An Analysis of the Chemical Composition of the Atmosphere of Venus on an AMS of the Venera-12 Using a Gas Chromatograph

Eight analyses of the atmosphere of Venus were made beginning at an altitude of 42 km right down to the surface of the planet. The following were detected in the atmosphere of Venus: nitrogen in concentrations of 2.5 plus or minus 0.5 volumetric %, argon ir concentrations (4 plus or minus 2) x 10 to the minus 3 power volumetric %, CO--(2.8 plus or minus 1.4) x 10 to the minus 3 power volumetric % and SO2 in concentrations (1.3 plus or minus 0.6) x 10 to the minus 2 power volumetric %. The upper limits were estimated for the content of oxygen and water equal to 2 x 10 to the minus 3 power and 10 to the minus 2 power volumetric %, respectively

Anisotropy in the dielectric function of Bi2_2Te3_3 from first principles: From the UV-visible to the infrared range

The dielectric properties of Bi$_2$Te$_3$, a layered compound crystallizing in a rhombohedral structure, are investigated by means of first-principles calculations at the random phase approximation level. A special attention is devoted to the anisotropy in the dielectric function and to the local field effects that strongly renormalize the optical properties in the UV-visible range when the electric field is polarized along the stacking axis. Furthermore, both the Born effective charges for each atom and the zone center phonon frequencies and eigenvectors needed to describe the dielectric response in the infrared range are computed. Our theoretical near-normal incidence reflectivity spectras in both the UV-visible and infrared range are in fairly good agreement with the experimental spectras, provided that the free carriers Drude contribution arising from defects is included in the infrared response. The anisotropic plasmon frequencies entering the Drude model are computed within the rigid band approximation, suggesting that a measurement of the reflectivity in the infrared range for both polarizations might allow to infer not only the type of doping but also the level of doping.Comment: 29 pages, 10 figure

Хімічні компоненти ефірних олій із надземних частин рослин Pycnanthemum virginianum і P. californicum (Lamiaceae)

Aim. The research is aimed at determining the qualitative and quantitative content of essential oils in the aerial part of two species of the genus Pycnanthemum Michx. (Lamiaceae) – P. virginianum (L.) T. Durand & B.D. Jacks. ex B.L. Rob & Fernald and P. californicum Norr. exDurand. The plants were introduced in the M. M. Gryshko National Botanical Garden of National Academy of Sciences of Ukraine (Forest-Steppe zone). These are representatives of the flora of North America, and they are little known in Ukraine. Plants have useful medicinal and nutritional properties, but the biochemical composition of their essential oils has not been sufficiently studied in the world.Materials and methods. In the experiment, the aerial herbal part of plants collected during the flowering phase was used. The quantitative content of the essential oil was determined by the hydrodistillation method, and its qualitative characteristics were found by the GC-MS analysis. The chromatographic profile was obtained on an Agilent Technologies 7890. The component composition of the essential oil was determined on a gas chromatograph with a HP 6890 mass spectrometric detector with a mass spectrometric detector 5973. We used a mass spectrometric detector 1.6 – 800 a.o.m., EI ionization, SIM & Scan mode, “Hewlett Packard”, USA. Identification of essential oil components was performed using the NIST mass spectrum library in combination with AMDIS content-time identification programs.Results and discussion. P. virginianum was found to produce 1.96 ± 0.17 % of essential oil, in which 12 compounds out of 13 were identified; P. californicum had 2.66 ± 0.13 % of essential oil, 13 compounds out of 15 were identified. The essential oil samples obtained have pulegone as the dominant component: P. virginianum – 44.65 %, P. californicum – 86.07 %. In addition to it, they also contain thymol, myrcene, 1.8-cineole, menthone, limonene and other compounds.Conclusions. For the first time, the qualitative and quantitative composition of the essential oils of plants of P. virginianum and P. californicum species introduced in Ukraine has been determined. The results obtained indicate that when introduced plants have a high biosynthesizing ability to produce essential oil. Pulegone has been found to be the dominant component; therefore, the essential oil can be classified as a pulegone-type essential oil. We believe that the raw material of P. virginianum and P. californicum are potentially suitable for use in perfumery, cosmetics, aromatherapy, personal care products, dentistry, and in the pharmaceutical and food industries.Мета. Визначити якісний склад та кількісний вміст ефірних олій у надземній частині двох видів роду Pycnanthemum Michx. (Lamiaceae) – P. virginianum (L.) T. Durand & B.D. Jacks. ex B.L. Rob & Fernald та P. californicum Norr. ex Durand. Рослини інтродуковано в Національному ботанічному саду імені М. М. Гришка НАН України (лісостепова зона). Це представники флори Північної Америки, а в Україні вони маловідомі. Рослини мають корисні лікувальні та харчові властивості, але біохімічний склад їх ефірних олій у світі вивчено недостатньо.Матеріали та методи. В експерименті використано надземну трав’яну частину рослин, зібрану у фазу квітування. Кількісний вміст ефірної олії визначали методом гідродистиляції, а її якісні характеристики – методом ГХ-МС. Хроматографічний профіль отримували на хроматографі Agilent Technologies 7890. Компонентний склад ефірної олії визначали на газовому хроматографі HP 6890 з мас-спектрометричним детектором 5973. Мас-спектрометричний детектор 1,6 – 800 а.о.м., EI іонізація, SIM & Scan mode, «Hewlett Packard», США. Ідентифікацію компонентів ефірної олії виконували за допомогою бібліотеки мас-спектрів NIST у поєднанні з програмами ідентифікації вмісту AMDIS.Результати та обговорення. Виявлено, що P. virginianum продукує 1,96 ± 0.17 % ефірної олії, у якій ідентифіковано 12 сполук із 13 виявлених; P. californicum – 2,66 ± 0,13 %, ідентифіковано 13 сполук із 15. Отримані зразки ефірної олії за домінантний компонент мають пулегон: P. virginianum – 44,65 %, P. californicum – 86,07 %. Окрім нього, зразки також містять тимол, мірцен, 1,8-цинеол, ментон, лімонен та інші сполуки.Висновки. Уперше визначено якісний та кількісний склад ефірних олій рослин видів P. virginianum та P. californicum, інтродукованих в умови України. Отримані результати свідчать, що за інтродукції рослини мають високу біосинтезувальну здатність продукувати ефірну олію. Виявлено, що домінантним компонентом є пулегон, тому ефірну олію можна кваліфікувати як ефірну олію пулегонного типу. Вважаємо, що сировина P. virginianum та P. californicum потенційно придатна для використання в парфумерії, косметиці, ароматерапії, засобах особистої гігієни, стоматології, у фармацевтичній та харчовій промисловості

Compton Scattering from the Deuteron and Extracted Neutron Polarizabilities

Differential cross sections for Compton scattering from the deuteron were measured at MAX-lab for incident photon energies of 55 MeV and 66 MeV at nominal laboratory angles of $45^\circ$, $125^\circ$, and $135^\circ$. Tagged photons were scattered from liquid deuterium and detected in three NaI spectrometers. By comparing the data with theoretical calculations in the framework of a one-boson-exchange potential model, the sum and difference of the isospin-averaged nucleon polarizabilities, $\alpha_N + \beta_N = 17.4 \pm 3.7$ and $\alpha_N - \beta_N = 6.4 \pm 2.4$ (in units of $10^{-4}$ fm$^3$), have been determined. By combining the latter with the global-averaged value for $\alpha_p - \beta_p$ and using the predictions of the Baldin sum rule for the sum of the nucleon polarizabilities, we have obtained values for the neutron electric and magnetic polarizabilities of $\alpha_n= 8.8 \pm 2.4$(total) $\pm 3.0$(model) and $\beta_n = 6.5 \mp 2.4$(total) $\mp 3.0$(model), respectively.Comment: 4 pages, 2 figures, revtex. The text is substantially revised. The cross sections are slightly different due to improvements in the analysi

Observation of the strangulated internal hernia of Petersen

Observation of the strangulated internal hernia of Peterse

Quasi-free π0\pi^0 Photoproduction from the Bound Nucleon

Differential cross-sections for quasi-free $\pi^0$ photoproduction from the proton and neutron bound in the deuteron have been measured for $E_\gamma= 200 - 400$ MeV at $\theta^{\rm lab}_\gamma = 136.2^\circ$ usind the Glasgow photon tagger at MAMI, the Mainz 48 cm $\varnothing$ $\times$ 64 cm NaI(Tl) photon detector and the G\"ottingen SENECA recoil detector. For the proton measurements made with both liquid deuterium and liquid hydrogen targets allow direct comparison of "free" $\pi^0$ photoproduction cross-sections as extracted from the bound proton data with experimental free cross sections which are found to be in reasonable agreement below 320 MeV. At higher energies the "free" cross sections extracted from quasifree data are significantly smaller than the experimental free cross sections and theoretical predictions based on multipole analysis. For the first time, "free" neutron cross sections have been extracted in the $\Delta$-region. They are also in agreement with the predictions from multipole analysis up to 320 MeV and significantly smaller at higher photon energies

Modeling of contact interaction of a heated plane rigid elliptical punch with a transversally isotropic elastic half-space

On the base of a rigorous mathematical model, the problem of the contact interaction of a heated flat punch of an elliptical section with a transversely isotropic elastic half-space is investigated. It is assumed that the half-space surface is the isotropy plane of a transversely isotropic material, and also that there is a smooth (without friction) contact. Expressions of contact stresses and displacements of a heated flat elliptical punch are found explicitly. In the form of a simple inequality, a condition for separating the elastic material from the surface of a flat elliptical punch is obtained. Numerical calculations are carried out. Contact interaction of a heated flat punch is studied taking into account the separation of material from the punch

Neutron polarizabilities investigated by quasi-free Compton scattering from the deuteron

Measuring Compton scattered photons and recoil neutrons in coincidence, quasi-free Compton scattering by the neutron has been investigated at MAMI (Mainz) at $theta^{lab}_\gamma=136^o$ in an energy range from 200 to 400 MeV. From the data a polarizability difference of $\alpha_n - \beta_n = 9.8 \pm 3.6(stat)^{+2.1}_{-1.1}(syst)\pm 2.2(model)$ in units of $10^{-4}fm^3$ has been determined. In combination with the polarizability sum $\alpha_n+\beta_n= 15.2\pm 0.5$ deduced from photo absorption data, the neutron electric and magnetic polarizabilities, $\alpha_n=12.5\pm 1.8(stat)^{+1.1}_{-0.6}(syst)\pm 1.1(model)$ and $\beta_n = 2.7\mp 1.8(stat)^{+0.6}_{-1.1}(syst)\mp 1.1(model)$, are obtained