Reduced graphene oxide/polypyrrole composite: an advanced electrode for high-performance symmetric/asymmetric supercapacitor

Liu Guijing,Shi Yanying,Wang Lei,Song Yadong,Gao Shanmin,Liu Dong,Fan Leqing 한국탄소학회 2020 Carbon Letters Vol.30 No.4

Polypyrrole (PPy) decorated on reduced graphene oxide (rGO) flms is successfully prepared with pyrrole (Py) monomers and rGO through one-step combining oxidation with polymerization reaction. Compared with the pure individual compo�nents, rGO/PPy compound turns out better electrochemical characteristics owing to the introduction of rGO sheets, which improves the specifc surface area and the conductivity of composite material. When the amount of rGO is 10% of the total, the rGO/PPy compound delivers the best capacitance of 389.3 F g−1 at 1.0 A g−1 in a three-electrode system and 266.8 F g−1 at 0.25 A g−1 in the symmetric supercapacitor system. In addition, asymmetric device (rGO/PPy//AC) has been success�fully fabricated using optimized rGO/PPy compound as positive electrode, activated carbon as negative electrode (AC) and 1 M Na2SO4 aqueous solution as electrolyte. The device obtains long cycle stability under the high-voltage region from 0 to 1.6 V, meanwhile displaying the satisfed energy density of 19.7 Wh kg−1 at 478.1 W kg−1. Besides, the rGO/PPy//AC device presents satisfactory rate capability and long life time.

Cenozoic tectonic evolution in the western Qaidam Basin inferred from subsurface data

Yadong Wang,Junsheng Nie,Tao Zhang,Guoqiang Sun,Xin Yang,Yuhu Liu,Xingwang Liu 한국지질과학협의회 2010 Geosciences Journal Vol.14 No.4

It is an agreement that collision of Indian and Asian plates causes uplift of the Tibet Plateau. However, great controversy exists about uplifting history and mechanisms of the Tibetan Plateau. Uplift history of the Tibetan Plateau has been well recorded in the Qaidam Basin, located in the northern margin of the Tibet Plateau. In this paper, we recognize and classify faults recorded by subsurface seismic data in the western Qaidam Basin. In addition, we reconstruct the Cenozoic deformation history of the Qaidam Basin based on balanced section of 5 seismic profiles. The results indicates that 1) Faults in the western Qaidam Basin can be classified as growth faults and non-growth faults, and the growth faults could be divided into three subcategories. 2) According to timing and manner of fault activities, faults and strata in the western Qaidam Basin could be divided into two structural layers: the lower (Lulehe Fm-Xia Youshashan Fm) and the upper (Shang Youshashan Fm-Qigequan Fm) layer. 3) The western Qaidam Basin has experienced two intensive tectonic deformations: the first phase occurs at 43.8−22 Ma (Middle Eocene−Early Miocene), which reached peak at 31.5 Ma (Early Oligocene); the second phase occurred between 14.9 and 0 Ma (Middle Miocene−Present), and the second phase is stronger than the first phase. Recognizing early fault activities confirm previous results that northern Tibet has sensed collision between the India and the Asia shortly after the collision. However, our results here emphasize that the northern Tibet has experienced another phase of shortening and uplift in the late Neogene. It was the two-stage tectonic activities that work together to produce the current Tibetan Plateau.

Depth tracking of occluded ships based on SIFT feature matching

Yadong Liu,Yuesheng Liu,Ziyang Zhong,Yang Chen,Jinfeng Xia,Yunjie Chen 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.4

Multi-target tracking based on the detector is a very hot and important research topic in target tracking. It mainly includes two closely related processes, namely target detection and target tracking. Where target detection is responsible for detecting the exact position of the target, while target tracking monitors the temporal and spatial changes of the target. With the improvement of the detector, the tracking performance has reached a new level. The problem that always exists in the research of target tracking is the problem that occurs again after the target is occluded during tracking. Based on this question, this paper proposes a DeepSORT model based on SIFT features to improve ship tracking. Unlike previous feature extraction networks, SIFT algorithm does not require the characteristics of pre-training learning objectives and can be used in ship tracking quickly. At the same time, we improve and test the matching method of our model to find a balance between tracking accuracy and tracking speed. Experiments show that the model can get more ideal results.

Studies on Shoot Regeneration from Leaf Pieces of Rubus in Vitro

Yadong Li,Wei An,Shuying Liu,Zhidong Zhang,Lin Wu 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Preparation and photoluminescence properties of the Eu2+, Sm3+ co-doped Li2SrSiO4 phosphors

Lijuan Liu,Panli You,Guangfu Yin,Xiaoming Liao,Zhongbing Huang,Xianchun Chen,Yadong Yao 한국물리학회 2012 Current Applied Physics Vol.12 No.4

A series of Eu2+ and Sm3+ co-doped Li2SrSiO4 phosphors are prepared by the high temperature solidstate reaction. The morphology, structure and spectroscopic properties of the prepared samples are characterized by scanning electron microscopy, X-ray diffraction, diffuse reflection spectra, photoluminescence spectra and electron paramagnetic resonance spectra, respectively. The effect of Sm3þdoping concentration on the photoluminescence intensity of the prepared samples is also investigated. The results indicate that the crystal structure of Li2SrSiO4 is not changed with the Eu2+, Sm3+ co-doping. The spherical-like particle size of the obtained product is about 20-30 nm in diameter. When the Sm3+ concentration is 0.3 mol% and the Eu2+ concentration is 0.7 mol%, the phosphors show the maximum emission intensity, which is 50% higher than that of Eu2+ doped Li2SrSiO4. Excited at 420 nm, the phosphor presents a single broad emission band peaking at 558 nm, which is ascribed to the 4f65d1 / 4f7 transitions of Eu2+ and 4G5/2 / 6H5/2 and 4G5/2 / 6H7/2 transitions of Sm3+. The Commission International de I0Eclairage chromaticity coordinates of Li2SrSiO4:0.7 mol% Eu2+, 0.3 mol%Sm3+ are x = 0.28, y = 0.28. A series of Eu2+ and Sm3+ co-doped Li2SrSiO4 phosphors are prepared by the high temperature solidstate reaction. The morphology, structure and spectroscopic properties of the prepared samples are characterized by scanning electron microscopy, X-ray diffraction, diffuse reflection spectra, photoluminescence spectra and electron paramagnetic resonance spectra, respectively. The effect of Sm3þdoping concentration on the photoluminescence intensity of the prepared samples is also investigated. The results indicate that the crystal structure of Li2SrSiO4 is not changed with the Eu2+, Sm3+ co-doping. The spherical-like particle size of the obtained product is about 20-30 nm in diameter. When the Sm3+ concentration is 0.3 mol% and the Eu2+ concentration is 0.7 mol%, the phosphors show the maximum emission intensity, which is 50% higher than that of Eu2+ doped Li2SrSiO4. Excited at 420 nm, the phosphor presents a single broad emission band peaking at 558 nm, which is ascribed to the 4f65d1 / 4f7 transitions of Eu2+ and 4G5/2 / 6H5/2 and 4G5/2 / 6H7/2 transitions of Sm3+. The Commission International de I0Eclairage chromaticity coordinates of Li2SrSiO4:0.7 mol% Eu2+, 0.3 mol%Sm3+ are x = 0.28, y = 0.28.

A General Self-Propagating High-Temperature Synthesis Method for Fast and Easy Preparation of Metal Oxide Nanostructures from Low Melting Point Metals

Nian Liu,Guodong Zhang,Yadong Xiao,Zhifang Peng 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.1

Different metal oxide nanostructures including SnO2 nanowires, SnO2 nanoparticles, ZnO nanorods, ZnO nanoparticles, Al2O3 nanoparticles, SiO2 nanoarray, and SnO2–SiO2 core–shell nanoparticles, can be selectively synthesized by Self-propagating High-temperature Synthesis (SHS) method with different reaction systems. This method can be easily applied to synthesize metal oxide nanostructures with high yield and excellent purity from low melting point metals in a very short time at low cost without the need for any sophisticated equipment. The composition of reaction system has a crucial influence on the reaction temperature and morphology of the end products. Compared with nanoparticles, nanowires or nanorods can be obtained at lower reaction temperature. And introducing the chemical containing silicon to the reaction system allows the formation of SiO2 nanoarray and SnO2–SiO2 core–shell nanoparticles.

A Trajectory Substitution Privacy Protection Scheme in location-based services

( Cheng Song ),( Yadong Zhang ),( Xinan Gu ),( Lei Wang ),( Zhizhong Liu ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.9

Aimed at the disclosure risk of mobile terminal user’s location privacy in location-based services, a location-privacy protection scheme based on similar trajectory substitution is proposed. On the basis of the anonymized identities of users and candidates who request LBS, this scheme adopts trajectory similarity function to select the candidate whose trajectory is the most similar to user’s at certain time intervals, then the selected candidate substitutes user to send LBS request, so as to protect user’s privacy like identity, query and trajectory. Security analyses prove that this scheme is able to guarantee such security features as anonymity, non-forgeability, resistance to continuous query tracing attack and wiretapping attack. And the results of simulation experiment demonstrate that this scheme remarkably improve the optimal candidate’ trajectory similarity and selection efficiency.

SOMEDGRA: A case retrieval method for machine tool product configuration design

Pengjia Wang,Yadong Gong,Hualong Xie,Yongxian Liu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7

Case based design is an intelligent method which involves retrieving the most similar previous case to provide a solution of a new decision problem. However, conventional case based design approaches are too reliant on experts’ experiences. A new case retrieval method SOMEDGRA that combines Self-organizing map (SOM) and Euclidean distance (ED) method as well as Grey relational analysis (GRA) method is proposed in case based design. SOM is used to reduce the retrieval range and increase the retrieval efficiency, and ED is used to evaluate the similarity of cases comprehensively. To ensure that the final case has the best overall performance, an evaluation method of similar cases based on GRA is proposed to evaluate similar cases to select the most suitable case. The case study and result on an HTC series machine tool product show that the proposed method is effective, accurate and rapid in the process of product configuration.

The precipitation of three Ca-P phase whiskers from an acid solution through hydrolysis of urea

Yunqing Kang,Yunshan Liu,Zhongbing Huang,Yadong Yao,Xiaoming Liao,Li Liao,Guangfu Yin 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.2

Hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and dicalcium phosphate (DCP) whiskers with high aspect ratio and good crystallinity were successfully prepared by hydrolysis of urea in acid solutions at 90oC for 96 h. The precipitated whiskers were characterized by XRD, SEM and TEM. The lengths and aspect ratios of whiskers could be controlled by the precipitation agent, urea, with a proper incubation time. Results revealed good morphology and crystallinity of the precipitated whiskers without any impurities. TEM indicated single crystal diffraction patterns of HA and β-TCP were clearly identified. The high aspect ratio of whiskers could be potentially used as the scaffold in tissue engineering or filler in composite biomaterials to enhance mechanical properties. Hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and dicalcium phosphate (DCP) whiskers with high aspect ratio and good crystallinity were successfully prepared by hydrolysis of urea in acid solutions at 90oC for 96 h. The precipitated whiskers were characterized by XRD, SEM and TEM. The lengths and aspect ratios of whiskers could be controlled by the precipitation agent, urea, with a proper incubation time. Results revealed good morphology and crystallinity of the precipitated whiskers without any impurities. TEM indicated single crystal diffraction patterns of HA and β-TCP were clearly identified. The high aspect ratio of whiskers could be potentially used as the scaffold in tissue engineering or filler in composite biomaterials to enhance mechanical properties.

Degradation of 1,4-dioxane by Newly Isolated Acinetobacter sp. M21 with Molasses as the Auxiliary Substrate

Peng Wang,Tingchen Cui,Yadong Yang,Jialu Li,Yaoming Su,Na Liu,Hong-Mei Li 한국생물공학회 2022 Biotechnology and Bioprocess Engineering Vol.27 No.3

The elimination of 1,4-dioxane (dioxane), a persistent organic pollutant, is a great challenge owing to its high hydrophilicity and chemical stability. Cometabolic bioremediation technology is an effective approach to remove many organic pollutants. Because of its eco-friendly and inexpensive properties, molasses is widely used as an auxiliary biomaterial to clean up compound-contaminated sites. In this study, a newly isolated bacterium Acinetobacter sp. M21 could effectively remove dioxane using molasses without any apparent lag phase. Under the optimized molasses dosage of 0.3%, M21 could remove 500 mg/L dioxane by 60.0 ± 2.8% within 20 days with a maximum dioxane degradation rate of 1.3 ± 0.2 mg-dioxane/L/h in the first day, and exhibited extraordinary dioxane tolerance up to 1,000 mg/L, while so high dose of dioxane negatively affected the cell growth. The degradation pathway of dioxane was also determined, and was supported by the detection of 2-hydroxyethoxyacetic acid as the key metabolite of dioxane. High level degradation activity of M21 to 20 mg/L dioxane was maintained over a variable of pH (5-11), temperatures (15-45°C), and salinities (up to 8%, as NaCl wt). This is the first report linking the cometabolism of dioxane and molasses by Acinetobacter sp. M21, a bacterium that shows great potential for field dioxane bioremediation.