Synthesis and Characterization of a Fluid-Like Novel Aniline Pentamer

Mengkui Wang,Jing Huang,Quanling Yang,Zhikang Liu,Lijie Dong,Shan Wang,Chuanxi Xiong 한국고분자학회 2018 Macromolecular Research Vol.26 No.3

A fluid-like novel aniline pentamer was synthesized by oxidative coupling and chemically doped with nonylphenol polyoxyethylene ether sulfate (NPES). The chemical structure, morphology, rheological behavior and conductivity of the assynthesized aniline pentamer were investigated. Unlike conventional aniline oligomers, this aniline pentamer exhibited a fluid-like behavior in the absence of any solvent at room temperature. Moreover, the aniline pentamer fluid showed liquid crystal characteristics. Combination of the fluid-like behavior, liquid crystal characteristics and good conductivity makes the aniline pentamer a promising environmentally friendly fluid for various applications such as field-effect transistors, liquid crystal devices, electrorheological materials, corrosion protection and other devices requiring electroactivity. This work provides a facile way to synthesizing flowable aniline oligomers with liquid crystal characteristics.

Research on Liquefaction Characteristics of SF6 Substitute Gases

Zhikang Yuan,Youping Tu,Cong Wang,Sichen Qin,Geng Chen 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

SF₆ has been widely used in high voltage power equipment, such as gas insulated switchgear (GIS) and gas insulated transmission line (GIL), because of its excellent insulation and arc extinguishing performance. However, SF₆ faces two environmental problems: greenhouse effect and high liquefaction temperature. Therefore, to find the SF₆ substitute gases has become a research hotspot in recent years. In this paper, the liquefaction characteristics of SF₆ substitute gases were studied. Peng–Robinson equation of state with the van der Waals mixing rule (PR-vdW model) was used to calculate the dew point temperature of the binary gas mixtures, with SF₆, C₃F₈, c-C₄F₈, CF₃I or C₄F₇N as the insulating gas and N₂ or CO₂ as the buffer gas. The sequence of the dew point temperatures of the binary gas mixtures under the same pressure and composition ratio was obtained. SF₆/N₂ < SF₆/CO₂ < C₃F₈/N₂ < C₃F₈/CO₂ < CF₃I/N₂ < CF₃I/CO₂ < c-C₄F₈/N₂ < C₄F₇N/N₂ < c-C₄F₈/CO₂ <C₄F₇N/CO₂. SF₆/N₂ gas mixture showed the best temperature adaptability and C₄F₇N/CO₂ gas mixture showed the worst temperature adaptability. Furthermore, the dew point temperatures of the SF₆ substitute gases at different pressures and the upper limits of the insulating gas mole fraction at -30℃, -20℃ and -10℃ were obtained. The results would supply sufficient data support for GIS/GIL operators and researchers.

Effect of Y₂O₃ addition on the microstructure and density of AgSnO₂ contact material

Xianhui Wang,Juntao Zou,Shuhua Liang,Zhikang Fan,Peng Xiao 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

AgSnO2-Y2O3 compound powders were prepared by a mechanical alloying (MA) method, AgSnO2-Y2O3 contact material was fabricated by pressing, sintering, repressing and resintering, the effect of Y2O3 addition, repressing and resintering on the microstructure and density of AgSnO2 contact material was investigated. The results show that there are drastic dedensifications or swelling, cracks and pores in AgSnO2 contact material fabricated by powder metallurgy, which thus has a lower density. The addition of Y2O3 is helpful in improving the microstructure and density significantly. The density increases significantly after repressing and resintering, and can reach 8.42 g/cm3. AgSnO2-Y2O3 compound powders were prepared by a mechanical alloying (MA) method, AgSnO2-Y2O3 contact material was fabricated by pressing, sintering, repressing and resintering, the effect of Y2O3 addition, repressing and resintering on the microstructure and density of AgSnO2 contact material was investigated. The results show that there are drastic dedensifications or swelling, cracks and pores in AgSnO2 contact material fabricated by powder metallurgy, which thus has a lower density. The addition of Y2O3 is helpful in improving the microstructure and density significantly. The density increases significantly after repressing and resintering, and can reach 8.42 g/cm3.

Research on Liquefaction Characteristics of SF6 Substitute Gases

Yuan, Zhikang,Tu, Youping,Wang, Cong,Qin, Sichen,Chen, Geng The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

$SF_6$ has been widely used in high voltage power equipment, such as gas insulated switchgear (GIS) and gas insulated transmission line (GIL), because of its excellent insulation and arc extinguishing performance. However, $SF_6$ faces two environmental problems: greenhouse effect and high liquefaction temperature. Therefore, to find the $SF_6$ substitute gases has become a research hotspot in recent years. In this paper, the liquefaction characteristics of $SF_6$ substitute gases were studied. Peng-Robinson equation of state with the van der Waals mixing rule (PR-vdW model) was used to calculate the dew point temperature of the binary gas mixtures, with $SF_6$, $C_3F_8$, $c-C_4F_8$, $CF_3I$ or $C_4F_7N$ as the insulating gas and $N_2$ or $CO_2$ as the buffer gas. The sequence of the dew point temperatures of the binary gas mixtures under the same pressure and composition ratio was obtained. $SF_6/N_2$ < $SF_6/CO_2$ < $C_3F_8/N_2$ < $C_3F_8/CO_2$ < $CF_3I/N_2$ < $CF_3I/CO_2$ < $c-C_4F_8/N_2$ < $C_4F_7N/N_2$ < $c-C_4F_8/CO_2$ < $C_4F_7N/CO_2$. $SF_6/N_2$ gas mixture showed the best temperature adaptability and $C_4F_7N/CO_2$ gas mixture showed the worst temperature adaptability. Furthermore, the dew point temperatures of the $SF_6$ substitute gases at different pressures and the upper limits of the insulating gas mole fraction at $-30^{\circ}C$, $-20^{\circ}C$ and $-10^{\circ}C$ were obtained. The results would supply sufficient data support for GIS/GIL operators and researchers.

Analysis of the Interference Effects in CMOS Image Sensors Caused by Strong Electromagnetic Pulses

Yang Zhikang,Wen Lin,Li Yudong,Zhou Dong,Wang Xin,Ding Rui,Zhong Meiqing,Meng Cui,Fang Wenxiao,Guo Qi 한국전자파학회 2024 Journal of Electromagnetic Engineering and Science Vol.24 No.2

With the electromagnetic environment becoming increasingly complex, it is crucial to address the risk posed by electromagnetic pulse, which critically impairs the performance and reliability of electronic systems based on complementary metal oxide semiconductor (CMOS) image sensors. In this context, research on the failure types of CMOS image sensors in a high-power electromagnetic environment, caused by strong electromagnetic pulses and the rapid evaluation method of interference immunity, has garnered significant interest. This paper conducts electromagnetic pulse simulation experiments on CMOS image sensors to first study their failure types, such as image abnormalities and functional interruption, and then identify the corresponding failure criteria. Furthermore, this study builds on the small sample test evaluation method to investigate the interference threshold of functional interruptions in CMOS image sensors by calculating the failure probability at different field strengths. The obtained data were combined with the Weibull distribution function for fitting, the results of which found the interference threshold to be at 40.4 kV/m. The findings of this study provide a basis for evaluating the survivability of CMOS image sensors and their associated reinforcement technology in high-power electromagnetic environments.

A drift-flux model for the analysis of low-velocity gas-lead-bismuth two-phase flow in a circular flow channel

Zihua Liu,Di Wang,Ren Liang,Dechang Cai,Yong Ouyang,Zhikang Lin 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.9

In this paper, a single-equation drift-flux type model for gas-lead-bismuth eutectic (LBE) two-phase flow analysis in the LBE fast reactor steam generator tube rupture (SGTR) accident is established. As the area-averaged superficial gas velocity increases, the calculated exponent P in the Bankoff model increases, and the distribution parameter C 0 decreases. The reliability of the model is confirmed by comparing the predicted results with a total of 76 sets of open experimental data from a bubble-column case and a gas lift pump case. The relative deviation between the predicted and experimental values of the void fraction is within 20 %. The model proposed in this paper helps to realize the early warning and analysis of SGTR accidents in LBE fast reactors, and can provide theoretical and technical guidance for the safety design and evaluation of LBE fast reactors.

Effect of Cold Metal Transfer Mix Synchro-Pulse Process on the Overall Morphology, Microstructure and Mechanical Properties of Wire+ Arc Additively Manufactured AA2219 Alloy

Xiaming Chen,Xiaonan Wang,Pengchen Huan,Zengrong Hu,Zhikang Wu,Bo Zhang,Hiromi Nagaumi 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

The difference in droplet transfer behavior between the traditional cold metal transfer plus pulse (CMT + P) process and thenew CMT mix synchro-pulse (CMT + SP) process, and its effect on the overall morphology, porosity, microstructure andmechanical properties of WAAM-ed AA2219 alloy are studied. Compared to the pulse stage (fP = 160 Hz) of the traditionalCMT + P process, the pulse stage of CMT + SP process consists of the low-frequency pulse and high-frequency pulse (HFP)stages. The high frequency (fH = 200 Hz) of the HFP stages formed a high arc force, enlarging the molten pool and enhancingthe convection of molten pool. This increased the melting depth between passes and facilitated the flow of the moltenpool to the sides and escaping of the pores. As a result, a highly symmetric WAAM-ed AA2219 alloy with a high effectiveheight (14.2 mm) and effective area (89.6 mm2),and low porosity (0.6 ± 0.2%) was manufactured by the CMT + SP process. Moreover, the fine grains (61 μm) with a 43% (area fraction) equiaxed grains were obtained with the CMT + SP process,leading to more θ′ phases precipitating. Thus, the average microhardness and tensile strength of the CMT + SP samplesincreased to 80.2 ± 6.7 HV and 265.0 ± 17.0 MPa, respectively.

Cone-beam computed tomographic evaluation of mandibular incisor alveolar bone changes for the intrusion arch technique: A retrospective cohort research

Lu Lin,Si Jiaping,Wang Zhikang,Chen Xiaoyan 대한치과교정학회 2024 대한치과교정학회지 Vol.54 No.2

Objective: Alveolar bone loss is a common adverse effect of intrusion treatment. Mandibular incisors are prone to dehiscence and fenestrations as they suffer from thinner alveolar bone thickness. Methods: Thirty skeletal class II patients treated with mandibular intrusion arch therapy were included in this study. Lateral cephalograms and cone-beam computed tomography images were taken before treatment (T1) and immediately after intrusion arch removal (T2) to evaluate the tooth displacement and the alveolar bone changes. Pearson’s and Spearman’s correlation was used to identify risk factors of alveolar bone loss during the intrusion treatment. Results: Deep overbite was successfully corrected (P < 0.05), accompanied by mandibular incisor proclination (P < 0.05). There were no statistically significant change in the true incisor intrusion (P > 0.05). The labial and lingual vertical alveolar bone levels showed a significant decrease (P < 0.05). The alveolar bone is thinning in the labial crestal area and lingual apical area (P < 0.05); accompanied by thickening in the labial apical area (P < 0.05). Proclined incisors, non-extraction treatment, and increased A point-nasion-B point (ANB) degree were positively correlated with alveolar bone loss. Conclusions: While the mandibular intrusion arch effectively corrected the deep overbite, it did cause some unwanted incisor labial tipping/flaring. During the intrusion treatment, the alveolar bone underwent corresponding changes, which was thinning in the labial crestal area and thickening in the labial apical area vice versa. And increased axis change of incisors, non-extraction treatment, and increased ANB were identified as risk factors for alveolar bone loss in patients with mandibular intrusion therapy.

Precise visualization and ROS-dependent photodynamic therapy of colorectal cancer with a novel mitochondrial viscosity photosensitive fluorescent probe

Runsha Xiao,Fan Zheng,Kuo Kang,Lei Xiao,Anyao Bi,Yiting Chen,Qi Zhou,Xueping Feng,Zhikang Chen,Hao Yin,Wei Wang,Zihua Chen,Xiaomiao Cheng,Wenbin Zeng 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Colorectal cancer (CRC) is a prominent global cancer with high mortality rates among human beings. Efficient diagnosis and treatment have always been a challenge for CRC management. Fluorescence guided cancer therapy, which combines diagnosis with therapy into one platform, has brought a new chance for achieving precise cancer theranostics. Among this, photosensitizers, applied in photodynamic therapy (PDT), given the integration of real-time imaging capacity and efficacious treatment feasibility, show great potential to serve as remarkable tools. Although much effort has been put into constructing photosensitizers for locating and destroying CRC cells, it is still in high need to develop novel photosensitizers to attain specific detection and fulfil effective therapy. Methods Probe HTI was rational synthesized for the diagnosis and treatment of CRC. Spectrometric determination was carried out first, followed by the 1O2 generation ability test. Then, HTI was displayed in distinguishing CRC cells from normal cells Further, the PDT effect of the photosensitizer was studied in vitro. Additionally, HTI was used in CRC BALB/c nude mice model to validate its viscosity labelling and tumor suppression characteristics. Results We successfully fabricated a mitochondrial targeting probe, HTI, together with remarkable viscosity sensitivity, ultralow background interference, and excellent 1O2 generation capacity. HTI was favorably applied to the viscosity detection, displaying a 11-fold fluorescent intensity enhancement in solvents from 1.57 cp to 2043 cp. Then, it was demonstrated that HTI could distinguish CRC cells from normal cells upon the difference in mitochondrial viscosity. Moreover, HTI was qualified for producing 1O2 with high efficiency in cells, supported by the sparkling signals of DCFH after incubation with HTI under light irradiation. More importantly, the viscosity labelling and tumor suppression performance in CRC CDX model was determined, enriching the multifunctional validation of HTI in vivo. Conclusions In this study, HTI was demonstrated to show a sensitive response to mitochondrial viscosity and possess a high 1O2 generation capacity. Both in vitro cell imaging and in vivo tumor treatment trials proved that HTI was effectively served as a robust scaffold for tumor labeling and CRC cells clearance. This breakthrough discovery held immense potential for advancing the early diagnosis and management of CRC through PDT. By leveraging HTI’s properties, medical professionals could benefit from improved diagnostic accuracy and targeted treatment in CRC management, ultimately leading to enhanced patient outcomes.