Controlling spinning pitch property by tetrahydrofuran-soluble fraction of coal tar pitch co-carbonization with petrolatum

Jiang Wei,Ni Guosong,Zuo Pingping,Qu Shijie,Li Yunmei,Niu Hongxian,Shen Wenzhong 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Isotropic pitch-based carbon fiber was successfully prepared from tetrahydrofuran-soluble fraction of coal tar pitch co-carbonization with petrolatum by air-blowing. The effects of reaction temperature and time, amount of petrolatum added on the composition and spinning properties of resultant pitches were investigated. It indicated that petrolatum could effectively improve the softening point, aromaticity, hydrogen content and molecular weight of the resultant pitches by promoting cross-linking and dehydrogenation polymerization reactions at low air-blowing temperature. Moreover, more aliphatic and naphthenic structures had been introduced into resultant pitches as addition of petrolatum and also inhibited the generation of quinoline-insoluble particles. The obtained green fibers were facile to be stabilized and carbonized and the resultant carbon fibers showed fully isotropic and finer, uniform diameter with smooth surface and higher tensile strength of up to 0.92 GPa. It provided a facile chemical modification method for isotropic pitch-based carbon fiber production.

Fucosylated Chondroitin Sulfate from Sea Cucumber Inhibited Islets of Langerhans Apoptosis via Inactivation of the Mitochondrial Pathway in Insulin Resistant Mice

Wei Jiang,Shijie Li,Shiwei Hu,Jignfeng Wang,Wendong Song,Lili Ji,Yaning Wang 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.3

The effects of fucosylated chondroitin sulphate from sea cucumber (CHS) on inhibition of pancreatic islet apoptosis in high-fat high-sucrose diet (HFSD)-induced insulin resistant mice were studied for 19 weeks. CHS treatment significantly (p<0.05) decreased fasting blood glucose, insulin, and tumor necrosis factor (TNF)-α levels, and increased the serum adiponectin level, improved insulin resistance, and repaired HFSD-injured islets of langerhans, compared with controls. CHS supplementation significantly (p<0.05) inhibited pancreas cell apoptosis via reduction of cytochrome c, caspase 9, and caspase 3 mRNA expressions, cytochrome c release into the cytoplasm, and caspase 9 and cleaved-caspase 3 protein expressions, compared with controls. These effects were associated with upregulation of Bcl-2 and Bcl-xL mRNA and protein expressions, and downregulation of Bax and t-Bid mRNA and protein expressions. Combination treatments with CHS and rosiglitazone synergistically protected pancreatic islets. CHS improves insulin resistance and protects islets of langerhans from apoptosis via inactivation of the intrinsic mitochondrial pathway.

Controlling spinning pitch property by tetrahydrofuran‑soluble fraction of coal tar pitch co‑carbonization with petrolatum

Wei Jiang,Guosong Ni,Pingping Zuo,Shijie Qu,Yunmei Li,Hongxian Niu,Wenzhong Shen 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Isotropic pitch-based carbon fiber was successfully prepared from tetrahydrofuran-soluble fraction of coal tar pitch cocarbonization with petrolatum by air-blowing. The effects of reaction temperature and time, amount of petrolatum added on the composition and spinning properties of resultant pitches were investigated. It indicated that petrolatum could effectively improve the softening point, aromaticity, hydrogen content and molecular weight of the resultant pitches by promoting cross-linking and dehydrogenation polymerization reactions at low air-blowing temperature. Moreover, more aliphatic and naphthenic structures had been introduced into resultant pitches as addition of petrolatum and also inhibited the generation of quinoline-insoluble particles. The obtained green fibers were facile to be stabilized and carbonized and the resultant carbon fibers showed fully isotropic and finer, uniform diameter with smooth surface and higher tensile strength of up to 0.92 GPa. It provided a facile chemical modification method for isotropic pitch-based carbon fiber production.

Anti-glioma Effect and Safety of Docetaxel-loaded Nanoemulsion

Huil Gaoe,Xinguo Jiang,Zhiqing Pang,Shuaiqi Pan,Shijie Cao,Zhi Yang,Chen Chen 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.2

Docetaxel, an inhibitor of microtubule depolymerization, has been used for many malignancies. Due to its toxicity and the non-selective distribution of its commercial formulation, Taxotere®, new formulations with less toxicity and tumor targeting need to be explored. For its safety and ease of factory scale production, nanoemulsion, was selected to encapsulate docetaxel. The particle size of docetaxel loaded nanoemulsion (DNE) was 72.3 nm, the average zeta potential was −6.38 mV, the encapsulation efficiency was 93.1% and the drug loading capacity was 2.87%. Although DNE presented similar antiproliferation effects on both U87 cells and bEnd.3 cells, its in vivo toxicity was significantly lower than Taxotere®. In vivo fluorescent imaging suggested nanoemulsions loaded with a fluorescent probe could distribute to the brain and accumulate at the glioma site. The pharmacological experiments also confirmed that the DNE could target glioma sites and prolong the median survival time of mice with gliomas. In conclusion, DNE is a new, less toxic, drug formulation that is effective for brain glioma therapy.

Investigation on the stability of periodic motions of a flexible rotor-bearing system with two unbalanced disks

Chaofeng Li,Shihua Zhou,Shijie Jiang,Hexing Yu,Bang-chun Wen 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.7

The stability of periodic motion of a rotor-bearing system with two unbalanced disks is analyzed based on a multi-degree of freedom(M-DOF) finite element model. Nonlinear effects of supporting oil-film and inertia distributions as well as shearing effect are taken intoaccount. Focusing on the more realistic FE method to study the stability of nonlinear rotor-bearing system with the influence of the eccentricityphase, the stability calculation of the M-DOF FE model is done by using the combination of Shooting method and Newmarkmethod. Experiments with a rotor-bearing test rig (two disks on a shaft with two bearings) are then performed and results are presented. Itis found that typical instability characteristic is successfully produced. Through comparisons between calculated results and measurements,it is shown that the combination of Shooting method and Newmark method in studying the M-DOF rotor-bearing system is useful,especially for the complex rotor-bearing system. In addition, altering eccentricity phase of the two disks can significantly influence instabilitytype and speed. When the two disks are out of phase, the occurring of oil whip is restrained effectively. It is suggested that a carefulexamination should be made in modeling more complex non-linear rotor-bearing system.

Fucoidan from Acaudina molpadioides Protects Pancreatic Islet against Cell Apoptosis via Inhibition of Inflammation in Type 2 Diabetic Mice

Jinhui Wang,Shiwei Hu,Jingfeng Wang,Shijie Li,Wei Jiang 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.1

Inflammation induces pancreatic islet cell apoptosis. Effects of fucoidan from Acaudina molpadioides (Am-FUC) on inhibition of pancreatic islet cell apoptosis and inflammation in type 2 diabetic mice were investigated. Am-FUC repaired pancreatic islet cells, decreased serum C-reactive protein (CRP), macrophage inflammatory protein 1 (MIP-1), interleukin 1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) levels, and increased the IL-10 level. Am-FUC also reduced TNF-α, CRP, MIP-1, IL-1β, and IL-6 mRNA expressions, and increased IL-10 mRNA expression in epididymal adipose tissues. Am-FUC reduced Bid, Bax, cytochrome c, caspase 9, and caspase 3 mRNA expressions, and increased Bcl-2 and Bcl-xL mRNA expressions. Am-FUC down-regulated t-Bid, Bax, cytochrome c, and caspase 9 activities, cleaved caspase 3 proteins, and up-regulated Bcl-2 and Bcl-xL proteins. Thus, an Am-FUCblocked mitochondrial pathway was the suppression mechanism in pancreatic islet cell apoptosis via regulation of inflammatory cytokines providing dietary intervention in type 2 diabetes and inflammation-induced pancreatic islet apoptosis.

Iso-propanol assisted preparation of individualized functional palygorskite fibers and its impact on improving dispersion abilities in polymer nanocomposites

Lingli Ni,Pengyin Zhang,Jing Chen,Jinglong Jiang,Shijie Ding 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.6

Palygorskite (PAL) as a natural one-dimensional nanomaterial has attracted tremendous attention as reinforcement agent in polymer nanocomposites. But its intrinsic existing form of aggregates or bundles and hydrophilic properties, highly requires an eco-efficient and environmentally benign approach for both of the disaggregation and organo-modification of PAL. We report a facile and effective process to achieve individualized organo-modified PAL fibers. It was carried out through surface modification reactions in the form of PAL iso-propanol gels with various alkyl and functional silanes. In contrast to the modifications in highly toxic solvent of toluene, reactions in iso-propanol make it possible to modify the surface of individual PAL fibers to obtain isolated organo-modified PAL fibers. With such a relatively green procedure, even higher amount of organic substituent has been grafted on to the surface of PAL fibers. Consequently, excellent dispersion of modified PAL nanofibers in acrylate polymer coatings was achieved, which exhibits outstanding corrosion protection properties.

An Improved Mathematical Model for Estimating Polarization Parameters of Transformer Oil-Paper Insulation

Zhang Tao,Mandala Antonio Tome,Zuo Qian,Zhang Ning,Jiang Shijie 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

The parameters of dielectric response based on extended Debye circuit model can refl ect oil-paper insulation state. The model using the initial slop of recovery voltage to estimate circuit parameters, serve as good quality consistency with the measured data. However, the model can be applicable for large power transformers but not for distribution transformers. This paper proposed an improved mathematical model using recovery voltage peak, peak time and initial slope characteristics to solve dielectric response equivalent circuit parameters. The identifi cation of equivalent circuit parameters is converted into a mathematical optimization problem. And then particle swarm optimization algorithm is used for solving the problem. The improved mathematical model can decrease sampling data of recovery voltage. To check the validity of the estimated parameters, the on-site measured data of RVM experiments on actual transformers in various capacities is applied. The calculated result shows that the recovery voltage curve calculated and measured recovery voltage curve have good consistency, which can be advantageous to diagnose the oil-paper insulation status of transformer. It illustrates that the improved method proposed in this paper is feasible and eff ective.