Učinak toplinske obradbe na mehanička svojstva i karakter loma traka molibdenskih legura

The annealing temperature within the range of 1223 - 2273 K has been studied for its effect on the grain size, mechanical properties, cold brittleness temperature, and nature of failure of sheets molybdenum alloys TsM-6 and TsM-10. The method of Auger-electron microscopy has been used to study the change of carbon and oxygen content on grain boundaries of the alloy TsM-10 and the change of mechanical properties associated with it as dependent on the annealing temperature.Istraživan je utjecaj temperaturnog žarenja u dijapazonu 1223 - 2273 K na veličinu zrna, mehanička svojstva, temperaturu hladnog loma i karakter razaranja traka molibdenskih legura TsM-6 i TsM-10. Auger-metodom elektronske mikroskopije istraživana je promjena sadržaja ugljika i kisika na granici zrna legure Tsm-10 i povezano s tim promjene mehaničkih karakteristika u zavisnosti od temperature žarenja

Взаємодія 4,5-диформіл-2,3,6,7,8,10-гексагідроакридин-8а(1Н)-карбонітрилу з N-нуклеофілами

Schiff bases are of practical interest as initial materials both for the combinatorial synthesis for libraries of compounds, and for preparation of complexes with metals; thus, currently the intensity of research in this direction is increasing. The possibilities of practical use of complex compounds with organic ligands are quite broad varying from effective catalysts of various chemical processes to molecular sensors. While studying formylation of 5,6,7,8-tetrahydro-1H-spiro[cyclohexane-1,2-quinazolin]-4’(3’H)-one a new domino reaction, which makes it possible to obtain tricyclic acridine systems, has been carried out. In spite of the reduced electrophilicity of the aldehyde groups in 4,5-diformyl-2,3,6,7,8,10-hexahydroacridine-8а(1H)-carbonitrile the latter is shown to react with various amines in benzene with azeotropic removal of water using p-TsOH as a catalyst, and with hydroxylamine hydrochloride in i-PrOH. New Schiff bases and oxime obtained are of potential interest as ligands for formation of chelate complexes. The reaction of dialdehyde with N2H4×H2O instead of the expected hydrazone resulted in obtaining a macrocyclic compound – a derivative of hexaazacyclooctadecine. The structure of the compounds obtained corresponds to the data of 1H NMR-spectroscopy, mass spectrometry and elemental analysis. The preliminary studies have shown that azomethines – 4,5-phenyl(cyclohexcyl)iminomethyl-2,3,6,7,8,10-hexahydroacridine8а(1H)-carbonitrile create complexes with copper and nickel ions.Основания Шиффа представляют практический интерес в качестве исходных как для комбинаторного синтеза библиотек веществ, так и для создания комплексов с металлами, и в последнее время интенсивность исследований в данном направлении только увеличивается. Возможности практического использования комплексных соединений с органическими лигандами весьма широки: от эффективных катализаторов различных химических процессов до молекулярных сенсоров. В ходе изучения формилирования 5’,6’,7’,8’-тетрагидро-1’Н-спиро[циклогексан-1,2’-хиназолин]-4’(3’Н)-она нами была найдена новая домино-реакция, которая позволяет выйти на трициклические гидрированные акридиновые системы. Показано, что несмотря на сниженную электрофильность альдегидных групп в 4,5-диформил2,3,6,7,8,10-гексагидроакридин-8а(1Н)-карбонитриле, он реагирует с различными аминами в бензоле с азеотропной отгонкой воды с применением в качестве катализатора p-TsOH, а также с солянокислым гидроксиламином в i-PrOH. Полученные основания Шиффа и оксим представляют потенциальный интерес в качестве лигандов для образования хелатных комплексов. В результате реакции диальдегида с N2H4×H2O вместо ожидаемого гидразона получено макроциклическое соединение – производное гексаазациклооктадецина. Строение всех полученных соединений согласуется с данными ЯМР 1Н-спектроскопии, масс-спектрометрии и элементного анализа. Предварительные исследования показали, что азометины − 4,5-фенил(циклогексил)иминометил-2,3,6,7,8,10-гексагидроакридин-8а(1Н)карбонитрила образуют комплексные соединения с ионами никеля и меди. Основи Шиффа становлять практичний інтерес в якості вихідних як для комбінаторного синтезу бібліотек речовин, так і для створення комплексів з металами, і останнім часом інтенсивність досліджень у даному напрямку тільки збільшується. Можливості практичного використання комплексів з органічними лігандами досить широкі: від ефективних каталізаторів хімічних процесів до молекулярних сенсорів. У ході вивчення формілювання 5’,6’,7’,8’-тетрагідро-1’Н-спіро[циклогексан-1,2’-хіназолін]-4’(3’Н)-ону нами була відкрита нова доміно-реакція, яка дозволяє вийти на трициклічні гідровані акридинові системи. Показано, що незважаючи на знижену електрофільність альдегідних груп у 4,5-диформіл-2,3,6,7,8,10-гексагідроакридину-8а(1Н)-карбонітрилі, він реагує з різними амінами у бензолі з азеотропною відгонкою води з використанням в якості каталізатора p-TsOH, а також з солянокислим гідроксиламіном у i-PrOH. Отримані основи Шиффа та оксим становлять потенційний інтерес у якості лігандів для утворення хелатних комплексів. У результаті реакції діальдегіду з N2H4×H2O замість очікуваного гідразону отримано макроциклічну сполуку – похідну гексаазациклооктадецину. Будова всіх отриманих сполук підтверджена даними ЯМР 1Н-спектроскопії, мас-спектрометрії і елементного аналізу. Попередні дослідження продемонстрували, що азометини – 4,5-феніл(циклогексил)імінометил-2, 3,6,7,8,10-гексагідроакридин-8а(1Н)-карбонітрилу утворюють комплексні сполуки з іонами нікелю та міді

Electrospun amplified fiber optics

A lot of research is focused on all-optical signal processing, aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for an efficient signal transmission. However, the complex fabrication methods, involving high-temperature processes performed in highly pure environment, slow down the fabrication and make amplified components expensive with respect to an ideal, high-throughput and room temperature production. Here, we report on near infrared polymer fiber amplifiers, working over a band of about 20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and show amplified spontaneous emission with good gain coefficients as well as low optical losses (a few cm^-1). The amplification process is favoured by the high fiber quality and low self-absorption. The found performance metrics promise to be suitable for short-distance operation, and the large variety of commercially-available doping dyes might allow for effective multi-wavelength operation by electrospun amplified fiber optics.Comment: 27 pages, 8 figure

Serum and follicular fluid organochlorine concentrations among women undergoing assisted reproduction technologies

<p>Abstract</p> <p>Background</p> <p>Exposure to persistent organic pollutants, including polychlorinated biphenyls (PCBs) and organochlorine pesticides, is widespread among the general population. There is evidence of adverse effects on reproduction and early pregnancy in relation to organochlorine exposure but human studies remain limited. The increased use of assisted reproductive technologies (ART) presents unique opportunities for the assessment of environmental influences on early pregnancy outcomes not otherwise observable in humans, but studies need to be designed to maximize the efficiency of the exposure data collected while minimizing exposure measurement error.</p> <p>Methods</p> <p>The present study was conducted to assess the correlation between concentrations of organochlorines in serum and follicular fluid samples collected from a subset of women undergoing ART in a large study that took place between 1994 and 2003, as well as the temporal reliability of serum organochlorine concentrations among women undergoing multiple ART cycles in the study. PCB congeners (118, 138, 153, and 180), 1,1,1-trichloro-2,2-bis(<it>p</it>-chlorophenyl)ethane (p,p'-DDT), the DDT metabolite p,p'-DDE, hexachlorobenzene (HCB), oxychlordane, trans-nonachlor and mirex were measured in 72 follicular fluid samples and 265 serum samples collected from 110 women.</p> <p>Results</p> <p>Organochlorine concentrations in paired serum and follicular fluid samples were correlated, with Pearson and Spearman coefficients ranging from 0.60 to 0.92. Serum organochlorine concentrations were two- to three-fold greater than in follicular fluid, and a significant inverse trend was observed in the distribution of follicular fluid:serum ratios with increasing molecular weight of the compound (p-value for trend < 0.0001). Serum organochlorine concentrations were highly reliable over the course of several months, with intraclass correlation coefficients ranging from 0.86 to 0.98. Finally, there was evidence for a declining trend in organochlorine concentrations between samples collected between years 1994–1998 and those collected in 1999–2003.</p> <p>Conclusion</p> <p>Our results support the use of a single serum sample to adequately represent a more biologically relevant dose (concentrations in follicular fluid), as well as exposure levels over time, in epidemiological studies of ART outcomes in relation to organochlorine exposure.</p

Improving Security at Work with Software that Uses OpenMP

A model of the offender and the list of major types of threats, the conditions for the realization of which are created by using the software that uses OpenMP is considered. A method for verification of software using OpenMP for the presence of vulnerabilities associated with multi-threaded execution is offered. We give basic algorithms and the system architecture that implements the proposed method. The results of testing the method on various programs, including those containing malicious code, as well as assessment of the possibilities of applying the method in different computing environments are given