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R&D Status of High-current Accelerators at IFP
J. J. Deng,J. S. Shi,W. P. Xie,L. W. Zhang,K. Z. Zhang,S. P. Feng,J. Li,M. Wang,Y. He,L. S. Xia,Z. Y. Dai,H. T. Li,L. Wen,S. F. Chen,X. Li,Q. G. Lai,M. H. Xia,Y. C. Guan,S. Y. Song,L. Chen 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61
High-current accelerators have many important applications in Z-pinches, high-power microwaves, and free electron lasers, imploding liners and radiography and so on. Research activities on Zpinches, imploding liners, radiography at the Institute of Fluid Physics (IFP) are introduced. Several main high-current accelerators developed and being developed at IFP are described, such as the Linear Induction Accelerator X-Ray Facility Upgrade (LIAXFU, 12 MeV, 2.5 kA, 90 ns), the Dragon-I linear induction accelerator (20 MeV, 2.5 kA, 60 ns), and the Primary Test Stand for Z-pinch (PTS, 10 MA, 120 ns). The design of Dragon-II linear induction accelerator (20 MeV, 2.5 kA, 3 × 60 ns) to be built will be presented briefly.
Solar Water Splitting with a Hydrogenase Integrated in Photoelectrochemical Tandem Cells
Nam, Dong Heon,Zhang, Jenny Z.,Andrei, Virgil,Kornienko, Nikolay,Heidary, Nina,Wagner, Andreas,Nakanishi, Kenichi,Sokol, Katarzyna P.,Slater, Barnaby,Zebger, Ingo,Hofmann, Stephan,Fontecilla‐,Ca John Wiley and Sons Inc. 2018 Angewandte Chemie Vol.57 No.33
<P><B>Abstract</B></P><P>Hydrogenases (H<SUB>2</SUB>ases) are benchmark electrocatalysts for H<SUB>2</SUB> production, both in biology and (photo)catalysis in vitro. We report the tailoring of a p‐type Si photocathode for optimal loading and wiring of H<SUB>2</SUB>ase through the introduction of a hierarchical inverse opal (IO) TiO<SUB>2</SUB> interlayer. This proton‐reducing Si|IO‐TiO<SUB>2</SUB>|H<SUB>2</SUB>ase photocathode is capable of driving overall water splitting in combination with a photoanode. We demonstrate unassisted (bias‐free) water splitting by wiring Si|IO‐TiO<SUB>2</SUB>|H<SUB>2</SUB>ase to a modified BiVO<SUB>4</SUB> photoanode in a photoelectrochemical (PEC) cell during several hours of irradiation. Connecting the Si|IO‐TiO<SUB>2</SUB>|H<SUB>2</SUB>ase to a photosystem II (PSII) photoanode provides proof of concept for an engineered Z‐scheme that replaces the non‐complementary, natural light absorber photosystem I with a complementary abiotic silicon photocathode.</P>
Zhang, Z.H.,Fan, X.J.,Guo, H.X.,Zhang, W.,Zhang, C.Y.,Luo, F.Y. The Korean Vacuum Society 1998 Applied Science and Convergence Technology Vol.7 No.1
Amorphous ternary $Si_xC_yN-z$ thin films were obtained by plasma enhanced chemical vapor deposition(PECVD) using $N_2, SiH_4 \;and \;C_2H_4$ as the reaction sources. The chemical state were characterized by x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy(FTIR). The optical properties of the thin films were investigated by UV-visible spectrophotometer and ellipsometer, and the optical band gaps of thin films were determined from corresponding transmittance spectra following Tauc equation.
Zhang, Z.,Choi, M.,Baek, M.,Hwang, I.,Cho, C.,Deng, Z.,Lee, J.,Yong, K. Springer Science + Business Media 2017 NANO RESEARCH Vol.10 No.7
<P>Fast charge transfer and anti-photocorrosion are two crucial factors for developing efficient, durable photoanodes for photoelectrochemical (PEC) cells. Reduced graphene oxide (RGO) is a promising photoanode element that can provide both of these. In this study, we elucidated the roles of RGO in the charge transfer and surface passivation of photoanodes by the precise design of a RGO-wrapped photoanode and examination of its PEC properties. Arrays of hetero-nanorods (HNRs) with three different designs were fabricated as photoanodes using RGO, CdSe nanoparticles (NPs), and ZnO nanorods (NRs) as building blocks. CdSe@ZnO HNRs were prepared by decorating ZnO NRs with CdSe NPs. Finite-element analysis and experimental studies demonstrated that in the CdSe@ZnO HNRs, if only the ZnO NRs were wrapped by RGO, the conductivity between CdSe and ZnO was enhanced by RGO to shuttle charges. If RGO only surrounded the outside of the CdSe@ZnO HNRs, the corrosion was slowed owing to the passivation effect of RGO, which increased the electron lifetime of the photoanode. If both CdSe and ZnO were fully wrapped by RGO, the advantages of the two aforementioned cases were both obtained. RGO-wrapped CdSe@ZnO HNRs with position-controlled designs are promising photoanode materials with a high PEC efficiency, and the developed synthesis process can be applied to explore the design and fabrication of next-generation photoanodes using RGO as a building block.</P>
Adaptive control for a class of nonlinear time-delay systems with dead-zone input
Zhang, Z.,Park, J.H.,Zhang, K.,Lu, J. Pergamon Press [etc.] 2016 Journal of the Franklin Institute Vol.353 No.17
<P>In this paper, we consider the same class of systems as in a previous paper, i.e. a class of uncertain nonlinear systems with state time-varying delays and nonsymmetric dead-zone input. The dead-zone parameters are unknown, and the delay-related nonlinearity is bounded by the partially known nonlinear functions. No knowledge is assumed on the slope sign of the dead-zone nonlinearity and the upper bounds of the time delays and their derivatives. By employing the Nussbaum gain approach and choosing a proper Lyapunov Krasovskii functional, an adaptive compensation control algorithm is developed. The explicit expression of the control gain function is constructed. The boundedness of all the closed-loop signals is established, and the desired tracking performance is guaranteed by choosing the appropriate design parameters. The effectiveness of the proposed control algorithm is demonstrated by two simulation examples. (C) 2016 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.</P>
Application of a sorbent trap system to gas-phase elemental and oxidized mercury analysis
Zhang, Z.,Eom, Y.,Lee, M.J.,Lee, T.G. Pergamon Press 2016 CHEMOSPHERE - Vol.154 No.-
A sorbent trap that utilizes activated carbon (AC) as the solid trapping medium is a new technology for measuring total mercury (Hg) emissions from combustion facilities. In this study, sorbent trap technology was further developed, improved and evaluated at the laboratory scale. AC was impregnated with 5% aqua regia to enhance its Hg adsorption capacity. Sorbent traps spiked with an Hg standard solution were found to be reproducibly prepared and highly stable. The effect of the Hg concentration on the spiking efficiency was further investigated. The adsorption of elemental and oxidized Hg by the sorbent trap was studied under various experimental conditions (temperature, flow rate and inlet Hg concentration). The Hg concentration of the flue gas effluent from the sorbent trap was measured. In addition, the concentration of Hg adsorbed on the AC was determined by digesting the used AC with an acid according to US EPA method 3052 and then analyzing it with cold vapor atomic absorption spectrometry. Furthermore, the gas-phase Hg emissions from a combustion source were measured using the sorbent trap according to US EPA method 30B. The results showed that the sorbent trap could be used for Hg concentrations between 10.0 and 40.0 μg m<SUP>-3</SUP> and flow rates between 0.5 and 1.0 lpm with adsorption efficiencies greater than 90%.
Zhang, X.,Shi, L.,Li, X.,Sheng, Q.,Yao, L.,Shen, D.,Lu, Z.R.,Zhou, H.M.,Park, Y.D.,Lee, J.,Zhang, Q. Society for Bioscience and Bioengineering, Japan ; 2014 Journal of bioscience and bioengineering Vol.117 No.6
Understanding the mechanism of inhibition of α-glucosidase (EC 3.2.1.20) is clinically important because of the involvement of this enzyme in type 2 diabetes mellitus. In this study, we conducted inhibition kinetics of α-glucosidase with Ca<SUP>2+</SUP> and 10-ns molecular dynamics simulations. We found that direct binding of Ca<SUP>2+</SUP> to the enzyme induced structural changes and inhibited enzyme activity. Ca<SUP>2+</SUP> inhibited α-glucosidase in a mixed-type reaction (K<SUB>i</SUB> = 27.0 +/- 2.0 mM) and directly induced the unfolding of α-glucosidase, which resulted in the exposure of hydrophobic residues. The simulations suggest that thirteen Ca<SUP>2+</SUP> ions may interact with α-glucosidase residues and that the Ca<SUP>2+</SUP> binding sites are associated with the structural changes in α-glucosidase. Our study provides insight into the mechanism of the Ca<SUP>2+</SUP>-induced structural changes in α-glucosidase and the inhibition of ligand binding. These results suggest that Ca<SUP>2+</SUP> could act as a potent inhibitor of α-glucosidase for the treatment of type 2 diabetes mellitus.
Zhang, Z.F.,Kim, I.H. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.3
Two experiments were conducted to determine an optimum Lys:calorie ratio (g of total dietary Lys/Mcal of DE) for growing barrows and gilts in cool and hot seasons in a commercial environment. In Exp. 1, 96 barrows and 96 gilts were randomly allocated in 1 of 4 dietary treatments (2.7, 3.0, 3.3, 3.6 g of Lys/Mcal of DE). Each treatment had 12 replicate pens with 4 pigs per pen. The experiment lasted for 34 d in the cool season (March 12th to April 15th). Diets were based on corn-wheat-soybean meal. Lys:calorie ratio were attained by adjusting the amount of corn and soybean and supplementation of crystalline Lys. Total Lys intake and available Lys intake were increased (p<.05) as dietary Lys:calorie ratio increased. The BUN concentration on d 34 for barrows, and BUN change for barrows and gilts linearly increased (p<0.05) in response to increasing dietary Lys:calorie ratio. For gilts, back fat was decreased and then increased (Quadratically, p<0.05) as increasing dietary lys:calorie ratio. Exp. 2 had a similar design as Exp. 1 with the exception that Exp. 2 was conducted in hot season (June 30th to September 11th) for 42 d. Diet of Exp. 2 was the same as Exp. 1. Total Lys intake and available Lys intake increased (p<0.05) as dietary Lys:calorie increased. On d 42, the BUN concentration increased (p<0.05) in response to the increasing dietary Lys:calorie ratio. In conclusion, dietary Lys:calorie ratio of 2.7 g of Lys/Mcal of DE could satisfy the requirement of 25 to 50 kg growing pigs. Increasing dietary Lys:calorie ratio could increase BUN concentration in growing pigs.
Intelligent hybrid controlled structures with soil-structure interaction
Zhang, X.Z.,Cheng, F.Y.,Lou, M.L. Techno-Press 2004 Structural Engineering and Mechanics, An Int'l Jou Vol.17 No.3
A hybrid control system is presented for seismic-resistant building structures with and without soil-structure interaction (SSI). The hybrid control is a damper-actuator-bracing control system composed of passive and active controllers. An intelligent algorithm is developed for the hybrid system, in which the passive damper is designed for minor and moderate earthquakes and the active control is designed to activate when the structural response is greater than a given threshold quantity. Thus, the external energy for active controller can be optimally utilized. In the control of a multistory building, the controller placement is determined by evaluating the optimal location index (OLI) calculated from six earthquake sources. In the study, the soil-structure interaction is considered both in frequency domain and time domain analyses. It is found that the interaction can significantly affect the control effectiveness. In the hybrid control algorithm with intelligent strategy, the working stages of passive and active controllers can be different for a building with and without considering SSI. Thus SSI is essential to be included in predicting the response history of a controlled structure.