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Discovery of a high confidence soft lag from an X-ray flare of Markarian 421

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 224-227页

作者： ZHANG YouHong1,HOU ZhengTian2,SHAO Li3 & ZHANG Peng1 1 department of physics and tsinghua center for astrophysics(THCA),tsinghua university,beijing 100084,china 2 Group of Mathematics and physics,Shangqiu Medical College,Shangqiu 476100,china 3 Max-Planck-Institut für extraterrestrische Physik,Postfach 1312,Garching 85741,Germany department of physics and tsinghua center for astrophysics (THCA) Tsinghua University Beijing China Group of Mathematics and physics Shangqiu Medical College Shangqiu China Max-Planck-Institut für extraterrestrische Physik Garching Germany

We present the X-ray variability properties of the X-ray and TeV bright blazar Mrk 421 with a-60 ks long XMM-Newton observation performed on November 9-10,*** source experienced a pronounced flare,of which the inter-band time lags were determined with a very high confidence *** soft(0.6-0.8 keV) X-ray variations lagged the hard(4-10 keV) ones by 1.09+0.11-0.12 ks,and the soft lag increases with increasing difference in the photon *** energy-dependent soft lags can be well fitted with the difference of the energy-dependent cooling timescales of the relativistic electron distribution responsible for the observed X-ray emission,which constrains the magnetic field strength and Doppler factor of the emitting region to be Bδ 1/3-1.78 Gauss.

关键词： BL Lacertae objects:individual:Mrk-421 galaxies:active radiation mechanisms:non-thermal X-rays:galaxies

Local and non-local sources of airborne particulate pollution at beijing——The ratio of Mg/Al as an element tracer for estimating the contributions of mineral aerosols from outside beijing

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Science china Chemistry 2005年第3期48卷 253-264页

作者： HAN Lihui1, ZHUANG Guoshun1,2,3, SUN Yele1 & WANG Zifa3 1. The center for Atmospheric Environmental Study, department of Chemistry, beijing Normal university, beijing 100875, china 2. center for Atmospheric Chemistry Study, department of Environmental Science & engineering, Fudan university, Shanghai 200433, china 3. LAPC/NZC, Institute of Atmospheric physics, CAS, beijing 100029, china The center for Atmospheric Environmental Study Department of Chemistry Beijing Normal University Beijing China center for Atmospheric Chemistry Study Department of Environmental Science & Engineering Fudan University Shanghai China Institute of Atmospheric physics CAS LAPC/NZC Beijing China

A new element tracer technique has firstly been established to estimate the contri-butions of mineral aerosols from both inside and outside beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles （TSP）, 10%―70% of fine particles （PM2.5）, and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside beijing contributed 62% （38%―86%） of the total mineral aerosols in TSP, 69% （52%―90%） in PM10, and 76% （59%―93%） in PM2.5 in spring, and 69% （52%―83%）, 79% （52%―93%）, and 45% （7%―79%） in TSP, PM10, and PM2.5, respectively, in winter, while only20% in summer and autumn. The sources from outside beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in beijing. The contributions from outside Bei-jing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.

关键词： mineral aerosol local sources non-local sources dust storm re-suspended dust element tracer technique.

Coexistence of normal, super-, and hyper-deformation in nuclei: A study with angular momentum projection method

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Chinese Science Bulletin 2009年第3期54卷 358-363页

作者： SUN Yang1,2, ZHANG JingYe3, LONG GuiLu4,5 & WU ChengLi6,7 1 department of physics, Shanghai Jiao Tong university, Shanghai 200240, china 2 Joint Institute for Nuclear astrophysics, university of Notre Dame, Notre Dame, Indiana 46556, USA 3.department of physics and Astronomy, university of Tennessee, Knoxville, Tennessee 37996, USA 4 department of physics, tsinghua university, beijing 100084, china 5 center of Nuclear Theory, Lanzhou National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, china 6 department of physics, Xiamen university, Xiamen 361005, china 7 department of physics, Chung Yuan Christian university, Chung-Li, Taiwan 32023, china department of physics Shanghai Jiao Tong University Shanghai 200240 China Joint Institute for Nuclear astrophysics University of Notre Dame Notre Dame Indiana 46556 USA department of physics and Astronomy University of Tennessee Knoxville Tennessee 37996 USA department of physics Tsinghua University Beijing 100084 China center of Nuclear Theory Lanzhou National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China department of physics Xiamen University Xiamen 361005 China department of physics Chung Yuan Christian University Chung-Li Taiwan 32023 China

Angular-momentum-projected energy surface calculations for A ≈ 110 nuclei indicate three distinct energy minima occurring at different angular-momenta. These correspond to normal, super-, and hy- per-deformed shapes coexisting in one nucleus. 110Pd is studied in detail, with a quantitative prediction on super- and hyper-deformed spectra by the Projected Shell Model calculation. It is found that several other neighboring nuclei in the A-110 mass region, with the neutron number around 64, also exhibit clear super- and hyper-deformation minima in the projected calculation.

关键词：原子核光谱角动量能量

Archean relic body at lower crust in Sulu area:Evidence from magnetic data

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Chinese Science Bulletin 2003年第6期48卷 589-593页

作者： WU Qifan1,2, LU Fengxiang3, LIU Qingsheng3, ZHENG Jianping3, WANG Maoji2 & WU Wenli4 1. department of engineering physics, tsinghua university, beijing 100084, china 2. Aero Geophysical Survey & Remote Sensing center, beijing 100083, china 3. china university of Geosciences, Wuhan 430074, china 4. Institute of Geophysical & Geochemical Exploration, Langfang 065000, china Aero Geophysical Survey & Remote Sensing center Beijing 100083 China china university of Geosciences Wuhan 430074 China Institute of Geophysical & Geochemical Exploration Langfang 065000 China department of engineering physics Tsinghua University Beijing 100084 China

After the new 1︰1000000 aero magnetic data were processed and the three-dimensional inversion work was carried out, a vast high magnetic body northwestward was discovered. The magnetic body is located at the depth of about 20 km on the west side of Tanlu fault and at about 25 km on the east side of Tanlu fault beneath the Sulu area. There is a difference of vertical distance of 3—5 km in depth between both sides. We think that the magnetic body is an Archean metamorphic plate and belongs to the North china block. The discovery of the magnetic body is significant for us to reconstruct the structure model of the Sulu orogenic belt, delineate the suture of collision between the North china block and the Yangtze block, and estimate the depth of slipping surface when the eastside of Tanlu fault moved northward.

关键词：苏鲁地区地壳下层太古代残余体地球物理调查区域性磁场三维反演苏鲁造山带郯鲁断裂带大别-苏鲁超高压变质带

Physically-based approach to analyze rainfall-triggered landslide using hydraulic gradient as slide direction

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Journal of Zhejiang university-Science A(Applied physics & engineering) 2012年第12期13卷 943-957页

作者： Qi-hua RAN1,Dan-yang SU1,Qun QIAN1,Xu-dong FU2,Guang-qian WANG1,2,Zhi-guo HE3 (1department of Hydraulic engineering,Zhejiang university,Hangzhou 310058,china) (2State Key Laboratory of Hydroscience and engineering,tsinghua university,beijing 100084,china) (3department of Ocean Science and engineering,Zhejiang university,Hangzhou 310058,china) department of Hydraulic engineering Zhejiang University

An infinite slope stability numerical model driven by the comprehensive physically-based integrated hydrology model(InHM) is *** this approach,the failure plane is assumed to be parallel to the hydraulic gradient instead of the slope *** method helps with irregularities in complex terrain since depressions and flat areas are allowed in the *** present model has been tested for two synthetic single slopes and a small catchment in the Mettman Ridge study area in Oregon,United States,to estimate the shallow landslide *** results show that the present approach can reduce the simulation error of hydrological factors caused by the rolling topography and depressions,and is capable of estimating spatial-temporal variations for landslide susceptibilities at simple slopes as well as at catchment scale,providing a valuable tool for the prediction of shallow landslides.

关键词： Shallow landslide Infinite slope stability model Hydraulic gradient Physically-based hydrology model Integrated hydrology model(InHM)

Enhancement of magnetism of Zn0.95Co0.05O films by p-type Cu+ doping

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Progress in Natural Science:Materials International 2011年第1期21卷 31-35页

作者： Wei-chang HAO~(1,5),Jian-jun LI~2,Huai-zhe XU~3,Jia-ou WANG~4,Tian-min WANG~1 1.center of Materials physics and Chemistry,Beihang university,beijing 100083,china 2.department of Materials Science and engineering, Anhui university of Science and Technology,Huainan 232001,china 3.department of physics,Beihang university,beijing 100083,china 4.beijing Synchrotron Radiation Facility,Institute of High Energy physics, Chinese Academy of Sciences,100049,china 5.Key Laboratory of Micro-nano Measurement,Manipulation and physics, Ministry of Education,Beihang university,beijing 100191,china center of Materials physics and Chemistry Beihang University department of Materials Science and engineering Anhui University of Science and Technology department of physics Beihang University Key Laboratory of Micro-nano Measurement Manipulation a

Zn0.95Co0.05O and Zn0.91Co0.05Cu0.04O thin films were fabricated on Si（111） substrate by the reactive magnetron sputtering method at different O-Ar *** characterizations by X-ray diffractometry（XRD）,X-ray photo-electronic spectrum（XPS）, and electron paramagnetic resonance（EPR） indicate that the doped Cu ions substitute the Zn2+ions in the ZnO *** doped Cu ions are in Cu+and Cu2+mixture valence *** ferromagnetism of the Zn0.91Co0.05Cu0.04O film increases gradually the increasing Cu+ions *** results indicate that the increase of ferromagnetism is not owing to the magnetic contribution of Cu+ions themselves,but owing to the enhancement of magnetic interaction between Co ions,which suggests that p-type doping of Cu+ions plays an important role in mediating the ferromagnetic coupling between Co ions.

关键词： Zn0.95Co0.05O films Zn0.91Co0.05Cu0.04O films magnetic semiconductors magnetic coupling co-doping

Effect of electric field,stress and environment on delayed fracture of a PZT-5 ferroelectric ceramic

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Science china(physics,Mechanics & Astronomy) 2005年第1期48卷 89-100页

作者： WANG Yi, SU Yanjing, CHU Wuyang & QIAO Lijie department of Material physics, university of Science and Technology beijing, beijing 100083, china School of Mechanic and Electric Control engineering, beijing Jiaotong university, beijing 100044, china department of Material physics University of Science and Technology Beijing Beijing 100083 China School of Mechanic and Electric Control engineering Beijing Jiaotong University Beijing 100044 China

The combined effect of electric and mechanical loading on fracture of a PZT-5 ferroelectric ceramic in silicone oil has been investigated using a single edge notched specimen. The results show that the fracture toughness and the threshold stress intensity factor of delayed fracture in silicone oil, i.e. stress corrosion cracking, decrease linearly with the increasing applied electric field, either positive or negative. For the PZT-5 ferroelectric ceramics, delayed fracture in silicone oil under sustained positive or negative field can occur, and the threshold field for delayed fracture under sustained positive or negative field decreases linearly with applied stress intensity factor. The combined effect of electric and mechanical loading on delayed fracture in silicone oil includes fieldenhancing delayed fracture under sustained load and stress-enhancing delayed fracture in silicone oil under sustained field.

关键词： PZT-5 ferroelectric ceramics, fracture toughness, delayed fracture under sustained load, delayedfracture under sustained electric field.

Vacuum induced transparency and slow light phenomena in a two-level atomic ensemble controlled by a cavity

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Chinese physics B 2015年第9期24卷 240-244页

作者：郭玉杰聂文杰 department of physics Tsinghua University beijing Computational Science Research center department of Applied physics East China Jiaotong University

We study the optical properties of a two-level atomic ensemble controlled by a high-finesse cavity. Even though the cavity is initially in the vacuum state in the absence of external driving, the probe response of the atomic ensemble can be dramatically modified. When the collectively enhanced atom–cavity coupling is strong enough and the cavity decay rate is much smaller than the atomic damping rate, an electromagnetically induced transparency-like coherent phenomenon emerges with a dip absorption for the response of the two-level atoms in the cavity without driving, and thus is called vacuum induced transparency. We also show the slow light with very low group velocity in such an atomic ensemble.

关键词： electromagnetically induced transparency two-level atomic ensemble vacuum slow light

Wave decomposition phenomenon and spectrum evolution over submerged bars

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Acta Oceanologica Sinica 2009年第3期28卷 82-92页

作者： LI Benxia YU Xiping National Marine Environmental Forecasting center State Oceanic Administration Beijing 100081China department of Hydraulic engineering Tsinghua University Beijing 100084 China

Wave decomposition phenomenon and spectrum evolution over submerged bars are investigated by a previously developed numerical model. First, the computed free surface displacements of regular waves at various locations are compared with the available experimental data to confirm the validity of the numerical model, and satisfactory agreements are obtained. In addition, variations of decomposition characteristics with incident wave parameters and the change of energy spectrum for regular waves are also studied. Then the spectrum evolution of irregular waves over submerged bars, as well as the influence of incident peak wave period and the steepness of the front slope of the bar on spectrum evolution, is investigated. Wave decomposition and spectral shape are found to be significantly influenced by the incident wave conditions. When the upslope of the bar becomes 1：2, the length of the slope becomes shorter and will not benefit the generation of high frequency energy, so spectrum evolution is not significant.

关键词： wave decomposition spectrum evolution nonlinear waves irregular waves submerged bars