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中国海洋工程:英文版 2023年第4期37卷 588-597页

作者： Pankaj R.JAISWAL Rahul Iyer KUMAR Richard TRUMPER wim DE WAELE Soete Laboratory Department of ElectromechanicalSystems and Metal Engineering(EMSME)Ghent UniversityGhent 9052Belgium BAE systems London SW1Y 5ADUnited Kingdom

This paper reports an experimental study of the mechanical response to tensile and compressive force of large scale steel to composite joints adhesively bonded with a thin layer of vinylester *** one specimen,the length of the reinforcing fibres in contact with the steel substrate has been reduced by saw cutting at both ends of the *** damaged specimen and four intact specimens were subjected to quasi-static tensile testing;six specimens were used for compression *** strain distribution at the composite surface and at the steel to hardwood connection of the specimen was monitored by digital image correlation(DIC).DIC allowed identifying the onset of damage in the tensile tested joints near the interface of the composite layer and the steel-hardwood *** tensile and compression tested specimens failed due to significant peel strain concentration at the composite near the connection of steel and *** average strength of a specimen tested in compression was about 66%higher than the average strength of a specimen tested in *** strain concentration zone in the damaged specimen was away from the introduced saw *** a result the damaged and intact tensile specimens showed the same failure strength and *** specimens failed by adhesive failure between the composite-hardwood interface.

关键词： vinylester resin multi-material joint strain damage digital image correlation.

Controlling postoperative ileus by vagal activation

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World Journal of Gastroenterology 2010年第14期16卷 1683-1687页

作者： Tim Lubbers wim Buurman Misha Luyer Department of Surgery NUTRIM School for Nutrition Toxicology and Metabolism Maastricht University Medical Center 6200 MD Maastricht The Netherlands Department of Surgery Orbis Medical Center 6162 BG Sittard The Netherlands

Postoperative ileus is a frequently occurring surgical complication, leading to increased morbidity and hospital stay. Abdominal surgical interventions are known to result in a protracted cessation of bowel movement. Activation of inhibitory neural pathways by nociceptive stimuli leads to an inhibition of propulsive activity, which resolves shortly after closure of the abdomen. The subsequent formation of an inflammatory infiltrate in the muscular layers of the intestine results in a more prolonged phase of ileus. Over the last decade, clinical strategies focusing on reduction of surgical stress and promoting postoperative recovery have improved the course of postoperative ileus. Additionally, recent experimental evidence implicated antiinflammatory interventions, such as vagal stimulation, as potential targets to treat postoperative ileus and reduce the period of intestinal hypomotility. Activation of nicotinic receptors on inflammatory cells by vagal input attenuates inflammation and promotes gastrointestinal motility in experimental models of ileus. A novel physiologicalintervention to activate this neuroimmune pathway is enteral administration of lipid-rich nutrition. Perioperative administration of lipid-rich nutrition reduced manipulation-induced local inflammation of the intestine and accelerated recovery of bowel movement. The application of safe and easy to use antiinflammatory interventions, together with the current multimodal approach, could reduce postoperative ileus to an absolute minimum and shorten hospital stay.

关键词： Postoperative ileus Inflammation Vagus Nutritional antiinflammatory pathway

Creating adaptive farm typologies using Naive Bayesian classification

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Information Processing in Agriculture 2017年第3期4卷 220-227页

作者： wim Paas Jeroen C.J.Groot Farming Systems Ecology Wageningen University&ResearchP.O.Box 4306700 AK WageningenThe Netherlands Plant Production Systems Wageningen University&ResearchP.O.Box 4306700 AK WageningenThe Netherlands

The applicability of statistical typologies that capture farming systems diversity in innovation and development projects would increase if their adaptability would be enhanced,so that newly encountered farms can be classified and used to update the *** this paper we propose Naıve Bayesian(NB)classification as a method to allocate farms to types by using only a few variables,thus allowing the addition of new entries to a *** show for two example datasets that the performance of NB classification is already acceptable when 50% of the original survey dataset to construct the typology is used for training the NB *** our datasets,the performance of Naı¨ve Bayesian classification was improved when probabilities for observations to belong to multiple types were used,requiring a sample size of 30% of the survey *** on the results in this paper,we argue that NB classification is a powerful and promising statistical approach to increase the adaptability and usability of farm typologies.

关键词： Farming systems Data distributions Clustering Diversity

Stochastic collocation for device-level variability analysis in integrated photonics

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Photonics Research 2016年第2期4卷 93-100页

作者： Yufei Xing Domenico Spina Ang Li Tom Dhaene wim Bogaerts Photonics Research Group Department of Information Technology Center for Nano and BiophotonicsGhent University imec Department of Information Technology Internet Based Communication Networks and Services (IBCN)Ghent University iMinds Luceda Photonics

We demonstrate the use of stochastic collocation to assess the performance of photonic devices under the effect of uncertainty. This approach combines high accuracy and efficiency in analyzing device variability with the ease of implementation of sampling-based methods. Its flexibility makes it suitable to be applied to a large range of photonic devices. We compare the stochastic collocation method with a Monte Carlo technique on a numerical analysis of the variability in silicon directional couplers.

关键词： Stochastic collocation for device-level variability analysis in integrated photonics

Accurate extraction of fabricated geometry using optical measurement

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Photonics Research 2018年第11期6卷 1008-1020页

作者： YUFEI XING JIAXING DONG SARVAGYA DWIVEDI UMAR KHAN wim BOGAERTS Photonics Research Group Ghent University-IMEC Center of Nano and Biophotonics Ghent Belgium Electrical and Computer Engineering Department University of California Santa Barbara Santa Barbara

We experimentally demonstrate extraction of silicon waveguide geometry with subnanometer accuracy using optical measurements. Effective and group indices of silicon-on-insulator(SOI) waveguides are extracted from the optical measurements. An accurate model linking the geometry of an SOI waveguide to its effective and group indices is used to extract the linewidths and thicknesses within respective errors of 0.37 and0.26 nm on a die fabricated by IMEC multiproject wafer services. A detailed analysis of the setting of the bounds for the effective and group indices is presented to get the right extraction with improved accuracy.

关键词： MZI Accurate extraction measurement

The effect of host plants on genotype variability in fitness and honeydew composition of Aphis fabae

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Insect Science 2017年第5期24卷 781-788页

作者： Sharon Schillewaert Amelie Vantaux wim Van den Ende Tom Wenseleers Laboratory of Socioecology and Social Evolution Biology Department Zoological Institute University of Leuven Leuven Belgium Institut Pasteur du Cambodge Unite d'Epidemiologie Moleculaire du Paludisme Phnom Penh Cambodia Laboratory of Molecular Plant Biology Biology Department University of Leuven Leuven Belgium

Aphid species can be polyphagous, feeding on multiple host plants across genera. As host plant species can have large variation in their phloem composition, this can affect aphid fitness and honeydew composition. Previous research showed significant intraspecific genotype variation in the composition of the honeydew carbohydrates of the black bean aphid Aphis fabae, with the ant attractant trisaccharide melezitose showing especially large variation across different genotypes. In this study, we test if variation in melezitose and carbohydrate composition of aphid honeydew could be linked to the adap- tation of specific aphid genotypes to particular host plants. To this end, 4 high and 5 low melezitose secreting genotypes of the black bean aphid Aphisfabae were reared on 4 com- mon host plants： broad bean, goosefoot, beet, and poppy. The carbohydrate composition, and in particular melezitose secretion, showed important aphid genotype and host plant in- teractions, with some genotypes being high melezitose secreting on 1 host plant but not on another. However, the interaction effects were not paralleled in the fitness measurements, even though there were significant differences in the average fitness across the different host plants. On the whole, this study demonstrates that aphid honeydew composition is influenced by complex herbivore-plant interactions. We discuss the relevance of these findings in the context of ant-aphid mutualisms and adaptive specialization in aphids.

关键词： aphids Aphis fabae ecological specialization fitness honeydew hostplants Melezitose polyphagous

Dynamic Stability Analysis of Linear Time-varying Systems via an Extended Modal Identification Approach

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Chinese Journal of Mechanical Engineering 2017年第2期30卷 459-471页

作者： Zhisai MA Li LIU Sida ZHOU Frank NAETS Ward HEYLEN wim DESMET School of Aerospace Engineering Beijing Institute of Technology Department of Mechanical Engineering KU Leuven

The problem of linear time-varying（LTV） system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system modal analysis under the ＂frozen-time＂ assumption are not able to determine the dynamic stability of LTV systems. Time-dependent state space representations of LTV systems are first introduced, and the corresponding modal analysis theories are subsequently presented via a stabilitypreserving state transformation. The time-varying modes of LTV systems are extended in terms of uniqueness, and are further interpreted to determine the system＇s stability. An extended modal identification is proposed to estimate the time-varying modes, consisting of the estimation of the state transition matrix via a subspace-based method and the extraction of the time-varying modes by the QR decomposition. The proposed approach is numerically validated by three numerical cases, and is experimentally validated by a coupled moving-mass simply supported beam exper- imental case. The proposed approach is capable of accurately estimating the time-varying modes, and provides anew way to determine the dynamic stability of LTV systems by using the estimated time-varying modes.

关键词： Linear time·varying systems · Extended modal identification · Dynamic stability analysis · Time·varying modes

Numerical modeling of a linear photonic system for accurate and efficient time-domain simulations

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Photonics Research 2018年第6期6卷 560-573页

作者： YINGHAO YE DOMENICO SPINA YUFEI XING wim BOGAERTS TOM DHAENE IDLab Department of Information TechnologyGhent University-imec Photonics Research Group Department of Information TechnologyGhent University-imec

In this paper, a novel modeling and simulation method for general linear, time-invariant, passive photonic devices and circuits is proposed. This technique, starting from the scattering parameters of the photonic system under study, builds a baseband equivalent state-space model that splits the optical carrier frequency and operates at baseband, thereby significantly reducing the modeling and simulation complexity without losing ***, it is possible to analytically reconstruct the port signals of the photonic system under study starting from the time-domain simulation of the corresponding baseband equivalent model. However, such equivalent models are complex-valued systems and, in this scenario, the conventional passivity constraints are not applicable anymore. Hence, the passivity constraints for scattering parameters and state-space models of baseband equivalent systems are presented, which are essential for time-domain simulations. Three suitable examples demonstrate the feasibility, accuracy, and efficiency of the proposed method.

关键词： Wavelength filtering devices Systems design Photonic integrated circuits

Structural optimization of patient-specific temporomandibular joint replacement implants for additive manufacturing:novel metrics for safety evaluation and biomechanical performance

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Bio-Design and Manufacturing 2022年第2期5卷 333-347页

作者： Manuel Pinheiro Anouar Krairi Robin Willaert Maria C.Costa wim Van Paepegem Mechanics of Materials and Structures(MMS) Ghent UniversityGhentBelgium Materials Innovation Institute(M2i) DelftThe Netherlands Department of Oral and Maxillofacial Surgery University Hospitals Leuven LeuvenBelgium 4 Department of Head and Neck SurgeryGhent University HospitalGhentBelgium

Total temporomandibular joint(TMJ)replacement is recommended only when there is irreversible damage to the joint and no conservative treatment can provide functional *** stock and custom-made TMJ implants have been made available;however,retrospective and comparative studies were unable to find significant differences between the two types of *** introduction of additive manufacturing(AM)techniques in medical practice allows for a greater freedom of design and a higher degree of device *** combination of AM with structural optimisation may streamline development and provide the key for fabricating biomechanic ally enhanced TMJ *** this study,structural optimis ation techniques were applied to develop and numerically validate a patient-specific TMJ *** biomechanical behaviour of each intermediate TMJ design was assessed under four different nominal and maximum biting tasks using finite element *** addition,a new set of metrics were proposed to compare each design regarding biomechanical performance and implant *** results suggest that 55-82%of the natural/intact strain patterns can be recovered with the finally selected TMJ *** represents an increase of 15%in biomechanical performance for incisor biting,15%for right molar biting,17%for left molar biting and a decrease of 2%for left group biting compared with the initial *** results also suggest that load transfer at the proximal ramus reduces the implant’s impact on the mandible’s strain ***,structural optimisation allows for a volume reduction of up to 44%with a minimum loss of implant safety and biomechanical performance.

关键词： Temporomandibular joint Additive manufacturing Implant safety Biomechanical performance Finite element analysis

A Preconditioned Iterative Solver for the Scattering Solutions of the Schr¨odinger Equation

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Communications in Computational Physics 2012年第2期11卷 415-434页

作者： Hisham bin Zubair Bram Reps wim Vanroose Department of Mathematical Sciences Faculty of Computer ScienceInstitute of Business AdministrationUniversity Rd.75270 KarachiPakistan Department of Mathematics and Computer Science University of AntwerpMiddelheimlaan 1B-2020 AntwerpenBelgium

The Schrodinger equation defines the dynamics of quantum particles which has been an area of unabated interest in *** demonstrate how simple transformations of the Schrodinger equation leads to a coupled linear system,whereby each diagonal block is a high frequency Helmholtz *** on this model,we derive indefinite Helmholtz model problems with strongly varying *** employ the iterative approach for their *** particular,we develop a preconditioner that has its spectrum restricted to a quadrant(of the complex plane)thereby making it easily invertible by multigrid methods with standard *** multigrid preconditioner is used in conjunction with suitable Krylov-subspace methods for solving the indefinite Helmholtz model *** aim of this study is to report the feasibility of this preconditioner for the model *** compare this idea with the other prevalent preconditioning ideas,and discuss its *** of numerical experiments are presented,which complement the proposed ideas,and show that this preconditioner may be used in an automatic setting.

关键词： Scattering Schrodinger equation exterior complex scaling preconditioning multigrid complex-shifted Laplacian(CSL) complex-scaled grid(CSG) quadrant-definite(QD)