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981.
982.
Dale Newbury David Wollman Sae Woo Nam Gene Hilton Kent Irwin John Small John Martinis 《Mikrochimica acta》2002,138(3-4):265-274
Analytical X-ray spectrometry for electron beam instruments has advanced significantly with the development of the microcalorimeter
energy dispersive X-ray spectrometer (μcal EDS). The μcal EDS operates by measuring the temperature rise when a single photon
is absorbed in a metal target. A cryoelectronic circuit with electrothermal feedback and a superconducting transition edge
sensor serves as the thermometer. Spectral resolution approaching 4.5 eV for high energy photons (6000 eV) and 2 eV for low
energy photons below 2000 eV has been demonstrated in energy dispersive operation across a photon energy range from 250 eV
to 8 keV. Spectra of a variety of materials demonstrate the power of the μcal EDS to solve practical problems while operating
on a scanning electron microscope platform. 相似文献
983.
A truly miscible ternary miscible blend consisting of poly(?‐caprolactone) (PCL), poly(phenyl methacrylate), and poly(benzyl methacrylate) (PBzMA) was discovered. The three‐polymer blend system was completely miscible within the entire composition range at ambient temperature up to about 150 °C, and ternary phase diagrams at increasing temperatures were characterized and interpreted. A ternary‐interaction model based on the modified Flory–Huggins expression was used to describe the phase diagrams with the individual binary interaction strengths. The model fitted well with the experimental‐phase diagram for the ternary blend system at T = 250 °C, where the binary PCL‐PBzMA blend system is on the critical points of phase separation. Interpretation of discrepancy between the model and experimental at other temperatures was handled with an empirical approach. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 747–754, 2002 相似文献
984.
I.D. Jung F.X. Kärtner J. Henkmann G. Zhang U. Keller 《Applied physics. B, Lasers and optics》1997,65(2):307-310
Received: 20 June 1997 相似文献
985.
Jürgen Jung Michael Fricke Gabriele Hampel Jürgen Hesse 《Hyperfine Interactions》1992,68(1-4):275-278
Among the three possible phase structures (bcc, fcc and hep) of iron rich Fe100-cMn c alloys (c Mn <40 at%), the two closed packed structures, fcc and hep, produce poor resolved and similar Mössbauer spectra. Therefore the evaluation of spectra collected on a sample (nominalc Mn =35 at%) with coexisting fcc and hep phases only was possible with the help of the Afans’ev/Tsymbal method of “Mössbauer lines sharpening” introduced recently/1,2,3/. A comparison of the hyperfine field vs. temperature with an FeNi-Invar alloy (c Ni =35 at%) shows a surprising similarity. 相似文献
986.
This paper is the second part of a threefold article, aimed at solving numerically the Poisson problem in three-dimensional
prismatic or axisymmetric domains. In the first part of this series, the Fourier Singular Complement Method was introduced
and analysed, in prismatic domains. In this second part, the FSCM is studied in axisymmetric domains with conical vertices,
whereas, in the third part, implementation issues, numerical tests and comparisons with other methods are carried out. The
method is based on a Fourier expansion in the direction parallel to the reentrant edges of the domain, and on an improved
variant of the Singular Complement Method in the 2D section perpendicular to those edges. Neither refinements near the reentrant
edges or vertices of the domain, nor cut-off functions are required in the computations to achieve an optimal convergence
order in terms of the mesh size and the number of Fourier modes used. 相似文献
987.
This is the first part of a threefold article, aimed at solving numerically the Poisson problem in three-dimensional prismatic
or axisymmetric domains. In this first part, the Fourier Singular Complement Method is introduced and analysed, in prismatic
domains. In the second part, the FSCM is studied in axisymmetric domains with conical vertices, whereas, in the third part,
implementation issues, numerical tests and comparisons with other methods are carried out. The method is based on a Fourier
expansion in the direction parallel to the reentrant edges of the domain, and on an improved variant of the Singular Complement
Method in the 2D section perpendicular to those edges. Neither refinements near the reentrant edges of the domain nor cut-off
functions are required in the computations to achieve an optimal convergence order in terms of the mesh size and the number
of Fourier modes used.
This author was supported in part by the France/Hong Kong Joint Research Scheme.
This author was supported by DGA/DSP-ENSTA 00.60.075.00.470.75.01 Research Programme
This author was fully supported by Hong Kong RGC grants (Project CUHK4048/02P and project 403403). 相似文献
988.
M. Saif Islam G.Y. Jung T. Ha D.R. Stewart Y. Chen S.Y. Wang R. Stanley Williams 《Applied Physics A: Materials Science & Processing》2005,80(6):1385-1389
A technique involving two steps of chemical mechanical polishing (CMP) has been developed to produce ultra-smooth metal surfaces with an RMS roughness better than 0.1 nm. A figure of merit termed degree of smoothness (DOS) is proposed for the purpose of quantifying the extent of smoothness of a polished metal surface. A post CMP metal slurry cleaning solution was used for cleaning Pt slurry for the first time and by applying special techniques, a very high quality clean surface was attained. Applications of the polished Pt electrodes in interfacing molecular switching devices with self-assembled monolayers of molecules have been found to dramatically improve the packing and orientation of the molecular monolayer with a huge improvement in the molecular electronics device yields. These smooth metal surfaces may open doors for new opportunities in future nanoscale devices. PACS 81.05.Bx; 81.16.Rf; 81.65.Ps 相似文献
989.
An efficient and general synthesis of benzopyrans is achieved by ethylenediamine diacetate-catalyzed reactions of resorcinols with α,β-unsaturated aldehydes in moderated yields. As an application of this methodology, biologically interesting confluentin, which was known to have an inhibitory effect on histamine release is synthesized in one step. Also, natural daurichromenic acid, which has highly potent anti-HIV activity, is successfully synthesized in one step. 相似文献
990.
The lamellar types as revealed by the multiple melting peaks and possible mechanisms of ringed spherulites in poly(trimethylene terephthalate) (PTT) were analyzed with differential scanning calorimetry (DSC), optical microscopy, and scanning electron microscopy. Several interesting correlations were found. If PTT is melt‐crystallized in a certain temperature range, it shows multiple melting peaks and rings in PTT. Once rings are formed in the original melt‐crystallized PTT, they do not disappear but persist and become even more apparent upon postcrystallization annealing at higher temperatures. Furthermore, for PTT that is capable of exhibiting ringed spherulites, a temperature range exists where rings do not form. This behavior can be interpreted in relation with the demonstrated thermal behavior in PTT. Reorganization took place upon postcrystallization scanning or annealing to or at higher temperatures. A postulation was proposed and rigorously tested with evidence to correlate the ringed spherulites and melting behavior. Rings in PTT may be related to multiple lamellae in the spherulites. Consequently, if a temperature of crystallization is selected so that there is only one type of lamella in the spherulites, then there should be no rings. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 80–93, 2002 相似文献