High-resolution neutronics model for ^(238)Pu production in high-flux reactors

We proposed and compared three methods(filter burnup,single energy burnup,and burnup extremum analysis)to build a high-resolution neutronics model for 238Pu production in high-flux reactors.The filter burnup and single energy burnup methods have no theoretical approximation and can achieve a spectrum resolution of up to~1 eV,thereby constructing the importance curve and yield curve of the full energy range.The burnup extreme analysis method combines the importance and yield curves to consider the influence of irradiation time on production efficiency,thereby constructing extreme curves.The three curves,which quantify the transmutation rate of the nuclei in each energy region,are of physical significance because they have similar distributions.A high-resolution neutronics model for ^(238)Pu production was established based on these three curves,and its universality and feasibility were proven.The neutronics model can guide the neutron spectrum optimization and improve the yield of ^(238)Pu by up to 18.81%.The neutronics model revealed the law of nuclei transmutation in all energy regions with high spectrum resolution,thus providing theoretical support for high-flux reactor design and irradiation production of ^(238)Pu.

Signal-purity-spectrum-based colored deconvolution

Signal to noise ratio （SNR） and resolution are two important but contradictory characteristics used to evaluate the quality of seismic data. For relatively preserving SNR while enhancing resolution, the signal purity spectrum is introduced, estimated, and used to define the desired output amplitude spectrum after deconvolution. Since a real reflectivity series is blue rather than white, the effects of white reflectivity hypothesis on wavelets are experimentally analyzed and color compensation is applied after spectrum whitening. Experiments on real seismic data indicate that the cascade of the two processing stages can improve the ability of seismic data to delineate the geological details.

Study on Spectra of La_2CaB_(10)O_(19)∶Eu^(3+) in VUV-VIS Range

Excitation and emission spectra of new borate La_2CaB_(10)O_(19) doped Eu^(3+) in VUV-VIS range, high resolution (emission) spectra at room temperature and lifetime of Eu^(3+) were investigated. The emission line at about 616 nm attributed to the (()~5D_0)-(()~7F_2) transition of Eu^(3+) is the most intense emission of Eu^(3+). The broad band at about 244 nm is originated from charge transition band (CTB) of O^(2-)→Eu^(3+). According to the numbers of spectral lines (()~5D_0)-(()~7F_0) and (()~5D_0)-(()~7F_1) in high-resolution spectrum, Eu^(3+) ions occupy two crystallographic sites. The lifetimes of (()~5D_0)-(()~7F_0) transition of Eu^(3+) of two kinds of lattice sites are individually 2.1 and 2.6 ms, and both are exponential decay. In the VUV excitation spectrum, complicated band between 130 and 170 nm consists of host absorption and f-d transition of Eu^(3+).

Preparation and Certification of a New Salvianolic Acid A Reference Material for Food and Drug Research

Salvianolic acid A(Sal A),a water-soluble ingredient in Danshen,has various biological activities.Sal A and its impurities have similar physical and chemical properties,as well as strong reducibility;therefore,they are difficult to prepare and purify.In this study,high-purity Sal A was obtained by purification of sephadex chromatography and preparative chromatography.Furthermore,HPLC-DAD tandem ECD and HPLC-DAD tandem MS methods were used for non-volatile organic impurity analysis,ICP-MS method was used for non-volatile inorganic impurities and mass balance method and quantitative nuclear magnetic resonance were employed to certify the product.The structures of Sal A and its relative impurities were validated by nuclear magnetic resonance spectroscopy and mass spectrometry,and their contents were quantified as well.Following the principles of ISO Guides 34:2009 and 35:2005,a Sal A reference material was certified,covering homogeneity studies,stability studies,characterization,and uncertainty estimations.

Reinvestigate the C^2Π-X^2Π(0,0)Band of AgO

The C^2Π-X^2Π(0,0)band of AgO has been reinvestigated by laser induced fluorescence spectroscopy with a spectral resolution of ~0.02 cm^−1.The AgO molecules are produced by discharging a gas mixture of O2/Ar with silver needle electrodes in a supersonic jet expansion.By employing a home-made narrowband single longitude mode optical parametric oscillator(SLM-OPO)as the laser source,high-resolution spectra of the C^2Π-X^2Π(0,0)band have been recorded for both 107Ag16O and 109Ag16O isotopologues.The spectroscopic constants of the C^2Π state are consequently determined,with the 109Ag16O one being reported for the first time.The nature of the spin-orbit coupling effect in the C^2Π state is proposed to be due to state mixing with the nearby repulsive 4Σ− and 4Π states.