检索结果-南通市图书馆

Computer Modeling in Engineering & Sciences 2019年第4期119卷 35-62页

作者： andrew lundberg Pengtao Sun Cheng Wang Chen-song Zhang Department of Mathematical Sciences University of NevadaLas Vegas4505 Maryland ParkwayLas VegasNV 89154USA School of Mathematical Sciences Tongji UniversityShanghaiChina LSEC&NCMIS Academy of Mathematics and System ScienceBeijingChina

The distributed Lagrange multiplier/fictitious domain(DLM/FD)-mixed finite element method is developed and analyzed in this paper for a transient Stokes interface problem with jump *** semi-and fully discrete DLM/FD-mixed finite element scheme are developed for the first time for this problem with a moving interface,where the arbitrary Lagrangian-Eulerian(ALE)technique is employed to deal with the moving and immersed *** and optimal convergence properties are obtained for both *** experiments are carried out for different scenarios of jump coefficients,and all theoretical results are validated.

关键词： Transient Stokes interface problem jump coefficients distributed Lagrange multiplier fictitious domain method mixed finite element an optimal error estimate stability

Deformation,fragmentation and acceleration of a controlled fragmentation charge casing

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） 2019年第5期15卷 786-795页

作者： Andreas Helte Olof Andersson Patrik lundberg FOI Defence and SecuritySystems and Technology

Two different finite element software,LS-DYNA and Impetus,have been evaluated to test their ability to predict the deformation,fragmentation and acceleration of a controlled fragmentation charge *** general-purpose program LS-DYNA was used with a multi-material ALE formulation and a masspreserving erosion criterion coupled to a Johnson-Cook fracture *** the Impetus simulations,a third order Lagrangian element formulation was used for the casing and a node-splitting element erosion treatment coupled to a Cockcroft-Latham failure criterion was used to describe casing *** high-explosive gases were described by a discrete particle *** order to acquire data to validate our computational tools and constitutive models,a series of experiments have been performed using a laboratory charge with an internal grooved *** the test series,the charge geometry was fixed except that the groove depth were varied from very shallow to very deep resulting in different deformation patterns,fracture modes and terminal *** diagnostic tools captured the different stages of the expansion and fragmentation of the casing.A high-speed framing camera depicted the deformation pattern before fragmentation and was used to determine the moment when the casing *** different complementary techniques were used to follow the acceleration of the fragments;a Photon Doppler velocimetry to determine the initial acceleration of the casing,double exposed radiographs to estimate the fragment velocity after break-up and a high-speed video to determine the terminal velocity of the fragment after leaving the *** addition,the fragments were soft recovered in a set of sawdust pit tests and their final shape and weight were measured.A SEM was used to characterise the fracture surfaces and to determine the modus of fracture(tensile or shear failure).Comparisons to experiments show that both software can predict the change in deformation behaviour

关键词： Controlled fragmentation Fracture mechanics LS-DYNA Impetus

Improving Fault Detection in Modified Code-A Study from the Telecommunication Industry

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2007年第3期22卷 397-409页

作者： Piotr Tomaszewski Lars lundberg Hkan Grahn School of Engineering Blekinge Institute of Technology SE-372 25 RonnebySweden

Many software systems are developed in a number of consecutive releases. In each release not only new code is added but also existing code is often modified. In this study we show that the modified code can be an important source of faults. Faults are widely recognized as one of the major cost drivers in software projects. Therefore, we look for methods that improve the fault detection in the modified code. We propose and evaluate a number of prediction models that increase the efficiency of fault detection. To build and evaluate our models we use data collected from two large telecommunication systems produced by Ericsson. We evaluate the performance of our models by applying them both to a different release of the system than the one they are built on and to a different system. The performance of our models is compared to the performance of the theoretical best model, a simple model based on size, as well as to analyzing the code in a random order （not using any model）. We find that the use of our models provides a significant improvement over not using any model at all and over using a simple model based on the class size. The gain offered by our models corresponds to 38-57% of the theoretical maximum gain.

关键词： fault prediction metrics testing and debugging

Influence of confining prestress on the transition from interface defeat topenetration in ceramic targets

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2016年第3期12卷 263-271页

作者： Patrik lundberg RenéRENSTROM Olof ANDERSSON FOI Swedish Defence Research AgencySE-164 90 StockholmSweden

Replica scaled impact experiments with unconfined ceramic targets have shown that the transition velocity,i.e.,the impact velocity at which interface defeat ceases and ceramic penetration occurs,decreased as the length scale increased.A possible explanation of how this scale effect is related to the formation of a cone crack in the ceramic has been presented by the authors in an earlier ***,the influence of confinement and prestress on cone cracking and transition velocity is *** hypothesis is that prestress will suppress the formation and growth of the cone crack by lowering the driving stress.A set of impact experiments has been performed in which the transition velocity for four different levels of prestress has been *** transition velocities as a function of the level of confining prestress is compared to an analytical model for the influence of prestress on the formation and extension of the cone crack in the ceramic *** experiments and model indicate that prestress has a strong influence on the transition from interface defeat to penetration,although the model underestimates the influence of prestress.

关键词： Impact Ceramic Armour Interface defeat Dwell Confinement Prestress

Gene-environment interactions in male reproductive health： special reference to the aryl hydrocarbon receptor signaling pathway

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2014年第1期16卷 89-96页

作者： Leon J S Brokken Yvonne lundberg Giwercman Department of Clinical Sciences Molecular Genetic Reproductive Medicine Lund University MalmO Sweden

Over the last few decades, there have been numerous reports of adverse effects on the reproductive health of wildlife and laboratory animals caused by exposure to endocrine disrupting chemicals （EDCs）. The increasing trends in human male reproductive disorders and the mounting evidence for causative environmental factors have therefore sparked growing interest in the health threat posed to humans by EDCs, which are substances in our food, environment and consumer items that interfere with hormone action, biosynthesis or metabolism, resulting in disrupted tissue homeostasis or reproductive function. The mechanisms of EDCs involve a wide array of actions and pathways. Examples include the estrogenic, androgenic, thyroid and retinoid pathways, in which the EDCs may act directly as agonists or antagonists, or indirectly via other nuclear receptors. Dioxins and dioxin-like EDCs exert their biological and toxicological actions through activation of the aryl hydrocarbon-receptor, which besides inducing transcription of detoxifying enzymes also regulates transcriptional activity of other nuclear receptors. There is increasing evidence that genetic predispositions may modify the susceptibility to adverse effects of toxic chemicals. In this review, potential consequences of hereditary predisposition and EDCs are discussed, with a special focus on the currently available publications on interactions between dioxin and androgen signaling.

关键词： androgen receptor aryl hydrocarbon receptor endocrine disrupter

Running Temperature and Mechanical Stability of Grease as Maintenance Parameters of Railway Bearings

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 Automation and computing 2010年第2期7卷 160-166页

作者： Jan lundberg Aditya Parida Peter Sderholm Division of Operation and Maintenance Engineering Lule University of Technology

Spherical roller bearings in railway car wheels are critical components whose failure may have catastrophic consequences. The present study aims to analyse the mechanical stability of greases and temperature of bearings as indicators for condition-based bearing maintenance. The performed case study includes nine fully-formulated commercial greases examined in the wheel bearings of five ore cars operated in northern Scandinavia. The studied ore cars travelled a distance of about 300 000 km during a period of three years. Small samples of the greases were taken on eight occasions to test their mechanical stability. In addition, the temperatures of the bearings were continuously recorded. After the test period, the wear, electrical damage, and corrosion of the bearings were examined. One of the findings is that the shear stress of the grease at a certain shear velocity （the certain yieldstress （CEY） value） is a good maintenance indicator and is highly dependent on the grease type. The bearing＇s wear, electrical damage and corrosion also depend on the grease type. However, no oxidation of the greases was identified. The paper also outlines a systematic methodology to determine an overall maintenance indicator for railway roller bearings which is based on the field measurements.

关键词： Maintenance mechanical stability railway roller bearings grease lubrication.

Ultra-wide field imaging in the screening of diabetic retinopathy

在线全文

学校读者我要写书评

暂无评论

Annals of Eye Science 2019年第1期4卷 1-3页

作者： Jakob Grauslund Malin lundberg Rasmussen Department of Ophthalmology Odense University HospitalOdenseDenmark Department of Clinical Research Faculty of Health ScienceUniversity of Southern DenmarkOdenseDenmark Steno Diabetes Center Odense Odense University Hospital and Svendborg HospitalOdenseDenmark

Despite recent advancements in care,diabetic retinopathy(DR)remains an important cause of blindness(1,2).Screening of DR has been introduced as part of the health care systems in various countries(3-5),and,consequently,recent data from UK have demonstrated that DR is no longer the leading cause of blindness in the working-age population(6).

关键词： diabetic retinopathy spite

On the sampling strategies and models for measuring diffusion exchange with a double diffusion encoding sequence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Magnetic Resonance Letters 2023年第3期3卷 232-247,I0003页

作者： Alfredo Ordinola Shan Cai Peter lundberg Ruiliang Bai Evren Ozarslan Department of Biomedical Engineering(IMT) Link oping UniversityLink opingS-58185Sweden Department of Radiation Physics Department of HealthMedicine and Caring Sciences(HMV)Link oping UniversityLink opingS-58183Sweden Center for Medical Image Science and Visualization(CMIV) Link oping UniversityLink opingS-58185Sweden School of Medicine Zhejiang University866 Yuhangtang RdHangzhou310058China

Water exchange between the different compartments of a heterogeneous specimen can be characterized via diffusion magnetic resonance imaging(dMRI).Many analysis frameworks using dMRI data have been proposed to describe exchange,often using a double diffusion encoding(DDE)stimulated echo *** such as diffusion exchange weighted imaging(DEWI)and the filter exchange and rapid exchange models,use a specific subset of the full space DDE *** this work,a general representation of the DDE signal was employed with different sampling schemes(namely constant b1,diagonal and anti-diagonal)from the data reduction models to estimate exchange.A near-uniform sampling scheme was proposed and compared with the other sampling *** filter exchange and rapid exchange models were also applied to estimate exchange with their own subsampling *** subsampling schemes and models were compared on both simulated data and experimental data acquired with a benchtop MR *** synthetic data,the diagonal and near-uniform sampling schemes performed the best due to the consistency of their estimates with the ground *** experimental data,the shifted diagonal and near-uniform sampling schemes outperformed the others,yielding the most consistent estimates with the full space *** results suggest the feasibility of measuring exchange using a general representation of the DDE signal along with variable sampling *** future studies,algorithms could be further developed for the optimization of sampling schemes,as well as incorporating additional properties,such as geometry and diffusion anisotropy,into exchange frameworks.

关键词： Diffusion MRI Water exchange Sampling schemes Double diffusion encoding

Androgen receptor gene CAG and GGN repeat lengths as predictors of recovery of spermatogenesis following testicular germ cell cancer treatment

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2017年第5期19卷 538-542页

作者： Karolina Bogefors Yvonne lundberg Giwercman Jakob Eberhard Olof Stahl Eva Cavallin-Stahl Gabriella Cohn-Cedermark Stefan Arver Aleksander Giwercman Reproductive Medicine Centre Skane University Hospital Malmo Sweden Department of Oncology Skane University Hospital Malmo Sweden Department of Translational Medicine Lund University Malmo Sweden Department of Oncology Skane University Hospital Lund Sweden Radiumhemmet Karolinska HospitalStockholm Sweden Centre of Andrology and Sexual Medicine Karolinska Hospital Stockholm Sweden

Spermatogenesis is an androgen-regulated process that depends on the action of androgen receptor （AR）. Sperm production may be affected in men treated for testicular cancer （TC）, and it is important to identify the factors influencing the timing of spermatogenesis recovery following cancer treatment. It is known that the CAG and GGN repeat numbers affect the activity of the AR; therefore, the aim of this study is to investigate if the CAG and GGN polymorphisms in the AR gene predict recovery of sperm production after TC treatment. TC patients （n = 130） delivered ejaculates at the following time points： postorchiectomy and at 6, 12, 24, 36, and 60 months posttherapy （TO, T6, T12, T24, T36, and T60）. The CAG lengths were categorized into three groups, 〈22 CAG, 22-23 CAG, and 〉23 CAG, and the GGN tracts were also categorized into three groups, 〈23 GGN, 23 GGN, and 〉23 GGN. At T12, men with 22-23 CAG presented with a statistically significantly （P = 0.045） lower sperm concentration than those with other CAG numbers （8.4 × 10^6 ml^-1 vs 16 × 10^6 ml^-1; 95% CI： 1.01-2.65）. This association was robust to omitting adjustment for treatment type and sperm concentration at TO （P= 0.021; 3.7× 10^6 ml^-1 vs 10 × 10^6 ml^-1; 95% CI： 1.13-4.90）. The same trends were observed for total sperm number. The least active AR variant seems to be associated with a more rapid recovery of spermatogenesis. This finding adds to our understanding of the biology of postcancer therapy recovery of fertility in males and has clinical implications.

关键词： androgen receptor CAG and GGN repeat sperm number testicular cancer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

SGP、BCTMP的应用

中华纸业 2004年第2期25卷 31-32页

作者： PAGNAR lundberg ROTTNEROS AB

SGP是磨石磨木浆,是通过磨石磨木直接获得的机械浆,由于强度低、白度低,以往主要用于新闻纸的生产.BCTMP是漂白化学热磨机械浆,具有低密度、高韧性、成纸不透明度高等特点.近年来BCTMP用途在逐渐扩大,甚至用于高档纸种.本文简要综述SGP... 详细信息

SGP是磨石磨木浆,是通过磨石磨木直接获得的机械浆,由于强度低、白度低,以往主要用于新闻纸的生产.BCTMP是漂白化学热磨机械浆,具有低密度、高韧性、成纸不透明度高等特点.近年来BCTMP用途在逐渐扩大,甚至用于高档纸种.本文简要综述SGP、BCTMP用于抄造纸板、文化用纸、薄型纸等品种的实例.

关键词： SGP 磨石磨木浆 BCTMP 漂白化学热磨机械浆抄造纸板文化用纸薄型纸纸浆