Structure and Magnetic Properties for Bulk Fe<SUB>73-x</SUB>Zr₂Y₄B₂₁ Nd<SUB>x</SUB> (x=0, 2, 5, 7) Alloys Prepared by Suction Casting

X. H. Tan,H. Xu,W. J. Zhao,Q. Bai,Y. D. Dong 한국자기학회 2007 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Dependence of the properties of hydrothermally grown ZnO on precursor concentration

Zhao, X.,Lee, J.Y.,Kim, C.-R.,Heo, J.,Shin, C.M.,Leem, J.-Y.,Ryu, H.,Chang, J.-H.,Lee, H.C.,Jung, W.-G.,Son, C.-S.,Shin, B.C.,Lee, W.-J.,Tan, S.T.,Zhao, J.,Sun, X. North-Holland 2009 Physica E, Low-dimensional systems & nanostructure Vol.41 No.8

This study evaluated the effects of precursor concentration ranging from 0.06 to 1.5M on the properties of hydrothermally grown ZnO on annealed ZnO buffered Si substrates. At relatively low concentrations (no more than 0.5M), well-aligned ZnO arrays were grown on ZnO/Si(100) due to heterogeneous nucleation. As the concentration was increased to 1.0M, the morphologies changed to randomly accumulated particles as a result of homogeneous nucleation. The crystal and optical properties of the materials were investigated by X-ray diffractometer (XRD) and photoluminescence (PL) measurement, respectively. It was found that the best crystal and optical properties were obtained with concentrations of 0.5 and 0.3M, respectively. These properties were observed to degrade when the concentration was raised to more than 1.0M.

Microstructural Stability and Creep Performance of a Novel Low-Cost Single Crystal Superalloy

Z. H. Tan,X. G. Wang,Y. L. Du,Y. M. Li,Y. H. Yang,J. L. Liu,J. D. Liu,J. G. Li,Y. Z. Zhou,X. F. Sun 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The increasing pursuit of advanced aero-engines with lower ratio between the cost and performance has greatly promotedthe demanding of single crystal superalloys characterized by low cost and outstanding temperature capability. In this study,a novel low-cost single crystal superalloy was designed and the creep tests as well as micro-characterization were carried outon the experimental alloy. The results illustrated that the novel single crystal alloy exhibited an ideal microstructural stabilitywithout precipitating TCP phases, after long-term thermal exposure at the ultimate service temperature of third generationsingle crystal superalloys. Moreover, the experimental alloy with only 3 wt% Re addition demonstrated remarkable creepresistance and maintained a very low minimum creep rate at 1100 °C/137 MPa and 1120 °C/137 MPa, while the accumulationand coalescence of micro-pores had eventually led to the alloy fracture. Apart from that, the compact interfacial dislocationnetworks the 2nd γ′ phase were observed after high-temperature creep rupture, and the typical a < 010 > superdislocationswith relatively poor mobility was found at 1120 °C. At 760 °C/800 MPa, both the minimum creep velocity and entire creepstain was increased evidently, however, the ultimate creep rupture life of the alloy had still reached 200 h. The correspondingdeformation mechanism was identified as the combination of superdislocation pairs shearing and a/3 < 121 > partial dislocationcutting the γ′ phase with a SISF being generated. In general, the novel single crystal alloy characterized by remarkablemechanical properties and cost reduction possesses a great potential for future application in the advanced aircraft engines.

Effects of Buffer Layer Annealing on ZnO Thin Films Grown by using Atomic Layer Deposition

J. Y. Leem,C. R. Kim,J. H. Heo,C. M. Shin,J. H. Park,T. M. Lee,류혁현,J. H. Chang,C. S. Son,B. C. Shin,W. J. Lee,S. T. Tan,J. L. Zhao,X. W. Sun 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

In this study, the effects of buffer layer annealing duration on ZnO thin films deposited by using the remote plasma atomic layer deposition (ALD) method are discussed. ZnO thin films were grown on ZnO-buffer/Si (100) and were annealed for various durations between 0.5 and 60 min. The structural and the optical properties of the ZnO thin films were investigated by using atomic force microscopy, X-ray diffraction, and photoluminescence measurements. The ZnO thin films grown on a rough ZnO buffer layer were found to have high optical quality. The results from this study possibly contribute to advances in ZnO-base LED technologies.

Tunable room-temperature magnetic skyrmions in Ir/Fe/Co/Pt multilayers

Soumyanarayanan, Anjan,Raju, M.,Gonzalez Oyarce, A. L.,Tan, Anthony K. C.,Im, Mi-Young,Petrovi&#x107,, A. ,P.,Ho, Pin,Khoo, K. H.,Tran, M.,Gan, C. K.,Ernult, F.,Panagopoulos, C. Nature Publishing Group 2017 Nature Materials Vol.16 No.9

Magnetic skyrmions are nanoscale topological spin structures offering great promise for next-generation information storage technologies. The recent discovery of sub-100-nm room-temperature (RT) skyrmions in several multilayer films has triggered vigorous efforts to modulate their physical properties for their use in devices. Here we present a tunable RT skyrmion platform based on multilayer stacks of Ir/Fe/Co/Pt, which we study using X-ray microscopy, magnetic force microscopy and Hall transport techniques. By varying the ferromagnetic layer composition, we can tailor the magnetic interactions governing skyrmion properties, thereby tuning their thermodynamic stability parameter by an order of magnitude. The skyrmions exhibit a smooth crossover between isolated (metastable) and disordered lattice configurations across samples, while their size and density can be tuned by factors of two and ten, respectively. We thus establish a platform for investigating functional sub-50-nm RT skyrmions, pointing towards the development of skyrmion-based memory devices.

Metal-Organic Frameworks Mediate Cu Coordination for Selective CO₂ Electroreduction

Nam, Dae-Hyun,Bushuyev, Oleksandr S.,Li, Jun,De Luna, Phil,Seifitokaldani, Ali,Dinh, Cao-Thang,Garci&#x301,a de Arquer, F. Pelayo,Wang, Yuhang,Liang, Zhiqin,Proppe, Andrew H.,Tan, Chih Shan,Todorovic& American Chemical Society 2018 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.140 No.36

<P>The electrochemical carbon dioxide reduction reaction (CO<SUB>2</SUB>RR) produces diverse chemical species. Cu clusters with a judiciously controlled surface coordination number (CN) provide active sites that simultaneously optimize selectivity, activity, and efficiency for CO<SUB>2</SUB>RR. Here we report a strategy involving metal-organic framework (MOF)-regulated Cu cluster formation that shifts CO<SUB>2</SUB> electroreduction toward multiple-carbon product generation. Specifically, we promoted undercoordinated sites during the formation of Cu clusters by controlling the structure of the Cu dimer, the precursor for Cu clusters. We distorted the symmetric paddle-wheel Cu dimer secondary building block of HKUST-1 to an asymmetric motif by separating adjacent benzene tricarboxylate moieties using thermal treatment. By varying materials processing conditions, we modulated the asymmetric local atomic structure, oxidation state and bonding strain of Cu dimers. Using electron paramagnetic resonance (EPR) and in situ X-ray absorption spectroscopy (XAS) experiments, we observed the formation of Cu clusters with low CN from distorted Cu dimers in HKUST-1 during CO<SUB>2</SUB> electroreduction. These exhibited 45% C<SUB>2</SUB>H<SUB>4</SUB> faradaic efficiency (FE), a record for MOF-derived Cu cluster catalysts. A structure-activity relationship was established wherein the tuning of the Cu-Cu CN in Cu clusters determines the CO<SUB>2</SUB>RR selectivity.</P> [FIG OMISSION]</BR>

Effects of Rice Straw Particle Size on Chewing Activity, Feed Intake, Rumen Fermentation and Digestion in Goats

Zhao, X.G.,Wang, M.,Tan, Z.L.,Tang, S.X.,Sun, Z.H.,Zhou, C.S.,Han, X.F. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.9

Effects of particle size and physical effective fibre (peNDF) of rice straw in diets on chewing activities, feed intake, flow, site and extent of digestion and rumen fermentation in goats were investigated. A 4${\times}$4 Latin square design was employed using 4 mature Liuyang black goats fitted with permanent ruminal, duodenal, and terminal ileal fistulae. During each of the 4 periods, goats were offered 1 of 4 diets that were similar in nutritional content but varied in particle sizes and peNDF through alteration of the theoretical cut length of rice straw (10, 20, 40, and 80 mm, respectively). Dietary peNDF contents were determined using a sieve for particle separation above 8 mm, and were 17.4, 20.9, 22.5 and 25.4%, respectively. Results showed that increasing the particle size and peNDF significantly (p<0.05) increased the time spent on rumination and chewing activities, duodenal starch digestibility and ruminal pH, and decreased ruminal starch digestibility and $NH_{3}$-N concentration. Intake and total tract digestibility of nutrients (i.e. dry matter, organic matter, and starch) and ruminal fermentation were not affected by the dietary particle size and peNDF. Increased particle size and peNDF did not affect ruminal fibre digestibility, but had a great impact on the intestinal and total tract fibre digestibility. The study suggested that rice straw particle size or dietary peNDF was the important influential factor for chewing activity, intestinal fibre and starch digestibility, and ruminal pH, but had minimal impact on feed intake, duodenal and ileal flow, ruminal and total tract digestibility, and ruminal fermentation.

Use of In vitro Gas Production Technique to Investigate Interactions between Rice Straw, Wheat Straw, Maize Stover and Alfalfa or Clover

Tang, S.X.,Tayo, G.O.,Tan, Z.L.,Sun, Z.H.,Wang, M.,Ren, G.P.,Han, X.F. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.9

Measurement of gas produced during in vitro fermentation was used to investigate the fermentation characteristics and interactions of rice straw, wheat straw or maize stover mixed with alfalfa or clover at proportions of 100:0, 75:25, 50:50, 25:75 and 0:100, respectively. Cumulative gas production was recorded at 2, 4, 8, 12, 16, 24 and 48 h of incubation, and the Gompertz function was used to describe the kinetics of gas production. In vitro dry matter and organic matter disappearances (IVDMD and IVOMD) were determined after 48 h incubation. The rate of gas production of clover was higher (p<0.05) than that of rice straw, wheat straw, maize stover and alfalfa when straws and hays were incubated separately. Increasing the proportion of alfalfa in the straw-alfalfa mixtures increased (p<0.05) the rates, but not the maximum volume of gas production. However, both rate and the maximum volume of gas production were increased (p<0.01) as the proportions of clover increased in the straw-clover mixtures. The cumulative gas production at 48 h, IVDMD and IVOMD showed no consistent interaction effects between different mixtures of cereal straws and hays. The extent of interactive effects was affected by the types of cereal straw, legume hay and their proportions in the mixture. The appropriate combination for the mixture of rice straw or maize stover with leguminous hays was 75:25 and 25:75, respectively. The better combination occurred at a proportion of 50:50 for the mixture of wheat straw and alfalfa. We conclude that the suitable proportion of low-quality straw and high quality legume hay combination should be considered in the ration formulation system of ruminants according to the extent of positive interactive effects.

Substitution of Wheat for Corn in Beef Cattle Diets: Digestibility, Digestive Enzyme Activities, Serum Metabolite Contents and Ruminal Fermentation

Liu, Y.F.,Zhao, H.B.,Liu, X.M.,You, W.,Cheng, H.J.,Wan, F.C.,Liu, G.F.,Tan, X.W.,Song, E.L.,Zhang, X.L. Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.10

The objective of this study was to evaluate the effect of diets containing different amounts of wheat, as a partial or whole substitute for corn, on digestibility, digestive enzyme activities, serum metabolite contents and ruminal fermentation in beef cattle. Four Limousin${\times}$LuXi crossbred cattle with a body weight ($400{\pm}10kg$), fitted with permanent ruminal, proximal duodenal and terminal ileal cannulas, were used in a $4{\times}4$ Latin square design with four treatments: Control (100% corn), 33% wheat (33% substitution for corn), 67% wheat (67% substitution for corn), and 100% wheat (100% substitution for corn) on a dry matter basis. The results showed that replacing corn with increasing amounts of wheat increased the apparent digestibility values of dry matter, organic matter, and crude protein (p<0.05). While the apparent digestibility of acid detergent fiber and neutral detergent fiber were lower with increasing amounts of wheat. Digestive enzyme activities of lipase, protease and amylase in the duodenum were higher with increasing wheat amounts (p<0.05), and showed similar results to those for the enzymes in the ileum except for amylase. Increased substitution of wheat for corn increased the serum alanine aminotransferase concentration (p<0.05). Ruminal pH was not different between those given only corn and those given 33% wheat. Increasing the substitution of wheat for corn increased the molar proportion of acetate and tended to increase the acetate-to-propionate ratio. Cattle fed 100% wheat tended to have the lowest ruminal $NH_3-N$ concentration compared with control (p<0.05), whereas no differences were observed among the cattle fed 33% and 67% wheat. These findings indicate that wheat can be effectively used to replace corn in moderate amounts to meet the energy and fiber requirements of beef cattle.

Effect of Ru additions on very high temperature creep properties of a single crystal Ni-based superalloy

Tan, X.P.,Liu, J.L.,Jin, T.,Hu, Z.Q.,Hong, H.U.,Choi, B.G.,Kim, I.S.,Jo, C.Y.,Mangelinck, D. Elsevier Sequoia 2013 Materials science & engineering. properties, micro Vol.580 No.-

The creep deformation of three single crystal Ni-based superalloys with various Ru contents has been investigated to clarify the effect of Ru additions at very high temperatures and low stresses conditions. The creep properties were significantly improved by Ru additions under the conditions of 1150<SUP>o</SUP>C/100MPa and 1180<SUP>o</SUP>C/70MPa. It is noted that obvious γ' phase dissolution occurs during the entire creep deformation at very high temperatures. It differs from the typical high-temperature creep curves that a short incubation period occurs before the primary creep stage during the creep deformation at very high temperatures. Ru additions are able to produce denser interfacial dislocation networks and improve the stability and homogeneous configuration of interfacial dislocations; and promote the high-temperature stability of γ' phase and formation of perfect γ' rafting. It is thus shown that Ru additions reduce the minimum creep rate, and prolong the secondary creep stage accordingly. The topological inversion of γ/γ' microstructure did not occur under both conditions. The origin of the rapid increase of creep rate is closely relevant to the unstable propagation of micro-cracks in the vicinity of porosity in necked regions.