The ¹³C-NMR spectra of the alternating copolymer of isoprene with methyl mcthacrylate and its block copolymer, poly (styrene-alt-methyl acrylate) -block-poly(isoprene-alt-methyl methacrylate) -block-poly(styrene-alt-methyl acrylate), have been studied. The results indicated that all blocks of the block copolymer have completely alternating structure and the isoprene units presented mainly with trans-1,4-structure. It was observed that there were two addition modes of isoprene and methyl methacrylate, "head to head" and "head to tail", while the former was predominated.

The ¹H-NMR method was applied to the determination of NCO/OH molar ratio in the PPG-2, 4 TDI-based polyurethane prepolymer systems and the determination of the number average molecular weight of PPG in the systemt. Finally the molecular weight of prepolymer can be calculated.

The proton spin-lattice relaxation times in transpolyacetylene versus Larmor frequency ω and temperature T were reported and analyzed by Nechtschein et. al. (2). The ω^-1/2 dependence of the proton spin-lattice relaxation rate T₁^-1 in trans-polyacetylene was obaerved. However, at high frequency the data deviate from ω^-1/2 at a certain frequency which becomes lower and lower as temperature is decreased.
These experimental results are analyzed in a different way in this paper. First, the justification for 1D-soliton diffusion model is discussed. The interpretation whereby only nuclear spin flip diffusion to static paramagnetic centers gives rise to ω^-1/2 behaviour in the proton relaxation rate is ruled out. Solitons can be either in mobile state or in fixed state. As the temperature decreases two effects take place, that is, there are fewer and fewer solitons in the mobile stale and the diffusion coefficient of mobile Solitons decreases. Only diffusive solitons are responsible to the observed proton relaxation, while the contribution from fixed solitos are negligible. Secondly, a 1D random walk model for mobile solitons is described and its correlation function and spectrum density function are calculated. The proton spinlatticc relaxation rate is

where C is the density of mobile soliton, τ is the hopping time of mobile soliton between adjacent sites along the chain, and ω is the Larmor frequency of proton.
Theoretical curves obtained from this formula fit with Nechtscheins measurement very well. The hopping time and relative density of mobile solitons at various temperatures are extracted,

In this paper a plan is proposed for a bulb-Rb⁸⁷ coated maser without buffer gas A specific coated bilb design is given for the maser. The osillation condiction of the maser is discussed and the short term stability of the maser is estimated. It is shown that such a maser might be developed to be a maser with good stability short term, long term.

The ¹³C NMR spectra of curcumol and curdione, which are active components for antitumor in the Chinese herbal medicine, curcuma aromatia silisb, as well as acetyl and epoxy derivatives of curcumol were recorded, and the spectral lines were ossigned. By NMR and other techniques the molecular structure of an artificial modified product of curcumol CM-I was determined. It is a new derivative of cycloheptatrienyl ketone with Strong physiological activity.

The moleculer structures of eight alkylaminopyridines, seven of them are new compounds, were determined and investigated. The assignment of ¹³C NMR spectral lines has been made by double irradiation NMR and other techniques. The substitutive parameters of NMR and NR, groups for pyridine ring and those of pyridyl amine for alkane were worked out and compared with those of NH₂ group. The variations in electron cloud density were also discussed.

EPR and ¹³C-NMR techniques were used to study systematically tbe new free radical products formed by the reaction cf D-gluoose with amino acids. The hyperfine structure and splitting line numbers of EPR spectra of the free radical products depended mainly upon the structure of amino compounds, and could be assigned to the contributions of one set with two equivalent nitrogens and of three sets of equivalent protons. The chemical shifts of ¹³C-NMR spectra of the free radical products showed that ihe principal structure would be:According to the analyses of EPR,¹³C-NMR spectra and the reaction processes,, We propose the assumption of theidentity of the radical product as 1,2-1, 5 tetrasubstituted piperazine biradical. The assumed structure and EPR spectral analyses mechanism were strongly supported by the close agreement between, the observedSpectra and those simulated on aspect 2000 computer. The proposed mechanism of the free radical formation in the reaction of sugar withamino acids is presented in this paper.

This article describes trie computer system of spin-echo spectrometer, which consists mainlc of TP-801 computer, peripheral devices, interface circuits and a set of applied software The system can produce various pulse sequences, which meet the requirement of spin-echo experiments, including 90-90,90-180, 180-90 and carr-purcell pulse sequences etc. At the same time, the computer system acquires FID and spin-echo signals and processes data collected. The results can be shown directly on oscilloscope and plotter, and also can be stored in tape. Relaxation time T₁ and T₂ can be measured fast and accurately. It also can be used in teaching of NMR spin-echo. In the last part of this article, results of measurement of a group of samples are given. The computer system described by this article is also fit to combine with general CW-NMR spectrometer to enable it to have function of spin-echo measurement.

In this paper, a scheme for applying DEPT technique to T₁-measurement of insensitive nuclei is introduced. Is it shown experimentally that this scheme not only retains the inherent advantages of DEPT technique, but also displays additional advantages ia thortening measurement time and in simplifying T₁-calculation.

In the present paper, the bulk susceptibility of rare earth ions in aqueous solutiona has been studied by NMR two-spectrometer method. The experimental relults are in good agreement with that predicted by Curie's law.

In this paper the study on ¹H NMR and ¹³C NMR of alpha and/or beta substituted N-(p-chIoro cinnamyl) -sec-butylamineg is reported. Bated on the data or NMR the configurations of these compounds were asgigned.

A description of the experimental technique of saturation transfer electron paramagnetic resonance (ST-EPR) is given by using maleimide spin labeled hemoglobin as an example. It relates to the main points of the sample preparation and the experimental measurement as well as determination of the parameters of ST-EPR spectrum. In addition, the present paper goes further into the problems about the influences of the experimental conditions on ST-EPR spectra.

Application of Hadamard transform in nuclear magnetic resonance (NMR) imaging enhances the sensitivity of NMR imaging. In this paper we explained the principle of line scan Hadamard transform NMR imaging and deducted the relation of Hadamard cede to the phase of excitation signals. We obtained phase table of synthesis frequency excitation signal. The Hadamard transform NMR imaging using spin echo was discussed in details.