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11.
The collision processes responsible for populating and de-populating upper and lower levels of the cw He-Hg ion laser are investigated using flowing afterglow techniques. It is shown that the superior performance of the laser at 6150 Å compared to that at 7945 Å is not due to a difference in excitation mechanism — both are excited by charge transfer from He+ — but instead reflects a greater effectiveness of second kind collisions of electrons in depopulating the 7p2P upper level of the 7945 Å transition. The charge transfer, excitation rate constants for several Hg II levels are compared, and values for the rate constant for the electron collision de-excitation process are deduced. 相似文献
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14.
As much as 3 W of average power at 1064 nm from a diode-pumped Nd:YAG laser, Q switched at 4 kHz, was used to pump an external-resonator, crystalline Ba(NO3)2 Raman laser generating a maximum of 1.3-W output at the first Stokes wavelength of 1197 nm. The slope efficiency was 63% with respect to the fundamental power incident on the Ba(NO3)2 crystal. A reduction in the beam quality of the Stokes output from M2 approximately 1.4 at lower Stokes powers to M2 approximately 3.4 at higher powers is attributed to thermal loading of the Raman-active crystal. 相似文献
15.
Piper DJ Barbante GJ Brack N Pigram PJ Hogan CF 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):474-480
The electrodeposition of the electrochemiluminescent (ECL) ruthenium complex, bis(2,2'-bipyridyl)(4'-(4-aminophenyl)-2,2'-bipyridyl)ruthenium(II), [Ru(bpy)(2)(apb)](2+), via the in situ formation of a diazonium species from aqueous media is reported. Surface characterization undertaken using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) determined that the layer is bound to the substrate via azo bonding. The layer displays good ECL activity and is stable over a long period of time. The excellent potential of this system for ECL sensing applications is demonstrated using the well-known ECL coreactant 2-(dibutylamino)ethanol (DBAE) as a model analyte, which can be detected to a level of 10 nM with a linear range between 10(-8) and 10(-4) M. 相似文献
16.
Floyd WC Klemm PJ Smiles DE Kohlgruber AC Pierre VC Mynar JL Fréchet JM Raymond KN 《Journal of the American Chemical Society》2011,133(8):2390-2393
One essential requirement for more sensitive gadolinium-based MRI contrast agents is to slow the molecular tumbling of the gadolinium(III) ion, which increases the gadolinium's relaxivity (i.e., its ability to speed up the NMR relaxation of nearby water molecules). One route to this is through conjugation to high-molecular-weight polymers such as dendrimers. In this work, amine-functionalized TREN-bis(1,2-HOPO)-TAM-ethylamine and TREN-bis(1-Me-3,2-HOPO)-TAM-ethylamine ligands have been synthesized and attached to biocompatible 40 kDa esteramide (EA)- and poly-l-lysine (PLL)-based dendrimers capable of binding up to eight gadolinium complexes. These conjugates have T(1) relaxivities of up to 38.14 ± 0.02 mM(-1) s(-1) per gadolinium at 37 °C, corresponding to relaxivities of up to 228 mM(-1) s(-1) per dendrimer molecule. This relaxivity expressed on a "per Gd" basis is several times that of the small-molecule complexes and an order of magnitude higher than that of current commercial agents. Because of their high performance and low toxicity, these macromolecules may constitute an attractive complement to currently available gadolinium(III)-based contrast agents. 相似文献
17.
We have investigated the output behaviour of a low temperature HyBrID-type copper laser operating with a flowing Ne–HCl reactive
gas mixture. 15.5 W of average power was observed from a 19 mm bore device at 23 kHz PRF corresponding to a specific output
power of 78 mW/cm3. The output power was 20–30% lower than that of the same device operating with an Ne–HBr mixture; however,
it markedly exceeds the output of similar sized elemental copper vapour lasers (with or without hydrogen additive).
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
M. D. Ainsworth D. J. W. Brown D. W. Coutts J. A. Piper 《Optical and Quantum Electronics》1991,23(4):S539-S548
The characteristics of high repetition rate CVL devices incorporating passive external heating have been investigated. Pre-heating of the CVL plasma tube using external heating has been shown to significantly reduce CVL warm-up time, while supplementary heating of the CVL plasma tube using external heating allows efficient CVL operation with reduced discharge power input without any degradation in output power. 相似文献
19.
J. Papenberg W. Piper W. Kalke und U. Knobloch 《Fresenius' Journal of Analytical Chemistry》1970,252(2-3):174-178
Zusammenfassung Nach Sepharose 2 B Gelfiltration nimmt die Mobilität der Lipoproteinfraktionen VLDL, LDL und HDL auf Agarose-Gel zu. Albumin macht diesen Effekt rückgängig. Die Möglichkeit der Spontanhydrolyse der Triglyceride der Lipoproteinfraktionen mit Zunahme der freien Fettsäuren und damit auch der elektrischen Ladung wird diskutiert. Der Albumineffekt beruht dann auf einer Bindung dieser freien Fettsäuren.
Abkürzungen VLDL Very Low Density Lipoprotein - LDL Low Density Lipoprotein - HDL High Density Lipoprotein Teilweise unterstützt von der Deutschen Forschungsgemeinschaft. 相似文献
Effect of albumin on the electrophoretic mobility of human serum lipoproteins on agarose gel
The electrophoretic mobility of the VLDL, LDL and HDL fractions increases on agarose gel after Sepharose 2 B gel filtration. This effect is broken of by albumin. The possibility of spontaneous hydrolysis of the triglycerides of the lipoproteins with a successive increase of the free fatty acid content and electric charge is discussed. The albumin effect is based on the binding of these free fatty acids.
Abkürzungen VLDL Very Low Density Lipoprotein - LDL Low Density Lipoprotein - HDL High Density Lipoprotein Teilweise unterstützt von der Deutschen Forschungsgemeinschaft. 相似文献
20.
Directly written monolithic waveguide laser incorporating a distributed feedback waveguide-Bragg grating 总被引:2,自引:0,他引:2
We report the fabrication and performance of the first C-band directly written monolithic waveguide laser (WGL). The WGL device was created in an erbium- and ytterbium-doped phosphate glass host and consisted of an optical waveguide that included a distributed feedback Bragg grating structure. The femtosecond laser direct-write technique was used to create both the waveguide and the waveguide-Bragg grating simultaneously and in a single processing step. The waveguide laser was optically pumped at approximately 980 nm and lased at 1,537 nm with a bandwidth of less than 4 pm. 相似文献