Design and Optimization of Centralized Pneumatic Fertilizer Transporting System for Deep Fertilization Device in Paddy Field

Xiantao Zha,Guozhong Zhang,Yuhang Han,Jianwei Fu,Yong Zhou 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.3

To improve the airflow distribution consistency of each branch in the pneumatic fertilizer transportation system, so as to reduce the influence of airflow instability on the uniformity and stability of fertilizer transportation, as well as the energy waste in the process of pneumatic fertilizer transportation, a centralized pneumatic fertilizer transportation system for deep fertilization device was designed. Through theoretical calculation, the needed air flow rate, airflow speed and fertilizer pipe diameter of the system were obtained, and the fan was selected. Based on the Fluent simulation and bench tests, the influence of three air distribution method of placing fan at the end of main duct, placing fan in the middle of main duct and centralized air distribution on the airflow velocity and consistency of each branch was analyzed. The results showed that the airflow consistency of each branch in the centralized air distribution method was the best. Taking the air velocity at the outlet of each branch and its variation coefficient as the evaluation index, single factor and orthogonal simulation tests was carried out to optimize the structural parameters of centralized air distribution device. The simulation results showed that the primary and secondary factors affecting the air distribution consistency were: A (sidewall inclination angle), B (branch diameter), C (branch distance), A×B (interaction between A and B), B×C (interaction between B and C), A×C (interaction between A and C), and all the factors and their interactions had significant effects. The best parameter combination was sidewall inclination angle 15°, branch diameter 32 ㎜, branch distance 43 ㎜. With the combination, the variation coefficient of airflow velocity was 0.27% in simulation test and 1.23% in bench test. This research optimized the structure and parameters of pneumatic fertilizer transporting system, and provided references for the design and optimization of pneumatic fertilization and seeding device.

Preparation of monodisperse magnetite nanoparticles under mild conditions

Xiantao Wen,Junxiao Yang,Bin He,Zhongwei Gu 한국물리학회 2008 Current Applied Physics Vol.8 No.5

In this paper, we reported a method to prepare monodisperse magnetite nanoparticles at mild temperature using cheap and non-toxic precursors. It overcomes the shortages of chemical co-precipitation method and thermal decomposition method and combines the advantages of facile, cheap, large-scale, monodisperse, nanosize, and low synthesis temperature and low toxic. In this method, FeCl₃ㆍ6H₂O, FeCl₂ㆍ4H₂O and sodium oleate were mixed in toluene/ethanol/water mixture solvent and refluxed at 74℃ to prepare magnetite nanoparticles directly. The nanoparticles were characterized by transmission electron microscopy, dynamic light scattering, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer and thermogravimetric analysis. The magnetic properties of nanoparticles were measured by superconducting quantum interference device. The results showed that the nanoparticles are well-monodisperse with about 4–5 nm of average diameter. The nanoparticles were proved to be superparamagnetic with saturated magnetization 23.6 emu/g and blocking temperature 24.4 K. A possible formation mechanism of monodisperse magnetite nanoparticles was presented at the same time. In this paper, we reported a method to prepare monodisperse magnetite nanoparticles at mild temperature using cheap and non-toxic precursors. It overcomes the shortages of chemical co-precipitation method and thermal decomposition method and combines the advantages of facile, cheap, large-scale, monodisperse, nanosize, and low synthesis temperature and low toxic. In this method, FeCl₃ㆍ6H₂O, FeCl₂ㆍ4H₂O and sodium oleate were mixed in toluene/ethanol/water mixture solvent and refluxed at 74℃ to prepare magnetite nanoparticles directly. The nanoparticles were characterized by transmission electron microscopy, dynamic light scattering, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer and thermogravimetric analysis. The magnetic properties of nanoparticles were measured by superconducting quantum interference device. The results showed that the nanoparticles are well-monodisperse with about 4–5 nm of average diameter. The nanoparticles were proved to be superparamagnetic with saturated magnetization 23.6 emu/g and blocking temperature 24.4 K. A possible formation mechanism of monodisperse magnetite nanoparticles was presented at the same time.

Quasi-isometric and weakly quasisymmetric maps between locally compact non-complete metric spaces

Xiantao Wang,Qingshan Zhou 대한수학회 2018 대한수학회보 Vol.55 No.3

The aim of this paper is to show that there exists a weakly quasisymmetric homeomorphism $f:(X, d)\to (Y, d')$ between two locally compact non-complete metric spaces such that $f:(X, d_h)\to (Y, d'_h)$ is not quasi-isometric, where $d_h$ denotes the Gromov hyperbolic metric with respect to the metric $d$ introduced by Ibragimov in $2011$. This result shows that the answer to the related question asked by Ibragimov in 2013 is negative.

QUASI-ISOMETRIC AND WEAKLY QUASISYMMETRIC MAPS BETWEEN LOCALLY COMPACT NON-COMPLETE METRIC SPACES

Wang, Xiantao,Zhou, Qingshan Korean Mathematical Society 2018 대한수학회보 Vol.55 No.3

The aim of this paper is to show that there exists a weakly quasisymmetric homeomorphism $f:(X,d){\rightarrow}(Y,d^{\prime})$ between two locally compact non-complete metric spaces such that $f:(X,d_h){\rightarrow}(Y,d^{\prime}_h)$ is not quasi-isometric, where dh denotes the Gromov hyperbolic metric with respect to the metric d introduced by Ibragimov in 2011. This result shows that the answer to the related question asked by Ibragimov in 2013 is negative.

A second order analytical solution of focused wave group interacting with a vertical wall

Yonggang Sun,Xiantao Zhang 대한조선학회 2017 International Journal of Naval Architecture and Oc Vol.9 No.2

The interaction of focused wave groups with a vertical wall is investigated based on the second order potential theory. The NewWave theory, which represents the most probable surface elevation under a large crest, is adopted. The analytical solutions of the surface elevation, velocity potential and wave force exerted on the vertical wall are derived, up to the second order. Then, a parametric study is made on the interaction between nonlinear focused wave groups and a vertical wall by considering the effects of angles of incidence, wave steepness, focal positions, water depth, frequency bandwidth and the peak lifting factor. Results show that the wave force on the vertical wall for obliquely-incident wave groups is larger than that for normally-incident waves. The normalized peak crest of wave forces reduces with the increase of wave steepness. With the increase of the distance of focal positions from the vertical wall, the peak crest of surface elevation, although fluctuates, decreases gradually. Both the normalized peak crest and adjacent crest and trough of wave forces become larger for shallower water depth. For focused wave groups reflected by a vertical wall, the frequency bandwidth has little effects on the peak crest of wave elevation or forces, but the adjacent crest and trough become smaller for larger frequency bandwidth. There is no significant change of the peak crest and adjacent trough of surface elevation and wave forces for variation of the peak lifting factor. However, the adjacent crest increases with the increase of the peak lifting factor.

A new red-emitting phosphor of Eu3+-doped Sr2MgMoxW1−xO6 for solid state lighting

Shuo Li,Xiantao Wei,Kaimo Deng,Xiuna Tian,Yanguang Qin,Yonghu Chen,Min Yin 한국물리학회 2013 Current Applied Physics Vol.13 No.7

The white light-emitting diode has recently attracted great attention as a promising candidate for next generation lighting. The solid solution of Sr1.80Eu0.10Li0.10MgMoxW1-xO6 was synthesized via hightemperature solid-state reaction and this solid solution is treated as a promising red emitting phosphor for white light-emitting diodes. In our cases, the X-ray diffraction, excitation spectra, emission spectra and decay curves of these solid solutions were measured as a function of the Mo/W ratio to characterize the structural and luminescent properties. The excitation bands of the series of phosphors are consistent well with the region of near ultraviolet light, and the phosphors present better color purity than the commercial phosphor Y2O2S:Eu3þ in current use. Taking these properties into consideration,this kind of material may find a great potential application as a red phosphor for near-ultraviolet excited white light-emitting diodes.

Efficient Prediction Motion Vector Candidate Selection Algorithm for HEVC

Jin Ikegita,Xiantao Jiang,Tian Song,Jenq-Shiou Leu,Takashi Shimamoto 대한전자공학회 2015 ITC-CSCC :International Technical Conference on Ci Vol.2015 No.6

Fracture Properties of Wide-Notch Concrete Beams strengthened with Near-Surface Mounted CFRP Rebar

Zhenhua Ren,Xiantao Zeng,Junbo Sun,Jun Wang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.11

Carbon fiber reinforced polymer (CFRP) is a promising engineering material nowadays. This study carried out four-point-bending fracture experiment on wide-notch-concrete beams reinforced with near-surface mounted (NSM) CFRP rebar, aiming at exploring the effect of CFRP rebar on beam fracture characteristics. The test comprised four groups concrete beam specimens (three for each) with varying reinforcing methodologies. The first group specimens were common concrete beams strengthened by one near-surface mounted CFRP bar, while the second group consisted of common concrete beams strengthened by two near-surface mounted CFRP bars. On the issue of the third group, there were three wide-notch concrete beams strengthened with one near-surface mounted CFRP bar. Lastly, three wide-notch concrete beams strengthened with two near-surface mounted CFRP bars form the group four. The study proposed various equations about the rectangular concrete beams strengthened with near-surface mounted CFRP rebar under tension-shearing condition. For both open cracks and closed cracks, the equations concluded stress intensity factor as well as extending angle in mode I and II crack types. Four-point-bending fracture experiments for wide-notch-concrete beams and numerical simulation experiments were included in this research. This research exhibited expanding direction of wing type crack under effective shearing stress by the superposition model of crack tip stress intensity factor and stress intensity factor. Four-point-bending fracture tests for wide-notch-concrete beams and numerical simulation tests are finished in this research. The tests demonstrate characteristics of crack expanding direction, extending angle, vertical displacement, maximum normal stress, shear strain rate, distribution of plastic zones. Combining the theory and reality, the experimental results were in close agreement with the numerical research.

SOME EQUALITIES FOR CONTINUED FRACTIONS OF GENERALIZED ROGERS-RAMANUJAN TYPE

Yongqun Li,Xiantao Wang 대한수학회 2011 대한수학회지 Vol.48 No.5

In this paper, we rst discuss the convergence of the con-tinued fractions of generalized Rogers-Ramanujan type in the modied sense. Then we prove several equalities concerning these continued frac-tions. The proofs of our main results are mainly based on the Bauer-Muir transformation.

Inner uniform domains and the Apollonian inner metric

Yaxiang Li,Xiantao Wang 대한수학회 2013 대한수학회보 Vol.50 No.6

In this paper, we characterize inner uniform domains in Rn in terms of Apollonian inner metric and the metric j′ D when D are Apol- lonian. As an application, a new characterization for A-uniform domains is obtained.