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排序方式: 共有719条查询结果,搜索用时 437 毫秒
11.
Lukas Schäfer Konstantin Skokov Fernando Maccari Iliya Radulov David Koch Andrey Mazilkin Esmaeil Adabifiroozjaei Leopoldo Molina-Luna Oliver Gutfleisch 《Advanced functional materials》2023,33(4):2208821
Permanent magnets based on neodymium-iron-boron (Nd-Fe-B) alloys provide the highest performance and energy density, finding usage in many high-tech applications. Their magnetic performance relies on the intrinsic properties of the hard-magnetic Nd2Fe14B phase combined with control over the microstructure during production. In this study, a novel magnetic hardening mechanism is described in such materials based on a solid-state phase transformation. Using modified Nd-Fe-B alloys of the type Nd16Febal-x-y-zCoxMoyCuzB7 for the first time it is revealed how the microstructural transformation from the metastable Nd2Fe17Bx phase to the hard-magnetic Nd2Fe14B phase can be thermally controlled, leading to an astonishing increase in coercivity from ≈200 kAm−1 to almost 700 kAm−1. Furthermore, after thermally treating a quenched sample of Nd16Fe56Co20Mo2Cu2B7, the presence of Mo leads to the formation of fine FeMo2B2 precipitates, in the range from micrometers down to a few nanometers. These precipitates are responsible for the refinement of the Nd2Fe14B grains and so for the high coercivity. This mechanism can be incorporated into existing manufacturing processes and can prove to be applicable to novel fabrication routes for Nd-Fe-B magnets, such as additive manufacturing. 相似文献
12.
Weber Lukas Vinon Tobias Kndler Christian Solis-Vasquez Leonardo Bernhardt Arthur Petrov Ilia Koch Andreas 《Distributed and Parallel Databases》2022,40(1):27-45
Distributed and Parallel Databases - Massive data transfers in modern data-intensive systems resulting from low data-locality and data-to-code system design hurt their performance and scalability.... 相似文献
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Aibek Sarimbekov Lukas Stadler Lubomír Bulej Andreas Sewe Andrej Podzimek Yudi Zheng Walter Binder 《Software》2016,46(8):1053-1089
Originally developed with a single language in mind, the JVM is now targeted by numerous programming languages—its automatic memory management, just‐in‐time compilation, and adaptive optimizations—making it an attractive execution platform. However, the garbage collector, the just‐in‐time compiler, and other optimizations and heuristics were designed primarily with the performance of Java programs in mind. Consequently, many of the languages targeting the JVM, and especially the dynamically typed languages, are suffering from performance problems that cannot be simply solved at the JVM side. In this article, we aim to contribute to the understanding of the character of the workloads imposed on the JVM by both dynamically typed and statically typed JVM languages. To this end, we introduce a new set of dynamic metrics for workload characterization, along with an easy‐to‐use toolchain to collect the metrics. We apply the toolchain to applications written in six JVM languages (Java, Scala, Clojure, Jython, JRuby, and JavaScript) and discuss the findings. Given the recently identified importance of inlining for the performance of Scala programs, we also analyze the inlining behavior of the HotSpot JVM when executing bytecode originating from different JVM languages. As a result, we identify several traits in the non‐Java workloads that represent potential opportunities for optimization. © 2015 The Authors. Software: Practice and Experience Published by John Wiley & Sons Ltd. 相似文献
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Monuko du Plessis Herzl Aharoni Lukas W. Snyman 《Sensors and actuators. A, Physical》2000,80(3):242-248
A novel multi-terminal silicon light emitting device (TRANSLED) is described where both the light intensity and spatial light pattern of the device are controlled by an insulated MOS gate voltage. This presents a major advantage over two terminals Si-LEDs, which require direct modulation of the relatively high avalanche current. It is found that, depending on the bias conditions, the light intensity is either a linear or a quadratic function of the applied gate voltage. The nonlinear relationship facilitates new applications such as the mixing of electrical input signals and modulating the optical output signal, which cannot readily be achieved with two terminal Si-LEDs, since they exhibit a linear relationship between diode avalanche current and light intensity. Furthermore, the control gate voltage can also modulate the emission pattern of the light emitting regions, for example, changing the TRANSLED from an optical line source to two point sources. 相似文献
16.
Lukas Martin Patrick Koczera Nadine Simons Elisabeth Zechendorf Janine Hoeger Gernot Marx Tobias Schuerholz 《International journal of molecular sciences》2016,17(3)
Sepsis is the most common cause of death in intensive care units and associated with widespread activation of host innate immunity responses. Ribonucleases (RNases) are important components of the innate immune system, however the role of RNases in sepsis has not been investigated. We evaluated serum levels of RNase 1, 3 and 7 in 20 surgical sepsis patients (Sepsis), nine surgical patients (Surgery) and 10 healthy controls (Healthy). RNase 1 and 3 were elevated in Sepsis compared to Surgery (2.2- and 3.1-fold, respectively; both p < 0.0001) or compared to Healthy (3.0- and 15.5-fold, respectively; both p < 0.0001). RNase 1 showed a high predictive value for the development of more than two organ failures (AUC 0.82, p = 0.01). Patients with renal dysfunction revealed higher RNase 1 levels than without renal dysfunction (p = 0.03). RNase 1 and 3 were higher in respiratory failure than without respiratory failure (p < 0.0001 and p = 0.02, respectively). RNase 7 was not detected in Healthy patients and only in two patients of Surgery, however RNase 7 was detected in 10 of 20 Sepsis patients. RNase 7 was higher in renal or metabolic failure than without failure (p = 0.04 and p = 0.02, respectively). In conclusion, RNase 1, 3 and 7 are secreted into serum under conditions with tissue injury, such as major surgery or sepsis. Thus, RNases might serve as laboratory parameters to diagnose and monitor organ failure in sepsis. 相似文献
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Arne Fallisch Leon Schellhase Jan Fresko Martin Zechmeister Mario Zedda Jens Ohlmann Lukas Zielke Nils Paust Tom Smolinka 《International Journal of Hydrogen Energy》2017,42(19):13544-13553
Hydrogen as a secondary energy carrier promises a large potential as a long term storage for fluctuating renewable energies. In this sense a highly efficient solar hydrogen generation is of great interest especially in southern countries having high solar irradiation. The patented Hydrogen Concentrator (HyCon) concept yields high efficiencies combining multi-junction solar cells with proton exchange (PEM) membrane water electrolysis. In this work, a special PEM electrolysis cell for the HyCon concept was developed and investigated. It is shown that the purpose-made PEM cell shows a high performance using a titanium hybrid fiber sinter function both as a porous transport layer and flow field. The electrolysis cell shows a high performance with 1.83 V at 1 A/cm2 and 24 °C working under natural convection with a commercially available catalyst coated membrane. A theoretical examination predicts a total efficiency for the HyCon module from sunlight to hydrogen of approximately 19.5% according to the higher heating value. 相似文献
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Magnetic Resonance Materials in Physics, Biology and Medicine - This work investigates electrodynamic constraints, explores RF antenna concepts and examines the transmission fields (B 1 + ) and RF... 相似文献