253 research outputs found
Crucible-free Pulling of Germanium Crystals
Commonly, germanium crystals are grown after the Czochralski (CZ) method. The
crucible-free pedestal and floating zone (FZ) methods, which are widely used
for silicon growth, are hardly known to be investigated for germanium. The
germanium melt is more than twice as dense as liquid silicon, which could
destabilize a floating zone. Additionally, the lower melting point and the
related lower radiative heat loss is shown to reduce the stability especially
of the FZ process with the consequence of a screw-like crystal growth. We found
that the lower heat radiation of Ge can be compensated by the increased
convective cooling of a helium atmosphere instead of the argon ambient. Under
these conditions, the screw-like growth could be avoided. Unfortunately, the
helium cooling deteriorates the melting behavior of the feed rod. Spikes appear
along the open melt front, which touch on the induction coil. In order to
improve the melting behavior, we used a lamp as a second energy source as well
as a mixture of Ar and He. With this, we found a final solution for growing
stable crystals from germanium by using both gases in different parts of the
furnace. The experimental work is accompanied by the simulation of the
stationary temperature field. The commercially available software FEMAG-FZ is
used for axisymmetric calculations. Another tool for process development is the
lateral photo-voltage scanning (LPS), which can determine the shape of the
solid-liquid phase boundary by analyzing the growth striations in a lateral cut
of a grown crystal. In addition to improvements of the process, these
measurements can be compared with the calculated results and, hence, conduce to
validate the calculation.Comment: 4 pages, 10 figures, ICCG-1
Growth Angle and Melt Meniscus of the RF-heated Floating Zone in Silicon Crystal Growth
This article presents a direct measurement of the growth angle during the
growth of a cylindrical 2" silicon crystal using a radio-frequency heated
floating zone process. From the high-resolution pictures taken during the
process, this growth angle was evaluated to be 11{\deg}{\pm}2{\deg}.
Furthermore, the free surface of the melt was modeled using the Laplace-Young
equation. This model has to include the electromagnetic pressure calculated by
the surface ring currents approximation. The results were compared to the
experimental free surface derived from video frames. It could be shown that the
calculated free surface will only fit the experimentally determined one if the
right growth angle is considered
Tibull in Russland zur produktiven rezeption der elegie i 1 in Russland am beginn des 19. jahrhunderts
At the beginning of the 19th century, there was an intensive productive reception of the Corpus Tibullianum in Russian poetry, particularly of Tibullus’ elegy I 1. By analyzing the titles, the notes, and selected aspects of the main text of the six Russian translations of the elegy, Oraić Tolić’s Romantic notion of the paradigm shift from “illustrative” to “illuminative” quotation can be seen. However, this change does not take place in a linear fashion: Although the change in the titles and notes occurs in a consequential manner, the main texts meander between the stated poles
Inkjet printed paper based frequency selective surfaces and skin mounted RFID tags: the interrelation between silver nanoparticle ink, paper substrate and low temperature sintering technique
Inkjet printing of functional frequency selective surfaces (FSS) and radio frequency identification (RFID) tags on commercial paper substrates using silver nanoparticle inks sintered using low temperature thermal, plasma and photonic techniques is reported. Printed and sintered FSS devices demonstrate performances which achieve wireless communication requirements having a forward transmission scattering parameter, S21, depth greater than ?20 dB at 13 GHz. Printed and plasma sintered RFID tags on transfer paper, which are capable of being mounted on skin, improved read distances compared to previously reported single layer transfer RFID tags fabricated by conventional thermal sintering
Klinisches Outcome von Patientinnen und Patienten mit ICD-Implantation ab dem 75. Lebensjahr
Introduction: Until today the ICD is the most effective treatment of life-threatening ventricular tachyarrhythmia and is presently often used even in the group of older patients. Objective in this study was to have a close look on 75 plus patients, who had a primary or secondary preventive ICD im-plantation. Life shortening comorbidities, number of shocks released, the influence of age and gender and unintended events in context with ICD placing are the key topics.
Methods: This retrospective evaluation examines a group of 105 women and men, who underwent primary and secondary preventive ICD insertion in the Charité – university hospital in Berlin between 2005 and 2015. Patients under 75 and after upgrading to CRT were excluded from the study. The patient files were investigated for comorbidities and predictors of early mortality were defined. Spe-cial emphasis was put on patients who survived more than five years and those with appropriate ICD therapy. Adverse effects and especially events requiring revision procedures were identified.
Results: The study group consisted of 27.6 % women and 72,3 % men, who received an ICD in the age from 75 to 89 years and got a follow up for 3.16 ± 2.59 years. 46.6 % of the patients died and 46.6 % survived, while 6.6 % remained unclear due to follow up problems. On the whole 60,00 % of the ICDs were primary and 40,00 % secondary preventive implanted. In 82,8 % coronary heart disease was the main reason for cardiomyopathy. Male gender (HR 6,15; 95 % CI 1,26-29,99; p = 0.025) and NYHA grade 3 and 4 (HR 5,63; 95 % CI 1,36-23,25; p = 0.017) are independent risk factors for early mortality. Further predictors are kidney failure (HR 2,02; 95 % CI 1,11-3,67; p = 0.021), acute heart failure (HR 3,10; 95 % CI 1,45-6,61; p = 0.003) and ventricular fibrillation (HR 2,96; 95 % CI 1,35-6,49; p = 0.007) before ICD implantation. 22,86 % of the patients received an ICD therapy in the named period. 9,52 % suffered from inappropriate ICD shocks. Rare events were lead infections (1,9 %), lead dislocations (2,86 %) and pneumothorax (3,8 %). 5,71 % of all complications required revision surgery.
Conclusion: High age should not be a single excluding criterion for ICD implantation considering a low rate of complications and a similar therapeutic effect in these patients. Especially for people with low comorbidities the data show sufficient evidence for beneficial ICD implantation if precisely indicated.Einleitung: Der Implantierbare Kardioverter-Defibrillator (ICD) ist bislang die effektivste Therapiemöglichkeit
bei lebensbedrohlichen ventrikulären Tachyarrhythmien und wird heutzutage immer
häufiger bei einem älteren Patientenkollektiv eingesetzt. Ziel dieser Studie ist es primär- und
sekundärpräventiv implantierte Patienten mit einem ICD ab dem 75. Lebensjahr näher zu untersuchen.
Schwerpunkte liegen auf die Lebensdauer beeinflussende Komorbiditäten, stattgehabten
ICD-Therapien, dem Einfluss von Alter und Geschlecht sowie unerwünschten Ereignissen im Zusammenhang
mit der Implantation.
Methodik: Diese retrospektive Datenauswertung untersucht ein Kollektiv aus 105 Männern und
Frauen, welche zwischen 2005 und 2015 primär- oder sekundärpräventiv in der Charité – Universitätsmedizin
Berlin mit einem ICD versorgt wurden. Voraussetzung zum Studieneinschluss war ein
Mindestalter von 75 Lebensjahren. Personen mit einer Kardialen Resynchronisationstherapie (CRT)
wurden ausgeschlossen. Anhand der Patientenakten konnten Informationen zu Komorbiditäten
gewonnen und Prädiktoren für ein vorzeitiges Versterben ermittelt werden. Darüber hinaus wurden
die Subgruppen der Langzeitüberlebenden über 5 Jahre und Personen mit adäquaten ICDTherapien
untersucht. Auch unerwünschte Ereignisse, insbesondere mit nötigen Revisionseingriffen,
sind erfasst worden.
Ergebnisse: Das untersuchte Kollektiv besteht aus 27,62 % Frauen und 72,38 % Männern, welche
bei einer Altersspanne von 75 bis 89 Jahren implantiert und 3,16 ± 2,59 Jahre nachverfolgt wurden.
46,67 % des Kollektivs verstarb innerhalb dieses Zeitraums, ebenfalls 46,67 % sind zum Studienende
am Leben und 6,67 % verbleiben unklar. Insgesamt wurden 60,00 % der Kohorte primärpräventiv
und 40,00 % sekundärpräventiv implantiert. Die Koronare Herzkrankheit (KHK) bildet
bei 82,86 % die häufigste Ursache für eine Kardiomyopathie. Das männliche Geschlecht (Hazard
Ratio [HR] 6,15; 95 % CI 1,26-29,99; p = 0.025) sowie die New York Heart Association [NYHA]-
Stadien 3 und 4 (HR 5,63; 95 % CI 1,36-23,25; p = 0.017) sind unabhängige Risikofaktoren für ein
früheres Versterben. Ebenfalls als unabhängige Prädiktoren sind eine Niereninsuffizienz (HR 2,02;
95 % CI 1,11-3,67; p = 0.021), eine kardiale Dekompensation (HR 3,10; 95 % CI 1,45-6,61;
p = 0.003) sowie Kammerflimmern (HR 2,96; 95 % CI 1,35-6,49; p = 0.007) vor der Implantation
zu nennen. 22,86 % der Patienten erhielten eine ICD-Therapie im beschriebenen Zeitraum. 9,52 %
erfuhren dabei als unerwünschtes Ereignis eine inadäquate Auslösung des Defibrillators. Seltenere
Ereignisse waren Sondeninfektionen (1,90 %), Sondendislokationen (2,86 %), notwenige Revisionseingriffe
(5,71 %) oder Pneumothoraxes (3,81 %). Schlussfolgerung: Nur das fortgeschrittene Alter sollte kein Ausschlusskriterium für eine ICDImplantation
sein, vor allem da die Komplikationsrate eher gering einzuschätzen ist und die therapeutischen
Vorteile nicht abschwächt werden. Insbesondere bei überschaubaren Komorbiditäten
scheint die Datenlage für eine Implantation bei vorliegender Indikation auszureichen
Inkjet Fabrication of Frame Dipole FSS
Digital fabrication techniques gives the possibility of producing elements with very thin and precise features which could allow the modification of UHF structures to reduce ink usage while still achieving similar performance. This paper investigates the case where dipole elements are modified into Frame Dipoles by removing areas where the surface current tends to be very low
MULTISENSORY DLA BIOSENSORÓW PEŁNOKOMÓRKOWYCH
Whole-cell biosensors, which can be used in the environmental protection and process measuring technology, in the biotechnology, food and pharmaceutical industry for the on-line control and monitoring of chemical and biochemical processes and for the fast detection of small amounts of solutes, are of great interest. These kind of biosensors comprise microorganisms like genetically modified yeast cells, which react on a specific stimulus, e.g. a residual amount of drugs in the measurement medium with a dependent fluorescence. The receptors of the cells detect specific signal molecules and stimulate the organism to produce a fluorescent protein. In this work, a combined impedimetric-optical read out was used, which can provide the reliable and long-term stable detection of a fluorescence signal accompanied by impedance measurements monitoring cell vitality and activity. A new challenge thereby is a special sensor design which enables the integration of excitation source, photodetector, interdigitated electrodes, and the fluidic system with an effective and long-term-stable packaging.Biosensory pełnokomórkowe cieszą się bardzo dużym zainteresowaniem. Mogą one być wykorzystywane w ochronie środowiska i technologii pomiaru procesów, w branży biotechnologicznej, spożywczej i farmaceutycznej do kontrolowania i monitorowania procesów chemicznych i biochemicznych on-line oraz do szybkiego wykrywania niewielkich ilości substancji rozpuszczonych,. Tego rodzaju biosensory obejmują mikroorganizmy, takie jak genetycznie zmodyfikowane komórki drożdży, które reagują na specyficzny bodziec, np. fluorescencją na resztkowa ilość leków w pożywce pomiarowej. Receptory komórek wykrywają określone cząsteczki sygnałowe i stymulują organizm do wytwarzania białka fluorescencyjnego. W pracy wykorzystano łączony odczyt impedancyjno-optyczny, który może zapewnić niezawodną i długotrwale stabilną detekcję sygnału fluorescencyjnego, któremu towarzyszą pomiary impedancji monitorujące żywotność i aktywność komórek. Nowym wyzwaniem jest specjalna konstrukcja czujnika, która umożliwia integrację źródła pobudzenia, fotodetektora, elektrod palcowych i układu płynowego w jednej obudowie
Significant Factors in the Inkjet Manufacture of Frequency Selective Surfaces
Additive fabrication of electromagnetic structures by inkjet printing technology is both cost effective and compatible with a wide range environmentally-friendly substrates, enabling fabrication of frequency selective surface arrays with line dimensions less than 0.1 mm; difficult to achieve with conventional subtractive techniques. Several approaches have been investigated in order to produce low-cost frequency selective panels with acceptable level of isolation, such as savings in ink by depositing it at the edges of dipole elements where the surface current tends to maximize. The FSS transmission characteristics were improved by jetting multiple ink layers on the whole elements and at the edges. The electrical resistance of various arrays have been measured and analysed and has been used to assess the performances of the FSS
Payments for ecosystem services in the tropics: a closer look at effectiveness and equity
We undertake a review of academic literature that examines the effectiveness and equity-related performance of PES initiatives targeting biodiversity conservation in tropical and sub-tropical countries. We investigate the key features of such analyses as regards their analytical and methodological approach and we identify emerging lessons from PES practice, leading to a new suggested research agenda. Our results indicate that analyses of PES effectiveness have to date focused on either ecosystem service provision or habitat proxies, with only half of them making explicit assessment of additionality and most describing that payments have been beneficial for land cover and biodiversity. Studies evaluating the impact of PES on livelihoods suggest more negative outcomes, with an uneven treatment of the procedural and distributive considerations of scheme design and payment distribution, and a large heterogeneity of evaluative frameworks. We propose an agenda for future PES research based on the emerging interest in assessing environmental outcomes more rigorously and documenting social impacts in a more comparative and contextually situated form
Conservation conflicts:Behavioural threats, frames, and intervention recommendations
Conservation conflicts are widespread and are damaging for biodiversity, livelihoods and human well-being. Conflict management often occurs through interventions targeting human behaviour. Conservation interventions are thought to be made more effective if underpinned by evidence and a Theory of Change – a logical argument outlining the steps required to achieve goals. However, for conservation conflicts, the evidence and logic supporting different types of interventions has received little attention. Using conflict-related keywords, we reviewed trends in behavioural intervention recommendations across conflict contexts globally, as published in peer-reviewed literature. We developed typologies for conflict behaviours, intervention recommendations, and conflict frames and identified associations between them and other geographical variables using Pearson's Chi-squared tests of independence. Analysing 100 recent articles, we found that technical interventions (recommended in 38% of articles) are significantly associated with conflicts involving wildlife control and the human-wildlife conflict frame. Enforcement-based interventions (54% of articles) are significantly associated with conflicts over illegal resource use, while stakeholder-based interventions (37% of articles) are associated with the human-human conflict frame and very highly developed countries. Only 10% of articles offered “strong” evidence from the published scientific literature justifying recommendations, and only 15% outlined Theories of Change. We suggest that intervention recommendations are likely influenced by authors' perceptions of the social basis of conflicts, and possibly also by disciplinary silos
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