Preparation of decorative slag glass-ceramics and research on the solidification of heavy metals

Yang Tang,Xiaodong Hao,Zhenxiang Fang,Xinyu Bai,Guangyu Wang,Hongxia Zhang,Leibo Deng,Hua Chen,Ming Zhao,Yongsheng Du 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.1

Glass-ceramics with different CuO additions were prepared with Fe2O3 and Cr2O3 as composite nucleating agents, rare earthcontainingblast furnace slag (REBFS) as the main raw material. The existence state and stability of heavy metals Cu, Mn andCr in glass-ceramics were investigated. The results showed that Cr ions contributed to the generation of spinel phase, whileCu ions and Mn ions can enter the spinel crystal and exist stably, which indicated that there was a synergistic solidificationof Cu, Mn and Cr. The depolymerization effect of the copper ions contributed to the transformation of the crystal morphologyfrom dendrites to spherulites. Moreover, the increase in CuO contents promoted glass-ceramics from green to copper red. Based on the leaching experimental data analysis of heavy metals in glass-ceramics, the leaching concentration of heavy metalsCu, Cr and Mn were much lower than the standard leaching toxicity limit of hazardous waste (GB5085.3–2007, China). Theresults showed that the conversion of REBFS into environmentally friendly glass-ceramics can realize solid waste resourceutilization.

Tangential Damping Model of Bolted Joint with the Physics-Based Friction Coefficient

Yongsheng Zhao,Hongchao Wu,Congbin Yang,Zhifeng Liu,Qiang Cheng 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.5

The stiff ness and damping modeling of joint surfaces are important for analyzing the dynamic characteristics of bolted joints, which has a great influence on the working precision of the machine tool. In this paper, a damping model is presented to predict the tangential damping of the joint accurately. The fractal theory is introduced to characterize the rough contact surface by using fractal dimension D and fractal roughness parameter G. For each micro-contact, the contact region can be divided into stick section and slip one. The energy dissipation of the micro-contact, which can be described as the tangential damping of bolted joint, emerges in the slip section. The physics-based friction coefficient is introduced to define the energy dissipation function based on the relationship between the deformation of micro-contact and the normal pressure. The energy dissipation factor and the proportional damping of the micro-contact can be obtained. The total tangential damping of bolted joint can be obtained by integrating the whole contact surfaces. Experimental set-up is designed to verify the proposed model. Compared with the constant friction coefficient damping model, the results show that the proposed model can more accurately describe the tangential damping of bolted joint.

Effect of Ar dilution flow rate on LPCVD a boron-doped carbon coating from BCl3-C3H6-H2-Ar mixtures

Yongsheng Liu,Litong Zhang,Laifei Cheng,Wenbin Yang,Yongdong Xu 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.3

A boron-doped carbon coating was deposited from a BCl3-C3H6-H2-Ar system by LPCVD. The effects of the Ar dilution flow rate on deposition rates, morphologies, compositions and bonding states were investigated. Deposition rates were almost the same, about 250 nm/h with different Ar dilution flow rate. Surface morphologies were also almost the same. The flat conchoidal aspect of the fracture surface transformed to a laminated structure with an increase in the Ar dilution flow rate. The carbon concentration was above 76.3 at.%, and the boron concentration was less than 17.9 at.%. The boron concentration increased with an increase in the Ar dilution flow rate, corresponding to a decreasing carbon concentration. The main bonding state of boron was B-sub-C and BC2O. The whole deposition process was dominated by a PyC formation reaction, which led to almost the same deposition rate with different Ar dilution flow rates. A boron-doped carbon coating was deposited from a BCl3-C3H6-H2-Ar system by LPCVD. The effects of the Ar dilution flow rate on deposition rates, morphologies, compositions and bonding states were investigated. Deposition rates were almost the same, about 250 nm/h with different Ar dilution flow rate. Surface morphologies were also almost the same. The flat conchoidal aspect of the fracture surface transformed to a laminated structure with an increase in the Ar dilution flow rate. The carbon concentration was above 76.3 at.%, and the boron concentration was less than 17.9 at.%. The boron concentration increased with an increase in the Ar dilution flow rate, corresponding to a decreasing carbon concentration. The main bonding state of boron was B-sub-C and BC2O. The whole deposition process was dominated by a PyC formation reaction, which led to almost the same deposition rate with different Ar dilution flow rates.

Analysis of the Partial Axial Load of a Very Thin-Walled Spur-Gear (Flexspline) of a Harmonic Drive

Congbin Yang,Qiushi Hu,Zhifeng Liu,Yongsheng Zhao,Qiang Cheng,Caixia Zhang 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.7

Harmonic drives are the core components to enable movement in industrial robots. Unfortunately, the deformation of flexspline causes obvious partial axial load on gear engagement. This synthetic error leads to a series of additional problems, such as the deterioration of transmission quality, and the reduction of both precision and fatigue life. This study focuses on a harmonic drive with a double circular-arc tooth profile. A coordinate transformation is carried out based on the kinematics of harmonic drives. On this basis, the conjugate tooth profile of a circular spline is derived. A simulation model is developed based on the motion relationship for harmonic transmission. The effect of inhomogeneity of the load distribution on the surface of the gear teeth was investigated using the partial axial-load index. The effect of different factors on the partial axial load is analyzed. To reduce the effect of partial axial load of flexspline, we select a suitable material and wall thickness. For a certain practical range, both tooth width and chamfering of the flexspline teeth help reduce the partial axial load and increase the flexspline length. These conclusions enable improvements of future designs of reliable flexspline.

A Biocompatible and Sustainable Anti-ultraviolet Functionalization of Cotton Fabric with Nanocellulose and Chitosan Nanocomposites

Xue Yang,Ziyang Wang,Yongsheng Zhang,Wei Liu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.11

For improving the ultraviolet (UV) protection property of cotton fabric and exploiting ecological cotton textiles,cotton fabric was modified with a kind of biocompatible and nontoxic of chitosan (CS)/nanocellulose (NCs) nanocompositesusing a pad-dry-cure process. The effect of particle size of NCs on the morphology and property of CS/NCs cotton fabrics werecarefully investigated by SEM, FTIR, and mechanical property, water wettability, UV protection and laundering durabilityanalysis. The results revealed that the CS/NCs coated fabrics performed excellent UV protection ability as well as a goodlaundering durability. The UPF values of all the CS/NCs coated fabrics were much higher than that of untreated fabric evenafter 30 cycles of laundering. Moreover, the particle size of NCs had a negative effect on the UV protection ability of CS/NCscoated fabric. Meanwhile, coated with CS/NCs nanocomposites was benefit to enhance the mechanical property, andhydrophobicity of cotton fabric.

Analysis and Optimization of an Internal Feedback Hydrostatic Turntable Oil Pad Power Consumption Based on Finite Difference Method

Congbin Yang,Shuaihua Shao,Yanhong Cheng,Zhifeng Liu,Yongsheng Zhao 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.12

The hydrostatic turntable is a critical component of numerous CNC machine tools, as it performs a supporting function and enables precise rotary motion. To ensure that high-precision CNC machines can operate under heavy loads, it is imperative to minimize power consumption. The power consumption of a hydrostatic turntable is affected by various factors, such as oil viscosity, initial oil film thickness, and oil pad structure. This study focuses on investigating a hydrostatic turntable with internal feedback. The Reynolds equation of the sector oil pad is solved using the finite difference method to establish the pressure distribution model. Subsequently, the study examines the power consumed by the axial oil pad at different initial oil film thickness, lubricating oil viscosity, and sealing edge width. To minimize power consumption caused by the axial oil pad, this paper employs the genetic algorithm to identify optimal design parameters within specified constraints. Additionally, the load-bearing performance of the optimized axial oil pad is checked to ensure that the load-bearing capacity and stiffness meet the requirements. Finally, the use of simulation software for oil pads in finite element simulation can preliminarily demonstrate the reliability of the proposed method.

Research on Meshing Characteristics of Strain Wave Gearing with Three Different Types of Tooth Profiles

Congbin Yang,Honglie Ma,Tao Zhang,Zhifeng Liu,Yongsheng Zhao,Qiushi Hu 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.10

Harmonic drive (HD) is one of the core components of the robot joint. Studies show that tooth shape design and meshing characteristics of the HD directly affect the motion control accuracy and vibration characteristics of the robot. In the present study, common coordinate systems are established for three tooth profiles to analyze the differences between them. To this end, expressions for the double circular arc common-tangent tooth profile (DCTP), cycloid common tangent tooth profile (CCTP), and the involute tooth profile (ITP) are established in the same coordinate system. By applying the envelope conjugate theory, the conjugate existent domain (CED) and conjugate tooth profile (CTP) of the HD transmission are solved independently for each profile. Furthermore, the influences of tooth profile parameters on both the CTP and CED are analyzed. Obtained results show that both the DCTP and CCTP have more robust envelope processes when compared with the ITP. Moreover, it is found that both profiles can achieve the second conjugate and two-point conjugate engagement through applying variations in the tooth shape design parameters. It is concluded that meshing performances of the DCTP and CCTP are better than that of the ITP, providing guidelines for the future development of the harmonic reducer tooth shape design.

Effect of heat treatment on the crystallization toughening of tailing-derived glass-ceramics

Du Yongsheng,Yang Xiaowei,Zhang Hongxia,Zhang Xuefeng,Zhao Ming,Chen Hua,Ouyang Shunli,Li Baowei 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.12

The effect of heat treatment to a parent glass of the composition CaO-MgO-Al2O3-SiO2 (CMAS) on the course ofcrystallization and properties of the Bayan Obo east mine tailing glass-ceramics is examined. The crystallization behavior,phase composition, morphology and structure of glass-ceramics are characterized. The results indicate that the phases formedin the glass-ceramics are augite and the initial nucleation phases are magnetite, which can be proved by differential scanningcalorimetry (DSC), X-ray diffraction (XRD) and scanning transmission electron microscope (STEM). Heat treatment plays asignificant role in improving the crystallization process, fracture characteristics, modulus and bending strength. All of theseproperties reach a maximum for the fully crystallized glass-ceramic. Scanning electron microscope (SEM) and atomic forcemicroscope (AFM) are used to reveal the topography of the fracture surfaces. The intergranular fracture can be observed onthe fracture surface.

QLGR: A Q-learning-based Geographic FANET Routing Algorithm Based on Multi-agent Reinforcement Learning

( Xiulin Qiu ),( Yongsheng Xie ),( Yinyin Wang ),( Lei Ye ),( Yuwang Yang ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.11

The utilization of UAVs in various fields has led to the development of flying ad hoc network (FANET) technology. In a network environment with highly dynamic topology and frequent link changes, the traditional routing technology of FANET cannot satisfy the new communication demands. Traditional routing algorithm, based on geographic location, can “fall” into a routing hole. In view of this problem, we propose a geolocation routing protocol based on multi-agent reinforcement learning, which decreases the packet loss rate and routing cost of the routing protocol. The protocol views each node as an intelligent agent and evaluates the value of its neighbor nodes through the local information. In the value function, nodes consider information such as link quality, residual energy and queue length, which reduces the possibility of a routing hole. The protocol uses global rewards to enable individual nodes to collaborate in transmitting data. The performance of the protocol is experimentally analyzed for UAVs under extreme conditions such as topology changes and energy constraints. Simulation results show that our proposed QLGR-S protocol has advantages in performance parameters such as throughput, end-to-end delay, and energy consumption compared with the traditional GPSR protocol. QLGR-S provides more reliable connectivity for UAV networking technology, safeguards the communication requirements between UAVs, and further promotes the development of UAV technology.

Molecular Imprinting Polymers Based on Boric Acid-Modified CdTe QDs for Sensitive Detection of Glucose

Bo Hu,Yang Lu,Keyu Cui,Yongsheng Yan 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.4

In this study, a novel imprinted polymer based on 3-aminophenylboronic acid (APBA)-functionalized CdTe quantum dots (QDs) was synthesized and used to sensitively and selectively detect glucose. In the process of synthesis, the boronic acid in the APBA could combine covalently with vicinal diol compounds, directing imprinting process, and the APBA-modified CdTe QDs were used as the solid supports. By this method, the prepared molecular imprinting polymers (MIPs)-APBA/CdTe QDs show high selectivity, high sensitivity and good stability. Under optimal conditions, a linear relationship was obtained covering the linear range of 0–1.5 mmol/L with a correlation coefficient of 0.99833 and a high imprinting factor about 5.71. Furthermore, the prepared MIPs-APBA/CdTe QDs were successfully applied to detect glucose in human serum samples. This work provides a new way to synthesize an excellent stability and efficient imprinted polymer based on CdTe QDs for convenient, fast and highly selective detection of glucose.