3,990 research outputs found

    Modeling of the Reservoir Effect on Electromigration Lifetime

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    Electromigration behaviour in W-plug/metal stripe structures is different from conventional metal-strip structures because there is a blocking boundary formed by the immobile W-plug in the contact/via. Electromigration failures occur more readily close to the W-plug than in metal-strip structures because metal ions are forced away from the contacts/vias by electric current, blocking the contacts/vias area. Several works have reported electromigration lifetime of multiple level interconnects to be influenced by the presence of a reservoir around the contacts/vias. Reservoirs are metal parts that are not or are hardly conducting current that act as a source to provide atoms for the area around the blocking boundary where the atoms migrate away due to the electric current. Interconnect lifetime can be prolonged by using the reservoirs, called the ¿reservoir effect¿. 2D simulation of the effects of reservoirs has been performed. The stress build-up during electromigration in the contact area can be simulated for several configurations, separating the effects of overlap, total reservoir area, the reservoir layout directions (vertical and horizontal), number of contacts/vias and contact/via placement. It is very useful for IC design rules to estimate which parameters are important for IC reliability. In this study, we considered the critical stress that the metal line can sustain before void formation as failure criterion. The failure time is determined by the time to reach the critical stres

    Measurements of wavelength dependent scattering and backscattering coefficients by low-coherence spectroscopy

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    Quantitative measurements of scattering properties are invaluable for optical techniques in medicine. However, noninvasive, quantitative measurements of scattering properties over a large wavelength range remain challenging. We introduce low-coherence spectroscopy as a noninvasive method to locally and simultaneously measure scattering μs and backscattering μb coefficients from 480 to 700 nm with 8 nm spectral resolution. The method is tested on media with varying scattering properties (μs = 1 to 34 mm−1 and μb = 2.10−6 to 2.10−3 mm−1), containing different sized polystyrene spheres. The results are in excellent agreement with Mie theor

    Systemic defense priming by Pseudomonas putida KT2440 in maize depends on benzoxazinoid exudation from the roots

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    Exudation of benzoxazinoid metabolites from roots of young maize seedlings recruits the rhizobacterial strain Pseudomonas putida KT2440 from the soil to the rhizosphere. In this study, we have investigated whether these rhizobacteria are beneficial for maize by eliciting systemic defense priming. Root colonization of the maize hybrid cultivar Delprim by P. putida primed wound- and jasmonic acid (JA)-inducible emission of aromatic and terpenoid volatiles, but not the emission of the green leaf volatile (Z)-3-hexenyl acetate. Furthermore, root colonization by P. putida primed stress-inducible transcription of the JA-dependent gene SerPIN, whereas JA-dependent induction of the MPI gene was unaffected. Systemic priming of SerPIN by P. putida only occurred in benzoxazinoid-producing plants, and was absent in benzoxazinoid-deficient plants. The results from this study suggest that root colonization by P. putida primes a selection of JA-dependent defenses in Maize, which is reliant on benzoxazinoid exudation from the roots

    Pathogenesis, prevention, and management of bleeding and thrombosis in patients with liver diseases

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    Patients with liver diseases may develop alterations in all components of the hemostatic system. Thrombocytopenia, low levels of coagulation factors and inhibitors, low levels of fibrinolytic proteins, and increased levels of endothelial-derived proteins such as von Willebrand factor are all part of the coagulopathy of liver disease. Due to concomitant changes in pro- and antihemostatic drivers, the net effects of these complex hemostatic changes have long been unclear. According to current concepts, the hemostatic system of patients with liver disease is in an unstable balance, which explains the occurrence of both bleeding and thrombotic complications. This review will discuss etiology and management of bleeding and thrombosis in liver disease and will outline unsolved clinical questions. In addition, we will discuss the role of intrahepatic activation of coagulation for progression of liver disease, a novel paradigm with potential consequences for the general management of patients with liver disease.</p

    A state space model for exponential smoothing with group seasonality

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    We present an approach to improve forecast accuracy by simultaneously forecasting a group of products that exhibit similar seasonal demand patterns. Better seasonality estimates can be made by using information on all products in a group, and using these improved estimates when forecasting at the individual product level. This approach is called the group seasonal indices (GSI) approach, and is a generalization of the classical Holt-Winters procedure. This article describes an underlying state space model for this method and presents simulation results that show when it yields more accurate forecasts than Holt-Winters.Common seasonality; demand forecasting; exponential smoothing; Holt-Winters; state space model.