Effect of Texture and Microstructure on Tensile Behaviors in the Polycrystalline Pure Niobium

Shanshan Zhang,Yuancai Liu,Tiewei Xu,Mingxue Sun,Qi Zhang,Yong Wan 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

Pure polycrystalline niobium had different texture and microstructure due to the RCD-60, RCD-84 and CD-84 fabricationprocesses and recrystallization at 1000 °C for 2 h. The tensile behaviors and texture evolutions of the niobium were investigatedto reveal the correlation of initial texture/microstructure and tensile properties. The crucial differences of microstructureand orientations after recrystallization would influence tensile properties of the niobium. The differences of tensile behaviorsduring tension testing correspond to the different microstructure and texture evolution in the niobium. The enhanced ⟨110⟩ //RD texture during the tensile deformation indicates that orientations of sub-structures are arranging along the tensile axis inthe RCD-60 niobium. The RCD-84 and CD-84 niobium present the other phenomenon, that sub-structures near the fractureoccur a significant rotation and the ⟨110⟩ // RD texture has been slightly changed after tensile failure. The recrystallizedniobium fabricated by the RCD-84 obtains excellent tensile properties with ultimate tensile strength of 364 MPa and elongationof 55%. The strain hardening rate of the CD-84 niobium is the highest during the initial stage of tensile deformation,and becomes lower than that of the RCD-84 niobium after the 16% strain. Furthermore, the analysis of Taylor factors isapplied to reveal the difference of hardening rates during tensile deformation due to different fabrication and recrystallizationprocesses of the polycrystalline niobium.

Facile synthesis of novel ZnFe2O4/CdS nanorods composites and its efficient photocatalytic reduction of Cr(VI) under visible-light irradiation

Shanshan Fang,Yawen Zhou,Man Zhou,ZHONGYU LI,SONG XU,Chao Yao 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.58 No.-

ZnFe2O4/CdS composites were successfully prepared by a facile process. The obtained samples have beencharacterized by X-ray diffraction (XRD), scanning electron microscopy (FE-SEM), transmission electronmicroscopy (TEM), diffuse reflection spectroscopy (DRS), Raman spectroscopy and photoluminescence(PL). Under visible light irradiation, ZnFe2O4/CdS composite shows higher photocatalytic activity in the Cr(VI) reduction, relative to the pure CdS and ZnFe2O4. The enhanced photocatalytic performance wasascribed to the intimate contact interfaces and matching band potentials between CdS and ZnFe2O4, andcan be related to the efficient transfer and separation of the electron-hole pairs. It was found that themodification of ZnFe2O4 did not affect the morphology of CdS. The result of PL test indicated a lowerintensity, and effective separation of photogenerated electron-hole pairs. In addition, the ZnFe2O4/CdScomposites showed more intense optical absorption than that of pure CdS and ZnFe2O4. Through theanalysis of experiment results, a reasonable photocatalytic mechanism over ZnFe2O4/CdS photocatalystswas also proposed.

A brain somatic RHEB doublet mutation causes focal cortical dysplasia type II

Shanshan Zhao,Zhenghui Li,Muxian Zhang,Lingliang Zhang,Honghua Zheng,Jinhuan Ning,Yanyan Wang,Feng-Peng Wang,Xiaobin Zhang,Hexia Gan,Yuanqing Wang,Xian Zhang,Hong Luo,Guojun Bu,Huaxi Xu,Yi Yao,Yun-wu 생화학분자생물학회 2019 Experimental and molecular medicine Vol.51 No.-

Focal cortical dysplasia type II (FCDII) is a cerebral cortex malformation characterized by local cortical structure disorganization, neuronal dysmorphology, and refractory epilepsy. Brain somatic mutations in several genes involved in the PI3K/AKT/mTOR pathway are associated with FCDII, but they are only found in a proportion of patients with FCDII. The genetic causes underlying the development FCDII in other patients remain unclear. Here, we carried out whole exome sequencing and targeted sequencing in paired brain–blood DNA from patients with FCDII and identified a brain somatic doublet mutation c.(A104T, C105A) in the Ras homolog, mTORC1 binding (RHEB) gene, which led to the RHEB p.Y35L mutation in one patient with FCDII. This RHEB mutation carrier had a dramatic increase of ribosomal protein S6 phosphorylation, indicating mTOR activation in the region of the brain lesion. The RHEB p.Y35L mutant protein had increased GTPλS-binding activity compared with wild-type RHEB. Overexpression of the RHEB p. Y35L variant in cultured cells also resulted in elevated S6 phosphorylation compared to wild-type RHEB. Importantly, in utero electroporation of the RHEB p.Y35L variant in mice induced S6 phosphorylation, cytomegalic neurons, dysregulated neuron migration, abnormal electroencephalogram, and seizures, all of which are found in patients with FCDII. Rapamycin treatment rescued abnormal electroencephalograms and alleviated seizures in these mice. These results demonstrate that brain somatic mutations in RHEB are also responsible for the pathogenesis of FCDII, indicating that aberrant activation of mTOR signaling is a primary driver and potential drug target for FCDII.

Construction of Bacillus subtilis strain engineered for expression of porcine β-defensin-2/cecropin P1 fusion antimicrobial peptides and its growth-promoting effect and antimicrobial activity

Jian Xu,Fei Zhong,Yonghong Zhang,Jianlou Zhang,Shanshan Huo,Hongyu Lin,Liyue Wang,Dan Cui,Xiujin Li 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.4

Objective: To generate recombinant Bacillus subtilis (B. subtilis) engineered for expression of porcine β-defensin-2 (pBD-2) and cecropin P1 (CP1) fusion antimicrobial peptide and investigate their anti-bacterial activity in vitro and their growth-promoting and disease resisting activity in vivo. Methods: The pBD-2 and CP1 fused gene was synthesized using the main codons of B. subtilis and inserted into plasmid pMK4 vector to construct their expression vector. The fusion peptide-expressing B. subtilis was constructed by transformation with the vector. The expressed fusion peptide was detected with Western blot. The antimicrobial activity of the expressed fusion peptide and the recovered pBD-2 and CP1 by enterokinase digestion in vitro was analyzed by the bacterial growth-inhibitory activity assay. To analyze the engineered B. subtilis on growth promotion and disease resistance, the weaned piglets were fed with basic diet supplemented with the recombinant B. subtilis. Then the piglets were challenged by enteropathogenic Escherichia coli (E. coli). The weight gain and diarrhea incidence of piglets were measured after challenge. Results: The recombinant B. subtilis engineered for expression of pBD-2/CP1 fusion peptide was successfully constructed using the main codons of the B. subtilis. Both expressed pBD-2/CP1 fusion peptide and their individual peptides recovered from parental fusion peptide by enterokinase digestion possessed the antimicrobial activities to a variety of the bacteria, including gram-negative bacteria (E. coli, Salmonella typhimurium, and Haemophilus parasuis) and gram-positive bacteria (Staphylococcus aureus). Supplementing the engineered B. subtilis to the pig feed could significantly promote the piglet growth and reduced diarrhea incidence of the piglets. Conclusion: The generated B. subtilis strain can efficiently express pBD-2/CP1 fusion antimicrobial peptide, the recovered pBD-2 and CP1 peptides possess potent antimicrobial activities to a variety of bacterial species in vitro. Supplementation of the engineered B. subtilis in pig feed obviously promote piglet growth and resistance to the colibacillosis.

Ultrafast Channel II process induced by a 3-D texture with enhanced acceptor order ranges for high-performance non-fullerene polymer solar cells

Chen, Shanshan,Lee, Sang Myeon,Xu, Jianqiu,Lee, Jungho,Lee, Kyu Cheol,Hou, Tianyu,Yang, Yankang,Jeong, Mingyu,Lee, Byongkyu,Cho, Yongjoon,Jung, Sungwoo,Oh, Jiyeon,Zhang, Zhi-Guo,Zhang, Chunfeng,Xiao, The Royal Society of Chemistry 2018 ENERGY AND ENVIRONMENTAL SCIENCE Vol.11 No.9

<P>To achieve efficient non-fullerene polymer solar cells (NF-PSCs), an in-depth understanding of the key properties that govern the power output is necessary. Herein, three trialkylsilyl substituted benzodithiophene-based polymer donors (PJ1, PJ2, and PJ3) were synthesized with fine-tuning of the highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) and optical absorption. Using the polymer series paired with absorption-complementary small molecular acceptors (SMAs), namely, <I>m</I>-ITIC, IDIC, and AIDIC, we systematically studied the performance of a 3 × 3 matrix of NF-PSCs. An increasing open-circuit voltage with deepening HOMOs of the polymer donors, and the enhanced short-circuit current (<I>J</I>SC) and fill factor (FF) were ascribed to the well-intermixed blend morphology containing enhanced SMA order ranges with mixed face-on and edge-on orientations, the so-called 3-D texture. Such an optimal microstructure is best exemplified in the PJ2:IDIC combination, affording a highest efficiency of 12.01% with a simultaneously high <I>J</I>SC of 17.0 mA cm<SUP>−2</SUP> and FF of 75.3%. The devices with an active layer thickness of 300 nm still maintain an impressive efficiency approaching 10% with a decent FF of 60.0%. Moreover, the Channel II process, <I>i.e.</I>, photoinduced hole transfer through acceptor excitation, was demonstrated to be crucially important for photocurrent generation. This study highlights the importance of optimizing the trade-off between charge separation/transport and domain size to achieve high-performance NF-PSCs.</P>

THE SUITABILITY OF MITOCHONDRIAL AND MICROSATELLITE DNA AS GENETIC TAGS TO ASSESS STOCK ENHANCEMENT OF Portunus trituberculatus

Shengyong Xu,Shanshan Cai,Xiumei Zhang,Ming Liu,Na Song,Jun Wang,Tianxiang Gao 한국수산과학회 양식분과 2015 한국수산과학회 양식분과 학술대회 Vol.2015 No.5

Birch-Type Hydrogenation of Few-Layer Graphenes: Products and Mechanistic Implications

Zhang, Xu,Huang, Yuan,Chen, Shanshan,Kim, Na Yeon,Kim, Wontaek,Schilter, David,Biswal, Mandakini,Li, Baowen,Lee, Zonghoon,Ryu, Sunmin,Bielawski, Christopher W.,Bacsa, Wolfgang S.,Ruoff, Rodney S. American Chemical Society 2016 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.138 No.45

<P>Few-layer graphenes, supported on Si with a superficial oxide layer, were subjected to a Birch-type reduction using Li and H2O as the electron and proton donors, respectively. The extent of hydrogenation for bilayer graphene was estimated at 1.6-24.1% according to Raman and X-ray photoelectron spectroscopic data. While single-layer graphene reacts uniformly, few-layer graphenes were hydrogenated inward from the edges and/or defects. The role of these reactive sites was reflected in the inertness of pristine few-layer graphenes whose edges were sealed. Hydrogenation of labeled bilayer (C-12/C-13) and trilayer (C-12/C-13/C-12) graphenes afforded products whose sheets were hydrogenated to the same extent, implicating passage of reagents between the graphene layers and equal decoration of each graphene face. The reduction of few-layer graphenes introduces strain, allows tuning of optical transmission and fluorescence, and opens synthetic routes to long sought-after films containing sp(3)-hybridized carbon.</P>

Preparation and In Vitro Evaluation of Povidone-Sodium Cholate- Phospholipid Mixed Micelles for the Solubilization of Poorly Soluble Drugs

Yuan Zhu,Shanshan Tong,Li Wang,Min Peng,Xia Cao,Ximing Xu,Jiangnan Yu 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.6

Mixed micelles made of polyvinylpyrrolidone (PVP), sodium cholate, and phospholipids were prepared to improve the solubility of poorly water-soluble drugs. Sylibin, a drug used in treating liver diseases, was incorporated into the mixed micelles. The formulation of sylibin containing PVP-sodium cholate-phospholipid mixed micelles with an optimized composition (PVP/sodium cholate/phospholipid/silybin = 3:3:4:1~2 by weight) was obtained based on the study of pseudoternary phase diagrams. The critical micelle concentration was used to evaluate the micellar stability towards dilution. The results showed that addition of PVP to sodium-cholate-phospholipid mixed micelles increased stability. The solubility of sylibin in PVP-sodium cholate-phospholipid mixed micelles was higher than that in pure water or in sodium cholate-phospholipid mixed micelles. In a stability study, we found that PVP-sodium cholate-phospholipid mixed micelles showed good stability. After 3 months storage at 40oC, just 2.6% sylibin was lost with only minor changes of the particle size when compared to a reference formulation containing sodium cholate and phospholipid mixed micelles. In addition, the developed formulation significantly improved in vitro drug release. The time required to release 50% sylibin (t50%) from sodium cholate and phospholipid mixed micelles was 326 h, while the t50% from PVP-sodium cholate-phospholipid mixed micelles was only 51.1 h. Our results suggest that these mixed micelles might have significant potential application to the biomedical field.

Control Strategy for an Electromechanical Transmission Vehicle Based on a Double Markov Process

Liu Hui,Xu Riming,Han Lijin,Xiong Shanshan 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.3

Based on an analysis of the driving demand and system dynamics of heavy-duty vehicles equipped with electromechanical transmission (EMT), a double Markov model is put forward to represent drivers’ power demand for driving and electricity. Transfer probability matrices are calculated by utilizing the maximum likelihood estimation method. A power distribution control strategy based on stochastic dynamic programming (SDP) is proposed. With economy being the optimization goal, the model for power allocation control based on SDP is established while regarding the engine torque, motor speeds, vehicle speed and state of charge (SOC) as state variables’ engine speed and motor torques as control variables’ and power demands as interference variables. The SDP problem is solved by an improved policy iteration algorithm based on value iteration and policy iteration algorithms.

FPGA-Based Real-Time System for Demodulating FBG Wavelength

Peng Wang,Minglei Shao,Xu Han,Shanshan Li 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.6

In order to detect the wavelength drift of FBG (fiber Bragg grating) sensors, the real-time demodulating system based on tunable F-P filter (TFPF) was built. The optical parts of the demodulation system include broadband optical source, TFPF unit, reference grating model, sensing grating array, and couplers. The electronic parts of the demodulation system consist of AD converting unit, DA converting unit, field programmable gate array (FPGA) unit and human-computer interaction unit. With the high-speed data processing capacity, FPGA was utilized to realize digital logic circuits of the demodulation system. It includes resetting unit, phase locked loop (PLL) unit, driving TFPF unit, detecting keys unit, LCD displaying unit, FIR filtering unit and data calculating unit. The demodulating system has such features as high reliability and speed, instantaneity, and programmability. It can satisfy the requirements of wavelength demodulation of FBG sensors in practical engineering.