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• Author or Editor: G. Sun
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## On a generalization of Hua’s theorem with five squares of primes

Acta Mathematica Hungarica
Authors:
G. Lü
and
H. Sun

## Abstract

We sharpen Hua’s theorem with five squares of primes by proving that every sufficiently large integer N congruent to 5 modulo 24 can be written in the form
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{bbm} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$N = p_1^2 + p_2^2 + p_3^2 + p_4^2 + p_5^2$$ \end{document}
with p 1
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{bbm} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$N^{\tfrac{{49}} {{288}}}$$ \end{document}
.
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## Extraction of uranium(VI) from nitric acid solution by N,N-dibutyldodecanamide

Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. Sun
,
Y. Wang
,
S. Sun
, and
B. Bao

## Abstract

The partition of uranium(VI) between nitric acid solutions and solutions of N,N-dibutyldodecanamide (DBDA) in kerosene has been investigated at varying concentrations of nitric acid, extractant, salting-out agent LiNO3 and at different temperatures. The mechanism of extraction is discussed in the light of the results obtained.

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## Extraction of U(VI) and Th(IV) from nitric acid solutions with N,N,N′,N′-tetrahexylsuccinylamide

Journal of Radioanalytical and Nuclear Chemistry
Authors:
Y. Wang
,
G. Sun
,
B. Bao
, and
S. Sun

## Abstract

A new diamide N,N,N,N-tetrahexylsuccinylamide (THSA) was synthesized, characterised and used for the extraction of U(V) and Th(IV) from nitric acid solutions in a diluent composed of 50% 1,2,4-trimethylbenzene (TMB) and 50% kerosene (OK). Extraction distribution coefficients of U(VI) and Th(IV) as a function of aqueous nitric acid concentration, extractant concentration and temperature have been studied. The composition of extracted species, equilibrium constants and enthalpies of extraction reactions have also been calculated. The IR spectra of saturated extraction of U(VI) and Th(IV) were recorded.

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## Doppler-broadened boron peak analysis by using a modified spectral decomposition algorithm

Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. Sun
,
C. Park
, and
H. Choi

## Abstract

Doppler broadening of a 477.6 keV line combined with a recoil of an excited Li nucleus is the characteristic of PGAA, which leads to complicated gamma-ray spectrum which is difficult to analyze. For this solution, a modified algorithm for an automated analysis of the Doppler-broadened peak spectrum is presented. The modified algorithm maintained the consistency of a Doppler-broadened peak with the finest analysis algorithm used for a Gaussian gamma-ray peak analysis in the HYPERMET code.

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## N,N,N′,N′-tetrabutylmalonamide as a new extractant for extraction of nitric acid and uranium(VI) in toluene

Journal of Radioanalytical and Nuclear Chemistry
Authors:
Y. Wang
,
G. Sun
, and
B. Bao

## Abstract

N,N,N,N-tetrabutylmalonamide (TBMA) was synthesized and used for extraction of uranyl(II) ion from nitric acid media in toluene. The effects of nitric acid concentration, extractant concentration, temperature and salting-out agent (LiNO3) on distribution coefficients of uranyl(II) ion have been studied. The extraction of nitric acid is also studied. The main adduct of TBMA and HNO3 is HNO3. TBMA in 1.0 mol/l nitric acid solution. The 1:2:3 complex of uranyl(II) ion, nitrate ion and TBMA as extracted species is further confirmed by IR spectra of the extraction of uranyl(II) ion with TBMA, and found that the NO 3 in the extraction species UO2(NO3)2·3TBMA did not participate in coordination of uranyl(II) ion. The values of thermodynamic parameters have also been calculated.

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## Prompt k 0-factors and relative gamma-emission intensities for the strong non-1/ v absorbers 113Cd, 149Sm, 151Eu and 155,157Gd

Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. Sun
,
S. Byun
, and
H. Choi

## Abstract

Prompt k 0-factors relative to chlorine and relative g-emission intensities were determined for the strong non-1/v absorbers 113Cd, 149Sm, 151Eu,155Gd and 157Gd. Measurements were performed using the SNU-KAERI prompt gamma activation analysis (PGAA) facility at the Korea Atomic Energy Research Institute (KAERI). For proper experimental determination of the prompt k 0-factors, the effective g-factor and cadmium ratio were taken into account, in consideration of the effects from the non-1/v capture cross section and neutron spectrum in the thermal and epithermal energy region. By using the actual spectrum of the neutron beam in this study, the effective g-factor was obtained by calculation, and the influence of epithermal neutrons on the capture rate was corrected by measuring the cadmium ratio for each non-1/v target isotope. The measured prompt k 0-factors were used to check the consistency between the existing dataset of the absolute g-emission intensity and the 2200 m/s capture cross section for these isotopes.

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## Extraction of uranyl(VI) ion with N,N-diethyloctadecanamide from nitric acid solution

Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. Sun
,
B. Bao
, and
Ch Liu

## Abstract

The extraction of U(VI) with newly synthesized alkylamide, N,N-diethyloctadecanamide (DEODA), has been studied. The dependence of the extraction on nitric acid concentration, DEODA concentration and temperature from nitric acid solution has been considered. The extracted species has also been investigated using FT-IR spectrometry. The related themodynamic functions were calculated.

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## Extraction of uranyl(VI) ion with N,N-dibutyldodecanamide in toluene

Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. Sun
,
Y. Wang
, and
B. Bao

## Abstract

The extraction of U(VI) with newly synthesized long chain alkyl amide, N,N-dibutyldodecanamide (DBDA), in toluene has been studied. The dependence of the extraction on nitric acid and DBDA concentrations and temperature from nitric acid solution has been considered. The extracted species has also been investigated using FT-IR spectrometry. The related thermodynamic functions were calculated. The separation factor between U(VI) and Th(IV) is higher and there is no third phase formation under the conditions studied.

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## Stability of Gabor frames with arbitrary sampling points

Acta Mathematica Hungarica
Authors:
Hans G. Feichtinger
and
Wenchang Sun

## Summary

We study the stability of Gabor frames with arbitrary sampling points in the time-frequency plane, in several aspects. We prove that a Gabor frame generated by a window function in the Segal algebra S 0(R d) remains a frame even if (possibly) all the sampling points undergo an arbitrary perturbation, as long as this is uniformly small. We give explicit stability bounds when the window function is nice enough, showing that the allowed perturbation depends only on the lower frame bound of the original family and some qualitative parameters of the window under consideration. For the perturbation of window functions we show that a Gabor frame generated by any window function with arbitrary sampling points remains a frame when the window function has a small perturbation in S 0(R d) sense. We also study the stability of dual frames, which is useful in practice but has not found much attention in the literature. We give some general results on this topic and explain consequences to Gabor frames.

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## Thermal hazard evaluation of complex reactive substance using calorimeters and Dewar Vessel

Journal of Thermal Analysis and Calorimetry
Authors:
J. Sun
,
X. Li
,
K. Hasegawa
, and
G. Liao

## Abstract

In this paper, several small-scale screening test methods were discussed on evaluating the thermal hazard of reactive substances. Generally the sensitivities of DSC and ARC are not high enough to evaluate the thermal hazards for all reactive substance, especially, for those of complex reactions containing a phase and/or chemical reaction mechanism change in the lower temperature range. Using the C80, however, the reaction can easily be detected in the lower temperature range due to its high sensitivity. Therefore, the C80 gives generally more accurate results than DSC and ARC. Data from C80 and Dewar vessel were compared and it indicates that the Dewar vessel has also high enough sensitivity to evaluate the thermal hazard and determine the heat flux in lower temperature range of reactive substances.

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