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.

K-doping effect of the superconductivity in K2xFeTe1-xSx (0.07 ≤ x ≤ 0.3)

Cheng Cheng,Zhenjie Feng,Qing Li,Tao Li,Qiang Hou,Fei Chen,Zhongmin Ou,Jun-Yi Ge,Shixun Cao,Jincang Zhang 한국물리학회 2019 Current Applied Physics Vol.19 No.4

Bulk samples of K doping K2xFeTe1-xSx with x=0.07, 0.1, 0.2, 0.3 are successfully prepared by using easy-to-use stable compound K2S as the reactant. The lattice constant calculated from X-ray diffraction patterns indicate that K ions enter the Fe-Te-S layers. K doping is beneficial enhance the superconductivity transition temperature from the R-T curves. The apparent diamagnetic signal is observed in M-T curves when the content of K is smaller than 0.1. However, differential curves (dM/dT) in K-rich samples appear sharp slope mutations, which means that the Meissner effect signal is covered by the increased excess ferromagnetic ions. The number of excess Fe magnetic ions is proportional to K content, which may play an important role in determining the superconductivity.

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.

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.

Tetrazolium Violet Induces Apoptosis via Caspases-8, -9 Activation and Fas/FasL Up-regulation in Rat C6 Glioma Cells

Cheng-fa Cai,Yun-feng Zhao,Lei Feng,Lei Wang,Qing-zhong Kong 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.4

Tetrazolium violet (TV), a tetrazolium salt, was synthesized as a novel and potent anticancer agent with a broad spectrum of anticancer activity against many cancer cells. A previous study showed that tetrazolium violet inhibited cell growth, and induced cell cycle arrest and apoptosis in C6 Rat glioma cells. It also showed that treatment of cells with TV for 24 h resulted in a dramatic up-regulation of p53, and an increase in the activity of caspase-3, accompanied with a significant increase of Bax/Bcl-2 ratio. In this study, we further investigated which Fas/FasL and caspase were activated by TV during the apoptosis. Annexin-V-propidium iodide (PI) binding assay and nucleosome ELISA assay further indicated that TV induced a typical apoptosis, in a time-dose-dependent manner. The data showed that the activity of Fas/FasL and caspase-8 and -9 were significantly enhanced by the compound, which suggested that TV might be used as a Fas/FasL and caspases promoter to initiate brain cancer cell apoptosis.

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>