Extrusion of porous silicon nitride using different binders

Jian-Feng Yang,Guang-Peng Jiang,Ji-Qiang Gao 한양대학교 세라믹연구소 2010 Journal of Ceramic Processing Research Vol.11 No.1

Porous silicon nitride ceramics were prepared using an extrusion process. Starch and thermoset phenol-formaldehyde resin were used as binders. The effect of the different binders on the microstructure and mechanical strength of the porous silicon nitride were investigated in detail. It is shown that the microstructure was more uniform when phenol-formaldehyde resin was used as the binder. In contrast, the pore size distribution was bimodal when starch was used. Furthermore, the flexural strength of porous Si3N4 using resin as the binder was higher than that using the starch.

Grafting of A Novel Phosphorylcholine-Containing Vinyl Monomer onto Polycarbonateurethane Surfaces by Ultraviolet Radiation Grafting Polymerization

Jian Lu,Jintang Guo,Yakai Feng,Bin Gao 한국고분자학회 2012 Macromolecular Research Vol.20 No.7

An original phosphorylcholine (PC) containing vinyl monomer (compound 1) was grafted onto the surface of polycarbonate urethane (PCU) films by ultraviolet (UV) initiated polymerization. The vinyl monomer was synthesized from 2-hydroxyethyl methacrylate (HEMA), hexamethylene diisocyanate (HDI) and L-α-glycerylphosphorylcholine (GPC) by two relative reactions through the coupling of the isocyanate groups in HDI with the hydroxyl groups in HEMA and GPC, respectively. The existence of phosphorylcholine groups on the surface of compound 1-grafted PCU films was verified by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and water contact angle measurements. The surfaces of the grafted PCU films showed lower water contact angles than did the surfaces of non-grafted PCU films. Furthermore, the surface morphology of a grafted PCU film was observed using scanning electrical microscopy (SEM), which showed that the grafted polymer film exhibits a rough and pinhole-free surface. In addition, the blood compatibility of the compound 1-grafted PCU films was evaluated by platelet adhesion studies using the non-grafted PCU film as a reference. It was found by SEM that fewer platelets adhered to the surfaces of the grafted PCU films compared to the reference. The high PC-grafted PCU film did not show any substantial platelet attachment on its surface. These results indicated that these compound 1-grafted polymers may have potential application as biomaterials for vascular grafts and some subcutaneously implanted devices.

Soil and ribbed concrete slab interface modeling using large shear box and 3D FEM

Qian, Jian-Gu,Gao, Qian,Xue, Jian-feng,Chen, Hong-Wei,Huang, Mao-Song Techno-Press 2017 Geomechanics & engineering Vol.12 No.2

Cast in situ and grouted concrete helical piles with 150-200 mm diameter half cylindrical ribs have become an economical and effective choice in Shanghai, China for uplift piles in deep soft soils. Though this type of pile has been successful used in practice, the reinforcing mechanism and the contribution of the ribs to the total resistance is not clear, and there is no clear guideline for the design of such piles. To study the inclusion of ribs to the contribution of shear resistance, the shear behaviour between silty sand and concrete slabs with parallel ribs at different spacing and angles were tested in a large direct shear box ($600mm{\times}400mm{\times}200mm$). The front panels of the shear box are detachable to observe the soil deformation after the test. The tests were modelled with three-dimensional finite element method in ABAQUS. It was found that, passive zones can be developed ahead of the ribs to form undulated failure surfaces. The shear resistance and failure mode are affected by the ratio of rib spacing to rib diameter. Based on the shape and continuity of the failure zones at the interface, the failure modes at the interface can be classified as "punching", "local" or "general" shear failure respectively. With the inclusion of the ribs, the pull out resistance can increase up to 17%. The optimum rib spacing to rib diameter ratio was found to be around 7 based on the observed experimental results and the numerical modelling.

Mobile sand barriers for windblown sand mitigation: Effects of plane layout and included angle

Li Gao,Jian-jun Cheng,Bo-song Ding,Jia Lei,Yuan-feng An,Ben-teng Ma 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.34 No.3

Mobile sand barriers are a new type sand-retaining structure that can be moved and arranged according to the engineering demands of sand control. When only used for sand trapping, mobile sand barriers could be arranged in single row. For the dual purposes of sand trapping and sand stabilization, four rows of mobile sand barriers can be arranged in a staggered form. To reveal the effect of plane layout, the included angle between sand barrier direction and wind direction on the characteristics of flow fields and the sand control laws of mobile sand barriers, numerical computations and wind tunnel tests were conducted. The results showed that inflows deflected after passing through staggered arrangement sand barriers due to changes in included angle, and the sand barrier combination exerted successive wind resistance and group blocking effects. An analysis of wind resistance efficiency revealed that the effective protection length of staggered arrangement sand barriers approximately ranged from the sand barrier to 10H on the leeward side (H is sand barrier height), and that the effective protection length of single row sand barriers roughly ranged from 1H on the windward side to 20H on the leeward side. The distribution of sand deposit indicated that the sand interception increased with increasing included angle in staggered arrangement. The wind-breaking and sand-trapping effects were optimal when included angle between sand barrier direction and wind direction is 60°-90°.

Identification and Characterization of Gonatobotryum apiculatum Causing Leaf Spot and Blight on Sinowilsonia henryi

( Ying Gao ),( Hai Feng Liu ),( Zheng Xing Song ),( Xiao Ying Du ),( Jian Xin Deng ) 한국균학회 2020 Mycobiology Vol.48 No.1

Sinowilsonia henryi is a rare and endangered plant, as well as an endemic species in China. In July 2018, leaf spot and blight disease was observed on S. henryi in Yichang, Hubei, China. A fungus isolated from disease tissues was identified as Gonatobotryum apiculatum based on morphology and sequence analyses of ITS and LSU regions. Phylogenetic analyses indicated that the species belongs to Dothioraceae (Dothideales). Morphologically, the species produced two distinct types of conidia from authentic media, both conidia were described here. Pathogenicity tests showed that the fungus is a pathogen causing leaf spots on S. henryi. This is the first report of leaf spot and blight disease on S. henryi caused by G. apiculatum in China.

Biomimetic Surface Modification of Polycarbonateurethane Film via Phosphorylcholine-Graft for Resisting Platelet Adhesion

Wei Gao,Jintang Guo,Yakai Feng,Jian Lu,Musammir Khan 한국고분자학회 2012 Macromolecular Research Vol.20 No.10

Phosphorylcholine groups were covalently introduced onto a polycarbonateurethane (PCU) surface in order to create a biomimetic structure on the polymer surfaces. After introducing primary amine groups onto the polymer surface by 1,6-hexanediamine, phosphorylcholine groups were covalently linked onto the surface by the reductive amination between the amino group and the aldehyde group of phosphorylcholine glyceraldehyde (PCGA). The results of water contact angle test, X-ray photoelectron spectroscopy (XPS), and X-ray fluorescence spectrometer (XRF) analysis of the modified films indicated that PCGA had already been covalently linked to the PCU surface. The topographies and surface roughnesses were both imaged and measured by atomic force microscopy (AFM). Scanning electron microscopy (SEM)observation of the PCU films after treatment with platelet-rich plasma demonstrated that platelets had rarely adhered to the surface of the PCGA-grafted PCU films but had mainly adhered to the surface of the blank PCU films. The platelet adhesion result indicated that the PC modified PCU films could resist platelet adhesion after grafting with PCGA, and that these PCGA-grafted PCU materials, potentially, might be applied as blood-contacting materials.

Implications for new physics from ^B¯0→^π0^π0 and ^B¯0→^K¯0^K0

Cheng, Jian-Feng,Gao, Yuan-Ning,Huang, Chao-Shang,Wu, Xiao-Hong Elsevier 2006 Physics letters: B Vol.637 No.4

<P><B>Abstract</B></P><P>We have analyzed the <SUP>B¯0</SUP>→<SUP>π0</SUP><SUP>π0</SUP> puzzle in three kinds of models beyond the standard model (SM). It is shown that the minimal flavor violation (MFV) models, the minimal supersymmetric standard model (MSSM), and the two Higgs doublet models (2HDM) I and II cannot give an explanation of the <SUP>B¯0</SUP>→<SUP>π0</SUP><SUP>π0</SUP> puzzle within 1<I>σ</I> experimental bounds and the model III 2HDM can explain the puzzle without a conflict with other experimental measurements. If the constraint on <SUB>C8g</SUB> from b→sg is not imposed, for all kinds of insertions considered there are regions of parameter space, where the scalar quark mass is larger (much larger) than the gluino mass in the case of <I>LR</I> or <I>RL</I> (<I>LL</I> or <I>RR</I>), in which the puzzle can be resolved within 1<I>σ</I> experimental bounds.</P>

Ultrasensitive SERS-Based Immunoassay of Tumor Marker in Serum Using Au-Ag Alloy Nanoparticals and Ag/AgBr Hybrid Nanostructure

Yongfeng Gao,Yuanhui Feng,Lu Zhou,Lucia Petti,Zhe Wang,Jun Zhou,Shusen Xie,Jian Chen,Yanping Qing 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.1

Ultrasensitive detection of alpha-fetoprotein (AFP) is critical for the early diagnosis of liver cancer. In this work, a novel surface-enhanced Raman scattering (SERS)-based immunoassay complex has been successfully developed for the detection of AFP by using the Au-Ag alloy nanoparticals and the Ag/AgBr hybrid nanostructure. As the typical bimetal or metal/semiconductor plasmonic materials, besides the strong SERS enhancement characteristics, the Au-Ag alloy nanoparticals exhibit excellent monodispersity and the Ag/AgBr hybrid nanostructure demonstrates good stability. The experimental results show that the SERS-based immunoassay of AFP presents a low limit of detection of 1.86 fg/mL and a broad dynamic range from 2 fg/mL to 0.8 g/mL. Furthermore, the clinical applicability of the proposed SERS-based immunoassay has been assessed by the detection of AFP in the human serum samples of cancer patient and healthy person. The test data are consistent well with that of chemiluminescence immunoassay (CLIA) in the relative errors of –8.82–8.06% and show better detection sensitivity. It reveals that the proposed immunoassay protocol is significant for giving insight into the design of ultrasensitive biosensor and the point-of-care testing of cancers.

Dynamic Pricing Trading Market for Resources Sharing in IIU Federated Cloud

Tongrang Fan,Jian Liu,Feng Gao 보안공학연구지원센터(IJUNESST) 2013 International Journal of u- and e- Service, Scienc Vol.6 No.3

TEST SCENARIO DESIGN FOR INTELLIGENT DRIVING SYSTEM ENSURING COVERAGE AND EFFECTIVENESS

Qin Xia,Jianli Duan,Feng Gao,Qiuxia Hu,Yingdong He 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.4

Intelligent vehicle greatly benefits traffic safety, efficiency and driving comfortable. With the development of intelligent driving technology and its application, it is becoming increasingly important to do effective and comprehensive tests before putting on the market. Comprehensively considering the cost of test, an automatic generation method of test scenarios is proposed to ensure both coverage and effectiveness. Based on the analyzed key infuence factors of an intelligent driving system, the analytic hierarchy process (AHP) is used to determine their importance and accordingly an complex index is defined, based on which an improved test case generation algorithm based on the pairwise independent combinatorial testing tool (PICT) is proposed to ensuring both combinational coverage and complexity of test cases. Finally, the test scenario is generated by clustering these discrete test cases considering similarity and complexity. The high complex test cases are preferred to be combined together and conducted preferentially to increase the test efficiency. The effectiveness of this method is validated by applying it on a lane departure warning system (LDW).