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Cui Xiangyang,Zheng Gang,Li Guangyao 한국소성가공학회 2010 기타자료 Vol.2010 No.6
This paper presents an efficient triangular shell element based on edge-based smoothing technique for sheet forming simulation. The sheet model is first discretized into a set of triangular elements and linear shape functions are used. The smoothing domains associated with the edges of the triangles are then further formed and an edge local coordinate system is introduced for performing strain smoothing operations. The discretized system equations are obtained using the smoothed Galerkin weak form, and the numerical integration is applied based on the edge-based smoothing domains. The smoothing operation can provide a much needed softening effect to the FEM model to reduce the well-known “overly-stiff” behavior caused by the fully-compatible implementation of the displacement approach based on the Galerkin weak form, and hence improve significantly the solution accuracy. There is no extra sampling point introduced to evaluate the stiffness matrix in present formulation. Hence the present method is very simple and can be easily implemented. Some academic examples and benchmark tests show the accuracy and efficiency of the proposed element.
Junchao Xu,Xiangyang Zhang,Yunlan Sun,Hongming Long,Zhimin Zheng 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.12
Pyrolysis is a very potential sludge treatment technology that is low-cost and environmentally friendly; particularly, the pyrolysis sewage sludge char (SC) can be used as a catalyst support. To improve the NO conversion efficiency of sludge char based catalysts, they were activated by potassium hydroxide and phosphoric acid, respectively. The catalysts of activated sludge char with or without Mn-Ce impregnation in the application of NO removal by lowtemperature SCR were investigated. The higher NO conversion efficiency of sludge char based Mn-Ce catalysts at low temperature were obtained. Compared with the 59% NO conversion efficiency of Mn-Ce/SC catalyst, the conversion efficiency of catalyst supported on KOH activated char (SCK) achieved 89% at 220 oC and of catalyst supported on H3PO4 activated char (SCP) reached 87% at 240 oC. The catalysts were analytically characterized using N2 adsorptiondesorption, XRD, FTIR, NH3-TPD and XPS measurements. The higher specific area, excellent dispersion of Mn-CeOx and more Brønsted acid sites are responsible for the higher NO conversion efficiency of Mn-Ce/SCK, while the higher NO conversion efficiency of Mn-Ce/SCP is enhanced by more Brønsted acid sites, oxygen-containing and some unique phosphorus-containing oxygen functional groups. It indicates that sludge char activated by KOH and H3PO4 is a potential low-temperature catalyst support.
The Improvement of China’s Nuclear Safety Supervision Technical Support Ability
Han Wu,Guoxin Yu,Xiangyang Zheng,Keyan Teng 한국방사성폐기물학회 2022 방사성폐기물학회지 Vol.20 No.4
The International Atomic Energy Agency (IAEA) entails independent decision-making for the safety supervision of civil nuclear facilities. To evaluate and review the safety of nuclear facilities, the national regulatory body usually consults independent institutions or external committees. Technical Support Organizations (TSOs) include national laboratories, research institutions, and consulting organizations. Support from professional organizations in other countries may also be required occasionally. Most of the world’s major nuclear power countries adopt an independent nuclear safety supervision model. Accordingly, China has continuously improved upon the construction of such a system by establishing the National Nuclear Safety Administration (NNSA) as the decision-making department for nuclear and radiation safety supervision, six regional safety supervision stations, the Nuclear and Radiation Safety Center (NSC), a nuclear safety expert committee, and the National Nuclear and Radiation Safety Supervision Technology R&D Base, which serves as the test, verification, and R&D platform for providing consultation and technical support. An R&D system, however, remains to be formed. Future endeavors must focus on improving the technical support capacity of these systems. As an enhancement from institutional independence to capability independence is necessary for ensuring the independence of China’s nuclear safety regulatory institution, its regulatory capacity must be improved in the future.