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71.
Y. Lian H. Gao S. X. Dou H. Wang P. Ye Q. Guan J. Wang 《Applied physics. B, Lasers and optics》1994,59(6):655-658
Mechanism transitions of Self-Pumped Phase Conjugation (SPPC) with wavelength and doping concentration are observed in KTN:Fe (KTa1 –x
Nb
x
O3:Fe with
x
= 0.48) crystals. The SPPC mechanism in KTN: Fe (0.4 wt. %) crystal transforms from Stimulated Photorefractive Backscattering and Four-Wave Mixing (SPB-FWM) to cat (or total internal reflection) as the wavelength increases from 514.5 nm to 620 nm. SPPC at 514.5 nm is formed with the cat mechanism in a 0.2 wt. % doped KTN:Fe crystal, while with the SPB-FWM mechanism in a 0.4 wt. % doped one. These mechanism transitions are discussed with respect to the dependence of the backscattering gain coefficient of the crystals on wavelength and doping concentration. 相似文献
72.
73.
74.
Ramasamy、Osuka等用NaHTe/EtOH研究了二卤代物的脱邻二溴、偕二溴反应和α-溴代羰基化合物的脱卤还原反应,我们选择结构不同的卤代物以NaHTe还原,发现在水介质和催化量碲代替计算量碲时也能顺利地进行这类反应,其反应条件温和,产率高,是有机官能团转化的好方法。 相似文献
75.
A new method for indirect determination of captopril (CPT) with NaNO3 and NH4SCN by floatation and separation of copper has been studied. In the weak acid, a small amount of Cu(II) can be reduced to Cu(I) by CPT, then Cu(I) reacted with the SCN, which can float on the surface of the liquid phase with NaNO3. A good linear relationship is observed between the floatation yield (E%) of Cu(II) and the amount of captopril. The linear range is 2?32 mg/L. On the ground, captopril can be indirectly determined by determining E(%) of Cu(II). The method is simple, rapid, reliable and has good selectivity. The developed method can be applied to indirect determination of captopril with satisfactory results. 相似文献
76.
Chun Hua Ge Xiang Dong Zhang Yong Chao Ma Lei Guan Chun Yue Shi Xiao Yan Zhang Ya Nan Guo Qi Tao Liu College of Chemistry Liaoning University Shenyang China 《中国化学快报》2007,(11)
The preparation and crystal structure of complex Co(Hsae)_2·2H_2O (1,H_2sae=N-salicylidene-2-iminoethanol) are reported.X- ray analysis revealed that every six Co(Hsae)_2 forms a cyclic chip and every 12 water forms a novel gear-like cluster.Acting as building blocks,the gear-like water cluster and complex chip are connected in A-B fashion and extend into one-dimensional supramolecular chain.Hydrogen bond is the primary bridging force in the formation of supramolecular framework. 相似文献
77.
多巴胺 (DA)和抗坏血酸 (AA)的吸收光谱在 2 0 0~ 30 0nm内重叠严重 ,但在电化学氧化状态下 ,DA的氧化产物在 2 10 ,30 0和 4 80nm有强吸收峰 ,AA的氧化产物在 2 0 0~ 4 0 0nm范围内吸收较弱且呈光滑平缓的斜坡。在此基础上 ,利用自行设计的长光程薄层光谱电化学池建立了一种双波长光谱电化学法测定DA。测定条件为 pH 6 .2的磷酸盐缓冲液 (PBS) ,0 .6V (vs.Ag/AgCl)电极电位 ,双波长 318/ 2 93nm ,线性范围为 4 .0× 10 - 6 ~ 2 .0× 10 - 4mol·L- 1,检出限为 2 .0×10 - 6 mol·L- 1。对 6 .2 0× 10 - 5mol·L- 1DA进行 11次平行测定 ,平均相对偏差为 2 .6 %。与文献报道的吸光光度法相比 ,该法具有较高的灵敏度和选择性 ,较为有效地消除了AA的干扰 ,回收率在 91.8%~ 10 0 .8%之间 ,结果满意 相似文献
78.
The reductive alkylation of amine with carbonyl compounds usingsodium hydrogen telluride has been investigated in recent years.Application of this method to the synthesis of N-alkyl derivativesof biologically important amino acids and their esters is described. 相似文献
79.
It is usually reported that reaction between carbonyl and P2S5 produce thiono group compound. The Products from carbonyl after ammonolysis and hydrazinolysis have the very import applied value in the synthesize of heterocyclic compound. Sulfuration reation if a nucleophilic attack, SPS2 anionsid obtained from P2S5 in the organic sovent, rather easier than thereationsof scheeren’s reagent. The reation mechanism is as follows: The reation speed has something todo with the electronegative of… 相似文献
80.
Study of Tea Digitized Chromatographic Fingerprint Spectra Using Micellar Electrokinetic Chromatography 总被引:1,自引:0,他引:1
IntroductionTeaisthemostwidelyconsumedbeverageinpeople’slife .Theheightenedpopularityofthisbeveragethroughouttheworldinrecentyearsmaybedueinparttotheevidenceofarelationshipbetweenteaconsumptionandpreventionofcertainformsofhumandisease .Themaincomponentsofteaarepolyphenoliccompounds ,commonlyknownascatechins ,whichrepresentagroupofcom poundsbelongingtotheflavonoidfamily .Thesecom poundsarewidelydistributedinthetealeavesandconsti tuteupto 30 %ofthedryleafweight.1Muchinteresthasbeenfocusedoncat… 相似文献