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Some Penrose transforms in complex differential geometry Dedicated to Professor Sheng GONG on the occasion of his 75th birthday

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Science China Mathematics 2006年第11期49卷 1599-1610页

作者： ANCO stephen BLAND John EASTWOOD Michael Department of Mathematics Brock University 500 Glenridge AvenueSt. CatharinesON L2S 3A1Canada Department of Mathematics University of Toronto 100 St. George StreetTorontoON M5S 3G3Canada Department of Mathematics University of Adelaide SA 5005Australia

In this article, we review a construction in the complex geometry often known as the Penrose transform. We then present two new applications of this transform. One concerns the construction of symmetries of the massless field equations from mathematical physics. The otherconcerns obstructions to the embedding of CR structures on the three-sphere.

关键词： Penrose transform, symmetries, massless fields, CR embedding.

Toward pluripotency by reprogramming:mechanisms and application

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Protein & Cell 2013年第11期4卷 820-832页

作者： Tao Wang stephen TWarren Peng Jin Department of Human Genetics Emory UniversityAtlantaGA 30322USA Genetics and Molecular Biology Graduate Program Emory UniversityAtlantaGA 30322USA

The somatic epigenome can be reprogrammed to a pluri-potent state by a combination of transcription *** cell fate involves transcription factors coopera-tion,epigenetic reconfi guration,such as DNA methylation and histone modification,posttranscriptional regulation by microRNAs,and so ***,such reprogram-ming is *** suggests that during the early stage of reprogramming,the process is stochastic,but by the late stage,it is *** addition to con-ventional reprogramming methods,dozens of small mol-ecules have been identifi ed that can functionally replace reprogramming factors and signifi cantly improve induced pluripotent stem cell(iPSC)***,iPS cells have been created recently using chemical com-pounds *** are thought to display subtle genetic and epigenetic variability;this variability is not random,but occurs at hotspots across the *** we dis-cuss the progress and current perspectives in the fi *** into the reprogramming process today will pave the way for great advances in regenerative medicine in the future.

关键词： epigenetic reprogramming induced pluripo-tent stem cells embryonic stem cells disease modeling

Recovery of Baikiaea forest of southwestern Zambia from shifting cultivation and its implications for sustainable management

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Journal of Forestry Research 2019年第2期30卷 497-506页

作者： Filipo Zulu stephen Syampungani Peter Fushike National Science and Technology Council (NSTC) School of Natural Resources Copperbelt University

We studied the dominant species by age category of re-growth, and how subsistence forest use through shifting cultivation impacted on the floristic composition of Baikiaea forest. For re-growth stands, variable sampling method was adopted in data collection while in mature stands, a sample plot size of 50 m 9 50 m was used at each of three study sites. Distribution of species by age categories showed that shrub, herb, and grass species were abundant in young re-growth stands while woody vegetation became common with increasing age of the re-growth stand. Hierarchical clustering for common woody species showed several species associations with age categories and also with relatively undisturbed woodland. Common regeneration mechanisms of key woody species were mainly by seed(48%), coppicing(40%) and root suckers(12%). The young re-growth stands of 6–10 and 11–15 years were characterized by B. petersiana, ***, Combretum zeyheri, and Guibourtia coleosperma. Older stands(16–20 years after abandonment) were characterized by B. plurijuga, Pterocarpus antunesii, and Baphia massiensis, thus closely mimicking the relatively undisturbed forest whose dominant key woody species were B. plurijuga, P. antunesii, and G. coloesperma. There were many stems in younger stands(2–5 years) and fewer stems in older re-growth stands of 16–20 years after abandonment following shifting cultivation. Older regrowth stands(16–20 years) were similar to undisturbed stands(P \ 0.005). The similarity between re-growth stands of 16–20 years and control stands demonstrates the recovery of Baikiaea forest over time after cessation of shifting agriculture. Baikiaea forest requires some disturbance to perpetuate the dominant species and begins to show signs of recovery from shifting cultivation within16–20 years after abandonment. This is contrary to assertions that this ecosystem could take up to about 100 years for abandoned fields to begin showing signs of

关键词： Regeneration dynamics Species diversity Tree species dominance Management model Shifting cultivation

Energy cost minimization through optimization of EV, home and workplace battery storage

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Science China(Technological Sciences) 2018年第5期61卷 761-773页

作者： ZHONG QianWen BUCKLEY stephen VASSALLO Anthony SUN YiZe School of Mechanical Engineering Donghua University Faculty of Engineering & Information Technologies University of Sydney

Besides grid-to-vehicle(G2 V) and vehicle-to-grid(V2 G) functions, the battery of an electric vehicle(EV) also has the specific feature of mobility. This means that EVs not only have the potential to utilize the storage of cheap electricity for use in high energy price periods, but can also transfer energy from one place to another place. Based on these special features of an EV battery, a new EV energy scheduling method has been developed and is described in this article. The approach is aimed at optimizing the utilization EV energy for EVs that are regularly used in multiple places. The objective is to minimize electricity costs from multiple meter points. This work applies real data in order to analyze the effectiveness of the method. The results show that by applying the control strategy presented in this paper at locations where the EVs are parked, the electricity cost can be reduced without shifting the demand and lowering customer's satisfaction. The effects of PV size and number of EVs on our model are also analyzed in this paper. This model has the potential to be used by energy system designers as a new perspective to determine optimal sizes of generators or storage devices in energy systems.

关键词： electric vehicle electric vehicle(EV) optimization energy management storage battery vehicle to grid(V2G)

Simpler Mass Production of Polymeric Visual Decoys for the Male Emerald Ash Borer （Agrilusplanipennis）

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Journal of Bionic Engineering 2015年第2期12卷 263-269页

作者： Tarun Gupta stephen E. Swiontek Akhlesh Lakhtakia Department of lndustrial and Manufacturing Engineering Western Michigan University Kalamazoo Michigan 49008 USA Department of Engineering Seience & Mechanics Pennsylvania State University Univelitv Park Pennwlvania 16802 USA

Polymeric visual decoys of beetle of an invasive species called the Emerald Ash Borer （EAB）, Agrilus planipennis, are highly efficacious in luring and trapping EAB males. Although industrially scalable, the bioreplication process to t）tbricate these decoys involves several operational steps. In a simpler bioreplication process devised by us, a multi-cavity negative die of nickel is made from an array of several EAB females. This die is used to fabricate multiple decoys simultaneously by casting and ihermal curing of poly（dimethyl siloxane）. Finally, the decoys are sprayed by first a black paint and then a metallic green paint. The new bioreplication process has considerably fewer operational steps than its predecessor and can be adopted by industry.

关键词： artificial visual decoy bioreplication Confomlal-Evaporated-Film-by-Rotation (CEFR) method electroforming,Emerald Ash Borer negative die

A Novel Framework for Object-Based Coding and Compression of Hyperspectral Imagery

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Chinese Journal of Electronics 2015年第2期24卷 300-305页

作者： ZHAO Chunhui LI Xiaohui REN Jinchang stephen Marshall College of Information and Communication Engineering Harbin Engineering University Department of Electronic and Electrical Engineering University of Strathclyde

A novel object-based framework is proposed for HSI compression, where targets of interest are extracted and separately coded. With objects removed,the holes are filled with the background average to form a new but more homogenous background for better compression. An improved sparse representation with adaptive spatial support is proposed for target detection. By applying the proposed framework to 2D/3D DCT approaches,reconstructed images from conventional and proposed approaches are compared. Six criteria in three groups are employed for quantitative evaluations to measure the degree of data reduction, the distortion of reconstructed image quality and accuracy in target detection, respectively. Comprehensive experiments on two datasets are used for performance evaluation. It is found that the proposed approaches yield much improved results.

关键词： Hyperspectral imagery(HSI) Objectbased image compression Sparse representation Target detection Remote sensing

Populations with individual variation in dispersal in heterogeneous environments: Dynamics and competition with simply diffusing populations

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Science China Mathematics 2020年第3期63卷 441-464页

作者： Robert stephen Cantrell Chris Cosner Xiao Yu Department of Mathematics University of MiamiCoral GablesFL 33146USA School of Mathematical Sciences South China Normal UniversityGuangzhou 510631China

We consider a model for a population in a heterogeneous environment, with logistic-type local population dynamics, under the assumption that individuals can switch between two different nonzero rates of diffusion. Such switching behavior has been observed in some natural systems. We study how environmental heterogeneity and the rates of switching and diffusion affect the persistence of the population. The reactiondiffusion systems in the models can be cooperative at some population densities and competitive at others. The results extend our previous work on similar models in homogeneous environments. We also consider competition between two populations that are ecologically identical, but where one population diffuses at a fixed rate and the other switches between two different diffusion rates. The motivation for that is to gain insight into when switching might be advantageous versus diffusing at a fixed rate. This is a variation on the classical results for ecologically identical competitors with differing fixed diffusion rates, where it is well known that "the slower diffuser wins".

关键词： reaction-diffusion ecology and evolutionary biology population dynamics animal behavior individual variation in dispersal evolution of dispersal

The origin of the lattice thermal conductivity enhancement at the ferroelectric phase transition in GeTe

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npj Computational Materials 2021年第1期7卷 529-536页

作者： Đorđe Dangić Olle Hellman stephen Fahy Ivana Savić Department of Physics University College CorkCorkIreland Tyndall National Institute CorkIreland Department of Physics Chemistry and Biology(IFM)Linköping UniversityLinköpingSweden

The proximity to structural phase transitions in IV-VI thermoelectric materials is one of the main reasons for their large phonon anharmonicity and intrinsically low lattice thermal conductivityκ.However,theκof GeTe increases at the ferroelectric phase transition near 700 *** first-principles calculations with the temperature dependent effective potential method,we show that this rise inκis the consequence of negative thermal expansion in the rhombohedral phase and increase in the phonon lifetimes in the high-symmetry *** anharmonicity near the phase transition induces non-Lorentzian shapes of the phonon power *** account for these effects,we implement a method of calculatingκbased on the Green-Kubo approach and find that the Boltzmann transport equation underestimatesκnear the phase *** findings elucidate the influence of structural phase transitions onκand provide guidance for design of better thermoelectric materials.

关键词： phase transition ferroelectric

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