Growth behavior of low-dimensional nano ZnO on a biomorphic porous carbon (BPC) matrix by a hydrothermal synthesis method

Dongyun Li 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.1

In this paper, the growth behavior of low-dimensional nano ZnO on biomorphic porous carbon matrix (BPC matrix) by a hydrothermal synthesis method is studied. The Influence of the growth time, type of BPC matrix and its carbonization temperature on the growth behavior of nano ZnO are studied through XPS, XRD, TGA, SEM etc. The results show that hexagonal ZnO is obtained on a BPC matrix and the grain size is about 8 nm. Zero-dimensional nano-ZnO particles can grow on the inner walls of BPC matrix derived from hardwood, it is distributed evenly and combines well with the walls; while onedimensional nano rods or two-dimensional nano sheets can grow on that of bamboo and two-dimensional nano sheets can grow on that of pine. The morphology, size and amount of nano-ZnO crystals are mainly controlled by growth time and matrix carbonization temperature, respectively. The growth mechanism of nano-ZnO crystal on a BPC matrix is also discussed.

The Research and Application of Reservoir Identification Model Based on Smap-ED

Huoyou Li,Jia Zhao,Dongyun Lin,Jingsong Su,Qingqiang Wu,Qingqi Hong 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.12

In order to provide a scientific decisions for prospect new oil formation and reduce production costs, this paper proposed reservoir identification model based on Smap-ED. Using the actual seismic attribute data as the research object, the principles are analyzed to explore the reservoir recognition model , Through the experimental analysis of model of effectiveness evaluation indexes , the five models of applicability and effectiveness was comparative study from the relative index, external index and running time. The experimental results show model based on Smap-ED of seismic attribute data clustering effect is better than model based on S-Map and the running time of algorithm close to model based on SOM, this model can provide more effective support for scientific decision-making.

Hydrothermal Synthesis of PbTiO3 Nanocrystals with a pH-Adjusting Agent of Ammonia Solution

Xinyi Li,Zhi-Xiong Huang,Lian-Meng Zhang,Dongyun Guo 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.5

The PbTiO3nanocrystals were synthesized by a hydrothermal method, and ammonia solution was firstly used as a pH-adjustingagent. The effect of ammonia concentration on formation and morphologies of PbTiO3nanocrystals was investigated. At low ammonia concentration (0–2.2 mol/L), no perovskite PbTiO3phase was formed. When the ammonia concentrationwas 4.4 mol/L, the rod-like PbTiO3nanocrystals with highly crystalline were successfully synthesized. As the ammoniaconcentration further increased to 13.2 mol/L, the flake-like PbTiO3nanocrystals were formed.

Structural evolution of the thermal conversion products of modified coal tar pitch

Qi Li,Dongyun Han,Haiyan Qiao,Weiwei Shi,Yuqi Zhang,Zubin Cao 한국탄소학회 2023 Carbon Letters Vol.33 No.1

Coal tar pitch is a product with high carbon content and aromatic compounds. Modified coal tar pitch is a high quality raw material for the preparation of intermediate phase pitch, needle coke, carbon microspheres, et al. In this paper, modified coal tar pitch was used as raw material, nitrogen was used as protective gas, and thermal conversion was carried out at constant temperatures (370, 390, 410, 420 °C). Polarized light microscopy, SEM, elemental analysis, FTIR spectroscopy, Raman spectroscopy and XRD diffraction combined with split-peak fitting were used to characterize the microstructures of the thermal transformation products. The results showed that the Iar and CH3/ CH2 contents of the products increased with the gradual increase of the thermal conversion temperature, and the aromatic content increased. And the higher the temperature at the same heating rate, the more the ideal graphite microcrystal content, and the defective graphite microcrystals are converted into ideal graphite microcrystals during the thermal conversion process. When the reaction temperature exceeds 390 °C, the microstructure of the thermal transformation products is anisotropic spheres, and the small spheres fuse with each other and tend to be basin-like and mosaic structure as the temperature increases.

Crystallization kinetics and magnetic properties of spinel transition metal ferrite nanoparticles

Yukun Sun,Dongyun Li,Pengzhao Gao,Zhouli Lu,Hongliang Ge 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.5

Spinel transition metal ferrite TMFe2O4 (TM = Co2+, Ni2+, Cu2+, and Zn2+) nanoparticles were prepared via a template-assistedsol-gel method followed by a calcining process, using metal nitrate precursors as raw materials. The prepared specimens werecharacterized using X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). Their structures, magneticproperties, crystallization kinetics, and the influence of crystal size (D) on the magnetic properties were investigated. It wasfound that the crystal sizes of TMFe2O4 were positively proportional to the calcined temperature and time, and thecrystallization growth activation energy (Ea) increased with the increase of metal ionic radius. The optimum calcinationparameters were obtained to form a crystal closest to the standard crystal. Additionally, the saturation magnetization ofinverse spinel structure specimens was enhanced monotonously and their coercivity showed a potential decrease trend, whilethere was an opposite change trend for normal spinel structure specimens.

Magnetic Microstructures and Corrosion Behaviors of Nd-Fe-B-Ti-C Alloy by Ga Doping

Qiong Wu,Pengyue Zhang,Hongliang Ge,Aru Yan,Dongyun Li 한국자기학회 2013 Journal of Magnetics Vol.18 No.3

The influences of Gallium doping on the magnetic microstructures and corrosion behaviors of Nd-Fe-B-Ti-C alloys are investigated. The cooling rate for obtaining fully amorphous structure is raised, and the glassforming ability is improved by the Ga addition. The High Resolution Transmission Electron Microscopy image shows that the α-Fe and Fe3B soft magnetic phases become granular surrounded by the Nd2Fe14B hard magnetic phase. The rms and (Δ?)rms value of Nd-Fe-B-Ti-C nanocomposite alloy thick ribbons in the typical topographic and magnetic force images detected by Magnetic Force Microscopy(MFM) decreases with 0.5 at% Ga addition. The corrosion resistances of Nd9Fe73B₁₂.6C ₁.₄Ti₄-xGax (x = 0, 0.5, 1) alloys are enhanced by the Ga addition. It can be attributed to the formation of more amorphous phases in the Ga doped samples.

Experimental and Numerical Analysis of the Construction Process for the Oblique Cantilevered Steel Reinforced Concrete Structure

Qinglin Tao,Wanyun Yin,Rencai Jin,Feng Yu,Beng Niu,Yi Hu,Zhitao Li,Quanwei Liu,Yuandi Qian,Dongyun Jia 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.5

The oblique cantilevered steel reinforced concrete structure (OCSRCS) which includes members of oblique beam, upright column, and the oblique column is manly applied in Olympic Sports Center Stadium and has the characteristics of large section, long span, and large inclination angle. For the safe and economical construction of the OCSRCS, a new construction method named Self-balancing and Self-supporting Method is proposed to take place of traditional construction method of Full-space Support. In this method, cables are utilized to transfer the lateral pressure and gravity load of concrete in pouring to the embedded steel in the OCSRCS and the platform. For ensure the safety of this method, the fi nite element method is proposed to predict the mechanical behavior of the OCSRCS in construction, and the strain variation of the embedded steel in the OCSRCS during the construction process has also observed by the in-situ experiment. The stress distribution of steel and cables in the OCSRCS is investigated and validated in this paper. The results show that the Self-balancing and Self-supporting Method for the OCSRCS can eff ectively ensures the safety of the construction, and it provides references for the construction of large-scale OCSRCS in engineering.