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.

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.

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.

Deformation Characteristics and Countermeasures of shallow and Large-span Tunnel Under-crossing the Existing Highway in Soft Soil: a Case Study

Cheng-yong Cao,Cheng-hua Shi,Ming-feng Lei,Li-min Peng,Ruxue Bai 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

Hongmian Road goes under Jihe highway by the way of tunnel in Shenzhen City, Guangdong Province, China. The tunnel hassome special characteristics such as shallow depth, large span, soft soil, busy traffic, and long distance under-crossing the operatinghighway, thus there is great difficulty and risk during its construction. A series of in-situ tests were conducted to reveal deformationcharacteristics during tunneling beneath the existing highway by the double-side-drift method (DSDM). The results show that initialconstruction method and measures can't meet the safety requirement of tunnel construction, and the level of risk is extremely high, sothe construction method need to be timely adjusted. By comprehensive analysis, the double-side-drift optimum method (DSDOM) isput forward, on the basis of which a series of optimum measures also have been put forward, such as reasonable constructionmethods, the suitable length of bench and excavation, soil reinforcement measures on tunnel face, optimizing construction process,closing primary support in time and speeding up the construction of secondary lining. Then the feasibility of this optimizedconstruction method and measures are verified by the numerical simulations. Finally, from feedbacks of monitoring results, theoptimum method and measures have been proved to be reasonable and feasible, and they can guarantee a successful pass beneath theoperating highway.

Simultaneous identification of bearing dynamic coefficients in a water-gas lubricated hydrostatic spindle with a big thrust disc

Feng Cheng,Wei-Xi Ji 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9

A water-gas lubricated hydrostatic spindle system with big thrust disc, supported by a water-lubricated journal bearing and a gaslubricated thrust bearing, is developed to improve spindle stiffness and to reduce friction power of spindle. A new identification algorithm is derivated to identify simultaneously the eighteen dynamic coefficients of the coupled journal and thrust bearings. A comparison with the available experimental results reveals that the bearing coefficients is well estimated by the present theoretical model. The results also indicate that, the estimated bearing parameters by regularization solution are in good agreement with the assumed values; while it has opposite effect by directed solution for discrete ill-posed problems. It is concluded that, the identification accuracy of bearing parameters is govern by the measured errors; contrast to unbalance mass error and unbalance phase error, the displacement error leads the maximal percentage deviations of estimated coefficients.

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>

An improved time-domain approach for the spectra-compatible seismic motion generation considering intrinsic non-stationary features

Cheng Feng,Li Jianbo,Ding Zhixin,Lin Gao 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.3

The dynamic structural responses are sensitive to the time-frequency content of seismic waves, and seismic input motions in time-history analysis are usually required to be compatible with design response spectra according to nuclear codes. In order to generate spectra-compatible input motions while maintaining the intrinsic non-stationarity of seismic waves, an improved time-domain approach is proposed in this paper. To maintain the nonstationary characteristics of the given seismic waves, a new time-frequency envelope function is constructed using the Hilbert amplitude spectrum. Based on the intrinsic mode functions (IMFs) obtained from given seismic waves through variational mode decomposition, a new corrective time history is constructed to locally modify the given seismic waves. The proposed corrective time history and time-frequency envelope function are unique for each earthquake records as they are extracted from the given seismic waves. In addition, a dimension reduction iterative technique is presented herein to simultaneously superimpose corrective time histories of all the damping ratios at a specific frequency in the time domain according to optimal weights, which are found by the genetic algorithm (GA). Examples are presented to show the capability of the proposed approach in generating spectra-compatible time histories, especially in maintaining the nonstationary characteristics of seismic records. And numerical results reveal that the modified time histories generated by the proposed method can obtain similar dynamic behaviors of AP1000 nuclear power plant with the natural seismic records. Thus, the proposed method can be efficiently used in the design practices

Topology Optimization Method of Lattice Structures Based on a Genetic Algorithm

Feng Ruo-qiang,Liu Feng-cheng,Xu Wei-jia,Liu Yang 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

A two-stage topology optimization method of lattice structures based on a genetic algorithm is proposed. The first stage is the form-finding analysis of lattice structures, and the optimal initial shape was achieved with the numerical inverse hanging method. The second stage is the topology optimization of single-layer lattice structures, which can be realized by changing the mesh size and the tube configurations to minimize the total weight of steel tubes subject to the design requirements. The mesh configuration optimization is realized through the adjustment of the nodal horizontal co-ordinates and the removal of tubes with lower stress. The maximum displacement of the structure, the maximum stress of the circular steel tubes, and the nonlinear buckling load are the state variables, and a genetic algorithm (GA) is the optimization algorithm. Different stress-limiting values used to delete the tubes were discussed. The numerical examples show that the two-stage topology optimization method for lattice structures proposed in this paper is correct and efficient. Furthermore, the forms of the optimized structure are rich, and the structure is lightweight and efficient.

“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.

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.