Experimental J estimation equations for single-edge-cracked bars in four-point bend: homogeneous and bi-material specimens

The present paper provides the plastic η factor solutions for J testing of single-edge-cracked specimens in four-point bend (SE(PB)), based on limit (slip line field) and detailed finite element limit analyses. Both homogeneous specimens and bi-material specimens with interface cracks are considered. Moreover, two different η factor solutions are developed, one for J (or C^* in creep crack growth testing) estimation based on the load-load line displacement (LLD) records, η_p^VLL, and the other J estimation based on the load-crack mouth opening displacement (CMOD) records, η_p^CMOD.It is found that the use of load-LLD records can be recommended only for testing deeply cracked SE(PB) specimens. Moreover, depending on how the LLD is measured, a different value of η_p^VLL should be used. On the other hand, the use of load-CMOD records is recommended for all possible crack lengths. Moreover, the proposed η_p^CMOD solution can be used not only for a homogeneous specimen but also for any bi-material specimen with an interface crack.     

Estimation procedure of J-resistance curves for SE(T) fracture specimens using unloading compliance

This work provides an estimation procedure to determine J-resistance curves for pin-loaded and clamped SE(T) fracture specimens using the unloading compliance technique and the η-method. A summary of the methodology upon which J and crack extension are derived sets the necessary framework to determine crack resistance data from the measured load vs. displacement curves. The extensive plane-strain analyses enable numerical estimates of the nondimensional compliance, μ, and parameters η and γ for a wide range of specimen geometries and material properties characteristic of structural and pipeline steels. Laboratory testing of an API 5L X60 steel at room temperature using pin-loaded SE(T) specimens with side-grooves provide the load-displacement data needed to validate the estimation procedure for measuring the crack growth resistance curve for the material. The results presented here produce a representative set of solutions which lend further support to develop standard test procedures for constraint-designed SE(T) specimens applicable in measurements of crack growth resistance for pipelines.     

Evidence for η6 Coordination to a Fullerene

Abstract

Evidence for the first η⁶ derivative of a fullerene, [MoC₆₀F₁₈(CO)₃] has been obtained from reaction between [Mo(CH₃CN)₃(CO)₃] and C₆₀F₁₈.     

(g,η)-增生算子及变分包含问题(英文)

在没有假定多值映射是连续映射的条件下,得到了(g,η)-增生算子、广义豫解算子和(g,η)-增生算子产生的广义Yosida近似的一些性质,并应用这些性质证明了一类变分包含问题的解的存在性.     

Experimental investigation of prechamber autoignition in a natural gas engine for cogeneration

A novel ignition concept based on autoignition in an unscavanged prechamber is currently being developed at the Laboratory for Industrial Energy Systems (LENI). On a single cylinder test engine a series of experimental runs (CR = 8.5-14, λ = 1 − 1.6, RPM = 1150/1500 min⁻¹) have been realized with natural gas as fuel, comparing the new ignition concept to standard spark ignition. The comparison is based on fuel efficiency and exhaust emissions (CO, THC, NO_x). The feasibility of operating the engine in autoignition mode has been demonstrated, and the potential of prechamber autoignition, in particular in the lean combustion regime, is indicated by the trends in fuel efficiency and emission concentration. The resistive heating of the prechamber walls has been shown to be an effective mean to trigger ignition. The prechamber could clearly be identified as primary ignition location. A reduction of the cycle-by-cycle variations - due to mixture fluctuations - is necessary to exploit the full potential of this engine concept.     

Least-squares problem for the quaternion matrix equation AXB+CYD=E over different constrained matrices

For any A=A ₁+A ₂ j∈Q ^n×n and η∈<texlscub>i, j, k</texlscub>, denote A ^{η H} =?η A ^H η. If A ^{η H} =A, A is called an $\eta$-Hermitian matrix. If A ^{η H} =?A, A is called an η-anti-Hermitian matrix. Denote η-Hermitian matrices and η-anti-Hermitian matrices by η HQ ^n×n and η AQ ^n×n , respectively.

By using the complex representation of quaternion matrices, the Moore–Penrose generalized inverse and the Kronecker product of matrices, we derive the expressions of the least-squares solution with the least norm for the quaternion matrix equation AXB+CYD=E over X∈η HQ ^n×n and Y∈η AQ ^n×n .     

二维超导η-Mo3C2薄膜的可控制备

二维超导体具有丰富的物理特性和非常广泛的潜在应用.最近,有报道制备出具有二维超导特性的α-Mo2C和面心立方Mo2C,这些材料为碳基超导的研究带来了新的方向.碳化钼具有多种晶体结构,除了目前已经被制备的种类外,二维碳化钼尚没有新的晶体结构被制备出来,这或许是因为在制备过程中缺乏额外的能量供给.在本工作中,我们进一步发展...     

Second-order duality for non-differentiable minimax fractional programming

In this paper, a second-order duality for a non-differentiable minimax fractional programming is formulated by generalizing the one developed by Husian et al. [Second order duality for minimax fractional programming, Optim. Lett. 3 (2009), pp. 277–286], for the minimax fractional programming. The weak, strong and strict converse duality theorems are proved for these programs under generalized η-bonvexity assumptions.     

纸机供汽系统热泵能量效率与 效率分析比较

对热泵运行的效率进行了分析比较,找出了能量效率（COP）值与[火用]效率（η）值在评价热泵时的差异,对计算实例进行了COP分析和η分析并加以评价对比,并计算出了热泵实际的COP值、η和[火用]损失率（Ω）．研究表明,η和Ω值在评价热泵装置时比COP评价具有更多优势,因此采用η和Ω来评价一个热泵系统运行的可用能效率更为有效．     

高性能水性阻尼涂料的研究

介绍了高分子材料的阻尼机理,采用乳液共混的方法来实现拓宽阻尼温域。通过对乳液共混方法、云母粉粒径和添加量的选择、增稠剂和纤维的筛选,研制的阻尼涂层具有阻尼温域宽、复合损耗因数高、减振降噪性能好、机械性能佳等特性。