智能弗兰克-赫兹实验测量仪的研制

采用AT90S 8535单片机研制了一种智能弗兰克－赫兹实验测量仪，能测量10^-9-10^-12A微电流，提供0－50V线性程控稳压电源，模糊控温，图形液晶显示中英和曲线，曲线数据打印，具有测量快、精度高、体积小、成本低、使用方便等优点。本介绍了该测量仪的硬件组成、典型电路工作原理、软件设计，分析了实验结果。     

An instrument for quantifying honey bee defensiveness

A new instrument for evaluating the characteristics of honey bee stinging attacks has been developed. The new instrument includes a new, hollow target device that utilizes the sound created when it is made to ring at its natural frequency. In operation, bees strike the shell of the target while attempting to sting it, causing the target to ring at its natural frequency. This sound is detected by a microphone placed inside the target and an electric signal is sent to the instrument. There each strike by a bee is counted during a defined interval. The total is stored in memory and the next interval is immediately counted. When the stored data are downloaded into a computer the temporal patterns of bee attack can be studied. Initial studies suggest that when a colony of bees is stimulated to attack several times, each subsequent attack becomes more intense.     

An instrument for measuring low optical rotation angle

This paper develops a linear heterodyne interferometer based on phase-locked extraction for measuring low optical rotation angle. The validity of the proposed design is demonstrated by measuring a half-wave plate. The average relative error in the measured rotation angle of the half-wave plate is determined as just 0.74%. When applied to the measurement of glucose solutions with concentrations ranging from 0 to 1.2 g/dl, the average relative error in the measured rotation angle of glucose solutions is determined to be 1.46%. The correlation coefficient between the measured rotation angle and the glucose concentration is determined to be 0.999991, while the standard deviation is just 0.00051°. The current system is capable of measuring glucose concentration as low as 0.01 g/dl with an error of 6.67% in the rotation angle measurement. Overall, the experimental results demonstrate the ability of the proposed system to obtain highly accurate measurement of the optical rotation angle.     

An entropy inequality for quantum measurements

It is proved that for an ideal quantum measurement the average entropy of the reduced states after the measurement is not greater than the entropy of the original state.     

An ultrasonic instrument for rapid B-scanning of the heart

A rapid ultrasonic B-scan instrument has been constructed for scanning the heart. An important factor in its design has been the need to make the maximum use of the points on the chect from which ultrasound can be transmitted into the heart avoiding bone and lung. A high degree of flexibility in the manipulation of the direction of the ultrasound beam allows the cardiac structures to be thoroughly scanned. Finally, since the system operates by rapidly moving a standard transducer, it is possible to use it to perform the more established ultrasonic techniques for heart examination such as time-motion scanning.     

An instrument for measuring branching ratios in photoionizing processes

An instrument using photo-electron spectrometry has been developed to measure branching ratios and relative partial cross-sections for photoionizing processes in gases, with particular emphasis given to measuring variation of these parameters as a continuous function of wavelength. The instrument is described together with a consideration of sources of errors and a method of calibration.     

An acoustic chamber for sound intensity measurements

The construction and performance of an acoustic chamber suitable for sound intensity measurements is described. The walls and the ceiling of the room are treated with glass wool sheets, air gap and pleated carpet in that order for sound absorption. The final testing of the room shows that good sound absorption is obtained down to low frequencies. The sound absorption coefficient for the room varies between 0.83 and 0.91 for different frequencies.