Main magnet, scan magnet and magnetic gradient coils used for L-band t hree dimensional electron paramagnetic resonance imaging were developed. Instead of using the conventional copper wire design to wind the gradient coils, they w ere built using a whole copper plate with the electrical line cut technique. The  new design remarkably reduced the volume of the gradient coils, and made the ma in magnet more effective. The maximum gradient strengths in all three directions  reached more than 200 mT/m with a driving current of 20 A. The spatial linearit y  of the gradients in all three directions was better than 5 %, and the linear ran g e was larger than a sphere of 42 mm in diameter. The distance between the surfac e s of the gradient coils was 63 mm, which was large enough to contain any type of   L-band EPR cavity. The main magnet and the scan magnet coils were fixed on an iron frame. The magnet fields generated by the two magnets were 1.6～96 mT (main  mag net) and 0.2～16 mT (scan magnet), respectively. All five magnet coils (main, sc an  and three gradients) were driven with five independent instant current power su pplies, which were controlled by a computer through a data interface. The prelim inary imaging test showed that the magnets are practical for 3D-EPRI applicatio ns.

Magnetic Resonance Imaging (MRI)，as a non-invasive diagnosis method, has been widely used in many fields. However, students may have no chance to per form MRI experiments on commercial scanners, mainly due to the cost. In order to overcome this problem, we have constructed a bench-top MRI system in our labor a tory for teaching purposes. Detailed discussion about the system design is given  in this paper, including both hardware and software. The performance and reliab ility of our homebuilt bench-top MRI system were verified with some conventional MRI experiments. The results indicate that the system we designed can be used for educational applications.

NMR spectroscopy methods were used to study the metabolic changes of A TP, PME and lipid during harringtonine (HT) induced apoptosis in HL-60 cell. After HL-60 cells were treated with HT for two hours, it was observed by ³¹P-NMR sp ectroscopy that the levels of ATP and PME decreased significantly and intracellu lar pH increased significantly. It was also found by ¹H-NMR a significa nt increa se in the signal intensity of methylene resonance and a slight decrease in choli ne peak in treated HL-60 cells. The present investigation will be helpful for  understanding the mechanism of Harringtonine induced apoptosis in HL-60 cells.

The silica gel carried γ-chlopropyltrimethoxysilane and γ-aminopropyl trimethoxysilane were characterized by nuclear magnetic resonance spectrometry.  It was shown that the hydroxyl groups on the surface of silica gel substrate giv es only non-distinctive bands. The intensities of the bands related to the surface hydroxyl groups can be remarkably enhanced by cross polarization. The result  suggests that γ-chlopropyltrimethoxysilane and γ-aminopropyltrimethoxysilane  we recarried on the surface of the silicagel, and the reactions were relatively completed.

Cefazolin is an antibiotic, and sodium cefazolin is commonly known as  cephalexin. Solid complex of cefazolin with Eu³⁺ ion was synthesized in this study by the coprecipitation method. The complex synthesized was characterized by fluorescence spectroscopy, infrared spectroscopy (IR), thermal spectroscopy, scanning electron microscopic photographs and element analysis. The coordination sites of the complex and the mechanism of the complexing reaction were studied by  IR, ¹H NMR and ¹³C NMR.

In order to understand injuries occurred in erythrocytes treated with  the methylene blue (MB) photochemical method, the changes of high-energy phosph a temetabolites in the treated erythrocytes were studied by ³¹P NMR. T he control and treated erythrocyte samples, which originally allcame from stored blood of  healthy adults, were measured by ³¹P NMR with an MSL-300 MHz spectr ometer. L-hist idine was added to half of the treated samples before the treatment. The effects  of the MB photochemical method on the erythrocytes were studied by measuring the relative changes of 2,3-DPG, ATP and (PME+SP) contents. In erythrocytes treat e d with MB photochemistry, the contents of (PME+SP) increased significantly, and  the contents of 2,3-DPG and ATP decreased significantly. Our data suggest that, in the MB treated erythrocytes, glucose metabolism through the pentose phosphate pathway increases significantly. It is concluded that MB treatment may affect physical, chemical and functional properties of erythrocytes to some degree, and such effects can be ameliorated by L-histidine.

Reaction of 1,8-diazabicyclo\[5,4,0\] undec-7-ene (DBU)  with perfluoro- 2-alkynoates yielded tricyclic derivatives. The products were analyzed by ¹H NMR,   ¹³C NMR and 2D NMR spectroscopy. The resonances in ¹H NMR and ¹³C NMR spectra  were assigned, and the structures of the products were determined. The pathways  and the mechanism of the addition reaction were also discussed.

Based on the results from five compounds: methylether, ethylether, n-propyleth er, em-propylether and t-butylether, an empirical equation: δ_cal=δ_0n+Δα+Δβ+Δγ (Eq. [1]) was derived for calculating the ¹⁷O-NMR chemical shifts of  chained aliphatic ethers. Parameters were obtained for 29 substituents using lin ear regression in combination with least square analysis. The validity of Eq. [1] was checked regressively by 147 ¹⁷O-NMR chemical shifts of 147 chained aliphat ic ethers. The confidence limit was 99.5 % and the calculating errors of about 9 0 % compounds were less than 5 ppm (relative errors 0.5 %).

The relation between the ¹³C chemical shift of C=O in alkyl substitute d compound RXC=O and the polarizability effect index (PEI) of alkyl group R can  be expressed as
δ=a+b·ΣPEI(R)
where a and b are empirical constants. Regression analysis showed that the equat ion is a good expression for the ¹³C chemical shift of C=O change rule  with the  polarizabality effect index of alkyl group. The results also showed that the pol arizability effect index of alkyl group R increase the ¹³C chemical sh ift of C=O.

2D NMR (¹H-¹H COSY, HMQC and HMBC) methods, among which the HMBC metho d was the most important, were used to elucidate the structure of Elisabatin B ( i.e, diterpene with 11 quaternary carbons). The ¹H and ¹³C chemi cal shifts were  assigned. Compared with the results reported in reference, the chemical sh if ts of 11 more quaternary carbons were determined. The results of this study sugg est that the 2D NMR techniques can be applied to and are useful in structural el ucidation of natural products.

The fluorine-containing lactones are often present in natural organic- compounds. In this study the structures of three fluorine-containing lactones were determined using the NMR techniques（¹H NMR，¹³C NMR，¹H -¹H COSY，NOESY，HMB C，HMQC）. Two-dimensional NOESY was especially useful for providing information on the stereo configuration of the compounds. Knowing the structures can be help ful in studying the mechanism of chemical reactions involving fluorine-containi ng lactones.

Indole derivatives are important pharmaceutical compounds often used for anti-anxiety treatments. In this study, the structures of a serials of indole based co mpounds were determined by ¹H, ¹H-¹H COSY, MSFAB, IR and ele ment analysis. The ¹H chemical shifts of the compounds were assigned. The  positions of the substitute groups were determined by ¹H-¹H COSY. The ¹H chemical shifts of different indole derivatives were compared.

In rigid lattice, chemical shift is a tensor depending on the spatial orientation of the external magnetic field. The tensor has six independent components. The  orientation of chemical shielding tensor can be expressed with direction cosine s of its principal axis system. It is of great interest that if the chemical shi ft tensor of each nonmagnetically equivalent nucleus is known, the information o n the distribution of the electron cloud in the molecule can be deduced from the se tensors. In this paper, the theory and methods of measurement of chemical shi ft tensor are reviewed. A number of common methods are discussed in detail, such  as 2D magic angle hopping (MAH), 2D magic angle turning(MAT), and 2D phase-adjusted spinning sidebands(2D-PASS) technique and so on. The common metho ds for measuring single crystal chemical shielding tensor are also discussed.