数字水印演化设计

数字水印算法中相关参数的选择是水印算法设计的一个关键问题。不同的参数选取，将直接影响到算法的有效性。该文给出一种采用演化计算进行水印参数有效选择的方法，实验结果表明，这种方法在提高水印健壮性的同时保证保真度。     

噪声环境下语音识别方法的研究

1引言 语音识别的性能常常与环境背景噪声等的干扰有密切关系A[1],这些都是语音识别的识别率得不到进一步提高的主要因素.     

一种基于CORBA的分布式全文检索系统设计

海量信息的全文检索是人类获取信息的重要手段之一,而网络海量信息的检索使传统的全文检索技术面临新的挑战。如何改善检索系统的结构,提高检索系统的性能和效率,以加快检索速度,成为一个值得研究的课题。公用对象请求代理体系CORBA技术的出现为这一课题提供了一个有效的解决方法。该文在对WEB计算方式和CORBA体系进行详细讨论的基础上,结合实际课题的研究,给出了一种基于CORBA技术的分布式全文检索系统架构设计。     

直流PWM伺服系统的一种新型控制器

文章设计了一种新型的直流PWM自适应变结构控制器，并且采用了非线性反馈技术，理论分析与实验表明该系统获得良好的快速性、准确性和鲁棒性。     

葫芦岛蒙脱土的特征与催化活性

研究了葫芦岛蒙脱土的某些特征与催化活性。该蒙脱石的离子交换能力与层间距分别是７５ｍｅｑ／１００ｇ和１．５２９ｎｍ，对偏三甲苯的歧化、异构化以及偏四甲苯的脱甲基、异构化都具有催化活性。这些数据表明葫芦岛蒙脱土是一种有用的催化材料。     

Microstructure evolution during reheating of a Nb-bearing steel I. Metallographic examination

Cooled in water after the isothermal relaxation of deformed austenite for different timea, a Nb-bearing microalloyed steel always exhibits synthetic microstructures of bainitic ferrite, granular bainite and acicular ferrite. When these samples were reheated to and held at 650 or 700℃, the non-equilibrious microstructures tend to evolve into equilibrious ones. The sample relaxed for 60 s displays the highest thermostability, while the microstructure evolution is the quickest in the sample relaxed for 1000 s even though it is the softest before reheating. Softening is not a single process occurring during reheating, in which the hardness fluctuates with time. There are two peaks in the hardness-time curve of each sample having undergone relaxation, while a single peak occurs in the curve of the sample having not been relaxed. Pre-strain accelerates the evolution process. These results indicate that the thermostability of microstructures is determined by their history of formation to a considerable degree.     

铝复合变质处理对M_2铸造高速钢的影响

Ｍ２铸造高速钢加铝复合变质处理后，可减小Ｗ，Ｍｏ元素偏析，加大Ｃｒ元素偏析，改善铸态与热处理后组织中共晶碳化物的形态和分布，提高机械性能。     

Preparation and structure of fluorinated/non-fluorinated polyacrylate gradient emulsion blend film

The emulsion blend method, which is environmentally friendly and energy saving, was used to prepare a compositional gradient film of fluorinated/non-fluorinated polyacrylate in this paper. The size and glass-transition temperature (T_g) of the emulsion particles were designed to enhance the driving force of their selective congregation and promote the formation of gradient structure. The structures and surface properties of the obtained films were characterized. The results showed that when the fluorinated components have much smaller particle size and higher T_g than those of fluorine-free polyacrylate components, the gradient structures formed in the direction across the film thickness of the films. The concentration of the fluorinated component increased gradually from film-glass interface to film-air interface in the blend film, making the surface free energies of the two sides of the gradient film distinctively different.     

Studied on a novel human keratinocyte membrane delivery system in vitro

The culture of keratinocytes on flexible membranes has been proposed as a means to simplify, accelerate and improve the efficiency with which proliferating cells are delivered to full thickness or non-healing skin defects. The purpose of this article was to study the ability of chitosan-gelatin manbranes to facilitate the growth of human keratinocytes. The membranes with different chitosan contents were studied. The surface properties of chitosan-gelatin membranes were investigate by SEM, and water contact angle test. The mechanical property of the membranes was tested. Data implied that gelatin could make the membranes more flexible and hydrophilic than chitosan membranes, which may regulate the seeded cells behavior. Loading human keratinocytes on chitosan-gelatin membranes, cells attachment, spread, and growth were investigated by light microscopy, SEM, and MTT test. The results suggested that the adhesion and proliferation of keratinocytes seeded on chitosan-gelatin membranes were same as on tissue culture plate, in which gelatin could modify the interaction between keratinocytes and chitosan membranes. Therefore, chitosan-gelatin membrane is a good candidate for keratinocytes delivery system.     

Kam-Fai Wong, Wenjie Li, Ruifeng Xu and Zheng-sheng Zhang: Introduction to Chinese natural language processing

This is a review of a recent book “Introduction to Chinese Natural Language Processing” by Kam-Fai Wong, Wenjie Li, Ruifeng Xu and Zheng-sheng Zhang. The structure and contents of the book will be briefly described and some comments and observations are presented.