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1. Research progress of cement radioactivity in China | |||
Wang Feng,Wu Chuncen,Zhang Xiuqin,Song Yifan,Geng Shang,Wu Zhong,Wang Guoqiang,Sun Yuan-nan | |||
Nuclear Science and Technology 06 March 2024 | |||
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Abstract:Cement, as one of the fundamental building materials, often incorporates industrial solid waste or byproducts as alternative raw materials. Some of these materials contains natural radioactivity at higher levels. Inadequate control of the quantity of these materials can potentially result in prolonged exposure to high levels of radioactivity, posing potential threats to health. This paper provides a comprehensive analysis of radioactivity in cement, including the influence of raw and auxiliary materials on cement radioactivity, release of radioactive nuclides during production, the assessment of radio-nuclide levels in various cement types, and the uncertainty related to radioactivity measurements. The main goal of this study is to begin monitoring natural radioactivity levels at the source of cement production and offer relevant production recommendations for the cement industry. Furthermore, it emphasizes the need for future research to focus on monitoring the natural radioactivity levels of various industrial byproducts used as alternative raw materials, while simultaneously enhancing relevant standards and regulations. This will contribute to ensuring environmental safety in cement production and mitigating potential health risks. | |||
TO cite this article:Wang Feng,Wu Chuncen,Zhang Xiuqin, et al. Research progress of cement radioactivity in China[OL].[ 6 March 2024] http://en.paper.edu.cn/en_releasepaper/content/4762394 |
2. Evaluation of interfacial properties in SiC composites using an improved cohesive element method | |||
ZANG Hang,CAO Xingqing,HE Chaohui,HUANG Zhisheng,LI Yonghong | |||
Nuclear Science and Technology 17 April 2017 | |||
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Abstract:A two-dimensional axisymmetric finite element model based on an improved cohesive element method was developed to simulate the the interfacial debonding, the sliding friction and residual thermal stresses of SiC composites during single fiber push-out test to extract the interfacial bond strength and frictional stress. The numerical load-displacement curves agree well with the experimental curves, indicating that this cohesive element can be used for calculating the interfacial properties of SiC composites. The simulation results show that the crack is most likely to occur at both ends of the experiment, where the maximum shear stress is observed, and the interfacial shear strength and the constant sliding friction stress decrease with an increase of temperature. Moreover, the load required to cause a complete failure of the interface is with the increase of shear strength and composite material with higher fiber volume fraction has stronger bearing capacity. In addition, the initial failure load becomes stronger with an increase of interphase thickness. | |||
TO cite this article:ZANG Hang,CAO Xingqing,HE Chaohui, et al. Evaluation of interfacial properties in SiC composites using an improved cohesive element method[OL].[17 April 2017] http://en.paper.edu.cn/en_releasepaper/content/4725456 |
3. Cold leg break LOCA Analysis for Canadian-SCWR with passive safety system | |||
CHAO Fei,YUAN Yuan,WU Pan,SHAN Jianqiang,GOU Junli | |||
Nuclear Science and Technology 09 May 2016 | |||
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Abstract:Safety analysis is an important issue in SuperCritical Water Reactor concept development. Loss of coolant accident is one of the most important accident which should be treated seriously. The cold leg break LOCA analyses are carried out in this paper to evaluate the feasibility of Canadian SCWR. Passive safety systems, such as automatic depressurization system, accumulator and gravity driven cooling system are applied to mitigate the LOCA consequence. The following conclusions are achieved:1) two cladding temperature peaks will appear in the process of cold leg break LOCA. The discharge flowrate through cold leg break is favourable to decrease the first cladding temperature peak. Automatic depressurization system can decrease the second cladding temperature peak effectively. The first peak cladding temperature in 25% break case is higher than that in 100% break case, while the second peak cladding temperature in 25% break case is lower than that in 100% break case. 2) The peak cladding temperatures of Canadian SCWR with passive safety system under cold leg break LOCA stay below the temperature criterion. | |||
TO cite this article:CHAO Fei,YUAN Yuan,WU Pan, et al. Cold leg break LOCA Analysis for Canadian-SCWR with passive safety system[OL].[ 9 May 2016] http://en.paper.edu.cn/en_releasepaper/content/4687309 |
4. Commissioning of the LLRF control system for DC-SRF photo-injector | |||
WANG Fang,FENG Liwen,LIN Lin | |||
Nuclear Science and Technology 17 November 2015 | |||
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Abstract:DC-SRF photo-injector, which can be operated in continuous wave (CW) and pulse mode, was firstly proposed and developed by Peking University. It combines a 1.3 GHz 3+1/2-cell superconducting cavity working at 2 K. Due to the thin walled structure and narrow bandwidth, the superconducting cavity is very susceptible to mechanical perturbations which induces significant amplitude and phase errors and resulting in electron beam quality degradation. In the paper, the parameters of the proportional-integral (PI) controller are optimized in MATLAB and a new controller is presented and simulated in Simulink to deal with the Lorentz force detuning during the filling stage of the cavity in pulse mode. The digital low level radio frequency (LLRF) control system is improved and accomplished based on the new controller, the amplitude and phase stability of the 3+1/2-cell superconducting cavity in pulse mode achieve 0.13% and 0.1 respectively, and it runs stably during the high repetition terahertz radiation experiments based on the DC-SRF photo-injector. | |||
TO cite this article:WANG Fang,FENG Liwen,LIN Lin. Commissioning of the LLRF control system for DC-SRF photo-injector[OL].[17 November 2015] http://en.paper.edu.cn/en_releasepaper/content/4661619 |
5. Proposal of a new fuel assembly design for supercritical water cooled reactor | |||
LIU Xiaojing,CHENG Xu | |||
Nuclear Science and Technology 05 May 2014 | |||
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Abstract:The supercritical water cooled reactor (SCWR) is a Light Water Reactor (LWR) operating at higher pressure and temperature. Operation above the critical pressure eliminates coolant boiling phenomenon so that the coolant remains single-phase throughout the reactor. Due to its high thermal efficiency and economical competitiveness, SCWR has achieved significant interests of nuclear industries and research institutions. R&D programs have been launched worldwide to study the phenomena involved in SCWR. Design of fuel assemblies of thermal SCWR is one of the main challenging tasks due to: complicated fuel assembly configurations and strong coupling effect of thermal-hydraulics with neutron-kinetics. Although a large number of fuel assembly designs have been proposed, no agreement has been achieved. Further activities are thus needed to develop reliable numerical analysis tools and to propose and assess new fuel assembly designs. In the present paper, new design concepts of SCWR fuel assembly were proposed. The thermal-hydraulic performance and neutron-physical behavior of the new fuel assemblies were investigated using the newly developed coupled code. The results achieved so far indicate the new fuel assembly design has a more uniform distribution of the power density and the coolant temperature compared to the previous ones. | |||
TO cite this article:LIU Xiaojing,CHENG Xu. Proposal of a new fuel assembly design for supercritical water cooled reactor[OL].[ 5 May 2014] http://en.paper.edu.cn/en_releasepaper/content/4595492 |
6. The Radioactive Source Distribution Calculation and Gauging Nonlinear Correction of Multi-point Source Nuclear Gauge Based on the Numeric Analysis Method | |||
Cheng Xiaolong,Zhao Xiuliang | |||
Nuclear Science and Technology 20 February 2013 | |||
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Abstract:The nuclear material level gauge with approximate linear scale is realized by the numerical analysis method. In this paper, according to the real project design a theoretical calculation model, using the multipoint combination source and single detector measurement scheme. Referencing the line-source design method, calculate the multipoint combination source activity which satisfy the measurement range and accuracy requirement, and through the Excel and Matlab software complete the data calculation and dispose, drawing out the count rate - material level diagram. According to the nonlinear measurement, use the equivalent point source method, compensating the bottom source activity and residual analysis method , revise the gauging nonlinear separately. Finally complete the theoretical design of multipoint source nuclear material level gauge with the total source activity of 633mCi, measurement range 80cm, 5mm measurement precision and response time 14-33S.Through the protective calculation, do the comprehensive analysis for the three ways, confirm the residual analysis as the best design scheme. | |||
TO cite this article:Cheng Xiaolong,Zhao Xiuliang. The Radioactive Source Distribution Calculation and Gauging Nonlinear Correction of Multi-point Source Nuclear Gauge Based on the Numeric Analysis Method[OL].[20 February 2013] http://en.paper.edu.cn/en_releasepaper/content/4519384 |
7. Fabrication and characterization of Ag-implantation modificated TiO2 films followed with thermal annealing | |||
Xiao Xiangheng,Xu Jinxia,Ren Feng,Cai Guangxu | |||
Nuclear Science and Technology 12 January 2013 | |||
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Abstract:TiO2 thin films fabricated by direct-current (DC) reactive magnetron sputtering were implanted with Ag ions at 30 kV to fluences of 1×1016, 3×1016 and 5×1016 ions/cm2, and subsequently annealed at 500 C for 2 h under Ar ambient. Cross-sectional transmission electron microscopy and X-ray photoelectron spectroscopy studies showed that the implanted Ag ions were incorporated in TiO2 to form Ag2O after thermal annealing. The Ag-implanted TiO2 film with fluence of 3×1016 ions/cm2 after an annealing showed improved photocatalytic efficiency comparing to TiO2 film. When the implantation fluence increased to the 5×1016 ions/cm2, the sample showed poorer phtotcatalytic efficiency. These results indicate that there exists an optimum Ag ions implantation fluence. The photocatalytic behavior can be explained by the effect of Ag+ on the physicochemical properties in terms of electronic structures and film texture. | |||
TO cite this article:Xiao Xiangheng,Xu Jinxia,Ren Feng, et al. Fabrication and characterization of Ag-implantation modificated TiO2 films followed with thermal annealing[OL].[12 January 2013] http://en.paper.edu.cn/en_releasepaper/content/4514747 |
8. Tuning porous silica films by various surfactants and loading: A study of positron annihilation Doppler broadening based on a slow positron beam | |||
XIONG Bangyun,MAO Wenfeng,HE Chunqing | |||
Nuclear Science and Technology 25 October 2012 | |||
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Abstract:Porous silica films were synthesized via a sol-gel method using a nonionic amphiphilic triblock copolymer (F127) and a cationic surfactant (CTAB) as the structural templates with varying weight ratio. Positron annihilation Doppler broadening spectroscopy based on a slow positron beam was used to study the prepared silica films. For the porous silica films, the S parameter increased gradually with increasing the surfactant loading, which showed that larger pores were introduced in the silica films with more porogen. Distinct difference was observed for the W parameter of the same silica film templated by CTAB after rotating it by 90 around the positron beam axis, indicative of ordered tubal pores aligning along the film surface. | |||
TO cite this article:XIONG Bangyun,MAO Wenfeng,HE Chunqing. Tuning porous silica films by various surfactants and loading: A study of positron annihilation Doppler broadening based on a slow positron beam[OL].[25 October 2012] http://en.paper.edu.cn/en_releasepaper/content/4492969 |
9. Grating-based X-ray Tomosynthesis on Biological Sample | |||
Ran Zhang,Zhiqiang Chen,Li Zhang,Xiaolei Jiang,Hongxia Yin,Zhenchang Wang | |||
Nuclear Science and Technology 04 June 2012 | |||
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Abstract:X-ray grating-based imaging can provide additional contrast mechanisms other than absorption, namely (differential) phase shift and small-angle scattering. For many biological samples which have poor absorption contrast, the (differential) phase shift and small-angle scattering contrast may provide useful information. Tomosynthesis is a three-dimensional reconstruction technique that aims to separate the overlapping structure of the object with a few projections from a limited angle. In this work, grating-based tomosynthesis with synchrotron radiation source has been performed. Tomosynthetic results using both analytical and iterative reconstruction methods have been compared. It is seen from the results that images reconstructed using iterative method with total variation constraint have better visual effect. | |||
TO cite this article:Ran Zhang,Zhiqiang Chen,Li Zhang, et al. Grating-based X-ray Tomosynthesis on Biological Sample[OL].[ 4 June 2012] http://en.paper.edu.cn/en_releasepaper/content/4479879 |
10. Three-image-based multiple information retrieval algorithm for X-ray Grating-based Imaging | |||
JIANG Xiaolei,HUANG Zhifeng | |||
Nuclear Science and Technology 15 September 2011 | |||
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Abstract:Hard X-ray grating-based imaging has the most potential in clinical applications because it works well with conventional X-ray tubes and provides multiple information (absorption, refraction and scattering) simultaneously. However, grating-based imaging adopts a series of images to retrieve multiple information, which significantly increases the exposure time and doses compared with conventional X-ray imaging. In this paper, we propose an optimized three-image-based multiple information retrieval (TIB-MIR) algorithm for low-dose grating-based imaging. The errors of the retrieval information are minimal in the case of three steps with equal intervals of within one period, which is equivalent to the 3-step fringe-scanning algorithm. Furthermore, in the case of Poisson noise model and equal doses, the method can obtain equivalent image quality compared with fringe-scanning method. | |||
TO cite this article:JIANG Xiaolei,HUANG Zhifeng. Three-image-based multiple information retrieval algorithm for X-ray Grating-based Imaging[OL].[15 September 2011] http://en.paper.edu.cn/en_releasepaper/content/4443102 |
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