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797 results on '"Yang, X-H"'

151. Pulsed power capacitor development and outlook

Author

Jow, T. R., primary, MacDougall, F. W., additional, Ennis, J. B., additional, Yang, X. H., additional, Schneider, M. A., additional, Scozzie, C. J., additional, White, J. D., additional, MacDonald, J. R., additional, Schalnat, M. C., additional, Cooper, R. A., additional, and Yen, S. P. S., additional

Published
2015
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158. Research on vibration suppression method of alternating current motor based on fractional order control strategy.

Author

Zhao, H. M., Y. Li, D., Deng, W., and Yang, X. H.

Abstract

At present, the changing structure, material and increasing device are used to suppress the vibration of motor in general. These methods increase system complexity in the different degree. So a novel vibration suppression method based on fractional order Proportional-Integral-Derivative (PID) controller is proposed in this article. First, the digital realization process of fractional order PID controller is illustrated in detail. Then the integer order PID controller and fractional order PID controller are, respectively, used to adjust the input current of inverter to control the 1.5kW alternating current motor. The vibration frequency spectrums and stator current frequency spectrums in low-frequency and carrier frequency band are, respectively, studied by using the comparison and analysis methods. At the same time, the vibration frequency spectrum and stator current frequency spectrum of 15kW alternating current motor are compared and analyzed. And the frequency spectrums near the rotating frequency of stator current of 1.5kW and 15kW alternating current motors are amplified to deeply analyze spectrum characteristics. The experimental results show that the fractional order PID controller has the characteristics of multi-point control by comparing with the integer order PID controller. It changes the frequency components of stator current, and then the electromagnetic torque is more stable. So, the fractional order PID controller can better suppress the vibration of alternating current motor. The proposed method can provide a new idea for vibration suppression of rotating machinery. [ABSTRACT FROM AUTHOR]

Published
2017
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159. Effect of dexmedetomidine on immune function of patients undergoing radical mastectomy: a double blind and placebo control study.

Author

YANG, X.-H., BAI, Q., LV, M.-M., FU, H.-G., DONG, T.-L., and ZHOU, Z.

Abstract

OBJECTIVE: To observe and evaluate the effect of dexmedetomidine on the perioperative immune function of patients undergoing a radical mastectomy. PATIENTS AND METHODS: 124 patients undergoing radical mastectomy were divided into the observation group (treated with dexmedetomidine) and the control group (treated with saline) by randomized digital table and double blinded and randomized design. 10 min before anesthesia induction, the patients in the observation group were injected with dexmedetomidine 0.1 ug.kg-1.min-1. The injection of 0.9% sodium chloride solution was given to the control group at the same rate. In the experiment, the medications of anesthesia induction and anesthesia maintain were identical. Venous blood at five times: T0 (before anesthesia), T1 (6 h after surgery), T2 (24 h after surgery), T3 (48 h after surgery), T4 (72 h after surgery) were collected. ELISA (Enzyme Linked Immunosorbent Assay) was used to detect concentrations of IL-2, IFN-γ, IL-4, IL-6 and IL-10; FACS flow cytometry was used to determine the level of T-lymphocyte subsets (CD3+, CD4+, CD8+) and NK cells. RESULTS: Compared with the control group, the cell levels of CD3+ and CD4+ in the observation group rose remarkably at T3 and T2 (p<0.05). The cell level of CD8+ fell at T2 with significant difference; NK cell level increased noticeably at T1 and T2, and CD4+/CD8+ rose dramatically at all postoperative time points. Obviously, the patients' immune function, to some extent, has been affected; in addition, the concentration of INF-γ in observation group increased prominently at T1, T2 and T3 (p<0.05), and the concentration of IL-2 at T2, IL-10 at T1 and T2, and IL-6 at T2 and T3 in the observation group all rose significantly (p<0.05), and less cytokine Th1 drifted to Th2. CONCLUSIONS: The dexmedetomidine can effectively maintain the homeostasis of cell immune function of patients undergoing a radical mastectomy. [ABSTRACT FROM AUTHOR]

Published
2017

161. Dendronized perylene diimide emitters : Synthesis, luminescence, and electron and energy transfer studies

Author

Qu, J. Q., Zhang, J. Y., Grimsdale, A. C., Mullen, K., Jaiser, Frank, Yang, X. H., and Neher, Dieter (Prof. Dr.)

Subjects
Institut für Physik und Astronomie
Abstract

Aggregation of chromophores in the solid state commonly causes undesirable red shifts in the emission spectra and/or emission quenching. To overcome this problem, we have prepared soluble perylenetetracarboxidiimide dyes in which the chromophores are effectively shielded by polyphenylene dendrimers attached in the bay positions. Models show that attachment of the shielding units in the bay position should provide more efficient shielding than attaching them via the imide moieties. The dendrimers possess excellent film-forming properties due to alkyl substituents on their peripheries. The lack of a red shift in emission upon going from solution to the solid state indicates the dendrons suppress interaction of the emissive cores, leading to pure red-orange emission. Single-layer LEDs produce red-orange emission with relatively low efficiency especially for the higher generation dendrons, which is attributed to poor charge conduction. LEDs using blends of the dendrimers and the undendronized dye as a model compound in PVK have been investigated, and a model to extract relative charge injection rates through the dendritic scaffold from the spectral contributions in the EL spectra is developed

Published
2004

162. Suppression of the keto-emission in polyfluorene light-emitting diodes : Experiments and models

Author

Yang, X. H., Jaiser, F., Dieter Neher, Lawson, Padreyia V., Jean-Luc Brédas, Egbert Zojer, Günther, R., Scanduicci Freitas, P., Forster, M., and Ulrich Scherf

Subjects
Institut für Physik und Astronomie
Abstract

The spectral characteristics of polyfluorene (PF)-based light-emitting diodes (LEDs) containing a defined low concentration of either keto-defects or of the polymer poly(9.9-octylfuorene-co-benzothiadiazole) (F8BT) are preseneted. Both types of blend layers were tested in different device configurations with respect to the relative and absolute intensities of green blue emission components. It is shown that blending hole-transporting molecules into the emission layer at low concentration or incorporation of a suitable hole-transport layer reduces the green emission contribution in the electroluminescence (EL) spectrum of the PF:F8BT blend, which is similar to what is observed for the keto- containing PF layer. We conclude that the keto-defects in PF homopolymer layers mainly constitute weakly emissive electron traps, in agreement with the results of quantum-mechanical calculations

Published
2004

163. Highly efficient single-layer polymer electrophosphorescent devices

Author

Yang, X. H., Neher, Dieter (Prof. Dr.), Hertel, D., and Daubler, T. K.

Subjects
Institut für Physik und Astronomie
Abstract

A commercially available Ir complex has been employed for the preparation of highly efficient (see Figure) single-layer phosphorescent polymer light,emitting diodes by use of appropriate thermal treatment and proper adjustment of the layer composition. These devices exhibit essentially no dependence of the driving field on the concentration of the Ir complex, suggesting that the build-up of space-charge in the layer is insignificant

Published
2004

165. ON THE METALLICITIES OF KEPLER STARS

Author

Dong, Subo, primary, Zheng, Zheng, additional, Zhu, Zhaohuan, additional, De Cat, P., additional, Fu, J. N., additional, Yang, X. H., additional, Zhang, Haotong, additional, Jin, Ge, additional, and Zhang, Yong, additional

Published
2014
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170. Seismic constraints on the radial dependence of the internal rotation profiles of sixKeplersubgiants and young red giants

Author

Deheuvels, S., primary, Doğan, G., additional, Goupil, M. J., additional, Appourchaux, T., additional, Benomar, O., additional, Bruntt, H., additional, Campante, T. L., additional, Casagrande, L., additional, Ceillier, T., additional, Davies, G. R., additional, De Cat, P., additional, Fu, J. N., additional, García, R. A., additional, Lobel, A., additional, Mosser, B., additional, Reese, D. R., additional, Regulo, C., additional, Schou, J., additional, Stahn, T., additional, Thygesen, A. O., additional, Yang, X. H., additional, Chaplin, W. J., additional, Christensen-Dalsgaard, J., additional, Eggenberger, P., additional, Gizon, L., additional, Mathis, S., additional, Molenda-Żakowicz, J., additional, and Pinsonneault, M., additional

Published
2014
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174. Reproductive Biology of Leptocybe invasaFisher & La Salle (Hymenoptera: Eulophidae)

Author

Zheng, X-L, Huang, Z-Y, Li, J, Yang, Z-D, Yang, X-H, and Lu, W

Abstract

Leptocybe invasaFisher & La Salle (Hymenoptera: Eulophidae) is an invasive pest in Eucalyptusplantations around the world. The successful colonization of L. invasais possibly related to its reproductive biology. The objective of this study was to examine the reproductive biology of L. invasa. In Guangxi Province, the sex ratio (proportion of female, 0.99) of L. invasawas female-dominant throughout the year based on natural and artificial infestation. This result was similar to the ratios observed for other geographic populations in China, including those in Fujian (0.99), Guangdong (0.98), Hainan (0.95), Jiangxi (0.96), and Sichuan (0.99). The offspring sex ratio favored females. A large number of females emerged from the galls produced by females, with few males found. Galls on the petioles and midribs of Eucalyptusplants could be caused by newly emerged females with mature eggs. The lengths of the ovariole, spermatheca, common oviduct, and reproductive glands did not differ among L. invasafemales, but their lateral oviducts showed differences from 0 to 42 h after emergence, indicating that this insect is proovigenic. These results could explain why L. invasapopulations can rapidly increase in invaded areas.

Published
2018
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175. LAMOST observations in the Kepler field.

Author

De Cat, P., Fu, J. N., Yang, X. H., Ren, A. B., Frasca, A., Molenda-Żakowicz, J., Catanzaro, G., Gray, R. O., Corbally, C. J., Shi, J. R., Zhang, H. T., and Luo, A. L.

Subjects
STELLAR spectra, TELESCOPES, ASTRONOMICAL observatories, HIGH resolution spectroscopy
Abstract

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) at the Xinglong observatory in China is a new 4-m telescope equipped with 4,000 optical fibers. In 2010, we initiated the LAMOST-Kepler project. We requested to observe the full field-of-view of the nominal Kepler mission with the LAMOST to collect low-resolution spectra for as many objects from the KIC 10 catalogue as possible. So far, 12 of the 14 requested LAMOST fields have been observed resulting in more than 68,000 low-resolution spectra. Our preliminary results show that the stellar parameters derived from the LAMOST spectra are in good agreement with those found in the literature based on high-resolution spectroscopy. The LAMOST data allows to distinguish dwarfs from giants and can provide the projected rotational velocity for very fast rotators. [ABSTRACT FROM AUTHOR]

Published
2015
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176. Simulation of relativistically colliding laser-generated electron flows

Author

Yang, X. H., Dieckmann, Mark Eric, Sarri, Gianluca, Borghesi, Marco, Yang, X. H., Dieckmann, Mark Eric, Sarri, Gianluca, and Borghesi, Marco

Abstract

The plasma dynamics resulting from the simultaneous impact, of two equal, ultra-intense laser pulses, in two spatially separated spots, onto a dense target is studied via particle-in-cell simulations. The simulations show that electrons accelerated to relativistic speeds cross the target and exit at its rear surface. Most energetic electrons are bound to the rear surface by the ambipolar electric field and expand along it. Their current is closed by a return current in the target, and this current configuration generates strong surface magnetic fields. The two electron sheaths collide at the midplane between the laser impact points. The magnetic repulsion between the counter-streaming electron beams separates them along the surface normal direction, before they can thermalize through other beam instabilities. This magnetic repulsion is also the driving mechanism for the beam-Weibel (filamentation) instability, which is thought to be responsible for magnetic field growth close to the internal shocks of gamma-ray burst jets. The relative strength of this repulsion compared to the competing electrostatic interactions, which is evidenced by the simulations, suggests that the filamentation instability can be examined in an experimental setting.

Published
2012
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177. Dynamics of Self-Generated, Large Amplitude Magnetic Fields Following High-Intensity Laser Matter Interaction

Author

Sarri, Gianluca, Macchi, Andrea, Ceccheti, C. A., Kar, S., Liseykina, T.V., Yang, X. H., Dieckmann, Mark Eric, Fuchs, J., Galimberti, M., Gizzi, L. A., Jung, R., Kourakis, Ioannis, Osterholz, J., Pegoraro, Francesco, Robinson, APL, Romagnani, Lorenzo, Willi, Oswald, Borghesi, Marco, Sarri, Gianluca, Macchi, Andrea, Ceccheti, C. A., Kar, S., Liseykina, T.V., Yang, X. H., Dieckmann, Mark Eric, Fuchs, J., Galimberti, M., Gizzi, L. A., Jung, R., Kourakis, Ioannis, Osterholz, J., Pegoraro, Francesco, Robinson, APL, Romagnani, Lorenzo, Willi, Oswald, and Borghesi, Marco

Abstract

The dynamics of magnetic fields with an amplitude of several tens of megagauss, generated at both sides of a solid target irradiated with a high-intensity (∼1019 W/cm2) picosecond laser pulse, has been spatially and temporally resolved using a proton imaging technique. The amplitude of the magnetic fields is sufficiently large to have a constraining effect on the radial expansion of the plasma sheath at the target surfaces. These results, supported by numerical simulations and simple analytical modeling, may have implications for ion acceleration driven by the plasma sheath at the rear side of the target as well as for the laboratory study of self-collimated high-energy plasma jets.

Published
2012
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178. Pulse Power Capacitors

Author

GENERAL ATOMICS ELECTRONIC SYSTEMS INC SAN DIEGO CA, MacDougall, Fred, Jow, Richard, Ennis, Joel, Yen, S. P., Yang, X. H., Ho, Janet, GENERAL ATOMICS ELECTRONIC SYSTEMS INC SAN DIEGO CA, MacDougall, Fred, Jow, Richard, Ennis, Joel, Yen, S. P., Yang, X. H., and Ho, Janet

Abstract

The US Army Research Laboratory has sponsored a capacitor development program for film dielectric capacitors. The program has evaluated dielectric materials for high energy density capacitors from industrial and academic research programs. High performance capacitors have been developed that meet the needs of today's military applications. The performance of recently developed capacitors will be discussed., Presented at the IEEE International Power Modulator Conference, Las Vegas, NV on 27-31 May 2008. Prepared in collaboration with US Army Research Laboratory, Adelphi, MD and the NASA Jet Propulsion Laboratory, Pasadena, CA. The original document contains color images. All DTIC reproductions will be in black and white.

Published
2008

194. Progress on Dust Removal, Denitrification and Desulfurization Technology in Coal-fired Industrial Boiler.

Author

SUN, B. Y., YANG, X. H., LI, M. S., and WU, F. F.

Subjects
COAL combustion, DUST removal, DESULFURIZATION, DENITRIFICATION, COMPARATIVE studies, POLLUTANTS, PREVENTION
Abstract

Pollutants discharge from coal combustion is one of the main causes of smog and haze. Many countries focus on research and development of clean combustion, waste heat utilization and removal of pollutants (e.g. Dust, NOx and SOx) and other key technology and equipment considering the whole process of coal-fired industrial boiler emissions and energy efficiency. In this paper, we make a comparative analysis of domestic and foreign coal-fired industrial boilers ultra-low emissions technology, and points out the research breakthroughs and achievements our country may get in the future. [ABSTRACT FROM AUTHOR]

Published
2016
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196. Preliminary study on diagnosis of lumbar disc degeneration with magnetic resonance T1p, T2 mapping and DWI quantitative detection technologies.

Author

CUI, Y.-Z., YANG, X.-H., LIU, P.-F., WANG, B., and CHEN, W.-J.

Abstract

OBJECTIVE: The value of diagnosing lumbar disc degeneration with T1p magnetic resonance imaging (MRI), T2 mapping and diffusion-weighted imaging (DWI) technologies. PATIENTS AND METHODS: We selected 30 patients diagnosed with lumbar disc herniation (group A), 30 patients with lumbar disc degeneration (group B) and 30 healthy volunteers (group C) and carried out Pfirrmann grading of intervertebral discs (L1-S1 segment) based on conventional T2WI median sagittal images. T1p, T2 mapping and DWI were then applied. RESULTS: Group A primarily had Pfirrmann grades of III-IV, group B had Pfirrmann grades of I-IV and group C had Pfirmann grades of I-II. The differences between the groups were statistically significant (p <0.05). The average T1p, T2 mapping and apparent diffusion coefficient (ADC) values of the nucleus pulposus and annulus fibrosus in group A were significantly lower than in group B. The highest values were in group C, and the differences were statistically significant (p <0.05). CONCLUSIONS: T2WI, T1p MRI, T2 Mapping and DWI technologies have different capacities to diagnose lumbar disc degeneration, and have great value in improving diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Published
2016

198. Asteroseismology of the ZZ Ceti star HS 0507+0434B★

Author

Fu, J.-N., primary, Dolez, N., additional, Vauclair, G., additional, Machado, L. Fox, additional, Kim, S.-L., additional, Li, C., additional, Chen, L., additional, Alvarez, M., additional, Su, J., additional, Charpinet, S., additional, Chevreton, M., additional, Michel, R., additional, Yang, X. H., additional, Li, Y., additional, Zhang, Y. P., additional, Molnar, L., additional, and Plachy, E., additional

Published
2012
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200. Dynamics of Self-Generated, Large Amplitude Magnetic Fields Following High-Intensity Laser Matter Interaction

Author

Sarri, G., primary, Macchi, A., additional, Cecchetti, C. A., additional, Kar, S., additional, Liseykina, T. V., additional, Yang, X. H., additional, Dieckmann, M. E., additional, Fuchs, J., additional, Galimberti, M., additional, Gizzi, L. A., additional, Jung, R., additional, Kourakis, I., additional, Osterholz, J., additional, Pegoraro, F., additional, Robinson, A. P. L., additional, Romagnani, L., additional, Willi, O., additional, and Borghesi, M., additional

Published
2012
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