Muddy Waters and the Iron Depth Charge

The problem of how to defend the myriad of shipping assets that must transit in and out of shallow water in time of war has plagued naval planners since World War I. Whether it be the delivery of materiel to ports or the opposed amphibious assault in a hostile environment, the successful completion of nearly every naval evolution terminates in shallow or restricted waters of some type. It is in these waters that the advantages of conventional submarines outweigh the advantages of nuclear-powered ones and any disadvantages of the former are reduced

Process Development for the Formation of Post-Bonding Biorecognition Layers in Microfluidic Biosensors

Formation of the biorecognition layers within microfluidic sensor channels must be done after the completion of the channel structure since these layers cannot withstand the wafer bonding temperature. We propose a new post-bonding immobilization process to prepare the enzyme layers within microfluidic channels of electrochemical biosensors. An array of Pt vertical electrodes is electroplated using a SU-8 mold. The cured SU-8 is then removed by plasma etching to expose the Pt electrode and to define the fluidic channel cavity simultaneously. An array of enzyme posts is formed on the Pt surface by either electropolymerizing or photopolymerizing enzyme precursor solutions injected into the channel. Very little report is available about the reactive ion etching (RIE) of SU-8 that is the most critical step in this process. A systematic investigation on the RIE of SU-8 is conducted to obtain the maximum etch rate (1.2 ¿m/min.) based on different combinations of parameters of CF4 and O2 gas flow, RF power and time

Development and Application of a High-Resolution Thin-Film Probe

This paper documents the development, characterization, and application of a high-resolution thin-film magnetic-field probe. Probe diameter ranged from 5-μm to 100-μm. The 100-μm probe exhibits a 250-7μm improvement in spatial resolution compared to a conventional loop probe, measured at a height of 250 μm over differential traces with a 118-μm spacing. Electric field rejection was improved using shielding and using a 180-degree hybrid junction to separate common-mode (electric field) and differential-mode (primarily magnetic field) coupling. A network analyzer with narrow band filtering was used to detect the relatively weak signal from the probe and to allow detection of phase information. An application of the probe is demonstrated where the probe is used to identify the magnitude and phase of magnetic fields produced by currents in very closely-spaced IC package pins

Protecting the Carrier Against Torpedo Attack

The prospect of torpedo attack against our high-value units periodically rears its ugly head and then submerges again as technology and tactics are developed to counter this threat, In our century\u27s wars each major threat to the high-value unit was analyzed and dealt with after a few (or in some cases, a lot) of important ships were sunk in almost every case the most efficient and cost-effective mechanism used to attack these ships was a torpedo

Fabrication of Two-Layer Thin-Film Magnetic-Field Microprobes on Freestanding SU-8 Photoepoxy

Development and testing of a two-sided magnetic-field microprobe using freestanding SU-8 photoepoxy as the insulating material are presented. Sputter-deposited thin-film silver conductors, patterned using a modified lift-off technique, were used as the loop and shielding traces on opposite sides of the SU-8 dielectric. Removal of the patterned probes from a silicon-carrier substrate was done by wafer dicing individual probes and undercutting a sacrificial silicon dioxide layer on the wafer surface. Assembly of the probe was accomplished using gold wire and electrically conductive epoxy on a printed circuit platform. Test measurement results indicate that the magnetic field from each of the two 500-μm-wide circuit traces separated by a 100-μm spacing can be readily resolved