Computing Bisimulations for Finite-Controlπ-Calculus

Symbolic bisimulation avoids the infinite branching problem caused by instantiating input names with all names in the standard definition of bisimulation in π-calculus.However,it does not automatically lead to an efficient algorithm,because symbolic bisimulation is indexed by conditions on names,and directly manipulating such conditions can be computationally costly.In this paper a new notion of bisimulation is introduced,in which the manipulation of maximally consistent conditions is replaced with a systematic employment of schematic names.It is shown that the new notion captures symbolic bisimulation in a precise sense.Based on the new definition an efficient algorithm,which instantiates input names “on-the -fly“,is presented to check bisimulations for finite-control π-calculus.     

A functional presentation of Pi calculus

From the very beginning process algebra introduced the dichotomy between channels and processes. This dichotomy prevails in all present process calculi. The situation is in contrast to that withlambda calculus which has only one class of entities-the lambda terms. We introduce in this papera process calculus called Lamp in which channels are process names. The language is more uniform than existing process calculi in two aspects-. First it has a unified treatment of channels and processes.There is only one class of syntactical entities-processes. Second it has a unified presentation ofboth first order and higher order process calculi. The language is functional in the sense that lambda calculus is functional. Two bisimulation equivalences, barbed and closed bisimilarities, are proved to coincide.A natural translation from Pi calculus to Lamp is shown to preserve both operational and algebraic semantics. The relationship between lazy lambda calculus and Lamp is discussed.     

A predicate spatial logic for mobile processes

A modal logic for describing temporal as well as spatial properties of mobileprocesses, expressed in the asynchronous π-calculus, is presented. The logic has recur-sive constructs built upon predicate-variables. The semantics of the logic is establishedand shown to be monotonic, thus guarantees the existence of fixpoints. An algorithm isdeveloped to automatically check if a mobile process has properties described as formulasin the logic. The correctness of the algorithm is proved.     

国产高强度Q960钢高温蠕变及其对钢柱抗火性能影响

为获得国产高强度Q960钢高温下蠕变应变,对Q960钢进行高温拉伸蠕变试验,得到不同温度和应力水平下的蠕变应变-时间曲线,基于试验数据,提出适用于Q960钢结构抗火分析的蠕变模型.采用有限元模型分析蠕变效应对Q960钢柱抗火性能的影响,得到标准升温条件下无防火保护Q960钢柱的临界温度,并与《建筑钢结构防火技术规范》(...     

Chemical modification of ethylacetoacetate with ASB in aqueous medium

Ethylacetoacetate (EAA) was mixed with aluminum sec-butoxide (ASB) in aqueous medium. The molar ratio among aluminum sec-butoxide, water, and ethylacetoacetate was 1:200:1. Water diluted nitric acid was added into the mixture until it finally transformed into transparent solution. TEM analysis showed that the surfaces of the colloidal particles with EAA were not as clean as those without EAA, implying the formation of a surface modification layer around the colloidal particle. The IR spectra analysis revealed that with the addition of EAA two characteristic peaks of EAA at 1 731 cm⁻¹ and 1 642 cm⁻¹ associated with C=O stretching vibrations were red-shifted to 1 619 cm⁻¹ and 1 530 cm⁻¹, respectively, indicating the occurrence of the chemical modification reaction among the C=O bonds of EAA and the surface Al-OH bonds of the particles., Furthermore it was confirmed by UV spectra analysis that the UV absorption band of EAA underwent 26 nm of red-shift as a result of the formation of the six-membered ring of the complex between ethylacetoacetate and ASB. It was examined that the chemical modification could be photolyzed by the UV illumination with a wavelength shorter than 270 nm due to the excitation of π − π * transition in the complex. Funded by the Doctoral Fund of University of Jinan (No. XBS0812)     

Organic-Inorganic Hybrid Materials Based on the Incorporation of Polysilicic Acid Nanoparticle (PN) with Organic Polymers. 3. Shrinkage Characteristics in the Cure of Unsaturated Polyester Resin in the Presence of a Modified PN

The polysilicic acid nanoparticle (PN) was modified by the reaction of silanol group on its surface with silyl group (–Si(OR)₃) containing modifiers such as phenyltrimethoxylsilane (PTS), 2-(p-styryl)ethyltrimethoxylsilane (SETS), and 3-(trimethoxylsilyl)propyl methacrylate (TPMA), respectively, to afford modified PNs (M-PNs) including P-PN, S-PN, and T-PN. P-PN, S-PN and T-PN were mixed, respectively, with unsaturated polyester resin (UP) in styrene, UP/St, and then let homogeneous solutions cure at 150°C to produce transparent hybrid materials, UP/St/P-PN, UP/St/S-PN, and UP/St/T-PN. It was found that the M-PNs could not only act as low-profile additives (LPAs) to reduce the shrinkage of the hybrids during curing but also enhance their dynamic mechanical properties. The shrinking mechanism of the hybrids during curing and the interfacial force between M-PNs and UP/St matrix, which plays an important role in shrinking control and properties of hybrid, were studied in detail.     

Differentiating random upper semicontinuous functions under the integral sign

In this paper we analyze sufficient conditions to guarantee the differentiability under the integral sign of a certain class of random upper semicontinuous functions depending on a real-valued parameter. Several concepts of differential for this mappings are considered: the Fréchet differentiability of the support function, the π-differentiability, the De Blasi differentiability, and thes-differentiability.     

960 MPa高强度钢材轴压构件整体稳定性能试验研究

为研究960 MPa高强度钢材轴压构件的整体稳定性能,对6个焊接工字形和等边箱形截面试件进行了静力试验研究,测量了试件的几何初弯曲、荷载初偏心以及截面残余应力分布等初始缺陷,分析了试件的失稳破坏形态,得到了整体稳定承载力,并与规范设计曲线进行了对比分析。利用试验结果验证了有限元分析模型,并进行参数分析。研究结果表明：试件的破坏模态均为整体弯曲失稳,除两个几何初始缺陷过大的试件外,其他试件的整体稳定系数试验值均明显高于规范设计值;参数分析结果表明,960 MPa钢材焊接截面轴压构件的整体稳定系数较普通钢材显著提高,建议采用GB 50017-2003中的a类柱子曲线设计此类轴压构件,同时拟合了960 MPa高强度钢材的柱子曲线公式。     

Supramolecular structure of S-(+)-marmesin—a linear dihydrofuranocoumarin

The title compound, C₁₄H₁₄O₄, a linear dihydrofuranocoumarin, was isolated from the bark ofAegle marmelos, a plant widely used in Ayurvedic system of medicine for the treatment of various ailments. The crystal structure was determined from X-ray diffraction data using direct methods. The compound crystallizes into monoclinic space group P2₁ with unit cell parameters:a] = 5.721(1) Å, b= 13.810(1) Å, c= 7.864(2) Å, β = 100.39(1)°, Z = 2. The structure was refined by full-matrix least-squares to a finalR value of 0.0523 for 1184 observed reflections. The benzopyran moiety is perfectly planar. The dihedral angle between the pyrone and benzene rings is 0.3(1)°. The furan ring has a 2α-envelope conformation. The molecules are linked by O-H…O hydrogen bonds into chains and these chains are linked into sheets by C-H…O hydrogen bonds. Further, the π-π stacking and C-H…π (arene) interactions link all of the sheets into a supramolecular structure.     

Metal Complexes of π-Conjugated Polymers

π-Conjugated chelating polymers such as poly(2,2′-bipyridine-5,5′-diyl), poly(1,10-phenanthroline-3,8-diyl), and salophen polymers have been prepared by organometallic polycondensations. The obtained polymers form metal complexes with various metal species such as [Ru(bpy)₂]²⁺ and CuCl₂. Metal complexes of π-conjugated ligands are also polymerized by dehalogenative organometallic polycondensations. Some of the metal complexes of π-conjugated polymers exhibit electrical conducting nature and show catalytic activity for redox reactions.