The slow tumbling motion of a spin labelled SBS block copolymer was investi-gated by the saturation transfer ESR (ST-ESR). Motions pertaining to the rota-tional correlation time from 10~(-6) to 10~(-5)S were observed in the temperature rangefrom -70℃ to -20℃, and thereby the parameter T_R ascertained by ESR.

The contributions of dipole—dipole relaxation and Spin—rotation relaxatiot have been separated. The molecular reorientation correlation time, isotropic rotation diffusion constant and the barriers of the internal rotation of methyl have been calculated. The whole molecle motion and internal rotation motion of methyl have been discussed using, these data.

The results show that light chemical crosslinks has, to some extent, an influence on the distribution of correlation time, but no distinct effect on the potential for segmental motion.

Furthermore, the rotational correlation time r, the heights of the upfield EPR lines were found to be linearly correlated with the solvent viscosity η.

The empirical Cole-Cole, Fuoss-KirkwOod distribution models of correlation times, the con-formational jump model proposed by Valeur et al. and the damped orientational diffusion model of polymer local main-chain motion proposed by Skolnick and Yaris were used to fit the experimental 13C-NMR spin-lattice relaxation times (T1) and nuclear Overhauser effect (NOE) data of 1,2-polybutadienes in CDCL3 solution.

The 13C total spin-lattice relaxation times and the NOE factors of N-butyl aniline were measured at two temperatures by means of inversion recovery pulse sequences (180-t-90T). The contributions of each relaxation mechanism were appreciated by calculation, the correlation times re of molecular random movements were deduced, and the dynamic situation of the molecules was discussed

The carbon-13 spin-lattice relaxation times and nuclear overhauser enhancement factors (NOE) fora series of 1, 2-polybutadienes with different configurations of 1,2-units in solution of CDC13 are determined on 200 MHz pulse FT-NMR Spectrometer. Different kinds of model in interpreting the carbon-13 NMR relaxation data including the Cole-Cole, Fuoss-kirkwood distribution mobel of correlation times , the configurational jump model proposed by valeur et. al.

The rotational correlation times and diffusion coefficients of a-CH, in a series of poly (methyl methacrylates) crosslinked with DVB were calculated according to the measured T, values.

We got the similar conclusion when used the denaturalization of heating, we denaturalized the protein in the range of 65°C to 85°C, via the study of ESR found when temperature increased τ_c decreased, the inner configuration of protein has loosed, copper broken away from protein center.

This research used a new method—ESR to study the configuration of azurin, spinned the spin label 3-maleido-proxyl to the -SH- of azurin specifically, according to the change of τ_c in the spectrum of ESR to embody the alter of inner configuration of protein.

In the case of using guanidine HC1 denaturalize, with the increase of guanidine concentration, the τ_ c of spin label decreased, this indicate that the inner stereo-structure of protein has loosen, and the configuration has relax.

Correlation functions of gas-dynamic parameters at the pipeline boundary are studied and the corresponding characteristics (correlation time, delay time, etc.) are determined from the model for different initial and boundary conditions.

A share of membrane-bound spin probe was different for chloroplasts and subchloroplast fragments, as well as its rotational correlation time and apparent enthalpy and entropy activation of nitroxide rotational motion.

However, the rotational correlation time τ for spin-labeled Bs and its complex with Bn in solution corresponded precisely to their molecular weights.

It is likely the spin correlation time of the triplet states is longer than the lifetime of the complexes.

Basic parameters of the correlation (time, distance, relaxation time) are calculated from experimental data.

The molecular motional correlation times of two pairs of protons, H-1a/H-1b and H-2/H-3, in the bound state at T = 298 K were 11.7 and 9.46 ns respectively, while they were 27.7 and 35.2 ps in the free state.

Experimental D*(t1) dependences have been shown to be adequately described by the relations of the Fatkullin theory for moderate and short correlation times of spin motion in an internal random Gaussian magnetic field.

The correlation times of plasma fluctuations in the Z-direction are estimated, and diffusion coefficients in the Z-direction are calculated.

The dependence of apparent IC50 values on the rotational correlation times of 4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine and its derivatives in model micellar systems was analyzed.

The informative parameters extracted from S(f) and Φ(p)(τ) describe correlation times and characterize loss of "memory" (correlation links) in these correlation time intervals for the "spike" and "jump" irregularities.

The 13C total spin-lattice relaxation times and the NOE factors of N-butyl aniline were measured at two temperatures by means of inversion recovery pulse sequences (180-t-90T).The contributions of each relaxation mechanism were appreciated by calculation, the correlation times re of molecular random movements were deduced, and the dynamic situation of the molecules was discussed

The changes of cell membrane properties after carcinogenesis are important subjects. This paper reports the differences between the properties of HEP.A22 mouse ascites cell membrane lipids and those of the control cells. Two types of fatty acid spin labels Ⅰ(12,3) and Ⅰ(1,14) were used and the order parameters, rotational correlation times and half amplitude angle of wobbling for lipiid were determined. Arrhenius plots in range from 0℃ to 50℃ for both cells were done simultaneously. It was found that the order...

The changes of cell membrane properties after carcinogenesis are important subjects. This paper reports the differences between the properties of HEP.A22 mouse ascites cell membrane lipids and those of the control cells. Two types of fatty acid spin labels Ⅰ(12,3) and Ⅰ(1,14) were used and the order parameters, rotational correlation times and half amplitude angle of wobbling for lipiid were determined. Arrhenius plots in range from 0℃ to 50℃ for both cells were done simultaneously. It was found that the order parameters of the cancer cell membraneare larger than those of the normal cell, but the wobbling half aplitude angle of fatty acid chain of cancer cell membrane is smaller than that of the normal cell in the depth of membrane; on the contrary at the surface of the membrane, the case is just the opposite. From the Arrhenius plots it was found that the phase transition temperature of the cancer and control cell membrane lipids are 18℃ and 30℃ respectively at the surface of the membrane, but in the depth of the membrane, the phase transition point is not found in range 0°—50℃ for both cancer and normal cells.

The ~(13)CNMR relaxation of polystyrene and its block copolymers in solution has been investigated. Relaxation parameters T_1 and NOE were determined and the variation of apparent T_2 with temperature was observed from the plots of linewidths versus temperatures, a log X~2 distribution function representing the spectra of correlation time has been used to simulate the relaxation parameters at various temperatres. Experirimental results proved that there were multiple transitions in the molecular motion of polystyrene...

The ~(13)CNMR relaxation of polystyrene and its block copolymers in solution has been investigated. Relaxation parameters T_1 and NOE were determined and the variation of apparent T_2 with temperature was observed from the plots of linewidths versus temperatures, a log X~2 distribution function representing the spectra of correlation time has been used to simulate the relaxation parameters at various temperatres. Experirimental results proved that there were multiple transitions in the molecular motion of polystyrene and its block copolymers. The relaxation parameters at various temperatures were closely related to molecular structure. For CH carbon on polystyrene there were two transitions on T_1—T and H1/2—T curve, corresponding to the rotation of thephenyl group and the main chain segmental motion. There also existed the relationship that the transition temteratures of homopolymer were greater than that of the block copolymers. Therefore, ~(13)C NMR relaxation parameters can also be used in the characterization of block copolymers,