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Yang Weiwei 한국콘텐츠학회 2011 ICCC International Digital Design Invitation Exhib Vol.2011 No.5

First‑Principles Study of Black Phosphorus as Anode Material for Rechargeable Potassium‑Ion Batteries

Weiwei Yang,Yunxiang Lu,Chengxi Zhao,Honglai Liu 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.1

In two-dimensional materials, black phosphorus has shown excellent performance as electrode materials for lithium- and sodium-ion batteries, due to its thermodynamic stability, layered anisotropic structure, and electrical conductivity. Recently, high capacity anodes based on black phosphorus as an active component for potassium-ion batteries (PIBs) have also been reported. However, in-depth studies are required to clarify the adsorption and difusion of K ions on black phosphorus and the K–P reaction mechanism. In this work, the surface adsorption, bulk difusion, and K–P binary phase formation were frstly investigated in detail using frst-principle calculations. We found that compared with Li and Na, K has the lowest difusion energy barrier in the bulk phase (0.182 eV for zigzag type and 2.013 eV for armchair type). Black phosphorus structure irreversibly collapses when the K ion concentration is up to 0.625, and no K3P phase is formed through the electrochemical profles obtained by calculation of the binary phase alloy structures. Furthermore, the maximum capacitance of black phosphorous for PIBs is calculated to be 864.8 mAh.g−1. This work will help in understanding the mechanism and further improving the performance of K-ion batteries.

The Intrinsic Relation between the Hydrogel Structure and In Vivo Performance of Hyaluronic Acid Dermal Fillers: A Comparative Study of Four Typical Dermal Fillers

Zhou Weiwei,Hou Shuai,Deng Shu,Peng Yang,Fu Wei,Zhou Yang,Yang Jie,Peng Cheng 한국조직공학과 재생의학회 2023 조직공학과 재생의학 Vol.20 No.3

BACKGROUND: Hyaluronic acid dermal fillers are composed of cross-linked viscoelastic particles with high biocompatibility. The performance of the fillers is determined by the viscoelastic properties of particles and the connecting force between particles. However, the relationships among the properties of fillers, the interaction of the gels and the surrounding tissue are not clear enough. METHOD: Four kinds of typical dermal filler were selected in this research to reveal the interaction between the gels and cells. A series of analytical tools was applied to characterize the structure and physicochemical properties of the gel, as well as observing their interaction with the surrounding tissues in vivo and discussing their internal mechanism. RESULT: The large particles internal the gel and the high rheological properties endow the Restylane2 with excellent support. However, these large-size particles have a significant impact on the metabolism of the local tissue surrounding the gel. Juve´derm3 present gel integrity with the high cohesiveness and superior support. The rational matching of large and small particles provides the Juve´derm3 with supporting capacity and excellent biological performance. Ifresh is characterized by small-size particles, moderate cohesiveness, good integrity, lower viscoelasticity and the superior cellular activity located the surrounding tissues. Cryohyaluron has high cohesion and medium particle size and it is prominent in cell behaviors involving localized tissues. Specific macroporous structure in the gel may facilitate the nutrients delivering and removing the waste. CONCLUSION: It’s necessary to make the filler both sufficient support and biocompatibility through the rational matching of particle sizes and rheological properties. Gels with macroporous structured particle showed an advantage in this area by providing a space inside the particle.

A quantitative assessment method of network information security vulnerability detection risk based on the meta feature system of network security data

( Weiwei Lin ),( Chaofan Yang ),( Zeqing Zhang ),( Xingsi Xue ),( Reiko Haga ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.12

Because the traditional network information security vulnerability risk assessment method does not set the weight, it is easy for security personnel to fail to evaluate the value of information security vulnerability risk according to the calculation value of network centrality, resulting in poor evaluation effect. Therefore, based on the network security data element feature system, this study designed a quantitative assessment method of network information security vulnerability detection risk under single transmission state. In the case of single transmission state, the multi-dimensional analysis of network information security vulnerability is carried out by using the analysis model. On this basis, the weight is set, and the intrinsic attribute value of information security vulnerability is quantified by using the qualitative method. In order to comprehensively evaluate information security vulnerability, the efficacy coefficient method is used to transform information security vulnerability associated risk, and the information security vulnerability risk value is obtained, so as to realize the quantitative evaluation of network information security vulnerability detection under single transmission state. The calculated values of network centrality of the traditional method and the proposed method are tested respectively, and the evaluation of the two methods is evaluated according to the calculated results. The experimental results show that the proposed method can be used to calculate the network centrality value in the complex information security vulnerability space network, and the output evaluation result has a high signal-to-noise ratio, and the evaluation effect is obviously better than the traditional method.

Long Carbon Fibers Reinforced Rigid Polyurethane Composites: An Investigation In Strength and Toughness

Weiwei Li,Jie Yang,Xiaojing Liu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7

High-performance polyurethane materials are attracting more and more attention. In this work, a cooperativeimprovement of strength and toughness of rigid polyurethane (RPU) composites was achieved. 1.0 wt% long carbon fibers(LCFs) reinforced RPU composites were prepared and the effects of fiber oxidation treatment were studied. The resultsindicated that the surface roughness and wettability of LCFs were both increased, which could provide better physicalbonding between LCFs and RPU matrix. Moreover, the increasing -OH groups on the fiber surface would react with RPU toform chemical bond. With the strengthened physical and chemical bonds, the interface of LCFs/RPU composites has beeneffectively improved. The mechanical properties showed that compared with pure RPU, the tensile strength, tensile modulus,bending strength, bending modulus, and impact strength of oxidized LCFs/RPU composites were increased by 171.1 %,814.3 %, 29.1 %, 125.8 % and 110.1 %, respectively. Interlaminar shear strength (ILSS) was also increased by 65.1 %. Dynamic thermomechanical analysis (DMA) and scanning electron microscope (SEM) indicated the positive effects of theoxidation treatment on the interfacial bonding between LCFs and RPU matrix.

Neferine increase in vitro anticancer effect of dehydroepiandrosterone on MCF-7 human breast cancer cells

Yang, Dingyi,Zou, Xiaochuan,Yi, Ruokun,Liu, Weiwei,Peng, Deguang,Zhao, Xin The Korean Society for Applied Biological Chemistr 2016 Applied Biological Chemistry (Appl Biol Chem) Vol.59 No.4

This study was conducted to investigate the in vitro anticancer reinforcing effects of neferine (Nef) on dehydroepiandrosterone (DHEA) and the mechanism was also determined during the investigation. By the growth effects of Nef and DHEA on MCF-7 human breast cancer cells, 8 mg/mL Nef was a non-virulent concentration in MCF-7 cells, and this concentration was used for further experiment. In 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide assay, 30 mg/mL DHEA showed 49.4 % growth inhibitory effect in MCF-7 cells, whereas Nef (8 mg/mL) + DHEA (30 mg/mL) treatment had the higher effect at 67.8 %. The flow cytometry analysis results showed that 15 and 30 mg/mL DHEA-treated MCF-7 cells had 12.2 and 21.6 % apoptotic cells, respectively, Nef + DHEA could raise the apoptotic cells to 36.7 %. Reverse transcription-polymerase chain reaction assay shows remarkable results according to which DHEA could significantly increase caspase-3, caspase-8, caspase-9, Bax, p53, p21, E2F1, Fas, FasL mRNA expressions and decrease Bcl-2, Bcl-xL, HIAP-1, HIAP-2, survivin expressions as compared to the untreated control cancer cells. Moreover, these effects depend on the concentration of DHEA, and Nef which could further strengthen these effects. From these results, low concentration of Nef could not influence the growth of MCF-7 cells, but using its sensitization effect, Nef raised the in vitro effects of DHEA. Nef could be got easily. With these results we can accomplish that Nef + DHEA might be used as the new anticancer materials combination.

Electrospun Fibrous Silk Fibroin/Poly(L-Lactic Acid) Scaffold for Cartilage Tissue Engineering

Weiwei Liu,Zhengqiang Li,Lu Zheng,Xiaoyan Zhang,Peng Liu,Ting Yang,Bing Han 한국조직공학과 재생의학회 2016 조직공학과 재생의학 Vol.13 No.5

For successful tissue engineering of articular cartilage, a scaffold with mechanical properties that match those of natural cartilage as closely as possible is needed. In the present study, we prepared a fibrous silk fibroin (SF)/poly(L-lactic acid) (PLLA) scaffold via electrospinning and investigated the morphological, mechanical, and degradation properties of the scaffolds fabricated using different electrospinning conditions, including collection distance, working voltage, and the SF:PLLA mass ratio. In addition, in vitro cell-scaffold interactions were evaluated in terms of chondrocyte adhesion to the scaffolds as well as the cytotoxicity and cytocompatibility of the scaffolds. The optimum electrospinning conditions for generating a fibrous SF/PLLA scaffold with the best surface morphology (ordered alignment and suitable diameter) and tensile strength (~1.5 MPa) were a collection distance of 20 cm, a working voltage of 15 kV, and a SF:PLLA mass ratio of S50P50. The degradation rate of the SF/PLLA scaffolds was found to be determined by the SF:PLLA mass ratio, and it could be increased by reducing the PLLA proportion. Furthermore, chondrocytes spread well on the fibrous SF/PLLA scaffolds and secreted extracellular matrix, indicating good adhesion to the scaffold. The cytotoxicity of SF/PLLA scaffold extract to chondrocytes over 24 and 48 h in culture was low, indicating that the SF/PLLA scaffolds are biocompatible. Chondrocytes grew well on the SF/PLLA scaffold after 1, 3, 5, and 7 days of direct contact, indicating the good cytocompatibility of the scaffold. These results demonstrate that the fibrous SF/PLLA scaffold represents a promising composite material for use in cartilage tissue engineering.

Steering Coacervation by a Pair of Broad-Spectrum Regulators

Yang, Shenyu,Li, Bo,Wu, Chunxian,Xu, Weiwei,Tu, Mei,Yan, Yun,Huang, Jianbin,Drechsler, Markus,Granick, Steve,Jiang, Lingxiang American Chemical Society 2019 ACS NANO Vol.13 No.2

<P>Coacervation is liquid-liquid phase separation ubiquitous in industrial applications and cellular biology. Inspired by cellular manipulation of coacervate droplets such as P granules, we report here a regulatory strategy to manipulate synthetic coacervation in a spatiotemporally controllable manner. Two oppositely charged small molecules are shown to phase separate into coacervate droplets in water as a result of electrostatic attraction, hydrophobic effect, and entropy. We identify a down regulator, β-cyclodextrin, to disrupt the hydrophobic effect, thus dissolving the droplets, and an up regulator, amylase, to decompose β-cyclodextrin, thus restoring the droplets. The regulation kinetics is followed in real time on a single-droplet level, revealing diffusion-limited dissolution and reaction-limited condensation, respectively, taking ∼4 s and 2-3 min. Versatility of this strategy to manipulate the coacervation is demonstrated in two aspects: spatially distributed coacervation in virtue of amylase-grafted hydrogel frameworks and coacervate transportation across membranes and hydrogel networks <I>via</I> a disassemble-to-pass strategy. The current regulatory pairs and strategies are anticipated to be general for a wide variety of synthetic self-assembly systems.</P> [FIG OMISSION]</BR>

Computational Bio-Fluid Mechanics

Yang Liu,Weiwei Yan,Mingzhen Lu,Bingmei Fu 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.10

It has been found that both circulating blood cells and tumor cells are more easily adherent to curved microvessels than straight ones. In this paper, the hypothesis that tumor cells prefer to adhere at the microvessels with localized shear stresses and their gradients, such as in the curved microvessels, was examined both experimentally and computationally. The fluid dynamics was carried out by the lattice Boltzmann method (LBM), and the cell dynamics was governed by the Newton’s law of translation and rotation. The adhesive dynamics model is involved the effect of receptor-ligand bonds between circulating cells and endothelial cells (ECs). It was found that the wall shear stress/gradient, over a threshold, had significant contribution to tumor cell adhesion by activating or inactivating cell adhesion molecules. Our results elucidated why the tumor cell adhesion prefers to occur at the positive curvature of curved microvessels with very low Reynolds number (in the order of 10<SUP>-2</SUP>) laminar flow. Obstructive sleep apnea (OSA) is a common disorder characterized by partial or complete narrowing of the pharyngeal airway during sleep. The success rate of OSA surgery is very low, CFD is a good alternative tool to understand OSA pathophysiology. We have carried out both LES simulation and experimental measurement in real OSA upper airways for both before and after surgery, and a good agreement is achieved.

Electric-Field-Induced Dispersion of Multiwalled Carbon Nanotubes in Nematic Liquid Crystal

Tie, Weiwei,Yang, Gyu Hyung,Bhattacharyya, Surjya Sarathi,Lee, Young Hee,Lee, Seung Hee American Chemical Society 2011 The Journal of Physical Chemistry Part C Vol. No.

<P>Effect of electric field and frequency on multiwalled carbon nanotubes (MWCNTs) dispersion in liquid crystal (LC) medium has been investigated. At zero field, large MWCNT aggregates are found due to insufficient dispersion throughout the cell under optical microscopy. As the vertical field strength increases gradually, the cluster sizes become smaller, and at above critical field strength, the clusters disappear and are dispersed finally into LC medium. The dispersion of CNT clusters remained stable even after the field is removed. Strong correlation of cluster sizes with field strength was also observed. The dispersion of clusters at above critical field was also confirmed by the light absorption. This robustness of field-induced dispersion of CNTs provides a new method of improving solubility of CNTs in LC medium, which can be advantageous in numerous CNT-LC optoelectronic devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2011/jpccck.2011.115.issue-44/jp206961a/production/images/medium/jp-2011-06961a_0006.gif'></P>