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Investigation on the influence of the initial RDX crystal size on the performance of shaped charge warheads

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Defence Technology（防务技术） 2019年第5期15卷 802-807页

作者： f.Majiet f.j.Mostert Rheinmetall Denel Munition Somerset WestSouth Africa Centre for Scientific&Industrial Research PretoriaSouth Africa

Copper lined wave shaped shaped charges of particular design and liner metallurgy were used to investigate the effect of explosive crystal size on the resultant shaped charge jet *** A3 with RDX of three different average crystal sizes,i.e.30μm,100μm and 300μm were used in the *** other parameters in the charge were kept constant and in particular,care was given to obtain consistent dimensional quality and liner microstructure,in order to prohibit the variation of other *** flash-X-ray diagnostics were used in field tests to obtain the jet parameters from multiple firings of similar *** is found that the varying crystal size of the RDX has a marginal influence in the total jet length of the ***,it is also found that there is less variation between firings in the jet parameters for jets from the charges loaded with the crystal size of 100 μm.

关键词： shaped size crystal

2022 Emerging Investigator Issue of Science China Chemistry

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Science China Chemistry 2022年第11期65卷 2045-2050页

作者： Li-jun wan Institute of Chemistry Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

It is always my pleasure to introduce and promote young scientists to the scientific *** this end,Science China Chemistry(SCC)organized special issues for emerging investigators,namely Emerging Investigator Issue[1,2].Starting from 2020,these issues published innovative research work from young scientists who are at an early stage of their independent research *** results in these papers have attracted widespread attention and all authors are highly evaluated by the editorial board.

关键词： Issue young innovative

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Biostratigraphy of a Paleocene-Eocene foreland Basin boundary in southern Tibet

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Geoscience frontiers 2010年第1期1卷 69-79页

作者： Xiaoqiao wan Xi wang Luba f. jansa China University of Geosciences 29 Xueyuan Road Beijing 100083 China Department of Earth Sciences Dalhousie University Halifax N.S. Canada

This study of the Paleocene--Eocene boundary within a foreland basin of southern Tibet, which was dominated by a carbonate ramp depositional environment, documents more complex environmental conditions than can be derived from studies of the deep oceanic environment. Extinction rates for larger foraminiferal species in the Zongpu-1 Section apply to up to 46% of the larger foraminiferal taxa. The extinction rate in southern Tibet is similar to rates elsewhere in the world, but it shows that the Paleocene fauna disappeared stepwise through the Late Paleocene, with Eocene taxa appearing abruptly above the boundary. A foraminifera turnover was identified between Members 3 and 4 of the Zongpu formation-from the Miscellanea--Daviesina assemblage to an Orbitolites-Alveolina assemblage. The Paleocene and Eocene boundary is between the SBZ 4 and SBZ 5, where it is marked by the extinction of Miscellanea miscella and the first appearance of Alveolina ellipsodalis and a large number of Orbitolites. Chemostratigraphically, the δ^13C values from both the Zongpu-1 and Zongpu-2 Sections show three negative excursions in the transitional strata, one in Late Paleocene, one at the boundary, and one in the early Eocene. The second negative excursion of δ^13C, which is located at the P-E boundary, coincides with larger foraminifera overturn. These faunal changes and the observed δ^13C negative excursions provide new evidence on environmental changes across the Paleocene--Eocene boundary in Tibet.

关键词： Paleocene Eocene foraminifera Carbon stable isotope Tibet

Implementation of a Roughness Element to Trip Transition in Large-eddy Simulation

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journal of Thermal Science 2015年第1期24卷 30-36页

作者： j.Boudet j.-f.Monier f.Gao LMfA Ecole Centrale de Lyon Université de Lyon–UMR CNRS 5509 69134 Ecully Cedex France PhD.Candidate Université de Lyon–UMR CNRS 5509 69134 Ecully Cedex France

In aerodynamics, the laminar or turbulent regime of a boundary layer has a strong influence on friction or heat transfer. In practical applications, it is sometimes necessary to trip the transition to turbulent, and a common way is by use of a roughness element （e.g. a step） on the wall. The present paper is concerned with the numerical im- plementation of such a trip in large-eddy simulations. The study is carried out on a flat-plate boundary layer con- figuration, with Reynolds number Rex=l.3x 106. first, this work brings the opportunity to introduce a practical methodology to assess convergence in large-eddy simulations. Second, concerning the trip implementation, a volume source term is proposed and is shown to yield a smoother and faster transition than a grid step. Moreover, it is easier to implement and more adaptable. finally, two subgrid-scale models are tested： the WALE model of Nic0ud and Ducros （flow Turbul. Combust., vol. 62, 1999） and the shear-improved Smagorinsky model of Ldv^que et al. （j. fluid Mech., vol. 570, 2007）. Both models allow transition, but the former appears to yield a faster transition and a better prediction of friction in the turbulent regime.

关键词： large-eddy simulation boundary layer roughness element transition tripping

Peritidal carbonate cycles induced by carbonate productivity variations:A conceptual model for an isolated Early Triassic greenhouse platform in South China

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journal of Palaeogeography 2014年第2期3卷 115-126页

作者： wan Yang Dan j.Lehrmann Geology and Geophysics Program Missouri University of Science and Technology Department of Geosciences Trinity University

Eustasy has commonly been invoked to explain peritidal carbonate cyclicity,but is difficult to explain cycles formed in a greenhouse climate when eustasy is *** propose that peritidal cycles on an Early Triassic isolated carbonate platform in Guizhou,South China,were formed by hierarchical carbonate productivity *** of the 149 shallowing-upward cycles are typically terminated by flooding over intertidal facies and contain rare supratidal facies and no prolonged subaerial ***-diversity benthos in the platform interior during the post-end-Permian biotic recovery were sensitive to environmental perturbations,which caused variations in benthic sediment productivity in the subtidal carbonate *** perturbations may be driven by changes in salinity and degree of eutrophication,or repeated platform mini-drowning by anoxic and/or CO2-charged deep water upwelled onto the *** were modulated by Milankovitch orbitally-driven climatic and oceanographic factors as suggested by the hierarchical stacking pattern and spectral signals of these cycles.A one-dimensional conceptual model shows that hierarchical productivity variations alone may generate hierarchical peritidal carbonate cycles under conditions of constant subsidence and no sea-level fluctuation.

关键词： carbonate peritidal cycle productivity climate Triassic South China

Evaluation on Moisture Resistance of Asphalt Mixture with Active Mineral Powder

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武汉理工大学学报 2010年第17期32卷 210-214页

作者： XIE j WU S P wan L Key Laboratory of Silicate Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

A new type of filler named 'active mineral powder' (AMP) was introduced and applied in asphalt mixture in order to improve the adhesive property of gneiss or granite aggregates and asphalt. The treated mixtures contained 2% AMP by weight of the total aggregates as filler. The moisture stabilization properties of various combined mixtures were analyzed using the adhesive test,Marshall stability and indirect tensile strength tests. five frost-thaw cycles test was conducted to further investigate the effect of active filler on asphalt mixtures in the indirect tensile strength experiment. The results show that active filler improves the moisture stability of mixtures with gneiss and granite. The active mechanism of AMP was also discussed in this paper.

关键词： gneiss granite moisture destruction active mineral powder

Phosphorus Ligands from the Zhang Lab:Design,Asymmetric Hydrogenation,and Industrial Applications

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Chinese journal of Chemistry 2021年第4期39卷 954-968页

作者： feng wan Wenjun Tang State Key Laboratory of Bio-Organic&Natural Products Chemistry Shanghai Institute of Organic ChemistryChinese Academy of Sciences345 Lingling RoadShanghai200032 China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences1 Sub-lane XiangshanHangzhouZhejiang310024 China

Chiral phosphorus ligands have played a crucial role for the recent advances in asymmetric *** review summarizes chiral phosphorus ligands developed from the Laboratory of Professor Xumu Zhang in the latest 25 years.A number of iconic phosphorus ligands including bisphosphorus ligands with rigid chiral backbone such as BICP,PennPhos,TunePhos,and f-Binaphane,P-chiral bisphosphorus ligands TangPhos,Binapine,and DuanPhos,phosphine-phosphoramidte ligand YanPhos,noncovalent interaction-assisted ferrocenyl phosphorus ligand ZhaoPhos and WudaPhos,and tridentate ferrocenyl phosphorus ligands f-amphox are introduced,and their applications in asymmetric hydrogenation are emphasized.

关键词： Phosphorus ligands Xumu Zhang Hydrogenation Ligand design Industrial applications

Microstructure and Peritectic Reaction within As-solidified Mg-Zn-Y Alloy

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journal of Materials Science & Technology 2008年第3期24卷 317-320页

作者： Diqing wan Gencang YANG State Key Laboratory of Solidification Processing Northwestern Polytechnial University Xi＇an 710072 China

An investigation on the microstructure and peritectic reaction involving icosahedra phase （I-phase） and crystalline phase （W-phase） within Mg-Zn-Y alloy during conventional solidification technology and rapid quenching was carried out, The solidification process of the peritectic reaction is discussed in details, It is shown that there is no obvious crystallographic relationship between the W-phase and I-phase during the solidification of Mg-Zn-Y alloy.

关键词： Mg-Zn-Y alloys I-phase Peritectic microstructures Solidification

DATA DRIVEN MODELING fOR POWER TRANSfORMER LIfESPAN EVALUATION

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journal of Systems Science and Systems Engineering 2014年第1期23卷 80-93页

作者： Charles V.TRAPPEY Amy j.C.TRAPPEY Lin MA wan-Ting TSAO Department of Management Science National Chiao Tung University Department of Industrial Engineering and Engineering Management National Tsing Hua University School of Chemistry Physics and Mechanical EngineeringQueensland University of Technology

Large sized power transformers are important parts of the power supply chain. These very critical networks of engineering assets are an essential base of a nation＇s energy resource infrastructure. This research identifies the key factors influencing transformer normal operating conditions and predicts the asset management lifespan. Engineering asset research has developed few lifespan forecasting methods combining real-time monitoring solutions for transformer maintenance and replacement. Utilizing the rich data source from a remote terminal unit （RTU） system for sensor-data driven analysis, this research develops an innovative real-time lifespan forecasting approach applying logistic regression based on the Weibull distribution. The methodology and the implementation prototype are verified using a data series from 161 kV transformers to evaluate the efficiency and accuracy for energy sector applications. The asset stakeholders and suppliers significantly benefit from the real-time power transformer lifespan evaluation for maintenance and replacement decision support.

关键词： Condition based maintenance (CBM) prognostics and health management (PHM) logisticregression remaining life prediction sustainable engineering asset management