Q2Chemistry: A quantum computation platform for quantum chemistry

Quantum computers provide new opportunities for quantum chemistry. In this article,we present a versatile, extensible, and efficient software package, named Q2Chemistry, for developing quantum algorithms and quantum inspired classical algorithms in the field of quantum chemistry. In Q2Chemistry, the wave function and Hamiltonian can be conveniently mapped into the qubit space, then quantum circuits can be generated corresponding to a specific quantum algorithm already implemented in the package or newly developed by the users. The generated circuits can be dispatched to either a physical quantum computer, if available, or to the internal virtual quantum computer realized by simulating quantum circuits on classical computers. As demonstrated by our benchmark simulations, Q2Chemistry achieves excellent performance in simulating medium scale quantum circuits using the matrix product state algorithm. Applications of Q2Chemistry to simulate molecules and periodic systems are given with performance analysis.     

Exponential Stability of the Euler-Bernoulli Beam Equation with External Disturbance and Output Feedback Time-Delay

This paper concerns the stability of a one-dimensional Euler-Bernoulli beam equation with external disturbance and output feedback time-delay, in which the disturbance is bounded by an exponential function. In order to estimate disturbance, the authors design an estimator of disturbance,which is composed of two parts: One is the system measurement that is called the eigen-measurement,another is a time-variant estimator of disturbance. Thus, the feedback controller which is based on the estimate of the disturbance is designed to stabilize the system. The finite-time stability of the system under this control law is proved by Lyapunov function method. Finally, some numerical simulations on the dynamical behavior of the closed-loop system is presented to show the correctness of the result.     

尧舜禅让传说的隐性社会结构探析

依据结构主义方法分析,尧舜禅让传说背后隐藏着两大深层社会结构:一是五官合议制,二是龙凤婚盟.依据前者,中央帝产生要经过四方部落首领同意;依据后者,龙凤两族舅甥相传,轮流执政.在相当长的时期里,两种结构是叠合在一起的.随着父系制逐步确立,舅甥疏远而父子相亲,五官合议及龙凤两族首领轮流执政的旧制被破坏,古史传说时代的禅让制宣告终结.     

Ion transport-related resistive switching in film sandwich structures

Resistive switching memories based on ion transport and related electrochemical reactions have been extensively studied for years. To utilize the resistive switching memories for high-performance information storage applications, a thorough understanding of the key information of ion transport process, including the mobile ion species, the ion transport paths, as well as the electrochemical reaction behaviors of these ions should be provided for material and device optimization. Moreover, ion transport is usually accompanied by processes of microstructure modification, phase transition, and energy band structure variation that lead to further modulation of other physical properties, e.g., magnetism, optical emission/absorbance, etc., in the resistive switching materials. Therefore, novel resistive switching memories that are controlled through additional means of magnetic or optical stimulus, or demonstrate extra functionalities beyond information storage, can be made possible via well-defined ion transportation in various switching materials and devices. In this contribution, the mechanism of ion transport and related resistive switching phenomena in thin film sandwich structures is discussed first, followed by a glanceat the recent progress in the development of high-performance and multifunctional resistive switching memories. A brief perspective of the ion transport-based resistive switching memories is addressed at the end of this review.     

综合自动化企业的全集成模型研究

分析了现代企业向综合自动化发展的趋势及相应的全集成要求，通过建立功能模型、信息模型和过程模型间的映射关系形成了综合自动化企业的全集成模型，并利用 Ｉ Ｅ Ｄ Ｆ０ 图、 Ｉ Ｄ Ｅ Ｆ１ Ｘ 图和改造的 Ｐｅｔｒｉ 图作了结构化描述，此外，根据面向对象思想，探讨了模型中对象封装和继承的方式，为企业实施信息、物料、过程集成乃至并行工程提供了建模工具．     

北京大学生消费现状调查研究

为了更深入地了解北京大学生消费现状和存在问题,本研究借助于网络调查平台收集北京大学生消费情况和消费观念的数据,按照不同性别、年级和所在家庭收入情况对调查数据进行定量和定性分析.数据显示,总体上北京大学生能够从自身家庭收入条件出发,表现出合理的消费行为.本研究的有趣发现是:家庭收入越低的学生,投资意愿却越强;来自收入偏上家庭的学生经济独立意识较弱;女生更容易冲动消费.这些发现未见文献报道.本文对其它调查数据也进行了分析并提出建设性意见.     

p-Laplacian-类Duffing方程正周期解的存在性与唯一性

用Manasevich-Mawhin连续定理,证明了一类p-Laplacian-类Duffing方程正周期解的存在性和唯一性,得到新的结论并改进前人的一些结论.     

Direct and indirect effects of solar variations on stratospheric ozone and temperature

We have used a fully coupled chemistry-climate model (WACCM) to investigate the relative importance of the direct and indirect effects of 11a solar variations on stratospheric temperature and ozone. Although the model does not contain a quasi-biennial oscillation (QBO) and uses fixed sea surface temperature (SST), it is able to produce a second maximum solar response in tropical lower stratospheric (TLS) temperature and ozone of approximately 0.5 K and 3%, respectively. In the TLS, the solar spectral variations in the chemistry scheme play a more important role than solar spectral variations in the radiation scheme in generating temperature and ozone responses. The chemistry effect of solar variations causes significant changes in the Brewer-Dobson (BD) circulation resulting in ozone anomalies in the TLS. The model simulations also show a negative feedback in the upper stratosphere between the temperature and ozone responses. A wavelet analysis of the modeled ozone and temperature time series reveals that the maximum solar responses in ozone and temperature caused by both chemical and radiative effects occur at different altitudes in the upper stratosphere. The analysis also confirms that both the direct radiative and indirect ozone feedback effects are important in generating a solar response in the upper stratospheric temperatures, although the solar spectral variations in the chemistry scheme give the largest solar cycle power in the upper stratospheric temperature.     

坚持科学发展观 建设绿色经济市

文章阐述了建设绿色经济市的思路、条件和构想，强调了走以最有效利用资源和保护环境为基础的循环经济之路，是全面建设小康社会加快绿色经济建设的必然选择。     

Roles of flanking sequences in the binding between unimolecular parallel-stranded G-quadruplexes and ligands

G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug development.As a motif existed in physiological condition,flanking sequences are an important part of G-quadruplexes but the study on the impact of flanking sequences on (G-quadruplex)-ligand binding is rarely reported.In this paper,the effects of flanking sequences on binding affinity between a series of unimolecular parallel-stranded G-quadruplex sequences derived from c-myc oncogene promoter (termed as c-myc G-quadruplexes) and their ligands are discussed in detail.The results showed that the flanking sequences on c-myc G-quadruplexes play key roles in (G-quadruplex)-ligand interaction.When a c-myc G-quadruplex is bound to its ligands,the flanking sequences might form a binding cavity above the terminal G-quartet,which could provide a suitable site for ligands to dock in.Moreover,the bases on flanking sequences could interact with ligand through π-π stacking,and finally form a sandwich-stacking mode (terminal G-quartet,ligand and bases on the flanking sequence).This mode could stabilize the (G-quadruplex)-ligand complex effectively and enhance the binding affinity dramatically.However,flanking sequences are also found to exhibit steric hindrance effect which could impede the (G-quadruplex)-ligand binding.