Highly Efficient Microwave-assisted Aminolysis of Epoxides in Water

Zuo, Hua,Li, Zhu-Bo,Zhao, Bao-Xiang,Miao, Jun-Ying,Meng, Li-Juan,Jang, Ki-Wan,Ahn, Chul-Jin,Lee, Dong-Ha,Shin, Dong-Soo Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.suppl8

Highly efficient and rapid aminolysis of epoxides with various amines in water under microwave irradiation in the absence of catalyst was developed. Chiral ${\beta}$-amino alcohols were formed in a short time with excellent yields.

Structure and electrical properties of Pr6O11-doped CaCu3Ti4O12 NTC ceramics

Zuo Yang,Tian Jian,Tian Yuxin,Miao Guangtan,Fu Peng 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.3

The xPr6O11–(1 − x)CaCu3Ti4O12 (CCTO) ceramics with perovskite structure were prepared by the solid-state reaction method. The effects of Pr 6O11 addition on the microstructure and electrical properties of the CCTO ceramics were studied. The addition of Pr 6O11 promoted the sintering of CCTO ceramics, and the mean grain sizes increased gradually from 2.13 to 5.08 μm with increasing Pr 6O11 content. All the samples had noticeable negative temperature coefficient (NTC) effect, and both the grain and grain boundary effects contributed to their NTC characteristics. The thermistor characteristic parameter B25/75 decreased from 6883 to 5291 K as Pr 6O11 contents increased from 0.00 to 0.08. The analysis shows that the conductivity of Pr 6O11–CCTO ceramics arises mainly from the electron hopping transport mechanism. The GB resistances are noticeably higher than grain resistances at the same Pr 6O11 content. All the samples showed electrical relaxation behavior. The above observations indicate that the structures and electrical properties of CCTO ceramics can be attuned precisely by adjusting the Pr 6O11 concentration.

Highly Efficient Microwave-assisted Aminolysis of Epoxides in Water

Hua Zuo,Zhu-Bo Li,Bao-Xiang Zhao,Jun-Ying Miao,Li-juan Meng,Kiwan Jang,안철진,Dong-Ha Lee,신동수 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.8

Highly efficient and rapid aminolysis of epoxides with various amines in water under microwave irradiation in the absence of catalyst was developed. Chiral β-amino alcohols were formed in a short time with excellent yields.

An Improved CPTu-based Method to Estimate Jacked Pile Bearing Capacity and Its Reliability Assessment

Yong-hong Miao,Ping-ping Zuo,Jie Yin,Shoaib Ahmed,Guo-long Bai,Jian-fei Lu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.9

This paper presents an improved method for predicting the bearing capacity of single jacked pile based on piezocone penetration test (CPTu) data which contain tip resistance (qt), side friction ( fs) and excess dynamic pore water pressure (u2). Firstly, the average value of qt was determined to calculate the pile unit base resistance according to the influence zone of the logarithmic spiral concerning the effect of soil types. Secondly, fs and u2 were used to calculate the pile unit shaft resistance considering the effect of friction fatigue. The pile jacking force was obtained in terms of unit base resistance and unit shaft resistance. The ultimate bearing capacity was finally determined using pile jacking force multiplied by a force ratio denoted as Rf. The ultimate bearing capacities calculated for two case projects show a good agreement with the measured results, which indicates that the proposed method is feasible and effective. Reliability assessment was carried out on the proposed method and other five estimation methods with respect to the reliability index obtained by advanced first-order second-moment (AFOSM) method. Comparison result showed that the method proposed in this study has a higher reliability index over other five existing methods. Therefore, the proposed method can be used as a reliable alternative to predict the bearing capacity in the engineering practice of jacked pile foundation.

Selective oxidation of 5-formyloxymethylfurfural to 2, 5-furandicarboxylic acid with Ru/C in water solution

Zhihao Si,Xin Zhang,Miao Zuo,Tao Wang,Yong Sun,Xing Tang,Xianhai Zeng,Lu Lin 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.2

2, 5-furandicarboxylic acid (FDCA) is a one of the most promising biomass-derived chemicals to substitute the non-renewable terephthalic acid as the monomer for producing polyethyleneterephthalate. At present, the oxidation of HMF is regarded as a prevalent way to prepare FDCA. Nevertheless, the isolation and storage of HMF is still a challenge. Herein, based on the higher stability of 5-formyloxymethylfurfural (FMF) than 5-hydroxymethylfurfural (HMF), we present an effective preparation route to prepare FDCA by substituting HMF with FMF as feedstock. A complete conversion of FMF and a 93.55% selectivity of FDCA were obtained in the mixed solvent of water and 1, 2- dioxane using Ru/C as catalyst and O2 as oxidant. An improved process was developed for preparing FDCA using FMF as feedstock. The investigation of conversion pathway showed that FMF and HMF were simultaneously oxidized to 2, 5-diformylfuran (DFF) in a case of the existence of the reversible equilibrium between FMF and HMF. Then DFF was oxidized to 5-formyl-2-furancarboxylic acid (FFCA). Subsequently, FFCA was oxidized to FDCA. In this process, the oxidation of FFCA to FDCA was determined as the rate-determining step. Furthermore, appropriate alkalinity favored the selectivity of FDCA and the conversion of FMF.

Analysis of Magnetic Particle Agglomeration Structure and Interaction Forces Between Magnetic Particles

Jia Long,Zixu Miao,Huihuang Chen,Rongdong Deng,Weiran Zuo,Bao Guo,Jiangang Ku 한국자기학회 2020 Journal of Magnetics Vol.25 No.1

Chain-like and diamond-shaped magnetic particle agglomeration (MPA) commonly forming in a weak magnetic field are simulated based on the finite element method (FEM), and the effects of particle diameter, magnetic field strength, particle relative magnetic permeability, and particle number in magnetic particle chains (MPCs) and diamond-shaped MPA on the strength of MPA are analysed in detail. The results show that magnetic forces on the centre contact points (CCPs) of MPA are positively correlated with the particle diameter, magnetic field strength, particle relative magnetic permeability, and particle number. In addition, the forces on the CCPs of the MPCs (N=2) have a square relationship with the particle diameter and magnetic field strength and have a power relationship of 1.25 with the particle relative magnetic permeability. The forces on each contact point decrease slowly from the centre to both ends in the MPCs and then rapidly decrease to one value (approximately 0.779 times the forces on the CCPs). As for the diamond-shaped MPA, with the increase in the angle α between the magnetic field and axis of diamond-shaped MPA, the force magnitude of the particle entrained parallelly in the diamond-shaped MPA shows a trend of a “cosine curve” shape and the minimum value is 2109 times that of the entrained particle’s gravity. The angle θ between the direction of the force and the negative X-axis shows a trend of a “sine curve” shape. When α = 25° and 155°, the angle θ of the force on the entrained particle reaches an extreme value, that is, θ = 21.87°. Only if the angle θ reaches 30º can the particle entrained parallelly escape from the diamond-shaped MPA. Thus, the diamond-shaped MPA remains in a stable state and it is difficult to disperse MPA by changing the direction of the magnetic field.

TGF-β1/IL-11/MEK/ERK signaling mediates senescence-associated pulmonary fibrosis in a stress-induced premature senescence model of Bmi-1 deficiency

Haiyun Chen,Jialong Liang,Xin Gu,Jiawen Zhou,Chunfeng Xie,Xianhui Lv,Rong Wang,Qing Liu,Zhiyuan Mao,Haijian Sun,Guoping Zuo,Dengshun Miao,Jianliang Jin 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

To study whether TGF-β1/IL-11/MEK/ERK (TIME) signaling mediates senescence-associated pulmonary fibrosis (SAPF) in Bmi-1-deficient (Bmi-1−/−) mice and determines the major downstream mediator of Bmi-1 and crosstalk between p16INK4a and reactive oxygen species that regulates SAPF, phenotypes were compared among 7-week-old p16INK4a and Bmi-1 double-knockout, N-acetylcysteine (NAC)-treated Bmi-1−/−, Bmi-1−/−, and wild-type mice. Pulmonary fibroblasts and alveolar type II epithelial (AT2) cells were used for experiments. Human pulmonary tissues were tested for type Ι collagen, α-smooth muscle actin (α-SMA), p16INK4a, p53, p21, and TIME signaling by using enzyme-linked immunosorbent assay (ELISA). Our results demonstrated that Bmi-1 deficiency resulted in a shortened lifespan, ventilatory resistance, poor ventilatory compliance, and SAPF, including cell senescence, DNA damage, a senescence-associated secretory phenotype and collagen overdeposition that was mediated by the upregulation of TIME signaling. The signaling stimulated cell senescence, senescence-related secretion of TGF-β1 and IL-11 and production of collagen 1 by pulmonary fibroblasts and the epithelial-to-mesenchymal transition of AT2 cells. These processes were inhibited by anti-IL-11 or the MEK inhibitor PD98059. NAC treatment prolonged the lifespan and ameliorated pulmonary dysfunction and SAPF by downregulating TIME signaling more than p16INK4a deletion by inhibiting oxidative stress and DNA damage and promoting ubiquitinproteasome degradation of p16INK4a and p53. Cytoplasmic p16INK4a accumulation upregulated MEK/ERK signaling by inhibiting the translocation of pERK1/2 (Thr202/Tyr204) from the cytoplasm to the nucleus in senescent fibroblasts. The accumulation of collagen 1 and α-SMA in human lungs accompanied by cell senescence may be mediated by TIME signaling. Thus, this signaling in aging fibroblasts or AT2 cells could be a therapeutic target for preventing SAPF.