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排序方式: 共有992条查询结果,搜索用时 31 毫秒
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科学评价大学生科研创新能力对我国科研水平的提高具有重要意义.采用机器学习模型来预测大学生科研能力可以起到良好的效果,提出一种GAXGBoost模型来实现对大学生的科研能力预测.此模型是以Xgboost算法为基础,然后充分利用遗传算法的全局搜索能力自动搜索Xgboost最优超参数,避免了人为经验调参不准确的缺陷,最后采用精英选择策略以此确保每一轮都是最佳的进化结果.通过分析表明,所采用的GAXGBoost模型在大学生科研能力预测的结果中具有很高的精度,将此模型与Logistic Regression、Random Forest、SVM等模型进行对比,GAXGBoost模型的预测精度最高. 相似文献
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Cao Hongmei Deng Shenzhen Tie Zhiwei Tian Jinlei Liu Lili Niu Zhiqiang 《中国科学:化学(英文版)》2022,65(9):1725-1732
Science China Chemistry - Synchronously reducing/self-assembling strategy on Zn substrate was designed to fabricate large-area cation-doped hydrated V2O5/multi-walled carbon nanotube (D-HVO/MWCNT)... 相似文献
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《中国化学快报》2020,31(6):1516-1519
CuWO_4,as an n-type oxide semiconductor with a bandgap of 2.2 eV,has stimulated enormous interest as a potential broad-spectrum-active photocatalyst for environmental pollution remediations.However,rapid charge recombination greatly hinders its practical applications.Herein,we present a cascaded electron transition pathway in a ternary heterostructure consisting of CdS quantum dots,carbon dots(CDs) and CuWO_4 hollow spheres,which proves to greatly facilitate the photogenerated electron-hole separation,and eventually boosts the degradation efficiency of phenol and congo red by 100% and 46%compared to bare CuWO_4.The enhanced performance of the CuWO_4/CdS/CDs heterostructure mainly originates from the unidirectional electron migration from CdS to CuWO_4 and then to the organics through CDs.This work elucidates the electron transfer kinetics in multi-phase system and provides a new design paradigm for optimizing the properties of CuWO_4 based photocatalysts. 相似文献
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Dr. Ying Wang Dr. Wenming Sun Xiaofei Ling Xiangkai Shi Dr. Lanlan Li Prof. Yida Deng Dr. Cuihua An Dr. Xiaopeng Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(18):4097-4103
The development of high-efficiency, low-cost, and earth-abundant electrocatalysts for overall water splitting remains a challenge. In this work, Ni-modified MoS2 hybrid catalysts are grown on carbon cloth (Ni-Mo-S@CC) through a one-step hydrothermal treatment. The optimized Ni-Mo-S@CC catalyst shows excellent hydrogen evolution reaction (HER) activity with a low overpotential of 168 mV at a current density of 10 mA cm−2 in 1.0 m KOH, which is lower than those of Ni-Mo-S@CC (1:1), Ni-Mo-S@CC (3:1), and pure MoS2. Significantly, the Ni-Mo-S@CC hybrid catalyst also displays outstanding oxygen evolution reaction (OER) activity with a low overpotential of 320 mV at a current density of 10 mA cm−2, and remarkable long-term stability for 30 h at a constant current density of 10 mA cm−2. Experimental results and theoretical analysis based on density functional theory demonstrate that the excellent electrocatalytic performance can be attributed mainly to the remarkable conductivity, abundant active sites, and synergistic effect of the Ni-doped MoS2. This work sheds light on a unique strategy for the design of high-performance and stable electrocatalysts for water-splitting electrolyzers. 相似文献