Effects of Neodymium and Calcium on the Thermal Stability of AZ71 Magnesium Alloys

Cheng‑Feng Yue,Shi‑Jei Huang,Jhewn‑Kuang Chen,Hsien‑Tsung Li,Kam‑Shau Chan 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.2

The effects of an addition of 0–2 wt% Nd on thermal stability of 0–3 wt% Ca-containing modified AZ71 magnesium alloyswas investigated. The ignition temperature was found to increase from that of AZ71, 574, to 825 °C with the addition of0.5 wt% Ca and 1 wt% Nd. The ignition temperature was further increased to 1114 °C when 3 wt% Ca was added. The CaandNd-added AZ71 was isothermally maintained at a temperature of 500 °C in air for 12 h. The MgO–CaO–Nd2O3 formedon the surface to improve the thermal stability of the AZ71–xCa–yNd alloys. While both the tensile strength and ductilitydecreased with the Ca concentration in the alloy, an addition of 1 wt% Nd was found able to alleviate the degradation effectsof Ca on the tensile strength and ductility at 170 °C. Both solid solution formation and precipitation strengthening contributedto the increase in toughness. AZ71 containing 0.5–2 wt% Ca and 1 wt% Nd provides the optimum combination of ignitionresistance and mechanical properties.

An Agent Gaming and Genetic Algorithm Hybrid Method for Factory Location Setting and Factory/Supplier Selection Problems

Feng-Cheng Yang,Shih-Lin Kao 대한산업공학회 2009 Industrial Engineeering & Management Systems Vol.8 No.4

This paper first presents two supply chain design problems: 1) a factory location setting and factory selection problem, and 2) a factory location setting and factory/supplier selection problem. The first involves a number of location known retailers choosing one factory to supply their demands from a number of factories whose locations are to be determined. The goal is to minimize the transportation and manufacturing cost to satisfy the demands. The problem is then augmented into the second problem, where the procurement cost of the raw materials from a chosen material supplier (from a number of suppliers) is considered for each factory. Economic beneficial is taken into account in the cost evaluation. Therefore, the partner selections will influence the cost of the supply chain significantly. To solve these problems, an agent gaming and genetic algorithm hybrid method (AGGAHM) is proposed. The AGGAHM consecutively and alternatively enable and disable the advancement of agent gaming and the evolution of genetic computation. Computation results on solving a number of examples by the AGGAHM were compared with those from methods of a general genetic algorithm and a mutual frozen genetic algorithm. Results showed that the AGGAHM outperforms the methods solely using genetic algorithms. In addition, various parameter settings are tested and discussed to facilitate the supply chain designs.

“Let’s Kill All the Lawyers” : Legal Illegalities in The Merchant of Venice

Cheng Feng 행정언어와 질적연구학회 2014 행정언어와 질적연구 Vol.5 No.1

Based on the assumption that Shakespeare is versed in the legal codes in his time, this paper intends to locate all the legal inaccuracies in The Merchant of Venice, a play known for its legal theme, and argues that these aberrations are consciously committed. Shakespeare deliberately creates a court scene that flouts important legal principles so as to reflect inequalities in the power relationships between various subcultures; law, the supposed embodiment of justice, is subtly tilted in favor of the more privileged groups and the more established discourses.

Vibrational Resonance in a Bistable System with Multiplicative and Additive Noise

Feng Guo,Xiao-Feng Cheng 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.6

The vibrational resonance (VR) phenomenon in a bias bistable system driven by a high-frequency (HF) signal and a low-frequency (LF) signal, as well as by multiplicative and additive white noises, is investigated. On the assumption that the frequency of the HF signal is much higher than that of the LF signal, using frequency-average on the HF signal, the Fokker-Planck equation for the averaged probability density is obtained. Under the adiabatic approximation, the expression of the signal-to-noise ratio (SNR) with respect to the LF signal is obtained. The SNR shows a VR behavior as a function of the amplitude and the frequency of the HF signal. In addition, the SNR varies non-monotonically with the intensities of the multiplicative and the additive noises, i.e., traditional stochastic resonance occurs. The influences of the system bias and the frequency of the LF signal on the SNR are also discussed.

Phenomenon of Entropic Stochastic Resonance with Asymmetric Dichotomous Noise and White Noise

Feng Guo,Shao-Fu Li,Xiao-Feng Cheng 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.3

The entropic stochastic resonance (ESR) in a confined system subject to asymmetric dichotomous noise, white noise, and a periodic square-wave signal is investigated. Under the adiabatic approximation condition, by use of the properties of the dichotomous noise, we obtain the expression of the output signal-to-noise ratio (SNR) based on two-state theory. The SNR is shown to be a nonmonotonic function of the strength and asymmetry of the dichotomous noise, the intensity of the white noise, and the amplitude of the square-wave signal. The SNR varies non-monotonically with increases in the parameters of the confined structure. The influence of the correlation rate of the dichotomous noise and the frequency of the external constant force on the SNR is also discussed.

Mechanical Property Test and Analytical Method for Reactive Powder Concrete Columns under Eccentric Compression

Cheng-hua Shi,Min Long,Cheng-yong Cao,Guangcheng Long,Ming-feng Lei 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.4

Reactive Powder Concrete (RPC) has ultra-high strength, toughness and durability. Review studies were focused on the mechanical properties of RPC material and RPC beam. In this paper, the bearing features of RPC columns under eccentric compression with different section dimensions, reinforcement ratios, and conditions of with and without steel fibres were determined through large eccentric compression test of 22 RPC columns. The distribution patterns of stresses over the section of the RPC columns under large eccentric compression were determined under cracking loads. A simple analytical method for the cracking loads was also established. Test results revealed that the thickness ratio of elastic tensile region and the whole tensile region can be 0.4 (with steel fibres) or 0.5 (without steel fibres) when calculating the cracking loads. The tensile stress on the RPC columns showed an isosceles triangle distribution in the tensile region. A simple analytical method for calculating the ultimate loads of RPC columns under large eccentric compression was set up. Test results revealed that the equivalence coefficient of the RPC column in tensile regions can be 0.6 (with steel fibres) or 0.4 (without steel fibres). The method deduced in this paper can be used to design the RPC column under large eccentric compression.

An Analysis of the Ground Deformation Caused by Shield Tunnel Construction Combining an Elastic Half-Space Model and Stochastic Medium Theory

Cheng-hua Shi,Cheng-yong Cao,Ming-feng Lei 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.5

The ground movement induced by the construction of shield tunnels affects the safety of nearby underground pipes and aboveground structures. Therefore, the reliable prediction of ground movement is important. In this paper, a model describing the interaction between soil and an EPB shield used in tunnels is presented, based on the classical elastic theory of Mindlin. In this model, the changing location of the working shield is considered. The equations describing the ground deformation around the tunnel caused by the additional force on the shield working surface and the frictional force between the outer surface of the shield and the surrounding soil are derived. The ground deformation caused by ground loss due to shield tunnel construction is derived using stochastic medium theory. Finally, this model is applied to two running tunnels, and the sensitivity of the ground deformation to the calculation parameters is discussed.

Molecular Cloning and Function Analysis of an Anthocyanidin Synthase Gene from Ginkgo biloba, and Its Expression in Abiotic Stress Responses

Feng Xu,Hua Cheng,Rong Cai,Lin Ling Li,Jie Chang,Jun Zhu,Feng Xia Zhang,Liu Ji Chen,Yan Wang,Shu Han Cheng,Shui Yuan Cheng 한국분자세포생물학회 2008 Molecules and cells Vol.26 No.6

Anthocyanidin synthase (ANS, leucoanthocyanidin oxygenase), a 2-oxoglutarate iron-dependent oxygenase, catalyzed the penultimate step in the biosynthesis of the anthocyanin class of flavonoids, from the colorless leucoanthocyanidins to the colored anthocyanidins. The full-length cDNA and genomic DNA sequences of ANS gene (designated as GbANS) were isolated from Ginkgo biloba for the first time. The full-length cDNA of GbANS contained a 1062-bp open reading frame (ORF) encoding a 354-amino-acid protein. The genomic DNA analysis showed that GbANS gene had three exons and two introns. The deduced GbANS protein showed high identities to other plant ANSs. The conserved amino acids (H-X-D) ligating ferrous iron and residues (R-X-S) participating in 2-oxoglutarate binding were found in GbANS at the similar positions like other ANSs. Southern blot analysis indicated that GbANS belonged to a multi-gene family. The expression analysis by real-time PCR showed that GbANS expressed in a tissue-specific manner in G. biloba. GbANS was also found to be up-regulated by all of the six tested abiotic stresses, UV-B, abscisic acid, sucrose, salicylic acid, cold and ethylene, consistent with the promoter region analysis of GbANS. The recombinant protein was successfully expressed in E. coli strain with pET-28a vector. The in vitro enzyme activity assay by HPLC indicated that recombinant GbANS protein could catalyze the formation the cyanidin from leucocyanidin and conversion of dihydroquercetin to quercetin, suggesting GbANS is a bifunctional enzyme within the anthocyanidin and flavonol biosynthetic pathway.

Influence of FeSe doping on superconducting properties of MgB2 by hybrid microwave method

Cheng Cheng,Zhenjie Feng,Qing Li,Xu Wang,Chuan Yu,Hao Chu,Ya Yang,Changqin Liu,Yiming Cao,Zhe Li,Jingzhe Chen,Chao Jing,Shixun Cao,Jincang Zhang 한국물리학회 2017 Current Applied Physics Vol.17 No.11

The effect of FeSe doping on the physical properties of MgB2 is studied. Bulk samples of the FeSe doped MgB2 with weight ratio x ðFeSe : MgB2Þ ¼ 0%; 3%; 7% and 10% were prepared by hybrid microwave method. It is proved that FeSe is not stable together with MgB2. Fe2þ enters into MgB2 lattice, some Mg2þ and Se2『 are combined into the new impurity compound MgSe. The superconducting transition temperature (Tc) slightly decreased with increasing doping content of FeSe from R-T and M-T curves, which results from the substitution of Mg2þ by Fe2þ in the MgB2 lattice. The Jc increase slightly with the FeSe doping content increasing from 3 wt % to 10 wt %, which results from the increasing MgSe impurity pinning centers.

Implications for new physics from ^B¯0→^π0^π0 and ^B¯0→^K¯0^K0

Cheng, Jian-Feng,Gao, Yuan-Ning,Huang, Chao-Shang,Wu, Xiao-Hong Elsevier 2006 Physics letters: B Vol.637 No.4

<P><B>Abstract</B></P><P>We have analyzed the <SUP>B¯0</SUP>→<SUP>π0</SUP><SUP>π0</SUP> puzzle in three kinds of models beyond the standard model (SM). It is shown that the minimal flavor violation (MFV) models, the minimal supersymmetric standard model (MSSM), and the two Higgs doublet models (2HDM) I and II cannot give an explanation of the <SUP>B¯0</SUP>→<SUP>π0</SUP><SUP>π0</SUP> puzzle within 1<I>σ</I> experimental bounds and the model III 2HDM can explain the puzzle without a conflict with other experimental measurements. If the constraint on <SUB>C8g</SUB> from b→sg is not imposed, for all kinds of insertions considered there are regions of parameter space, where the scalar quark mass is larger (much larger) than the gluino mass in the case of <I>LR</I> or <I>RL</I> (<I>LL</I> or <I>RR</I>), in which the puzzle can be resolved within 1<I>σ</I> experimental bounds.</P>