Comparative Study of Nano-composite Ti(C,N)-based Cermets by Spark Plasma Sintering and Conventional Vaccum Sintering

Xiong Wei-Hao,Liang Zai-Guo,Lei Yan 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Tribological Properties of Ti(C,N)-based Cermet after Hot Isostatic Pressing at High Nitrogen Pressure

Xiong Wei-hao,Zheng Li-yun,Yan Xian-mei 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Sintered Ti(C,N)-based cermets were treated with hot isostatic pressing (HIP) at different nitrogen pressures. The tribological properties of the treated cermets have been evaluated. The results show that a hard near-surface area rich in TiN formed after HIP treatment. The cermets treated at higher pressure had a relatively lower friction coefficient and specific wear rate. In all cases the microhardness of treated cermets is higher than that without HIP natridation. The wear mechanisms of cermets were hard particle flaking-off and ploughing. It was also found that the HIP natridation is well-suited for improving the tribological properties of cermets.

Selective hydrogenation of benzene over Ru supported on surface modified TiO2

Fang Hao,Jingsong Zheng,Donghong Ouyang,Wei Xiong,Pingle Liu,Hean Luo 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.4

A series of catalysts with ruthenium nanoparticles (NPs) loaded on the binary oxide TS (TiO2-SiO2) support were prepared by facile sol-gel method for benzene selective hydrogenation. Different mole ratios of Ti/Si were investigated. The catalytic structure, composition, hydrophilicity, electronic state and acidity were characterized. The results indicate that the acidity of the samples increases gradually with the increase of the SiO2 amount. The dispersion of ruthenium nanoparticles was improved on binary oxide support compared with TiO2 and an obvious Ru size effect appeared with the increase of Ti/Si molar ratio. It was also found that the hydrophilicity of the supports could be efficiently improved by introducing a small amount of SiO2 to TiO2, which may be due to the large amount of surface hydroxyl groups on the binary oxide samples after SiO2 introduction. This result was consistent with the increasing trend of cyclohexene yield, indicating that the surface hydroxyl groups play a significant role in the motivation of cyclohexene desorption. Ru/TS (7 : 1) showed the best catalytic performance of 38.2% yield to cyclohexene with the highest initial selectivity to cyclohexene (S0) of 87.3%. The catalytic stability experiments showed that the yield of cyclohexene could maintain at 30% after five cycles.

Nitrogen-doped graphene loaded non-noble Co catalysts for liquid-phase cyclohexane oxidation with molecular oxygen

Fang Hao,Yuan Sun,Yidi Wang,Yang Lv,Pingle Liu,Xiong Wei,Hean Luo 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.8

Selective aerobic oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA oil) with high yield under mild and green conditions is still a significant challenge in the current chemical industry. Herein, nitrogen doped graphene loaded non-noble Co (Co-N-rGO) catalysts, prepared by a facile post-impregnation method, exhibited a high catalytic performance and stability in liquid phase cyclohexane oxidation with molecular oxygen. The experiment and characterization results show that N doping in the catalysts promotes Co metal particle dispersion and induces carbon film coating on Co to prevent leaching and agglomeration. Besides, density functional theory (DFT) calculations show that N doping is beneficial to the O-O bonds breaking in cyclohexyl-hydroperoxides (CHHP), thereby promoting the dissociation of CHHP and enhancing the yield to KA oil. In addition, the catalyst can be easily separated without appreciable loss of catalytic activity after recycling for five times, and show potential industrial application value for the catalytic oxidation of cyclohexane to KA oil in the chemical industry.

Direct Ink Writing of Mineral Materials: A review

Liang Hao,Danna Tang,Tao Sun,Wei Xiong,Zuying Feng,Ken E. Evans,Yan Li 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.2

Due to the intrinsically limited mechanical properties, functionalities and structures of mineral material composites (MMCs) made through traditional fabrication approaches, there is a critical need to develop novel three dimensional (3D) forming techniques that can construct mineral material composites (MMCs) and structures with high performance and functionalities. The direct ink writing (DIW), as a slurry deposition based additive manufacturing approach for MMCs, offers many advantages in terms of high precision, complex geometry, multi-material capability, cost effectiveness and environmental friendliness. This review gives a comprehensive overview on the state-of-art of DIW fabricated MMCs, including material classification, formulation and processing. It presents the key aspects of material processing and their effects on the properties and performance of DIW formed mineral materials. In addition, it illustrates the applications of DIW in the fields of architecture, tissue engineering, functional micro parts and geological engineering modelling.

A novel synthesis of carbon foam@Fe2O3 via hydrolysis‑driven emulsion polymerization for supercapacitor electrodes

Congxu Wu,Wei Xiong,Hao Li 한국탄소학회 2023 Carbon Letters Vol.33 No.7

Hierarchically porous carbon foam composites with highly dispersed Fe2O3 nanoparticles confined in the foam pores, facilely fabricated by hydrolysis-driven emulsion polymerization strategy. The as-generated acidic conditions of Fe3+ hydrolysis could catalyze the polymerization of phenolic resin, and the carbon-based composite materials containing iron oxides were obtained in situ. The structural characterization results show that HCF@Fe2O3 NPs-2 electrode has the largest specific surface area (549 m2/ g) and pore volume (0.46 cm3/ g). Electrochemical results indicates that typical HCF@Fe2O3 NPs-2 electrode displays good capacitive properties. including high specific capacitance (225 F/g at 0.2 A/g current density). Excellent magnification performance (capacity retention rate 80% as current density increases from 0.2 to 10 A/g). At the same time, HCF@SnO2 NPs was successfully synthesized by replacing hydrolyzed tin tetrachloride with ferric chloride. This study provides a new idea for the preparation of metal oxide–carbon matrix composites, and also highlights the potential of such carbon foams in application of energy storage.

Research on a Multi-Objective Control Strategy for Current-source PWM Rectifiers under Unbalanced and Harmonic Grid Voltage Conditions

Yi-Wen Geng,Hai-Wei Liu,Ren-Xiong Deng,Fang-Fang Tian,Hao-Feng Bai,Kai Wang 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

Unbalanced and distorted grid voltages cause the grid side current of a current source PWM rectifier to be heavily distorted. They can also cause the DC-link current to fluctuate with a huge amplitude. In order to enhance the performance of a current-source PWM rectifier under unbalanced and harmonic grid voltage conditions, a mathematical model of a current-source PWM rectifier is established and a flexible multi-objective control strategy is proposed to control the DC-link current and grid-current. The fundamental positive/negative sequence, 5th and 7th order harmonic components of the grid voltage are first separated with the proposed control strategy. The grid current reference are optimized based on three objectives: 1) sinusoidal and symmetrical grid current, 2) sinusoidal grid current and elimination of the DC-current 2nd order fluctuations, and 3) elimination of the DC-current 2nd and 6th order fluctuations. To avoid separation of the grid current components, a multi-frequency proportional-resonant controller is applied to control the fundamental positive/negative sequence, 5th and 7th order harmonic current. Finally, experimental results verify the effectiveness of proposed control strategy.

Research on a Multi-Objective Control Strategy for Current-source PWM Rectifiers under Unbalanced and Harmonic Grid Voltage Conditions

Geng, Yi-Wen,Liu, Hai-Wei,Deng, Ren-Xiong,Tian, Fang-Fang,Bai, Hao-Feng,Wang, Kai The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

Unbalanced and distorted grid voltages cause the grid side current of a current source PWM rectifier to be heavily distorted. They can also cause the DC-link current to fluctuate with a huge amplitude. In order to enhance the performance of a current-source PWM rectifier under unbalanced and harmonic grid voltage conditions, a mathematical model of a current-source PWM rectifier is established and a flexible multi-objective control strategy is proposed to control the DC-link current and grid-current. The fundamental positive/negative sequence, $5^{th}$ and $7^{th}$ order harmonic components of the grid voltage are first separated with the proposed control strategy. The grid current reference are optimized based on three objectives: 1) sinusoidal and symmetrical grid current, 2) sinusoidal grid current and elimination of the DC-current $2^{nd}$ order fluctuations, and 3) elimination of the DC-current $2^{nd}$ and $6^{th}$ order fluctuations. To avoid separation of the grid current components, a multi-frequency proportional-resonant controller is applied to control the fundamental positive/negative sequence, $5^{th}$ and $7^{th}$ order harmonic current. Finally, experimental results verify the effectiveness of proposed control strategy.

Momordicine I alleviates isoproterenol-induced cardiomyocyte hypertrophy through suppression of PLA2G6 and DGK-ζ

Hongming Li,Yumei Qiu,Mengdie Xie,Changsheng Ouyang,Xiaoyun Ding,Hao Zhang,Wei Dong,Yinhua Xiong,Xilan Tang 대한약리학회 2023 The Korean Journal of Physiology & Pharmacology Vol.27 No.1

This study aimed to observe the protective effect of momordicine I, a triterpenoid compound extracted from momordica charantia L., on isoproterenol (ISO)-induced hypertrophy in rat H9c2 cardiomyocytes and investigate its potential mechanism. Treatment with 10 μM ISO induced cardiomyocyte hypertrophy as evidenced by increased cell surface area and protein content as well as pronounced upregulation of fetal genes including atrial natriuretic peptide, β-myosin heavy chain, and α-skeletal actin; however, those responses were markedly attenuated by treatment with 12.5 μg/ml momordicine I. Transcriptome experiment results showed that there were 381 and 447 differentially expressed genes expressed in comparisons of model/control and momordicine I intervention/model, respectively. GO enrichment analysis suggested that the anti-cardiomyocyte hypertrophic effect of momordicine I may be mainly associated with the regulation of metabolic processes. Based on our transcriptome experiment results as well as literature reports, we selected glycerophospholipid metabolizing enzymes group VI phospholipase A2 (PLA2G6) and diacylglycerol kinase ζ (DGK-ζ) as targets to further explore the potential mechanism through which momordicine I inhibited ISO-induced cardiomyocyte hypertrophy. Our results demonstrated that momordicine I inhibited ISO-induced upregulations of mRNA levels and protein expressions of PLA2G6 and DGK-ζ. Collectively, momordicine I alleviated ISO-induced cardiomyocyte hypertrophy, which may be related to its inhibition of the expression of glycerophospholipid metabolizing enzymes PLA2G6 and DGK-ζ.

Drug-induced hyperglycaemia and diabetes: pharmacogenomics perspectives

Mou-Ze Liu,Hai-Yan He,Jian-Quan Luo,Fa-Zhong He,Zhang-Ren Chen,Yi-Ping Liu,Da-Xiong Xiang,Hong-Hao Zhou,Wei Zhang 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.7

Drug-induced diabetes is widely reported inclinical conditions, and it is becoming a global issuebecause of its potential to increase the risk of severe cardiovascularcomplications. However, which drug mechanismsexert their diabetogenic effects and why the effectspresent significant inter-individual differences remain largelyunknown. Pharmacogenomics, which is the study ofhow genomic variation influences drug responses, providesan explanation for individual differences in drug-induceddiabetes. We highlight that pharmacogenomics can beinvolved in regulating the expression of genes in signalingpathways related to the pharmacokinetics or pharmacodynamicsof drugs or the pathogenesis of diabetes, contributingto the differences in drug-induced glucoseimpairment. The pharmacogenomics studies of the majordiabetogenic drugs are reviewed, including calcineurininhibitors, antipsychotics, hormones, and antihypertensivedrugs. We intend to elucidate the genetic basis of druginduceddiabetes and pave the way for the precise use ofthese drugs in the clinic.