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Search Results: 1 - 10 of 112435 matches for " Xian-Feng Liu "
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Prevalence of and risk factors for aspirin resistance in elderly patients with coronary artery disease
Xian-Feng Liu,Jian Cao,Li Fan,Lin Liu
老年心脏病学杂志(英文版) , 2013,
Abstract: Objective To assess the prevalence of and related risk factors for aspirin resistance in elderly patients with coronary artery disease (CAD). Methods Two hundred and forty-six elderly patients (75.9 ± 7.4 years) with CAD who received daily aspirin therapy (≥ 75 mg) over one month were recruited. The effect of aspirin was assessed using light transmission aggregometry (LTA) and thrombelastography platelet mapping assay (TEG). Aspirin resistance was defined as ≥ 20% arachidonic acid (AA)-induced aggregation and ≥ 70% adenosine diphosphate (ADP)-induced aggregation in the LTA assay. An aspirin semi-responder was defined as meeting one (but not both) of the criteria described above. Based on the results of TEG, aspirin resistance was defined as ≥ 50% aggregation induced by AA. Results As determined by LTA, 23 (9.3%) of the elderly CAD patients were resistant to aspirin therapy; 91 (37.0%) were semi-responders. As determined by TEG, 61 patients (24.8%) were aspirin resistant. Of the 61 patients who were aspirin resistant by TEG, 19 were aspirin resistant according to LTA results. Twenty-four of 91 semi-responders by LTA were aspirin resistant by TEG. Multivariate logistic regression analysis revealed that elevated fasting serum glucose level (Odds ratio: 1.517; 95% CI: 1.176–1.957; P = 0.001) was a significant risk factor for aspirin resistance as determined by TEG. Conclusions A significant number of elderly patients with CAD are resistant to aspirin therapy. Fasting blood glucose level is closely associated with aspirin resistance in elderly CAD patients.
The Extreme Summer Precipitation over East China during 1982–2007 Simulated by the LASG/IAP Regional Climate Model
LIU Jing-Wei,LI Bo,ZHOU Tian-Jun,ZENG Xian-Feng,FENG Lei
大气和海洋科学快报 , 2012,
Hydrothermal Synthesis and Photocatalytic Properties of Cu-doped BiVO4 Microsheets
LIU Guo-Cong, JING Zhen, ZHANG Xi-Bing, LI Xian-Feng, LIU Hong
无机材料学报 , 2013, DOI: 10.3724/sp.j.1077.2013.12204
Abstract: Using Bi(NO3)3·5H2O, NaVO3 and Cu(NO3)2·3H2O as raw materials, Cu-doped BiVO4 microsheets were synthesized by ultrasonic-hydrothermal process with cetyltrimethyl ammonium bromide (CTAB) as template. The as-prepared samples were investigated by XRD, XPS, SEM, HRTEM, UV-Vis and BET tests. The results reveal that uniform and well crystallized Cu/BiVO4 microsheets in monoclinic crystal structure, with length of 1.0–2.0 μm, width of 0.5–2.0 μm and thickness of 200–300 nm, could be obtained via an ultrasonic-hydrothermal route assisted by 2.0 g CTAB. Compared with BiVO4 particles, Cu/BiVO4 nanosheets show a little red shift in the absorption band, resulting in a narrowed band gap (<2.4 eV). For 5.0wt% Cu/ BiVO4 microsheet, its photodegradation rate constant K is5.89 ×10–2 /min and the best photocatalytic activity is found with a 100% degradation of methylene blue (MB) with 10 mg/L concentration under visible-light irradiation for 60 min.
PIC Simulation of a Ka-Band Second Harmonic Gyroklystron Amplifier

Liang Xian-feng,Liu Pu-kun,

电子与信息学报 , 2005,
Abstract: The conditions of the steady operation of the amplifiers are analyzed based on the characteristics of beam-wave interactions of harmonic gyroklystron amplifiers in this paper. The optimized design parameters of the circuit of the beam-wave interactions are obtained by simulation and calculation of the beam-wave interactions of a Ka-band, second harmonic, three cavities gyroklystron amplifier. The results show that this gyroklystron amplifier can produce an output peak power of over 250kW with more than 21dB gain and 23% maximum efficiency at 35GHz with a 70kV, 15A electron beam, and a 3dB bandwidth of about 120 MHz. This work is beneficial to the actual engineering design of the Ka-band second harmonic gyroklystron amplifier.
Energy spectrum and superfluidity of spin-2 ultracold bosons in optical lattices

Wang Yong-Jun,Liu Xian-Feng,Han Jiu-Rong,

中国物理 B , 2009,
Abstract: This paper studies the superfluidity of ultracold spin-2 Bose atoms with weak interactions in optical lattices by calculating the excitation energy spectrum using the Bogoliubov approach. The energy spectra exhibit the characteristics of the superfluid-phase explicitly and it finds the nonvanishing critical speeds of superfluid. The obtained results display that the critical speeds of superfluid are different for five spin components and can be controlled by adjusting the lattice parameters in experiments. Finally it discusses the feasibilities of implementing and measuring superfluid.
Application of data-driven technique to multiple faults diagnosis in grounding grids

LIU Xian-feng,PENG Min-fang,

计算机应用研究 , 2012,
Abstract: This paper introduced designated component analysisDCA to implement multiple faults diagnosis and prediction in grounding grids based on data-driven technique. It established a projection frame, which was the theory foundation for DCA based on multiple faults diagnosis. Under the DCA projection frame, anomaly detection and fault diagnosis problem was transformed into the signifcance detection problem for projection energy of the observation data which was projected to fault subspace spanned by fault patterns defined in advance under condition that the system was abnormal, it could identify faults diagnosis according to the significance detection problem for projection energy. It provided a case study of the diagnosis in grounding grids, and simulation results shows that the efficiency of the DCA method for multiple faults diagnosis.
Synthesis of 2,3-epoxy-1-phenyl-3-aryl-1-propanone by combination of phase transfer catalyst and ultrasound irradiation
Ji-Tai Li,Xian-Feng Liu,,Ying Yin,Chao Du
Organic Communications , 2009,
Abstract: Seven 2,3-epoxy-1-phenyl-3-aryl-1-propanones were synthesized via epoxidation of thecorresponding 1-phenyl-3-aryl-2-propen-1-ones with 30% aqueous hydrogen peroxide in 74-99% yields usingbenzyldimethyltetradecylammonium chloride as phase transfer catalyst under ultrasound irradiation.
Ming-Ming ZHANG,Zhen SHEN,Guo-Qiang LIU,Xian-Feng YI
动物学研究 , 2013, DOI: 10.3724/SP.J.1141.2013.E01E13
Abstract: Althoughdifferencesinfood-hoardingtacticsbothreflectabehavioralresponsetocachepilferageamongrodentspeciesandmayhelpexplaintheircoexistence,differentiationincachepilferingabilitiesamongsympatricrodentswithdifferenthoardingstrategiesisseldomaddressed.Wecarriedoutsemi-naturalenclosureexperimentstoinvestigateseedhoardingtacticsamongthreesympatricrodentspecies(Tamiassibiricus,ApodemuspeninsulaeandClethrionomysrufocanus)andtherelationshipoftheirpilferingabilitiesattheinter-andintraspecificlevels.OurresultsshowedthatT.sibiricusexhibitedarelativelystrongerpilferingabilitythanA.peninsulaeandC.rufocanus,asindicatedbyitshigherrecoveryrateofartificialcaches.MeanwhileA.peninsulaeshowedamediumpilferingabilityandC.rufocanusdisplayedthelowestability.Wealsonotedthatbothcachesizeandcachedepthsignificantlyaffectedcacherecoveryinallthreespecies.T.sibiricusscatter-hoardedmoreseedsthanitlarder-hoarded,A.peninsulaelarder-hoardedmorethanscatter-hoarded,andC.rufocanusactedasapurelarder-hoarder.InT.sibiricus,individualswithlowerpilferingabilitiestendedtoscatterhoardseeds,indicatinganintraspecificvariationinhoardingpropensity.Collectively,theseresultsindicatedthatsympatricrodentspeciesseemtodeploydifferentfoodhoardingtacticsthatallowtheircoexistenceinthetemperateforests,suggestingastrongconnectionbetweenhoardingstrategyandpilferingability.
Xian-Feng Huang
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809038045
Abstract: In the title complex, [Cu(C12H15Cl2N2O)2], the CuII ion is coordinated by one N,O-bidentate and one N,N′,O-tridentate Schiff base ligand, resulting in a distorted CuN3O2 square-based pyramidal coordination for the metal ion, with the O atoms lying trans to each other in the basal plane.
Summer Extreme Temperatures over East China during 1984-2004 Simulated by LASG/IAP Regional Climate Model CREM
ZENG Xian-Feng,LIU Jing-Wei,LI Bo,GUO Zhun,ZHOU Tian-Jun,FENG Lei,
ZENG Xian-Feng
,LIU Jing-Wei,LI Bo,GUO Zhun,ZHOU Tian-Jun,FENG Lei

大气和海洋科学快报 , 2012,
Abstract: The authors examine extreme summer temperatures over East China during 1984-2004 using a regional climate model named CREM (the Climate version of Regional Eta-coordinate Model), which was developed by LASG/IAP. The results show that the main features of the extreme summer temperatures over East China are reproduced well by CREM, and the skill for the minimum temperature is higher than that for the maximum temperature, especially along the Yangtze-Huai River Valley (YHV). The simulated extreme temperatures are lower than those of observation, especially for the maximum temperature. The bias of extreme temperatures is consistent with the cold bias of the climatological mean summer surface air temperature. The skill of the model in simulating the interannual variability of extreme temperatures increases from north to south. The simulated interannual variation of the minimum temperature is more reasonable than the maximum temperature. The underestimation of net solar radiation at the surface leads to a cold bias of the climatological mean temperature. Furthermore, the model underestimates the light and moderate rain, while overestimates heavy rain. It causes the simulated minimum temperature more reasonable than the maximum temperature.
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