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

Voltage of a bus capacitor in a cascaded buck-boost power amplifier is controlled to shape current in an inductive load. Switch-mode converter and inverter output higher power with higher efficiency than linear amplifiers. However, controlling current in the inductive load with low damping is not straightforward due to its inherent instability. Voltage-mode control of a front-end buck converter adjusts the envelope of the load current through a downstream resonant boost inverter and stabilizes the system. The resonant boost inverter is modeled into a low-frequency equivalent circuit, and a control loop is designed to avoid interaction between the buck converter and resonant boost inverter. Experimental results proved that the buck converter with the voltage loop of which bandwidth and phase margin are 150 kHz and 67° shaped the envelope of load current into 10-kHz (23.5-kHz) sine wave when the average output power was 320 W (90 W). Instantaneous maximum power of the prototype circuit was 2.3 kW and estimated efficiency was 96%.

Bus Voltage Control of Cascaded Buck–Boost Power Amplifier Driving Inductive Load With 2.3-kW Peak Power

All input and output inductors of a resonant cross-commutated buck (rccBuck) converter are coupled to shrink the core size while maintaining efficiency. The steady-state current ripples of the omnicoupled Inductors (OCI) are modeled by separating common-mode and differential-mode voltages. The coupling coefficients are derived to minimize inductance and energy. In this article, the twisted E-E cores with one-turn printed circuit board (PCB) windings are proposed to realize the recommended coupling coefficients. The magnetic flux paths and reluctances are analyzed. A prototype was fabricated to demonstrate the OCI in a 2-MHz rccBuck converter with 12-V input and 3.3-V output. Magnetic volume was 57% smaller and efficiency was 0.5% higher (over the entire load range) than those of the reference rccBuck converter with discrete inductors.

Omnicoupled Inductors (OCI) Applied in a Resonant Cross-Commutated Buck Converter

The layout of power modules is one of the key points in power module design, especially for high power densities, where couplings are increased. In this paper, along with the design example, an automatic design processes by using genetic algorithm are presented. Some practical considerations and implementations are introduced in the optimization of the layout design of the module.

Automatic layout design for power module

The problem of finding the inductance of a conductor that is woven through holes in a flat plate of magnetic material is addressed. The unusual geometry is attractive for the construction of low-profile inductors and transformers for switched-mode power converters. The presence of magnetic material in the winding window makes it difficult to calculate inductance. Conventional methods may underestimate the inductance of the new devices by as much as 50%. Finite-element simulation provides guidance for physical modeling of these geometries. An analytical approach is presented with expressions which are compared with finite-element solutions and verified by experiment. The analysis suggests design guidelines for practical applications of perforated-plate magnetic devices. >

Inductance modeling for a mode-2 perforated-plate matrix inductor/transformer

Triple points on direct-bond copper substrates for packaging medium-voltage power modules are locations of high electric-field stress responsible for partial discharge in the encapsulation material. In this work, a nonlinear resistive polymer-nanoparticle composite was tested for coating the triple points to reduce the electric-field intensity. This approach of field grading avoided using thick layers of insulation, thus improving the thermal performance of the module. The field-grading effect was first analyzed by COMSOL field simulations. The maximum electric-field intensity at the triple points of a coated alumina direct-bond-copper substrate was reduced by up to 43%. This field reduction was verified from a measured increase of 86% in the partial discharge inception voltages of coated over uncoated substrates encapsulated in a silicone gel. Coated substrates with 1-mm thick alumina and 3-mm trench gap were found to have no partial discharge higher than 10 pC under 19 kV for 5 minutes, leaving a significant insulation margin for packaging 15-kV silicon carbide power devices. Given its processing simplicity and effective field-stress reduction, the nonlinear resistive composite offers a low-cost solution for packaging medium-voltage power devices without compromising the package thermal performance.

Field-Grading Effect of a Nonlinear Resistive Polymer-Nanoparticle Composite Triple-Point Coating on Direct-Bond Copper Substrates for Packaging Medium-Voltage Power Devices

Khai D. T. Ngo

Papers

Bus Voltage Control of Cascaded Buck–Boost Power Amplifier Driving Inductive Load With 2.3-kW Peak Power

Omnicoupled Inductors (OCI) Applied in a Resonant Cross-Commutated Buck Converter

Automatic layout design for power module

Inductance modeling for a mode-2 perforated-plate matrix inductor/transformer

Field-Grading Effect of a Nonlinear Resistive Polymer-Nanoparticle Composite Triple-Point Coating on Direct-Bond Copper Substrates for Packaging Medium-Voltage Power Devices