中外城市战略规划编制比较

对国内的广州，南京，杭州三大城市的战略规划编制进行了分析，并与西方一些发达国家的城市战略规划编制进行了比较．提出中外战略规划在编制内容、成果、期限等方面存在着相同点和不同点，提出研究中外战略规划对中国传统总体规划改革具有多方面的启发和指导意义．     

基于Copula函数的华南台风灾情重现期研究

利用1981-2014年华南台风灾情数据,选取受灾人口、农作物受灾面积和直接经济损失,应用Copula函数理论,计算灾情重现期,分析台风灾害的灾情.首先,借助Clayton Copula函数构造三变量的联合分布,计算单变量重现期、联合重现期及同现重现期,并求出该重现期下的设计值.计算结果表明联合重现期的设计值要优于单变量重现期和同现重现期的设计值．因此,选取联合重现期的设计值作为防灾标准的最优参考,并将联合重现期记为灾情重现期．然后,计算2015-2017年登陆华南台风灾害的灾情重现期,并对台风灾害的灾情进行分析．发现台风灾情重现期越长的台风造成的灾情越严重．最后,利用灾情重现期与致灾重现期对台风灾害的发生频率作综合性分析,可以为台风灾害的风险评估提供一种新思路．     

用改进的格点哈密顿量计算2+1维QCD 0++胶球质量

用改进的格点哈密顿量和截断本征方程法计算2＋1维QCD 0^ 胶球质量,结果显示较好的标度行为。     

基于演化博弈的制造企业服务创新扩散研究

制造企业服务化是我国实现制造强国的必经之路,本文以“中国制造2025”战略为背景,通过借鉴创新扩散和演化博弈理论,对社会系统中参与服务创新的相关主体进行分析,构建政府与企业之间演化博弈模型,结合并改进Bass经典创新扩散模型,探究政府规制行为对企业服务创新行为演化及扩散的影响,利用Matlab对复制动态方程和扩散模型进行数学推导和数值仿真分析。结果表明:当满足政府的社会总收益大于其调控成本和各项补贴总额且企业选择服务创新策略时收益的额外增加额大于其实际投入时,系统才会演化至政府调控且企业采纳服务创新的稳定状态;适当增加政府对企业的调控力度、投入补贴和税收补贴有助于推进服务创新在系统中的扩散,其中税收补贴的感知能力最强,投入补贴最弱;将抑制系数引入Bass创新扩散模型,构建互补型、竞争型和替代型三种服务创新的扩散模式,其中竞争型扩散符合中国现阶段市场规律,替代性扩散将成为未来制造企业的发展趋势。     

东南部欠发达地区县域城乡空间统筹发展的规划思考

随着国内区域经济联动的加强,产业布局的调整升级,以及大区域交通条件的改善,我国城市化经济已经进入了一个＂全球化-区域化＂的新发展时期.东南部欠发达地区的城市化、工业化发展面临着若干重大机遇.通过分析县域城乡空间发展存在的一般性问题和制约因素,提出：东南部欠发达地区的发展应以空间规划作为切入点,通过空间规划与行动集成,将城乡统筹概念落实到县域空间层面上,构建一个综合的发展战略与行动规划.     

Generalized Persistence of Entropy Weak Solutions for System of Hyperbolic Conservation Laws

Let u(t, x) be the solution to the Cauchy problem of a scalar conservation law in one space dimension. It is well known that even for smooth initial data the solution can become discontinuous in finite time and global entropy weak solution can best lie in the space of bounded total variations. It is impossible that the solutions belong to, for example, H¹ because by Sobolev embedding theorem H¹ functions are H¨older continuous. However, the author notes that from any point (t, x), he can draw a generalized characteristic downward which meets the initial axis at y = α(t, x). If he regards u as a function of (t, y), it indeed belongs to H¹ as a function of y if the initial data belongs to H¹ . He may call this generalized persistence (of high regularity) of the entropy weak solutions.The main purpose of this paper is to prove some kinds of generalized persistence (of high regularity) for the scalar and 2 × 2 Temple system of hyperbolic conservation laws in one space dimension.     

中国聚变工程实验堆大功率混合直流开关概念设计

中国聚变工程实验堆中的超导线圈失超保护开关要求的额定参数达到了10 kV/±100 kA,针对该运行参数提出了一种混合式直流开关。承担稳态通流的机械开关采用了三级触头结构,可以降低固态开关的通流时间。双向固态开关的阀串采用二极管桥与IGBT组合的形式,结温分析证明可以提高器件的流通电流限制,并对该基本单元拓扑进行了大电流开断实验,验证了该设计的可行性。     

Acoustic absorbers at low frequency based on split-tube metamaterials

The remarkable properties of acoustic metamaterials have attracted massive researches and applications, especially on low-frequency sound absorptions. Currently, most of the acoustic metamaterial absorbers employ resonances in plastic cavities, and their structural strengths are important in many circumstances, especially in harsh environment. However, studies of metamaterials including this point are very scarce. Here, we propose an acoustic metamaterial for low-frequency (<500 Hz) absorptions, composed of three nested square split tubes with inverted opening directions. The efficiency of the absorber is investigated both numerically and experimentally, and absorptions at the peeks are found to exceed 90% and the frequency can be effectively adjusted by tuning its geometric parameters. We further test its yield strength under compression and confirm its buckling behavior happens from the outmost layer. This tunable acoustic metamaterial with a fairly good mechanical strength may lead to broad applications in noise reduction.     

Assessing Earthquake Forecast Performance Based on b Value in Yunnan Province,China

Many studies have shown that b values tend to decrease prior to large earthquakes. To evaluate the forecast information in b value variations, we conduct a systematic assessment in Yunnan Province, China, where the seismicity is intense and moderate–large earthquakes occur frequently. The catalog in the past two decades is divided into four time periods (January 2000–December 2004, January 2005–December 2009, January 2010–December 2014, and January 2015–December 2019). The spatial b values are calculated for each 5-year span and then are used to forecast moderate-large earthquakes (M ≥ 5.0) in the subsequent period. As the fault systems in Yunnan Province are complex, to avoid possible biases in b value computation caused by different faulting regimes when using the grid search, the hierarchical space–time point-process models (HIST-PPM) proposed by Ogata are utilized to estimate spatial b values in this study. The forecast performance is tested by Molchan error diagram (MED) and the efficiency is quantified by probability gain (PG) and probability difference (PD). It is found that moderate–large earthquakes are more likely to occur in low b regions. The MED analysis shows that there is considerable precursory information in spatial b values and the forecast efficiency increases with magnitude in the Yunnan Province. These results suggest that the b value might be useful in middle- and long-term earthquake forecasts in the study area.     

First neutron Bragg-edge imaging experimental results at CSNS

The neutron Bragg-edge imaging is expected to be a new non-destructive energy-resolved neutron imaging technique for quantitatively two-dimensional or three-dimensional visualizing crystallographic information in a bulk material, which could be benefited from pulsed neutron source. Here we build a Bragg-edge imaging system on the General Purpose Powder Diffractometer at the China Spallation Neutron Source. The residual strain mapping of a bent Q235 ferrite steel sample has been achieved with a spectral resolution of 0.15% by the time-of-flight neutron Bragg-edge imaging on this system. The results show its great potential applications in materials science and engineering.