新型拖拉机电液控制系统

对具有锥阀式结构的电液控制系统在操作平顺性、液压冲击、发热、卸荷压力、响应特性等方面进行了详细的研究,提出利用动压反馈装置解决冲击问题。在本文所述条件下,农具提升时所引起的拖拉机俯仰角速度由原来拖拉机液压系统的0.3 rad/s降到0.08 rad/s,压力冲击峰值由4.0 MPa降到2.8 MPa,卸荷时控制阀块内部压力损失为0.12 MPa,达到热平衡时的液压油温度为38℃,该电液控制系统的开关频率为5.5 Hz。     

Magnetic bead manipulation in a sub-microliter fluid volume applicable for biosensing

Magnetic actuation principles using superparamagnetic beads suspended in a fluid are studied in this paper. An experimental setup containing a sub-microliter fluid volume surrounded by four miniaturized electromagnets was designed and fabricated. On the basis of optical velocity measurements, the induced behavior of single beads and ordered chains was analyzed and compared to a theoretical model. This research can be used to develop new techniques for accelerated transportation in lab-on-a-chip bio-assays.     

眼底成像处理系统的研究

介绍了一种新型眼底成像装置及相关图像处理系统．该仪器可广泛用于多种脉络膜及眼底疾病的临床诊断和研究工作．     

Algorithms for Sensorless Manipulation Using a Vibrating Surface

We describe a programmable apparatus that uses a vibrating surface for sensorless, nonprehensile manipulation, where parts are systematically positioned and oriented without sensor feedback or force closure. The idea is to generate and change the dynamic modes of a vibrating surface. Depending on the node shapes of the surface, the position and orientation of the parts can be predicted and constrained. The vibrating surface creates a two-dimensional force vector field. By chaining together sequences of force fields, the equilibrium states of a part in the field can be successively reduced to obtain a desired final state. We describe efficient polynomial-time algorithms that generate sequences of force fields for sensorless positioning and orienting of planar parts, and we show that these strategies are complete. Finally we consider parts feeders that can only implement a finite set of force fields. We show how to plan and execute strategies for these devices. We give numerical examples and experiments. and discuss tradeoffs between mechanical complexity and planning complexity. Received November 15, 1996; revised January 18, 1998.     

水文遥测系统应用软件中的数据流对象化探讨

不同版本的水文遥测系统中用到的通讯及网络数据流形式复杂多样,系统通用性及可扩展性不强,实时性低,信息兼容集成成本高。在简单分析水文遥测系统存在问题的基础上,详细探讨了将已建的水文遥测系统应用软件中的数据流对象化封装,即通讯及网络协议对象化的封装,定制使用,提高了系统的兼容复用性。     

裙装造型规律及其CAD方法的研究

本文通过分析基本裙型的“省移变款”的规律，揭示了典型裙装纸样的设计原理、规律和技巧，并通过服装ＣＡＤ技术，实现了典型裙装的计算机辅助设计，从而降低了纸样的设计难度，缩短了设计周期．     

Time-evolving rule-based knowledge bases

Human knowledge in any expertise area changes with respect to time. Two types of such knowledge can be identified, time independent and time dependent. It is shown that the maintenance effort of the latter is harder than that of the former. The present paper applies research results in the area of temporal databases, in order to maintain a rule-based knowledge base whose content changes with respect to the real world time. It is shown that the approach simplifies the maintenance of time dependent knowledge. It also enables the study of the evolution of knowledge with respect to time, which is knowledge on its own. Three distinct solutions are actually proposed and evaluated. Their common characteristic is that knowledge is stored in a database; therefore, all the advantages of databases are inherited by knowledge bases. Implementations are also reported.     

微型汽车离合器分离拨叉螺母调整的研究

微型汽车离合器在使用一段时间以后,由于摩擦片磨损的原自,其操纵机构自由间隙和自由行程会发生改变,不合理的间隙和行程是影响离合器从动盘摩擦片早期磨损的主要因素之一,目前,只能通过经验和主观臆断来调节分离拨叉软管上的螺母使得自由间隙和行程重新达到设计的要求,由于没有理论依据经常会由于来回调节次数过多,造成人员疲惫,针对这一情况,依靠自由间隙,传动比,传动效率以及自由行程之间的相互约束,提出了一种通过计算的方法来确定调整螺母旋转圈数的方案,从而使得螺母旋转圈数、自由行程、自由间隙之间的关系有一个清晰的理论依据,并为今后优化离合器操纵机构的性能奠定了理论基础。     

The Horace Brown Medal Lecture: Forty Years of Brewing Research

Horace Brown spent fifty years conducting brewing research in Burton‐on‐Trent, Dublin and London. His contributions were remarkable and his focus was to solve practical brewing problems by employing and developing fundamental scientific principles. He studied all aspects of the brewing process including raw materials, wort preparation, fermentation, yeast and beer stability. As a number of previous presenters of the Horace Brown Lecture have discussed Brown's achievements in detail, the focus of this paper is a review of the brewing research that has been conducted by the author and his colleagues during the past forty years. Similar to Horace Brown, fundamental research has been employed to solve brewing problems. Research studies that are discussed in this review paper include reasons for premature flocculation of ale strains resulting in wort underattenuation including mechanisms of co‐flocculation and pure strain flocculation, storage procedures for yeast cultures prior to propagation, studies on the genetic manipulation of brewer's yeast strains with an emphasis on the FLO1 gene, spheroplast fusion and the respiratory deficient (petite) mutation, the uptake and metabolism of wort sugars and amino acids, the influence of wort density on fermentation characteristics and beer flavour and stability, and finally, the contribution that high gravity brewing has on brewing capacity, fermentation efficiency and beer quality and stability.     

特征模型直接操作技术的研究

目前的语义特征造型系统,由于约束求解的速度比较缓慢,还不能支持直接操作的特性。利用特征依赖图的数据模型来保存和维护特征的信息及其之间的依赖关系,并且提出了约束操作算法和特征操作算法,将特征的操作局限在模型的特定区域内。该方法最大限度地减少了所需要求解的约束数目,满足了直接操作过程中对约束求解速度的要求,从而实现了对特征的直接操作。