Thiacalix4arenes mono-, 1,3-di-, tri-, and tetrasubstituted at the lower rim, including those containing different substituents, were synthesized by the method based on the ability of the phenacyl ...moiety to serve as the protecting group, as well as to be involved in transalkylation.
We present the results of a search for high-energy neutrinos with the Baikal underwater Cherenkov detector NT-96. An upper limit on the diffuse flux of
ν
e
+
ν
μ
+
ν
μ
̄
of
E
2Φ
ν
(E)<1.4×10
−5
cm
−2
...s
−1
sr
−1
GeV
within neutrino energy range
10
4–10
7
GeV
is obtained, assuming an
E
−2 behavior of the neutrino spectrum.
The reflection spectra were obtained for three differently colored zones with different chemical compositions (Table 2). The lightest zone is characterized by the maximum values of reflections, while ...the darkest zone with the highest As contents shows the lowest values. The isomorphic substitution of Bi and Si for Pb and As, respectively, shows no effect on the reflection curves.They are always subparallel, with the maximum peak of the mineral within 560620 nm.
A number of experimental methods have been applied to study the kinetics of high-pressure solid-state amorphization for some covalent crystals (Si, Ge and GaSb), molecular crystals, C60 and ionic ...oxides (stishovite and H2O), as well as the amorphous-to-amorphous transitions for H2O and GeO2. The low activation energy for the stishovite → a-SiO2 transition and appreciable variation of kinetic characteristics in the covalent compounds, depending on the number of components, were observed. Using high-pressure solid-state amorphization it is possible to obtain amorphous tetrahedral carbon by compression of C60-crystals. We have shown that the P-T kinetic lines for amorphization smoothly convert to the ordinary crystal-to-crystal hysteresis lines at high temperatures. For the first time experimental evidence for elastic softening in the vicinity of crystal-to-amorphous and amorphous-to-amorphous transitions is presented. The pressure and time dependence of the a-GeO2 volume changes were measured during the high-pressure transformation. The transition occurs in a wide pressure region and the volume has logarithmic time dependence at a fixed pressure. Comparison of the solid-state amorphization and amorphous-to-amorphous transition is made.
A pectic polysaccharide named comaruman (CP) was extracted from the aerial part of
Comarum palustre with 0.7% aqueous ammonium oxalate and subsequent precipitation with ethanol. Oral administration ...of comaruman (5–100 mg/kg) was found to reduce a paw edema observed 24 h after injection of 2% formalin in mice. A fraction of comaruman (CP-H9) exhibited a similar antiinflammatory activity. Comaruman, CP deprived of lipid, CP purified by proteins and CP fractions obtained with acidic hydrolysis inhibit spontaneous and phorbol-12-myristate-13-acetate-activated adhesion of peritoneal leukocytes in vitro.
We present the systematic study of the elastic shear G and bulk B moduli in amorphous and crystalline metastable ternary solid solutions (GaSb)
1−x
Ge
2x
. It is found that the moduli of crystalline ...phases initially decrease with Ge concentration, falling down to minimum values at 20-30% Ge. The minimal values of elastic moduli for amorphous samples are observed at 50-60% Ge. Elastic softness of crystalline solid solutions is assumed to be related to the increase of chemical disorder and, consequently, of static (non-thermal) geometrical disorder in positions of atoms. An additional topological disorder in amorphous solid solutions leads to additional elastic softening.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
