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Simulating orthokinetic heterocoagulation and cluster growth in destabilizing suspensions

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Particuology 2017年第2期15卷 117-128页

作者： Fabian Billow hermann Nirschl Willy Dorfler Institute of Mechanical Process Engineering and Mechanics Karlsruhe Institute of Technology 76131 Karlsruhe Germany Institute for Applied and Numerical Mathematics Karlsruhe Institute of Technology 76131 Karlsruhe Germany

Using direct numerical simulation, we investigate the coagulation behavior of non-Brownian colloidal particles as exemplified by Al2O3 particles. This yields the so-called capture efficiency, for which we give an analytical expression, as well as other time-dependent variables such as the cluster growth rate. Instead of neglecting or strongly approximating the hydrodynamic interactions between particles, we include hydrodynamic and non-hydrodynamic interactions in a Stokesian dynamics approach and a comprehensive modeling of the interparticle forces. The resulting parallelized simulation framework enables us to investigate the dynamics of polydisperse particle systems composed of several hundred particles at the same high level of modeling we used for a close investigation of the coagulation behavior of two unequal particles in shear flow. Appropriate cluster detection yields all the information about large destabilizing systems, which is needed for models used in flow-sheet simulations. After non-dimensionalization, the results can be generalized and applied to other systems tending to secondary coagulation

关键词： Destabilization Coagulation Capture efficiency Al2O3 Cluster detection Stokesian dynamics

Overview of Particles and Bubbles in Continuously Cast Steel

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Journal of Iron and Steel Research International 2011年第S2期18卷 211-219页

作者： Karl-hermann TACKE AG der Dillinger Hüttenwerke P.O. Box 1580 D-66748 Dillingen/Saar Germany

This paper gives an overview of phenomena associated with particles and bubbles in continuously cast steel. During steel processing from deoxidation to solidification the inclusion population undergoes changes with opportunities of removal. Flotation is an important separation mechanism. Inclusion particles may accumulate in the solidifying strand, thus forming enriched bands, which depend on the type of casting machine. Bubbles are created during inert gas injection. They also change in size, can float out, but also form accumulation bands. The interaction of bubbles and particles is discussed. Internal structure that recently has been observed on the inner surface of bubbles will be reviewed.

关键词： continuous casting solidification inclusions particles agglomeration accumulation bands gas injection bubbles attachment flotation inner surface wave rings terraces

Influence of drag laws on pressure and bed material recirculation rate in a cold flow model of an 8 MW dual fluidized bed system by means of CPFD

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Particuology 2018年第1期16卷 70-81页

作者： Stephan Kraft Friedrich Kirnbauer hermann Hofbauer Bioenergy 2020+ GmbH Wiener Strasse 49 A- 7540 Gussing Austria TU Wien Institute of Chemical Engineering Getreidemarkt 9/166 Vienna Austria

A cold flow model of an 8 MW dual fluidized bed （DFB） system is simulated using the commercial compu- tational particle fluid dynamics （CPFD） software package Barracuda. The DFB system comprises a bubbling bed connected to a fast fluidized bed with the bed material circulating between them. As the hydrodynam- ics in hot DFB plants are complex because of high temperatures and many chemical reaction processes, cold flow models are used. Performing numerical simulations of cold flows enables a focus on the hydro- dynamics as the chemistry and heat and mass transfer processes can be put aside. The drag law has a major influence on the hydrodynamics, and therefore its influence on pressure, particle distribution, and bed material recirculation rate is calculated using Barracuda and its results are compared with experimental results. The drag laws used were energy-minimization multiscale （EMMS）, Ganser, Turton-Levenspiel, and a combination of Wen-Yu]Ergun. Eleven operating points were chosen for that study and each was calculated with the aforementioned drag laws. The EMMS drag law best predicted the pressure and dis- tribution of the bed material in the different parts of the DFB system. For predicting the bed material recirculation rate, the Ganser drag law showed the best results. However, the drag laws often were not able to predict the experimentally found trends of the bed material recirculation rate. Indeed, the drag law significantly influences the hydrodynamic outcomes in a DFB system and must be chosen carefully to obtain meaningful simulation results. More research may enable recommendations as to which drag law is useful in simulations ofa DFB system with CPFD.

关键词： Cold flow modeling Fluidization Computational particle fluid dynamics(CPFD) simulation Dual fluidized bed Computational fluid dynamics

A language to analyze, describe, and explore collections of visual art

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Visual Computing for Industry,Biomedicine,and Art 2021年第1期4卷 29-49页

作者： hermann Pflüger Institute for Visualization and Interactive Systems University of Stuttgart70569 StuttgartGermany

A vast quantity of art in existence today is inaccessible to *** people want to know the different types of art that exist,how individual works are connected,and how works of art are interpreted and discussed in the context of other works,they must utilize means other than simply viewing the ***,this paper proposes a language to analyze,describe,and explore collections of visual art(LadeCA).LadeCA combines human interpretation and automatic analyses of images,allowing users to assess collections of visual art without viewing every image in *** paper focuses on the lexical base of *** also outlines how collections of visual art can be analyzed,described,and explored using a LadeCA ***,the relationship between LadeCA and indexing systems,such as ICONCLASS or AAT,is demonstrated,and ways in which LadeCA and indexing systems can complement each other are highlighted.

关键词： Collections of visual art Visual computing Personalized digital libraries Digital humanities Semantics

Modeling Spatio-temporal Drought Events Based on Multi-temporal,Multi-source Remote Sensing Data Calibrated by Soil Humidity

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Chinese Geographical Science 2022年第1期32卷 127-141页

作者： LI Hanyu KAUFMANN hermann XU Guochang Institute of Space Science and Applied Technology Harbin Institute of Technology(Shenzhen)Shenzhen 518000China Remote Sensing Section German Research Centre for Geosciences(GFZ)Potsdam 14473Germany

Inspired by recent significant agricultural yield losses in the eastern China and a missing operational monitoring system,we developed a comprehensive drought monitoring model to better understand the impact of individual key factors contributing to this *** resulting model,the‘Humidity calibrated Drought Condition Index’(HcDCI)was applied for the years 2001 to 2019 in form of a case study to Weihai County,Shandong Province in East *** and development are based on a linear combination of the Vegetation Condition Index(VCI),the Temperature Condition Index(TCI),and the Rainfall Condition Index(RCI)using multi-source satellite data to create a basic Drought Condition Index(DCI).VCI and TCI were derived from MODIS(Moderate Resolution Imaging Spectroradiometer)data,while precipitation is taken from CHIRPS(Climate Hazards Group InfraRed Precipitation with Station data)*** reasons of accuracy,the decisive coefficients were determined by the relative humidity of soils at depth of 10-20 cm of particular areas collected by an agrometeorological ground *** correlation between DCI and soil humidity was optimized with the factors of 0.53,0.33,and 0.14 for VCI,TCI,and RCI,*** model revealed,light agricultural droughts from 2003 to 2013 and in 2018,while more severe droughts occurred in 2001 and 2002,2014-2017,and *** droughts were most severe in January,March,and December,and our findings coincide with historical *** average temperature during 2012-2019 is 1℃ higher than that during the period 2001-2011 and the average precipitation during 2014-2019 is 192.77 mm less than that during *** spatio-temporal accuracy of the HcDCI model was positively validated by correlation with agricultural crop yield *** model thus,demonstrates its capability to reveal drought periods in detail,its transferability to other regions and its usefulness to take future measures.

关键词： comprehensive drought model condition indices multi-source satellite data agricultural drought soil humidity

Complex RNA-DNA hybrid nanoshapes from iterative mix-andmatch screening

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Nano Research 2021年第1期14卷 46-51页

作者： Shi Chen Zhiyuan Zhang Eugene Alforque Thomas hermann Department of Chemistry and Biochemistry University of CaliforniaSan DiegoCA 92093USA Center for Drug Discovery Innovation University of CaliforniaSan DiegoCA 92093USA Materials Science and Engineering Program University of CaliforniaSan DiegoCA 92093USA

Hybrid nucleic acid nanostructures partition architectural and functional roles between ribonucleic acid(RNA)joints and deoxyribonucleic acid(DNA)*** self-assemble from nucleic acid modules through synergistic stabilization of marginally stable base pairing interactions within circularly closed ***,we report the development of hybrid nanoshapes that include multiple different RNA modules such as internal loop and three-way junction(3WJ)*** iterative mix-and-match screening approach was used to identify suitable DNA connectors that furnished stable nanoshapes for combinations of different RNA *** resulting complex multicomponent RNA-DNA hybrid nanoshapes were characterized by atomic force microscopy(AFM)*** research provides proof of concept for modular design,assembly and screening of RNA-DNA hybrid nanoshapes as building blocks for complex extended nucleic acid materials with features at the sub-10 nm scale.

关键词： nucleic acid nanotechnology nanoshapes ribonucleic acid(RNA)three-way junction(3WJ) RNA deoxyribonucleic acid(DNA) sub-10 nm features

Recent results of laparoscopic surgery in inflammatory bowel disease

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World Journal of Gastroenterology 2011年第9期17卷 1116-1125页

作者： hermann Kessler Jonas Mudter Werner Hohenberger Department of Surgery University of Erlangen Department of Internal Medicine 1 GastroenterologyUniversity of Erlangen

Inflammatory bowel diseases are an ideal indication for the laparoscopic surgical approach as they are basically benign diseases not requiring lymphadenectomy and extended mesenteric excision;well-established surgical procedures are available for the conventional *** alterations and fragility of the bowel and mesentery,however,may demand a high level of laparoscopic experience.A broad spectrum of operations from the rather easy enterostomy formation for anal Crohn’s disease(CD)to restorative proctocolectomies for ulcerative colitis(UC)may be managed *** current evidence base for the use of laparoscopic techniques in the surgical therapy of inflammatory bowel diseases is *** limited to the terminal ileum has become a common indication for laparoscopic surgical *** severe anal CD, laparoscopic stoma formation is a standard procedure with low morbidity and short operative *** comparing conventional and laparoscopic bowel resections,have found shorter times to first postoperative bowel movements and shorter hospital stays as well as lower complication rates in favour of the laparoscopic *** complicated cases with previous surgery,abscess formation and enteric fistulas may be op-erated on laparoscopically with a low *** UC, restorative proctocolectomy is the standard procedure in elective *** demanding laparoscopic approach is increasingly used,however,mainly in major centers; its feasibility has been proven in various *** increased body mass index and acute inflammation of the bowel may be relative *** and longterm outcomes like quality of life seem to be equivalent for open and laparoscopic *** studies have proven that the laparoscopic approach to CD and UC is a safe and successful alternative for selected patients. The appropriate selection criteria are still under *** considerations are playing an important role for the co

关键词： Crohn’s disease Ulcerative colitis Laparoscopic Colorectal Surgery

Fused in sarcoma-amyotrophic lateral sclerosis as a novel member of DNA single strand break diseases with pure neurological phenotypes

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Neural Regeneration Research 2021年第1期16卷 110-112页

作者： Marcel Naumann Julian Laubenthal Andreas hermann Translational Neurodegeneration Section“Albrecht-Kossel” Department of NeurologyUniversity Medical Center RostockUniversity of RostockRostockGermany German Center for Neurodegenerative Diseases(DZNE)Rostock/Greifswald Center for Transdisciplinary Neurosciences Rostock(CTNR)University Medical Center RostockUniversity of RostockRostockGermany

Accumulation of DNA damage and genomic instability are believed to have crucial effects in neurodegenerative conditions such as Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,premature aging diseases as well as amyotrophic lateral sclerosis(ALS)and frontotemporal dementia(FTD).Until recently these studies were largely correlative in nature,though raising the possibility that defects in the DNA damage response(DDR)underlie neurodegenerative diseases.

关键词： diseases Huntington amyotrophic

Mechanical and Frictional Properties of the Elytra of Five Species of Beetles

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Journal of Bionic Engineering 2013年第1期10卷 77-83页

作者： Min Yu Ilja hermann Zhendong Dai Norm Gitis Institute of Bio-inspired Structure and Surface Engineering Nanjing University of Aeronauties and Astronautics Nanjing 210016 P. R. China Bruker Nano Inc. 1717 Dell Ave. Campbell CA 95008 USA

The mechanical and frictional properties of different parts of the elytra of five species of beetle were measured using a nano-indenter and a micro-tribometer. The surface microstructures of the elytra were observed by optical microscopy and scanning white light interferometry. The surface microstructures of the elytra of all five species are characterized as non-smooth concavo-convex although specific morphological differences demonstrate the diversity of beetle elytra. Young＇s modulus and the hardness of the elytral materials vary with the species of beetle and the sampling locations, ranging from 1.80 GPa to 12.44 GPa, and from 0.24 GPa to 0.75 GPa, respectively. In general, both the Young＇s modulus and the hardness are lower in samples taken from the center of the elytra than those taken from other regions, which reflects the functional heterogeneity of biological material in the process of biological evolution. The elytra have very low friction coefficient, ranging from 0.037 to 0.079, which is related to their composition and morphology. Our measurements indicate that the surface texture and its mi- crostructural size of beetle elytra contribute to anti-friction effects.

关键词： beetle elytra bio-tribology surface morphology mechanical properties