The system of polyacrylamide hydrogel has been studied by means of Nuclear Magnetic Resonance Microscopy. There were four PAMG samples, which had been cross-linked by γ irradiation, with different degrees of swelling in D₂O. The proton spin-density distribution images of cross-linked networks in PAMG have been obtained.The experimental results have directly and clearly shown that the dimension of the cross-linked networks varies significantly with the degree of swelling of PAMG samples.

To Characterize the molecular structure of oligomers and polymers of Poly(aryl ether ketone)s family,this paper presents a series of Chain-extended monomers and mono-dispersed Oligomers.The comparison researches on these compounds dissolved in DMSO-d₆(or DMSO-d₆+CDCl₃) and H₂SO₄-d₂(or H₂SO₄) are made by ¹³C NMR method.Results show that, in H₂SO₄, their molecular structures are greatly polarized.Results from quantum mechanical calculation and dynamic ¹³C NMR show that this polarization results from the charge unlocalization of bridge-bonds and aryl-rings in molecular chain induced by sulfo-group of H₂SO₄,but not from the reaction of sulfo-group.The Polarization route for the titled compounds are firstly suggested.

A new triterpene and three new triterpenoid glycosides were isolated from Ilex kudincha.Their chemical structures were determined by 2D NMR spectra.The whole assignment of proton and carbon NMR spectra is given for the first time.

Metabolism of 5-fluorouracil(5FU) in mouse liver and implanted S180 tumor was studied using in vivo ¹⁹F NMR spectroscopy. The half-life of 5FU elimination is about 15-20min in liver and 50-60min in tumor.Catabolites of 5FU,fluorouredopropanic acid and α-fluoro-β-analine,were observed in livel, while only the fluoronucleotides,anabolites of 5FU,were observed in tumor. The results show that NMR spectroscopy is a powerful method for metabolic and pharmacokinetic studies.

The ¹H NMR and ¹³C NMR spectra of 9-fluorenylmalononitrile,ethyl α-cyano-α-(9-fluorenyl) acetate,α-cyano-α-(9-fluorenyl) acetamide have been reported and all the chemical shifts of ¹³C and proton have been assigned according to substituent effeCt,H-H COSY,C-H COSY HMBC,MS spectra of their 9-deuterated compounds.

Two low-pass J-filters are introduced into HMBC experiment to suppress all direct J-coupling peaks and do away with the interference of direct J-coupling peaks and long range J-upling peaks which may occur in HMBC spectra of some molecules. Theoretical analysis and experiments show that the purpose of suppressing all direct J-coupling peaks can be achieved with almost no loss of intensity of long range J-coupling peaks.

Imperfection of analog components and influence of distributed parameters led to the rf leakage in the modulation of a shaped pulse.The rf leakage produced big artifact to the excitation profile of the shaped pulse.In this article,the artifact was analyzed on the basis of the theory of rf amplitude modulation.A new phase cycling pulse sequence was designed to reduce such kind of artifact.Experimental result showed that this phase cycling method is practical to the improvement of the feature in the selective excitation unit.

Five single crystals of the natural diamonds,four Synthetic diamonds and two diamond-like films (PCVD film) have been investigated by means of ESR method. The results show that there are four kinds of N-center free radicals and one kind of C-center free radical in the I_b type natural diamonds, and the unpaired electron is located on an antibonding orbital of the N3 impurity center in the I_aB3 type natural diamonds.The ESR spectra of the I_b type synthetic diamonds are similar to the natural diamonds,except that the linewidthes are broader since they contain some paramagnetic elements,such as Ni,Fe,etc.For diamond films,the concentration of the C-center free radicals varies greatly. however,the concentration of the N-center free radicals,which are usually quite low in diamond-like films, varies relative slightly.Finally,the two satellite peaks of the C-center free radicals are found to be the direct evidence of the existence of hydrogen atoms in the PCVD films.

It was found with electron-spin-resonance(ESR) that the doped silver is Ag⁺,and no ESR signal or Ag²⁺ was observed in ZnS crystallite. With ESR of probe ion Mn²⁺ and X-ray diffraction analysis, it was found that a structure phase transformation from cubic lattice(β phase) to hexagonal(α phase) in ZnS crystallite is affectd by doped amount of Ag⁺ ion and calcination temperature. There is a reverse transformation phenomenon when Ag⁺ doped amount is 5×10^-4g/g and at 1100℃-1200℃.The Landé factor g of α phase is 2.006,the hyperfine constant a is 6.76mT,the g of β is 2.002,a is 6.81 mT from ESR of the Mn²⁺.

Problems associated to signal automatic recognition by Neural Networks is studied with computer simulations and ¹⁴N remote NQR experiments.The effectiveness of the multiple layer back propagation algorithm for solving the problems is venfied.The experimental result indicates that,under the condition of very low signal-to-noise ratio and very strong interferences,the B-P algorithm still keeps a very high recognition (>90%).This is of significant improtance in remote NQR applications.

This paper deals with the studies of HMBC spectra of caohuoside A and sagittatoside B isolated from the aerial parts of Epimedium koreanum (Berberidaceae). A reappraisal was made for C-5, C-7 and C-4' chemical shift assignments of anhydroicaritin-3-O-glycosides in literatures.

The ¹³C NMR spectra of fifteen new tris(2-methyl-2-phenyl propyl) tin aryloxyacetates were recorded.The chemical shifts of various carbon resonances have been assigned on the basis of calculation and comparison with the chemical shifts of the model compounds.The data of the effect of substituent of on the ¹³C chemical shifts in benzene ring were obtained:C_ispo=30.0,C_ortho=-13.8,C_meta=0.8,C_para=-7.5.

Application of shaping filtering in digital signal processing to the measurement of remote nuclear quadrupole resonance signals is discussed in the present article.The shaping filtering procedure is accomplished with Turbo-Pascal Language on a personal computer.Enhancement of signal-to-noise ratio by the shaping filtering is demonstrated by numerical simulations and ¹⁴N remote NQR experifmental data of a powdered NaNO₂.