990 research outputs found
Recent Results from BESII
The studies on the multi-quark candidates, light scalar mesons and excited
baryon states at BES are presented, based on data
collected with BESII detector. The measurements of some and
decays are presented too. We also report the searches for the lepton flavor
violation and pentaquark states in decays.Comment: Talk given at 10th International Symposium on Meson-Nucleon Physics
and the Structure of the Nucleon (MENU 2004), Beijing, China, 29 Aug - 4
Sept. 2004, 6 pages, 8 figures, to be published in Int. J. Mod. Phy
Recent Results from BES
We report partial wave analysis results for based
on BESI events, and find to be dominant in
the mass region. Some very preliminary results are presented from
the events newly collected at the upgraded
BES(BESII). Using the world largest data sample, BES measures
branching ratios of radiative and hadronic decays. The preliminary R
values measured by BESII in the 2-5 GeV energy region are also presented.Comment: 11 pages, 11 figures, proceeding paper for IV International
Conference on Hyperons, Charm and Beauty Hadrons, June of 2000, Valencia,
Spai
Using MicroPET Imaging in Quantitative Verification of Acupuncture Effect in Ischemia Stroke Treatment
While acupuncture has survived several thousand years’ evolution of medical practice, its function still remains as a myth from the view point of modern medicine. Our goal in this paper is to quantitatively understand the function of acupuncture in ischemia stroke treatment. We carried out a comparative study using the Sprague Dawley rat animal model. We induced the focal cerebral ischemia in the rats using the middle cerebral artery occlusion (MCAO) procedure. For each rat from the real acupuncture group (n = 40), sham acupoint treatment group (n = 54), and blank control group (n = 16), we acquired 3-D FDG-microPET images at baseline, after MCAO, and after treatment (i.e., real acupuncture, sham acupoint treatment, or resting according to the group assignment), respectively. After verifying that the injured area is in the right hemisphere of the cerebral cortex in the brain by using magnetic resonance imaging(MRI) and triphenyl tetrazolium cchloride (TTC)-staining, we directly compared the glucose metabolism in the right hemisphere of each rat. We carried out t-test and permutation test on the image data. Both tests demonstrated that acupuncture had a more positive effect than non-acupoint stimulus and blank control (P < 0.025) in increasing the glucose metabolic level in the stroke-injured area in the brain, while there was no statistically significant difference between non-acupoint stimulus and blank control (P>0.15). The immediate positive effect of acupuncture over sham acupoint treatment and blank control is verified using our experiments. The long-term benefit of acupuncture needs to be further studied
Manipulation of magnetic topological textures via perpendicular strain and polarization in van der Waals magnetoelectric heterostructure
Multi-functional manipulation of magnetic topological textures such as
skyrmions and bimerons in energy-efficient ways is of great importance for
spintronic applications, but still being a big challenge. Here, by
first-principles calculations and atomistic simulations, the creation and
annihilation of skyrmions/bimerons, as key operations for the reading and
writing of information in spintronic devices, are achieved in van der Waals
magnetoelectric CrISe/In2Se3 heterostructure via perpendicular strain or
electric field without external magnetic field. Besides, the bimeron-skyrmion
conversion, size modulation and the reversible magnetization switching from
in-plane to out-of-plane could also be realized in magnetic-field-free ways.
Moreover, the topological charge and morphology can be precisely controlled by
a small magnetic field. The strong Dzyaloshinskii-Moriya interaction and
tunable magnetic anisotropy energy in a wide window are found to play vital
roles in such energy efficient multi-functional manipulation, and the
underlying physical mechanisms are elucidated. Our work predicts the
CrISe/In2Se3 heterostructure being an ideal platform to address this challenge
in spintronic applications, and theoretically guides the low-dissipation
multi-functional manipulation of magnetic topological textures.Comment: 7 pages, 5 figure
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Energy transfer in multi-collision environments; an experimental test of theory: LiH (10;2) in H2(0;0)
We report separate experimental and theoretical studies that follow the equilibration of highly excited LiH (v=10;J=2) in H2 at 680K. Experiments that follow the time evolution of state-tostate population transfer in multi-collision conditions were carried out by Shen and co-workers at Xinjiang University and East China Institute of Science and Technology with µs resolution. At the same time, theoretical computations on the relaxation of this gas mixture were undertaken by McCaffery and co-workers at Sussex University. Rapid, near-resonant, vibration-vibration energy exchange is a marked feature of the initial relaxation process. However, at later stages of ensemble evolution, slower vibration-rotation transfer processes form the dominant relaxation mechanism. The physics of the decay process are complex and, as demonstrated experimentally here, a single exponential expression is unlikely to capture the form of this decay with any accuracy. When these separate studies were complete, the evolution of modal temperatures from the Sussex calculations were compared with experimental measurements of these same quantities from Shanghai and Urumqui. The two sets of data were found to be identical to within experimental and computational error. This constitutes an important experimental validation of the theoretical/computational model developed by the Sussex group and a significant experimental advance by the group of Shen et.al
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