Research on grain composition, grain size and electrical conductivity of the CuCr1-xMgxO2 (0 ≤ x ≤ 0.08)

Yanyan Tang,Yiding Hu,Yi Li,Haorong Wu,Liangwei Chen,Lan Yu 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.5

A series of layered CuCr1-xMgxO2 (0 ≤ x ≤ 0.08) polycrystalline ceramics were prepared. The effects of substituting Mg2+cations for Cr3+ cations on the grain composition, grain size, grain quantity, and electrical conductivity were investigated. When x = 0–0.04, the distinct layered structure grain grew rapidly with the increase of magnesium in the composition, andthe average grain size increased from 2.5 μm (x = 0) to 15 μm (x = 0.04) due to the decrease of activation energy. Furthermore,the bulk density and lattice constant also reached the maximum and minimum values of 4.367 g/cm3 and 17.083 respectivelyat x = 0.04. When x = 0.05–0.08, the average grain size slightly decreased due to the grown-up second-phase MgCr2O4hindering of grain growth. The results showed that the average size of the second-phase MgCr2O4 had reached 1.3 μm whenx = 0.04. In general, the larger the grain size of polycrystalline ceramics, the more defects in the grain boundaries, and thebetter its electrical conductivity. Therefore, the solid-phase reaction, which can obtain larger grain size and more grainboundary defects, was chosen here to prepare CuCr1-xMgxO2 polycrystalline ceramics, so as to obtain a highly conductiveCuCr1-xMgxO2 ceramic material. The minimum resistivity of the obtained CuCr0.6Mg0.4O2 polycrystalline ceramic is only 0.091Ω·cm, which is of great significance for the development of transparent conductive oxides.

Transcriptome analysis of colchicine-induced tetraploid Kiwifruit leaves with increased biomass and cell size

Zhu Yanyan,Tang Wei,Tang Xiaofeng,Wang Lihuan,Li Wei,Zhang Qian,Li Mingzhang,Fang Congbing,Liu Yongsheng,Wang Songhu 한국식물생명공학회 2021 Plant biotechnology reports Vol.15 No.5

Colchicine-induced polyploidization has been extensively utilized in plant-breeding programs to increase biomass and overall yield of various crop species. Chromosome doubling usually increases the plant size and cell size. However, the underly- ing mechanisms remain elusive. In this study, we showed that 0.1% colchicine is an optimized concentration for inducing tetraploidization of Actinidia chinensis var. chinensis ‘Hongyang’, a commercially important diploid kiwifruit cultivar. The tetraploid plants showed increased plant height, leaf size, and biomass, as compared with the corresponding diploid plants. Scanning electron microscopy and histological analysis indicated that the leaf cell size was significantly increased in the tetraploid plants. Our further transcriptome analysis revealed the 5922 differentially expressed genes between the diploid and tetraploid plants. Gene Ontology analysis enriched the cell wall-related genes, including the pectin methylesterases (PMEs) and expansins (EXPs), both of which play a critical role in cell wall loosening and extension. The increased expression of PME and EXP genes might contribute to the increased cell size in the tetraploid plants. Together, our work indicated that tetraploidization increases the organ and cell size in kiwifruit, possibly by enhancing the cell wall extensibility.

Characterization of a Family 3 Polysaccharide Lyase with Broad Temperature Adaptability, Thermo-alkali Stability, and Ethanol Tolerance

JunPei Zhou,Yanyan Dong,Yajie Gao,Xianghua Tang,Junjun Li,YUN-JUAN YANG,Bo Xu,Zhenrong Xie,Zunxi Huang 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.4

The 774-bp pectate lyase gene plyAI4 from Bacillus sp. I4 was cloned and expressed in E. coli. The gene encodes a 257-residue polypeptide (PlyAI4, 28.3 kDa)with the highest identities of 97.3% with a putative pectate lyase from Bacillus subtilis BSn5 (ADV94306) and 60.3%with an identified pectate lyase of the polysaccharide lyase family (PL) 3 from Paenibacillus amylolyticus 27C64(ADB78774). The purified recombinant PlyAI4 (rPlyAI4)exhibited apparently optimal activity at pH 10.5 ~ 11.0 and 50oC. Compared with the majority of reported alkaline pectate lyases, rPlyAI4 exhibited more residual enzyme activity at 20oC (~45%) or at 70oC (~50%) and better thermostability at 70oC (~60 min half-life at 70oC). In the presence of 20% (v/v) ethanol, pectate lyase activity was enhanced by 0.2 fold. After incubation in 40% (v/v)ethanol at 37oC and pH 8.5 for 1 h, the purified rPelAI4retained more than 75% of the initial activity. Sequence analysis proposed a new signature block, A-D-G-[V/I]-H,for PL 3 pectate lyases. These properties may prove to be important with regards to PlyAI4 for basic research and industrial application.

BERGMAN TYPE OPERATORS ON SOME GENERALIZED CARTAN-HARTOGS DOMAINS

He, Le,Tang, Yanyan,Tu, Zhenhan Korean Mathematical Society 2021 대한수학회지 Vol.58 No.6

For µ = (µ₁, …, µ_t) (µ_j > 0), ξ = (z₁, …, z_t, w) ∈ ℂ^n₁ × … × ℂ^n_t × ℂ^m, define $${\Omega}({\mu},t)=\{{\xi}{\in}\mathbb{B}_{n_1}{\times}{\cdots}{\times}\mathbb{B}_{n_t}{\times}\mathbb{C}^m:{\parallel}w{\parallel}^2<C({\chi},{\mu})\prod_{j=1}^{t}(1-{\parallel}z_j{\parallel}^2)^{{\mu}_j}\},$$ where $\mathbb{B}_{n_j}$ is the unit ball in ℂ^n_j (1 ≤ j ≤ t), C(χ, µ) is a constant only depending on χ = (n₁, …, n_t) and µ = (µ₁, …, µ_t), which is a special type of generalized Cartan-Hartogs domain. We will give some sufficient and necessary conditions for the boundedness of some type of operators on L^p(Ω(µ, t), ω) (the weighted L^p space of Ω(µ, t) with weight ω, 1 < p < ∞). This result generalizes the works from certain classes of generalized complex ellipsoids to the generalized Cartan-Hartogs domain Ω(µ, t).

ON COMMUTING GRAPHS OF GROUP RING Z_nQ₈

Chen, Jianlong,Gao, Yanyan,Tang, Gaohua Korean Mathematical Society 2012 대한수학회논문집 Vol.27 No.1

The commuting graph of an arbitrary ring R, denoted by ${\Gamma}(R)$, is a graph whose vertices are all non-central elements of R, and two distinct vertices a and b are adjacent if and only if ab = ba. In this paper, we investigate the connectivity, the diameter, the maximum degree and the minimum degree of the commuting graph of group ring $Z_nQ_8$. The main result is that $\Gamma(Z_nQ_8)$ is connected if and only if n is not a prime. If $\Gamma(Z_nQ_8)$ is connected, then diam($Z_nQ_8$)= 3, while $\Gamma(Z_nQ_8)$ is disconnected then every connected component of $\Gamma(Z_nQ_8)$ must be a complete graph with a same size. Further, we obtain the degree of every vertex in $\Gamma(Z_nQ_8)$, the maximum degree and the minimum degree of $\Gamma(Z_nQ_8)$.

Electrochemical Performance of Lithium-Ion Capacitors Using Pre-Lithiated Multiwalled Carbon Nanotubes as Anode

Manyuan Cai,Xiaogang Sun,Yanyan Nie,Wei Chen,Zhiwen Qiu,Long Chen,Zhenhong Liu,Hao Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.4

Pre-lithiated multiwalled carbon nanotube anode was prepared by internal short circuit approach (ISC) for 5 min, 30 min, 60 min and 120 min respectively. Lithium ion capacitors (LICs) were assembled by using pre-lithiated multiwalled carbon nanotubes as anodes and activated carbon (AC) as cathodes. The structure of multiwalled carbon nanotubes and electrodes were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performance of pre-lithiated multiwalled carbon nanotube electrodes and pristine carbon nanotube electrodes were tested by galvanostatic charge/discharge and electrochemical impedance. The results indicated that pre-lithiation carbon nanotubes greatly improved the charge/discharge performance of LICs. The energy density was four times than conventional electric double-layer capacitors (EDLCs) at the current density of 100 mA/g. The LICs achieved a specific capacitance of 59.3 F/g at the current density of 100 mA/g with 60 min pre-lithiatiation process. The maximum energy density and power density was 96Wh/kg and 4035W/kg, respectively. The energy density still remained about 89.0% after 1000 cycles. The LIC showed excellent supercapacitor performance.

Detection of duck hepatitis virus serotype1 by biosensor based on imaging ellipsometry

Chenghong Huang,Jixiang Li,Yu Tang,Yanyan Chen,Gang Jin 한국물리학회 2011 Current Applied Physics Vol.11 No.3

A novel method for the detection of duck hepatitis virus serotype1 (DHV1) using a biosensor based on imaging ellipsometry (IE) is developed. Polyclonal antibodies against DHV1 were immobilized on silicon wafers through protein A and used to capture virus particles in sample. Signals on silicon surface were acquired directly in grayscale format on an imaging ellipsometry image. This study demonstrated that the assay is rapid and accurate for detection of duck hepatitis virus. Compared with traditional methods,this technique not only has high sensitivity as low as 8 × 10^-9.5 LD_50/ml, but can also simultaneously perform multiple serotype identification of DHV1, DHV1-g and DHV1-s. These results suggest that this biosensor might be a practicable diagnostic tool for duck hepatitis virus detection.

A Gel-like Comb Micro-Block Hydrophobic Associating Polymer: Synthesis, Solution Property and the Sol-Gel Transition at Semi-Dilute Region

Wanfen Pu,Feng Jiang,Bing Wei,Yanli Tang,Yanyan He 한국고분자학회 2017 Macromolecular Research Vol.25 No.2

The gel-like comb micro block hydrophobic associating polymer (CBHAP) was synthesized by mixed micellar polymerization. The chemical structure of the copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR). The rheological properties of CBHAP in fresh water and saline water at semi-dilute region were investigated. The experimental results show that, because of the intermolecular forces, shear thickening phenomenon can be observed obviously in brine solution and the Newtonian viscosity plateau could be observed clearly before 40 s-1. When the concentration reaches 3,000 mg/L, the G’ and G’’ becomes stable, indicating that CBHAP experiences the sol-gel transition after 3,000 mg/L. However, the curl structure is formed by adding salt, resulting in a higher concentration of the sol-gel transition than that in fresh water. Once the curl structure is destroyed by shearing or stretching, the intermolecular forces will take into effect and complete the sol-gel transition at semi-dilute region.

Enhanced corrosion resistance by polypyrrole and Ti3C2Tx-acrylic epoxy double-layer coating for 304SS bipolar plates of PEMFC

Haifeng Bian,Guoli Zhang,Qingxi Zhai,Yanyan Du,Yujie Ma,Beibei Yang,Shaochun Tang,Duan Bin,Xiangkang Meng,Hongbin Lu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

Stainless steel (SS) is a promising material for designing bipolar plates (BPs), but their further applicationis limited by serious corrosion problems in the acidic environment. Ti3C2Tx is expected to be used for SSBPs coatings, while galvanic corrosion will occur after the damage of Ti3C2Tx coating. Herein, a PPY/Ti3C2Tx-AE double-layer coating (DC) is well-designed and prepared on 304SS BP, which is composedof an inner electropolymerized PPY layer and an outer Ti3C2Tx-acrylic epoxy layer. When tested in0.2 M HCl solution, the corrosion potential and corrosion current density of the DC are 38 mV and0.00927 lA cm2 respectively, which are superior to those of the PPY coating and the Ti3C2Tx coating. Moreover, the DC presents the best long-term stability among the three coatings. The excellent corrosionresistance is attributed to the barrier and anodic protection effects as well as the solution of galvanic corrosion. The new coating system provides a new insight into the design of DC coatings of SS BPs.

Carbon Nanotube Paper as Anode for Flexible Lithium-Ion Battery

Xiaogang Sun,Zhenhong Liu,Neng Li,Xiaoyong Wu,Yanyan Nie,Zhipeng Pang,Lifu Yue,Hao Tang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.11

In this investigation, multiwalled carbon nanotube (MWCNT) paper consists of MWCNTs and cellulose was fabricated by traditional paper-making method. It was applied directly as negative electrode in flexible lithium ion battery to replace ordinary electrode which is combined with anode material and current collector. The electrochemical performances of the as-produced MWCNT paper (AMP) and carbonized MWCNT paper (CMP) were evaluated in this study. The morphology and structure of the MWCNT papers were observed by scanning electron microscopy (SEM). The electrochemical performance of the battery was operated by cell test and electrochemical impedance spectroscopy (EIS) measurement. The charging and discharging results indicated that the CMP behaves with higher capacity than AMP. And the EIS analysis showed that a lower charge transfer resistance can be obtained in the CMP. The excellent electrochemical performance verifies the feasibility of MWCNT papers as a promising candidate for the anode in flexible lithium ion battery.