Complex Multicolor Tilings and Critical Phenomena in Tetraphilic Liquid Crystals

Zeng, X.,Kieffer, R.,Glettner, B.,Nurnberger, C.,Liu, F.,Pelz, K.,Prehm, M.,Baumeister, U.,Hahn, H.,Lang, H.,Gehring, G. A.,Weber, C. H. M.,Hobbs, J. K.,Tschierske, C.,Ungar, G. American Association for the Advancement of Scienc 2011 Science Vol.331 No.6022

<P>T-shaped molecules with a rod-like aromatic core and a flexible side chain form liquid crystal honeycombs with aromatic cell walls and a cell interior filled with the side chains. Here, we show how the addition of a second chain, incompatible with the first (X-shaped molecules), can form honeycombs with highly complex tiling patterns, with cells of up to five different compositions ('colors') and polygonal shapes. The complexity is caused by the inability of the side chains to separate cleanly because of geometric frustration. Furthermore, a thermoreversible transition was observed between a multicolor (phase-separated) and a single-color (mixed) honeycomb phase. This is analogous to the Curie transition in simple and frustrated ferro- and antiferromagnets; here spin flips are replaced by 180° reorientations of the molecules.</P>

Insights into the Early Growth of Homogeneous Single-Layer Graphene over Ni–Mo Binary Substrates

Ru&#x308,mmeli, Mark H.,Zeng, Mengqi,Melkhanova, Svetlana,Gorantla, Sandeep,Bachmatiuk, Alicja,Fu, Lei,Yan, Chenglin,Oswald, Steffen,Mendes, Rafael G.,Makarov, Denys,Schmidt, Oliver,Eckert, Ju&#x308,r American Chemical Society 2013 Chemistry of materials Vol.25 No.19

<P>The employment of Ni–Mo films has recently been shown to yield strictly homogeneous single-layer graphene. In this study, we systematically investigate the different stages of nucleation and growth of graphene over Ni–Mo layers. The studies reveal that the Ni film breaks up and diffuses into the underlying Mo foil, forming a Ni–Mo intermetallic. Nucleation only occurs from Ni sites, and thus, the nucleation density can be controlled by the Ni film thickness. Both nucleation and growth of the graphene are shown to be susceptible to very efficient self-termination processes to the formation of molybdenum carbide, and this guarantees the formation of large area graphene that consists <I>entirely</I> of monolayer graphene.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2013/cmatex.2013.25.issue-19/cm4020783/production/images/medium/cm-2013-020783_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm4020783'>ACS Electronic Supporting Info</A></P>

Strain induced hardening and softening behaviors of deformed Cu and Cu-Ge alloys

Gong, Y.L.,Kim, H.S.,Ren, S.Y.,Zeng, S.D.,Zhu, X.K. Published for the Materials Research Society by th 2016 Journal of materials research Vol.31 No.5

<▼1><B>Abstract</B><P/></▼1><▼2><P>Herein, Cu and Cu-Ge alloys with different stacking fault energies (SFEs) are prepared via rolling at room temperature (RTR) and via a combination of high-pressure torsion (HPT) and RTR (HPT + RTR). The x-ray diffraction measurements reveal that the grain size, dislocation density, and twin density vary with the strain and SFEs. The tensile tests indicate that the strength of materials with medium SFEs increases initially and then slightly declines, while the ductility is enhanced by increasing the strain via HPT. In contrast, for low-SFE materials, enhanced strength and improved ductility may be achieved simultaneously through increasing the strain to a high level. The variation of strength with respect to strain is primarily dependent on the solute concentration and SFE. The underlying mechanisms governing the effect of strain and SFE on the microstructures and mechanical properties of the metals are also discussed.</P></▼2>

Hyperoside protects primary rat cortical neurons from neurotoxicity induced by amyloid β-protein via the PI3K/Akt/Bad/Bcl_XL-regulated mitochondrial apoptotic pathway

Zeng, K.W.,Wang, X.M.,Ko, H.,Kwon, H.C.,Cha, J.W.,Yang, H.O. North-Holland ; Elsevier Science Ltd 2011 european journal of pharmacology Vol.672 No.1

Amyloid β-protein (Aβ), which is deposited in neurons as neurofibrillary tangles, is known to exert cytotoxic effects by inducing mitochondrial dysfunction. Additionally, the PI3K/Akt-mediated interaction between Bad and Bcl<SUB>XL</SUB> plays an important role in maintaining mitochondrial integrity. However, the application of therapeutic drugs, especially natural products in Alzheimer's disease therapy via PI3K/Akt/Bad/Bcl<SUB>XL</SUB>-regulated mitochondrial apoptotic pathway has not aroused extensive attention. In the present study, we investigated the neuroprotective effects of hyperoside, a bioactive flavonoid compound from Hypericum perforatum, on Aβ<SUB>25-35</SUB>-induced primary cultured cortical neurons, and also examined the potential cellular signaling mechanism for Aβ detoxication. Our results showed that treatment with hyperoside significantly inhibited Aβ<SUB>25-35</SUB>-induced cytotoxicity and apoptosis by reversing Aβ-induced mitochondrial dysfunction, including mitochondrial membrane potential decrease, reactive oxygen species production, and mitochondrial release of cytochrome c. Further study indicated that hyperoside can activate the PI3K/Akt signaling pathway, resulting in inhibition of the interaction between Bad and Bcl<SUB>XL</SUB>, without effects on the interaction between Bad and Bcl-2. Furthermore, hyperoside inhibited mitochondria-dependent downstream caspase-mediated apoptotic pathway, such as that involving caspase-9, caspase-3, and poly ADP-ribose polymerase (PARP). These results demonstrate that hyperoside can protect Aβ-induced primary cultured cortical neurons via PI3K/Akt/Bad/Bcl<SUB>XL</SUB>-regulated mitochondrial apoptotic pathway, and they raise the possibility that hyperoside could be developed into a clinically valuable treatment for Alzheimer's disease and other neuronal degenerative diseases associated with mitochondrial dysfunction.

Effects of Dietary Lysine Levels on Apparent Nutrient Digestibility and Serum Amino Acid Absorption Mode in Growing Pigs

Zeng, P.L.,Yan, H.C.,Wang, X.Q.,Zhang, C.M.,Zhu, C.,Shu, G.,Jiang, Q.Y. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.7

Two experiments were conducted to determine the effects of different dietary lysine levels on the apparent nutrient digestibility, the serum amino acid (AA) concentration, and the biochemical parameters of the precaval and portal vein blood in growing pigs. In Experiment 1, 15 noncannulated pigs received diets with different lysine densities (0.65%, 0.95%, and 1.25% lysine) for 13 d. A total collection digestion test was performed, and blood samples were collected from the precaval vein at the end of the experiment. In Experiment 2, four cannulated pigs were fed the same diets of Experiment 1. The experiment used a self-control experimental design and was divided into three periods. On d 5 of each period, at 0.5 h before feeding and hourly up to 8 h after feeding, single blood samples were collected from catheters placed in the portal vein. In Experiment 1, some serum AAs (including lysine), serum urinary nitrogen (SUN), and total protein (TP) concentrations were significantly affected by the dietary lysine levels (p<0.05). Moreover, the 0.65% lysine treatment showed a significant lower apparent digestibility of gross energy, dry matter, crude protein, and phosphorus than the other treatments (p<0.05). In Experiment 2, serum lysine, histidine, phenylalanine, threonine, valine, isoleucine (p = 0.0588), triglyceride, and SUN (p = 0.0572) concentrations were significantly affected by the dietary lysine levels (p<0.05). Additionally, almost all of the determined serum AA and total AA concentrations reached their lowest values at 0.5 h before feeding and their highest values at 2 h after feeding (p<0.05). These findings indicate that the greatest absorption of AA occurred at 2 h after feeding and that the dynamic profile of serum AA is affected by the dietary lysine levels. Moreover, when the dietary lysine content was 0.95%, the growing pigs achieved a better nutrient digestibility and serum metabolites levels.

Clarifying the basic phase structure and magnetic behavior of directly quenched (Ce,La)2Fe14B alloys with various Ce/La ratios

X.F. Liao,L.Z. Zhao,J.S. Zhang,G. Ahmed,A.J. Khan,H.X. Zeng,H.Y. Yu,X.C. Zhong,Z.W. Liu,G.Q. Zhang 한국물리학회 2019 Current Applied Physics Vol.19 No.6

To improve the performance/cost ratio of NdFeB based permanent magnets, Ce or/and La substitutions for Nd have been suggested. To better understand the effects of these substitutions, the fundamental behavior of (Ce,La)-Fe-B alloys has to be clearly understood. Here, we reported a systematic investigation on the phase structure, microstructure, and magnetic properties of melt-spun (Ce,La)2Fe14B alloys. The results confirm that partial substitution of Ce by La can effectively enhance the hard magnetism and thermal stability of (Ce1- xLax)2Fe14B alloys, while over 80% La substitution leads to the decomposition of 2:14:1 phase. The lattice parameters a, c and the Curie temperature Tc of 2:14:1 phase increase linearly with the increasing La content. La substitution can effectively refine the grain, resulting in the enhancement of inter-grain exchange coupling. The (Ce0.7La0.3)2Fe14B alloy with a mean grain size of 25 nm exhibits high remanence, maximum energy product and intrinsic coercivity up to 0.69 T, 6.2 MGOe and 217 kA/m, respectively. The present work provides a good understanding on the melt-spun (Ce,La)-Fe-B system for further developing low cost rare earth permanent magnets.

432-μm Laser’s Beam-waist Measurement for the Polarimeter/Interferometer on the EAST Tokamak

Z. X. Wang,H. Q. Liu,Y. X. Jie,M. Q. Wu,T. Lan,X. Zhu,Z. Y. Zou,Y. Yang,X. C. Wei,L. Zeng,G. S. Li,X. Gao 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.8

A far-infrared (FIR) polarimeter/interferometer (PI) system is under development for measurementsof the current-density and the electron-density profiles in the EAST tokamak. The systemwill utilize three identical 432-μm CHCOOH lasers pumped by a CO2 laser. Measurements of thelaser beam’s waist size and position are basic works. This paper will introduce three methods witha beam profiler and several focusing optical elements. The beam profiler can be used to show thespatial energy distribution of the laser beam. The active area of the profiler is 12.4 × 12.4 mm2. Some focusing optical elements are needed to focus the beam in order for the beam profiler toreceive the entire laser beam. Two principles and three methods are used in the measurement. Thefirst and the third methods are based on the same principle, and the second method adopts an otherprinciple. Due to the fast and convenient measurement, although the first method is a special formof the third and it can only give the size of beam waist, it is essential to the development of theexperiment and it can provide guidance for the choices of the sizes of the optical elements in the nextstep. A concave mirror, a high-density polyethylene (HDPE) lens and a polymethylpentene (TPX)lens are each used in the measurement process. The results of these methods are close enough forthe design of PI system’s optical path.

Development of the 3.7 GHz LHCD System on HL-2A

B. Lu,M. Huang,H. Zeng,X. Y. Bai,X. H. Mao,Z. H. Lu,J. Liang,Z. H. Kang,M. W. Wang,K. Feng,H. Wang,C. Wang,J. Q. Wang,S. Wei,T. Yao,Y. N. Bu,J. Feng,G. Y. Cheng,S. D. Song,D. H. Xia,J. Rao 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.8

A 2 MW-3.7 GHz lower hybrid current drive (LHCD) system is under development for physicsexperiments on the HL-2A device. The RF Power is generated by four TH2103A klystron amplifiersand propagates in the TE10 mode through WR284 waveguides. The transmission lines with a lengthof 20 m to 30 m are pressurized with 2 bars of nitrogen to decrease the possibility of arcing. Thelauncher, based on the passive-active multi-junction (PAM) concept, has been developed and iscurrently being realized. It was designed for a power spectrum peaked at Nk = 2.75 with goodcoupling properties over a wide range of plasma parameters. The four klystrons are fed by ahigh-voltage power supply (HVPS) based on the pulse step modulation (PSM) concept with a fastswitch-off time of less than ten μs. This system is expected to be in operation within 1 years and willexplore many international thermonuclear experimental reactor (ITER) related LH experiments inthe following years.

Effects of Adding Super Dose Phytase to the Phosphorus-deficient Diets of Young Pigs on Growth Performance, Bone Quality, Minerals and Amino Acids Digestibilities

Zeng, Z.K.,Wang, D.,Piao, X.S.,Li, P.F.,Zhang, H.Y.,Shi, C.X.,Yu, S.K. Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.2

Two experiments were conducted to evaluate the efficacy of feeding an Escherichia coli (E. coli) derived phytase to pigs fed P deficient, corn-soybean meal diets. In Exp. 1, one hundred and twenty crossbred piglets ($9.53{\pm}0.84$ kg) were allocated to one of five treatments which consisted of four low P diets (0.61% Ca, 0.46% total P and 0.24% non-phytate P) supplemented with 0, 500, 1,000, or 20,000 FTU/kg E. coli phytase as well as a positive control formulated to be adequate in all nutrients (0.77% Ca, 0.62% total P and 0.42% non-phytate P). The treatments were applied to six pens with four pigs per pen for 28 days. In Exp. 2, ten crossbred pigs ($19.66{\pm}1.16$ kg) fitted with ileal T-cannula were used in a nutrient balance study. The pigs were assigned to treatments similar to those used in Exp. 1 in a doubly replicated $5{\pm}4$ incomplete Latin square design (5 diets with 4 periods). Each period consisted of a 5-d adjustment period followed by a 3-d total collection of feces and urine and then a 2-d collection of ileal digesta. Supplementation with phytase linearly increased (p<0.05) weight gain, feed intake, feed efficiency, bone breaking strength and fat-free dry and ash bone weight. There were linear increases (p<0.01) in the apparent ileal digestibility (AID) of DM, GE, CP, Ca, total P, inositol hexaphosphate ($IP_6$) and some AA with increasing dose of E. coli phytase. Pigs fed 20,000 FTU/kg had a greater (p<0.05) AID of IP6 (80% vs 59% or 64%, respectively) than pigs fed diets with 500 or 1,000 FTU/kg phytase. There were linear increases (p<0.05) in the total tract digestibility of Ca, total P, Na, K, Mg, and Zn as well as in the retention of Mg and Zn with increased phytase dose. The retention and utilization of Cu, and the total tract digestibility of CP and Cu quadratic increased (p<0.05) with increased phytase dose. In conclusion, supplementation of 500 FTU of phytase/kg and above effectively hydrolyzed phytate in low-P corn-soybean diets for pigs. In addition, a super dose of phytase (20,000 FTU/kg) hydrolyzed most of the IP6 and consequently further improved mineral use, protein utilization and performance.

NONLINEAR ANALYSIS OF SELF-EXCITED VIBRATION IN WHEELED TRACTOR VEHICLE’S DRIVELINE

X.-H. LI,J.-W. ZHANG,C.-C. ZENG 한국자동차공학회 2006 International journal of automotive technology Vol.7 No.5

A nonlinear analysis of torsional self-excited vibration in the driveline system for wheeled towing tractors was presented, with a 2-DOF mathematical model. The vibration system was described as a second-order ordinary differential equation. An analytical approach was proposed to the solution of the second-order ODE. The mathematical neighborhood concept was used to construct the interior boundary and the exterior boundary. The ODE was proved to have a limit cycle by using Poincare-Bendixson Annulus Theorem when two inequalities were satisfied. Because the two inequalities are easily satisfied, the self-excited vibration is inevitable and even the initial slip rate is little. However, the amplitude will be almost zero when the third inequality is satisfied. Only in a few working modes of the towing tractor the third inequality is not satisfied. It is shown by experiments that the torsional self-excited vibration in the driveline of the vehicle is obvious.