Excellent microwave absorption of FeCo/ZnO composites with defects in ZnO for regulating the impedance matching

Bao, Xiukun,Wang, Xiaolei,Zhou, Xinao,Shi, Guimei,Xu, Ge,Yu, Jin,Guan, Yinyan,Zhang, Yajing,Li, Da,Choi, Chuijin Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.769 No.-

<P><B>Abstract</B></P> <P>FeCo/ZnO composites have been successfully prepared through liquid-phase reduction process for the formation of FeCo polyhedrons and sequentially thermal decomposition of colloidal mixture of FeCo and Zn(Ac)<SUB>2</SUB>·2H<SUB>2</SUB>O under nitrogen atmospheres. ZnO nanoparticles are homogeneously deposited on the surface of FeCo polyhedrons and the level of oxygen-vacancy defects in ZnO can be elevated with the increase of ZnO content. By comparison with FeCo polyhedrons, FeCo/ZnO composites exhibit excellent microwave absorption. The optimal RL value can reach −34.8 dB at 14.8 GHz and effective bandwidth (RL < −10 dB) is 5.1 GHz in the frequency range of 12.4–17.5 GHz with a matching thickness of 1.5 mm. The integrated bandwidth with RL < −10 dB can reach 14.1 GHz covering 3.4–17.5 GHz. Theory analysis demonstrates the interfacial polarization, dipole polarization and high conductivity due to oxygen-vacancy defects in FeCo/ZnO composites contribute to enhancement of dielectric loss capacity, which is more favorable for impedance matching.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The preferable impedance matching of FeCo/ZnO composites can be achieved by regulating the ZnO content. </LI> <LI> The optimal reflection loss (RL) can reach −34.8 dB with a matching thickness of 1.5 mm. </LI> <LI> The effective bandwidth with RL < −10 dB achieve 14.1 GHz covering 3.4–17.5 GHz with integrated thickness of 1.5–5 mm. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Corroded pipeline failure analysis using artificial neural network scheme

Xu, Wen-Zheng,Li, Chun Bao,Choung, Joonmo,Lee, Jae-Myung Elsevier Applied Science 2017 Advances in engineering software Vol.112 No.-

<P><B>Abstract</B></P> <P>Corrosion defects occur very often on the internal and external surfaces of pipelines, which may result in a serious threat to the integrity of the pipelines. Numerous studies investigated failure behavior of corroded pipelines with single corrosion defects. However, few studies focus on interacting corrosion defects. Interacting defects are defined as defects with certain proximity that interact to reduce the overall strength of a pipeline. In the present study, the failure behavior of pipelines with interacting corrosion defects was studied using a finite element method, and then a solution was proposed to predict burst pressure using an artificial neural network. The solution was validated by experimental results in previous studies and compared with other existing assessment solutions to prove its applicability and efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The failure behavior of pipelines with interacting corrosion defects was studied using FE method. </LI> <LI> A series of models were created for the sensitive study of the various parameters. </LI> <LI> A solution was proposed to predict burst pressure using an artificial neural network (ANN). </LI> <LI> The solution was validated by comparing with experimental results and existing codes. </LI> </UL> </P>

Tunable magnetic properties of double perovskite La₂Fe_2-xCo_xO₆

Wang, Weihua,Feng, Wuwei,Yuan, Jiangyan,Pang, Ning,Zhao, Xiaoxue,Li, Meiyun,Bao, Zhidi,Zhu, Kun,Odkhuu, Dorj Elsevier 2018 PHYSICA B-CONDENSED MATTER - Vol.540 No.-

<P><B>Abstract</B></P> <P>Double perovskite La<SUB>2</SUB>Fe<SUB>2-x</SUB>Co<SUB>x</SUB>O<SUB>6</SUB> was prepared and studied. Orthorhombic and trigonal structures were obtained depend on the molar ratio of Fe to Co. Fe-rich sample demonstrate ferrimagnetic properties; with increasing content of Co, trigonal structure is favored and the net magnetic moment of sample decrease gradually to zero. Our experimental results were further supported by first-principle theoretical calculations and demonstrate that La<SUB>2</SUB>Fe<SUB>2-x</SUB>Co<SUB>x</SUB>O<SUB>6</SUB> is a new high <I>T</I> <SUB> <I>c</I> </SUB> ferromagnetic semiconductor with tunable magnetic properties and is thus a promising material for spintronics devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phase-pure double perovskite La2Fe2-xCoxO6 was prepared. </LI> <LI> Orthorhombic and trigonal structures were obtained depending on the ratio of Fe to Co. </LI> <LI> La2Fe2-xCoxO6 is a new high Tc ferromagnetic semiconductor with tunable magnetic properties. </LI> <LI> Theoretical ab initio calculations further support our experimental results. </LI> </UL> </P>

Antioxidant Flavone Glycosides from the Root of Pteroxygonum giraldii

Li, Bao-Lin,Yang, Zhan-Jun,Jiang, Lin-Ling,Zhang, Xi-Quan,Gu, Hong-Mei,Wang, Hui-Chun,Tian, Xian-Hua Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.7

Two new flavone glycosides, giraldiin A and B, together with three known compounds, annulatin, myricetin 3-O-$\alpha$- L-rhamnopyranoside and gallic acid, were isolated from the ethanol extract of the root of Pteroxygonum giraldii Damm. et Diels. The structures of giraldiin A and B are designated as 3'-($\alpha$-L-arabinopyranosyloxy)-4',5,5',7- tetrahydroxy-3-methoxyflavone and 4'-($\beta$-D-glucopyranosyloxy)-5,5',7-trihydroxy-2',3-dimethoxyflavone, respectively, on the basis of detailed spectroscopic analyses. The free radical scavenging activity of giraldiin A was evaluated by decolouring spectrophotometry of pentamethine cyanine dye (Cy5) with $Fe^{2+}-H_2O_2$ Fenton radical generating system. The results indicated the hydroxyl free radical scavenging activity of giraldiin A (E$D_{50}$ = 23.7 nmol/mL) is higher than that of some known antioxidants such as rutin, puerarin, daidzein and 2,6-di-tertbutyl-4-methylphenol.

Influences of two-step calcinations upon the fabrication and morphological control of Lu2Ti2O7 powders using oxides as precursors

Bao-rang Li 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.1

Based on observations of the influence of calcination temperature and annealing time on the synthesis of Lu2Ti2O7 powders under molten salt conditions, a new route for preparing nano-ceramic powders from oxides, two-step calcinations (TSC), is suggested in this paper. Moreover, the TSC process was investigated in detail using XRD and SEM technologies. Commercial ceramic oxide powders TiO2 (particle size 20 nm) as well as Lu2O3 (particle size 3-4 um) were used as the raw materials and further calcinated with different heating schedules. The results showed that TSC could retard the grain growth and accelerate the phase transformation of Lu2Ti2O7 more effectively in comparison with single-step calcination (SSC). By controlling the calcination temperature and time, spherical Lu2Ti2O7 powders with nano-sized particles were achieved from oxide precursors by TSC.

Effects of Wind Generation Uncertainty and Volatility on Power System Small Signal Stability

Li-Bao Shi,Li Kang,Liang-Zhong Yao,Shi-Yao Qin,Rui-Ming Wang,Jin-Ping Zhang 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.1

This paper discusses the impacts of large scale grid-connected wind farm equipped with permanent magnet synchronous generator (PMSG) on power system small signal stability (SSS) incorporating wind generation uncertainty and volatility. Firstly, a practical simplified PMSG model with rotor-flux-oriented control strategy applied is derived. In modeling PMSG generator side converter, the generator-voltage-oriented control strategy is utilized to implement the decoupled control of active and reactive power output. In modeling PMSG grid side converter, the grid-voltageoriented control strategy is applied to realize the control of DC link voltage and the reactive power regulation. Based on the Weibull distribution of wind speed, the Monte Carlo simulation technique based is carried out on the IEEE 16-generator-68-bus test system as benchmark to study the impacts of wind generation uncertainty and volatility on small signal stability. Finally, some preliminary conclusions and comments are given.

Vortex-induced Vibration Control by Micro Actuator

Bao-Qing Li,Yang Liu,Jia-Ru Chu 대한기계학회 2007 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.21 No.9

The control of vortex-induced vibration of two side-by-side circular cylinders in a cross flow is carried out experimentally. One cylinder is elastically supported and the other is fix-supported at both ends. The two cylinders vibrate under the action of the unsteady flow-induced forces. A micro actuator is embedded on the surface of each cylinder to perturb the boundary layer. The spacing ratio is set at 1.2. The measurement shows that the structural vibration can be suppressed significantly when the reduced excitation frequency is around 2.655.

Association Between the GSTP1 Codon 105 Polymorphism and Gastric Cancer Risk: an Updated Meta-analysis

Bao, Li-Dao,Niu, Jian-Xiang,Song, Hui,Wang, Yi,Ma, Rui-Lian,Ren, Xian-Hua,Wu, Xin-Lin Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Objective: The current meta-analysis was performed to address a more accurate estimation of the association between glutathione S-transferase P1 (GSTP1) codon 105 polymorphism and risk of gastric cancer (GC), which has been widely reported with conflicting results. Methods: A comprehensive literature search was conducted to identify all the relevant studies. Fixed or random effect models were selected based on the heterogeneity test. Publication bias was estimated using Begg's funnel plots and Egger's regression test. Results: A total of 20 studies containing 2,821 GC cases and 6,240 controls were finally included in the analyses. Overall, no significant association between GSTP1 polymorphism and GC risk was observed in worldwide populations. However, subgroup analysis stratified by ethnicity showed that GSTP1 polymorphism was significantly associated with increased risk of GC in Asians (G vs. A, OR = 1.273, 95%CI=1.011-1.605; GG vs. AA, OR=2.103, 95%CI=1.197-3.387; GG vs. AA+AG, OR =2.103, 95%CI=1.186-3.414). In contrast, no significant association was found in Caucasians in any genetic models, except for with AG vs. AA (OR=0.791, 95%CI=0.669-0.936). Furthermore, the GSTP1 polymorphism was found to be significantly associated with GC in patients with H. pylori infection and in those with a cardiac GC. Subgroup analysis stratified by Lauren's classification and smoking status showed no significant association with any genetic model. No studies were found to significantly influence the pooled effects in each genetic mode, and no potential publication bias was detected. Conclusion: This meta-analysis suggested that the GSTP1 polymorphism might be associated with increased risk of GC in Asians, while GSTP1 heterozygote genotype seemed to be associated with reduced risk of GC. Since potential confounders could not be ruled out completely, further studies are needed to confirm these results.

Roles of microRNA-206 in Osteosarcoma Pathogenesis and Progression

Bao, Yun-Ping,Yi, Yang,Peng, Li-Lin,Fang, Jing,Liu, Ke-Bin,Li, Wu-Zhou,Luo, Hua-Song Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6

Backgroud and Aims: MicroRNA-206 has proven to be down-regulated in many human malignancies in correlation with tumour progression. Our study aimed to characterize miR-206 contributions to initiation and malignant progression of human osteosarcoma. Methods: MiR-206 expression was detected in human osteosarcoma cell 1ine MG63, human normal osteoblastic cell line hFOB 1.19, and paired osteosarcoma and normal adjacent tissues from 65 patients using quantitative RT-PCR. Relationships of miR-206 levels to clinicopathological characteristics were also investigated. Moreover, miR-206 mimics and negative control siRNA were transfected into MG63 cells to observe effects on cell viability, apoptosis, invasion and migration. Results: We found that miR-206 was down-regulated in the osteosarcoma cell line MG63 and primary tumor samples, and decreased miR-206 expression was significantly associated with advanced clinical stage, T classification, metastasis and poor histological differentiation. Additionally, transfection of miR-206 mimics could reduce MG-63 cell viability, promote cell apoptosis, and inhibit cell invasion and migration. Conclusions: These findings indicate that miR-206 may have a key role in osteosarcoma pathogenesis and development. It could serve as a useful biomarker for prediction of osteosarcoma progression, and provide a potential target for gene therapy.

Effects of Furnished Cage Type on Behavior and Welfare of Laying Hens

Li, Xiang,Chen, Donghua,Li, Jianhong,Bao, Jun Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.6

This study was conducted to compare the effects of layout of furniture (a perch, nest, and sandbox) in cages on behavior and welfare of hens. Two hundred and sixteen Hyline Brown laying hens were divided into five groups (treatments) with four replicates per group: small furnished cages (SFC), medium furnished cages type I (MFC-I), medium furnished cages type II (MFC-II), and medium furnished cages type III (MFC-III) and conventional cages (CC). The experiment started at 18 week of age and finished at 52 week of age. Hens' behaviors were filmed during the following periods: 8:00 to 10:00; 13:00 to 14:00; 16:00 to 17:00 on three separate days and two hens from each cage were measured for welfare parameters at 50 wk of age. The results showed that feeding and laying of all hens showed no effect by cage type (p>0.05), and the hens in the furnished cages had significantly lower standing and higher walking than CC hens (p<0.05). The birds in MFC-III had significant higher preening, scratching and feather-pecking behavior than in the other cages (p<0.05). No difference in nesting behavior was found in the hens between the furnished cages (p>0.05). The hens in MFC-I, -II, and -III showed a significant higher socializing behavior than SFC and CC (p<0.05). The lowest perching was for the hens in SFC and the highest perching found for the hens in MFC-III. Overall, the hens in CC showed poorer welfare conditions than the furnished cages, in which the feather condition score, gait score and tonic immobility duration of the hens in CC was significantly higher than SFC, MFC-I, MFC-II, and MFC-III (p<0.05). In conclusion, the furnished cage design affected both behavior and welfare states of hens. Overall, MFC-III cage design was better than SFC, MFC-I, and MFC-II cage designs.