技术进步对中国火力发电部门要素偏向与能源强度的影响

在碳达峰、碳中和的背景下,中国电力部门的碳减排一方面依赖于能源结构的优化,另一方面也需要火力发电部门能源强度的降低。本文基于中国火力发电企业层面数据,在超越对数成本函数的框架中纳入企业研发投入、外商直接投资、环境规制3种技术进步来源,采用似不相关回归法估计成本函数系数,进而估算要素替代弹性,分析不同来源技术进步对要素投入及能源强度的影响,讨论技术进步的要素偏向性。研究结论发现：①企业研发投入、外商直接投资的技术溢出效应带来显著的中性技术进步和要素节约,均对能源强度下降有显著贡献;相较于东部企业和大型企业,中西部企业、小型企业的技术进步效应较弱。②环境规制主要通过设备更新等直接效应实现能源偏向性技术进步,而通过企业研发投入的间接机制实现技术进步的影响并不显著。因此,有必要通过促进创新成果推广应用、建设区域间企业交流合作平台、完善环境规制政策组合等措施,激励不同来源技术进步对中国火力发电行业能源要素节约、能源强度下降的作用。     

高次非线性薛定谔微分方程的新精确解

主要利用直接截断法来讨论非线性薛定谔微分方程： iu1＋uxx＋α0｜u｜^2u＋i[γ1uxx＋γ2｜u｜^2ux＋γ3（｜u｜^2）xu]=0 的精确解．借助于符号计算软件Maple,得到了此方程一些新的含Jacobi椭圆函数的精确解。     

Static and dynamic damage analysis of mass concrete in hydropower house of Three Gorges Project

This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite and infinite elements for simulating infinite foundation of hydropower station is adopted. A plastic-damage model based on continuum damage mechanics, which includes the softening and damage behavior under tension is considered for the concrete material. The dynamic equilibrium equations of motion are solved by using the HilberHughes-Taylor (HHT) time integration method. Firstly, the static damage response analysis of the hydropower station is conducted due to high tensile stress resulting from large water head and diameter of an inlet pipe. Then, on the basis of static simulation, the dynamic damage analysis of hydropower house subjected to earthquake motion is simulated. Numerical results show that under large water head and diameter of an inlet pipe of the project, the damages are mainly located near the top of the spiral case from the inlet section to the 0° section; under combined loadings of static loads and earthquake, the damages of the concrete surrounding the spiral case increase insignificantly; however, some damages occur on the side walls of the main powerhouse.     

对侦查讯问同步录音录像制度的反思

讯问同步录音录像制度对于遏制刑讯逼供、保护犯罪嫌疑人等都具有重要作用。任何制度的建立和运作都有赖于一系列相关制度作保障,我国在相关保障机制尚未建立健全的情况下就推行这一制度,不仅可能无法发挥该制度预期的作用,反而会造成相反的结果。解决问题的关键在于加强对侦查讯问过程的外部监督和制约,使得该制度得以真正发挥作用。     

发达国家职业教育推动校企合作的先进经验及对我国的启示

现阶段我国职业学校校企合作大多停留在以学校为主导的合作形式上,还存在企业积极性不高等问题。发达国家职业教育从法律保障、政府重视、政策倾斜等多方面推动校企合作的先进经验,为我国职业教育开展校企合作提供了借鉴。     

大地电磁模拟退火反演研究

主要介绍模拟退火算法的基本原理和实现步骤。将模拟退火算法引入MT资料反演,针对MT正演多参数和非线性的特点,采用合适的降温方式和选择机制,以提高运算速度和运算精度。结合具体的反演算法原理和实现方法,使用不同的MT正演理论模型进行验证,获得良好的的结果。     

一类非线性时滞系统的自适应动态面控制

针对一类严格反馈非线性时滞系统,提出了一种自适应神经网络动态面控制方案。通过引入一阶滤波器,避免了传统反演设计中的＂计算膨胀＂问题。通过构造恰当的Lyapunov-Krasovskii函数,对未知时滞项进行了补偿。此外,基于Lyapunov稳定性理论,证明了闭环系统所有信号半全局一致最终有界。最后,仿真实例表明了所提控制方案的有效性。     

一类具有分布时滞高阶微分方程的周期解

利用Mawhin重合度理论,研究了一类具有分布时滞的高阶P—Laplacian中立型微分方程,获得了其周期解存在性的一些新结果．     

基于人工神经网络的玉米价格短期预测研究

为获得更精确预测粮食价格的方法,引入了人工神经网络预测法,建立了一种改进的人工神经网络模型,并通过该模型自学习的特性对已获得粮食价格时间序列数据的波动规律与发展趋势实现记忆性的学习,最终预测出未来价格.结果表明：人工神经网络模型在预测价格问题上具有很高的精度;其方法不仅可行,而且适用性强,预测结果客观、合理,具有一定的研究价值和较好的应用前景.     

Fitting Nonlinear Latent Growth Curve Models With Individually Varying Time Points

Individual growth trajectories of psychological phenomena are often theorized to be nonlinear. Additionally, individuals’ measurement schedules might be unique. In a structural equation framework, latent growth curve model (LGM) applications typically have either (a) modeled nonlinearity assuming some degree of balance in measurement schedules, or (b) accommodated truly individually varying time points, assuming linear growth. This article describes how to fit 4 popular nonlinear LGMs (polynomial, shape-factor, piecewise, and structured latent curve) with truly individually varying time points, via a definition variable approach. The extension is straightforward for certain nonlinear LGMs (e.g., polynomial and structured latent curve) but in the case of shape-factor LGMs requires a reexpression of the model, and in the case of piecewise LGMs requires introduction of a general framework for imparting piecewise structure, along with tools for its automation. All 4 nonlinear LGMs with individually varying time scores are demonstrated using an empirical example on infant weight, and software syntax is provided. The discussion highlights some advantages of modeling nonlinear growth within structural equation versus multilevel frameworks, when time scores individually vary.