Spontaneous Sm³⁺→Sm²⁺ reduction ability of MAl₂Si₂O₈ (M = Sr, Ba): Sm

Li, Ling,Wang, Wenjun,Pan, Yu,Liu, Xiaoguang,Noh, Hyeon Mi,Jeong, Jung Hyun ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.723 No.-

<P><B>Abstract</B></P> <P>In air atmosphere, the spontaneous reduction abilities of Sm<SUP>3+</SUP>→Sm<SUP>2+</SUP> in Sm ions doped monoclinic SrAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (SASO) and BaAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (M-BASO) as well as hexagonal BaAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (H-BASO) are investigated. Sm ions doped MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (M = Sr, Ba) samples were synthesized using Pechini-type sol-gel technology and sintered in air atmosphere and reducing condition, respectively. By comparing the photoluminescence properties of Sm doped MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (M = Sr, Ba) calcined in air with that in reducing condition, the spontaneous reduction of Sm<SUP>3+</SUP>→Sm<SUP>2+</SUP> can be detected only in the host lattice H-BASO. The essential that makes the reduction of Sm<SUP>3+</SUP> to Sm<SUP>2+</SUP> was investigated by calculating their chemical bonds parameter quantitatively. The important key environmental factor of Ba<SUP>2+</SUP> in H-BASO is the largest among the three samples MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB>. It indicates that the hexagonal H-BASO sample is the easiest one to realize the spontaneous reduction of Sm<SUP>3+</SUP>→Sm<SUP>2+</SUP> among Sm doped MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB> (M = Sr, Ba) samples. The needed energy transferring one electron of the ligand to the central ions Sm<SUP>3+</SUP> in H-BASO:Sm is the lowest. The theoretical analysis agrees well with the experimental result. Our work provides with the theoretical and experimental foundation for the spontaneous reduction of trivalent samarium in the crystals.</P> <P><B>Highlights</B></P> <P> <UL> <LI> In air atmosphere, the PL properties of Sm<SUP>3+</SUP> in MAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB>:Sm are investigated. </LI> <LI> The abnormal Sm<SUP>3+</SUP>→Sm<SUP>2+</SUP> reduction can be detected only in the hexagonal BaAl<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>8</SUB>. </LI> <LI> The reduction essential was determined by calculating the chemical bond parameters. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Well-designed Te/SnS₂/Ag artificial nanoleaves for enabling and enhancing visible-light driven overall splitting of pure water

Yan, Changzeng,Xue, Xiaolan,Zhang, Wenjun,Li, Xiaojie,Liu, Juan,Yang, Songyuan,Hu, Yi,Chen, Renpeng,Yan, Yaping,Zhu, Guoyin,Kang, Zhenhui,Kang, Dae Joon,Liu, Jie,Jin, Zhong unknown 2017 Nano energy Vol.39 No.-

<P><B>Abstract</B></P> <P>To produce hydrogen and oxygen from photocatalytic overall splitting of pure water provides a promising green route to directly convert solar energy to clean fuel. However, the design and fabrication of high-efficiency photocatalyst is challenging. Here we present that by connecting different nanostructures together in a rational fashion, components that cannot individually split water into H<SUB>2</SUB> and O<SUB>2</SUB> can work together as efficient photocatalyst with high solar-to-hydrogen (STH) energy conversion efficiency and avoid the use of any sacrificial reagent. Specifically, Te/SnS<SUB>2</SUB>/Ag artificial nanoleaves (ANLs) consist of ultrathin SnS<SUB>2</SUB> nanoplates grown on Te nanowires and decorated with numerous Ag nanoparticles. The appropriate band structure of Te/SnS<SUB>2</SUB> p-n junctions and the surface plasmon resonance of Ag nanoparticles synergistically enhance the quantum yield and separation efficiency of electron-hole pairs. As a result, Te/SnS<SUB>2</SUB>/Ag ANLs enable visible-light driven overall water-splitting without any sacrificial reagent and exhibit high H<SUB>2</SUB> and O<SUB>2</SUB> production rates of 332.4 and 166.2μmolh<SUP>−1</SUP>, respectively. Well-preserved structure after long-term measurement indicates its high stability. It represents a feasible approach for direct H<SUB>2</SUB> production from only sunlight, pure water, and rationally-designed ANL photocatalysts.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Te/SnS<SUB>2</SUB>/Ag ANLs heterostructure is prepared to catalyze overall water splitting. </LI> <LI> The catalyst show impressive H<SUB>2</SUB> and O<SUB>2</SUB> production rate under visible light. </LI> <LI> The structure and efficiency of catalyst shows no degradation after 10 days. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A Sensing System of the Halbach Array Permanent Magnet Spherical Motor Based on 3-D Hall Sensor

Li, Hongfeng,Liu, Wenjun,Li, Bin The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.1

This paper proposes a sensing system of the Halbach array permanent magnet spherical motor(PMSM). The rotor position can be obtained by solving three rotation angles, which revolves around 3 reference axes of the stator. With the development of 3-D hall sensor, the position identification problem of the Halbach array PMSM based on rotor magnetic field is studied in this paper. A nonlinear and serious coupling relationship between the rotation angles and the measured magnetic flux density is established on the basis of the rotation transformation theory and the magnetic field model. In order to get rid of the influence on position detection caused by the harmonics of rotor magnetic field and the stator coil magnetic field, a sensor location combination scheme is proposed. In order to solve the nonlinear equation fast and accurately, a new position solution algorithm which combines the merits of gradient projection and particle swarm optimization(PSO) is presented. Then the rotation angles are obtained and the rotor position is identified. The validity of the sensing system is verified through the simulation.

One-Step Hydrothermal Deposition of Ag-Doped g-C3N4-TiO2 Nanocomposites on Cotton Fabric Surface with Enhanced Photocatalytic Activity

Wenjun Li,Hui Zhang,Pei Chen,Jiale Yao,Xiangzhi Dong 한국섬유공학회 2023 Fibers and polymers Vol.24 No.2

In this study, Ag-doped g-C3N4-TiO2 nanocomposite photocatalysts were deposited on the surface of cotton fabric by a simpleone-step hydrothermal method. The structure features of as-modified cotton fabric were examined by a series of characterizationtechniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction(XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (DRS) andphotoluminescence spectroscopy (PL). The experimental results showed that highly dispersed Ag nanoparticles were dopedinto g-C3N4-TiO2 nanocomposites which were evenly coated on the fabric surface. The introduction of Ag nanoparticles intog-C3N4-TiO2 composites could significantly improve the photodegradation rate of methyl orange (MO) dye under visiblelight irradiation. Importantly, the doping site of Ag nanoparticles had a significant influence on the photocatalytic activityof Ag-doped g-C3N4-TiO2 nanocomposites. Compared with the g-C3N4-TiO2 coated cotton fabric, the Ag-doped g-C3N4-TiO2 coated cotton fabric displayed excellent photocatalytic properties for the photodegradation of MO dyes because of thenarrowed band gap and the faster separation and transfer of photoinduced charge carriers. The substrate of cotton fabric hadlittle influence on the active radicals produced by the Ag-doped g-C3N4-TiO2 nanocomposites. In addition, the as-modifiedcotton fabric exhibited good reusability and stability after five recycles for the photodegradation of MO dyes.

A Sensing System of the Halbach Array Permanent Magnet Spherical Motor Based on 3-D Hall Sensor

Hongfeng Li,Wenjun Liu,Bin Li 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.1

This paper proposes a sensing system of the Halbach array permanent magnet spherical motor(PMSM). The rotor position can be obtained by solving three rotation angles, which revolves around 3 reference axes of the stator. With the development of 3-D hall sensor, the position identification problem of the Halbach array PMSM based on rotor magnetic field is studied in this paper. A nonlinear and serious coupling relationship between the rotation angles and the measured magnetic flux density is established on the basis of the rotation transformation theory and the magnetic field model. In order to get rid of the influence on position detection caused by the harmonics of rotor magnetic field and the stator coil magnetic field, a sensor location combination scheme is proposed. In order to solve the nonlinear equation fast and accurately, a new position solution algorithm which combines the merits of gradient projection and particle swarm optimization(PSO) is presented. Then the rotation angles are obtained and the rotor position is identified. The validity of the sensing system is verified through the simulation.

Eu³⁺→Eu²⁺ unusual reduction and bond energy in MAlSi₂O₆:Eu (M = Li, Na, K, Rb, Cs)

Pan, Yu,Wang, Wenjun,Zhu, Yuhan,Xu, Haibing,Noh, Hyeon Mi,Jeong, Jung Hyun,Liu, Xiaoguang,Li, Ling Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.7

<P><B>Abstract</B></P> <P>Eu-doped MAlSi<SUB>2</SUB>O<SUB>6</SUB> (M = Li, Na, K, Rb, Cs) phosphors were synthesized by solid-state reaction in air. The crystal structure and optical properties of the phosphors were investigated by X-ray powder diffraction and photoluminescence. Their emission spectra are composed of some broad bands coming from the 5d-4f transition of Eu<SUP>2+</SUP> and some sharp emission peaks coming from the f-f transitions of Eu<SUP>3+</SUP>. The co-existence of Eu<SUP>3+</SUP> and Eu<SUP>2+</SUP> cations is detected in MAlSi<SUB>2</SUB>O<SUB>6</SUB>:2%Eu, which shows that the unusual Eu<SUP>3+</SUP>→Eu<SUP>2+</SUP> reduction process occurs in MAlSi<SUB>2</SUB>O<SUB>6</SUB>. The preferential occupancy of Eu<SUP>3+</SUP> or Eu<SUP>2+</SUP> in MAlSi<SUB>2</SUB>O<SUB>6</SUB> can be calculated to be M<SUP>+</SUP> sites by the bond-energy method. The deviation of the Eu<SUP>3+</SUP>–O<SUP>2-</SUP> bond energy is closed to that of the Eu<SUP>2+</SUP>–O<SUP>2-</SUP> bond energy, which means that Eu<SUP>3+</SUP> and Eu<SUP>2+</SUP> can coexist in air. The abnormal reduction of Eu<SUP>3+</SUP> to Eu<SUP>2+</SUP> can be explained by charge compensation model. The doped Eu<SUP>3+</SUP> was induced to M<SUP>+</SUP> and the vacancy (<I>V</I> <SUB> <I>M</I> </SUB>) may be formed. The vacancy(<I>V</I> <SUB> <I>M</I> </SUB>) acted as a donor of electrons, and the Eu M ∙ ∙ defect acted as an acceptor of electrons. The theoretical result is consistent with the experimental phenomenon.</P>

Effects of resveratrol on the inflammatory response and renal injury in hyperuricemic rats

Xiao Benxi,Ma Wenjun,Zheng Ying,Li Zhen,Li Dan,Zhang Yanjun,Li Yuanhong,Wang Duan 한국영양학회 2021 Nutrition Research and Practice Vol.15 No.1

BACKGROUND/OBJECTIVES: Hyperuricemic nephropathy is a common cause of acute kidney injury. Resveratrol can ameliorate kidney injury, but the explicit mechanism remains unclear. We investigated the effects of resveratrol on the inflammatory response and renal injury in hyperuricemic rats. MATERIALS/METHODS: A rat model of hyperuricemic nephropathy was established by the oral administration of a mixture of adenine and potassium oxinate. Biochemical analysis and hematoxylin and eosin staining were performed to assess the rat kidney function. Enzyme-linked immunosorbent assays were performed to evaluate the immune and oxidative responses. RESULTS: The expression levels of urine albumin and β2-microglobulin were significantly decreased after resveratrol treatment. In addition, the levels of serum creatinine and uric acid were significantly decreased in the resveratrol groups, compared with the control group. The levels of proinflammatory factors, such as interleukin-1β and tumor necrosis factor-α, in kidney tissue and serum were also increased in the hyperuricemic rats, and resveratrol treatment inhibited their expression. Moreover, the total antioxidant capacity in kidney tissue as well as the superoxide dismutase and xanthine oxidase levels in serum were all decreased by resveratrol treatment. CONCLUSIONS: Resveratrol may protect against hyperuricemic nephropathy through regulating the inflammatory response.

Small-World Features of Real-World Networks

Wenjun Xiao,Meisheng Li,Guanrong Chen 한국통신학회 2017 Journal of communications and networks Vol.19 No.3

It is well known that there are a large number of complex networks that have vertex-degree distributionsin a power-law form of $ck^{-\gamma}$, where $\emph{k}$ is the degree variable and $\emph{c}$ and $\gamma$are scaling and exponent constants. Recently, we found that it is effective to reveal the underlyingmechanism of power-law formation in real-world networks by analyzing their vertex-degree sequences. We showed before that, for a scale-free network of size \emph{N}, if its vertex-degree sequence is$ k_{1}<k_{2}<{\cdots}<k_{l} $, where $\{k_{1},k_{2},{{\cdots}},k_{l}\}$ is the set of all non-equal vertex degreesin the network, and if its power exponent satisfies $\gamma>1$, then the length \emph{l} of the abovevertex-degree sequence is of order $\log N$. We underline that this conclusion is important, which proves thatthe length of the vertex-degree sequence is a fundamental characteristic of a scale-free network. In this paper,we further investigate complex networks with more general distributions and we prove that the same conclusionabout the vertex-degree sequences holds even for non-network type of complex systems. We thereby conclude thatreal-world networks typically possess small-world features. We support this conclusion by verifying a largenumber of real-world networks and systems. To that end, we discuss some potential applications of the new findingin various fields of science, engineering and society, demonstrating that the conclusion is important with manyreal applications.

Intercalation of Europium Inclusion Complex of β-Cyclodextrin into Layered Double Hydroxides Through Layer-By-Layer Assembly and Its Luminescent Properties

Wenjun Zhang,Yi Chen,Yanlin Li,Sumin Guan,Yan Chen,Qian-Qian Yang,Lu Liu,Qing-Chen Xue,Yu-Cui Guang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.10

"In this work, organic–inorganic hybrid ultrathin transparent films (UTFs), produced by layer-by-layer (LBL) assembly of the europium inclusion complex of β-cyclodextrin ( β-CD) and Mg–Al layered double hydroxide (MgAl–NO3–LDHs) nanosheets, are reported. UV-visible (UV-Vis) absorption and fluorescence spectroscopy show orderly growth of the europium inclusion complex of β-CD/layered double hydroxide (EICC/LDH) films with an increasing number of deposition cycles. X-ray diffraction and scanning electron microscopy measurements indicate that the films feature periodic layered structures with uniform surface morphology. Moreover, when EICC is assembled with inorganic rigid LDH nanosheets, the lifetimes are prolonged due to the isolation effect, and the UTFs are transparent with high brightness, which indicate that these films could serve as new optical materials."

Polymorphism of Insulin-like Growth Factor I Gene in Six Chicken Breeds and Its Relationship with Growth Traits

Wang, Wenjun,Ouyang, Kehui,Ouyang, Jianhua,Li, Haihua,Lin, Shumao,Sun, Han Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.3

The polymorphism of insulin-like growth factor I (IGF I) in 6 chicken breeds (total n=515) was detected by PCR-Pst IRFLP, and allele A (621 bp) or allele B (364 and 257 bp) were observed. In these chicken breeds, it was found that exotic chicken carried high frequencies of allele B, while Chinese native chicken breeds carried high frequencies of allele A. Meanwhile the role of IGF I was investigated in 133 Ningdu Yellow chicken and 162 Wanzhai Yellow chicken. Five growth traits were recorded for analyzing the association between IGFI gene polymorphism and performance. In both the Ningdu and Wanzhai Yellow breeds, body weight at 4 months was significantly higher with BB genotype than with AA genotype (p<0.05). Furthermore, body weight at 2 months in the Wanzhai Yellow breeds was also higher with BB genotype than with AA genotype (p<0.05). There were no differences among the genotypes for the other traits studied. Based on these results, it is necessary to do more studies on IGFI before making the IGFI locus into the application of maker-assisted selection programms.