检索结果-南通市图书馆

Communications on Applied Mathematics and Computation 2024年第1期6卷 311-324页

作者： Bo Dong wei wang Department of Mathematics University of Massachusetts DartmouthNorth DartmouthMA02747USA Department of Mathematics and Statistics Florida International UniversityMiamiFL33199USA

In this paper,numerical experiments are carried out to investigate the impact of penalty parameters in the numerical traces on the resonance errors of high-order multiscale discontinuous Galerkin(DG)methods(Dong et al.in J Sci Comput 66:321–345,2016;Dong and wang in J Comput Appl Math 380:1–11,2020)for a one-dimensional stationary Schrödinger equation.Previous work showed that penalty parameters were required to be positive in error analysis,but the methods with zero penalty parameters worked fine in numerical simulations on coarse meshes.In this work,by performing extensive numerical experiments,we discover that zero penalty parameters lead to resonance errors in the multiscale DG methods,and taking positive penalty parameters can effectively reduce resonance errors and make the matrix in the global linear system have better condition numbers.

关键词： Discontinuous Galerkin(DG)method Multiscale method Resonance errors One-dimensional Schrödinger equation

Quaternion-Based Adaptive Trajectory Tracking Control of a Rotor-Missile with Unknown Parameters Identification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第1期31卷 375-386页

作者： Jie Zhao Zhongjiao Shi Yuchen wang wei wang Beijing Institute of Technology Beijing 100081China

This paper investigates the adaptive trajectory tracking control problem and the unknown parameter identification problem of a class of rotor-missiles with parametric system uncertainties.First,considering the uncertainty of structural and aerodynamic parameters,the six-degree-of-freedom(6Do F) nonlinear equations describing the position and attitude dynamics of the rotor-missile are established,respectively,in the inertial and body-fixed reference frames.Next,a hierarchical adaptive trajectory tracking controller that can guarantee closed-loop stability is proposed according to the cascade characteristics of the 6Do F dynamics.Then,a memory-augmented update rule of unknown parameters is proposed by integrating all historical data of the regression matrix.As long as the finitely excited condition is satisfied,the precise identification of unknown parameters can be achieved.Finally,the validity of the proposed trajectory tracking controller and the parameter identification method is proved through Lyapunov stability theory and numerical simulations.

关键词： Rotor-missile Adaptive control Parameter identification Quaternion control

Repeated inoculation with rumen fluid accelerates the rumen bacterial transition with no benefit on production performance in postpartum Holstein dairy cows

在线全文

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2024年第2期15卷 795-811页

作者： Fanlin Kong Feiran wang Yijia Zhang Shuo wang wei wang Shengli Li Beijing Engineering Technology Research Center of Raw Milk Quality and Safety Control State Key Laboratory of Animal NutritionDepartment of Animal Nutrition and Feed ScienceCollege of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193PR China College of Veterinary Medicine Nanjing Agricultural UniversityNanjingJiangsu 210095PR China

Background The dairy cow’s postpartum period is characterized by dramatic physiological changes,therefore imposing severe challenges on the animal for maintaining health and milk output.The dynamics of the ruminal microbiota are also tremendous and may play a crucial role in lactation launch.We aim to investigate the potential benefits of early microbial intervention by fresh rumen microbiota transplantation(RMT)and sterile RMT in postpartum dairy cows.Twelve fistulated peak-lactation dairy cows were selected to be the donors for rumen fluid collection.Thirty postpartum cows were divided into 3 groups as the transplantation receptors respectively receiving 10 L fresh rumen fluid(FR),10 L sterile rumen fluid(SR),or 10 L saline(CON)during 3 d after calving.Results Production performance,plasma indices,plasma lipidome,ruminal microbiome,and liver transcriptome were recorded.After fresh and sterile RMT,we found that the molar proportion of propionic acid was increased on d 7 in the FR and SR groups and the bacterial composition was also significantly changed when compared with the CON group.A similarity analysis showed that the similarities between the CON group and FR or SR group on d 7 were 48.40%or 47.85%,whereas the similarities between microbiota on d 7 and 21 in the FR and SR groups were 68.34%or 66.85%.Dry matter intake and feed efficiency were not affected by treatments.Plasmaβ-hydroxybutyrate concentration in the FR group was decreased and significantly different lipids mainly included phosphatidylcholine and lysophosphatidylcholine containing polyunsaturated fatty acids.Hepatic transcriptomics analysis indicated acutephase response pathways were upregulated in the SR group.Conclusions Our study suggests that RMT can shorten the transition process of the ruminal microbiota of postpartum dairy cows with no benefit on dry matter intake or feed efficiency.Inoculation with rumen fluid may not be a useful approach to promote the recovery of postpartum dairy cows.

关键词： Dairy cow Lipidomics Liver Rumen microbiota transplantation Transition period

Steady-state Voltage Security-constrained Optimal Frequency Control for Weak HVDC Sending-end AC Power Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 658-669页

作者： Qiangqiang wang Liangzhong Yao Jian Xu Yuping Zheng wei Li wei wang School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China Hubei Engineering and Technology Research Center for AC/DC Intelligent Distribution Network(Wuhan University) Wuhan 430072China State Key Laboratory of Smart Grid Protection and Control NARI Group Corporation(State Grid Electric Power Research Institute)Nanjing 211106China

Due to the fact that a high share of renewable energy sources(RESs)are connected to high-voltage direct current(HVDC)sending-end AC power systems,the voltage and frequency regulation capabilities of HVDC sending-end AC power systems have diminished.This has resulted in potential system operating problems such as overvoltage and overfrequency,which occur simultaneously when block faults exist in the HVDC link.In this study,a steady-state voltage security-constrained optimal frequency control method for weak HVDC sending-end AC power systems is proposed.The integrated virtual inertia control of RESs is employed for system frequency regulation.Additional dynamic reactive power compensation devices are utilized to control the voltage of all nodes meet voltage security constraints.Then,an optimization model that simultaneously considers the frequency and steady-state voltage security constraints for weak HVDC sending-end AC power systems is established.The optimal control scheme with the minimum total cost of generation tripping and additional dynamic reactive power compensation required is obtained through the optimization solution.Simulations are conducted on a modified IEEE 9-bus test system and practical Qing-Yu line commutated converter based HVDC(LCC-HVDC)sending-end AC power system to verify the effectiveness of the proposed method.

关键词： Renewable energy source(RES) high-voltage direct current(HVDC) AC power system optimal frequency control steady-state voltage security dynamic reactive power compensation

Comprehensive Relation Modelling for Image Paragraph Generation

在线全文

学校读者我要写书评

暂无评论

Machine Intelligence Research 2024年第2期21卷 369-382页

作者： Xianglu Zhu Zhang Zhang wei wang Zilei wang Automation Department University of Science and Technology of ChinaHefei 230027China Center for Research on Intelligent Perception and Computing National Laboratory of Pattern RecognitionInstitute of AutomationChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100864China

Image paragraph generation aims to generate a long description composed of multiple sentences,which is different from traditional image captioning containing only one sentence.Most of previous methods are dedicated to extracting rich features from image regions,and ignore modelling the visual relationships.In this paper,we propose a novel method to generate a paragraph by modelling visual relationships comprehensively.First,we parse an image into a scene graph,where each node represents a specific object and each edge denotes the relationship between two objects.Second,we enrich the object features by implicitly encoding visual relationships through a graph convolutional network(GCN).We further explore high-order relations between different relation features using another graph convolutional network.In addition,we obtain the linguistic features by projecting the predicted object labels and their relationships into a semantic embedding space.With these features,we present an attention-based topic generation network to select relevant features and produce a set of topic vectors,which are then utilized to generate multiple sentences.We evaluate the proposed method on the Stanford image-paragraph dataset which is currently the only available dataset for image paragraph generation,and our method achieves competitive performance in comparison with other state-of-the-art(SOTA)methods.

关键词： Image paragraph generation visual relationship scene graph graph convolutional network(GCN) long short-term memory

Effect of hafnium and molybdenum addition on inclusion characteristics in Co-based dual-phase high-entropy alloys

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1639-1650页

作者： Yong wang wei wang Joo Hyun Park wangzhong Mu Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education&Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081China Department of Materials Science and Engineering KTH Royal Institute of TechnologySE-10044StockholmSweden Department of Chemical Engineering Northeast Electric Power UniversityJilin 132012China Department of Materials Science and Chemical Engineering Hanyang UniversityAnsan 15588Korea Engineering Materials Division of Materials ScienceDepartment of Engineering Science and MathematicsLuleå University of Technology97187 LuleåSweden

Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature applications.In this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5)Mn_(7.5)Ni_(7.5)(at%)was chosen.The refractory metallic elements hafnium(Hf)and molybdenum(Mo)were added in small amounts(1.5at%)because of their well-known positive effects on high-temperature properties.Inclusion characteristics were comprehensively explored by using a two-dimensional cross-sectional method and extracted by using a three-dimensional electrolytic extraction method.The results revealed that the addition of Hf can reduce Al_(2)O_(3)inclusions and lead to the formation of more stable Hf-rich inclusions as the main phase.Mo addition cannot influence the inclusion type but could influence the inclusion characteristics by affecting the physical parameters of the HEA melt.The calculated coagulation coefficient and collision rate of Al_(2)O_(3)inclusions were higher than those of HfO_(2)inclusions,but the inclusion amount played a larger role in the agglomeration behavior of HfO_(2)and Al_(2)O_(3)inclusions.The impurity level and active elements in HEAs were the crucial factors affecting inclusion formation.

关键词： high-entropy alloy non-metallic inclusion agglomeration thermodynamics alloying

A brief review of tribological properties for black phosphorus

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第5期12卷 823-844页

作者： Fanfan LV wei wang Jinjin LI Yuan GAO Kuaishe wang College of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an710055China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing10084China

Black phosphorus (BP) is a new class of two-dimensional (2D) layered material, which shows the unanticipated characteristics in many aspects including electronics, transistors, sensors, energy storage, batteries, photocatalysis, and other applications due to its high charge carrier mobility, tunable direct bandgap, and unique in-plane anisotropic structure. In addition, BP has drawn tremendous attention in the field of tribology due to the low shear strength, the layered structure, and the weak connected force between the layers by van der Waals interaction. In recent years, many significant progresses have been made in experimental studies on BP materials as solid lubricants or lubrication additives. This work offers a review of researching regarding the tribological properties of BP. Moreover, the lubrication mechanisms of BP as the lubrication additive including the formation of the tribo-film, micro-bearing effect, and self-repair performance are also summarized. Finally, the current challenges and prospects of BP material as lubricant are proposed.

关键词： black phosphorus(BP) two-dimensional(2D)layered material lubrication additives tribological mechanisms

Drug repurposing screening and mechanism analysis based on human colorectal cancer organoids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Protein & Cell 2024年第4期15卷 285-304页

作者： Yunuo Mao wei wang Jingwei Yang Xin Zhou Yongqu Lu Junpeng Gao Xiao wang Lu Wen wei Fu Fuchou Tang School of Life Sciences Biomedical Pioneering Innovation CenterDepartment of General SurgeryThird HospitalPeking UniversityBeijing 100871China Beijing Advanced Innovation Center for Genomics(ICG) Ministry of Education Key Laboratory of Cell Proliferation and DifferentiationBeijing 100871China Peking-Tsinghua Center for Life Sciences Peking UniversityBeijing 100871China Peking University Third Hospital Cancer Center Beijing 100871China The Research Center of Stem Cell and Regenerative Medicine School of Basic Medical SciencesCheeloo College of MedicineShandong UniversityJinan 250012China

Colorectal cancer(CRC)is a highly heterogeneous cancer and exploring novel therapeutic options is a pressing issue that needs to be addressed.Here,we established human CRC tumor-derived organoids that well represent both morphological and molecular heterogeneities of original tumors.To efficiently identify repurposed drugs for CRC,we developed a robust organoid-based drug screening system.By combining the repurposed drug library and computation-based drug prediction,335 drugs were tested and 34 drugs with anti-CRC effects were identified.More importantly,we conducted a detailed transcriptome analysis of drug responses and divided the drug response signatures into five representative patterns:differentiation induction,growth inhibition,metabolism inhibition,immune response promotion,and cell cycle inhibition.The anticancer activities of drug candidates were further validated in the established patient-derived organoids-based xenograft(PDOX)system in vivo.We found that fedratinib,trametinib,and bortezomib exhibited effective anticancer effects.Furthermore,the concordance and discordance of drug response signatures between organoids in vitro and pairwise PDOX in vivo were evaluated.Our study offers an innovative approach for drug discovery,and the representative transcriptome features of drug responses provide valuable resources for developing novel clinical treatments for CRC.

关键词： colorectal cancer organoids drug repurposing patient-derived organoids-based xenograft mechanism of action

Identification of an immune-related gene signature for predicting prognosis and immunotherapy efficacy in liver cancer via cell-cell communication

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第11期30卷 1609-1620页

作者： Jun-Tao Li Hong-Mei Zhang wei wang Dong-Qing wei College of Mathematics and Information Science Henan Normal UniversityXinxiang 453007Henan ProvinceChina College of Computer and Information Engineering Henan Normal UniversityXinxiang 453007Henan ProvinceChina State Key Laboratory of Microbial Metabolism and School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai 200240China

BACKGROUND Liver cancer is one of the deadliest malignant tumors worldwide.Immunotherapy has provided hope to patients with advanced liver cancer,but only a small fraction of patients benefit from this treatment due to individual differences.Identifying immune-related gene signatures in liver cancer patients not only aids physicians in cancer diagnosis but also offers personalized treatment strategies,thereby improving patient survival rates.Although several methods have been developed to predict the prognosis and immunotherapeutic efficacy in patients with liver cancer,the impact of cell-cell interactions in the tumor microenvir-onment has not been adequately considered.AIM To identify immune-related gene signals for predicting liver cancer prognosis and immunotherapy efficacy.METHODS Cell grouping and cell-cell communication analysis were performed on single-cell RNA-sequencing data to identify highly active cell groups in immune-related pathways.Highly active immune cells were identified by intersecting the highly active cell groups with B cells and T cells.The significantly differentially expressed genes between highly active immune cells and other cells were subsequently selected as features,and a least absolute shrinkage and selection operator(LASSO)regression model was constructed to screen for diagnostic-related features.Fourteen genes that were selected more than 5 times in 10 LASSO regression experiments were included in a multivariable Cox regression model.Finally,3 genes(stathmin 1,cofilin 1,and C-C chemokine ligand 5)significantly associated with survival were identified and used to construct an immune-related gene signature.RESULTS The immune-related gene signature composed of stathmin 1,cofilin 1,and C-C chemokine ligand 5 was identified through cell-cell communication.The effectiveness of the identified gene signature was validated based on experi-mental results of predictive immunotherapy response,tumor mutation burden analysis,immune cell infiltration analysis,survival analysis,and expression an

关键词： Liver cancer Cell-cell communication Gene signature Prognosis Immunotherapy Single-cell RNA sequencing

Nanofluidic memristor based on the elastic deformation of nanopores with nanoparticle adsorption

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第4期11卷 46-54页

作者： Xi Zhou Yuanyuan Zong Yongchang wang Miao Sun Deli Shi wei wang Guanghua Du Yanbo Xie Department of Chemistry and Chemical Engineering Northwestern Polytechnical University School of Physical Science and Technology Northwestern Polytechnical University School of Aeronautics and Institute of Extreme Mechanics Northwestern Polytechnical University Institute of Modern Physics Chinese Academy of Sciences

The memristor is the building block of neuromorphic computing. We report a new type of nanofluidic memristor based on the principle of elastic strain on polymer nanopores. With nanoparticles absorbed at the wall of a single conical polymer nanopore, we find a pinched hysteresis of the current within a scanning frequency range of 0.01–0.1 Hz, switching to a diode below 0.01 Hz and a resistor above 0.1 Hz. We attribute the current hysteresis to the elastic strain at the tip side of the nanopore, caused by electrical force on the particles adsorbed at the inner wall surface. Our simulation and analytical equations match well with experimental results, with a phase diagram for predicting the system transitions. We demonstrate the plasticity of our nanofluidic memristor to be similar to a biological synapse. Our findings pave a new way for ionic neuromorphic computing using nanofluidic memristors.

关键词： nanofluidics memristor neurocomputing elastic deformation