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On Turbulent Contribution to Frictional Drag in Wall-Bounded Turbulent Flow

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Chinese Physics Letters 2006年第5期23卷 1226-1229页

作者：李凤臣 KAWAGUCHI Yasuo HISHIDA Koichi OSHIMA marie School of Energy Science and Engineering Harbin Institute of Technology Harbin 150001 Institute of Industrial Science The University of Tokyo Komaba 4-6-1 Meguro-ku Tokyo 153-8505 Japan Department of Mechanical Engineering Tokyo University of Science Yamazaki 2641 Noda Chiba 278-8510 Japan Department of System Design Engineering Keio University Yokohama 223-8522 Japan

We propose a simple model for turbulent contribution to the frictional drag in a wall-bounded turbulent flow based on the characteristic parameters of turbulent bursting events, it is verified on water and drag-reducing surfactant solution flows investigated by particle image velocimetry in experiments. It is obtained that the turbulent contribution to the skin friction factor is linearly proportional to the product of the spatial frequency and strength of turbulent bursts originated from the wall.

关键词： DIRECT NUMERICAL-SIMULATION PARTICLE IMAGE VELOCIMETRY LOW-REYNOLDS-NUMBER CHANNEL FLOW LAYER STRESS EXCHANGE PACKETS MOTIONS GROWTH

Monomer-activated Copolymerization of Ethylene Oxide and Epichlorohydrin: In Situ Kinetics Evidences Tapered Block Copolymer Formation

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Chinese Journal of Polymer Science 2019年第9期37卷 912-918页

作者： Ann-Kathrin Danner Daniel Leibig Lea-marie Vogt Holger Frey Institute of Organic Chemistry Johannes Gutenberg- Universitat Mainz Duesbergweg 10-14 55128 Mainz Germany Graduate School Materials Science in Mainz Staudinger Weg 9 55128 Mainz Germany

The monomer-activated anionic ring-opening copolymerization (AROP) of ethylene oxide (EO) and epichlorohydrin (ECH) using tetraoctylammonium bromide as an initiator and triisobutylaluminum (i-Bu3Al) as an activator was studied. The properties of the copolymers as well as the microstructure have been analyzed in detail via an in situ NMR kinetics study. The statistical copolymers exhibited molecular weights ranging from 2350 g·mol^-1 to 38000 g·mol^-1 (measured by SEC, PEG-standards) and moderate dispersities of 1.27-1.44. The thermal property tests revealed both a glass transition and melting for all copolymers, supporting a block-like nature. Applying in situ NMR kinetic measurements, the reactivity ratios of EO and ECH were determined to be strongly disparate, i.e., rEo = 9.2 and rECH = 0.10. This shows that the simple one-pot statistical anionic copolymerization of EO and ECH via the monomer-activated AROP resulted in the formation of strongly tapered, block-like structures. Furthermore, post-polymerization functionalization of the reactive chloromethyl groups by nucleophilic displacement was investigated for the copolymers. Copolymerization of EO and ECH offers a broad platform for further functionalization and therefore the possibility to prepare a variety of multifunctional PEGs.

关键词： Epichlorohydrin Polymerization Ring-opening Copolymerization Reactivity ratios Epoxide

Predictive approach of heterogeneous catalysis

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National Science Review 2018年第5期5卷 633-635页

作者： Jean-marie Basset Jérémie D.A.Pelletier King Abdullah University of Science and Technology

‘Predictive catalysis’ or ‘catalysis by design’ has recently advanced heterogeneous catalysis by using the conceptual tool of surface fragments [1] such as ‘surface organometallic fragments’(SOMF)or ‘surface coordination fragments’(SCF) to achieve and understand a presumed catalytic cycle (see Fig. 1).One or several fragments of the molecule

关键词： SCF CR CO EXAFS

Synthesis and properties of SrFe_(12)O_(19) obtained by solid waste recycling of oily cold rolling mill sludge

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 642-648页

作者： Bo Liu Shen-gen Zhang Britt-marie Steenari Christian Ekberg Institute for Advanced Materials and Technology University of Science and Technology Beijing Nuclear Chemistry and Industrial Material Recycling Department of Chemistry and Chemical Engineering Chalmers University of Technology

The aim of this study was to develop a new approach for the preparation of environmentally friendly, high-value products from oily cold rolling mill(CRM) sludge. Utilizing oily CRM sludge as a source of iron, strontium hexaferrite(SrFe_(12)O_(19)) powders were prepared by multi-step processes involving acid leaching, chemical conversion treatment, and synthesis by a citrate precursor. The influences of citric acid dosage and the pH of the sol system on the formation, crystallite size, and magnetic properties of the obtained SrFe_(12)O_(19) powders were investigated. High saturation magnetization(74.8 mA·m^2·g^(–1)) and intrinsic coercivities(614.46 mT) were achieved for pH 7.0 of the sol system, for which the molar ratio of citric acid dosage to the total dosage of Fe^(3+) and Sr^(2+) was 1.5. This study presents a new approach to utilizing oily CRM sludge, and even refractory iron-containing solid waste.

关键词： strontium ferrite oily cold rolling mill sludge magnetic properties citrate precursor method recycling

Combination of Instrumented Nanoindentation and Scanning Probe Microscopy for Adequate Mechanical Surface Testing

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Journal of Materials Science & Technology 2009年第1期25卷 63-68页

作者： Enrico Tam Mikhail Petrzhik Dmitry Shtansky marie-Paule Delplancke-Ogletree Université Libre de Bruxelles Moscow State Institute of Steel and Alloys

The elastic indentation modulus and hardness of standard bulk materials and advanced thin films were determined by using the nanoindentation technique followed by the Oliver- Pharr post-treatment. After measurements with different loading/unloading schemes on chemically polished bulk titanium a substantial decrease of both modulus and hardness vs an increasing loading time was found. Then, hard nanostructured TiBN and TiCrBN thin films deposited by magnetron sputtering （using multiphase targets） on substrates of high roughness （sintered hard metal） and low roughness （silicon） were studied. Experimental modulus and hardness characterized by using two different nanoindenter tools were within the limits of standard deviation. However, a strong effect of roughness on the spread of the experimental values was observed and it was found that hardness and elastic indentation modulus obeyed a Gaussian distribution. The experimental data were discussed together with scanning probe microscopy （SPM） images of typical imprints taken after the nanoindentation tests and the local topographyls strong correlation with the results of nanoindentation was described.

关键词： Nanoindentation Thin films Coatings Scanning probe microscopy

Marine Oxygen Isotope Stage(MIS)-6 Glacial Advances on the Tibetan Plateau More Extensive than during MIS-2 due to More Abundant Precipitation

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Acta Geologica Sinica(English Edition) 2022年第5期96卷 1484-1494页

作者： marie-Luce CHEVALIER WANG Shiguang Anne REPLUMAZ LI Haibing Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Institute of GeologyCAGSBeijing 100037China Jiangsu Donghai Crustal Activity in Deep Holes of the Continental Scientific Drilling National Observation and Research Station LianyungangJiangsu 222300China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China National Institute of Natural Hazards MEMCBeijing 100037China ISTerre UniversitéGrenoble AlpesCNRSGrenoble 38610France

Numerous studies dated glacial deposits within the Himalayan-Tibetan *** most focus on young deposits,i.e.,younger than the Last Glacial Maximum(LGM or Marine oxygen Isotope Stage(MIS)-2,~20 ka),older moraines such as those from MIS-6(~130–191 ka)are much harder to date and interpret due to the less well-preserved nature of their surfaces and boulders,as well as their scattered and continuous age distribution due to long-lived erosion since ***,we dated with~(10)Be,two imbricated moraines near Yadong in southern Tibet,as MIS-2 and 6,showing that the most extensive,smooth surfaces were abandoned during *** published data from 54 MIS-6 moraines on the Tibetan Plateau reveals that they exist in most regions,dry or *** are particularly well-preserved(sharp crests)in eastern and northern Tibet,while in southern and central Tibet,their crests are rounded to *** both MIS-2 and 6 were equally cold,and because MIS-6 moraines are much more extensive than those from the LGM,we conclude that MIS-6 glacial advances were controlled by more abundant precipitation than during *** would be consistent with the peak in Asian monsoon during MIS-6,revealed by sediments from the South China Sea.

关键词： Yadong rift southern Tibet cosmogenic isotopes Quaternary paleo-precipitation moraine morphology Indian monsoon

Electrospinning of supramolecular polymer complexes

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Science China Chemistry 2013年第1期56卷 24-32页

作者： RICHARD-LACROIX marie PELLERIN Christian Département de Chimie and Centre for Self-assembled Chemical Structures Université de MontréalMontréalQC H3C 3J7Canada

Supramolecular polymer complexes with small molecules are self-assembled through non-covalent interactions and have been proposed for a wide variety of applications in materials science and *** research group has recently shown the possibility of forming highly ordered nanofibers of supramolecular complexes in their thermodynamically stable state using the electrospinning *** ultrafast solvent evaporation rate of electrospinning made possible the in-depth characterization of complexes that had never been prepared in their pure state before because of kinetic issues associated with their formation by conventional *** improved understanding of the formation mechanism allowed us to extend the concept to other techniques featuring a fast solvent evaporation rate,such as electrospray and *** this article,we review our most significant contributions in this research field.

关键词： polymer complexes electrospinning poly(ethylene oxide) urea thiourea

Vehicle OHT Dispatching Performance Analysis of an AM HS in 300 mm Semiconductor FABs

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Journal of Donghua University(English Edition) 2012年第3期29卷 209-214页

作者：周炳海 ANAR Jean-marie 郑雯 School of Mechanical Engineering Tongji University

To improve the performance of an automated material handling system (AMHS) in 300 mm semiconductor fabrication plants (FABs), an overhead-hoist-transport (OHT) vehicle dispatching problem was described for semiconductor FABs. An original wafer lot dispatching policy was proposed. To minimize costs due to transportation logic, a dispatching rule based on an adapted Hungarian algorithm was presented, and six factors were considered. In addition to the recurring parameters, two original parameters of the vehicles utilization and wafer lot priority were considered to evaluate system performance. To obtain a balanced efficiency regarding the FAB output factors, simulation and sensitive analysis were used to find the best weight parameters of the cost matrix. In particular, a high rate of priority wafer lots (greater than 20%) and vehicles utilization (greater than 75%) are obtained without penalizing the efficiency of the FABs. The results indicate that the proposed dispatching policy is valid and practical.

关键词： overhead-hoist-transport (OHT) Hungarian algorithm cost matrix disoatching rule

Hairpin Priming Is Better Suited than In Vitro Polyadenylation to Generate cDNA for Plant miRNA qPCR

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Molecular Plant 2013年第1期6卷 229-231页

作者： Sajag Adhikari marie Turner Senthil Subramanian Department of Plant Science South Dakota State University Brookings SD 57007 USA

Dear Editor, microRNAs （miRNAs） are short non-coding RNAs that play crucial roles in plant development and responses to biotic and abiotic stresses, miRNA biogenesis starts with the tran- scription of a hairpin-forming pri-miRNA that is sequentially cleaved yielding a duplex RNA molecule consisting of the mature miRNA （typically 21-22 nt in length） and miRNA＊. Typically, mature miRNAs are the active forms and are incor- porated into different RNA-induced silencing complexes that regulate gene expression by inhibition of translation or cleavage of complementary mRNAs （reviewed in Axtell et al., 2011）.

关键词： miRNAs 基因植物聚腺苷非生物胁迫酸化体外引发非编码RNA