SigmaPlot软件在化学实验数据处理中的应用

SigmaPlot是功能强大的数据分析和科学绘图软件,通过实例,初步介绍了SigmaPlot处理实验数据的方法和结果。结果表明,用SigmaPlot对实验数据作处理,解决了化学实验中数据多、处理麻烦、手工作图误差大等问题,使处理过程简单、快捷,提高了效率和准确性。     

Constitutive relations of damaged viscoelastic materials including chemical reaction

Chemical reactions and damage are important in the study of constitutive laws for some engineering materials, such as polymers and their composites. In this paper, we have derived a general form of constitutive laws for damaged viscoelastic materials including chemical reactions by the use of irreversible thermodynamics and the Hamilton principle. The experimental results have been obtained for ageing solid propellant materials and compared with the theoretical model. Good agreement is found between the theory and experiments.The project supported by National Natural Science Foundation of China.     

1H, 13C and 15N NMR chemical shifts of substituted pyrazolo[1,5‐a]pyrimidines

¹H, ¹³C and ¹⁵N NMR chemical shifts of 10 substituted pyrazolo[1,5‐a]pyrimidines were assigned based on DQF ¹H, ¹H COSY, PFG ¹H, ¹³C HMQC and PFG ¹H,X (X = ¹³C and ¹⁵N) HMBC experiments and on literature data. Copyright © 2002 John Wiley & Sons, Ltd.     

致癌性胺离子反应过程中电荷和化学位移的计算

应用原子-键电负性均衡方法中的σπ模型(ABEEMσπ)计算了由致癌性胺离子所参与的反应过程中的电荷分布,所计算出的电荷分布可以和从头算很好的相关联,并且所需要的时间也大大的缩短;同时应用从头计算程序计算致癌性胺离子反应过程中的NMR化学位移.结果表明,在反应过程中电荷的变化和NMR化学位移的变化有很好的对应关系.     

Durability of pultruded glass-fiber-reinforced polyester profiles for structural applications

Results of an experimental research into the physical, chemical, mechanical, and aesthetical changes suffered by pultruded glass-fiber-reinforced polyester profiles during their testing for accelerated aging under the action of moisture, temperature, and ultraviolet (UV) radiation are presented. The profiles were submitted to the influence of four different exposure environments: (i) in an immersion chamber, (ii) in a condensation chamber, (iii) in a QUV accelerated weathering apparatus, and (iv) in a xenon-arc accelerated weathering apparatus. The results obtained were analyzed regarding the changes in their weight, sorption ability, tensile and flexural strength characteristics, color, and gloss; the chemical changes were investigated by means of Fourier-transform infrared spectroscopy. Considerable chromatic changes were observed, especially owing to the UV radiation. Although some reduction in the mechanical properties was observed, particularly in the immersion and condensation chambers, the durability tests proved a generally good behavior of this material under the aggressive conditions considered. Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 4, pp. 463–474, July–August, 2006.     

Electronic and spatial structure of five-membered oxygen-or sulfur-containing cyclic phosphorus and arsenic compounds based on quantum-chemical calculations

We have carried out nonempirical quantum-chemical calculations for five-membered heterocyclic molecules containing O or S atoms and also P or As atoms in the ring, using RHF/6-31G(d) and MP2/6-31G(d) methods with full optimization of their geometry. We have studied their electronic and spatial structure and the characteristics of the interaction between atoms in the molecules. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 629–634 April, 2006.     

Relativistic and many-body effects in K, L, and M shell ionization energy for elements with and the determination of the 1s Lamb shift for heavy elements

We report on a calculation of K, L and M inner-shell ionization energy in atoms with atomic numbers in the range . Many-body effects are evaluated for all n =1, 2, and 3 hole states. Those include correlation and effects due to the auto-ionizing nature of the hole states (Auger shift). For high Z we add recent corrected nuclear polarization, and several second-order vacuum polarization corrections. K and L ionization energies are compared with experimental X-ray absorption edges measurements. Excellent agreement with rare gazes and metal vapor measurements is found. We also compare our calculations with X-ray transition energies for all K and L lines that involve K, L and M holes. Finally we use K X-ray lines to deduce an hydrogenlike 1 s Lamb shift for several heavy elements, with far better accuracy than has been obtained by direct measurements of hydrogenlike ions. Received: 25 February 1998 / Accepted: 31 March 1998     

PERIODIC REACTION AND TURBULENCE OF CHEMICAL BRUSSELATOR

In this paper,we discuss the reaction model of tri-molecules and the exi- stence of periodic reaction under certain original density conditions of two ob- jects without diffusion phenomena.We prove that the periodic reaction exhibit some chemical phenomena that violate the second law of thermo-mechanics. Finally,we research similar properties and phenomena concerning Belousov- Zhabotinsky reaction model.     

Triterpenoids from Astragalus Plants

Advances in the chemistry of Astragalus triterpenoids based on worldwide literature appearing mainly after 1988 were reviewed. The review was dedicated to the memory of Professor N. K. Abubakirov.     

Would Introductory Chemistry Courses Work Better with a New Philosophical Basis?

One of the main functions that introductory chemistry courses havefulfilled during the past century has been to provide evidence for the generalvalidity of 'the atomic hypothesis.' A second function has been to demonstratethat an analytical approach has wide applicability in rationalizing many kindsof phenomena. Following R.G. Collingwood, these two functions can be recognizedas related to a philosophical 'cosmology' (worldview, weltanshauung) thatbecame dominant in the late Renaissance. Recent developments in many areasof science, and in chemistry, have emphasized the central importance of understandingsynthetic, developmental, and evolutionary aspects of nature. This paperargues that these scientific developments, and changes in other aspects of culture,amount to a widespread shift to an alternative cosmology, a quite different generalworldview. To the extent that this is the case, introductory chemistry coursesought to be changed in fundamental ways. Rather than having a main focus onanalysis to microscopic components, introductory chemistry instruction shouldemphasize current scientific understanding of the (synthetic) evolutionary originsof the present world. This altered approach would provide good preparation forfuture professional work, while also making better contact with the perceivedconcerns of students.