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R&D Status of High-current Accelerators at IFP
J. J. Deng,J. S. Shi,W. P. Xie,L. W. Zhang,K. Z. Zhang,S. P. Feng,J. Li,M. Wang,Y. He,L. S. Xia,Z. Y. Dai,H. T. Li,L. Wen,S. F. Chen,X. Li,Q. G. Lai,M. H. Xia,Y. C. Guan,S. Y. Song,L. Chen 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61
High-current accelerators have many important applications in Z-pinches, high-power microwaves, and free electron lasers, imploding liners and radiography and so on. Research activities on Zpinches, imploding liners, radiography at the Institute of Fluid Physics (IFP) are introduced. Several main high-current accelerators developed and being developed at IFP are described, such as the Linear Induction Accelerator X-Ray Facility Upgrade (LIAXFU, 12 MeV, 2.5 kA, 90 ns), the Dragon-I linear induction accelerator (20 MeV, 2.5 kA, 60 ns), and the Primary Test Stand for Z-pinch (PTS, 10 MA, 120 ns). The design of Dragon-II linear induction accelerator (20 MeV, 2.5 kA, 3 × 60 ns) to be built will be presented briefly.
문학수,강화석 한국농업기계학회 2003 바이오시스템공학 Vol.28 No.1
An oscillating digger mechanism was designed, constructed, and tested. The mechanism is consisted of a six-bar linkage, one four-bar linkage was for the digger blade and the other one for variable soil-crop separation.Experimental variables were amplitude(3,6,9 mm), frequency(11.2,14.9,17.0 Hz), and forward speed of tactor(0.91, 1.13, 1.56 km/h).Each combination of these variables was replicated three times to measure the draft and troque for power requirement evaluation, and the broken-up soil height on the soil separation sieve mechanism, Four parameters λ(the ratio of vibration speed to forward velocity), p(the ratio of vibration acceleration to forward velocity), K(the ratio of vibration acceleration to gravitational acceleration), and T(the product of λ and K)were induced from three experimental variables: amplitude, frequency, and tractor speed. And the power requirement and soil separation ability were analyzed by regression. Though λ and K were known to be the representative parameters, T was the Most moderate one to explain draft, torque, and soil separation in this study. It was estimated that the T equal to or greater than 2.4 was the minimum recommended value. Figure 18 would be useful for the selection of amplitude, frequency, or operating tractor speed, once any two variables are known.
Z.X. Wen,J.P. Wang,Y.W. Wu,K.J. Zhou,Z.F. Yue 한국물리학회 2018 Current Applied Physics Vol.18 No.6
Material deformation caused by the interaction between defects is a significant factor of material fracture failure. The present study employs molecular dynamics simulations of single-void and double-void crystalline Ni atomic systems to investigate inter-void interactions. Furthermore, simulations showing the evolution of dislocations for three different crystallographic orientations are conducted to study the void growth and coalescence. The simulations also consider the effect of the radius of the secondary void on dislocation evolution. The results show that double-void systems are more prone to yield than single-void systems. Further microstructural analysis indicates that the interaction between voids is realized by dislocation reactions. The simulation results of the dislocation evolution of the three orientations reveal that a relationship exists between the evolution of the dislocation density and the stress-strain curve. At the initial stage of dislocation, the dislocation grows slowly, and consists of Shockley partial dislocation. The dislocation growth rate then increases significantly in the sharply declining stage of the stress-strain curve, where most of dislocations are Shockley partial dislocation. Analysis of the dislocation length during the overall simulation indicates that the dislocation length of the [110] orientation is the longest, followed by that of the [111] orientation and the [100] orientation, which has the shortest dislocation length.
X.Z. Yang,L. Wen 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.4
In this paper, we employ a novel method of field activated and pressure assisted synthesis to prepare ultra-hard, superabrasives from the elemental constituents (aluminum, magnesium and boron). Under the conditions in the present work, the simultaneous synthesis and consolidation of such intermetallic compounds can be achieved at 1500 o C with a pressure of 60 MPa. The prepared compounds show a hardness of 32.5 GPa, which is consistent with the hardness of AlMgB14 prepared by hot uniaxial pressing, and the average density was 2.62 g/cm3 . Furthermore, it is found that such compounds are not produced from the elemental constituents in the present condition.
Wind-induced responses and dynamic characteristics of a super-tall building under a typhoon event
X. G. Hua,K. Xu,Y.W. Wang,Q. Wen,Z. Q. Chen 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.1
Wind measurements were made on the Canton Tower at a height of 461 m above ground during the Typhoon <i>Vincente</i>, the wind-induced accelerations and displacements of the tower were recorded as well. Comparisons of measured wind parameters at upper level of atmospheric boundary layer with those adopted in wind tunnel testing were presented. The measured turbulence intensity can be smaller than the design value, indicating that the wind tunnel testing may underestimate the crosswind structural responses for certain lock-in velocity range of vortex shedding. Analyses of peak factors and power spectral density for acceleration response shows that the crosswind responses are a combination of gust-induced buffeting and vortex-induced vibrations in the certain range of wind directions. The identified modal frequencies and mode shapes from acceleration data are found to be in good agreement with existing experimental results and the prediction from the finite element model. The damping ratios increase with amplitude of vibration or equivalently wind velocity which may be attributed to aerodynamic damping. In addition, the natural frequencies determined from the measured displacement are very close to those determined from the acceleration data for the first two modes. Finally, the relation between displacement responses and wind speed/direction was investigated.
Cui, H.Z.,Wen, J.F.,Choi, H.R.,Li, X.,Cho, K.W.,Kang, D.G.,Lee, H.S. North-Holland ; Elsevier Science Ltd 2011 european journal of pharmacology Vol.653 No.1
Ursolic acid is reported to have beneficial effects on the regulation of cardiovascular homeostasis. However, the effects of ursolic acid on cardiac hormone secretion are yet to be defined. The present study was designed to test the effects of ursolic acid on the secretory and contractile functions of the atria. Experiments were conducted in isolated perfused beating rabbit atria. We measured the changes in atrial dynamics, pulse pressure, stroke volume, cAMP efflux, as well as the secretion of atrial natriuretic peptide (ANP). Ursolic acid increased ANP secretion and mechanical dynamics in a concentration-dependent manner. The inhibition of L-type Ca<SUP>2+</SUP> channels with nifedipine attenuated the ursolic acid-induced increase in ANP secretion but not mechanical dynamics. The inhibition of K<SUP>+</SUP><SUB>ATP</SUB> channels with glibenclamide attenuated the ursolic acid-induced increase in ANP secretion-but not atrial dynamics-in a concentration-dependent manner. The selective Na<SUP>+</SUP>-K<SUP>+</SUP>-ATPase inhibitor ouabain blocked the ursolic acid-induced increase in atrial dynamics but not ANP secretion. These findings show that ursolic acid increases ANP secretion via its activation of K<SUP>+</SUP><SUB>ATP</SUB> channels and subsequent inhibition of Ca<SUP>2+</SUP> entry through L-type Ca<SUP>2+</SUP> channels in rabbit atria. These data also suggest that ursolic acid increases atrial dynamics via its inhibition of Na<SUP>+</SUP>-K<SUP>+</SUP>-ATPase activity.
J. J. Wang,Z. X. Wen,Y. M. Zhang,Y. Q. Yang,H. Q. Pei,Z. F. Yue 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11
Using a combination of tests and numerical simulations, the fatigue behaviors of a Ni-based single crystal (SC) alloy withdifferent surface roughnesses (SRs) are studied. The test results demonstrate that the fatigue life decreases with increasingSR, while the strain accumulation shown an opposite trend. Surface defects can give rise to the nucleation, aggregationand growth of surface cracks, which are the principal inducement of fatigue failure. Finite element models of the actualsurface topography were established, and the notched plate models whose modelling parameters were determined by theSR parameters ( Rz , Rsm , Ra ) were used to equivalently simplify, the equivalent errors are within 5%. In addition, a semiempiricalformula between the surface stress concentration factor ( Kt ) and the SR parameters was fitted. By introducing theKt expressed by the SR parameters into a fatigue damage model based on crystal plasticity theory, a fatigue life predictionmethod of a Ni-based SC alloy that considers SR was established, and it has been verified to exhibit excellent consistencywith the test results.