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TBCs for Gas Turbines under Thermomechanical Loadings： Failure Behaviour and Life Prediction

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Journal of Energy and Power Engineering 2013年第4期7卷 647-653页

作者： Tilmann Beck Olena Trunova roland herzog Lorenz Singheiser Forschungszentrum Juelich GmbH Institute of Energy and Climate Research Juelich 52425 Germany RM-Material Technology MAN Diesel & Turbo SE Oberhausen 46145 Germany

The present contribution gives an overview about recent research on a TBC （thermal barrier coating） system consisted of （I） an intermetallic MCrAIY-alloy BC （bond coat） applied by VPS （vacuum plasma spraying） and （2） an YSZ （yttria stabilised zirconia） top coat APS （air plasma sprayed） at Forschungszentrum Juelich, Institute of Energy and Climate Research （IEK-2）. The influence of high temperature dwell time, maximum and minimum temperature on crack growth kinetics during thermal cycling of such plasma sprayed TBCs is investigated using scanning electron microscopy and AE （acoustic emission） analysis. Thermocyclic life in terms of accumulated time at maximum temperature decreases with increasing high temperature dwell time and increases with increasing minimum temperature. AE analysis proves that crack growth mainly occurs during cooling at temperatures below the ductile-to-brittle transition temperature of the BC. Superimposed mechanical load cycles accelerate delamination crack growth and, in case of sufficiently high mechanical loadings, result in premature fatigue failure of the substrate. A life prediction model based on TGO growth kinetics and a fracture mechanics approach has been developed which accounts for the influence of maximum and minimum temperature as well as of high temperature dwell time with good accuracy in an extremely wide parameter range.

关键词： Thermal barrier coating spallation failure crack propagation thermomechanical fatigue lifetime prediction.

Why are muscles strong, and why do they require little energy in eccentric action?

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Journal of Sport and Health Science 2018年第3期7卷 255-264页

作者： Walter herzog Human Performance Laboratory Faculty of Kinesiology University of Calgary

It is well acknowledged that muscles that are elongated while activated(i.e.,eccentric muscle action)are stronger and require less energy(per unit of force)than muscles that are shortening(i.e.,concentric contraction)or that remain at a constant length(i.e.,isometric contraction).Although the cross-bridge theory of muscle contraction provides a good explanation for the increase in force in active muscle lengthening,it does not explain the residual increase in force following active lengthening(residual force enhancement),or except with additional assumptions,the reduced metabolic requirement of muscle during and following active *** from the cross-bridge theory,2 other primary explanations for the mechanical properties of actively stretched muscles have emerged:(1)the so-called sarcomere length nonuniformity theory and(2)the engagement of a passive structural element *** this article,these theories are discussed,and it is shown that the last of these—the engagement of a passive structural element in eccentric muscle action—offers a simple and complete explanation for many hitherto unexplained observations in actively lengthening *** by no means fully proven,the theory has great appeal for its simplicity and beauty,and even if over time it is shown to be wrong,it nevertheless forms a useful framework for direct hypothesis testing.

关键词： Cross-bridge theory Eccentric Force-length relationship Residual force enhancement Titin

High rate of complicated idiopathic gallstone disease in pediatric patients of a North American tertiary care center

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World Journal of Gastroenterology 2008年第10期14卷 1544-1548页

作者： Denise herzog Guylaine Bouchard Division of Gastro-enterology and Nutrition Sainte Justine Hospital University of Montreal Montreal Quebec Canada

AIM: To assess spectrum and etiology of gallstones and biliary sludge in the pediatric population of a North American tertiary care centre. METHODS: Retrospective review of abdominal ultraso- unds recorded at Saint Justine Hospital over a period of 24 mo (8/2003 to 8/2005) in patients 2 years of age idiopathic gallstone disease was found. These 48 patients represent 2.1% of the population who required ultrasound for abdominal pain. Complicated gallstone disease occurred in 28/48 with idiopathic disease, mainly adolescent girls. Patients with hemolytic disorders, cystic fibrosis, oncologic diseases or kidney transplantation and gallstones were asymptomatic and stones were detected during routine abdominal ultrasound. Twenty two patients < 2 years of age not consulting for abdominal pain had gallstone disease of diverse etiology. Biliary sludge was seen in 84 patients, 78.5% on total parenteral nutrition. In 4 patients, sludge progressed to gallstones. CONCLUSION: Idiopathic gallstone disease and its rate of complication are more frequent in our cohort than expected from previous studies. Adolescent girls with abdominal pain and idiopathic gallstones require special attention for complicated disease course.

关键词： Cholecystectomy Hemolytic disease Cystic fibrosis Pancreatitis Choledocholithiasis

Alternative fuels—a new field for mine surveying

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中国有色金属学会会刊：英文版 2005年第S1期15卷 289-293页

作者： A. Preuβe C. herzog Institute for Mine Surveying Mining Subsidence Engineering and Geophysics in Mining (IFM) RWTH Aachen University Wüllnerstr. 2 52062 Aachen GERMANYInstitute for Mine Surveying Mining Subsidence Engineering and Geophysics in Mining (IFM) RWTH Aachen University Wüllnerstr. 2 52062 Aachen GERMANY

Due to the public’s increased interest in renewable energies and the “Erneuerbare Energien Gesetz” (EEG) from February 2000, geothermal energy and other alternative or renewable energies gain more and more importance. As far as Germany is concerned, geothermal energy and coal bed/mine methane are considered as mineral resources according to the German mining law. This demands the participation of mine surveyors/mineral resources managers from the planning to the production stage and even beyond it. The main tasks that have to be fulfilled are, among others, applications for exploration and production licences as well as the evaluation of the resource’s potential. This paper indicates the tasks of mine surveyors/mineral resources managers in the wide area of the renewable energies in Germany, especially concerning the use of geothermal energy and methane.

关键词： mine surveying mineral resources management renewable energies geothermal energy methane

The secrets to running economy

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Journal of Sport and Health Science 2022年第3期11卷 273-274页

作者： Walter herzog Human Performance Laboratory Faculty of KinesiologyUniversity of CalgaryCalgaryAB T2N 1N4Canada

Every once in a while,a sport is revolutionized by a discovery or a new *** the mid-1980s,cross-country skiing was changed forever by the introduction of the skating *** Fosbury revolutionized high-jumping when he won the Olympic Games by crossing the bar“backwards”,and the development of the“klapp-skate”led to vast improvements of world records in speed skating.

关键词： technique. backward revolution

Eccentric vs. concentric muscle contraction： That is the question

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Journal of Sport and Health Science 2017年第2期6卷 128-129页

作者： Walter herzog Human Performance Laboratory Faculty of KinesiologyUniversity of Calgary

In their recent papers in the Journal of Sport and Health Science on hamstring injuries in sprinting,^(1,2)and their corresponding commentaries on each other's research,3,4Yu et *** Liu et *** different views of the mechanisms of muscle injuries in general,and hamstring injuries in sprinting *** Yu et al.^(1,3)argued that muscle injuries are primarily,if not exclusively,caused by muscle strain magnitude in eccentric contractions,and thus hamstring injuries occur primarily

关键词：心肌收缩偏心肌肉损伤收缩应变受伤短跑

Homology of Powers of Ideals： Artin-Rees Numbers of Syzygies and the Golod Property

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Algebra Colloquium 2016年第4期23卷 689-700页

作者： Jiirgen herzog Volkmar Welker Siamak Yassemi Fachbereich Mathematik Universitat Duisburg-Essen Campus Essen 45117 Essen Germany Philipps-Universitat Marburg Fachbereich Mathematik und Informatik 35032 Marburg Germany School of Mathematics Statistics and Computer Science College of Science University of Tehran Tehran Iran

Let Ro be a Noetherian local ring and R a standard graded R0-algebra with maximal ideal ra and residue class field K = Rim. For a graded ideal I in R we show that for k 〉〉 0：（1） the Artin-Rees number of the syzygy modules of Ik as submodules of the free modules from a free resolution is constant, and thereby the Artin-Rees number can be presented as a proper replacement of regularity in the local situation; and （2） R is a polynomial ring over the regular Ro, the ring R/Ik is Golod, its Poincar4-Betti series is rational and the Betti numbers of the free resolution of K over R/I^k are polynomials in k of a specific degree. The first result is an extension of the work by Swanson on the regularity of I^k for k 〉〉 0 from the graded situation to the local situation. The polynomiality consequence of the second result is an analog of the work by Kodiyalam on the behaviour of Betti numbers of the minimal free resolution of R/Ik over R.

关键词： Artin-Rees numbers syzygies Golod rings Betti numbers deviations

Editorial re:Could sport be part……by Ring-Dimitriou et al.

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Journal of Sport and Health Science 2019年第4期8卷 348-349页

作者： Walter herzog Human Performance Laboratory Faculty of KinesiologyUniversity of Calgary

Childhood obesity has become a concern in most economically developing *** reasons for this seem clear:too much food and not enough *** dilemma has received much scientific attention,and the question arises:How do we get children to move and make good eating choices?In their opinion piece in this issue of the Journal of Sport and Health Science(JSHS),Ring-Dimitriou et al.1 make an argument that playing structured and supervised traditional sports will help children with obesity,where traditional sports include football,handball,gymnastics,athletics,and martial arts.

关键词： Ring-Dimitriou Journal of Sport and Health Science(JSHS) economically developing countries

Do recreational team sports provide fitness and health benefits?

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Journal of Sport and Health Science 2018年第2期7卷 127-128页

作者： Walter herzog Human Performance Laboratory Faculty of KinesiologyUniversity of Calgary

In many countries,sedentary lifestyle has led to a number of epidemic health problems,including obesity,metabolic syndrome,and associated *** have performed self-evaluations of the fitness status of their people:child... 详细信息

关键词：健康问题运动娱乐生活方式新陈代谢自我评估症候群成年人