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Beijing, China

Liu B.,CAS Wuhan Institute of Rock and Soil Mechanics | Gong L.,Chinergy Co. | Song Q.,CAS Wuhan Institute of Rock and Soil Mechanics
Applied Mechanics and Materials | Year: 2013

Combined with the dynamic compaction example of a nuclear power plant, a fully field tests was conducted to get the permeability and integrality of the impervious wall in real time. The dynamic compaction vibration impact on impervious wall was researched based on the test results. The relationships between damage characteristic and peak particle velocity of impervious wall are suggested also. The safety control standards which used vibration safety threshold to control the potential damage for impervious wall under long-term dynamic compaction were presented. When the PPV of impervious wall is not exceeding the safety threshold, the impervious wall will in its secured state. According to the damage detection method and the presented safety threshold of vibration velocity, the protected structure can be simply and protected during dynamic compaction. The research methods reflects the damage of protected structure directly, and more accurate and safety than traditional methods. © (2013) Trans Tech Publications, Switzerland.

Li D.-Y.,Beijing University of Technology | Sun Y.-L.,Chinergy Co. | Li Y.,Beijing University of Technology | Yan W.-M.,Beijing University of Technology
Gongcheng Lixue/Engineering Mechanics | Year: 2014

In order to study the load bearing and deformation capacity of a large-span half steel-plate-reinforced concrete (HSC) beam, a static test of a scaled down (1:3) simply supported specimen is conducted. The mechanical characteristics and damage process of the HSC specimen are investigated by analyzing the development of the deflection, strain and fracture during loading process. Good combination action is observed during the test in steel plates, reinforcing bars and concrete in HSC beam; and the specimen has good mechanical properties of high bearing capacity, large stiffness and high ductility. At last, the calculation formulae for the bending capacity and short-term stiffness of the composite beam in existing codes are examined via the experimental results and theoretical analysis, which provides a reference for engineering design.

Liu S.,North China Electrical Power University | Wang Z.,North China Electrical Power University | Sun C.,Chinergy Co.
Dianwang Jishu/Power System Technology | Year: 2011

The calculation results of three-dimensional electric field of valve tower in DC converter station plays important directive role in the design of shielding case for valve towers and the control of its surface field intensity. However, due to its enormous volume and complex structure, there are difficulties in the geometrical modeling and digital simulation of shielding case for valve tower. To save computing resource, firstly utilizing ANSYS parametric design language (APDL) an integral dissection model is built; then by use of Galerkin indirect boundary element the electric field intensity at the surface of shielding case is analyzed and the distribution of three-dimensional electric field at the surface of shielding case is calculated. Calculation results show that under current design scheme the maximum field intensity at the surface of shielding case is 20.2 kV/cm, so if the value of 30 kV/cm is taken as the criterion for corona onset field intensity, there is no corona on the shielding case. This criterion is available for reference in the design and planning of shielding case for valve tower in DC converter station.

Huang X.,Harbin Institute of Technology | Gao D.,Harbin Institute of Technology | Cong Y.,Chinergy Co. | Wang X.,Harbin Institute of Technology
Shengwu Gongcheng Xuebao/Chinese Journal of Biotechnology | Year: 2014

An expanded-granular sludge bed (EGSB) reactor was set-up with artificial water by seeding a 60 d stored ANAMMOX sludge. The nitrogen removal efficiency of ANAMMOX enrichment culture in the reactor was determined. In addition, the main microbial populations and the relative abundance of ANAMMOX bacteria were investigated by molecular approaches. Results show that the maximum nitrogen removal rate was 3.0 kg-N·m-3·d-1 after 185 d, and the ammonium and nitrite removal efficiencies were all over 85%. Analysis of 16S rRNA gene-cloning indicates that the main microbial population in the ANAMMOX enrichment culture was changed from Candidatus Brocadia fulgid and Candidatus Brocadia brasiliensis (0 day) to Candidatus Jettenia asiatica (185 day). Fluorescence in situ hybridization analysis shows that the relative abundance of ANAMMOX bacteria was increased from (57.69±4.79)% to (83.32±4.40)%. The results of qPCR further indicate that the gene copies of ANAMMOX bacteria in the granules were increased from 1.14×1011 copies/g wet weight to 3.69×1011 copies/g wet weight. ©2014 Chin J Biotech, All rights reserved.

Shen K.,Cooperation Technology | Su J.,Cooperation Technology | Zhou H.,Cooperation Technology | Zhou H.,Chinergy Co. | And 3 more authors.
Nuclear Engineering and Design | Year: 2015

A pebble-bed higherature gas-cooled reactor (pebble-bed HTR) uses a helium coolant, graphite core structure, and spherical fuel elements. The pebble-bed design enables on-line refueling, avoiding refueling shutdowns. During circulation process, the pebbles are lifted pneumatically via a stainless steel lifting pipe and reinserted into the reactor. Inevitably, the movement of the fuel elements as they recirculate in the reactor produces graphite dust. Mechanical wear is the primary source of graphite dust production. Specifically, the sources are mechanisms of pebble-pebble contact, pebble-wall (structural graphite) contact, and fuel handling (pebble-metal abrasion). The key contribution to graphite dust production is from the fuel handling system, particularly from the lifting pipe. During pneumatic lift, graphite pebbles undergo multiple collisions with the stainless steel lifting pipe, thereby causing abrasion of the graphite pebbles and producing graphite dust. The present work explored the abrasion behavior of graphite pebble in the lifting pipe by measuring the abrasion rate at different lifting velocities. The abrasion rate of the graphite pebble in helium was found much higher than those in air and nitrogen. This gas environment effect could be explained by either tribology behavior or dynamic behavior. Friction testing excluded the possibility of tribology reason. The dynamic behavior of the graphite pebble was captured by analysis of the audio waveforms during pneumatic lift. The analysis results revealed unique dynamic behavior of the graphite pebble in helium. Oscillation and consequently intensive collisions occur during pneumatic lift, causing significant abrasion of the graphite pebble. This study provides an excellent explanation for the abrasion behavior of graphite pebbles in the lifting pipe of the pebble-bed HTR. © 2015 Elsevier B.V. All rights reserved.

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