Experimental Study and Degradation Analysis on Interfacial Shear Modulus of Steel and Steel Fiber-Reinforced Concrete Composite Structure

Kai Wu,Shiyuan Qian,Huiming Zheng,Yukai Zhou,Fangzhou Guo 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8

To address the problems of mutual interference between shaped steel and reinforcement bars and the difficulty of concrete pouring in the construction of steel-reinforced concrete (SRC) composite structure, the steel and steel fiber-reinforced concrete (SSFRC) composite structure without rebars was proposed. Bond behavior between the shaped steel and steel fiber reinforced concrete is the basis to ensure two kinds of materials work together. 20 square specimens were designed and tested by push-out test to study the bond performance and shear modulus of the interface between the shaped steel and steel fiber reinforced concrete. The effects of steel fiber ratio (ρsf), embedded length (Le), and concrete cover thickness (Css) on the interfacial shear modulus (G) were analyzed quantitatively. The degradation law of G was studied by defining the degradation variable of interfacial shear modulus (Da). The results show that the increase of ρsf contributes to the ascent in G, and the loading end displacement (D) at the end of degradation related to G also increase. With the rise of Le, the value of Gdecreases gradually and the D becomes larger when G starts to deteriorate. In addition, there is a positive correlation between G and Css. Besides, the higher Css leads to a slower degradation process of G.

Interfacial bond properties and comparison of various interfacial bond stress calculation methods of steel and steel fiber reinforced concrete

Kai Wu,Huiming Zheng,Junfu Lin,Hui Li,Jixiang Zhao 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.6

Due to the construction difficulties of steel reinforced concrete (SRC), a new composite structure of steel and steel fiber reinforced concrete (SSFRC) is proposed for solving construction problems of SRC. This paper aims to investigate the bond properties and composition of interfacial bond stress between steel and steel fiber reinforced concrete. Considering the design parameters of section type, steel fiber ratio, interface embedded length and concrete cover thickness, a total of 36 specimens were fabricated. The bond properties of specimens were studied, and three different methods of calculating interfacial bond stress were analyzed. The results show: relative slip first occurs at the free end; Bearing capacity of specimens increases with the increase of interface embedded length. While the larger interface embedded length is, the smaller the average bond strength is. The average bond strength increases with the increase of concrete cover thickness and steel fiber ratio. And calculation method 3 proposed in this paper can not only reasonably explain the hardening stage after the loading end curve yielding, but also can be applied to steel reinforced high-strength concrete (SRHC) and steel reinforced recycled coarse aggregate concrete (SRRAC).

Highly efficient hydrogen evolution catalysis based on MoS₂/CdS/TiO₂ porous composites

Du, Jimin,Wang, Huiming,Yang, Mengke,Zhang, Fangfang,Wu, Haoran,Cheng, Xuechun,Yuan, Sijie,Zhang, Bing,Li, Kaidi,Wang, Yina,Lee, Hyoyoung Elsevier 2018 International journal of hydrogen energy Vol.43 No.19

<P><B>Abstract</B></P> <P>Efficient production of hydrogen through visible-light-driven water splitting mechanism using semiconductor-based composites has been identified as a promising strategy for converting light into clean H<SUB>2</SUB> fuel. However, researchers are facing lots of challenges such as light absorption and electron-hole pair recombination and so on. Here, new sheet-shaped MoS<SUB>2</SUB> and pyramid-shaped CdS <I>in-situ</I> co-grown on porous TiO<SUB>2</SUB> photocatalysts (MoS<SUB>2</SUB> CdSTiO<SUB>2</SUB>) are successfully obtained <I>via</I> mild sulfuration of MoO<SUB>3</SUB> and CdO coexisted inside porous TiO<SUB>2</SUB> monolith by a hydrothermal route. The scanning electron microscopy and transmission electron microscopy results exhibit that the MoS<SUB>2</SUB> CdSTiO<SUB>2</SUB> composites have average pore size about 500 nm. The 3%MoS<SUB>2</SUB> 10%CdSTiO<SUB>2</SUB> demonstrated excellent photocatalytic activity and high stability for a hydrogen production with a high H<SUB>2</SUB>-generation rate of 4146 μmol h<SUP>−1</SUP> g<SUP>−1</SUP> under visible light irradiation even without noble-metal co-catalysts. The super photocatalytic performance of the visible-light-driven hydrogen evolution is predominantly attributed to the synergistic effect. The conduction band of MoS<SUB>2</SUB> facilitates in transporting excited electrons from visible-light on CdS to the porous TiO<SUB>2</SUB> for catalytic hydrogen production, and holes to MoS<SUB>2</SUB> for inhibiting the photocorrosion of CdS, respectively, leading to enhancing the efficient separation of electrons and holes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MoS<SUB>2</SUB>-CT photocatalysts have been successfully synthesized by two-step method. </LI> <LI> The porous structure can enhance photogenerated electron-hole pairs separation. </LI> <LI> The 3% MoS<SUB>2</SUB>-CT shows an excellent H<SUB>2</SUB> evolution rate of 4146 μmol h<SUP>−1</SUP> g<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Nanostructured Lithium Nickel Manganese Oxides for Lithium-Ion Batteries

Deng, Haixia,Belharouak, Ilias,Cook, Russel E.,Wu, Huiming,Sun, Yang-Kook,Amine, Khalil The Electrochemical Society 2010 Journal of the Electrochemical Society Vol.157 No.4

RNAi‐mediated knockdown of juvenile hormone esterase causes mortality and malformation in Tribolium castaneum

Xu Zhanyi,Yan Ru,Qian Jiali,Chen Dongping,Guo Yirong,Zhu Guonian,Wu Huiming,Chen Mengli 한국곤충학회 2022 Entomological Research Vol.52 No.11

RNA interference is an efficient approach for gene function identification and a potential novel strategy for selectively controlling pests. The red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), is a major global storage pest, which causes great economic loss. Juvenile hormone esterase (JHE), a carboxylesterase, is responsible for the degradation of juvenile hormone. However, the knockdown effect of jhe on metamorphosis of pupae or adult in T. castaneum is unknown. In this study, we analyzed the expression profiles of Tc j h e in the larval stage, we found that Tc j h e was expressed throughout the whole larval instars and the expression levels were relatively high right after molting. Furthermore, we knocked down the expression of Tcjhe by injecting dsTc j h e , which significantly increased the mortality of adults and decreased the eclosion rate. In addition, abnormal developmental phenotypes, including wing deformitity, pupal–adult monsters and shrunken adults, were observed. Our finding indicates that JHE plays an important role in the metamorphosis and development in T. castaneum, suggesting that Tc j h e could be used as a potential target for the development of RNAi-based control strategies in T. castaneum.

Synthesis of full concentration gradient cathode studied by high energy X-ray diffraction

Li, Yan,Xu, Rui,Ren, Yang,Lu, Jun,Wu, Huiming,Wang, Lifen,Miller, Dean J.,Sun, Yang-Kook,Amine, Khalil,Chen, Zonghai Elsevier 2016 Nano energy Vol.19 No.-

<P><B>Abstract</B></P> <P>Nickel-rich metal oxides have been widely pursued as promising cathode materials for high energy-density lithium-ion batteries. Nickel-rich lithium transition metal oxides can deliver a high specific capacity during cycling, but can react with non-aqueous electrolytes. In this work, we have employed a full concentration gradient (FCG) design to provide a nickel-rich core to deliver high capacity and a manganese-rich outer layer to provide enhanced stability and cycle life. <I>In situ</I> high-energy X-ray diffraction was utilized to study the structural evolution of oxides during the solid-state synthesis of FCG lithium transition metal oxide with a nominal composition of LiNi<SUB>0.6</SUB>Mn<SUB>0.2</SUB>Co<SUB>0.2</SUB>O<SUB>2</SUB>. We found that both the pre-heating step and the sintering temperature were critical in controlling phase separation of the transition metal oxides and minimizing the content of Li<SUB>2</SUB>CO<SUB>3</SUB> and NiO, both of which deteriorate the electrochemical performance of the final material. The insights revealed in this work can also be utilized for the design of other nickel-rich high energy-density cathode materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Solid-state synthesis of FCG cathode is investigated by <I>in situ</I> XRD. </LI> <LI> Covariance analysis and Rietveld refinement are used to analyze the HEXRD data. </LI> <LI> Synthetic optimization of FCG cathode with excellent electrochemical performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Benefit from the covariance analysis and Rietveld refinement of <I>in situ</I> HEXRD data during the solid state synthesis, we can optimized the solid state synthesis conditions in a short time. And the full concentration gradient cathode composites (nickel-rich core and manganese-rich outer layer) with excellent electrochemical performance are obtained.</P> <P>[DISPLAY OMISSION]</P>

A novel concentration-gradient Li[Ni_0.83Co_0.07Mn_0.10]O₂ cathode material for high-energy lithium-ion batteries

Sun, Yang-Kook,Lee, Bo-Ram,Noh, Hyung-Ju,Wu, Huiming,Myung, Seung-Taek,Amine, Khalil Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.27

<P>A novel concentration-gradient Li[Ni<SUB>0.83</SUB>Co<SUB>0.07</SUB>Mn<SUB>0.10</SUB>]O<SUB>2</SUB> cathode material was successfully synthesized <I>via</I> co-precipitation, in which the core Li[Ni<SUB>0.9</SUB>Co<SUB>0.05</SUB>Mn<SUB>0.05</SUB>]O<SUB>2</SUB> was encapsulated completely with a stable concentration-gradient layer having reduced Ni content. The electrochemical and thermal properties of the concentration-gradient Li[Ni<SUB>0.83</SUB>Co<SUB>0.07</SUB>Mn<SUB>0.10</SUB>]O<SUB>2</SUB> were studied and compared to those of the core Li[Ni<SUB>0.9</SUB>Co<SUB>0.05</SUB>Mn<SUB>0.05</SUB>]O<SUB>2</SUB> material alone. The concentration-gradient material had a superior lithium intercalation stability and thermal stability compared to the core material. The high capacity was delivered from the Ni-rich core Li[Ni<SUB>0.9</SUB>Co<SUB>0.05</SUB>Mn<SUB>0.05</SUB>]O<SUB>2</SUB>, and the improved thermal stability was achieved by the Ni-depleted concentration-gradient layer with outer surface composition of Li[Ni<SUB>0.68</SUB>Co<SUB>0.12</SUB>Mn<SUB>0.20</SUB>]O<SUB>2</SUB>. The concentration-gradient materials open a new era for the development of advanced Li-ion batteries with high energy density, long cycle life, and improved safety.</P> <P>Graphic Abstract</P><P>A novel concentration-gradient Li[Ni<SUB>0.83</SUB>Co<SUB>0.07</SUB>Mn<SUB>0.10</SUB>]O<SUB>2</SUB> cathode material showed a very high reversible capacity of 213 m Ah g<SUP>−1</SUP> as well as superior lithium intercalation stability and thermal stability compared to the core Li[Ni<SUB>0.9</SUB>Co<SUB>0.05</SUB>Mn<SUB>0.05</SUB>]O<SUB>2</SUB> material. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm04242k'> </P>