改进Elman神经网络在短期热负荷预测中的应用

热电厂的短期热负荷预测在城市集中供暖中起着至关重要的作用,直接影响热电厂的经济效益和热能利用率。电厂的短期热负荷一般采用神经网络预测模型进行预测,而BP神经网络应用最为广泛。Elman神经网络算法在BP神经网络基础上加入了承接层,作为一步延时算子,实现记忆能力,使系统具备适应时变能力,增强系统全局稳定性。但Elman神经网络算法模型的构造依然需要大量样本的支撑,而且输入层的变量多,导致预测时间依然很长,收敛速度慢。该文在Elman神经网络预测前,进行了相关系数预处理和对样本中异常值的平均化预处理,通过数据归一化运算,使Elman神经网络输入层变量大幅减少。仿真实验表明,改进的Elman神经网络算法使预测模型快速寻优,减少预测时间的同时明显提高预测精度。     

Synthesis of Ionic Ultramicroporous Polymers for Selective Separation of Acetylene from Ethylene

The design of highly stable and efficient porous materials is essential for developing breakthrough hydrocarbon separation methods based on physisorption to replace currently used energy-intensive distillation/absorption technologies. Efforts to develop advanced porous materials such as zeolites, coordination frameworks, and organic polymers have met with limited success. Here, a new class of ionic ultramicroporous polymers (IUPs) with high-density inorganic anions and narrowly distributed ultramicroporosity is reported, which are synthesized by a facile free-radical polymerization using branched and amphiphilic ionic compounds as reactive monomers. A covalent and ionic dual-crosslinking strategy is proposed to manipulate the pore structure of amorphous polymers at the ultramicroporous scale. The IUPs exhibit exceptional selectivity (286.1–474.4) for separating acetylene from ethylene along with high thermal and water stability, collaboratively demonstrated by gas adsorption isotherms and experimental breakthrough curves. Modeling studies unveil the specific binding sites for acetylene capture as well as the interconnected ultramicroporosity for size sieving. The porosity-engineering protocol used in this work can also be extended to the design of other ultramicroporous materials for the challenging separation of other key gas constituents.     

湖北省保康县荆山玉地球化学特征及其成因分析

荆山玉是湖北省保康县新发现的一个玉石品种,形成于大陆边缘—洋盆区过渡带的热水沉积环境,为晚震旦世—早寒武世灯影组的一种硅质角砾岩:原地震碎角砾岩,由角砾和胶结物二部分构成,角砾局部可拼接;角砾成分为早期硅质岩碎裂产物,胶结物除早期硅质岩碎裂产物外,还有少量后期充填的石英、铁质等,受角砾、胶结物颗粒大小、裂隙发育程度不同的影响,后期热液改造程度不同,角砾和胶结物化学成分存在一定的差异,色调与铁质有关。荆山玉的形成主要经历了三个阶段的演化:第一阶段,低温150～225℃、弱氧化—弱还原条件下热水成因的硅质岩形成;第二阶段,热力膨胀外力作用下,硅质岩局部原地震碎形成硅质角砾岩,热水温度243～340℃,富氧氧化—贫氧过渡环境,红褐色的Fe~(3+)在胶结物、裂隙中富集;第三阶段,热水温度116～127℃、缺氧还原条件,黄色的Fe~(2+)在胶结物、裂隙中富集。     

油库发油过程中的HSE管理

叙述了石油库在发油过程中的HSE管理；发油过程中的危害识别，包括识别范围和内容；发油过程中风险评价的常用基本方法和常见问题；发油过程中危险源的管理控制，包括建立危险源网络图、加强现场监控和制定应急预案。     

A note on the Gauss-Jacobi quadrature formulae for singular integral equations of the second kind

A fast and efficient numerical method based on the Gauss-Jacobi quadrature is described that is suitable for solving Fredholm singular integral equations of the second kind that are frequently encountered in fracture and contact mechanics. Here we concentrate on the case when the unknown function is singular at both ends of the interval. Quadrature formulae involve fixed nodal points and provide exact results for polynomials of degree 2n − 1, where n is the number of nodes. Finally, an application of the method to a plane problem involving complete contact is presented.     

乙烯基硅氧烷改性苯丙乳液的研究

在苯乙烯 -丙烯酸酯乳液共聚反应后期 ,加入少量乙烯基硅氧烷 ,制得改性苯丙乳液 ,通过红外光谱初步确定了聚合物结构。研究了反应温度、反应时间、有机硅加入方式、乳化剂用量等因素对反应进程、乳液稳定性及涂膜性能的影响。     

纯净钢生产技术及现状

本文简述了近年来国外主要炼钢厂生产纯净钢钢中杂质元素控制技术的发展，系统分析了钢中氧、碳、氮、硫、磷、氢等元素在钢中行为和降低杂质元素的措施。     

Behaviour of Hydrogen in Nano-transition Metals

Nanocrystalline transition metals were prepared with Ar+H2 arc plasma method. The hydrogenmust be used during preparation to get a special nanrvparticles. The hydrogen plays an importantrole in the structure and state of nanocrystalline transition metals. The state of hydrogen andthe change of the nanocrystalline metal structure caused by hydrogen are called the behaviour ofhydrogen in nano-transition metals which includes the ability and function of storing hydrogenin the metals.     

磷脂产品的常用法规、术语、指标

介绍了有关组织对磷脂的法规、术语、指标及意义.