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Numerical analysis of the hydraulic fracture communication modes in fracture-cavity reservoirs

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Petroleum Science 2022年第5期19卷 2227-2239页

作者： jia-wei Kao Shi-Ming wei Wen-Zhi Wang Yan jin State Key Laboratory Petroleum Resources and Prospecting China University of PetroleumBeijing102249China Sinopec Research Institute of Petroleum Engineering Beijing102206China CNPC Engineering Technology R&D Company Limited Beijing102206China

The fracture-cavity carbonate reservoirs in the Tahe Oilfield in China are mainly exploited by fracturing.We need the hydraulic fractures to communicate with caves to create a flow channel.However,due to the existence of the fracture-cavity systems,the hydraulic fracture propagation morphology is complicated,while the propagation characteristics are not clear.To analyze the hydraulic fracture propagation in fracture-cavity carbonate formations,based on the discontinuous discrete fracture model,we developed a solid-seepage-freeflow coupled fracturing model for fracture-cavity formations,which can simulate the complex interaction behavior of fractures and caves.Based on the simulation results,we found the interaction rule between hydraulic fractures and fracture-cavity systems:the stress concentration around caves is the main factor that determines the fracture propagation path.Deflection due to stress concentration is usually not conducive to communication,while natural fractures distributed around caves could break the rejection action.Increasing the hydraulic energy in the hydraulic fracture can make fracture propagate directly and reduce the influence of deflection.The steering fracture formed by temporary plugging is beneficial to the communication of fracture-cavity systems in the non-principal stress direction.According to the simulation results of different fracture-cavity characteristics,we raised four optimization communication modes for fracture-cavity carbonate formation to provide references for fracturing optimization design and parameter optimization.

关键词： Fracture-cavity carbonate formation Hydraulic fracture propagation Numerical simulation Fracture-cave communication Discontinuous discrete fracture model

Nitrogen in plants:from nutrition to the modulation of abiotic stress adaptation

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Stress Biology 2022年第1期2卷 647-660页

作者： jia Yuan Ye Wen Hao Tian Chong wei jin State Key Laboratory of Plant Physiology and Biochemistry College of Natural Resources and Environmental ScienceZhejiang UniversityHangzhou 310058China State Key Laboratory of Rice Biology China National Rice Research InstituteZhejiang 310006HangzhouChina

Nitrogen is one of the most important nutrient for plant growth and development;it is strongly associated with a variety of abiotic stress responses.As sessile organisms,plants have evolved to develop efficient strategies to manage N to support growth when exposed to a diverse range of stressors.This review summarizes the recent progress in the field of plant nitrate(NO3-)and ammonium(NH4+)uptake,which are the two major forms of N that are absorbed by plants.We explore the intricate relationship between NO3-/NH4+and abiotic stress responses in plants,focusing on stresses from nutrient deficiencies,unfavorable pH,ions,and drought.Although many molecular details remain unclear,research has revealed a number of core signaling regulators that are associated with N-mediated abiotic stress responses.An in-depth understanding and exploration of the molecular processes that underpin the interactions between N and abiotic stresses is useful in the design of effective strategies to improve crop growth,development,and productivity.

关键词： Nitrate Ammonium Uptake Signaling Abiotic stress

Hydraulic directional valve fault diagnosis using a weighted adaptive fusion of multi-dimensional features of a multi-sensor

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第4期23卷 257-271页

作者： jin-chuan SHI Yan REN He-sheng TANG jia-wei XIANG College of Mechanical and Electrical Engineering Wenzhou UniversityWenzhou325035China

Because the hydraulic directional valve usually works in a bad working environment and is disturbed by multi-factor noise,the traditional single sensor monitoring technology is difficult to use for an accurate diagnosis of it.Therefore,a fault diagnosis method based on multi-sensor information fusion is proposed in this paper to reduce the inaccuracy and uncertainty of traditional single sensor information diagnosis technology and to realize accurate monitoring for the location or diagnosis of early faults in such valves in noisy environments.Firstly,the statistical features of signals collected by the multi-sensor are extracted and the depth features are obtained by a convolutional neural network(CNN)to form a complete and stable multi-dimensional feature set.Secondly,to obtain a weighted multi-dimensional feature set,the multi-dimensional feature sets of similar sensors are combined,and the entropy weight method is used to weight these features to reduce the interference of insensitive features.Finally,the attention mechanism is introduced to improve the dual-channel CNN,which is used to adaptively fuse the weighted multi-dimensional feature sets of heterogeneous sensors,to flexibly select heterogeneous sensor information so as to achieve an accurate diagnosis.Experimental results show that the weighted multi-dimensional feature set obtained by the proposed method has a high fault-representation ability and low information redundancy.It can diagnose simultaneously internal wear faults of the hydraulic directional valve and electromagnetic faults of actuators that are difficult to diagnose by traditional methods.This proposed method can achieve high fault-diagnosis accuracy under severe working conditions.

关键词： Hydraulic directional valve Internal fault diagnosis weighted multi-dimensional features Multi-sensor information fusion

Experimental study of wave propagation characteristics on a simplified coral reef

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Journal of Hydrodynamics 2020年第2期32卷 385-397页

作者： jia-yi Xu Shu-xue Liu jin-xuan Li wei jia State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian116024China

The wave transformation over slope topography is widely studied,but most of studies are for common coastal slopes.This paper presents an experimental study of 2-D regular and irregular wave transformations on a simplified coral reef with a steep slope of 1:5 and a horizontal reef flat,focusing on the characteristics of the waves that break on the reef flat.The analyzed results show that the estimates of the wave breaking made by using the well-known previous formulae do not agree completely with the experimental results.When the waves break on a reef flat,the relative breaking wave height(H/d)b is related to the incident deep-water wave steepness and the relative water depth db/L0.Hence,a new criterion for breaking waves on a reef flat is proposed.Furthermore,in view of the fact that the local Ursell number is commonly used to parameterize the wave nonlinearity,the relationships among the skewness,the asymmetry,and the local Ursell number are also presented.Experimental data confirm that when the Ursell number is greater than 30,the absolute values of the skewness and the asymmetry on a reef flat are greater than those on a steep slope.

关键词： Coral reef bathymetry wave breaking wave height attenuation representative wave parameter nonlinear parameters

CuS nanoenzyme against bacterial infection by in situ hydroxyl radical generation on bacteria surface

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Rare Metals 2023年第6期42卷 1899-1911页

作者： Zhao Li Cheng-jia Xie Xiao-wei Ren Qun Zhang Bao-jin Ma Department of Tissue Engineering and Regeneration School and Hospital of StomatologyCheeloo College of MedicineShandong University&Shandong Key Laboratory of Oral Tissue Regeneration&Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration&Shandong Provincial Clinical Research Center for Oral DiseasesJinan250012China jinan Food and Drug Inspection and Testing Center Jinan250010China

Nanoenzyme-mediated antibacterial strategies have been widely exploited to overcome the shortcomings(such as drug resistance and mild-to-severe side effects) of antibiotic therapy.The peroxidase-like activity of nanoenzymes possesses great potential against bacterial infection by the generation of hydroxyl radical(·OH) in the specific microenvironment.However,the lifetime of-OH is extremely short,and a large amount of the ·OH generated within the infection microenvironment cannot come into contact with bacteria quickly enough,thus resulting in low treatment efficiency.Here,chitosan-oligosaccharide-modified CuS nanoparticles possessing positive charges(PCuS NPs) were prepared using a one-pot method.PCuS NPs exhibited efficient peroxidase-like activity.Importantly,the PCuS NPs can combine with bacteria via electrostatic attraction.The direct contact between the PCuS NPs and bacteria enabled the generation of ·OH in situ on the bacterial surface,ultimately leading to a high antibacterial efficacy at a low concentration in the presence of H_(2)O_(2).At an effective antibacterial concentration,the PCuS NPs exhibited high cytocompatibility.Furthermore,in vivo results revealed that PCuS NPs not only decreased the size of abscesses but also reduced inflammation and promoted collagen fiber formation.Therefore,PCuS NPs possess great potential against bacterial infection via in situ ·OH generation based on electrostatic attraction.

关键词： Antibacterial CuS Nanoenzyme In situ ·OH generation Electrostatic attraction

Meta-analysis with zero-event studies:a comparative study with application to COVID-19 data

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Military Medical Research 2022年第1期9卷 126-137页

作者： Jia-Jin Wei En-Xuan Lin jian-Dong Shi Ke Yang Zong-Liang Hu Xian-Tao Zeng Tie-Jun Tong department of Mathematics Hong Kong Baptist UniversityHong KongChina Shenzhen Research Institute of Big Data ShenzhenChina College of Mathematics and Statistics Shenzhen UniversityShenzhenChina Center for Evidence-Based and Translational Medicine Zhongnan Hospital of Wuhan UniversityWuhanChina.

Background:Meta-analysis is a statistical method to synthesize evidence from a number of independent studies,including those from clinical studies with binary outcomes.In practice,when there are zero events in one or both groups,it may cause statistical problems in the subsequent analysis.Methods:In this paper,by considering the relative risk as the effect size,we conduct a comparative study that consists of four continuity correction methods and another state-of-the-art method without the continuity correction,namely the generalized linear mixed models(GLMMs).To further advance the literature,we also introduce a new method of the continuity correction for estimating the relative risk.Results:From the simulation studies,the new method performs well in terms of mean squared error when there are few studies.In contrast,the generalized linear mixed model performs the best when the number of studies is large.In addition,by reanalyzing recent coronavirus disease 2019(COVID-19)data,it is evident that the double-zero-event studies impact the estimate of the mean effect size.Conclusions:We recommend the new method to handle the zero-event studies when there are few studies in a meta-analysis,or instead use the GLMM when the number of studies is large.The double-zero-event studies may be informative,and so we suggest not excluding them.

关键词： Continuity correction Coronavirus disease 2019 data Meta-analysis Relative risk Zero-event studies

Static and dynamic evolution of CO adsorption onγ-U(100)surface with different levels of Mo doping using DFT and AIMD calculations

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Nuclear Science and Techniques 2023年第9期34卷 142-154页

作者： Jun-wei Li wei-Min jia Chong Liu Sha-Sha Lv jin-Tao Wang Zheng-Cao Li Key Lab of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Xi’an Research Institute of High-Technology Xi’an 710025China Key Laboratory of Beam Technology(MOE) College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China

Alloys of uranium and molybdenum are considered as the future of nuclear fuel and defense materials.However,surface corrosion is a fundamental problem in practical applications and storage.In this study,the static and dynamic evolution of carbon monoxide(CO)adsorption and dissociation onγ-U(100)surface with different Mo doping levels was investigated based on density functional theory and ab initio molecular dynamics.During the static calculation phase,parameters,such as adsorption energy,configuration,and Bader charge,were evaluated at all adsorption sites.Furthermore,the time-dependent behavior of CO molecule adsorption were investigated at the most favorable sites.The minimum energy paths for CO molecu-lar dissociation and atom migration were investigated using the transition state search method.The results demonstrated that the CO on the uranium surface mainly manifests as chemical adsorption before dissociation of the CO molecule.The CO molecule exhibited a tendency to rotate and tilt upright adsorption.However,it is difficult for CO adsorption on the surface in one of the configurations with CO molecule in vertical direction but oxygen(O)is closer to the surface.Bader charge illustrates that the charge transfers from slab atoms to the 2π*antibonding orbital of CO molecule and particularly occurs in carbon(C)atoms.The time is less than 100 fs for the adsorptions that forms embryos with tilt upright in dynamics evolution.The density of states elucidates that the overlapping hybridization of C and O 2p orbitals is mainly formed via the d orbitals of uranium and molybdenum(Mo)atoms in the dissociation and re-adsorption of CO molecule.In conclusion,Mo doping of the surface can decelerate the adsorption and dissociation of CO molecules.A Mo-doped surface,created through ion injection,enhanced the resistance to uranium-induced surface corrosion.

关键词： Adsorption and dissociation Uranium CO molecule Density functional theory Ab initio molecular dynamics

Hepatic perivascular epithelioid cell tumors:The importance of preoperative diagnosis

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World Journal of Gastroenterology 2024年第13期30卷 1926-1933页

作者： Shuai Yan jia-Jie Lu Lin Chen wei-Hua Cai jin-Zhu Wu Department of Medical School Nantong UniversityNantong 226300Jiangsu ProvinceChina Department of Hepatobiliary Surgery Affiliated Nantong Hospital 3 of Nantong UniversityNantong 226006Jiangsu ProvinceChina Nantong Institute of Liver Disease Affiliated Nantong Hospital 3 of Nantong UniversityNantong 226006Jiangsu ProvinceChina

Accurate preoperative diagnosis is highly important for the treatment of perivascular epithelioid cell tumors(PEComas)because PEComas are mainly benign tumors and may not require surgical intervention.By analyzing the causes,properties and clinical manifestations of PEComas,we summarize the challenges and solutions in the diagnosis of PEComas.

关键词： Hepatic perivascular epithelioid cell tumors Liver Preoperative diagnosis Angiomyolipomas Mesenchymal tissue-derived tumors

Design and friction loss study of full-ocean depth oil-filled direct current motor

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第8期23卷 587-598页

作者： Hao WANG Chen CAO jin GUO wei WANG Peng ZHOU jia-wang CHEN Ocean College Zhejiang UniversityZhoushan 316000China

In this study,we designed an oil-filled motor that can be used at full-ocean depths,and investigated the friction losses caused by the rotating seal and the properties of the oil.The direct current(DC)motor is encapsulated in an aluminum alloy housing.A rubber diaphragm is used to balance the internal and external pressures so that the motor can work on the seabed without pressure difference.To study the resistance caused by the rotating seal,a numerical model of the Glyd ring and the rotating shaft was established.Results from a rotational torque test agreed with those from numerical analysis.The kinematic viscosity of four oils was measured at 1-25℃.Oil bath experiments in an incubator showed that the resistance from oil is highly correlated with its dynamic viscosity.Dimethicone appears to be very suitable as an insulating oil for these motors.The working characteristics of the motor were tested in a high-pressure chamber.The results showed that the motor needs to overcome higher oil resistance under higher pressure.A prototype of a pressure-adaptive motor was designed and applied successfully in the hadal zone at a water depth of more than 10000 m.

关键词： Oil-filled motor Full-ocean depth Rotating seals Friction loss Viscous power Sea trial