A control system which consists of proportional and integral control to maintain the constant amount of dew was developed in this hygrometer. The dew points were measured within an accuracy of±1 °C in the ranging from -4 to 32°C. The response time for suddenly changing humidity was about 8 min.
In order to measure the total mass per unit area of dew droplets deposited on a metal plate in the dew-point hygrometer, the shape of a dew droplet deposited on a copper plate was measured accurately by using an interference microscope that employed a phase-shift technique. The microscope was constructed by adding a piezoelectric transducer to an usual interference microscope. A simple method that uses a conventional speaker horn and an optical fiber cable was introduced to depress speckle noise. The shape of a dew droplet deposited on the copper plate surface with 0.1 μm in average roughness was measured with an accuracy of ±3nm. The mass of a dew droplet could be calculated numerically from the volume of its shape and was of the order of 10-9 g. The total mass of dew droplets deposited per unit area and the deposition velocity were obtained under a gentle wind. The total mass was the order of 10-5 g/cm2 at the beginning of deposition and the deposition velocity was ranged from 2x10-6 to 6x10-5 g/cm2.min.
The ladder-Cu NMR spectrum of a structural disordered single crystal Sr 14 Cu 24 O 41 (Sr14-B) under a magnetic field H~11 T gradually splits into two spectra with Curie-like broadening as T decreases from TSP~150 K. Short-range (SR) staggered polarization (SP) on the ladder planes, originating from single- hole localization, occurs. The separation of the Sr14-B spectrum DH deviates from the Curie-like T dependence below 20 K. This assures that spontaneous moments appear below T N ~20 K in H~11 T
Pyrolytic graphite (HOPG) surfaces coated with gold particles of nanometer scale size have been studied to demonstrate the possibility of obtaining additional chemical surface data by obsery ing photon emission from the STM tunnel contact.
In order to study dropwise condensation on a metal plate, the method for controlling a tiny dew droplet deposited on a copper plate has been developed by using scattered laser light. The method employed the proportional control combined with shifting movement by an integrator to control the intensity of the scattered laser light constantly. Also, the control simulation of the method has been developed to confirm the usefulness of the method and the simulated three-dimensional shape of controlled dew droplet was obtained with the control action. A tiny thin dew droplet, of which the diameter was of handreds micrometers and the mass was about 10-7 g, was controlled in the atmosphere at room temperature for 60 minutes at the preset level of the intensity of scattered laser light and the three-dimensional shape of the controlled dew droplet was shown from the interference fringes.
Tiny droplets deposited on a copper plate were controlled and measured by a developed control technique and by using a simplified optical apparatus, white light and laser light. The technique employs the proportional control combined with shifting movement by an integrator. The droplets were controlled constant for thirty minutes at the preset level of the intensity of scattered light in a control circuit. The droplets were almost a hemisphere form in initial condensation at room temperature and were few tens micrometers in diameter. The controlled mass of a dew droplet was obtained from the volume of its shape and was of the order of 10-8 g.
In this paper, the technical training for fabricating the laser diode and photodiode modules and also assembling the electronic drives for the both modules is described from a view point of student technical training to study fundamental technology of optical fiber telecommunications. First, the students assembled the both modules using small parts and adjusted the optic axis of laser light from a source with an accuracy of a few micrometers so that the laser light efficiently enters the core of an optical fiber cable. The characteristics of the modules such as the spatial intensity distribution of emitted laser light, the relationship between the input laser power and the output current of a photodiode were measured to evaluate the fabricated modules. Second, two electronic analogue circuits of the drives used for the modules were assembled to study about typical optronics devices such as laser diode and photodiode, the functions of the circuits in the drives and how they are used in combination with the optical fiber telecommunications technology. Lastly, the fabricated modules and the assembled drives were tested by transmitting the test image using an optical fiber cable.
