12 research outputs found
InAs-based interband-cascade-lasers emitting around 7 μm with threshold current densities below 1 kA/cm2 at room temperature
No full textThe authors acknowledge the financial support from the European Commission in the frame of the FP7 project “WideLase” (Grant No. 318798) Date of Acceptance: 19/01/2015Interband cascade lasers (ICLs) grown on InAs substrates with threshold current densities below 1 kA/cm2 are presented. Two cascade designs with different lengths of the electron injector were investigated. Using a cascade design with 3 InAs quantum wells (QWs) in the electron injector, a device incorporating 22 stages in the active region exhibited a threshold current density of 940 A/cm2 at a record wavelength of 7 μm for ICLs operating in pulsed mode at room temperature. By investigating the influence of the number of stages on the device performance for a cascade design with 2 QWs in the electron injector, a further reduction of the threshold current density to 800 A/cm2 was achieved for a 30 stage device.Peer reviewe
Submonolayer uniformity of type II InAs/GaInSb W-shaped quantum wells probed by full-wafer photoluminescence mapping in the mid-infrared spectral range
No full textThe work has been supported by Project Widelase (No. 318798) of the 7-th Framework Program of the European Commission. Date of Acceptance: 06/10/2015The spatial uniformity of GaSb- and InAs substrate-based structures containing type II quantum wells was probed by means of large-scale photoluminescence (PL) mapping realized utilizing a Fourier transform infrared spectrometer. The active region was designed and grown in a form of a W-shaped structure with InAs and GaInSb layers for confinement of electrons and holes, respectively. The PL spectra were recorded over the entire 2-in. wafers, and the parameters extracted from each spectrum, such as PL peak energy position, its linewidth and integrated intensity, were collected in a form of two-dimensional spatial maps. Throughout the analysis of these maps, the wafers' homogeneity and precision of the growth procedure were investigated. A very small variation of PL peak energy over the wafer indicates InAs quantum well width fluctuation of only a fraction of a monolayer and hence extraordinary thickness accuracy, a conclusion further supported by high uniformity of both the emission intensity and PL linewidth.Peer reviewe
Towards “Government as a Platform”: An analysis framework for public sector infrastructure
No full text“Government as a Platform” (GaaP) is a promising approach to the digital transformation of the public sector. The approach sees Government as an open platform on which people inside and outside the government can innovate and co-create better public services. On a technical level, this is enabled by public sector infrastructure that also follows the approach. However, it remains unclear how exactly GaaP can be applied to public sector infrastructure in practice. In order to tackle this challenge, we develop a framework for the analysis of public infrastructure regarding its platform character. We apply the framework to a current public infrastructure project in Germany to demonstrate its applicability and infer possible future improvements. We contribute to literature by integrating GaaP literature with ideas and concepts from general IS platform literature and contribute to practice by providing a tool that supports the application of GaaP
CNTF and CNTF receptor alpha are constitutively expressed by astrocytes in the mouse brain
No full textBeing on Sick Leave – Possible Explanations for Differences of Sick-leave Days AcrossCountries Privatization
No full textSick-leave days differ widely among industrialised countries. For the US it is 5, for Sweden 20 and for Poland 26 days per year and per employee. The possible causes for these differences have apparently not been systematically analysed. Two groups of contributing factors are considered: (1) natural causes, like the general health situation, employment of women and older persons, and (2) behavioural reactions (a) to macroeconomic conditions,like unemployment or the possibility to work outside the official labour market, and (b) to the design of institutions, like the generosity of granting sick leave. On the basis of 20 countries it is econometrically shown that the main explanatory factors are: generosity of granting sick leave, opportunity costs due to income differentials with neighbouring states, and employment of older people. The unemployment rate – contrary to the result of some single-country studies – and the employment of women do not contribute to theexplanation of sick-leave differences between countries.
Shortened injector interband cascade lasers for 3.3-to 3.6-mu m emission
No full textInterband cascade lasers (ICLs) are very attractive light sources to cover the important spectral range from 3.3 to 3.6 mu m, which is of major interest for hydrocarbon detection. We present ICLs emitting in this wavelength range that have a notably shortened injector region. Compared to a well-established reference design, the total length of one cascade is reduced by about 16% to only 63 nm. The benefits are a reduction of the number of heterointerfaces, a higher intensity of the optical mode in the active region, and easier strain compensation. Threshold current densities of devices using the new injector design are cut in half throughout the temperature range of operation, compared to devices with the reference design. Deeply etched ridge waveguide devices processed from structures with 14 cascades yielded maximum operation temperatures of 73 degrees C in pulsed operation. Peak output powers exceed 100 mW at a heat-sink temperature of 15 degrees C. (C) 2010 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3505831]</p
Fourier Transformed Photoreflectance and Photoluminescence of Mid Infrared GaSb-Based Type II Quantum Wells
No full textFourier-transformed photoreflectance and photoluminescence have been used to study the optical transitions in type 11 quantum wells (QWs) ranging up to almost 5 mu m. High signal-to-noise ratio spectral features resulting from fundamental and excited state transitions have been detected for molecular beam epitaxially grown GaSb/AlSb/InAs/InGaSb/InAs/AlSb/GaSb "W"-shaped QW structures designed for laser-based gas sensing applications in the mid-infrared. The spectral features' dependence on arsenic pressure during growth process and on InAs confining-layer thickness could be followed unambiguously at room temperature. (C) 2009 The Japan Society of Applied Physics DOI: 10.1143/APEX.2.126505</p
The @impact of the Ahr Valley flood on the health of the local population – an analysis based on SHI routine data
No full textHintergrund:
In den letzten Jahrzehnten traten in Deutschland Hochwasserereignisse auf, die eine Bedrohung für die Gesundheit der lokalen Bevölkerung darstellten. Es existieren allerdings kaum Studien, die die gesundheitlichen Folgen dieser Ereignisse untersuchen. Studienziel war daher die Untersuchung der Assoziationen des Ahrtal-Hochwassers im Jahr 2021 mit der Gesundheit der lokalen Bevölkerung.
Methoden:
Datengrundlage dieser Studie sind bundesweite Abrechnungsdaten (stationär/ambulant) des BKK-Landesverbands Nordwest. Untersuchungsregion war die Region Ahrweiler, Untersuchungszeiträume jeweils das 3. Quartal der Jahre 2020 und 2021. Unter anderem mit Prevalence-Rate-Ratio-Tests wurde auf Grundlage von ICD-10-Kodierungen untersucht, welche Diagnosen (stationär/ambulant) räumlich und zeitlich in Assoziation mit dem Hochwasserereignis standen.
Ergebnisse:
Die Ergebnisse zeigen im stationären Bereich eine deutliche Zunahme abgerechneter Leistungen in einigen Diagnosegruppen gegenüber dem Vorjahr. Verzeichnet wurden insbesondere Zunahmen bestimmter F‑Diagnosen (psychische und Verhaltensstörungen) und S‑Diagnosen (Verletzungen) sowie verschiedener Diagnoseschlüssel innerhalb der Z‑Kodierungen (Faktoren, die den Gesundheitszustand beeinflussen und zur Inanspruchnahme des Gesundheitswesens führen). Im ambulanten Sektor wurde in vielen Diagnosegruppen (F- und Z‑Diagnosen) eine Abnahme identifiziert.
Diskussion:
Die Ergebnisse der Studie deuten darauf hin, dass vor allem die mentale Gesundheit der lokalen Bevölkerung und die Gesundheitsversorgung insgesamt (sektorspezifische Inanspruchnahme) vom Hochwasser beeinträchtigt wurden. Da Hochwasserereignisse zukünftig häufiger und stärker werden können, müssen die Maßnahmen zum Schutz der Bevölkerung und Gesundheitsinfrastruktur entsprechend angepasst werden
