ISSN 0253-2778

CN 34-1054/N

2017 Vol. 47, No. 6

Display Method:
Original Paper
On the explicit expression of a conformal metric of constant curvature one near a conical singularity
FENG Yu, SHI Yiqian, XU Bin
2017, 47(6): 455-458. doi: 10.3969/j.issn.0253-2778.2017.06.001
Near a conical singularity with angle 2πα>0 of a conformal metric of constant curvature one, it was proved by using the developing map that there exists a suitable complex coordinate z under which the metric has the expression of 
A class of projectively flat and dually flat Finsler metrics
HE Chao, LI Ying, SONG Weidong
2017, 47(6): 459-464. doi: 10.3969/j.issn.0253-2778.2017.06.002
Finsler geometry is just Riemannian geometry without quadratic restriction, and the projectively flat and dually flat Finsler metrics are very important in Finsler geometry. Here a class of 3-parameter of Finsler metrics were studied, and the necessary and sufficient conditions for the Finsler metrics to be projectively flat and dually flat were obtained.
Design of a novel simplified dodecapole field magnet
LUO Huanli, WANG Xiangqi, LI Xiang, TANG Jingyu, YANG Zheng, XIE Kai
2017, 47(6): 465-473. doi: 10.3969/j.issn.0253-2778.2017.06.003
Beam distribution with the regular and homogeneous form on spallation target or beam dump is an imperious demand for spallation neutron source (SNS), accelerator driven sub-critical system (ADS), and so on. Nowadays, adopting nonlinear antisymmetric high order field is very infusive for distribution transformation of beam. Here, a simplified dodecapole field magnet (SDFM), well focusing particles in beam halo to inner layer of beam halo or beam core, was introduced. Combining SDFM with antisymmetric sextupole, octupole or decapole magnet can theoretically get approximate uniformly distributed round beam with slightly larger size. The conceptual design, physics structural and its manufacturing method of SDFM was presented.
Readout system of THGEM position-sensitive detector
ZHAO Yafei, HUA Renjun, JI Weitian, CHEN Ziyu, SHEN Ji
2017, 47(6): 474-478. doi: 10.3969/j.issn.0253-2778.2017.06.004
Based on THGEM thermal neutron position sensitive detector, a readout electronics system was designed with a specific integrated chip VA64TA2 to realize charge integration, amplification and conversion. Using high-speed analog-to-digital conversion chip AD9220 to realize data sampling, USB communication to realize data transmission, and FPGA as the main controller, the system was constructed. The array charge signal readout of the detector was realized. The channel input-output linear responses of the system are good, between ±15 fc. The centre-of-gravity read-out of position information was realized. The maximum counting rate of the detector could reach 1×105/s.
Investigation into the In-box LOCA of water cooled solid breeder blanket for CFETR based on PWR conditions
YANG Xiao, ZHAO Pinghui, GE Zhihao, LI Yuanjie, NIE Xingchen, LIU Jiaming
2017, 47(6): 479-484. doi: 10.3969/j.issn.0253-2778.2017.06.005
China Fusion Engineering Testing Reactor(CFETR)is an “ITER-like” DEMO fusion reactor in China. As one of the breeding blanket candidates for CFETR, a water cooled breeder blanket based on PWR conditions has been designed. Here In-box LOCA of water cooled solid breeder blanket for CFETR based on PWR conditions was investigated by RELAP5/MOD3.4. The accident’s processes were described in detail and its results were analyzed preliminarily.According to the computational results, first wall (FW) does not melt and the production of hydrogen is lower than the limit. Meanwhile, due to the rupture disk, the flow can vent into the vacuum vessel(VV) after the accident, which ensures the integrity of the blanket. And due to the large volume of the VV, the final pressure of VV is much lower than the limit.
Effects of corrosion on tensile property of 316L fiber felt in lead bismuth eutectic
LI Wenkai, ZHOU Xiaojiao, HUANG Hua, GAO Sheng
2017, 47(6): 485-490. doi: 10.3969/j.issn.0253-2778.2017.06.006
Based on the operation environment of China Lead-based Research Reactor (CLEAR-I), the tensile properties of filter material-sintered 316L fiber felt exposed to stagnant lead bismuth eutectic (LBE) with 1×10-6 wt% oxygen concentration was investigated at 500℃ for 500 h, 1000h, 1500 h. The results showed that compared to the original fiber felt, the tensile strength of the fiber felts decreased to 67%, 33% and 15% after 500 h, 1000 h and 1500 h, respectively. It was found that the binding strength of the joints and diameter of 316L stainless steel fibers gradually decreased with exposure time due to the compact single-layer (Fe,Cr)3O4 spinel formation on 316L fibers, which was the main cause of tensile strength of sintered 316L fiber felt dropping after LBE corrosion.
Coupled thermo-mechanical and fracture analysis of a nuclear reactor pressure vessel
SUN Xin, CHAI Guozhong, BAO Yumei
2017, 47(6): 491-497. doi: 10.3969/j.issn.0253-2778.2017.06.007
To study the influence of pressurized thermal shock on the bearing capacity of the nuclear reactor pressure vessel (RPV) with a surface crack, the 3D finite element model was established for the beltline region around the crack by ABAQUS software. The transient temperature field and stress field were obtained. The XFEM was used to simulate the crack propagation in the thermo-mechanical coupling field. The ultimate bearing capacity of the vessel at different nil-ductility transition temperatures was tested employing elastic-plastic fracture analysis, and the results were compared with those obtained from elastic analysis to sum up the fracture characteristics of the material. Through mesh refinement, it was found that the crack propagation paths and the damage degrees for different element sizes are equivalent, which avoids pathological mesh dependence.
Effect of bolt joints on behaviour of transmission tower under external loads
YE Min, CHEN Haibo, ZHANG Huiwu, ZHAO Xiuzhen
2017, 47(6): 498-507. doi: 10.3969/j.issn.0253-2778.2017.06.008
To ensure the safe operation of transmission lines, it is necessary to convert metecorological conditions to equvalent external forces in simulation calculations in the design process of transmission tower. The traditional structural finite element analysis methods usually simplify the bolt joints of steel angles as rigid or pinned connections,ignoring the effect of slip and eccentricity. Using ANSYS software, on the basis of an original slip model, an improved slip model was built by further considering bolt joints in tower legs and tower head. Simulation results were compared with the original slip model and two conventional models. The rationality of the model was verified by the dynamic and static measurements of the full scale tower test, enabling the investigation of responses of the maximal working load conditions. It could be found that, the improved slip model optimizes the forecast of the bending modal frequencies and accurately simulates the real deformation and axial force of the transmission tower. The effect of bolt joints is related to the load combination conditions. Consideration of the effect of bolt joints in tower legs and tower head is necessary to the analysis of the most dangerous condition: wire breakage.
Empirical study on the impact of third-party logistics service quality on customer loyalty
YUAN Wei, Fan Jin, ZHAO Dingtao, ZHANG Minxian
2017, 47(6): 508-513. doi: 10.3969/j.issn.0253-2778.2017.06.009
Third-party logistics tends to make direct contact with customers on behalf of e-commerce business when the logistics is outsourced, and the quality of its service is thus of great importance to study impacts on customer loyalty. A logistics service quality-customer loyalty model (LSQ-CL model) was built to measure the impacts of third-party logistics on customer loyalty. Using the structural equation model, data from 459 third-party logistics users was used to conduct a confirmatory factor analysis. The results show that operational service quality, relational service quality and cost quality all have significant positive impacts on customer satisfaction, among which operational service quality is the most influential, followed by relationship service quality, and cost quality has the least impact. Relational service quality has significant positive impacts both on operational service quality and cost quality. Customer satisfaction has a significant impact on customer loyalty, and there is a large path coefficient between them.
Analysis of the evolutionary game of reward-based crowdfunding platforms and entrepreneurs
DENG Biteng, ZHAO Zheng
2017, 47(6): 514-523. doi: 10.3969/j.issn.0253-2778.2017.06.010
To investigate the selection mechanism of the reward-based crowdfunding platform operation mode, a game model was developed by employing the evolutionary game theory. With this model the evolutionary dynamic stability of the selection for every stakeholder’s strategy was analyzed, and critical factors that determine the selection mechanism of the reward-based crowdfunding platform operation mode were explored by means of numerical simulation. The main result indicates that the key factor influencing the selection mechanism contains the following five dimensions: entrepreneurs’ demand for financing, crowdfunding platform service rates, service efficiency of the crowdfunding platform, opportunity cost of the crowdfunding platform to provide high quality services and government regulation of the reward-based crowdfunding market.
The economic effect of discretionary fiscal policy research under the new normal based on the perspective of market sentiment volatility
YANG Zhaoliang, CUI ZhiKun
2017, 47(6): 524-529. doi: 10.3969/j.issn.0253-2778.2017.06.011
Establishing the models of GARCH and TGARCH based on related data collected through three variables, the growth rate of urban investment, the cumulative growth rate of fiscal expenditure, and the year-on -year growth rate of fiscal expenditure and broad money supply, the impacts of market volatility on investment behavior in the process of implementing fiscal policies was studied, and the effect of the fiscal policies under the new economic normal was further analyzed. The results show that the implementation of fiscal policies has a crowding-out effect on private investment, but the resulting space is limited. Fiscal policies act synergistically with monetary policies for the enforcement of fiscal policies stimulates the increase of investment instead. In the process of policy implementation, the influence of market sentiment on investment behavior is lasting, which decreases gradually over time and has an important reference value for future projections. When the negative news affects market sentiment, the implementation of fiscal policies weakens the effect of negative factors on the investment fluctuations; as the economy steps into the new normal, investor behavior tends to be cautious due to the slow pace of economic development.
Supply chain with wholesale price contract under inequity aversion and random yield
LAN Chongfeng, BI Gongbing, FEI Yalei
2017, 47(6): 530-540. doi: 10.3969/j.issn.0253-2778.2017.06.012
The effect of inequity aversion on supply chain with random yield and random demand was studied. Based on disadvantageous inequity aversion and advantageous inequity aversion, a model of wholesale price contract with random yield and random demand was established, the optimal ordering quantity of the retailer in different situations was obtained and the influence of fairness preferences on retailer’s optimal ordering quantity and supply chain coordination was analyzed. Finally, numerical examples were presented to illustrate the theoretical results. This research shows that the wholesale price contract can not achieve supply chain coordination for the fair neutral retailer. However, when the retailer has extreme advantageous inequity aversion, the wholesale price contract can improve the profit of the whole supply chain and better coordinate the supply chain, which extends the theory and application of the traditional wholesale price contract in real life.