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Experimental investigation on using CO_(2)/H_(2)O emulsion with high water cut in enhanced oil recovery

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Petroleum Science 2024年第2期21卷 974-986页

作者： Xi-Dao Wu Peng Xiao Bei Liu Guang-Jin Chen Jian-Hua Pang state Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China ocean Intelligence Technology Center Shenzhen Institute of Guangdong Ocean UniversityShenzhen518120GuangdongChina

CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility ***,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely *** this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil ***,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT ***,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary ***,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were *** results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) *** inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was ***_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water ***,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,*** work may provide guidelines for EOR using CO_(2) emulsions with high water cut.

关键词： CO_(2)/H_(2)O emulsion High water cut CO_(2) mobility control Enhanced oil recovery

Is a direct numerical simulation(DNS)of Navier-Stokes equations with small enough grid spacing and time-step definitely reliable/correct?

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Journal of ocean Engineering and Science 2024年第3期9卷 293-310页

作者： Shijie Qin Yu Yang Yongxiang Huang Xinyu Mei Lipo Wang Shijun Liao School of ocean and Civil Engineering Shanghai Jiao Tong UniversityShanghai 200240China state Key Laboratory of Marine Environmental Science College of Ocean and Earth SciencesXiamen UniversityXiamen 361102China UM-SJTU Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China state Key Laboratory of ocean Engineering Shanghai 200240China

Turbulence is strongly associated with the vast majority of fluid flows in nature and ***,results given by the direct numerical simulation(DNS)of Navier-Stokes(NS)equations that relate to a famous millennium problem are widely regarded as‘reliable’benchmark solutions of turbulence,as long as grid spacing is fine enough(*** than the minimum Kolmogorov scale)and time-step is small enough,say,satisfying the Courant-Friedrichs-Lewy condition(Courant number<1).Is this really true?In this paper a two-dimensional sustained turbulent Kolmogorov flow driven by an external body force governed by the NS equations under an initial condition with a spatial symmetry is investigated numerically by the two numerical methods with detailed comparisons:one is the traditional DNS,the other is the‘clean numerical simulation’(CNS).In theory,the exact solution must have a kind of spatial symmetry since its initial condition is spatially ***,it is found that numerical noises of the DNS are quickly enlarged to the same level as the‘true’physical solution,which finally destroy the spatial symmetry of the flow *** other words,the DNS results of the turbulent Kolmogorov flow governed by the NS equations are badly polluted *** the contrary,the numerical noise of the CNS is much smaller than the‘true’physical solution of turbulence in a long enough interval of time so that the CNS result is very close to the‘true’physical solution and thus can remain symmetric,which can be used as a benchmark solution for ***,it is found that numerical noise as a kind of artificial tiny disturbances can lead to huge deviations at large scale on the two-dimensional Kolmogorov turbulence governed by the NS equations,not only quantitatively(even in statistics)but also qualitatively(such as spatial symmetry of flow).This highly suggests that fine enough spatial grid spacing with small enough time-step alone could not guarantee the validity of the DNS of

关键词： Kolmogorov flow Statistical stability Computational reliability Clean numerical simulation Artificial numerical noises

Diagnostic Study of an Extreme Explosive Cyclone over the Kuroshio/Kuroshio Extension Region

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Journal of ocean University of China 2024年第3期23卷 605-617页

作者： ZHANG Shuqin LIAO Qinghua LIU Chunlei GAO Xiaoyu LONG Jingchao LI Pengyuan XU Jianjun College of ocean and Meteorology Guangdong Ocean UniversityZhanjiang 524088China South China Sea Institute of Marine Meteorology Guangdong Ocean UniversityZhanjiang 524088China CMA-GDOU Joint Laboratory for Marine Meteorology Guangdong Ocean UniversityZhanjiang 524088China Key Laboratory of Climate Resources and Environment in Continental Shelf Sea and Deep Sea of Department of Education of Guangdong ProvinceGuangdong Ocean UniversityZhanjiang 524088China state Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Department of Marine Meteorology Ocean-Atmosphere Interaction and Climate LaboratoryKey Laboratory of Physical OceanographyOcean University of ChinaQingdao 266100China

Explosive cyclones(ECs)occur frequently over the Kuroshio/Kuroshio Extension *** most rapidly intensified EC over the Kuroshio/Kuroshio Extension region during the 42 years(1979-2020)of cold seasons(October-April)was studied to reveal the variations of the key factors at different explosive-developing *** EC had weak low-level baroclinicity,mid-level cyclonic-vorticity advection,and strong low-level water vapor convergence at the initial explosive-developing *** low-level baroclinicity and mid-level cyclonic-vorticity advection increased substantially during the maximum-deepening-rate *** diagnostic analyses using the Zwack-Okossi equation showed that diabatic heating was the main contributor to the initial rapid intensification of this *** cyclonic-vorticity advection and warm-air advection enhanced rapidly in the middle and upper troposphere and contributed to the maximum rapid intensification,whereas the diabatic heating weakened slightly in the mid-low *** relative contribution of the diabatic heating decreased from the initial explosive-developing stage to the maximum-deepening-rate stage due to the enhancement of other factors(the cyclonic-vorticity advection and warm-air advection).Furthermore,the physical factors contributing to this EC varied with the explosive-developing *** non-key factors at the initial explosive-developing stage need attention to forecast the rapid intensification.

关键词： explosive cyclone diabatic heating cyclonic-vorticity advection rapid intensification the Kuroshio/Kuroshio Extension region

Characteristics of Particulate Matter Emissions for Low-Sulfur Heavy Oil Used in Low-Speed Two-Stroke Diesel Engines of ocean-Going Ships

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Journal of Thermal Science 2024年第2期33卷 739-750页

作者： WU Gang MA Qianli WEI Lijiang JIANG Guohe WANG Tengfei LI Tie Merchant Marine College Shanghai Maritime UniversityShanghai201306China state Key Laboratory of ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China

In this work,particulate matter(PM) emissions from a large two-stroke,low-speed marine diesel engine were investigated when the engine was operated with low-sulfur heavy fuel oil(HFO) at various *** samples were collected in situ from the engine exhaust to determine the detailed physical and chemical *** nanostructure and morphology of the nanoparticles were analyzed using transmission electron microscopy images(TEM).The results show that volatile organic carbon(OC) accounts for more than 80% in the HFO particles and leads to an increase in particle *** thermodynamic conditions of a low-speed engine favor the behavior of capturing the soluble organic components.A large number of spherical char HFO particles with aerodynamic diameters of 0.2 μm-0.5 μm and a suspected inner metal core were *** two peak aerodynamic diameters of the HFO nanoparticles are 15 nm and 86 *** morphological differences among the HFO nanoparticles in varied engine conditions represent the formation process from primary nascent particles to mature graphitized particles caused by *** above study will be valuable for understanding the characteristics of PM emissions from low-sulfur HFO to achieve the ship PM emissions reduction target.

关键词： low-speed diesel engine maritime regulations heavy fuel oil TEM particles size and distribution

Simultaneous enhancement of red luminescence and thermal stability of a novel red phosphor:A Li^(+)-Eu^(3+)co-occupied site strategy in BaAl_(2)Ge_(2)O_(8)lattices

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Journal of Rare Earths 2024年第10期42卷 1846-1854页

作者： Wei Zhang Changjian Wang Xusheng Qiao Xianping Fan state Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou310027China ocean Academy Zhejiang UniversityZhoushan316021China

The rapid development of phosphor-converted white light emitting diodes(pc-WLEDs)requires new red phosphors with efficient and thermally stable luminescence for high-quality warm-white ***,it is still a challenge to discover red phosphors with facile synthesis,high internal quantum efficiency(IQE),excellent thermal stability and high color ***,a novel red-emitting Eu^(3+)activated barium dialuminum digermanate(BaAl_(2)Ge_(3)O_(8),EAGO)phosphor showing strong red emission at 610 nm was *** IQE is improved from 32.91%to 78.84%by employing a charge compensation *** lithium-ion co-dop ed BAGO:Eu^(3+)phosphor exhibits a nearly twofold increase in integral photoluminescence(PL)intensity and the high color purity reaches 94.17%.Impressively,the PL intensity of the BAGO:Eu^(3+),Li^(+)phosphor drops by only 2.6%at 150℃of that at room ***,the pc-WLED using the red BAGO:Eu^(3+),Li^(+)phosphor exhibits white light with the chromaticity coordinate of(0.3515,0.3495),a high color-rendering index of 92 and a low correlated color temperature of 4746 *** these results manifest that BAGO:Eu^(3+),Li^(+)phosphor is a suitable red phosphor for nearultraviolet(NUV)chip-based pc-WLEDs.

关键词： BaAl_(2)Ge_(2)O_(8):Eu^(3+) Red phosphor Charge compensation High quantum efficiency Excellent thermal stability Rare earths

Noise‐tolerant matched filter scheme supplemented with neural dynamics algorithm for sea island extraction

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 996-1013页

作者： Yiyu Chen Dongyang Fu Difeng Wang Haoen Huang Yang Si Shangfeng Du School of Electronics and Information Engineering Guangdong Ocean UniversityZhanjiangChina state Key Laboratory of Satellite ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhouChina School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhanChina

Achieving high‐precision extraction of sea islands from high‐resolution satellite remote sensing images is crucial for effective resource development and sustainable ***,achieving such accuracy for sea island extraction presents significant challenges due to the presence of extensive background interference.A more widely applicable noise‐tolerant matched filter(NTMF)scheme is proposed for sea island extraction based on the MF *** NTMF scheme effectively suppresses the background interference,leading to more accurate and robust sea island *** further enhance the accuracy and robustness of the NTMF scheme,a neural dynamics algorithm is supplemented that adds an error integration feedback term to counter noise interference during internal computer operations in practical *** comparative experiments were conducted on various remote sensing images of sea islands under different noisy working conditions to demonstrate the superiority of the proposed neural dynamics algorithm‐assisted NTMF *** experiments confirm the ad-vantages of using the NTMF scheme for sea island extraction with the assistance of neural dynamics algorithm.

关键词： edge detection image classification image recognition shape extraction

Boron nitride silicone rubber composite foam with low dielectric and high thermal conductivity

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Chinese Journal of Chemical Engineering 2024年第4期68卷 224-230页

作者： Shuilai Qiu Hang Wu Fukai Chu Lei Song College of Safety and ocean Engineering China University of Petroleum-BeijingBeijing 102249China state Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230026China

Silicone rubber(SR)is widely used in the field of electronic packaging because of its low dielectric *** this work,the porosity of the SR was improved,and the dielectric constant of the SR foam was reduced by adding expanded microspheres(EM).Then,the thermal conductivity of the system was improved by combining the modified boron nitride(f-BN).The results showed that after the f-BN was added,the dielectric constant and dielectric loss were much lower than those of pure ***-sized modified boron nitride(f-mBN)improved the dielectric and thermal conductivity of the SR foam better than that of nano-sized modified boron nitride(f-nBN),but f-nBN improved the volume resistivity,tensile strength,and thermal stability of the SR better than *** the mass ratio of f-mBN and fnBN is 2:1,the thermal conductivity of the SR foam reaches the maximum value of 0.808 W·m^(-1)·K^(-1),which is 6.5 times that before the *** heat release rate and fire growth index are the lowest,and the improvement in flame retardancy is mainly attributed to the high thermal stability and physical barrier of f-BN.

关键词： Foam Composites Dielectric properties Thermal conductivity Mechanical properties Flame retardant

Experimental investigation on the permeability of gap-graded soil due to horizontal suffusion considering boundary effect

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 1072-1084页

作者： Xuwei Wang Yeshuang Xu state Key Laboratory of ocean Engineering School of Naval ArchitectureOceanand Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure Department of Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China

The boundary condition is a crucial factor affecting the permeability variation due to *** experimental investigation on the permeability of gap-graded soil due to horizontal suffusion considering the boundary effect is conducted,where the hydraulic head difference(DH)varies,and the boundary includes non-loss and soil-loss *** samples are filled into seven soil storerooms connected in *** evaluation,the variation in content of fine sand(ΔR_(f))and the hydraulic conductivity of soils in each storeroom(C_(i))are *** the non-loss test,the soil sample filling area is divided into runoff,transited,and accumulated areas according to the negative or positive ΔR_(f) values.ΔR_(f) increases from negative to positive along the seepage path,and Ci decreases from runoff area to transited area and then rebounds in accumulated *** the soil-loss test,all soil sample filling areas belong to the runoff area,where the gentle-loss,strengthened-loss,and alleviated-loss parts are further divided.ΔR_(f) decreases from the gentle-loss part to the strengthened-loss part and then rebounds in the alleviated-loss part,and C_(i) increases and then decreases along the seepage *** relationship between ΔR_(f) and Ci is different with the boundary *** exponentially decreases with ΔR_(f) in the non-loss test and increases with ΔR_(f) generally in the soil-loss test.

关键词： Suffusion Permeability Experimental investigation Boundary effect Horizontal seepage

Seasonal changes in gut microbiota of sea cucumber over natural aestivation cycle

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Journal of oceanology and Limnology 2024年第3期42卷 849-864页

作者： Ye ZHAO Han WANG Haona WANG Lijie ZHANG Hao SUN Yanying ZHANG ocean School Yantai UniversityYantai 264005China

Sea cucumber Apostichopus japonicus is an ideal model organism for marine invertebrate aestivation;it annually enters a“sleeping state”for nearly 3 months when ambient water temperature range is 25–30℃.The natural fasting is accompanied by remodeling the intestinal biota and function,which is a part of host biology and could affect the gut *** investigatesd the impact of annual aestivation on gut microbiota using high-throughput sequencing of 16S rRNA *** reveal a notable alteration in the composition of gut bacteria during aestivation during which various indigenous families and genera that exhibit a preference for dietary glycans(e.g.,family Rhodobacteraceae and Flavobacteriaceae)decreased,while the taxa capable of utilizing substrates derived from the host(e.g.,genus Akkermansia and Prevotella)increased,and so did certain opportunistic pathogenic ***,the investigation delved into the gut morphology and immunity response of *** and reveal that the intestine of *** undergoes substantial atrophy and degeneration during ***,there was an observed augmentation in the levels of acid and neutral mucin within mucous cells,as well as an enhanced immune defense response(as evidenced by increased gene expression of AjTLR3,LITAF,Ajp105,and LYZ).These results imply that the composition of sea cucumber gut microbiota differed between aestivation and active periods,which potentially affects the intestinal functions of the host and the symbiotic relationship between host and its microbiota over the activeaestivation cycle.

关键词： Apostichopus japonicus aestivation gut microbiota diet Illumina sequencing