Preparation of PEO ceramic coating on Ti alloy and its high temperature oxidation resistance

Yongjun Xu,Zhongping Yao,Fangzhou Jia,Yunlong Wang,Zhaohua Jiang,Haitao Bu 한국물리학회 2010 Current Applied Physics Vol.10 No.2

Ceramic coatings were prepared in Na2SiO3–Na2CO3–NaOH system by pulsed bi-polar plasma electrolytic oxidation on Ti–6Al–4V alloy. The phase composition, structure and the elemental distribution of the coatings were studied by XRD, SEM and energy dispersive spectroscopy, respectively. The thermal shock resistance of the coated samples at 850 ℃ was evaluated by the thermal shock tests. The high temperature oxidation resistance of the coating samples at 500 ℃ was investigated. The results showed that the coating was mainly composed of rutile- and anatase TiO2, Increasing the concentration of Na2SiO3, TiO2content decreased gradually while the thickness of the coating increased. There were a large amount of micro pores and sintered particles on the surface of the coatings. Increasing concentration of Na2SiO3, the sintered particles on the surface turned large, and the Si content increased while the Ti content decreased gradually. When the concentration of Na2SiO3 was 15 g/L, the thermal shock resistance of the coatings was better than that of the coatings that prepared under other Na2SiO3 concentrations. The coating samples prepared under the optimized technique process based on the thermal shock tests improved the high temperature oxidation resistance at 500 ℃ greatly, whether considering the isothermal oxidation or the cyclic oxidation.

Ginseng-derived type I rhamnogalacturonan polysaccharide binds to galectin-8 and antagonizes its function

Yi Zheng,Yunlong Si,Xuejiao Xu,Hongming Gu,Zhen He,Zihan Zhao,Zhangkai Feng,Jiyong Su,Kevin H. Mayo,Yifa Zhou,Guihua Tai The Korean Society of Ginseng 2024 Journal of Ginseng Research Vol.48 No.2

Background: Panax ginseng Meyer polysaccharides exhibit various biological functions, like antagonizing galectin-3-mediated cell adhesion and migration. Galectin-8 (Gal-8), with its linker-joined N- and C-terminal carbohydrate recognition domains (CRDs), is also crucial to these biological processes, and thus plays a role in various pathological disorders. Yet the effect of ginseng-derived polysaccharides in modulating Gal-8 function has remained unclear. Methods: P. ginseng-derived pectin was chromatographically isolated and enzymatically digested to obtain a series of polysaccharides. Biolayer Interferometry (BLI) quantified their binding affinity to Gal-8, and their inhibitory effects on Gal-8 was assessed by hemagglutination, cell migration and T-cell apoptosis. Results: Our ginseng-derived pectin polysaccharides consist mostly of rhamnogalacturonan-I (RG-I) and homogalacturonan (HG). BLI shows that Gal-8 binding rests primarily in RG-I and its β-1,4-galactan side chains, with sub-micromolar K_D values. Both N- and C-terminal Gal-8 CRDs bind RG-I, with binding correlated with Gal-8-mediated function. Conclusion: P. ginseng RG-I pectin β-1,4-galactan side chains are crucial to binding Gal-8 and antagonizing its function. This study enhances our understanding of galectin-sugar interactions, information that may be used in the development of pharmaceutical agents targeting Gal-8.

Component Prototyping for the China Spallation Neutron Source Project

Jie Wei,Yanwei Chen,Yunlong Chi,Changdong Deng,Haiyi Dong,Shinian Fu,Wei He,Kaixi Huang,Wen Kang,Jian Li,Huafu Ouyang,Huamin Qu,Caitu Shi,Hong Sun,Jingyu Tang,Juzhou Tao,Sheng Wang,Zhongxiong Xu,Xueju 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.5

The China Spallation Neutron Source (CSNS) complex consists of an H- linear accelerator, a rapid cycling synchrotron accelerating the beam to 1.6 GeV, a solid tungsten target station and instruments for spallation neutron applications. The facility operates at a 25-Hz repetition rate with an initial design beam power of 120 kW and is upgradeable to 500 kW. The primary challenge is to build a robust and reliable user-friendly facility with upgrade potential at a fraction of the \world standard" cost. Success of the project relies on the results of prototyping research & development (R&D) of key technical systems and components. This paper discusses the prototyping experiences of the past two and a half years. The China Spallation Neutron Source (CSNS) complex consists of an H- linear accelerator, a rapid cycling synchrotron accelerating the beam to 1.6 GeV, a solid tungsten target station and instruments for spallation neutron applications. The facility operates at a 25-Hz repetition rate with an initial design beam power of 120 kW and is upgradeable to 500 kW. The primary challenge is to build a robust and reliable user-friendly facility with upgrade potential at a fraction of the \world standard" cost. Success of the project relies on the results of prototyping research & development (R&D) of key technical systems and components. This paper discusses the prototyping experiences of the past two and a half years.

The Constituents of Siegesbeckia orientalis

Xiong, Jiang,Ma, Yunbao,Xu, Yunlong The Korean Society of Pharmacognosy 1997 Natural Product Sciences Vol.3 No.1

Two new diterpenoids, orientalin A (1), and B (2), have been isolated together with six known compounds, kirenol (3), $ent-16{\beta},17-dihydroxykauran-19-oic$ acid (4), $ent-16{\beta},17-dihydroxykauran-19-oic$ $acid-16{\beta},l7-acetonide$ (5), $3,7-dimethylquercetin$ (6), ${\beta}-sitosterol$</YRC$ (7), and daucosterol (8) from the ethanol extract of Siegesbeckia orientalis (Compositae). Their chemical structures have been elucidated as $ent-15-acetoxy-2{\alpha},16,19-trihydroxypimar-8(14)-ene$ (1), $ent-16-acetoxy-2{\alpha},15,19-trihydroxypimar-8(14)-ene$ (2), respectively, on the basis of chemical and spectral evidence.

Shaking Table Tests and Numerical Analysis of the Interaction of a Base-isolated Steel Frame's Responses with a Long-span Roof

Tianyang Zhang,Haoru Guo,Yunlong Zhang,Shuguang Wang,Dong-sheng Du,Wei-zhi Xu 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.8

Seismic isolation technology has been extensively used in long-span spatial structures to alleviate losses caused by earthquake disasters. However, limited experimental studies have been conducted to examine the impact of horizontal and vertical vibrations in long-span roof structures with rubber bearings as isolation layers on the isolation effect. This paper presents a study that carried out shaking table experiments on 1/40 scale long-span steel frames, both with and without base isolation. It explores the interplay of horizontal and vertical vibrations in long-span roof structures equipped with rubber bearings, and its influence on the isolation effect. Three ground motions, including horizontal bidirectional (2D) and bidirectional-plus-vertical (3D) components were used as the seismic excitations. The whole structural dynamic responses of the base-isolation (BI) model and fixed-base (FB) model, the local responses of the grids and isolation bearings were measured. Under 2D seismic excitation, the grid layer in the FB model exhibits a substantial vertical acceleration response. When exposed to 3D seismic activity, the isolation system successfully delivers its expected isolation outcome. Although the isolation bearings could not attenuate the vertical seismic acceleration response induced by vertical ground motion, they effectively reduced the vertical dynamic response generated by the coupling by suppressing the horizontal seismic response.

Cloning and expression of a Chk1 gene in Daphnia pulex during different modes of reproduction

Xiaoge Guo,Shanliang Xu,Xuemei Yan,Wei Zhou,Xinyu Dai,Xiu Zou,Chunlin Wang,Danli Wang,Yunlong Zhao 한국유전학회 2015 Genes & Genomics Vol.37 No.9

The full-length cDNA of a Chk1 gene (DpChk1) was cloned from Daphnia pulex using RACE method. This cDNA is 1767 bp in length, consisting of a 1497 bp open reading frame encoding 498 amino acid protein. The deduced DpChk1 protein sequence contains phosphorylation sites, three conserved Ser-Gln and Thr- Gln motifs and shares 51–55 % similarity with A. pisum, M. rotundata, D. melanogaster, A. echinatior, B. terrestris, R. pulchellus and M. occidentalis, respectively. Gene expression analysis showed that Chk1 is differentially expressed in D. pulex during different reproductive modes. DpChk1 expression in sexually-reproducing females and males is significantly higher than in parthenogenetic Daphnia. Whole-mount in situ hybridization revealed that DpChk1 was expressed during two kinds of reproductive modes. In parthenogenetic females, hybridization signals were found in the antennae and thoracic limb, whereas expression levels in the corresponding sites of sexuallyreproducing females were relatively strong, DpChk1 could not be detected in the gonads of ephippial and parthenogenetic females. Taken together, these different reproductive stages and sex specific expression patterns are regulated temporally and spatially. We speculate that DpChk1 may be involved in conversion between different stages of reproduction and in sexual differentiation in D. pulex.

Recovery of [BMIM]FeCl4 from homogeneous mixture using a simple chemical method

Chongjun Zhao,Meng Wang,Bing Li,Xiuzhen Qian,Yunlong Xu,Guorong Chen 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.4

[BMIM]FeCl4 (1-butyl-3-methylimidazolium tetrachloroferrate) was successfully separated from a homogeneous mixture of [BMIM]FeCl4 and H2O via a simple two-step method of phase-division by adding inorganic salt plus chemical extraction, or alternatively, ultracentrifugation, or ultrastrong magnetic field. NaCl showed excellent and effective phase-dividing performance combined with chemical extraction method from the homogeneous mixture of [BMIM]FeCl4 and H2O lower to 1 v%.