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Article ; Online: Adjustment of infill in transition zone to improve oilfield productivity

Long Xu

E3S Web of Conferences, Vol 375, p

2023 Volume 01024

Abstract: Affected by the high viscosity of crude oil, the large injection-production well spacing, the poor injection condition, and the low oil recovery rate, the overall development effect of transition zone is poor, besides, the low produced degree and the ... ...

Abstract	Affected by the high viscosity of crude oil, the large injection-production well spacing, the poor injection condition, and the low oil recovery rate, the overall development effect of transition zone is poor, besides, the low produced degree and the poor utilization of thin oil layer makes transition zone have some potential excavation. Under the condition that the current conventional measures to improve block development are not clear, it is necessary to further optimize the injection-production system. Based on the principle of “Well pattern rules, Well spacing optimization, Injection-production perfecting, Facilitation of adjustment”, layer combination is thus optimized. This paper analyzes the effect of encryption adjustment and tracking adjustment.
Keywords	transition zone ; produced degree ; encryption adjustment ; Environmental sciences ; GE1-350
Language	English
Publishing date	2023-01-01T00:00:00Z
Publisher	EDP Sciences
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Analysis of atrial remodeling, fibrosis, oxidative stress and insulin resistance levels in patients with atrial fibrillatio

Bang-Long Xu

Journal of Hainan Medical University, Vol 25, Iss 3, Pp 52-

2019 Volume 55

Abstract: Objective: To investigate the analysis of atrial remodeling, fibrosis, oxidative stress and insulin resistance levels in patients with atrial fibrillation. Methods: 60 patients with atrial fibrillation treated in our hospital from December 2016 to ... ...

Abstract	Objective: To investigate the analysis of atrial remodeling, fibrosis, oxidative stress and insulin resistance levels in patients with atrial fibrillation. Methods: 60 patients with atrial fibrillation treated in our hospital from December 2016 to January 2018 were selected as observation group, and 60 healthy persons in the same period were selected as control group. The expression levels of indexes in atrial remodeling [including osteoprotegerin (OPG), nuclear factor kappa beta receptor activating factor ligand (RANKL)], fibrosis [including transforming growth factor beta (TGF-beta) and tumor necrosis factor alpha (TNF-alpha)], oxidative stress [including reactive oxygen species (ROS) and advanced oxidation protein products (AOPP)] and insulin resistance [including human fibroblast growth factor -21 (FGF-21) and omentin-1 (Omentin-1)] were observed and compared between the two groups. Results: The level of Omentin-1 in observation group [(36.75±4.60) ug/L] was significantly lower than that in control group [(87.98±4.43) ug/L] (P<0.05). And there was no significant difference in AOPP level between the observation group and the control group [(13.75±2.13) micromol/ L] (P>0.05). While the levels of atrial remodeling and fibrosis related indexes, ROS and FGF- 21 in the observation group were significantly higher than those in the control group (P<0.05). Conclusions: Understanding the mechanism of atrial remodeling in patients with atrial fibrillation contributes to the prevention and treatment of atrial fibrillation. Patients with atrial fibrillation are not only prone to myocardial fibrosis, but also to oxidative stress and insulin resistance. The relevant indicators should be strengthened in clinical practice, so as to provide evidence for early diagnosis and treatment of the disease.
Keywords	Medicine ; R
Subject code	630
Language	English
Publishing date	2019-02-01T00:00:00Z
Publisher	Editorial Board of Journal of Hainan Medical University
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Polysaccharides from Nitraria retusa Fruit

Lijun Song / Shiqi Liu / Li Zhang / Leiqing Pan / Long Xu

Molecules, Vol 28, Iss 1266, p

Extraction, Purification, Structural Characterization, and Antioxidant Activities

2023 Volume 1266

Abstract: Polysaccharides are important bioactive components of Nitraria retusa fruit (NRF). In this study, the ultrasonic-assisted extraction (UAE) conditions of polysaccharides from Nitraria retusa fruit (NRFPs) were optimized by response surface methodology ( ... ...

Abstract	Polysaccharides are important bioactive components of Nitraria retusa fruit (NRF). In this study, the ultrasonic-assisted extraction (UAE) conditions of polysaccharides from Nitraria retusa fruit (NRFPs) were optimized by response surface methodology (RSM). The structural characteristics and antioxidant activity were investigated. The maximum NRFPs yield of 3.35% was obtained under the following optimal conditions: temperature of 59.5 °C, time of 30.5 min, liquid-to-solid ratio of 19.5 mL/g. Three polysaccharide fractions, NRFP-1 (20.01 kDa), NRFP-2 (28.96 kDa), and NRFP-3 (67.45 kDa), were isolated. Glucose, galactose, and arabinose in different percentages were identified as the primary monosaccharide units. The Fourier transform infrared spectrometer (FT-IR) and nuclear magnetic resonance (NMR) analysis indicated the presence of α- and β-glycosidic bonds in NRFPs. The NRFP-3 exhibited the highest scavenging activities against DPPH, ABTS, -OH free radicals, and Fe +3 -reducing activity.
Keywords	Nitraria retusa fruit ; polysaccharides ; ultrasonic-assisted extraction ; structure characterization ; antioxidant activity ; Organic chemistry ; QD241-441
Subject code	540
Language	English
Publishing date	2023-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Finite time observer‐based super‐twisting sliding mode control for vehicle platoons with guaranteed strong string stability

Qian Chen / Long Xu / Yang Zhou / Shihua Li

IET Intelligent Transport Systems, Vol 16, Iss 12, Pp 1726-

2022 Volume 1737

Abstract: Abstract This paper presents a finite time disturbance observer (FTDO)‐based super‐twisting sliding mode control (SMC) structure for a vehicle platoon system with a focus on parameter uncertainties as well as external disturbances. In order to compensate ...

Abstract	Abstract This paper presents a finite time disturbance observer (FTDO)‐based super‐twisting sliding mode control (SMC) structure for a vehicle platoon system with a focus on parameter uncertainties as well as external disturbances. In order to compensate the parameter uncertainties and external disturbances, a composite FTDO‐based super twisting SMC method is developed under zero initial spacing deviations, where the parameter uncertainties, external disturbances, and the preceding vehicle's acceleration are estimated as a lumped disturbance by employing an FTDO. Benefiting from the FTDO, the estimation error dynamics is stable in finite time. Different from the existing SMC‐based achievements, the continuity of the control signals can be achieved, which avoids the undesirable chattering phenomenon in the existing SMC‐based works. Leveraging an FTDO, the preceding vehicle's acceleration information is not required, which enables the proposed control method to exploit a unidirectional information flow topology. Thus, it can reduce communication burden compared with bidirectional information flow topologies. Then, an improved time gap policy is employed to extend the developed control scheme to a more general case with nonzero initial spacing deviations. In addition, the individual stability of each vehicle is rigorously analyzed by resorting to the Lyapunov stability theory. Furthermore, the strong string stability of the whole vehicle platoon is derived with the help of the Laplace transform. Finally, numerical simulations are conducted to illustrate the effectiveness and applicability of the developed control scheme.
Keywords	Transportation engineering ; TA1001-1280 ; Electronic computers. Computer science ; QA75.5-76.95
Subject code	629
Language	English
Publishing date	2022-12-01T00:00:00Z
Publisher	Wiley
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Complementary Segmentation of Primary Video Objects with Reversible Flows

Junjie Wu / Jia Li / Long Xu

Applied Sciences, Vol 12, Iss 7781, p

2022 Volume 7781

Abstract: Segmenting primary objects in a video is an important yet challenging problem in intelligent video surveillance, as it exhibits various levels of foreground/background ambiguities. To reduce such ambiguities, we propose a novel formulation via exploiting ...

Abstract	Segmenting primary objects in a video is an important yet challenging problem in intelligent video surveillance, as it exhibits various levels of foreground/background ambiguities. To reduce such ambiguities, we propose a novel formulation via exploiting foreground and background context as well as their complementary constraint. Under this formulation, a unified objective function is further defined to encode each cue. For implementation, we design a complementary segmentation network (CSNet) with two separate branches, which can simultaneously encode the foreground and background information along with joint spatial constraints. The CSNet is trained on massive images with manually annotated salient objects in an end-to-end manner. By applying CSNet on each video frame, the spatial foreground and background maps can be initialized. To enforce temporal consistency effectively and efficiently, we divide each frame into superpixels and construct a neighborhood reversible flow that reflects the most reliable temporal correspondences between superpixels in far-away frames. With such a flow, the initialized foregroundness and backgroundness can be propagated along the temporal dimension so that primary video objects gradually pop out and distractors are well suppressed. Extensive experimental results on three video datasets show that the proposed approach achieves impressive performance in comparisons with 22 state-of-the-art models.
Keywords	primary object segmentation ; video ; objective function ; complementary CNNs ; neighborhood reversibility ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	004
Language	English
Publishing date	2022-08-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Knowledge search, knowledge integration and enterprise breakthrough innovation under the characteristics of innovation ecosystem network

Yanli Zhang / Dantong Wang / Long Xu

PLoS ONE, Vol 16, Iss 12, p e

The empirical evidence from enterprises in Beijing-Tianjin-Hebei region.

2021 Volume 0261558

Abstract: Enterprises acquire heterogeneous knowledge through external knowledge search and adapt to the change of external environment, which is of great significance to enterprise breakthrough innovation. This paper takes the innovation ecosystem as the boundary ...

Abstract	Enterprises acquire heterogeneous knowledge through external knowledge search and adapt to the change of external environment, which is of great significance to enterprise breakthrough innovation. This paper takes the innovation ecosystem as the boundary of the research paradigm. Based on innovation ecosystem theory, knowledge management theory and enterprise innovation theory, this paper constructs a moderated mediation model of the enterprise knowledge search, knowledge integration and breakthrough innovation under the characteristics of innovation ecosystem network. This model is tested on the survey data of 344 technology enterprise and manufacturing industries including R&D departments in the Beijing-Tianjin-Hebei region. The research results show that: knowledge integration plays part of the intermediary role between knowledge search and enterprise breakthrough innovation; the larger the network scale, the stronger the network connection, the stronger the intermediary role of knowledge integration on the relationship between knowledge search and enterprise breakthrough innovation. The research results reveal the important role of the innovation ecosystem in enterprise breakthrough innovation. At the same time, the research on knowledge search and enterprise breakthrough innovation should consider the network characteristics of innovation ecosystem and the ability of enterprise knowledge integration.
Keywords	Medicine ; R ; Science ; Q
Subject code	650
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Optimization of Enterprise Labor Resource Allocation Based on Quality Optimization Model

Gaoyang Liang / Long Xu / Liang Chen

Complexity, Vol

2021 Volume 2021

Abstract: Companies take project-based management as their organizational strategy, and project quality assurance plays a vital role in improving customer satisfaction and enhancing corporate image. Starting from the perspective of optimizing project quality, this ...

Abstract	Companies take project-based management as their organizational strategy, and project quality assurance plays a vital role in improving customer satisfaction and enhancing corporate image. Starting from the perspective of optimizing project quality, this paper assigns different quality influencing factors to each project and each task of the project, divides the labor resources shared by multiple projects in the enterprise according to the skill level, and transforms the problem of project quality optimization. The problem of the highest skill level of labor resources allocated to all projects of the enterprise is designed, and algorithms are designed to achieve the optimization of project quality through the optimal allocation of labor resources. The various links in this article are closely related to form a comprehensive, scientific, and systematic research system for optimal human resource allocation, human resource management, and development. Finally, case analysis is used to confirm the usability of the model and provide a quantitative method and perspective for project-oriented companies to allocate workforce.
Keywords	Electronic computers. Computer science ; QA75.5-76.95
Subject code	650
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	Hindawi-Wiley
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Robust Classification Model for Diabetic Retinopathy Based on the Contrastive Learning Method with a Convolutional Neural Network

Xinxing Feng / Shuai Zhang / Long Xu / Xin Huang / Yanyan Chen

Applied Sciences, Vol 12, Iss 12071, p

2022 Volume 12071

Abstract: Diabetic retinopathy is one of the most common microvascular complications of diabetes. Early detection and treatment can effectively reduce the risk. Hence, a robust computer-aided diagnosis model is important. Based on the labeled fundus images, we ... ...

Abstract	Diabetic retinopathy is one of the most common microvascular complications of diabetes. Early detection and treatment can effectively reduce the risk. Hence, a robust computer-aided diagnosis model is important. Based on the labeled fundus images, we build a binary classification model based on ResNet-18 and transfer learning and, more importantly, improve the robustness of the model through supervised contrastive learning. The model is tested with different learning rates and data augmentation methods. The standard deviations of the multiple test results decrease from 4.11 to 0.15 for different learning rates and from 1.53 to 0.18 for different data augmentation methods. In addition, the supervised contrastive learning method also improves the average accuracy of the model, which increases from 80.7% to 86.5%.
Keywords	supervised contrastive learning ; diabetic retinopathy classification ; convolutional neural network ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	006
Language	English
Publishing date	2022-11-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Solvated Ion Intercalation in Graphite

Jooha Park / Zheng-Long Xu / Kisuk Kang

Frontiers in Chemistry, Vol

Sodium and Beyond

2020 Volume 8

Abstract: Reversible intercalation of guest ions in graphite is the key feature utilized in modern battery technology. In particular, the capability of Li-ion insertion into graphite enabled the successful launch of commercial Li-ion batteries 30 years ago. On the ...

Abstract	Reversible intercalation of guest ions in graphite is the key feature utilized in modern battery technology. In particular, the capability of Li-ion insertion into graphite enabled the successful launch of commercial Li-ion batteries 30 years ago. On the road to explore graphite as a universal anode for post Li-ion batteries, the conventional intercalation chemistry is being revisited, and recent findings indicate that an alternative intercalation chemistry involving the insertion of solvated ions, designated as co-intercalation, could overcome some of the obstacles presented by the conventional intercalation of graphite. As an example, the intercalation of Na ions into graphite for Na-ion batteries has been perceived as being thermodynamically impossible; however, recent work has revealed that a large amount of Na ions can be reversibly inserted in graphite through solvated-Na-ion co-intercalation reactions. More recently, it has been extensively demonstrated that with appropriate electrolyte selection, not only Na ions but also other ions such as Li, K, Mg, and Ca ions can be co-intercalated into a graphite electrode, resulting in high capacities and power capabilities. The co-intercalation reaction shares a lot in common with the conventional intercalation chemistry but also differs in many respects, which has attracted tremendous research efforts in terms of both fundamentals and practical applications. Herein, we aim to review the progress made in understanding the solvated-ion intercalation mechanisms in graphite and to comprehensively summarize the state-of-the-art achievements by surveying the correlations among the guest ions, co-intercalation conditions, and electrochemical performance of batteries. In addition, the advantages and challenges related to the practical application of graphite undergoing co-intercalation reactions are presented.
Keywords	graphite ; co-intercalation ; anode materials ; Li-ion batteries ; Na-ion batteries ; K-ion batteries ; Chemistry ; QD1-999
Subject code	540
Language	English
Publishing date	2020-05-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Does the board’s on-site decision inhibit over-investment

Xiaofei Shi / Fei Zhao / Long Xu / Na Bian / Fengfei Wang

PLoS ONE, Vol 16, Iss

2021 Volume 8

Abstract: It is an effective expansion of the research on the Board of Directors to do the research based on different board meeting forms and their effects sampling A-share companies listed in 2007–2017, the article empirically tests the impact of the times of ... ...

Abstract	It is an effective expansion of the research on the Board of Directors to do the research based on different board meeting forms and their effects sampling A-share companies listed in 2007–2017, the article empirically tests the impact of the times of board meetings, the proportion of on-site board meetings on listed companies’ over-investment. Consequently and significantly, the times of board meetings is positively correlated with over-investment, while the proportion of on-site board meetings is negatively correlated with over-investment. That is, the on-site meeting for the Board decision-making will better inhibit the enterprises’ over-investment behaviors. Further research shows that when there is a controlling shareholder in the company or in a dual position, the on-site board meeting no longer has a significant inhibitory effect on over-investment. By research on the independence of the Board of Directors, it is found that when selecting on-site board decision-making, the existence of independent directors has an over-investment suppression effect, and the higher the proportion of independent directors, the more obvious the inhibitory effect is. The samples are divided into state-owned enterprises and private enterprises, the study found that when choosing on-site board meetings, state-owned enterprises have a greater inhibitory effect on over-investment than private enterprises. The findings of this study will enrich the research of the board meeting and provide a new testing method for the relevant research of the Board of Directors.
Keywords	Medicine ; R ; Science ; Q
Subject code	650
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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