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Influence of towing speed on effectiveness of rolling dynamic compaction

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 126-134页

作者： Brendan t.Scott Mark B.Jaksa Peter w.Mitchell School of Civil Environmental and Mining EngineeringThe University of AdelaideSouth Australia5005Australia Aurecon AdelaideSouth Australia5000Australia

the influence of towing speed on the effectiveness of the 4-sided impact roller using earth pressure cells(EPCs)is *** field trials were undertaken;the first trial used three EPCs placed at varying depths between 0.5 m and 1.5 m with towing speeds of 9-12 km/*** second used three EPCs placed at a uniform depth of 0.8 m,with towing speeds of 5-15 km/*** findings from the two trials confirmed that towing speed influences the pressure imparted to the ground and hence compactive *** paper proposes that the energy imparted to the ground is best described in terms of work done,which is the sum of the change in both potential and kinetic *** practice of using either kinetic energy or gravitational potential energy should be avoided as neither can accurately quantify rolling dynamic compaction(RDC)when towing speed is varied.

关键词： Rolling dynamic compaction(RDC) Optimum towing speed Ground improvement

Human protamines and the developing spermatid: their structure, function, expression and relationshipwith male infertility

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Asian Journal of Andrology 2003年第4期5卷 315-324页

作者： Vincent w. Aoki Douglas t. Carrell Andrology and IVF Laboratories University of Utah School of Medicine Salt Lake City UT 84108 USAAndrology and IVF Laboratories University of Utah School of Medicine Salt Lake City UT 84108 USA

During spermiogenesis, the protamine proteins play an integral role in spermatid chromatin compaction. Recent research has focused on many facets of protamine biology, including protamine gene and protein structure/ f... 详细信息

tract>During spermiogenesis, the protamine proteins play an integral role in spermatid chromatin compaction. Recent research has focused on many facets of protamine biology, including protamine gene and protein structure/ function relationships, mechanisms of protamine expression regulation and involvement of the protamines in male fertility. In this paper, we review our current understanding of the structure and function of the protamine-1 (P1) and protamine-2 (P2) proteins and genes, the expression and regulation of these genes and the relationship between the protamines and male fertility. In addition, we offer a brief outlook on future investigation into protamine proteins.

关键词： protamines spermatids male infertility spermatid transition proteins

Progress of amino acid nutrition for diet protein reduction in poultry

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Journal of Animal Science and Biotechnology 2021年第3期12卷 819-827页

作者： M.t.Kidd C.w.Maynard G.J.Mullenix Center of Excellence for Poultry Science Division of AgricultureUniversity of Arkansas SystemFayettevilleAR 72701USA

there is growing interest among nutritionists in feeding reduced protein diets to broiler *** nearly a century of research has been conducted providing biochemical insights on the impact of reduced protein diets for broilers,practical limitation still *** present review was written to provide insights on further reducing dietary protein in *** construct this review,eighty-nine peer reviewed manuscripts in the area of amino acid nutrition in poultry were ***,nutritional research areas of low protein diets,threonine,glycine,valine,isoleucine,leucine,phenylalanine,histidine,and glutamine have been assessed and combined in this text,thus providing concepts into reduced protein diets for *** addition,linkages between the cited work and least cost formation ingredient and nutrient matrix considerations are *** conclusion,practical applications in feeding reduced protein diets to broilers are advancing,but more work is warranted.

关键词： Amino acid Broiler chicken Glutamine Histidine Low protein threonine Valine

High-speed high-resolution laser diode-based photoacoustic microscopy for in vivo microvasculature imaging

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Visual Computing for Industry,Biomedicine,and Art 2021年第1期4卷 1-6页

作者： Xiufeng Li Victor t C tsang Lei Kang Yan Zhang terence t w wong translational and Advanced Bioimaging Laboratory Department of Chemical and Biological EngineeringHong Kong University of Science and TechnologyHong KongChina

Laser diodes(LDs)have been considered as cost-effective and compact excitation sources to overcome the requirement of costly and bulky pulsed laser sources that are commonly used in photoacoustic microscopy(PAM).However,the spatial resolution and/or imaging speed of previously reported LD-based PAM systems have not been optimized *** this paper,we developed a high-speed and high-resolution LD-based PAM system using a continuous wave LD,operating at a pulsed mode,with a repetition rate of 30 kHz,as an excitation source.A hybrid scanning mechanism that synchronizes a one-dimensional galvanometer mirror and a two-dimensional motorized stage is applied to achieve a fast imaging capability without signal averaging due to the high signal-to-noise *** optimizing the optical system,a high lateral resolution of 4.8μm has been *** vivo microvasculature imaging of a mouse ear has been demonstrated to show the high performance of our LD-based PAM system.

关键词： Photoacoustic microscopy Laser diode In vivo imaging Microvasculature imaging

Partial melting and re-solidification in partially melted zone during gas tungsten arc welding of AZ91 cast alloy

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中国有色金属学会会刊：英文版 2007年第A1期17卷 342-346页

作者： t. P. ZHU Z. w. CHEN w. GAO Department of Chemical and Materials Engineering University of Auckland NZ Department of Mechanical and Production Engineering Auckland University of Technology New Zealand

During the welding of AZ91 cast alloy,the presence of eutectic β-Mg17Al12 phase results in constitutional liquation in the original interdendritic regions and in the formation of a partially melted zone(PMZ). In this study,gas tungsten arc welding(GtAw) and partial melting(simulated using furnace,salt bath and Gleeble) experiments were conducted. the results show that practically there would not be a critical heating rate during the welding to prevent constitutional liquation. the gradual change of the re-solidification microstructure within PMZ from base metal side to weld metal side was characterized. A sharp transition from base metal to PMZ has been observed. It is found that the original partially divorced eutectic has become a more regular eutectic in most of the PMZ,although close to the fusion boundary the re-solidified eutectic is again a more divorced one. Proceeding the eutectic re-solidification,α-Mg re-solidified with a cellular growth resulting in a serrated interface. the morphological change affected by the peak temperature and cooling rate will be presented and explained.

关键词：镁合金凝固技术金属材料制造方法

Dietary branched-chain amino acid assessment in broilers from 22 to 35 days of age

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Journal of Animal Science and Biotechnology 2021年第2期12卷 755-762页

作者： M.t.Kidd F.Poernama t.wibowo C.w.Maynard S.Y.Liu Center of Excellence for Poultry Science Division of AgricultureUniversity of Arkansas SystemFayettevilleAR 72701USA Pt JAPFA Comfeed Indonesia tbk Jakarta 12810Indonesia School of Life and Environmental Sciences Faculty of ScienceThe University of SydneyBrownlow HillSydneyNSW 2570Australia

Background:Valine and isoleucine are similar in chemical structure and their limitation in broiler chicken *** evaluate their limitation and interactive effects,multivariate assessment nutrition studies for the branched-chain amino acids(BCAA)are needed.A three level(−1,0,+1),three-factor Box-Behnken design study was conducted to assess dietary BCAA ratios to lysine of 65,75,and 85 for valine,58,66,and 74 for isoleucine,and 110,130,and 150 for leucine in male and female Lohman Indian River broilers from 22 to 35 d of ***:Live performance of male broilers was not affected by BCAA ***,male broilers fed increasing isoleucine had improved(P=0.07)carcass yield as leucine and valine were *** broilers had improved body weight gain(P=0.05)and feed conversion(P=0.003)when leucine and isoleucine were at their lowest levels,independent of valine,but increasing leucine impaired live performance and warranted concomitant increases in isoleucine to restore *** dietary isoleucine and valine in female broilers increased breast meat yield(P=0.05),but increasing leucine tended to diminish the ***:the female Lohman Indian River broiler is more sensitive to BCAA diet manipulation than ***,as dietary leucine is increased in female broilers,dietary isoleucine increases were needed to offset the negative *** increases in dietary valine and isoleucine improved breast meat yield in female broilers,but only when birds were fed the lowest dietary leucine.

关键词： Broiler Crude protein Isoleucine Leucine Response surface Valine

Further numerical investigation on concrete dynamic behaviors with considering stress non-equilibrium in SHPB test based on the waveform features

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Acta Mechanica Sinica 2020年第4期36卷 873-886页

作者： t.H.Lv X.w.Chen Y.J.Deng G.Chen State Key Laboratory of Explosion Science and technology Beijing Institute of TechnologyBeijing 100081China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province Southwest University of Science and TechnologyMianyang 621000China Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621999China

In this study,with the meso-scale model reliably validated in our previous work(Construction and Building Materials,2018),the waveform features of plain concrete under various loading conditions and especially with considering stress non-equilibrium are reliably reproduced and *** with waveform features,the violation indicator of the specimen stress equilibrium in the split Hopkinson pressure bar test is identified for concrete-like damage softening *** concrete material behaviors for stress non-equilibrium are further analyzed,*** dynamic increase factor(DIF)and damage development,*** conception of“damage failure volume”is introduced,and a new method of defining the development of concrete dynamic damage is given in the nimierical ***’s more,the“compression wave”and“double peak”phenomena observed in the experiment are further interpreted based on the means of numerical *** features how to reflect the concrete material properties is also *** results show that,the disappearance of the“double peak” phenomenon of reflection curve under high strain rate can be regarded as the indicator of the violation of stress *** the violation of the stress equilibrium,the relevant DIFs of the concrete specimen will not change ***,the concrete specimen will turn into structural response from material *** conception of“damage failure volume”can well explain the generation of the“double peak”phenomenon of the reflection *** “compression wave” phenomenon of reflection curve under lower strain rates is derived from the unloading expansion recovery of the concrete ***,under the same loading condition,the amplitude of the first peak of the reflection curve can be used as the evaluation standard of the bonding quality between mortar and aggregates.

关键词： Concrete material Split Hopkinson pressure bar test Numerical investigation waveform feature Stress non-equilibrium Damage failure volume

Effects of weaving Laser on weld Microstructure and Crack for Al 6k21-t4 Alloy

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Journal of Materials Science & technology 2011年第1期27卷 93-96页

作者： B.H.Kim N.H.Kang w.t.Oh C.H.Kim J.H.Kim Y.S.Kim Y.H.Park Department of Materials Science and Engineering Pusan National UniversitySan30Jangjeon-dongGeumjeong-guBusan 609-735Korea Department of Materials and Components Engineering Dong-Eui UniversityBusan 614-714Korea Advanced Joining technology team KITECH7-47Songdo-dongYeonsu-guIncheon 406-840Korea Division for Dongnam Area technology Service KITECHJisa-dongGanseo-guBusan 618-230Korea

For Al 6k21-t4 overlap weld joint,the shear-tensile strength by using the weaving laser was improved as compared to the case of linear *** the specimen of low strength,the porosity was distributed continuously along the intersection between the plates and fusion ***,for the optimized welding condition,large oval-shaped porosities were located only in the advancing track of the concave ***,the continuity of cracks and porosities played a key role to determine the ***,the weaving width was also the important parameter to control the ***,the concave part had more significant hot and cold cracking in the weld and heat-affected zone（HAZ）,respectively,than the convex part.

关键词： weaving laser weld microstructure Void Al alloy

Design of a variable frequency comb reflectometer system for the ASDEX Upgrade tokamak

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Plasma Science and technology 2020年第6期22卷 8-14页

作者： t HAPPEL w KASPAREK P HENNEQUIN K HÖFLER C HONORÉ the ASDEX Upgrade team Max-Planck-Institut für Plasmaphysik Boltzmannstr.285748 GarchingGermany IGVP Universität StuttgartPfaffenwaldring 3170569 StuttgartGermany Laboratoire de Physique des Plasmas CNRSÉcole PolytechniqueSorbonne UniversitéF-91120 PalaiseauFrance Physik-Department E28 Technische Universität MünchenJames-Franck-Str.185748 GarchingGermany 不详

Comb reflectometers offer the advantage of measuring several radial positions in plasma *** allows for the investigation of fast timescales during L-H transitions,I-phases,I-mode bursts,transients during heat wave propagation,etc.A drawback of many present-day systems is that they use a fixed frequency difference between the probing ***,although the central probing frequency can be varied,the probing frequency difference is usually *** new design presented in this work uses an advanced microwave generation and detection scheme,which allows for arbitrary probing frequencies and probing frequency separations.

关键词： reflectometry microwaves plasma diagnostic reflectometer turbulence