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An unequal fracturing stage spacing optimization model for hydraulic fracturing that considers cementing interface integrity

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Petroleum Science 2023年第4期20卷 2165-2186页

作者： xu Han Fu-Ping Feng xiao-chuan Zhang Jing Cao Jun Zhang Yu Suo Yan Yan Mao-Sen Yan Department of Petroleum Engineering Northeast Petroleum UniversityDaqing163318HeilongjiangChina Daqing Oil Field Limited-Liability Company Daqing163453HeilongjiangChina Tubular Goods Research Institute of CNPC Xi’an710000ShaanxiChina

Determining reasonable fracturing stage spacing is the key to horizontal well *** from traditional stage spacing optimization methods based on the principle of maximum stimulated reservoir volume,in this paper,by considering the integrity of the wellbore interface,a fracture propagation model was established based on displacement discontinuity method and the competition mechanism of multifracture joint expansion,leading to the proposal of an unequal stage spacing optimization *** results show that in the first stage,the interfacial fractures spread symmetrically along the axis of the central point during that stage,while in the second and subsequent stages,the interfacial fractures of each cluster extend asymmetrically along the left and right *** are two kinds of interface connectivity behaviour:in one,the existing fractures first extend and connect within the stage,and in the other,the fractures first extend in the direction close to the previous stage,with the specific behaviour depending on the combined effect of stress shadow and flow competition during hydraulic fracture *** stage spacing is positively correlated with the number of fractures and Young’s modulus of the cement and formation and is negatively correlated with the cluster spacing and horizontal principal stress *** sensitivity is the strongest when the Young’s modulus of the cement sheath is 10-20 GPa,and the sensitivity of the horizontal principal stress difference is the weakest.

关键词： Hydraulic fracturing Cementing interface Fracture propagation Fracturing stage spacing Wellbore integrity

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Development of calcium coke for CaC2 production using calcium carbide slag and coking coal

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International Journal of Minerals,Metallurgy and Materials 2021年第1期28卷 76-87页

作者： xu-zhong Gong Jun-qiang Zhang Zhi Wang Dong Wang Jun-hao Liu xiao-dong Jing Guo-yu Qian chuan Wang Key Laboratory of Green Process and Engineering National Engineering Laboratory for Hydrometallurgical Cleaner Production TechnologyInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Chemical Engineering School University of Chinese Academy of SciencesBeijing 100049China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing 100190China Department of Process Metallurgy Swerim ABLulea 97125Sweden

A type of calcium coke was developed for use in the oxy-thermal process of calcium carbide *** calcium coke was prepared by the co-pyrolysis of coking coal and calcium carbide slag, which is a solid waste generated from the chlor-alkali *** characteristics of the calcium cokes under different conditions were analyzed experimentally and *** results show that the thermal strength of calcium coke increased with the increase in the coking coal proportion, and the waterproof property of calcium coke also increased with increased carbonation *** calcium coke can increase the contact area of calcium and carbon in the calcium carbide production ***, the pore structure of the calcium coke can enhance the diffusion of gas inside the furnace, thus improving the efficiency of the oxy-thermal technology.

关键词： calcium carbide slag calcium carbide production calcium coke thermal strength waterproof property

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Prediction Model of Kinetic Energy Conversion of Tandem Dual-Oscillator Based on Flow-Induced Vibration Experiment

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China Ocean Engineering 2022年第5期36卷 707-719页

作者： BAI xu SUN Meng HAN chuan-yu SUN Hai School of Naval Architecture&Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Marine Renewable Energy Laboratory Department of Naval Architecture&Marine EngineeringUniversity of MichiganAnn Arbor MI 48109-2145USA College of Aerospace and Civil Engineering Harbin Engineering UniversityHarbin 150001China

Flow-induced vibration energy harvesting devices typically use an elastically supported body immersed in an oncoming flow to convert the sea and river current's hydrokinetic energy into electrical *** proportion of energy the device collects is greatly influenced by parameters such as the water flow velocity,spacing between device components,structure size,and damping *** parameter optimization and performance predictions of flow-induced vibration energy harvesting devices,we train a model of the power harvesting efficiency under different damping ratios,stiffnesses,spacing ratios,and reduced velocities based on experimental *** improve the prediction accuracy,a feedforward network structure is optimized by using the topological evolutionary algorithm and a radial basis function *** analysis reveals that the radial basis function network model provides the best agreement with the experimental results and realizes accurate predictions of the power harvested by a dual-oscillator system in the vortex-induced vibration,transition region,and *** prediction results show that the model's maximum power harvesting efficiency occurs in the vortex-induced *** efficiency increases and then decreases with increasing stiffness and reduced velocity in this phase;an increase in the spacing ratio causes the effi-ciency to decrease and then increase;finally,increasing the damping ratio enhances the *** device achieves maximum power harvesting efficiency at a reduced velocity of U_(r)=*** proposed model effectively predicts the maximum efficiency and the corresponding damping ratio and stiffness of the vortex-induced vibration and galloping,providing a new method for predicting tandem dual-oscillator hydrodynamic power conversion in flow-induced vibration.

关键词： flow-induced vibration tandem double-oscillator radial basis function prediction

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A survey on de novo assembly methods for single-molecular sequencing

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Quantitative Biology 2020年第3期8卷 203-215页

作者： Ying Chen chuan-Le xiao State Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterSun Yat-Sen UniversityGuangzhou 510275China

Background:The single-molecular sequencing(SMS)is under rapid development and generating increasingly long and accurate *** novo assembly of genomes from SMS sequences is a critical step for many genomic *** scale well with the developing trends of SMS,many de novo assemblers for SMS have been *** assembly workflows can be categorized into two different kinds:the correction-and-assembly strategy and the assembly-and-correction strategy,both of which are gaining more and more ***:In this article we make a discussion on the characteristics of errors in SMS sequences・We then review the currently widely applied de novo assemblers for SMS *** also describe computational methods relevant to de novo assembly,including the alignment methods and the error correction *** are provided to analyze their performance on different datasets and to provide use guides on applying the computation ***:We make a detailed review on the latest development of de novo assembly and some relevant algorithms for SMS,including their rationales,solutions and ***,we provide use guides on the algorithms based on their benchmark *** we conclude the review by giving some developing trends of third generation sequencing(TGS).

关键词： third generation sequencing single-molecular real-time sequencing sequence alignment sequence error correction de novo assembly

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Numerical study on transom stern ventilation and resistance of high-speed ship in calm water

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Journal of Hydrodynamics 2022年第5期34卷 864-875页

作者： Hui Wang Ren-chuan Zhu Meng-xiao Gu Le Zha State Key Laboratory of Ocean Engineering School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Marine Design and Research Institute of China Shanghai200011China

A transom stern is a common design feature for a high-speed *** the present study,the transom stern ventilation of NPL 3b,5b hull is investigated by three methods:H−H formula,Doctors’formula,and computational fluid dynamics(CFD)method at *** the CFD method,the ratios of the wave elevation and wetted area are used to determine the transom *** of results show that Doctors’formula is more accurate to calculate the critical transom draft Froude *** then a Rankine panel method(RPM)based on the high-order boundary element method incorporated the modified transom stern condition is implemented to evaluate the steady wave problem of a high-speed fishery patrol ship in calm ***,free-surface(FS)and double body(DB)simulations based on Star-CCM+are carried out to obtain the wave-making resistance and total *** results of the resistance and wave pattern around the fishery patrol ship computed by RPM show generally good agreement with experimental measurement and CFD *** results indicate that the developed Rankine panel method with transom condition could predict the resistance of high-speed displacement ships with good accuracy.

关键词： Transom ventilation computational fluid dynamics(CFD)method Rankine panel method(RPM) high-speed ship double body simulation resistance

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Stretchable fiber strain sensors for wearable biomonitoring

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National Science Review 2024年第7期11卷 70-71页

作者： Shumao xu xiao xiao Jun Chen Department of Bioengineering University of California

Wearable bioelectronics have gained significant attention since they may play a role in transforming current healthcare from a reactive and disease-centric model to a personalized one with a focus on disease preventio...

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New Algebraic Approaches to Classical Boundary Layer Problems

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Acta Mathematica Sinica,English Series 2011年第6期27卷 1023-1070页

作者： xiao Ping xu Hua Loo-Keng Mathematical Laboratory Institute of MathematicsAcademy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 P. R. China

Classical non-steady boundary layer equations are fundamental nonlinear partial differential equations in the boundary layer theory of fluid dynamics. In this paper, we introduce various schemes with multiple parameter functions to solve these equations and obtain many families of new explicit exact solutions with multiple parameter functions. Moreover, symmetry transformations are used to simplify our arguments. The technique of moving frame is applied in the three-dimensional case in order to capture the rotational properties of the fluid. In particular, we obtain a family of solutions singular on any moving surface, which may be used to study turbulence. Many other solutions are analytic related to trigonometric and hyperbolic functions, which reflect various wave characteristics of the fluid. Our solutions may also help engineers to develop more effective algorithms to find physical numeric solutions to practical models.

关键词： Boundary layer equation symmetry transformation moving frame exponential approach,trigonometric approach hyperbolic approach rational approach

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A General Comparison Theorem for 1-dimensional Anticipated BSDEs

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Acta Mathematicae Applicatae Sinica 2016年第2期32卷 343-348页

作者： xiao-ming xu Institute of Finance and Statistics School of Mathematical Sciences Nanjing Normal University

Anticipated backward stochastic differential equation （ABSDE） studied the first time in 2007 is a new type of stochastic differential equations. In this paper, we establish a general comparison theorem for ABSDEs.

关键词： anticipated backward stochastic differential equation backward stochastic differential equation comparison theorem

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A New Functor from D_5-Mod to E_6-Mod

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Acta Mathematica Sinica,English Series 2016年第8期32卷 867-892页

作者： xiao Ping xu Hua Loo-Keng Key Mathematical Laboratory Institute of MathematicsAcademy of Mathematics & System SciencesChinese Academy of Sciences

We find a new representation of the simple Lie algebra of type E6 on the polynomial algebra in 16 variables, which gives a fractional representation of the corresponding Lie group on 16-dimensional space. Using this representation and Shen＇s idea of mixed product, we construct a new functor from Ds-Mod to E6-Mod. A condition for the functor to map a finite-dimensional irreducible Ds-module to an infinite-dimensional irreducible E6-module is obtained. Our results yield explicit constructions of certain infinite-dimensional irreducible weight E6-modules with finite-dimensional weight subspaces. In our approach, the idea of Kostant＇s characteristic identities plays a key role.

关键词： Simple Lie algebra of type E6 simple Lie algebra of type Ds module category functor,irreducibility

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Indirect comparison between abiraterone acetate and enzalutamide for the treatment of metastatic castration-resistant prostate cancer： a systematic review

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Asian Journal of Andrology 2017年第2期19卷 196-202页

作者： Wei Zhang Teng-Yun Wu Qi Chen xiao-Lei Shi Guang-An xiao Lin Zhao chuan-Liang xu Tie Zhou Ying-Hao Sun Department of Urology Changhai Hospital Second Military Medical University Shanghai China Air Force General Hospital of Chinese People's Liberation Army Beijing China Department of Health Statistics Faculty of Health Service Second Military Medical University Shanghai China

This study was designed to evaluate the efficacy, tolerability, and sequential administration of abiraterone acetate （AA） and enzalutamide （Enz） for metastatic castration-resistant prostate cancer （mCRPC）. A literature search was performed with PubMed, Embase, and Web of Science databases to identify relevant studies. Reviewed literature included published phase III trials of AA or Enz in mCRPC and studies regarding their sequential administration. Given the difference in control arms in AA （active comparator） and Enz （true placebo） randomized phase III studies, indirect comparisons between AA and Enz in mCRPC showed no statistically significant difference in overall survival in prechemotherapy and postchemotherapy settings （HR. 0.90, 95% CI, 0.73-1.11; HR： 0.85, 95% CI, 0.68-1.07）. Compared with AA, Enz may better outperform control arms in treating mCRPC both before and after chemotherapy regarding secondary endpoints based on indirect comparisons： time to prostate-specific antigen （PSA） progression （HR. 0.34, 95% CI, 0.28-0.42; HR： 0.40, 95% CI, 0.30-0.53）, radiographic progression-free survival （HR： 0.37, 95% CI, 0.28-0.48; HR： 0.61, 95% CI, 0.50-0.74）, and PSA response rate （OR： 18.29, 95% CI, 11.20-29.88; OR： 10.69, 95% CI, 3.92-29.20）. With regard to the effectiveness of Enz following AA or AA following Enz, recent retrospective case series reported overall survival and secondary endpoints for patients with mCRPC progression after chemotherapy. However, confirmatory head-to-head trials are necessary to determine the optimal sequencing of these agents.

关键词： abiraterone acetate enzalutamide indirect comparison metastatic castration-resistant prostate cancer sequential therapy

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