适用于时间分辨荧光免疫分析仪的激发光系统

设计了一种能产生高频脉冲光的激发光系统。光源利用特制的高压Xe灯,Xe灯电源设计了时间、能量控制电路,解决了高频脉冲光脉宽较大的问题,使Xe灯能产生稳定的高频短脉冲光,再加上特别设计的石英透镜组,本激发光系统可得到光谱线范围可选的、脉冲宽度54μs和紫外能量大于200μW的1kHz的脉冲光。

3种方法对上颌前牙早期脱矿病损诊断价值的比较

目的:比较定量光激发荧光(quantitative light-induced fluorescence,QLF)系统与数码照相、肉眼检查3种方法对上颌前牙早期脱矿病损的检出率。方法:对德阳市和资阳市300名12周岁中学生的1732颗上颌前牙清洁干燥后,肉眼检查是否存在上颌前牙早期脱矿病损,并拍摄QLF照片和数码照片进行分析。结果:经卡方检验得出,QLF系统对上颌前牙早期脱矿病损的检出率(24.08%)显著高于肉眼直接检查(20.61%)和数码照相(22.17%),其差异均有统计学意义(P<0.05)。结论:QLF系统是一种对早期脱矿病损较可靠、快速、安全、无损伤的诊断方法,值得推广使用。

MECHANISM OF CHANGE IN THE CATION INDUCED EXCITA TION ENERGY DISTRIBUTION BETWEEN PSⅡ AND PSⅠ IN THE CHLOROPLAST MEMBRANE FROM ZOSTERA MARINA *

The interrelations between thylakoid polypeptide components and Mg 2+ induced Chl a fluorescence and thylakoid surface charge changes were investigated in Zostera marina chloroplasts treated with Ca 2+ and trypsin. It was observed that:1. The increase of Mg 2+ induced PSⅡ fluorescence intensity was closely related to the decrease of Mg 2+ induced surface charge density of the thylakoid membrane in the normal chloroplast; 2. Removal of the 32~34 kD polypeptides of the thylakoid surface by Ca 2+ extraction of the chloroplast did not affect the Mg 2+ induced phenomena; 3. If the Ca 2+ treated chloroplast was further digested by trypsin to remove the 26 kD polypeptide of the membrane surface, the Mg 2+ induced phenomena disappeared completely. These results clearly indicated that the 26 kD polypeptide of thylakoid surface is the specific acting site of the cation that induced these two correlated phenomena in the chloroplast from Zostera marina. The mechanism on the regulating effect of the cation on excitation energy distribution between PSⅡ and PSⅠ was discussed.

Research of Confocal Laser Induced Fluorescence Detection System for Micro-fluidic Chip

The characteristics such as signal noise ratio（SNR） and sensitivity of the fluorescence detection system for micro-fluidic chip influence the performance of the whole system extremely. The confocal laser induced fluorescence detection system is presented. Based on the debugging of optical and circuit modules, the results of detecting the samples are given and analyzed theoretically, and the improved project is put forward.

The Latest Study of Gravitational Wave Communication System

Gravitational wave is a strain wave of space and this can be also generated by strong magnetic field. The principle of gravitational wave generation using the fluctuation in strain field induced by magnetic field is introduced. Using both foregoing gravitational wave generator and gravitational wave detector （i.e. laser interferometric gravitational wave antenna）, the gravitational communication system can be possible. This paper introduces its content presented at 20th Annual Lecture （1989） and the research trends in the latest gravitational wave.

Application of Tunable Diode Laser Absorption Spectroscopy with Optical Hollow Fiber to Engine Exhaust Gas Measurement

In recent years, tighter regulation has been already enforced on harmful substances such as NOx, CO, and particles. Considering the above situation, it is important to monitor controlling factors of engine systems in order to improve efficiencies of their operations. As to car engines, an increasing concern in environmental issues such as air pollution, global warming and petroleum depletion has helped drive researches into various ways. Laser diagnostics has been applied to measure species concentration in the actual industrial fields. However there are several challenges to proceed in applying laser diagnostics to practical application. Especially stability of the measurement system is one of the most difficult issues. The purpose of this research is the development of a prompt measurement technique which can be applicable to various engine conditions. The Tunable Diode Laser Absorption Spectroscopy （TDLAS） using the hollow fiber has been developed to satisfy above requirements. By using a hollow fiber, misalignment of an optical axis and vulnerability of measurement environment such as vibration can be greatly reduced with sensitive and fast response features. It was demonstrated that this method can be applicable to measure gas compositions in engine exhaust with a range of millisecond response time. A sensitive method using tunable UV diode laser absorption spectroscopy was also discussed to detect NOx in exhausts.

Contour Laser Guiding for the Mechanized ＂Vallerani＂ Micro-catchment Water Harvesting Systems

Mechanized construction of micro-catchments for water harvesting （WH） was successfully tested in the Badia （dry rangeland） areas in Syria and Jordan, using the ＂Vallerani＂ plow, model Delfino （50 MI/CM）, manufactured by Nardi, Italy. The plow was able to construct intermittent and continuous contour ridges, and could potentially be used to rehabilitate degraded rangelands. However, one major issue for large-scale implementation is the high cost and time required to manually identify contours for the plow to follow. Most existing auto-guiding systems, as usually used in road construction and agricultural land leveling, were expensive or impractical. The objective, therefore, was to add, adapt, and evaluate an auto-guiding system to enable a tractor to follow contours without demarcation through conventional surveying. A low-cost Contour Laser Guiding （CLG） system, with specifications that suit the contour ridging in undulating topographic conditions of dry rangelands, was chosen, adapted, mounted, and tested, under actual field conditions. The system consisted mainly of a portable laser transmitter and a tractor-mounted receiver, connected to a guidance display panel. The system was field-tested on 95 ha of land where the system capacity was determined under different terrains, slopes （1-8%）, and ridge spacings （4-12 m）. The easy adaptation and implementation of the CLG to the ＂Vallerani＂ unit tripled the system capacity, improved efficiency and precision, and substantially reduced the cost of constructing micro-catchments for WH. The system is recommended for large-scale rangeland rehabilitation projects in the dry areas, not only in West Asia, but worldwide.

Biosensing strategy based on photocurrent quenching of quantum dots via energy resonance absorption

A new concept of energy resonance absorption for photocurrent quenching was proposed using a system of quantum dots(QDs) and the matched dye. The QDs were used as the photocurrent producer, and the dye had an absorption band overlapped with that of the QDs, which led to the resonance absorption of the excitation energy and thus decreased the photocurrent of QDs. By using porphyrin and fluorscein isothiocyanate isomer I as the resonance absorption dyes, the proposed mechanism was proved by UV-Vis spectra, photoluminescence spectra and photocurrent-to-wavelength response, respectively. The interaction of the absorption-matched dye with biomolecule could be conveniently used to introduce it into the photocurrent quenching system, leading to a simple switch-off biosensing method for detection of the biomolecule. As example, a label-free method was proposed for photoelectrochemical detection of target DNA. This method showed a detection range from 6.0 to 600 nmol/L with a detection limit of 2.5 nmol/L. The result demonstrated that the photocurrent quenching via energy resonance absorption not only contributed to the theoretical study of photoelectrochemistry, but also provided a universal tool for photoelectrochemical biosensing.