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A Note on Skew Cyclic Codes over a Class of Rings

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Algebra Colloquium 2020年第4期27卷 703-712页

作者： Hai q.Dinh Bac t.Nguyen Songsak Sriboonchitta Division of Computational Mathematics and Engineering Institute for Computational Science Ton Due Thang University Ho Chi Minh CityVietnam Faculty of Mathematics and Statistics Ton Due Thang University Ho Chi Minh CityVietnam Department of Basic Sciences University of Economics and Business Administration Thai Nguyen UniversityThai Nguyen ProvinceVietnam Centre of Excellence in Econometrics Faculty of Economics Chiang Mai UniversityChiang Mai 52000Thailand

We study skew cyclic codes over a class of rings R=F0■F1■⋯■Ft−1,where each Fi(i=0,…,t−1)is a finite *** prove that a skew cyclic code of arbitrary length over R is equivalent to either a usual cyclic code or a quasi-cyclic code over ***,we discuss possible extension of our results in the more general setting ofδR-dual skew constacyclic codes over R,whereδR is an automorphism of R.

关键词： skew constacyclic codes dual codes repeated-root codes quasi-cyclic codes local rings

Vibration characteristics of piezoelectric functionally graded carbon nanotube-reinforced composite doubly-curved shells

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Applied Mathematics and Mechanics(English Edition) 2021年第6期42卷 819-840页

作者： V.V.tHAM H.q.tRANt t.M.tU National Univensity of Ciwil Engineering Giai Phong Road 55Hai Ba Trung DistrictHanoi 100000 Vietnam

this paper presents an analytical solution for the free vibration behavior of functionally graded carbon nanotube-reinforced composite(Fg-CNtRC) doubly curved shallow shells with integrated piezoelectric layers. Here, the linear distribution of electric potential across the thickness of the piezoelectric layer and five different types of carbon nanotube(CNt) distributions through the thickness direction are considered. Based on the four-variable shear deformation refined shell theory, governing equations are obtained by applying Hamilton's principle. Navier's solution for the shell panels with the simply supported boundary condition at all four edges is derived. Several numerical examples validate the accuracy of the presented solution. New parametric studies regarding the effects of different material properties, shell geometric parameters, and electrical boundary conditions on the free vibration responses of the hybrid panels are investigated and discussed in detail.

关键词： free vibration four-variable shear deformation refined theory functionally graded carbon nanotube-reinforced composite(Fg-CNtRC) piezoelectric material

Reversal of radial glow distribution in helicon plasma induced by reversed magnetic field

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Plasma Science and technology 2017年第2期19卷 15-19页

作者： Y WANg g ZHAo C NIU Z W LIU J t oUYANg q CHEN School of physics Beijing institute of technology Beijing 100081 People＇s Republic of China Laboratory of Plasma physics ＆ Materials Beijing Institute of Graphic Communication Beijing 102600 People＇s Republic of China

In this work, the reversal of radial glow distribution induced by reversed magnetic field is reported. Based on the Boswell antenna which is symmetric and insensitive to the magnetic field direction, it seems such a phenomenon in theory appears impossible. However, according to the diagnostic of the helicon waves by magnetic probe, it is found that the direction of magnetic field significantly affects the propagation characteristic of helicon waves, i.e., the interchange of the helicon waves at the upper and the lower half of tube was caused by reversing the direction of magnetic field. It is suggested that the variation of helicon wave against the direction of magnetic field causes the reversed radial glow distribution. the appearance of the traveling wave does not only improve the discharge strength, but also determines the transition of the discharge mode.

关键词： helicon plasma reversal of radial glow distribution the direction of magnetic field

Preparation　of　YSZ　Microporous　Membranes　on　Porous　α-Alumina　with　Metal　chlorides　as　Precursor

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Chemical Research in Chinese Universities 1997年第3期13卷 268-275页

作者： Peng, DK Liu, t Yang, ph Xia, CR Meng, gY UNIV SCI & tECHNoL CHINA DEPT MAT SCI & ENGNHEFEI 230026PEOPLES R CHINA

ＰｒｅｐａｒａｔｉｏｎｏｆＹＳＺＭｉｃｒｏｐｏｒｏｕｓＭｅｍｂｒａｎｅｓｏｎＰｏｒｏｕｓα－ＡｌｕｍｉｎａｗｉｔｈＭｅｔａｌｃｈｌｏｒｉｄｅｓａｓＰｒｅｃｕｒｓｏｒＰＥＮＧＤｉｎｇ－ｋｕｎ，ＬＩＵＴａｏ，ＹＡＮＧＰｉ... 详细信息

ＰｒｅｐａｒａｔｉｏｎｏｆＹＳＺＭｉｃｒｏｐｏｒｏｕｓＭｅｍｂｒａｎｅｓｏｎＰｏｒｏｕｓα－ＡｌｕｍｉｎａｗｉｔｈＭｅｔａｌｃｈｌｏｒｉｄｅｓａｓＰｒｅｃｕｒｓｏｒＰＥＮＧＤｉｎｇ－ｋｕｎ，ＬＩＵＴａｏ，ＹＡＮＧＰｉｎｇ－ｈｕａ，ＸＩＡＣｈａｎｇ－ｒ...

关键词： YSZ Preparation Alumina Membranes Metal Microporous Porous Precursor

A deep feed-forward neural network for damage detection in functionally graded carbon nanotube-reinforced composite plates using modal kinetic energy

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Frontiers of Structural and Civil Engineering 2021年第6期15卷 1453-1479页

作者： Huy q.LE tam t.tRUoNg D.DINH-CoNg t.NgUYEN-tHoI Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh City 700000Vietnam Faculty of Civil Engineering Ho Chi Minh City University of TransportHo Chi Minh City 700000Vietnam Division of Construction Computation Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh City 700000Vietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh City 700000Vietnam

this paper proposes a new Deep Feed-forward Neural Network(DFNN)approach for damage detection in functionally graded carbon nanotube-reinforced composite(Fg-CNtRC)*** the proposed approach,the DFNN model is developed based on a data set containing 20000 samples of damage scenarios,obtained via finite element(FE)simulation,of the Fg-CNtRC *** elemental modal kinetic energy(MKE)values,calculated from natural frequencies and translational nodal displacements of the structures,are utilized as input of the DFNN model while the damage locations and corresponding severities are considered as *** state-of-the art Exponential Linear Units(ELU)activation function and the Adamax algorithm are employed to train the DFNN ***,in order to enhance the performance of the DFNN model,the mini-batch and early-stopping techniques are applied to the training process.A trial-and-error procedure is implemented to determine suitable parameters of the network such as the number of hidden layers and the number of neurons in each *** accuracy and capability of the proposed DFNN model are illustrated through two distinct configurations of the CNt-fibers constituting the Fg-CNtRC plates including uniform distribution(UD)and functionally graded-V distribution(Fg-VD).Furthermore,the performance and stability of the DFNN model with the consideration of noise effects on the input data are also *** results indicate that the proposed DFNN model is able to give sufficiently accurate damage detection outcomes for the Fg-CNtRC plates for both cases of noise-free and noise-influenced data.

关键词： damage detection deep feed-forward neural networks functionally graded carbon nanotube-reinforced composite plates modal kinetic energy

Rational design of chemically complex metallic glasses by hybrid modeling guided machine learning

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npj Computational Materials 2021年第1期7卷 1242-1251页

作者： Z.q.Zhou q.F.He X.D.Liu q.Wang J.H.Luan C.t.Liu Y.Yang Department of Mechanical Engineering College of EngineeringCity University of Hong KongKowloonHong KongChina College of Mechatronics and Control Engineering Shenzhen UniversityShenzhenChina Laboratory for Structures Institute of Materials ScienceShanghai UniversityShanghaiChina Department of Materials Science and Engineering College of EngineeringCity University of Hong KongKowloonHong KongChina Department of Advanced Design and System Engineering College of EngineeringCity University of Hong KongChina

the compositional design of metallic glasses(Mgs)is a long-standing issue in materials science and ***,traditional experimental approaches based on empirical rules are time consuming with a low *** this work,we successfully developed a hybrid machine learning(ML)model to address this fundamental issue based on a database containing~5000 different compositions of metallic glasses(either bulk or ribbon)reported since *** the prior works relying on empirical parameters for featurization of data,we designed modeling guided data descriptors in line with the recent theoretical models on amorphization in chemically complex alloys for the development of the hybrid classification-regression ML *** hybrid ML modeling was validated both numerically and *** importantly,it enabled the discovery of Mgs(either bulk or ribbon)through the ML-aided deep search of a multitude of quaternary to scenery alloy *** computational framework herein established is expected to accelerate the design of Mg compositions and expand their applications by probing the complex and multi-dimensional compositional space that has never been explored before.

关键词： alloy glasses metallic

INFLUENCE oF SILICoN IN StEELS oN gALVANIZED CoAtINgS

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Acta Metallurgica Sinica(English Letters) 2006年第2期19卷 85-90页

作者： C.S. Che J.t. Lu g. Kong q.Y. Xu J.H. Chen College of Materials Science and Engineering South China University of Technology Guangzhou 510640 China

After steel sheets （0.37wt%Si） pre-electroplated with a thin layer of pure Fe were immersed in molten zinc for various time, the change in the microstructure of the galvanized coating on the steel and the change of α-Fe/Г interface were studied. the EDS （energy dispersive sepectroscopy） resuits show that excessive silicon accumulates on the surface of the steel substrate due to the low solubility of silicon in the Г layer after the Fe layer is depleted by the increasing growth of the compound layers. With the movement of α-Fe/Г interface towards the substrate by the Fe/Zn reaction, silicon-rich α-Fe peels off from the substrate and breaks into particles. the particles, much like an inert marker in a Kirkendall effect experiment, move towards the δ layer through the Г layer because silicon-rich α-Fe can not be adsorbed in the Г layer. on reaching the 8/F interface, the particles quickly dissolve in the δ layer, and accelerate its growth, resulting in the gradual disappearance of the Г layer. At the same time, the normal coating is quickly changed into coatings typical of reactive steels as silicon dissolved in the δ layer soon diffuses toward the ζ layer. A similar process may happen in the initial stage of galvanizing reactive steels on a small scale, although it is hard to be observed.

关键词： Zn coating intermetallics steel electrodeposition

on a Class of Constacyclic Codes of Length 4p^8 over Fpm[u]/〈 u^a 〉

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Algebra Colloquium 2019年第2期26卷 181-194页

作者： Hai q. Dinh Bac t. Nguyen Songsak Sriboonchitta Division of Computational Mathematics and Engineering Institute for Computational Science Ton Due Thang University Ho Chi Minh City Vietnam Faculty of Mathematics and Statistics Ton Due Thang University Ho Chi Minh City Vietnam Nguyen tat thanh University Ho Chi Minh City Vietnam Department of Basic Sciences University of Economics and Business Administration Thai Nguyen University Thai Nguyen Province Vietnam Faculty of Economics Chiang Mai University Chiang Mai 52000 Thailand

For any odd prime p such that p^m ≡ 3 (mod 4), consider all units Λ of the finite commutative chain ring Ra=Fpm[u]/〈u^a〉=Fp^m+uFp^m+…+u^a1Fp^m that have the form Λ=Λ0 + uΛ1 ++ u^a1 Λa1, where Λ0,Λ1,…,Λa1 p^m,Λ0 ≠ 0,Λ1 ≠ 0. the class of Λ-constacyclic codes of length 4p^s over a is investigated. If the unit Λ is a square, each Λ-constacyclic code of length 4p^s is expressed as a direct sum of a λ-constacyclic code and a λ-constacyclic code of length 2p^s. In the main case that the unit Λ is not a square, we prove that the polynomial x^4 λ0 can be decomposed as a product of two quadratic irreducible and monic coprime factors, where λ^p^s0=Λ0. From this, the ambient ring Ra[x]/is proven to be a principal ideal ring, whose maximal ideals are and , where λ0 =4η^4. We also give the unique self-dual type 1 Λ-constacyclic codes of length 4p^s over a. Furthermore, conditions for a type 1 Λ-constacyclic code to be self-orthogonal and dual-containing are provided.

关键词： constacyclic codes dual codes chain rings

Forced Convective Heat transfer and Pressure Drop of Air Flowing in a Rectangle Duct with Cross-Ribs on the opposite Walls

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Journal of thermal Science 2002年第3期11卷 259-270页

作者： B.Deng t.t.Wong W.q.tao School of Power and Energy Xi’an Jiaotong University Xi’an China Department of Mechanical Engineering The Hong Kong Polytechnic University Hong Kong

Experiments were conducted to investigate the forced convective heat transfer and flow friction of turbulent airflow in a rectangular duct with cross-ribs attached at the two principal walls in the Reynolds number range from 5000 to 40000. the effect of the rib cross angle (45° 60° 75° and the height (4 mm, 5 mm) of the cross-ribs on the forced convection and flow friction were tested. Non-dimensional correlations for the duct average Nusselt number and friction factor of cross-ribs duct were developed from the test data. Experiments were also conducted for the corresponding parallel ribs to compare their relative performance. the experimental results show that both of the convective heat transfer coefficient and friction factor were increased with cross-ribs, with 45°cross-ribs being the best. Compared with parallel ribs normal to the flow direction under identical flow rate and identical pumping power constraints, the cross-ribs can enhance heat transfer in the lower Reynolds number region, while

关键词： cross-ribs forced convection heat transfer enhancement.