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半导体技术 2003年第12期28卷 9-11页

作者： Gary f.alexander AMC Intl.And Executive Director of SEC/N

Phase field modeling with large driving forces

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npj Computational Materials 2023年第1期9卷 623-631页

作者： Jin Zhang alexander f.Chadwick David L.Chopp Peter W.Voorhees Department of Materials Science and Engineering Northwestern UniversityEvanstonIL 60208USA Department of Engineering Sciences and Applied Mathematics Northwestern UniversityEvanstonIL 60208USA

There is growing interest in applying phase field methods as quantitative tools in materials discovery and ***,large driving forces,common in many materials systems,lead to unstable phase field profiles,thus requiring fine spatial and temporal *** demands more computational resources,limits the ability to simulate systems with a suitable size,and deteriorates the capability of quantitative ***,we develop a strategy to map the driving force to a constant perpendicular to the *** with the third-order interpolation function,we find a stable phase field profile that is independent of the magnitude of the driving *** power of this approach is illustrated using three *** demonstrate that by using the driving force extension method,it is possible to employ a grid size orders of magnitude larger than traditional *** approach is general and should apply to many other phase field models.

关键词： forces interpolation apply

The Role of Vanes in the Damping of Bird feathers

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Journal of Bionic Engineering 2023年第4期20卷 1646-1655页

作者： Kai Deng Hamed Rajabi alexander Kovalev Clemens f.Schaber Zhendong Dai Stanislav N.Gorb functional Morphology and Biomechanics Institute of ZoologyKiel University24098KielGermany School of Engineering London South Bank UniversityLondonSE10AAUK Institute of Bioinspired Structure and Surface Engineering Nanjing University of Aeronautics and AstronauticsNanjing210026People’s Republic of China

Bird feathers sustain bending and vibrations during *** unwanted vibrations could potentially cause noise and flight *** could alter the system response,resulting in improving quiet flight,stability,and *** of feathers are known to be indispensable for supporting the aerodynamic function of the *** relationship between the hierarchical structures of vanes and the mechanical properties of the feather has been previously ***,still little is known about their relationship with feathers’damping ***,the role of vanes in feathers’damping properties was *** vibrations of the feathers with vanes and the bare shaft without vanes after step deflections in the plane of the vanes and perpendicular to it were measured using high-speed video *** presence of several main natural vibration modes was observed in the feathers with *** trimming vanes,more vibration modes were observed,the fundamental frequencies increased by 51-70%,and the damping ratio decreased by 38-60%.Therefore,we suggest that vanes largely increase feather damping *** mechanisms based on the morphology of feather vanes are *** aerodynamic damping is connected with the planar vane surface,the structural damping is related to the interlocking between barbules and barbs,and the material damping is caused by the foamy medulla inside barbs.

关键词： Bird feather Vibrations Damping Bionic

Subnanosecond high-voltage breakdown initiated in high-pressure nitrogen by a runaway electron beam

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High Voltage 2017年第2期2卷 56-59页

作者： alexander G.Burachenko Victor f.Tarasenko Evgenii Kh.Baksht Institute of High Current Electronics SB RAS Tomsk 634055Russia National Research Tomsk State University Tomsk 634050Russia National Research Tomsk Polytechnic University Tomsk 634050Russia

This study reports on subnanosecond breakdowns initiated on high pressure nitrogen by a runaway electron beam in an inhomogeneous electric *** is shown that a diffuse discharge with a duration of≥1 ns is formed in the gas *** are reported for the first time on collector measurements of a supershort avalanche electron beam downstream of an anode foil at a nitrogen pressure of 0.5–1.2 *** beam pulsewidth at these pressures is∼90 *** a nitrogen pressure of 1.2 MPa,the number of electrons with an energy>70 keV recorded by the collector is 4×10^(6)/cm^(2).

关键词： field initiated beam

Chargino Production via Z^0-Boson Decay in a Strong Electromagnetic field

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Chinese Physics Letters 2016年第3期33卷 17-19页

作者： alexander Kurilin Moscow Technological Institute on leave from Moscow State Open Pedagogical University

In the framework of MSSM the probability of Z0-boson decay to chaxginos in a strong electromagnetic field, Z X＋X-, is analyzed. The method of calculations employs exact solutions of relativistic wave equations for charginos in a crossed electromagnetic field. Analytic expression for the decay width is obtained at an arbitrary value of the parameter which characterizes the external-field strength fμv and Z%boson momentum qv. The process Z0→ X＋X- is forbidden in a vacuum for the case of relatively heavy charginos： Mx±mz/2. However, in an intense electromagnetic background this reaction could take place in the region of superstrong fields （x〉1）.

关键词： of on is in Chargino Production via Z~0-Boson Decay in a Strong Electromagnetic field for

four odontocete species change hearing levels when warned of impending loud sound

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Integrative Zoology 2018年第2期13卷 160-165页

作者： Paul E.NACHTIGALL alexander Ya.SUPIN Aude f.PACINI Ronald A.KASTELEIN Hawaii Institute of Marine Biology University of HawaiiKaneohe HawaiiUSA Institute of Ecology and Evolution of the Russian Academy of Sciences MoscowRussia Sea Mammal Research Company(SEAMARCO) Harderwijkthe Netherlands

Hearing sensitivity change was investigated when a warning sound preceded a loud sound in the false killer whale(Pseudorca crassidens),the bottlenose dolphin(Tursiops truncatus),the beluga whale(Delphinaperus leucas)and the harbor porpoise(Phocoena phocoena).Hearing sensitivity was measured using pip-train test stimuli and auditory evoked potential *** the test/warning stimuli preceded a loud sound,hearing thresholds before the loud sound increased relative to the baseline by 13 to 17 *** with multiple frequencies of exposure and shift provided evidence of different amounts of hearing change depending on frequency,indicating that the hearing sensation level changes were not likely due to a simple stapedial reflex.

关键词： change dolphin hearing loud sound

A New foraminiferal Bioindicator for Long-Term Heat Stress on Coral Reefs

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Journal of Earth Science 2022年第6期33卷 1451-1459页

作者： alexander f.Humphreys Sam J.Purkis Chuyan Wan Matthew Aldrich Sarah Nichols Jazmin Garza Rosenstiel School of Marine and Atmospheric Science Department of Marine GeosciencesUniversity of MiamiMiamiFL33149USA Khaled bin Sultan Living Oceans foundation AnnapolisMD21403USA Department of Earth and Planetary Sciences Northwestern UniversityEvanstonIL60208USA

Coral reefs are in terminal *** conservation to be effective,naturally depauperate reefs must be distinguished from those recently degraded by *** reef monitoring is time consuming and lacks the longevity to make this *** in using foraminifera as bioindicators for reef health has hitherto levered their response to *** ocean heat waves are the dominant driver of coral bleaching and death,there is compelling motivation to develop new foraminiferal bioindicators that inform on temperature stress over meaningful *** study focuses on identifying which foraminifera respond systematically to the temperature stress that kills *** models were used to compare endosymbiont-bearing foraminiferal families,collected along a heat-stress gradient spanning the Solomon Islands and New Caledonia,to live coral cover at the same *** indicate that Amphisteginidae foraminifera and coral cover show a significant decline in abundance as heat stress increases along the transect ***,ocean productivity and salinity,both recognized environmental influences on foraminifera,are shown to be subordinate to temperature in their sway of this ecological *** findings indicate the potential for using foraminifera to develop new indices capable of quantifying long-term thermal impacts on reefs.

关键词： foraminifera bioindicator corals bleaching degree heating week foRAM Index

The oscillations in ESR spectra of Hg_(0.76)Cd_(0.24)Te implanted by Ag^+ at the X and Q-bands

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Journal of Semiconductors 2018年第5期39卷 1-5页

作者： A.V.shestakov I.I.fazlizhanov I.V.Yatsyk I.f.Gilmutdinov M.I.Ibragimova V.A.Shustov R.M.Eremina Zavoisky Physical-Technical Institute Federal Research Center "Kazan Scientific Center of RAS" Physics Institute Kazan (Volga Region) Federal University

The objects of the investigation were uniformly Ag~＋ doped Hg_（0.76）Cd_（0.24） Te mercury chalcogenide monocrystals obtained by ion implantation with subsequent thermal annealing over 20 days. After implantation and annealing the conductivity was inverted from n-type with carrier concentration of 10^（16） cm^（-3） to p-type with carrier concentration of ≈ 3.9 × 10^（15） cm^（-3）. The investigations of microwave absorption derivative（d P/d H） showed the existence of strong oscillations in the magnetic field for Ag：Hg_（0.76）Cd_（0.24） Te in the temperature range 4.2–12 K. The concentration and effective mass of charge carrier were determined from oscillation period and temperature dependency of oscillation amplitude. We suppose that this phenomenon is similar to the de Haas–van Alphen effect in weakly correlated electron system with imperfect nesting vector.

关键词： de Haas–van Alphen effect AgHg0.76Cd0.24Te magnetic resonance

Control of stem cell fate by engineering their micro and nanoenvironment

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World Journal of Stem Cells 2015年第1期7卷 37-50页

作者： Michelle f Griffin Peter E Butler alexander M Seifalian Deepak M Kalaskar UCL Division of Surgery and Interventional Science Centre for Nanotechnology and Regenerative Medicine University College London London NW3 2PF United Kingdom Department of Plastic and Reconstructive Surgery Royal Free Hampstead NHS Trust Hospital London NW3 2PF United Kingdom

Stem cells are capable of long-term self-renewal and differentiation into specialised cell types, making them an ideal candidate for a cell source for regenerative medicine. The control of stem cell fate has become a major area of interest in the field of regenerative medicine and therapeutic intervention. Conventional methods of chemically inducing stem cells into specific lineages is being challenged by the advances in biomaterial technology, with evidence highlighting that material properties are capable of driving stem cell fate. Materials are being designed to mimic the clues stem cells receive in their in vivo stem cell niche including topographical and chemical instructions. Nanotopographical clues that mimic the extracellular matrix(ECM) in vivo have shown to regulate stem cell differentiation. The delivery of ECM components on biomaterials in the form of short peptides sequences has also proved successful in directing stem cell lineage. Growth factors responsible for controlling stem cell fate in vivo have also been delivered via biomaterials to provide clues to determine stem cell differentiation. An alternative approach to guide stem cells fate is to provide genetic clues including delivering DNA plasmids and small interfering RNAs via scaffolds. This review, aims to provide an overview of the topographical, chemical and molecular clues that biomaterials can provide to guide stem cell fate. The promising features and challenges of such approaches will be highlighted, to provide directions for future advancements in this exciting area of stem cell translation for regenerative medicine.

关键词： Biomaterials Scaffold Stem cells Surfacetopography Tissue engineering

An Abrupt Rainfall Decrease over the Asian Inland Plateau Region around 1999 and the Possible Underlying Mechanism

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Advances in Atmospheric Sciences 2017年第4期34卷 456-468页

作者： Jinling PIAO Wen CHEN Ke WEI Yong LIU Hans-f.GRAf Joong-Bae AHN alexander POGORELTSEV Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100190China School of Earth Science University of the Chinese Academy of SciencesBeijing 100049China Department of Atmospheric Sciences Pusan National UniversityPusan 609-735Korea Russian State Hydrometeorological University St.Petersburg 195196Russia

A decadal change in summer rainfall in the Asian inland plateau（AIP） region is identified around 1999. This decadal change is characterized by an abrupt decrease in summer rainfall of about 15.7% of the climatological average amount,leading to prolonged drought in the Asian inland plateau region. Both the surface air temperature and potential evapotranspiration in the AIP show a significant increase, while the soil moisture exhibits a decrease, after the late 1990s. furthermore,the normalized difference vegetation index shows an apparent decreasing trend during 1999–2007. Three different drought indices—the standardized precipitation index, the standardized precipitation evapotranspiration index, and the self-calibrating Palmer drought severity index—present pronounced climate anomalies during 1999–2007, indicating dramatic drought exacerbation in the region after the late 1990s. This decadal change in the summer rainfall may be attributable to a wave-like teleconnection pattern from Western Europe to Asia. A set of model sensitivity experiments suggests that the summer warming sea surface temperature in the North Atlantic could induce this teleconnection pattern over Eurasia, resulting in recent drought in the AIP region.

关键词： Asian inland plateau summer rainfall drought teleconnection pattern North Atlantic