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      • KCI등재

        Pd Nanoparticles Self-Assembled on Fluorine-Modified MWCNTs as Electro-Catalysts for Methanol Electro-Oxidation

        Xiao-Feng Zhang,Peng Dong,Ying-Jie Zhang,Xi-Kun Yang,Shu-Biao Xia,Zhen-Hua Jin,Ming-Li Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.3

        Multi-walled carbon nanotubes (MWCNTs) were modified by hydrogen fluoride (HF) in a simple method. With the help of fluorine, Pd nanoparticles (3.9 nm) synthesized by a one-step photochemical reduction were uniformly self-assembled on the active sites of functionalized MWCNTs and a new catalyst (Pd/HF-MWCNT) was obtained. UV–Vis absorption spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used. The results demonstrated that –F groups were introduced onto the surface of MWCNTs and C–F chemical bonds were formed. In addition, the electronic structure of Pd was changed. Pd–F coordination bond maybe formed between F atom and Pd atom. Cyclic voltammetry and chronoamperometry tests indicated that electrocatalytic activity of Pd/HF-MWCNTs catalyst for methanol in alkaline medium was about 1.6 times higher than that of the commercial Pd/C (JM) catalyst at the same condition. This new functionalized method has the advantages of simple step and safe operation. It is very significant to improve the wide application of MWCNTs and the commercial development of direct methanol fuel cells (DMFCs).

      • KCI등재

        Post-fire Study on Mechanical Properties of Damaged Ultra-high Strength Concrete

        Xiao Lyu,Guang-Hao Jia,Gan-Ping Shu,Xin Zhang,Er-Feng Du,Wen-Ming Wang 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.6

        In order to study the eff ect of steel tube, pre-load and temperature on residual performance of heated ultra-high strength concrete (UHSC), an experimental program was carried out to investigate the physical and mechanical properties of UHSC post-fi re in room temperature. With total of 54 standard cylindrical concrete specimens subjected to various temperatures ranging from 62 °C to 496 °C, their residual compressive strength, elastic modulus, peak strain was measured after natural cooling down. By comparing the test results of standard cylindrical concrete specimens with the results of the bare specimens in and after fi re, it is known that the residual compressive strength of standard cylindrical concrete specimens decayed more serious after exposing to same temperature. Seen from the results, the temperature which the specimens suff ered was found to be responsibility to the reduction of the compressive strength, elastic modulus, peak strain. As the temperature up to 300 °C, the strength reduction coeffi cient of UHSC was 0.67 ~ 0.68 and the elastic modulus reduction coeffi cient of UHSC was 0.41 ~ 0.51 with peak strain coeffi cient ε cr ( T ) /ε 0 1.57 ~ 1.67. Finally, based on the analysis of test results, simple formulae were proposed to describe the eff ect of temperature on residual performance of heated UHSC which infi lled the steel tube.

      • KCI등재

        Influence of Preparation Conditions on the Formation of Copper (II) Architectures with Pyrazine-2,3,5-tricarboxylic Acid

        Feng-Qin Wang,Shu Lin,Ming-Lin Guo,Jun-Jian Xu,Xiao-Qing Wang,Yong-Nan Zhao 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.7

        Three new metal-organic copper(II) complexes, [Cu(H_2PZTC)_2]_n·2nH_2O (1), [Cu(HPZTC)·2H_2O]_n·2nH_2O (2),and Cu_2[(PZHD)(OH)(H_2O)_2]_n (3) (H_3PZTC = pyrazine-2,3,5-tricarboxylic acid, PZHD^3− = 2-hydroxypyrazine-3,5-dicarboxylate), have been synthesized from Cu(II)/H3PZTC system under different synthetic conditions, and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis. In complexes 1 and 2, H_3PZTC ligands loose one and two protons, which were transformed into H_2PZTC− anion and HPZTC^2− dianion under different preparation condition, respectively. Furthermore, two ligands coordinate with Cu(II) cations in different modes, leading to the formation of the different chain structures. In complex 3, H_3PZTC ligand was converted into a new ligand-PZHD by in situ decarboxylation and hydroxylation under a higher pH value than that for complexes 1 and 2. PZHD ligands link the Cu(II) cations to form a 2D layer structure. These results demonstrate that the preparation conditions,including pH value and reaction temperature etc, play an important role in the construction of complexes based on H_3PZTC ligand.

      • KCI등재

        Enhancement clay tolerance of PCE by lignin-based polyoxyethylene ether in montmorillonite-contained paste

        Xiao-Kang Li,Da-Feng Zheng,Tao Zheng,Xu-Liang Lin,Hong-ming Lou,Xueqing Qiu 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.49 No.-

        The dispersion ability of polycarboxylate ether (PCE) in fresh concrete is much impeded by clayimpurities. To improve the dispersion of PCE in the clay-contained concrete, lignin-based polyoxy-ethylene ether (PEG-grafted-lignin) was synthesized through polyethylene glycol (PEG) grafted to kraftlignin (KL). The results showed that PEG-grafted-lignin increased thefluidity of MMT-contained cementpaste when combined with PCE. It improved the rheological properties of MMT-contained cement pasteby reducing the yield stress and the rheological behavior index. The adsorption of PEG-grafted-lignin onMMT was more quickly than KL and the equilibrium adsorption amount was 31.43 mg/g at an initialconcentration of 100 mg/L. XRD revealed that PEG-grafted-lignin had inserted into the interlayerstructure of MMT, while DLS disclosed the spatial effect of PEG-grafted-lignin was much stronger thanPCE. This study put forward a new method in the anti-sludge study of PCE.

      • KCI등재

        Taguchi Approach for Anti-heat Stress Prescription Compatibility in Mice Spleen Lymphocytes In Vitro

        Xiao-yu Zhu,Gui-lin Cheng,Feng-hua Liu,Jin Yu,Yu-jie Wang,Tong-quan Yu,Jian-qin Xu,Ming Wang 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.7

        Heat stress (HS) may induce immunosuppression as well as inhibit the proliferation of lymphocytes. This study evaluated the effects on immune function of our prescription on splenic lymphocytes under HS as well as its compatibility. The effects of four herbal extracts from Agastache rugosa, Atractylodes lancea, Cortex Phellodendri, and Gypsum Fibrosum on heat treated splenic lymphocytes were investigated and the compatibility of the prescription was also explored by using the Taguchi method. This study revealed changes in proliferation by traditional Chinese medicines of splenic lymphocytes after HS. Proliferation in the HS group was significantly lower than the control group. Under HS, the effects of higher concentrations of Agastache rugosa (100 and 200 μg/mL), Atractylodes lancea (100 and 200 μg/mL), Cortex Phellodendri (50 and 100 μg/mL) and Gypsum Fibrosum (100 and 200 μg/mL) caused a significant increase on ConA/LPS-induced proliferation of lymphocytes than lower concentrations. We, therefore, conclude that the prescription of traditional Chinese medicines may recover splenic lymphocytes from the immunosuppression induced by HS. The Taguchi design, which allows rapid and high efficiency for the selection of the best conditions for our prescription on HS-treated splenic lymphocytes, demonstrated that Agastache rugosa (200 μg/mL), Atractylodes lancea (200 μg/mL), Cortex Phellodendri (100 μg/mL) and Gypsum Fibrosum (100 μg/mL)were the optimal conditions for the prescription. The validation experiment confirmed that our composition in optimum extraction conditions enhanced effects on ConA or LPS-stimulated lymphocytes under HS. The results showed that the Taguchi optimization approach is a suitable method for optimization of the composition of prescription.

      • KCI등재

        Genetic characterization of bovine viral diarrhea virus strains in Beijing, China and innate immune responses of peripheral blood mononuclear cells in persistently infected dairy cattle

        Xiao Gang Weng,Quan Jiang Song,Qiong Wu,Ming Chao Liu,Meng Ling Wang,Jiu Feng Wang 대한수의학회 2015 Journal of Veterinary Science Vol.16 No.4

        To acquire epidemiological data on the bovine viral diarrhea virus (BVDV) and identify cattle persistently infected (PI) with this virus, 4,327 samples from Holstein dairy cows were screened over a four-year period in Beijing, China. Eighteen BVD viruses were isolated, 12 from PI cattle. Based on genetic analysis of their 5’-untranslated region (5’-UTR), the 18 isolates were assigned to subgenotype BVDV-1m, 1a, 1d, 1q, and 1b. To investigate the innate immune responses in the peripheral-blood mononuclear cells of PI cattle, the expression of Toll-like receptors (TLRs), RIG-I-like receptors, interferon-a (IFN-a), IFN-b, myxovirus (influenza virus) resistance 1 (MX1), and interferon stimulatory gene 15 (ISG15) was assessed by qPCR. When compared with healthy cattle, the expression of TLR-7, IFN-a, and IFN-b mRNA was downregulated, but the expression of MX1 and ISG-15 mRNA was upregulated in PI cattle. Immunoblotting analysis revealed that the expression of interferon regulatory factor 3 (IRF-3) and IRF-7 was lower in PI cattle than in healthy cattle. Thus, BVDV-1m and 1a are the predominant subgenotypes in the Beijing region, and the strains are highly divergent. Our findings also suggest that the TLR-7/IRF-7 signaling pathway plays a role in evasion of host restriction by BVDV.

      • KCI등재

        Proteomic Analysis of Salt Stress Responses in Rice Shoot

        Xiao-Juan Li,Ming-Feng Yang,Yi Zhu,Yu Liang,Shi-Hua Shen 한국식물학회 2011 Journal of Plant Biology Vol.54 No.6

        To gain a better understanding of the mechanism of rice (Oryza sativa L.) in response to salt stress, we performed a proteomics analysis of rice in response to 250 mM NaCl treatment using shoots of 3-day-old nascent seedlings. The changes of protein patterns were monitored with two-dimensional gel electrophoresis. Of 57 protein spots showing changes in abundance in response to salt stress, 52 were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The identified proteins were classified into eight functional categories. Several novel salt stress-responsive proteins, including protein synthesis inhibitor I, photosystem II stability/assembly factor HCF136, trigger factor-like protein and cycloartenol-C24-methyltransferase are upregulated upon salt stress. In order to figure out the different and similar molecular mechanism among salt and other stresses,regulation of some salt responsive proteins under other abiotic stress (cold and dehydration) and abscisic acid application was also analyzed. The possible molecular mechanism of rice seedlings in response to salinity and other stresses were discussed.

      • KCI등재

        A case study of teacher appraisal in Shanghai, China: in relation to teacher professional development

        Xiao Feng Zhang,Ho Ming Ng 서울대학교 교육연구소 2011 Asia Pacific Education Review Vol.12 No.4

        Literature has confirmed that teacher appraisal can and should facilitate the professional development of teachers. In the past, teacher appraisal in China has been conducted mainly for administrative purposes; nowadays, it is increasingly being viewed as a means of teacher professional development. However, the way in which teacher appraisal affects teacher professional development has not been fully recognized. This case study, of a junior secondary school in Shanghai, China, explores how teacher appraisal has been carried out and how teachers and administrators have perceived it in relation to teacher professional development. The research findings identify the mechanism by which the teacher appraisal system in question facilitates professional development. The system creates pressure and extrinsic incentives that 'push and pull' teachers to improve, and supports their growth through guidance and directions. In addition, environmental factors such as school culture contribute to the positive impacts that teacher appraisal has on professional development.

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