For large-scale measurement of microbubble parameters on the ocean surface beneath breaking waves, a buoy-type bubble sensor (BBS) is proposed. This sensor integrates a panoramic bubble imaging sub-sensor with a circular array fiber-optic sub-sensor. The sensitive unit of the latter sub-sensor is designed via theoretical modeling and experimental validation. Theoretical calculations indicate that the optimal cone angle for a quartz fiber-optic-based sensitive unit ranges from 45.2° to 92°. A prototype array element with a cone angle of 90° was fabricated and used as the core component for feasibility experiments in static and dynamic two-phase (gas and liquid) identification. During static identification, the reflected optical power differs by an order of magnitude between the two phases. For dynamic sensing of multiple microbubble positions, the reflected optical power varies from 13.4 nW to 29.3 nW, which is within the operating range of the array element’s photodetector. In theory, assembling conical quartz fiber-based sensitive units into fiber-optic probes and configuring them as arrays could overcome the resolution limitations of the panoramic bubble imaging sub-sensor. Further discussion of this approach will be presented in a subsequent paper.

An automatic document feeder (ADF) is an important part of a copier, which is capable of feeding a document for double-sided scanning, includes mechanical structure and control system. Control system is the core unit, which is responsible for original feeding, original separation, original registration, original conveyance, etc. Control system will directly affect the accuracy of machine efficiency. In order to design control system, mathematical model should be welldesigned first. The original-feeding system of an ADF is controlled and validated in this paper. The ADF studied here is a prototype developed by Konica, a company that develops professional printing systems. We construct a model of original-feeding system for the ADF in Simulink, and software which is using for modeling dynamic system, simulating and analyzing, and express the PID gains. Next, we contrast original feed motor's speed on real condition to simulation results for checking whether the PID gains are reasonable. The comparison shows the upward trend in motor speed is similar, and the actual rise time is shorter. The reason for that is: the test data on real condition focus on the moment when the original feeds in, all the loads involved in simulation are not added to motion control system. In this sense, in addition to finding better PID gains in the ADF motion control system, our analysis also led to a better understanding of system.