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Collapse assessment of steel moment frames using endurance time method

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earthquake engineering and engineering Vibration 2015年第2期14卷 347-360页

作者： e.Rahimi H.e.estekanchi Department of Civil engineering Sharif University of Technology (SUT)

In endurance time(eT) method structures are subjected to a set of predesigned intensifying excitations. These excitations are produced in a way that their response spectrum, while complying with a specifi ed spectrum, intensifi es with time so they can be used approximately to simulate the average effects of several ground motions scaled to different intensities. In this paper applicability of the eT method for evaluating collapse potential of buildings is investigated. A set of four steel moment frames is used for collapse assessment. The process of using eT method in collapse evaluation is explained and the results are compared with incremental dynamic analysis(IDA) results. It is shown that although the computational effort using the eT method is much less than the IDA analysis, the results of both methods are consistent. Finally collapse fragility curves using eT and IDA methods are produced and it is shown that the probabilities of collapse in different hazard levels are also consistent.

关键词： endurance time method collapse analysis incrementa

温经汤加减联合隔姜灸治疗寒凝血瘀型痛经的临床效果

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临床医学研究与实践 2025年第6期10卷 122-125页

作者：娄景娥新密市中医院郑州新密452370

目的分析温经汤加减联合隔姜灸治疗寒凝血瘀型痛经的临床效果。方法选择2023年1月至5月我院收治的40例寒凝血瘀型痛经患者作为研究对象,以治疗方案差异将其分为对照组和研究组,各20例。对照组给予布洛芬缓释胶囊口服治疗,研究组接受... 详细信息

目的分析温经汤加减联合隔姜灸治疗寒凝血瘀型痛经的临床效果。方法选择2023年1月至5月我院收治的40例寒凝血瘀型痛经患者作为研究对象,以治疗方案差异将其分为对照组和研究组,各20例。对照组给予布洛芬缓释胶囊口服治疗,研究组接受温经汤加减联合隔姜灸治疗。比较两组的治疗效果。结果研究组的治疗总有效率高于对照组(P0.05);治疗后,研究组的VAS评分、中医证候积分低于对照组,疼痛持续时间短于对照组(P0.05);治疗后,研究组的PT短于对照组,INR、PI及RI低于对照组,APTT长于对照组(P<0.05)。结论温经汤加减联合隔姜灸治疗寒凝血瘀型痛经患者的效果显著,有助于改善疼痛症状,调节血流动力学平衡,值得临床应用。

关键词：温经汤加减隔姜灸寒凝血瘀型痛经

INVeRSe PROBLeMS FOR A GeNeRAL MULTI-CONNeCTeD BOUNDeD DRUM WITH APPLICATIONS IN PHYSICS

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Acta Mathematica Scientia 2003年第1期23卷 104-116页

作者： e.M.e.Zayed Mathematics Department Faculty of Science Zagazig University Zagazig Egypt

This paper studies the influence of a finite container on an ideal *** trace of the heat kernel (t) =exp, where are the eigenvalues of the negative Laplacian -in Rn(n = 2 or 3), is studied for a general multi-connected bounded drum ft which is surrounded by simply connected bounded domains Ωi with smooth boundaries Ωi(i = 1,… ,m) where the Dirichlet, Neumann and Robin boundary conditions on Ωi(i = 1,…,m) are considered. Some geometrical properties of Ω are determined. The thermodynamic quantities for an ideal gas enclosed in Ω are examined by using the asymptotic expansions of (t) for short-time t. It is shown that the ideal gas can not feel the shape of its container Ω, although it can feel some geometrical properties of it.

关键词： Inverse problem heat kernel eigenvalues an ideal gas multi-connected bounded domain

The 3D Inverse Problem of the Wave equation for a General Multi-connected Vibrating Membrane with a Finite Number of Piecewise Smooth Boundary Conditions

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Acta Mathematica Sinica,english Series 2005年第4期21卷 733-752页

作者： e.M.e.ZAYeD Mathematics Department Faculty of ScienceZagazig UniversityZagazig.Egypt

The trace of the wave kernel μ（t） =∑ω=1^∞ exp（-iteω^1/2）, where {eω}ω^∞=1 are the eigenvalues of the negative Laplacian -△↓2 = -∑k^3=1 （δ/δxk）^2 in the （x^1, x^2, x^3）-space, is studied for a variety of bounded domains, where -∞ 〈 t 〈 ∞ and i= √-1. The dependence of μ （t） on the connectivity of bounded domains and the Dirichlet, Neumann and Robin boundary conditions are analyzed. Particular attention is given for a multi-connected vibrating membrane Ω in Ra surrounded by simply connected bounded domains Ω j with smooth bounding surfaces S j （j = 1,……, n）, where a finite number of piecewise smooth Dirichlet, Neumann and Robin boundary conditions on the piecewise smooth components Si^＊（i = 1 ＋ kj-1,……, kj） of the bounding surfaces S j are considered, such that S j = Ui-1＋kj-1^kj Si^＊, where k0=0. The basic problem is to extract information on the geometry Ω by using the wave equation approach from a complete knowledge of its eigenvalues. Some geometrical quantities of Ω （e.g. the volume, the surface area, the mean curvuture and the Gaussian curvature） are determined from the asymptotic expansion ofexpansion of μ（t） for small │t│.

关键词： Inverse problem Wave kernal eigenvalues Greens function Multi-connected vibrating membrane Negative Laplacian Heat kernel

The Asymptotics of the Two-Dimensional Wave equation for a General Multi-Connected Vibrating Membrane with Piecewise Smooth Robin Boundary Conditions

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Acta Mathematica Sinica,english Series 2004年第2期20卷 209-222页

作者： e.M.e.ZAYeD Department of Mathematics Faculty of ScienceZagazig UniversityZagazigEgypt

The asymptotic expansion for small |t| of the trace of the wave kernel , where and are the eigenvalues of the negative Laplacian in the (x 2,x 2)-plane, is studied for a multi-connected vibrating membrane ? in R 2 surrounded by simply connected bounded domains ? j with smooth boundaries ?? j (j = 1, ..., n), where a finite number of piecewise smooth Robin boundary conditions on the piecewise smooth components Γ i (i = 1+k j?1, ..., k j ) of the boundaries ?? j are considered, such that and k 0 = 0. The basic problem is to extract information on the geometry of ? using the wave equation approach. Some geometric quantities of ? (e. g. the area of ?, the total lengths of its boundary, the curvature of its boundary, the number of the holes of ?, etc.) are determined from the asymptotic expansion of the trace of the wave kernel for small |t|.

关键词： Inverse problem Wave kernel eigenvalues Robin boundary conditions Vibrating membrane Hearing the shape of a drum

Asymptotic expansions of the Heat Kernel of the Laplacian for General Annular Bounded Domains with Robin Boundary Conditions：Further Results

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Acta Mathematica Sinica,english Series 2003年第4期19卷 679-694页

作者： e.M.e.ZAYeD DepartmentofMathematics FacultyofScienceZagazigUniversityZagazigEgypt

The asymptotic expansions of the trace of the heat kernel Θ(t) = Σ_(v =1)~∞exp(-tλ_v) for small positive t, where {λ_v} are the eigenvalues of the negative Laplacian-△_n = -Σ_(i = 1)~n(partial deriv/(partial deriv)x^i)~2 in R^n (n = 2 or 3), are studied for ageneral annular bounded domain Ω with a smooth inner boundary (partial deriv)Ω_1 and a smoothouter boundary (partial deriv)Ω_2, where a finite number of piecewise smooth Robin boundaryconditions (partial deriv/(partial deriv)n_j + γ_j)φ = 0 on the components Γ_j(j = 1, …, k) of(partial deriv)Ω_1 and on the components Γ_j(j = k + 1, …, m) of (partial deriv)Ω_2 areconsidered such that (partial deriv)Ω_1 = ∪_(j = 1)~kΓ_j and (partial deriv)Ω_2 = ∪_(j = k +1)~mΓ_j and where the coefficients γ_j(j = 1, …, m) are piecewise smooth positive functions. Someapplications of Θ(t) for an ideal gas enclosed in the general annular bounded domain Ω are *** results are also obtained.

关键词： inverse problem heat kernel eigenvalues Robin boundary conditions classical ideal gas

Systematic review of centrifugal valving based on digital twin modeling towards highly integrated lab-on-a-disc systems

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Microsystems & Nanoengineering 2021年第6期7卷 45-70页

作者： Jens Ducrée School of Physical Sciences Dublin City UniversityDublinIreland

Current,application-driven trends towards larger-scale integration(LSI)of microfluidic systems for comprehensive assay automation and multiplexing pose significant technological and economical challenges to *** virtue of their intrinsic capability for powerful sample preparation,centrifugal systems have attracted significant interest in academia and business since the early *** review models common,rotationally controlled valving schemes at the heart of such“Lab-on-a-Disc”(LoaD)platforms to predict critical spin rates and reliability of flow control which mainly depend on geometries,location and liquid volumes to be processed,and their experimental *** absence of larger-scale manufacturing facilities during product development,the method presented here facilitates efficient simulation tools for virtual prototyping and characterization and algorithmic design optimization according to key performance *** virtual in silico approach thus significantly accelerates,de-risks and lowers costs along the critical advancement from idea,layout,fluidic testing,bioanalytical validation,and scale-up to commercial mass manufacture.

关键词： centrifugal advancement modeling

New DySrAlO_4 Compound Synthesis and Formation Process Correlations for LnSrAlO_4(Ln=Nd,Gd,Dy) Series

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Acta Metallurgica Sinica(english Letters) 2016年第5期29卷 450-456页

作者： e.A.Tugova New Inorganic Materials Laboratory Ioffe Institute

For the first time, DySrA104 of K2NiF4-type structure was synthesized. The parameters of DySrA104 ele- mentary unit cell are determined as follows： a = 0.368 （4） nm, c = 1.229 （2） nm, V = 0.166 （4） nm3. The research of the complex aluminates ZnSrA104 （Ln = Nd, Gd, Dy） solid-state process demonstrated the change of the formation mecha- nism among LnSrA104 （Ln = Nd, Gd, Dy） series from DySrA104 oxide. The performed analysis provided a possibility to realize why chemists couldn＇t get DySrA104 for a long period of time.

关键词： Rare earths Oxide materials K2NiF4-type structure Solid-state reactions Phase formation

Multi-revolution low-thrust trajectory optimization using symplectic methods

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Science China(Technological Sciences) 2020年第3期63卷 506-519页

作者： e ZhiBo GUZZeTTI Davide School of Aerospace engineering Tsinghua UniversityBeijing 100084China Department of Aerospace engineering Auburn UniversityAuburn AL 36849USA

Optimization of low-thrust trajectories that involve a larger number of orbit revolutions is considered as a challenging *** paper describes a high-precision symplectic method and optimization techniques to solve the minimum-energy low-thrust multi-revolution orbit transfer problem. First, the optimal orbit transfer problem is posed as a constrained nonlinear optimal control problem. Then, the constrained nonlinear optimal control problem is converted into an equivalent linear quadratic form near a reference solution. The reference solution is updated iteratively by solving a sequence of linear-quadratic optimal control sub-problems, until convergence. each sub-problem is solved via a symplectic method in discrete form. To facilitate the convergence of the algorithm, the spacecraft dynamics are expressed via modified equinoctial elements. Interpolating the non-singular equinoctial orbital elements and the spacecraft mass between the initial point and end point is proven beneficial to accelerate the convergence process. Numerical examples reveal that the proposed method displays high accuracy and efficiency.

关键词： low-thrust trajectory optimization symplectic method multi-revolution transfers