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Performance evaluation and prediction of activated carbon for VOCs via experiments and LFER methods
Yufeng Zhao,Mengxi Zhang,Chen Yang,Ruyi Xiang,Xudong Yang,Longzhe Cui 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-
Due to the diversity and fluidity of volatile organic compounds (VOCs), it is difficult to conduct experimentalstudies on activated carbon (AC) used to capture VOCs in industry. Therefore, predicting theadsorption capacity of AC for VOCs is of great significance for evaluating the adsorption performanceof AC and developing its promising applications. Herein, based on the experimental data of dynamicadsorption, the poly parameter linear free energy relationship (pp-LFER) model was developed to quantifythe interactions between VOCs and AC. Through the dynamic adsorption curves of 25 VOCs on a fixedbed packed with the AC, the partition coefficient (PC) and adsorption capacity (q) of AC for VOCs werecalculated, and the pp-LFER equations used to predict them were established. For the PC values, thepp-LFER model consists of the excess molar refractive index (E), molar polarizability (S), hydrogenbondacidity (A), and logarithmic hexadecane-air partition coefficient (L), and the R2 of it was 0.86. Forthe ln q values, the developed model can predict it in R2 of 0.83, and the increased adsorption capacitywas predominantly attributed to the dispersive interaction (lL). Finally, the internal and external validationresults confirmed that the developed models have reliability, robustness, and predictability.
Yang Lu,Yi Lu,Yang Liu,Bo Hu,Yufeng Gong 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.6
A dynamics analysis of a novel parallel manipulator with one central rotational actuator and four translational actuators is conducted. A 3D model of the parallel manipulator is constructed and its characteristics and DoF are analyzed. The kinematics formulae are derived for solving the displacement, velocity and acceleration of the moving links. The dynamics formulae are derived for solving the inertial wrench of the moving links, the dynamic active forces along the active limbs, the dynamic active torque applied on a central active leg, and the dynamic constrained force exerted on the central active leg. A theoretical numerical example is given to solve the kinematics and dynamics solutions, and the theoretical solutions are verified by the simulation mechanism in Matlab. Finally, a reachable workspace of the novel parallel manipulator is constructed using CAD variation geometry.
Study on Preparation and Properties of PAI Materials Containing Trifluoromethyl in Side Chain
Haiyang Yang,Duxin Li,Jun Yang,Jin Wang,Shunchang Gan,Kaikai Cao,Yufeng Liu 한국고분자학회 2021 Macromolecular Research Vol.29 No.10
Polyamide-imide (PAI) materials with good heat resistance, excellent friction, wear properties, and low water absorption were prepared by acyl chloride process with diamine monomer containing trifluoromethyl in the side chain. The results showed that PAI prepared from 2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]- 4,4'-diamine without flexible hinge group had the best heat resistance, with T g as high as 302.6℃ and T d5% as 490.1℃. With the increase of the proportion of flexible hinge groups in diamine monomer, the thermal properties of PAI materials would decrease. The wear mechanism of PAI prepared from 2,2'-bis(trifluoromethyl)- [1,1'-biphenyl]-4,4'-diamine was mainly adhesive wear. With the increase of the proportion of flexible hinge groups in diamine monomer, the wear mechanism would change from abrasive wear, slight adhesive wear to severe adhesive wear. The friction coefficient and wear loss of PAI prepared by 1,4-bis(4-amino-2-trifluoromethylphenoxy) benzene were the smallest, which were 0.4706 and 3.5, respectively. PAI synthesized by diamine monomer containing trifluoromethyl had low water absorption and high water contact angle. With the increasing flexibility of monomer containing trifluoromethyl diamine, the elongation at break and tensile strength of the material increased gradually.
Security Authentication Method of Terminal Trusted Access in Smart Grid
Yufeng Wang,Lie Wu,Yun Yang 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.7
A security authentication method in smart grid terminal is proposed in this paper. This method layers the terminal authentication system structure of smart grid so as to improve the simplicity and extensibility on system deployment and realize flexible communication mechanism and the interaction mechanism among systems. This paper aims at preventing terminal information from being destroyed and achieving terminal verification integrity. Besides, this kind of authentication method has no special requirements for terminal users.
A 16 GHz 1-511 Broadband Programmable Frequency Divider
Yang Wang,Yi Zhang,Yufeng Guo 대한전자공학회 2023 Journal of semiconductor technology and science Vol.23 No.6
A high-speed broadband programmable frequency divider chip is designed and implemented in 0.18 μm SiGe BiCMOS process. The chip is based on the 2/3 dual-mode frequency divider, and integrates high-speed logic operation and reset control in the flip-flop to achieve a wide range of continuous integer frequency division ratio. Taking SCFL and CML DFF as basic units, it realizes wide-band operation and obtains a good input sensitivity range. The test results demonstrate that the operating frequency covers 0.1 GHz to 16 GHz. The frequency divider achieves 1-511 continuous frequency division. The output signal phase noise of the 1 GHz input is -153.7 dBc/Hz @ 100 kHz offset in divide-by-8 mode.
Improved Pupil-Size Diversity Technology for High-Resolution Imaging with Faint Objects
Xinxin Yang,Ge Ren,Haotong Ma,Qi Peng,Yufeng Tan,Jihong Wang 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.1
Phase aberration is one of the prime factors that degrade the quality of observed images. Pupil-size diversity technology (PSDT) is a newly developed post-processing method for aberration correction and image reconstruction. However, images reconstructed using PSDT suffer from massive grains when imaging astronomical faint objects, which extremely limits its further application. In this paper, we propose an improved PSDT with embedded denoising reprocessing to overcome this drawback. Diversity raw images, generated by modulating the size of the pupil, are firstly processed by blocking-matching and 3D filtering (BM3D), a state-of-art denoising algorithm. Then, the traditional PSDT can be employed to estimate the wavefront and reconstruct a high-resolution image. Both numerical simulations and experiment demonstrations show that our proposed strategy exhibits superior performance for aberrations correction and image restoration of faint objects in view of its efficiency and robustness. Being capable of realizing high-resolution imaging with faint objects, this proposed method may have important application prospects in the fields of astronomical object detection, remote sensing, \textit{etc.}
Mingquan Wang,Yufeng Wang,Yifei Zhang,Chunxia Li,Shichen Gong,Shuqin Yan,Guoliang Li,Guanghui Hu,Honglei Ren,Jianfei Yang,Tao Yu,Kejun Yang 한국유전학회 2019 Genes & Genomics Vol.41 No.7
Background Salt stress is a devastating environmental stress that causes plant growth inhibition and yield reduction. Objective The identification of salt-tolerant genes brings hope for the generation of salinity-tolerant crop plants through molecular breeding. Methods In this study, one salt-sensitive and one salt-tolerant maize inbred line were screened from 242 maize inbred lines. Reactive oxygen species (ROS)-related enzyme activities were detected and salt-responsive comparative transcriptome analysis was performed for control and 220 mM NaCl treated maize leaves. Results Salt-tolerant maize inbred line (L87) showed higher ROS-related enzyme (SOD, POD, APX and CAT) activities and accumulated relatively lower levels of ROS under salt stress. Of the total DEGs, 1856 upregulated DEGs were specific to L87, including stress tolerance-related members of the 70kDa family of heat shock proteins (Hsp70s) and aquaporins. The DEGs involved in the abscisic acid (ABA), ethylene, jasmonic acid (JA) and salicylic acid (SA) signal transduction pathways may determine the difference in salt tolerance between the two varieties, especially one central component SnRK2, that positively regulates ABA signaling and was only upregulated in L87. Analysis of DEGs related to ROS scavenging showed that some peroxidase (POD), glutathione S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) genes specific to L87 probably enhanced its salt tolerance. The analysis of differentially expressed transcription factors (TFs) suggested that WRKY TFs could contribute to the difference in salt tolerance between the two maize lines. Conclusion Compared with Salt-sensitive maize inbred line (L29), L87 exhibits specific regulatory mechanisms related to salt tolerance, including plant hormone interactions, ROS scavenging and the regulation of TFs. Our study identifies new candidate genes that may regulate maize tolerance to salt stress and provides useful information for breeding maize with high salt resistance.
Shougang Duan,Yufeng Yang,Yong Dong,Yu Wang,Beibei Jiang,Chuanqiang Li,Zhengrong Zhang 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.6
Ultra-fine grain AlCrFe2Ni2Wx(x = 0.1, 0.2, 0.3, 0.4) alloys were designed and prepared by vacuum arc melting, and correspondingmicrostructural evolution and mechanical properties were investigated. All of the alloys show a mixed structurewith FCC + BCC (B2) + TCP phases. The addition of W element has a significant effect on the formation mechanism of themorphology, which promotes the transition from FCC phase to μ phase and inhibits the spinodal decomposition of BCCphase. With the increase of W content, more μ phase precipitates from the FCC phase and grain boundaries. After the dissolutionof W element into matrix, the formed oversaturated solid solution and precipitated μ phase have the effect of solidsolution strengthening and second phase strengthening, respectively. The yield strength and Vickers hardness increasesfrom 765 to 1319.6 MPa and HV 332.2 to HV 461.8, respectively. The addition of W element enhances the strength of thealloys but reduced ductility. The AlCrFe2Ni2W0.1alloy exhibits outstanding comprehensive mechanical properties, with itsfracture strength reaching 2726.5 MPa and a considerable compressive strain of 43.3%, which implies promising potentialengineering application.