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Mechanisms and anisotropy of serrated flow in Mg-Gd single crystals

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Journal of Magnesium and Alloys 2023年第5期11卷 1643-1655页

作者： henry Ovri Helmholtz Zentrum Hereon Institute of Materials Mechanics21502 GeesthachtGermany

Serrated flow has been primarily studied at the macron scale,yet the length and times scales at which the solute-meditated dislocation pinning and de-pinning processes that underlie the phenomenon occur are largely inaccessible by macroscopic ***,direct insights into the dominant slip systems in the serrated flow regime,which is particularly critical in Mg alloys given their high plastic anisotropy,requires the use of small-scale testing methods such as ***,in this work,a combination of microcompression and TEM based EDS/STEM measurements have used to critically study the temperature and strain rate dependences in single crystals of pure Mg and a Mg-Gd alloy oriented for twinning,basal-,prismatic-,and *** results provide compelling evidence that the solute drag mechanism underlie serrated flow in the alloy;they also show that serrated flow in Mg alloys is markedly *** anisotropy is caused by differences between the Burgers vector for slip/twinning,and between the impurity diffusivity along/perpendicular to the basal plane.

关键词： Microcompression Mg-RE Mg-Gd Pure Mg Serrated flow Solute drag STEM

Microenvironmental engineering:An effective strategy for tailoring enzymatic activities

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Chinese Journal of Chemical Engineering 2020年第8期28卷 2028-2036页

作者： Yifei Zhang henry Hess Department of Biomedical Engineering Columbia University351L Engineering Terrace1210 Amsterdam AvenueNew YorkNY 10027USA

Rationally,engineering a favorable physicochemical microenvironment for enzymes has recently emerged as an effective strategy to improve their catalytic *** this review,we discuss four microenvironmental effects according to the mechanism of action:localizing and excluding reactants and regulators,regulating microenvironmental pH,creating a water-like microenvironment,and increasing the local *** mechanisms are enzyme-independent and can in principle be used in combination to tailor enzyme behaviors,offering new approaches to enabling,enhancing,and regulating enzyme catalysis in diverse applications without the need for genetic engineering.

关键词： Biocatalysis Enzyme Microenvironment Activity enhancement

Efficiency of the motion amplification device with viscous dampers and its application in high-rise buildings

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Earthquake Engineering and Engineering Vibration 2009年第4期8卷 521-536页

作者： henry C.Huang WSP Asia Ltd.

After nearly a decade of application and investigation, a motion amplification device with viscous dampers for energy dissipation has been recognized as an effective solution to mitigate wind or seismic excitation, especially for stiff structural systems. As a result of compensation of amplified motion, it has been proved that the efficiency of viscous damper largely depends on the motion amplification device configuration, particularly for device stiflhess. In this paper, a ＂scissor-jack＂ type of motion amplification device, called a ＂toggle brace damper＂ system, is studied. It is demonstrated that the efficiency of such a device reflected by its amplification factor is not merely a function of its geometric configuration, but is highly dependent on the support elements＇ stiffness as well, similar to the mechanism of a leverage arm. Accordingly, a mathematical model in terms of complex modulus of the viscous damper with consideration of the support brace＇s stiffness is established. The results indicate that the efficiency of the motion amplification device with viscous dampers significantly depends on the stiffness of the support elements. Other parameters, such as toggle brace configuration and damping values of the viscous damper, are studied and compared. As an application example, numerical analyses are conducted to study the dynamic performance of a 39-story office tower installed with toggle brace dampers constructed on soft soil in a reclaimed area, under a combined effect of the vortex shedding of an adjacent existing 52-story building and earthquakes. The results show that viscous dampers with a motion amplification system using a properly designed toggle brace device proved to be an effective solution to alleviate the external excitations.

关键词： motion amplification device vibration mitigation viscous damper energy dissipation toggle brace damper

THREE-DIMENSIONAL AXISYMMETRIC FLOW IN PERFECTLY PLASTIC METALS

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Acta Mechanica Sinica 1993年第4期9卷 337-344页

作者： henry Vaughan 黄筑平 University of British Columbia VancouverV6T 1W5 Canada Peking University Beijing China 100871

A method is presented for solving the three-dimensional axisymmet- ric field equations for a perfectly plastic material which obeys the von-Mises yield criterion and the Levy-Mises flow law. The method is used for the particular case in which a small axisymmetric perturbed flow is superposed on a uniform flow without flow reversal taking place. The method then leads to solving a fourth order differen- tial equation for the velocity potential. The special case of a thick cylindrical shell under compressive flow is examined. The solution so obtained, being derived from the three dimensional theory, includes a correct treatment of transverse shear distor- tion. A preferred mode of instability is identified having a wave-length in reasonable agreement with that obtained experimentally by other workers.

关键词： plastic buckling preferred mode of instability moderately thick cylindrical shell

Hemostatic agents for prehospital hemorrhage control: a narrative review

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Military Medical Research 2020年第4期7卷 444-463页

作者： henry T.Peng Defence Research and Development Canada Toronto Research Centre1133 Sheppard Avenue WestTorontoON M3K 2C9Canada

Hemorrhage is the leading cause of preventable death in combat trauma and the secondary cause of death in civilian trauma.A significant number of deaths due to hemorrhage occur before and in the first hour after hospital arrival.A literature search was performed through PubMed,Scopus,and Institute of Scientific Information databases for English language articles using terms relating to hemostatic agents,prehospital,battlefield or combat dressings,and prehospital hemostatic resuscitation,followed by cross-reference *** were screened to determine relevance and whether appropriate further review of the original articles was *** on these findings,this paper provides a review of a variety of hemostatic agents ranging from clinically approved products for human use to newly developed concepts with great potential for use in prehospital *** hemostatic agents can be administered either systemically or locally to stop bleeding through different mechanisms of *** of current hemostatic products and further directions for prehospital hemorrhage control are also discussed.

关键词： Hemostatic agent Hemorrhage control Trauma

A step forward in breeding for ratooning ability in rice

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Molecular Plant 2024年第3期17卷 368-369页

作者： Amelia henry Rice Breeding Innovations Department International Rice Research InstituteLos BanosLagunaPhilippines

Rice ratoon cropping,or the cultivation of tillers that have regrown from existing stem nodes of a harvested crop,is currently a hot topic in agriculture,and record-high ratoon crop yields have been achieved in China(Xu et al.,2021).Although rice ratoon cropping is most appropriate for certain agro-ecosystems with a suitable climate and cropping schedule,it is a promising strategy to simultaneously increase productivity while reducing inputs and *** ratoon cropping may thereby contribute to global food security and agro-ecosystem sustainability.

关键词： breeding cropping thereby

Innovations in Agriculture and Food Supply in Response to the COVID-19 Pandemic

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Molecular Plant 2020年第8期13卷 1095-1097页

作者： Robert henry Queensland Alliance for Agriculture and Food Innovation University of QueenslandBrisbaneQLD 4072 Australia

In human history,the long-term expansion of populations has been limited by the availability of food and constraints of disease(Diamond,1997).The domestication of plants and animals has facilitated the development of human societies,and the resulting larger human populations have increased the risk of major disease outbreaks(pandemics).The recent COVID-19 pandemic resulted from the emergence of a disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).This has caused major disruption to economic activity with severe restrictions on international *** impact on agriculture and global food security will be complex(Torero,2020),and many of the consequences are yet to be identified and understood(Jámbor et al.,2020).Despite growing stocks of foods such as cereals(FAO,2020),it has been estimated that the number of people facing a food crisis will grow from 135 million to 265 million by the end of 2020(Anthem,2020;Figure 1).The pandemic has added to the food security challenges posed by climate change and major conflicts,both of which have been major factors contributing to recent food *** scientists need to determine how investment in innovation needs to change in response to the *** about shortages of labor and food safety will intensify efforts to use automation at all stages in the food production system to ensure supply.

关键词： Figure travel consequences

GIS based ArcPRZM-3 model for bentazon leaching towards groundwater

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Journal of Environmental Sciences 2010年第12期22卷 1854-1859页

作者： Tahir Ali Akbar henry Lin College of Natural Resources University of Wisconsin-Stevens Point Department of Civil Engineering Schulich School of EngineeringUniversity of Calgary2500 University Drive NWCalgaryAlbertaT2N 1N4Canada Department of Crop and Soil Sciences The Pennsylvania State UniversityUniversity ParkPA 16802USA

Groundwater contamination due to pesticide applications on agricultural lands is of great environmental concern. The mathematical models help to understand the mechanism of pesticide leaching in soils towards groundwater. We developed a user-friendly model called ArcPRZM-3 by integrating widely used Pesticide Root Zone Model version 3 （PRZM-3） using Visual Basic and Geographic Information System （GIS） based Avenue programming. ArcPRZM-3 could be used to simulate pesticide leaching towards groundwater with user-friendly input interfaces coupled with databases of crops, soils and pesticides. The outputs from ArcPRZM-3 could be visualized in user-friendly formats of tables, charts and maps. In this study we evaluated ArcPRZM-3 model by simulating bentazon leaching in soil towards groundwater. ArcPRZM-3 was applied to 37 sites in Woodruff County, Arkansas, USA to observe the daily average dissolved bentazon concentration for soybean, sorghum and rice at a depth of 1.8 m for a period of two years. Nineteen ranks of bentazon leaching potential were obtained using ArcPRZM-3 for all sites having different soil and crop combinations. ArcPRZM-3 simulation results for bentazon were compatible with the field monitored data in term of relative ranking and trend, although some uncertainties exist. This study indicated that macropore flow mechanism would be important in analyzing the effect of irrigation on groundwater contamination due to pesticides. Overall, ArcPRZM-3 could be used to simulate pesticide leaching towards groundwater more efficiently and effectively as compared to PRZM-3.

关键词： ArcPRZM-3 PRZM-3 GIS pesticide leaching groundwater contamination bentazon

Conditional Coverage Estimation for High-Quality Prediction Intervals

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Journal of Systems Science and Systems Engineering 2023年第3期32卷 289-319页

作者： Ziyi Huang henry Lam Haofeng Zhang School of Engineering and Applied Science Columbia UniversityNew YorkNY 10027USA

Deep learning has been recently studied to generate high-quality prediction intervals(PIs)for uncertainty quantification in regression tasks,including recent applications in simulation *** high-quality criterion requires PIs to be as narrow as possible,whilst maintaining a pre-specified level of data(marginal)***,most existing works for high-quality PIs lack accurate information on conditional coverage,which may cause unreliable predictions if it is significantly smaller than the marginal *** address this problem,we propose an end-to-end framework which could output high-quality PIs and simultaneously provide their conditional coverage *** doing so,we design a new loss function that is both easy-to-implement and theoretically justified via an exponential concentration *** evaluation on real-world benchmark datasets and synthetic examples shows that our approach not only achieves competitive results on high-quality PIs in terms of average PI width,but also accurately estimates conditional coverage information that is useful in assessing model uncertainty.

关键词： Uncertainty quantification prediction intervals conditional coverage neural networks calibrationerror