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Multiple damage zones around hydraulic fractures generated by high-frequency pulsating hydraulic fracturing

Petroleum Science 2024年第4期21卷 2688-2702页

作者： Yan Peng Sheng-Jie wei Guang-Qing Zhang da.wei zhou Chuang-Chao Xu School of Petroleum Engineering China University of Petroleum PetroChina Changqing Oilfield Company

Pulsating hydraulic fracturing(PHF) is a promising fracturing method and can generate a dynamic periodic pressure. The periodic pressure can induce fatigue failure of rocks and decrease initiation pressure of fracture. If the frequency of periodic pressure exceeds 10 Hz, the distribution of pressure along the main fracture will be heterogeneous, which is much different from the one induced by the common fracturing method. In this study, the impact of this special spatial feature of pressure on hydraulic fracture is mainly investigated. A coupled numerical simulation model is first proposed and verified through experimental and theoretical solutions. The mechanism of secondary fracture initiation around the main fracture is then discovered. In addition, sensitivity studies are conducted to find out the application potential of this new method. The results show that(1) this coupled numerical simulation model is accurate. Through comparison with experimental and theoretical data, the average error of this coupled model is less than 1.01%.(2) Even if a reservoir has no natural fracture, this heterogeneous distribution pressure can also cause many secondary fractures around the main fracture.(3) The mechanism of secondary fracture initiation is that this heterogeneous distribution pressure causes tensile stress at many locations along the main fracture.(4) Through adjusting the stimulation parameters, the stimulation efficiency can be improved. The average and amplitude of pressure can increase possibility of secondary fracture initiation. The frequency of this periodic pressure can increase number of secondary fractures. Even 6 secondary fractures along a 100 m-length main fracture can be generated.(5) The influence magnitudes of stimulation parameters are larger than ones of geomechanical properties, therefore, this new fracturing method has a wide application potential.

关键词： Tight reservoir Reservoir stimulation Numerical simulation Secondary fracture Fracture initiation

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Therapeutic utility of human umbilical cord-derived mesenchymal stem cells-based approaches in pulmonary diseases:Recent advancements and prospects

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World Journal of Stem Cells 2024年第2期16卷 70-88页

作者： Min Meng wei-wei Zhang Shuang-Feng Chen da-Rui Wang Chang-Hui zhou Department of Central Laboratory Liaocheng People’s HospitalLiaocheng 252000Shandong ProvinceChina Department of Clinical Laboratory Liaocheng People’s HospitalLiaocheng 252000Shandong ProvinceChina

Pulmonary diseases across all ages threaten millions of people and have emerged as one of the major public health issues *** diverse disease con-ditions,the currently available approaches are focused on alleviating clinical symptoms and delaying disease progression but have not shown significant therapeutic effects in patients with lung *** umbilical cord-derived mesenchymal stem cells(UC-MSCs)isolated from the human UC have the capacity for self-renewal and multilineage ***,in recent years,these cells have been demonstrated to have unique advantages in the treatment of lung *** searched the Public Clinical Trial database and found 55 clinical trials involving UC-MSC therapy for pulmonary diseases,including coronavirus disease 2019,acute respiratory distress syndrome,bron-chopulmonary dysplasia,chronic obstructive pulmonary disease,and pulmonary *** this review,we summarize the characteristics of these registered clinical trials and relevant published results and explore in depth the challenges and opportunitiesfaced in clinical ***,the underlying mole-cular mechanisms involved in UC-MSC-based therapy for pulmonary diseases are also analyzed in *** brief,this comprehensive review and detailed analysis of these clinical trials can be expected to provide a scientific reference for future large-scale clinical application.

关键词： Pulmonary diseases Mesenchymal stem cells Human umbilical cord Cell therapy Clinical trials

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Phase field modeling of ferroelastic variant switching in yttria-stabilized t'zirconia with strain gradient elasticity and interface tension

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Science China(Technological Sciences) 2024年第5期67卷 1443-1457页

作者： zhou QianQian wei YueGuang zhou YiChun YANG Li College of Engineering BIC-ESATPeking UniversityBeijing100871China School of Advanced Materials and Nanotechnology Xidian UniversityXi’an710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an710126China

The 6–8 wt%yttria-stabilized zirconia with a tetragonal structure(t’-YSZ)is extensively employed in thermal barrier *** exceptional fracture toughness of t’-YSZ can be attributed to its distinctive ferroelastic toughening *** and interface tension play a critical role in ferroelastic variant switching at the micro-and *** paper presents an original thermodynamically consistent phase field(PF)theory for analyzing ferroelastic variant switching at the micro-and nano-scale of t’-*** theory incorporates strain gradient elasticity using higher-order elastic energy and interface tension tensor via geometric nonlinearity to represent biaxial tension resulting from interface ***,a mixed-type formulation is employed to implement the higher-order theory through the finite element *** an interface in equilibrium,the effects of strain gradient elasticity result in a more uniform distribution of stresses,whereas the presence of interface tension tensor significantly amplifies the stress magnitude at the *** introduction of an interface tension tensor increases the maximum value of stress at the interface by a factor of 4 to *** nucleation and evolution of variants at a pre-existing crack tip in a mono-phase t’-YSZ have also been *** strain gradient elasticity is capable of capturing the size effect of ferroelastic variant switching associated with microstructures in ***,when the grain size approaches that of the specimen,the critical load required for variant switching at the crack tip increases,resulting in greater dissipation of elastic energy during ferroelastic variant ***,the interface tension accelerates the evolution of *** presented framework exhibits significant potential in modeling ferroelastic variant switching at the micro-and nano-scale.

关键词： thermodynamics strain gradient elasticity interface tension phase field method ferroelastic variant switching

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2D all-organic perovskites refine flexible electronics

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Science China Materials 2024年第7期67卷 2365-2366页

作者： wei zhou Bing Chen College of Electronic and Optical Engineering and College of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Recent years have witnessed a paradigm shift with the advent of perovskites,a class of materials with a distinct CaTiO_(3)-type crystalline structure that show remarkable promise across a wide array of applications,including photovoltaics,photodetectors,lighting,lasers,and so *** them,the development of two-dimensional(2D)perovskites has garnered significant attention due to their tunable structures(mainly Dion-Jacobson and Ruddlesden-Popper structures)and enhanced stability in comparison with their 3D counterparts[1].Amidst the burgeoning research on perovskites,on the other side,all-organic perovskites stand out as a particularly intriguing subset[2].Unlike traditional perovskites that typically comprise all-inorganic(e.g.,CsPbBr_(3))or organic-inorganic hybrid components(e.g.,(PEA)_(2)PbI_(4)),all-organic perovskites are composed entirely of carbon-or nitrogen-based molecules.

关键词： perovskite inorganic entirely

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Local Hamilton type Gradient Estimates and Harnack Inequalities for Nonlinear Parabolic Equations on Riemannian Manifolds

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 539-546页

作者： Wen WANG da-peng XIE Hui zhou School of Mathematics and Statistics Hefei Normal UniversityHefei 230601China

In this paper,we prove a local Hamilton type gradient estimate for positive solution of the nonlinear parabolic equation ut(x,t)=Δu(x,t)+au(x,t) ln u(x,t)+bu^(α)(x,t),on M×(-∞,∞) with α∈R,where a and b are *** ... 详细信息

关键词： nonlinear parabolic equation gradient estimate Harnack inequality

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Analysis of cancer-specific survival in patients with metastatic colorectal cancer: A evidence-based medicine study

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World Journal of Gastrointestinal Surgery 2024年第6期16卷 1791-1802页

作者： Yin-Jie zhou Zhi-E Tan wei-da Zhuang Xin-Hua Xu Department of Oncology The First College of Clinical Medical ScienceChina Three Gorges University&Yichang Central People's HospitalYichang 443000Hubei ProvinceChina Department of Nuclear Medicine The First College of Clinical Medical ScienceChina Three Gorges University&Yichang Central People's HospitalYichang 443000Hubei ProvinceChina Department of Athe and Intestinal Surgery Cancer Hospital of The Chinese Academy of Medical SciencesBeijing 100021China

BACKGROUND Metastatic colorectal cancer(mCRC)is a common malignancy whose treatment has been a clinical ***-specific survival(CSS)plays a crucial role in assessing patient prognosis and treatment ***,there is still li-mited research on the factors affecting CSS in mCRC patients and their *** To predict CSS,we developed a new nomogram model and risk grading system to classify risk levels in patients with *** data were extracted from the United States Surveillance,Epidemiology,and End Results database from 2018 to *** eligible patients were randomly divided into a training cohort and a validation *** Cox proportional hazards model was used to investigate the independent risk factors for CSS.A new nomogram model was developed to predict CSS and was evaluated through internal and external *** A multivariate Cox proportional risk model was used to identify independent risk factors for ***,new CSS columns were developed based on these *** consistency index(C-index)of the histogram was 0.718(95%CI:0.712-0.725),and that of the validation cohort was 0.722(95%CI:0.711-0.732),indicating good discrimination ability and better performance than tumor-node-metastasis staging(C-index:0.712-0.732).For the training set,0.533,95%CI:0.525-0.540;for the verification set,0.524,95%CI:*** calibration map and clinical decision curve showed good agreement and good potential clinical *** risk grading system divided all patients into three groups,and the Kaplan-Meier curve showed good stratification and differentiation of CSS between different *** median CSS times in the low-risk,medium-risk,and high-risk groups were 36 months(95%CI:34.987-37.013),18 months(95%CI:17.273-18.727),and 5 months(95%CI:4.503-5.497),*** Our study developed a new nomogram model to predict CSS in patients with synchronous *** addition,the risk-grading system helps to accurately ass

关键词： Colorectal tumor Surveillance epidemiology and end results database Nomogram analysis Survival prognosis Retrospective study

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A reweighted damped singular spectrum analysis method for robust seismic noise suppression

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Petroleum Science 2024年第3期21卷 1671-1682页

作者： wei-Lin Huang Yan-Xin zhou Yang zhou wei-Jie Liu Ji-Dong Li State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China SINOPEC Petroleum Exploration and Production Research Institute Beijing102206China SINOPEC Geophysical Research Institute Nanjing211103jiangsuChina

(Multichannel)Singular spectrum analysis is considered as one of the most effective methods for seismic incoherent noise *** utilizes the low-rank feature of seismic signal and regards the noise suppression as a low-rank reconstruction ***,in some cases the seismic geophones receive some erratic disturbances and the amplitudes are dramatically larger than other *** presence of this kind of noise,called erratic noise,makes singular spectrum analysis(SSA)reconstruction unstable and has undesirable effects on the final *** robustify the low-rank reconstruction of seismic data by a reweighted damped SSA(RD-SSA)*** incorporates the damped SSA,an improved version of SSA,into a reweighted *** damping operator is used to weaken the artificial disturbance introduced by the low-rank projection of both erratic and random *** central idea of the RD-SSA method is to iteratively approximate the observed data with the quadratic norm for the first iteration and the Tukeys bisquare norm for the rest *** RD-SSA method can suppress seismic incoherent noise and keep the reconstruction process robust to the erratic *** feasibility of RD-SSA is validated via both synthetic and field data examples.

关键词： Singular spectrum analysis damping operator Seismic erratic noise Seismic signal processing Robust low-rank reconstruction

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Seasonal increase in nest defense,but not egg rejection,in a cuckoo host

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Avian Research 2024年第1期15卷 50-54页

作者： Bo zhou wei Liang Ministry of Education Key Laboratory for Ecology of Tropical Islands Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikou 571158China Institute of Biological Resources Jiangxi Academy of ScienceNanchang 330096China

The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying *** brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood *** test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic *** showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change *** results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.

关键词： Aggression Anti-parasite strategy Egg rejection Mismatch cuckoo parasitism Nest defense

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Disturbance Observer-Based Predictive Tracking Control of Uncertain HOFA Cyber-Physical Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1711-1713页

作者： da.wei Zhang Guo-Ping Liu IEEE the Center for Control Theory and Guidance Technology Harbin Institute of TechnologyHarbin 150001China the Center for Control Science and Technology Southern University of Science and TechnologyShenzhen 518055China

Dear Editor,In this letter,an output tracking control problem of uncertain cyber-physical systems(CPSs)is considered in the perspective of high-order fully actuated(HOFA)system theory,where a lumped disturbance is use... 详细信息

关键词： Observer Uncertain letter

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Shear strength degradation of gas hydrate-bearing sediment due to partial hydrate dissociation

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2749-2763页

作者： Yuan zhou Jiazuo zhou Pan Chen Changfu wei State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China China University of Geosciences Wuhan430074China

Extraction of methane hydrate from subseafloor reservoir may potentially trigger seabed slides and induce *** address the problems,it is crucial to properly characterize the phase equilibrium condition of pore hydrate and the shear strength of the *** one of the key constitutive components,the phase equilibrium condition enforces a constraint over pore gas pressure,temperature and unhydrated water *** a constraint,however,has been traditionally ignored in analyzing the mechanical behavior of hydrate-bearing *** this paper,a series of stepwise hydrate dissociation tests was performed,and the phase equilibrium condition of pore hydrate was determined,providing an effective way to evaluate the unhydrated water content during hydrate ***,a series of direct shear tests was also conducted to explore the shear strength characteristics of the *** is shown that the shear strength of the hydrate-bearing soil can be significantly influenced by pore gas pressure,unhydrated water content,hydrate saturation and several other *** particular,the measured shear strength depends upon the initial water content of the sample,pointing to a potential problem that the shear strength could be wrongly determined if not properly interpreted.A shear strength criterion,which enforces the equilibrium condition of pore hydrate,is developed for hydrate-bearing soil,establishing a link between the equilibrium condition and the shear *** proposed equation describes well the shear strength characteristics of hydrate-bearing soils,remarkably unifying the effects of pore pressure,temperature,water content and hydrate saturation.

关键词： Hydrate-bearing soil Phase equilibrium condition Shear strength Unhydrated water content Mechanical behavior

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