Effects of calcination temperature on properties of sulfuric acid-assisted Y2O3 nano-powder for highly transparent ceramics

Jiao He,Xin Zhang,Jingbao Lian,Xue Zhang 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.1

The transparent Y2O3 ceramic was prepared in this work via vacuum sintering of Y2O3 nanopowder obtained by sulfuric acidassistedcalcination. The calcination temperature notably influenced the dispersion, morphology and sinterability of Y2O3nanopowders. The calcined powders at various temperatures showed similar shapes, primarily comprised of round particleswith an isotropic surface. Nevertheless, the particle size gradually increased as the calcination temperature was raised. Thepowder calcined at 1100 ℃ showed a lower agglomerate state (n = 2.19) and better sintering properties instead of thoseobtained at other calcination temperatures, which can be correlated with a larger specific surface area at the low temperatureof <1100 ℃ and the rapid growth of large particles at 1200 ℃, respectively. The powder, calcined at 1100 ℃ was vacuumsintered in transparent ceramics for 5 h at a temperature of 1700 ℃. The transparent ceramic exhibited a dense and uniformmicrostructure, and the 1.5 mm thick sample has an inline transmission of up to 70% at 800 nm wavelength

Changpingibacter yushuensis gen. nov., sp. nov., isolated from fluvial sediment in Qinghai Tibet Plateau of China

Jiao Yifan,Zhang Sihui,Yang Jing,Lai Xin-He,Dong Kui,Cheng Yanpeng,Xu Mingchao,Zhu Wentao,Lu Shan,Jin Dong,Pu Ji,Huang Ying,Liu Liyun,Wang Suping,Xu Jianguo 한국미생물학회 2022 The journal of microbiology Vol.60 No.2

Two facultatively anaerobic, short rod-shaped, non-motile, Gram-stain-positive, unknown bacterial strains (JY-X040T and JY-X174) were isolated from fluvial sediments of Tongtian River in Yushu Tibetan Autonomous Prefecture, Qinghai province, China. Cells formed translucent, gray, round and convex colonies, with a diameter of less than 0.5 mm after 5 days of incubation at 30°C on brain heart infusion-5% sheep blood agar. The 16S rRNA gene sequence similarity between strain JY-X040T and Fudania jinshanensis 313T is 93.87%. In the four phylogenetic trees constructed based on the 16S rRNA gene and 423 core genes, the two isolates form an independent branch, phylogenetically closest to F. jinshanensis 313T, but could not be classified as a member of the genus Fudania or any other genus of the family Arcanobacteriaceae. The DNA G + C content of strain JY-X040T was 57.8%. Calculation results of average nucleotide identity, digital DNADNA hybridization value and amino acid identity between strain JY-X040T and F. jinshanensis 313T are 69.9%, 22.9%, and 64.1%. The major cellular fatty acids were C16:0 (23%) and C18:1ω9c (22%). The cell-wall peptidoglycan type was A5α (L-Lys-L-Ala-L-Lys-D-Glu). The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside and four unidentified components. The whole-cell sugars contained rhamnose and ribose. MK-10(H4) was the sole respiratory quinone. The minimum inhibitory concentration of streptomycin was 32 μg/ml. All physiological, biochemical, chemotaxonomic and genomic characteristics support that strains JY-X040T and JY-X174 represent members of a novel species in a new genus, Changpingibacter yushuensis gen. nov., sp. nov. The type strain is JY-X040T (GDMCC 1.1996T = KCTC 49514T).

Optimization of Nutrients for Dinactin Production by a Marine Streptomyces sp. from the High Latitude Arctic

Jiao Zhou,Hao He,Xiaolong Wang,Jian Lu,Xiangshan Zhou,Menghao Cai,YuanXingZhang 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

Streptomyces sp. R-527F, which produces the macrotetrolide antibiotic dinactin, was isolated from the sediments of the Arctic Ocean. In this work, optimization of the nutrients required for dinactin production including medium development and precursor stimulation, were investigated. Optimization of the medium and replacement of polar sea water were achieved using a one factor at a time experiment in conjunction with statistical analysis using methods covering Plackett–Burman design, the steepest descent method and central composite design. Dinactin production in the optimized medium was 160.8 mg/L, which was 47 fold higher than the control. Supplementation of the fermentation with exogenous acetate (1.5 mmol/L), succinate (6 mmol/L), malonate (24 mmol/L) and citrate (6 mmol/L) further enhanced dinactin biosynthesis by 42.7, 122.3, 66.7, and 62.1%, respectively. The precursors, in particular succinate, facilitated sugar use and also increased pH levels. Furthermore, a six-pulse feeding of total 6 mmol/L succinate in a 5 L bioreactor fermentation yielded a maximal production of 279.0 mg/L dinactin, 124.1% higher than that without precursor stimulation. This nutritional regulation process is easy to scale up and holds the potential for adaptation to industrial use. Keywords: arctic actinomycete, fermentation, dinactin

The Prediction of Ship Motions and Added Resistance based on RANS

Jiao Yan,Dingqi Pan,Xiaomin Zhou,Ketai He 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10

In this paper, numerical predictions of ship motions and added resistance in regular head waves by solving the unsteady Reynolds average Navier-Stokes (RANS) equations with a shear-stress transport (SST) κ-ω turbulence model is presented. Volume of fluid method (VOF) is applied for the treatment of the free surface. The Wigley III ship model has been computed using the unsteady RANS solver Fluent. The simulations have been carried out to measure the heaving and pitching motions in regular head waves which covered seven different wavelengths. The Froude number of the hull are 0.2, 0.3 and 0.4. By comparing the results with the strip theory based results and experimental data, the unsteady RANS method shows better accuracy in predicting ship motions.

Research on DC Component Disturbance Suppression Strategy of Islanded T-Type Three-Level Inverter Based on Improved Backstepping Control Theory

He Guo-Feng,Zhou Zi-Chun,Luo Shuang,Li Gou-Jiao 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

Aiming at the problem that the DC component in the output voltage of the T-type three-level inverter in the island mode is obvious, due to its hardware diferences, a nonlinear control strategy combining the backstepping method, sliding mode theory, and the principle of the second-order generalized integrator (SOGI) is proposed. Firstly, the DC component in the output voltage of the inverter is regarded as a disturbance, and the mathematical model of the inverter with DC component disturbance is established. Secondly, the detected neutral point potential deviation of the DC side of the inverter is compensated to the modulation signal by proportional–integral (PI) control, to maintain the normal operating state of the three-level inverter. Then, the backstepping-sliding mode controller is constructed to improve the robustness T-type three-level inverter. And the SOGI is utilized to overcome the shortcomings of backstepping control which is easy to amplify the measurement noise and cause diferential explosion. Meanwhile, the stability of the designed controller is analyzed by using the Lyapunov stability principle. Finally, the efectiveness of the proposed control strategy is verifed by 10 kW prototype. The experimental results show that the proposed control strategy can not only efectively suppress the DC component of the inverter output voltage and improve the robustness of the system, but also has fast dynamic characteristics.

AcuD Gene Knockout Attenuates the Virulence of Talaromyces marneffei in a Zebrafish Model

( Jiao Feng ),( Zhiwen Chen ),( Liya He ),( Xing Xiao ),( Chunmei Chen ),( Jieming Chu ),( Eleftherios Mylonakis ),( Liyan Xi ) 한국균학회 2019 Mycobiology Vol.47 No.2

Talaromyces marneffei is the only dimorphic species in its genus and causes a fatal systemic mycosis named talaromycosis. Our previous study indicated that knockdown of AcuD gene (encodes isocitrate lyase of glyoxylate bypass) of T. marneffei by RNA interference approach attenuated the virulence of T. marneffei, while the virulence of the AcuD knockout strains was not studied. In this study, T. marneffei-zebrafish infection model was successfully established through hindbrain microinjection with different amounts of T. marneffei yeast cells. After co-incubated at 28_C, the increasing T. marneffei inoculum doses result in greater larval mortality; and hyphae generation might be one virulence factor involved in T. marneffeizebrafish infection. Moreover, the results demonstrated that the virulence of the DAcuD was significantly attenuated in this Zebrafish infection model.

Investigation on properties of autopolymerizing hydrogel for denture soft lining material

Jiao SUN,Miao XUE,Wei HE 대한치과재료학회 2000 대한치과기재학회 학술대회 Vol.2000 No.1

Selective adsorption of L-TA/D-TA by β-cyclodextrin derivative modified with l-tryptophan: Isotherm, kinetic and thermodynamics studies

Kaichen He,Fengxian Qiu,Jiao Qin,Jie Yan,Dongya Yang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

b-Cyclodextrin derivative modified with L-tryptophan (L-Trp-CD) was prepared for recognitive chiral separation of tartaric acid enantiomers from ethanol solution. Kinetic properties were successfully investigated by pseudo-first-order model and pseudo-second-order model. Equilibrium data were described by the Langmuir and Freundlich isotherm models. The thermodynamics parameters (positive values of DH8 and DS8, negative values of DG8) indicated that binding system for L-Trp-CD was endothermic, entropy gained and spontaneous. Selective adsorption result of L-tartaric acid (L-TA)/Dtartaric acid (D-TA) by L-Trp-CD indicated that L-Trp-CD has significantly higher adsorption capacity for L-TA compared with D-TA, and the selectivity coefficient is 3.36.

Diaporthe taoicola and D. siamensis, Two New Records on Citrus sinensis in China

( Meng Jiao Cui ),( Xin Wei ),( Peng Liang Xia ),( Ji Ping Yi ),( Zhi He Yu ),( Jian Xin Deng ),( Qi Li Li ) 한국균학회 2021 Mycobiology Vol.49 No.3

Two Diaporthe species isolated from fruit of Citrus sinensis in China were characterized based on morphology and multilocus phylogeny of ITS, tef1, and tub2 gene sequences. The phylogeny indicated that the two species match Diaporthe taoicola and D. siamensis. A critical examination of phenotypic characteristics confirmed the phylogenetic results. Diaporthe taoicola was morphologically characterized by producing Alpha conidia with tapering toward both ends. Meanwhile, D. siamensis produced cylindrical or ellipsoidal Alpha conidia with two oil drops. Pathogenicity tests revealed that both species were pathogenic to fruit of C. sinensis. To our knowledge, the two species were firstly reported on Citrus sinensis in China.

CuO-doped Ce for catalytic wet peroxide oxidation degradation of quinoline wastewater under wide pH conditions

Zhaojie Jiao,Xianming Zhang,Haifeng Gong,Donglin He,Hong Yin,Yunqi Liu,Xu Gao 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

This study aimed to treat toxic and refractory organic wastewater, and to address the limitations ofFenton method in treating organic wastewater, that the active components are easy to lose and usuallyoperate at the pH value of 2 3. In the present study, CuCe oxide catalyst was produced through citricacid-assisted complexation. Besides, the structural stability and catalytic wet peroxide oxidation (CWPO)performance of the catalyst after 5 times of application were delved into by characterization. The effectsof catalyst dosage and pH on quinoline removal were ascertained, while the reusability of the catalystwas explored. Moreover, the variations of pH, hydroxyl radical concentration and UV–Vis spectra inthe reaction system were analyzed. The possible degradation pathway and the catalytic mechanism werealso discussed. As suggested from the results, the catalyst exhibited high catalytic activity, structural stabilityand pH adaptability; it also had high CWPO performance for quinoline at the pH from 3.8 to 10.5,and the pH value need not be regulated. Under optimal conditions, 98.1% of quinoline and 86.1% of totalorganic carbon (TOC) were removed. In the CWPO process of quinoline, the OH attacked the nitrogen ringand the benzene ring in sequence.