Effect of sintering atmosphere on ferroelectric properties of SBT ferroelectric ceramics

Feng-Qing Zhang,Chunzhen Li,Haiwen Li,Xiaodong Guo,Suhua Fan 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.2

The effect of sintering atmosphere on the properties of SBT ferroelectric ceramics was studied by sol-gel method and interlayerannealing process. It was found that the sintered samples in oxygen atmosphere had more a-axis-oriented grains and moregrains which are perpendicular to the plane than those in air atmosphere. The Curie temperature of the samples obtained bysintering in oxygen and air atmosphere is Tc = 273 oC and Tc = 265 oC, and the conductivating energy Ea = 0.94 eV and Ea =0.66 eV, respectively. The residual polarization intensity of the samples sintered in air atmosphere is 2Pr = 15.3 μC/cm2, thecorresponding coercive field is Ec = 51 kV/cm; the residual polarization intensity of the sample sintered in oxygen atmosphereis 2Pr = 16.6 μC/cm2, and the corresponding coercive field is about Ec = 45 kV/cm. That is because the samples sintered in theoxygen atmosphere has larger lattice distortion, lower oxygen vacancy concentration and larger a-axis oriented grains, whichare favorable for the increase of the remnant polarization and reduction of the coercive field.

Bioelectrochemical enhancement of direct interspecies electron transfer in upflow anaerobic reactor with effluent recirculation for acidic distillery wastewater

Feng, Qing,Song, Young-Chae,Yoo, Kyuseon,Kuppanan, Nanthakumar,Subudhi, Sanjukta,Lal, Banwari Elsevier 2017 Bioresource technology Vol.241 No.-

<P><B>Abstract</B></P> <P>Methane production in the upflow anaerobic bioelectrochemical reactor (UABE) treating acidic distillery wastewater was compared to the upflow anaerobic sludge blanket reactor (UASB), and the electron transfer pathways for methane production were also evaluated in the effluent recirculation. The methane productions from reactors were influenced by the low pH of influent wastewater. However, the methane production rate and yield of the UABE were 2.08L/L.d and 320mL/g COD<SUB>r</SUB>, which were higher than the UASB. The effluent recirculation containing alkalinity neutralized the acidic influent and increased the upflow velocity in both reactors, and improved the direct interspecies electron transfer more in the UABE. When the effluent recirculation ratio was 3.0 in the UABE, the methane production rate and yield were reached up to 3.88L/L.d and 501.0mL/g COD<SUB>r</SUB>, respectively. The UABE requires electrode installation and electrical energy for operation, but the benefits from increased methane production are much higher.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electroactive bacteria enriched in UABE activate bDIET for methane production. </LI> <LI> bDIET for methane production is less susceptible to low influent pH. </LI> <LI> Effluent recirculation in UABE further improves bDIET for methane production. </LI> <LI> UABE with effluent recirculation is a recommended process for distillery wastewater. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Electroactive microorganisms in bulk solution contribute significantly to methane production in bioelectrochemical anaerobic reactor

Feng, Qing,Song, Young-Chae,Ahn, Yongtae Elsevier 2018 Bioresource technology Vol.259 No.-

<P><B>Abstract</B></P> <P>The role of anaerobic microorganisms suspended in the bulk solution on methane production was investigated in a bioelectrochemical anaerobic reactor with the electrode polarized at 0.5 V. The electron transfer from substrate to methane and hydrogen were 25% and 7.5%, respectively, in the absence of the anaerobic microorganisms in the bulk solution. As the anaerobic microorganisms increased to 4400 mg/L, the electrons transferred to methane increased to 83.3% but decreased to 0.3% in hydrogen. The electroactive microorganisms (EAM), including exoelectrogens and electrotrophs, enriched in the bulk solution that confirmed by the redox peaks in the cyclic voltammogram was proportional to the anaerobic microorganism. The methane yield based on COD removal was dependent on the anaerobic microorganisms in the bulk solution rather than on the bioelectrode surface. The EAM suspended in the bulk solution are enriched by the polarized electrode, and significantly improve methane production in bioelectrochemical anaerobic reactor.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Polarized bioelectrode enriches electroactive microorganisms (EAM) in bulk solution. </LI> <LI> EAM in bulk solution promote interspecies electron transfer for methane production. </LI> <LI> EAM contribute to greater methane production in bulk solution than on bioelectrode. </LI> <LI> Methane production strongly depends on EAM concentration in bulk solution. </LI> <LI> Bioelectrochemical methane production represents a 3-dimensional space technology. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Increased accumulation of anthocyanins in transgenic potato tubers by overexpressing the 3GT gene

Qing Wei,Qing Yang,Quan-Yi Wang,Zhi-Hang Feng,Bing Wang,Yun-Feng Zhang 한국식물생명공학회 2012 Plant biotechnology reports Vol.6 No.1

In order to explore a biotechnological method for improving potato tuber color and creating plants with increased anthocyanin contents, a potato UDP-glucose: flavonoid-3-O-glucosyltransferase (3GT) gene was inserted behind the GBSSI promoter of pBin19, and this construct was introduced into Solanum tuberosum L. cultivar De´sire´e plants by Agrobacterium-mediated transformation. Six independent transgenic lines overexpressing the 3GT gene were identified by PCR and Southern blot analysis from 18 kanamycin-resistant plants. Due to the expression of 3GT gene, the tuber color and the anthocyanin content were enhanced noticeably in the transgenic plants compared to the wild-type control plants. This result suggests that the 3GT gene can potentially be used to improve potato color and enhance levels of antioxidants in the diet.

A Study of Dynamic Forecast on Port Container Handling Capacity

Feng, Zhan-Qing,Lee, Su-Ho Korean Institute of Navigation and Port Research 2002 한국항해항만학회지 Vol.26 No.2

컨테이너 처리량(CHC)은 항만의 능력을 나타내는 중요한 지표다. 그러나 중국항만의 컨테이너 처리능력에 대한 연구는 부족하며, 연구결과 또한 예측치와 실제치와의 차이가 크다. 이는 컨테이너처리량이 다양한 경제적인 측면을 내포하고 있고 예측모델의 선택이 매우 어렵다는데 기인한다. 대체로 지금까지 사용되어왔던 회귀분석, 신경망분석 등은 과거행태모델을 벗어나지 못하고 있어 경제체제나 항만물동량의 동태적변화에 대한 고려가 결여되어 있다. 따라서 본 논문에서는 동태적 보정인과모델을 사용한 동태적 예측법을 사용해 보았고 그 결과 보다 신뢰성이 높고 현실성이 있는 연구결과를 도출할 수 있었다. In view of the great disparity between forecasts of Shanghai port container handling capacity and its real results, we choose a dynamic forecast method by the causality model dynamic compensation to predict Shanghai port container handling capacity. And we forecast Shanghai port container handling capacity by using this method. We have made a satisfactory achievement, which provides a more reliable and practical way to forecast container handling capacity.

Influence of the temperature and hydraulic retention time in bioelectrochemical anaerobic digestion of sewage sludge

Feng, Qing,Song, Young-Chae,Kim, Dong-Hyun,Kim, Mi-Sun,Kim, Dong-Hoon Elsevier 2019 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.44 No.4

<P><B>Abstract</B></P> <P>At ambient temperature (25 °C), bioelectrochemical anaerobic digestion of sewage sludge was investigated with a hydraulic retention time (HRT) of 10 days and compared to that at a mesophilic condition (35 °C). The methane production and methane content in the biogas at ambient temperature were 612.8 mL/L·d and 73.3%, respectively, which were not significantly lower than that of the mesophilic condition. Additionally, the VS removal was 54.5% which was similar for both temperature conditions. However, for a HRT of 20 days, the bioelectrochemical anaerobic digestion at ambient temperature became more stable, and the VS removal improved up to 65.0%. For the HRT of 10 days, the net energy production at ambient temperature was about 168 kJ/L·d, which was similar to the mesophilic condition; however, the apparent energy efficiency at ambient temperature was 249.2% which was significantly higher than 197.7% at the mesophilic condition. The bioelectrochemical anaerobic digestion that can save the thermal energy input at ambient temperature is recommended for the treatment of organic waste including sewage sludge in moderate and cold climate regions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The bioelectrochemical anaerobic digestion (BEAD) has advantages at ambient temperature. </LI> <LI> CH<SUB>4</SUB> production at 25 °C in BEAD is not significantly reduced compared to 35 °C. </LI> <LI> Apparent energy efficiency (249.2%) at 25 °C in BEAD is higher than at 197.2% at 35 °C. </LI> <LI> Extending HRT in BEAD improves the process stability and VS removal at 25 °C. </LI> <LI> BEAD for organic waste at 25 °C is a feasible process in moderate and cold regions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Seroprevalence of Encephalitozoon cuniculi and Toxoplasma gondii in domestic rabbits (Oryctolagus cuniculus) in China

Qing-Feng Meng,Wei-Lin Wang,Xiao-Ting Ni,Hai-Bin Li,Gui-Zhe Yao,Xiao-Lin Sun,Wei-Li Wang,Wei Cong 대한기생충학열대의학회 2015 The Korean Journal of Parasitology Vol.53 No.6

The breeding of domestic rabbits (Oryctolagus cuniculus) for human consumption has a long tradition in China. Infections that can affect the production of meat or even be transmitted from animals to humans are important to monitor, especially for public health reasons as well as for their impact on animal health. Thus, a total of 1,132 domestic rabbit sera from 4 regions in China were collected for serological screening for Encephalitozoon cuniculi and for Toxoplasma gondii by ELISA and modified agglutination test (MAT), respectively. Antibodies to E. cuniculi were detected in 248/1,132 (21.9%) sera tested while antibodies against T. gondii revealed a seroprevalence of 51/1,132 (4.5%). We believe that the present results are of epidemiological implications and public health importance due to the acknowledged susceptibility of humans to E. cuniculi and T. gondii infections. Therefore, routine screening tests of domestic rabbits are proposed considering the zoonotic potential of these parasites.

Electrical properties of predominantly (100)-oriented of Ca2+ modified SrBi4Ti4O15 thin film deposited on Pt/Ti/SiO2/Si substrates

Feng-Qing Zhang,Pengchao Dong,Suhua Fan 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.5

The predominantly (100)-oriented of Ca2+ modified SrBi4Ti4O15 (Ca0.4Sr0.6Bi4Ti4O15) thin films were fabricated by optimizing the annealing treatment using the metal organic decomposition method. We studied the capacitance-voltage (C-V) curve, the dielectric constant (ε) and the dissipation fcator (tanδ), when the thin film exhibits preferred orientation, especially. The C-V curve shows a typical butterfly loop, and the ε, tanδ are about 235 and 0.033, respectively. Meanwhile, the P-E hysteresis loop as the important characteristic was characterized. The thin film displays a well-saturated P-E hysteresis loop with remanent polarization 20.3 µC/cm2 and coercive field 132 kV/cm.

Electric field promotion of direct interspecies electron transfer for methane production in a bioelectrochemical reactor containing conductive materials

Qing Feng,Young-Chae Song 대한환경공학회 2019 대한환경공학회 학술발표논문집 Vol.2019 No.-

Carbon-based electrode fabrication and performance of bioelectrochemical anaerobic digestion for sewage sludge

Qing Feng,Zhengkai An,Rusong Zhao,Xiaoli Wang,Jun Li,송영채 한국마린엔지니어링학회 2019 한국마린엔지니어링학회지 Vol.43 No.10

Bioelectrochemical anaerobic digestion (BEAD) is a technology which exploits the potential of microorganism by supplying a small amount of electric energy in an anaerobic digester. The electrode material is one of the most important parts of a bioelectrochemical system. For the anodes and cathodes of BEAD process, graphite fiber fabric (GFF), a carbon based material with good biocompatibility and non-corrosive property, was selected and its conductivity was modified by depositing carbon nanotube (CNT) via electrophoresis deposition (EPD) method. In the BEAD process, the organic matter in the reactor is oxidized on the surface of anode forming proton, carbon dioxide and electron. The electron produced is transferred to the cathode due to the potential difference between anode and cathode, followed by methane production on the surface of cathode resulting from the combination of carbon dioxide, electron and proton. The biochemical reactions at the electrodes can be controlled by the electrode potentials. When the potential between anode and cathode was maintained at 0.3 V using an external power supply, the BEAD reactor showed remarkable performance after the start-up period of 40 days. The performance of BEAD reactor was stable in terms of pH (7.2~7.5), alkalinity (4,500~5,200mg/L as CaCO3), methane content in biogas (77.3%) and volatile fatty acid levels (VFA < 250mg HAc/L). During steady state, the specific methane production rate and VS reduction were stabilized at 412 mL CH4/L.d and 72.5%, respectively, which were much higher than the conventional anaerobic digestion. The application of bioelectrochemical technology to anaerobic digestion provides a chance to overcome the disadvantages of conventional anaerobic digestion.