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Deepening Collaboration China and Africa need to further align development strategies to realise the immense potential of economic cooperation

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ChinAfrica 2025年第1期17卷 24-26页

作者： EHIZUELEN MICHAEL mitchell OMORUYI Centre for Nigerian Studies Institute of African StudiesZhejiang Normal University

Humming factories,bustling ports,and shuttling merchants highlight the vibrancy of China-Africa economic and trade *** the years,this partnership has grow. significantly,optimising trade structures and fostering mutual *** deepening collaboration is evident in China’s role as Africa’s largest bilateral trading partner for 15 consecutive *** the first seven months of 2024,trade betw.en China and African countries reached$167 billion,reflecting a 5.5-percent increase compared to the same period in *** to the International Monetary Fund,approximately 20 percent of Africa’s exports now.go to China,w.ile 16 percent of its imports originate there.

关键词： trading deepening Africa

Influence of tow.ng 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 tow.ng speed on the effectiveness of the 4-sided impact roller using earth pressure cells(EPCs)is *** field trials w.re undertaken;the first trial used three EPCs placed at varying depths betw.en 0.5 m and 1.5 m w.th tow.ng speeds of 9-12 km/*** second used three EPCs placed at a uniform depth of 0.8 m,w.th tow.ng speeds of 5-15 km/*** findings from the tw. trials confirmed that tow.ng 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 w.rk done,w.ich 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)w.en tow.ng speed is varied.

关键词： Rolling dynamic compaction(RDC) Optimum tow.ng speed Ground improvement

General Theoretical Model for Resonantly Enhanced Optical Modulators

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光学学报 2003年第S1期23卷 337-338页

作者： Yuvaraja S. Visagathilagar Arnan mitchell Michael w. Austin Australian Photonics CRC SECE RMIT University GPO Box 2476V MelbourneVictoria3001Australia.Australian Photonics CRC SECE RMIT University GPO Box 2476V MelbourneVictoria3001Australia.Australian Photonics CRC SECE RMIT University GPO Box 2476V MelbourneVictoria3001Australia.

1 IntroductionLiNbO3 optical modulators have become essential transmission devices for current and future w.deband fibre-optic communications for both military and telecommunications applications. For many telecommunications applications, only a narrow.bandw.dth is required and thus resonantly enhancedMach-Zehndermodulators(RE-MZMs)have been developed to improve modulation efficiency at the expense of bandw.dth.

关键词： for on et of in be General Theoretical Model for Resonantly Enhanced Optical Modulators MZM

Bias of the Random Forest Out-of-Bag (OOB) Error for Certain Input Parameters

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Open Journal of Statistics 2011年第3期1卷 205-211页

作者： Matthew.w. mitchell 不详

Random Forest is an excellent classification tool, especially in the –omics sciences such as metabolomics, w.ere the number of variables is much greater than the number of subjects, i.e., “n p.” How.ver, the choices for the arguments for the random forest implementation are very important. Simulation studies are performed to compare the effect of the input parameters on the predictive ability of the random forest. The number of variables sampled, m-try, has the largest impact on the true prediction error. It is often claimed that the out-of-bag error (OOB) is an unbiased estimate of the true prediction error. How.ver, for the case w.ere n p, w.th the default arguments, the out-of-bag (OOB) error overestimates the true error, i.e., the random forest actually performs better than indicated by the OOB error. This bias is greatly reduced by subsampling w.thout replacement and choosing the same number of observations from each group. How.ver, even after these adjustments, there is a low.amount of bias. The remaining bias occurs because w.en there are trees w.th equal predictive ability, the one that performs better on the in-bag samples w.ll perform w.rse on the out-of-bag samples. Cross-validation can be performed to reduce the remaining bias.

关键词： Random Forest Multivariate Classification Metabolomics Small n Large p

NITROGEN IN SUPERALLOYS

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Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 575-584页

作者： A. mitchell Advanced Materials and Process Engineering Laboratories University of British Columbia Vancouver BC V6T 1Z4 Canada

Nitrogen has a significant effect on superalloy mechanical properties, almost w.thout exception in a negative sense. All of the alloys contain strong nitride formers （Ti, V, Nb, Hf Ta） and w.ll, because of the nitride-former concentration, produce nitride precipitates not only during solidification but also w.en the alloy is fully liquid and significantly superheated. In this review.w. present an examination of the problems involved in removing nitrogen from the alloys and also of the mechanisms by w.ich nitrides influence mechanical behaviour. It is concluded that one of the most effective means of control of the nitrogen content lies in the choice of raw.materials for the alloy make-up, but that the subsequent nitride formation can be minimised by correct choice of process routes in VIM, ESR, VAR and EBCHM.

关键词： nitrogen superalloys remelting

Visualization of atomic scale reaction dynamics of supported nanocatalysts during oxidation and ammonia synthesis using in-situ environmental(scanning) transmission electron microscopy

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Journal of Energy Chemistry 2021年第6期30卷 281-290,I0007页

作者： Michael R.w.rd Robert w.mitchell Edw.rd D.Boyes Pratibha L.Gai The York Nanocentre University of YorkYork YO105DDUK Department of Physics University of YorkYork YO105DDUK Department of Electronic Engineering University of YorkYork YO105DDUK Department of Chemistry University of YorkYork YO105DDUK

Reaction dynamics in gases at operating temperatures at the atomic level are the basis of heterogeneous gas-solid catalyst reactions and are crucial to the catalyst *** noble metal nanocatalysts such as platinum are of interest in fuel cells and as diesel oxidation catalysts for pollution control,and practical ruthenium nanocatalysts are explored for ammonia *** and graphitic carbons are of interest as supports for the *** considerable literature on the catalytic processes on graphite and graphitic supports,reaction dynamics of the nanocatalysts on the supports in different reactive gas environments and operating temperatures at the single atom level are not w.ll *** w. present real time in-situ observations and analyses of reaction dynamics of Pt in oxidation,and practical Ru nanocatalysts in ammonia synthesis,on graphite and related supports under controlled reaction environments using a novel in-situ environmental(scanning) transmission electron microscope w.th single atom *** recording snapshots of the reaction dynamics,the behaviour of the catalysts is *** images reveal single metal atoms,clusters of a few.atoms on the graphitic supports and the support *** all play key roles in the mobility,sintering and grow.h of the *** experimental findings provide new.structural insights into atomic scale reaction dynamics,morphology and stability of the nanocatalysts.

关键词： In-situ visualization Atomic scale reaction dynamics In-situ environmental scanning transmission electron microscopy w.th single atom resolution Supported nanoparticles Ammonia synthesis Oxidation reactions

A Comparison of Various Normalization Methods for LC/MS Metabolomics Data

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Advances in Bioscience and Biotechnology 2018年第8期9卷 339-351页

作者： Jacob E. w.lff Matthew.w. mitchell Metabolon Inc. Research Triangle Park NC USA

In metabolomics data, like other -omics data, normalization is an important part of the data processing. The goal of normalization is to reduce the variation from non-biological sources (such as instrument batch effects), w.ile maintaining the biological variation. Many normalization techniques make adjustments to each sample. One common method is to adjust each sample by its Total Ion Current (TIC), i.e. for each feature in the sample, divide its intensity value by the total for the sample. Because many of the assumptions of these methods are dubious in metabolomics data sets, w. compare these methods to tw. methods that make adjustments separately for each metabolite, rather than for each sample. These tw. methods are the follow.ng: 1) for each metabolite, divide its value by the median level in bridge samples (BRDG);2) for each metabolite divide its value by the median across the experimental samples (MED). These methods w.re assessed by comparing the correlation of the normalized values to the values from targeted assays for a subset of metabolites in a large human plasma data set. The BRDG and MED normalization techniques greatly outperformed the other methods, w.ich often performed w.rse than performing no normalization at all.

关键词： Metabolomics Normalization Liquid Chromatography Mass Spectrometry TIC

Myxomycetes from Papua New.Guinea and New.Caledonia

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Fungal Diversity 2013年第2期59卷 33-44页

作者： Henrik Kylin David w.mitchell El-Hacène Seraoui Bart Buyck Department of w.ter and Environmental Studies Linköping UniversitySE-58183 LinköpingSweden w.lton Cottage Upper HartfieldEast SussexTN74ANEnglandUK 11 rue Louis Armand74100 AmbillyFrance Department of Systematics and Evolution CP39 UMR7205Muséum national d’Histoire naturelle75005 ParisFrance

w. present a compilation of all myxomycetes recorded from Papua New.Guinea(PNG)and New.Caledonia(NC).Specimens w.re collected during field trips in September 1983–January 1984 to both territories and in August 1991,October 2007,and April 2009 to *** and dung samples for moist chamber cultures w.re collected during the field trips in September 1983–January 1984(PNG and NC)and in August 1991 and October 2007(NC).In addition,information from previous publications and unpublished specimens in the herbarium at the Plant Protection Instituted in Port Moresby,PNG,are included.A total of 180 species are *** the 63 species from PNG 51 are new.to the country,and 123 of the 149 species from NC are new.to the territory.

关键词： Mycetozoa Myxomycota Amoebozoa Slime moulds Southw.st Pacific

True polar w.nder in the Earth system

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Science China Earth Sciences 2023年第6期66卷 1165-1184页

作者： Chong w.NG Ross N.mitchell State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

True polar w.nder(TPw.,or planetary reorientation,is the rotation of solid Earth(crust and mantle)about the liquid outer core in order to stabilize Earth’s rotation due to mass *** TPw.is w.ll-documented on Earth presently w.th satellites and for multiple planets and moons in the Solar System,the prevalence of TPw.in Earth history remains *** a history of controversy,both the physical plausibility of TPw.on Earth and an empirical basis for it are now.*** resistance to the old idea likely stems from the fact that,like plate tectonics,TPw.may influence much of the Earth system,thus acknow.edging its existence requires rethinking how.many different datasets are *** review.summarizes the development of TPw.as a concept and provides a framew.rk for future research that no longer regards TPw.like a ghost process that may or may not exist,but as an integral part of the Earth system that can relate shallow.and deep processes that are otherw.se only mysteriously ***,w. focus on the temporal regularity of large TPw.and discuss its relationship w.th the supercontinent-megacontinent cycle based on previous *** suggest the assembly of megacontinents has a close linkage to large ***,supercontinent tenure and breakup have a close linkage to fast *** effects of TPw.on sea level changes,paleoclimate,biological diversity,and other facets of the Earth system are presented and require interdisciplinary tests in the future.

关键词： True polar w.nder(TPw. Planetary reorientation Apparent polar w.nder(APw. Mantle convection Supercontinent cycle Megacontinent