Abstract: A recording apparatus set on a car for recording vehicle condition includes at least one camera arranged to photograph the car, and a controller arranged to control the at least one camera to photograph the car exterior and the car interior when an indication signal received by the controller indicates that the car is being picked up, and arranged to control the at least one camera to photograph the car exterior and the car interior when the indication signal received by the controller indicates that the car is being returned.

Abstract: A method of establishing a database of gas molecules is disclosed. In this method, a metal-organic framework absorbs gas molecules of a guest material. Thereafter, after a predetermined time, the thermogravimetric analyzer (TGA) is utilized to make sure that the gas molecules have been adsorbed by the metal-organic framework. Finally, the metal organic framework with the gas molecules adsorbed thereon is analyzed by fluorescence spectrophotometer, and the light-emitting wavelength and waveform are recorded to establish a database of gas molecules.

Abstract: A system of measuring pH of a solution having a calibration device to counteract time-drift effect. The calibration device of the system adjusts a compensation voltage to zero a measuring voltage of a first sensor and only respond to time-drift voltage of the first sensor. The calibration device has a differential operation amplifier receiving measuring voltages from the first sensor and a second sensor of the system to eliminate the time-drift voltages of the first and second sensors, thereby achieving calibration of the time-drift effects.

Abstract: A system of measuring pH of a solution having a calibration device to counteract time-drift effect. The calibration device of the system adjusts a compensation voltage to zero a measuring voltage of a first sensor and only respond to time-drift voltage of the first sensor. The calibration device has a differential operation amplifier receiving measuring voltages from the first sensor and a second sensor of the system to eliminate the time-drift voltages of the first and second sensors, thereby achieving calibration of the time-drift effects.

Abstract: A light reflector is mounted to a personal item, such as shoe, clothes, and hats. The light reflector includes a light reflective base plate having a surface on which at least one light reflecting cone is formed for reflecting light incident onto the reflector. The light reflector has a light non-transmitting layer formed on a surface thereof except the portion where light transmits into the light reflector. The light non-transmitting layer prevents the reflected light from being randomly dispersed. The cones may be formed of a plurality of flat faces having different angular orientations whereby light is reflected in such a way to provide shining and glaring effect.