MECHANOCHEMICAL SYNTHESIS OF NiO NANOPARTICLES: INSIGHT INTO THE NATURE OF PREFERRED GROWTH ORIENTATION

XIAOYU LI,HUAMING YANG,LIANGJIE FU,TIANCHENG LIU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.4

Nickel oxide (NiO) nanoparticles were synthesized by calcination at 400?C to 700?C for 8 h of theprecursor obtained via mechanochemical reaction of Ni(NO 3 ) 2 ? 6 H 2 O with citric acid as a dis-persant. The nanoparticles were characterized by thermogravimetric-diferential scanningcalorimetry (TG-DSC), X-ray difraction (XRD) and transmission electron microscopy (TEM). The kinetics of diferent surfaces of the nanocrystals under nonisothermal conditions wasinvestigated. The activation energies for diferent lattice planes of NiO nanoparticles weredetermined using the Arrhenius equation, revealing their preferred orientation. The growth ofNiO obeyed the general theory that nanoparticles with the largest surface energy tend to form. XRD data reveal that the NiO nanoparticles possess preferred (111) or (200) orientations thatre°ect their complex activity. The nature of preferred growth orientation was found to benegative difusion activity among diferent lattice surfaces, which indicates that oxygen atomsdi®use from low oxygen concentration on the lattice surface to high concentration on the latticesurface.

Role of Heat and Mass Transport on Operation and Durability of Polymer Electrolyte Fuel Cells

Ugur Pasaogullari,Richard S. Fu,Xiaoyu Zhang,M. Fazil Serincan,Josh Preston,Arnab Roy 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

Complete loss distribution model of GaN HEMTs considering the influence of parasitic parameters

Shengwei Gao,Jinrui Tian,Xiaoyu Fu,Yongxiao Li,Bo Wang,Lixia Zhao 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.1

When compared with Si-based devices, Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) possess the advantages of lower junction-to-case thermal resistance, smaller on-state resistance, faster switching velocity, and higher switching frequency. These advantages make them a promising power semiconductor device. However, with the enhancement of switching frequencies, the influence of parasitic parameters on switching ringing and the losses of GaN HEMTs are increasingly severe. Thus, it is necessary to predict the loss distribution by establishing an accurate loss model of the switching process. On the premise of considering parasitic inductance, nonlinear junction capacitance, and reverse transfer characteristics, this article proposes a precise switching loss model of GaN HEMTs to predict the loss distribution in the switching process. In addition, it verifies results based on the double pulse test (DPT) circuit, which validates the accuracy of the proposed model. Ultimately, based on the above-mentioned loss model, this article discussed the influence of parasitic capacitance and inductance on the output capacitance loss (Eqoss), the reverse conduction loss (ESD), the opening V-I overlap loss (Eopen), the closing V-I overlap loss (Eclose), and the total loss (Etotal). Then, this article produces an optimizing method to enhance the conversion efficiency of GaN HEMTs in accordance with laboratory findings.

Stable Degree Analysis for Profile of Networked Evolutionary Games With Disturbances

Ziyun Wang,Shihua Fu,Jianjun Wang,Ling Yu,Xiaoyu Zhao 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.7

This paper studies the stable degree for profile of networked evolutionary games (NEGs) with disturbances by the semi-tensor product of matrices. Firstly, the algebraic formulation of an NEG with disturbances is established. Secondly, on the basis of algebraic formulation, some concepts about stable profile with disturbances are proposed, including strong k-degree stable and weak k-degree stable, and the corresponding criteria to detect the stable degree are presented. Thirdly, two algorithms for designing controls are given to make the stable profile achieves strong k-degree stable or weak k-degree stable. Finally, an example is given to illustrate the validity of the results.

Enrichment of linoleic acid from yellow horn seed oil through low temperature crystallization followed by urea complexation method and hypoglycemic activities

Kang Yang,Ying Tang,Huayu Xue,Xiaoyue Ji,Fu-Liang Cao,Shouke Li,Li Xu 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.1

Yellow horn (Xanthoceras sorbifolia Bunge) contained abundant linoleic acid (LA), accounting for about 44% of its lipid. Here, LA was enriched by low temperature crystallization followed by urea complexation, and the optimal enrichment conditions were optimized with response surface methods (3:1 ratio of EtOH/FFA, crystallization at − 25 °C for 24.5 h; 2:1 ratio of urea/FFA1, 6.6:1 ratio of EtOH/urea, crystallization at − 10 °C for 22.4 h). Under these conditions, the final LA content and recovery were 97.10% and 62.09%, respectively. In vitro hypoglycemic studies suggested that the LA extract with stronger inhibition on α-glucosidase and lower one on α-amylase than acarbose exhibited a positive control for carbohydrate digestion with lower adverse effects. The enzyme kinetics and Lineweaver–Burk plots analyses revealed a reversible competitive inhibition on α-amylase and α-glucosidase. The findings of this research provided insights for the development of the LA extract as the functional component of health food.

Corticosterone Regulates the Expression of Neuropeptide Y and Reelin in MLO-Y4 Cells

Yuanyuan Ma,Hang Wang,Xiangnan Wu,Jing Fu,Jiefei Shen,Xiaoyu Li 한국분자세포생물학회 2012 Molecules and cells Vol.33 No.6

Osteocytes that have a dendritic appearance are widely believed to form a complex cellular network system and play crucial roles in mechanotransduction as a principal bone mechanosensor, which is the basis of their neuronal-like biology, as previously reported. Neuropeptide Y (NPY) and reelin mRNA, which are brain-specific neurogenic markers, have been identified in osteocytes. However, changes in the production of NPY and reelin in response to specific biochemical stimulation are unknown. In this study, we investigated the in vitro effect of corticosterone, one of the endogenous glucocorticoids, on the expression of NPY and reelin in the MLO-Y4 osteocyte cell line. Cells were treated with corticosterone at different concentrations (10-9 M-10-5 M) for 1, 3, 6, 12 and 24 h. As revealed, corticosterone reduced the MLO-Y4 cell viability and pro-liferation in a dose- and time-dependent manner based on an MTT assay and a Vi-CELL analyzer. The cells were then incubated with corticosterone (10-6 M), and the NPY and reelin expression levels were detected at 1, 3, 6, 12 and 24 h using real-time PCR and Western blot analysis. These results demonstrated that at the gene and the protein levels, corticosterone significantly upregulated the NPY and reelin expression in a time-dependent manner. The application of a glucocorticoid receptor antagonist, RU486, reversed the reduced cell viability and the increased expression of NPY and reelin that were caused by corticosterone. To the best of our knowledge, this is the first report to verify that corticosterone regulates the NPY and reelin expression in osteocytes.

Controlled self-assembly of low-dimensional Alq3 nanostructures from 1D nanowires to 2D plates via intermolecular interactions

Jianmin Gu,Baipeng Yin,Shaoyan Fu,Cuihong Jin,Xin Liu,Zhenpan Bian,Jianjun Li,Lu Wang,Xiaoyu Li 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.2

Due to the intense influence of the shape and size of the photon building blocks on the limitation and guidance of opticalwaves, an important strategy is the fabrication of different structures. Herein, organic semiconductor tris-(8-hydroxyquinoline)aluminium (Alq3) nanostructures with controllable morphology, ranging from one-dimensional nanowires to twodimensionalplates, have been prepared through altering intermolecular interactions with employing the anti-solvent diffusioncooperate with solvent-volatilization induced self-assembly method. The morphologies of the formed nanostructures, whichare closely related to the stacking modes of the molecules, can be exactly controlled by altering the polarity of anti-solventsthat can influence various intermolecular interactions. The synthesis strategy reported here can potentially be extended toother functional organic nanomaterials.

Tuning Molecular Composition for Better Cross-section Homogeneity of Thermal Oxidative Stabilized Polyacrylonitrile for Carbon Materials

Shiyu Liu,Yuan Ge,Baijun Liu,Zhongyu Fu,Xiaoyu Yu,Ming Yao Zhang,Hui Xuan Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

A strategy to improve the cross-section homogeneity of thermal oxidative stabilized polyacrylonitrile for carbonmaterials was provided in the present work. A kind of comonomer, dimethyl itaconate (DMI), which possesses two bulkyside groups was introduced into poly(acrylonitrile-co-itaconic acid). The efficiency of DMI in improving the cross-sectionhomogeneity of polyacrylonitrile films during thermal oxidative stabilization (TOS) processes and the properties of resultedPAN-based carbon materials were investigated in detail. It was found that DMI facilitated the formation of longer cyclicstructures, higher oxygen content, more homogeneous cross-section fracture morphology and denser structure during TOSprocess. DMI was also benefit for easing heat release. The presence of DMI also facilitated a smaller ID/IG value of thecarbonized PAN film and a bigger in-plane size of graphite crystals La.

Stochastic characteristics of reinforcement corrosion in concrete beams under sustained loads

Le Huang,Xianyu Jin,Chuanqing Fu,Hailong Ye,Xiaoyu Dong 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.25 No.5

This paper deals with the characteristics of reinforcement corrosion in concrete beams under the influence of sustained loads. The evolution and distribution laws of the reinforcement corrosion were measured periodically over time. The results show that sustained load exhibits a pronounced exacerbating effect on the reinforcement corrosion, and enlarges the nonuniformity level of corrosion as the load level increases. Accompanied with the continuous formation of the rust, the corrosion rate was also observed to be highly nonlinear and time-dependent. Moreover, to visually and quantitatively analyze the distribution of reinforcement corrosion, the 3D scanning technology combined with the probability statistics analysis was adopted, and the observed nonuniformity can be well described by the Gumbel distribution. Finally, an approach based on the three-phase spherical model was proposed to estimate the reinforcement corrosion, taking account of the effects of sustained load on the changes of concrete porosity and oxygen diffusivity.

Detrital zircon ages, sources, and implications of the Tangwangling Group, southern margin of the Ordos Block, western North China Craton

Yu Kang,Gang Chen,Qiang Chen,Fu Yang,Junping Huang,Xiaoyu Xia 한국지질과학협의회 2021 Geosciences Journal Vol.25 No.2

The southern margin of the Ordos Block (S-OB) is located in the western part of the southern region of the North China Craton (S-NCC), and has been involved in multiple orogenic episodes that uplifted the North Qinling Orogenic Belt (NQB). Determining whether the S-OB deposits and sources were controlled by late Precambrian or Ordovician tectonic sedimentation is extremely important for understanding the paleo-tectonic evolution of the S-NCC and its relationship with the North Qinling Terrane (NQT). In this study, the depositional age and trace of the source area of the Tangwangling Group (TWL) were constrained using detrital zircon U-Pb isotopic analyses. Six sandstone samples collected from the TWL Group yielded similar detrital zircon age patterns, with four distinct clusters at 2588–2305 Ma, 2100–1600 Ma, 1251–1005 Ma 995–744Ma which correspond to peak ages of 2.45 Ga, 1.80 Ga, 1.10 Ga, and 0.82 Ga, respectively. The youngest zircon ages that peak at 0.82 Ga suggest that the depositional age of the TWL Group is the closest to the late Neoproterozoic, based on comparisons with geochronological data from late Precambrian and Ordovician successions that outcrop in the OB. The detrital zircon age ranges of the TWL Group, in comparison with those of the NCC and NQT, also indicate that clastic grains deposited in the TWL Group were mainly sourced from NCC basement rocks and less so from the late Precambrian NQT complex, which was coincident with a Grenvillian-aged tectonomagmatic event. Thus, we conclude that the NQT had accreted onto the S-NCC before the TWL Group were deposited during the late Neoproterozoic, implying that the S-NCC or the S-OB may have experienced or was at least influenced by the assembly and breakup of Rodinia.