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Temperature prediction model in multiphase flow considering phase transition in the drilling operations

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Petroleum Science 2024年第3期21卷 1969-1979页

作者： Yang Zhang Yong-An Li xiang-Wei Kong Hao Liu Teng-fei sun College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100027China School of Petroleum Engineering Yangtze UniversityWuhan430000HubeiChina

The study considers gas compression properties,gas slippage,back pressure(BP),phase transition(PT),well depth,and differences in gas-liquid physical properties.A new temperature model for multiphase flow is proposed by considering phase transition in the drilling *** mathematical model of multiphase flow is solved using the finite difference method with annulus mesh division for grid nodes,and a module for multiphase flow calculation and analysis is *** results indicate that the temperature varies along the annulus with the variation of gas influx at the bottom of the *** the process of controlled pressure drilling,as gas slips along the annulus to the wellhead,its volume continuously expands,leading to an increase in the gas content within the annulus,and consequently,an increase in the pressure drop caused by gas *** temperature increases with the increase in BP and decreases in gas influx rate and wellbore *** gas influx,the thermal conductivity coefficient for the gas-drilling mud two phases is significantly weakened,resulting in a considerable change in temperature along the *** the context of MPD,the method of slightly changing the temperature along the annulus by controlling the back pressure is feasible.

关键词： Managed pressure drilling Phase transition Temperature Gas-drilling mud two phase

Reduction of unactivated alkyl chlorides enabled by light-induced single electron transfer

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Science China Chemistry 2024年第2期67卷 471-481页

作者： Lei Dai Zhao-fei Zhang xiang-Yu Chen School of Chemical Sciences University of the Chinese Academy of SciencesBeijing100049China Institute of Chemistry Chinese Academy of SciencesBeijing100190China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou256606China

Alkyl chlorides are abundant and easily accessible starting ***,due to the high reduction potentials associated with unactivated alkyl chlorides,achieving their single electron reduction remains a persistent *** challenge has spurred the exploration of efficient activation methods to overcome this *** recent years,photocatalysis has emerged as a mild and potent tool for the single electron reduction of unactivated alkyl chlorides,opening up new possibilities in this *** the rapid advancements in this area,a comprehensive review that provides a conceptual understanding of this emerging field,with a specific focus on reaction design and catalytic mechanisms,would be timely and highly ***,we present an overview of various synthetic techniques for photoinduced single electron reduction of unactivated alkyl ***,we also discuss the limitations of the present methods and future directions that lie ahead in this field.

关键词： photocatalysis unactivated alkyl chlorides single electron transfer radical reactions

Practical cloud storage auditing using serverless computing

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Science China(Information Sciences) 2024年第3期67卷 33-47页

作者： fei CHEN Jianquan CAI Tao xiang Xiaofeng LIAO College of Computer Science and Software Engineering Shenzhen University College of Computer Science Chongqing University

Cloud storage auditing research is dedicated to solving the data integrity problem of outsourced storage on the cloud. In recent years, researchers have proposed various cloud storage auditing schemes using different techniques. While these studies are elegant in theory, they assume an ideal cloud storage model;that is, they assume that the cloud provides the storage and compute interfaces as required by the proposed schemes. However, this does not hold for mainstream cloud storage systems because these systems only provide read and write interfaces but not the compute interface. To bridge this gap, this work proposes a serverless computing-based cloud storage auditing system for existing mainstream cloud object storage. The proposed system leverages existing cloud storage auditing schemes as a basic building block and makes two adaptations. One is that we use the read interface of cloud object storage to support block data requests in a traditional cloud storage auditing scheme. Another is that we employ the serverless computing paradigm to support block data computation as traditionally required. Leveraging the characteristics of serverless computing, the proposed system realizes economical, pay-as-you-go cloud storage auditing. The proposed system also supports mainstream cloud storage upper layer applications(e.g., file preview) by not modifying the data formats when embedding authentication tags for later auditing. We prototyped and open-sourced the proposed system to a mainstream cloud service, i.e., Tencent Cloud. Experimental results show that the proposed system is efficient and promising for practical use. For 40 GB of data, auditing takes approximately 98 s using serverless computation. The economic cost is 120.48 CNY per year, of which serverless computing only accounts for 46%. In contrast, no existing studies reported cloud storage auditing results for real-world cloud services.

关键词： cloud storage auditing serverless computing object storage usability

Meta-analysis of transarterial chemoembolization combined with cryoablation vs transarterial chemoembolization alone for≥5 cm hepatocellular carcinoma

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World Journal of Gastrointestinal Oncology 2024年第6期16卷 2793-2803页

作者： Jie-fei Cheng Qiu-Lian sun Ling Tang Xin-Jian Xu xiang-Zhong Huang Department of Radiology The Fifth People’s Hospital of TaizhouTaizhou 225300Jiangsu ProvinceChina Department of Radiology The Fifth People’s Hospital of SuzhouSuzhou 215100Jiangsu ProvinceChina Department of Radiology The Fourth People’s Hospital of TaizhouTaizhou 225300Jiangsu ProvinceChina Department of Interventional Radiology Jiangyin People HospitalJiangyin 214400Jiangsu ProvinceChina

BACKGROUND Hepatocellular carcinoma(HCC)ranks sixth globally in cancer incidence and third in mortality ***,over 70% of HCC patients forego the opportunity for curative surgery or liver transplantation due to inadequate physical examinations,poor physical condition,and limited organ availability upon *** guidelines endorse transarterial chemoembolization(TACE)as the frontline treatment for intermediate to advanced-stage ***(CRA)is an emerging local ablative therapy increasingly used in HCC *** studies suggest that combining CRA with TACE offers complementary and synergistic effects,potentially improving long-term survival ***,the superiority of combined TACE+CRA therapy over TACE alone for HCC lesions equal to or exceeding 5 cm requires further *** To compare the efficacy and safety of TACE combined with CRA vs TACE alone in the treatment of HCC with a diameter of≥5 *** PubMed,EMBASE,Cochrane Library,CNKI,Wanfang,and VIP databases were searched to retrieve all relevant studies on TACE and CRA up to July ***-analysis was performed using RevMan 5.3 *** After screening according to the inclusion and exclusion criteria,6 articles were included,including 2 randomized controlled trials and 4 nonrandomized controlled trials,with a total of 575 patients included in the *** results showed that the objective response rate[odds ratio(OR)=2.56,95%confidence interval(CI):1.66-3.96,P<0.0001],disease control rate(OR=3.03,95%CI:1.88-4.89,P<0.00001),1-year survival rate(OR=3.79,95%CI:2.50-5.76,P<0.00001),2-year survival rate(OR=2.34,95%CI:1.43-3.85,P=0.0008),and 3-year survival rate(OR=3.34,95%CI:1.61-6.94,P=0.001)were all superior to those of the control group;the postoperative decrease in alpha-fetoprotein value(OR=295.53,95%CI:250.22-340.85,P<0.0001),the postoperative increase in CD4 value(OR=10.59,95%CI:8.78-12.40,P<0.00001),and the postoperative decrease in

关键词： Hepatic cancer Cryoablation Chemoembolization Transarterial chemoembolization Meta analysis

Non-response to Implantable Cardioverter Defibrillator in a Post-Infarction Patient with Recurrent Ventricular Tachycardia After Catheter Ablation

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Chinese Medical Journal 2015年第3期128卷 415-416页

作者： xiang-fei Feng Jian sun Jun Wang Yi-Gang Li Department of Cardiology Xinhua Hospital Shanghai Jiaotong University School of Medicine Shanghai 200092 China

To the Editor： A 73-year-old man presented to Department of Cardiology at Xinhua Hospital, Shanghai Jiaotong University School of Medicine with a history of anterior wall myocardial infarction （MI） and multimorphic ventricular tachycardia （VT） in approximately September 2013. His VT burden became progressive increase despite treatment with percutaneous coronary intervention （PCI） and multiple antiarrhythmic medications such as beta blockers, amiodarone, magnesium sulfate, and so on.

关键词： Non-response Post-Infarction Patient

Biomimetic Gland Models with Engineered Stratagems

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Research 2024年第2期2023卷 583-612页

作者： xiang Lin Lingyu sun Minhui Lu Yuanjin Zhao Department of Rheumatology and Immunology Nanjng Drum Tower HospitalSchool of Biological Science and Medical EngineeringSoutheast UniversityNanjing 210096China Oujiang Laboratory(Zhejiang Lab for Regenerative Medicine Vision and Brain Health)Wenzhou InstituteUniversity of Chinese Academy of SciencesWenzhouZhejiang 325001China Southeast University Shenzhen Research Institute Shenzhen 518071China

As extensively distributed tissues throughout the human body,glands play a critical role in various physiological ***,the construction of biomimetic gland models in vitro has aroused great interest in multiple *** the biological field,the researchers focus on optimizing the cell sources and culture techniques to reconstruct the specific structures and functions of glands,such as the emergence of organoid *** the perspective of biomedical engineering,the generation of biomimetic gland models depends on the combination of engineered scaffolds and microfluidics,to mimic the in vivo environment of glandular *** engineered stratagems endowed gland models with more biomimetic features,as well as a wide range of application *** this review,we first describe the biomimetic strategies for constructing different in vitro gland models,focusing on the role of microfluidics in promoting the structure and function development of biomimetic *** summarizing several common in vitro models of endocrine and exocrine glands,the applications of gland models in disease modelling,drug screening,regenerative medicine,and personalized medicine are ***,we conclude the current challenges and our perspective of these biomimetic gland models.

关键词： endowed constructing strata

Adversarial data splitting for domain generalization

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Science China(Information Sciences) 2024年第5期67卷 28-42页

作者： xiang GU Jian sun Zongben XU School of Mathematics and Statistics Xi'an Jiaotong University

Domain generalization aims to learn a model that is generalizable to an unseen target domain,which is a fundamental and challenging task in machine learning for out-of-distribution generalization. This paper proposes a novel domain generalization approach that enforces the learned model to be able to generalize well over the train/val subset splitting of the training dataset. This idea is modeled herein as an adversarial data splitting framework, formulated as a min-max optimization problem inspired by the metalearning approach. The min-max optimization problem is solved by iteratively splitting the training dataset into the training and val subsets to maximize the domain shift measured by the objective function and updating the model parameters to enable the model to generalize well from the training subset to the val subset by minimizing the objective function. This adversarial training approach does not assume the known domain labels of the training data; instead, it automatically investigates the “hard” splitting of the train/val subsets to learn the generalizable model. Extensive experimental results using three benchmark datasets demonstrate the superiority of this approach. In addition, we derive a generalization error bound for the theoretical understanding of our proposed approach.

关键词： domain generalization adversarial learning data splitting meta-learning out of distribution

makeTwin:A reference architecture for digital twin software platform

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Chinese Journal of Aeronautics 2024年第1期37卷 1-18页

作者： fei TAO Xuemin sun Jiangfeng CHENG Yonghuai ZHU Weiran LIU Yong WANG Hui XU Tianliang HU Xiaojun LIU Tingyu LIU Zheng sun Jun XU Jinsong BAO Feng xiang Xiaohui JIN Digital Twin International Research Center International Research Institute for Multidisciplinary ScienceBeihang UniversityBeijing 100191China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Institute of Advanced Manufacturing and Intelligent Technology Beijing University of TechnologyBeijing 100124China RIAMB(Beijing)Technology Development Co Ltd(R.T.D.)Beijing 100120China School of Mechanical Engineering Shandong UniversityJinan 250061China School of Mechanical Engineering Southeast UniversityNanjing 211189China School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China College of Mechanical Engineering Donghua UniversityShanghai 201620China School of Machinery and Automation Wuhan University of Science and TechnologyWuhan 430081China Beijing Aero-top Hi-tech Co LtdBeijing 100176China

Digital twin is currently undergoing a significant transformation from the conceptual and theoretical research phase to the implementation and application ***,a universally adaptable research and development platform for digital twin is critically needed to meet the development ***,a publicly accessible simulation,testing,and validation platform which can support digital twin model building,data processing,algorithm design,configuration,etc.,is urgently required for ***,for developers from the industry,a lowcode development platform that can offer a customizable suite of functions such as model creation,data management,protocol configuration,and visualization is urgently ***,for enterprise users,there is a lack of an application management platform that can be configured and migrated for various application scenarios,functions,and ***,based on the system research of digital twin theories and key technologies by the authors(such as the five-dimension digital twin model,digital twin modeling and digital twin data theory,digital twin standards,and so on),a digital twin software platform reference architecture,namely make Twin,is proposed and designed,as well as its ten core *** workflow of the make Twin and the interaction mechanisms among its core functions are ***,a digital twin application system for a chemical fiber textile shop floor(CFTS)which was developed according to make Twin,is introduced,which validates the proposed reference architecture.

关键词： Digital twin Digital twin software platform Industrial software makeTwin Reference architecture

A DFT study on Pt single atom loaded COF for efficient photocatalytic CO_(2)reduction

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Journal of Materials Science & Technology 2024年第3期170卷 87-94页

作者： fei Xie Chuanbiao Bie Jian sun Zhenyi Zhang Bicheng Zhu Laboratory of Solar Fuel Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan430078China Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission Key Laboratory of Photosensitive Materials and Devices of Liaoning ProvinceSchool of Physics and Materials EngineeringDalian Minzu UniversityDalian116600China

Photocatalytic CO_(2)reduction provides a promising strategy for the alleviation of greenhouse effect and energy shortage *** single atom modification is an effective method to improve the CO_(2)reduction performance of covalent organic framework(COF)photocatalysts,while the intrinsic mechanism is not revealed in ***,a Pt-COF photocatalytic system was constructed by embedding Pt single atom in TFPT-TMT-COF(TFPT:1,3,5-tris(4-formylphenyl)-triazine,TMT:2,4,6-trimethyl-1,3,5-triazine).Based on density functional theory(DFT)calculation,the geometric structure and electronic property of Pt-COF were investigated,and the CO_(2)adsorption and reduction reaction process on Pt-COF were *** results show that the Pt atom can be steadily anchored in COF via the formation of Pt-N and Pt-C ***,there is strong electronic interaction between Pt and *** incorporation of Pt atom benefits the CO_(2)reduction activity of COF from multiple aspects:(ⅰ)reducing the band gap and improving light absorption;(ⅱ)enhancing CO_(2)adsorption and activating the CO_(2)molecule;(ⅲ)decreasing the energy barrier in the hydrogenation step of CO_(2)→COOH,thus facilitating CO_(2)conversion to CO;(ⅳ)inhibiting the hydrogenation of CO,thereby increasing the selectivity of *** work brings a novel insight into the excellent CO_(2)reduction performance of Pt modified COF,and provides useful references for the design of single atom photocatalysts.

关键词： Photocatalysis Carbon dioxide reduction Covalent organic framework Pt single atom Theoretical calculation