One of the most important aims of this study is to improve the core of the current VVER reactors to achieve more burn-up(or more cycle length)and more intrinsic safety.It is an independent study on the Russian new pro...One of the most important aims of this study is to improve the core of the current VVER reactors to achieve more burn-up(or more cycle length)and more intrinsic safety.It is an independent study on the Russian new proposed FAs,called TVS-2M,which would be applied for the future advanced VVERs.Some important aspects of neutronics as well as thermal hydraulics investigations(and analysis)of the new type of Fas are conducted,and results are compared with the standards PWR CDBL.The TVS-2M FA contains gadolinium-oxide which is mixed with UO_(2)(for different Gd densities and U-235 enrichments which are given herein),but the core does not contain BARs.The new type TVS-2M Fas are modeled by the SARCS software package to find the PMAXS format for three states of CZP and HZP as well as HFP,and then the whole core is simulated by the PARCS code to investigate transient conditions.In addition,the WIMS-D5 code is suggested for steady core modeling including TVS-2M FAs and/or TVS FAs.Many neutronics aspects such as the first cycle length(first cycle burn up in terms of MWthd/kgU),the critical concentration of boric acid at the BOC as well as the cycle length,the axial,and radial power peaking factors,differential and integral worthy of the most reactive CPS-CRs,reactivity coefficients of the fuel,moderator,boric acid,and the under-moderation estimation of the core are conducted and benchmarked with the PWR CDBL.Specifically,the burn-up calculations indicate that the 45.6 d increase of the first cycle length(which corresponds to 1.18 MWthd/kgU increase of burnup)is the best improving aim of the new FA type called TVS-2M.Moreover,thermal-hydraulics core design criteria such as MDNBR(based on W3 correlation)and the maximum of fuel and clad temperatures(radially and axially),are investigated,and discussed based on the CDBL.展开更多
Small long-life transportable high temperature gas-cooled reactors(HTRs) are interesting because they can safely provide electricity or heat in remote areas or to industrial users in developed or developing countries....Small long-life transportable high temperature gas-cooled reactors(HTRs) are interesting because they can safely provide electricity or heat in remote areas or to industrial users in developed or developing countries.This paper presents the neutronic design of the U-Battery,which is a 5 MWth block-type HTR with a fuel lifetime of 5–10 years.Assuming a reactor pressure vessel diameter of less than 3.7 m,some possible reactor core configurations of the 5 MWth U-Battery have been investigated using the TRITON module in SCALE 6.The neutronic analysis shows that Layout 12×2B,a scattering core containing 2 layers of 12 fuel blocks each with 20% enriched235U,reaches a fuel lifetime of 10 effective full power years(EFPYs).When the diameter of the reactor pressure vessel is reduced to 1.8 m,a fuel lifetime of 4 EFPYs will be achieved for the 5 MWth U-Battery with a 25-cm thick graphite side reflector.Layouts 6×3 and 6×4 with a 25-cm thick BeO side reflector achieve a fuel lifetime of 7 and 10 EFPYs,respectively.The comparison of the different core configurations shows that,keeping the number of fuel blocks in the reactor core constant,the annular and scattering core configurations have longer fuel lifetimes and lower fuel cost than the cylindrical ones.Moreover,for the 5 MWth U-Battery,reducing the fuel inventory in the reactor core by decreasing the diameter of fuel kernels and packing fraction of TRISO particles is more effective to lower the fuel cost than decreasing the 235U enrichment.展开更多
This article presents the network design schemes of CERNET2 including overall architecture, the backbone, core nodes, access solutions and the CNGI peer centers. CERNET2 connects 25 core nodes distributed in 20 cities...This article presents the network design schemes of CERNET2 including overall architecture, the backbone, core nodes, access solutions and the CNGI peer centers. CERNET2 connects 25 core nodes distributed in 20 cities of China at the speed of 2.5-10 Gb/s. CERNET2 has four unique features. First, its backbone adopts native IPv6 protocols, rather than IPv4/IPv6 dual stack. It is the largest pure IPv6 network in the world. Second, it provides an environment for testing and trial operation of China-made IPv6 core routers. It also allows tests of interconnection, interworking and interoperation among multiple vendors. Third, the large IPv6 address space enables the study on network addresses in a real network environment, which ensures the construction of a secured and trusted CNGI. Last, it is a test-bed for NGI applications.展开更多
Based on the method of compound and additional conditions under the conditions of the equal temperature rise and the equal potential drop (P.D.) of resistance, the application of design software of dry-type air-core r...Based on the method of compound and additional conditions under the conditions of the equal temperature rise and the equal potential drop (P.D.) of resistance, the application of design software of dry-type air-core reactor is introduced in this thesis. The analytical methods of the inductance are also given. This approach is proved entirely feasible in theory through the simplification with Bartky transformation, and is able to quickly and accurately calculate reactor inductance. This paper presents the analytical methods of the loss of dry-type air-core reactor as well.展开更多
Based on the advanced integrated technology of materials preparation and formation, a new pattern Zn-Al-Mg-RE anti-corrosion coating for steel structure sustainable design was manufactured by cored wires and high velo...Based on the advanced integrated technology of materials preparation and formation, a new pattern Zn-Al-Mg-RE anti-corrosion coating for steel structure sustainable design was manufactured by cored wires and high velocity arc spraying (HVAS) technologies. The developments of thermally sprayed coatings for steel structure protection were described. Based on Al, Zn, Zn-Al and Zn-Al-Mg coatings, the anti-corrosion properties of new-pattern Zn-Al-Mg-RE coating were evaluated through electrochemical methods including electrochemical polarization and electrochemical impedance spectroscopy (EIS) coupled with SEM and XRD. The models of Zn-Al-Mg-RE coating undergoing corrosion with the initial pinhole defect and the latter with accelerated products were also discussed. The results show that Zn-Al-Mg-RE coating exhibites excellent corrosion resistance for long-term immersion, which is helpful for the sustainable design of steel structure in aggressive corrosion conditions. And the corrosion products seem to possess certain self-sealing function.展开更多
The relationships between the properties of PVC-MBS polyblend and of the MBS multiphase structure and between the MBS structure and polymerization parameters are studied theoretically and experimentally. MBS resin syn...The relationships between the properties of PVC-MBS polyblend and of the MBS multiphase structure and between the MBS structure and polymerization parameters are studied theoretically and experimentally. MBS resin synthesized from the molecule design principle is suitable to prepare PVC-MBS polyblend with good transparency and high impact strength.展开更多
Design for Testability(DFT) is critical in chip design.DFT techniques insert hardware logic to an original design,in order to improve testability of the chip,and thus reduce test cost significantly.In this paper,we in...Design for Testability(DFT) is critical in chip design.DFT techniques insert hardware logic to an original design,in order to improve testability of the chip,and thus reduce test cost significantly.In this paper,we introduces the most frequently used DFT techniques,then put emphasis on the DFT policy and the DFT realization of the NDSP25 chip core,and analyses the result at last.展开更多
Truss-core sandwich plates have received much attention in virtue of the high values of strength-to-weight and stiffness-to-weight as well as the great ability of impulseresistance recently. It is necessary to study t...Truss-core sandwich plates have received much attention in virtue of the high values of strength-to-weight and stiffness-to-weight as well as the great ability of impulseresistance recently. It is necessary to study the stability of sandwich panels under the influence of the thermal load. However, the sandwich plates are such complex threedimensional （3D） systems that direct analytical solutions do not exist, and the finite element method （FEM） cannot represent the relationship between structural parameters and mechanical properties well. In this paper, an equivalent homogeneous continuous plate is ideMized by obtaining the effective bending and transverse shear stiffness based on the characteristics of periodically distributed unit cells. The first order shear deformation theory for plates is used to derive the stability equation. The buckling temperature of a simply supported sandwich plate is given and verified by the FEM. The effect of related parameters on mechanical properties is investigated. The geometric parameters of the unit cell are optimized to attain the maximum buckling temperature. It is shown that the optimized sandwich plate can improve the resistance to thermal buckling significantly.展开更多
基金Sincere thanks are due to the Shiraz University Research Council for his financial support.
文摘One of the most important aims of this study is to improve the core of the current VVER reactors to achieve more burn-up(or more cycle length)and more intrinsic safety.It is an independent study on the Russian new proposed FAs,called TVS-2M,which would be applied for the future advanced VVERs.Some important aspects of neutronics as well as thermal hydraulics investigations(and analysis)of the new type of Fas are conducted,and results are compared with the standards PWR CDBL.The TVS-2M FA contains gadolinium-oxide which is mixed with UO_(2)(for different Gd densities and U-235 enrichments which are given herein),but the core does not contain BARs.The new type TVS-2M Fas are modeled by the SARCS software package to find the PMAXS format for three states of CZP and HZP as well as HFP,and then the whole core is simulated by the PARCS code to investigate transient conditions.In addition,the WIMS-D5 code is suggested for steady core modeling including TVS-2M FAs and/or TVS FAs.Many neutronics aspects such as the first cycle length(first cycle burn up in terms of MWthd/kgU),the critical concentration of boric acid at the BOC as well as the cycle length,the axial,and radial power peaking factors,differential and integral worthy of the most reactive CPS-CRs,reactivity coefficients of the fuel,moderator,boric acid,and the under-moderation estimation of the core are conducted and benchmarked with the PWR CDBL.Specifically,the burn-up calculations indicate that the 45.6 d increase of the first cycle length(which corresponds to 1.18 MWthd/kgU increase of burnup)is the best improving aim of the new FA type called TVS-2M.Moreover,thermal-hydraulics core design criteria such as MDNBR(based on W3 correlation)and the maximum of fuel and clad temperatures(radially and axially),are investigated,and discussed based on the CDBL.
文摘Small long-life transportable high temperature gas-cooled reactors(HTRs) are interesting because they can safely provide electricity or heat in remote areas or to industrial users in developed or developing countries.This paper presents the neutronic design of the U-Battery,which is a 5 MWth block-type HTR with a fuel lifetime of 5–10 years.Assuming a reactor pressure vessel diameter of less than 3.7 m,some possible reactor core configurations of the 5 MWth U-Battery have been investigated using the TRITON module in SCALE 6.The neutronic analysis shows that Layout 12×2B,a scattering core containing 2 layers of 12 fuel blocks each with 20% enriched235U,reaches a fuel lifetime of 10 effective full power years(EFPYs).When the diameter of the reactor pressure vessel is reduced to 1.8 m,a fuel lifetime of 4 EFPYs will be achieved for the 5 MWth U-Battery with a 25-cm thick graphite side reflector.Layouts 6×3 and 6×4 with a 25-cm thick BeO side reflector achieve a fuel lifetime of 7 and 10 EFPYs,respectively.The comparison of the different core configurations shows that,keeping the number of fuel blocks in the reactor core constant,the annular and scattering core configurations have longer fuel lifetimes and lower fuel cost than the cylindrical ones.Moreover,for the 5 MWth U-Battery,reducing the fuel inventory in the reactor core by decreasing the diameter of fuel kernels and packing fraction of TRISO particles is more effective to lower the fuel cost than decreasing the 235U enrichment.
文摘This article presents the network design schemes of CERNET2 including overall architecture, the backbone, core nodes, access solutions and the CNGI peer centers. CERNET2 connects 25 core nodes distributed in 20 cities of China at the speed of 2.5-10 Gb/s. CERNET2 has four unique features. First, its backbone adopts native IPv6 protocols, rather than IPv4/IPv6 dual stack. It is the largest pure IPv6 network in the world. Second, it provides an environment for testing and trial operation of China-made IPv6 core routers. It also allows tests of interconnection, interworking and interoperation among multiple vendors. Third, the large IPv6 address space enables the study on network addresses in a real network environment, which ensures the construction of a secured and trusted CNGI. Last, it is a test-bed for NGI applications.
文摘Based on the method of compound and additional conditions under the conditions of the equal temperature rise and the equal potential drop (P.D.) of resistance, the application of design software of dry-type air-core reactor is introduced in this thesis. The analytical methods of the inductance are also given. This approach is proved entirely feasible in theory through the simplification with Bartky transformation, and is able to quickly and accurately calculate reactor inductance. This paper presents the analytical methods of the loss of dry-type air-core reactor as well.
文摘Based on the advanced integrated technology of materials preparation and formation, a new pattern Zn-Al-Mg-RE anti-corrosion coating for steel structure sustainable design was manufactured by cored wires and high velocity arc spraying (HVAS) technologies. The developments of thermally sprayed coatings for steel structure protection were described. Based on Al, Zn, Zn-Al and Zn-Al-Mg coatings, the anti-corrosion properties of new-pattern Zn-Al-Mg-RE coating were evaluated through electrochemical methods including electrochemical polarization and electrochemical impedance spectroscopy (EIS) coupled with SEM and XRD. The models of Zn-Al-Mg-RE coating undergoing corrosion with the initial pinhole defect and the latter with accelerated products were also discussed. The results show that Zn-Al-Mg-RE coating exhibites excellent corrosion resistance for long-term immersion, which is helpful for the sustainable design of steel structure in aggressive corrosion conditions. And the corrosion products seem to possess certain self-sealing function.
基金Project supported by the National Natural Science Foundation of China
文摘The relationships between the properties of PVC-MBS polyblend and of the MBS multiphase structure and between the MBS structure and polymerization parameters are studied theoretically and experimentally. MBS resin synthesized from the molecule design principle is suitable to prepare PVC-MBS polyblend with good transparency and high impact strength.
文摘Design for Testability(DFT) is critical in chip design.DFT techniques insert hardware logic to an original design,in order to improve testability of the chip,and thus reduce test cost significantly.In this paper,we introduces the most frequently used DFT techniques,then put emphasis on the DFT policy and the DFT realization of the NDSP25 chip core,and analyses the result at last.
基金Project supported by the National Natural Science Foundation of China(No.91116008)
文摘Truss-core sandwich plates have received much attention in virtue of the high values of strength-to-weight and stiffness-to-weight as well as the great ability of impulseresistance recently. It is necessary to study the stability of sandwich panels under the influence of the thermal load. However, the sandwich plates are such complex threedimensional （3D） systems that direct analytical solutions do not exist, and the finite element method （FEM） cannot represent the relationship between structural parameters and mechanical properties well. In this paper, an equivalent homogeneous continuous plate is ideMized by obtaining the effective bending and transverse shear stiffness based on the characteristics of periodically distributed unit cells. The first order shear deformation theory for plates is used to derive the stability equation. The buckling temperature of a simply supported sandwich plate is given and verified by the FEM. The effect of related parameters on mechanical properties is investigated. The geometric parameters of the unit cell are optimized to attain the maximum buckling temperature. It is shown that the optimized sandwich plate can improve the resistance to thermal buckling significantly.
