Probing the origin of the enhanced catalytic performance of sp³@sp² nanocarbon supported Pd catalyst for CO oxidation

Zhang, Liyun,Ding, Yuxiao,Koh, Yoobin Esther,Mun, Bongjin Simon,Wu, Kuang-Hsu,Niu, Yiming,Shi, Wen,Zhang, Bingsen Elsevier 2020 Carbon Vol.156 No.-

<P><B>Abstract</B></P> <P>Tuning the fine structure of carbon support is crucial for modifying the metal-support interface (MSI) in order to harvest a high-performance catalysis. Herein, a core–shell sp<SUP>3</SUP>@sp<SUP>2</SUP> nanocarbon (nanodiamond@graphene, ND@G) and a pure sp<SUP>2</SUP> carbon derivative (onion-like carbon, OLC) were applied to support Pd nanoparticles. We found that Pd/ND@G displayed a superior catalytic activity for CO oxidation reaction with a TOF of 2.9 times higher than that of Pd/OLC at 46 °C. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and ambient pressure X-ray photoelectron spectroscopy (AP-XPS) revealed that, different with the Pd/OLC system, a unique interface microstructure was formed in Pd/ND@G, which not only provides a high exposure of active sites, but also enhances the Pd surface reactivity toward oxygen species, thus leading to a superior catalytic activity of Pd/ND@G. Moreover, the temperature-programmed surface reaction (TPSR) results showed that CO oxidation on Pd/ND@G undergoes an unusual termolecular Eley–Rideal (TER) mechanism, which has a lower energy barrier as compared to the traditional Langmuir-Hinshelwood (LH) and ER mechanism.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

College education and attitudes toward democracy in China: an empirical study

Gang Wang,Liyun Wu,Rongbin Han 서울대학교 교육연구소 2015 Asia Pacific Education Review Vol.16 No.3

The modernization theory contends that there is a link between education and democracy. Yet few empirical studies have been done to investigate the role of higher education on promoting democratic values in the Chinese context. Using China General Social Survey 2006, this paper generates several findings which are not completely consistent with the existing theoretical explanations on political development. Specifically, the college-educated Chinese citizens not only agree that there is need to improve democracy, but support various types of political participation and resist the government-oriented petitioning. However, though entrepreneurial elites (private business owners) and political elites (Chinese communist party members) demonstrate preference to democracy in principle, empirical evidence suggests that they are much less likely to support political participation that challenges the authoritarian regime in China compared to knowledgebased elites (college-educated adults).

Effects of echinomycin on endothelin-2 expression and ovulation in immature rats primed with gonadotropins

Zhengchao Wang,Yanqing Wu,Liyun Chen,Qianping Luo,Jisen Zhang,Jiajie Chen,Zimiao Luo,Xiaohong Huang,Yong Cheng,Zhenghong Zhang 생화학분자생물학회 2012 Experimental and molecular medicine Vol.44 No.10

Echinomycin is a small-molecule inhibitor of hypoxia- inducible factor-1 DNA-binding activity, which plays a crucial role in ovarian ovulation in mammalians. The present study was designed to test the hypothesis that hypoxia-inducible factor (HIF)-1α-mediated endothelin (ET)-2 expressions contributed to ovarian ovulation in response to human chorionic gonadotropin (hCG) during gonadotropin-induced superuvulation. By real-time RT-PCR analysis, ET-2 mRNA level was found to significantly decrease in the ovaries after chinomycin treatment, while HIF-1α mRNA and protein expression was not obviously changed. Further analysis also showed that these changes of ET-2 mRNA were consistent with HIF-1 activity in the ovaires, which is similar with HIF-1α and ET-2 expression in the granulosa cells with gonadotropin and echinomycin treatments. The results of HIF-1α and ET-2 expression in the granulosa cells transfected with cis-element oligodeoxynucleotide (dsODN) under gonadotropin treatment further indicated HIF-1α directly mediated the transcriptional activation of ET-2 during gonadotropin- induced superuvulation. Taken together, these results demonstrated that HIF-1α-mediated ET-2 transcriptional activation is one of the important mechanisms regulating gonadotropin-induced mammalian ovulatory precess in vivo. Echinomycin is a small-molecule inhibitor of hypoxia- inducible factor-1 DNA-binding activity, which plays a crucial role in ovarian ovulation in mammalians. The present study was designed to test the hypothesis that hypoxia-inducible factor (HIF)-1α-mediated endothelin (ET)-2 expressions contributed to ovarian ovulation in response to human chorionic gonadotropin (hCG) during gonadotropin-induced superuvulation. By real-time RT-PCR analysis, ET-2 mRNA level was found to significantly decrease in the ovaries after chinomycin treatment, while HIF-1α mRNA and protein expression was not obviously changed. Further analysis also showed that these changes of ET-2 mRNA were consistent with HIF-1 activity in the ovaires, which is similar with HIF-1α and ET-2 expression in the granulosa cells with gonadotropin and echinomycin treatments. The results of HIF-1α and ET-2 expression in the granulosa cells transfected with cis-element oligodeoxynucleotide (dsODN) under gonadotropin treatment further indicated HIF-1α directly mediated the transcriptional activation of ET-2 during gonadotropin- induced superuvulation. Taken together, these results demonstrated that HIF-1α-mediated ET-2 transcriptional activation is one of the important mechanisms regulating gonadotropin-induced mammalian ovulatory precess in vivo.

Hydrothermal Synthesis and Electrochemical Property of Self-Assembly K10 [H2W12O42] · 10H2O Nanorod

Xingang Kong,Wen Li,Liyun Cao,Jianfeng Huang,Jianpeng Wu,Jie Fei,Jiayin Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.6

Using KOH and WO3 as raw materials, K10[H2W12O42] · 10H2O nanorod was successfully synthesized via controlling the pH value and the K/W mole ratio of hydrothermal system. The structure and morphology of the samples were characterized by XRD, SEM, TEM, HRTEM and selected area electron diffraction (SAED). The size of K10[H2W12O42] · 10H2O nanorod was about 300 nm in width and 3–10 µm in length. The nanorod consisted of self-assembly nanowires with about 10 nm in width. Moreover, the electrochemical performance of K10[H2W12O42] · 10H2O as anode material was investigated, indicating that the as-prepared sample electrode possessed a certain ability of lithium ion insertion/extraction, and exhibited a high initial discharge capacity of 310 mAh g-1.

Effect of TiBCN Content on Microstructure and Properties of Laser Cladding Ti/TiBCN Composite Coatings

Yuxin Li,Keqiang Su,Peikang Bai,Liyun Wu,Bin Liu,Hongwen Su,Wenbo Du 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

The Ti/TiBCN composite coatings were fabricated on the substrate of Ti6Al4V alloy by laser cladding. The effects of TiBCNcontent on the microstructre, microhardness, corrosion resistance and tribological properties of the composite coatings werestudied. The results showed that, when the TiBCN content was 60 wt%, the composite coatings were mainly composed ofthe dendritic and rod-shaped TiBCN phases, small white lump TiC phases, fine lamellar TiN phases, small and scatteredwhite block TiB2phases, In addition, there was a small quantity of short whisker Al3Tiphases and uniform layer blockTiAl phases. Furhtermore, the maximum microhardness was 1596 HV, which was about 4.6 folds greater than that of thesubstrate; the corrosion potential (Ecorr) reached − 1.258 V and the corrosion current density (Icorr) was 4.035 × 10−5 A/cm2,which was one order lower than that of the substrate (1.172 × 10−4 A/cm2); the worn surface was relatively smooth and themass loss (1.22 g) was only 9/50 of that of the substrate (6.71 g).

A Novel Facile and Green Synthesis Protocol to Prepare High Strength Regenerated Silk Fibroin/SiO2 Composite Fiber

Qiang Liu,Zhaohui Meng,Ronghui Wu,Liyun Ma,Wu Qiu,Honghao Zhang,Shuihong Zhu,Lingqing Kong,Zijjie Xu,Aniruddha Patil,Xiangyang Liu 한국섬유공학회 2019 Fibers and polymers Vol.20 No.10

In this work, regenerated silk fibroin (RSF) and silicon dioxide (SiO2) composite fiber was successfully extrudedby wet spinning method. The effect of SiO2 addition on structure of the composite fiber at microscopic level is studied, whichsubsequently correlated to the mechanical performance. The best concentration ratio for composite fiber is identified byscreening SiO2 concentration from 0.025 w/w% to 0.5 w/w%. The experimental results revealed that the SiO2 at a lowconcentration of 0.1 w/w% was well distributed. The breaking stress, breaking strain and Young’s modulus at 0.1 w/w% SiO2addition of the RSF fibers increased considerably compared to the neat RSF fibers from 243±3 to 458±21 MPa, 51±4 % to54±7 % and 6.34±0.55 to 11.69±1.12 GPa, respectively. To the best of our knowledge, this is the first report for RSF/SiO2composite fiber. We believed the insight provided in this report which looks into the structural evolution should be beneficialto the future design and building of other advanced functional fibers.