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Search Results: 1 - 10 of 156328 matches for " Z Li "
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Computer Aided Modeling and Deign of a New Magnetic Sealing Mechanism in Engineering Applications  [PDF]
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.21003
Abstract: This article introduces a new type of magnetic sealing mechanism that reduces the lubrication oil pollution and media gaseous leakage in general reciprocating machinery including air compressors and refrigerators. The feasible function and reliable performance of this new sealing mechanism are introduced and analyzed in this paper. The computer aided design, modeling and analysis are being used to study this new sealing mechanism, and the prototype of this sealing mechanism is being tested. The study indicated the proper function of this sealing mechanism. The major advantages of this sealing mechanism include: improved sealing capacity to prevent the gaseous leakage and oil leakage, simple and compact in structure, lower precision requirement on surfaces of reciprocating pistons and shafts in production and manufacturing, and longer services in sealing life span. Also there is almost no frictional loss during the reciprocating motion of piston or shaft.
Amalgamated-signal Cymometer Based on TMS320F28335  [PDF]
Z. Y. Xu, W. T. Lv, Z. Y. Li
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B232

In our design, an amalgamated-signal cymometer is developed with a TMS320F28335 DSP chip ---- we use its on-chip 12-bit 16-channel AD to conduct a novel dual-sequencer synchronize sampling and averaged to improve the accuracy. Considering the algorithm, we use TI's C28x_FPU_Lib to conduct a FFT with sampled results and correct spectrum with Time-Shift Phase Difference Correcting Spectrum Method based on all-phase spectral analysis. Namely, we design a sampling-frequency self-adaption algorithm which makes operation keep on without outside-hardware command. Actually, the test result shows that our design's frequency resolution ratio is up to 0.4%, and the maximum frequency’s D-value between main and minor signal is up to 29.99 kHz.

Uneventful Spinal Anesthesia in a Patient with Precipitous Drop of Platelet Secondary to HELLP Syndrome: A Case Report and Review of Literatures  [PDF]
Joe Z Liu, Chunhua Li, Hong Wang
Open Journal of Anesthesiology (OJAnes) , 2012, DOI: 10.4236/ojanes.2012.24031
Abstract: Thrombocytopenia caused by Hemolysis, Elevated Liver enzymes and Low Platelet count (HELLP) syndrome in pre-eclampsia parturients can be associated with substantial maternal and neonatal morbidity. Data on the issue of the safety of neuraxial anesthesia with thrombocytopenia in HELLP syndrome is limited. A lower limit of 100,000 per microliter for platelet count was suggested as “safe” for performing neuraxial anesthesia, however there is no supporting data. This lower limit is challenged lately. We present a case of uneventful spinal anesthesia for urgent Cesarean section in a patient with severe pre-eclamsia, HELLP syndrome and precipitous platelet drop from 230,000 to 42,000 per microliter.
Unburned Carbon from Fly Ash for Mercury Adsorption: I. Separation and Characterization of Unburned Carbon  [PDF]
J. Y. Hwang, X. Sun, Z. Li
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2002, DOI: 10.4236/jmmce.2002.11004
Abstract: In searching for a low cost adsorbent for mercury removal from flue gas, this study focuses on the utilization of unburned carbons from fly ash as the substitute material for the costly activated carbons. In this first paper of the series, various separation technologies are introduced for the extraction of unburned carbon from different sources of fly ash. The unburned carbons have been efficiently separated from clean ash, which is a value-added product for the concrete industry, with the separation technologies such as gravity separation, electrostatic separation, and froth flotation. Carbon concentrate with a LOI (Loss On Ignition) value of 67~80% has been generated from the processes. Characterization of the carbon products has been performed to determine the physical and chemical properties of the material. It has been found that the unburned carbon particles had a porous structure, which is similar to the activated carbon. The BET surface area of these materials was in a range of 25~58m2/g. The majority of the pores are in the range of macropore, and some parts of the surface were embedded with glass spheres. There is a linear relationship between the LOI value and the carbon and sulfur content in the carbon concentrate. Chemical analysis indicated that the mercury content in unburned carbon was much higher than the other separation products, which suggests that the carbon has certain ability to capture mercury from flue gas.
Electromagnetic Scattering by a Conducting Cylinder Coated with Metamaterials
C. Li Z. Shen
PIER , 2003, DOI: 10.2528/PIER03012901
Abstract: The electromagnetic scattering from a conducting cylinder coated with metamaterials, which have both negative permittivity and permeability, is derived rigorously by using the classic separation of variables technique. It is found that a conducting cylinder coated with metamaterials has anomalous scattering cross section compared to that coated with conventional dielectric materials. Numerical results are presented and discussed for the scattering cross section of a conducting cylinder coated with metamaterials.
Changes in leaf water status in grapevine graftlings treated with growth regulators
Todi? Slavica,Be?liZ.
Journal of Agricultural Sciences , 2005, DOI: 10.2298/jas0501027t
Abstract: The effect of foliar application of plant growth regulators, paclobutrazol (1000 mg/L), chlorcholine chloride (200 mg/L) and gibberellic acid (100 mg/L) on leaf water status in grapevine graftlings of cv Cardinal was investigated. After stratification and waxing, young vines were planted into vegetation pots and grown in a glasshouse. Foliar treatments were applied once, twice or three times during the vegetative period, starting on 25 July and every 15 days thereafter. Values of total water potential (Tl) and of relative water content (RWC) were measured over the same period. Results indicate a tendency of increased TL values in leaves of plants repeatedly treated with a growth inhibitor paclobutrazol (-1.18 Mpa) compared with untreated (-1.36 Mpa) as well as plants treated twice with gibberellic acid (-1.37 Mpa). RWC in leaves was significantly increased in the second half of the vegetative period when paclobutrazol was applied twice (78%) in comparison with control (75%). Values of both investigated indices point to a more favorable water status of plants treated during the vegetative period with growth inhibitors compared with untreated and plants treated with gibberellic acid.
Kinematics in Randers-Finsler geometry and secular increase of the astronomical unit
X. Li,Z. Chang
Physics , 2009, DOI: 10.1088/1674-1137/35/10/005
Abstract: Kinematics in Finsler space is investigated. It is showed that the result based on the kinematics with a special Finsler structure is in good agreement with the reported value of secular trend in the astronomical unit, $d{\rm AU}/dt=15\pm4[{\rm m/century}]$. The space deformation parameter $\lambda$ in this special structure is very small with scale of $10^{-6}$ and should be a constant. This fact is consistent with the reported value of an anomalous secular eccentricity variation of the Moon's orbit.
Thermally assisted magnetization reversal in the presence of a spin-transfer torque
Z. Li,S. Zhang
Physics , 2003, DOI: 10.1103/PhysRevB.69.134416
Abstract: We propose a generalized stochastic Landau-Lifshitz equation and its corresponding Fokker-Planck equation for the magnetization dynamics in the presence of spin transfer torques. Since the spin transfer torque can pump a magnetic energy into the magnetic system, the equilibrium temperature of the magnetic system is ill-defined. We introduce an effective temperature based on a stationary solution of the Fokker-Planck equation. In the limit of high energy barriers, the law of thermal agitation is derived. We find that the N\'{e}el-Brown relaxation formula remains valid as long as we replace the temperature by an effective one that is linearly dependent of the spin torque. We carry out the numerical integration of the stochastic Landau-Lifshitz equation to support our theory. Our results agree with existing experimental data.
Magnetization dynamics with a spin-transfer torque
Z. Li,S. Zhang
Physics , 2003, DOI: 10.1103/PhysRevB.68.024404
Abstract: The magnetization reversal and dynamics of a spin valve pillar, whose lateral size is 64$\times$64 nm$^2$, are studied by using micromagnetic simulation in the presence of spin transfer torque. Spin torques display both characteristics of magnetic damping (or anti-damping) and of an effective magnetic field. For a steady-state current, both M-I and M-H hysteresis loops show unique features, including multiple jumps, unusual plateaus and precessional states. These states originate from the competition between the energy dissipation due to Gilbert damping and the energy accumulation due to the spin torque supplied by the spin current. The magnetic energy oscillates as a function of time even for a steady-state current. For a pulsed current, the minimum width and amplitude of the spin torque for achieving current-driven magnetization reversal are quantitatively determined. The spin torque also shows very interesting thermal activation that is fundamentally different from an ordinary damping effect.
Light Hadron Physics at the B Factories
Selina Z. Li
Physics , 2008,
Abstract: We report measurements of hadronic final states produced in $e^+e^-$ annihilations from the BaBar and Belle experiments. In particular, we present cross sections measured in several different processes, including two-photon physics, Initial-State Radiation, and exclusive hadron productions at center-of-mass energies near 10.58 GeV. Results are compared with theoretical predictions.
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