41. |
Detection of mercury vapor using resonating microcantilevers |
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Applied Physics Letters,
Volume 66,
Issue 13,
1995,
Page 1695-1697
T. Thundat,
E. A. Wachter,
S. L. Sharp,
R. J. Warmack,
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摘要:
Oscillating silicon nitride microcantilevers coated with a thin gold film have been used to detect mercury vapor in air. Cantilever resonance frequency changes due to surface mass loading as a result of adsorption of mercury vapor. Furthermore, cantilever bending is also altered due to changes in surface stress induced by mercury adsorption on the gold overlayer. Both of these phenomena can be used to quantitatively detect adsorbed vapors with picogram mass resolution. ©1995 American Institute of Physics.
ISSN:0003-6951
DOI:10.1063/1.113896
出版商:AIP
年代:1995
数据来源: AIP
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42. |
Two‐photon excitation 4Pi confocal microscope: Enhanced axial resolution microscope for biological research |
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Applied Physics Letters,
Volume 66,
Issue 13,
1995,
Page 1698-1700
P. E. Ha¨nninen,
S. W. Hell,
J. Salo,
E. Soini,
C. Cremer,
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摘要:
The applicability of two photon excitation 4Pi confocal fluorescence microscopy to biological imaging is demonstrated. We show that 4Pi confocal microscopy in combination with a simple deconvolution algorithm allows axial localization and quantification with 0.14 &mgr;m resolution in a biological sample. The 4Pi‐confocal microscope extends the applicability of far field fluorescence microscopy to high resolution three‐dimensional imaging and quantification of subcellular structures.
ISSN:0003-6951
DOI:10.1063/1.113897
出版商:AIP
年代:1995
数据来源: AIP
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43. |
Dependence of the nematic liquid crystal pretilt angle on the thickness of the orientation layer |
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Applied Physics Letters,
Volume 66,
Issue 13,
1995,
Page 1701-1703
A. L. Alexe‐Ionescu,
R. Barberi,
M. Giocondo,
G. Cnossen,
T. H. van der Donk,
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摘要:
The influence of an isotropic substrate on the anchoring properties of a nematic liquid crystal has been investigated by varying the thickness of a polyimide orientation layer. By invoking the screening effect of the polymer film on the anisotropic van der Waals interactions between the nematic and the solid substrate, the dependence of the pretilt angle on the thickness of the film has been theoretically evaluated. The agreement of the proposed theory with the experimental data is fairly good. ©1995 American Institute of Physics.
ISSN:0003-6951
DOI:10.1063/1.113898
出版商:AIP
年代:1995
数据来源: AIP
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44. |
Preparation of monolithic barium titanate xerogels by sol–gel processing and the dielectric properties of their sintered bodies |
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Applied Physics Letters,
Volume 66,
Issue 13,
1995,
Page 1704-1706
M. Kuwabara,
K. Miki,
S. Takahashi,
H. Shimooka,
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摘要:
Monolithic xerogels of crystalline barium titanate, with dimensions of ∼3 mm thick and ∼6 mm in diameter, have been produced by sol–gel processing using metal alkoxides. An excess amount of water with the H2O/Ba ratio≳100 (for hydrolysis of the barium titanate precursor alkoxides) and aging time≳8 days were necessary to produce the monolithic crystalline xerogels without breaking during drying (at 90 °C). The barium titanate xerogels as‐dried, with a porosity of about 70%, have been found to consist of crystalline grains in the range of 10–20 nm. Firing the xerogels at 1000 °C in air yielded porous barium titanate ceramics with an average grain size around 50 nm and a decreased porosity around 60%. The dielectric constant (&egr;r)–temperature (T) characteristics of these ceramics have been found to be rather flat below 120 °C with a broad peak around this temperature, and those above 120 °C showed a specific behavior of ferroelectric materials described by a Curie–Weiss equation, &egr;r=C/(T–T0), withC≊2×104K andT0≊230 K (−43 °C); although these values are quite different from those of ferroelectric barium titanate. ©1995 American Institute of Physics.
ISSN:0003-6951
DOI:10.1063/1.113899
出版商:AIP
年代:1995
数据来源: AIP
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