基于有补T-范的F-命题演算和一类F-控制模型

本文利用有补T-范建立了一类Fuzzy命题演算系统,给出了假言推理规则,推广了二值逻辑中命题演算的主要结果,且演算简单方便。作为它的应用,文末还给出了Fuzzy控制中的一个近似推理模型。     

弱内向型集压缩映射的正不动点

本文避开不动点指数,讨论了一类值域不完全在锥中的弱内向型映射,建立了弱内向型半紧1-集压缩映射的正不动点定理,以及弱内向型严格集压缩映射范数压缩型不动点定理,推广了Schauder定理及其它结果。     

弱紧型条件下Banach空间中微分方程的解

本文在弱紧型条件下讨论了Banach空间中常微分方程初值问题(1):u′=f(t,u),u(0)=u_0的可解性。首先,采用上、下解方法,较之文[1]使用的紧型条件较弱,并且比文[2]适用的弱序列完备的Banach空间更广,得到了定理1;然后,对f(t,u)可分解为式(19)的情形,采用上、下拟解方法,比文[3]的紧型条件较弱,得到了定理2。     

理想与现实——对西双版纳建筑创作的思考

本文联系西双版纳的建筑创作,对当地地域文化、建筑形式创作方法和建筑创作的指导思想进行了一些思考,提出了创造理想而又现实的建筑环境应注意的问题。     

翻斗车的行车制动性能分析

翻斗车有前桥制动和四轮制动两种型式。仅前驱动桥制动,其行车制动性能计算不同于汽车。四轮制动的翻斗车,其空载、满载理想制动力分配曲线与汽车恰相反。     

Density and Thermal Expansion of Liquid Au-Cu Alloys

The density of liquid Cu-Au alloys is measured using the technique of electromagnetic levitation, which entails producing a shadow image of the sample. The shadow is recorded by a digital CCD-camera, and the volume of the sample is calculated by an image processing algorithm. The density and thermal expansion of several alloys and the pure elements copper and gold are investigated at various temperatures above their melting points. In addition, the densities are also investigated as a function of the gold concentration at constant temperature. The measured values agree with literature data and with predictions obtained by molecular dynamics. It was found from data analysis that the ideal solution model applies.     

Vapor-Phase Helmholtz Equation for HFC-227ea from Speed-of-Sound Measurements

This work presents measurements of the speed-of-sound in the vapor phase of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea). The measurements were obtained in a stainless-steel spherical resonator with a volume of 900 cm³ at temperatures between 260 and 380 K and at pressures up to 500 kPa. Ideal-gas heat capacities and acoustic virial coefficients are directly produced from the data. A Helmholtz equation of state of high accuracy is proposed, whose parameters are directly obtained from speed-of-sound data fitting. The ideal-gas heat capacity data are fit by a functions and used when fitting the Helmholtz equation for the vapor phase. From this equation of state other thermodynamic state function are derived. Due to the high accuracy of the equation, only very precise experimental data are suitable for the model validation and only density measurements have these requirements. A very high accuracy is reached in density prediction, showing the obtained Helmholtz equation to be very reliable. The deduced vapor densities are furthermore compared with those obtained from acoustic virial coefficients with the temperature dependences calculated from hard-core square-well potentials.     

人居环境“阅读”——北京四合院居住文化

四合院建筑文化作为中华民族的特征之一,具有十分悠久的历史渊源,早在辽代就已经出现了,它不仅反映了中华民族的居住文化,也体现了一种“天然合一”的人文关系,本文就北京的四合院为例,浅析了它的历史背景和文化内涵。     

Weakly distributive domains(Ⅱ)

In our previous work (Inform. and Comput., 2005, 202: 87–103), we have shown that for any ω-algebraic meet-cpo D, if all higher-order stable function spaces built from D are ω-algebraic, then D is finitary. This accomplishes the first of a possible, two-step process in solving the problem raised (LNCS, 1991, 530: 16–33; Domains and lambda-calculi, Cambridge Univ. Press, 1998) whether the category of stable bifinite domains of Amadio-Droste-G?bel (LNCS, 1991, 530: 16–33; Theor. Comput. Sci., 1993, 111: 89–101) is the largest cartesian closed full subcategory within the category of ω-algebraic meet-cpos with stable functions. This paper presents the results of the second step, which is to show that for any ω-algebraic meet-cpo D satisfying axioms M and I to be contained in a cartesian closed full sub-category using ω-algebraic meet-cpos with stable functions, it must not violate MI^∞. We introduce a new class of domains called weakly distributive domains and show that for these domains to be in a cartesian closed category using ω-algebraic meet-cpos, property MI^∞ must not be violated. Further, we demonstrate that principally distributive domains (those for which each principle ideal is distributive) form a proper subclass of weakly distributive domains, and Birkhoff’s M ₃ and N ₅ (Introduction to Lattices and order, Cambridge Univ. Press, 2002) are weakly distributive (but non-distributive). Then, we establish characterization results for weakly distributive domains. We also introduce the notion of meet-generators in constructing stable functions and show that if an ω-algebraic meet-cpo D contains an infinite number of meet-generators, then [D → D] fails I. However, the original problem of Amadio and Curien remains open.     

Experimental excitation and detection of angular harmonics in a step-index optical fiber

As an alternative to classical LP-modes used as a signal carrier in the optical fiber, we propose a superposition of angular harmonics that can be obtained as a special combination of LP-modes, which also shows modal properties in an optical fiber. Results of a number of natural experiments on selective excitation of both individual angular harmonics and their superposition are discussed. The text was submitted by the authors in English.