A Preconditioned Waveform Relaxation Solver for Signal Integrity Analysis of High-Speed Channels

This work presents a fast transient solver for Signal Integrity analysis of high-speed channels. We consider general chip-to-chip coupled interconnect structures, including arbitrary discontinuities at chip, package and board level. An external characterization of the interconnect in terms of tabulated scattering frequency samples is first converted to a closed-form macromodel, whose transient effects on input signals can be computed very efficiently through recursive convolutions. When combined with suitable models for drivers and receivers, a large-scale but very sparse system of equations is obtained. The latter is solved by an iterative scheme based on the Generalized Minimal RESidual (GMRES) method, further enhanced by a preconditioner based on Waveform-Relaxation. Contrary to previous formulations, the proposed scheme is guaranteed to converge in few iterations. Numerical examples show that the proposed solver outperforms standard SPICE in terms of runtime, with no loss of accuracy

The distribution and concentration of particulate biogenic silica in surface waters of Prydz Bay, Antarctica, during the austral summer of 2011

The concentrations and distributions of particulate biogenic silica (PBSi) in the upper surface waters of Prydz Bay, Antarctica, were investigated during the 27th Chinese National Antarctic Research Expedition cruises of January 2011. We aimed to characterize the correlations between PBSi and plankton, nutrients and particulate organic carbon. The results showed that the concentrations of biogenic silica ranged from 0.76—19.72 μmol∙dm-3 and the average concentration of biogenic silica was 6.06 μmol∙dm-3. The distribution of surface PBSi had significant regional characteristics: The concentrations were higher south of 67°S than to the north. The distribution of PBSi, chlorophyll a and particulate organic carbon showed similar patterns, and PBSi distribution had a negative correlation with that of silicate. In the vertical direction, the mole ratio of PBSi and POC (Sibio/Corg) decreased with increasing depth. This trend indicated a higher rate of PBSi dissolution, or a lower rate of organic matter remineralization rate, in the upper 200 m

The content and distribution of Ge in the sediments of Prydz Bay, Antarctica

The content and distribution of Ge is investigated in sediments from the Southern Ocean (Prydz Bay, Antarctica). The content of Getotal in the sediments ranges from 1.14×10-6 to 2.35×10-6 (average of 1.71×10-6) and the highest value occurs at station P3-9 where water depth is > 1 000 m. The lowest value occurs at station P4-13 which is near the edge of the Amery ice shelf. The surface sediments have 16%–68% Gebio within Getotal. The distribution trends of Gebio and Getotal are generally similar, and the values outside Prydz Bay are higher than within the bay, bounded at 67°S. The vertical distribution of Ge in sediment cores presents higher values at the surface than in underlying sediments. Values of Gebio appear to positively correlate with biogenic silica (BSiO2) in surface sediments from non-polynyas sea. The vertical distribution of Gebio and BSiO2 is similar in sediments of station P3-16

Design and preparation of a novel colon-targeted tablet of hydrocortisone

The objective of this research was to design a new colon-targeted drug delivery system based on chitosan. The properties of the films were studied to obtain useful information about the possible applications of composite films. The composite films were used in a bilayer system to investigate their feasibility as coating materials. Tensile strength, swelling degree, solubility, biodegradation degree, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM) investigations showed that the composite film was formed when chitosan and gelatin were reacted jointly. The results showed that a 6:4 blend ratio was the optimal chitosan/gelatin blend ratio. In vitro drug release results indicated that the Eudragit- and chitosan/gelatin-bilayer coating system prevented drug release in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). However, the drug release from a bilayer-coated tablet in SCF increased over time, and the drug was almost completely released after 24h. Overall, colon-targeted drug delivery was achieved by using a chitosan/gelatin complex film and a multilayer coating system

Magnetic Separation of Impurities from Hydrometallurgy Solutions and Waste Water Using Magnetic Iron Ore Seeding

The removal of iron ion from leaching solution is critical for the recovery of value metals, with the method of choice commonly being crystallization (precipitation). This paper summarized the new improvements in iron removal by precipitation methods in recent years and proposed a novel process, magnetic seeding and separation. The new process can promote iron precipitate aggregation and growth on the surface of the magnetic iron ore seeds. A core-shell structure was formed of iron precipitate and magnetic iron ore seeds, which can be magnetized and coalesced in magnetic field, accelerating the solid-liquid separation. The efficient magnetic flocculation and separation offset the poor settleability and filterability of the residues, contributing to the development of the hydrometallurgy process. Moreover, magnetic seeding and separation was also used for the removal of organic and inorganic contaminants from wastewater, significantly improving the purification efficiency. Therefore, iron ore not only played an important role in mining and steel manufacture, but also can be used to solve some problems in crossing fields

A Facile and Generic Strategy to Synthesize Large-Scale Carbon Nanotubes

An easy method to prepare carbon nanotubes (CNTs) has been demonstrated using a two-step refluxing and calcination process. First, a readily available inorganic salt, Ni(NO3)2⋅6H2O, used as the catalyst precursor was dissolved in the high-boiling-point organic solvents (alcohols or polyhydric alcohol) by refluxing at 190∘C for 3 hours. After refluxing, NiO nanoparticles obtained in the solution act as the catalyst, and the organic refluxing solvents are used as the carbon source for the growth of CNTs. Second, CNTs are prepared by calcining the refluxed solution at 800∘C in an N2 atmosphere for 3 hours. Results show that CNT growth possibly originates from carbon rings, with the nanotube walls growing perpendicular to these rings and forming a closed tube at the end

Phytoplankton community changes indicated by biomarker from sediment in Prydz Bay, Antarctica

Biomarkers including brassicasterol, dinosterol and alkenone in sediments are used as indicators to reconstruct changes to the phytoplankton community in surface and sub-aerial sediments of Prydz Bay, Antarctica. The results indicate that the biomarker records in surface and core sediment samples changed with time and space. The total content of phytoplankton biomarkers ranges from 391.0—1 470.6 ng∙g-1. The phytoplankton biomass has increased in Prydz Bay over the past 100 years. This variation may be mainly related with climate change in the region. The total biomarker contents in surface sediments from 5 stations in Prydz Bay are in the range of 215.8—1 294.3 ng∙g-1. The phytoplankton biomass in Prydz Bay is higher than that outside of the bay. This is similar to the distributions of chlorophyll a, organic carbon and biogenic silica in surface waters determined through in situ investigation. Such consistency indicates a coupling between the bottom of the ocean and biogeochemical processes in the upper water

Concentrations and distribution of biogenic barium in surface sediments of Prydz Bay, Antarctica

Concentrations of biogenic barium were investigated in surface sediments of Prydz Bay, Antarctica, during the 21st and 27th CHINARE cruises. Factors controlling the observed distribution are explored. Biogenic barium concentrations obtained from a sequential extraction procedure are compared with total concentrations obtained from the normative calculation based on a total digestion, and differences in the results are examined. Concentrations of biogenic barium, calculated by the normative calculation, were much higher than the concentrations obtained through sequential extraction; this discrepancy is the result of the occurrence of barium associated with Mn/Fe oxides, which represents an important component of total barium in these sediments. Concentrations of biogenic barium obtained from the sequential extraction range from 104 to 445 μg∙g-1, and the average concentration was 227 μg∙g-1. The highest concentrations of biogenic barium occur in the central area of the bay, where the seawater is more stable, while lower values occur in the bank and the ice shelf. Biogenic barium is significantly linearly correlated with biogenic barium and organic carbon, and similar in distribution of Chl a, which may indicate that primary productivity of phytoplankton in the surface water column is the main environmental factor regulating barium concentration and distribution