Investigation on Air Texturing Process for Diacetate Blending with Polyester Filaments

Zhang, Jing,Zhang, Zhilong,Wang, Shanyuan,Qin, Xiaohong The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.4

Influences of processing parameters on tensile property, stability and bulk of core-and-effect air textured yarns of diacetate polyester filaments are mainly examined in this paper. When the air pressure is raised, the tenacity and breaking elongation of textured yarns are reduced, Instability I and II tend to decrease at first and then increase, the core bulk declines markedly at first and then changes slowly, whereas the overall bulk changes little at first and then goes up greatly. With increase in texturing speed, the yarn tenacity and breaking elongation both drop initially then begin to increase, the core bulk and overall bulk are almost linearly increased, while the yarn instability changes with an unclear trend. When the winding underfeed ratio is increased, the yarn tenacity, breaking elongation and core bulk are reduced, but the yarn stability is slightly improved. The wetting of the core component produces higher tenacity, breaking elongation, instability and bulk, compared with that of the effect component or that of both, but the difference is insignificant.

THE ROLE OF T(X) IN THE IDEAL THEORY OF BCI-ALGEBRAS

Xiaohong Zhang,Jun, Young Bae 대한수학회 1997 대한수학회보 Vol.34 No.2

Properties of Core-and-effect Air Textured Yarns Blended by Diacetate and Polyester Filaments

Zhang, Jing,Zhang, Zhilong,Wang, Shanyuan,Qing, Xiaohong The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.1

In present work, PET FDY has been used to blend with diacetate filaments by air texturing process and core-and-effect air-textured yarns have been produced. The influences of both over-feeds of core and effect components on properties of textured yarns were mainly examined. It was observed that a spun-like effect of diacetate filaments occurred during air texturing and there were a little amount of free fiber ends besides loops on blended air textured yarns, while the number of free fiber ends changed little with variation in over-feeds. The tenacity of textured yarns decreased with increase in over-feeds of effect or core component. The breaking elongation increased with increase in over-feed of effect component, but decreased with increase in over-feed of core component. The yarn stability improves when both over-feeds are increased. The effect of over-feeds on boiling water shrinkage shows no clear trend. The core and average diameters are higher at high over-feed of effect component, but the over-feed of core component exhibits little effect on yarn diameters. The number and size of loops re increase with increased over-feed of effect component.

Adaptive Synchronization for a Class of Fractional Order Time-delay Uncertain Chaotic Systems via Fuzzy Fractional Order Neural Network

Xingpeng Zhang,Xiaohong Zhang,Dong Li,Dan Yang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.5

Uncertainty and delay are common phenomena in chaotic systems, but their existence will increase thedifficulty of synchronization. For the sake of actualizing synchronization of fractional order time-delay uncertainchaotic systems, we propose an adaptive fractional order fuzzy neural network synchronization scheme based onthe linear matrix inequalities. A fractional order radial basis functions neural network is applied to approximateuncertainties. According to the output of the neural network, we design a general adaptive controller for fractionalorder time-delay uncertain chaotic systems with different topological structure. Furthermore, we propose an adaptivefractional order fuzzy neural network by introducing fuzzy rules into the network. Then the fractional orderextension of the Lyapunov direct method is utilized to demonstrate the stability of the error systems under theadaptive controller. Finally, numerical simulations are conducted to verify the effectiveness of the conclusions.

Biomass Chitosan-Induced Fe3O4 Functionalized Halloysite Nanotube Composites: Preparation, Characterization and Flame-Retardant Performance

Mengmeng Zhang,Yamin Cheng,Zhiwei Li,Xiaohong Li,Laigui Yu,Zhijun Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.15 No.01

An inorganic–organic nanohybrid flame retardant, HNT@CS@Fe3O4, is prepared by Halloysite nanotubes (HNT) as nanotemplate, chitosan (CS) as char-forming agent and ferroferric oxide (Fe3O4) playing in a catalytic role, aiming to endow enhanced flame-retardant performance of its nanohybrid. Results show that HNT@CS@Fe3O4 nanohybrids have a corn-like structure and can significantly improve the flame retardancy and thermal stability of epoxy resin (EP). Especially, the initial thermal degradation temperature of EP/HNT@CS@Fe3O4 is significantly improved by 24 ℃ relative to pure EP, and the residual carbon yield under air atmosphere is 8.8 wt.%, which is significantly higher than other EP composites, indicating a higher thermal stability is offered by the as-prepared nanohybrid. The limiting oxygen index of EP/10HNT@CS@Fe3O4 is 31.3%, which is 10.2% higher than that of pure EP. Meanwhile, the HNT@CS@Fe3O4 nanofiller reduces the peak heat release rate, CO production and peak smoke production release of EP nanocomposite by 32.0%, 44.0% and 33.0% in a cone calorimeter test, respectively. This is because the HNT-based composite can form a three-dimensional network structure into the EP matrix to inhibit heat release and diffusion of flammable moieties upon burning of EP. In the meantime, the incorporated Fe3O4 nanoparticle can in situ catalyze the charring of CS and EP matrix on the surface of HNT during the combustion process, which also contributes to the significantly increased fire safety of EP.

Preparation of Cobalt Ferrite Nanoparticle-Decorated Boron Nitride Nanosheet Flame Retardant and Its Flame Retardancy in Epoxy Resin

Qiaoran Zhang,Zhiwei Li,Xiaohong Li,Laigui Yu,Zhijun Zhang,Zhishen Wu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.5

Boron nitride nanosheet (BNNS) decorated with cobalt ferrite nanoparticle (CFN) to afford CFN-BNNS nanohybrid was prepared via a simple hydrothermal route and was well characterized. Subsequently, the as-prepared CFN-BNNS nanohybrid was incorporated into epoxy resin (EP) with the introduction of a weak rotary magnetic field to achieve order orientation, in order to reduce the fire risk and toxic hazards using enhanced shielding effect of BNNS upon combustion. Findings demonstrate that the CFN-BNNS nanohybrid is composed of CFN nanoparticle uniformly dispersed on BNNS surface. Thermal analysis and cone calorimeter data show that the CFN-BNNS nanofiller among EP matrix contributes to improving the char residues and mechanical properties of EP and reducing its fire risk as well as toxic hazards, especially the ordered one is advantageous over the disordered one in reducing the fire risk and toxic hazard. This is because, on the one hand, the orderly aligned BNNS as the physical barrier can more effectively prevent the transfer and diffusion of oxygen and heat. On the other hand, CFN can catalyze the degradation of EP to afford excessive chars on polymer surface; and it is also liable to decomposition during combustion, thereby generating ferrite species to promote EP degradation as well as cobalt species to enhance the oxidation of CO.

Drying performance and energy consumption of Camellia oleifera seeds under microwave-vacuum drying

Dongyan Zhang,Dan Huang,Xiyang Zhang,Hangyi Zhao,Guiliang Gong,Xiaohong Tang,Lijun Li 한국식품과학회 2023 Food Science and Biotechnology Vol.32 No.7

Microwave-vacuum drying performance and energy consumption of Camellia oleifera seeds were studied in this paper. The effects of microwave power, vacuum pressure and loading quantity were evaluated and discussed. Orthogonal experiments were also conducted to optimize the drying process. A new drying model based on the weibull distribution model was developed. Results showed that the microwave-vacuum drying process was dominated by internal water diffusion and surface water evaporation. As the microwave power and vacuum pressure increased and the loading quantity decreased, the drying time and energy consumption both decreased. However, too low or too high microwave power would increase the energy consumption. The optimal microwave-vacuum drying conditions were found to be a loading quantity of 150 g, a microwave power of 350 W and a vacuum pressure of 0.09 MPa. The developed drying model and the calculated scale and shape parameter were all consistent with experimental results.

Numerical simulation of resistance welding of solar cell using a thermal-electrical-mechanical coupled model

Xiaohong Zhan,Qi Zhang,Zhenxin Zhu,Yanhong Wei 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1

A thermal-electrical-mechanical coupled model was established to simulate the Parallel-gap resistance welding (PGRW) process between the Germanium-based solar cell and the silver interconnector. The simulated results showed that the peak temperature during PGRW is lower than the melting temperature of the base material. It is indicated that the connection mechanism of PGRW was mainly the interdiffusion and recrystallization due to pressure of electrode and the resistance heat. A detailed calculation method of current was proposed using semi-layered resistance model and layered resistance model. By comparing these models, it was found that the layered resistance model was more accurate to calculate the current value. The maximum residual stress was generated within the region under the welding electrode, while the maximum deformation was generated on the edge of the interconnector. The current variation trend predicated by the simulation results is in good agreement with the results obtained by the experiments.

The Expression Patterns of Cdc25A, Cdc25B, Sox2 and Mnb in Central Nervous System in Early Chicken Embryos

Zhang, Hui,Qin, Junhui,Cao, Jingjing,Hei, Nainan,Xu, Chunsheng,Yang, Ping,Liu, Haili,Chu, Xiaohong,Bao, Huijun,Chen, Qiusheng Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.6

The sense and antisense digoxigenin-labeled RNA probes of four genes, Cdc25A, Cdc25B, Sox2 and Mnb, were produced by using SP6 and T7 RNA polymerases, respectively, and in vitro transcription. Expression patterns of the four genes were detected by in situ hybridization in HH (Hamburger and Hamilton) stage 10 chick embryos. In general, expression patterns of the four genes were similar. mRNA of the four genes was mostly restricted to the entire CNS (central nervous system). All were confined to an identical region, neural tube, neural groove and caudal neural plate, corresponding to the notochord or spinal cord, but there was some distinction in specific region or in concentration, for example in somites. The overlap in expression at the same developmental stage in the CNS suggests that the four genes may be functional similar or related in CNS development. Expression patterns of the four genes support specific roles of these regulators in the developing CNS.

Effects of Annealing Pressures on the Ordering and Microstructures of FePt

Xiaohong Li,Zhaodi Feng,Yang Li,Wenpeng Song,Qian Zhang,Baoting Liu 한국자기학회 2013 Journal of Magnetics Vol.18 No.4

FePt:Ag (100 nm) nanocomposite thin films were prepared on naturally-oxidized Si substrates by dc magnetron sputtering at room temperature. X-ray diffraction (XRD) and transmission electron microscopy (TEM) are used to investigate the effects of annealing pressures on the ordering processes and microstructures of these films. The average sizes for the L10 ordered domains and the FePt grains are reduced to d = 9 nm and D = 13 nm from d = 19 nm and D = 34 nm, respectively, when the annealing pressure is enhanced to 0.6 GPa from room pressure at 873 K. Furthermore, the size distribution is improved into a narrow range. With increasing pressure, the coercivity of L10-FePt:Ag thin films decreases from 15.1 to 7.6 kOe. In the present study, the effects of high pressure on the L10 ordering processes and microstructures of FePt:Ag nanocomposite films were discussed.