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Study on the clogging mechanism of punching screen in sand control by the punching structure parameters

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Petroleum Science 2024年第1期21卷 609-620页

作者： Fu-cheng Deng Fu-Lin Gui Bai-Tao Fan Lei Wen Sheng-Hong chen Ning Gong Yun-chen xiao Zhi-hui Xu Yangtze University Jingzhou434023HubeiChina CNOOC Research Institute Ltd. Beijing100028China CNOOC Ener Tech-Drilling&Production Co. Tianjin300457China Tianjin Branch of CNOOC Ltd. Tianjin300459China

As an independent sand control unit or a common protective shell of a high-quality screen,the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and gas ***,most screens only consider the influence of the internal sand retaining medium parameters in the sand control performance design while ignoring the influence of the plugging of the punching screen on the overall sand retaining performance of the *** explore the clogging mechanism of the punching screen,this paper established the clogging mechanism calculation model of a single punching screen sand control unit by using the computational fluid mechanics-discrete element method(CFD-DEM)combined *** to the combined motion of particles and fluids,the influence of the internal flow state on particle motion and accumulation was *** results showed that(1)the clogging process of the punching sand control unit is divided into three stages:initial clogging,aggravation of clogging and stability of *** the initial stage of blockage,coarse particles form a loose bridge structure,and blockage often occurs preferentially at the streamline gathering place below chamfering inside the sand control *** the stage of blockage intensification,the particle mass develops into a relatively complete sand bridge,which develops from both ends of the opening to the center of the *** the stable plugging stage,the sand deposits show a“fan shape”and form a“V-shaped”gully inside the punching slot element.(2)Under a certain reservoir particle-size distribution,The slit length and opening height have a large influence on the permeability and blockage rate,while the slit width size has little influence on the permeability and blockage *** microscopic clogging mechanism and its law of the punching screen prevention unit are proposed in this study,which has some field guidance significance for the design of punching screen

关键词： Punching screen Plugging CFD-DEM Size parameter Sand control

Data-Driven Design for Targeted Regulation of Heat Transfer in Carbon/Carbon Composite Structure

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Journal of Thermal Science 2024年第2期33卷 648-657页

作者： xiao Heye WANG Zelin WANG hui JI Ritian Unmanned System Research Institute Northwestern Polytechnical UniversityXi’an710072China School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China MOE Key Laboratory of Thermo-Fluid Science and Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China

Targeted regulation of heat transfer in carbon/carbon composite structure is built for cooling electronic device.A three-dimensional data-driven design model coupling genetic algorithm(GA) with self-adaption deep learning for targeted regulation of heat transfer in built structure is *** self-adaption deep learning model predicts the temperature of built structure closer to optimal value in GA *** distributions of pore and carbon fiber bundles in built structure are optimized by the proposed *** surface temperature of electronic device in the optimized structures is 19.1%-27.5% lower than that in the initial configurations when the porosity of built structure varies from 3% to 11%.The surface temperature of electronic device increases with an increase in *** built structure with carbon fiber bundles near the surface of electronic device and pore distribution in the middle of structure has a higher heat dissipation capacity compared with that in the initial ***,the computation time of the proposed model is less than one tenth compared with that of the traditional genetic algorithm.

关键词： targeted regulation of heat transfer self-adaption deep learning genetic algorithm carbon/carbon composite structure

Distributed Source-Load-Storage Cooperative Low-Carbon Scheduling Strategy Considering Vehicle-to-Grid Aggregators

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 440-453页

作者： xiao Xu Ziwen Qiu Teng Zhang hui Gao School of Automation Nanjing University of Posts and TelecommunicationsNanjing210023China

The vehicle-to-grid(V2G)technology enables the bidirectional power flow between electric vehicle(EV)batteries and the power grid,making EV-based mobile energy storage an appealing supplement to stationary energy storage ***,the stochastic and volatile charging behaviors pose a challenge for EV fleets to engage directly in multi-agent *** unlock the scheduling potential of EVs,this paper proposes a source-load-storage cooperative low-carbon scheduling strategy considering V2G *** uncertainty of EV charging patterns is managed through a rolling-horizon control framework,where the scheduling and control horizons are adaptively adjusted according to the availability periods of ***,a Minkowski-sum based aggregation method is employed to evaluate the scheduling potential of aggregated EV fleets within a given scheduling *** method effectively reduces the variable dimension while preserving the charging and discharging constraints of individual ***,a Nash bargaining based cooperative scheduling model involving a distribution system operator(DSO),an EV aggregator(EVA),and a load aggregator(LA)is established to maximize the social welfare and improve the low-carbon performance of the *** model is solved by the alternating direction method of multipliers(ADMM)algorithm in a distributed manner,with privacy of participants fully *** proposed strategy is proven to achieve the objective of low-carbon economic operation.

关键词： Electric vehicle(EV) low-carbon scheduling mobile storage system Nash bargaining power flexibility alternating direction method of multipliers(ADMM).

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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Bioinspired nanomaterials for wearable sensing and human–machine interfacing

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Nano Research 2024年第2期17卷 445-461页

作者： Vishesh Kashyap Junyi Yin xiao xiao Jun chen Department of Bioengineering University of CaliforniaLos AngelesLos AngelesCA 90095USA Department of Mechanical and Aerospace Engineering University of CaliforniaLos AngelesLos AngelesCA 90095USA

The inculcation of bioinspiration in sensing and human–machine interface(HMI)technologies can lead to distinctive characteristics such as conformability,low power consumption,high sensitivity,and unique properties like self-healing,self-cleaning,and *** sensing and HMI are fields rife with opportunities for the application of bioinspired nanomaterials,particularly when it comes to wearable sensory systems where biocompatibility is an additional *** review discusses recent development in bioinspired nanomaterials for wearable sensing and HMIs,with a specific focus on state-of-the-art bioinspired capacitive sensors,piezoresistive sensors,piezoelectric sensors,triboelectric sensors,magnetoelastic sensors,and electrochemical *** also present a comprehensive overview of the challenges that have hindered the scientific advancement in academia and commercialization in the industry.

关键词： bioinspired nanomaterials human–machine interface wearable sensors wearable bioelectronics

Berry-Esseen bounds and moderate deviations for the norm, entries and spectral radius of products of positive random matrices

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Science China Mathematics 2024年第3期67卷 627-646页

作者： hui xiao Ion Grama Quansheng Liu Institut fur Mathematik und Angewandte Informatik Universitat HildesheimHildesheim 31141Germany Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China LMBA Universite Bretagne SudCNRS UMR 6205Vannes F-56000France

Let(g_(n))_(n≥1) be a sequence of independent and identically distributed positive random d×d matrices and consider the matrix product G_(n)=g_(n)…g_*** suitable conditions,we establish the Berry-Esseen bounds on the rate of convergence in the central limit theorem and Cramer-type moderate deviation expansions,for any matrix norm ‖G_(n)‖ of G_(n),its entries G_(n)^(i,j) and its spectral radius ρ(G_(n)).Extended versions of their joint law with the direction of the random walk G_(n)x are also established,where x is a starting point in the unit sphere of R~d.

关键词： Berry-Esseen bound Cramér-type moderate deviation product of random matrices operator norm entry spectral radius

Matrix metalloproteinase 2 degrades collagen I to regulate ovarian development by association with an insulin-like peptide

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Insect Science 2024年第4期31卷 1090-1106页

作者： Yi Wei xiao-Lin Zhou Peng chen Tai-Hang Liu cheng Lu Min-hui Pan State Key Laboratory of Silkworm Genome Biology Southwest UniversityChongqingChina Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry Southwest UniversityChongqingChina Wenzhou Institute University of Chinese Academy of SciencesWenzhouZhejiang ProvinceChina

The ovary generally undergoes tissue remodeling during larval to pupal transition,which includes membrane degeneration and ovariole *** the same time,the hormones produced by insects significantly change during ***,the regulatory mechanism for ovarian development and hormones is not fully understood in ***,we found that matrix metalloproteinase 2(MMP2)was highly expressed in the ovarian capsules and ovarioles,and the development was abnormal after knocking out MMP2 in Bombyx *** process of abnormal degradation of collagen I due to MMP2 deletion,which resulted in abnormal development of ovarioles and eggs,was analyzed in *** proteomics of ovaries in the MMP2-knock out and wild type strains showed a critically significant difference in the expression of a protein,insulin-like peptide(ILP).Additional analysis revealed significant alteration of ILP during ovarian development,and abnormal expression of ILP significantly affected ovarian development in vivo and MMP2 expression in vitro and in *** results showed that MMP2 regulation of ovarian tissue remodeling is closely related to ILP *** study provides new insights into the regulatory mechanism of MMP2 and ovarian development in ***.

关键词： Bombyx mori collagen I insulin-like peptide matrix metalloproteinase ovarian development

急性上消化道出血患者预后预测模型的构建与验证

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岭南急诊医学杂志 2024年第2期29卷 86-91页

作者：韩家豪林树豪林珮仪莫均荣江慧琳陈晓辉朱永城刘健峰广州医科大学附属第二医院急诊科 510260

目的:分析急性上消化道出血(Acute Upper Gastrointestinal Bleeding,AUGIB)住院患者不良预后风险因素,构建AUGIB患者短期不良预后风险预测模型,为AUGIB管理及风险分层提供参考。方法:回顾性分析由2016年9月至2022年6月来自广州医科大... 详细信息

目的:分析急性上消化道出血(Acute Upper Gastrointestinal Bleeding,AUGIB)住院患者不良预后风险因素,构建AUGIB患者短期不良预后风险预测模型,为AUGIB管理及风险分层提供参考。方法:回顾性分析由2016年9月至2022年6月来自广州医科大学附属第二医院由急诊入院的AUGIB患者,按7∶3分为训练集及验证集。通过Lasso回归、多因素Logistic回归构建预测模型并进行预测能效评估。结果:消化系统恶性肿瘤、休克指数>1、GCS评分103μmol/L与AUGIB患者预后不良相关。使用上述变量组成的评分量表,与GBS评分在预测不良预后上有统计学差异(0.826 vs 0.700,P=0.002),与AIMS 65评分无统计学差异(0.826 vs 0.768,P=0.260)。结论:由消化系统恶性肿瘤、休克指数>1、GCS评分103μmol/L五个变量构建的预测模型对于AUGIB患者不良预后具有良好的预测能效,其预测价值与AIMS 65评分相当,可能优于GBS评分。

关键词：急性上消化道出血预后危险因素预测模型

Uniqueness on Difference Operators of Meromorphic Functions of Infinite Order

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Acta Mathematica Sinica,English Series 2024年第2期40卷 511-527页

作者： hui LI Ming Liang FANG xiao YAO School of Science China University of Mining and TechnologyBeijing 100083P.R.China Institute of Mathematics Academy of Mathematics and System SciencesChinese Academy of SciencesBeijing 100190P.R.China School of Sciences Hangzhou Dianzi UniversityHangzhou 310012P.R.China School of Mathematical sciences and LPMC Nankai UniversityTianjin 300071P.R.China

We investigate the uniqueness problems of meromorphic functions and their difference operators by using a new *** is proved that if a non-constant meromorphic function f shares a non-zero constant and ∞ counting multiplicities with its difference operators Δcf(z) and Δ_(c)^(2)f(z), thenΔcf(z)≡Δ_(c)^(2)f(z).In particular,we give a difference analogue of a result of *** method has two distinct features:(ⅰ) It converts the relations between functions into the corresponding *** makes it possible to deal with the uniqueness problem by linear algebra and combinatorics.(ⅱ) It circumvents the obstacle of the difference logarithmic derivative lemma for meromorphic functions of infinite order,since this method does not depend on the growth of the ***,the idea in this paper can also be applied to the case for several variables.

关键词： Uniqueness meromorphic functions difference operators infinite order