Showing papers by "Jilin University published in 1989"
TL;DR: The results indicate that the internal strains and fluctuations in CFP are the dominant contributions to linewidth, and the mosaic effect is negligible.
Abstract: The linewidth in the EPR spectra of ${\mathrm{Cr}}^{3+}$ ions in yttrium aluminum garnet single crystals is investigated at room temperature, and an anisotropic line broadening is observed. The characteristics of broadening resulting from the mosaic effect, internal strains, and fluctuations in the crystalline field parameter CFP are analyzed. A reasonable fit to experimental data is obtained using the hybrid model wherein the mosaic effect, internal strains, and fluctuations in CFP were considered, and the results indicate that the internal strains and fluctuations in CFP are the dominant contributions to linewidth, and the mosaic effect is negligible. The effect of the internal strains caused by impurities in the crystal on linewidth is discussed.
170 citations
TL;DR: In this article, large single crystals (500 × 80 μm) of the structure type AFI have been obtained at 170°C using a synthesis medium containing F− anions.
162 citations
01 Jan 1989
TL;DR: In this article, a yield function that describes the behavior of orthotropic sheets exhibiting planar anisotropy and subjected to plane stress conditions is proposed, which gives yield surface shapes in a three-dimensional space (two normal stresses and one shear stress) in rather good agreement with the ones based on polycrystal modeling.
Abstract: A yield function that describes the behavior of orthotropic sheets exhibiting planar anisotropy and subjected to plane stress conditions is proposed. This criterion gives yield surface shapes in a three-dimensional space (two normal stresses and one shear stress) in rather good agreement with the ones based on polycrystal modeling. Some examples are given to illustrate the necessity of such formulation.
61 citations
TL;DR: In this article, a unified treatment based on the energy partitioning is proposed for rationalizing aromaticity, reactivities and bond lengths of conjugated hydrocarbons, which can be deduced from inspecting, enumerating or summing the relative contributions of various fragments.
Abstract: The truncated expansion of a function ¦x¦ is used to obtain the total Huckel π-electron energy partitioned into various sums, in terms of moments as well as molecular fragments. The additivity is in general satisfactory for acyclic and cyclic systems, which exhibit a regularity called the generalized Huckel rule which indicates whether a fragment plays the role of stabilization or of destabilization. A unified treatment based on the energy partitioning is proposed for rationalizing aromaticity, reactivities and bond lengths of conjugated hydrocarbons. The relationships between molecular properties and topology can be deduced from inspecting, enumerating or summing the relative contributions of various fragments.
46 citations
TL;DR: In this article, the 2000 evaluation of A = 52 (2000Hu06) has been revised using experimental decay and reaction data, together with adopted level and transition properties, and these data are summarized and presented.
45 citations
TL;DR: Analyses of the combined sample of Beijing and Jilin schoolchildren indicated that the only-child advantages in achievement were found among children from urban families, not rural peasant families.
Abstract: The physical, achievement, and personality characteristics of Chinese schoolchildren are evaluated. The results of two surveys of Chinese schoolchildren, conducted in Beijing and Jilin Province, are presented. In the Beijing sample, the differences between only children and others were small but statistically significant, with the only children having higher scores in achievement and physical size. In the Jilin Province sample, the differences between only children and others were also small but significant. These differences were found entirely in physical characteristics, with only children being smaller, perhaps because the only children in the Jilin sample were much younger than the non-only children. Analyses of the combined sample of Beijing and Jilin schoolchildren indicated that the only-child advantages in achievement were found among children from urban families, not rural peasant families. While significant differences in height and weight were found in all three samples, none of the results indicated a significant difference in the proportion of body fat. None of the analyses indicated that only children had undesirable personalities, as judged by teachers and mothers.
43 citations
TL;DR: In this paper, the expressions for the effective stresses and the effective strain rates for all five special cases (one of them proposed by Hosford) of Hill's yield theory for sheet metal forming are presented.
42 citations
TL;DR: In this paper, the formation conditions exerted an influence over the molecular aggregation and the crystallization behaviors of the blend films and block copolymers which were examined by X-ray diffractometry and DSC analysis.
Abstract: Polymer blends of PEEK with PES were prepared by the solution blending method. Copolymers composed of PEEK and PES components were synthesized from these oligomers. The formation conditions exerted an influence over the molecular aggregation and the crystallization behaviors of the blend films and block copolymers which were examined by X-ray diffractometry and DSC analysis. As a result, phase-separation in the blend films was found when the formation temperature was high. The blend films formed at 340°C, quenched and annealed at 180°C, exhibited the same crystallization behavior as those of PEEK. In the case of the blend films formed at 300°C, the annealing of the films at 250°C was required to crystallize the blend films. The Tg of a copolymer with a PEEK component content of more than 50% tends to shift toward a higher temperature than the Tg of PEEK itself, and the Tm of the copolymer toward a lower temperature than that of PEEK ist.
Rontgendiffraktometrische Untersuchungen und DSC-Messungen an Blend-Filmen, die aus Losungen von PEEK und PES hergestellt wurden, zeigen eine Phasenseparation bei den Filmen, die bei 340°C hergestellt wurden. Das Kristallisationsverhalten von Filmen, die bei 340°C hergestellt, anschliesend abgeschreckt und bei 180°C getempert wurden, ist identisch mit dem von PEEK. Filme, die bei 300°C hergestellt wurden, kristallisierten erst durch Tempern bei 250°C. Blockcopolymere, die aus Oligomeren von PEEK und PES erhalten wurden, unterscheiden sich in dieser Hinsicht von Blends der gleichen Zusammensetzung. Die Glastemperatur von Copolymeren mit einem PEEK-Gehalt von mehr als 50% liegt hoher als die von PEEK selbst, wahrend der Schmelzpunkt dieser Copolymeren niedriger als der von PEEK ist.
38 citations
TL;DR: In this article, the process of H2S diffusion into Langmuir-Blodgett (LB) films of copper stearate and the formation of layers of copper sulphide with semiconducting properties were studied by X-ray photoelectron spectroscopy measurements.
37 citations
TL;DR: Deep-level impurity analysis for p-n junctions of bipolar transistors from g-r noise is less developed than for homogeneous materials as discussed by the authors, and the features of g r noise associated with a p n junction have been elucidated.
Abstract: Deep-level impurity analysis for p-n junctions of bipolar transistors from g-r noise is less developed than for homogeneous materials In the present study we attempt to elucidate: 1 1 The features of g-r noise associated with a p-n junction 2 2 A new method to separate g-r noise, and experimental results 3 3 Deep-level impurity analysis for p-n junctions of bipolar transistors By doing low-frequency noise measurements and g-r noise separation at room temperature, evidence for five g-r noise components in a p-n junction of a bipolar transistor was discovered The region of the corner frequencies is 05 Hz–100 kHz, and five distinct deep-levels of impurities in the p-n junction are suggested
35 citations
TL;DR: Two algorithms for solving sparse nonlinear systems of equations with some promise of being very effective in practice are presented: the CM-successive column correction algorithm and a modified CM- successive column Correction algorithm.
Abstract: This paper presents two algorithms for solving sparse nonlinear systems of equations: the CM-successive column correction algorithm and a modified CM-successive column correction algorithm. Aq-superlinear convergence theorem and anr-convergence order estimate are given for both algorithms. Some numerical results and the detailed comparisons with some previously established algorithms show that the new algorithms have some promise of being very effective in practice.
TL;DR: The polymer blends obtained by the solution blending method show a type of compatible polymer blends as discussed by the authors, but those by compression molding above the melting point of the polyetheretherketon (PEEK) show a phase separation in dynamic viscoelastic behavior.
Abstract: The polymer blends obtained by the solution blending method show a type of compatible polymer blends. The samples obtained by compression molding the polymer blends below the melting point of the polyetheretherketon (PEEK) exhibit dynamic viscoelastic behavior characteristic of compatible polymer blends, but those by compression molding above the melting point of the PEEK show a phase separation in dynamic viscoelastic behavior.
Die aus Losung hergestellten Polymermischungen zeigen den Typus der vollmischbaren Polymerlegierungen. Proben, die durch Formpressen der Polymermischungen unterhalb des Schmelzpunkts von Polyetheretherketon (PEEK) erhallten wurden, zeigen ein fur mischbare Polymerlegierungen typisches viskoelastisches Verhalten. Hingegen zeigt sich bei Mischungen, die oberhalb des Schmelzpunktes von PEEK verprest wurden, im dynamisch-viskoelastischen Verhalten eine Phasentrennung.
TL;DR: It is demonstrated that one can hold the modulation frequency and amplitude fixed while varying the cavity detuning to change the resonant response of the laser to modulation, and thereby one can extract the relaxation oscillation frequency and the damping rate of those oscillations.
Abstract: We consider the small-signal response of a rate-equation laser to modulation of the laser cavity length. To avoid nonlinear resonances in modulators and power supplies, we demonstrate that one can hold the modulation frequency and amplitude fixed while varying the cavity detuning to change the resonant response of the laser to modulation, and thereby one can extract the relaxation oscillation frequency and the damping rate of those oscillations. This technique permits a careful study of the relaxation parameters of the laser that govern small oscillations and thereby permits discrimination among several different models recently proposed to describe ${\mathrm{CO}}_{2}$ laser dynamics. We demonstrate this method of analysis by applying it to such a laser experimentally with the result that the simple rate-equation model is shown to fail while the more complex vibro-rotational model satisfactorily describes the results.
TL;DR: In this paper, a general and efficient technique is developed for the evaluation of the integrals with various orders of singularity, such as occur in the three-dimensional boundary element method (BEM).
Abstract: A general and efficient technique is developed for the evaluation of the integrals with various orders of singularity, such as occur in the three-dimensional boundary element method (BEM). Generalized (extended) triangle, tetrahedron polar co-ordinate mappings together with two conditions are used to remove the singularity of the integrals, and to evaluate the corresponding non-singular ones in a new numerical space. Triangle and tetrahedron polar co-ordinates in Reference 1 are proved to be a special case of the generalized ones in this paper. With the developed idea, boundary element results converge rapidly towards the analytical solutions for the strongly singular integrals evaluated directly, and the analytical solutions can be gained in principle, even when employing higher order, triangular boundary elements and tetrahedral cells. The generality and practicability of the method are demonstrated in the case of higher order elements, discontinuous elements and large engineering problems.
TL;DR: Ferroaluminophosphate number 5 molecular sieve (FAPO-5) was synthesized from clear homogeneous solutions as discussed by the authors, which exhibits higher catalytic activity and selectivity for the ethylbenzene dehydrogenation, compared to those of AlPO 4 -5 and FAPSO-5.
Abstract: Ferroaluminophosphate number 5 molecular sieve (FAPO-5) was hydrothermally synthesized from clear homogeneous solutions. EPR, Mossbauer, XPS and electron probe microanalysis (EPMA) investigations evidence that iron is only substituted for aluminum but not for phosphorus atoms. The distribution of iron atoms in the sample is rich in the center and both Fe(III) and Fe(II) exist in the FAPO-5 crystals. FAPO-5 exhibits higher catalytic activity and selectivity for the ethylbenzene dehydrogenation, compared to those of AlPO 4 -5 and FAPSO-5.
TL;DR: In this article, the orbital energy function |χ| is expanded in terms of Chebychev polynomials, and a formula has been derived for each coefficient in the polynomial.
TL;DR: Two different techniques, Doppler-free saturation spectroscopy on a hollow-cathode discharge and fluorescence Spectroscopy (FES) on a collimated atomic beam produced from a hollow cathode discharge, have been used for high-resolution laser-spectroscopy measurements on the 3d10 4p and 5p states in neutral copper.
Abstract: Two different techniques, Doppler-free saturation spectroscopy on a hollow-cathode discharge and fluorescence spectroscopy on a collimated atomic beam produced from a hollow-cathode discharge, have been used for high-resolution laser-spectroscopy measurements on the 3d10 4p and 5p states in neutral Copper. The relative merits of the two techniques are discussed.
TL;DR: In this paper, the growth of the single crystals was investigated by means of Si NMR and TMS-GC methods, and precise atom positions were determined by X-ray structure analysis on the crystals.
Abstract: B-, Ti MFI-type zeolite single crystals known as Borozeosilite and Titanozeosilite were synthesized by hydrothermal crystallization in a non-alkaline medium in the presence of fluoride. The growth of the single crystals was investigated by means of Si NMR and TMS-GC methods. X-ray structure analysis was performed on the crystals, and precise atom positions were determined. The cell parameters are a=19.976, b=19.843, c=13.339 and a=20.046, b=19.950, c=13.405A for Borozeosilite and Titanozeosilite, respectively, which corresponds to isomorphous substitution of silicon by boron or titanium in the zeolite framework.
TL;DR: In this paper, two novel inclusion compounds similar to AlPO n− 4 or GaPO n − 4 were synthesized hydrothermally and characterized with X-ray powder diffraction, IR spectra, and thermal analyses.
TL;DR: In this paper, the spin reorientation temperature and the magnetic anisotropy field (H a ) of Nd 2 (Fe 13 M)B compounds (M = Ga, Si, Al).
TL;DR: In this paper, the surface photovoltage spectra of two supramolecular films with space in the lipid chain were measured for the first time using the LB technique and it was found that only the first CuTsPc monolayer adjacent to the semiconductor plays a key role in the light-induced interfacial charge transfer.
TL;DR: In this article, the values of the R-Fe exchange field H ex and averaged over f and g sites CEF parameters A nm in R 2 Fe 14 B compounds (R = Tb, Dy, Ho, Er and Tm) are evaluated by fit of calculation with a series of experiments.
TL;DR: In this article, a pressure-induced phase transition of anatase was observed at pressure above 7.1 GPa in the hydrostatic environment using a 4 : 1 mixture of methanol and ethanol as pressure medium.
Abstract: The Raman spectra of anatase have been investigated under pressure up to 17 GPa and at room temperature. The pressure dependences of the Raman active modes are reported. A pressure-induced phase transition of anatase is observed at pressure above 7.1 GPa in the hydrostatic environment using a 4 :1 mixture of methanol and ethanol as pressure medium. On the basis of in situ powder X-ray diffraction data and comparison of the Raman spectrum of the high-pressure modification with that of TiO2, -II (a-PbO2, -type structure), it is evident that at high pressure anatase transforms irreversibly to Ti PbO2, -II.
TL;DR: In this paper, a series of SAPO-5 samples with different numbers of silicon atoms are investigated by chemical analysis, XRD and CP/MAS NMR, and the results indicate that the lines at about −102 and −110 ppm observed in the 29Si NMR spectra of the SAPO5 samples are due to the non-framework silicon phase which is structurally similar to the synthesis gel.
TL;DR: In this article, the effects of yield function shape on bulging deformation were investigated and it was found that these effects can be expressed by two characteristic parameters, α and β Bulging pressure is found to increase linearly as α increases and the uniformity of strain distribution decreases as β increases.
01 Jan 1989
TL;DR: In this paper, a method for the transition metal compound, by which a number of complex structures of several compounds have been calculated and some results in agreementwith the experimental values obtained.
Abstract: Based on the empirital electron theory of solids and molecules and the treatment of thecrystal cohesive energy of alkali metal, alkaline-earth metal and transition metal, this paperpresents a calculation method for the transition metal compound, by which a number ofcomplex structures of several compounds have been calculated and some results in agreementwith the experimental values obtained.
01 May 1989-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, both Swift's diffuse instability and Hill's localized instability theories are developed as models enabling the descriptions of both diffuse and localized necking processes, which include the classical instability criteria of Swift and Hill as special cases.
Abstract: In this paper, both Swift's diffuse instability and Hill's localized instability theories are developed as models enabling the descriptions of both diffuse and localized necking processes, which include the classical instability criteria of Swift and Hill as special cases.
TL;DR: In this paper, a cubane-like skeleton of the cluster Mo 2 Fe 2 S 4 (S 2 CNEt 2 ) 5 has been obtained from the reaction system containing (NH 4 ) 2 MoS 4, FeCl 3, NaS 2 CoNt 2, PhSH and NaOCH 3.
TL;DR: A general method of solving Schr\"odinger equations for systems with a slowly (not necessarily extremely slowly) changing Hamiltonian is proposed and its zeroth-order approximation gives the improved adiabatic theorem.
Abstract: A general method of solving Schr\"odinger equations for systems with a slowly (not necessarily extremely slowly) changing Hamiltonian is proposed. Its zeroth-order approximation gives the improved adiabatic theorem by Berry [Proc. R. Soc. London, Ser. A 392, 45 (1984)]. It shows how transitions between different energy levels occur when the Hamiltonian changes less slowly. Selection rules for such transitions are discussed.
TL;DR: In this paper, the dynamic NMR (DNMR) of intramolecular acetate scramblings that occur in Ca(II)-, Sr(II), Ba(II) and La(III)-cyclohexanediaminetetraacetate complexes was studied.
Abstract: The dynamic NMR (DNMR) of the intramolecular acetate scramblings that occur in Ca(II)-, Sr(II)–, Ba(II)– and La(III)–cyclohexanediaminetetraacetate complexes has been studied. The working temperature range was extended to 430 K by using a sealed thick-walled capillary sample tube and new DNMR phenomena were thus observed. Information on activation energy, enthalpy, entropy and the free energy of nitrogen inversion of the chelates was obtained by computer analysis.