Real-time studies on microalgae under microgravity

Using remote sensing technique, we investigated real-time Nostoc sphaeroides Kiltz (Cyanobacterium) in Closed System under microgravity by SHENZHOU-2 spacecraft in January 2001. The experiments had 1g centrifuges in space for control and ground control group experiments were also carried out in the same equipments and under the same controlled condition. The data about the population growth of Nostoc sp. of experiments and temperature changes of system were got from spacecraft every minute. From the data, we can find that population growth of Nostoc sp. in microgravity group was higher than that of other groups in space or on ground, even though both the control I g group in space and I g group on ground indicated same increasing characteristics in experiments. The growth rate of 1.4g group (centrifuged group on ground) was also promoted during experiment. The temperature changes of systems are also affected by gravity and light. Some aspects about those differences were discussed. From the discussion of these results during experiment, it can be found that gravity is the major factor to lead to these changes. (C) 2004 Elsevier Ltd. All rights reserved.

A programmable SIMD vision chip for real-time vision applications

A programmable vision chip for real-time vision applications is presented. The chip architecture is a combination of a SIMD processing element array and row-parallel processors, which can perform pixel-parallel and row-parallel operations at high speed. It implements the mathematical morphology method to carry out low-level and mid-level image processing and sends out image features for high-level image processing without I/O bottleneck. The chip can perform many algorithms through software control. The simulated maximum frequency of the vision chip is 300 MHz with 16 x 16 pixels resolution. It achieves the rate of 1000 frames per second in real-time vision. A prototype chip with a 16 x 16 PE array is fabricated by the 0.18 mu m standard CMOS process. It has a pixel size of 30 mu m x 40 mu m and 8.72 mW power consumption with a 1.8 V power supply. Experiments including the mathematical morphology method and target tracking application demonstrated that the chip is fully functional and can be applied in real-time vision applications.

Investigation of the polyetherketone guest-host DR1/PEK-c polymer films by real-time monitoring of the second-harmonic generation

The real-time monitoring of the second-harmonic generation (SHG) was used to optimize the poling condition and to study the nonlinear optical (NLO) properties of the polyetherketone (PEK-c) guest-host polymer films. The high second-order NLO coefficient chi(33)((2)) = 11.02 pm/v measured at 1.064 mu m was achieved when the weight percent of DR1 guest in the polymer system is 20%. The NLO activity of the poled DR1/PEK-c polymer film can maintain more than 80% of its initial value when temperature is under 100 degrees C, and the normalized second-order NLO coefficient can maintain more than 85% after 2400 s at 80 degrees C. (C) 2000 Elsevier Science Ltd. All rights reserved.

a real-time path planning approach without the computation of cspace obstacles

An important concept proposed in the early stage of robot path planning field is the shrinking of the robot to a point and meanwhile expanding of the obstacles in the workspace as a set of new obstacles. The resulting grown obstacles are called the Configuration Space (Cspace) obstacles. The find-path problem is then transformed into that of finding a collision free path for a point robot among the Cspace obstacles. However, the research experiences obtained so far have shown that the calculation of the Cspace obstacles is very hard work when the following situations occur: 1. both the robot and obstacles are not polygons and 2. the robot is allowed to rotate. This situation is even worse when the robot and obstacles are three dimensional (3D) objects with various shapes. Obviously a direct path planning approach without the calculation of the Cspace obstacles is strongly needed. This paper presents such a new real-time robot path planning approach which, to the best of our knowledge, is the first one in the robotic community. The fundamental ideas are the utilization of inequality and optimization technique. Simulation results have been presented to show its merits.

Real-Time SQL的设计与实现

实时数据库的结构化查询语言RTSQL(Real-Time SQL)是实时数据库研究的一项重要内容.论文详细论述了RTSQL的一种设计方法,即扩展SQL92标准以支持实时数据库的要求,构建RTSQL语言的方法.文章还介绍了RTSQL在Agilor实时数据库系统中的实现方式.在文章最后给出了RTSQL进一步研究的思路和建议。

Real-time non-destructive testing of dynamic holograms in doubly-doped LiNbO3 crystals using phase-conjugate technique

Nankai University

Real-time far distance micro-vibration measurement using an external cavity semiconductor laser interferometer with a feedback control system

An external cavity semiconductor laser interferometer used to measure far distance micro-vibration in real time is proposed. In the interferometer, a single longitudinal mode and excellent coherent characteristic grating external cavity semiconductor laser is constructed and acted as a light source and a phase compensator. Its coherent length exceeds 200 meters. The angle between normal and incidence beam of the far object is allowed to change in definite range during the measurement with this interferometer, and this makes the far distance interference measurement easier and more convenient. Also, it is not required to keep the amplitudes of the first and second harmonic components equal, and then the dynamic range is increased. A feedback control system is used to compensate the phase disturbance between the two interference beams introduced by environmental vibration.