Analysis and prevention of DRAM latch-up during power-on

The occasional power-on latch-up phenomenon of DRAM modules with a data bus shared by multiple DRAM chips on different modules was investigated and the circuit techniques for latch-up prevention were presented. Through HSPICE simulations and measurements, the latch-up triggering source was identified-to be the excessive voltage drop at the n-well pick-up of the CMOS transmission gate of read data latch circuit due to the short-circuit current which flows when the bus contention occurs during power-on. By extracting the HSPICE Gummel-Poon model parameters of the parasitic bipolar transistors of DRAM chips from the measured I-V and C-V data, HSPICE simulations were performed for the power-on latch-up phenomenon of DRAM chips. Good agreements were achieved between measured and simulated voltage waveforms. In order to prevent the power-on latch-up even when the control signals (RAS, GAS) do not track with the power supply, two circuit techniques were presented to solve the problem. One is to replace the CMOS transmission gate by a CMOS tristate inverter in the DRAM chip design and the other is to start the CAS-BEPORE-RAS (CBR) refresh cycle during power-on and thus disable all the Dout buffers of DRAM chips during the initial power-on period     

The production of macrophage inflammatory protein-1 alpha by human basophils

Macrophage inflammatory protein-1alpha (MIP-1alpha) has previously been shown to be produced by mononuclear cells, eosinophils, and neutrophils. Its production by basophils has not been investigated. The objective of this study was to investigate the production of MIP-1alpha by basophils. Peripheral blood basophils were separated by Percoll gradient centrifugation, cultured overnight, and processed for double immunocytochemistry using Abs against MIP-1alpha and FcepsilonRIalpha (alpha subunit of IgE receptor type 1). We demonstrated that basophils expressed immunoreactive MIP-1alpha upon stimulation with anti-IgE. Less than 5% of the basophils stained for MIP-1alpha without stimulation. The secretion of MIP-1alpha by basophils was studied by ELISA. In these experiments, basophils were further enriched to 65 to 99% (median, 86%) by a negative selection method. Basophils released MIP-1alpha when stimulated by Abs against IgE and FCepsilonRIalpha as well as IL-3 and the calcium ionophore, A23187. In parallel experiments, PBMC, eosinophils, and neutrophils did not produce MIP-1alpha in response to anti-IgE, but they did so in response to A23187. No MIP-1alpha release was detected in platelet preparations. Preincubation with IL-3 (15 min or 18 h) augmented anti-IgE-included basophil MIP-1alpha production. The secretion of MIP-1alpha by basophils was detectable shortly after stimulation and gradually increased over 24 h. Since MIP-1alpha has potent inflammatory and histamine-releasing activities, its production by basophils may indicate a positive feedback mechanism for allergic inflammation.     

A 1.8-V 128-Mb mobile DRAM with double boosting pump, hybrid current sense amplifier, and dual-referenced adjustment scheme for temperature sensor

To verify three important circuit schemes suitable for DRAMs in mobile applications, a 1.8-V 128-Mb SDRAM was implemented with a 0.15-/spl mu/m technology. To achieve an ideal 33% efficiency, the double boosting pump uses two capacitor's series connection at pumping phase, while they are precharged in parallel. The hybrid folded current sense amplifier together with a novel replica inverter connection improved power and speed performances. Also, a dual-referenced adjustment scheme for a temperature sensor was proposed to allow a very high accuracy in tuning. Without loss in productivity, the implemented dual-referenced searching technique achieved tuning error of less than /spl plusmn/2.5/spl deg/C.     

The optimization of conditions for the production of acid-hydrolysed winged bean and soybean proteins with reduction of 3-monochloropropane-1,2-diol (3-MCPD)

Response Surface Methodology (RSM) was used to establish the optimum time and temperature for production of acid‐hydrolysed winged bean protein (aHWBP) and acid‐hydrolysed soybean protein (aHSBP). Seven hours of hydrolysis at 125 °C was the optimum condition for producing aHWBP, whereas it was 5 h of hydrolysis at 125 °C for production of aHSBP. Although aHWBP and aHSBP produced using these conditions had favourable sensory qualities, they were found to have up to 25 mg kg^?1 of 3‐monochloropropane‐1,2‐diol (3‐MCPD). This exceeds the maximum level permissible in Commission Regulation (EC) No 466/2001. However, additional alkaline thermal treatment at pH 8.5 for 2 h at 100 °C effectively reduced the 3‐MCPD contents of aHWBP and aHSBP to undetectable levels. aHWBP has a distinctive flavour, which is different from that of aHSBP. The former has higher mean scores for meaty and vegetable attributes but lower mean scores for soy, umami and beany attributes than the latter.     

Ring sensor and heart rate monitoring system for sensor network applications

A ring-type pulse oximeter sensor attached to the finger and its 24-hour ambulatory heart rate monitoring system are presented. The PCB has been designed with a light-to-frequency converter and the CPU with a built-in Zigbee stack for simple and low power consumption. Also designed is the algorithm using a least square estimator to calibrate various signal distortions caused by motion artefacts for a proper accuracy.     

Selective Sharing of Load Current Components Among Parallel Power Electronic Interfaces in Three-phase Four-wire Stand-alone Microgrid

This paper investigates selective sharing of load current components among the parallel operation of distributed generators (DGs) in three-phase four-wire stand-alone microgrids. The proposed control method is based on master-slave operation of DGs, and the goal of selective sharing of load current components is to have DGs located in close proximity of the load operating in slave mode, in order to inject their available energy and also compensate the non-active load current components, while the distant DGs might operate in master mode to share the remaining load autonomously. Droop control is employed due to impracticality of communication at remote nodes, and resistive line impedance compensation is adopted to decouple active and reactive power controllers and ensure proper active power sharing among master DGs, irrespective of the mitigation of non-active current components by the slave inverters. The sharing factors for each current component are determined by a higher level control. The Conservative Power Theory (CPT) decompositions provide decoupled power and current references for the inverters, resulting in a selective sharing strategy. The principles supporting the developed control strategy are discussed, and the effectiveness of the control is demonstrated through computational simulations using PSIM software.     

Preparation of dandelion-type silica spheres and their application as catalyst supports

Dandelion-type silica spheres with a dendrimer-like porous structure were prepared by adding pore modifiers into aqueous synthetic mixtures of tetraethylorthosilicate (TEOS), hexadecyltrimethylammonium bromide (CTAB), ammonium hydroxide, and acetone. The formation of silica spheres and their porous characteristics were investigated using various techniques, including electron microscopy, nitrogen adsorption, and thermogravimetric analysis. Benzyl acetate (BENA) was very effective in the formation of a dendrimer-like porous structure. However, the composition of TEOS, CTAB, acetone, and BENA strongly influenced the size and shape of the silica spheres and their porous structure. The synthetic mixture of 1 TEOS: 0.22 CTAB: 1.9 BENA: 0.32 NH₄OH: 36 acetone: 236 H₂O produced dandelion-type silica spheres with diameters of ~300 nm. The phosphazenium hydroxide (PzOH) catalyst supported on the dandelion-type silica spheres prepared by adding BENA showed high catalytic performance in the transesterification of soybean oil with methanol due to its high feasibility for rapid access of large triglyceride molecules into the basic PzOH moieties incorporated in the pores.     

Microfluidic Design of Magnetoresponsive Photonic Microcylinders with Multicompartments

Colloidal photonic structures have been designed to have granular format to use them for paint pigments, encoded carriers, and display pixels. However, conventional approaches only provide spherical or discoid shapes, restricting their applications. Cylindrical granules with fan‐shaped compartments in the cross section are appealing for microcarriers with abundant optical codes and active display pigments for color switching. In this work, a stratified laminar flow of concentrated silica particles is employed, formed in a cylindrical microchannel, to produce cylindrical photonic microparticles with multiple compartments. To accomplish this, a microfluidic device is designed to have one cylindrical main channel connected with four branch channels. Four different photocurable suspensions are independently injected through the branches to form quarter‐cylindrically compartmentalized streams in the main channel. Local ultraviolet irradiation on the main channel polymerizes the suspension, thereby forming cylindrical microparticles with four compartments. In each compartment, silica particles form ordered array which develops particle size–dependent structural color. Therefore, different colors can be incorporated into single microcylinder by employing different sizes of silica particles. Moreover, one of the compartments can be rendered to be magnetoresponsive by embedding aligned magnetic particles, which enables the remote control of microcylinder orientation and therefore the switching of structural colors.