[en] Highlights: •A predator-prey model with delay was presented. •We showed effects of delay on patterns. •Pattern transition was obtained. •Rich patterns are shown in a predator-prey model. -- Abstract: Spatial diffusion and time delay are two main important factors in biological systems. In this paper, a predator-prey model with Holling III functional response, which includes time delay and diffusion processes is presented. It was found that time delay can induce transition from wave pattern to stationary pattern. Furthermore, for different values of time delay, different types of stationary patterns are obtained in the predator-prey model. These results may be useful for us to understand the pattern transition arising from intrinsic elements in the real ecosystems

[en] The positron–electron annihilation gamma-ray spectra of methanol have been studied in the present work. The contributions of the bound electrons to the Doppler-shift of gamma-ray spectra have been analysed as well. These bound electrons are divided into three groups: core, inner valence and outer valence rather than the conventional two groups: core and valence in the positron annihilation process in the present work. The results obtained show a dominance of the inner valence electrons of methanol rather than the electrons occupied in the highest occupied molecular orbital (HOMO) in the positron–electron annihilation process. These inner valence electrons occupied in 3a^′ and 4a^′ orbitals consist of over 80% outermost atomic 2s electrons in oxygen and carbon atoms. That the positron prefers to annihilate with these outermost s electrons in atoms is suggested.

[en] It was found in this study that 10 Gy radiation combined with Compound Tianxian Capsule (on the 3th day of tumor implantation; at a dosage of 2.5 k/kg P.O. once everyday for 3 days) promoted tumour regression significantly compared with 10 Gy radiation alone, with the therapeutic efficacy 1.89 times more than that of radiation alone. In the combined group, it was found that necrosis of the tumour cells was more severe, and there were many inflammatory cells surrounding the tumour. In addition, changes in the membranous structure and mitochondria appeared earlier and were more serious, indicating that membranous structure may be the target site of enhanced sensitivity of Compound Tianxian Capsule. Promotion of infiltration of inflammatory cells may be one of the expression forms of enhanced radiation sensitivity

[en] A new method, the radiosensitization method, was used to improve the radiotherapeutic effectiveness in 10 patients with various advanced, radioresistant and post-radiotherapeutically recurrent malignant tumors. These patients were randomly diveded into 2 groups: radiation + HPD (R + H) and simple radiation therapy (RT). The diagnosis in all these patients was confirmed pathologically and/or cytologically. The effective rate in R + H group was 100%, while that in RT group only 40%. The results showed that the difference of the short term effectiveness between these 2 groups was statistically significant (P < 0.05)

[en] We investigated the adsorption of HCOH molecule on the SiC sheet using density functional theory (DFT) calculations. It is found that the C atom of the SiC sheet is the active adsorption site and the HCOH molecule prefers to the C atom rather than the O and H atoms close to the SiC sheet. The calculated charge-transfer, electronic density difference image and the densities of states (DOS) show that the HCOH molecule could be firmly adsorbed by the SiC sheet and the electronic properties of the SiC sheet are affected by the adsorption of HCOH molecule. The SiC sheet would be promising candidate to detect the HCOH gas.

[en] Objective: To study the potential impacts of psychological intervention on anxiety relief of pediatric patients receiving radiotherapy. Methods: Ninety children with brain tumors who admitted to our hospital from 2016 to 2018 were randomly divided into intervention group and control group, 45 cases in each group. The indicators of the two groups were comparable. The control group was not given psychological intervention. Anesthesia were performed directly when the children in control group did not cooperate with radiotherapy. The intervention group was given psychological intervention on the basis of the control group. Anesthesia were performed after the psychological intervention was ineffective. SCL-90 score, SAS scale score, heart rate, diastolic pressure, systolic pressure, blood sugar, cortisol, and the rate of anesthetic use were observed before and after treatment. Results: The difference of hostility, anxiety, and fear before and after treatment in SCL-90 score of intervention group was significantly higher than that of control group (P < 0.05). After intervention, the SAS score of intervention group was 42.5 + 7.6, which was significantly lower than that of control group (51.4 + 9.2). The heart beats, diastolic blood pressure, systolic blood pressure, blood sugar and cortisol in the intervention group were significantly lower than those in the control group, at 2, 4 and 6 weeks afterwards (P < 0.05). In comparing to non-intervention group, the experimental group saw a clearly lower rate of anesthetic use (88.9% vs. 26.7%, P < 0.05). Conclusion: Psychological intervention is found to significantly improve the anxiety and fear of children with brain tumors during radiation treatments, indicating more widely clinical use in the near future. (authors)

[en] Lead-cooled Fast Reactor (LFR) has been chosen as one of the six Generation-IV reactor concept candidates due to its high performance in neutronics, thermal hydraulics and inherent safety features. Passive residual heat removal system (PRHRS) is a passive system that guarantees the residual heat removal of LFR even in the hypothetical beyond-design basis conditions. Based on a 1000 MW_th lead-bismuth cooled fast reactor, the design and performance analysis of PRHRS were conducted using RELAP5 code. First, a PRHRS removing heat by Independent Heat EXchanger (IHEX) was designed, which utilizes natural circulation, gravity field and has the characteristics of high reliability and inherent safety. Secondly, the lead-bismuth heat transfer model was developed and verified based on RELAP5/MOD 4.0 code, as the heat transfer model of Pressurized Water Reactor (PWR) is not suitable for the lead-bismuth heat transfer calculation. The RELAP5 model of LFR was established and verified by comparison with design parameters. The PRHRS performance was investigated under Loss of Power (LOP) transient to assess the feasibility of the PRHRS design. The results demonstrated that the heat removal rate of the PRHRS removing heat by IHEX exceeded the core decay rate at about 5 h. The cladding peak temperature of the PRHRS reached 562 °C, which was below the limit (750 °C). Therefore, the PRHRS removing heat by IHEX has the capability to remove the LFR residual heat and has the characteristics of high performance and inherent safety, which can be used as an independent residual heat removal system for commercial LFR. The work provides reference for the design and performance analysis of LFR PRHRS in the future.

[en] Aimed at problems of long term existed low mining efficiency and high cost in production of typical Gaoxi uranium deposit among southern hard rock with low grade of uranium deposit, also by support of the improvement and perfection of low grade uranium deposit hydrometallurgical technique through collection partition of irregular and disperse deposit, high efficient stage deep hole open stoping followed by back-filling method was discussed. Technical measure, technology characteristic, result and experience of the method application were basically summarized. And application prospect in southern Jiangxi low grade uranium deposit was probed. (authors)

[en] The analytic potential energy surface (APES) for the exchange reaction of HeH⁺ (X¹Σ⁺) + He at the lowest singlet state 1¹A^/ has been built. The APES is expressed as Aguado-Paniagua function based on the many-body expansion. Using the adaptive non-linear least-squares algorithm, the APES is fitted from 15 682 ab initio energy points calculated with the multireference configuration interaction calculation with a large d-aug-cc-pV5Z basis set. To testify the new APES, we calculate the integral cross sections for He + H⁺He (v= 0, 1, 2, j= 0) → HeH⁺+ He by means of quasi-classical trajectory and compare them with the previous result in literature.

[en] Accelerated degradation testing (ADT) is a common approach in reliability prediction, especially for products with high reliability. However, oftentimes the laboratory condition of ADT is different from the field condition; thus, to predict field failure, one need to calibrate the prediction made by using ADT data. In this paper a Bayesian evaluation method is proposed to integrate the ADT data from laboratory with the failure data from field. Calibration factors are introduced to calibrate the difference between the lab and the field conditions so as to predict a product's actual field reliability more accurately. The information fusion and statistical inference procedure are carried out through a Bayesian approach and Markov chain Monte Carlo methods. The proposed method is demonstrated by two examples and the sensitivity analysis to prior distribution assumption