Facile and Effective Preparation of the Lotus Leaf-based Adsorbent by Exposing Cellulose Nanocrystal for Waste Water Treatment and Air Purification

Huiyu Yang,Ke Liu,Xin Liu,Yaling Wang,Keshuai Liu,Fengxiang Chen,Bo Deng,Weilin Xu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.2

One substantial plant waste, lotus leave was fabricated into lotus leave powder with different diameters by ball milling. The surface morphology, chemical composition, particle size, porosity parameters, crystal structure, and wettabilityof lotus leaf powders (LLPs) were analyzed by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), laser particle size analysis, N2 adsorption/desorption, X-ray diffraction (XRD) analysis, and water contact angle (WCA) analysis, respectively. The results showed that the micro- and nanoscale waxy papilla structures on the surface of the lotus leaf were gradually destroyed by mechanical forces along with extended balling time. Accompanied re-exposing of -OH affluent cellulose nanocrystals (CNCs) was proved by HR-TEM, XRD, and FTIR. FTIR also revealed a hydroxyl to carboxyl transition on the surface of CNCs. Both the re-exposure of CNCs and thereof chemical structure transition after ball millingmade the LLP a good candidate for pollutant adsorbent for dye, formaldehyde, and heavy metal ions.

Hybrid Visual Servoing for Rivet-in-hole Insertion Based on Super-twisting Sliding Mode Control

Hua Liu,Weidong Zhu,Huiyue Dong,Huiyue Dong 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.8

Aiming at solving the rivet-in-hole insertion problem of the complement riveting process, a novel hybridvisual servoing controller is proposed for an automatic drilling and riveting system, in which, combination ofvisual and laser sensor feedback is adopted to determine the relative pose errors of the rivet with respect to thehole. To compensate the system uncertainties, a super-twisting sliding mode controller (STSMC) is designed toprovide continuous control inputs, and the end-effector can move to the desired pose by exponentially decreasingthe feature errors. The proposed control scheme not only guarantees the stability of the control system but alsoprovides a robust and quick rivet spot-positioning in the presence of manipulator errors and external disturbancesof the riveting system. Finally, rivet-in-hole insertion experiments were conducted, the results show that accuratepositioning can be achieved within a finite time (1∼5s) which meets the demand of high-efficiency and flexibilityin the riveting process since it can achieve global convergence from any initial camera pose as long as the hole is inthe field-of-view (FOV) and the laser displacement sensors are in the working range at the beginning.

Green Synthesis and Characterization of Se Nanoparticles and Nanorods

Huiyu Chen,Ji-Beom Yoo,Yaqing Liu,Guizhe Zhao 대한금속·재료학회 2011 ELECTRONIC MATERIALS LETTERS Vol.7 No.4

Selenium nanoparticles and nanorods were successfully prepared in a mixed solvent of ethylene glycol and water at a relatively low temperature of 85°C. No other surfactant or template was employed, and glucose was used as a green and mild reducing reagent in the current synthesis. The volume ratio of ethylene glycol to water played an important role for controlling the shapes of selenium products. The obtained selenium samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectra, and UV-vis absorption spectra. The evolution process from amorphous selenium to a trigonal phase complied with a “solid-solution-solid” formation mechanism. HRTEM and SAED results indicate that the trigonal selenium nanorods grow along the [001] direction. This method might provide an environmentally-friendly and low cost route for the synthesis of other related nanomaterials with controlled morphologies.

Synthesis and Characterization of Hollow Silver Spheres at Room Temperature

Huiyu Chen,Yaqing Liu,Guizhe Zhao 대한금속·재료학회 2011 ELECTRONIC MATERIALS LETTERS Vol.7 No.2

Hollow silver spheres were synthesized at room temperature using sodium borohydride (NaBH4) as the reducing reagent and poly (vinyl pyrrolidone) (PVP) as the surfactant. The size of the synthesized hollow spheres ranged from 120 to 250 nm, and the surface was composed of many smaller silver nanoparticles. The asobtained product was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-vis absorption spectra. The amount of PVP had a significant effect on the morphology of the resultant silver samples. With an increasing concentration of PVP, the silver products possessed rod-like and shuttle-like shapes. The UV-vis spectrum demonstrated that the broad absorption peak centered at 417 nm resulted from the surface plasmon resonance (SPR) excitation of silver.

Formation of Flower-Like Magnesium Hydroxide Microstructure via a Solvothermal Process

Huiyu Chen,Chunju Xu,Yaqing Liu,Guizhe Zhao 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.5

Flower-like magnesium hydroxide (Mg(OH)2) microstructure composed of many sheet-like nanopetals was prepared on a large scale via a solvothermal reaction at 200°C for 24 h. Water and ethanol mixed solution was employed as solvent and no additional surfactant was involved during the synthetic process. The Mg(OH)2microflowers were characterized by XRD, SEM, HRTEM, and UV-vis techniques. The average size of single flower is about 2 μm and the thickness of the petals ranges from 20 to 30 nm. The temperature and volume ratio of water to ethanol were found to be key roles for controlling the morphology of Mg(OH)2 products. The assembled petals of the Mg(OH)2 microflowers became thicker and smoother with the amount of water decreased in the mixed solvent. The present method is low cost, simple handle and environmentally benign,thus, it can be relatively easy to be scaled up for industrial production.

A facile, green synthesis of biomass carbon dots coupled with molecularly imprinted polymers for highly selective detection of oxytetracycline

Haochi Liu,Lan Ding,Ligang Chen,Yanhua Chen,Tianyu Zhou,Huiyu Li,Yuan Xu,Li Zhao,Ning Huang 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-

Biomass carbon dots (CDs) prepared by sweet potato peels were superior fluorophores with low toxicity and excellent photostability. A novel designed fluorescence probe for specific recognition and sensitive detection of oxytetracycline (OTC) was fabricated with CDs and molecularly imprinted polymer (MIP). The quenching of CDs happened when rebinding with OTC due to electron-transfer-induced fluorescence quenching mechanism. The fluorescence probe was successfully applied in honey with the recoveries ranging from 90.2% to 97.3%. The detection limit of OTC was 15.3 ng mL−1. This work provides promising perspectives that the development of fluorescent MIP will be valuable for rapid analysis in complex samples.

The Construction of the Heterostructural Bi2O3/g-C3N4 Composites with an Enhanced Photocatalytic Activity

Jinhua Zhang,Huiyue Qian,Wencheng Liu,Hao Chen,Yang Qu,Zhidong Lin 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.6

A heterostructural composite composed of g-C3N4 and Bi2O3 was achieved by the one-pot and thermal-induced polycondensation method using melamine and Bi(NO3)3 as precursor at 550 ℃ under air atmosphere. The crystalline phase, components and morphologies of the as-prepared composites were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Besides, the photocatalytic activity of composites was evaluated by degrading RhB aqueous solution at room temperature under visible light irradiation. Compared with bulk g-C3N4, the photocatalytic efficiency of the 0.5% Bi2O3/g-C3N4 (Bi–CN) was increased by up to four times. The introduction of Bi2O3 enhances not only the light absorption ability, but also the separation of photogenerated electron–hole pairs.

Detecting LDoS Attacks based on Abnormal Network Traffic

( Kai Chen ),( Huiyu Liu ),( Xiaosu Chen ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.7

By sending periodically short bursts of traffic to reduce legit transmission control protocol (TCP) traffic, the low-rate denial of service (LDoS) attacks are hard to be detected and may endanger covertly a network for a long period. Traditionally, LDoS detecting methods mainly concentrate on the attack stream with feature matching, and only a limited number of attack patterns can be detected off-line with high cost. Recent researches divert focus from the attack stream to the traffic anomalies induced by LDoS attacks, which can detect more kinds of attacks with higher efficiency. However, the limited number of abnormal characteristics and the inadequacy of judgment rules may cause wrong decision in some particular situations. In this paper, we address the problem of detecting LDoS attacks and present a scheme based on the fluctuant features of legit TCP and acknowledgment (ACK) traffic. In the scheme, we define judgment criteria which used to identify LDoS attacks in real time at an optimal detection cost. We evaluate the performance of our strategy in real-world network topologies. Simulations results clearly demonstrate the superiority of the method proposed in detecting LDoS attacks.

Application of Three-Dimensional Solubility Parameter in Diffusion Behavior of Rubber-Solvent System and Its Predictive Power in Calculating the Key Parameters

Xingwang Jiang,Yupeng Hao,Huiyu Wang,Jieyun Tu,Guangyong Liu 한국고분자학회 2022 Macromolecular Research Vol.30 No.4

Three different rubbers, hydrogenated nitrile butadiene rubber (HNBR), ethylene vinyl acetate copolymer (EVM) and ethylene propylene diene rubber (EPDM), and two blends, HNBR/EVM and HNBR/EPDM were compounded both with and without fillers, and were vulcanized with the same peroxide curing system. Peppas- Sahlin model was used to explain the diffusion mechanism of solvents in rubber vulcanizates. Transport parameters including diffusion coefficient, sorption coefficient and permeation coefficient were calculated and correlated with Flory-Huggins interaction parameters (χ). The Peppas-Sahlin model dealing with diffusion behaviors of solvents shows high degree of fitting for both unfilled and filled rubber-solvent systems. With the addition of carbon black, the diffusion coefficient increases while the sorption and permeation coefficients decrease. The sorption coefficient increases linearly with the permeation coefficient. New Flory-Huggins interaction parameter (χN) calculated by threedimensional solubility parameters shows better predictive power in diffusion behaviors than the traditional one (χT). By mathematical fitting, a linear relationship can be obtained between the maximum swelling ratio and χN, while an exponential relationship is gained for the permeation coefficient. The discovery of this rule connects three-dimensional solubility parameters with the swelling of polymer in solvent, which provides experimental basis for the further study of the medium resistance of polymer.

Deeper SSD: Simultaneous Up-sampling and Down-sampling for Drone Detection

( Han Sun ),( Wen Geng ),( Jiaquan Shen ),( Ningzhong Liu ),( Dong Liang ),( Huiyu Zhou ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.12

Drone detection can be considered as a specific sort of small object detection, which has always been a challenge because of its small size and few features. For improving the detection rate of drones, we design a Deeper SSD network, which uses large-scale input image and deeper convolutional network to obtain more features that benefit small object classification. At the same time, in order to improve object classification performance, we implemented the up-sampling modules to increase the number of features for the low-level feature map. In addition, in order to improve object location performance, we adopted the down-sampling modules so that the context information can be used by the high-level feature map directly. Our proposed Deeper SSD and its variants are successfully applied to the self-designed drone datasets. Our experiments demonstrate the effectiveness of the Deeper SSD and its variants, which are useful to small drone’s detection and recognition. These proposed methods can also detect small and large objects simultaneously.