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排序方式： 共有2673条查询结果，搜索用时 15 毫秒
71.
Shuo Li Erik van der Horst Philipp Duernay Christophe De Wagter Guido C. H. E. de Croon 《野外机器人技术杂志》2020,37(4):667-692
Drone racing is becoming a popular e‐sport all over the world, and beating the best human drone race pilots has quickly become a new major challenge for artificial intelligence and robotics. In this paper, we propose a novel sensor fusion method called visual model‐predictive localization (VML). Within a small time window, VML approximates the error between the model prediction position and the visual measurements as a linear function. Once the parameters of the function are estimated by the RANSAC algorithm, this error model can be used to compensate the prediction in the future. In this way, outliers can be handled efficiently and the vision delay can also be compensated efficiently. Theoretical analysis and simulation results show the clear advantage compared with Kalman filtering when dealing with the occasional large outliers and vision delays that occur in fast drone racing. Flight tests are performed on a tiny racing quadrotor named “Trashcan,” which was equipped with a Jevois smart camera for a total of 72 g. An average speed of 2 m/s is achieved while the maximum speed is 2.6 m/s. To the best of our knowledge, this flying platform is currently the smallest autonomous racing drone in the world, while still being one of the fastest autonomous racing drones. 相似文献
72.
Anna Musia&#x; Kinga o&#x;nacz Nicole Srocka Oleh Kravets Jan Große Jacek Olszewski Krzysztof Poturaj Grzegorz Wjcik Pawe&#x; Mergo Kamil Dybka Mariusz Dyrkacz Micha&#x; D&#x;ubek Kristian Lauritsen Andreas Bülter Philipp‐Immanuel Schneider Lin Zschiedrich Sven Burger Sven Rodt Wac&#x;aw Urba&#x;czyk Grzegorz S&#x;k Stephan Reitzenstein 《Advanced Quantum Technologies》2020,3(6)
A user‐friendly, fiber‐coupled, single‐photon source operating at telecom wavelengths is a key component of photonic quantum networks providing long‐haul, ultra‐secure data exchange. To take full advantage of quantum‐mechanical data protection and to maximize the transmission rate and distance, a true quantum source providing single photons on demand is highly desirable. This great challenge is tackled by developing a ready‐to‐use semiconductor quantum‐dot‐based device that launches single photons at a wavelength of 1.3 µm directly into a single‐mode optical fiber. In the proposed approach, the quantum dot is deterministically integrated into a nanophotonic structure to ensure efficient on‐chip coupling into a fiber. The whole arrangement is integrated into a 19ʺ compatible housing to enable stand‐alone operation by cooling via a compact Stirling cryocooler. The realized source delivers single photons with a multiphoton events probability as low as 0.15 and a single‐photon emission rate of up to 73 kHz into a standard telecom single‐mode fiber. 相似文献
73.
Pinak Samal Philipp Maurer Clemens van Blitterswijk Roman Truckenmüller Stefan Giselbrecht 《Advanced materials (Deerfield Beach, Fla.)》2020,32(24):1907966
Recently developed stem-cell-based in vitro models of morphogenesis can help shed light on the mechanisms involved in embryonic patterning. These models are showcased using traditional cell culture platforms and materials, which allow limited control over the biological system and usually do not support high-content imaging. In contrast, using advanced microengineered tools can help in microscale control, long-term culture, and real-time data acquisition from such biological models and aid in elucidating the underlying mechanisms. Here, a new culturing, manipulation and analysis platform is described to study in vitro morphogenesis using thin polycarbonate film-based microdevices. A pipeline consisting of open-source software to quantify 3D cell movement using 4D image acquisition is developed to analyze cell migration within the multicellular clusters. It is shown that the platform can be used to control and study morphogenesis in non-adherent cultures of the P19C5 mouse stem cell line and mouse embryonic stem cells (mESCs) that show symmetry breaking and axial elongation events similar to early embryonic development. Using the new platform, it is found that localized cell proliferation and coordinated cell migration result in elongation morphogenesis of the P19C5 aggregates. Further, it is found that polarization and elongation of mESC aggregates are dependent on directed cell migration. 相似文献
74.
Philipp Jordt Niklas Wolff Stjepan B. Hrkac Sindu Shree Di Wang Ross J. Harder Christian Kübel Rainer Adelung Oleg G. Shpyrko Olaf M. Magnussen Lorenz Kienle Bridget M. Murphy 《Advanced Electronic Materials》2021,7(11):2100546
Novel devices ranging from bio magnetic field sensors to energy harvesting nano machines utilize the piezotronic effect. For optimal function, understanding the interaction of electrical and strain phenomena within the semiconductor crystal is necessary. Here, studies of a model piezotronic system are presented, consisting of a ZnO microrod coated by a thin layer of gold, which forms a Schottky contact with the piezoelectric ZnO material. Coherent X-ray diffraction imaging (CXDI) and transmission electron microscopy (TEM) are used to visualize the structure and strain distribution, showing that the ZnO microrod exhibits strains of multiple origins in the bulk and at the interface. Strain values of −6 × 10-4 have been measured by CXDI at the ZnO/Au interface. The origin is shown to be a combination of an interface strain, possibly caused by the Schottky contact formation, and distinct, localized electrical fields inside the crystal which are assigned to electron depletion and screening in a bent ZnO/Au piezotronic rod. These findings will contribute to sensor development and to a better understanding of piezotronic applications. 相似文献
75.
We have developed a self-consistent quantum mechanical Monte Carlo device simulator that takes electron transport in quantized states into consideration. Two-dimensional quantized states in MOSFET channels are constructed from one-dimensional solutions of the Schrödinger equation at different positions along the channel, and the Schrödinger and Poisson equations are solved self-consistently in terms of electron concentration and electrostatic potential distribution. The channel electron concentration, velocity and drain currents are calculated with the one particle Monte Carlo approach incorporating the intra-valley acoustic phonon and inter-valley phonon scattering mechanisms. This simulator was applied to a 70 nm n-MOSFET transistor, and we found that current mostly flows through the lowest subband and transport is quasi-ballistic near the source junction. To quantitatively estimate the performance of advanced devices, we have developed an inversion carrier transport simulator based on a full-band model. Our simulation method enables us to evaluate device characteristics and analyze the transport properties of ultra-small MOSFETs. 相似文献
76.
We report on the development of an algorithm to improve the registration of serial 3D MR breast images using combined global
translation and rotation with locally varying parameters as geometric transformations. Several phantom and volunteer data
sets were acquired and registered using mutual information as a similarity measure of the matching process. After applying
a global translation by using a rigid matcher, optimum horizontal and vertical rotation angles were determined. In case of
the phantom measurements, angle optimization was performed for each slice of the 3D data set of the phantom, which was deliberately
shifted and rotated around different axes. In case of registration of volunteer data, optimum rotation parameters were calculated
for preselected equidistant slices of the data set to speed up the calculation time. For slices located between and outside
these support slices, the rotation angles were calculated by linear interpolation and extrapolation of the slope of the regression
determined by the optimized angles of the support slices. The algorithm improves the registration of serial 3D MR data sets
and represents a compromise between a rigid and an elastic 3D matching procedure. 相似文献
77.
78.
Manuel Grander Alexander Hoffmann Markus Seifert Egon Demetz Philipp Grubwieser Christa Pfeifhofer-Obermair David Haschka Günter Weiss 《International journal of molecular sciences》2022,23(12)
Macrophages are at the center of innate pathogen control and iron recycling. Divalent metal transporter 1 (DMT1) is essential for the uptake of non-transferrin-bound iron (NTBI) into macrophages and for the transfer of transferrin-bound iron from the endosome to the cytoplasm. As the control of cellular iron trafficking is central for the control of infection with siderophilic pathogens such as Salmonella Typhimurium, a Gram-negative bacterium residing within the phagosome of macrophages, we examined the potential role of DMT1 for infection control. Bone marrow derived macrophages lacking DMT1 (DMT1fl/flLysMCre(+)) present with reduced NTBI uptake and reduced levels of the iron storage protein ferritin, the iron exporter ferroportin and, surprisingly, of the iron uptake protein transferrin receptor. Further, DMT1-deficient macrophages have an impaired control of Salmonella Typhimurium infection, paralleled by reduced levels of the peptide lipocalin-2 (LCN2). LCN2 exerts anti-bacterial activity upon binding of microbial siderophores but also facilitates systemic and cellular hypoferremia. Remarkably, nifedipine, a pharmacological DMT1 activator, stimulates LCN2 expression in RAW264.7 macrophages, confirming its DMT1-dependent regulation. In addition, the absence of DMT1 increases the availability of iron for Salmonella upon infection and leads to increased bacterial proliferation and persistence within macrophages. Accordingly, mice harboring a macrophage-selective DMT1 disruption demonstrate reduced survival following Salmonella infection. This study highlights the importance of DMT1 in nutritional immunity and the significance of iron delivery for the control of infection with siderophilic bacteria. 相似文献
79.
Chiara Fischer Andrey Turchinovich Manuel Feisst Fabian Riedel Kathrin Haßdenteufel Philipp Scharli Andreas D. Hartkopf Sara Y. Brucker Laura Michel Barbara Burwinkel Andreas Schneeweiss Markus Wallwiener Thomas M. Deutsch 《International journal of molecular sciences》2022,23(17)
The extracellular circulating microRNA (miR)-200 regulates epithelial-mesenchymal transition and, thus, plays an essential role in the metastatic cascade and has shown itself to be a promising prognostic and predictive biomarker in metastatic breast cancer (MBC). Expression levels of the plasma miR-200 family were analyzed in relationship to systemic treatment, circulating tumor cells (CTC) count, progression-free survival (PFS), and overall survival (OS). Expression of miR-200a, miR-200b, miR-200c, miR-141, and miR-429, and CTC status (CTC-positive ≥ 5 CTC/7.5 mL) was assessed in 47 patients at baseline (BL), after the first completed cycle of a new line of systemic therapy (1C), and upon the progression of disease (PD). MiR-200a, miR-200b, and miR-141 expression was reduced at 1C compared to BL. Upon PD, all miR-200s were upregulated compared to 1C. At all timepoints, the levels of miR-200s were elevated in CTC-positive versus CTC-negative patients. Further, heightened miR-200s expression and positive CTC status were associated with poorer OS at BL and 1C. In MBC patients, circulating miR-200 family members decreased after one cycle of a new line of systemic therapy, were elevated during PD, and were indicative of CTC status. Notably, increased levels of miR-200s and elevated CTC count correlated with poorer OS and PFS. As such, both are promising biomarkers for optimizing the clinical management of MBC. 相似文献
80.
Philipp Kasper Jaco Selle Christina Vohlen Rebecca Wilke Celien Kuiper-Makris Oleksiy Klymenko Inga Bae-Gartz Charlotte Schmig Alexander Quaas Bjrn Schumacher Münevver Demir Martin Bürger Sonja Lang Anna Martin Hans-Michael Steffen Tobias Goeser Jrg Dtsch Miguel A. Alejandre Alcazar 《International journal of molecular sciences》2022,23(10)
Maternal obesity predisposes for hepato-metabolic disorders early in life. However, the underlying mechanisms causing early onset dysfunction of the liver and metabolism remain elusive. Since obesity is associated with subacute chronic inflammation and accelerated aging, we test the hypothesis whether maternal obesity induces aging processes in the developing liver and determines thereby hepatic growth. To this end, maternal obesity was induced with high-fat diet (HFD) in C57BL/6N mice and male offspring were studied at the end of the lactation [postnatal day 21 (P21)]. Maternal obesity induced an obese body composition with metabolic inflammation and a marked hepatic growth restriction in the male offspring at P21. Proteomic and molecular analyses revealed three interrelated mechanisms that might account for the impaired hepatic growth pattern, indicating prematurely induced aging processes: (1) Increased DNA damage response (γH2AX), (2) significant upregulation of hepatocellular senescence markers (Cdnk1a, Cdkn2a); and (3) inhibition of hepatic insulin/insulin-like growth factor (IGF)-1-AKT-p38-FoxO1 signaling with an insufficient proliferative growth response. In conclusion, our murine data demonstrate that perinatal obesity induces an obese body composition in male offspring with hepatic growth restriction through a possible premature hepatic aging that is indicated by a pathologic sequence of inflammation, DNA damage, senescence, and signs of a possibly insufficient regenerative capacity. 相似文献