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An approach of the internal friction-dependent temperature changes for conventional and pure biogenic lubricating greases

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friction 2024年第4期12卷 780-795页

作者： Leif AHME Erik kuhn MiguelÁngel DELGADO Department of Mechanical Engineering and production Management Hamburg University of Applied SciencesHamburg 20099Germany Department of Chemical Engineering Research in Product Technology and Chemical Processes(Pro2TecS)University of HuelvaHuelva 21071Spain

This work investigated the temperature changes inside the bulk of lubricating greases under controlled high-shear stress conditions(250-500 s-1).for this purpose,a newly developed temperature-measuring cell called Calidus was successfully *** temperature changes(ΔT)have been related to the greases'components(thickener,base oil-type,and composition)and the structural degradation of the lubricating ***,a theoretical approach was proposed for calculating the internal temperature change of lubricating greases during shear *** greases showed an internal temperature profile characterised by a sudden rise inΔT within the first 4 h from starting the test and subsequentΔT decay until it reaches the steady state ***,it was found that greases C1 and C5,formulated with lithium and calcium soap,respectively,with different soap content(16.1 wt%and 9.7 wt%,respectively),but the same base castor oil,showed the highest value of the maximumΔT,c.a.3.2 K,and the most drastic drop ofΔ*** greases showed both the highest specific densities and heat *** addition,they showed the lowest ratio of expended energies(Rtee),which means more structural degradation in the stressed *** the contrary,the grease C3,with 13 wt%of Li-soap but the lowest base oil's viscosity,showed the lowest maximumΔT and the temperature profile was characterised by a moderate variation ofΔT along the *** biogenic grease B3 developed a low-temperature change in the group of pure bio-genic greases close to grease C3.

关键词： shear-induced structural degradation rheology temperature measurements lubricating greases density lubricating greases specific heat capacities

全身非增强pET/MR与pET/CT在肿瘤分期与再分期的初步观察

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国际医学放射学杂志 2015年第1期 78-79页

作者： M.W.Huellner p.Appenzeller f.p.kuhn L.Husmann C.M.pietsch I.A.Burger Department of Medical Radiology Divisions of Nuclear MedicineUniversity Hospital Zurich

目的评价全身非增强pET/MR和pET/CT对肿瘤分期和再分期的诊断效能及对扫描的模式和序列的选择提供指导。材料与方法机构审查委员会和国家政府部门批准

关键词：再分期肿瘤分期 pET/MR MR CT 全身

The dual role of striatal interneurons:circuit modulation and trophic support for the basal ganglia

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Neural Regeneration Research 2024年第6期19卷 1277-1283页

作者： Elliot Wegman Marlena Wosiski-kuhn Yu Luo Department of Molecular and Cellular Biosciences University of CincinnatiCincinnatiOHUSA Department of Emergency Medicine at the School of Medicine University of CincinnatiCincinnatiOHUSA Neuroscience Graduate program University of CincinnatiCincinnatiOHUSA

Striatal interneurons play a key role in modulating striatal-dependent behaviors,including motor activity and reward and emotional *** not only provide modulation to the basal ganglia circuitry under homeostasis but are also involved in changes to plasticity and adaptation during disease conditions such as parkinson's or Huntington's *** review aims to summarize recent findings regarding the role of striatal cholinergic and GABAergic interneurons in providing circuit modulation to the basal ganglia in both homeostatic and disease *** addition to direct circuit modulation,striatal interneurons have also been shown to provide trophic support to maintain neuron populations in *** discuss this interesting and novel role of striatal interneurons,with a focus on the maintenance of adult dopaminergic neurons from interneuronderived sonic-hedgehog.

关键词： cholinergic dopamine GABAergic interneuron levodopa-induced dyskinesia parvalbumin sonic hedgehog striatum trophic factor

Variability in nanoscale CMOS technology

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Science China(Information Sciences) 2011年第5期54卷 936-945页

作者： kuhn Kelin portland Technology Development Intel Corporation Hillsboro OR 97124 USA

Moore’s Law technology scaling has improved VLSI performance by five orders of magnitude in the last four decades. As advanced technologies continue the pursuit of Moore’s Law, a variety of challenges will need to be overcome. One of these challenges is management of process variation. This paper discusses the importance of process variation in modern CMOS transistor technology, reviews front-end variation sources, presents device and circuit variation measurement techniques (including circuit and SRAM data from the 32 nm node), and compares recent intrinsic transistor variation performance from the literature.

关键词： CMOS variation SRAM Vccmin

Rapid manufacture of Ni-based superalloy components by three-dimensional printing

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中国有色金属学会会刊：英文版 2006年第A3期16卷 1901-1905页

作者：刘建新 H.A.kuhn proMetal Division The Ex One Company8075 Pennsylvania AvenueIrwinPA 15642USA

The challenge to rapid manufacturing high performance metal components is how to consolidate the uncompressed powder preforms to full or near full density without shape distortion. A new approach developed by proMetal was proposed, in which a bimodal powder, typically a coarse prealloyed powder blended with a fine metal powder was used to build green preforms by three-dimensional printing and then sintered at a temperature above the solidus temperature of the coarse prealloyed powder and below the melting temperature of the fine powder particles or the solidus temperature if the fine powder is a prealloyed powder as well. This approach was successfully applied to sinter Ni-based superalloy 718 preforms, which were built through three dimensional printing into near full density.

关键词：高温合金镍三维结构金相

Sediment generation and soil mound denudation in areas of high-density tree throw along a river valley in the Jura Mountains, Switzerland

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Journal of Mountain Science 2021年第2期18卷 377-391页

作者： philip GREENWOOD Jan BAUER Nikolaus J kuhn physical Geography&Environmental Change Research Group Department of Environmental SciencesUniversity of BaselKlingelbergstrasse 27Basel-4056Switzerland

A preliminary field-based investigation was undertaken in a small(<10 km^(2))river valley located in the mountainous Jura region of northwest *** aims of the work were to assess sediment generation and annual sediment... 详细信息

A preliminary field-based investigation was undertaken in a small(f northwest *** aims of the work were to assess sediment generation and annual sediment transport rates by tree throw on forested hillslopes,and to document surface hydrology characteristics on four fresh soil mounds associated with recent tree throws over a 24-day monitoring *** the soil mounds,average sediment recovery ranged from 7.7-28.2 g(dry weight),equivalent to a suspended sediment concentration of 145.2-327.8 g L^(-1),and runoff coefficients ranged from 1.0%-4.2%.Based on a soil bulk density value of 1,044 kg m^(-3),upslope runoff generation areas were denuded by an average 0.14 mm by the end of the 24-day monitoring period,representing an erosion rate equivalent to 2.1 mm yr^(-1).A ca.50 cm high soil mound could therefore feasibly persist for around 200-250 *** tree throw work,the dimensions of 215 individual tree throws were measured and their locations mapped in 12 separate locations along the river valley representing a cumulative area equivalent to 5.3 ha(***,43 per ha).Tree throws generated a total of 20.1 m^(3) of fine-sediment(f 3.8×10^(-4) m^(3) m^(-2).The process of tree throw was originally attributed to two extreme weather events that occurred in west and central Europe in late December *** the 18-year period since both storms,this represents an annual sediment transport rate of 2.7×10^(-5) m^(3) m^(-1) yr^(-1).Exploring the relationship with wind on fall direction,65.5%of tree throws(143)generally fell in a downslope direction irrespective of hillslope aspect on which they were *** infers that individual storms may not have been responsible for the majority of tree throws,but instead,could be associated with root *** the high density of tree throws and their relative maturity(average age 41 years),we hypothesise that once tr

关键词： Tree throw Hillslope processes Sediment generation mechanism Sediment transport rate Soil mound Ibach river valley

Multi-scale drivers of soil resistance predict vulnerability of seasonally wet meadows to trampling by pack stock animals in the Sierra Nevada,USA

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Ecological processes 2020年第1期9卷 364-377页

作者： Joy S.Baccei Mitchel p.McClaran Tim J.kuhn Stephen C.Hart Environmental Systems Graduate Group University of CaliforniaMercedCA 95343USA UC Merced Vernal pools and Grassland Reserve UC Merced Natural Reserve SystemMercedCA 95343USA School of Natural Resources and the Environment University of ArizonaTucsonAZ 85721USA Resources Management and Science Yosemite National ParkEl PortalCA 95318USA Department of Life&Environmental Sciences and Sierra Nevada Research Institute University of CaliforniaMercedCA 95343USA.

Background:Meadow ecosystems have important ecological functions and support socioeconomic services,yet are subject to multiple stressors that can lead to rapid *** the Sierra Nevada of the western USA,recreational pack stock(horses and mules)use in seasonally wet mountain meadows may lead to soil trampling and meadow degradation,especially when soil water content is high and vegetation is ***:In order to improve the ability to predict meadow vulnerability to soil disturbance from pack stock use,we measured soil resistance(SR),which is an index of vulnerability to trampling disturbance,at two spatial scales using a stratified-random sampling *** then compared SR to several soil and vegetation explanatory variables that were also measured at the two spatial scales:plant community type(local scale)and topographic gradient class(meadow scale).Results:We found that local-scale differences in drivers of SR were contingent on the meadow scale,which is important because multiple spatial scale evaluation of ecological metrics provides a broader understanding of the potential controls on ecological processes than assessments conducted at a single spatial *** also found two contrasting explanatory models for drivers of SR at the local scale:(1)soil gravimetric water content effects on soil disaggregation and(2)soil bulk density and root mass influence on soil *** resistance was insufficient to sustain pack stock use without incurring soil deformation in wet plant communities,even when plant cover was maximal during a major ***:Our study provides new information on seasonally wet meadow vulnerability to trampling by pack stock animals using multi-scale drivers of SR,including the contrasting roles of soil disaggregation,friction,and *** work aims to inform meadow management efforts in the Sierra Nevada and herbaceous ecosystems in similar regions that are subject to seasonal soil saturation and livestock u

关键词： Hydrogeomorphic classification Hydrologic regime pack stock plant communities Soil properties Soil strength

Improving risk reduction potential of weather index insurance by spatially downscaling gridded climate data-a machine learning approach

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Big Earth Data 2023年第4期7卷 937-960页

作者： Sarvarbek Eltazarov Ihtiyor Bobojonov Lena kuhn Thomas Glauben Department of Agricultural Markets Marketing and World Agricultural TradeLeibniz Institute of Agricultural Development in Transition Economies(IAMO)HalleGermany

Open-access gridded climate products have been suggested as a potential source of data for index insurance design and operation in data-limited ***,index insurance requires climate data with long historical records,global geographical coverage and fine spatial resolution at the same time,which is nearly impossible to satisfy,especially with open-access *** this paper,we spatially downscaled gridded climate data(precipitation,temperature,and soil moisture)in coarse spatial resolution with globally available longterm historical records to finer spatial resolution,using satellite-based data and machine learning *** then investigated the effect of index insurance contracts based on downscaled climate data for hedging spring wheat *** study employed countylevel spring wheat yield data between 1982 and 2018 from 56 counties overall in Kazakhstan and *** results showed that in the majority of cases(70%),hedging effectiveness of index insurances increases when climate data is spatially downscaled with a machine learning *** improvements are statistically significant(p≤0.05).Among other climate data,more improvements in hedging effectiveness were observed when the insurance design was based on downscaled temperature and precipitation ***,this study highlights the reasonability and benefits of downscaling climate data for insurance design and operation.

关键词： Climate risk management risk reduction extreme weather random forest ESA parametric insurance

performance evaluation of high/ultra-high-degree global geopotential models over Vietnam using GNSS/leveling data

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Geodesy and Geodynamics 2023年第5期14卷 500-512页

作者： Hoa Thi pham Sten Claessens Michael kuhn Joseph Awange School of Earth and planetary Sciences Spatial Sciences DisciplineCurtin UniversityPerthAustralia faculty of Surveying Mapping and Geographic InformationHanoi University of Natural Resources and EnvironmentHanoiViet Nam

The availability of many high-degree Global Geopotential Models(GGMs), namely EGM2008, EIGEN-6C4,GECO, SGG-UGM-1, SGG-UGM-2, XGM2019e_2159, and GGMplus, challenges users regarding which model is best for Vietnam. This study, therefore, evaluates their performance by comparing them with GNSS/leveling data over Vietnam. Results show that their absolute and relative performances are largely independent of topographic conditions and geographical location and can be ranked into three classes:(1)XGM2019e_2159 has the highest accuracy,(2) the models EIGEN-6C4, GECO, SGG-UGM-1, SGG-UGM-2, and GGMplus, have a very similar level of medium accuracy, while(3) EGM2008 is found to be the least accurate. In an absolute sense, the differences between GNSS/leveling and EGM2008-based height anomalies have a standard deviation(STD) of 0.290 ± 0.010 m, whereas, for XGM2019e_2159, this is 0.156 ± 0.006 *** other models have STDs of(0.18-0.19) ± 0.007 m. Regarding relative performance without fitting, all GGMs have comparable accuracies for baseline length of 5-20 km, while for baselines longer than 20 km,the STD of XGM2019e_2159 is 1.5 ppm-0.5 ppm(approximately 19%-40%) lower compared with EGM2008, and 0.5 ppm-0.25 ppm(approximately 7%-36%) lower compared with EIGEN6C4, GECO,SGG-UGM-1, SGG-UGM-2, and GGMplus. In addition, the STDs decrease significantly from 20 to 12 ppm in the range of 5-10 km, slightly from 12 to 6 ppm for 10-35 km, very slightly from 6 to 2.5 ppm for35-200 km, and then remain almost unchanged for longer baselines. After fitting, the relative accuracies of all GGMs are at the same level with negligible STD/RMSE values. furthermore, only EGM2008 experiences significant regional differences, while other GGMs show more homogeneous spatial variation of absolute accuracy over Vietnam. These findings can contribute to the development of local quasigeoid models in Vietnam and may be helpful with the improvement of GGMs in the future.

关键词： GGM Evaluation GNSS/Leveling EGM2008 EIGEN-6C4 GECO SGG-UGM-1 SGG-UGM-2 XGM2019e_2159 GGMplus