Search results for "Long period"
showing 10 items of 50 documents
Charge compensation by long-period reconstruction in strongly polar lithium niobate surfaces
2013
The microscopic structure of the polar (000$\overline{1}$) and (0001) surfaces of lithium niobate is investigated by atomic-resolution frequency modulation atomic force microscopy and first-principles calculations. It is found that the surface reconstructs at annealing temperatures sufficiently high to drive off external adsorbates. In particular a ($\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{7}$)$R$19.1${}^{\ensuremath{\circ}}$ reconstruction is found for the (000$\overline{1}$) surface. Density-functional theory calculations show that---apart from the $(\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{7})$---a series of adatom-induced surface reconstructions exist that lower the surfa…
Characteristics of current roadside pollution using test-monitoring plots
2014
Abstract The aim of the study was the qualitative recognition of the existing roadside pollutants deposited in topsoils located close to roads with high traffic volume. So far, the studies have helped to determine the content of pollutants that accumulated over a long period of time. Traditionally, it has been difficult to distinguish between roadside pollution and pollution from other industrial sources. In order to avoid such problems and to accurately recognize present threats originating from road traffic, test-monitoring plots were installed in Poland (Gliwice and Opole), Germany (Tubingen, Ulm and Boblingen), Finland (Helsinki), Tajikistan (Dushanbe) and China (Lanzhou). To install th…
Die Best�ndigkeit der Eiweissfraktionen und Fermente in lange gelagerten menschlichen Serumkonserven
1951
Die Untersuchung von 8 flussigen Serumkonserven, wie sie im Kriege als Blutersatzmittel verwendet und die 5–6 Jahre bei Zimmertemperatur gelagert worden waren, ergab:
Continuities and Discontinuities in the Economic Growth of Spain. 1850-1936
1998
The Spanish pattern of economic growth during the last two centuries is quite unique. In the nineteenth century, Spain remained outside the process of industrialization, but during the twentieth century it has joined the small group of developed economies. This article checks the possible existence of discontinuities between 1850-1936 in the series of PNB, industrial production and private and public investment by utilizing recent developments in the econometric analysis associated with the work of Perron and Ziwot and Andrews. The results confirm the continuity of the Spanish growth during the long period considered. However, they also show two breakpoint years: 1870 in the series of indus…
Study of the long-period changes in samples of isotactic poly(propylene) obtained by quenching from the melt and subsequent annealing at different te…
1997
The structural modifications induced in samples of isotactic poly(propylene) obtained by quenching from the melt at 100°C/s and subsequently annealed at 40, 60 and 80°C for different annealing times have been studied using simultaneous wide-angle and small-angle X-ray scattering at the synchrotron radiation source of DESY. The occurrance of two different long-period values is demonstrated. These values are related to the mesomorphic phase, existing in the starting quenched material, and to the α-monoclinic one, which settles during the annealing process, respectively.
Synthese und eigenschaften von einem nitrosubstituierten p-polyphenylen und von nitrosubstituierten p-oligophenylenen. 15. Mitteilung1
1964
Bei aromatischen Nitrojodverbindungen nimmt die ULLMANN-Reaktion unter verhaltnismasig milden Bedingungen einen praktisch quantitativen Verlauf, wenn sich das Jod in der o-Stellung zu einer Nitrogruppe befindet. Mit einer entsprechenden bifunktionellen Verbindung, dem 4,4′-Dijod-3,3′-dinitrobiphenyl, konnte unter den gleichen Bedingungen ein nitrosubstituiertes p-Polyphenylen erhalten werden, ein hellgelbes, unlosliches und unschmelzbares Pulver, das sich bei hoherer Temperatur (> 250°C) zersetzt. Auf Grund des Jodgehaltes (Endgruppen) wurde ein mittlerer Kondensationsgrad von 52 berechnet; das entspricht einer p-Phenylenkette aus 104 Benzolringen. Das Polymere ist kristallin und besitzt ei…
Human primary macrophages scavenge AuNPs and eliminate it through exosomes. A natural shuttling for nanomaterials.
2018
Abstract The use of nanomaterials is increasing but the real risk associated with their use in humans has to be defined. In fact, nanomaterials tend to accumulate in organs over a long period of time and are slowly degraded or eliminated by the body. Exosomes are nanovesicles actively shuttle molecules, including chemical products and metals, through the body. Macrophages scavenge the body from both organic and inorganic substances, and they use to release high amounts of exosomes. We hypothesized that macrophages may have a role in eliminating nanomaterials through their exosomes. We treated human primary macrophages with 20 nm gold nanoparticles (AuNPs), analyzing the presence of AuNPs in…
Monochromatic Long-Period Seismicity Prior to the 2012 Earthquake Swarm at Little Sitkin Volcano, Alaska
2021
Detection of the earliest stages of unrest is one of the most challenging and yet critically needed aspects of volcano monitoring. We investigate a sequence of five unusual long-period (LP) earthquakes that occurred in the days prior to the onset of a months-long volcano-tectonic (VT) earthquake swarm beneath Little Sitkin volcano in the Aleutian Islands during late 2012. The long-period earthquakes had two distinctive characteristics: their signals were dominated by a monochromatic spectral peak at approximately 0.57 Hz and they had impulsive P and S-wave arrivals on a seismometer located on Amchitka Island 80 km to the southeast of the volcano. In each case, the monochromatic earthquakes …
Pinger affects fish catch efficiency and damage to bottom gill nets related to bottlenose dolphins
2009
There is some evidence that the presence of Tursiops truncatus in fishing areas represents a real economic threat to fishermen due the dolphin feeding on the entangled fish, damaging the nets and reducing the fish catch. We have carried out experiments to assess the efficiency of a pinger in decreasing the interaction between the dolphins and fishing nets, in a fishing area off the coast of southern Italy, where Tursiops truncatus is frequently observed to interact with bottom gill nets. Two identical monofilament bottom gill nets (900 m long), one equipped with pingers and the other without, were used to measure the effect of these pingers on the abundance of the catch and net damage. For …
Thyroid sarcoidosis as a unique localization.
2006
Sarcoidosis is a systemic disorder characterized by granulomatous lesions, principally affecting the lungs. There are numerous reports in the literature of an associated involvement of the thyroid, much more frequently in hypothyroid than in hyperthyroid subjects. The present case report refers to a woman presenting with thyroid nodules and normal biochemical levels and thyroid function parameters, while histology revealed sarcoid-type lesions. Subsequent investigations and a long follow-up showed no evidence of involvement of other sites, including the lungs. Consequently, after a long period of normal health associated with the negative results of the examinations, a diagnosis of sarcoido…