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101.
We introduce a local coordinate description for the correspondence
between the space of oriented affine lines in Euclidean
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$$ \mathbb{R}^3 $$
" align="middle" border="0">
and the tangent bundle to the 2-sphere. These can be utilised to give
canonical coordinates on surfaces in
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$$ \mathbb{R}^3 $$
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, as we illustrate with a number of explicit examples.Received: 17 December 2002 相似文献
102.
The Kováts retention indices of all 93 acyclic octenes on polydimethylsiloxane and squalane as stationary phases as well as their mass spectra were measured. The means of gas chromatography-mass spectrometry (GC-MS) were used for confirmation of GC identification as well as for mass spectrometric deconvolution of the majority of gas chromatographic unseparated isomeric octene peaks. The distinction between corresponding E and Z acyclic octenes, that is either difficult or even impossible by means of GC-MS, was obtained on the basis of larger temperature coefficients of retention indices for Z isomeric octenes than for corresponding E isomers. The retention data expressed as homomorphy factors were correlated with the degree of branching, position of double bond, and position of alkyl group with respect to the double bond of acyclic octenes, and the structure-retention relationships were formulated. The 81 acyclic octenes were identified in FCC gasoline. 相似文献
103.
A glycosyl acceptor and a glycosyl donor having the N-3-deoxy-L-glycero-tetronic acid side chain already attached have been prepared and used for the synthesis of the di-through to the hexasaccharide that mimic the upsteam terminus of the O-specific polysaccharide of Vibrio cholerae O:1, serotype Inaba. The target tetra- and the hexasaccharide, which were obtained in the form of 5-methoxycarbonylpentyl glycosides, were linked to BSA using squaric acid diester chemistry. The conjugation reactions were monitored by surface enhanced laser desorption ionization-time of flight mass spectrometry (SELDI-TOF MS). This allowed the progression of the conjugation of the synthetic oligosaccharides in a controlled way and termination of the reaction when the desired molar hapten/BSA ratio had been reached, yielding neoglycoconjugates with predetermined carbohydrate/carrier ratios. The ability to monitor the conjugation by the SELDI-TOF MS technique made it possible to prepare, from one hapten in a one-pot reaction, several neoglycoconjugates having different, predetermined carbohydrate/carrier ratios. 相似文献
104.
A pulsed master oscillator fiber power amplifier working in nanosecond range has been developed. An ytterbium-doped double-clad
(large mode area) optical fiber was used as an amplifying medium. Actively Q-switched Nd:YVO laser was used as a seed of light
pulses. The system worked at the repetition rate from 10 kHz to 40 kHz. At the amplifier output, pulses of 10.9 kW peak-power
were achieved. The laser system worked at the slope efficiency of 30%. 相似文献
105.
Xue Song Feng Yang Qua Zhao Hua Wuc Lei Xua Dong Song Zhanga Hui Yuan Gaoa Li Jun Wu a School of Traditional Chinese Medicines Shenyang Pharmaceutical University Shenyang China b School of Pharmaceutical Sciences China Medical University Shenyang China c Pharmacy Department Mudanjiang Medical University Mudanjiang China 《中国化学快报》2009,20(6)
Chemical investigation of Syringa velutina Kom. led to the isolation of two new secoiridoid glucosides. Their structures were identified as 6'-0-(6, 7-dihyrofoliamenthoyl)-8-epi-kingisidic acid (syrveoside A, 1) and 6'-O-menthiafoloyl-8-epi-kingisidic acid (syrveoside B, 2) on the basis of chemical and physicochemical evidence. 相似文献
106.
Two non-linear azide containing heteronuclear complexes: crystal structure and thermal decomposition
S. Öz R. Kurtaran C. Arıcı Ü. Ergun F. N. Dinçer Kaya K. C. Emregül O. Atakol D. Ülkü 《Journal of Thermal Analysis and Calorimetry》2010,99(1):363-368
Bis-N,N′(salicylidene)-2,2′-dimethyl-1,3-propanediamine (LDMH2) has a high tendency to form polynuclear complexes. Two trinuclear complexes were obtained using this ligand and azide ions;
(CuLDM)2 · Mn(N3)2 · (DMF)2, [(C19H20N2O2Cu)2 · Mn(N3)2 · (C3H7NO)2] and (CuLDM)2 · Cd(N3)2 · (DMF)2, [(C19H20N2O2Cu)2 · Cd(N3)2 · (C3H7NO)2]. The structures were identified with X-ray methods. TG and DSC methods were also employed to these complexes. Studies showed
the (CuLDM)2 · Mn(N3)2 · (DMF)2 and (CuLDM)2 · Cd(N3)2 · (DMF)2 to be non-linear. Also μ-bridges were not encountered for the azide ions but were seen to form between the Cu and other metal
via phenolic oxygens. Thermal analysis showed exothermic degradation of the azide ions destroying the trinuclear structure.
Although azide containing structures show explosive characteristics, this was not observed for the present compounds. 相似文献
107.
Pavel Híc 《Discrete Mathematics》2008,308(16):3704-3705
A graph G is called integral if all the roots of the characteristic polynomial P(G;x) are integers. In the paper the first known integral complete 4-partite graph Kp1,p2,p3,p4, where p1<p2<p3<p4, is constructed. 相似文献
108.
For the reduction of dehydro aminoacids in various media with rhodium complexes containing chiral ligands, a linear correlation of log %S/%R with the solvophobicity parameter Sp has been observed. The decrease in enantioselectivity in water is due to the high interfacial energy of this solvent. 相似文献
109.
Zhi Yang Xiaoli Ma Zhensheng Zhang Herbert W. Roesky Prof. Dr. Dr.h.c. Jörg Magull Arne Ringe 《无机化学与普通化学杂志》2008,634(15):2740-2742
Three heterobimetallic aluminum‐germanium(IV) disulfides are synthesized. The reaction of {LAl[(SLi)2(THF)2]}2 ( 1 ) (L = HC(CMeNAr)2, Ar = 2,6‐iPr2C6H3) with Ph2GeCl2, Me2GeCl2, and GeCl4, respectively, in THF afforded LAl(μ‐S)2GePh2 ( 2 ), LAl(μ‐S)2GeMe2 ( 3 ) and LAl(μ‐S)2Ge(μ‐S)2AlL ( 4 ) in good yields. Compounds 2 , 3 and 4 were investigated by elemental analysis, NMR, EI‐MS and 3 was also characterized by single crystal X‐ray structural analysis. 相似文献
110.
A new macrolide glycoside,cuneataside F was isolated from the n-butanol extract of the stem of Sargentodoxa cuneata. The structure was elucidated on the basis of extensive 1D and 2D NMR as well as HRESI-MS spectroscopic analysis. 相似文献