A surgical stapling device particularly suited for endoscopic procedures is described The device includes a handle assembly and an elongated body extending distally from the handle assembly The distal end of the elongated body is adapted to engage a disposable loading unit A control rod having a proximal end operatively connected to the handle assembly includes a distal end extending through the elongated body A control rod locking member is provided to prevent movement of the control rod until the disposable loading unit is fully secured to the elongated body of the stapling device

Surgical Stapling Apparatus

Most of the signal processing that we will study in this course involves local operations on a signal, namely transforming the signal by applying linear combinations of values in the neighborhood of each sample point. You are familiar with such operations from Calculus, namely, taking derivatives and you are also familiar with this from optics namely blurring a signal. We will be looking at sampled signals only. Let's start with a few basic examples. Local difference Suppose we have a 1D image and we take the local difference of intensities, DI(x) = 1 2 (I(x + 1) − I(x − 1)) which give a discrete approximation to a partial derivative. (We compute this for each x in the image.) What is the effect of such a transformation? One key idea is that such a derivative would be useful for marking positions where the intensity changes. Such a change is called an edge. It is important to detect edges in images because they often mark locations at which object properties change. These can include changes in illumination along a surface due to a shadow boundary, or a material (pigment) change, or a change in depth as when one object ends and another begins. The computational problem of finding intensity edges in images is called edge detection. We could look for positions at which DI(x) has a large negative or positive value. Large positive values indicate an edge that goes from low to high intensity, and large negative values indicate an edge that goes from high to low intensity. Example Suppose the image consists of a single (slightly sloped) edge:

http://ieeexplore.ieee.org/iel5/5/31307/01456462.pdf

Linear systems

Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation.

A Survey of Wide Bandgap Power Semiconductor Devices

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

/pdf/light-emitting-diodes-ubzde6g9qc.pdf

Light-emitting diodes

A surgical stapling instrument (1) comprises a body portion (2, 3), a handle (4) and a staple fastening assembly (8). The staple fastening assembly (8) includes a curved cartridge (10), which comprises at least one curved open row of staples, and a curved anvil (22), which is adapted to cooperate with the cartridge (10) for forming the ends of the staples exiting from the cartridge (10). The staple fastening assembly (8) is adapted to allow unobstructed access towards the concave inner faces of the cartridge (10) and the anvil (22). The cartridge (10) can be moved towards the anvil (22) from a spaced position for positioning tissue therebetween to a closed position for clamping the tissue. Preferably, a knife is contained within the cartridge (10) and is positioned such that there is at least one row of staples on at least one side of the knife.

Surgical stapling instrument

The series-capacitor buck converter doubles the duty ratio and equalizes the current between two phases. A series-resonator buck (SRB) converter is realized by adding a resonant tank in series with the series-capacitor Cs. All switches turn-on at zero voltage, and the low-side switches turn-off at zero current. This article focuses on modeling the steady-state operation of the SRB converter. The steady-state model calculates voltage gain, component peak voltages, and resonant inductor peak current. The understanding of the relationships between the voltage gain, regulating variable, and state variables help to optimize the power stage design. The expectations were validated by a 2-MHz converter with a peak efficiency of 98.5%, 48 V at the input and 7 V, 20 A at the output.

Steady-State Analysis of Series-Resonator Buck Converter

The effect of height on power density is examined for the practical ranges of power, frequency, loss, and volt-per-turn. Relevant mechanical and electrical equations are derived and applied to an optimization algorithm which searches for the design which maximizes the power density at a given height. It has been found that the curves of power density versus height exhibit a peak, on the order of 1000 W/in/sup 3/ in several cases, at a critical height between .25 to .3 in. Below this critical height, the power density decreases drastically. >

Effect of height on power density in high-frequency transformers

Packaging innovations are needed for medium-voltage wide bandgap power semiconductor modules to enable their adaptation in grid applications. A unique challenge for packaging medium-voltage power modules is managing the trade-off between insulation demand and heat dissipation. The focus of this work was on developing a packaging innovation that improves the module heat dissipation and offers more flexibility to its insulation design. Two strategies were explored for the packaging of an 8-kV SiC diode rectifier module:(1) double-side cooling and (2) sintered-silver bonding. Double-side cooling was realized by using short metal posts rather than long and thin wire bonds for device interconnection, forming a low-profile package with devices sandwiched between two insulated metal substrates. Sintered-silver bonding enabled the devices to function reliably at over 250 °C. Simulations of the packaged module showed a low interconnect inductance of 2.67 nH and a 50% less heat transfer coefficient required to cool the chips. Prototypes of the module were fabricated, and preliminary electrical testing results validated the package design.

Packaging of an 8-kV Silicon Carbide Diode Module with Double-Side Cooling and Sintered-Silver Joints

Transformer designs that achieve efficiencies greater than 99% operating at 2 MHz at power densities in excess of 400 W/in/sup 3/ for the power range of 50-100 W with output voltages of 1.5 V are discussed. To achieve these results, copper density must be increased beyond what is possible with more conventional Litz wire constructions. Instead, multilayer windings are made of copper foil using flex circuit technology. The elimination of external connections between the winding layers by incorporating the interconnections as an integral part of the winding design is described. This results in Z-folded winding structures that can be ultimately interleaved to achieve high copper density, low copper loss, and very low leakage inductance. >

http://ieeexplore.ieee.org/iel1/33/3225/00105124.pdf

Megahertz transformers for high density power conversion

Monolithic integration of DC-DC converters with on-chip inductors has emerged as a viable means to reduce size and increase transient performance for portable electronics applications High-power-density inductors have been recognized as a barrier for such integration In this paper, a CMOS-compatible process that is capable of fabricating on-chip inductors with low DC resistance and high power density is developed A unique silicon molding technique is used to obtain thick electroplating layers for cores and windings SU-8 is used as the isolation material between windings and cores A pot-core inductor with a low-frequency inductance of 134 nH and a dc resistance of 91 mOmega has been demonstrated

Khai D. T. Ngo

Papers

Steady-State Analysis of Series-Resonator Buck Converter

Effect of height on power density in high-frequency transformers

Packaging of an 8-kV Silicon Carbide Diode Module with Double-Side Cooling and Sintered-Silver Joints

Megahertz transformers for high density power conversion

SU-8 enhanced high power density MEMS inductors