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101.
Bennett N. Walker Jessica A. Stolee Deanna L. Pickel Scott T. Retterer Akos Vertes 《Applied Physics A: Materials Science & Processing》2010,101(3):539-544
Experimental assessment of the thermal load induced by fast laser pulses on micro- and nanostructures through IR imaging is
currently too slow and lacks the spatial resolution to be useful. In this paper, we introduce a method based on measuring
the laser-induced yields of ions to compare the thermal loads on nanofabricated silicon structures, when exposed to nanosecond
laser pulses. The laser fluences at which the ion yields of, for example, sodiated and potassiated peptides ions are equal
for two different structures correspond to equivalent thermal loads. Using alkalinated peptides is a convenient choice because
the corresponding ion intensities are easily measured up to the melting point of silicon. As an example, we compare the nanosecond
laser heating of silicon nanopost arrays with diverse post diameters and periodicities. Assessment of the thermal load through
ion yield measurements can also be used to verify model assumptions for heat transport regimes in nanostructures. 相似文献
102.
New use of BCG for recombinant vaccines 总被引:147,自引:0,他引:147
C K Stover V F de la Cruz T R Fuerst J E Burlein L A Benson L T Bennett G P Bansal J F Young M H Lee G F Hatfull 《Nature》1991,351(6326):456-460
BCG, a live attenuated tubercle bacillus, is the most widely used vaccine in the world and is also a useful vaccine vehicle for delivering protective antigens of multiple pathogens. Extrachromosomal and integrative expression vectors carrying the regulatory sequences for major BCG heat-shock proteins have been developed to allow expression of foreign antigens in BCG. These recombinant BCG strains can elicit long-lasting humoral and cellular immune responses to foreign antigens in mice. 相似文献
103.
Joan Orobitg Carlos Pé rez 《Transactions of the American Mathematical Society》2002,354(5):2013-2033
We study an analogue of the classical theory of weights in without assuming that the underlying measure is doubling. Then, we obtain weighted norm inequalities for the (centered) Hardy-Littlewood maximal function and corresponding weighted estimates for nonclassical Calderón-Zygmund operators. We also consider commutators of those Calderón- Zygmund operators with bounded mean oscillation functions (), extending the main result from R. Coifman, R. Rochberg, and G. Weiss, Factorization theorems for Hardy spaces in several variables, Ann. of Math. 103 (1976), 611-635. Finally, we study self-improving properties of Poincaré-B.M.O. type inequalities within this context; more precisely, we show that if is a locally integrable function satisfying for all cubes , then it is possible to deduce a higher integrability result for , assuming a certain simple geometric condition on the functional . 相似文献
104.
Jonathan M. Bennett 《Transactions of the American Mathematical Society》2002,354(12):4871-4892
We study certain Hilbert transforms and maximal functions along variable flat curves in the plane. We obtain their boundedness by considering the oscillatory singular integrals which arise from an application of a partial Fourier transform.
105.
Band gaps and defect modes in periodically structured waveguides 总被引:2,自引:0,他引:2
Munday JN Bennett CB Robertson WM 《The Journal of the Acoustical Society of America》2002,112(4):1353-1358
This work examines a simple one-dimensional acoustic band gap system made from a diameter-modulated waveguide. Experimental and theoretical results are presented on perfectly periodic waveguide arrays showing the presence of band gaps--frequency intervals in which the transmission of sound is forbidden. The introduction of defects in the perfect periodicity leads to narrow frequency transmission bands--defect states--within the forbidden band gaps. The circular cross-section waveguide system is straightforward to simulate theoretically and experimental results demonstrate good agreement with theory. The experimental transmission of the periodic waveguide arrays is measured using an impulse response technique. 相似文献
106.
Tercero J Diaz C Ribas J Mahía J Maestro M 《Chemical communications (Cambridge, England)》2002,(4):364-365
The new heterodinuclear complex [Cu(Me2oxpn)Ni(NO2)(tmen)](ClO4), that exhibits strong antiferromagnetic intramolecular coupling between CuII and NiII ions (ferrimagnetic behavior), shows ferromagnetic ordering at low temperature, due likely to a small canting phenomenon; it is one of the very few compounds made from isolated molecules that lead to cooperative magnetic behavior. 相似文献
107.
Bennett IM Farfano HM Bogani F Primak A Liddell PA Otero L Sereno L Silber JJ Moore AL Moore TA Gust D 《Nature》2002,420(6914):398-401
Transport of calcium ions across membranes and against a thermodynamic gradient is essential to many biological processes, including muscle contraction, the citric acid cycle, glycogen metabolism, release of neurotransmitters, vision, biological signal transduction and immune response. Synthetic systems that transport metal ions across lipid or liquid membranes are well known, and in some cases light has been used to facilitate transport. Typically, a carrier molecule located in a symmetric membrane binds the ion from aqueous solution on one side and releases it on the other. The thermodynamic driving force is provided by an ion concentration difference between the two aqueous solutions, coupling to such a gradient in an auxiliary species, or photomodulation of the carrier by an asymmetric photon flux. Here we report a different approach, in which active transport is driven not by concentration gradients, but by light-induced electron transfer in a photoactive molecule that is asymmetrically disposed across a lipid bilayer. The system comprises a synthetic, light-driven transmembrane Ca2+ pump based on a redox-sensitive, lipophilic Ca2+-binding shuttle molecule whose function is powered by an intramembrane artificial photosynthetic reaction centre. The resulting structure transports calcium ions across the bilayer of a liposome to develop both a calcium ion concentration gradient and a membrane potential, expanding Mitchell's concept of a redox loop mechanism for protons to include divalent cations. Although the quantum yield is relatively low (approximately 1 per cent), the Ca2+ electrochemical potential developed is significant. 相似文献
108.
Bennett GR Cuneo ME Vesey RA Porter JL Adams RG Aragon RA Caird JA Landen OL Rambo PK Rovang DC Ruggles LE Simpson WW Smith IC Wenger DF 《Physical review letters》2002,89(24):245002
An inertial-confinement-fusion (ICF) concept using two 60-MA Z pinches to drive a cylindrical hohlraum to 220 eV has been recently proposed. The first capsule implosions relevant to this concept have been performed at the same physical scale with a lower 20-MA current, yielding a 70+/-5 eV capsule drive. The capsule shell shape implies a polar radiation symmetry, the first high-accuracy measurement of this type in a pulsed-power-driven ICF configuration, within a factor of 1.6-4 of that required for scaling to ignition. The convergence ratio of 14-21 is to date the highest in any pulsed-power ICF system. 相似文献
109.
In the interaction of molecules with light endowed with orbital angular momentum, an exchange of orbital angular momentum in an electric dipole transition occurs only between the light and the center of mass motion; i.e., internal "electronic-type" motion does not participate in any exchange of orbital angular momentum in a dipole transition. A quadrupole transition is the lowest electric multipolar process in which an exchange of orbital angular momentum can occur between the light, the internal motion, and the center of mass motion. This rules out experiments seeking to observe exchange of orbital angular momentum between light beams and the internal motion in electric dipole transitions. 相似文献
110.
[formula: see text] The reactions of glycals with ceric(IV) ammonium nitrate and sodium iodide in the presence of acetic acid provides 2-deoxy-2-iodo-alpha-mannopyranosyl acetates with good stereoselectivity. In the majority of the cases examined, the selectivity was considerably better than that from reactions using N-iodosuccinimide and HOAc. 相似文献