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991.
Applied Intelligence - In recent years, person re-identification (re-ID) has become a widespread research topic that focuses on retrieving target pedestrians from a set of images, typically taken... 相似文献
992.
Wang Bilin Wang Shengsheng Zhang Zhe Zhao Xin Fu Zihao 《Applied Intelligence》2022,52(12):14070-14084
Applied Intelligence - Unsupervised Domain Adaptation (UDA) aims to transfer knowledge from a label-rich source domain to an unlabeled target domain with a different but related distribution.... 相似文献
993.
Tungsten wires and porous NiAl prepared through directional solidification and selective dissolution
Zhilong Zhao Jianjun Gao Lufeng Wei Kai Chui 《Materials and Manufacturing Processes》2017,32(16):1817-1822
The combination of directional solidification and selective dissolution was applied to fabricate tungsten (W) wires and porous NiAl matrix. A NiAl–W pseudobinary eutectic alloy with 1.5?at.% tungsten was directionally solidified in a Bridgman-type oven at 1700°C. Results confirmed that the relationships of the growth rate with the interfibrous spacing and diameter of W fibrous phases in the directionally solidified samples are in accordance with the Jackson and Hunt (J?H) model. Afterward, the NiAl matrix was selectively dissolved in an HCl:H2O2 solution to reveal W wires, which present various three-dimensional (3D) morphologies at different growth rates. The W fibrous phases in the NiAl–W alloy samples were then selectively removed with a mixed etchant of ammonium acetate to form a porous NiAl matrix at a constant potential. Dynamic corrosion curves revealed that etching W from the NiAl matrix was inhibited after 2–3?h. The porous structures of NiAl after removing W phases are linked to the 3D morphologies of W fibrous phases embedded in the NiAl matrix. The aspect ratio of W wires and the structures of porous NiAl can be adjusted by selecting the process parameters of this combined technology. 相似文献
994.
Shiwei?Zhao T.?Matthew?EvansEmail authorView authors OrcID profile Xiaowen?Zhou Shuai?Zhou 《Granular Matter》2017,19(1):11
Temperature change, as a common kind of internal perturbation performed on granular materials, has a significant effect on the bulk properties of granular materials. However, few studies on thermally-induced shakedown under a long-term thermal cycling were reported. In this work, the discrete element method was used to give insight into the thermally-induced shakedown on the fabric and stress states within non-cohesive, frictional granular assemblies. Assemblies were submitted to thermal cycling at a stationary boundary condition after experiencing a one-dimensional compression. Evolution of coordination number, entropy and anisotropy was investigated as well as boundary forces and contact forces. At the same time, effects of the heating rate, the initial vertical load and the magnitude of temperature change were examined. It demonstrates that thermal cycling induces a significant force relaxation within granular materials, while the corresponding granular fabric has a small change. In addition, the entropy and anisotropy decreases with thermal cycling. Moreover, the initial vertical load can constrain the development of thermally-induced fabric change, thereby limiting force relaxation to some degree. Both high heating rate and larger magnitudes of temperature change contribute to more significant force relaxation. However, they cause smaller fabric changes even though they provide larger perturbations. 相似文献
995.
996.
Construction of Asymmetrical Hexameric Biomimetic Motors with Continuous Single‐Directional Motion by Sequential Coordination 下载免费PDF全文
Zhengyi Zhao Hui Zhang Dan Shu Carlo Montemagno Baoquan Ding Jingyuan Li Peixuan Guo 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(1)
The significance of bionanomotors in nanotechnology is analogous to mechanical motors in daily life. Here the principle and approach for designing and constructing biomimetic nanomotors with continuous single‐directional motion are reported. This bionanomotor is composed of a dodecameric protein channel, a six‐pRNA ring, and an ATPase hexamer. Based on recent elucidations of the one‐way revolving mechanisms of the phi29 double‐stranded DNA (dsDNA) motor, various RNA and protein elements are designed and tested by single‐molecule imaging and biochemical assays, with which the motor with active components has been constructed. The motor motion direction is controlled by three operation elements: (1) Asymmetrical ATPase with ATP‐interacting domains for alternative DNA binding/pushing regulated by an arginine finger in a sequential action manner. The arginine finger bridges two adjacent ATPase subunits into a non‐covalent dimer, resulting in an asymmetrical hexameric complex containing one dimer and four monomers. (2) The dsDNA translocation channel as a one‐way valve. (3) The hexameric pRNA ring geared with left‐/right‐handed loops. Assessments of these constructs reveal that one inactive subunit of pRNA/ATPase is sufficient to completely block motor function (defined as K = 1), implying that these components work sequentially based on the principle of binomial distribution and Yang Hui's triangle. 相似文献
997.
Reducing Hysteresis and Enhancing Performance of Perovskite Solar Cells Using Low‐Temperature Processed Y‐Doped SnO2 Nanosheets as Electron Selective Layers 下载免费PDF全文
Guang Yang Hongwei Lei Hong Tao Xiaolu Zheng Junjie Ma Qin Liu Weijun Ke Zhiliang Chen Liangbin Xiong Pingli Qin Zhao Chen Minchao Qin Xinhui Lu Yanfa Yan Guojia Fang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(2)
Despite the rapid increase of efficiency, perovskite solar cells (PSCs) still face some challenges, one of which is the current–voltage hysteresis. Herein, it is reported that yttrium‐doped tin dioxide (Y‐SnO2) electron selective layer (ESL) synthesized by an in situ hydrothermal growth process at 95 °C can significantly reduce the hysteresis and improve the performance of PSCs. Comparison studies reveal two main effects of Y doping of SnO2 ESLs: (1) it promotes the formation of well‐aligned and more homogeneous distribution of SnO2 nanosheet arrays (NSAs), which allows better perovskite infiltration, better contacts of perovskite with SnO2 nanosheets, and improves electron transfer from perovskite to ESL; (2) it enlarges the band gap and upshifts the band energy levels, resulting in better energy level alignment with perovskite and reduced charge recombination at NSA/perovskite interfaces. As a result, PSCs using Y‐SnO2 NSA ESLs exhibit much less hysteresis and better performance compared with the cells using pristine SnO2 NSA ESLs. The champion cell using Y‐SnO2 NSA ESL achieves a photovoltaic conversion efficiency of 17.29% (16.97%) when measured under reverse (forward) voltage scanning and a steady‐state efficiency of 16.25%. The results suggest that low‐temperature hydrothermal‐synthesized Y‐SnO2 NSA is a promising ESL for fabricating efficient and hysteresis‐less PSC. 相似文献
998.
999.
In Situ Observation of Crystallization of Methylammonium Lead Iodide Perovskite from Microdroplets 下载免费PDF全文
Yahui Li Zhenhao Zhao Feng Lin Xiaobing Cao Xian Cui Jinquan Wei 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(26)
It is of great importance to investigate the crystallization of organometallic perovskite from solution for enhancing performance of perovskite solar cells. Here, this study develops a facile method for in situ observation of crystallization and growth of the methylammonium lead iodide (MAPbI3) perovskite from microdroplets ejected by an alternating viscous and inertial force jetting method. It is found that there are two crystallization modes when MAPbI3 grows from the CH3NH3I (MAI)/PbI2/N,N‐dimethylformamide (DMF) solution: needle precursors and granular perovskites. Generally, needle Lewis adduct of MAPbI3·DMF tends to nucleate and grow from the solution due to low solubility of PbI2. The growth of MAPbI3·DMF depends on both the concentration of MAI and temperature. It tends to form large perovskite domains on substrates at high temperature. The MAPbI3·DMF coverts to nanocrystalline perovskite due to lattice shrinkage when DMF molecules escape from the Lewis adduct. Granular perovskite can also directly nucleate from the solution at high concentration of MAI due to compositional segregation. 相似文献
1000.
Hua Yu Zhengzhong Yang Luojun Du Jing Zhang Jinan Shi Wei Chen Peng Chen Mengzhou Liao Jing Zhao Jianling Meng Guole Wang Jianqi Zhu Rong Yang Dongxia Shi Lin Gu Guangyu Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(7)
Control of the precise lattice alignment of monolayer molybdenum disulfide (MoS2) on hexagonal boron nitride (h‐BN) is important for both fundamental and applied studies of this heterostructure but remains elusive. The growth of precisely aligned MoS2 domains on the basal plane of h‐BN by a low‐pressure chemical vapor deposition technique is reported. Only relative rotation angles of 0° or 60° between MoS2 and h‐BN basal plane are present. Domains with same orientation stitch and form single‐crystal, domains with different orientations stitch and from mirror grain boundaries. In this way, the grain boundary is minimized and a continuous film stitched by these two types of domains with only mirror grain boundaries is obtained. This growth strategy is also applicable to other 2D materials growth. 相似文献