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Laser cut hole matrices in novel armour plate steel for appliqué battlefield vehicle protection

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Defence Technology（防务技术） 2016年第5期12卷 351-359页

作者： daniel j. THOMAS Engineering Manufacturing Centre College of Engineering Swansea University Swansea UK

During this research, experimental rolled homogeneous armour steel was cast, annealed and laser cut to form an appliqué plate. This Martensitic–Bainitic microstructure steel grade was used to test a novel means of engineering lightweight armour. It was determined that a laser cutting speed of 1200 mm/min produced optimum hole formations with limited distortion. The array of holes acts as a double-edged solution, in that they provide weight saving of 45%, providing a protective advantage and increasing the surface area. Data collected were used to generate laser cut-edge hole proj.ctions in order to identify the optimum cutting speed, edge condition, cost and deformation performance. These parameters resulted in the generation of a surface, with less stress raising features. This can result in a distribution of stress across the wider surface. Provided that appropriate process parameters are used to generate laser cut edges, then the hardness properties of the surface can be controlled. This is due to compressive residual stresses produced in the near edge region as a result of metallurgical transformations. This way the traverse cutting speed parameter can be adj.sted to alter critical surface characteristics and microstructural properties in close proximity to the cut-edge. A relationship was identified between the width of the laser HAZ and the hardness of the cut edge. It is the thickness of the HAZ that is affected by the laser process parameters which can be manipulated with adj.sting the traverse cutting speed.

关键词： Armour steels Defence systems Steel processing Armour engineering

Design of synthetic materials for intracellular delivery of RNAs： From siRNA-mediated gene silencing to CRISPR/Cas gene editing

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Nano Research 2018年第10期11卷 5310-5337页

作者： j.son B. Miller daniel j. Siegwart Simmons Comprehensive Cancer Center University of Texas Southwestern Medical Center Dallas TX 75390 USA Department of Biochemistry University of Texas Southwestern Medical Center Dallas TX 75390 USA

Ribonucleic acids （RNAs） possess great therapeutic potential and can be used to treat a variety of diseases. The unique biophysical properties of RNAs, such as high molecular weight, negative charge, hydrophilicity, low stability, and potential immunogenicity, require chemical modification and development of carriers to enable intracellular delivery of RNAs for clinical use. A variety of nanornaterials have been developed for the effective in vivo delivery of short/ small RNAs, messenger RNAs, and RNAs required for gene editing technologies including clustered regularly interspaced palindromic repeat （CRISPR）/Cas. This review outlines the challenges of delivering RNA therapeutics, explores the chemical synthesis of RNA modifications and carriers, and describes the efforts to design nanomaterials that can be used for a variety of clinical indications.

关键词： nucleic acid therapeutics nanoparticles synthetic nanomaterials RNA interference (RNAi) messenger RNA (mRNA) clustered regularly inter-spaced palindromic repeat(CRISPR)/Cas

Periodic Orbits in Rotating Second Degree and Order Gravity Fields

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Chinese j.urnal of Astronomy and Astrophysics 2008年第1期8卷 108-118页

作者： Wei-Duo Hu daniel j. Scheeres School of Astronautics BeiHang University Beijing 100083 Department of Aerospace Engineering The University of Michigan Ann Arbor MI48109 USA

Periodic orbits in an arbitrary 2nd degree and order uniformly rotating gravity field are studied. We investigate the four equilibrium points in this gravity field. We see that close relation exists between the stability of these equilibria and the existence and stability of their nearby periodic orbits. We check the periodic orbits with non-zero periods. In our searching procedure for these periodic orbits, we remove the two unity eigenvalues from the state transition matrix to find a robust, non-singular linear map to solve for the periodic orbits. The algorithm converges well, especially for stable periodic orbits. Using the searching procedure, which is relatively automatic, we find five basic families of periodic orbits in the rotating second degree and order gravity field for planar motion, and discuss their existence and stability at different central body rotation rates.

关键词： celestial / orbital mechanics - asteroid - periodic orbit - resonance

RULEMAKING POSSIBILITIES： EFFORTS OF THE UNITED STATES j.DICIAL CONFERENCE ADVISORY COMMITTEE ON EVIDENCE RULES TO ADDRESS THE CHALLENGES TO FORENSIC EXPERT TESTIMONY

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Frontiers of Law in China-Selected Publications from Chinese Universities 2018年第1期13卷 34-42页

作者： daniel j. Capra School of Law University of California Berkeley USA Reed Professor School of Law Fordharn University New York 10023 USA

This piece is an echo to one of the main subj.cts of the Sixth International Conference on Evidence Law and Forensic Science which is to determine what evidentiary reforms are necessary for regulating forensic expert testimony, and how those reforms might be implemented. In United States, the predominant way of evidentiary reform is through rulemaking. As the Reporter of j.dicial Conference Advisory Committee on the Federal Rules of Evidence since 1996, the author, with a pragmatic spirit throughout the article, examines such an effort at the federal level of U.S. in six parts （levels）, starting from the most general, abstract level till fmishing with the most detailed and substantive points. Part I begins with a brief introduction of the hierarchies of evidentiary rulemaking authorities at the federal level of the United States, various interested groups and their interesting interactions in the rulemaking process. The author then shifts to the general topic of writing rules with a specific focus on the level of detail that is to be provided in doing so; Part II further narrows down the scrutiny into writing a rule on forensic expert testimony with an emphasis on the necessity of making such a rule change to the current general standards of FRE; Part III directly addresses the challenges of drafting a rule on forensic evidence in FRE, including a comparation of various alternative drafting models; Part IV and Part V respectively discusses the Reporter＇s comments and the j.stice Department＇s concerns over the drafted rules; and Part VI briefly discusses the feasibility and effectiveness of a Best Practices Manual on forensic evidence in lieu of rulemaking.

关键词： forensics rulemaking reliability expert

Towards maximized utilization of iridium for the acidic oxygen evolution reaction

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Nano Research 2019年第9期12卷 2275-2280页

作者： Marc Ledendecker Simon Geiger Katharina Hengge j.ohyun Lim Serhiy Cherevko Andrea M. Mingers daniel Gohl Guilherme V. Fortunato daniel j.lalpoor Ferdi Schuth Christina Scheu Karl j. j. Mayrhofer Department of Interface Chemistry and Surface Engineering Nanoanalytics and Interfaces Max-Planck-Institut fur Eisenforschung GmbH40237 DusseldorfGermany Department of Heterogeneous Catalysis Max-Planck-Institut fur KohlenforschungKaiser- Wilhelm-Platz 145470 Mulheim an der RuhrGermany Helmholtz-Institute Erlangen-Nurnbergfar Renewable Energy (IEK-11) Forschungszentrum Jillich91058 ErlangenGermany Department of Chemical and Biological Engineering Friedrich-Alexander- Universitat Erlangen -Nurnberg91058 ErlangenGermany Institute of Chemistry Universidade Federal de Mato Grosso do SulAv. Senador Filin to Muller1555Campo GrandeMS 79074-460Brazil

The reduction in noble metal content for efficient oxygen evolution catalysis is a crucial aspect towards the large scale commercialisation of polymer electrolyte membrane *** catalytic stability and activity are inversely related,long service lifetime still demands large amounts of low-abundant and expensive *** this manuscript we elaborate on the concept of maximizing the utilisation of iridium for the oxygen evolution *** combining different tin oxide based support materials with liquid atomic layer deposition of iridium oxide,new possibilities are opened up to grow thin layers of iridium oxide with tuneable noble metal ***-situ,time-and potential-resolved dissolution experiments reveal how the stability of the substrate and the catalyst layer thickness directly affect the activity and stability of deposited iridium *** on our results,we elaborate on strategies how to obtain stable and active catalysts with maximized iridium utilisation for the oxygen evolution reaction and demonstrate how the activity and durability can be tailored *** results highlight the potential of utilizing thin noble metal films with earth abundant *** for future catalytic applications in the energy sector.

关键词： oxygen evolution reaction liquid atomic layer depositi on catalysis iridium core-shell nano particles

Avalonia,get bent!–Paleomagnetism from SW Iberia confirms the Greater Cantabrian Orocline

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Geoscience Frontiers 2021年第2期12卷 805-825页

作者： Bruno daniel Leite Mendes daniel Pastor-Galan Mark j.Dekkers Wout Krij.sman Paleomagnetic Laboratory Fort Hoofddij. Department of Earth SciencesUtrecht UniversityBudapestlaan 173584CDthe Netherlands Frontier Research Institute for Interdisciplinary Sciences Tohoku UniversityJapan Department Earth Science Tohoku UniversityJapan Center for North East Asia Studies Tohoku University980-857641 KawauchiAoba-kuSendaiMiyagiJapan

The amalgamation of Pangea formed the contorted Variscan-Alleghanian orogen,suturing Gondwana and Laurussia during the *** all swirls of this orogen,a double curve in Iberia stands out,the coupled Cantabrian Orocline and Central Iberian *** Cantabrian Orocline formed at ca.315–290 Ma subsequent to the Variscan *** formation mechanism of the Cantabrian Orocline is disputed,the most commonly proposed mechanisms include either(1)that south-westernmost Iberia would be an Avalonian(Laurussian)indenter or(2)that the stress field changed,buckling the *** contrast,the geometry and kinematics of the Central Iberian curve are largely *** some authors defend both curvatures are genetically linked,others support they are distinct and formed at different *** uncertainty adds an extra layer of complexity to our understanding of the final stages of Pangea’s *** solve these issues,we study the late Carboniferous–early Permian vertical-axis rotations of SW Iberia with *** results show up to 70counterclockwise vertical-axis rotations during late Carboniferous times,concurring with the anticipated kinematics if SW Iberia was part of the southern limb of the Cantabrian *** results do not allow the necessary penecontemporaneous clockwise rotations in Central Iberia to support a concomitant formation of both Cantabrian and Central Iberian *** coherent rotation of both Gondwanan and Avalonian pieces of SW Iberia discards the Laurussian indenter hypothesis as a formation mechanism of the Cantabrian Orocline and confirms the Greater Cantabrian Orocline *** Greater Cantabrian Orocline likely formed as a consequence of a change in the stress field during the late Carboniferous and extended beyond the Rheic Ocean suture affecting the margins of both Laurussia and Gondwana.

关键词： Pangea Variscan orogeny Greater Cantabrian Orocline Paleomagnetism Central Iberian curve

Network analysis to inform invasive species spread among lakes

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j.urnal of Oceanology and Limnology 2019年第3期37卷 1037-1041页

作者： ESCOBAR Luis E. ROMERO-ALVAREZ daniel LARKIN daniel j. PHELPS Nicholas B. D. Department of Fish and Wildlife Conservation Virginia TechBlacksburgVirginiaUSA Department of Ecology and Evolutionary Biology-Biodiversity Institute University of KansasLawrenceUSA Department of Fisheries Wildlifeand Conservation BiologyUniversity of MinnesotaSt.PaulMinnesotaUSA Minnesota Aquatic Invasive Species Research Center University of MinnesotaSt.PaulMinnesotaUSA

Often facilitated by human-mediated pathways,aquatic invasive species are a threat to the health and biodiversity of global *** present a novel approach incorporating survey data of watercraft movement in a social network analysis to reconstruct potential pathways of aquatic invasive species spread between *** an example,we use the green alga Nitellopsis obtusa,also known as starry stonewort,an aquatic invasive species affecting the Great Lakes region in the United States and *** movement of algal fragments via human-mediated pathways(i.e.,watercraft)has been hypothesized as the primary driver of starry stonewort *** used survey data collected at boat ramps during the 2013 and 2014 openwater seasons to describe the flow of watercraft from Lake Koronis,where *** was first detected in Minnesota,to other lakes in the *** results suggest that the risk of *** expansion is not highly constrained by geographic proximity and management efforts should consider highly connected *** human movement via network analysis may help to explain past and future routes of aquatic invasive species infestation between lakes and can improve evidence-based prevention and control efforts.

关键词： Nitellopsis obtusa starry stonewort lake network invasion

Optimal decentralized control of large scale systems

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Control Theory and Technology 2016年第4期14卷 287-313页

作者： Xiao Qi SHI daniel E. DAVISON Raymond KWONG Edward j. DAVISON Systems Control Group Department of Electrical and Computer Engineering University of Toronto Ontario Canada MSS 3G4 Department of Electrical and Computer Engineering University of Waterloo Ontario Canada N2L 3G1

This paper presents a new optimized decentralized controller design method for solving the tracking and disturbance rej.ction problems for large-scale linear time-invariant systems, using only low-order decentralized controllers. To illustrate the type of results which can be obtained using the new optimized decentralized control design method, the control of a large flexible space structure is studied and compared with the standard centralized LQR-observer controller. The order of the resultant decentralized controller is much smaller than that of the standard centralized LQR-observer controller. The proposed controller also has certain fail-safe properties and, in addition, it can be five orders of magnitude more robust than the standard LQR-observer controller based on their real stability radii. The new decentralized controller design method is applied to a large flexible space structure system with 5 inputs and 5 outputs and of order 24.

关键词： Decentralized control multivariable control PID control robustness optimization large-scale systems flexiblestructures

Multi-scale magnetic resonance measurements and validation of Discrete Element Model simulations

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Particuology 2011年第4期9卷 330-341页

作者： Christoph R. Müller daniel j. Holland j.mes R. Third Andrew j. Sederman j.hn S. Dennis Lynn F. Gladden Institute of Energy Technology Department of Mechanical and Process Engineering Department of Chemical Engineering and Biotechnology University of Cambridge

This short review describes the capabilities of magnetic resonance （MR） to image opaque single- and two-phase granular systems, such as rotating cylinders and gas-fluidized beds operated in different fluidization regimes. The unique capability of MR to not only image the solids＇ distribution （voidage） but also the velocity of the particulate phase is clearly shown. It is demonstrated that MR can provide measurements over different length and time scales. With the MR equipment used for the studies summarized here, temporal and spatial scales range from sub-millisecond to hours and from a few hundred micrometres to a few centimetres, respectively. Besides providing crucial data required for an improved understanding of the underlying physics of granular flows, multi-scale MR measurements were also used to validate numerical simulations of granular systems. It is shown that predictions of time-averaged properties, such as voidage and velocity of the particulate phase, made using the Discrete Element Model agree very well with MR measurements.

关键词： Discrete Element Modelling Magnetic resonance imaging MultiscaleGas-fluidized beds Rotating cylinders