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A real-time intelligent lithology identification method based on a dynamic felling strategy weighted random forest algorithm

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Petroleum Science 2024年第2期21卷 1135-1148页

作者： tie Yan Rui Xu Shi-Hui Sun Zhao-kai Hou Jin-Yu Feng School of Petroleum Engineering Northeast Petroleum UniversityDaqing163318HeilongjiangChina Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya572025HainanChina

Real-time intelligent lithology identification while drilling is vital to realizing downhole closed-loop drilling. The complex and changeable geological environment in the drilling makes lithology identification face many challenges. This paper studies the problems of difficult feature information extraction,low precision of thin-layer identification and limited applicability of the model in intelligent lithologic identification. The author tries to improve the comprehensive performance of the lithology identification model from three aspects: data feature extraction, class balance, and model design. A new real-time intelligent lithology identification model of dynamic felling strategy weighted random forest algorithm(DFW-RF) is proposed. According to the feature selection results, gamma ray and 2 MHz phase resistivity are the logging while drilling(LWD) parameters that significantly influence lithology identification. The comprehensive performance of the DFW-RF lithology identification model has been verified in the application of 3 wells in different areas. By comparing the prediction results of five typical lithology identification algorithms, the DFW-RF model has a higher lithology identification accuracy rate and F1 score. This model improves the identification accuracy of thin-layer lithology and is effective and feasible in different geological environments. The DFW-RF model plays a truly efficient role in the realtime intelligent identification of lithologic information in closed-loop drilling and has greater applicability, which is worthy of being widely used in logging interpretation.

关键词： Intelligent drilling Closed-loop drilling Lithology identification Random forest algorithm Feature extraction

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Portal vein embolization combined with ex vivo liver resection and autotransplantation: A novel treatment strategy for end-stage and metastatic hepatic alveolar echinococcosis

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Hepatobiliary & Pancreatic Diseases International 2024年第2期23卷 210-216页

作者： Qiang Guo Mao-Lin Wang kai Zhong Jia-Long Li tie-Min Jiang Hao Wen Tuerganaili Aji Ying-Mei Shao Department of Hepatobiliary and Echinococcosis Surgery Digestive and Vascular Surgery CenterFirst Affiliated Hospital of Xinjiang Medical UniversityUrumqi 830054China Clinical Medical Research Center of Echinococcosis and Hepatobiliary Disease of Xinjiang Uygur Autonomous Region Urumqi 830054China State Key Laboratory of Pathogenesis Prevention and Treatment of High Incidence Diseases in Central AsiaXinjiang Medical UniversityUrumqi 830054China

Alveolar echinococcosis(AE)is a lethal parasitic disease caused by Echinococcus multilocularis larvae,and more than 90%of pri-mary AE lesions occur in the liver.Most of the affected individ-uals remain asymptomatic and the disease is often diagnosed at an advanced stage.The infection may spread to organs adjacent to the liver or distant locations,eventually causing end-stage multi-ple organ AE.Brain metastasis of AE is the most fatal with an inci-dence rate of 0.2%[1].

关键词： organs echinococcosis metastasis

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Mesenchymal stem cell-derived exosomes as a new drug carrier for the treatment of spinal cord injury:A review

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Chinese Journal of Traumatology 2024年第3期27卷 134-146页

作者： Lin-Fei Cheng Chao-Qun You Cheng Peng Jjia-ji Ren kai Guo tie-Long Liu Medical Collge.Anhui University of Science and Technology Huainan232000Anhui provinceChina Department of Orthopaedic Oncology Changzheng HospitalNavy Medical UniversityShanghai200003China Department of Orthopaedics The Central Hospital of Shanghai Putuo DistrictShanghai200333China

Spinal cord injury(SCI)is a devastating traumatic disease seriously impairing the quality of life in patients.Expectations to allow the hopeless central nervous system to repair itself after injury are unfeasible.Developing new approaches to regenerate the central nervous system is still the priority.Exosomes derived from mesenchymal stem cells(MSC-Exo)have been proven to robustly quench the inflammatory response or oxidative stress and curb neuronal apoptosis and autophagy following SCI,which are the key processes to rescue damaged spinal cord neurons and restore their functions.Nonetheless,MSC-Exo in SCI received scant attention.In this review,we reviewed our previous work and other studies to summarize the roles of MSC-Exo in SCI and its underlying mechanisms.Furthermore,we also focus on the application of exosomes as drug carrier in SCI.In particular,it combs the advantages of exosomes as a drug carrier for SCI,imaging advantages,drug types,loading methods,etc.,which provides the latest progress for exosomes in the treatment of SCI,especially drug carrier.

关键词： Spinal cord injury Mesenchymal stem cell Exosomes Mechanism Drug carrier

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Hydrogen and nitrogen absorption properties of Ce-added Zr_(2)(Fe_(1-x)Ni_(x)) alloys

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Journal of Rare Earths 2024年第6期42卷 1136-1141,I0005页

作者： kai Yin Xiaopeng Liu State Key Laboratory of Advanced Materials for Smart Sensing GRINM Group Co.Ltd.Beijing10088China GRIMAT Engineering Institute Co. Ltd.Beijing101407China General Research Institute of Nonferrous Metals Beijing100088China

To improve the nitriding resistance of Zr_(2)Fe alloy,the Ce-added Zr_(2)(Fe_(1-x)Ni_(x))(x=0,0.15,0.3,0.5)alloys were prepared by magnetic levitation melting method.The effects of Ni substitution for Fe on the phase structure,hydrogen and nitrogen absorption properties of the alloys were investigated by X-ray diffraction,scanning electron microscopy and p-c isotherm measurements.The experimental results show that Ni substitution can effectively inhibit the formation of both α-Zr and ZrFe_(2) phases and promote the formation of C16 structure Zr_(2)(Fe,Ni)phase,causing Ni-substituted alloys to exhibit low nitrogen absorption rate and capacity.At 623 K under 0.5 MPa nitrogen pressure,the nitrogen absorption capacity of Ce-added Zr_(2)(Fe_(0.5)Ni_(0.5))alloy reaches to 0.8 mL/g,much lower than that of Zr_(2)Fe alloy(1.5 mL/g).Ni substitution decreases the crystal cell volume of the C_(16)Zr_(2)(Fe,Ni)phase,resulting in an increase in the hydrogen absorption equilibrium pressure.At 623 K under 0.05 MPa hydrogen pressure,the hydrogen absorption capacity decreases from 1.46 wt%of Zr_(2)Fe alloy to 1.41 wt%of Ce-added Zr_(2)(Fe_(0.5)Ni_(0.5))alloy.

关键词： Zr_(2)Fe alloy Ce Pressure-composition isotherm Hydrogen absorption Nitrogen absorption Rare earths

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Adaptive state-constrained/model-free iterative sliding mode control for aerial robot trajectory tracking

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 603-618页

作者： Chen AN Jiaxi ZHOU kai WANG College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong KongChina

This paper develops a novel hierarchical control strategy for improving the trajectory tracking capability of aerial robots under parameter uncertainties.The hierarchical control strategy is composed of an adaptive sliding mode controller and a model-free iterative sliding mode controller(MFISMC).A position controller is designed based on adaptive sliding mode control(SMC)to safely drive the aerial robot and ensure fast state convergence under external disturbances.Additionally,the MFISMC acts as an attitude controller to estimate the unmodeled dynamics without detailed knowledge of aerial robots.Then,the adaption laws are derived with the Lyapunov theory to guarantee the asymptotic tracking of the system state.Finally,to demonstrate the performance and robustness of the proposed control strategy,numerical simulations are carried out,which are also compared with other conventional strategies,such as proportional-integralderivative(PID),backstepping(BS),and SMC.The simulation results indicate that the proposed hierarchical control strategy can fulfill zero steady-state error and achieve faster convergence compared with conventional strategies.

关键词： aerial robot hierarchical control strategy model-free iterative sliding mode controller(MFISMC) trajectory tracking reinforcement learning

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Sequential Propagation of Chaos for Mean-Field BSDE Systems

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 11-40页

作者： Xiaochen LI kai DU Shanghai Center for Mathematical Sciences Fudan UniversityShanghai 200433China. Shanghai Artificial Intelligence Laboratory 701 Yunjin RoadShanghai 200433China

A new class of backward particle systems with sequential interaction is proposed to approximate the mean-field backward stochastic differential equations.It is proven that the weighted empirical measure of this particle system converges to the law of the McKean-Vlasov system as the number of particles grows.Based on the Wasserstein met-ric,quantitative propagation of chaos results are obtained for both linear and quadratic growth conditions.Finally,numerical experiments are conducted to validate our theoretical results.

关键词： Backward propagation of chaos Particle system Sequential interaction McKean-Vlasov BSDE Convergence rate

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Adaptive learning-based optimal tracking control system design and analysis of a disturbed nonlinear hypersonic vehicle model

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Science China Technological Sciences 2024年第6期67卷 1893-1906页

作者： AN kai WANG ZhenGuo HUANG Wei National University of Defense Technology Hypersonic Technology Laboratory

We propose an adaptive learning-based optimal control scheme for height-velocity control models considering model uncertainties and external disturbances of hypersonic winged-cone vehicles. The longitudinal nonlinear model is first established and transformed into the control-oriented error equations, and the control scheme is organized by a steady-compensation combination. To overcome and eliminate the impact of model uncertainties and external disturbances, an adaptive radial basis function neural network(RBFNN) is designed by a q-gradient approach. Taking the height-velocity error system with estimated uncertainties into account, the adaptive learning-based optimal tracking control(ALOTC) scheme is proposed by combining the critic-only adaptive dynamic programming(ADP) framework and parameter optimization of system settling time. Furthermore,a novel weight update law is proposed to satisfy the online iteration requirements, and the algorithm convergence and closedloop stability are discussed by the Lyapunov theory. Finally, four simulation cases are provided to prove the effectiveness,accuracy, and robustness of the proposed scheme for the hypersonic longitudinal control system.

关键词： optimal tracking control adaptive dynamic programming RBFNN hypersonic vehicle

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Gut microbial-host-isozymes are new targets for diseases

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Science China(Life Sciences) 2024年第7期67卷 1525-1527页

作者： Zhiwei Zhang kai Wang Changtao Jiang Department of Physiology and Pathophysiology School of Basic Medical SciencesState Key Laboratory of Female Fertility PromotionCenter for Reproductive MedicinePeking UniversityBeijing 100191China Center for Obesity and Metabolic Disease Research School of Basic Medical SciencesState Key Laboratory of Vascular Homeostasis and RemodelingPeking UniversityBeijing 100191China

Gut microbiota can interact with the host through lots of media including small molecular metabolites and proteins(Cani,2019;Fan and Pedersen,2021;Krautkramer et al.,2021).Recently,a new interaction pattern was identified,i.e.,gut microbiota can mimic the function of the host by producing a variety of enzymes with functions homologous to host enzymes.

关键词： al. diseases pattern

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Study on macro and micro shear strength of continuously graded and gap-graded sand

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Particuology 2024年第3期86卷 101-116页

作者： Peiran Zhao Songyu Liu kai Wu School of Transportation Southeast UniversityNanjing210096China

The particle gradation of sand has a significant influence on its shear strength,yet the similarities and differences between the effects of continuous and gap grading have yet to be fully explored.In this study,the discrete element method(DEM)was used to simulate biaxial tests on granular samples that were both continuously graded and gap-graded.The macroscopic analysis revealed that the shear strength of continuously graded sands increases initially and then decreases as the uniformity of particle size distribution decreases.On the other hand,the lack of medium particles in gap-graded sands amplifies the difference in particle size between coarse and fine particles,leading to a decrease in shear strength.Microscopically,both continuous and gap gradings affect the internal packing structure of the particle assembly,which consequently affects particle stress distributions,contact forces,coordination numbers,stress-induced anisotropies,and contact force networks,thus having an impact on the macroscopic shear strength.The global uniformity of particle size distribution was unidirectionally affected by continuous grading,while gap grading had a locally bidirectional influence.These findings provide a better understanding of the effects of particle grading on the macroscopic shear strength of sands.

关键词： Biaxial test Shear strength Particle gradation Discrete element method Micromechanics

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Icariin attenuates vascular endothelial dysfunction by inhibiting inflammation through GPER/Sirt1/HMGB1 signaling pathway in type 1 diabetic rats

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Chinese Journal of Natural Medicines 2024年第4期22卷 293-306页

作者： YAO Wenhui TAO Rongpin WANG kai DING Xuansheng School of Basic Medicine and Clinical Pharmacy China Pharmaceutical UniversityNanjing211198China

Icariin, a flavonoid glycoside, is extracted from Epimedium. This study aimed to investigate the vascular protective effects of icariin in type 1 diabetic rats by inhibiting high-mobility group box 1 (HMGB1)-related inflammation and exploring its potential mechanisms. The impact of icariin on vascular dysfunction was assessed in streptozotocin (STZ)-induced diabetic rats through vascular reactivity studies. Western blotting and immunofluorescence assays were performed to measure the expressions of target proteins. The release of HMGB1 and pro-inflammation cytokines were measured by enzyme-linked immunosorbent assay (ELISA). The results revealed that icariin administration enhanced acetylcholine-induced vasodilation in the aortas of diabetic rats. It also notably reduced the release of pro-inflammatory cytokines, including interleukin-8 (IL-8), IL-6, IL-1β, and tumor necrosis factor-alpha (TNF-α) in diabetic rats and high glucose (HG)-induced human umbilical vein endothelial cells (HUVECs). The results also unveiled that the pro-inflammatory cytokines in the culture medium of HUVECs could be increased by rHMGB1. The increased release of HMGB1 and upregulated expressions of HMGB1-related inflammatory factors, including advanced glycation end products (RAGE), Toll-like receptor 4 (TLR4), and phosphorylated p65 (p-p65) in diabetic rats and HG-induced HUVECs, were remarkably suppressed by icariin. Notably, HMGB1 translocation from the nucleus to the cytoplasm in HUVECs under HG was inhibited by icariin. Meanwhile, icariin could activate G protein-coupled estrogen receptor (GPER) and sirt1. To explore the role of GPER and Sirt1 in the inhibitory effect of icariin on HMGB1 release and HMGB-induced inflammation, GPER inhibitor and Sirt1 inhibitor were used in this study. These inhibitors diminished the effects of icariin on HMGB1 release and HMGB1-induced inflammation. Specifically, the GPER inhibitor also negated the activation of Sirt1 by icariin. These findings suggest that icariin activates GPER and increases the exp

关键词： Icariin Diabetes Inflammation Vascular endothelial dysfunction GPER HMGB1

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