[en] A 4πβ-4πγ detector configuration with a 4πβ(PC) flow proportional counter and a large size well-type 4πγ NaI(Tl) crystal was described, and the theoretic function of sum efficiency extrapolation was established. The radioactivities of ⁶⁰Co and ¹³⁴Cs source were measured using this sum extrapolation method, 0.29% and 0.19% relative uncertainty obtained for each, and the result was compared with the value of coincidence efficiency extrapolation. The analysis indicates this method is fit for measuring the activity of complex decay nuclides. (authors)

[en] Gamma-ray relative intensities determined with a HPGe spectrometer must be corrected for cascade coincidence when a soruce with cascade transition is placed close to the detector surface. Generally, normal correction method is approximate calculation from simplified decay scheme, thus the method is suitable for simple decay scheme or case of small cascade correction. The present research promoted a complicated correction method, and a computer program was developed to calculate the cascade correction in a complex spectrum. In order to test the reliability of program, a standard source of ¹⁵²Eu was measured and the test results show that this method can be applied to the cascade correction for complex decay scheme. (authors)

[en] ⁸⁹Rb is an important fission product used for monitoring possible release of fission products from fuel element. The half-life is one of important nuclear parameters. The half-life of ⁸⁹Rb was determined using reference source method with two sets of HPGe detectors by place-relay way. In reference source method, the ratio of net full- energy peak areas from the measure nuclide and the reference source was used to avoid the count correction caused by dead time and pileup. For the very short half-life of ⁸⁹Rb, the half-life iterative method was used in data analysis and the translation method was used in data unification. Finally, the measured half-life of ⁸⁹Rb is (14.41±0.04) min. (authors)

[en] ¹⁵²Eu is an important radionuclide for the energy and efficiency calibration of the HPGe gamma-detector. The preparation procedure is as following: purification and identify for purity of ¹⁵² Eu, homogeneity test, stability test, and measurement. According to the statistical tools, the spot-check samples from the solution in ampoule are measured for homogeneity test by πβ(PPC)-γ. The minimum sample for spot-check foe measurement by πβ(PPC)-γ is about 10-40 mg solution. The solution in ampoule have been stored for one year, then the spot-check samples are measured for stability test by πβ(PPC)-γ, the results prove that the solutions are stable. The certified value was measured by different laboratories using different ways. The last result of ¹⁵²Eu is 499.1(1 ± 0.5%) kBq/g(α = 0.05). (authors)

[en] Several key issues of a LaBr₃(Ce) γ spectrometer system for the measurement of fission products were studied to satisfy the real-time monitoring requirement of primary coolant. The selection of radionuclides in the fission products, high energy efficiency calibration, coincidence summing correction, pulse pile-up and the stabilization of spectrometer were the key concerns. Some preliminary solutions were obtained by the method of experimental tests combined with Monte Carlo calculation. The ongoing solving key problems are important for improving the reliability with the IaBr₃(Ce) γ spectrometer in the radionuclides analysis of primary coolant, the damage monitoring of fuel element and radionuclides monitoring in nuclear accident,et al. (authors)

[en] Despite the high theoretical specific capacity and energy density, the practical application of lithium‐sulfur (Li−S) battery is still hampered by the shuttle of lithium polysulfides and sluggish kinetics of cathode, which results in the loss of active materials and rapid capacity decay of the sulfur cathode. Herein, we develop novel hierarchical ultrathin porous carbon shell anchored with RuO${}_2$ nanoparticles as efficient cathode hosts for lithium‐sulfur batteries. The carbon shell can allow efficient impregnation of sulfur and provide effective spatial confinement to reduce polysulfide diffusion. In addition, the volume expansion of sulfur upon lithiation can be also remitted due to the sufficient space inside the carbon shell. The anchored RuO${}_2$ nanoparticles in the host material can synergistically enhance the immobilization of polysulfide and accelerate their redox reaction. Accordingly, this hierarchical structure based‐cathode containing 70.6 wt% sulfur content delivers enhanced electrochemical performances including high specific capacity, excellent rate performance and superior cycling stability. (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

[en] The paper describes the sensitivity curve measurements and applications for radioactivity meter. The energy-dependent sensitivity curve is established with the activity of standard sources and their corresponding current by constructing functions sub-section. Thus the current-activity ratio is acquired from the sensitivity curve and the calibration of radioactivity meter is solved satisfactorily. (authors)

[en] The radioactivity and the absolute gamma emission probability for the 641 keV main gamma ray of the short half nuclide ¹⁴²La were measured by DCC on a 4πβ-4πγ and a 4πγ-4πγ coincidence counting devices,and the standard uncertainty for the radioactivity measurement result is 0.46%, the emission probability of the 641 keV gamma ray is 0.473±0.005, which is only 0.24% lower than the data 0.474±0.005 proposed by the Table of Isotopes, 8th edition. The relative emission probabilities of the other main gamma rays were measured by another HPGe gamma spectrometer, which relative efficiency is above 60%, the measurement results are good. The half life of ¹⁴²La was calculated to be (91.0±0.7)min, which has a lower deviation of 0.2% than (91.1±0.5)min proposed by the Table of Isotopes, 8th edition. (authors)

[en] To study the clinical significance of serum collagen type IV in patients with severe acute respiratory syndrome (SARS), the level of serum collagen type IV in 66 patients with SARS was measured by RIA and compared with control group. The results showed that level of serum collagen type IV in patients with SARS was significantly higher than that in control group. The positive rate of level of collagen type IV in convalescent patients was 28.7%. Higher level of serum collagen type IV was found in patients whose chest X-ray examination showed that the focus was absorbed slowly. There was higher level of serum collagen type IV in some patients with SARS and this was related to focus absorption and extent of fibrosis. The level of serum collagen type IV may be a better indicator of monitoring extent of pneumonofibrosis

[en] To study the clinical significance of serum SOD in patients with severe acute respiratory syndrome (SARS), the level of serum SOD in 66 patients with SARS was measured by RIA and compared with control group. The results showed that the level of serum SOD in patients with SARS was significantly lower than that in control group. The serum SOD level in severe type of patients was lower than that in general type. The serum SOD level in convalescent patients was increased, but still lower than that in control group. There were excessively free radicals in patients with SARS, so SOD was depleted excessively. The change of SOD in patients with SARS maybe reflect the severe degree of ill. Dynamic detection of serum SOD level was helpful in analyzing serious or mild SARS. It may be an important therapeutic measure that excessively free radicals were eliminated from the body