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

Planar coils are popularly used in inductive power transfer applications. The coils’ efficiency is improved with litz wire by eliminating the winding's skin-effect loss, but the proximity-effect loss still needs to be considered. To calculate the proximity-effect resistance, the magnetic fields across the windings are required. During the coils’ optimization process, numerical methods of field calculation are too time-consuming due to the parametric sweep of physical parameters. The analytical calculation of the magnetic field is preferred in this scenario, but it becomes complex with the existence of the ferrite plate, which is used to increase the coils’ coupling. In this paper, the method of image is applied to simplify the analytical calculation, in which the magnetic fields across the windings are derived from Ampere's law and Biot–Savart law. The proximity-effect resistance is then calculated with these fields. The study also proves that the size of the ferrite plate has negligible influence on the proximity-effect resistance as long as it is larger than the size of the winding. A planar coil was fabricated and measured to verify the analytical calculation of the proximity-effect resistance, using litz wire composed of 100 strands with 0.1 mm diameter. A square plate of 3C96 ferrite with the dimensions of 100 mm × 100 mm × 5 mm was placed below the winding. The difference between calculation and measurement is less than 15%.

Analytical Calculation of Proximity-Effect Resistance for Planar Coil With Litz Wire and Ferrite Plate in Inductive Power Transfer

Vorperian's pulsewidth modulation (PWM) switch model consists of a PWM transformer and a nonlinear resistor. The recognition that any of the three transformer terminals can serve as the common terminal leads to two alternate PWM transformer models and the corresponding two alternate PWM switch models. For a given PWM dc-dc converter, one of the three PWM switch models is more "natural" for graphic-oriented analysis/design, e.g., it allows the idealized converter to be analyzed by inspection. Furthermore, all three PWM transformers may be used to graphically manipulate the converter circuit to a form that can be analyzed by inspection. The alternate forms of the PWM transformers and the PWM switch models are effective as graphic-oriented teaching and learning tools for PWM converters. This is demonstrated using examples based on the boost converter and the Cuk converter.

Alternate forms of the PWM switch models

An analytical model has been developed for predicting the forced-air cooling system performance, including a detailed optimization process to minimize the total weight. With a design example in a high-density high-temperature SiC converter, the presented design method was verified through numerical simulations and experiments.

Forced-Air Cooling System Design Under Weight Constraint for High-Temperature SiC Converter

This paper shows that a switched-capacitor DC-DC converter can be designed to process up to several tens of watts of output power at an efficiency exceeding 80%. Converter operation is analyzed by "modified state-space-averaging", which is generally suitable for analysis of converters with nonlinear ripple. A design procedure is presented along with experimental verification. >

Operation and design of a switched-capacitor DC-DC converter with improved power rating

The series-capacitor buck converter doubles the duty ratio, and equalizes the current between two phases A series-resonator buck 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 The resonant tank generates additional loss and increases the voltage stress of the low-side switches A 2-MHz prototype with a peak efficiency of 985%, 48 V at the input and 7 V, 20 A at the output was built to demonstrate the viability of the topology

Khai D. T. Ngo

Papers

Analytical Calculation of Proximity-Effect Resistance for Planar Coil With Litz Wire and Ferrite Plate in Inductive Power Transfer

Alternate forms of the PWM switch models

Forced-Air Cooling System Design Under Weight Constraint for High-Temperature SiC Converter

Operation and design of a switched-capacitor DC-DC converter with improved power rating

Series-Resonator Buck Converter—Viability Demonstration