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排序方式: 共有597条查询结果,搜索用时 15 毫秒
591.
Robert Arendt Christian Reinhardt-Imjela Leona Faulstich Achim Schulte André Assmann Robert Jüpner Petrina T. Johannes Damas Alfred Mashauri 《河流研究与利用》2023,39(9):1902-1918
The transboundary region of the Iishana system in the western Cuvelai Basin, between southern Angola and northern Namibia, is frequently affected by floods at irregular intervals. As a result, the predominantly rural, subsistence farming population has experienced crop failures, human, and economic losses. To date, very little is known about the generation of floods, flood concentration, and stormwater drainage dynamics in this region. In this study, 2D-hydrodynamic modeling was applied to reconstruct one of the latest major flood events during the rainy season from November 2008 to March 2009 in order to study the runoff behavior and interconnectivity of the Iishana system. The model focused on the eastern part of the Iishana system, which was most affected by floods and flood damage due to the high population density in and around Oshakati, the regional capital. Two main streams were identified noteworthy because they merge and subsequently affect Oshakati. Regarding the simulated flood event water depths vary from 0.1 m to 14 m, with an average of 0.2 m, while water depths above 5 m were attributed to borrow pits. The inundation area ranged up to 1860 km2 and the amount of water left after the rainy season on March 25th, 2009, was determined between 0.116 and 0.547 km3, depending on the amount of evapotranspiration considered in the model. Thus, in the Angolan part of the Iishana system, significantly larger quantities of water are available for longer periods of time during the subsequent dry season, whereas the system in Namibia stores less water, resulting in a shorter water retention period. 相似文献
592.
Achim Mehlhorn Jürgen Fabian Nikolay Tyutyulkov Gottfried Olbrich Fritz Dietz 《Advanced Synthesis \u0026amp; Catalysis》1986,328(4):603-611
Ab initio SCF and semiempirical MINDO/3 and PPP/DCI calculations have been applied to substituted cyclopentamethines which formally resulted from cyclization of streptopentamethines in the α,α′-positions. These compounds exhibit a typical streptopolymethinic charge distribution of the carbon atoms along the cyclized chain, unique molecular geometries, extremely small energy gaps between the lowest excited states S1, T1 and the ground state S0 as well as large electron affinities. With respect to molecular geometry, spectral behaviour and electron affinity substituted cyclopentamethines are closely related to the antiaromatic cyclopentadienyl cation. Depending on the substitution pattern, the one or the other of the two Jahn-Teller distorted geometries of the antiaromatic C5H5⊕ appears to be frozen. 相似文献
593.
Horst H. Krause Norbert Eisenreich Achim Pfeil 《Propellants, Explosives, Pyrotechnics》1992,17(4):179-181
RDX products obtained at high heating rates are discussed. RDX was decomposed by combustion in pressurized bomb and by short laser pulse irradiation. 相似文献
594.
Registration of point cloud data containing both depth and color information is critical for a variety of applications, including in-field robotic plant manipulation, crop growth modeling, and autonomous navigation. However, current state-of-the-art registration methods often fail in challenging agricultural field conditions due to factors such as occlusions, plant density, and variable illumination. To address these issues, we propose the NDT-6D registration method, which is a color-based variation of the Normal Distribution Transform (NDT) registration approach for point clouds. Our method computes correspondences between pointclouds using both geometric and color information and minimizes the distance between these correspondences using only the three-dimensional (3D) geometric dimensions. We evaluate the method using the GRAPES3D data set collected with a commercial-grade RGB-D sensor mounted on a mobile platform in a vineyard. Results show that registration methods that only rely on depth information fail to provide quality registration for the tested data set. The proposed color-based variation outperforms state-of-the-art methods with a root mean square error (RMSE) of 1.1–1.6 cm for NDT-6D compared with 1.1–2.3 cm for other color-information-based methods and 1.2–13.7 cm for noncolor-information-based methods. The proposed method is shown to be robust against noises using the TUM RGBD data set by artificially adding noise present in an outdoor scenario. The relative pose error (RPE) increased 14% for our method compared to an increase of 75% for the best-performing registration method. The obtained average accuracy suggests that the NDT-6D registration methods can be used for in-field precision agriculture applications, for example, crop detection, size-based maturity estimation, and growth modeling. 相似文献
595.
Peter Bächler Dr.-Ing. Jörg Meyer Prof. Dr.-Ing. habil. Achim Dittler 《化学,工程师,技术》2023,95(1-2):178-188
Conventional particle emission measurement technology only takes into account the total emission and does not offer spatial resolution. Extensive troubleshooting is required in order to identify potential emission hotspots (e.g., small leaks) that contribute strongly to dust emissions. A network of inexpensive low-cost PM-sensors was used in a small-scale baghouse filter for spatial online particle emission monitoring. Different types of emission hotspots were investigated. Spatial PM monitoring enabled the reliable identification of the position of the hotspot as well as estimation of leak size. 相似文献
596.
Linda Schäker-Hübner Reza Haschemi Dr. Thomas Büch Fabian B. Kraft Birke Brumme Andrea Schöler Dr. Robert Jenke Prof. Dr. Jens Meiler Prof. Dr. Achim Aigner Prof. Dr. Gerd Bendas Prof. Dr. Finn K. Hansen 《ChemMedChem》2022,17(9):e202100755
Herein we report the structure-activity and structure-physicochemical property relationships of a series of class I selective ortho-aminoanilides targeting the “foot-pocket” in HDAC1&2. To balance the structural benefits and the physicochemical disadvantages of these substances, we started with a set of HDACi related to tacedinaline (CI-994) and evaluated their solubility, lipophilicity (log D7.4) and inhibition of selected HDAC isoforms. Subsequently, we selected the most promising “capless” HDACi and transferred its ZBG to our previously published scaffold featuring a peptoid-based cap group. The resulting hit compound 10 c ( LSH-A54) showed favorable physicochemical properties and is a potent, selective HDAC1/2 inhibitor. The following evaluation of its slow binding properties revealed that LSH-A54 binds tightly to HDAC1 in an induced-fit mechanism. The potent HDAC1/2 inhibitory properties were reflected by attenuated cell migration in a modified wound healing assay and reduced cell viability in a clonogenic survival assay in selected breast cancer cell lines. 相似文献
597.
Achim Pfeil 《Propellants, Explosives, Pyrotechnics》1999,24(3):156-158
The microbial degradation of nitrocellulose investigated in a composting environment appeared not to be straightforward. Depending on the degree of esterification the large nitrate groups may sterically hinder the enzymatic hydrolysis or effectively block it. 相似文献