临界模式下的单级功率因数校正电路及储能电容电压控制的研究

本文首先分析了单级功率因数校正(PFC)电路中的电流畸变特性,然后对PFC变换器及DC DC变换器工作在连续及不连续的边界条件进行了讨论,得出了电路工作状态的精确解。在此基础上,本文提出了一种全新的临界工作模式下的单级功率因数校正电路,阐明了控制储能电容电压的临界点工作方式。该电路在利用普通控制芯片实现较高功率因数的同时,有效地控制了储能电容的电压值,降低了开关应力,提高了电路的效率。实验验证了本文数学推导的正确性和控制策略的实用性。     

组件模型(CCM)的多视点分析

中间件与组件相结合正成为分布式系统开发的一个主要方向。CORBA是一个主流的中间件,最新的CORBA3.0规范增加CORBA组件模型(CCM),完成了CORBA向“组件化”转化的目标。文章分析了CCM产生的原因和背景,并运用IEEEStd1471多视点的分析方法,较全面的从各个视点剖析了CORBA组件模型,并给出了CCM的一个完整的多视点视图和基于CORBA组件的软件开发过程。最后指出了CCM需要进一步研究和完善的地方。     

梅钢炼钢350万t配套连铸机建设方案讨论

为适应梅钢350万t钢的生产规模,同时满足面向冷轧产品的结构优化的需要,需对制约环节炼钢系统进行配套建设,其中包括新增1流连铸设备,基于现有工艺设备条件,配套建设目标等,对新增连铸设备的工程技术方案进行讨论,分析生产模式,技术装备组成,以期形成最佳技术方案.     

板坯连铸机自动控制及跟踪系统的开发

简要介绍济钢一炼钢5#板坯连铸机自动控制及自动跟踪系统的研究、开发及应用,由此带来的浇铸节奏大大提高,工人的劳动强度大大降低.     

中间包定径水口在线快速更换技术在连铸机上的应用

介绍韶钢炼轧厂中间包定径水口快速在线更换技术的应用、效果及其存在的问题．     

大型板坯连铸控制系统

本文结合某钢厂大型板坯连铸机的设计,重点途径了在引进“二手”板坯连铸设备的基础上,配置全新“三电”控制系统的功能。     

CCM构件技术的研究与实现

本文首先介绍CCM产生的背景和驱动力,然后介绍我们参照CCM规范实现的CCM构件平台。最后,通过比较构件模型和对象模型及比较两种构件模型CCM和EJB,对CCM构件技术的特点进行了总结。     

Chitin and chitosan in selected biomedical applications

Chitin (CT), the well-known natural biopolymer and chitosan (CS) (bio-based or “artificial polymer”) are non-toxic, biodegradable and biocompatible in nature. The advantages of these biomaterials are such that, they can be easily processed into different forms such as membranes, sponges, gels, scaffolds, microparticles, nanoparticles and nanofibers for a variety of biomedical applications such as drug delivery, gene therapy, tissue engineering and wound healing. Present review focuses on the diverse applications of CT and CS membranes and scaffolds for drug delivery, tissue engineering and targeted regenerative medicine. The chitinous scaffolds of marine sponges’ origin are discussed here for the first time. These CT based scaffolds obtained from Porifera possess remarkable and unique properties such as hydration, interconnected channels and diverse structural architecture. This review will provide a brief overview of CT and CS membranes and scaffolds toward different kinds of delivery applications such as anticancer drug delivery, osteogenic drug delivery, and growth factor delivery, because of their inimitable release behavior, degradation profile, mucoadhesive nature, etc. The review also provides an overview of the key features of CT and CS membranes and scaffolds such as their biodegradability, cytocompatibility and mechanical properties toward applications in tissue engineering and wound healing.     

Generalizing intersection kernel support vector machines for color texture based recognition

This paper presents a novel recognition approach in which the component-adaptive color co-occurrence matrices (CACCMs) are designed to characterize color and texture cues in the images, while histogram intersection kernel support vector machines (HIKSVMs) are generalized to the version compatible to color co-occurrence matrix (CCM), called CCM intersection kernel support vector machines (CIKSVMs). An ensemble learning framework is proposed for synchronously training the optimal marginal CIKSVMs and corresponding CACCMs’ extractors. This learning architecture is applicable to an arbitrary color space employed for image coding, while we pay utmost attention to a perceptual uniform color space for the prominent potential in image proprieties’ display. For the formulation of recognition algorithm, the set of multi-channel CACCMs (CAMCMs) of per sample is utilized to get a balance between discriminative power and computational efficiency, while multiple marginal CIKSVMs are combined by weighted majority voting. The effectiveness of our approach is validated by promising results obtained from four experimental datasets.     

LED低压驱动电源——DC/DC降压-升压变换器（上）

详细叙述了DC/DC降压-升压变换器LED驱动电路的演变及工作原理,推导了此类电路输出电压与输入电压的关系,并以占空比D表示;介绍了两种典型芯片及其实际使用中的有关知识。