冰心儿童文学研究的趋向

20世纪80年代以来的冰心儿童文学研究,主要集中在对冰心儿童文学中的儿童形象、作为＂爱＂的歌者的冰心对母爱、童心和自然的歌颂,以及冰心儿童文学的艺术魅力这三个方面,对近30年来的冰心儿童文学研究进行梳理,可找出新时期以来冰心儿童文学研究的轨迹和趋向。     

3.5 GHz WiMAX射频功率放大器的实现及其预失真模型

针对IEEE802.16e WiMAX标准设计并实现了中心频率为3.5GHz、峰值功率为10W的LDMOS大功率射频功率放大器.采用负载牵引法确定了功放管的最佳输入和输出阻抗.各项指标的仿真结果与实测结果高度吻合.提出一种低记忆功放并结合间接学习的方法,对该功放进行行为级建模和数字预失真,同时建立了多载波信号产生和采集的软硬件平台.实验结果表明,对于三载波W-CDMA宽带输入信号,当输出平均功率为30dBm时,采用仅7个系数的Hammerstein模型,即可得到-47.5dBc的邻道泄漏(ACLR)指标,改善度达到14dB.相对于传统的预失真技术,提出的方法能够在保证预失真性能的同时减少计算量,具有良好的应用前景.     

Pricing barrier options under stochastic volatility framework

Option pricing problem plays an extremely important role in quantitative finance. In complete market, Black-Scholes-Merton theory has been central to the development of financial engineering as both discipline and profession. However, in incomplete market, there are not any replicating portfolios for those options, and thus, the market traders cannot apply the law of one price for obtaining a unique solution. Fortunately, the authors can get a fair price via local-equilibrium principle. In this paper, the authors apply the stochastic control theory to price the exotic option-barrier options, and analyze the relationship between the price and the current positions. The authors get the explicit expression for the market price of the risk. The position effect plays a significant role in option pricing, because it can tell the trader how many and which direction to trade with the market in order to reach the local equilibrium with the market.     

超声波对锂离子正极材料LiCoO2性能的影响

在电解法的基础上,提出了一种新的改进方法来制备锂离子电池正极材料.经超声波与相转移后,采用电解液中析出的Li2CO3和电解中间产物Co(OH)2作为前驱物制备得到了锂离子正极材料LiCoO2.通过X射线衍射,扫描电镜对所合成的材料进行了表征.实验结果证明,该前驱物在850℃下反应仅3h就能得到性能优异的LiCoO2正极材料,大大缩短了反应时间.     

一个自治系统的混沌控制与同步

对一个新三维混沌自治系统进行研究.根据线性负反馈法和Routh-Hurwitz稳定性条件,得到达到控制目标时负反馈系数所满足的条件.根据Lyapunov稳定性定理,利用Lyapunov直接法在响应系统中构造非线性函数,实现了该系统的完全同步,并证明了该系统同步误差的零点稳定性.最后利用Matlab进行数值仿真,结果表明该方法是可行的、有效的.     

P-集合与隐形图像生成-还原

P-集合是把动态特性引入到有限普通集合中,改进普通集合得到的,P-集合(XF,XF)是一个集合对.利用P-集合生成的图像,提出P-隐形图像的概念,给出P-隐形图像的属性特征和度量特征,提出P-隐形图像生成-还原定理,并给出了P-隐形图像在图像信息系统中的应用.     

基于TMS320C5509的UC/OS-Ⅱ移植研究

在深入了解UC/OS-Ⅱ内核架构的基础上,对嵌入式实时操作系统UC/OS-Ⅱ移植到TI公司TMS320C5509上进行了研究,并以此形成基于DSP的嵌入式实时系统平台.主要讨论了移植的可行性,流程和移植过程中的一些关键问题,如堆栈,任务切换,编写中断函数等.最后对移植后系统进行测试,测试结果表明移植成功,对解决此类问题...     

Periodical oscillating interface in directional growth under shear flow

Liquid-solid interface morphological evolution of SCN-2wt%H2O alloy was investigated in the presence of shear flow. It has been found that shear flow strikingly enhances the stability of planar interface at lower pulling rates. In the intermediate range of pulling rate, the interface experiences periodical oscillating ＂planar-cellular＂ and ＂cellular-dendritic＂ growth patterns. The formation of oscillating growth modes can be explained by two reasons： （i） The stabilizing effect induced by shear flow competes with the growing destabilizing effect by the increase of pulling rate, which provides the driving force for morphological evolution; and （ii） the establishment of stable solute field at the liquid-solid interface needs a period of time, leading to the result that the interface evolution can not stay stable at the equilibrium state. However, as the puling rate becomes higher, it plays more and more important roles in pattern selection and dendritic growth forms.     

Solar-driven high temperature radiant cooling

Solar energy is widely used as one of the most important renewable energy. In addition to the growing applications of solar PV and solar water heater, solar cooling is also considered very valuable and the related researches are developing fast because of the synchronism between solar irradiance and building cooling load. Current studies mainly focus on the high temperature solar collector technique and heat-driven cooling technique, while little concern has been paid to the transport process of cooling power. In this paper, the high temperature radiant cooling is studied as an alternative way for transporting cooling power, and the performance of the combination of radiant ceiling and solar cooling is also studied. From simulation and theoretical analysis results, high temperature radiant cooling terminal shows better cooling power transportation ability against conventional air-conditioning terminal, and its thermal comfort is improved. Experiment results indicate that radiant cooling can enhance the chiller’s COP (Coefficient of Performance) by 17% and cooling power regeneration by 50%. According to analysis in this paper, high temperature radiant cooling is proved to be suitable for solar cooling system, and out work can serve as a reference for later system design and promotion. Supported by the National Natural Science Foundation of China (Grant No. 50876064)     

基于数据流优化的BPEL流程分割方法

BPEL描述的业务流程在跨组织的企业应用集成与协作中扮演着重要角色.目前BPEL流程主要采用集中式的执行方式,但是集中式执行的BPEL流程性能不高并且不能满足动态流程管理的需求.提出了一种基于数据流优化的BPEL流程分割方法,以支持BPEL流程的分散化执行.BPEL流程经过变换被表示成PFG图,提出数据流方程对PFG图进行数据流分析,扩展复制传播算法优化PFG图的数据流.最后按照流程中的角色分割BPEL流程.实验数据表明优化分割后的业务流程的吞吐率、响应时间等方面的性能有较大提高.