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Geochemical evaluation of low salinity hot water injection to enhance heavy oil recovery from carbonate reservoirs

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Petroleum Science 2019年第2期16卷 366-381页

作者： Ji Ho lee kun sang lee Department of Earth Resources and Environmental Engineering Hanyang University

Although low salinity water injection(LSWI) has recovered residual oil after the conventional waterflood, highly viscous oil has remained in heavy oil reservoirs. Hot water injection is an economic and practical method to improve oil mobility for viscous oil reservoirs. It potentially controls temperature-dependent geochemical reactions underlying the LSWI mechanism and oil viscosity. Therefore, this study has modeled and evaluated a hybrid process of low salinity hot water injection(hot LSWI) to quantify synergistic effects in heavy oil reservoirs. In comparison to seawater injection(SWI) and LSWI, hot LSWI results in more cation ion-exchange(Ca^(2+) and Mg^(2+)) and more wettability modification. Hot LSWI also reduces oil viscosity. In core-scaled systems, it increases oil recovery by 21% and 6% over SWI and LSWI. In a pilotscaled reservoir, it produces additional oil by 6% and 3% over SWI and LSWI. Probabilistic forecasting with uncertainty assessment further evaluates the feasibility of hot LSWI to consider uncertainty in the pilot-scaled reservoir and observes enhanced heavy oil production. This study confirms the viability of hot LSWI due to synergistic effects including enhanced wettability modification and oil viscosity reduction effects.

关键词： Low salinity water injection Hot water injection Wettability modification Geochemical reaction Viscosity reduction

Controlled oxidation of Ni for stress-free hole transport layer of large-scale perovskite solar cells

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Nano Research 2019年第12期12卷 3089-3094页

作者： Seongha lee Hee-Suk Roh Gill sang Han Jung-kun lee Department of Mechanical Engineering and Materials Science University of PittsburghPennsylvania 15261USA School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea

The effect of the residual thermal stress of NiO films on the performance of an inverted type perovskite solar cell was *** this study,NiO films were grown on fluorine dopedtin oxide(FTO)substrates of different surface roughness by thermally oxidizing Ni film and weretested as a hole transport layer for large-scale perovskite solar *** and simulation results show that it is very important tosuppress the appearance of the residual stress at the NiO-FTO in terface during the oxidation of the Ni film for effective hole extracti *** Ni oxidation on the flat FTO film produced in-plane compressive stress in the NiO film due to the Ni film volume *** led to theformation of defects including small *** residual stress and defects in creased leakage curre nt through the NiO film,preve ntingholes from being selectively collected at the NiO-perovskite ***,when Ni was deposited and oxidized on the rough surface,the residual stress of the NiO film was negligible and its inhere nt high resistance was ***-free NiO film is an excelle nt holetransport layer that stops the photogenerated electrons of the perovskite layer from moving to *** improvements in the structural andelectrical qualities of the NiO film by engirteering the residual stress reduce the carrier recombination and increase the power conversi onefficiency of the perovskite solar cells to 16.37%.

关键词： nickel oxidation surface roughness residual stress perovskite solar cells large scale processing

Compositional modeling and simulation of dimethyl ether (DME)-enhanced waterflood to investigate oil mobility improvement

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Petroleum Science 2018年第2期15卷 297-304页

作者： Jinhyung Cho Tae Hong Kim kun sang lee Department of Earth Resources and Environmental Engineering Hanyang University

Dimethyl ether （DME） is a widely used industrial compound, and Shell developed a chemical EOR technique called DME- enhanced waterflood （DEW）. DME is applied as a miscible solvent for EOR application to enhance the performance of conventional waterflood. When DME is injected into the reservoir and contacts the oil, the first-contact miscibility process occurs, which leads to oil swelling and viscosity reduction. The reduction in oil density and viscosity improves oil mobility and reduces residual oil saturation, enhancing oil production. A numerical study based on compositional simulation has been developed to describe the phase behavior in the DEW model. An accurate compositional model is imperative because DME has a unique advantage of solubility in both oil and water. For DEW, oil recovery increased by 34% and 12% compared to conventional waterflood and CO2 flood, respectively. Compositional modeling and simulation of the DEW process indicated the unique solubility effect of DME on EOR performance.

关键词： Dimethyl ether (DME) DME-enhanced waterflood (DEW) Solubility Oil mobility

Phylogenetic diversity of planktonic bacteria in the Chukchi Borderland region in summer

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Acta Oceanologica Sinica 2013年第6期32卷 66-74页

作者： ZENG Yinxin YU Yong LI Huirong HE Jianfeng lee sang H SUN kun Key Laboratory for Polar Science of State Oceanic Administration Polar Research Institute of China College of Biological Engineering Jimei University Department of Oceanography Pusan National University

Planktonic bacteria are abundant in the Chukchi Borderland region. However, little is known about their di- versity and the roles of various bacteria in the ocean. Seawater samples were collected from two stations K2S and K4S where sea ice was melting obviously. The analysis of water samples with fluorescence in situ hybridization （FISH） showed that DMSP-degrading bacteria accounted for 13% of the total bacteria at the station K2S. No aerobic anoxygenic phototrophic （AAP） bacteria were detected in both samples. The bacterial communities were characterized by two 16S rRNA gene clone libraries. Sequences fell into four major lineages of the domain Bacteria, including Proteobacteria （Alpha, Beta and Gamma subclasses）, Bac- teroidetes, Actinobacteria and Firmicutes. No significant difference was found between the two clone li- braries. SAR11 and Rhodobacteraceae clades of Alphaproteobacteria and Pseudoalteromonas of Gammapro- teobacteria constituted three dominant fractions in the clone libraries. A total of 191 heterotrophic bacterial strains were isolated and 76% showed extracellular proteolytic activity. Phylogenetic analysis reveals that the isolates fell into Gammaproteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. The most common genus in both the bacterial isolates and protease-producing bacteria was Pseudoalteromonas. UniFrac data showed suggestive differences in bacterial communities between the Chukchi Borderland and the northern Bering Sea.

关键词： diversity planktonic bacteria 16S rRNA gene clone library Chukchi Borderland

Dual function of a high-contrast hydrophobic-hydrophilic coating for enhanced stability of perovskite solar cells in extremely humid environments

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Nano Research 2017年第11期10卷 3885-3895页

作者： Jin Sun Yoo Gill sang Han Seongha lee Min Cheol Kim Mansoo Choi Hyun Suk Jung Jung-kun lee School of Advanced Materials Science amp Engineering Sungkyunkwan University Suwon 440-746 Republic of Korea Department of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh Pennsylvania 15261 USA Department of Mechanical and Aerospace Engineering Seoul National University Seoul 08826 Republic of Korea

In spite of a continuous increase in their power conversion efficiency （PCE） and an economically viable fabrication process,organic-inorganic perovskite solar cells （PSCs） pose a significant problem when used in practical applications：They show fast degradation of the PCE when exposed to very humid *** this study,the stability of PSCs under very humid conditions is greatly enhanced by coating the surface of the PSC devices with a multi-layer film consisting of ultrahydrophobic and relatively hydrophilic layers.A hydrophobic composite of poly（methyl methacrylate）（PMMA）,polyurethane （PU）,and SiO2 nanoparticles successfully retards the water molecules from very humid ***,the hydrophilic layer with moderately PMMA captures the residual moisture within the perovskite layer;subsequently,the perovskite layer *** dual function of the coating film keeps the PCE of PSCs at 17.3% for 180 min when exposed to over 95% humidity.

关键词： perovskite solar cell stability surface coating ultrahydrophobic self-recovery

ZnO-Embedded Expanded Graphite Composite Anodes with Controlled Charge Storage Mechanism Enabling Operation of Lithium-Ion Batteries at Ultra-Low Temperatures

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Energy & Environmental Materials 2023年第4期6卷 31-39页

作者： kun Ryu Michael J.lee Kyungbin lee Seung Woo lee George W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

As lithium(Li)-ion batteries expand their applications,operating over a wide temperature range becomes increasingly ***,the lowtemperature performance of conventional graphite anodes is severely hampered by the poor diffusion kinetics of Li ions(Li^(+)).Here,zinc oxide(ZnO) nanoparticles are incorporated into the expanded graphite to improve Li^(+)diffusion kinetics,resulting in a significant improvement in lowtemperature *** ZnO-embedded expanded graphite anodes are investigated with different amounts of ZnO to establish the structurecharge storage mechanism-performance relationship with a focus on lowtemperature *** analysis reveals that the ZnOembedded expanded graphite anode with nano-sized ZnO maintains a large portion of the diffusion-controlled charge storage mechanism at an ultra-low temperature of-50℃ Due to this significantly enhanced Li^(+)diffusion rate,a full cell with the ZnO-embedded expanded graphite anode and a LiNi_(0.88)Co_(0.09)Al_(0.03)O_(2)cathode delivers high capacities of 176 mAh g^(-1)at20℃ and 86 mAh g^(-1)at-50℃ at a high rate of 1 *** outstanding low-temperature performance of the composite anode by improving the Li^(+)diffusion kinetics provides important scientific insights into the fundamental design principles of anodes for low-temperature Li-ion battery operation.

关键词： diffusive and capacitive charge storages expanded graphite composites anode lithium-ion battery low-temperature operation transition metal oxide

Epoxy resin nanocomposites reinforced with ionized liquid stabilized carbon nanotubes

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International Journal of Smart and Nano Materials 2011年第3期2卷 176-193页

作者： Zhe Wang Xiongtao Yang Qiang Wang H.Thomas Hahn sang-gi lee kun-Hong lee Zhanhu Guo Mechanical&Aerospace Engineering Department University of California Los AngelesLos AngelesCA 90095USA Integrated Composites Lab Dan F.Smith Department of Chemical EngineeringLamar UniversityBeaumontTX 77710USA Institute of Chemical and Engineering Sciences(ICES) A-STARApplied Catalysis1Pesek RoadJurong Island627833 Singapore Department of Chemistry and Nano Science Ewha Womans UniversitySeoul 120-750Korea Department of Chemical Engineering Pohang University of Science and TechnologyPohang 790-784Korea

Epoxy resin nanocomposites reinforced with three different ionic liquid functionalized carbon nanotubes(f-CNTs)were fabricated by an in situ polymerization *** influence of the anions on the curing process was studied through differential scanning calorimetry(DSC)and normalized Fourier transform infrared(FTIR)*** composition of the nanocomposites was analyzed by X-ray photoelectron *** different mechanisms are proposed to explain the curing process of the neat epoxy and its *** electric conductivity and mechanical properties of the nanocomposites are also *** tensile strength was increased dramatically due to the insertion of *** electron microsopy fracture surface analysis indicates a strong interfacial bonding between the carbon nanotubes and the polymer matrix.

关键词： epoxy resin nanocomposite carbon nanotube ionic liquid functionalization

Epidemic obesity in children and adolescents:risk factors and prevention

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Frontiers of Medicine 2018年第6期12卷 658-666页

作者： Eun Young lee kun-Ho Yoon Division of Endocrinology and Metabolism Department of Internal MedicineSeoul St.Mary's HospitalCollege of MedicineThe Catholic University of KoreaSeoul 06591Korea Institute of Catholic Ubiquitous Health Care The Catholic University of KoreaSeoul 06591Korea

The prevalence of obesity among children and adolescents (aged 2-18 years) has increased rapidly, with more than 100 million affected in 2015. Moreover, the epidemic of obesity in this population has been an important public health problem in developed and developing countries for the following reasons. Childhood and adolescent obesity tracks adulthood obesity and has been implicated in many chronic diseases, including type 2 diabetes, hypertension, and cardiovascular disease. Furthermore, childhood and adolescent obesity is linked to adulthood mortality and premature death. Although an imbalance between caloric intake and physical activity is a principal cause of childhood and adolescent obesity, environmental factors are exclusively important for development of obesity among children and adolescents. In addition to genetic and biological factors, socioenvironmental factors, including family, school, community, and national policies, can play a crucial role. The complexity of risk factors for developing obesity among children and adolescents leads to difficulty in treatment for this population. Many interventional trials for childhood and adolescent obesity have been proven ineffective. Therefore, early identification and prevention is the key to control the global epidemic of obesity. Given that the proportion of overweight children and adolescents is far greater than that of obesity, an effective prevention strategy is to focus on overweight youth, who are at high risk for developing obesity. Multifaceted, comprehensive strategies involving behavioral, psychological, and environmental risk factors must also be developed to prevent obesity among children and adolescents.

关键词： adolescents children epidemiology obesity prevention risk factor

A NEW BOUNDARY CONDITION FOR RATE-TYPE NON-NEWTONIAN DIFFUSIVE MODELS AND THE STABLE MAC SCHEME

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Journal of Computational Mathematics 2018年第4期36卷 605-626页

作者： kun Li Youngju lee Christina Starkey BGP R&D Center CNPC Beijing 100871 China Department of Mathematics Texas State University San Marcos TX 78666 USA

We present a new Dirichlet boundary condition for the rate-type non-Newtonian diffusive constitutive models. The newly proposed boundary condition is compared with two such well-known and popularly used boundary conditions as the pure Neumann condition and the Dirichlet condition by Sureshkumar and Beris. Our condition is demonstrated to be more stable and robust in a number of numerical test cases. A new Dirichlet boundary condition is implemented in the framework of the finite difference Marker and Cell （MAC） method. In this paper, we also present an energy-stable finite difference MAC scheme that preserves the positivity for the conformation tensor and show how the addition of the diffusion helps the energy-stability in a finite difference MAC scheme-setting.

关键词： Boundary Conditions Diffusive Complex Fluids models Positivity preserving schemes Stability of the MAC schemes