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Distinct Modes of Winter Arctic Sea Ice Motion and Their Associations with Surface Wind Variability

Advances in Atmospheric Sciences 2010年第2期27卷 211-229页

作者：武炳义 Mark A. johnson Chinese Academy of Meteorological Sciences Arctic Region Supercomputing Center University of Alaska Fairbanks Institute of Marine Science University of Alaska Fairbanks

Using monthly mean sea ice velocity data obtained from the International Arctic Buoy Programme （IABP） for the period of 1979–1998 and the monthly mean NCEP/NCAR re-analysis dataset （1960–2002）, we investigated the spatiotemporal evolution of the leading sea ice motion mode （based on a complex correlation matrix constructed of normalized sea ice motion velocity） and their association with sea level pressure （SLP） and the predominant modes of surface wind field variability. The results indicate that the leading winter sea ice motion mode’s spatial evolution is characterized by two alternating and distinct sea ice modes, or their linear combination. One mode （M1） shows a nearly closed cyclonic or anti-cyclonic circulation anomaly in the Arctic Basin and its marginal seas, resembling to a large extent the response of sea ice motion to the Arctic Oscillation （AO）, as many previous studies have revealed. The other mode （M2） displays a coherent cyclonic or anti-cyclonic circulation anomaly with its center close to the Laptev Sea, which has not been identified in previous observational studies. In fact, M1 and M2 respectively reflect the responses of sea ice motion to two predominant modes of winter surface wind variability north of 70 ？ N, which well correspond, with slight differences, to the first two modes of EOF analysis of winter monthly mean SLP north of 70 ？ N. These slight differences in SLP anomalies lead to a difference of M2 from the response of sea ice motion to the dipole anomaly. Although the AO significantly influences sea ice motion, it is not crucial for the existence of M1. The new sea ice motion mode （M2） has the largest variance and clearly differs from the response of winter monthly mean sea ice motion to the dipole anomaly in SLP fields, and corresponding SLP anomalies also show differences compared to the dipole anomaly. This study indicates that in the Arctic Basin and its marginal seas, slight differences in SLP anomaly patterns can force distinctl

关键词： distinct mode Arctic sea ice motion Arctic surface wind forcing

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Comparison of a Spectral Bin and Two Multi-Moment Bulk Microphysics Schemes for Supercell Simulation:Investigation into Key Processes Responsible for Hydrometeor Distributions and Precipitation

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Advances in Atmospheric Sciences 2024年第5期41卷 784-800页

作者： Marcus johnson Ming XUE Youngsun JUNG Center for Analysis and Prediction of Storms University of OklahomaNormanOK 73072USA School of Meteorology University of OklahomaNormanOK 73072USA Office of Science and Technology Integration National Weather ServiceSilver SpringMD 20910USA

There are more uncertainties with ice hydrometeor representations and related processes than liquid hydrometeors within microphysics parameterization(MP)schemes because of their complicated geometries and physical *** supercell simulations are produced using the WRF model coupled with“full”Hebrew University spectral bin MP(HU-SBM),and NSSL and Thompson bulk MP(BMP)***-SBM downdrafts are typically weaker than those of the NSSL and Thompson simulations,accompanied by less rain ***-SBM produces more cloud ice(plates),graupel,and hail than the BMPs,yet precipitates less at the *** limiting mass bins(and subsequently,particle size)of rimed ice in HU-SBM and slower rimed ice fall speeds lead to smaller melting-level net rimed ice fluxes than those of the *** from plates in HU-SBM,together with snow–graupel collisions,leads to a greater snow contribution to rain than those of the *** HU-SBM’s fall speeds using the formulations of the BMPs after aggregating the discrete bin values to mass mixing ratios and total number concentrations increases net rain and rimed ice ***,they are smaller in magnitude than bulk rain,NSSL hail,and Thompson graupel net fluxes near the ***,the melting-layer net rimed ice fluxes are reduced when the fall speeds for the NSSL and Thompson simulations are calculated using HU-SBM fall speed formulations after discretizing the bulk particle size distributions(PSDs)into spectral *** results highlight precipitation sensitivity to storm dynamics,fall speed,hydrometeor evolution governed by process rates,and MP PSD design.

关键词： precipitation spectral bin microphysics bulk microphysics parameterization microphysics processes WRF model supercell storm

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Hoare logic-based genetic programming

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Science China(Information Sciences) 2011年第3期54卷 623-637页

作者： johnson Colin G. Computing Laboratory University of Kent

Almost all existing genetic programming systems deal with fitness evaluation solely by testing. In this paper, by contrast, we present an original approach that combines genetic programming with Hoare logic with the aid of model checking and finite state automata, henceby proposing a brand new verification-focused formal genetic programming system that makes it possible to evolve reliable programs with mathematically-verified properties.

关键词： genetic programming program verification Hoare logic model checking finite state automata

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Modeling grammatical evolution by automaton

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Science China(Information Sciences) 2011年第12期54卷 2564-2573页

作者： Colin G.johnson School of Computing University of Kent

Twelve years have passed since the advent of grammatical evolution (GE) in 1998, but such issues as vast search space, genotypic readability, and the inherent relationship among grammatical concepts, production rules and derivations have remained untouched in almost all existing GE researches. Model-based approach is an attractive method to achieve different objectives of software engineering. In this paper, we make the first attempt to model syntactically usable information of GE using an automaton, coming up with a novel solution called model-based grammatical evolution (MGE) to these problems. In MGE, the search space is reduced dramatically through the use of concepts from building blocks, but the functionality and expressiveness are still the same as that of classical GE. Besides, complex evolutionary process can visually be analyzed in the context of transition diagrams.

关键词： genetic programming grammatical evolution finite state automaton model

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Antifragility Analysis and Measurement Framework for Systems of Systems

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International Journal of Disaster Risk Science 2013年第4期4卷 159-168页

作者： John johnson Adrian V.Gheorghe Engineering Management and Systems Engineering Department Old Dominion University Norfolk VA 23529 USA

The twenty-first century is defined by the social and technical hazards we face.A hazardous situation is a condition,or event,that threatens the well-being of people,organizations,societies,environments,and *** most extreme of the hazards are considered X-Events and are an exogenous source of extreme stress to a system.X-Events can also be the unintended outputs of a system with both positive(serendipitous) and negative(catastrophic) *** can vary in their ability to withstand these stress *** ability exists on a continuum of fragility that ranges from fragile(degrading with stress),to robust(unchanged by stress),to antifragile(improving with stress).The state of the art does not include a method for analyzing or measuring *** that “what we measure we will improve,” the absence of a measurement approach limits the effectiveness of governance in making our systems less fragile and more robust if not *** authors present an antifragile system simulation model,and propose a framework for analyzing and measuring antifragility based on system of systems *** framework reduces a multidimensional concept of fragility into a two-dimensional continuous interval scale.

关键词： extreme unchanged consequences

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RADICAL GRAFTING REACTIONS ONTO STARCH AND OTHER WATER-SOLUBLE COPOLYMERS IN ISOLATED GEL DROPLETS

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Chinese Journal of Polymer Science 1993年第2期11卷 144-152页

作者：张连生 A.F.johnson Department of Chemistry and Chemical Technology University of Bradford Bradford BD7 IDP England Dpt.Chem.Heilongjiang Universiry24 Xuefu Road Harbin 150080 China Received December 231991. Department of Chemistry and Chemical Technology University of Bradford Bradford BD7 IDP England

A novel radical grafting copolymerization process has been designed for water-soluble polymers which avoids the problems of conducting grafting reactions in highly viscous polymerization media. A variety of water-soluble graft copolymers having starch or dextran as the backbone chain with grafted side chains of polyacrylamide (—AM—), poly (acrylic acid ) (—AA—), poly (acrylamide-co-acrylic acid) (—AM—NH_4AA—) or poly ( acrylamide-co-2-acryiamido-2-methyl-l-propanesulphinic acid) (—AM—AMPS—) have been synthesized in gel droplets using aceric sulphate redox initiator, and their properties compared. The reaction conditions were optimized taking into account reaction kinetic data and the observed properties of the products produced under different reaction conditions. The effects of the ratios of [backbone]/[graft monomer], [ AM]/[ AA]/[AMPS] , [Ce^(4+)]/[ S_2O_8=] and pH value on the reaction rate , conversion, grafting degree, grafted chain length and the product molecular weight have been investigated.

关键词： Radical grafting copolymerization Isolated gel droplets, Acrylamide Starch Kinetics

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Void fill and support techniques to stabilize drift excavated through a transition zone mined by a TBM at the Stillwater mine

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International Journal of Mining Science and Technology 2017年第1期27卷 71-76页

作者： johnson Josh Jacobs Curt Ferster Mark Tadolini Stephen Stillwater Mining Company NyeMT 59061USA Minova GeorgetownKYUSA

Stillwater Mining Company is the only U.S. producer of platinum group metals （PGMs） and the largest producer outside of South Afiica and Russia. The company controls a considerable portion of the J-M reef and is currently developing the ＂Blitz Project,＂ which will provide a main haulage level, ore pass systems, backfill plants, and fiow-through ventilation to increase production and ensure sustainable extraction of this critical strategic mineral. While driving two sub-parallel footwall laterals 8125 m in length, one of the development drifts experienced a massive fall in a geologically disturbed area created by a mafic dike intrusion. Combinations of a void fill material （Tekseal）, polyurethane injection, fore poling coupled with steel arches, and supplemental bolting allow safe and efficient advance through this geologically dis- turbed zone. This paper presents the details of this project.

关键词： TBM Ground Dike Cutterhead

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Evaluation of the 20 L dust explosibility testing chamber and comparison to a modified 38 L vessel for underground coal

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International Journal of Mining Science and Technology 2018年第6期28卷 885-890页

作者： Robert Eades Kyle Perry Catherine johnson Jacob Miller Department of Mining and Nuclear Engineering Missouri University of Science and Technology

The phenomenon of combustible dust explosions is present within many industries. Tests for explosibility of dust clouds per ASTM E1226 use a 20 L explosive chamber that places the combustible dust directly below the dispersion nozzle which generates a thorough mixture for testing purposes. However, in the underground coal mining industry, there are a number of geologic, mining, and regulatory factors that change the deposition scheme of combustible coal dust. This causes the atmosphere of a coal mine to have a variable rock dust-coal dust mixture at the time of ignition. To investigate the impact of this variable atmosphere, a series of lean explosibility tests were conducted on a sample of Pittsburgh Pulverized coal dust. These explosibility tests were conducted in a 38 L chamber with a 5 kJ Sobbe igniter. The 38 L chamber generates a variable air-dust mixture prior to ignition. The test results indicate that the 38 L chamber experiences reduced explosive pressures, and lower explosibility index values when compared to the 20 L chamber.

关键词： Dust explosion Coal mining Coal dust Explosibility testing

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A new approach for deposition of silver film from AgCl through successive ionic layer adsorption and reaction technique

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Journal of Central South University 2017年第12期24卷 2793-2798页

作者： johnson Henry Arockiasamy Ajaypraveenkumar Ganesan Sivakumar Kannusamy Mohanraj Department of Physics Manonmaniam Sundaranar University Tirunelveli-627 012 Tamil Nadu India CISL Department of Physics Annamalai University Annamalai nagar-608 002 Tamil Nadu India

An attempt was made to deposit thin film of silver onto the glass substrate by using Ag Cl precursor, instead of conventional precursor AgNO_3 with vitamin C by inexpensive and convenient successive ionic layer adsorption and reaction(SILAR) method. The deposited silver thin film was characterized by X-ray diffraction(XRD) analysis, scanning electron microscope(SEM), UV-visible and electrical I-V study. The diffraction study showed FCC structure of metallic silver in good agreement with the standard values of JCPDS(04–0783). SEM reveals flower like nano particles produced on the substrate. The surface plasmon resonance(SPR) peak in the UV-visible spectrum shows maximum absorption at 350 nm. The film shows an ohmic behavior and its electrical resistivity was found ~103 ?·cm at room temperature.

关键词： thin films metals materials characterization sol-gel optical properties silver

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Growth characteristics of algae during early stages of phytoplankton bloom in Lake Taihu,China

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Journal of Environmental Sciences 2013年第2期25卷 254-261页

作者： Yuhong Jia johnson Dan Min Zhang Fanxiang Kong State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences Graduate School of Chinese Academy of Sciences Water and Environmental Science Building Department of GeographyUniversity of LethbridgeLethbridgeAlbertaT1K 3M4Canada

Three treatments, sediment plus lake water （S＋W）, sterilized sediment plus lake water （SS＋W）, and sediment plus filtered lake water （S＋FW）, were recruited to investigate the growth characteristics of algae during pre-bloom and the importance of algal inocula in the water column and sediment. The results showed that in the water column, biomass of all algae increased in all treatments when recruitment was initiated, whereas this tendency differed among treatments with further increment of temperature. The process of algal growth consisted of two stages： Stage I, the onset of recruitment and Stage II, the subsequent growth of algae. Compared with S＋W, in Stage I, SS＋W significantly increased the biomass of cyanophytes by 178.70%, and decreased the biomass of non-cyanophytes by 43.40%; In Stage II, SS＋W notably stimulated the growth of all algae, thus incurring the occurrence of phytoplankton bloom. Further analyses revealed that both metabolic activity and photochemical activity of algae were enhanced in SS＋W, which resulted from the releasing of nutrients from sediment. These results suggest that algal growth in Stage II and algal inocula in the water column can be important factors for the formation of phytoplankton bloom. In addition, possible mechanisms promoting algal recruitment and subsequent growth of algae were explored.

关键词： algae recruitment phytoplankton bloom water column sediment

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