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Modelling and simulation of fixtures during grinding

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Science China(Technological Sciences) 2009年第7期52卷 1821-1829页

作者： matthias KLAERNER Juergen LEOPOLD Lothar KROLL Institute of Mechanical and Polymer Engineering Chemnitz University of Technology09107 ChemnitzGermany Fraunhofer Institute for Machine Tools and Forming Technology 09126 ChemnitzGermany

The complex workpiece-fixture behaviour during machining is an essential component of the fixture development *** detail,the forces acting on fixture components have to be analysed.A method for the prediction of the reaction forces due to process and clamping loads is presented in this *** the beginning,detailed information about the workpiece-fixture behaviour during the process is determined by a complex finite element ***,the reduction of the number of elements leads to a smaller model with less computation time,validated and used for the variation of process ***,an analytical description is developed based on the combination of both *** the help of the empiric equation it is possible to predict the reaction forces and the dependency on several process *** method has been validated by modelling shape grinding of a nozzle guide vane.

关键词： clamping forces grinding finite element method fixture

Longitudinal height-diameter curves for Norway spruce, Scots pine and silver birch in Norway based on shape constraint additive regression models

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Forest Ecosystems 2018年第2期5卷 109-125页

作者： matthias Schmidt Johannes Breidenbach Rasmus Astrup Northwest German Forest Research Institute Forest Growth Gratzelstr 2 37079 Gottingen Germany Norwegian Institute for Bioeconomy Research National Forest Inventory Postboks 115 1431 As Norway

Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter

关键词： Height-diameter curve Norway spruce Scots pine Silver birch Norwegian national forest inventory Shape constrained additive models

Modelling the population fluctuation of winter moth and mottled umber moth in central and northern Germany

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Forest Ecosystems 2019年第1期6卷 38-55页

作者： Anika Hittenbeck Ronald Bialozyt matthias Schmidt Northwest German Forest Research Institute

Background: Winter moth(Operophtera brumata) and mottled umber moth(Erannis defoliaria) are forest Lepidoptera species characterized by periodic high abundance in a 7–11 year cycle. During outbreak years they cause severe defoliation in many forest stands in Europe. In order to better understand the spatio-temporal dynamics and elucidate possible influences of weather, stand and site conditions, a generalized additive mixed model was developed. The investigated data base was derived from glue band catch monitoring stands of both species in Central and North Germany. From the glue bands only female moth individuals are counted and a hazard code is calculated. The model can be employed to predict the exceedance of a warning threshold of this hazard code which indicates a potential severe defoliation of oak stands by winter moth and mottled umber in the coming ***: The developed model accounts for specific temporal structured effects for three large ecoregions and random effects at stand level. During variable selection the negative model effect of pest control and the positive model effects of mean daily minimum temperature in adult stage and precipitation in early pupal stage were ***: The developed model can be used for short-term predictions of potential defoliation risk in Central and North Germany. These predictions are sensitive to weather conditions and the population dynamics. However, a future extension of the data base comprising further outbreak years would allow for deeper investigation of the temporal and regional patterns of the cyclic dynamics and their causal influences on abundance of winter moth and mottled umber.

关键词： Operophtera brumata Erannis defoliaria Generalized additive mixed model Weather effect Insect pest outbreaks

Do viral infections protect from or enhance type 1 diabetes and how can we tell the difference?

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Cellular & Molecular Immunology 2011年第3期8卷 193-198页

作者： Urs Christen matthias G von Herrath Pharmazentrum Frankfurt/ZAFES Klinikum der Goethe UniversitaätFrankfurt am MainGermany La Jolla Institute for Allergy and Immunology La JollaCAUSA

Virus infections have been implicated in both initiation of and protection from autoimmune diseases,such as type 1 diabetes(T1D).In this review we intend to reflect on recent evidence how viruses might on the one hand be involved in the pathogenesis of T1D and on the other hand induce a state of protection from autoimmune-mediated *** is important to acknowledge that human individuals encounter more than just one virus infection in their ***,it is important to integrate more than just one possible environmental triggering factor for autoimmune diseases to occur.

关键词： animal model enterovirus hygiene hypothesis molecular mimicry pathogens

Resistance switching in oxides with inhomogeneous conductivity

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Chinese Physics B 2013年第6期22卷 1-18页

作者：尚大山孙继荣沈保根 Wuttig matthias Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences I.Physikalisches Institut(IA) RWTH Aachen University

Electric-field-induced resistance switching （RS） phenomena have been studied for over 60 years in metal/dielectrics/metal structures. In these experiments a wide range of dielectrics have been studied including binary transition metal oxides, perovskite oxides, chalcogenides, carbon- and silicon-based materials, as well as organic materials. RS phenomena can be used to store information and offer an attractive performance, which encompasses fast switching speeds, high scalability, and the desirable compatibility with Si-based complementary metal-oxide-semiconductor fabrication. This is promising for nonvolatile memory technology, i.e., resistance random access memory （RRAM）. However, a comprehensive understanding of the underlying mechanism is still lacking. This impedes faster product development as well as accurate assessment of the device performance potential. Generally speaking, RS occurs not in the entire dielectric but only in a small, confined region, which results from the local variation of conductivity in dielectrics. In this review, we focus on the RS in oxides with such an inhomogeneous conductivity. According to the origin of the conductivity inhomogeneity, the RS phenomena and their working mechanism are reviewed by dividing them into two aspects： interface RS, based on the change of contact resistance at metal/oxide interface due to the change of Schottky barrier and interface chemical layer, and bulk RS, realized by the formation, connection, and disconnection of conductive channels in the oxides. Finally the current challenges of RS investigation and the potential improvement of the RS performance for the nonvolatile memories are discussed.

关键词： resistance switching inhomogeneous conductivity transition metal oxide

Smoking prevalence in the area of responsibility of the German Ministry of Defense——results of the employee survey in the context of occupational health management

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Military Medical Research 2020年第3期7卷 343-349页

作者： Stefan Sammito Annika Claus Dirk-matthias Rose Department I 3 Research&Development Air Force Centre of Aerospace MedicineCologneGermany Occupational Medicine Faculty of MedicineOtto-von-Guericke-University of MagdeburgMagdeburgGermany Institute for Teachers’Health Institute of OccupationalSocial and Environmental Medicine of the Johannes-Gutenberg University MainzMainzGermany

Background:Tobacco use,correlated with reduced physical fitness,is one of the leading causes of avoidable death *** increases the risk of dementia and can shorten the lifespan by 10 *** the German Armed Forces(Bundeswehr),figures on smoking behavior have not been comprehensively *** study analyzes current data in a large sample from this ***:Based on an employee survey as part of the Occupational Health Management System,data on smoking behavior from 13,326 participants were analyzed in relation to age,gender,professional status,education level and membership in military operational units versus other ***:Smoking behavior varied significantly(Polder),gender,professional status,military agency membership status,and education level(the lower the education level,the higher the smoking rates).With the exception of the downward trend in smoking behavior with increasing age among civilian employees,these results were all significant(P<0.005).Conclusions:This data analysis shows that smoking prevalence among personnel in the area of responsibility of the Federal Ministry of Defense is comparable to the current data from corresponding surveys of the German *** on gender,they generally show values that are slightly above those of the German *** well-known trend in the general population of decreasing smoking prevalence with increasing age is also seen in this ***,there are considerable differences in the smoking prevalence among individual subgroups(professional status,agency,gender,education level).The data show that particular young soldiers in the armed forces should be the target group for further preventive measures.

关键词： Prevention Smoking Military Health promotion

Screening of the whole human cytochrome P450 complement(CYPome)with enzyme bag cocktails

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Journal of Pharmaceutical Analysis 2020年第3期10卷 271-276页

作者： Sangeeta Shrestha Sharma Shishir Sharma matthias Bureik School of Pharmaceutical Science and Technology Health Sciences PlatformTianjin UniversityTianjin300072China

We have previously introduced the use of permeabilized fission yeast cells(enzyme bags)that recombinantly express full-length CYPs for drug metabolism *** enzyme bags are cells with pores that function as enzymes in *** can easily be prepared without a need for ultracentrifugation and may be used in similar protocols as *** this study we report the preparation of enzyme bag cocktails that permit the testing of multiple CYPs in a single enzyme bag ***,we established a convenient testing scheme that permits a rapid screen of all human CYPs for activity towards any given candidate *** important aspect of this approach is the reduction of individual CYP test *** a cocktail containing many CYPs tests negative,it follows that all CYPs included in that cocktail need not be tested individually,thus saving time and *** new protocol was validated using two probe substrates.

关键词： Cytochrome P450 Drug metabolism Fission yeast Luminescence Proluciferin

Tire abrasion particles negatively affect plant growth even at low concentrations and alter soil biogeochemical cycling

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Soil Ecology Letters 2022年第4期4卷 409-415页

作者： Eva F.Leifheit Hanna L.Kissener Erik Faltin Masahiro Ryo matthias C.Rillig Freie Universitat Berlin Institut fur Biologie14195 BerlinGermany Berlin-Brandenburg Institute of Advanced Biodiversity Research 14195 BerlinGermany Leibniz Centre for Agricultural Landscape Research(ZALF) 15374 MünchebergGermany Brandenburg University of Technology Cottbus-Senftenberg 03046 CottbusGermany

Tire particles(TPs)are a major source of microplastic on land,and considering their chemical composition,they represent a potential hazard for the terrestrial *** studied the effectsof TPs at environmentally relevant concentrations alongawide concentrationgradient(0–160 mg g^(-1))and tested the effects on plant growth,soil pH and the key ecosystem process of litter decomposition and soil *** addition of TPs negatively affected shoot and root growth already at low *** litter decomposition slightly increased with lower additions of TPs but decreased later *** pH increased until a TP concentration of 80 mg g^(-1) and leveled off *** respiration clearly increased with increasing concentration of added *** growth was likely reduced with starting contamination and stopped when contamination reached a certain level in the *** presence of TPs altered a number of biogeochemical soil parameters that can have further effects on plant *** the quantities of yearly produced TPs,their persistence,and toxic potential,we assume that these particles will eventually have a significant impact on terrestrial ecosystems.

关键词： Microplastic pollution Tire particles Plant growth Soil respiration Soil pH Litter decomposition

VEGF in the nervous system: an important target for research in neurodevelopmental and regenerative medicine

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Neural Regeneration Research 2015年第11期10卷 1725-1726页

作者： matthias Dumpich Carsten Theiss Faculty of Medicine Institute of Anatomy Department of Cytology Ruhr-University Bochum

Vascular endothelial growth factor（VEGF）in neurodevelopment and regeneration：VEGF is a well-known factor that promotes vascularization and *** this it participates in the pathogenesis of several diseases,such as colorectal carcinoma,lung cancer or diabetic *** the last decade,VEGF has been successfully integrated into the treatment of such diseases,for example as a therapy for colorectal cancer with the VEGF-receptor （VEGFR）-inhibitor axitinib.

关键词： VEGF in the nervous system an important target for research in neurodevelopmental and regenerative medicine