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1.
利用安卓智能手机的CMOS传感器并配合安卓手机软件Color Grab来获取不同编号试管中FeCl3溶液的L*,a*,b*值,并将相应数据导入到智能手机的WPS Office中处理后得到相应的色差值,通过比较色差值大小来探究浓度对化学平衡的影响,取得了良好的效果。 相似文献
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为定量识别溶液间歇结晶过程中的成核和生长阶段,基于晶粒数目和粒度的变化对粒度分布(CSD)的二阶和三阶矩量影响程度的不同,定义并关联了无因次变量K和K*.添加晶种KNO3-H2O溶液结晶过程模拟计算的结果表明,K和K*值均呈先降后升的变化趋势,成核时单调下降,生长过程中单调上升;且K与K*值较接近.测定了KNO3-H2O溶液自发成核结晶过程中溶液浓度和透光率的变化,用K*判据定量识别出成核阶段和生长阶段,并与晶体线性生长速率模型检验的结果相吻合.K值的计算依赖于CSD和结晶动力学参数,而K*作为成核和生长阶段的模型判据,由实验测定的溶液浓度和透光率计算得到. 相似文献
4.
《化学分析计量》2008,17(3):47
本发明提供一种用于检测有机汞化合物的方法,包括以下步骤:首先将待测样品中的有机汞萃取出来,并在高效液相色谱中进行分离,高效液相色谱中的流动相包括2一巯基乙醇、低级脂肪酸和低级脂肪酸盐中的一种或者几种,使色谱柱流出物在紫外灯照射下发生化学反应,将反应溶液与惰性气体进行混合,将气液混合物经气液分离器进行分离,通过原子荧光光谱仪检测分离后样品的气相做出高效液相色谱图,根据有机汞浓度和出峰面积之间的标准曲线,通过所述分离后样品的气相在高效液相色谱中的出峰面积计算出待测样品中的有机汞浓度。本发明提供了一种可以将待测样品中的多种有机汞成功进行分离检测的方法。 相似文献
5.
通过蠕变和振荡实验分别测定了部分水解聚丙烯酰胺(PHPA)水溶液的零剪切黏度(η0)和线性黏弹区储能模量(G'), 并依据其浓度依赖性得到叠加浓度(C*)和交叠浓度(C*), 考察了温度、pH值和电解质(NaCl和CaCl2)浓度的影响. 结果表明, 随着温度的升高和电解质浓度的增大, PHPA水溶液的η0及G'减小, C*和C*增大; 电解质阳离子价态越高, 溶液黏度和临界浓度的变化越显著; 而随着pH值的增大, η0及G'先增大后减小, C*和C*先减小后增大. 相似文献
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氰乙基纤维素/二甲基甲酰胺溶液在高分子浓度达到一定值C_1~*时,可以形成液晶态。随浓度的增加,各向同性溶液经过一个两相共存区而转变成为完全各向异性的体系。通过观察溶液的双折射,测定溶液的折射率和消光度,确定出了溶液的临界浓度C_1~*和C_2~*。并用观察溶液双折射的方法测定了不同浓度下溶液的相转变温度Tc,得到了该溶液的T—C相图。讨论了在该体系中液晶态的形成过程。 相似文献
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电化学DNA生物传感器定量检测根癌农杆菌终止子基因片段 总被引:4,自引:1,他引:3
通过自组装法及共价法固定单链脱氧核糖核酸(ssDNA),制备了电化学DNA生物传感器。将巯基丙酸(MPA)自组装于金电极表面形成单分子膜,再利用1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)的活化作用将ssDNA探针序列固定于金电极表面。将ssDNA修饰的电极与待测溶液中人工合成的转基因食品中常有的根癌农杆菌终止子(NOS)基因片段进行杂交,在[Fe(CN)6]3-/4-溶液中进行循环伏安和电化学阻抗谱扫描,表征ssDNA固定及杂交过程。优化了ssDNA固定条件。待测溶液中DNA浓度在1.0×10-7~1.0×10-10mol/L范围时,其浓度的对数值和ssDNA/Au电极与dsDNA/Au电极峰电流差值的变化值呈线性相关关系,相关系数为0.9822,检出限为8.1×10-11mol/L。 相似文献
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双波长吸光光度法同时测定血清中钙和镁 总被引:1,自引:1,他引:1
血清中钙和镁与人的健康密切相关,由于性质接近,又往往共存,给分析带来一定的困难.钙和镁同时测定报道不多,常用原子吸收光度法,虽灵敏可靠,但仪器昂贵.本法可同时测定血清中钙和镁,无需分离和加掩蔽剂,方法简便、快速、结果可靠.甲基百里香酚蓝(MTB)是一种优良的金属络合染料,在碱性条件下只与钙、镁离子呈色.本文利用等吸收双波长消去法,在选定的两波长处,干扰组分具有相等的吸光度,钙、镁混合物吸光度的差值△A只与待测组分的浓度成正比,由此可计算待测组分的浓度.1试验部分1.1主要仪器与试剂 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
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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
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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
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Sergey P. Verevkin Wei-Hong Peng Hans-Dieter Beckhaus Christoph Rüchardt 《Structural chemistry》1996,7(5-6):397-404
The standard enthalpies of combustion c
H
o of aliphatic diacetates1 and aromatic diacetates2 were measured calorimetrically. The enthalpies of vaporization vap
H
o or sublimation sub
H
o of1 and2 were obtained from the temperature function of the vapor pressure measured in a flow system. From f
H
o(g) of1 and2 new values of group increments for the estimation of standard enthalpies of formation of these classes of compounds were derived. The geminal interaction energy between the geminal acyloxy groups shows no anomeric stabilization.Geminal Substituent Effects, Part 12, for part 11 see Ref. 7. 相似文献
15.
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
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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
17.
G. Venkoba Rao M. Balakrishnan N. Venkatasubramanian P. V. Subramanian V. Subramanian 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):83-85
Abstract The signals for the α, β, and γ protons of pyridine exhibit a downfield shift in DMSO-d6, compared to CCl4 as solvent, the order being γ > β > α. This is attributed to an interaction between the positive end of the DMSO dipole and the lone pair of electrons on the ring nitrogen. This effect is also reflected in the faster rate of alkaline hydrolysis of ethyl isonicotinate over ethyl nicotinate and ethyl picolinate in aqueous DMSO relative to aqueous ethanol. Similar solvent effects are also observed in the pmr spectrum of pyrazine. 相似文献
18.
The protonation of leucoemeraldine in power form and in N-methylpyrrolidinone (NMP) solution by HCIO4 and HBF4 has been studied by x-ray photoelectron spectroscopy (XPS), infrared (IR), and ultraviolet (UV)-visible absorption spectroscopy. In powder form, less than 25% of the amine nitrogens can be protonated in the absence of oxygen. The effects of oxygen on the degree of protonation and the distribution of amine and imine units upon deprotonation of the salt are investigated. The degree of protonation in leuccemeraldine can be increased to about 50% with 3 M HCIO4, similar to that achievable with emeraldine base in powder form. In NMP solution, leucoemeraldine is easily oxidized by dissolved oxygen. Protonation of both leucoemeraldine and emeraldine base in NMP solutions results in metastable species which gradually undergo deprotonation. The resulting products are affected by the O2 content of the solutions. © 1993 John Wiley & Sons, Inc. 相似文献
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根据盐类水解关系式和水的离子积计算公式,建立了计算盐类水解度和水解产物离解常数的完全方程式。计算值同实验值比较,钾明矾溶液水解度平均偏差为0.6%,离解常数pK_b=11.6±0.1,水的离子积pK_w平均偏差小于0.06,从而改进了苏联的计算公式。 相似文献
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碳量子点(CQD)具有化学惰性,生物相容性和低毒性等优势,可能在能源、生物医药等领域得到广泛的应用. CQD可通过表面被聚合物(例如PEG)钝化而表现出很强的光致发光特性.在生物成像,疾病检测和药物输送中使用表面钝化后的功能化生物分子更为有效.并且碳材料由于其优异的电化学性能还展现出在催化、电子器件等许多领域广泛的应用前景.我们将对近年来碳量子点发光材料的研究进行总结,并讨论碳量子点在能源、环境和其他一些领域的应用. 相似文献