Preparation, Structure, and Properties of Sn-Functionalized Star-Shaped Styrene-Isoprene-Butadiene Copolymer

Xin-he Kang,Shu-qin Liu,Lin Xu,Nini Wang 한국고분자학회 2018 Macromolecular Research Vol.26 No.10

A new kind of Sn-functionalized star-shaped styrene-isoprene-butadiene copolymer (Sn-SIBR) was synthesized using tin-containing organo-lithium (Sn-Li) as an initiator, tetrahydrofufury ethyl ether (ETE) and sodium dodecyl benzene sulfonate (SDBS) as polar modifiers by anionic polymerization. The kinetics of terpolymerization were studied, the microstructure, the glass transition temperature (T g), and molecular structure of Sn-SIBR were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC), respectively. The polymerization rate of the monomers and NMR results show that random Sn-SIBR are being produced in the presence of ETE and SDBS. NMR results also show that the mass fraction of Total1,2 (the sum of Bd1,2 and Ip1,2) unit and Ip3,4 unit and the T g of copolymers increase with the increase of ETE dosage or the decrease of polymerization temperature. However, the effects of SDBS dosage on them are not obvious. Mechanical and dynamic properties indicate that Sn-SIBR has a low rolling resistance and excellent wet skid resistance as well as good mechanical properties, and could satisfy the requirements of the rubber for high performance tire tread.

A Development of Miniaturized Piezoelectric Actuator System for Mobile Smart Structures

Kang, In Pil,Chae, Hyo Byung,Park, Ki Hoon,Yoon, Kwang Joon,Xin, Li Li,Kang, Tae Sam Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.326 No.-

<P>A smart material actuator is required for a smart structure having multifunctional performance. Among the smart material actuators, piezoelectric actuator is known for its excellent large force generation in broad bandwidth in a compact size. However it needs relatively large actuation voltage requiring a bulky hardware system. This study is mainly concerned to develop a self-powered miniaturized piezoelectric actuator driver (MIPAD) controlled by a radio controller for small sized piezoelectric smart structures. It can receive command from other microprocessors or a remote radio controller. We designed a real hardware and it demonstrated good performances even though the driving system was very small. The MIPAD is expected to minimize the weight and size of the piezoelectric actuator system and it can be easily embedded into mobile smart structures.</P>

A Portable Bender Element-Double Cone Penetration Testing Equipment for Measuring Stiffness and Shear Strength of In-Situ Soft Soil Deposits

Xin Kang,He-Mei Sun,Hong Luo,Tian Dai,Ren-Peng Chen 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.12

A portable bender element-double cone penetration (BE-DCP) testing equipment, which is invented as a prototype model for measuring the small-strain stiffness (shear wave velocity, Vs) and shear strength of in-situ soft soil deposits (loose sand and soft clay) is developed in this study. The shear wave velocity in two orthogonal directions (V s-hv and V s-hh) of the in-situ soils is measured from paired bender elements (BE) installed on the side of the cone shaft. The bender elements are housed in a mechanically controlled sliding block in the shaft which not only protects bender elements while the BE-DCP apparatus is being pushed into the ground, but also ensures a good contact between adjacent soil particles and benders when the target depth is reached. The real-time relationship of the pushing force and penetration depth is recorded by force transducer and laser displacement sensor and graphed in LabVIEW. Based on the cone penetration testing (CPT) theory, two formulas are derived to calculate the shear strength parameters of the in-situ soils. Test results obtained from both the portable bender element-double cone penetration (BE-DCP) testing apparatus and conventional laboratory experiments on Ottawa sand 20/30, four different sizes of Dolomite sands in various packing densities and Kaolinite under different water contents and densities as well as a field testing were compared and validated, indicating that the novel designed portable bender element-double cone penetration (BE-DCP) apparatus is robust, fast, and cost-efficient for measurement of small-strain stiffness and shear strength of in-situ soils.

Synthesis and High Expression of Chitin Deacetylase from Colletotrichum lindemuthianum in Pichia pastoris GS115

( Kang Li Xin ),( Xiao Mei Chen ),( Chao Zhai ),( Li Xin Ma ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.9

A gene, ClCDA, encoding chitin deacetylase from Colletotrichum lindemuthianum, was optimized according to the codon usage bias of Pichia pastoris and synthesized in vitro by overlap extension PCR. It was secretorily expressed in P. pastoris GS115 using the constitutive expression vector pHMB905A, The expression level reached the highest with 110 mg/l culture supernatant after 72 h of methanol induction, which comprised 77.27 U/mg chitin deacetylase activity, SDS-PAGE, mass spectrometry, and deglycosylation assays demonstrated that partial recombinant protein was glycosylated with an apparent molecular mass of 33kDa, The amino acid sequences of recombinant proteins were confirmed by mass spectrometry.

Examination of Interface Asperity and Particle Shape on the Mechanical Behavior of Soil-Structure Interfaces Using 3D Printed Models

Xin Kang,Hang Lei,Renpeng Chen 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.2

The influence of surface topography on the mechanical behavior of soil-structure interfaces over a range of particle sizes and shapes is systematically investigated in this research. 3D printed interfaces with different topographies and uniformly graded 3D printed soil particles and two types of natural sands (Ottawa sand 20/30 and Dolomite sand #1, #2 and #3) were employed and tested. Laboratory investigations showed that the shear strength and volume change responses of the 3D printed interfaces are positively influenced with the increase of the inclination of asperities. The proposed wedge friction model successfully explained the distinct mechanical behaviors of soil-structure interfaces under shearing. A "turning point" was found for the interface shear resistance with the increase of the inclination of asperities. When the surface topography produces passive resistance to the soil, the change of the surface topography has little effect on the interface mechanical behavior. The findings from this research will provide insights for soil-structure interface design and discrete element method (DEM) simulations in considering the mechanical behavior of soil-structure interfaces.

Coalescence behavior of aqueous drops in water-in-oil emulsions under high-frequency pulsed AC fields

Wanli Kang,Menglan Li,Hongbin Yang,Xin Kang,Fang Wang,Haizhuang Jiang,Min Zhang,Tongyu Zhu,Bauyrzhan Sarsenbekuly 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.93 No.-

High-frequency pulsed alternating currentfield (HFPACF) has attracted attentions owing to its excellentperformances of eliminating short circuit, saving energy and reducing environmental pollution. To studythe coalescence mechanism of aqueous drops in water-in-oil (W/O) emulsions under HFPACF, micro-behavior of dispersed drops for W/O emulsion was monitored by using a self-designed micro-visualmodel and coalescence mechanism was analyzed by discussing effects of pulse amplitude, pulsefrequency, pulse width ratio, demulsifier concentration, aqueous mass ratio of emulsion, and differentmodel oil emulsions. The results show that the dispersed drops coalesce under the action of electricfield,and the particle size of dispersed drops increases with the increase of pulse frequency and amplitude. When the pulse frequency or amplitude reach to a critical value, aqueous drops are driven to form waterstring or water channel between two electrodes which hinders further drops coalescence in other areas. However, with the increase of pulse width ratio, the size of dispersed drops increases slowly. Theoptimum pulse frequency and pulse amplitude are obtained at 3.9 kV and 4.21 kHz, respectively, theoptimal pulse width range is 54.9%-84.4%. When the concentration of demulsifier is 60 mg/L, thesynergistic demulsification effect achieves the highest performance. When the aqueous mass ratio ofemulsion reaches a high level (over 30%), which means the drops in emulsion have big size, thecoalescence performance under the same electricfield strength is great. Also, it is discovered that thedispersed drops in Yongping model oil emulsion have difficulty in forming water chains, since there aremuch asphaltenes and resins in the water-oil interface leading to high strength offilm. For Shuanghe oilemulsion drops are prevented from coalescing, because it contains a mass of paraffin, which can stabilizeemulsion at low temperature.

A Novel Non-phosgene Approach to the Synthesis of Methyl N-phenyl Carbamate by a Reaction of Methanol with Phenylurea

Wang, Xin-kui,Yan, Shi-run,Li, Zhen-hua,Fan, Kang-nian,Kang, Mao-qing,Peng, Shao-yi 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

A novel non-phosgene process for the synthesis of methyl N-phenyl carbamate (MPC) by a reaction of phenylurea with methanol was studied. The reaction between phenylurea and methanol was found to be a spontaneous reaction that took place in the absence of catalyst and gave MPC as the main product. Addition of a catalyst markedly influenced the reaction behavior. A basic catalyst greatly enhanced the yield of MPC, whereas an acidic catalyst promoted the formation of aniline and methyl carbamate. Moderate strength of basicity showed the best catalytic performance in the cases studied. The mechanism of reaction and catalyst functioning was discussed.

The NADPH oxidase AoNoxA in Arthrobotrys oligospora functions as an initial factor in the infection of Caenorhabditis elegans

Xin Li,Ying-Qian Kang,Yan-Lu Luo,Ke Qin Zhang,Cheng-Gang Zou,Lian-Ming Liang 한국미생물학회 2017 The journal of microbiology Vol.55 No.11

Reactive oxygen species (ROS) produced by NADPH oxidases can serve as signaling molecules to regulate a variety of physiological processes in multi-cellular organisms. In the nematophagous fungus Arthrobotrys oligospora, we found that ROS were produced during conidial germination, hyphal extension, and trap formation in the presence of nematodes. Generation of an AoNoxA knockout strain demonstrated the crucial role of NADPH oxidase in the production of ROS in A. oligospora, with trap formation impaired in the AoNoxA mutant, even in the presence of the nematode host. In addition, the expression of virulence factor serine protease P186 was up-regulated in the wild-type strain, but not in the mutant strain, in the presence of Caenorhabditis elegans. These results indicate that ROS derived from AoNoxA are essential for full virulence of A. oligospora in nematodes.

Effects of waste ground rubber tire powder (WGRT) and chemical blowing agent content on the cell morphology and physicomechanical properties of injection-molded polypropylene/WGRT foams

Xin, Zhen Xiang,Zhang, Zhen Xiu,Pal, Kaushik,Kang, Dong Jin,Lee, Sung Hyo,Kim, Jin Kuk Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of Vinyl and Additive Technology Vol.15 No.4

<P>Microcellular polypropylene (PP)/WGRT blends, a new outlet for the recycling of waste tire rubber, were prepared in an injection-molding process by using a chemical blowing agent. The effects of WGRT content and chemical blowing agent content on the density, cell morphology, and physicomechanical properties of the foamed PP/WGRT blends were investigated. The foam morphologies were characterized in terms of void fraction, average cell size, and cell density. The results indicated that both the WGRT and the blowing agent content had huge effects on the cell morphology and tensile properties of the PP/WGRT foams. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers</P>

Effect of teeth bending and mushrooming damages on leakage performance of a labyrinth seal

Xin Yan,Xinbo Dai,Kang Zhang,Jun Li,Kun He 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10

To achieve higher aerodynamic performance, turbine usually works at tight clearance, which results in inevitable rub between the rotor and stator parts of labyrinth seal due to vibrations, misalignment, mechanical force, thermal stress, etc. In the rubbing events, contact between labyrinth fin and rotor part will commonly induce the teeth bending and mushrooming damages, which significantly affect the discharge performance of a labyrinth seal. To account for the influence of teeth bending and mushrooming on leakage performance of a straight-through labyrinth seal, the leakage rates and flow fields in the worn labyrinth seal are measured and also compared with the original design cases. With numerical methods, the discharge behaviors of the labyrinth seal with different degrees of bending and mushroom damages are analyzed. It shows that the predicted leakage performance and flow fields in the labyrinth seals match well with the experimental tests. For the bending cases, the leakage rates and flow patterns in labyrinth seals are dependent on the effective clearance and bending angle. The leakage ratio of forward bending case is smaller than that of backward bending case with the same geometrical dimensions. However, for the mushroomed labyrinth seals, the leakage rates and flow patterns are much dependent on the effective clearance but slightly dependent on the mushroom radius.