Effect of reaction conditions on one-step preparation of 1H,1H,2H,2HPerfluorooctyltrimethoxysilane by catalytic hydrosilylation over RuCl33H2O catalysts

Feihong Ye,Liping Li,Jianyin Xu,Lu Zhou 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

Synthesization of 1H,1H,2H,2H-Perfluorooctyltrimethoxysilane through solvent-free hydrosilylation of1H,1H,2H-perfluoro-1-octene with trimethoxysilane was efficiently conducted over the RuCl33H2O catalyst. The synergistic action of Ru3+ as the active center and the strong electronegativity of Cl to attractthe electron of the electron-donating group –OCH3 in trimethoxysilane, activated the Si-H and thus promotedthe reaction. The influences of different reaction conditions including feed order, feed ratio, catalystdosage, reaction temperature and reaction time on the reaction yield were fully investigated, toconclude the optimized condition to achieve a yield of 86.80% was the feed of 1.2 mol trimethoxysilaneper mole of 1H,1H,2H-perfluoro-1-octene, together with the addition of 9.56 104 mol RuCl33H2O permole of trimethoxysilane, at 80 C for 4 h; while the additive of CuCl to RuCl33H2O catalyst could furtherimprove the reaction yield at 50℃. Finally, after understanding the activity of Ru with different valencestate, the reaction mechanism was also proposed.

Tooth Thickness Error Analysis of Straight Beveloid Gear by Inclined Gear Shaping

Feihong Zhu,Chaosheng Song,Caichao Zhu,Xuesong Du 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.4

In this paper, two approaches to calculate the tooth thickness error (TTE) of straight beveloid gear by tilt-type gear shaper were proposed. The first calculation approach of TTE was established by considering the change of pitch circle radius during the gear slotting process. The analytical tooth surface model of straight beveloid gear was derived by inclined gear shaping, and the tooth surface point set was obtained. Then, another calculation methodology of TTE was established based on the analytical straight beveloid gear model. Two approaches were employed to calculate the TTE of internal and external straight beveloid gear, respectively. And they were employed to validate each other, and the results show a good consistency. The influences of design parameters on TTE was analyzed. Results show that the internal/external straight beveloid gears have a convex/concave TTE along the tooth width direction while cutting by tilt-type gear shaper, which makes the tooth thickness of the heel and toe sides of beveloid gear thinned/thickened, respectively. The TTE of internal and external beveloid gear both increase with the increase of design cone angle, and decrease with the increase of modulus and number of teeth. For the same macro gear design parameters, the TTE of external beveloid gear is smaller than that of internal beveloid gear. The results of the two approaches show good consistency at the middle of tooth surface. The maximum difference between the results of two approaches gradually increases away from the middle of tooth surface, and it is positively correlated with the value of TTE.

Robust Cooperative Relay Beamforming Design for Security

( Xiangwu Gong ),( Feihong Dong ),( Hongjun Li ),( Wei Shao ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.11

In this paper, we investigate a security transmission scheme at the physical layer for cooperative wireless relay networks in the presence of a passive eavesdropper. While the security scheme has been previously investigated with perfect channel state information(CSI) in the presence of a passive eavesdropper, this paper focuses on researching the robust cooperative relay beamforming mechanism for wireless relay networks which makes use of artificial noise (AN) to confuse the eavesdropper and increase its uncertainty about the source message. The transmit power used for AN is maximized to degrade the signal-to-interference-plus-noise-ratio (SINR) level at the eavesdropper, while satisfying the individual power constraint of each relay node and worst-case SINR constraint at the desired receiver under a bounded spherical region for the norm of the CSI error vector from the relays to the destination. Cooperative beamforming weight vector in the security scheme can be obtained by using S-Procedure and rank relaxation techniques. The benefit of the proposed scheme is showed in simulation results.

Effects of Sulfur Introduction on the UV and the Visible Emission Properties of ZnO

Hongying Guo,Feihong Jiang,Run Yuan,Jun Zhang,Yuanping Sun,Yifan Liu,Yongxin Qiu,Taofei Zhou,Xionghui Zeng,Baoshun Zhang,Ke Xu,Hui Yang 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.4

Hexagonal ZnO particles have been synthesized by using the hydrothermal method with differentsulfur concentrations in the reaction solutions. Structural and optical characterizations have beenconducted to study the effects of the sulfur in the reaction solutions on the properties of thesynthesized ZnO in the ultraviolet (UV) and the visible (VIS) bands. The existance of sulfur inthe solutions can help to introduce compression strain along the a axis and an opposite trend forthe parameter c with strain inside the formed ZnO particles, which means the total strain in thesamples is presented along the c axis. The average size of the ZnO particles, as calculated fromSEM images, shows the same trend as the strain in the samples. The increasing incorporation ofsulfur causes an increase in the VIS luminescence band, which can be attributed to an increase inthe number of sulfur-induced defects.

Hybrid Full Frequency Precoding for Integrated Remote Wireless Sensor and Multibeam Satellite Networks

( Hongjun Li ),( Feihong Dong ),( Xiangwu Gong ),( Changliang Deng ),( Luliang Jia ),( Jingchao Wang ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.6

This paper investigates an efficient transmission scheme for the remote wireless sensors to receive information which is rarely discussed in the integrated remote wireless sensor and multibeam satellite networks (IWSMSNs). The networks can be employed to exchange sensing information for emergency scenario, ocean scenario, and so on, which are isolated from available terrestrial networks. As the efficient transmission link is important to the IWSMSNs, we propose a hybrid full frequency (HFF) precoding by taking advantage of frequency reuse and multiple-input multiple-output (MIMO) precoding. Considering energy efficiency and sinks fairness are crucial to transmission link, thus the HFF precoding problems are formulated as transmit power minimization (TPM) and max-min fair (MMF) received signal to interference plus noise ratio (SINR) problems, which can be transformed to indefinite quadratic optimization programs. Then this paper presents a semi-definite programming (SDP) algorithm to solve the problems for the IWSMSNs. The promising potential of HFF for the real IWSMSNs is demonstrated through simulations.

Convective cooling and heat partitioning to grinding chips in high speed grinding of a nickel based superalloy

Keli Peng,Pan Lu,Feihong Lin,Tan Jin,Wencheng Bao,Guizhi Xie,Zhentao Shang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

The level and variation of energy partition ratio to grinding chips in high speed grinding of a nickel based alloy has been investigated. The ratio to grinding chips is evaluated by relating the heat partitioning at the chip formation area with the whole thermal system, which is used to evaluate the convection heat transfer coefficient (CHTC) of water based grinding fluid. High level of CHTCs of the grinding fluid have been identified at high grinding speeds, beneficial heat transfer conditions of low ratios to the workpiece can be achieved. As the burnout happens with the CHTC dropping down to zero level, the ratio to the workpiece and grinding chips would become much higher, around 30-40 % of the grinding heat can be taken away by grinding chips. For nickel based superalloys, it is possible to achieve high material removal rates with the effective cooling of the grinding zone.

Soft-Decision for Differential Amplify-and-Forward over Time-Varying Relaying Channel

( Fengyue Gao ),( Lei Kong ),( Feihong Dong ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.3

Differential detection schemes do not require any channel estimation, which can be employed under user mobility with low computational complexity. In this work, a soft-input soft-output (SISO) differential detection algorithm is proposed for amplify-and-forward (AF) over time-varying relaying channels based cooperative communications system. Furthermore, maximum-likelihood (ML) detector for M-ary differential Phase-shift keying (DPSK) is derived to calculate a posteriori probabilities (APP) of information bits. In addition, when the SISO is exploited in conjunction with channel decoding, iterative detection and decoding approach by exchanging extrinsic information with outer code is obtained. Finally, simulation results show that the proposed non-coherent approach improves detection performance significantly. In particular, the system can obtain greater performance gain under fast-fading channels.

Research on Tolerance Design of 2K-V Reducer with Beveloid Gear Considering the Effect of Anti-Backlash

Zhiying Cui,Chaosheng Song,Feihong Zhu,Caichao Zhu 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.25 No.2

A mathematical model for calculating the lost motion of the 2K-V reducer with beveloid gear was established, considering the influence of assembly-induced error factors and the effect of backlash elimination. Sensitivity analysis was conducted on each error factor, and in combination with actual manufacturing processes, a set of tolerance correction values was designed using the Monte Carlo method. Based on these tolerance values, prototype manufacturing and performance testing were carried out. The validity of the proposed theoretical model was verified through experimental validation. The results indicate that three significant factors affecting the overall lost motion are the radial clearance of the tapered roller bearing, the backlash of the involute spline, and the radial runout of the small tooth difference gear. The tolerance correction reduced the difficulty of actual manufacturing, allowing the three highly sensitive error ranges to be relaxed to 757.58 times, 1.26 times, and 8.63 times of their original values, when the lost motion of the whole machine is less than 1arcmin.

Meticulous three-dimensional demarcation and separate presentation of statistically homogeneous structural domains within a large-scale jointed rock mass

Qingfa Chen,Tingchang Yin,Feihong Gao,Yuan Gao 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.1

Traditional methods used to demarcate homogeneous structural domains are mainly concerned with small-scale discontinuities; this approach can be regarded as a process for evaluating the degree of homogeneity among stochastic discontinuities from one site to another. This process forms the basis for determining the distribution of stochastic discontinuities within a homogeneous structural domain; however, it neglects large-scale discontinuities. In this study, the statistically homogeneous structural domains within a large-scale jointed rock mass were meticulously demarcated in three dimensions, which was performed in four steps. 1) A three-dimensional discontinuity network model was constructed containing both deterministic and stochastic discontinuities. 2) The model was subsequently discretized into a large number of cubic grids, and the MBi values of all the grids were calculated. 3) Using the K-means algorithm, the structural domain boundaries within the tested rock mass were meticulously demarcated, and a composited model consisting of homogeneous structural domains was constructed. 4) Each homogeneous structural domain was separately visualized. This demarcation method can consider large-scale discontinuities and improve the identification sensitivity in a large-scale jointed rock mass with a high accuracy. Moreover, the separate presentation of structural domains directly reflects the morphological properties unique to each structural domain.

A novel self-calibration method with POE-based model and distance error measurement for serial manipulators

Shenghai Hu,Manhui Zhang,Chao Zhou,Feihong Tian 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10

This paper proposes a novel self-calibration method to calibrate the accurate kinematic parameters of serial manipulators. First, a modified POE-based calibration model was established together with the modeling, identification and correction steps. It eliminates the joint offset errors and the dependent constrained parameters of joint screw errors in traditional POE-based models, which has completeness, continuity and minimality properties simultaneously and avoids normalization and orthogonalization operations. It also eliminates transformation errors of position detection information through adopting distance accuracy definition. Then, focusing on measurement step, the flowchart in a virtual closed-loop form is constructed with an infrared laser beam device and a simple observation surface. Meanwhile, the selection procedure for measurement configurations is figured out to determine the optimal number and the corresponding calibration set. Finally, experimental studies were conducted on a self-developed serial manipulator. The results of self-calibration experiments show that the proposed method is feasible and effective, and the distance accuracy could be improved by 73.64 % after performing optimal type. The results of comparison experiments with traditional external or self-calibration methods indicate that the proposed method could further improve convergence property and achievable accuracy of calibration effects, which also outperforms in terms of simplicity and accuracy.