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Decadal Changes in Interannual Dependence of the Bay of Bengal Summer Monsoon Onset on ENSO Modulated by the Pacific Decadal Oscillation

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Advances in Atmospheric Sciences 2019年第12期36卷 1404-1416页

作者： xiaofei wu Jiangyu MAO School of Atmospheric Sciences/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province/Joint Laboratory of Climate and Environment Change Chengdu University of Information TechnologyChengdu 610225China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Interannual variations of the Bay of Bengal summer monsoon (BOBSM) onset in association with El Ni-o-Southern Oscillation (ENSO) are reexamined using NCEP1, JRA-55 and ERA20C atmospheric and Hadley sea surface temperature (SST) reanalysis datasets over the period 1900-2017. Decadal changes exist in the dependence of the BOBSM onset on ENSO, varying with the Pacific Decadal Oscillation (PDO). A higher correlation between the BOBSM onset and ENSO arises during the warm PDO epochs, with distinct late (early) onsets following El Ni-o (La Ni-a) events. In contrast, less significant correlations occur during the cold PDO epochs. The mechanism for the PDO modulating the ENSO-BOBSM onset relationship is through the variations in SST anomaly (SSTA) patterns. During the warm PDO epochs, the superimpositions of the PDO-related and ENSO-related SSTAs lead to the SSTA distribution of an El Ni-o (La Ni-a) event exhibiting significant positive (negative) SSTAs over the tropical central-eastern Pacific and Indian Ocean along with negative (positive) SSTAs, especially over the tropical western Pacific (TWP), forming a strong zonal interoceanic SSTA gradient between the TWP and tropical Indian Ocean. Significant anomalous lower tropospheric easterlies (westerlies) together with upper-tropospheric westerlies (easterlies) are thus induced over the BOB, favoring an abnormally late (early) BOBSM onset. During the cold PDO epochs, however, the superimpositions of PDO-related SSTAs with El Ni-o-related (La Ni-a-related) SSTAs lead to insignificant SSTAs over the TWP and a weak zonal SSTA gradient, without distinct circulation anomalies over the BOB favoring early or late BOBSM onsets.

关键词： decadal change Bay of Bengal summer monsoon onset ENSO Pacific Decadal Oscillation

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UP-TreeRec: Building Dynamic User Profiles Tree for News Recommendation

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China Communications 2019年第4期16卷 219-233页

作者： Ming He xiaofei wu Jiuling Zhang Ruihai Dong Beijing University of Technology University College Dublin

Online news recommendation systems aim to address the information explosion of news and make personalized recommendations for users. The key problem of personalized news recommendation is to model users' interests and track their changes. A common way to deal with the user modeling problem is to build user profiles from observed behavior. However, the majority of existing methods make static representations of user profiles and little research has focused on effective user modeling that could dynamically capture user interests in news topics. To address this problem, in this paper, we propose UP-TreeRec, a news recommendation framework based on a user profile tree(UP-Tree), which is a novel framework combining content-based and collaborative filtering techniques. First, by exploiting a novel topic model namely UILDA, we obtain the representation vectors for news content in a topic space as the fundamental bridge to associate user interests with news topics. Next, we design a decision tree with a dynamically changeable structure to construct a user interest profile from the user's feedback. Furthermore, we present a clustering-based multidimensional similarity computation method to select the nearest neighbor of the UP-Tree efficiently. We also provide a Map-Reduce framework-based implemen-tation that enables scaling our solution to real-world news recommendation problems. We conducted several experiments compared to the state-of-the-art approaches on real-world datasets and the experimental results demonstrate that our approach significantly improves accuracy and effectiveness in news recommendation.

关键词： News recommendation user profiling content-based recommendation collaborative filtering

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Understanding and identifying latent data races cross-thread interleaving

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Frontiers of Computer Science 2015年第4期9卷 524-539页

作者： Long ZHEN~ xiaofei LIAO Song wu Xuepeng FAN Hai JIN Services Computing Technology and System Laboratory Cluster and Grid Computing Laboratory School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

Data races are ubiquitous in multi-threaded ap- plications, but they are by no means easy to detect. One of the most important reasons is the complexity of thread in- terleavings. A volume of research has been devoted to the interleaving-insensitive detection. However, all the previous work focuses on the uniform detection （unknown to the char- acteristics of thread interleavings）, thereby making the detec- tion defective in either reporting false positives or suffering from prohibitive overhead. To cope with the problem above, we propose an efficient, precise, and sound step-by-step res- olution based on the characteristics of thread interleavings. We first try to tease apart the categories of thread interleav- ings from the several typical sources arising from the lock synchronizations. We then conduct a brief study and find a new and complex pattern the previous work cannot detect. It is also revealed that the simple pattern with the majority of thread interleavings can be resolved by a simple processing to achieve a big profit for the previous reordering-based design. Our final experimental results demonstrate the effectiveness of our empiricism-based approach, and show that 51.0% of execution time and 52.3 % of trace size arising from the state- of-the-art reordering technique can be saved through a quick filtering of the simple pattern with a negligible （4.45%） per- formance overhead introduced on-the-fly.

关键词： data race happens-before thread interleaving

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Facile Fabrication and Optical Properties of Nanostructural PbSe Films

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Chemical Research in Chinese Universities 2014年第6期30卷 987-990页

作者： LIU Meng QI xiaofei wu Xionggang ZHANG Hengning Xi 'an Modern Chemistry Research Institute Xi 'an 710065 P. R. China

PbSe films with different nanostructures, such as nanoparticles, nanohollows and hierarchical structures, can be synthesized by adjusting the current density and the reaction temperature via a convenient and efficient electrochemical route in the absence of hard template and surfactant. The calculated band gaps of the prepared PbSe nanoparticles and nanohollows were about 0.32 and 0.43 eV, respectively. This suggests that quantum size effect in nanohollows greatly influences their band gap. This preparation method possesses remarkable advantages, such as low cost, high efficiency and easy preparation, which are very suitable for preparing nanomaterials.

关键词： Thin film PbSe Electrodeposition Nanostructural material Optical property

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Structures of a P4-ATPase lipid flippase in lipid bilayers

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Protein & Cell 2020年第6期11卷 458-463页

作者： Yilin He Jinkun Xu xiaofei wu Long Li State Key Laboratory of Membrane Biology Peking-Tsinghua Center for Life SciencesSchool of Life SciencesPeking UniversityBeijing 100871China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China

Dear Editor,Phospholipid molecules are unevenly distributed in membrane bilayers of eukaryotic ***(PE)and phosphatidylserine(PS)are concentrated in the cytoplasmic leaflet,whereas phosphatidylcholine(PC)is enriched in the exoplasmic leaflet(lumenal or extracellular leaflet)(van Meer et al.2008).Type 4 P-type ATPases(P4-ATPases)are the phospholipid flippases which move specific lipids from the exoplasmic leaflet to the cytoplasmic leaflet.P4-ATPases belong to the P-type ATPase family.P4-ATPases are conserved in eukaryotes.

关键词： enriched concentrated Structures

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Potential vorticity analysis of quasi-biweekly rainfall events over the Yangtze Basin in summer 2014

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Atmospheric and Oceanic Science Letters 2021年第6期14卷 20-27页

作者： Chang Tang xiaofei wu Guanshun Zhang Jiangyu Mao School of Atmospheric Sciences/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province/Joint Laboratory of Climate and Environment Change Chengdu University of Information TechnologyChengduChina LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina

A series of heavy rainfall events occurred over the Yangtze River Valley(YRV)in summer 2014,which were modulated by the 10-20-day quasi-biweekly oscillation(QBWO).Thus,the strongest QBWO cycle for the period 10-24 July was used as a representative case to reveal the dynamical mechanism for the QBWO of the YRV rainfall from the potential vorticity(PV)perspective and based on MERRA-2 reanalysis *** quasi-biweekly YRV rainfall was found to depend closely on the QBWO of the upper-tropospheric South Asian high(SAH),with the SAH configuration modified by the southward-intruding midlatitude high PV stream along with southwestward-advected high PV,altering the divergent condition over the *** diagnoses for the anomalous vertical motion demonstrated that,in the wet phase of the QBWO cycle,the upper-tropospheric southward-intruding high PV stream acted as a positive PV advection,while negative PV advection was generated due to the lower-tropospheric southerlies,thereby forming a positive vertical gradient of horizontal PV advection to induce evident isentropic-displacement ascending *** the other hand,the southward-intruding high PV stream extended downward to the middle troposphere,causing the isentropic surfaces to become more sloping,thus producing a strong isentropic-gliding ascending ***,the stronger diabatic heating-related ascending motion was induced to generate positive rainfall anomalies over the *** opposite situation arose in the dry phase,with weak descending motion in magnitude.

关键词： Quasi-biweekly oscillation Summer Yangtze rainfall Potential vorticity Vertical motion

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Synergistic Effect of the Planetary-scale Disturbance, Typhoon and Meso-β-scale Convective Vortex on the Extremely Intense Rainstorm on 20 July 2021 in Zhengzhou

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Advances in Atmospheric Sciences 2023年第3期40卷 428-446页

作者： Guanshun ZHANG Jiangyu MAO Wei HUA xiaofei wu Ruizao SUN Ziyu YAN Yimin LIU Guoxiong wu Guangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction China Meteorological AdministrationGuangzhou 510640China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information TechnologyChengdu 610225China Henan Key Laboratory of Agrometeorological Support and Applied Technique CMAZhengzhou 450003China Henan Meteorological Service Center Zhengzhou 450003China School of Geo-Science and Technology Zhengzhou UniversityZhengzhou 450001China

On 20 July 2021,northern Henan Province in China experienced catastrophic flooding as a result of an extremely intense rainstorm,with a record-breaking hourly rainfall of 201.9 mm during 0800–0900 UTC and daily accumulated rainfall in Zhengzhou City exceeding 600 mm(“Zhengzhou 7.20 rainstorm”for short).The multi-scale dynamical and thermodynamical mechanisms for this rainstorm are investigated based on station-observed and ERA-5 reanalysis *** backward trajectory tracking shows that the warm,moist air from the northwestern Pacific was mainly transported toward Henan Province by confluent southeasterlies on the northern side of a strong typhoon In-Fa(2021),with the convergent southerlies associated with a weaker typhoon Cempaka(2021)concurrently transporting moisture northward from South China Sea,supporting the *** the upper troposphere,two equatorward-intruding potential vorticity(PV)streamers within the planetary-scale wave train were located over northern Henan Province,forming significant divergent flow aloft to induce stronger ascending motion ***,the converged moist air was also blocked by the mountains in western Henan Province and forced to rise so that a deep meso-β-scale convective vortex(MβCV)was induced over the west of Zhengzhou *** PV budget analyses demonstrate that the MβCV development was attributed to the positive feedback between the rainfall-related diabatic heating and high-PV under the strong upward PV advection during the Zhengzhou 7.20 ***,the MβCV was forced by upper-level larger-scale westerlies becoming eastward-sloping,which allowed the mixtures of abundant raindrops and hydrometeors to ascend slantwise and accumulate just over Zhengzhou City,resulting in the record-breaking hourly rainfall locally.

关键词： extreme rainstorm potential vorticity trajectory tracking planetary-scale disturbance meso-β-scale convective system

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Synthesis,gas adsorption and reliable pore size estimation of zeolitic imidazolate framework-7 using CO_2 and water adsorption

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Chinese Journal of Chemical Engineering 2017年第5期25卷 595-601页

作者： Mahdi Niknam Shahrak Morteza Niknam Shahrak Akbar Shahsavand Nasser Khazeni xiaofei wu Shuguang Deng Chemical Engineering Department Faculty of EngineeringQuchan University of Advanced Technology Chemical Engineering Department Faculty of EngineeringFerdowsi University of Mashhad Chemical Engineering Department New Mexico State University Chemical Engineering Department Arizona State University

Reliable estimation of the pore size distribution(PSD) in porous materials such as metal–organic frameworks(MOFs) and zeolitic imidazolate frameworks(ZIFs) is crucial for accurately assessing adsorption capacity and corresponding selectivity. In this study, the so-called zeolitic imidazolate framework-7(ZIF-7) is successfully synthesized via relatively fast and convenient microwave technique. The morphology and structure of the obtained MOF were characterized by XRD, SEM and N_2 and CO_2adsorption/desorption isotherms at 77 K and0 °C respectively. Then, to determine the PSD of the fabricated MOF, carbon dioxide isotherms are experimentally measured at various temperatures up to atmospheric pressure. Afterward, the experimental CO_2 isotherms data are utilized in two recently proposed in-house algorithms of SHN1 and SHN2 to extract the true PSD of manufactured ZIF-7. The obtained results revealed that median pore diameter of the fabricated ZIF-7 is estimated around 0.404 nm and 0.370 nm by using CO_2 isotherms at 273 K and 298 K respectively. These values are in good agreement with the real pore diameter of 0.42 nm. Moreover, experimental data of water adsorption isotherms over four different MOFs, borrowed from literature, are employed to illustrate further effectiveness of the above algorithms on successful determination of the corresponding pore size distributions. All predicted PSDs are proved to be in good agreement with those obtained from independent methods such as topology and morphology studies.

关键词： ZIF-7 Metal–organic framework Size distribution Adsorption CO2 capture Gas

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Activity level of gross α and gross β in airborne aerosol samples around the Qinshan NPP

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Nuclear Science and Techniques 2007年第3期18卷 176-180页

作者： CHEN Bin YE Jida CHEN Qianyuan wu xiaofei SONG Weili WANG Hongfeng Zhejiang Province Environmental Radiation Monitoring Center Hangzhou 310012 China

The monitoring results of gross α and gross β activity from 2001 to 2005 for environmental airborne aero- sol samples around the Qinshan NPP base are presented in this paper. A total of 170 aerosol samples were collected from monitoring sites of Caichenmen village, Qinlian village, Xiajiawan village and Yangliucun village around the Qinshan NPP base. The measured specific activity of gross α and gross β are in the range of 0.02～0.38 mBq/m3 and 0.10～1.81 mBq/m3, respectively, with an average of 0.11 mBq/m3 and 0.45mBq/m3, respectively. They are lower than the average of 0.15 mBq/m3 and 0.52mBq/m3, of reference site at Hangzhou City. It is indicated that the specific activity of gross α and gross β for environmental aerosol samples around the Qinshan NPP base had not been in- creased in normal operating conditions of the NPP.

关键词：环境放射性气溶胶过失误差α 过失误差β

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Magnetic properties and large magnetocaloric effects of GdPd intermetallic compound

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Journal of Rare Earths 2018年第10期36卷 1044-1049页

作者： Jianjun Huo Yusong Du Gang Cheng xiaofei wu Lei Ma Jiang Wang Zhengcai Xia Guanghui Rao School of Materials Science and Engineering Guilin University of Electronic Technology Guilin 541004 China Guangxi Key Laboratory of Information Materials Guilin 541004 China School of Physics Huazhong University of Science and Technology Wuhan 430074 China wuhan National High Magnetic Field Center Huazhong University of Science and Technoogy Wuhan 430074 China

With the intention to explore excellent magnetocaloric materials, the intermetallic compound GdPd was synthesized by arc melting and heat treatment. The microstructure, magnetic and magnetocaloric properties of the intermetallic compound of GdPd were investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and the physical property measurement system（PPMS）. A large reversible magnetocaloric effect is observed in GdPd accompanied by a second order magnetic phase transition from paramagnetism to ferromagnetism at ～39 K. The paramagnetic Curie temperature（θp） and the effective magnetic moment（μ（eff））are determined to be 34.7 K and 8.12 μB/Gd,respectively. The maximum entropy change（｜△SM（Max）｜） and the relative cooling power（RCP） under a field change of 5 T are estimated to be 20.14 J/（kg·K） and 433 J/kg, respectively. The giant reversible magnetocaloric effects（both the large△SM and the high RCP） together with the absence of thermal and field hysteresis make the GdPd compound an attractive candidate for low-temperature magnetic refrigeration.

关键词： CdPd compound Magnetocaloric effect Magnetic entropy change Magnetic refrigeration material Rare earths

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