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SYMMETRICAL SISF IN DEFORMED Ni_3Al AND ITS FORMATION MECHANISM

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Acta Metallurgica Sinica(English Letters) 1992年第2期5卷 76-81页

作者： yan Wen xi′an Institute of Technology,xi′an,China xi'an Inst of Technology Xi'an China

The symmetrical superlattice intrinsic stacking faults(SISFs)formed on {111} planes are the predominant crystal defects in polycrystalline Ni_3AI after slight deformation at room temper- *** formation of this kind of SISF is resulted from the dipoles which are distributed on the neighboring {111} planes after reorientation,dissociation and annihilation under applied stress.

关键词： deformed Ni_3Al symmetrical stacking fault formation mechanism

NUMERICAL SIMULATIONS OF NONLINEAR WAVE TRANSFORMATION AROUND WAVE-PERMEABLE STRUCTURE

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Journal of Hydrodynamics 2005年第6期17卷 699-703页

作者： Li xi yan Yi-xin Department of Ocean Engineering Hohai University Nanjing 210098 China

The problem of wave partial/full reflection and transmission by wave-permeable structure is approached by solving the shape-related function with focus on the understanding of wave attenuation. 2D depth averaged Boussinesq type wave equations are given with new damping item in simulating the nonlinear wave transmission through wave-permeable structure. 1D wave equation is examined to give the analytical expression of the absorbing coefficient, and is compared with laboratory data in flume to calibrate the coefficients, and the expression is applied directly in modified Boussinesq type equations. Compared with wave basin data for various incident wave conditions, the accurate predictions of combined diffraction refraction effects in simulating nonlinear wave going through wave-permeable breakwater in the engineering application can be obtained. It shows that wave-permeable breakwaters with proper absorbing effects can be used as an effective alternative to massive gravity breakwaters in reduction of wave transmission in shallow water.

关键词： Boussinesq equations wav-absorbing coeffieient wave permeable breakwaters

Modified bottleneck-based heuristic for large-scale job-shop scheduling problems with a single bottleneck

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Journal of Systems Engineering and Electronics 2007年第3期18卷 556-565页

作者： Zuo yan Gu Hanyu xi Yugeng Inst. of Automation Shanghai Jiaotong Univ. Shanghai 200240 P. R. China

A modified bottleneck-based （MB） heuristic for large-scale job-shop scheduling problems with a welldefined bottleneck is suggested, which is simpler but more tailored than the shifting bottleneck （SB） procedure. In this algorithm, the bottleneck is first scheduled optimally while the non-bottleneck machines are subordinated around the solutions of the bottleneck schedule by some effective dispatching rules. Computational results indicate that the MB heuristic can achieve a better tradeoff between solution quality and computational time compared to SB procedure for medium-size problems. Furthermore, it can obtain a good solution in a short time for large-scale jobshop scheduling problems.

关键词： job shop scheduling problem bottleneck shifting bottleneck procedure.

Zr-doped titanium lithium ion sieve and EP-granulated composite:Superb adsorption and recycling performance

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Particuology 2022年第10期20卷 100-110页

作者： Suyu Zhou xiaojing Guo xi yan yan Chen Wanzhong Lang The Education Ministry Key Laboratory of Resource Chemistry Shanghai Key Laboratory of Rare Earth Functional MaterialsDepartment of Chemistry and Chemical EngineeringShanghai Normal UniversityShanghai 200234China

Lithium ion sieve(LIS)has attracted great attention due to its high adsorption selectivity towards Li+.Herein,a new type of Zr-doped Ti-LIS(HZrTO)was synthesized by a simple calcination *** adsorption capacity increased from 56.3 mgg-1(before doping)to 93.2 mgg-1 after doping in LiOH solution(lithium 1.8gL-1).The adsorption isotherm and adsorption kinetics of HZrTO accord with the Langmuir isotherm and the pseudo-second-order kinetic equation,*** experiments showed that HZrTO has good stability and *** addition,HZrTO was granulated via epoxy resin(E-12),and the obtained granular adsorbent showed good adsorption capacity,excellent stability and high selectivity towards Li+.

关键词： Lithium ion sieve Lithium titanium oxide Zr-doped Granulation

Singular Value Inequalities of Matrix Sum in Log-ma jorizations

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Acta Mathematica Sinica,English Series 2023年第2期39卷 375-386页

作者： Bo yan xi Fu Zhen ZHANG College of Mathematics Inner Mongolia Minzu UniversityTongliao028043China Department of Mathematics Nova Southeastern University3301 College Ave.Fort LauderdaleFL33314USA

We show some upper bounds for the product of arbitrarily selected singular values of the sum of two *** results are additional to our previous work on the lower bound eigenvalue inequalities of the sum of two positive semidefinite ***,we state explicitly Hoffman’s minimax theorem with a proof,and as applications of our main results,we revisit and give estimates for related determinant inequalities of Hua type.

关键词： Eigenvalue Hoffman minimax theorem Hua determinant inequality log-majorization majorization Minkowski determinant inequality singular value Wielandt minimax theorem

Optimal slag content for geopolymer composites under freeze-thaw cycles with different freezing temperatures

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第4期24卷 366-376页

作者： Lifeng FAN Weiliang ZHONG Guang WANG yan xi Faculty of Architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing 100124China

Improving the freeze-thaw resistance of geopolymers is of great significance to ensure their durability in cold regions. This study presents an experimental investigation of optimal slag content for geopolymer composites under freeze-thaw cycles with different freezing temperatures. Firstly, five kinds of geopolymer composites with 10.0%, 20.0%, 30.0%, 40.0%,and 50.0% slag contents and 1.0% fiber content were prepared. Freeze-thaw cycle tests at-1.0 ℃,-20.0 ℃, and-40.0 ℃ were carried out for these geopolymer composites and their physical and mechanical properties after the freeze-thaw cycle were tested. The results show that the porosity of the geopolymer composites decreases as the slag content increases. Their mass loss ratio and strength loss ratio increase gradually as the freezing temperature decreases. The mass loss ratio and strength loss ratio of geopolymer composites after freeze-thaw cycles all decrease as the slag content increases. Considering the physical and mechanical properties of geopolymers after freeze-thaw cycles, the optimal slag contents are 40.0% and 50.0%.

关键词： Geopolymer composites Freeze-thaw cycle Freezing temperature Slag content

Investigation of three different cooling treatments on dynamic mechanical properties and fragmentation characteristics of granite subjected to thermal cycling

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Underground Space 2022年第5期7卷 847-861页

作者： Lifeng Fan Han Li yan xi Beijing University of Technology Beijing 100124China

Underground thermal engineering such as geothermal exploitation usually involves the response of impact loads due to the drilling operation and blasting *** study investigated the dynamic mechanical properties and fragmentation characteristics of granite subjected to thermal cycling under natural cooling,water cooling,and liquid nitrogen ***,split Hopkinson pressure bar tests were performed on granite under three different cooling methods to study the dynamic mechanical parameters with thermal ***,the damage factors were calculated to evaluate the damage on granite and the relationship between damage and ***,the granite fragments after impact were sieved,and the fractal dimension and average fragment size were introduced to analyze the fragmentation *** results demonstrate that the degradation of dynamic mechanical properties mainly occurs in the first four thermal cycles;with the increase of damage factor,the stress decreases linearly under the three cooling methods,and the damage caused by liquid nitrogen cooling to granite is the most significant,followed by water *** of granite change from axial splitting failure to a more complex composite failure *** addition,with the decrease of the average fragment size,the fractal dimension of the granite gradually increases,resulting in the higher fragmentation degree and the better uniformity of fragmentation.

关键词： Split Hopkinson pressure bar Dynamic mechanical properties Fragmentation characteristics Cooling treatment

MODIFIED BOTTLENECK-BASED PROCEDURE FOR LARGE-SCALE FLOW-SHOP SCHEDULING PROBLEMS WITH BOTTLENECK

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Chinese Journal of Mechanical Engineering 2006年第3期19卷 356-361页

作者： ZUO yan GU Hanyu xi Yugeng Institute of Automation Shanghai Jiaotong University Shanghai 200240 China

A new bottleneck-based heuristic for large-scale flow-shop scheduling problems with a bottleneck is proposed, which is simpler but more tailored than the shifting bottleneck （SB） procedure. In this algorithm, a schedule for the bottleneck machine is first constructed optimally and then the non-bottleneck machines are scheduled around the bottleneck schedule by some effective dispatching rules. Computational results show that the modified bottleneck-based procedure can achieve a tradeoff between solution quality and computational time comparing with SB procedure for medium-size problems. Furthermore it can obtain a good solution in quite short time for large-scale scheduling problems.

关键词： Flow-shop scheduling problem Heuristic Bottleneck machine

THE SOLVABILITY CONDITIONS FOR THE INVERSE PROBLEM OF BISYMMETRIC NONNEGATIVE DEFINITE MATRICES

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Journal of Computational Mathematics 2000年第6期18卷 597-608页

作者： Dong-xiu xie Lei Zhang xi-yan Hu Department of Applied Mathematics Dalian University of TechnologyDalian 116023China Department of Applied Mathematics Hunan UniversityChangsha 410082China Hunan Computing Center Changsha 410012China

A = (a[sub ij]) ∈ R[sup n×n] is termed bisymmetric matrix if a[sub ij] = a[sub ji] = a[sup n ? j + 1, n ? i + 1], i, j = 1, 2 ··· n. We denote the set of all n x n bisymmetric matrices by BSR[sup n x n]. This paper is mainly concerned with solving the following two problems: Problem I. Given X, B ∈ R[sup n×m], find A ∈ P[sub n] such that AX = B, where P[sub n] = {A ∈ BSR[sup n×n]| x[sup T] Ax ≥ 0, ?x ∈ R[sup n]}. Problem II. Given A[sup *] ∈ R[sup n×n], find ? ∈ S[sub E] such that ||A[sup *] - ?||[sub F] = ... ||A[sup *] - A||[sub F] where || · ||[sub F] is Frobenius norm, and S[sub E] denotes the solution set of problem I. The necessary and sufficient conditions for the solvability of problem I have been studied. The general form of S[sub E] has been given. For problem II the expression of the solution has been provided. [ABSTRACT FROM AUTHOR]

关键词： Frobenius norm bisymmetric matrix the optimal solution