The Effect of H2O2/Fe2+ Catalytic Oxidation System on the Morphology, Structure and Properties of Flake-Like Poly(2,3-dimethylaniline)

Jun Yan,Li Ma,Mengyu Gan,Xiao Li,Zhitao Li,Jihai Tang,Ying Tu,Haifeng Hu 한국고분자학회 2014 Macromolecular Research Vol.22 No.8

In this work, flake-like poly(2,3-dimethylaniline) (P(2,3-DMA)) with enhanced thermal stability andanticorrosive ability was synthesized by in situ polymerization using H2O2/Fe2+ catalytic oxidation system, comparingwith traditional oxidant ammonium persulfate (APS) synthetic method. The structure and morphology of thesamples were characterized Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD) and field-emissionscanning electron microscope (FESEM). The experimental results demonstrated that using H2O2/Fe2+ catalytic oxidationsystem was more inclined to form the two-dimensional P(2,3-DMA) flakes. The enhancement in thermostabilityand corrosion resistance was attributed to the formation of phenazine-like structures in the polymer chains,which could serve as templates to form the flake-like morphology. In addition, using H2O2/Fe2+ catalytic oxidationsystem is more environmental friendly than the APS method that can avoid ammonium pollution on aquatic life aswell as waters.

Closed-Loop Bifurcation Analysis for a Novel Moving Mass Flight Vehicle

Zhitao Liu,Changsheng Gao,Jianqing Li,Wuxing Jing 한국항공우주학회 2018 International Journal of Aeronautical and Space Sc Vol.19 No.4

In this paper, nonlinear dynamics properties regarding a novel moving mass flight vehicle with large mass ratio are investigated based on bifurcation theory and continuation methods. Of particular interest is the impact of variation of command angle-of-attack and moving mass parameters on the controlled system. The nonlinear longitudinal dynamics model is established and the controller is designed using Immersion and Invariance method. Bifurcation analysis is conducted both from the prospective of static bifurcation and dynamical bifurcation, results of the closed-loop system are compared with the uncontrolled case. Numerical results obtained from bifurcation diagrams indicate that although the introduction of control system is capable of eliminating unstable regions caused by the variation of moving mass parameters, the change of command angle-of-attack still lead to Hopf bifurcation. Furthermore, analysis of limit cycle branch reveals the consecutive birth of Limit Point of Cycle bifurcation (LPC), then based on which a more detailed nonlinear dynamics process of the closed-loop system is analyzed.

Study on the activation mechanism of lead ions in the flotation of ilmenite using benzyl hydroxamic acid as collector

Qingyou Meng,Zhitao Yuan,Li Yu,Yuankai Xu,Yusheng Du 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.62 No.-

The activation mechanism of Pb2+ ions to ilmenite and the subsequent interaction with benzyl hydroxamic acid (BHA) were systematically investigated. The Pb2+ ions modification occurred via a chemical adsorption process, in which lead species interacted with iron hydroxyl compounds to form lead-containing complexes on the ilmenite surface. After lead ions activation, the surface of ilmenite became more active, and iron species and lead-containing complexes served as the main active sites to covalently bond with BHA in the form of metal-BHA chelate complexes. As a result, the BHA adsorption increased, giving rise to a concomitant increase in the floatability of ilmenite.

A Robust Approach for Overlay Text Localization and Extraction in Complex Video Scene

Jingfan Tang,Zhitao Li,Xingqi Wang,Ming Jiang,Ziyang Li 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.10

Overlay text in video carries important semantic clues for video information retrieval and summarization. In this paper, we propose a robust method that is able to accurately locate text lines and extract text even in complex video scene. In the text localization stage, this paper adopts the method based on corner point. First, corner detection is used to extract corners as text features from video frames. Then multi-layer filtering mechanism (MLFM) is used to locate the text lines, which consists of corners clustering, corners horizontal projection, background filtering and heuristic rules. This MLFM can effectively remove the isolated corners, locate the text lines accurately and remove the background or pseudo text lines automatically. In the text extraction stage, this paper proposed a twice binarization method that combines with polarity judgment on image. The polarity judgment was used as a guide to adjust the first binarization threshold when we perform the first binarization. After the first binarization, a main proportion of the image has been processed, and the rest will be processed by the second binarization. Experimental results show that this approach can fast and robustly locate text lines and extract text in video even under complex background.

Nanocomposites of Polypropylene and Halloysite Nanotubes Prepared by a Novel Vane Mixer

Xiaochun Yin,Sai Li,Liang Wang,Guangjian He,Zhitao Yang 한국고분자학회 2017 폴리머 Vol.41 No.2

Halloysite nanotubes (HNTs) were used to prepare polypropylene (PP) nanocomposites through a novel vane mixer. The effects of melt blend time and halloysite content on properties of composites were investigated. SEM analysis was performed to show that HNTs were well dispersed in PP matrix with the increase of mixing time. DSC showed both the degree of crystallinity and crystallization temperature increased due to the introduction of HNTs into PP, which indicating a potential nucleation effect induced by the nanotubes. TGA illustrated that the presence of HNTs had two opposite effects on the thermal behavior. A surface catalytic action of the halloysite speeded up thermal degradation of PP. However, this effect was reduced with improved HNTs dispersion. Rheological investigations revealed that rheological properties were significantly increased by the addition of low fraction of halloysite to PP. The 2 wt% HNTs nanocomposites reached maximum tensile strength because HNTs dispersed evenly in PP.

Comparison of the Safety and Effectiveness of Percutaneous Endoscopic Lumbar Discectomy for Treating Lumbar Disc Herniation Under Epidural Anesthesia and General Anesthesia

Zhiqiang Ren,Shenghua He,Jiao Li,Yeguang Wang,Juyi Lai,Zhitao Sun,Hualong Feng,Jian Wang 대한척추신경외과학회 2020 Neurospine Vol.17 No.1

Objective: To assess the safety and effectiveness of percutaneous endoscopic lumbar discectomy (PELD) under epidural anesthesia (EA) and general anesthesia (GA) for treating lumbar disc herniation (LDH). Methods: A retrospective study involving 86 patients with LDH managed by PELD under EA and GA was conducted from July 2018 to March 2019. These patients were divided into 2 groups according to the type of anesthesia. Patient’s demographics data as well as the operation time, complications, fluoroscopy shots, visual analog scale (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA), and MacNab scores of the 2 groups were recorded. All of the patients were followed-up at 6 months after operation. Results: There were no significant differences were detected in the preoperative demographics between the groups (p>0.05). Two cases (4.8%) under GA developed transient motor weakness, 3 cases (7.4%) presented numbness of lower limb, and 1 case (2.4%) had cauda equina syndrome after operation. In EA group, 1 case (2.2%) had motor weakness and 3 cases (6.7%) had lower limb numbness, which resolved completely at the last follow-up. There was significant difference between preoperative VAS, JOA, and ODI scores and postoperative scores (p<0.01). Moreover, there were no differences in the operation time, fluoroscopy shots, and MacNab scores between the 2 groups (p>0.05). Conclusion: EA and GA in PELD are effective and safe, and no significant difference in complications was observed. Based on our experience, we recommended junior surgeons to perform PELD under EA for getting feedback from the patient to avoid nerve injury and reduce the radiation dose. The concentration of ropivacaine in EA should be considered carefully.

Excessive retinoic acid inhibit mouse embryonic palate mesenchymal cell growth through involvement of Smad signaling

Zengli Yu,Xiaozhuan Liu,Zhan Gao,Zhitao Li,Jun Yin,Yuchang Tao,Lingling Cui,Zengli Yu 한국통합생물학회 2017 Animal cells and systems Vol.21 No.1

All-trans retinoic acid (atRA), the oxidative metabolite of retinoic acid (RA), is essential for palatogenesis. Overdose RA is capable of inducing cleft palate in mice and humans. Normal embryonic palatal mesenchymal (EPM) cell growth is crucial for shelf growth. Smad signaling is involved in many biological processes. However, it is not much clear if atRA could affect Smad signaling during EPM cells growth. In this study, the timed pregnant mice with maternal administration of 100 mg/kg body weight of RA by gastric intubation were cervical dislocation executed to evaluate growth changes of palatal shelves by hematoxylin and eosin (H&E) staining. At the same time, a primary mouse EPM (MEPM) cell culture model was also established. MEPM cells were treated with atRA (0.1, 0.5, 1, 5 and 10 μM) for 24, 48 and 72 h. The results indicated that the sizes of the shelves were smaller than those in control. AtRA inhibited MEPM cell growth with both increasing concentration and increasing incubation time, especially at 72 h in vitro. Moreover, atRA significantly increased the mRNA and protein expression levels of Smad7 (P < .05), but the mRNA and protein expression levels of PCNA were reduced (P < .05). We also found atRA inhibited phosphorylation of Smad2 compared with untreated group (P < .05). However, the protein and mRNA levels of Smad2 did not change both in atRA-treated and untreated group (P > .05). We demonstrated that RA induced inhibition of MEPM cell growth that could cause cleft palate partly by down-regulation of Smad pathway.

Experimental and Numerical Analysis of the Construction Process for the Oblique Cantilevered Steel Reinforced Concrete Structure

Qinglin Tao,Wanyun Yin,Rencai Jin,Feng Yu,Beng Niu,Yi Hu,Zhitao Li,Quanwei Liu,Yuandi Qian,Dongyun Jia 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.5

The oblique cantilevered steel reinforced concrete structure (OCSRCS) which includes members of oblique beam, upright column, and the oblique column is manly applied in Olympic Sports Center Stadium and has the characteristics of large section, long span, and large inclination angle. For the safe and economical construction of the OCSRCS, a new construction method named Self-balancing and Self-supporting Method is proposed to take place of traditional construction method of Full-space Support. In this method, cables are utilized to transfer the lateral pressure and gravity load of concrete in pouring to the embedded steel in the OCSRCS and the platform. For ensure the safety of this method, the fi nite element method is proposed to predict the mechanical behavior of the OCSRCS in construction, and the strain variation of the embedded steel in the OCSRCS during the construction process has also observed by the in-situ experiment. The stress distribution of steel and cables in the OCSRCS is investigated and validated in this paper. The results show that the Self-balancing and Self-supporting Method for the OCSRCS can eff ectively ensures the safety of the construction, and it provides references for the construction of large-scale OCSRCS in engineering.