思想工作要打破时空界限

思想工作要打破时空界限杨思兴，何会某部一位优秀指导员在谈及工作体会时，意味深长他说：“常言道‘儿行千里母担忧，，我们当指导员的，也要用母亲一样的情怀时刻关注战士们的一言一行，做工作不能有时空界限，要让工作跟着战士走。”这番话，讲得很有道理。指导员作为...

近木星轨道异常加速的时空引力(时引场)研究

近木点附近的异常加速问题目前还没有一个确切的说法,美国宇航局至少五艘探测器掠过木星点附近的时候都发现了异常。探测器通过引力弹弓进入木星轨道,轨迹是闭合的,渐近速度与理论计算的情况并不相同。此时航天器速度的增加比飞越地球时产生的典型的异常加速要大几百倍。质量或描述为质量对时空场的弯曲效应是万有引力的源头。但这不是产生引力的唯一方法。本研究将物理研究领域分为粒子物理界和时空能量界。这两个界的沟通桥梁有基于真空对称自发破却和宇称不守恒原理构建的场。希格斯场是其中的一种。

今史辨:20世纪国乐思想的从新定位

该文系一篇关于二十世纪国乐思想回以从新定值的学术文论。以中西音乐文化关系的当代研究为切入口，涉及二十世纪中国音乐在西方文化（音乐）冲击下发生历史断层的问题；因西方音乐介入使中西音乐文化发生关采，进而导致中国现代专业音乐产生的问题；以及对中西音乐文化关系的认识问题。这一个中心（中西音乐文化关系）和两个基本点（发生两代历史断层与现代专业音乐成型）构成了二十世纪当代中国专业音乐史。本交通过兰会有关中国新音乐导国乐思想的言论，再上溯近现代有关人士的国乐主张，进而提出对二十世纪国乐思想从新定位的基本前提与进行当代中国音乐史辨的支点条件；不同文化的时空界转换，不同文化的约定素转换。认为，国乐的根本出路在于，超越非本值文化的人为隔阂写历史屏障，向自然灵；因而，对国乐思想的从新定位也必须在反思历史断层和参与文化转型的过程中实现［解体／重生〕的同位转换。

Variable-coordinate forward modeling of irregular surface based on dual-variable grid

The mapping method is a forward-modeling method that transforms the irregular surface to horizontal by mapping the rectangular grid as curved; moreover, the wave field calculations move from the physical domain to the calculation domain. The mapping method deals with the irregular surface and the low-velocity layer underneath it using a fine grid. For the deeper high-velocity layers, the use of a fine grid causes local oversampling. In addition, when the irregular surface is transformed to horizontal, the flattened interface below the surface is transformed to curved, which produces inaccurate modeling results because of the presence of ladder-like burrs in the simulated seismic wave. Thus, we propose the mapping method based on the dual-variable finite-difference staggered grid. The proposed method uses different size grid spacings in different regions and locally variable time steps to match the size variability of grid spacings. Numerical examples suggest that the proposed method requires less memory storage capacity and improves the computational efficiency compared with forward modeling methods based on the conventional grid.

我的课余生活

我没有什么爱好,课余生活当然就不怎么丰富,甚至可以说是乏味。于是书成了我的宝贝,看书是我的最爱。只要一拿起书来,我就把什么都忘了,我的灵魂长上翅膀,跟随书中的故事,突破时空界限到处漫游。

Seasonal changes in the demersal nekton community off the Changjiang River estuary

The diversity,community structure and seasonal variation in demersal nekton off the Changjiang(Yangtze)River estuary was evaluated using monthly trawl survey data,collected between December 2008 and November 2009.A total of 95 species(56 teleosts,11 cephalopods,and 28 decapod crustaceans)from 69 genera,49 families and 15 orders were collected.These species could be classifi ed into six groups on the basis of temporal distribution patterns.The resident crab Ovalipes punctatus dominated the community,both in number and biomass.A clear seasonal succession was observed in the species composition.Cluster analysis revealed three primary seasonal groups corresponding to the samples collected in winter-spring,late spring-summer and late summer-autumn.The highest biomass and lowest diversity were observed in summer,while the lowest biomass and highest diversity in winter.The abundance-biomass comparison curves and community composition suggested that the investigated community was moderately disturbed.The results suggest that reduction in fi shing pressure and in the degree of seasonal hypoxia are essential for sustainable resource management off the Changjiang River estuary.

泛在学习:构筑学生数学学习无界时空

“泛在学习”是数字化学习浪潮中的一种全新学习范式,是一种“无时不在”“无处不在”的学习范式。作为教师,要发掘“泛在学习”资源,扩大“泛在学习”伙伴,做好“泛在学习”服务。通过创设无界的数学学习平台,生发无界的数学学习话题,呈现无界的数学学习界面,构筑学生数学学习的无界时空。

Comparisons of three data storage models in parametric temporal databases

The parametric temporal data model captures a real world entity in a single tuple, which reduces query language complexity. Such a data model, however, is difficult to be implemented on top of conventional databases because of its unfixed attribute sizes. XML is a matured technology and can be an elegant solution for such challenge. Representing data in XML trigger a question about storage efficiency. The goal of this work is to provide a straightforward answer to such a question. To this end, we compare three different storage models for the parametric temporal data model and show that XML is not worse than any other approaches. Furthermore, XML outperforms the other storages under certain conditions. Therefore, our simulation results provide a positive indication that the myth about XML is not true in the parametric temporal data model.

A Spatio-Temporal Odyssey Around the Concepts of Sustainable Development and Corporate Social Responsibility： Boundaries to Be Determined？

The aim of this research is to analyze the emergence of the concepts of sustainable development （SD） and corporate social responsibility （CSR） in companies in time and space. A spatio-temporal reading will indicate the most important socio-political and environmental events that have emerged with these two concepts. In order to complete the odyssey, a spatio-temporal analysis has retraced the epistemological evolution of these latter, whilst at the same time remarking the appropriation that has been made by the different institutional and organizational actors. The historical and epistemological reviews tell us that these two concepts, which came into existence almost 80 years, have indefinite outlines; one can be substituted for the other. However, thanks to this odyssey, we have reduced the boundaries even further between sustainable development and social responsibility and shown their theoretic and historical association. The perspective adopted shows that the concept of corporate social responsibility is closely connected to that of sustainable development. This connection means that researchers in management science are faced with more new problem issues reaching further than the simple lack of conceptual consensuses.

Generalized Dirichlet Normal Ordering in Open Bosonic Strings

Generally, open string boundary conditions play a nontrivial role in string theory. For example, in the presence of an antisymmetric tensor background field, they will lead the spacetime coordinates noncommutative. In this paper, we mainly discuss how to build up a generalized Dirichlet normal ordered product of open bosonic string embedding operators that satisfies both the equations of motion and the generalized Dirichlet boundary conditions at the quantum level in the presence of an antisymmetric background field, as the generalized Neumann case has already been discussed in the literature. Further, we also give a brief check of the consistency of the theory under the newly introduced normal ordering.

The space time CE/SE method for solving one-dimensional batch crystallization model with fines dissolution

This article is concerned with the numerical investigation of one-dimensional population balance models for batch crystallization process with fines dissolution.In batch crystallization,dissolution of smaller unwanted nuclei below some critical size is of vital importance as it improves the quality of product.The crystal growth rates for both size-independent and size-dependent cases are considered.A delay in recycle pipe is also included in the model.The space–time conservation element and solution element method,originally derived for non-reacting flows,is used to solve the model.This scheme has already been applied to a range of PDEs,mainly in the area of fluid mechanics.The numerical results are compared with those obtained from the Koren scheme,showing that the proposed scheme is more efficient.

Spatial and Temporal Analysis of Carbon Sequestrations in the Conterminous United States

This study develops geospatial analysis of terrestrial carbon exchange for the conterminous United State and estimates large-scale NEP （net ecosystem production） dynamic from 2008 to 2013. We apply land-use and land-cover data in order to coherently include cropland, forest, wetland and other ecologically active landscapes in the mapping. Our results show a distribution of high harvest carbon release in the Corn Belt states, in addition to hot spots around the US in areas like Southern California and Arizona. Harvest carbon is low in areas in the southern United States, and central/southern Appalachian Mountains. We identify NEP changes for coupled agricultural, forest and other high-carbon-uptake ecosystems systems, conversions to and from crop, and land in frequent conversion among forest, wetland, pasture and rangeland. Findings from this study will provide important information to support and promote the co-production of science and decision-making.

Spatio-temporal variation and the driving forces of tea production in China over the last 30 years

As a daily necessity and an important cash crop in China and many other countries, tea has received increasing attention. Using production concentration index model and in- dustry＇ s barycenter theory, we analyzed the spatio-temporal distribution of tea production and barycenter movement trajectory of tea plantations and production in China between 1986 and 2015. Driving forces of the movement were also analyzed. From 1986 to 2000, tea production in China＇s Mainland of grew slowly （by 210x103 t）. The continuous increase in tea yield per unit area was the primary contributor （more than 60%） to the growth in tea production during this period. Since China joined the World Trade Organization （WTO） in 2001, tea production has grown rapidly, by 1.59x106 t between 2001 and 2015. The increase in the tea plantations area is the main contributor. Over the last 30 years, the barycenters of tea production in China have moved westward from the Dongting Lake Plain to the eastern fringe of the Yun- nan-Guizhou Plateau. Guizhou, Guangxi, and Sichuan in southwestern China have gradually become regions of new concentrated tea plantations and main tea production provinces. Lower cost of land and labor in southwestern China are the main drivers of the westward movement of China＇s tea industry. In addition, supportive policies and the favorable natural geographical environment contribute to the westward movement of tea industry. Our research highlights the spatio-temporal variation of China＇s tea production in the last three decades. The result indicates importance to make appropriate policies to promote the development of tea industry in China.

Thermodynamics of the Reissner-Nordstrm-de Sitter black hole

Considering the relationship between the black hole horizon and the cosmological horizon, the thermodynamic property of the charged de Sitter spacetime is discussed. The effective temperature and energy are obtained. The result shows that the upper limit of the energy in the charged de Sitter spacetime is just the energy in the pure de Sitter spacetime. The thermal capacity of the charged de Sitter spacetime is positive, thus satisfying the thermal stability condition.

Lagrangian-based spatial-temporal topological study on the evolution and migration of coherent structures in wall turbulence

In this work,we study the development,evolution,and migration of turbulent coherent structures in the turbulent boundary layer at Reτ=630 using time-resolved particle image velocimetry(TR-PIV).Multiple techniques,including multi-scale analysis,conditional averaging,cross-correlation,and spatial-temporal topological analysis are applied to extract the evolution principle,migration trajectory,and convection velocity vector of the targeted coherent structures from a Lagrangian perspective.The spanwise vortex structures with larger scale and intensity at a certain wall-normal height y were the main focus of the present study.In the statistical sense,spanwise vortex structures move away from the wall with the shape changing from a bulge to an ellipse,and finally to a circle.Two straight lines emerge from the mean transfer trajectory curve of the spanwise vortex,in which the horizontal one is located at the viscous sublayer(y^(+)<10),the other is a logarithmic straight line existing in the range of 50<y^(+)<120,and the inclination angle of the tangential migration path is fixed at around 12°.The streamwise convection velocity U_(c)of scaled spanwise vortex structures satisfies U_(c)/U_(∞)=0.5-0.6 below y=0.03δ(i.e.,U^(+)_(c)=11-13 undery^(+)=20).In particular,in the region of 50<y^(+)<120,the velocity growth curves of U_(c)and wall-normal convection velocity V_(c)follow the log-law distribution very well,and the slopes are consistent with that of the log-law region of the turbulent boundary layer.Our observations provide microscopic evidences of the logarithmic-linear distribution of the migration trajectory of spanwise vortex structures.

On the Critical Behavior of Gapped Gravitational Collapse in Confined Spacetime

The gravitational collapse of a massless scalar with a cosmological constant A is investigated. The mass field enclosed with a perfectly reflecting wall in a spacetime scaling for the gapped collapse MAH -- Mg oc （ec -- e） is confirmed and a new time scaling for the gapped collapse Tall -- Tg c（ （ec - e）〈 is found. For both the critical exponents, we find strong evidence to show that they are non-universal. Especially when A ~ O, we find that both of these two critical exponents depend on the combination AR2, where R is the radial position of the reflecting wall. We find an evolution of the critical exponent from 0.37 in the confined asymptotic dS case with AR2 = 1.75 to 0.68 in the confined asymptotic AdS case with AR2 -- -1.75, while the critical exponent （ varies from 0.10 to 0.26, which shows that the new critical behavior for the gapped collapse is essentially different from the Choptuik＇s case.

A numerical study of a turbulent mixing layer and its generated noise

A direct numerical simulation of a turbulent mixing layer with the Reynolds number 500 and the convective Mach number 0.6 is performed and the results obtained are used to study the turbulent flow field and its generated noise.In the present simulation,the numerical techniques of absorbing buffer zones,artificial convection velocity and spatial filtering are used to achieve nonreflecting boundary conditions.The self-similarity is used to validate the present numerical simulations.The large-scale coherent structures are plotted together with the acoustic waves,which demonstrates the directivity of acoustic waves.The Lighthill's source and space-time correlations are further investigated.The main contributions to mixing noise are identified in terms of large-scale coherent structures,Lighthill's source and space-time correlations.

BIFURCATION AND SPATIOTEMPORAL PATTERNS IN A HOMOGENEOUS DIFFUSION-COMPETITION SYSTEM WITH DELAYS

A competitive LotkaVolterra reactiondiffusion system with two delays subject to Neumann boundary conditions is considered. It is well known that the positive con stant steady state of the system is globally asymptotically stable if the interspecies competition is weaker than the intraspecies one and is unstable if the interspecies com petition dominates over the intraspecies one. If the latter holds, then we show that Hopf bifurcation can occur as the parameters （delays） in the system cross some critical val ues. In particular, we prove that these Hopf bifurcations are all spatially homogeneous if the diffusive rates are suitably large, which has the same properties as Hopf bifur cation of the corresponding delayed system without diffusion. However, if the diffusive rates are suitably small, then the system generates the spatially nonhomogeneous Hopf bifurcation. Furthermore, we derive conditions for determining the direction of spatially nonhomogeneous Hopf bifurcations and the stability of bifurcating periodic solutions. These results indicate that the diffusion plays an important role for deriving the complex spatiotemporal dynamics.

Collapse of Self-Interacting Scalar Field in Anti-de Sitter Space

The gravitational collapse of a massless scalar field with a self-interaction term λφ~4 in anti-de Sitter space is investigated.We numerically investigate the effect of the self-interaction term on the critical amplitudes,forming time of apparent horizon,stable island,and energy transformation.The results show that a positiveλsuppresses the formation of black hole,while a negativeλenhances the process.We define two susceptibilities to characterize the effect of the self-interaction on the black hole formation,and find that near the critical amplitude,there exists a universal scaling relation with the critical exponentα≈0.74 for the time of black hole formation.

Existence of spatiotemporal patterns in the reaction-diffusion predator-prey model incorporating prey refuge

The pattern formation in reaction-diffusion system has long been the subject of interest to the researchers in the domain of mathematical ecology because of its universal exis- tence and importance. The present investigation deals with a spatial dynamics of the Beddington-DeAngelis predator-prey model in the presence of a constant proportion of prey refuge. The model system representing boundary value problem under study is subjected to homogeneous Neumann boundary conditions. The asymptotic stability including the local and the global stability and the bifurcation as well of the unique pos- itive homogeneous steady state of the corresponding temporal model has been analyzed. The Turing instability region in two-parameter space and the condition of diffusion- driven instability of the spatiotemporal model are investigated. Based on the appro- priate numerical simulations, the present model dynamics in Turing space appears to get influenced by prey refuge while it exhibits diffusion-controlled pattern formation growth to spots, stripe-spot mixtures, labyrinthine, stripe-hole mixtures and holes repli- cation. The results obtained appear to enrich the findings of the model system under consideration.