神经网络在电力系统无功优化中的应用

神经网络在处理非线性、多变量、多约束的电力系统无功优化问题方面有其特有的优势,但实际应用中仍存在局限性,把神经网络和其他优化算法结合用于此类问题的研究逐年增多.本文详细阐述了神经网络以及神经网络与其他优化算法相结合在电力系统无功优化中的应用以及今后的发展趋势.     

AAC砌块自由加载墙施工工法

AAC砌块自重轻、易切割、防火与保温性好,但其强度低、不能任意加载,开槽开洞局限较多,遇水湿胀且强度和保温性能变低。AAC砌块自由加载墙体施工工艺采用AAC砌块、页岩砖、素混凝土块混墙结构,通过BIM排块设计,在AAC砌块墙体中嵌入素混凝土块,在箱体集中处砌筑页岩砖墙体,以自由地适应加载、开槽开洞和墙体变形;利用表面网膜和界面封堵工艺,较好地解决了防渗防漏;利用砌块墙与页岩砖墙、混凝土梁柱间的厚度差,采用热桥咬合工艺,较好地解决了热桥。该工法系统地解决AAC砌块墙体的质量通病、使用局限,增强AAC砌块墙体的整体性、加载开槽开洞的便易性和防水性能,加上其工厂化生产与加工的特点,使其能更广泛地应用于室内外墙体。     

Kinetics of isothermal decomposition in polycrystalline β CuAlBe alloys

The kinetics of the microstructural evolution of the metastable β phase during isothermal aging in a Cu–22.60Al–3.26Be (at%) polycrystalline shape memory alloy has been studied by electrical resistivity measurements and microscopical examinations. With an isothermal treatment at around 820 K, the alloy rapidly decomposes into γ₂ phase with dendritic morphology, while between 670 K and 760 K the formation of α′ phase followed by the eutectoid decomposition is observed. A TTT diagram was estimated and the stability boundaries of the β phase in the studied alloy were compared with those of other Cu-based shape memory alloys.     

安全适用、经济合理的设计、施工、监理建筑幕墙

只有正确区分建筑幕墙和采光顶或金属屋面、建筑门窗及其它建筑外装饰，才能保证安全适用、经济合理的设计、施工、监理建筑幕墙，满足建筑效果的需要。     

Creep characteristics of glass reinforced cement under flexural loading

Tests are reported on the flexural creep behaviour and flexural strength characteristics of mortar specimens reinforced with 5.0% by weight glass fibres. The specimens were cut off from flat sheet materials produced by premixing and spray suction casting processes. It is shown that fibre reinforcement reduced the deflections under sustained flexural load. The results show unmistakably a very significant influence of the fibre reinforcement in reducing creep strains. Fibres were generally more effective in controlling compression creep than tensile creep. Strength reductions were observed with time which were insignificant in specimens produced with the spray suction method.     

试论正反艺术手法

文章就建筑设计中的“正反”艺术手法结合实例进行了分析。“正反”艺术手法是“对立统一”规律在建筑创作中的运用，它当为一种有效的创作手法。     

爆炸荷载作用下地下结构与围岩动力相互作用研究

爆炸荷载作用下结构的动力响应一直是热点的研究课题,但是对于地下支护结构与围岩在爆炸荷载作用下的相互作用机理研究还很少。爆炸荷载属于破坏荷载,用实验方法进行研究存在很大的困难,因此应用ANSYS/LS-DYNA非线性显式动力学有限元程序,采用流固耦合算法,对爆炸荷载作用下地下拱形结构与围岩的相互作用进行研究。研究结果表明:质点振幅和破碎区的大小与经验公式计算的数据基本吻合;不同TNT装药条件下,对于跨度较小(6m)的拱形支护结构,均发生剪切破坏形态,拱肩处峰值压力最大,成为结构受力的薄弱环节,设计中应采取加强措施。     

变结构动态贝叶斯网络的机制研究

传统的动态贝叶斯网络(Dynamic Bayesian networks, DBNs)描述的是一个稳态过程,而处理非稳态过程,变结构动态贝叶斯网络更适 用、更灵活、更有效.为了克服现有变结构离散 动态贝叶斯网络推理算法只能处理硬证据的缺陷,本文在深入分析变结构动态贝叶斯网络机制及其特 征的基础上,提出了变结构离散动态贝叶斯网络的 快速推理算法.此外,对变结构动态贝叶斯网络的特例,即数据缺失动态贝叶斯网络进行了定义并构建 了相应的模型.仿真实验验证了变结构离散动态贝 叶斯网络快速推理算法的有效性及计算效率.     

Self-consistent kinetic theory with nonlinear wave-particle resonances

We have developed, based on the oscillating-center transformation, a general theoretical approach for self-consistent plasma dynamics including, explicitly, effects of nonlinear(higherorder) wave-particle resonances. A specific example is then given for low-frequency responses of trapped particles in axisymmetric tokamaks. Possible applications to transport as well as nonlinear wave growth/damping are also briefly discussed.     

新城金矿Ⅴ#矿体-680m中段踏步式回采研究

回采顺序的合理选择有助于地下金属矿山控制地压活动、改善回采条件以及提高经济效益.新城金矿Ⅴ#矿体采用上向水平分层充填法回采,采场垂直矿体走向布置并按照“隔一采一”顺序分为一步回采和二步回采,这种回采顺序导致二步采场两侧均为充填体支撑,顶板条件较差.本研究以新城金矿Ⅴ#矿体-680 m中段为研究对象,基于原有的“隔一采一”回采顺序提出“踏步式回采”方案,通过FLAC3D软件模拟分析、比较2种方案对采场岩体稳定性的影响.数值模拟结果表明,无论采用“隔一采一”还是“踏步式回采”方案,在两侧为充填体支撑的情况下,中间矿体的回采条件均较差,但相比而言,“踏步式回采”在控制顶板变形、避免产生大范围塑性区方面优于“隔一采一”方案.本研究成果对类似矿山的矿体回采设计有重要的借鉴意义.