In this paper, we propose a new idea for the automatic recognition of domain specific terms. Our idea is based on the statistics between a compound noun and its component single-nouns. More precisely, we focus basically on how many nouns adjoin the noun in question to form compound nouns. We propose several scoring methods based on this idea and experimentally evaluate them on the NTCIR1 TMREC test collection. The results are very promising especially in the low recall area.
In this paper, we propose a new approach to enhance automatic recognition systems for domain-specific terms. The approach is based on the statistics about the relation between a compound noun and its constituents that are simple nouns. More precisely, we focus on how many nouns adjoin the noun in question to form compound nouns. We propose several scoring methods based on this approach and experimentally evaluate them on the NTCIR1 TMREC test collection. The results are very promising, especially in low and high recall.
The chiral ester (S)-1-(4-methylphenyl)ethyl pentafluorobenzoate, (S)-1-OC(O)C 6 F 5 , was prepared and a value of k rac = 8.5 Â 10 À7 s À1 was determined for the rate constant for its racemization to (R)-1-OC(O)C 6 F 5 in 50:50 (v/v) trifluoroethanol-water (I = 0.50, NaClO 4 ). This rate constant is 12 times smaller than k solv = 1.06 Â 10 À5 s À1 for the stepwise solvolysis of 1-OC(O)C 6 F 5 , which shows that inversion of the ion-pair intermediate is a relatively rare event during solvolysis in a largely aqueous solvent, and two times smaller than k iso = 1.6 Â 10 À6 s À1 for degenerate isomerization which exchanges the position of the ester bridging and non-bridging oxygens of 1-OC(O)C 6 F 5 . A simple relationship is derived between the empirical rate constant ratio k rac /k iso and the microscopic rate constants for reaction of the ion-pair intermediate within its solvation shell. Substitution of estimated rate constants for reactions of the 1-(4-methylphenyl)ethyl carbocation-pentafluorobenzoate anion pair into this equation gives k i = 1.5 Â 10 10 s À1 for inversion of the chiral ion pair, which is similar to k Àd = 1.6 Â 10 10 s À1 for its separation to free ions.
A series of five heterogeneous network polymers was prepared from poly(D‐glutamic acid) (PDG) and poly(oxyethylene glycol) (PEG), and their dynamic mechanical properties were studied. The content of PDG was fixed at 60% by weight, and the molecular weight of PEG was changed to obtain networks with various crosslink densities. An increase in the PEG molecular weight from 330 to 880 caused considerable broadening of tan δ and E″ curves, and peak temperatures for tan δ and E″ decreased slightly. Curves of tan δ and E″ for PDG–PEG 4000 (indicating a PEG component of molecular weight 4,000) were much broader and the existence of two peaks was recognized. These findings and x‐ray photographs suggest that PDG–PEG 330, 570, and 880 give films of fairly uniform phase, but that PDG–PEG 1830 and 4000 give films with two‐phase structure. The factors influencing the dynamic mechanical properties in decreasing order of effectiveness are found to be the proportions by weight of PDG and PEG, the compatibility of PDG with PEG, the crosslink density, and the concentration of free carboxyl groups. The infrared spectra of these polymers indicate that at least part of the PDG component retains the α‐helix conformation.
[reaction: see text]. The sum of the rate constants for solvolysis and 18O-scrambling of 4-MeC6H4(13)CH(Me)18OC(O)C6F5 in 50/50 (v/v) trifluoroethanol/water, k(solv) + k(iso) = 1.22 x 10(-5) s(-1), is larger than k(solv) = 1.06 x 10(-5) s(-1) for solvolysis of the unlabeled ester. This shows that the ion pair intermediate undergoes significant internal return. The data give k(-1) = 7 x 10(9) s(-1) for internal return by unimolecular collapse of the ion pair, which is significantly larger than k(Nu) = 5 x 10(8) M(-1) x s(-1) for bimolecular nucleophilic addition of carboxylate anions to 4-MeC6H4CH(Me)+.
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