Characteristics of the water-soluble polysaccharides of the leaves ofSilphium perfoliatum

The characteristics of the water-soluble complex of the leaves ofSilphium perfoliatum are given. The presence in them of acidic components of the type of pectic substances containing considerable amounts of compounds of protein nature has been shown. It has proved to be possible to separate the latter from the carbohydrate component by fractionation on DEAE-cellulose.     

On the Point Spectrum of Self-Adjoint Operators That Appears under Singular Perturbations of Finite Rank

We discuss purely singular finite-rank perturbations of a self-adjoint operator A in a Hilbert space . The perturbed operators are defined by the Krein resolvent formula , Im z 0, where B _z are finite-rank operators such that dom B _z dom A = |0}. For an arbitrary system of orthonormal vectors satisfying the condition span | _i } dom A = |0} and an arbitrary collection of real numbers , we construct an operator that solves the eigenvalue problem . We prove the uniqueness of under the condition that rank B _z = n.     

Textured targets of deuterides TiD2, ZrD2, NbD,and CrD2 in experiments to study the pd and dd reaction mechanisms at astrophysical energies

Various methods for depositing thin layers of deuterides (hydrides) TiD₂ (TiH₂), ZrD₂ (ZrH₂), NbD (NbH), and CrD₂ (CrH₂) on stainless steel, copper, and silicon substrates are described. The method for magnetron sputtering of nanolayers of these deuterides (hydrides) with various textures is considered. A technology for producing titanium, zirconium, niobium, and chromium deuteride (hydride) targets is proposed, which will allow the hypothesis of dd and pd reaction enhancement through the channeling of deuterons (protons) in crystals of these deuterides to be unambiguously tested.     

A glucan from Chara aculeolata

Conclusions The roots ofTh. flavum L. have yielded thalicarpine and a new alkaloid, thalflavine, C₁₂H₁₃NO₄, for which the structure of 1-oxo-5-methoxy-2-methyl-6, 7-methlenedioxytetrahydroisoquinoline is proposed.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 4, pp. 444–446, 1970     

Kinetics of formation and properties of aliphatic polyisocyanurates: Effect of monomer functionality

The kinetics of isothermal cyclotrimerization of bifunctional hexamethylene diisocyanate and trifunctional isocyanurate in the presence of hexabutyldistannyl oxide as a catalyst has been studied with differential scanning calorimetry and dielectric relaxation spectroscopy. It has been demonstrated that a rise in the glass transition temperature in the course of cure of the trifunctional monomer is satisfactorily described by the equilibrium first-order kinetics. The evolution of dielectric parameters is similar for both samples but is characterized by a shift along the time scale because of different specific concentrations of isocyanate groups in the parent monomers. Given the same catalyst concentration, the trimerization of hexamethylene diisocyanate proceeds at a higher rate than that of isocyanurate. For maximally cured systems, this effect manifests itself as a small increase in the glass transition temperature and the shear modulus in the rubbery state and a change in the temperature interval of α relaxation.     

Fractionation of the polysaccharides ofChara aculeolata

Summary The carbohydrate complex of the Chara algaChara aculeolata Kütz is peculiar and includes polysaccharides of the types of starch, hemicelluloses, and cellulose and also acid polymers of two types, one of which is esterified with sulfuric acid residues while the other contains D-galacturonic acid as the main component.M. V. Lomonosov Odessa Technological Institute of the Food Industry. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 698–702, November–December, 1976.     

Synthesis of aluminum oxide nanoparticles in an aqueous ammonium-formaldehyde solution

A method of synthesis of the organic-inorganic nanocomposite consisting of a paraformaldehyde matrix and aluminum oxide nanoparticles is developed. Spontaneous dispersion of the composite in water at various component ratios makes it possible to prepare a sol or gel of hydrated aluminum oxide. No changes in the oxide particle dimensions are observed during storage of the composite.     

Intercomparison of radiation measurements on STS-63

A joint NASA Russia study of the radiation environment inside the Space Shuttle was performed on STS-63. This was the second flight under the Shuttle-Mir Science Program (Phase 1). The Shuttle was launched on 2 February 1995, in a 51.65° inclination orbit and landed at Kennedy Space Center on 11 February 1995, for a total flight duration of 8.27 days. The Shuttle carried a complement of both passive and active detectors distributed throughout the Shuttle volume. The crew exposure varied from 1962 to 2790 μGy with an average of 2265.8 μGy or 273.98 μGy/day. Crew exposures varied by a factor of 1.4, which is higher than usual for STS mission. The flight altitude varied from 314 to 395 km and provided a unique opportunity to obtain dose variation with altitude. Measurements of the average east-west dose variation were made using two active solid state detectors. The dose rate in the Spacehab locker, measured using a tissue equivalent proportional counter (TEPC), was 413.3 μGy/day, consistent with measurements made using thermoluminescent detectors (TLDs) in the same locker. The average quality factor was 2.33, and although it was higher than model calculations, it was consistent with values derived from high temperature peaks in TLDs. The dose rate due to galactic cosmic radiation was 110.6 μGy/day and agreed with model calculations. The dose rate from trapped particles was 302.7 μGy/day, nearly a factor of 2 lower than the prediction of the AP8 model. The neutrons in the intermediate energy range of 1–20 MeV contributed 13 μGy/day and 156 μSv/day, respectively. Analysis of data from the charged particle spectrometer has not yet been completed.     

A study of the radiation environment on board the Space Shuttle flight STS-57

A joint NASA-Russian study of the radiation environment inside a SPACEHAB 2 locker on Space Shuttle flight STS-57 was conducted. The Shuttle flew in a nearly circular orbit of 28.5 degrees inclination and 462 km altitude. The locker carried a charged particle spectrometer, a tissue equivalent proportional counter (TEPC), and two area passive detectors consisting of combined NASA plastic nuclear track detectors (PNTDs) and thermoluminescent detectors (TLDs), and Russian nuclear emulsions, PNTDs and TLDs. All the detector systems were shielded by the same Shuttle mass distribution. This makes possible a direct comparison of the various dose measurement techniques. In addition, measurements of the neutron energy spectrum were made using the proton recoil technique. The results show good agreement between the integral LET spectrum of the combined galactic and trapped particles using the tissue equivalent proportional counter and track detectors between about 15 keV/micrometers and 200 keV/micrometers. The LET spectrum determined from nuclear emulsions was systematically lower by about 50%, possibly due to emulsion fading. The results show that the TEPC measured an absorbed dose 20% higher than the TLDs, due primarily to an increased TEPC response to neutrons and a low sensitivity of TLDs to high LET particles under normal processing techniques. There is a significant flux of high energy neutrons that is currently not taken into consideration in dose equivalent calculations. The results of the analysis of the spectrometer data will be reported separately.