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1.
关于微量钙的测定国内外亦有不少报导,特别是随着稀土金属的广泛应用对于稀土中微量钙的测定尤为重要。例如,日本对彩色电视机用氧化钇的成分,在1970年规定其氧化钇含量最低不少于99.9%,其主要杂质钙要求小于10ppm。而到1979年,则要求氧化钇含量不少于99.99%,钙要求小于7ppm。目前对稀土氧化物中微量钙的测定大多是采用原子吸收法和火焰光度法。利用化学分析法进行测定的主要加有乙二醛缩双法(GBHA法),但此法的稳定性较差。为此,通过试验我们拟定了稀土氧化物中微量钙的偶氮胂(Ⅰ)分光光度测定法。采用在pH=9-10时,用氨水和铜试剂沉淀 相似文献
2.
照相明胶中的微量金属元素对卤化银乳剂的性能有多方面的影响,所以研究照相明胶中金属杂质的总量,以及它们的化学形态对改善乳剂质量和生产优质照相明胶具有重要意义。本文以明胶中钙的测定为例探讨了凝胶过滤─-火焰原子吸收法在研究照相明胶中金属形态的特点,并且提出了不经消化或水解而用火焰原子吸收法直接测定明胶中钙的方法。 相似文献
3.
4.
5.
孟福海 《理化检验(化学分册)》1998,(12)
铅钙锡铝合金广泛应用于全密封免维护铅蓄电池极板的生产.铅钙锡铝合金中微量钙的测定有汞分离EDTA容量法、氯化铅-铜试剂分离EDTA容量法等.本文研究了用偶氮氯膦Ⅰ(CPAⅠ)光度法测定铅钙锡铝合金中的微量钙,在测定条件下,合金元素锡、铅分别以β-偏锡酸和硫酸铅沉淀分离,共存元素用三乙醇胺、邻菲罗啉掩蔽.测定结果的准确度和精密度令人满意. 相似文献
6.
7.
原子吸收光谱法同时测定铅钙锡铝合金中钙和锡 总被引:4,自引:1,他引:4
杜颂如 《理化检验(化学分册)》2002,38(10):521-522
铅钙锡铝合金广泛用于全密封免维护铅蓄电池极板的生产。合金中微量钙的测定有汞分离EDTA容量法[1] ,氯化铅 铜试剂分离EDTA容量法[2 ] ,原子吸收光谱法[3 ] 。锡的测定通常采用邻苯二酚紫 十六烷基三甲基溴化铵吸光光度法[4 ] 。而用原子吸收光谱法测定铅钙锡铝合金中钙和锡的方法还未见报道。科研所研制生产的铅钙锡铝合金中含钙0 0 75 %~ 0 .12 % ,含锡 0 .4 %~ 0 .6 % ,含铝 0 .0 2 %~ 0 .0 3% ,余量为铅。本文用原子吸收光谱法同时测定其中的钙和锡 ,吸收波长分别为 4 2 2 .7和2 86 3nm。为了防止铅钙锡铝合金中锡水… 相似文献
8.
9.
微量硼的测定方法研究进展 总被引:5,自引:0,他引:5
综述了测定微量、痕量硼的各种方法,如分光光度法、电感耦合等离子体原子发射光谱法、电感耦合等离子体质谱法等方法的特点,并说明了其测定微量硼的应用领域.并对微量硼的测定技术进行了展望. 相似文献
10.
江秋月 《理化检验(化学分册)》2011,(5)
火焰原子吸收光谱法测定微量铅、锌、镉的报道较多,该法用于工业废水的测定,可实现连续分析,成本低、操作简单,能快速准确地得到测定结果,可及时有效地进行监控。经石灰、片碱处理后的工业废水中含高钠、钙等碱土金属、碱金属等离子,用火焰原子吸收光谱法直接测定此废水中铅、锌、镉的报道不多。 相似文献
11.
A. V. Tvardovskii A. A. Fomkin Yu. I. Tarasevich I. G. Polyakova V. V. Serpinskii I. M. Guseva 《Russian Chemical Bulletin》1992,41(6):987-991
The changes in the thermodynamic functions of the sorbents were calculated for the first time from measurements of the deformations of vermiculite during the sorption of water vapor and adsorption-calorimetric data.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Institute of Colloid Chemistry and the Chemistry of Water, Academy of Sciences of the Ukraine, 252180 Kiev. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1270–1275, June, 1992. 相似文献
12.
We have summarized results of many experimental investigations of the thermodynamics of ionization of H2O(liq.) from 0–300°C and from 1.0 atm to nearly 8000 atm. Results of these investigations (equilibrium constants, enthalpies of ionization, heat capacities, partial molal volumes, and compressibilities) have been used for a number of thermodynamic calculations. It is particularly noteworthy that it is possible to use thermal data from 0–145°C with an equilibrium constant for 25°C in calculating reasonably accurate equilibrium constants for temperatures as high as 300°C. Similarly, it is possible to use volumetric data that refer to 1.0 atm in calculating useful equilibrium constants that apply for pressures as high as 2000 atm.Much of the work reported here was done while the author was on leave at the University of Lethbridge. 相似文献
13.
Earl M. Woolley John O. Hill William K. Hannan Loren G. Hepler 《Journal of solution chemistry》1978,7(5):385-393
We have made calorimetric measurements of enthalpies of dilution of aqueous iodic acid and have used these results for evaluation of the standard enthalpy of ionization of HIO3(aq.). We have also made calorimetric measurements of enthalpies of addition of perchloric acid solution to aqueous solutions of KIO3, KNO3, NaIO3, and NaNO3 and have used these results to obtain further values for the standard enthalpy of ionization of HIO3(aq.). On the basis of all these results, we have selected Ho=–660±125 cal-mole–1 as the best available standard enthalpy of ionization of HIO3(aq.) at 298.15°K, compared to the previously accepted –2400 cal-mole–1. Using the best available K=0.157 for ionization, we also obtain Go=1097 cal-mole–1 and So=–5.9 cal-oK–1-mole–1 for ionization of HIO3(aq) at 298.15°K.On study leave from Department of Inorganic and Analytical Chemistry, LaTrobe University, Bundoora, Victoria, 3083, Australia, to University of Lethbridge.On study leave from Department of Chemistry, University of Wollongong, Wollongong, N.S.W. 2500, Australia, to University of Lethbridge. 相似文献
14.
T. P. Chusova L. N. Zelenina Yu. G. Stenin Z. I. Semenova V. A. Titov 《Russian Chemical Bulletin》2007,56(7):1313-1317
The unsaturated and saturated pressures of gallium trichloride vapor were measured by the static method with membrane-gauge
manometers in wide pressure (0.2–760 Torr) and temperature (313–1071 K) intervals. Scanning calorimetry was used to determine
the thermodynamic characteristics of GaCl3 fusion. The thermodynamic characteristics were obtained for sublimation, fusion, vaporization, and association in the vapor
of GaCl3 molecules. The enthalpies of formation and the absolute entropies of GaCl3 in the liquid and gaseous phases and Ga2Cl6 in the gaseous phase were calculated using literature data.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1266–1269, July, 2007. 相似文献
15.
锌在植物中的形态及生理作用机理研究进展 总被引:27,自引:1,他引:26
对锌在植物中的形态及锌在植物生理过程中的作用机理进行了综述和讨论,表明锌对碳水化合物代谢,蛋白质代谢,植物生长素代谢及细胞膜的功能和结构有很大影响。此外,锌与植物病害也有很大关系。 相似文献
16.
An equation for the internal pressure acting on an adsorbate in micropores was obtained on the basis of the assumption that the chemical potential of an adsorbate in micropores is equal to that in an equilibrium gas phase and using the Dubinin-Radushkevich equation. The empirical relation between the characteristic adsorption energy and the half width of pores was expressed in terms of internal pressure and diameter of adsorbate molecules. The two-dimensional pressure was calculated for micropores with plane-parallel walls, where the width of a micropore coincides with the diameter of an adsorbate molecule. The results obtained were compared with the two-dimensional pressure of a monolayer on a free planar surface for an adsorbate and adsorbent of the same nature.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1928–1930, October, 1995. 相似文献
17.
R. M. Lazorenko-Manevich A. N. Podobaev L. A. Sokolova 《Russian Journal of Electrochemistry》2007,43(1):42-50
Based on the model of spatial separation of the dissolution and passivation of hydrophilic metals, the effect of strong specific adsorption of anions on the shape of curves for the relaxation of anodic current of metals in acid solutions after switching an anodic activation pulse off is considered by using iron as an example. 相似文献
18.
W. Zielenkiewicz A. Zielenkiewicz K. L. Wierzchowski 《Journal of solution chemistry》1993,22(11):975-981
Enthalpies of solution in water H
sol
o
and enthalpies of sublimation H
sub
o
were determined for a number of crystalline derivatives of uracil: 1,6-dimethyluracil (m
2
1,6
Ura), 1,3,6-trimethyluracil (m
3
1,3,6
Ura), 6-ethyl-1,3-dimethyluracil (e6m
2
1,3
Ura), 6-propyl-1,3-dimethyluracil (pr6m
2
1,3
Ura) and 6-butyl-1,3-dimethyluracil (but6m
2
1,3
Ura). Standard enthalpies of hydration H
hydr
o
and standard enthalpies of interaction H
int
o
of the solutes with their hydration shells were calculated. The data obtained show that dependence of H
int
o
on the number of-CH2- groups of n-alkyl chain added upon substitution of diketopyrimidine ring is nonlinear. This finding is discussed in connection with results of X-ray diffraction structure determinations for the crystalline compounds. 相似文献
19.
The results of recent developments on modelling of supramolecular ordering and physicochemical properties of molecular mixtures
have been reviewed. The main attention is paid to the unified approach based on a generalized quasichemical model for a set
of thermodynamic, dielectric and optical properties of mixtures, self-organized by specific bonding. Interrelations between
thermodynamic, as well as dielectric, and optical properties of liquid mixtures, reflecting different molecular parameters,
and the characteristics of quasichemical processes are presented. Applications for thermodynamic functions of mixing, permittivity,
coefficients Rayleigh light scattering in molecular mixtures are considered. Data on thermodynamics of aggregation in mixtures
have been obtained.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Anna Zielenkiewicz Wojciech Zielenkiewicz Leonid F. Sukhodub Olga T. Glukhova Alexander B. Teplitsky Kazimierz L. Wierzchowski 《Journal of solution chemistry》1984,13(11):757-765
Enthalpies of solution in water, H
sol
o
, and of sublimation, H
subl
o
, were determined experimentally for a number of crystalline N-methyl adenines: m6Ade, m
2
6,6
Ade, m9Ade, m
2
6,9
Ade, and m
3
6,6,9
Ade. Derived standard enthalpies of hydration H
hydr
o
, were corrected for the calculated cavity terms H
cav
o
to yield enthalpies of interaction H
int
o
of the solutes with their hydration shells. The increments of H
int
o
per unit area of the water-accessible molecular surface S
B
, H
int
o
(CH3)/S
B
(CH3), for the particular methyl groups: is considered to be the net effect of the gain in the energy resulting from van der Waals' interactions and of the loss in the energy due to polar interactions upon methyl substitution. It proved to vary somewhat numerically in agreement with the theoretically predicted hydration schemes of adenine. Comparison of H
int
o
/S
B
value for adenine with those previously determined for uracil and thymine indicates that the aminopurine moiety is less hydrated than the diketopyrimidine ring. 相似文献