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Fundamental principles of an effective reinforcing roof bolting strategy in horizontally layered roof strata and areas of potential improvement

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International Journal of Mining Science and Technology 2018年第1期28卷 67-77页

作者： Russell Frith Guy Reed martin McKinnon Mine Advice Pty Ltd New South Wales 2282Australia

It is arguable that the development of reinforcing roof bolting systems has largely stagnated in recent times, primarily due to the prevailing industry view that few, if any, further improvements can be made to what currently ***, this paper contends that reinforcing roof bolting systems can be further refined by considering both the specific manner by which horizontally bedded roof strata loses its natural self-supporting ability and the specific means by which reinforcing roof bolts act to promote or retain this natural self-supporting *** Australian coal industry has insisted on minimising bolt-hole diameter to maximise load transfer and on targeting full-encapsulation by any means necessary for many *** has led to a significant, albeit unintended, consequence in terms of overall roof bolting effectiveness, namely increased resin pressures during bolt installation and the associated potential for opening bedding planes that may have, otherwise, remained closed during the bolt installation *** that the natural self-supporting ability of roof strata is strongly linked to whether bedding planes are open or closed, logically, minimising resin pressures should be a significant *** paper focuses primarily on three key issues that relate directly to the function of the roof bolting system itself:(1) the importance of proper resin mixing in the context of maximising load transfer strength and stiffness,(2) the importance of minimising resin pressures developed during bolt installation, and(3) the importance of maximising the effectiveness of the available bolt *** mine operators should be invested in improving the individual effectiveness of each installed roof bolt, even by relatively small incremental amounts, so this is an important topic for discussion within the mining community.

关键词： Roof bolts Strata reinforcement Partial-encapsulation Pre-tension Resin mixing Improved bolt effectiveness

Empirical Model for the Quantitative Prediction of Losses of Radial Fans based on CFD Calculations

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Journal of Thermal Science 2013年第4期22卷 304-310页

作者： Heiko Ratter Saban Caglar martin Gabi Institute of Fluid Machinery Karlsruhe Institute of Technology Kaiserstrasse 1276131 Karlsruhe Germany

In a classical layout process of a fan the quantity of losses is estimated as a sum and expressed in the overall efficiency rote However the characteristic of the pressure rise, the losses and the efficiency rate beside the design point is not known. Against this background a numerical model was developed to calculate quantitative values of occurring losses at radial fan impellers at an early stage in the design process. It allows to estimate the pressure rise and efficiency rate of a given fan geometry at and beside the design point. The physics of losses are described in literature, but obtaining quantitative values is still a challenge. As common in hydraulic theory the losses are calculated with analytic formulas supported by coefficients and efficiency rates, which have to be determined empirically. This paper shows the method how to determine the coefficients for a given radial fan. Therefore a representative radial fan with backward curved blades was designed in reference to classical design guidelines. Performance measuring was done conform to ISO 5801. The flow was calculated at 8 different operation points using CFD methods. The RANS equations are solved by using the SST-k-omega turbulence model. The flow do- main consists of one blade section including inlet channel and outflow chamber. Spatial discretization is done by a block-structured mesh of approx. 1.8 million cells. Performance data show a very good agreement between measurement and calculation.

关键词： loss model radial fan CFD RANS

Perceptual hashing algorithms benchmark suite

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仪器仪表学报 2007年第4期28卷 603-608页

作者： Zhang Hui Schmucker martin Niu Xiamu Harbin Institute of Technology Shenzhen Graduate School Room 304 Building No. 3 HIT Campus Shenzhen 518055 China Fraunhofer IGD Fraunhoferstr 5 Darmstadt 64283 Germany

Numerous perceptual hashing algorithms have been developed for identification and verification of multimedia objects in recent years. Many application schemes have been adopted for various commercial objects. Developers and users are looking for a benchmark tool to compare and evaluate their current algorithms or technologies. In this paper, a novel benchmark platform is presented. PHABS provides an open framework and lets its users define their own test strategy, perform tests, collect and analyze test data. With PHABS, various performance parameters of algorithms can be tested, and different algorithms or algorithms with different parameters can be evaluated and compared easily.

关键词：感觉散列算法 PHABS 基准点识别技术

Epididymosomes： transfer of fertility-modulating proteins to the sperm surface

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Asian Journal of Andrology 2015年第5期17卷 720-725,I0006页

作者： Patricia A martin-DeLeon Department of Biological Sciences University of Delaware Newark DE 19716 USA

A variety of glycosylphosphatidylinositol （GPI）-linked proteins are acquired on spermatozoa from epididymal luminal fluids （ELF） during sperm maturation. These proteins serve roles in immunoprotection and in key steps of fertilization such as capacitation, acrosomal exocytosis and sperm-egg interactions. Their acquisition on sperm cells is mediated both by membrane vesicles （epididymosomes, EP） which were first reported to dock on the sperm surface, and by lipid carriers which facilitate the transfer of proteins associated with the membrane-free fraction of ELF. While the nonvesicular fraction is more efficient, both pathways are dependent on hydrophobic interactions between the GPI-anchor and the external lipid layer of the sperm surface. More recently proteomic and hypothesis-driven studies have shown that EP from several mammals carry transmembrane （TM） proteins, including plasma membrane Ca^2＋-ATPase 4 （PMCA4）. Synthesized in the testis, PMCA4 is an essential protein and the major Ca^2＋ efflux pump in murine spermatozoa. Delivery of PMCA4 to spermatozoa from bovine and mouse EP during epididymal maturation and in vitro suggests that the docking of EP on the sperm surface precedes fusion, and experimental evidence supports a fusogenic mechanism for TM proteins. Fusion is facilitated by CD9, which generates fusion-competent sites on membranes. On the basis of knowledge of PMCA4＇s interacting partners a number of TM and membrane-associated proteins have been identified or are predicted to be present, in the epididymosomal cargo deliverable to spermatozoa. These Ca^2＋-dependent proteins, undetected in proteomic studies, play essential roles in sperm motility and fertility, and their detection highlights the usefulness of the hypothesis-driven approach.

关键词： epididymal maturation epididymal secretory proteins GPI-linked proteins lipid carrier membrane-associated proteins PMCA4 transmembrane proteins

Applicability limits of the DAX test in plastic bonded explosives

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Defence Technology（防务技术） 2024年第6期36卷 64-70页

作者： martin Künzel Jindrich Kucera Jiri Pachman OZM Research Bliznovice 32Hrochuv Tynec 53862Czech Republic Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of PardubiceStudentska 95Pardubice 53210Czech Republic

The Disc Acceleration e Xperiment(DAX)is one of the most recent experimental methods of performance characterization of new energetic materials.A cylindrical explosive charge accelerates a thin metallic disc and its velocity is measured continuously using photonic Doppler *** detonation velocity is measured *** DAX test can be used to obtain the Chapman-Jouguet(CJ)detonation pressure and to describe detonation products expansion using reduced amount of explosive.A series of DAX tests was performed at various charge diameters and disc thicknesses with Semtex 1 A plastic bonded explosive and sensitized *** DAX-like evaluation was also applied to previously measured data of Semtex 1A and A-IX-1 *** optimum disc thickness is determined by the disc to explosive mass ratio of *** repeatability of the Semtex 1 A detonation pressure results is about four times lower compared to the pressed and liquid explosives.

关键词： Flyer plate Detonation pressure Photonic Doppler velocimetry Semtex

Mn_(3)Ag_((1-x))Cu_((x))N antiperovskite thin films with ultra-low temperature coefficient of resistance

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Journal of Materials Science & Technology 2022年第4期99卷 138-147页

作者： Cecil Cherian Lukose Guillaume Zoppi martin Birkett Faculty of Engineering and Environment Northumbria UniversityNewcastle upon Tyne NE18STUnited Kingdom

We demonstrate the first successful attempt to partially substitute Cu into the Mn_(3)AgN-antiperovskite system to form Mn_(3)Ag_((1-x))Cu_((x))N thin films with an ultra-low temperature coefficient of resistance(TCR)for fabrication of ultra-precise passive *** were grown by reactive magnetron sputtering on alumina and glass substrates and were found to be amorphous in nature with highly negative TCR of-233 to-351 ppm/℃in their as-grown *** Cu alloying from x=0 to 1,resulted in increased sheet resistance,a negative shift of TCR and a change of grain morphology from spherical to ***-deposition heat treatment at 300-375℃,resulted in a positive shift of TCR and an ultra-low TCR of-4.66 ppm/℃for films with x=*** heat treatment induces grain growth,surface roughness and the formation of a manganese oxide upper surface layer up until temperatures of 350℃,after which surface oxidation begins to *** growth rate of the surface layer is controlled by the Cu concentration and heat treatment temperature,which both play a central role in the development of these novel ultralow TCR Mn_(3)Ag_((1-x))Cu_((x))N thin film structures.

关键词： Antiperovskite Thin film Sputter deposition Annealing Surface oxidation Near-zero temperature coefficient of resistance

Is there more than one stickiness criterion?

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Friction 2023年第6期11卷 1027-1039页

作者： Anle WANG martin H.MüSER Department of Material Science and Engineering Saarland UniversitySaarbrücken66123Germany INM—Leibniz Institute for New Materials Saarbrücken66123Germany

Adhesion between an elastic body and a smooth,rigid substrate can lead to large tensile stresses between ***,most macroscopic objects are microscopically rough,which strongly suppresses adhesion.A fierce debate has unfolded recently as to whether local or global parameters determine the crossover between small and large ***,we report simulations revealing that the dependence of the pull-off force Fn on the surface energyγdoes not only have two regimes of high and low adhesion but up to four *** are related to contacts,which at the moment of rupture consist of(i)the last individual Hertzian-shaped contact,in which is linear inγ,(ii)a last meso-scale,individual patches with super-linear scaling,(iii)many isolated contact patches with extremely strong scaling,and(iv)a dominating largest contact patch,for which the pull-off stress is no longer negligible compared to the maximum,microscopic pull-off ***(iii)can be seen as a transition *** is located near the point where the surface energy is half the elastic energy per unit area in conformal contact.A criterion for the transition between regimes(i)and(ii)appears difficult to grasp.

关键词： adhesion pull-off force rough contact stickiness

The Bisq decentralised exchange: on the privacy cost of participation

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Blockchain(Research and Applications) 2022年第1期3卷 13-22页

作者： Liam Hickey martin Harrigan Institute of Technology CarlowR93 V960Ireland

The Bisq Trade Protocol and the Bisq DAO(decentralised autonomous organisation)are core components of Bisq,a decentralised cryptocurrency *** Bisq Trade Protocol systematises the peer-to-peer trading of Bitcoin for other currencies and the Bisq DAO decentralises the governance and finance functions of the entire ***,by following the Bisq Trade Protocol and interacting with the Bisq DAO,participants necessarily publish data to the Bitcoin blockchain and broadcast additional data to the Bisq peer-to-peer *** examine the privacy cost to participants in sharing this ***,we use novel address clustering heuristics to construct the one-to-many mappings from participants to addresses on the Bitcoin blockchain and augment the address clusters with data stored within the Bisq peer-to-peer *** describe address clustering heuristics for both the Bisq Trade Protocol and the Bisq *** show that the heuristics aggregate activity performed by each participant:trading,voting,transfers,*** identify instances where participants are operating under multiple aliases,some of which are real-world *** identify the dominant transactors and their role in a two-sided *** conclude with suggestions to better protect the privacy of participants in the future.

关键词： Decentralised exchange Blockchain analysis Decentralised governance Cryptocurrency Privacy

Harnessing neural activity to promote repair of the damaged corticospinal system after spinal cord injury

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Neural Regeneration Research 2016年第9期11卷 1389-1391页

作者： John H.martin Department of Physiology Pharmacology & NeuroscienceCity University of New York School of Medicine

As most spinal cord injuries （SCIs） are incomplete, an important target for promoting neural repair and recovery of lost motor function is to promote the connections of spared descending spinal pathways with spinal motor circuits. Among the pathways, the corticospinal tract （CST） is most associated with skilled voluntary functions in humans and many animals. CST loss, whether at its origin in the motor cortex or in the white matter tracts subcortically and in the spinal cord, leads to movement impairments and paraly- sis. To restore motor function after injury will require repair of the damaged CST. In this review, I discuss how knowledge of activity-dependent development of the CST--which establishes connectional speci- ficity through axon pruning, axon outgrowth, and synaptic competition among CST terminals--informed a novel activity-based therapy for promoting sprouting of spared CST axons after injur in mature animals. This therapy, which comprises motor cortex electrical stimulation with and without concurrent trans-spi- nal direct current stimulation, leads to an increase in the gray matter axon length of spared CST axons in the rat spinal cord and, after a pyramidal tract lesion, restoration of skilled locomotor movements. I discuss how this approach is now being applied to a C4 contusion rat model.

关键词： corticospinal tract motor cortex electrical stimulation spinal direct current stimulation spinalcord injury brain injury