Bonding silicon wafer to silicon nitride with spin-on glass as adhesive

Using spin-on glass (SOG) as an adhesive, an Si wafer with thermal oxide was successfully bonded to one with an RF-sputtered Si3N4 film. This ensures that SOG films are effective in bonding Si wafers to less reactive surfaces than Si or SiO2 such as silicon nitride. It was also found that the previously reported bonding procedure can be simplified by suppressing the spin-induced radial striations of the SOG films.     

Temperature-stable low-noise ferrite memory cores

Temperature-stable low-noise memory cores made from the substituted lithium and nickel ferrites were studied. Ferrite compositions which are suitable for miniature cores have been developed by studying magnetic properties of the ferrite in the system Li-M-M' and Ni-M-M' ferrite (M:Mn, Fe, Co, Ni, Cu, and Zn). Technological approaches for fabricating small memory cores were made by studying the effect of ferrite-powder parameters and sintering conditions on magnetic properties of the substituted ferrites. Typical pulse characteristics taken with coincident current mode for cores of 0.48, 0.32, and 0.27 mm φ OD are presented. It was found that the Ni-Mn-F(II) ferrites are suitable for a low-drive high signal-to-noise ratio (dV1/dVz) temperature-stable memory core.     

Trends in highly scalable crossbar-based packet switch architecture

A combined input and crosspoint queued (CICQ) switch is receiving significant attention to be the next generation high speed packet switch for its scalability; however, a multi-cabinet implementation of a combined input and crosspoint queued (CICQ) switch unavoidably introduces a large round-trip time (RTT) latency between the line cards and switch fabric, resulting a large crosspoint (CP) buffer requirement. In this paper, virtual crosspoint queues (VCQs) that significantly reduces the CP buffer requirement of the CICQ switch is investigated. The VCQs unit resides inside the switch fabric, is dynamically shared among virtual output queues (VOQ) from the same source port, and is operated at the line rate, making the implementation practical. A threshold-based exhaustive round-robin (T-ERR) arbitration is employed to reduce buffer hogging at VCQ. The T-ERR at VCQ and CP arbiters serves packets residing in a longer queue more frequently than packet residing in a shorter queue. Consequently, the T-ERR, drastically increases the throughput of the CICQ switch with small CP buffers. A multi-cabinet implementation of CICQ switch do not support multicasting traffic well since a combination of small CP buffer in the switch fabric and a large RTT latency between the line cards and switch fabric results in non-work conservation of the intra-switch link. Deployment of multicast FIFO buffer between the input buffer and CP buffer shows a promise. With its ability to achieve high throughput independent of RTT and switch port size, the integration of the VCQ architecture and T-ERR scheduler to the CICQ switch is ideal for supporting ever-increasing Internet traffic that requires higher data rate, larger switch size, and efficient multicasting.     

Multi-contact vertical ladder climbing with an HRP-2 humanoid

We describe the research and the integration methods we developed to make the HRP-2 humanoid robot climb vertical industrial-norm ladders. We use our multi-contact planner and multi-objective closed-loop control formulated as a QP (quadratic program). First, a set of contacts to climb the ladder is planned off-line (automatically or by the user). These contacts are provided as an input for a finite state machine. The latter builds supplementary tasks that account for geometric uncertainties and specific grasps procedures to be added to the QP controller. The latter provides instant desired states in terms of joint accelerations and contact forces to be tracked by the embedded low-level motor controllers. Our trials revealed that hardware changes are necessary, and parts of software must be made more robust. Yet, we confirmed that HRP-2 has the kinematic and power capabilities to climb real industrial ladders, such as those found in nuclear power plants and large scale manufacturing factories (e.g. aircraft, shipyard) and construction sites.     

Achieving evenhandedness in certified email system for contract signing

Certified email is a system which enables a sender to prove a receiver’s receipt of email. Such a system can be used for applications related to electronic commerce on the Internet. This paper considers a situation where a sender or a receiver wants to change his/her mind due to the change of mail content value (e.g., stock, auction, gambling) during the transaction. We point out that no traditional certified email systems have been designed for such a case, thus one of the participants can be at a disadvantage. To avoid this problem, we propose an evenhanded certified email system in which each participant can change his/her choice, either cancel or finish the transaction, at any time during the transaction.

Patient-specific computer modeling of blood flow in cerebral arteries with aneurysm and stent

We present the special arterial fluid mechanics techniques we have developed for patient-specific computer modeling of blood flow in cerebral arteries with aneurysm and stent. These techniques are used in conjunction with the core computational technique, which is the space?Ctime version of the variational multiscale (VMS) method and is called ??DST/SST-VMST.?? The special techniques include using NURBS for the spatial representation of the surface over which the stent mesh is built, mesh generation techniques for both the finite- and zero-thickness representations of the stent, techniques for generating refined layers of mesh near the arterial and stent surfaces, and models for representing double stent. We compute the unsteady flow patterns in the aneurysm and investigate how those patterns are influenced by the presence of single and double stents. We also compare the flow patterns obtained with the finite- and zero-thickness representations of the stent.     

Lattice parameter determination of a strained area of an InAs layer on a GaAs substrate using CBED

All the six lattice parameters (a, b, c, alpha, beta and gamma) of a strained area of an InAs layer grown on a GaAs substrate were determined without any assumption of the crystal lattice symmetry from the higher-order Laue zone (HOLZ) lines appearing in one convergent-beam electron diffraction (CBED) pattern. The analysis was performed with three steps. Firstly, the parameters alpha and beta were determined from the deviations of the HOLZ lines from the mirror symmetry perpendicular to the [001] direction. Secondly, the parameter c was determined from the distance between the intersections of the HOLZ lines, which have the same h and k indices but different l indices. Finally, the parameters a, b and gamma were determined simultaneously from several distances between the intersections of the HOLZ lines. The lattice parameters determined for the strained area were a = 0.611(2) nm, b = 0.615(1) nm, c = 0.6119(7) nm, alpha = 89.5(1) degrees, beta = 89.0(2) degrees and gamma = 89.1(2) degrees. This result implies that the cubic lattice of InAs is elongated approximately in the [111] direction and the exact lattice symmetry is triclinic. The same analysis procedure was applied to another two specimen areas. It was found that the areas have orthorhombic distortions with lattice parameters a = 0.607(2) nm, b = 0.604(1) nm and c = 0.6085(7) nm for one area, and with a = 0.607(2) nm, b = 0.605(1) nm and c = 0.6065(7) nm for the other area. It is should be emphasized that the present analysis of lattice distortions is immediately applicable to the other semiconductors, such as Si, SiGe or GaAs layers, without assuming any crystal system.