Growth of graphene on 6H-SiC by molecular dynamics simulation

Classical molecular-dynamics simulations were carried out to study epitaxial growth of graphene on 6H-SiC(0001) substrate. It was found that there exists a threshold annealing temperature above which we observe formation of graphitic structure on the substrate. To check the sensitivity of the simulation results, we tested two empirical potentials and evaluated their reliability by the calculated characteristics of graphene, its carbon-carbon bond-length, pair correlation function, and binding energy.Comment: 7 pages, 5 figure

Проект цеха получения порошкообразного тантала с помощью магнийтермического восстановления пентаоксида тантала, производительностью 40 т/год по танталовому порошку

В данном дипломном проекте была предложена аппаратурно-технологическая схема получения порошкообразного тантала с помощью магнийтермического восстановления пентаоксида тантала, производительностью 40 т/год по танталовому порошку. На основе данных материальных балансов было подобрано основное и вспомогательное оборудование для проведения магнийтермического восстановления. Основным аппаратом выбрана установка стесненного падения для проведения восстановления оксида тантала магнием высотой 2,6 м, диаметр-0,25 м. На основе подобранного технологического оборудования разработан цех магнийтермического восстановления. Был произведен расчет заработной платы работников. Рассчитана себестоимость конечного полупродукта. Рассмотрены основные пункты социальной ответственности.In the diploma project was proposed an instrumentation-technological scheme for the processing of obtaining powdered tantalum by means of magnesium-thermal reduction of tantalum pentoxide, with a capacity of 40 tons per year for tantalum powder. Based on the data of material balances, the main and auxiliary equipment for magnesium-thermal recovery was selected. Was chosen the main device - cramped fall installation to carry out the reduction of tantalum oxide with magnesium 2.6 m in height,diameter-0.25 m. On the basis of the selected auxiliary equipment, was made a plan of the working area .The calculation of the personnel number of the personnel, the basic wage fund, the cost of the final semi-product has been made. Was introduced with the main points of social responsibility

Lectin prospecting in Colombian Labiatae. A systematic-ecological approach. - II

This is the second study of lectin and mucilage detection in Labiatae nutlets from Colombia. It was carried out on 31 taxa belonging to 7 genera in which no previous studies have been carried out in this field. A differential response was observed in the group of genera and species studied in terms of mucilage presence as well as lectin activity which consistently increased following extract treatment with Pectinex. Lectin activity was detected in 28 species, being important (greater than 60% activity) in at least 75% of them. Genera such as Hyptis, Scutellaria, Aegiphila and Lepechinia, whilst not presenting mucilage, did present lectin activity, having high activity in most cases. By contrast, Salvia (in all sections studied) presented mucilage and important lectin activity.Este es el segundo estudio sobre la presencia de mucílagos y lectinas en núculas de Labiadas colombianas. Se llevó a cabo en 31 taxones, pertenecientes a siete géneros, sobre los cuales no se disponía de información en este campo. Se observó una respuesta diferencial en los géneros y especies en lo relativo a la presencia de mucílago y a la actividad de lectina que se incrementó de manera consistente después de tratar los extractos con Pectinex. Se detectó actividad de lectina en 28 especies, siendo muy importante (mayor del 60%) en al menos 75% de ellas. Aunque los géneros Hyptis, Scutellaria, Aegiphila y Lepechinia no presentaron mucílago, su actividad de la lectina fue alta. Por el contrario Salvia (en todas las secciones estudiadas) presentó mucílago y una actividad importante de lectina.Peer reviewe

Highly variable AFLP and S-SAP markers for the identification of ‘Malbec’ and ‘Syrah’ clones

The retrotransposon-based sequence-specific amplification polymorphism (S-SAP) and the amplified fragment length polymorphism (AFLP) marker systems were used to assess the clonal variation of 14 ‘Syrah’ and 22 ‘Malbec’ (Vitis vinifera L.) clones. The utility of S-SAP markers was compared to that of AFLP markers. On the basis of our results, S-SAP is more informative marker system and showed higher average number of polymorphic bands per cultivar group than AFLP. Relationships among clones were analyzed by cluster analysis using unweighted pair-groups using arithmetic averages and in both cases revealed well defined groups of clones, in which ‘Malbec’ clones were separated from ‘Syrah’ clones. High variability of some clones could also be seen within these clusters. The different levels of polymorphism for ‘Malbec’ and ‘Syrah’ obtained in this study suggest that ‘Malbec’ exhibits a higher mutation frequency than ‘Syrah’. Our results indicate that higher proportion of polymorphic bands in S-SAP makes it a less labour-intensive and more efficient approach for developing markers for clonal identification.

Experimental researches of mechanoelectrical transformations in tashtagolsky iron-ore field rock

Physical modeling in lab is approach of definition of main mechanical transformations behaviours inrock massive for choice of electromagnetical signals optimum characteristics and parameters ofelectomagnetical emission for developed approach of crush burst estimate. It is support connection betweenmechanoelectrical transformations characteristics and stress strain state of researched object. Physical modelingof mechanoelectrical transformations in the lab was made under a press by axial quasistatic compression of rockspecimen up to destruction. During stressing applied injections of specimens using determined acoustic signals. For researches used model and real specimens of Tashtagolsky iron-ore field rock, such as ore and matrix rock

Интерактивная обработка изображений, получаемых посредством лазерного монитора в режиме реального времени

В ходе исследования необходимо было создать устройство позиционирования объекта в системе лазерного монитора. В процессе исследования проводилось исследование алгоритмов определения резкости изображения. На основе выбранного метода был разработан алгоритм автоматической фокусировки изображения. Также был разработан алгоритм системы слежения за объектом на основе алгоритма нормированной кросскорреляции. В результате исследования удалось снизить искажения, вносимые оптической системой лазерного монитора и активной оптической средой, и организовать систему автоматической фокусировки изображения и систему слежения, позволяющую отслеживать перемещение объекта наблюдения с точностью до 1 пикселя.In the study, it was necessary to create a device object positioning system for the laser monitor. The study surveyed algorithms determine the sharpness of the image. Based on the selected method algorithm for automatic focus of the image was developed. There was also designeded a tracking system for the object of the algorithm based on normalized cross-correlation method. The study was able to reduce the distortions introduced by the optical system of the laser and monitor the active optical medium, and to organize a system of auto focus and image tracking system to track the movement of the object of observation up to 1 pixel

Cystic lymph node metastases of squamous cell carcinoma of Waldeyer's ring origin

We analysed in a retrospective study the frequency of cystic lymph node (LN) metastases in neck dissection specimens of 123 patients with primary squamous cell carcinoma (SCC) arising in the palatine tonsils (62 M/14 F), the base of the tongue (38 M/5 F) and the nasopharynx (2 M/2 F). Eighty-two per cent of patients had metastases (64 tonsillar SCC, 33 base of tongue SCC and all four nasopharynx SCC) in 368 LN of a total 2298 sampled LN. Thirty-nine per cent of patients had exclusively solid metastases and 37% of patients had exclusively cystic metastases. A total of 62 patients had some signs of cyst formation in one or more metastatically affected LN (27 with only histological evidence of cyst formation with luminal diameters < 5 mm, 35 with clinically detectable cyst with luminal diameter > 5 mm). Cystic metastases were more common in patients with SCC of the base of the tongue (P = 0.005), while solitary clinically evident cystic metastasis with lumina > 5 mm were found exclusively in tonsillar carcinoma (P = 0.024). In comparison with solid metastases, cyst formation was associated with N-categories (N2b and N3, P = 0.005) in SCC of the base of the tongue origin. No such association was observed for tonsillar SCC (P = 0.65). The primary mechanism of cyst formation was cystic degeneration. © 1999 Cancer Research Campaig