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The properties of passive Q-switched short-cavity dye lasers (SCDL) and passive Q-switched distributed-feedback dye lasers (DFDL) are investigated theoretically by using rate-equation models. The calculations, in agreement with experimental results, predict a significant decrease of the pulse energy fluctuation and the pulse duration of both the SCDL and DFDL, when passive Q-switching is used. 相似文献
3.
We study the functionb(n, d), the maximal number of atoms defined byn d-dimensional boxes, i.e. parallelopipeds in thed-dimensional Euclidean space with sides parallel to the coordinate axes.
We characterize extremal interval families definingb(n, 1)=2n-1 atoms and we show thatb(n, 2)=2n
2-6n+7.
We prove that for everyd,
exists and
.
Moreover, we obtainb*(3)=8/9. 相似文献
4.
本文研究了在-170℃到+20℃温度范围内,Sb-Cs光阶极的光效应对温度的依赖关系。在极限波长附近,当温度下降时,发现灵敏度单纯地下降。在短波的地方,灵敏度在一个宽的温度范围内与温度无关;只有到极低温度时,灵敏度才很快下降。 相似文献
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Self-decomposition of the nickel(III) doubly deprotonated peptide complex of Gly2HisGly occurs by base-assisted oxidation of the peptide. At < or =p[H+] 7.0, the major pathway is a four-electron oxidation (via 4 Ni(III) complexes) at the alpha carbon of the N-terminal glycyl residue. The product of this oxidation is oxamylglycylhistidylglycine, which hydrolyzes to yield ammonia and oxalylglycylhistidylglycine. Both of these peptide products decompose to give isocyanatoacetylhistidylglycine. A small amount (2%) of oxidative decarboxylation also is observed. In another major pathway above p[H+] 7.0, two Ni(III)-peptide complexes coordinate via an oxo bridge in the axial positions to form a reactive dimer species. This dimer generates two Ni(II)-peptide radical intermediates that cross-link at the alpha carbons of the N-terminal glycyl residues. In 0.13 mM Ni(III)-peptide at p[H+] 10.3, this pathway accounts for 60% of the reaction. The cross-linked peptide is subject to oxidation via atmospheric O2, where the 2,3-diaminobutanedioic acid is converted to a 2,3-diaminobutenedioic acid. The products observed at
相似文献
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The concept of a localk-coloring of a graphG is introduced and the corresponding localk-Ramsey numberr
loc
k
(G) is considered. A localk-coloring ofG is a coloring of its edges in such a way that the edges incident to any vertex ofG are colored with at mostk colors. The numberr
loc
k
(G) is the minimumm for whichK
m
contains a monochromatic copy ofG for every localk-coloring ofK
m
. The numberr
loc
k
(G) is a natural generalization of the usual Ramsey numberr
k
(G) defined for usualk-colorings. The results reflect the relationship betweenr
k
(G) andr
loc
k
(G) for certain classes of graphs.This research was done while under an IREX grant. 相似文献
8.
The doubly-deprotonated Ni(III) complex of Gly(2)Ha (where Ha is histamine) undergoes base-assisted oxidative self-decomposition of the peptide. At = p[H(+)] 7.0, a major pathway is a two-electron oxidation at the alpha-carbon of the N-terminal glycyl residue. Major products (up to 73%) of this two-electron oxidation are glyoxylglycylhistamine and ammonia. Glyoxylglycylhistamine will decay to give isocyanatoacetylhistamine and formaldehyde. Two-electron oxidations of the second glycyl and histamine residues occur as minor pathways (12% of the total possible reaction). Above p[H(+)] 8.5, two Ni(III)-peptide complexes form an oxo bridge in the axial positions to give a reactive dimer species. This proximity allows the resulting Ni(II)-peptide radical intermediates to undergo peptide-peptide cross-linking at the N-terminal glycyl residues. The products found below p[H(+)] 7.0 are observed above p[H(+)] 8.5 as well, although in lower yields. In contrast to this work, Ni(III)(H(-2)Gly(2)HisGly) undergoes a four-electron oxidation at the N-terminal glycyl residue. Oxidation at the internal glycyl and histidyl residues are not observed. The reactivity of Ni(III)(H(-2)Gly(2)Ha)(+) is also different than Cu(III)(H(-2)Gly(2)Ha)(+), which undergoes a two-electron oxidation at the histamine group with no peptide-peptide cross-linking in basic solution. 相似文献
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G. Molnár ZS. Révay Á. Veres A. Simonits H. Rausch 《Journal of Radioanalytical and Nuclear Chemistry》1993,167(1):133-137
The restart of the recently upgraded research reactor in Budapest is foreseen at the end of this year. A number of fast, thermal and cold neutron beams will serve for research, industrial and educational activities. One of the cold neutron guide end positions will be utilized for neutron capture prompt gamma-ray activation analysis (PGAA). Further development of the PGAA method as well as new applications in environmental research, biology and medicine are planned. 相似文献
10.
OG Khvostenko ZS Yarullina NM Shishlov VE Rusin 《Rapid communications in mass spectrometry : RCM》1999,13(12):1091-1097
A correlation between the energies of electronic singlet transitions in benzodiazepines and their biological activity, which was revealed earlier by means of negative ion mass spectrometry with resonance electron capture, has been verified with a UV absorption spectroscopy investigation. Also, it has been noted that the energies of electronic singlet transitions in benzodiazepines are close in value to the ionization energies of atoms Cs, Rb, K, Na, Li and Tl, the cations of which are known to play an important role in nerve cell excitation processes. Copyright 1999 John Wiley & Sons, Ltd. 相似文献