23,086 research outputs found
Pure donation or hybrid donation crowdfunding : Which model is more conducive to prosocial campaign success?
Author's accepted manuscript (postprint).acceptedVersio
Chinese reverse M&As in the Netherlands : Chinese managers’ trust building practices
Author's accepted manuscript (postprint).acceptedVersio
Outbreak of Soybean Aphid in Suihua District in 1998 and its Control Strategies
In 1998, the soybean aphid Aphis glycines Matsumura severely infested soybeans in previously unfested areas and unprecedented damage levels in Suihua District. Damage by soybean aphids caused huge losses. Yield losses in the district were up to 30% on average with a yield reduction of 112.5 million kilograms. The development characteristics, cause and control strategies of soybean aphids in 1998 are presented as follows.Originating text in Chinese.Citation: Sun, Bo, Liang, Shubao, Zhao, Weixia. (2000). Outbreak of Soybean Aphid in Suihua District in 1998 and its Control Strategies. Soybean Bulletin, 8(1), 5-5
Testing, numerical modelling and design of S690 high strength steel welded I-section stub columns
This paper describes a comprehensive testing and numerical simulation investigation into the material properties, membrane residual stresses and compression capacities of S690 high strength steel welded I-section stub columns. The testing programme was performed on eight welded I-sections fabricated from 5 mm thick S700MC high strength steel hot-rolled plates by means of gas metal arc welding, and included material tensile coupon tests, membrane residual stress measurements, initial local geometric imperfection measurements, and sixteen concentrically loaded stub column tests. A membrane residual stress distribution model for S690 high strength steel welded I-sections was firstly proposed, based on the experimentally measured results. In conjunction with the structural testing, a numerical modelling study was carried out, in which finite element models were initially developed and validated against the experimental results, and afterwards employed to conduct parametric studies, aiming at generating further structural performance data over a broader range of cross-section sizes. The obtained experimental and numerical data were used to evaluate the accuracy of the slenderness limits (for classifications of plate elements and cross-sections) and design rules for S690 high strength steel welded I-section stub columns, as set out in the European, American and Australian standards. The results of the evaluation revealed that the codified slenderness limits are accurate for the plate element and cross-section classifications of S690 welded I-sections in compression, and the established local buckling design provisions in the considered three codes result in precise and consistent cross-section compression resistance predictions for both non-slender and slender S690 welded I-section stub columns
Motion-aware Memory Network for Fast Video Salient Object Detection
Previous methods based on 3DCNN, convLSTM, or optical flow have achieved
great success in video salient object detection (VSOD). However, they still
suffer from high computational costs or poor quality of the generated saliency
maps. To solve these problems, we design a space-time memory (STM)-based
network, which extracts useful temporal information of the current frame from
adjacent frames as the temporal branch of VSOD. Furthermore, previous methods
only considered single-frame prediction without temporal association. As a
result, the model may not focus on the temporal information sufficiently. Thus,
we initially introduce object motion prediction between inter-frame into VSOD.
Our model follows standard encoder--decoder architecture. In the encoding
stage, we generate high-level temporal features by using high-level features
from the current and its adjacent frames. This approach is more efficient than
the optical flow-based methods. In the decoding stage, we propose an effective
fusion strategy for spatial and temporal branches. The semantic information of
the high-level features is used to fuse the object details in the low-level
features, and then the spatiotemporal features are obtained step by step to
reconstruct the saliency maps. Moreover, inspired by the boundary supervision
commonly used in image salient object detection (ISOD), we design a
motion-aware loss for predicting object boundary motion and simultaneously
perform multitask learning for VSOD and object motion prediction, which can
further facilitate the model to extract spatiotemporal features accurately and
maintain the object integrity. Extensive experiments on several datasets
demonstrated the effectiveness of our method and can achieve state-of-the-art
metrics on some datasets. The proposed model does not require optical flow or
other preprocessing, and can reach a speed of nearly 100 FPS during inference.Comment: 12 pages, 10 figure
Biphenyl-bridged 6-(1-aryliminoethyl)-2-iminopyridyl-cobalt complexes: synthesis, characterization and ethylene polymerization behavior
A series of biphenyl-bridged 6-(1-aryliminoethyl)-2-iminopyridine derivatives reacted with cobalt dichloride in dichloromethane/ethanol to afford the corresponding binuclear cobalt complexes. The cobalt complexes were characterized by FT-IR spectroscopy and elemental analysis, and the structure of a representative complex was confirmed by single-crystal X-ray diffraction. Upon activation with either MAO or MMAO, these cobalt complexes performed with high activities of up to 1.2 × 10⁷ g (mol of Co)⁻¹ h⁻¹ in ethylene polymerization, which represents one of the most active cobalt-based catalytic systems in ethylene reactivity. These biphenyl-bridged bis(imino)pyridylcobalt precatalysts exhibited higher activities than did their mononuclear bis(imino)pyridylcobalt precatalyst counterparts, and more importantly, the binuclear precatalysts revealed a better thermal stability and longer lifetimes. The polyethylenes obtained were characterized by GPC, DSC, and high-temperature NMR spectroscopy and mostly possessed unimodal and highly linear features
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