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DEM parameter calibration of cohesive bulk materials using a simple angle of repose test

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Particuology 2019年第4期17卷 105-115页

作者： thomas Roessler Andre Katterfeld Chair of Material Handling Institute of Logistics and Material Handling Systems University of Magdeburg Universitatsplatz 239106 Magdeburg Germany

The numerical effort of discrete element method (DEM) simulations results in a general idealisation of DEM models that makes the calibration crucial to obtaining realistic simulation results. The angle of repose test has become a standard test for the calibration of DEM parameters of cohesionless bulk materials and is extensively discussed in the literature. One of the most used test methods is the pull-up test of a hollow cylinder filled with bulk material. This paper presents how this basic pull-up test can also be used for the calibration of DEM parameters of cohesive materials by changing the analysis criteria. In contrast to analysing the static angle of repose, the focus lies on the macroscopic flow behaviour during the lifting of the cylinder. Reproducible phases of flow are identified in experiments: the build-up of a stable bulk material column, the convex bending of the column, and the beginning of collapse of the column. Furthermore, the phases are independent of the size and lifting velocity. The convex bending of the bulk-material column combined with the moment of first collapse are introduced as new measurable calibration criteria. These experimental results of wet sand are used for the calibration of related DEM parameters using a simplified JKR cohesion model. The DEM calibration including an analysis algorithm that fits the experimental flow behaviour and the final selection of the relevant parameters (i.e., sliding friction coefficient, rolling friction coefficient, and cohesion energy density) is presented in detail.

关键词： Discrete element method Angle of repose Cohesive bulk material Calibration

Real-Time Watercolor for Animation

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Journal of Computer Science & Technology 2006年第2期21卷 159-165页

作者： thomas Luft Oliver Deussen Depurtment of Computer and Information Science University of KonstanzKonstanzGermang

We present algorithms that allow for reat-time rendering of 3D-scenes with a watercolor painting appearance,Our approach provides an appropriate simplification of the visual complexity,initates characteristic natural effects of watercolor,and provides two essential painting techniques,the wet-on-wet and the wet-on-dry *** concentrate on efficient algorithms based on image space processing rather than on an exact *** allows for the real-time rendering of *** an animation a high frame-to-frame coherence can be achieved due to a stable segmentation ***,we seamlessly integrate a smooth illumination into the watercolor renderings nsing information from the 3D-scenc.

关键词： non-photorealistic rendering watercolor painting,real-time rendering

Nanoscale 3D ordered polymer networks

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Science China Chemistry 2018年第1期61卷 25-32页

作者： Edwin L. thomas Department of Materials Science and NanoEngineering Rice University Houston TX 77030 USA

Structures having nanoscale 3D geometries are valuable as multifunctional materials, where multi-continuous microphases can synergistically influence mechanical, optical, transport and other properties. Such very high interface surface to volume ratio structures occur in a variety of materials including natural materials such as butter fly wings and sea urchin exoskeletons and in synthetic self-assembled structures such as surfactant/water systems and block polymers. Quantitative morphological characterization of such complex geometric structures is quite challenging. Unit cell sizes range from 10-300 nm with corresponding feature sizes on the 2-50 nm scale. Since these nanoscale network structures are bicontinuous, when one constituent is removed, the structure is still self supporting. Removal of one component produces a nanoporous material that may be in-filled with another component, or the surfaces of the nanopores can be coated with ultra-thin layers by atomic layer deposition to offer multiftmctional capabilities. Due to the ability to individually tailor the properties of the network（s） and matrix, for example, to create strong dielectric or impedance contrast, such spatially periodic structures are excellent for the interference of waves （electromagnetic for photonic applications and acoustic for phononic applications） that can lead to bandgaps and hence the control of wave propagation in the material. This mini-review will focus on networks formed by bottom up self assembly of block polymers. In addition to structural issues, we emphasize the special physical properties related to bi- or tri-continuous networks.

关键词： self assembly block polymer network morphologies bicontinuous

RF channel performance assessment for a multiple carrier millimeter-wave communication system

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Progress in Natural Science:Materials International 2004年第10期14卷 45-48页

作者： thomas WONG Chicago Department of Electrical and Computer Engineering Illinois Institute of Technology Illinois60616 U.S.A

Channel capacity,system versatility and ease of maintenance are factors of prime concern in future generations of wire-less communication *** a result,millimeter-wave can offer considerable advantages in providing broadband *** and noise effects,including parametric fluctuations,are two significant causes for signal degradation in broadband communication *** methods to assess the performance of an RF channel in a multi-carrier system are *** measuring the forward transfer func-tion from transmitter IF to receiver IF as the frequency is swept across the channel bandwidth,characteristics such as gain flatness,chan-nel dispersion,and saturation effects are *** evaluate the ability of the communication link in preserving the synchronization be-tween two carriers,their heterodyned spectrum at the receiver IF output is *** measurement methods employ standard equip-ment and have been found to be effective when applied to a multi-carrier millimeter-wave system with over1GHz instantaneous band-width.

关键词： millimeter-wave communication system multiple carrier intermodulation carrier fluctuation synchronization

Strategically designing layered two-dimensional SnS_(2)-based hybrid electrodes: A futuristic option for low-cost supercapacitors

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Journal of Energy Chemistry 2023年第10期85卷 394-417,I0011页

作者： Susmi Anna thomas Jayesh Cherusseri Centre for Advanced Functional Materials(CAFM) Department of PhysicsBishop Moore CollegeMavelikaraKerala 690110India Sunway Centre for Electrochemical Energy and Sustainable Technology(SCEEST) School of Engineering and TechnologySunway UniversityNo.5 Jalan UniversityBandar SunwayPetaling Jaya 47500Malaysia

Supercapacitors are promising energy storage devices in current century due to their high specific capacitance, cyclic stability, high power density, and high voltage rating. Due to their excellent electrochemical properties, supercapacitors are invariably used in a multitude of applications ranging from portable electronics to electric vehicles. The electrochemical performance of a supercapacitor mainly depends on the type of electrode-active material used in it. Thereby a careful selection is mandatory to achieve the excellency. Nanostructured electrode-active materials such as carbon nanomaterials, transition metal oxides,transition metal dichalcogenides(TMDs), electronically conducting polymers, etc. are invariably used for supercapacitor application. Among these, TMDs have received great interest, particularly transition metal disulfides such as molybdenum disulfide, tin disulfide(SnS_(2)), etc. Tin is abundant on the earth with excellent charge storage capabilities, attracted great scientific interest for application as electrode materials in supercapacitors. Good electronic conductivity, long cycling life and low-cost are its added ***, we discuss the recent trends in layered two-dimensional(2D) SnS_(2)-based electrodes to develop low-cost supercapacitors. Initially, their crystal structure, basic properties, synthesis methods are discussed. Further, strategically designing electrode nanostructures to achieve excellent electrochemical performance is reviewed then after. This includes material design in terms of morphology, pore-size,and shape as well as preparation of 2D SnS_(2)-based nanocomposite electrodes. Furthermore, the challenges and future perspectives of 2D SnS_(2)-based supercapacitors are included.

关键词： SnS_(2) Supercapacitor Transition metal dichalcogenides Electrochemical energy storage

Muscle function, physical performance and body composition changes in men with prostate cancer undergoing androgen deprivation therapy

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Asian Journal of Andrology 2012年第2期14卷 204-221页

作者： thomas W Storet Renee Miciek thomas G Travison Section of Endocrinology Diabetes and Nutrition Boston University School of Medicine Boston MA 02118 USA

Prostate cancer （PCa） is the most common visceral malignancy in men with androgen deprivation therapy （ADT） the preferred therapy to suppress testosterone production and hence tumor growth. Despite its effectiveness in lowering testosterone, ADT is associated with side effects including loss of muscle mass, diminished muscle strength, decrements in physical performance, earlier fatigue and declining quality of life. This review reports a survey of the literature with a focus on changes in muscle strength, physical function and body composition, due to short-term and long-term ADT. Studies in these areas are sparse, especially well-controlled, prospective randomized trials. Cross-sectional and longitudinal data （up to 2 years） for men with PCa treated with ADT as well as patients with PCa not receiving ADT and age-matched healthy men are presented when available. Based on limited longitudinal data, the adverse effects of ADT on muscle function, physical performance and body composition occur shortly after the onset of ADT and tend to persist and worsen over time. Exercise training is a safe and effective intervention for mitigating these changes and initial guidelines for exercise program design for men with PCa have been published by the American College of Sports Medicine. Disparities in study duration, types of studies and other patient-specific variables such as time since diagnosis, cancer stage and comorbidities may all affect an understanding of the influence of ADT on health, physical performance and mortality.

关键词： androgen deprivation therapy androgen suppression exercise prescription exercise training functional assessment lean body mass older men prostate cancer

A plant-based diet and animal protein： questioning dietary fat and consideringanimal protein as the main cause of heart disease

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Journal of Geriatric Cardiology 2017年第5期14卷 331-337页

作者： thomas Colin Campbell Emeritus of Nutritional Biochemistry Cornell University 8 Fiddlers Green Lansing NY 14882 USA.

Dietary ＇fat＇（e.g., oils, triglycerides, cholesterol） haslong been considered a major risk factor for cardiovascularand related diseases. As reviewed elsewhere,Vogel in1847 identified cholesterol as a major compo... 详细信息

关键词： Cardiovascular disease Cholesterol Dietary protein

Traditional grazing management creates heterogeneous swards and fosters grasshopper densities

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Insect Science 2022年第6期29卷 1805-1818页

作者： Cinja Schwarz thomas Fartmann Department of Biodiversity and Landscape Ecology Faculty of Biology and ChemistryOsnabruck UniversityOsnabruckGermany

Common pastures were once the dominant type of land use in many Euro-pean ***,during the past 150 years,they have declined *** studies have shown that they are hotspots for rare plant,butterfly,and bird species in the study area,the Bavarian pre-Alps(southern Germany).However,studies on the value of these pastures for Orthoptera(hereinafter termed"grasshoppers")have been ***,we studied the effects of traditional summer grazing in common pastures on grasshopper *** study revealed that grasshopper species richness did not differ between common pastures(n=57)and controls(n=57).By contrast,density of all and of threat-ened species varied between common pastures and controls in all plots and within the two vegetation types with the highest grasshopper abundance,grasslands on mineral soil and *** threatened species,Pseudochorthippus montanus and Stethophyma grossum,were identified as indicators for common pastures;controls had no indicative *** low-intensity grazing in common pastures has resulted in open and heteroge-neous swards with some bare ground,a low cover of litter and an intermediate vegetation height favouring high densities of grasshopper species in general and threatened species in *** is especially true for the two most productive vegetation types,grasslands on mineral soil and *** promote biodiversity in general and grasshopper densities in particular,we recommend maintaining traditional cattle grazing(stocking capacities:0.5-2.0 livestock units/ha)in common *** possible,this grazing regime should also be introduced in the surrounding landscape.

关键词： biodiversity conservation common pasture habitat heterogeneity insect abundance land-usechange mire ecosystem

Complexities and pitfalls in analyzing and interpreting mitochondrial DNA content in human cancer

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Journal of Genetics and Genomics 2020年第7期47卷 349-359页

作者： Hieu Nguyen thomas LaFramboise Vinmec Research Institute of Stem Cell and Gene Technology(VRSIG) 458 M inh KhaiVinh TuyHai Ba TrungHanoiViet Nam Department of Genetics and Genome Sciences Case Western Reserve University School of Medicine10900 Euclid AvenueClevelandOH44106USA

Mutations in the human mitochondrial genome have been observed in all types of human cancer,indicating that mutations might contribute to tumorigenesis,metastasis,recurrence,or drug *** possibility is appealing because of the known shift from oxidative metabolism to glycolysis,known as the Warburg effect,that occurs in *** DNA(mtDNA)mutations could either bematernally inherited and predispose to cancer(germ line mutations)or occur sporadically in the mtDNA of specific tissues(rissue-or tumor-specific somatic mutations)and contribute to the tumor initiation and progression ***-throughput sequencing technologies now enable comprehensive detection of mtDNA variation in tissues and bodily fluids,with the potential to be used as an early detectiontool that may impact the treatment of ***,we discuss insights into the roles of mtDNA mutations in carcinogenesis,highlighting the complexities involved in the analysis and interpretation of mitochondrial genomic *** challenges in studying their contribution to pathogenesis,and the value of mtDNA mutations in developing early detection,diagnosis,prognosis,and therapeuticstrategics for cancer.

关键词： Mitochondrial DNA Cancer Genetic variation