On the basis of analysis of the present roofbolter’s structures, the pneumatic vane motor roofbolter was proposed and researched. Structure principle of MFT 80Y type pneumatic vane motor roofbolter was expounded, a n...On the basis of analysis of the present roofbolter’s structures, the pneumatic vane motor roofbolter was proposed and researched. Structure principle of MFT 80Y type pneumatic vane motor roofbolter was expounded, a new project of the rotary shearing mechanism with integrating pneumatic vane motor with epicyclic reduction gear unit was carried out, the mathematical model for optimum design of the rotary shearing mechanism was set up, and the optimum design for the rotary shearing mechanism was made by MATLAB Optimization Toolbox. Finally, performance of MFT 80 type pneumatic vane motor roofbolter made with optimum method and the on site experiment were introduced.展开更多
In this work, we derive the nuclear form factor for the spin-independent collision between the WIMPs and nucleus in terms of the relativistic mean field （RMF） theory. Comparison with the traditional form factors whi...In this work, we derive the nuclear form factor for the spin-independent collision between the WIMPs and nucleus in terms of the relativistic mean field （RMF） theory. Comparison with the traditional form factors which are commonly used in literature is given and it is found that our results are slightly above that of the 2PF model by 4% to 8%, but deviate from the Helm form factor by 15% to 25% for the whole recoil energy spectrum of 0 -100 keV. Moreover, taking Xe and Ge as examples, we show the dependence of the form Factor on the recoil energy.展开更多
As a part of boundaries for a free curved surface of a Pelton bucket,the cutout is indispensable to secure the smooth entrance of the unsteady inflow of water jet into the rotating bucket.The cutout of the rotating bu...As a part of boundaries for a free curved surface of a Pelton bucket,the cutout is indispensable to secure the smooth entrance of the unsteady inflow of water jet into the rotating bucket.The cutout of the rotating bucket unsteadily separates a free jet into two branches in both space and time:the impinging branch landing on the relevant bucket surface,and the flow-off branch separated by the cutout toward the preceding bucket.In order to investigate the unsteady jet separation by the cutout three-dimensionally,a semicircular free jet was discretized into 641 nodes of boundary-fitted grids.The position P of impinging jet branch landing on the bucket surface was acquired with the relative velocity W and the water depth D at each node.The trailing edge surface of the flow-off jet branch was simultaneously computed unsteadily.The complicate unsteady interaction of the bucket cutout with the branched free jets was clarified visually with the 3D view of illustrations in order to research the unsteady hydraulic performance of Pelton turbines in space and time.展开更多
文摘On the basis of analysis of the present roofbolter’s structures, the pneumatic vane motor roofbolter was proposed and researched. Structure principle of MFT 80Y type pneumatic vane motor roofbolter was expounded, a new project of the rotary shearing mechanism with integrating pneumatic vane motor with epicyclic reduction gear unit was carried out, the mathematical model for optimum design of the rotary shearing mechanism was set up, and the optimum design for the rotary shearing mechanism was made by MATLAB Optimization Toolbox. Finally, performance of MFT 80 type pneumatic vane motor roofbolter made with optimum method and the on site experiment were introduced.
基金Supported by the National Natural Science Foundation of China under Grant No.11075079
文摘In this work, we derive the nuclear form factor for the spin-independent collision between the WIMPs and nucleus in terms of the relativistic mean field （RMF） theory. Comparison with the traditional form factors which are commonly used in literature is given and it is found that our results are slightly above that of the 2PF model by 4% to 8%, but deviate from the Helm form factor by 15% to 25% for the whole recoil energy spectrum of 0 -100 keV. Moreover, taking Xe and Ge as examples, we show the dependence of the form Factor on the recoil energy.
基金supported by the National Natural Science Foundation of China(Grant No.50379015)the Major Science and Technology Projects in Zhejiang province(Grant No.2008C11057)
文摘As a part of boundaries for a free curved surface of a Pelton bucket,the cutout is indispensable to secure the smooth entrance of the unsteady inflow of water jet into the rotating bucket.The cutout of the rotating bucket unsteadily separates a free jet into two branches in both space and time:the impinging branch landing on the relevant bucket surface,and the flow-off branch separated by the cutout toward the preceding bucket.In order to investigate the unsteady jet separation by the cutout three-dimensionally,a semicircular free jet was discretized into 641 nodes of boundary-fitted grids.The position P of impinging jet branch landing on the bucket surface was acquired with the relative velocity W and the water depth D at each node.The trailing edge surface of the flow-off jet branch was simultaneously computed unsteadily.The complicate unsteady interaction of the bucket cutout with the branched free jets was clarified visually with the 3D view of illustrations in order to research the unsteady hydraulic performance of Pelton turbines in space and time.
