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991.
992.
Studies of temperature dependences of ac magnetization were carried out for a superconducting lead-porous glass nanocomposite. Double peaks were found on the imaginary part of ac magnetization which were accompanied with double steps on the real part. The lower-temperature anomalies in ac magnetization differed noticeably when they were obtained upon cooling and warming. The double peaks were treated as two phase transitions in the vortex system: the liquid-solid transition which occurs close to the onset of superconductivity and solid-solid one which is triggered by superconductivity in confined lead islands. 相似文献
993.
构造了S^1上S^3|H-丛的所有复结构的模空间,其中丛的转换函数u:s^3/H→S^3/H是S^3/H的一个对合,HU(2),H为有限群且在S^3/H上的作用是自由的。真不连续的。 相似文献
994.
995.
Tijen Tanyalcin Diler Aslan Yusuf Kurtulmus Nalan Gökalp Kamil Kumanlioğlu 《Accreditation and quality assurance》2000,5(9):383-387
In this study the reference intervals for folate and vitamin B12 were estimated according to the National Committee for Clinical Laboratory Standards Approved Guideline C28-A and International
Federation of Clinical Chemistry recommendations. The study included 155 women and 124 men between ages 18–40. The health
status was confirmed by history, physical examination and a questionnaire. The central 95% reference intervals of serum folate
and vitamin B12 for women, determined non-parametrically, were found to be 3.9–18.1 ng/ml and 101–666.7 pg/ml, respectively.
The reference values of serum folate and vitamin B12 for men were also found to be 2,5–17.6 ng/ml and 100–699.57 pg/ml, respectively.
We did not observe subclass differences between females and males.
Received: 15 April 2000 · Accepted: 15 April 2000 相似文献
996.
C. Raghu Indranil Rudra Diptiman Sen S. Ramasesha 《Journal of Chemical Sciences》2001,113(5-6):459-486
One of the fascinating fields of study in magnetism in recent years has been the study of quantum phenomena in nanosystems.
While semiconductor structures have provided paradigms of nanosystems from the stand point of electronic phenomena, the synthesis
of high nuclearity transition metal complexes have provided examples of nano magnets. The range and diversity of the properties
exhibited by these systems rivals its electronic counterparts. Qualitative understanding of these phenomena requires only
a knowledge of basic physics, but quantitative study throws up many challenges that are similar to those encountered in the
study of correlated electronic systems. In this article, a brief overview of the current trends in this area are highlighted
and some of the efforts of our group in developing a quantitative understanding of this field are outlined. 相似文献
997.
The objective of this work is to determine the maximum stretch of the C–C bond before it misses the character of single bond, employing both the Atoms in Molecules (AIM) and Electron Localization Function (ELF) methods. It was concluded that C–C distances up to 2.0 Å could be considered single bonds. 相似文献
998.
999.
The values of the gas-chromatographic indicator reflecting the capacity of analytes for self-association in pure liquids,
δT
b.p., were estimated for C1–C9 and C11
n-alkanols by capillary gas chromatography on a nonpolar stationary phase under isothermal conditions. The δT
b.p. values ofn-alkanols, found as the difference between the boiling points measured directly and those calculated from GC data, are correlated
with thermodynamic characteristics of the formation ofn-alkanol associates in pure liquids. Usingn-alkanols as analytes with insignificant temperature increments of the retention indices, it was shown that the δT
b.p. values can be determined under conditions used in gas chromatography with temperature programming. In this way a single chromatographic
run can be used to compare the capacities for self-association of analytes boiling over a wide temperature range. The C2–C9
n-alkanethiols, which are not associated in neat liquids, have negative δT
b.p. values. An interpretation of this finding is proposed.
Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 315–318 February, 2000. 相似文献
1000.
O. Mondain-Monval J.C. Dedieu T. Gulik-Krzywicki P. Poulin 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,12(2):167-170
The role of surface energy in the behavior of colloidal particles in liquid crystalline phases is investigated. When the surface
energy dominates, a hedgehog defect is formed and, according to an electrostatic analogy, the distortions around the particles
exhibit a dipolar character. By contrast, for weaker anchoring, the configuration becomes quadrupolar as evidenced by the
structure of latex clusters in lyotropic systems and the observation of defects reminiscent of Saturn rings in thermotropic
systems.
Received 21 June 1999 相似文献