The results showed that ultraviolet absorption spectrums of DNA combined with NaF of different levels changed obviously. The characteristic absorption wavelength of the mixture F calf DNA and λDNA changed from 202nm to 197nm and 220nm respectively, the displacements were 5nm and 18nm respectively with the decrease of absorption intensity.

The chromatography conditions of HPLC were found: the mobile phase was methanol mingled with water (V_(methanol):V_(water)=30 : 70) ; the flow rate was 1.2mL/min; 238nm was the thiamine detection wavelength and the column temperature was 35 ℃.

The results showed that the characteristic peak is 275.8 nm,and the emission peak appear at 316.3 and 623.6 nm with excitation wavelength of 279.0 nm in pH 7.45 buffer solution,However,when pH>10,the UV absorption spectrum and fluorescence spectrum of dopamine change with pH changing.

Its molecular structure has been identified with IR, MS, ~1H-NMR, ~(13)C-NMR and elemental analysis and the Uvλm of DAFF and the two intermediates is obtained.

Concentrated phosphoric acid was used for the preparation of tested solutions as a solvent. The specific wavelengths of U6+ and U4+ ions were selected at 310 nm and 544 nm, respectively.

For a study on the forked conjugative system and its relation with the corresponding linear conjugative series,in this paper three type with 11 compounds of forked conjugative azachalcone homlogs. (2P0nB,4P0nB,2QonB) have been synthesized, of which the starred ones are new compounds.The I. R. specrra of these compounds have been determined.The experimental results show that some particular group absorption wave numbers (e · g · carbonyl, ethyl) conform well to the rule of homologous linearity, with correlation...

For a study on the forked conjugative system and its relation with the corresponding linear conjugative series,in this paper three type with 11 compounds of forked conjugative azachalcone homlogs. (2P0nB,4P0nB,2QonB) have been synthesized, of which the starred ones are new compounds.The I. R. specrra of these compounds have been determined.The experimental results show that some particular group absorption wave numbers (e · g · carbonyl, ethyl) conform well to the rule of homologous linearity, with correlation cofficients ranging from 0.982 to 1.000.The reason for this is probably that the molecular vibration energies of the homologous compounds also conform approximately to the rule of homologous linearity.when the homologous lines for the group's characteristic absoption wave numbers of the forked systems are compared with those of the corresponding linear homologs, it has been found that the former locate lower than the latter, and with a smaller slope. this shows that the introduction of an electron-attractive pyridyl or quinolyl as a branching group causes a red shift in the charecteristic absoption wave length.This fact lends support to the conclusion that the moleclar integrity is the main trend in the forked systems, and the forking group's effect is under the restraint of it.

Forty green tea samples were scanned by NIR light.A stepwise multiplelinear regression analysis of the second derivative spectra of green tea selectedfour wavelengthes in the order of 2088,1684,2042 and 2046.The calibrationequation is as follows:C(T-N%)=3.302+1.721d_2OD(2088nm/1684nm)+0.905d_2OD(2042nm/2046nm).The standard deviation of difference(s)is0.0723,and the correlation coefficient(r)is 0.9964.The above equation wasverified with 27 green tea samples.The high relationship between the totalnitrogen contents...

Forty green tea samples were scanned by NIR light.A stepwise multiplelinear regression analysis of the second derivative spectra of green tea selectedfour wavelengthes in the order of 2088,1684,2042 and 2046.The calibrationequation is as follows:C(T-N%)=3.302+1.721d_2OD(2088nm/1684nm)+0.905d_2OD(2042nm/2046nm).The standard deviation of difference(s)is0.0723,and the correlation coefficient(r)is 0.9964.The above equation wasverified with 27 green tea samples.The high relationship between the totalnitrogen contents from chemical analysis and NIR analysis was obtained,andthe correlation coefficient and the standard deviation of difference are 0.993and 0.0808 respectively.T test showed that the difference between the dataobtained from NIR and chemical method was not obvious.It is concludedthat NIR method can be used to analyze the total nitrogen content in greentea.

通过对40个绿茶样品进行近红外光扫描和多元回归分析处理,求得总氮的近红外特征吸收波长为2088毫微米,计算绿茶的总氮量的多元回归方程式为 C_((T-N%))=3.302+1.721d~2OD(2088毫微米/1684毫微米)+0.905d~2OD(2042毫微米/2046毫微米),标准偏差 S=0.0723,相关系数 r=0.9964。径用27个茶样验证,r=0.993,S=0.0808,并经 t 检验,近红外法和化学法测定结果差异不显著。因此,确认近红外测定绿茶的总氮量的分析方法,可以用于绿茶的品质检验。

The near-infrared reflectance(NIR) spectra of forty green tea samples were determined. The characteristic bands associated with the four quality contents, total nitrogen, free amino acids, coffeine, and tea polyphenols of green tea, were found, multiple linear regression analysis was done, and corresponding regression equation was established. The equations were verified with 31 green tea samples. The correlation coefficient(r) and the standard deviation of difference(s) are r=0. 993, s=0. 0808 for total nitrogen,...

The near-infrared reflectance(NIR) spectra of forty green tea samples were determined. The characteristic bands associated with the four quality contents, total nitrogen, free amino acids, coffeine, and tea polyphenols of green tea, were found, multiple linear regression analysis was done, and corresponding regression equation was established. The equations were verified with 31 green tea samples. The correlation coefficient(r) and the standard deviation of difference(s) are r=0. 993, s=0. 0808 for total nitrogen, r=0. 888, s=0. 228 for free amino acids, r=0. 917, s=1. 29 for coffeine, r=0. 998 s=0. 146 for tea polyphenols. T test showed that the results both chemical analysis and NIR analysis are in good agreement. It is concluded that NIR method can be used to determine the total nitrogen, free amino acids, coffeine and tea polyphenols in green tea.