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Combined imbibition system with black nanosheet and low-salinity water for improving oil recovery in tight sandstone reservoirs

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Petroleum Science 2023年第3期20卷 1562-1571页

作者： Dao-Yi Zhu Yu-Heng Zhao Hong-jun Zhang Qi Zhao Chen-Yang Shi jun-Hui Qin Zheng-hao Su gui-Qi Wang Yang Liu Ji-Rui Hou China University of Petroleum Bejing102249China

Nanomaterials and low-salinity water(LSW)are two popular enhanced oil recovery(EOR)methods that have been widely studied in recent *** former is used for in-depth conformance improvement and the latter for microscopic oil displacement(by altering the potential and contact angle).However,there are few literature on combining them to achieve synergistic effects,especially for tight sandstone *** on the reservoir conditions of the Jimusar Oilfield,this study investigated the oil recovery mechanism of the combined imbibition system,which was composed of black nanosheet(BN)and *** performances including decreasing interfacial tension,emulsification,and wettability alterations were *** imbibition differences between the single system of BN and LSW and the combined BN-LsW imbibition system were then *** showed that the combined imbibition system had a better emulsification effect on the crude oil and could also alter the wettability of the core ***,the combined system could increase both the imbibition rate and the ultimate oil *** nuclear magnetic T2 spectrum also indicated that the addition of black nanosheets could divert more fluid into small pores and thus improve the microscopic sweep efficiency.

关键词： Low-salinity water Black nanosheet Combined imbibition system Wettability alteration Improved oil recovery

Modeling stochastic mortality with O-U type processes

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Applied Mathematics(A Journal of Chinese Universities) 2018年第1期33卷 48-58页

作者： ZHENG Jing TONG Chang-qing ZHANG gui-jun College of Economics Hangzhou Dianzi University

Modeling log-mortality rates on O-U type processes and forecasting life expectancies are explored using U.S. data. In the classic Lee-Carter model of mortality, the time trend and the age-specific pattern of mortality over age group are linear, this is not the feature of mortality model. To avoid this disadvantage, O-U type processes will be used to model the log-mortality in this paper. In fact, this model is an AR(1) process, but with a nonlinear time drift *** on the mortality data of America from Human Mortality database(HMD), mortality projection consistently indicates a preference for mortality with O-U type processes over those with the classical Lee-Carter model. By means of this model, the low bounds of mortality rates at every age are given. Therefore, lengthening of maximum life expectancies span is estimated in this paper.

关键词： mortality stochastic forecasting O-U type process

Possible Contribution of Mature γ-ray Pulsars to Cosmic-ray Positrons

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Chinese Journal of Astronomy and Astrophysics 2008年第1期8卷 87-95页

作者： Quan-gui Gao Ze-jun Jiang Li Zhang National Astronomical Observatories / Yunnan Observatories Chinese Academy of Sciences Kunming 650011 Department of Physics Yunnan University Kunming 650091

We restudy the possible contribution of mature gamma-ray pulsars to cosmic ray positrons based on the new version of outer gap model. In this model, the inclination angle and average properties of the outer gap are taken into account, and more mature pulsars can have the outer gap and emit high energy photons. Half of the primary particles in the outer gaps will flow back toward the star surface and emit synchrotron photons, which can produce electron/positron pairs by the cascade of pair production. Some of these pairs will escape from the light cylinder and be accelerated to relativistic energies in the pulsar wind driven by low-frequency electromagnetic waves. Using a Monte Carlo method, we obtain a sample of mature gamma-ray pulsars and then calculate the production of the positrons from these pulsars. The observed excess of cosmic positrons can be well explained by this model.

关键词： stars pulsars general - acceleration of particles - ISM cosmic rays

Effect of TiO2 on reduction behavior of Cr2O3 in CaO-SiO2-Al2O3-MgO-TiO2-Cr2O3 by carbon from Fe-C melt

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Journal of Iron and Steel Research International 2020年第10期27卷 1145-1152页

作者： jun-yi Xiang gui-shang Pei Wei Lv Bao-hua Li gui-bao Qiu Xue-wei Lv College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing 400044China

The chromium-bearing titanomagnetite ore will turn to be the important raw material for blast furnace process in Panxi area,*** reduction behavior of Cr2O3 between CaO-SiO2-Al2O3-TiO2-Cr2O3 and Fe-C systems was *** effect of TiO2 content in the slag system on the reduction of Cr2O3,TiO2,and SiO2 and the con sumption of C in hot metal was investigated by both theoretical calculation and physical *** theoretical calculation results reveal that higher reduction temperature promotes the reduction of Cr and Ti,while high basicity and TiO2 content have little influence on the reduction of chromium but significantly influence the reduction of *** smelting reduction experiment results show that the content of Cr in hot metal significantly in creases with extendi ng the reduction time and decreases with the increase in TiO2 ***,the content of Ti in hot metal significantly increases as the TiO2 increases,reaching 0.073,0.085,0.107,and 0.121 wt.%for 5,10,15,and 20 wt.%of TiO2 input,*** studies proved that the reduction of Cr2O3 was a first-order *** addition of TiO2 inhibited the reduction of Cr2O3 and resulted in the decrease in reaction rate constant.

关键词： Smelting reduction Titanomagnetite Blast furnace slag Chromium oxide Titanium oxide

Fragmentation Effects on Diversity of Wasp Community and Its Impact on Fig／Fig Wasp Interaction in Ficus racemosa L.

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Journal of Integrative Plant Biology 2005年第1期47卷 20-26页

作者： Rui-WuWANG Cheng-YunYANG gui-FangZhao jun-XingYANG KunmingInstituteofZoology theChineseAcademyofSciencesKunming650223China／／GraduateSchooloftheChineseAcademyofSciencesBeijing100039China KunmingInstituteofZoology theChineseAcademyofSciencesKunming650223China／／CollegeofLifeSciencesNorthwestUniversityXi＇an710069China CollegeofLifeSciences NorthwestUniversityXi＇an710069China KunmingInstituteofZoology theChineseAcademyofSciencesKunming650223China

Abstract: Habitat fragmentation usually results in alteration of species composition or biological communities. However, little is known about the effect of habitat fragmentation on the fig/fig wasp system. In this study, we compared the structure of a fig wasp community and the interaction between figs and fig wasps of Ficus racemosa L. in a primary forest, a locally fragmented forest and a highly fragmented forest. Our results show that, in the highly fragmented forest, the proportion of pollinator wasps is lower and the proportion of non-pollinator wasps is higher compared with the primary forest and locally fragmented forest. The proportion of fruits without pollinator wasps in mature fruits is also greatly increased in the highly fragmented forest. The proportion of galls in all female flowers increases in the highly fragmented forest, whereas the proportion of viable seeds does not change considerably. The disruption of groups of fig trees results in a decrease in pollinator wasps and even might result in the extinction of pollinator wasps in some extreme cases, which may transform the reciprocal interaction between figs and fig wasps into a parasite/host system. Such an effect may lead to the local extinction of this keystone plant resource of rain forests in the process of evolution, and thereby, may change the structure and function of the tropical rain forest.

关键词： Ficus racemosa L. fig fig wasp fragmentation tropical rain forest

Ghost-Retina Net:Fast Shadow Detection Method for Photovoltaic Panels Based on Improved Retina Net

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Computer Modeling in Engineering & Sciences 2023年第2期134卷 1305-1321页

作者： jun Wu Penghui Fan Yingxin Sun Weifeng gui School of Physics and Electronic Information Engineering Henan Polytechnic UniversityJiaozuo454000China

Based on the artificial intelligence algorithm of RetinaNet,we propose the Ghost-RetinaNet in this paper,a fast shadow detection method for photovoltaic panels,to solve the problems of extreme target density,large overlap,high cost and poor real-time performance in photovoltaic panel shadow ***,the Ghost CSP module based on Cross Stage Partial(CSP)is adopted in feature extraction network to improve the accuracy and detection *** on extracted features,recursive feature fusion structure ismentioned to enhance the feature information of all *** introduce the SiLU activation function and CIoU Loss to increase the learning and generalization ability of the network and improve the positioning accuracy of the bounding box regression,***,in order to achieve fast detection,the Ghost strategy is chosen to lighten the size of the *** results of the experiment show that the average detection accuracy(mAP)of the algorithm can reach up to 97.17%,the model size is only 8.75 MB and the detection speed is highly up to 50.8 Frame per second(FPS),which can meet the requirements of real-time detection speed and accuracy of photovoltaic panels in the practical *** realization of the algorithm also provides new research methods and ideas for fault detection in the photovoltaic power generation system.

关键词： Deep learning intensive object detection photovoltaic panel shadow Ghost module retinanet

Spin Polarization Properties of Na Doped Meridianal Tris（8-Hydroxyquinoline） Aluminum Studied by First Principles Calculations

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Chinese Physics Letters 2014年第4期31卷 193-196页

作者： REN jun-Feng YUAN Xiao-Bo HU gui-Chao College of Physics and Electronics Shandong Normal University Jinan 250014

We theoretically investigate the electronic structure and spin polarization properties of Na-doped meridianal tris（S-hydroxyquinoline） aluminum （Alq3） by first principles calculations. It is found that the spin density is distributed mainly in the Alq3 part in the Alq3：Na complex. Electron charge transfer takes place from the Na atom to the Alq3 molecule, which induces asymmetric changing of the molecule bond lengths, thus the spin density distribution becomes asymmetric. Spin polarization of the complex originates from the preferable filling of the spin-split nitrogen and carbon p-orbitals because of the different bond length changes of the Aiq3 molecule upon Na doping.

关键词： SPIN polarization ELECTRONIC structure SODIUM -- Spectra SEMICONDUCTOR doping HYDROXYQUINOLINE CHARGE exchange

INTERDIFFUSION KINETICS OF MISCIBLE POLYMER/POLYMER LAMINATES INVESTIGATED BY ATOMIC FORCE MICROSCOPY

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Chinese Journal of Polymer Science 2013年第6期31卷 870-878页

作者： Yong-gui Liao Meng-jun Peng Feng-zhen Liu 解孝林 Key Laboratory for Large-Format Battery Materials and System Ministry of Education School of Chemistry and Chemical Engineering Huazhong University of Science and Technology Wuhan National High Magnetic Field Center Huazhong University of Science and Technology

The miscibility of poly（vinyl chloride）/poly（n-butyl methacrylate）（PVC/PnBMA） blend and the interdiffusion kinetics of PVC/PnBMA laminates have been investigated by differential scanning calorimetry （DSC） and atomic force microscopy （AFM）, respectively. This blend exhibited a lower critical solution temperature behavior. Below 120 ℃, DSC results showed each blend with different PVC contents exhibited only a single glass transition temperature which increased with PVC content, indicating that PVC and PnBMA were miscible. After PVC/PnBMA laminates were annealed at different temperature for different time, a smooth cross-section across interface was prepared by ultramicrotoming. Combined with topography and phase images of tapping mode AFM, the relative concentration profile, interface width and the relationship between interface width and annealing time could be obtained. In a regime of rubbery/rubbery interdiffusion, the diffusion obeyed a typical Fickian Case-I behavior where the interface width was proportional to the square root of annealing time. The mutual diffusion coefficient was in good agreement with that obtained from DSC and positron annihilation lifetime spectroscopy. However, in the regime of glassy/rubbery interdiffusion, the diffusion followed a typical Case-II behavior where the interface width was proportional to annealing time. These results imply that AFM is a reliable and powerful tool for the investigation of polymer/polymer interdiffusion at a level of polymer chain size.

关键词： Miscibility Polymer interface Interdiffusion Kinetics Atomic force microscopy.

Development and application of an instrument for simulating wetting-drying cycles of expansive soils under loads

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Journal of Mountain Science 2018年第11期15卷 2552-2560页

作者： DONG jun-gui LV Hai-bo WU Wei School of Civil Engineering and Transportation South China University of Technology Guangzhou 510641 China College of Civil Engineering and Architecture Guilin University of Technology Guilin 541004 China

Alternating rainfall and evaporation in nature severely impact the shear strength of expansive soils. This study presents an instrument for simulating the effect of wetting–drying cycles on the strength of expansive soils under different loads, and its testing error is verified. With this instrument,direct shear tests were performed on samples experiencing 0-6 cycles under vertical loads of 0 kPa,5 kPa, 15 kPa, and 30 k Pa. The results found that this instrument provides a new method for evaluating the effects of wetting–drying cycles on soils, and this method represents actual engineering conditions more accurately than do preexisting methods. It accurately controls the water content within 1% while simulating the specified loads at different soil *** is significantly affected by wetting–drying cycles, while the friction angle is not as sensitive to these cycles. Decrease in shear strength can be attributed to the fissures in soils caused by wetting–drying cycles. The existence of vertical loads effectively restricts shrinkage fissuring and cohesion attenuation, consequently inhibiting the attenuation of shear strength.

关键词： Expansive soils Wetting-drying cycle Instrument Load Shear strength