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Enhancement of THz generation in LiNbO_(3) waveguides via multi-bounce velocity matching

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Light(Science & Applications) 2022年第12期11卷 2994-3001页

作者： blake S.Dastrup Eric r.Sung Frank Wulf Clara Saraceno Keith A.Nelson Department of Chemistry Massachusetts Institute of TechnologyCambridgeMA 02139USA Faculty of Electrical Engineering and Information Technology Ruhr University BochumBochum 44801Germany

To realize the full promise of terahertz polaritonics(waveguide-based terahertz field generation,interaction,and readout)as a viable spectroscopy platform,much stronger terahertz fields are needed to enable nonlinear and even robust linear terahertz *** use a novel geometric approach in which the optical pump is totally internally reflected to increase the distance over which optical rectification *** matching is achieved by tuning the angle of internal *** doing this,we are able to enhance terahertz spectral amplitude by over 10x compared to conventional single-pass terahertz *** analysis of the depletion mechanisms reveals that 3-photon absorption and divergence of the pump beam are the primary limiters of further *** level of enhancement is promising for enabling routine spectroscopic measurements in an integrated fashion and is made more encouraging by the prospect of further enhancement by using longer pump wavelengths.

关键词： pump waveguide tuning

LINEAr WAVES THAT EXPrESS THE SIMPLEST POSSIBLE PErIODIC STrUCTUrE OF THE COMPrESSIBLE EULEr EQUATIONS

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Acta Mathematica Scientia 2009年第6期29卷 1749-1766页

作者： blake Temple robin Young Department of Mathematics University of California Davis CA 95616 USA Department of Mathematics and Statistics University of Massachusetts Amherst MA 01003 USA

In this paper we show how the simplest wave structure that balances compression and rarefaction in the nonlinear compressible Euler equations can be represented in a solution of the linearized compressible Euler equations. Such waves are exact solutions of the equations obtained by linearizing the compressible Euler equations about the periodic extension of two constant states separated by entropy jumps. Conditions on the states and the periods are derived which allow for the existence of solutions in the Fourier 1-mode. In [3, 4, 5] it is shown that these are the simplest linearized waves such that, for almost every period, they are isolated in the kernel of the linearized operator that imposes periodicity, and such that they perturb to nearby nonlinear solutions of the compressible Euler equations that balance compression and rarefaction along characteristics in the formal sense described in [3]. Their fundamental nature thus makes them of interest in their own right.

关键词： compressible Euler periodic solutions conservation laws

Using physiological conditions to assess current and future habitat use of a Subarctic frog

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Integrative Zoology 2023年第1期18卷 2-14页

作者： Thomas P.HASTINGS blake r.HOSSACK LeeAnn FISHBACK Jon M.DAVENPOrT Department of Biology Appalachian State UniversityBooneNorth CarolinaUSA U.S.Geological Survey Northern Rocky Mountain Science Centerand Wildlife Biology ProgramW.A.Franke College of Forestry&ConservationUniversity of MontanaMissoulaMontanaUSA Churchill Northern Studies Centre ChurchillManitobaCanada

Species with especially close dependence on the environment to meet physiological requirements,such as ectotherms,are highly susceptible to the impacts of climate *** change is occurring rapidly in the Subarctic and Arctic,but there is limited knowledge on ectotherm physiology in these *** investigated how environmental conditions and habitat characteristics inﬂuence the physiological conditions and habitat use of wood frogs(rana sylvatica)in a Subarctic landscape near Churchill,Manitoba(Canada).We used plaster models to estimate water loss rates and surface body temperatures among different habitat types and at speciﬁc locations used by radio-tracked *** loss(r2=0.67)and surface temperature(r2=0.80)of plaster models was similar to that of live ***-based water loss rates were greater in tundra habitat than in boreal forest and ecotone *** use of wood frogs was strongly tied with available surface moisture and decreased water loss rates that were observed with plaster *** conditions,such as wind speed and ground tem-perature,explained 58%and 91%of the variation in water balance and temperature of plaster *** physiological conditions may be challenging for semi-aquatic ectotherms in environments vulnerable to future cli-mate *** ability to predict physiological conditions based on environmental conditions,as demonstrated in our study,can help understand how wildlife will respond to climatic changes.

关键词： Arctic climate change landscape physiology water balance wood frog

Scale-up of biomass conversion using 1-ethyl-3-methylimidazolium acetate as the solvent

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Green Energy & Environment 2019年第4期4卷 432-438页

作者： Ling Liang Jipeng Yan Qian He Tina Luong Todd r.Pray blake A.Simmons Ning Sun Advanced Biofuels and Bioproducts Process Development Unit Lawrence Berkeley National LaboratoryEmeryvilleCA94608USA Joint BioEnergy Institute Lawrence Berkeley National LaboratoryEmeryvilleCA94608USA

This scale-up study demonstrated the feasibility of an ionic liquid(IL)pretreatment process at 40 kg scale,using the IL 1-ethyl-3-methylimidazolium acetate([C2C1Im][OAc])as the *** pretreatment was followed by enzymatic hydrolysis through which the process efficiency for biomass conversion to monomeric sugars was *** results show that 43 wt%of switchgrass was dissolved in IL after 2 h of pretreatment at 160℃ with 15 wt%solid loading.A 120 h enzymatic hydrolysis of the pretreated switchgrass results in 96%glucan and 98%xylan conversion.[C2C1Im][OAc]pretreatment has been successfully scaled up to 40 kg with improved sugar titers and yields relative to bench scale(6 kg).The mass flow of the overall process was established and the major scale-up challenges of the process were identified.

关键词： Ionic liquid 1-Ethyl-3-methylimidazolium acetate Pretreatment Scale up Enzyme

EXISTENCE AND STABILITY OF VISCOUS SHOCK PrOFILES FOr 2-D ISENTrOPIC MHD WITH INFINITE ELECTrICAL rESISTIVITY

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Acta Mathematica Scientia 2010年第2期30卷 447-498页

作者： blake Barker Olivier Lafitte Kevin Zumbrun Department of Mathematics Indiana University LAGA Institut GalileeUniversite Paris 1393 430 Villetaneuse and CEA SaclayDM2S/DIR91 191 Gif sur Yvette CedexFrance

For the two-dimensional Navier-Stokes equations of isentropic magnetohydrodynamics （MHD） with γ-law gas equation of state, γ≥ 1, and infinite electrical resistivity, we carry out a global analysis categorizing all possible viscous shock profiles. Precisely, we show that the phase portrait of the traveling-wave ODE generically consists of either two rest points connected by a viscous Lax profile, or else four rest points, two saddles and two nodes. In the latter configuration, which rest points are connected by profiles depends on the ratio of viscosities, and can involve Lax, overcompressive, or undercompressive shock profiles. Considered as three-dimensional solutions, undercompressive shocks axe Lax-type （Alfven） waves. For the monatomic and diatomic cases γ= 5/3 and γ=7/5, with standard viscosity ratio for a nonmagnetic gas, we find numerically that the the nodes are connected by a family of overcompressive profiles bounded by Lax profiles connecting saddles to nodes, with no undercompressive shocks occurring. We carry out a systematic numerical Evans function analysis indicating that all of these two-dimensional shock pro- files are linearly and nonlinearly stable, both with respect to two- and three-dimensional perturbations. For the same gas constants, but different viscosity ratios, we investigate also cases for which undercompressive shocks appear; these are seen numerically to be stable as well, both with respect to two-dimensional and （in the neutral sense of convergence to nearby riemann solutions） three-dimensional perturbations.

关键词： stability of viscous shock waves Evans function magnetohydrodynamics

3D printed nerve guidance channels: computer-aided control of geometry, physical cues, biological supplements and gradients

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Neural regeneration research 2016年第10期11卷 1568-1569页

作者： blake N.Johnson Xiaofeng Jia Department of Industrial and Systems Engineering School of Neuroscience Virginia Tech Department of Neurosurgery Orthopaedics Anatomy and Neurobiology University of Maryland School of Medicine Department of Biomedical Engineering Anesthesiology and Critical Care Medicine Johns Hopkins University School of Medicine

Nerve guidance channels for peripheral nerve injury： Over the past decade, nerve guidance channels （NGCs） have emerged as a promising technology for regenerating gap injuries in peripheral nerves. Nerve gap injuries resulting from neurodegeneration and trauma, such as car accidents and battlefield wounds, affect hun- dreds of thousands of people annually. Motivated by suboptimal results obtained with the current gold standard of autologous grafting （i.e., autografts）, various commercially available NGCs composed of synthetic and biomaterials are now alternatively available （Jia et al., 2014; Jones et al., 2016）.

关键词： NGC physical cues printed nerve guidance channels biological supplements and gradients computer-aided control of geometry

Testing whether adrenal steroids mediate phenotypic and physiologic effects of elevated salinity on larval tiger salamanders

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Integrative Zoology 2023年第1期18卷 27-44页

作者： Brian J.TOrNABENE Erica J.CrESPI Creagh W.BrEUNEr.blake r.HOSSACK Wildlife Biology Program W.A.Franke College of Forestry&ConservationUniversity of MontanaMissoulaMontanaUSA School of Biological Sciences Center for Reproductive SciencesWashington State UniversityPullmanWashingtonUSA U.S.Geological Survey Northern Rocky Mountain Science CenterMissoulaMontanaUSA

Salinity(sodium chloride,NaCl)from anthropogenic sources is a persistent contaminant that negatively affects freshwater *** can be susceptible to salinity,but some species are innately or adaptively *** mechanisms mediating tolerance to salinity are still unclear,but changes in osmoregulatory hor-mones such as corticosterone(COrT)and aldosterone(ALDO)are prime *** exposed larval barred tiger salamanders(Ambystoma mavortium)to environmentally relevant NaCl treatments(r 24 days to test effects on growth,survival,and waterborne COrT *** those sampled,we also quantiﬁed waterborne ALDO from a *** a glucocorticoid antagonist(rU486),we also experimentally suppressed COrT signaling of some larvae to determine if COrT mediates effects of *** were no strong differ-ences in survival among salinity treatments,but salinity reduced dry mass,snout–vent length,and body condition while increasing water content of *** survival and sublethal effects demonstrated that salamanders were physiologically challenged but could tolerate the experimental *** signaling did not attenuate sublethal effects of *** and stress-induced(after an acute stressor,shaking)COrT were not inﬂu-enced by *** was correlated with baseline COrT,suggesting it could be difﬁcult to decouple the roles of COrT and *** studies comparing ALDO and COrT responses of adaptively tolerant and previously unexposed populations could be beneﬁcial to understand the roles of these hormones in tolerance to ***-ertheless,our study enhances our understanding of the roles of corticosteroid hormones in mediating effects of a prominent anthropogenic stressor.

关键词： caudate conservation physiology glucocorticoids sodium chloride tolerance

Assessment of buckling-restrained braced frame reliability using an experimental limit-state model and stochastic dynamic analysis

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Earthquake Engineering and Engineering Vibration 2009年第3期8卷 373-385页

作者： blake M.Andrews Junho Song Larry A.Fahnestock Wiss JanneyElstner AssociatesIncNorthbrookIllinoisUSA Department of Civil and Environmental Engineering University of Illinois at Urbana-ChampaignUrbanaIllinoisUSA

Buckling-restrained braces （BrBs） have recently become popular in the United States for use as primary members of seismic lateral-force-resisting systems. A BrB is a steel brace that does not buckle in compression but instead yields in both tension and compression. Although design guidelines for BrB applications have been developed, systematic procedures for assessing performance and quantifying reliability are still needed. This paper presents an analytical framework for assessing buckling-restrained braced frame （BrBF） reliability when subjected to seismic loads. This framework efficiently quantifies the risk of BrB failure due to low-cycle fatigue fracture of the BrB core. The procedure includes a series of components that：（1） quantify BrB demand in terms of BrB core deformation histories generated through stochastic dynamic analyses; （2） quantify the limit-state of a BrB in terms of its remaining cumulative plastic ductility capacity based on an experimental database; and （3） evaluate the probability of BrB failure, given the quantified demand and capacity, through structural reliability analyses. Parametric studies were conducted to investigate the effects of the seismic load, and characteristics of the BrB and BrBF on the probability of brace failure. In addition, fragility curves （i.e., conditional probabilities of brace failure given ground shaking intensity parameters） were created by the proposed framework. While the framework presented in this paper is applied to the assessment of BrBFs, the modular nature of the framework components allows for application to other structural components and systems.

关键词： risk and reliability analysis buckling-restrained brace stochastic dynamic analysis first-order reliability method cumulative plastic ductility capacity

On the exoneration of Dr. William H. Stewart: debunking an urban legend

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Infectious Diseases of Poverty 2013年第1期2卷 17-21页

作者： Brad Spellberg Bonnie Taylor.blake Los Angeles Biomedical research Institute at Harbor-University of California at Los Angeles(UCLA)Medical Center TorranceCAUSA The David Geffen School of Medicine at UCLA Los AngelesCAUSA University of North Carolina School of Medicine Chapel Hill WilmingtonNCUSA

Background:It is one of the most infamous quotes in the history of biomedicine:“It is time to close the book on infectious diseases,and declare the war against pestilence won.”Long attributed to the United States Surgeon General,*** ***(1965-1969),the statement is frequently used as a foil by scientific and lay authors to underscore the ever-increasing problems of antibiotic-resistant and emerging ***,the primary source for the quote has never been ***:We undertook a comprehensive search of multiple databases encompassing medical literature,news articles,and congressional records to attempt to identify sources for the ***:No source of the quote was ***,a trail of source documents was identified that clearly serves as the basis for subsequent,incorrect attribution of the quote to *** multiple source documents,*** made statements to the opposite effect,clearly recognizing that infectious diseases had not been *** urban legend was created by a combination of lack of primary witnesses to the originating speech,misunderstanding of points made by *** in the speech,and increasing societal concern about emerging and re-emerging infectious ***:Attribution to *** of a belief that it was time to close the book on infectious diseases is an urban legend;he never made any such *** other verifiable sources,however,confirm that other people in academia adopted this *** should no longer be cited in this regard,and should be replaced with verifiable sources.

关键词： William H.Stewart Urban legend History of antibiotics Antibiotic development Antibiotic crisis Public policy