A comparison of MOSFETs aging under d.c., a.c. and alternating stress conditions

The effects of static, alternating and dynamic stress conditions on the degradation rate of 0.8μm n- and p-channel LDD MOS transistors have systematically been investigated and compared. The shifts of the threshold voltage, transconductance, linear drain current and charge pumping current were used to monitor the transistor degradation. The results suggest that the aging induced by a dynamic stress cannot be directly explained with static stress models, essentially because it is highly dependent on a larger number of parameters (biases and durations of the top and bottom levels of the pulses, transient times). The correlation of static and dynamic stresses also clarifies the degradation mechanisms, in particular the role of hot holes in the generation of interface states.     

A survey on industrial communication networks

Industrial communication networks differ from other types of networks because these applications are responsible for the control and monitoring of a physical process. In this paper, we will summarise the requirements that users specify for these networks, present the state of art on field buses, factory and cell communication networks and indicate current research directions.     

Optimisation de ľefficacité de couplage entre un guide ďonde confiné et une fibre optique monomode par ľintermédiaire ďune lentille boule

Theoretical coupling efficiency between a channel waveguide and a single-mode optical fibre using a ball lens is optimized by varying the parameters of the optical system such as the relative position of the components, the refractive index and the size of the lens. A specific software has been used for the optimization. Numerical calculations have been done under the Gaussian approximation of the fields distributions. The losses due to waveguides misalignments with respect to their ideal position have been evaluated. All these theoretical results are compared with those obtained from buttcoupling.     

Theoretical analysis of a fractal surface radiation

We compare, in this paper, the far field radiated by two fractal distributions of current. The first one is obtained by a fractal cut following the Cantor arrangement, the second one keeps the length of each previous current element, but modifies the distance between the elements which is now taken as a constant. We establish the analytical formulations of the far field at any step n of the Cantor set. Then, we extract the array factor and we analyse and compare the following properties : convergence of the radiation pattern, wide of the main lobe, side lobes level and directivity.     

JPEG Pleno: Providing representation interoperability for holographic applications and devices

Guaranteeing interoperability between devices and applications is the core role of standards organizations. Since its first JPEG standard in 1992, the Joint Photographic Experts Group (JPEG) has published several image coding standards that have been successful in a plethora of imaging markets. Recently, these markets have become subject to potentially disruptive innovations owing to the rise of new imaging modalities such as light fields, point clouds, and holography. These so‐called plenoptic modalities hold the promise of facilitating a more efficient and complete representation of 3D scenes when compared to classic 2D modalities. However, due to the heterogeneity of plenoptic products that will hit the market, serious interoperability concerns have arisen. In this paper, we particularly focus on the holographic modality and outline how the JPEG committee has addressed these tremendous challenges. We discuss the main use cases and provide a preliminary list of requirements. In addition, based on the discussion of real‐valued and complex data representations, we elaborate on potential coding technologies that range from approaches utilizing classical 2D coding technologies to holographic content‐aware coding solutions. Finally, we address the problem of visual quality assessment of holographic data covering both visual quality metrics and subjective assessment methodologies.     

Analysis and Test of Resistive-Open Defects in SRAM Pre-Charge Circuits

In this paper, we present an exhaustive study on the influence of resistive-open defects in pre-charge circuits of SRAM memories. In SRAM memories, the pre-charge circuits operate the pre-charge and equalization at a certain voltage level, in general Vdd, of all the couples of bit lines of the memory array. This action is essential in order to ensure correct read operations. We have analyzed the impact of resistive-opens placed in different locations of these circuits. Each defect studied in this paper disturbs the pre-charge circuit in a different way and for different resistive ranges, but the produced effect on the normal memory action is always the perturbation of the read operations. This faulty behavior can be modeled by Un-Restored Write Faults (URWFs) and Un-Restored Read Faults (URRFs), because there is an incorrect pre-charge/equalization of the bit lines after a write or read operation that disturbs the following read operation. In the last part of the paper, we demonstrate that the test of URWFs is more effective in terms of resistive defect detection than that of URRFs and we list the necessary test conditions to detect them.

金属沾污对超薄栅氧(2. 5nm)特性的影响

采用可控的金属沾污程序 ,最大金属表面浓度控制在 10 1 2 cm- 2数量级 ,来模拟清洗工艺最大可能金属沾污表面浓度 .利用斜坡电流应力和栅注入方式测量本征电荷击穿来评估超薄栅氧特性和金属沾污效应 .研究了金属锆和钽沾污对超薄栅氧完整性的影响 .实验结果表明金属锆沾污对超薄栅氧完整性具有最严重危害 ;金属钽沾污的栅氧发生早期击穿现象 ,而金属铝沾污对超薄栅氧完整性没有明显影响 .     

Occurrence and significance of anomalous chloride waters at the Orakei Korako geothermal field, Taupo Volcanic Zone, New Zealand

Water with Cl concentrations from 15 to almost 10,000 mg/kg, and molecular SO₄/Cl ratios ranging from 0.003 to 1.87, drips periodically from the roof of Ruatapu cave and a side chamber, Rahu Rahu, located in the Orakei Korako geothermal field, Taupo Volcanic Zone, New Zealand. Pools in the bottom of both Ruatapu and Rahu Rahu contain sulfate–chloride waters with pH values ranging from 2.5 to 3.0; their Cl contents have varied temporally from 120 to 240 mg/kg and their molecular SO₄/Cl ratios from 0.86 to 1.30. The Cl in the water dripping from the cave roof cannot come directly from the alkali chloride–bicarbonate water that circulates in the reservoir at Orakei Korako since the modern and historic piezometric surfaces are several meters below the cave roof. Nor does all the Cl in the cave pool waters derive from the reservoir fluid as the volume input required is incompatible with their Na and K contents. A more likely source for the Cl is one whereby rain water, percolating through the fractured rhyolitic country rock, dissolves Cl present either in glass shards or halite deposited in prehistoric times when trapped alkali chloride water boiled to dryness. Given that Cl in the cave pool waters is therefore supplied from a source above rather than, as previously assumed, below, the axiom that Cl present in acid sulfate–chloride ± bicarbonate waters is necessarily a signature of a deep water or magmatic input needs qualification.     

Chemical composition of melia volkensii gurke: An unrealised browse potential for semi-arid agroforestry systems

Results of chemical analyses of some nutritional characteristics of Melia volkensii browse, important for large wild and domestic herbivores in East Africa, are presented. Seeds, fruit pulp, leaves and twigs had high levels of crude protein, crude fat, minerals and fibre. Newly coppiced shoots (leaves and twigs), old shoots, fruit pulp and seed contained 230, 190, 130 and 320 g kg^-1 dry weight crude protein, respectively. The essential amino acid profile compared well with the FAO scoring pattern. Tyrosine was the first limiting amino acid in the coppice leaves and twigs, lysine in the cotyledons, and threonine and lysine in the endosperm. The concentrations of crude fat in the seed, fruit pulp, coppice shoots and old shoots were 480, 100, 80 and 50 g kg^-1, respectively. The fatty acids in the cotyledon and endosperm were mainly palmitic (110 and 109 g kg^-1, respectively), oleic (327 and 252 g kg^-1, respectively) and linoleic (487 and 573 g kg^-1, respectively). The levels of P, Na, K, Ca, Mg and the Ca/P ratio per kg dry weight were on average higher than the optimum recommended for ruminants. These results demonstrate that M volkensii browse, especially coppice leaves and twigs, have a high index for nutrient content, and the planting of this species should be promoted in the semi-arid areas to supplement senescent grasses and cereal crop residues.     

Volatile constituents of palm wine and palm sap

Palm wine and pasteurised palm sap volatiles were collected, concentrated on a Tenax GC and analysed by gas chromatography and gas chromatography-mass spectrometry. Eighty-two components were identified: 47 esters, 9 alcohols, 5 acids, 6 carbonyls, 2 acetals, 4 terpenes and 9 hydrocarbons. These had all been found previously in conventional wines. Odour evaluation of the separated palm wine components as they eluted suggested that no one compound is responsible for the characteristic palm wine odour. The acetates of higher alcohols and the ethyl esters of straight-chain aliphatic C₆-C₁₀ acids seemed to be important and may play a big role in imparting the fruity nuances of characteristic palm wine odour. Their association with alcohols seemed also to be necessary for the expression of typical palm wine odour. The qualitative difference between palm sap aroma and palm wine aroma appeared to be due mainly to the presence of these esters and alcohols in palm wine and their apparent absence from palm sap, as well as to the presence of some low-boiling esters and alcohols in palm sap and their apparent absence from palm wine.