The lower-boundary asymptotics of continuous spectrum for quantum layers laterally coupled by a periodic system of small windows

2001 ◽  
Vol 27 (10) ◽  
pp. 855-856 ◽  
Author(s):  
I. Yu. Popov
Keyword(s):  
Continuous Spectrum ◽  
Periodic System ◽  
Lower Boundary

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

Study of charge transfer in FeTi

1983 ◽  
Vol 41 ◽  
pp. 296-297
Author(s):  
J. Taft∅
Keyword(s):  
Charge Transfer ◽  
Charge Distribution ◽  
Electron Scattering ◽  
Periodic System ◽  
Electron Distribution ◽  
Scattering Amplitude ◽  
Transition Elements ◽  
Hartree Fock ◽  
Cscl Structure ◽  
The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

Element 103 of the periodic system

1968 ◽  
Vol 14 (3) ◽  
pp. 331-339 ◽  
Author(s):  
E. D. Donets ◽  
V. A. Druin ◽  
V. L. Mikheev
Keyword(s):  
Periodic System

The stability of heavy nuclei and the limit of the periodic system of elements

1970 ◽  
Vol 100 (1) ◽  
pp. 45-92 ◽  
Author(s):  
G.N. Flerov ◽  
V.A. Druin ◽  
A.A. Pleve
Keyword(s):  
Periodic System ◽  
Heavy Nuclei ◽  
The Stability

Morphometric characteristics of competent proximal valves of the great saphenous vein and superficial femoral vein in vivo according to ultrasound angioscanning data

2019 ◽  
Vol 18 (3) ◽  
pp. 16-22
Author(s):  
E. K. Gavrilov ◽  
H. L. Bolotokov ◽  
E. A. Babinets
Keyword(s):  
Saphenous Vein ◽  
Great Saphenous Vein ◽  
Femoral Vein ◽  
Lower Boundary ◽  
Average Diameter ◽  
Lower Limbs ◽  
Functional Test ◽  
Natural Form ◽  
Superficial Femoral Vein ◽  
Venous Diameter

Introduction. It seems relevant to study the ultrasound anatomy and physiology of the proximal valve segments of the superficial femoral vein (SFV) and the great saphenous vein (GSV) to develop effective reconstructive surgical interventions on venous valves in chronic vein diseases.The aim of the survey was to study the ultrasound anatomy of the venous wall, the size and shape of the proximal SFV and GSV valves are normal at rest and during the functional test Valsalva.Material and methods. Proximal valve SFV studies were performed in 144 lower limbs in 115 people (mean age 51.1 ± 14.4 years, 60 women and 55 men), proximal GSV valves studies - in 82 lower limbs in 67 persons (average age 45, 1 ± 13.3 years, 33 women, 34 men). A longitudinal and transverse ultrasound scanning of the femoral vein bifurcation and safenofemoral junction areas were performed, the structures of the proximal SFV and GSV valves were visualized, the valve shape was measured and the diameter of the veins was measured at the level valves at the base of the valves (inlet diameter), at the point of maximum ectasia (diameter of ectasia), at the upper border of the valve (diameter of the outlet), as well as measuring the length of the valve a (length to ectasia, the total length of the valve). The degree of ectasia over the valve was judged by calculating the relative venous diameter change (RVDC).Results. the average diameter of the SFV at the level of the lower boundary of its first valve was 10.01 ± 1.44 mm. The average diameter of the SFV at the level of the maximum ectasia of its first valve was 13,1±2 mm. The average value of the index of RVDC for SFV was 31%±10,4%. An increase in the diameter of the vein in the zone of supravalvular ectasia up to 20% corresponded to the spindle-shaped valve, more than 20% - to the clavate form, which was noted in the majority of the examined. The change in the relative venous diameter of the SFV on the Valsalva test was 38,2%±12,4%. The average diameter of the GSV at the base of the first valves was 6,07±1,25 mm. The average diameter of the GSV at the level of the maximum ectasia of the osteal valve was 9,44±1,69 mm. The average RVDC for GSV was 58%±24%.Conclusion. the natural form of proximal SFV and GSV valves is clavate with presence of the significant supravalvular ectasia, which was noted in the majority of the subjects alone and in all during the performance of the Valsalva functional test.

Assessment of nutritional status of students of medical institute according to the blood biochemical parameters

2020 ◽  
pp. 55-63
Author(s):  
Rofail Rakhmanov ◽  
Elena Bogomolova ◽  
Mariya Shaposhnikova ◽  
Mariya Sapozhnikova
Keyword(s):  
Nutritional Status ◽  
Lower Boundary ◽  
Density Lipoprotein ◽  
Blood Parameters ◽  
Medical Institute ◽  
Specific Situation ◽  
Mathematical Methods ◽  
Normal Range ◽  
Mean Values ◽  
The Mean

The biochemical blood parameters characterizing the students ’nutritional status were evaluated: protein, lipid, carbohydrate metabolism, a number of minerals. The mean values, errors of the mean, median (Me), boundary (Q) and the range of 25–75 percentiles were determined. In 9.1 % of students and 28.6 % of students, the total protein was increased. Creatinine in men was in the upper normal range, in women — at the upper limit of normal, of which 46.2 % was higher than normal. The interval Q25–75 of uric acid in students is determined in the lower normal zone. In 40.0 % of men, decreased high-density lipoprotein cholesterol (Q25–75 corresponded to 1.15–1.79), in women — below normal, Q25–75 5 was 1.3–1.5, decreased in 73.3 %. Me and Q25–75 iron were in the lower normal range; 14.1 % of men and 13.2 % of women are below normal. Me sodium and potassium at the level of the lower boundary of the norm, Q25–75 in the lower zone of the norm: in 16.0 % and 15.4 % of students the levels are reduced. Calcium is slightly above the lower limit of the norm, Q25–75–2.1–2.24, indicating an insufficient intake in the whole group; 25.0 % are below normal. The border of the 25th percentile of magnesium is at the level of the lower border of the norm, in 19.2 % it is reduced. 7.2 % lack of chlorine. Phosphorus is normal, but Q25–75 is in the upper zone; 17.9 % increased. Biochemical markers can identify individuals with metabolic disorders of nutrients. Statistical indicators — the median, the boundaries of 25–75 quartiles and their scope characterize the metabolism of macronutrients and minerals in the group and subgroups of students. Laboratory and mathematical methods can provide a basis for identifying the specific causes of these changes. For this, you can use the questionnaire method of studying the nutrition of students, possibly using the developed questionnaires for a specific situation.

17O, 13C, and 29Si NMR spectra of some acyloxy- and diacetoxysilanes and acetoxygermanes

1986 ◽  
Vol 51 (11) ◽  
pp. 2582-2589 ◽  
Author(s):  
Antonín Lyčka ◽  
Jaroslav Holeček ◽  
Karel Handlíř ◽  
Josef Pola ◽  
Václav Chvalovský
Keyword(s):  
Periodic System ◽  
Time Scale ◽  
Nmr Spectra ◽  
Group Element ◽  
29Si Nmr ◽  
Carboxyl Group ◽  
29Si Nmr Spectra ◽  
Oxygen Atoms

The 17O, 13C, and 29Si NMR spectra of (CH3)3SiOC(O)R, CH3(XCH2)Si(OC(O)CH3)2, and R3GeOC(O)CH3 compounds are reported. In the 17O NMR spectra at 350 K the only signal is observed with the two latter series, but two well-resolved signals are displayed with the (CH3)3SiOC(O)R compounds. The equivalence of both oxygen atoms in carboxyl group on the NMR time scale is discussed from the viewpoint of a possible coordination of the oxygen atoms to the IVB group element of the periodic system.

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