石墨炉原子吸收光谱法测定施用稀土微肥后魔芋中的镉、铅和铬

为了解施用稀土微肥是否对魔芋中的重金属有缓解富集作用,通过对HNO3-HClO4及HNO3-H2O2湿法消解和干法灰化3种样品前处理方式的选择以及石墨炉原子吸收升温方式的优化,建立了灵敏度高、准确性好的GFAAS法,测定魔芋中镉、铅和铬的含量.运用本法对施用稀土微肥后魔芋中上述元素的含量进行测定,结果表明,稀土微肥能够减缓镉、铅和铬重金属元素在魔芋中的积累.     

华北模拟实验块地大气、降水、地表径流和土壤中的稀土浓度分布及施用农用稀土的影响

通过模拟实验块地，初步研究了在一个土壤生态系统中稀土的浓度分布以及施用稀土微肥的影响。结果表明：降水、地表径流水溶液中的稀土浓度均为μｇ／Ｌ量级（０１～１２μｇ／Ｌ），降水中的稀土主要来源于附近地表土壤。大气中的稀土含量随粒径分布有所不同，粒径越小含量越低，且其来源主要是附近的土壤，水可溶性的硝酸稀土微肥在施用后很快转化为水不溶性形态，施加稀土前后实验组表层土壤中稀土含量基本相同。与对照组相比，施加的稀土微肥对地表径流水溶性和悬浮物稀土浓度未产生明显影响。     

华北模拟实验块地大气,降水,地表径流和土壤中的稀土浓度分布及施…

通过模拟实验块地，初步了在一个土壤生态系统中稀土的浓度分布以及施用稀土微肥的影响，结果表明：降水、地表径流水溶液中的稀土浓度均为μｇ／Ｌ量级，降水中的稀土主要来源于附近地表土壤。大气中的稀土含量随粒径２有所不同，粒径越小一越低，且其来源主要是附近的水可溶性的硝酸稀土微肥在施用后很快转化为水不溶性形态，施加稀土前后实验组表层土壤中稀土含量基本相同，与对照组相比，施加的稀土微肥对地表径流水溶性和悬浮的     

农用稀土施用量、宽窄行配置对鲜食糯玉米产量构成因素及品质的影响

通过田间小区试验,研究了不同稀土施用量、不同宽窄行配置对鲜食糯玉米产量、产量构成要素和品质的影响。结果表明:农用稀土施用量为200 mg.kg-1时,宽窄行配置为70+50 cm时,吐丝进程最快;皮渣比率、可溶性糖含量、籽粒粗淀粉含量、植株全氮含量均比较小;蒸煮品质即风味、气味,糯性等表现最佳。小花总数、受精小花数、结粒数随着农用稀土施用量增加而减少,且宽窄行配置70+50 cm时,为最大。在农用稀土施用量为600 mg.kg-1时,宽窄行配置60+60 cm时,鲜穗产量为最高,达11883.9 kg.hm-2,在农用稀土施用量为800 mg.kg-1时,宽窄行配置70+50 cm时,鲜穗产量为最低,为9355.8 kg.hm-2。     

La3+提高拟南芥耐旱能力研究

稀土元素有着广泛的生物学效应,稀土作为微肥在我国农业广泛使用.然而,稀土对植物抗旱性影响的研究很少.以模式植物拟南芥为材料,研究了不同浓度的镧(La3+)对植物根生长以及对植物耐旱能力的影响.结果表明,10和100 μmol ·L-1的La3能显著促进根生长,提高植物耐旱能力;1μmol·L-1La3+没有明显促进根生长,但显著提高了植物耐旱能力;1和10 mmol·L-1的La3+不能促进根生长,同时还降低了植物耐旱能力.该结果提示,稀土农用过程中要重视剂量的使用,同时避免带来生态环境问题.     

大豆中稀土元素分配规律研究

研究了大豆中稀土元素（La、Ce、Nd、Y、Gd）的含量分布规律。结果表明：大豆各部位稀土含量分布一般规律为：根＞茎＞夹壳＞夹果;大豆在生长不同期吸收稀土的能力大小为：幼苗期＞分枝期＞成熟期。总之,稀土元素在大豆中不易迁移,主要集中在根部,果实中含量甚微,因而施用稀土微肥,不会影响食用粮食的安全问题。     

龙眼叶片活性氧代谢和抗氧化系统对La3+的响应

以一年生龙眼小苗为材料,研究了La3+对龙眼叶片活性氧代谢和抗氧化系统的影响,探讨La3+提高植物抗逆境能力作用机制。龙眼小苗喷施10,20,30,40,50 mg.L-1的La(NO3)3两次,通过检测叶片的自由基含量、抗氧化酶活性和抗氧化物质含量来分析La3+提高龙眼抗氧化的作用。结果表明:20～30 mg.L-1La3+处理可明显清除龙眼叶片的.O2-和H2O2,减少MDA生成量;显著提高叶片SOD和CAT酶活性,降低POD活性,提高AsA-GSH循环运行效率及相关代谢酶APX,MDAR,DHAR和GR的活性,保证AsA和GSH再生,显示稀土离子La3+对龙眼抗性具有显著的正调节作用。     

“常乐”稀土微肥对糯玉米冠层光合特性及产量的影响

在50,100,200,400,600,800 mg.kg-1浓度的"常乐"稀土微肥条件下,研究了其对糯玉米冠层叶的叶绿素含量、荧光参数及产量构成因素的影响。结果表明,糯玉米授粉后棒三叶的叶绿素含量及荧光参数的增大幅度明显随常乐处理剂量的增大而呈规律性变化:即T1至T4处理不仅叶绿素含量呈现明显增大趋势,而当处理浓度为600 mg.L-1时叶绿素含量则表现下降,而且PSII的潜在活性(FV/F0)、光化学最大效率(FV/Fm)和量子效率(ΦPSII)亦表现出相似的规律;但PSII的光化学猝灭系数(qP)则随常乐处理浓度的增大,表现出先增后减的规律,优势明显并具有较高的光合速率,尤其是400 mg.kg-1光合功能强,籽粒产量最高达16320.0 kg.hm-2。另外,授粉后的生育期也对鲜食糯玉米冠层叶绿素荧光参数具有明显正效应,在授粉后16 d时,不同浓度"常乐"稀土微肥处理的鲜食糯玉米不同叶位叶光合速率最大。     

天津沿海潮间带沉积物中稀土元素的地球化学特征

研究了天津沿海潮间带沉积物中稀土元素(REE)的地球化学特性以及污染条件下稀土元素的环境行为特征,通过稀土分布模式特征探讨了潮间带沉积物的物质来源.结果表明(1)潮间带沉积物中14种稀土含量总和的均值为164.5mg@kg-1,但各岸段又有不同.大致以海河口为界,北部明显高于南部,均值分别为182和150mg@kg-1,均明显高于海洋沉积物稀土含量;(2)海岸带沉积物稀土形态分布特征是自北向南残渣态比例逐渐下降,铁锰氧化物态和有机结合态比例逐渐增高,与黄河、长江等大河相比,残渣态和碳酸盐态比例都显著偏低;(3)稀土元素分布模式均为轻稀土富集、铕中度亏损型,与沿海排污河及内陆大河沉积物稀土分布模式相似,而与海洋大陆架沉积物稀土分布模式有显著差别.     

稀土与细胞,器官,组织的作用及其生理效应

稀土与细胞、器官、组织的作用及其生理效应杨频，魏春英（山西大学分子科学研究所，太原，０３０００６）我国稀土贮量占世界第一位，稀土微肥已被大面积使用，稀土已进入植物，如在玉米大豆中，稀土含量为１０（－８）～１０（－１０）ｇ／ｇ［１］。随着稀土的广泛应用...     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。