The GEO 600 laser system

Interferometric gravitational wave detectors require high optical power, single frequency lasers with very good beam quality and high amplitude and frequency stability as well as high long-term reliability as input light source. For GEO 600 a laser system with these properties is realized by a stable planar, longitudinally pumped 12 W Nd:YAG rod laser which is injection-locked to a monolithic 800 mW Nd:YAG non-planar ring oscillator. Frequency control signals from the mode cleaners are fed to the actuators of the non-planar ring oscillator which determines the frequency stability of the system. The system power stabilization acts on the slave laser pump diodes which have the largest influence on the output power. In order to gain more output power, a combined Nd:YAGNd:YVO4 system is scaled to more than 22 W

Predicting color and short-circuit current of colored BIPV modules

Photovoltaic modules for façade integration should have a widely modifiable appearance to adjust to the architect’s requirements. However, architects today usually have only a limited number of already manufactured samples to choose from. Changing the color will also change the photovoltaic yield. Therefore, it would be helpful to have a procedure that allows us to determine the appearance and expected yield in advance of module fabrication. We present such a method for creating a digital prototype of a colored building integrated photovoltaic module. Using reflectance and external quantum efficiency measurements of eight colored modules, we simulate the appearance and respective energy yield for arbitrary module colors. We validate our predictions for 29 different colored modules. We use textiles that have been colored by printing and laminate them onto the modules to change the appearance of the modules. However, our digital prototyping model is also applicable to other coloring techniques. We achieve an average color difference of ΔE00 = 1.34 between predicted and measured colors, which is barely perceptible to the human eye. The predicted short-circuit current density of the digital prototype deviates on average less than 1% from the measured on

A Cryptographic Analysis of the WireGuard Protocol

WireGuard (Donenfeld, NDSS 2017) is a recently proposed secure network tunnel operating at layer 3. WireGuard aims to replace existing tunnelling solutions like IPsec and OpenVPN, while requiring less code, being more secure, more performant, and easier to use. The cryptographic design of WireGuard is based on the Noise framework. It makes use of a key exchange component which combines long-term and ephemeral Diffie-Hellman values (along with optional preshared keys). This is followed by the use of the established keys in an AEAD construction to encapsulate IP packets in UDP. To date, WireGuard has received no rigorous security analysis. In this paper, we, rectify this. We first observe that, in order to prevent Key Compromise Impersonation (KCI) attacks, any analysis of WireGuard\u27s key exchange component must take into account the first AEAD ciphertext from initiator to responder. This message effectively acts as a key confirmation and makes the key exchange component of WireGuard a 1.5 RTT protocol. However, the fact that this ciphertext is computed using the established session key rules out a proof of session key indistinguishability for WireGuard\u27s key exchange component, limiting the degree of modularity that is achievable when analysing the protocol\u27s security. To overcome this proof barrier, and as an alternative to performing a monolithic analysis of the entire WireGuard protocol, we add an extra message to the protocol. This is done in a minimally invasive way that does not increase the number of round trips needed by the overall WireGuard protocol. This change enables us to prove strong authentication and key indistinguishability properties for the key exchange component of WireGuard under standard cryptographic assumptions

Enzymfreisetzung und Aktivierung der Kallikrein-Kinin-Systeme bei experimenteller Pankreatitis

Das klinische Bild der akuten Pankreatitis wird entscheidend durch die sekundäre Schädigung von Herz-Kreislauf-System, Lunge und Niere bestimmt. Ziel der vorliegenden Untersuchung war es, durch Messungen in venösem Pankreasblut, Pankreaslymphe und Peritonealexsudat die Kompartimente zu bestimmen, über die die systemischen Schädigungen vermittelt werden. An anästhesierten Schweinen wurden die systemischen, hämodynamischen Parameter durch gesteuerte Volumentherapie konstant gehalten. Die Schweine wurden randomisiert der Kontrollgruppe (n = 9) oder einer der Pankreatitisgruppen zugeteilt (jeweils n = 10). Die Pankreatitis wurde durch Infusion von freier Fettsäure in die Pankreasarterien (FFS) oder durch Infusion einer 5%igen Natrium-Taurocholat-Lösung retrograd in den Pankreasgang (NaT) ausgelöst. Nach Isolation des Pankreas wurde venöses Pankreasblut, Pankreaslymphe und Peritonealexsudat gewonnen und die Aktivität von Lipase, Phospholipase A und Plasmaprokallikrein sowie die Konzentration von Organkallikrein und Kininogen bestimmt. In beiden Pankreatitismodellen fand sich ein Anstieg der Enzymaktivitäten. Die höchsten Aktivitäten fanden sich im Peritonealexsudat (Phospholipase A nach 40 min: Kontrolle 10,0 U/1, NaT 72,2 U/1). In beiden Pankreatitismodellen fanden sich außerdem Hinweise für eine Aktivierung des Organkallikrein-Kinin-Systems durch den Anstieg der Organkallikreinkonzentration und den Abfall der Gesamtkininogenkonzentration. Die stärksten Veränderungen fanden sich wieder im Peritonealexsudat (Organkallikrein nach 40 min: Kontrolle 14,7 ng/ml, NaT 452 ng/ml).The clinical course of acute pancreatitis is strongly influenced by secondary cardiac, pulmonary and renal damage. The aim of the present study was to gather information about the compartment promoting the systemic damage. Therefore the activity of lipase, phospholipase A and plasmaprokallikrein and the concentration of tissue kallikrein and kininogen were measured in portal venous blood, pancreatic lymph and peritoneal exudate. Anaesthetized pigs were subjected to fluid resuscitation to keep systemic haemodynamic parameters constant. The pancreas was isolated in situ. The pigs were randomly assigned to a control group (n = 9) or one of the two pancreatitis groups (n = 10 each). Pancreatitis was induced by i.a. infusion of free fatty acid (FFS) or retrograde infusion of 5 % sodium taurocholate intraductally (NaT). In both pancreatitis groups the activity of lipase and phospholipase A increased. The most pronounced changes were seen in the peritoneal exsudate (phospholipase A activity 40 min after induction: control 10.0 U/1, NaT 72.2 U/1). In both pancreatitis groups there was evidence for activation of the tissue kallikreinkinin system in the form of an increase in the kallikrein concentration and a decrease in the kininogen concentration. Again the changes were most pronounced in the peritoneal exsudate (tissue kallikrein 40 min after induction: control 14.7 ng/ml, NaT 452 ng/ml)

Linear Optical CNOT Gate in the Coincidence Basis

We describe the operation and tolerances of a non-deterministic, coincidence basis, quantum CNOT gate for photonic qubits. It is constructed solely from linear optical elements and requires only a two-photon source for its demonstration.Comment: Submitted to Physical Review

Advances in the Surface Passivation of Silicon Solar Cells

AbstractThe surface passivation properties of aluminium oxide (Al2O3) on crystalline Si are compared with the traditional passivation system of silicon nitride (SiNx). It is shown that Al2O3 has fundamental advantages over SiNx when applied to the rear of p-type silicon solar cells as well as to the p+ emitter of n-type silicon solar cells. Special emphasis is paid to the transfer of Al2O3 into industrial solar cell production. We compare different Al2O3 deposition techniques suitable for mass production such as ultrafast spatial atomic layer deposition, inline plasma-enhanced chemical vapour deposition and reactive sputtering. Finally, we review the most recent cell results with Al2O3 passivation and give a brief outlook on the future prospects of Al2O3 in silicon solar cell production

Energy-time entanglement of quasi-particles in solid-state devices

We present a proposal for the experimental observation of energy-time entanglement of quasi-particles in mesoscopic physics. This type of entanglement arises whenever correlated particles are produced at the same time and this time is uncertain in the sense of quantum uncertainty, as has been largely used in photonics. We discuss its feasibility for electron-hole pairs. In particular, we argue that the recently fabricated 2DEG-2DHG junctions, irradiated with a continuous laser, behave as "entanglers" for energy-time entanglement.Comment: 4 pages, 3 figure