Volumes of activation for dissociation of pentacyanoferrates(II) through pressure and salt effects on reactivity

Summary Dependences of rate constants on pressure (up to 1 kbar) and on added salt concentration (up to 6.0 mol dm^–3 LiNO₃, NaNO₃, NaCl, Na₂SO₄ or KNO₃) have been established for dissociative substitution of pentacyanoferrates(II), [Fe(CN)₅L]^3– with L = 4-cyanopyridine, 4,4-bipyridyl, 4-phenylpyridine and 4-t-butylpyridine. Activation volumes derived directly from pressure effects, and indirectly from salt effects via surface tension dependences and derived surfaces of activation, are reported, compared and discussed.     

镧的植物防病效果及其生物学效应

通过灭菌土接种Rhizoctonia solani以及混合接菌Rhizoctonia solani和Fusarium solani进行盆栽试验,分别研究了镧浸种处理对高羊茅及板蓝根出苗、生长发育的影响。结果表明,镧浸种能明显地减少病原菌的侵染,对由其所造成的种腐、芽腐及根腐等有显著的防治效果,提高了板蓝根和高羊茅种子的出苗率。同时,镧浸种在适当的浓度范围内,还能显著地促进植物的生长发育,生物量明显增加。利用盆栽水稻试验研究了稀土镧对水稻纹枯菌(Rhizoctonia solani)的毒力,测定结果表明,镧喷施于水稻植株上对水稻纹枯病有明显的防治效果,且在活体条件下,喷施镧后1和7 d对水稻纹枯菌(Rhizoctonia solani)的有效中浓度分别为128.7和128.1 mg.L-1,均明显低于离体条件下的有效中浓度(171.9 mg.L-1)。     

Dynamic ultrasound-assisted extraction of polyphenols in tobacco

A novel extraction method, namely dynamic ultrasound-assisted extraction, is investigated. This technique is efficient with respect to both time and solvent consumption because it utilizes ultrasonic energy in dynamic mode during extraction. Polyphenols (chlorogenic acid, esculetin, rutin, scopoletin, and quercitrin) are extracted from a tobacco (Nicotina tobaccum L.) sample for 10 min with 6 mL of solvent. Fresh solvent is continuously pumped through the sample, with which the analytes can be rapidly extracted, and the possibility of degradation efficiently avoided. Methanol involving 0.5% w/v ascorbic acid was used as extraction solvent; optimal flow rate and extraction time were investigated. The extract was cleaned up by C18 disposable cartridge. The spiked and nonspiked tobacco samples were used for the evaluation of the proposed method. Recoveries obtained were varied from 96 to 108% and RSDs from 2.0 to 4.6%. This extraction technique was revealed to recover larger amounts of polyphenols from tobacco, compared to the static ultrasound-assisted extraction method.     

用环形扩散管和滤纸联用采样技术采集空气中氨和铵盐

建立了环形扩散管和滤纸采样夹联用，分形态同时采集空气中所态氨和颗粒态铵盐的方法。在同一气流中，采用涂渍１．５％草酸乙醇水溶液的环形扩散管采集气态氨，用浸渍上述试剂的玻璃纤维纸和慢速定量滤纸分别采集颗粒安和第一层滤纸上的铵盐挥发产生的氨气。用靛酚蓝比色法分别测定氨和铵盐。当采气流速为１．０Ｌ／ｍｉｎ时，采样效率高于９８．２％。将本法测得的氨气和铵盐的总量与标准采样方法的测定结果比较。无显著性差异（Ｐ     

茶碱对聚苯胺尿酸酶电极的生物电化学活性的抑制

用聚苯胺尿酸酶电极研究了茶碱对固定酶的影响，结果表明，茶碱对固定尿酶酶有明显的抑制作用，但这种抑制作用是可逆的，在茶碱的存在下，ＰＨ对酶电极的响应电流影响与无茶碱存在时不同；在０．２－０．５Ｖ之间，酶电极的响应电流随电位加而迅速升高，当电位进一步升高时，其变化速度减慢，茶碱使尿酶酶催化反应的活化能从无抑制剂存在的时的２９．９ｋＪ．ｍｏｌ＾－１提高到４７．８ｋＪ．ｍｏｌ＾－１，即抑制剂改变了尿酸催化     

POLYMERIZATION OF OCTAFLUOROCYCLOBUTANE IN GLOW DISCHARGE Ⅱ. ESCA AND IR CHARACTERIZATION OF POLYMER STRUCTURE*

In a capacitively coupled discharge with external electrodes, He, H_2, N_2 or Ar were used as plasmagas, polymerization of octafluorocyclobutane was carried out under different conditions by varyingdischarge power, pressure, plasma gas and plasma-gas/monomer ratio. Structure of polymerizedproducts was characterized by IR spectroscopy and ESCA measurement. It was found that therewere six elements in the products, i.e. C, F, Si, O, N and H. The probably existed groups in poly-mers wer investigated. By analyzing the resolved peaks of C_(1S) region in ESCA spectra, effect of thereaction conditions on degree of branching of the polymerized products and the relationship of thepolymer structure wth the mechanism of the competitive ablation and polymerization process werestudied. In addition, polymer deposition process occurring in glow discharge was discussed.     

聚苯胺尿酸酶电极性能的研究

依据pH对聚苯胺尿酸酶电极最大响应电流的影响, logim～pH图表明尿酸酶电极的催化活性只与其电离基团的碱性形式有关. 扫描电镜的结果表明, 聚苯胺尿酸酶电极的稳定性与其制备方法有关. 电化学法固定的尿酸酶电极具有高的稳定性.