Temporal-spatial structures of plasmas flows and turbulence around tearing mode islands in the edge tokamak plasmas

Zhao, K.J.,Nagashima, Y.,Li, F.M.,Shi, Yuejiang,Diamond, P.H.,Dong, J.Q.,Itoh, K.,Itoh, S.-I.,Zhuang, G.,Liu, H.,Chen, Z.P.,Cheng, J.,Nie, L.,Ding, Y.H.,Hu, Q.M.,Chen, Z.Y.,Rao, B.,Cheng, Z.F.,Gao, L. IOP 2017 Nuclear fusion Vol.57 No.12

<P>The temporal-spatial structures of plasma flows and turbulence around tearing mode islands are presented. The experiments were performed using Langmuir probe arrays in the edge plasmas of J-TEXT tokamak. The correlation analyses clearly show that the flows have similar structures of <I>m</I>/<I>n</I>  =  3/1 as the magnetic island does (<I>m</I> and <I>n</I> are the poloidal and toroidal mode numbers, respectively). The sign of the potential fluctuations for the flows inverses and the powers significantly reduce at <I>q</I>  =  3 surface. Approaching to the last closed flux surface for the magnetic islands, the radially elongated flow structure forms. The flows are concentrated near separatrix and show quadrupole structures. The turbulence is concentrated near X-point and partly trapped inside the magnetic islands.</P>

Tests and finite element analysis on the local buckling of 420 MPa steel equal angle columns under axial compression

G. Shi,Z. Liu,H.Y. Ban,Y. Zhang,Y.J. Shi,Y.Q. Wang 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.12 No.1

Local buckling can be ignored for hot-rolled ordinary strength steel equal angle compression members, because the width-to-thickness ratios of the leg don’t exceed the limit value. With the development of steel structures, Q420 high strength steel angles with the nominal yield strength of 420 MPa have begun to be widely used in China. Because of the high strength, the limit value of the width-to-thickness ratio becomes smaller than that of ordinary steel strength, which causes that the width-to-thickness ratios of some hot-rolled steel angle sections exceed the limit value. Consequently, local buckling must be considered for 420 MPa steel equal angles under axial compression. The existing research on the local buckling of high strength steel members under axial compression is briefly summarized, and it shows that there is lack of study on the local buckling of high strength steel equal angles under axial compression. Aiming at the local buckling of high strength steel angles, this paper conducts an axial compression experiment of 420MPa high strength steel equal angles, including 15 stub columns. The test results are compared with the corresponding design methods in ANSI/AISC 360-05 and Eurocode 3. Then a finite element model is developed to analyze the local buckling behavior of high strength steel equal angles under axial compression, and validated by the test results. Followingthe validation, a finite element parametric study is conducted to study the influences of a range of parameters, and the analysis results are compared with the design strengths by ANSI/AISC 360-05 and Eurocode 3.

Enhanced energy storage properties in PbZrO3 thin films via the incorporation of NiO

Wang X.W.,Chen J.Y.,Hu S.Y.,Yu K.X.,Yang F.,Shi Y.J.,Li J.H.,Hou M.Z.,Liu A.D.,Zheng M.M.,Yin S.Q.,Hu Y.C.,Shang J. 한국물리학회 2023 Current Applied Physics Vol.52 No.-

In this study, NiO–PbZrO3 composite films were deposited on SiO2/Si substrates buffered with LaNiO3 films via the sol-gel coating technique. The effects of NiO addition in PZO thin films on the microstructure, dielectric properties, leakage mechanism, ferroelectric properties and energy storage properties have been discussed. The dielectric constant increased with the addition of NiO, while the leakage current density decreased. Compared with pure PZO films, the maximum polarization of the composite films was improved. For the composite films prepared using the NiO precursor solution with 0.05 mol/L, the recoverable energy storage density of the NiO-PZO composite film is up to 19.6 J/cm3 under the electric field of 1038 kV/cm, which is 30% higher than that of the pure PZO film under the same conditions. Also, the energy storage efficiency of the composite film reaches 48%. Accordingly, we demonstrate a simple and convenient method by adding NiO to fabricate thin films with high energy storage performance.

An approach to bioassess pelagic ciliate biodiversity at different taxonomic resolutions in response to various habitats in the Amundsen Sea (Antarctica)

Jiang, Y.,Liu, Q.,Yang, E. J.,Wang, M.,Lee, Y.,Lee, S. Springer Science + Business Media 2016 Polar biology Vol.39 No.3

<P>The rapid melting of glaciers and loss of sea ice will result in changes in habitat conditions that may drive substantial changes in biodiversity. In order to bioassess the changing polar ecosystem and evaluate biological conservation, pelagic ciliate communities at different taxonomic resolutions were studied at five habitats in the Amundsen Sea during the austral summer from December 2010 to January 2011. Distinctive spatial patterns were observed in the communities among the five habitats (oceanic areas, transitional areas, polynyas, edges of glaciers, and edges of sea ice) in response to environmental variability (e.g., temperature, salinity, chlorophyll a, and nutrients). The distributions in the numbers of different taxonomic levels and of three biodiversity indices (Shannon-Wiener H', Pielou's J', and Margalef D) also revealed clear spatial variability with the maximum mean species number and indices in the polynya and maximum genus and family numbers in the transitional area. The presence/absence of data at taxonomic resolutions up to the family level provided sufficient information to evaluate the ecological patterns of pelagic ciliate communities and could accurately reflect habitat variations. The k-dominance curves illustrated clearly that maximum diversity was presented in the polynya at the species level and in the transitional area at the genus and family level. We suggest that the diversity at higher taxonomic resolutions should be considered more in future monitoring. Our findings provide basic data and an approach toward answering important questions about biological conservation, especially the biodiversity at various taxonomic resolutions in response to the increasing climate changes in polar ecosystems.</P>

3D Atom Probe Characterization of Temporal Evolution of Precipitates in Aging Nb-V Micro-Alloyed Steel

Q.D.Liu,W.Q.Liu,S.J.Zhao 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.6

A 3D atom probe combined with TEM was applied to characterize carbides precipitation in Nb-V microalloyed steel aging at 550 °C for different times after being water-quenched from 1200 °C. The results indicated that the V- and Nb-containing ultra-fine carbides obtained by 4 h aging had the highest number density and moderate sizes, resulting in a peak precipitation strengthening value. C, V and Nb firstly co-segregated to form nano-sized clusters at the initial stage of precipitation, and then contributed to the formation of composition-steady carbides as the aging time was prolonged.

Investigation of Sub-10-nm Diameter, Gate-All-Around Nanowire Field-Effect Transistors for Electrostatic Discharge Applications

Liu, W,Liou, J J,Jiang, Y,Singh, N,Lo, G Q,Chung, J,Jeong, Y H IEEE 2010 IEEE TRANSACTIONS ON NANOTECHNOLOGY Vol.9 No.3

<P>Electrostatic discharge (ESD) robustness of a promising nanoscaled device, the gate-all-around nanowire field-effect transistor (NW FET), was characterized for the first time using the transmission-line pulsing technique. The effects of gate length, nanowire dimension, and nanowire count on the failure current, leakage current, trigger voltage, and on-resistance were investigated. ESD performances of the gate-all-around NW FET and other nanostructure devices, such as the poly-Si nanowire thin-film transistor and FinFET were also compared and discussed.</P>

HIGH-PERFORMANCE Pt/CNTs CATALYSTS VIA HYDROGEN PLASMA FOR METHANOL ELECTROOXIDATION

J. L. XU,S. G. WANG,Q. R. DENG,Y. LIU,J. L. ZHU,C. B. XU,J. H. WANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.2

High-performance carbon nanotubes-supported Pt catalysts (Pt/CNTs) catalysts were pre-pared on the basis of Pt precursors reduced by hydrogen plasma (Pt/CNTs-HP) generated bymicrowave. The other two Pt/CNTs catalysts prepared by hydrogen (Pt/CNTs-H) and NaBH 4(Pt/CNTs-N) reduction were also involved for comparison. The practical composition of thecatalysts was characterized with energy dispersive analysis of X-ray (EDAX). It was shown fromtransmission electron microscopy (TEM) and X-ray di®raction (XRD) that the Pt nanoparticlesin Pt/CNTs-HP were uniformly dispersed on CNTs with smaller particle size around 2 nmand narrower size distribution as compared with the other two catalysts. Additionally, X-rayphotoelectron spectrum (XPS) analysis indicated higher amount of zero-valence states of Pt inPt/CNTs-HP caused by hydrogen plasma treatment. The electrooxidation of liquid methanol onthese catalysts was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV)and chronoamperometry. The long-time durability is very comparable to all the three catalysts. Remarkably, the Pt/CNTs-HP possessed the highest electrocatalytic activity, suggesting thatthe hydrogen plasma reduction approach can be a promising reduction method for preparinghigh-performance Pt-based electrocatalysts.

The spectral characterization of ∼-graphs

Liu, F.,Huang, Q.,Wang, J.,Liu, Q. North Holland [etc.] 2012 Linear Algebra and its Applications Vol. No.

A ∼-graph B(r,s) is a graph consisting of two cycles C<SUB>r+1</SUB> and C<SUB>s+1</SUB> with just a vertex in common. Fan and Luo in Theorem 4.4 [8] alleged that a ∼-graph is determined by its adjacency spectrum if it contains no cycle C<SUB>4</SUB>. However, according to Theorem 6.3 [16] we find that the result in Theorem 4.4 [8] is not completely correct. In this paper, we prove that B(r,s)(s>=r>7) is DAS if and only if s<>=r+2, and B(r,s)(s>=r>7) has a unique cospectral mate if s=r+2.

Nutritional Evaluation of Bamboo Shoot Shell and Its Effect as Supplementary Feed on Performance of Heifers Offered Ammoniated Rice Straw Diets

Liu, J.X.,Wang, X.Q.,Shi, Z.Q.,Ye, H.W. Asian Australasian Association of Animal Productio 2000 Animal Bioscience Vol.13 No.10

The present study was conducted to examine the feasibility of utilising bamboo (Bambusa arundinacea) shoot shell (BSS) in ruminants. Chemical composition, rumen degradability and some antinutritional compounds were determined for fresh and boiled BSSs to evaluate its feed value and safety. Thirty-two Holstein heifers were allocated to four groups and used to investigate the response in growth rate to supplementing ammoniated rice straw with fresh shell (phase 1) or silage of boiled BSS (phase 2). All animals were offered ammoniated straw ad libitum with 1kg of cotton seed meal (phase 1) or 0.5 kg of cotton seed meal and 0.5 kg of concentrate mixture (phase 2) per head per day. The BSS was supplemented at levels of 0, 3, 6 or 9 kg/d (phase 1) and 0, 5, 10 or 15 kg/d (phase 2) (as fed basis). The BSS was very high in moisture content, and its contents of crude protein and neutral detergent fiber were 13~16% DM and 65~76% DM, respectively; boiling resulting in higher moisture and protein. No hydrocyanic acid was detected in both BSSs and content of tannins was negligible. Rumen degradability of BSS was reasonably high, and with boiling the rapidly degradable fraction decreased, and potentially degradable component increased. Silage of the boiled BSS was slightly lower in both rapidly and slowly degraded fractions than the fresh BSS. Animals consumed all supplemented BSSs without any adverse health problems. Intake of ammoniated straw decreased with the increasing levels of BSS, but total intake was higher in almost all supplementary groups than in the non-BSS. Heifers had a higher growth rate in phase 1 with fresh BSS than in phase 2 with ensiled shell, and daily weight gains were 622, 629, 744 or 690 g in phase 1, and 578, 575, 677 or 635 g in phase 2 at four BSS levels, respectively. For both phases growth rate was significantly higher for the animals in groups 3 and 4 than those in groups 1 and 2 (p<0.01), with little difference between groups 1 and 2 (p>0.05) but significant difference between groups 3 and 4 (p<0.05). Supplementation with BSS also resulted in an improved feed conversion rate, with the least concentrate consumption in group 3 for both phases. It is concluded that the BSS has a high potential nutritional value as indicated by its medium protein content, reasonably high rumen degradability, and that inclusion of BSS in ammoniated rice straw diet is not only safe to animals, but also may improve growth rate of ruminants and feed conversion rate. It may be disadvantageous to use high amounts of BSS in ammoniated straw diets.

Photocatalytic and Hydrophilic Properties of TiO₂/ Fe₂O₃ Composite Films

Q. J. Liu,Q. L,X. H. Wu,G. Q. Zhang,Z. Q. Gao,G. X. Chen 한국진공학회(ASCT) 2002 Journal of Korean Vacuum Science & Technology Vol.6 No.1

TiO₂/Fe₂O₃ composite thin films were prepared on common glass substrates by sol-gel processing and dip-drawing method. The effect of Fe₂O₃ content on the photocatalytic and hydrophilic properties of composite films was studied. The results indicate that the photocatalytic activities of composite TiO₂ films are superior to that of pure TiO₂ film, and the film containing 0.5% Fe₂O₃ has the best photocatalytic activity. The hydrophilicity is difference with variant Fe₂O₃ content, the films containing 0.05%~0.1% Fe₂O₃ have the best hydrophilicity and their contact angles are 0°.