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81.
Based on analysis of ESR spectra, it is suggested that the initial species formed by electron loss from oxirane (13C) in CFCl3 at 77 K is the ring-closed o(n) radical, rather than the ring-opened “allylic” radical.  相似文献   
82.
Sato  K.  Miyake  T.  Morishita  A.  Matsuta  K.  Minamisono  T.  Tanigaki  M.  Takeda  S.  Mihara  M.  Fukuda  M.  Nojiri  Y.  Minamisono  K.  Fukao  T.  Matsumoto  Y.  Ohtsubo  T.  Fukuda  S.  Momota  S.  Yoshida  K.  Ozawa  A.  Kobayashi  T.  Tanihata  I.  Sagawa  H.  Kitagawa  H.  Krebs  Gray F.  Alonso  Jose R.  Symons  T. James M. 《Hyperfine Interactions》1999,120(1-8):661-665
The electric quadrupole interaction of 19O(Iπ=(5/2)+, T1/2=27.0 s) in TiO2 single crystal was studied in detail by means of the β-NQR to determine the electric quadrupole moments Q of short-lived β-emitting nuclei 19O and 13O(Iπ=(3/2)-, T1/2=8.6 ms). Two implantation sites were found for the implanted O nucleus and the quadrupole coupling constants of 19O at these sites were determined. We observed FT-NMR of the enriched stable isotope 17O in TiO2 and obtained the electric field gradient (EFG) at the oxygen substitutional site. With this knowledge, we have determined Q(13O)=11.0 ± 1.3 mb and Q(19O)=3.7 ± 0.4 mb. The present results are compared with the theoretical values calculated by the shell model code, OXBASH and by the Hartree–Fock calculation with the realistic potential. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
83.
Matsuta  K.  Minamisono  T.  Tanigaki  M.  Onishi  T.  Fukuda  M.  Mihara  M.  Akai  H.  Sasaki  M.  Yamaguchi  T.  Miyake  T.  Sato  K.  Minamisono  K.  Ha  C.  Tanaka  K.  Kidera  K.  Morishita  A.  Kaminaka  S.  Tsubota  T.  Sumikama  T.  Kitagawa  A.  Torikoshi  M.  Kanazawa  M.  Nishio  T.  Koda  S.  Ohtsubo  T.  Nojiri  Y.  Momota  S.  Hanna  S.S.  Alonso  J.R.  Krebs  G.F.  Symons  T.J.M. 《Hyperfine Interactions》1999,120(1-8):719-723
The Knight shifts K for short-lived β emitters 12N and 27Si implanted in Pt have been measured by means of β-NMR technique. The results were K(12N in Pt)= +(5.8 ± 2.1)× 10-4 and K(27Si in Pt)= +(1.4 ± 0.8)× 10-3. The spin–lattice relaxation time T1 was measured for 12N in Pt. The result was T1(12N in Pt, T=300 K)= 66 ± 8 ms, thus, T1T= 20 ± 2 Ks. The present Knight shifts are in good agreement with the KKR band structure calculation with local lattice relaxation determined theoretically. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
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Summary : Injectable biodegradable hydrogels have been developed to determine the efficacy of biomaterials for the treatment of periodontitis through control delivery of bone-healing bioactives. The hydrogels were prepared from the PEG-ylated macromer of Boltorn™ H20 (BH20) and an acrylated triblock copolymer of polylactide-polyethylene glycol (2k)-polylactide (PLA) in various molar ratios using ammonium persulfate and sodium ascorbate as a free radical initiating system. Preliminary investigations involving the synthesis of PLA hydrogels with different PLLA block lengths were studied in order to determine the swelling ratios and degradation rates of the biodegradable component of the hydrogels prior to copolymerization with BH20. The swelling and degradation studies of PLA with PEG diacrylate (FW 700) hydrogels were established in phosphate buffered saline (PBS) at 37 °C, pH 7.4 and in water (pH ∼5.5). They have been shown to have low swelling ratios (Qmax = 4.4 to 3.6) and degradation times of 20–30 days. The swelling and degradation parameters were found to be dependent on the molar ratio of the PEG diacrylate to PLA in the copolymer.  相似文献   
88.
The Kagome Double-Layer Grid (KDLG) is a sandwich-like structure, based on the planar Kagome pattern, which has properties that make it attractive for application as a morphing material. In order to understand the passive and active properties of the KDLG with rigid joints, an analysis is made of the determinacy of the pin-jointed version. The number of internal mechanisms and states of self-stress of the finite pin-jointed structure are calculated as a function of the size of the structure. A statically and kinematically determinate version is obtained by relocating the internal nodes and by prescribing a set of patch bars around the periphery. The actuation performance of the rigid-jointed version is then explored theoretically by replacing a single bar in the structure by an actuator. The resistance to actuation is determined in terms of the stiffness and the allowable actuation strain as dictated by yield and buckling. The paper concludes with the optimal design of a double-layer grid to maximise actuation performance.  相似文献   
89.
This paper characterises completely the circumstances in which maximum likelihood estimation of the factor model is feasible when the sample covariance matrix is rank deficient. This situation will arise when the number of variables exceeds the number of observations.  相似文献   
90.
A representative series is studies of organic radicals formed by the effective addition of muonium to the carbonyl oxygen atom of aldehydes, ketones, esters and amides. Low values of the muonelectron hyperfine coupling are measured which are particularly sensitive to radical structure and dynamics. The systematics of these values are discussed in terms of the opposing contributions of conjugation and hyperconjugation.  相似文献   
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