759 research outputs found
Studies on Bis(imido) molybdenum complexes containing unsaturated hydrocarbon ligands
No full textThis thesis describes the synthesis and characterisation of molybdenum bis(imido) complexes containing unsaturated hydrocarbon ligands. A principal objective of the work was to examine the effect of various imido substituents on the coordination number of the complex and the orientations adopted by olefin and acetylene ligands. Chapter One highlights areas of transition metal chemistry relevant to the thesis, with particular emphasis on the psuedo-isolobal analogy between cyclopentadienyl and imido ligands, A convenient one-pot synthesis of molybdenum bis(imido) complexes of the type Mo(NR)(NR')Cl(_2).DME (R=R'=l-adamantyl, 2-t- BUC(_6)H(_4); R=2,6-i-Pr(_2)C(_6)H(_3), R'=t-Bu) is described in Chapter Two. Mo(N-l- adamantyl)(O)Cl(_2).DME has been synthesised, and its structure determined by single crystal X-ray diffraction.- The preparation of olefin complexes Mo(NR)(NR')(C(_2)H(_4))(PMe(_3))n (R=R'=l-adamantyl, n=l; R=R'=2-t-BuC(_6)H(_4), n=2; R=2,6-i-Pr(_2)C(_6)H(_3), R'=t- Bu, n=l) is outlined in Chapter Three. Structural information derived from NMR data has allowed comparison with metallocene-like olefin adducts. Chapter Four describes the synthesis of complexes containing σ-bound phenyl ligands (Mo(NR)(NR')(σ-C(_6)H(_5))(PMe(_3)) (R=R'=l-adamantyl, 2-t-BuC(_6)H(_4); R=2,6-i-Pr(_2)C(_6)H(_3), R'=t-Bu)) as potential precursors to benzyne complexes. Chapter Five describes the preparation of diphenylacetylene complexes Mo(NR)(NR')(PhC=CPh)(PMe(_3)), structural information derived from NMR data allows comparison with previously known metallocene-like acetylene complexes. Full experimental details for Chapters Two to Five are given in Chapter Six
VIBRATIONAL SPECTRA AND BARRIER TO INTERNAL ROTATION OF AND
No full textAuthor Institution: National Bureau of StandardsRecent interest in derivatives of prompted a vibrational study of and . Raman spectra of the liquid and gas phases were recorded from 100 to 2700 . Infrared spectra of the vapors were recorded from 200 to 2700 . All nine fundamentals were observed and assigned for both molecules. The observation of 7 polarized and 2 depolarized Raman bands confirm the planar configuration. The infrared vapor spectra showed the fundamental and three ``hot” bands of the SH(D) torsional vibration. A comparison of our spectral results with an earlier study is presented. The structure of the infrared torsional band allowed calculation of the barrier toward internal rotation. Barrier values of 11.8 and 12.4 Kcal/mol were calculated for the protonated and deuterated molecules, respectively, utilising the potential. Potential barrier values of 10.2 and 9.9 were obtained with the quartic potential, . The potential barrier calculations, utilizing two different potential functions, afforded an evaluation of the choice of potentials for double minimum systems with high barriers. A barrier of about Kcal/mol is estimated for this species. Thermodynamic functions were also calculated
The naval-based helicopter SH-2G as part of the ship defence system
No full textZadania nowoczesnego lotnictwa pokładowego sił morskich są bardzo zróżnicowane, ponieważ obejmują: misje uderzeniowe na cele nawodne, podwodne i lądowe, osłonę z powietrza zespołów okrętów lub oddziałów ekspedycyjnych (piechoty morskiej) w czasie desantu morskiego, transport sprzętu, zaopatrzenia i ludzi, misje ratownicze. Dla statków powietrznych (SP) stacjonujących na lotniskowcach lub okrętach wsparcia, te właśnie okręty stanowią jedynie środek transportu do podejścia w rejon działania i jako ich baza logistyczna. Po starcie z lotniskowca SP wykonują zadanie na rzecz wojsk własnych w oddaleniu od macierzystego okrętu, na który wracają dopiero po wykonaniu misji lub w sytuacji awaryjnej. Natomiast śmigłowiec operujący z korwety lub fregaty w przeważającej części działa na rzecz własnego okrętu. Jest traktowany jak integralna część systemu uzbrojenia okrętu. Zdaniem autora, jest to najbardziej efektywny, wielozadaniowy system uzbrojenia okrętu. W siłach morskich państw, dowódcy okrętów, którzy od dawna wykorzystują własne śmigłowce pokładowe zrozumieli, że bez nich nie byliby w stanie wykonać stawianych przed nimi zadań. Śmigłowiec jako integralna cześć okrętu nie tylko zwiększa zdolności ofensywne, ale także obronne macierzystego okrętu. Jedną z koncepcji nowego wykorzystania śmigłowca pokładowego, wykonującego zadania z pokładów mniejszych okrętów, był program LAMPS (Light Airborne Multi Purpose System) - Lekki Powietrzny System Wielozadaniowy. Został on opracowany na początku lat 70. XX wieku przez MW USA (US Navy). Koncepcja ta zakładała rozbudowę możliwości bojowych pojedynczego okrętu poprzez zwiększenie możliwości jego śmigłowca pokładowego. Jednym z przedstawicieli śmigłowca zbudowanego według koncepcji LAMPS jest śmigłowiec SH-2G, obecnie eksploatowany przez MW RP, który współdziała z fregatami rakietowymi typu Oliver Hazard Perry. W artykule zostały przedstawione główne założenia koncepcji LAMPS, jej modyfikacje oraz podstawowe zadania realizowane przez śmigłowce SH-2G w ramach współdziałania z macierzystym okrętem.The demands of modern naval aerospace are very widely-spread, as they include strike missions on seaborne, underwater and land-based targets, aerial defense of carrier fleets or expeditionary units of navy infantry during a seaborne attack, transport of equipment, supplies and manpower as well as rescue missions. For aircraft stationed on carriers or support ships, these vessels represent only a means of transport to arrive at the region of activity and as their logistical base. After takeoff from the aircraft carrier, aircraft carry out missions for their own forces removed from their mother ship, to which they return only after completion of the mission or in an emergency. On the other hand, a helicopter operating from a corvette or frigate is used mostly in the service of its own vessel. It is regarded as an integral part of the weapon system of the vessel. In the opinion of the author, it is the most effective, multi-task weapon system of the vessel. In national naval forces, the vessel commanders, who since long ago have used helicopters based on their own vessel, have understood that without them they would lack the ability to carry out the missions handed to them. A helicopter as an integral part of the vessel not only increases offensive capabilities, but also the defensive capabilities of the mother ship. One of the concepts for a new application of the naval-based helicopter, carrying out missions from the decks of smaller vessels, was the LAMPS (Light Airborne Multi Purpose System). It was developed at the beginning of the 1970s by the US Navy. This concept assumed the upgrading of combat capabilities of a single vessel through the increase of the capabilities of its deck-based helicopter. One of the leading examples of helicopters built according to the LAMPS concept is the SH-2G helicopter, currently used by the Polish navy. In the paper, the main assumptions of the LAMPS concept, its modifications as well as the basie missions carried out by the SH-2G helicopter as part of a cooperation with its mother ship are presented
O zahodnojužnoslovanskem nasprotju sln. sah-ni-ti // sh. sah-nu-ti
No full textENGLISH: The paper reexamines the traditional explanation for the "idiosyncratic development'' of the Common Slavic Class II verbs with the aorist and/or infinitive suffix -n-, attested in OCS sъxnti 'dry', P schnąć, R soxnut', SC sahnuti, but in Slovenian as sahniti. The peculiarity that gave rise to this development in Slovenian is generally thought to be simple analogy with the Class IV verbs, e.g., braniti 'defend'. In the course of this reexamination, the author shows how the "idiosyncratic development,'' once restated, fits in with data from other Slavic languages. Rather than proceeding from the assumption that the -ntype was replaced by -ni-, the author demonstrates that it is reasonable to depart from a Common Slavic dialect difference -n// -ny(dialects.
SLOVENE: Prispevek na novo ocenjuje tradicionalno razlago za "svojevrsten razvoj" praslovanskih glagolov II. razreda z aoristno in/ali nedoločniško pripono -n-, ki so izpričani v scsl. kot sъxnti 'sahniti', pol. schnąć, rus. soxnut', sh. sahnuti, vendar v sln. kot sahniti. Običajno se ta posebni razvoj v slovenščini razlaga kot preprosta analogija z glagoli IV. razreda, npr. braniti. V toku te nove ocene avtor kaže, da se "svojevrsten razvoj" — takoj ko je na novo prikazan — ujema s podatki iz drugih slovanskih jezikov. Namesto da bi izhajal iz domneve, da je pripona -niizpodrinila -n-, avtor dokazuje, da je smiselno izhajati iz praslovanske razlike -n// -ny(-
Cytokine Regulation In Pubertal Girls With Opsomenorrhea Across Different Body Mass Index Categories
No full textMenstrual rhythm disturbances during puberty often reflect a combination of neuroendocrine immaturity and early forms of ovulatory dysfunction. In the context of abnormal body weight, inflammatory mechanisms may serve as an additional factor modulating reproductive regulatio
FEATURES OF CYTOKINE PROFILE DYNAMICS IN WOMEN WITH UTERINE FIBROIDS AFTER RADIOFREQUENCY ABLATION IN ORGAN-PRESERVING TREATMENT
No full textUterine fibroids are one of the most common benign tumors in women of reproductive and perimenopausal age and are accompanied by activation of inflammatory, angiogenic, and fibrotic mechanisms. With the development of minimally invasive organ-preserving technologies, there is a growing interest in assessing the molecular effects of radiofrequency ablation (RF) on the microenvironment of the myometrial tissue
FEATURES OF CYTOKINE PROFILE DYNAMICS IN WOMEN WITH UTERINE FIBROIDS AFTER RADIOFREQUENCY ABLATION IN ORGAN-PRESERVING TREATMENT
No full textUterine fibroids are one of the most common benign tumors in women of reproductive and perimenopausal age and are accompanied by activation of inflammatory, angiogenic, and fibrotic mechanisms. With the development of minimally invasive organ-preserving technologies, there is a growing interest in assessing the molecular effects of radiofrequency ablation (RF) on the microenvironment of the myometrial tissue
The Cartesian product of a compactum and a space is a bifunctor in shape
No full textAbstractIn 2003 the author has associated with every cofinite inverse system of compact Hausdorff spaces X with limit X and every simplicial complex K (possibly infinite) with geometric realization P=|K| a resolution R(X,K) of X×P, which consists of paracompact spaces. If X consists of compact polyhedra, then R(X,K) consists of spaces having the homotopy type of polyhedra. In two subsequent papers the author proved that R(X,K) is a covariant functor in each of its variables X and K. In the present paper it is proved that R(X,K) is a bifunctor. Using this result, it is proved that the Cartesian product X×Z of a compact Hausdorff space X and a topological space Z is a bifunctor SSh(Cpt)×Sh(Top)→Sh(Top) from the product category of the strong shape category of compact Hausdorff spaces SSh(Cpt) and the shape category Sh(Top) of topological spaces to the category Sh(Top). This holds in spite of the fact that X×Z need not be a direct product in Sh(Top)
Model experiments on jack-up platform hydrodynamics
No full textExperiments in a physical model to measure forces in the joints and displacements of the nodes in the structure as effect of wave action.Marine & Transport TechnologyMechanical, Maritime and Materials Engineerin
- …
