行进在钢丝绳上——校园暴力症结何解

专题背景"青春是一个可怕的东西:它是由穿着高筒靴和化装服的孩子在上面踩踏的一个舞台……他们假装的激情和幼稚的姿态会突然变成了一个灾难的现实。"(昆德拉)来自懵懂的孩子的暴力,像一个怪兽,它之所以强大,是因为我们还没有承受的准备,"天地君亲师"的一厢情愿抵挡不住解构的消解。一边是整个社会满心的期望,一边是无法预知的青春的冲动,有时,教师真的是行进在一道钢丝绳上。

“岁赋其二”该作何解

初中语文教材第六册《捕蛇者说》中有这样一句:“其始,太医以王命聚之,岁赋其二,募有能捕之者,当其租入。”教材将“岁赋其二”注解为“每年征收两条蛇”。

新三板困境何解

2017年,中国证券市场冰火两重天。一方面,证监会对IPO监管＂动了真格＂,在日趋严厉的IPO审核下,拟上市企业IPO通过率持续降低。但是,主板和中小创市场仍然火爆,500多家企业排起长长的队伍,等待IPO审核。与之相对应的是,曾经一度被寄予厚望的新三板风光不再,

对深度解读的解读

文本的深度解读并不是一味地在文本内容上的深挖与无限拔高，而是要能挖掘符合学生年段特点与“最近发展区”的、具有语文课程核心价值的教学内容。教师可以从“教语文”、“教阅读”、“教学习”等不同视角，以“纯粹的读者”、“当时的作者”、“背后的编者”、“当前的学者”、“冷静的教者”等不同身份，从文本“写什么”、“怎么写”、“为什么这么写”等不同层次。实现对文本的深度解读。

略论董仲舒春秋学研究的方法论问题——以“远近内外”为中心

通过何休来解释董仲舒的春秋学,是历代注释者共同遵循的方法。近来有学者从学理上否定了这一路径,认为董学未明的症结正在于此,力图突破何休的框架另立新说,并举"远近内外"问题为例。本文从该例证出发,阐述新旧两种解说,分析出新说错误的原因在于误解了何休的"义例"。以此广论何休的"义例"与董仲舒"《春秋》无达辞"观念之间的关系,重申"以何解董"的方法论问题。

The MAP/PH(PH/PH)/1 Discrete-time Queuing System with Repairable Server

In this paper, we discuss a discrete time repairable queuing system with Markovian arrival process, where lifetime of server, service time and repair time of server are all discrete phase type random variables. Using the theory of matrix geometric solution, we give the steady state distribution of queue length and waiting time. In addition, the stable availability of the system is also provided.

Novel Stilbene Glycosides from Polygonum multiflorum

Two new stilbene glycosides (1 and 2), together with nine known compounds (3-11), were isolated from the water extract of Polygonum multiflorum Thunb. The structures of the new compounds were elucidated by their chemical properties and spectroscopic analyses, including extensive 2D NMR experiments. Compound 2 showed strong DNA cleavage activity, and compounds 1, 2 and 10 (2, 3, 4′, 5_tetrahydroxy_ trans _stilbene_2_O_β_ D _glucopyranoside) exhibited significant inhibition of lipid peroxidation.

Numerical Simulation of Water Mitigation Effects on Shock Wave with SPH Method

The water mitigation effect on the propagation of shock wave was investigated numerically. The traditional smoothed particle hydrodynamics (SPH) method was modified based on Riemann solution. The comparison of numerical results with the analytical solution indicated that the modified SPH method has more advantages than the traditional SPH method. Using the modified SPH algorithm, a series of one-dimensional planar wave propagation problems were investigated, focusing on the influence of the air-gap between the high-pressure air and water and the thickness of water. The numerical results showed that water mitigation effect is significant. Up to 60% shock wave pressure reduction could be achieved with the existence of water, and the shape of shock wave was also changed greatly. It is seemly that the small air-gap between the high-pressure air and water has more influence on water mitigation effect.

Schroedinger Flows to Symmetric Spaces and the Second Matrix-AKNS Hierarchies

This article gives a unified geometric interpretation of the second Matrix-AKNS hierarchies via Schroedinger flows to symmetric spaces of Kaehler and paraKaehler types.

Geometric Mean Decomposition Based Hybrid Precoding for Millimeter-Wave Massive MIMO

Hybrid precoding can reduce the number of required radio frequency(RF)chains in millimeter-Wave(mmWave) massive MIMO systems. However, existing hybrid precoding based on singular value decomposition(SVD) requires the complicated bit allocation to match the different signal-to-noise-ratios(SNRs) of different sub-channels. In this paper,we propose a geometric mean decomposition(GMD)-based hybrid precoding to avoid the complicated bit allocation. Specifically,we seek a pair of analog and digital precoders sufficiently close to the unconstrained fully digital GMD precoder. To achieve this, we fix the analog precoder to design the digital precoder, and vice versa. The analog precoder is designed based on the orthogonal matching pursuit(OMP) algorithm, while GMD is used to obtain the digital precoder. Simulations show that the proposed GMD-based hybrid precoding achieves better performance than the conventional SVD-based hybrid precoding with only a slight increase in complexity.

Heisenberg Model in a Rotating Magnetic Field

We study the Hcisenberg moder under the influence of a rotating magnetic field. By using a time- dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves no chronological product. The spin vectors (mean values of the spin operators) are obtained as explicit functions of time in the most general case. A series of cyclic solutions are presented. The nonadiabatic geometric phases of these cyclic solutions are caleulated, and are expressed in terms of the solid angle subtended by the closed trace of thc total spin vector, as well as in terms of those of the individual spins.

A bearing fault feature extraction method based on cepstrum pre-whitening and a quantitative law of symplectic geometry mode decomposition

In order to extract the fault feature of the bearing effectively and prevent the impact components caused by bearing damage being interfered with by discrete frequency components and background noise,a method of fault feature extraction based on cepstrum pre-whitening(CPW)and a quantitative law of symplectic geometry mode decomposition(SGMD)is proposed.First,CPW is performed on the original signal to enhance the impact feature of bearing fault and remove the periodic frequency components from complex vibration signals.The pre-whitening signal contains only background noise and non-stationary shock caused by damage.Secondly,a quantitative law that the number of effective eigenvalues of the Hamilton matrix is twice the number of frequency components in the signal during SGMD is found,and the quantitative law is verified by simulation and theoretical derivation.Finally,the trajectory matrix of the pre-whitening signal is constructed and SGMD is performed.According to the quantitative law,the corresponding feature vector is selected to reconstruct the signal.The Hilbert envelope spectrum analysis is performed to extract fault features.Simulation analysis and application examples prove that the proposed method can clearly extract the fault feature of bearings.

Self-Similar Solutions of Three-Dimensional Navier-Stokes Equation

In this article we will present pure three dimensional analytic solutions for the Navier-Stokes and the continuity equations in Cartesian coordinates. The key idea is the three-dimensional generalization of the well-known self-similar Ansatz of Barenblatt. A geometrical interpretation of the Ansatz is given also. The results are the Kummer functions or strongly related. Our final formula is compared with other results obtained from group theoretical approaches.

A Remark on Concircularly Flat Totally Real Minimal Submanifolds in CP^n

Let M be a concircularly fiat totally real minimal submanifold in CP4. The infimum Vm of the volume V （M） of M is obtained, also the necessary and sufficient conditions of ＂V（M）=Vm＂ is given.

Schmidt Decomposition of Quaternion Matrix and the Orthonormalization of Vectors in a Generalized Unitary Space

In this paper we derive a practical method of solving simultaneously the problem of Schmidt decomposition of quaternion matrix and the orthonormalization of vectors in a generalized unitary space by using elementary column operations on matrices over the quaternion field.

Mathematical Model and Simulation of Cutting Layer Geometry in Orthogonal Turn⁃Milling with Zero Eccentricity

Orthogonal turn-milling is a high-efficiency and precision machining method.Its cutting layer directly affects chip formation,cutting forces,and chatter,and further affects tool life,machining quality,etc.We studied The cutting layer geometry(CLG)in orthogonal turn-milling with zero eccentricity(OTMZE)is studied to explore orthogonal turn-milling cutting layer formation process.OTMZE principles of motion and formation processes are analyzed statically without considering kinetic influences.Mathematical models of the entrance and exit angles,cutting thickness,and cutting depth are established.In addition,these models are validated experimentally and some influences of cutting parameters on the tool cutting layer are analyzed.The results show that OTMZE cutting layer formation can be divided into two stages,chip shapes are nearly consistent with the simulated CLGs,and the most influencial parameter in affecting the cutting layer is found to be the tool feed per revolation of workpiece fa,followed by the ratio of the tool and workpiece speedsλand the cutting depth ap.These models and results can provide theoretical guidance to clarify formation processes and quantitatively analyze changes in cutting layer geometry during OTMZE.In addition,they offer theoretical guidelines for cutting forces and chatter.

Stability for F-Harmonic Maps

In this paper, the author discusses the stable F-harmonic maps, and obtains the Liouville-type theorem for F-harmonic maps into δ-pinched manifolds, which improves the ones in [3] due to M Ara.

From Tomar to Angra： Interpretative Hypothesis of Geometric Pattern Morphology

This paper is focused on the study of the urban form of Tomar, which was founded in Portugal by the Order of the Temple during the 12th century. It is centered on the site where the Order of the Temple was created, Jerusalem, and also on the Templar European headquarters, Paris, in Marais neighborhood; as well as on its headquarters in Portugal, Tomar; and finally, on Angra which was set up in Azores at the beginning of the Portuguese discoveries in 1427. While exploring possible Templar principles on setting up medieval geometric cities, the aim of this paper is to expose that Tomar is a truly relevant case on that process and, therefore, that Portugal have had a significant role on medieval geometric urbanism. The achievements of this paper show that the selected territories share common settlement principles which are based on both similar geometric rules and analogous hierarchy schemes. Regarding that, it will be possible to state that cultural and population exchanges with France should not be considered as the sole factor to shape European medieval urbanity. Portugal should have had a role on that process, too. At least, it should be possible to explore other hypothesis on further pieces of research, according to the exposed arguments.

Vacuum Solutions of Classical Gravity on Cyclic Groups from Noncommutative Geometry

Based on the observation that the moduli of a link variable on a cyclic group modify Connes' distance on this group, we construct several action functionals for this link variable within the framework of noncommutative geometry. After solving the equations of motion, we find that one type of action gives nontrivial vacuum solution for gravity on this cyclic group in a broad range of coupling constants and that such a solution can be expressed with Chebyshev's polynomials.

Effect of Configuration on Mass Transfer in a Filter-press Type Electrochemical Cell

Effect of configuration （structure of electrode, interelectrode gap, positions of inlet and outlet, volume of the cell and additional nets） on mass transfer characteristic of a filter-press type electrochemical cell has been studied. The mass transfer coefficients on the electrodes were obtained by using the well-known technique based on the determination of limiting diffusion current. It is found that mass transfer coefficients with mesh electrode are greater than that of with plate electrode. Mass transfer coefficient is decreased with interelectrode gap. While interelectrode gap achieved a certain value （7 ram）, mass transfer coefficient is steady, no more declining. Mass transfer characteristic for different positions of inlet and outlet are different and dimensionless number groups correlated equations are obtained by experiment. Mass transfer characteristic is the best when inlet located on the top and outlet on the bottom of the cell respectively. While magnified the volume of the cell to eight times, mass transfer characteristic changes little. Mass transfer characteristic without nets is lower than that of with additional nets in the exit region, but higher than that of with additional nets in the entry region.