Quasiparticles as composite objects in the RVB superconductor

We study the nature of the superconducting state, the origin of d-wave pairing, and elementary excitations of a resonating valence bond (RVB) superconductor. We show that the phase string formulation of the t-J model leads to confinement of bare spinon and holon excitations in the superconducting state, though the vacuum is described by the RVB state. Nodal quasiparticles are obtained as composite excitations of spinon and holon excitations. The d-wave pairing symmetry is shown to arise from short range antiferromagnetic correlations

3D porous Li3V2(PO4)3/hard carbon composites for improving the rate performance of lithium ion batteries

A 3D porous Li3V2(PO4)3/hard carbon composite delivers a capacity of 98 mA h g−1 after 1000 cycles at 10C.</p

Graphene-like carbon sheet/Fe3O4 nanocomposites derived from soda papermaking black liquor for high performance lithium ion batteries

Alkali lignins and its degradation products in the soda papermaking black liquor (SPBL) are renewable resource with the highest natural carbon content. In this work we convert SPBL into the high-performance carbon-based nanocomposite anodes. The unique functional groups of lignin biomass induce spontaneous formation of graphene-like carbon sheet (GCS) in-situ doped SiC/S. The lamellar GCS/FeO nanocomposite (GCS/FO-NC) is facilely prepared via one-step in-situ thermo-chemical method at 700\ua0°C, in which donut shaped FeO nanoparticles with superlattices and inner surface are homogeneously embedded in the interlayer of GCS and are also anchored on its surface. The GCS/FO-NC anode exhibits a ultrahigh first discharge specific capacity of 3829\ua0mAh\ua0g at 50\ua0mA\ua0g in a coin-type Li ion battery, which is more than 4 times the theoretical capacity (924\ua0mAh\ua0g) of FeO and 5 times that of the graphene anode (744\ua0mAh. g). Even at a high current density (1000\ua0mA\ua0g), it still exhibits a high reversible capacity (750\ua0mAh\ua0g) after 1400 discharge/charge cycles. More importantly, the removal efficiency of chemical oxygen demand of SPBL is up to 83.4% during the synthesis process, which reduce its load to environment and synthetic cost of carbon-based nanocomposite anodes

Improved Method of Fatigue Life Assessment for TiAl Alloys

For rapid fatigue life assessment of TiAl alloys, the new method was proposed based on qualitative and quantitative analyses. The qualitative analysis was employed to illustrate the microstructure effect for TiAl alloys on their fatigue life. The new formula is derived for estimation of the interaction forces of dislocations, which yields quite satisfactory results. The results of qualitative and quantitative analyses were used to predict the fatigue life improvement by the addition of trace elements producing grain refinement.Предложен новый метод оценки усталостной долговечности TiAl сплавов по результатам количественного и качественного анализа. С помощью количественного анализа определено влияние микроструктуры TiAl сплавов на их усталостную долговечность. Расчет усилия между дислокациями проведен по стандартной формуле, с помощью которой можно получить точный результат. Количественный и качественный анализ показал, что усталостную долговечность можно повысить путем введения микроэлементов, которые способствуют измельчению зерен.Запропоновано новий метод оцінки довговічності від утомленості ТіАl сплавів за результатами кількісного та якісного аналізу. За допомогою кількісного аналізу визначено вплив мікроструктури TiAl сплавів на їх довговічність від утомленості. Розрахунок зусилля між дислокаціями проведено за стандартною формулою, за допомогою якої можна отримати точний результат. Кількісний та якісний аналіз показав, що довговічність від утомленості можна підвищити шляхом введення мікроелементів, які сприяють подрібненню зерен

Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-

We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi --> D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7 J/Psi events collected with the BESII detector at the BEPC. No excess of signal above background is observed, and 90% confidence level upper limits on the branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi --> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure

Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta

Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector, the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and (7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure

BESII Detector Simulation

A Monte Carlo program based on Geant3 has been developed for BESII detector simulation. The organization of the program is outlined, and the digitization procedure for simulating the response of various sub-detectors is described. Comparisons with data show that the performance of the program is generally satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM

Measurement of branching fractions for the inclusive Cabibbo-favored ~K*0(892) and Cabibbo-suppressed K*0(892) decays of neutral and charged D mesons

The branching fractions for the inclusive Cabibbo-favored ~K*0 and Cabibbo-suppressed K*0 decays of D mesons are measured based on a data sample of 33 pb-1 collected at and around the center-of-mass energy of 3.773 GeV with the BES-II detector at the BEPC collider. The branching fractions for the decays D+(0) -> ~K*0(892)X and D0 -> K*0(892)X are determined to be BF(D0 -> \~K*0X) = (8.7 +/- 4.0 +/- 1.2)%, BF(D+ -> ~K*0X) = (23.2 +/- 4.5 +/- 3.0)% and BF(D0 -> K*0X) = (2.8 +/- 1.2 +/- 0.4)%. An upper limit on the branching fraction at 90% C.L. for the decay D+ -> K*0(892)X is set to be BF(D+ -> K*0X) < 6.6%

Study of J/ψ→ωK+K−J/\psi \to \omega K^+K^-

New data are presented on $J/\psi \to \omega K^+K^-$ from a sample of 58M $J/\psi$ events in the upgraded BES II detector at the BEPC. There is a conspicuous signal for $f_0(1710) \to K^+K^-$ and a peak at higher mass which may be fitted with $f_2(2150) \to K\bar K$. From a combined analysis with $\omega \pi ^+ \pi ^-$ data, the branching ratio $BR(f_0(1710)\to\pi\pi)/BR(f_0(1710) \to K\bar K)$ is $< 0.11$ at the 95% confidence level.Comment: 11 pages, 5 figures. Submitted to Phys. Lett.

Study of J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar

The branching ratios and Angular distributions for J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar are measured using BESII 58 million J/psi.Comment: 11 pages, 5 figure