J He

Publications (60)43.04 Total impact

• Article: The Contributions of MRI-Based Measures of Gray Matter, White Matter Hyperintensity, and White Matter Integrity to Late-Life Cognition.

  J He, V S S Wong, E Fletcher, P Maillard, D Y Lee, A-M Iosif, B Singh, O Martinez, A E Roach, S N Lockhart, L Beckett, D Mungas, S T Farias, O Carmichael, C Decarli
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  ABSTRACT: GM volume, WMH volume, and FA are each associated with cognition; however, few studies have detected whether these 3 different types of MR imaging measurements exert independent or additive effects on cognitive performance. To detect their extent of contribution to cognitive performance, we explored the independent and additive contributions of GM atrophy, white matter injury, and white matter integrity to cognition in elderly patients. Two hundred and 9 elderly patients participated in the study: 97 were CN adults, 65 had MCI, and 47 had dementia. We measured GM on T1-weighted MR imaging, WMH on FLAIR, and FA on DTI, along with psychometrically matched measures of 4 domains of cognitive performance, including semantic memory, episodic memory, executive function, and spatial abilities. As expected, patients with dementia performed significantly more poorly in all 4 cognitive domains, whereas patients with MCI performed generally less poorly than dementia patients, though considerable overlap in performance was present across groups. GM, FA, and WMH each differed significantly between diagnostic groups and were associated with cognitive measures. In multivariate models that included all 3 MR imaging measures (GM, WMH, and FA), GM volume was the strongest determinant of cognitive performance. These results strongly suggest that MR imaging measures of GM are more closely associated with cognitive function than WM measures across a broad range of cognitive and functional impairment.
  American Journal of Neuroradiology 04/2012; 33(9):1797-803. · 2.93 Impact Factor
• Article: Neural Interaction Characteristics of Monkey&# x2019; s Motor Cortex during Reach-to-grasp Task by Dynamic Bayesian Networks

  D Sang, B Lv, H He, F Wang, J He
  Intelligent Systems, IEEE. 01/2011;
• Article: Combining GMM, Jensen's inequality and BIC for speaker indexing

  Q.-H. He, J.-C. Yang, Y.-X. Li, J. He, X.-Y. Zhang, W. Li
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  ABSTRACT: According to Jensen's inequality, the Bayesian information criterion (BIC) based on the Gaussian mixture model (GMM) is applied to speaker indexing. It can utilise the advantages of BIC and GMM. Experimental results have demonstrated that it is superior to both single-Gaussian-based BIC and GMM for speaker indexing.
  Electronics Letters 05/2010; · 0.96 Impact Factor
• Source

  Available from: nrc.org

  Article: A compact model to predict quantized sub-band energy levels and inversion layer centroids of MOSFETs with a parabolic potential well approximation

  J. He, M. S. Chan, C. Hu, X. Zhang, Y. Y. Wang
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  ABSTRACT: A compact model to predict sub-band energy levels and inversion charge centroids in the MOSFET surface inversion layer has been presented in this paper for parabolic potential well approximation. Based on a coupled solution of the Schrödinger equation and the Poisson equation following the WKB method, one transcendental equation of the sub-band energy level has been rigorously derived and then the approximate analytical solutions for the sub-band energy levels and the inversion charge centroids have been obtained. The analytical results are compared with the numerical data and a good agreement between the analytical and numerical is found.
  Molecular Simulation 10/2005; 31(12):845-850. · 1.33 Impact Factor
• Article: Evidence of ψ(3770) non-DD¯ decay to J/ψπ+π-

  BES Collaboration, J. Z. Bai, Y. Ban, J. G. Bian, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, J. Chen, J. C. Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: Evidence of ψ(3770) decays to a non-DD¯ final state is observed. A total of 11.8±4.8±1.3ψ(3770)→J/ψπ+π- events are obtained from a data sample of 27.7 pb-1 taken at center-of-mass energies around 3.773 GeV using the BES-II detector at the BEPC. The branching fraction is determined to be BF(ψ(3770)→J/ψπ+π-)=(0.34±0.14±0.09)%, corresponding to the partial width of Γ(ψ(3770)→J/ψπ+π-)=(80±33±23) keV.
  Physics Letters B 12/2004; 605:63-71. · 3.95 Impact Factor
• Article: ψ(2S) decays into J/ψ plus two photons

  J. Z. Bai, Y. Ban, J. G. Bian, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, H. X. Chen, J. Chen, J. C. Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: Using γγJ/ψ,J/ψ⃗e+e- and μ+μ- events from a sample of 14.0×106 ψ(2S) decays collected with the BESII detector, the branching fractions for ψ(2S)→π0J/ψ, ηJ/ψ, and ψ(2S)→γχc1,γχc2→γγJ/ψ are measured to be B[ψ(2S)→π0J/ψ]=(1.43±0.14±0.12)×10-3, B[ψ(2S)→ηJ/ψ]=(2.98±0.09±0.23)%, B[ψ(2S)→γχc1→γγJ/ψ]=(2.81±0.05±0.23)%, and B[ψ(2S)→γχc2→γγJ/ψ]=(1.62±0.04±0.12)%.
  Phys. Rev. D. 07/2004; 70(1).
• Article: Search for the pentaquark state in ψ(2S) and J/ψ decays to K0SpK-n¯ and K0Sp¯K+n

  J. Z. Bai, Y. Ban, J. G. Bian, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, H. X. Chen, J. Chen, J. C. Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: Results are presented on ψ(2S) and J/ψ hadronic decays to K0SpK-n¯ and K0Sp¯K+n final states from data samples of 14 million ψ(2S) and 58 million J/ψ events accumulated at the BES II detector. No Θ(1540) signal, the pentaquark candidate, is observed, and upper limits are set for B(ψ(2S)→ΘΘ¯→K0SpK-n¯+K0Sp¯K+n)<0.84×10-5 and B(J/ψ→ΘΘ¯→K0SpK-n¯+K0Sp¯K+n)<1.1×10-5 at the 90% confidence level. For single Θ(1540) production, the upper limits determined by our analysis are also on the order of 10-5 in both ψ(2S) and J/ψ decays.
  Physical review D: Particles and fields 06/2004; 70(1):12004.
• Article: Determination of B(χcJ→pp̅ ) in ψ(2S) decays

  J. Z. Bai, Y. Ban, J. G. Bian, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, H. X. Chen, J. Chen, J. C. Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: The processes ψ(2S)→γχcJ, χcJ→pp̅ (J=0,1,2) are studied using a sample of 14×106 ψ(2S) decays collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider. Very clear χc0, χc1 and χc2 signals are observed, and the branching fractions B(χcJ→pp̅ ) (J=0,1,2) are determined to be (27.1-3.9+4.3±4.7)×10-5, (5.7-1.5+1.7±0.9)×10-5, and (6.5-2.1+2.4±1.0)×10-5, respectively, where the first errors are statistical and the second are systematic.
  Phys. Rev. D. 05/2004; 69(9).
• Article: Measurements of ψ(2S) decays into vector-tensor final states

  J. Z. Bai, Y. Ban, J. G. Bian, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, H. X. Chen, J. Chen, J. C. Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: Decays of the ψ(2S) into vector plus tensor meson final states have been studied with 14 million ψ(2S) events collected with the BESII detector. The branching fractions of ψ(2S)→ωf2(1270), ρa2(1320), K*(892)0K2*(1430)0+c.c., and φf2′(1525) are determined. They improve upon previous BESI results and confirm the violation of the “12%” rule for ψ(2S) decays to VT channels with higher precision.
  Phys. Rev. D. 04/2004; 69(7).
• Article: Observation of the decay psi(2S)-->K0SK0L.

  J Z Bai, Y Ban, J G Bian, X Cai, J F Chang, H F Chen, H S Chen, H X Chen, J Chen, J C Chen, [......], L Zhou, N F Zhou, K J Zhu, Q M Zhu, Yingchun Zhu, Y C Zhu, Y S Zhu, Z A Zhu, B A Zhuang, B. S. Zou
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  ABSTRACT: The decay psi(2S)-->K(0)(S)K(0)(L) is observed using psi(2S) data collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider; the branching fraction is determined to be B(psi(2S)-->K(0)(S)K(0)(L))=(5.24+/-0.47+/-0.48)x10(-5). Compared with J/psi-->K(0)(S)K(0)(L), the psi(2S) branching fraction is enhanced relative to the prediction of the perturbative QCD "12%" rule. The result, together with the branching fractions of psi(2S) decays to other pseudoscalar meson pairs (pi(+)pi(-) and K+K-), is used to investigate the relative phase between the three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.
  Physical Review Letters 02/2004; 92(5):052001. · 7.37 Impact Factor
• Article: Improved measurement of the branching ratio of J/ψ⃗KS0KL0

  J. Z. Bai, Y. Ban, J. G. Bian, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, H. X. Chen, J. Chen, J. C. Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: The branching ratio of J/ψ⃗KS0KL0 is measured with improved precision to be B(J/ψ⃗KS0KL0)=(1.82±0.04±0.13)×10-4 using J/ψ data collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Positron Collider. This result is used to test the perturbative QCD prediction between ψ(2S) and J/ψ decays and to investigate the relative phase between the three-gluon and one-photon annihilation amplitudes in J/ψ decays.
  Phys. Rev. D. 01/2004; 69(1).
• Article: Improved measurement of the branching ratio of J/ψ→K0SK0L

  J. Z. Bai, Y. Ban, J. G. Bian, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, H. X. Chen, J. Chen, J. C. Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: The branching ratio of J/ψ→K0SK0L is measured with improved precision to be B(J/ψ→K0SK0L)=(1.82±0.04±0.13)×10-4 using J/ψ data collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Positron Collider. This result is used to test the perturbative QCD prediction between ψ(2S) and J/ψ decays and to investigate the relative phase between the three-gluon and one-photon annihilation amplitudes in J/ψ decays.
  Physical review D: Particles and fields 12/2003; 69(1):12003.
• Article: Giant magnetoresistance in Mn2−xCuxSb (x⩽0.4) compounds

  Y. Q. Zhang, Z. D. Zhang, D. K. Xiong, W. F. Li, J. He
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  ABSTRACT: Magnetic and magnetotransport properties of Mn2−xCuxSb (x=0, 0.1, 0.2, and 0.4) compounds have been studied. A phase transition from a ferrimagnetic to an antiferromagnetic state occurs in the Cu-substituted compounds as the temperature is reduced. A magnetic field-driven transition takes place in the Cu-containing compounds, changing the spin configuration from antiferromagnetic to ferromagnetic. The giant magnetoresistance effect is observed in these compounds, accompanying the transition. The largest magnetoresistance ratio of −40% is observed for Mn1.9Cu0.1Sb at 170 K in a magnetic field of 5 T. © 2003 American Institute of Physics.
  Journal of Applied Physics. 09/2003; 94(7):4726-4728.
• Article: Partial wave analyses of J/ψ⃗γK+K- and γKS0KS0

  J. Z. Bai, Y. Ban, J. G. Bian, D. V. Bugg, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, H. X. Chen, Jie Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: Results are presented on J/ψ radiative decays to K+K- and KS0KS0 based on a sample of 58M J/ψ events taken with the BES II detector. A partial wave analysis is carried out using the relativistic covariant tensor amplitude method in the 1–2 GeV mass range. There is conspicuous production due to the f2′(1525) and f0(1710). The latter peaks at a mass of 1740±4-25+10MeV with a width of 166-8-10+5+15MeV. Spin 0 is strongly preferred over spin 2. For the f2′(1525), the helicity amplitude ratios are determined to be x2=1.00±0.28-0.36+1.06 and y2=0.44±0.08-0.56+0.10.
  Phys. Rev. D. 09/2003; 68(5).
• Article: Observation of a near-threshold enhancement in the pp mass spectrum from radiative J/psi-->gammapp decays.

  J Z Bai, Y Ban, J G Bian, X Cai, J F Chang, H F Chen, H S Chen, J Chen, Jie Chen, J C Chen, [......], L Zhou, N F Zhou, K J Zhu, Q M Zhu, Yingchun Zhu, Y C Zhu, Y S Zhu, Z A Zhu, B A Zhuang, B S Zou
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  ABSTRACT: We observe a narrow enhancement near 2m(p) in the invariant mass spectrum of pp pairs from radiative J/psi-->gammapp decays. No similar structure is seen in J/psi-->pi(0)pp decays. The results are based on an analysis of a 58 x 10(6) event sample of J/psi decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit-Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m(p) at M=1859(+3)(-10) (stat)+5-25(syst) MeV/c(2) and the total width is Gamma<30 MeV/c(2) at the 90% confidence level. These mass and width values are not consistent with the properties of any known particle.
  Physical Review Letters 07/2003; 91(2):022001. · 7.37 Impact Factor
• Article: First evidence of ΛΛ̅ in χcJ decays

  J. Z. Bai, Y. Ban, J. G. Bian, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, J. Chen, J. C. Chen, Y. B. Chen, [......], L. Zhou, N. F. Zhou, K. J. Zhu, Q. M. Zhu, Yingchun Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: The first observation of χcJ(J=0,1,2) decays to ΛΛ̅ is reported using ψ(2S) data collected with the Beijing Spectrometer detector at the Beijing Electron Positron Collider. The branching ratios are determined to be B(χc0→ΛΛ̅ )=(4.7-1.2+1.3±1.0)×10-4, B(χc1→ΛΛ̅ )=(2.6-0.9+1.0±0.6)×10-4 and B(χc2→ΛΛ̅ )=(3.3-1.3+1.5±0.7)×10-4. The results are compared with model predictions.
  Phys. Rev. D. 06/2003; 67(11).
• Article: ψ(2S) two- and three-body hadronic decays

  J. Z. Bai, Y. Ban, J. G. Bian, I. Blum, X. Cai, J. F. Chang, H. F. Chen, H. S. Chen, J. Chen, Jie Chen, [......], B. Q. Zhou, G. M. Zhou, L. Zhou, K. J. Zhu, Q. M. Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, B. S. Zou
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  ABSTRACT: We report measurements of branching fractions for ψ(2S) decays into ωπ+π-, b1π, ωf2(1270), ωK+K-, ωpp̅ , φπ+π-, φf0(980), φK+K-, and an upper limit for φpp̅ final states based on a data sample of (4.02±0.22)×106ψ(2S) events collected with the BESI detector at the Beijing Electron-Positron Collider. The branching fractions for b1π and ωf2(1270) update previous BES results, while those for other decay modes are first measurements. The ratios of ψ(2S) and J/ψ branching fractions are smaller than what is expected from the 12% rule by a factor of 5 for ωf2(1270) and by a factor of 2 for ωπ+π-, ωpp̅ , and φK+K-, while for other studied channels the ratios are consistent with expectations within errors.
  Phys. Rev. D. 03/2003; 67(5).
• Article: Effects of germanium on the electronic transport mechanism in Co20(Cu1-xGex)80 nanogranular ribbons

  J. He, Z. D. Zhang, J. P. Liu, D. J. Sellmyer
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  ABSTRACT: The dependency of giant magnetoresistance (GMR) on the nonmagnetic matrix in nanogranular Co20(Cu1-xGex)80 ribbons was studied. When the matrix Cu is substituted with semiconductor Ge, the magnetoresistance transitioned from negative to positive at low temperatures. The positive GMR effect is closely related to the quantity of Co/Co3Ge2/Co junctionlike configurations. This result provides evidence for the competition between two types of electronic transport mechanisms in the magnetic granular ribbons: (i) electronic spin-dependent scattering, inducing a negative magnetoresistance and (ii) Coulomb blockade of the electronic tunneling, inducing a positive magnetoresistance.
  Journal of Materials Research. 11/2002; 17(12):3050 - 3055.
• Source

  Available from: ac.cn

  Article: Transition from negative magnetoresistance behavior to positive behavior in Co20(Cu1-xGex)80 ribbons

  J. He, Z. D. Zhang, J. P. Liu, D. J. Sellmyer
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  ABSTRACT: We report a transition of the giant magnetoresistance (GMR) behavior in nanocrystalline Co ₂₀( Cu _1-x Ge _x)₈₀ ribbons from negative to positive, as the semiconductor Ge substitutes for the Cu matrix. The growth of the hexagonal Co ₃ Ge ₂ compound leads to a change of the physical origin of the GMR. The normal spin-dependent transport behavior in the CoCu granular system evolves into Coulomb blockade behavior of electronic tunneling in ribbons with a Co / Co ₃ Ge ₂/ Co junctionlike configuration. © 2002 American Institute of Physics.
  Applied Physics Letters 04/2002; · 3.84 Impact Factor
• Source

  Available from: Jian Guo Bian

  Article: Measurements of the cross section for e(+)e(-) --> hadrons at center-of-mass energies from 2 to 5 GeV.

  J Z Bai, Y Ban, J G Bian, A D Chen, H F Chen, H S Chen, J C Chen, X D Chen, Y B Chen, B S Cheng, [......], B Q Zhou, G M Zhou, L Zhou, K J Zhu, Q M Zhu, Y C Zhu, Y S Zhu, Z A Zhu, B A Zhuang, B S Zou
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  ABSTRACT: We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.
  Physical Review Letters 03/2002; 88(10):101802. · 7.37 Impact Factor