Huazhong University of Science and Technology

About: Huazhong University of Science and Technology is a education organization based out in Wuhan, China. It is known for research contribution in the topics: Population & Computer science. The organization has 120339 authors who have published 122521 publications receiving 2168040 citations. The organization is also known as: Central China University of Science and Technology.

From graphite to graphene: direct liquid-phase exfoliation of graphite to produce single- and few-layered pristine graphene

Abstract: Graphene, a two-dimensional crystalline form of carbon, has attracted wide and intense interest owing to its excellent physical properties and because its surface and edges can be chemically modified readily. Development of a method for producing high-quality graphene in large quantities is essential for further investigation of its properties and applications. The direct liquid-phase exfoliation of graphite to produce graphene is a convenient method for generating ideal graphene samples in large quantities. This direct method, which involves the use of colloidal suspensions, is based on the one-step physical transformation of graphite into graphene and has many unique advantages. A large number of liquids have been employed as exfoliation media and show a range of exfoliation efficiencies. In this review, we highlight the recent progress made on the exfoliation of bulky graphite powders or flakes into single- and few-layered graphene sheets in various liquids, including organic solvents, ionic liquids, and water/surfactant solutions. The qualities and yields of the exfoliated graphene samples, as well as their use in various applications, are also reviewed. Furthermore, future research directions for the development of novel exfoliation media and more efficient techniques for producing well-exfoliated pristine graphene are proposed.

Modeling of VSC Connected to Weak Grid for Stability Analysis of DC-Link Voltage Control

Abstract: In this paper, a small-signal model of voltage source converter (VSC) is developed to investigate the stability of dc-link voltage control. This model contributes to representing the dc-link voltage dynamics characteristics of VSC integrated to weak grid. Effects of grid strength, operating point, and control loops’ interactions on the performance of VSC are taken into consideration. Based on the proposed small-signal model, eigenvalue analysis is employed to study the stability of dc-link voltage control with varying operating conditions. Analysis results show that control loops’ interactions introduce a partial positive feedback to the dc-link voltage control in weak grid. Furthermore, the effect of control loops’ interactions on dc-link voltage control stability reaches largest when the bandwidth of the phase-locked loop is close to that of the dc-link voltage control. Time-domain simulations and experiments were conducted to validate the analysis.

Template-free synthesis of hollow-structured Co3O4 nanoparticles as high-performance anodes for lithium-ion batteries.

Abstract: We have developed a template-free procedure to synthesize Co3O4 hollow-structured nanoparticles on a Vulcan XC-72 carbon support. The material was synthesized via an impregnation–reduction method followed by air oxidation. In contrast to spherical particles, the hollow-structured Co3O4 nanoparticles exhibited excellent lithium storage capacity, rate capability, and cycling stability when used as the anode material in lithium-ion batteries. Electrochemical testing showed that the hollow-structured Co3O4 particles delivered a stable reversible capacity of about 880 mAh/g (near the theoretical capacity of 890 mAh/g) at a current density of 50 mA/g after 50 cycles. The superior electrochemical performance is attributed to its unique hollow structure, which combines nano- and microscale properties that facilitate electron transfer and enhance structural robustness.

Differential roles of ERK and Akt pathways in regulation of EGFR-mediated signaling and motility in prostate cancer cells.

Abstract: Upregulation of epidermal growth factor receptor (EGFR) and subsequent increases in extracellular-regulated kinase (ERK) and Akt signaling are implicated in prostate cancer progression Impaired endocytic downregulation of EGFR also contributes to oncogenic phenotypes such as metastasis Thus, understanding the roles of divergent signaling pathways in the regulation of EGFR trafficking and EGFR-driven invasive migration may enable the development of more effective therapies In this study, we use the human prostate cancer cell lines, DU145 and PC3, to investigate the effects of both the ERK and Akt pathways on epidermal growth factor (EGF)-mediated EGFR signaling, trafficking and cell motility We show that DU145 and PC3 cells overexpress EGFR and migrate in a ligand (EGF)-dependent manner Next, we show that pharmacological inhibition of ERK (but not Akt) signaling enhances EGF-induced EGFR activation, ubiquitination and downregulation, and may lead to enhanced receptor turnover These findings negatively correlate with ERK-mediated threonine phosphorylation of EGFR, implicating it as a possible mechanism Further, we uncover that EGF promotes disassembly of cell-cell junctions, downregulation of E-cadherin and upregulation of the transcriptional repressor, Snail, typical characteristics of epithelial-mesenchymal transition (EMT) These effects are dependent on activation of Akt, as inhibition of Akt signaling abolishes EGF/EGFR-driven cell migration and EMT Knockdown of endogenous Snail also prevents EGFR-mediated downregulation of E-cadherin, EMT and cell migration Surprisingly, inhibition of the ERK pathway augments EGFR-dependent motility, occurring concomitantly with elevation of EGF-induced Akt activity Collectively, our results suggest that EGF-triggered ERK activation has profound feedback on EGFR signaling and trafficking by EGFR threonine phosphorylation, and Akt has a pivotal role in EGFR-mediated cell migration by activating EMT More important, our results also suggest that therapeutic targeting of ERK signaling may have undesirable outcomes (for example, augmenting EGFR-driven motility)