for XRD analysis and the calibrated energy were obtained by the PCPDFWIN code and by fitting all the energies with the least-square method. The exposure time and the sample–to-detector distance were found no effect on accuracy of the energy calibration, and the in-situ energy calibration could be done with an accuracy of better than 0.4‰ in 7–18 keV. This method is applicable to other X-ray beamlines.

312

In this paper, A MySAS package, which is verified on Windows XP, can easily convert two-dimensional data in small angle neutron and X-ray scattering analysis, operate individually and execute one particular operation as numerical data reduction or analysis, and graphical visualization. This MySAS package can implement the input and output routines via scanning certain properties, thus recalling completely sets of repetition input and selecting the input files. On starting from the two-dimensional files, the MySAS package can correct the anisotropic or isotropic data for physical interpretation and select the relevant pixels. Over 50 model functions are fitted by the POWELL code using χ² as the figure of merit function.

398

The neutron response function and detection efficiency of a spherical proton recoil proportional counter (SP) play key roles in precise measurement of neutron spectra of the interior materials. In this paper, the response functions and detection efficiency of three SPs developed at CAEP are simulated by Geant4. The simulated spectra are compared with pulse-height spectra measured at 0.165, 0.575, 1.4, and 14.1 MeV of incident neutrons. And the calculated detector efficiencies agree within 5% with the data obtained by neutron activation.

387

Thiamphenicol (THA) and florfenicol (FLO) aqueous solutions were irradiated to different doses by 1 MeV electron beams, and redox reactions of THA/FLO and radicals of ^·OH, e_aq⁻ and ^•H were investigated under various conditions. The results showed that at 8 kGy, the decomposition rate of THA and FLO was 97.2% and 98.5%, respectively. Quantitative and qualitative analysis indicated that ^·OH played a key role in E-beam degradation of the THA and FLO in aqueous solutions, and e_aq⁻ and ^•H radicals could initiate the degradation, too. Seven primary products of the THA and FLO degradation were identified. These indicate that E-beam radiation is an effective method to reduce THA and FLO in aqueous solutions.

340

Nuclides can move with groundwater either as solutes or colloids, where the latter mechanism generally results in much shorter traveling time as the nuclides interact strongly with solid phases, such as actinides. In the performance assessment, it is therefore essential to assess the relative importance of these two transport mechanisms for different nuclides. The relative importance of colloids depends on the nature and concentration of the colloids in groundwater. Plutonium (Pu), neptunium (Np), uranium (U) and americium (Am) are four nuclides of concern for the long-term emplacement of nuclear wastes at potential repository sites. These four actinides have a high potential for migrating if attached to iron oxide, clay or silica colloids in the groundwater. Strong sorption of the actinides by colloids in the groundwater may facilitate the transport of these nuclides along potential flow paths. The solubility-limited dissolution model can be used to assess the safety of the release of nuclear waste in geological disposal sites. Usually, it has been assumed that the solubility of the waste form is constant. If a nuclide reaches its solubility limit at an inner location near the waste form, it is unlikely that the same nuclide will reach its solubility limit at an outer location unless this nuclide has a parent nuclide. It is unlikely that the daughter nuclides will exceed their solubility limit due to decay of their parent nuclide. The present study investigates the effect of colloids on the transport of solubility-limited nuclides under the kinetic solubility-limited dissolution (KSLD) boundary condition in fractured media. The release rate of the nuclides is proportional to the difference between the saturation concentration and the inlet aqueous concentration of the nuclides. The presence of colloids decreases the aqueous concentration of nuclides and, thus, increases the release flux of nuclides from the waste form.

407

Glycyrrhizic acid (GA) in Glycyrrhiza uralensis (G. uralensis) is physiologically active. In this study, the total DNA of wild G. uralensis was randomly transformed into Hansenula anomala by implantation of low-energy Ar⁺ and N⁺, to produce five recombinant yeast strains relating to biological synthesis of the GA or Glycyrrhetinic acid (GAs). After culturing in liquid medium for 96 h, the resultant GA, 18α-GAs and 18β-Gas were determined by reversed-phase high performance liquid chromatography (RP-HPLC), and the corresponding concentrations were 114.49, 0.56, and 0.81 mg∙L^–1. After one hundred primers were analyzed with random amplified polymorphic DNA (RAPD), the seven different DNA fragments were produced by the N7059 strain of recombined yeasts, and, the polymerase chain reaction (PCR) verified that one of them came from the genome of G. uralensis, indicating a successful transfer of genetic information by ion implantation.

331

A low-dropout voltage regulator, LM2941, was irradiated by ⁶⁰Co γ-rays at various dose rates and biases for investigating the total dose and dose rate effects. The radiation responses show that the key electrical parameters, including its output and dropout voltage, and the maximum output current, are sensitive to total dose and dose rates, and are significantly degraded at low dose rate and zero bias. The integrated circuits damage change with the dose rates and biases, and the dose-rate effects are relative to its electric field.

438

To evaluate the ¹²⁵I radioactive probing re-canalizing stenostic nasolacrimal duct, the nasolacrimal duct stenosis models in epithelium and connective tissues are experimentally structured by inbred white rabbits (New Zealand), including the nasolacrimal duct stenosis, the mechanical probing with outer layer of thermoplastic tube, and the ¹²⁵I radioactive probing with the ¹²⁵I seeds sealing into the thermoplastic tube. After re-canalized for four weeks, tissue specimens from bilateral nasolacrimal ducts are obtained, and the Bcl-2 and Bax protein expression levels are evaluated by immunohistochemical staining analysis. Comparing with the blank control, the expression levels of the Bcl-2 and Bax in the nasolacrimal duct stenosis and the mechanical probing are significantly up-/down-regulated (p< 0.05), but in the ¹²⁵I radioactive probing are down-/up-regulated (p<0.05) and can be used to re-canalize the stenostic lacrimal passage. The results show that the ¹²⁵I radioactive probing is a therapeutical mechanism for radioactive probing strategy for treating nasolacrimal duct stenosis to induce cell apoptosis.

443

In this paper, we study the biological response induced by heavy ions irradiation of high dose, human peripheral blood lymphocytes are irradiated in vitro by the carbon ions of LET=35 keV/μm, and the chromosome aberrations at absorbed doses of 0–20 Gy are analyzed by the calyculin A-induced premature chromosome condensation (PCC). The frequencies of PCC-rings at the stage of G2/M-phase increase steeply with radiation doses up to 20 Gy at a rate of 0.017 Gy^–1. The G2-PCC index remains more than 5% up to 15 Gy, and 3% after 20 Gy, this is high enough to score a substantial number of chromosome spreads without dose-rate effect. The results show that the calyculin A-induced PCC technique is suitable for analyzing the chromosome damage induced by carbon ions irradiation of high dose.

382

In this paper, we report the electronics of a timing measurement system of PTB (portable TDC board), which is a handy tool based on USB interface, customized for high precision time measurements without any crates. The time digitization is based on the High Performance TDC Chip (HPTDC). The real-time compensation for HPTDC outputs and the USB master logic are implemented in an ALTERA's Cyclone FPGA. The architecture design and logic design are described in detail. Test of the system showed a time resolution of 13.3 ps.

396

Two tests of refilling and reflooding in the horizontal geometry channel under different pressure conditions, respectively, are conducted to understand the thermal hydraulics behavior during a LOCA in the CANDU reactor. One case of refilling a hot horizontal tube test and four cases of reflooding a horizontal fuel channel test series (35% and 60% break size of reactor inlet header with single-end injection or both-end injection, respectively) have been simulated. The horizontal channel is simulated with the model splitting as parallel pipes with cross flow junction component. The simulation results have been compared with the tests in terms of wall temperature or heated-pin surface temperature. The results are reasonably acceptable and it shows that the code is applicable on horizontal channel quenching.

281

The purpose of this study is to establish an intelligent expert system for nuclear power plant emergency response. A new framework of environmental risk management methodology by the concept of pattern recognition was introduced in this paper. A knowledge-based decision support system for emergency response and risk management of nuclear power plant was also discussed. The mathematical pattern relationship of accidental release effects on neighboring area and the corresponding response measures were presented in this paper. With this decision system, the decision maker can specify the procedure and minimize their human error in the decision process. The improvement of risk response and the quality of management system could be upgraded by this system. Besides, the methodology can also be served as a basis for the future development of environmental risk response system design.

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