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Experimental Investigation on Flame Characterization and Temperature Profile of Single/Multiple Pool Fire in Cross Wind

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Journal of Thermal Science 2021年第1期30卷 324-332页

作者： CHEN zhen WEI Xiaolin li Teng Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

An experimental study was carried out to investigate the flame characterization and temperature profile for single and multiple pool fire with the influence of cross *** were 13 test cases in total,categorized into circle and rectangle fuel pans,with diameter(or equivalent diameter)ranged from 50 mm to 300 *** was used for the fuel of pool *** K-type thermocouples were arranged around the flame to monitor the flame temperature,while the flame tilt angle was measured based on the photograph of flame for different ***,it can be found that there are three phases,including preheating,steady burning and extinguishing phase,during the flame *** maximum temperature near the fuel surface is~1040 K,which is higher than that of flame plume(~600 K),in the steady burning phase of circle single pool fire(D=300 mm),while the average burning rate is~1.525 g/*** addition,the burning rates of all cases were measured and compared with the current predicted ***,the flame morphology of single/multiple pool fire at different cross wind speed(ranging from 0 to 3.5 m/s)was analyzed,and it is found that the results for single pool fire agree with Thomas model and AGA model well,which are not suitable for multiple pool ***,the temperature profile of different case was measured with various wind speed.

关键词： pool fire temperature profile flame characteristic kerosene cross wind

Molecular Uniting Set Identified Characteristic(MUSIC)of Organic Optoelectronic Material

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Chinese Journal of Chemistry 2022年第19期40卷 2356-2370页

作者： Arui Huang Qianqian li zhen li Hubei Key Lab on Organic and Polymeric Opto-Electronic Materials Sauvage Center for Molecular SciencesDepartment of ChemistryWuhan UniversityWuhanHubei430072 China Institute of Molecular Aggregation Science Tianjin UniversityTianjin300072 China

Researchers investigated the organic optoelectronic materials and facilitated their development in organic light-emitting diodes(OLEDs),chemo-and biosensors,organic solar cells,data storage,and anticounterfeiting *** make up molecules through chemical bonds,and molecular aggregates are formed through weak intermolecular *** opto-electronic performance of these materials depends on not only the properties of the well-designed molecules with specific function groups,but also their aggregate *** molecular aggregates in the form of nanoparticles can be applied in biological imaging,and films can be applied to photovoltaic and photodeformable devices,in which,the alignment of optoelectronic molecules can be either an ordered crystalline or an amorphous ***,the crystalline materials could be deeply investigated by single crystal/powder X-ray diffraction analysis,which could provide the accurate information about molecular conformations,interactions and packing *** afforded a convenient way to investigate the possible relationship between molecular aggregates and opto-electronic *** various opto-electronic materials,organic room temperature phosphorescence(RTP)materials exhibit the extremely sensitive luminescence property to molecular aggregates,even the dynamic properties can be detected by the tiny change of molecular ***,we selected the organic RTP emission as the output information of molecular aggregates,and afforded typical examples to find the possible relation between RTP effect and molecular ***,molecular packing can be adjusted by the external force as light,mechanical force,temperature,electric field,and so on,as well as the molecular structures as the building blocks,and the systematic investigation in the dynamic and static aggregation structures is of great value to the design of various optoelectronic *** review discusses the relationship among molec

关键词： Aggregation Structure-activity relationships Room temperature phosphorescence Organic opto-electronic material Substituent effects

Effects of different Ca^(2+) behavior patterns in the electric field on membrane fouling formation and removal of trace organic compounds

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Journal of Environmental Sciences 2022年第1期34卷 292-300页

作者： zhen Du Min Ji Ruying li School of Environmental Science and Engineering Tianjin UniversityTianjin 300350China

The effects of Ca^(2+) on membrane fouling and trace organic compounds(TrOCs)removal in an electric field-assisted microfiltration system were investigated in the presence of Na^(+) alone for *** the electric field,negatively charged bovine serum albumin(BSA)migrated towards the anode far away from the membrane surface,resulting in a 42.9%transmembrane pressure(TMP)reduction in the presence of Na^(+) at 1.5 *** contrast,because of the stronger charge shielding of Ca^(2+),the electrophoretic migration of BSA was limited and led to a neglectable effect of the electric field(1.5 V)on membrane ***,under 3 V applied voltage,the synergistic effects of electrochemical oxidation and bridging interaction between Ca^(2+) and BSA promoted the formation of denser settleable flocs and a thinner porous cake layer,which alleviated membrane fouling with a 64.5%decrease in TMP and nearly 100%BSA *** Tr OCs elimination increased with voltage and reached29.4%–80.4%at 3 *** electric field could prolong the contact between Tr OCs and strong oxidants generated on the anode,which enhanced the Tr OCs ***,a stronger charge shielding ability of Ca^(2+) weakened the electric field force and thus lowered the Tr OCs removal.

关键词： Electric field Membrane fouling Ca^(2+) Flocs formation Trace organic compounds

Testing High-Dimensional Nonparametric Behrens-Fisher Problem

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Journal of Systems Science & Complexity 2022年第3期35卷 1098-1115页

作者： MENG zhen li Na YUAN Ao Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Biostatistics Bioinformatics and BiomathematicsGeorgetown UniversityWashington 20057USA

For high-dimensional nonparametric Behrens-Fisher problem in which the data dimension is larger than the sample size,the authors propose two test statistics in which one is U-statistic Rankbased Test(URT)and another is Cauchy Combination Test(CCT).CCT is analogous to the maximumtype test,while URT takes into account the sum of squares of differences of ranked samples in different dimensions,which is free of shapes of distributions and robust to *** asymptotic distribution of URT is derived and the closed form for calculating the statistical significance of CCT is *** simulation studies are conducted to evaluate the finite sample power performance of the statistics by comparing with the existing *** simulation results show that our URT is robust and powerful method,meanwhile,its practicability and effectiveness can be illustrated by an application to the gene expression data.

关键词： Cauchy combination test nonparametric Behrens-Fisher problem rank-based test U-statistic

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Stability Mechanism of Laser-induced Fluorinated Super-hydrophobic Coating in Alkaline Solution

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Journal of Bionic Engineering 2022年第1期19卷 113-125页

作者： Haoyang li Yanling Tian zhen Yang School of Mechanical Engineering Tianjin UniversityTianjin300350China Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyHong Kong999077China

Great attention has been focused on super-hydrophobic surfaces due to their fantastic *** chemicals are widely used to fabricate super-hydrophobic surfaces due to their convenience,simplicity,and high *** research has made extensively efforts on corrosion resistance of fluorinated super-hydrophobic surfaces in corrosive ***,rare papers focused on the underlying reasons of anticorrosion property and stability mechanism on the fluorinated super-hydrophobic coatings in alkaline ***,this work aims to reveal these mechanisms of fluorinated super-hydrophobic copper samples in strong alkaline solution(pH 13).Through the characterization of surface wettability and surface morphology,the laser-induced super-hydrophobic surface retained excellent stability after soaking in alkaline solution for 4 *** measurement of chemical compositions,the anticorrosion mechanism and stability mechanism of the fluorinated super-hydrophobic surface were ***,the hydroxyl ion(OH−)can further promote the hydrolysis reaction to improve the density and bonding strength of the fluoride ***,the electrochemical experiments(PDP and EIS tests)were conducted to validate the rationality of our proposed conclusions.

关键词： Fluoride Laser Super-hydrophobicity Alkaline corrosion Stability mechanism

Research progress on seismic imaging technology

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Petroleum Science 2022年第1期19卷 128-146页

作者： zhen-Chun li Ying-Ming Qu School of Geosciences China University of PetroleumQingdaoShandong266580China Shandong Provincial Key Laboratory of Deep Oil&Gas China University of PetroleumQingdaoShandong266580China

High-precision seismic imaging is the core task of seismic exploration,guaranteeing the accuracy of geophysical and geological *** the development of seismic exploration,the targets become more and more *** on complex media such as subsalt,small-scale,steeply dipping and surface topography structures brings a great challenge to imaging ***,the seismic imaging methods range from stacking-to migration-to inversion-based imaging,and the imaging accuracy is becoming increasingly *** review paper includes:summarizing the development of the seismic imaging;overviewing the principles of three typical imaging methods,including common reflection surface(CRS)stack,migration-based Gaussian-beam migration(GBM)and reverse-time migration(RTM),and inversion-based least-squares reverse-time migration(LSRTM);analyzing the imaging capability of GBM,RTM and LSRTM to the special structures on three typical models and a land data set;outlooking the future perspectives of imaging *** main challenge of seismic imaging is to produce high-precision images for low-quality data,extremely deep reservoirs,and dual-complex structures.

关键词： Common reflection surface stack Gaussian-beam migration Reverse-time migration Least-squares reverse-time migration

Spatiotemporal changes in vegetation net primary productivity in the arid region of Northwest China, 2001 to 2012

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Frontiers of Earth Science 2018年第1期12卷 108-124页

作者： zhen li Jinghu PAN College of Geographic and Environmental Science Northwest Normal University Lanzhou 730070 China

Net primary productivity （NPP） is recognized as an important index of ecosystem conditions and a key variable of the terrestrial carbon cycle. It also represents the comprehensive effects of climate change and anthropogenic activity on terrestrial vegetation. In this study, the temporal-spatial pattern of NPP for the period 2001-2012 was analyzed using a remote sensing-based carbon model （i.e., the Carnegie-Ames-Stanford Approach, CASA） in addition to other methods, such as linear trend analysis, standard deviation, and the Hurst index. Temporally, NPP showed a significant increasing trend for the arid region of Northwest China （ARNC）, with an annual increase of 2.327 g C. Maximum and minimum productivity values appeared in July and December, respectively. Spatially, the NPP was relatively stable in the temperate and warmtemperate desert regions of Northwest China, while temporally, it showed an increasing trend. However, some attention should be given to the northwestern warm-temperate desert region, where there is severe continuous degradation and only a slight improvement trend.

关键词： NPP CASA model remote sensing aridregion of Northwest China (ARNC)

Lateral abutment pressure distribution and evolution in wide pillars under the first mining effect

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International Journal of Mining Science and Technology 2023年第3期33卷 309-322页

作者： zhen Zhang zhen li Gang Xu Xiaojin Gao Qianjin liu zhengjie li Jiachen liu Coal Mining and Designing Branch China Coal Research InstituteBeijing 100013China CCTEG Coal Mining Research Institute Beijing 100013China Coal Mining&Designing Department Tiandi Science&Technology Co.Ltd.Beijing 100013China School of Civil Engineering Henan Polytechnic UniversityJiaozuo 454003China Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization Jiaozuo 454003China

The wide pillars are generally popular due to the high productivity and efficiency in Northwest *** distribution of lateral abutment pressure in coal pillars is important for mining *** reveal the effect of the first mining on the lateral abutment pressure distribution and evolution in wide pillars,an in-situ experiment,theoretical analysis and numerical simulation were ***,the field monitoring of lateral abutment pressure was conducted from the perspective of time and space in the Chahasu Coal Mine,Huangling No.2 Coal Mine and lingdong Coal Mine during the first *** on the field monitoring stress,a theoretical model was proposed to reveal the lateral abutment pressure *** methodology was demonstrated through a case *** at the distribution mechanism,a numerical experiment was conducted through the finite-discrete element method(FDEM).Last,field observations of borehole fractures were performed to further study the damage *** addition,two types of lateral abutment pressure evolution with mining advance were *** on the stress monitoring layout were proposed as *** results could provide foundations for strata control and disaster prevention in wide pillars in underground coal mines.

关键词： Wide pillar Lateral abutment pressure Pillar stress First mining effect Field monitoring

Genetic Approaches for Neural Circuits Dissection in Non-human Primates

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Neuroscience Bulletin 2023年第10期39卷 1561-1576页

作者： ling li zhen liu Institute of Neuroscience CAS Center for Excellence in Brain Science and Intelligence TechnologyCAS Key Laboratory of Primate NeurobiologyState Key Laboratory of NeuroscienceChinese Academy of SciencesShanghai 200031China Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology Shanghai 200031China University of Chinese Academy of Sciences Beijing 100049China

Genetic tools,which can be used for the morphology study of specific neurons,pathway-selective connectome mapping,neuronal activity monitoring,and manipulation with a spatiotemporal resolution,have been widely applied to the understanding of complex neural circuit formation,interactions,and functions in ***,similar genetic approaches have been tried in non-human primates(NHPs)in neuroscience studies for dissecting the neural circuits involved in sophisticated behaviors and clinical brain disorders,although they are still very *** this review,we introduce the progress made in the development and application of genetic tools for brain studies on *** also discuss the advantages and limitations of each approach and provide a perspective for using genetic tools to study the neural circuits of NHPs.

关键词： Genetic tool Neural circuit Non-human primate