http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
왕덕현,이윤경,우정윤,허보영 한국공작기계학회 1998 한국생산제조학회지 Vol.7 No.1
Conductive metal matrix composite(MMC) material of 30% silicon carbide particulate based on aluminum matrix was machined by die sinking electrical discharge machining(EDM) process according to different current and duty factor for reverse polarity of electrode. Material removal rate(MRR) was examined by process under various operating conditions. The surface morphology was evaluated by surface roughness parameter and scanning electron microscopy(SEM) research. The MRR was suddenly increased over 11 ampere of current, and it was slightly changed over 0.3 of duty factor. The maximum surface roughness of EDMed surface was affected by the duty factor. The SEM photographs of EDMed surface showed wide recast distribution region of melting materials as increased of current and duty factor.
Wang, Bo,Xie, Ying,Liu, Tong,Luo, Hao,Wang, Bin,Wang, Chunhui,Wang, Lei,Wang, Dianlong,Dou, Shixue,Zhou, Yu Elsevier 2017 Nano energy Vol.42 No.-
<P><B>Abstract</B></P> <P>Due to the relatively slow, diffusion-controlled faradaic reaction mechanisms of conventional LiFePO<SUB>4</SUB> (LFP) materials, which is hard to deliver satisfied capacity for high rate applications. In this work, ultrafine LFP quantum dots (LFP-QDs) co-modified by two types of carbonaceous materials - amorphous carbon and graphitized conductive carbon (graphene) have been successfully synthesized through a novel microreactor strategy. Because of the very limited area constructed by the dual-carbon microreactor for the growth of LFP crystal, it's demension was furthest suppressed to a very small level (~ 6.5nm). Such a designed nano-composite possesses a large specific surface area for charge adsorption and abundant active sites for faradaic reactions, as well as ideal kinetic features for both electron and ion transport, and thus exhibits ultra-fast, surface-reaction-controlled lithium storage behavior, mimicking the pseudocapacitive mechanisms for supercapacitor materials, in terms of extraordinary rate capability (78mAhg<SUP>−1</SUP> at 200C) and remarkable cycling stability (~ 99% over 1000 cycles at 20C). On the other side, due to the quasi-2D structure of the synthesized LFP-QDs composite, which can be used as the basic unit to further fabricate free-standing film, aerogel and fiber electrode without the addition of binder and conductive agent for different practical applications. In addition, to deeper understand its electrochemical behavior, a combined experimental and density functional theoretical (DFT) calculation study is also introduced.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A general microreactor strategy has been developed for structure-optimized Li-contained electrode materials. </LI> <LI> Ultrafine LiFePO<SUB>4</SUB> quantum dots are first reported through the designed microreactor strategy. </LI> <LI> The synthesized G/LFP-QDs@C exhibits ultra-fast, surface-reaction-controlled Li storage behavior. </LI> <LI> A combined experimental and DFT calculation study is introduced to reveal the energy storage mechanism of G/LFP-QDs@C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Ultrafine LiFePO<SUB>4</SUB> quantum dots (~ 6.5nm) co-modified by two types of carbonaceous materials - amorphous carbon and graphitized conductive carbon (graphene) have been successfully synthesized through a novel microreactor strategy, which exhibit ultra-fast, surface-reaction-controlled energy storage behavior, mimicking the pseudocapacitive mechanisms for supercapacitor materials, in terms of excellent rate capability and outstanding cycling stability.</P> <P>[DISPLAY OMISSION]</P>
Bo Gao,Da Chen,Bingli Gu,Ting Wang,Zihao Wang,Feng xie,Yongsheng Yang,Qinglei Guo,Gang Wang 한국물리학회 2020 Current Applied Physics Vol.20 No.4
Nitrogen-doped graphene quantum dots (N-GQDs) with high blue fluorescence efficiency were synthesized by the hydrothermal method from p-Phenylenediamine and p-Coumaric acid. The N-GQDs possess several superiorities, most significantly in excellent solubility and superior photostability. Besides, the as-prepared N-GQDs exhibit a uniform size distribution with a diameter of about 3.8 ± 0.5 nm. After dispersing the N-GQDs in water, the formed aqueous solution still presents a stable and homogeneous phase even after 2 months at room temperature. The N-GQD dispersion was further utilized as sensing probes for the selective detection of copper ions (Cu2+), which is realized by the photoluminescence (PL) quenching of N-GQDs after adding Cu2+. The detection limit for Cu2+ was found to be 57 nM L−1, with superior selectivity in the presence of other commonly interfering metal ions. The presented results in this study provide a facile and high-efficiency method for synthesizing N-GQDs, with ultra-high detectivity and selectivity for Cu2+ detection, offering numerous opportunities for the development of biosensing, bioimaging, environment monitoring, and others.
EXISTENCE AND LARGE TIME BEHAVIOR OF SOLUTIONS TO A FOURTH-ORDER DEGENERATE PARABOLIC EQUATION
Bo Liang,Meishan Wang,Ying Wang 대한수학회 2015 대한수학회보 Vol.52 No.4
The paper is devoted to studying a fourth-order degenerate parabolic equation, which arises in fluid, phase transformation and biology. Based on the existence and uniqueness of one semi-discrete problem, two types of approximate solutions are introduced. By establishing some necessary uniform estimates for those approximate solutions, the existence and uniqueness of the corresponding parabolic problem are obtained. Moreover, the long time asymptotic behavior is established by the entropy functional method.
An Improved Generalized Finite Element Method for Electrical Resistance Tomography Forward Model
Bo Li,Jian Ming Wang,Qi Wang,Xiaojie Duan,Xiuyan Li 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.6
Electrical resistance tomography is a noninvasive imaging modality, where imperceptible currents are applied to the skin and the resulting surface voltages are measured. It has the potential to be of great value in industrial applications. One of the major problem of forward problem is its low efciency of fnite element computation in electrical resistance tomography and high demand in computational cost for industrial application. An advanced approach is proposed by generalizing the fnite element method frstly and then using PSO-SA algorithm to optimize the topology of FE model. Compared with conventional FEM or normal GFEM, a smaller number of nodes and elements with the proposed approach are required to achieve the same accuracy. The novelty of this paper relies on the frst to generalize the fnite mesh and optimize its topology in accordance with dissection results. Experiments from both simulation and prototype results demonstrate that it is capable of achieving better accuracy using less computational cost with the proposed approach
Machine learning-based prediction and performance study of transparent soil properties
Bo Wang,Hengjun Hou,Zhengwei Zhu,Wang Xiao 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.2
An indispensable process of geotechnical modeling with transparent soils involves analyzing images and soil property simulations. This study proposes an objective framework for quantitative analysis of the influential mechanism of three key factors, namely, different aggregate proportions (DAP), solvent ratio (SR), and solute solution ratio (SSR) on transparent soils’ transparency and shear strength. 125 groups of transparent soil samples considering these three factors were prepared to investigate their impact on transparency and shear strength through Elastic Net regression. Spearman correlation analysis was performed for transparency and shear strength. Furthermore, by comparing the performance of XGBoost, GBDT, Random Forest, and SVR after hyperparameter tuning in predicting transparency and shear strength, XGBoost proved to be the optimal machine learning model with the lowest MSE of 0.0048 and 0.0306 and was innovatively adopted to analyze how various factors affect the transparency and shear strength, thus enhancing the interpretability of machine learning. A ranking system, according to the importance scores of XGBoost, shows that SSR was the most important factor affecting both shear strength and transparency of transparent soils, with importance scores being 0.45 and 0.57, respectively. Our study may shed light on the preparation and performance study of transparent soils.