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Characteristics of long period microtremor and validation of microtremor array measurements in inland areas of China

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Journal of Mountain Science 2016年第11期13卷 1910-1922页

作者： CHE Ai-lan ZHANG Teng-yu FENG Shao-kong School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University 800 Dongchuan-Road Shanghai 200240 China

To study the characteristics of long period microtremor and applicability of microtremor survey,we have made microtremor observations using long period seismometers of the China's mainland from coastal cities like Shanghai and Tianjin through Beijing,Xi'an,to the far inland cities of lanzhou and *** observation shows that the level of power spectrum of long period microtremors reduced rapidly from the coast to the inland ***,the energy of long period microtremors in Beijing,Xi'an,lanzhou and Tianshui area are only approximately ten-thousandth to thousandth of that in *** at the complexity of the underground structure in the far inland,a series of underground structure models with different distributions were assessed using three-dimensional,dynamic finite element method(FEM) *** results were used to evaluate microtremor survey methods and their limitations with regard to aggregate variability and thickness ***-wave reflections between layers with the change of underground structure distribution occurred,which have significant effect on the performance of the different field *** over a broad spectrum from which velocity-depth profiles were produced via inversion *** the thickness nor the shear waveVelocity V of the subsurface layer inversion results appeared over a large evaluation with increasing slope *** particular,when the angle of the model reached 45°,it could not be accurately evaluated using one-dimensional inversion ***,the array microtremor survey(AMS) was carried out in Shanghai City,*** AMS techniques do not have the layer sensitivity or accuracy(velocity and layer thickness) of borehole techniques,the obtained shear wave velocity structure is especially useful for earthquake disaster prevention and seismic analysis.

关键词： Long period microtremor Array Microtremor survey Power spectrum Inversion S-wave velocity structure

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An Iterative Algorithm for Angle-limited Three-dimensional Image Reconstruction

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Acta Mathematicae Applicatae Sinica 2008年第1期24卷 157-166页

作者： Gang-rong Qu Yong-sheng lan Ming Jiang School of Science Beijing Jiaotong University Beijing 100044 China School of Mathematical Sciences Peking University Beijing 100871 China

We establish an improved GP iterative algorithm for the extrapolation of band-limited function to fully 3-dimensional image reconstruction by the convolution-backprojection algorithm. Numerical experiments demonstrate... 详细信息

关键词： Fully 3-dimensional image reconstruction convolution-back projection algorithm angle-limited image reconstruction

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THE REBIRTH OF THE SERFS/SLAVES IN LHAGYARI——lan Zhigui and his photography of the Democratic Reform of Tibet

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China's Tibet 2009年第4期20卷 4-16页

作者： Zhou Aiming lan Zhigui（图）

In June of 1959,joining the working team,lan Zhigui headed to the palace of Lhagyari,the ruling lama in *** June 10th,he arrived at Tsethang Township and began recording his journey."Lhagyari is the stronghold of my *** setting off,I had a clear mind about my choice.I planned to take two months to complete my photography of‘the rebirth of the serfs/slaves in Lhagyari’."Since then,this unknown photographer formed a bond with the ancient palace and because of that he henceforth became one of the important figures in the photographic circles of China.

关键词：摄影师西藏改革开放民族团结民主主义

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Granulation by spray coating aqueous solution of ammonium sulfate to produce large spherical granules in a fluidized bed

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Particuology 2013年第5期11卷 483-489页

作者： Guanda Wang Ling Yang Rui lan Tingjie Wang Yong Jin Department of Chemical Engineering Tsinghua University

Spherical 2-4mm granules of ammonium sulfate （NH4）2SO4 are promising fertilizer for practical use, though only much smaller grains are being produced in industry. This work used coating granulation to produce large spherical granules of （NH4）2SO4 in a fluidized bed by spraying its aqueous solution onto 0.9-1.6 mm （NH4）2SO4 core particles. However, the overall coating efficiency was only 58% due to loss as dust by attrition of（NH4）2SO4 in the vent gas. By adding CaCO3 or SiO2 particles into the feed solution, the coating efficiency was increased to over 90%. This increase in coating efficiency was due to a change in the crystallization mechanism of（NH4）2SO4. The added CaC03 or Si02 particles provided a heterogeneous surface that induced （NH4）2S04 to crystallize uniformly to form a more compact structure less susceptible to attrition.

关键词： Ammonium sulfateSpray coatingGranulationFluidized bedHeterogeneous crystallization

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A Nowcasting Technique Based on Application of the Particle Filter Blending Algorithm

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Journal of Meteorological Research 2017年第5期31卷 931-945页

作者： yuanzhao chen hongping lan xunlai chen wenhai zhang meteorological bureau of shenzhen municipality Shenzhen 518040 shenzhen key laboratory of severe weather in south china Shenzhen 518040 shenzhen academy of severe storm science Shenzhen 518040

To improve the accuracy of nowcasting, a new extrapolation technique called particle filter blending was con- figured in this study and applied to experimental nowcasting. Radar echo extrapolation was performed by using the radar mosaic at an altitude of 2.5 km obtained from the radar images of 12 S-band radars in Guangdong Province, China. The first bilateral filter was applied in the quality control of the radar data; an optical flow method based on the lucas-Kanade algorithm and the Harris corner detection algorithm were used to track radar echoes and retrieve the echo motion vectors; then, the motion vectors were blended with the particle filter blending algorithm to estimate the optimal motion vector of the true echo motions; finally, semi-Lagrangian extrapolation was used for radar echo extrapolation based on the obtained motion vector field. A comparative study of the extrapolated forecasts of four precipitation events in 2016 in Guangdong was conducted. The results indicate that the particle filter blending al- gorithm could realistically reproduce the spatial pattern, echo intensity, and echo location at 30- and 60-min forecast lead times. The forecasts agreed well with observations, and the results were of operational significance. Quantitat- ive evaluation of the forecasts indicates that the particle filter blending algorithm performed better than the cross-cor- relation method and the optical flow method. Therefore, the particle filter blending method is proved to be superior to the traditional forecasting methods and it can be used to enhance the ability of nowcasting in operational weather forecasts.

关键词： radar echo particle filter blending bilateral filter semi-Lagrangian extrapolation nowcasting

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Control of mould level fluctuation through the modification of steel composition

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International Journal of Minerals,Metallurgy and Materials 2013年第2期20卷 138-145页

作者： Yang Li Xiao-huan Zhang Peng lan Jia-quan Zhang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

Periodic mould level fluctuation （MLF） during slab casting is a bottleneck for upgrading the surface quality and casting speed especially for hypoperitectic （HP） or ultralow carbon steels. The uneven growth of the initially solidified shell is verified to be one of the important inducements to MLF due to related unsteady bulging in the secondary cooling zone. It is shown that the solidification mode of steels and the contraction behavior can be modified through chemical composition optimization within given composition limits, For high strength low alloy （HSLA） steels, the actual peritectic points calculated by Thermo-Calc software may change remarkably with the slight variations of alloying element contents. Accordingly, the narrow limit of chemical composition of HP steels through optimization is proven to be one of the effective factors to control the popular MLF phenomenon during slab casting.

关键词： low carbon steel continuous casting solidification composition optimization

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An Easily Implementable Algorithm for Efficient Projection onto the Ordered Weighted l_(1)Norm Ball

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Journal of the Operations Research Society of China 2023年第4期11卷 925-940页

作者： Yong-Jin Liu Jia-Jing Xu lan-Yu Lin School of Mathematics and Statistics Fuzhou UniversityFuzhou350108FujianChina

This paper concerns with efficient projection onto the ordered weighted l_(1)norm ball,which is equivalent to the problem of finding projector onto the intersection of the monotone nonnegative cone and an affine *** on Lagrangian relaxation and secant approximation method,we propose an easily implementable yet efficient algorithm to solve the projection problem which is proved to terminate after a finite number of ***,we design efficient implementations for our algorithm and compare it with a semismooth Newton(SSN)algorithm and a root-finding(Root-F)*** results on a diversity of test problems show that our algorithm is superior than SSN and Root-F.

关键词： Lagrangian relaxation secant method ordered weighted l_(1)norm ball

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The Two Main Mechanisms of Glacier Lake Outburst Flood in Tibet,China

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Journal of Mountain Science 2013年第2期10卷 239-248页

作者： LIU Jing-jing TANG Chuan CHENG Zun-lan Key Laboratory of Mountain Hazards and Surface Process Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences State Key Laboratory of Geohazard Preventions Graduate School of Chinese Academy of Sciences

With the global warming,the disasters of Glacier Lake Outburst Flood(GLOF) have taken place frequently in Tibet in recent years and attracted more and more attention.A systematic survey was conducted on the 19 GLOFs in Tibet to study their two main *** indicated that all the events occurred in end-moraine lakes,and the outburst occurred partially and *** the breach had the shape of an arc or a trapezoid in overflow outburst and its top width was 3-5 times more than the *** two main mechanisms of GLOFs in Tibetan end-moraine Lake were overflow and piping,and the overflow mechanism caused by iceberg collapse was dominated in most cases.A formula was proposed to calculate the critical thickness of iceberg tongue that determines the *** analysis of the moraine materials revealed that seepage deformation is crucial in the outburst ***,we conducted a case study of the Guangxiecuo Lake to show its possible process of outburst and estimated the peak discharge of the resulted flood.

关键词： Glacier Lake Outburst Flood End-moraine Lake Outburst mechanism Overflow Piping Tibet

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Early-Awareness Collision Avoidance in Optimal Multi-Agent Path Planning With Temporal Logic Specifications

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IEEE/CAA Journal of Automatica Sinica 2023年第5期10卷 1346-1348页

作者： Yiwei Zheng Aiwen Lai Xiao Yu Weiyao lan the Department of Automation Xiamen UniversityXiamen 361005 the Key Laboratory of Control and Navigation(Xiamen University) Fujian Province UniversityXiamen 361005China the Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361005China

Dear Editor,This letter investigates a multi-agent path planning problem in a road network with the requirement of avoiding collisions among all agents in the partitioned *** first abstract the agents to a set of transition systems,and construct a team transition system from these individual systems.A mechanism is designed for the team transition system to detect all collisions within the synthesized run.

关键词： agent Temporal individual

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Outcome prediction value of National Early Warning Score in septic patients with community-acquired pneumonia in emergency department: A single-center retrospective cohort study

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World Journal of Emergency Medicine 2020年第4期11卷 206-215页

作者： Hai-jiang Zhou Tian-fei lan Shu-bin Guo Emergency Medicine Clinical Research Center Beijing Chao-yang HospitalCapital Medical University&Beijing Key Laboratory of Cardiopulmonary Cerebral ResuscitationBeijingChina Department of Allergy Beijing Shijitan HospitalCapital Medical UniversityBeijingChina

BACKGROUND:To evaluate the accuracy of National Early Warning Score(NEWS)in predicting clinical outcomes(28-day mortality,intensive care unit[ICU]admission,and mechanical ventilation use)for septic patients with community-acquired pneumonia(CAP)compared with other commonly used severity scores(CURB65,Pneumonia Severity Index[PSI],Sequential Organ Failure Assessment[SOFA],quick SOFA[qSOFA],and Mortality in Emergency Department Sepsis[MEDS])and admission lactate ***:Adult patients diagnosed with CAP admitted between January 2017 and May 2019 with admission SOFA≥2 from baseline were *** characteristics were *** primary outcome was the 28-day mortality after admission,and the secondary outcome included ICU admission and mechanical ventilation *** prediction value of parameters above was compared using receiver operating characteristics(ROC)*** regression analyses were carried out to determine the risk factors for the 28-day ***-Meier survival curves were plotted and compared using optimal cut-off values of qSOFA and ***:Among the 340 enrolled patients,90 patients were dead after a 28-day follow-up,62 patients were admitted to ICU,and 84 patients underwent mechanical *** single predictors,NEWS achieved the largest area under the receiver operating characteristic(AUROC)curve in predicting the 28-day mortality(0.861),ICU admission(0.895),and use of mechanical ventilation(0.873).NEWS+lactate,similar to MEDS+lactate,outperformed other combinations of severity score and admission lactate in predicting the 28-day mortality(AUROC 0.866)and ICU admission(AUROC 0.905),while NEWS+lactate did not outperform other combinations in predicting mechanical ventilation(AUROC 0.886).Admission lactate only improved the predicting performance of CURB65 and qSOFA in predicting the 28-day mortality and ICU ***:NEWS could be a valuable predictor in septic patients with CAP in emergency depa

关键词： Community-acquired pneumonia Sepsis National Early Warning Score(NEWS) Intensive care unit Emergency departments

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