Four-port Switch Research Articles

Employing a switching valve to automate external standard calibration in inductively coupled plasma optical emission spectrometry

The traditional external standard calibration method (EC) is automated and simplified using a four-port switching valve (SV4) and a multi-signal approach that enables the generation of several calibration points from a single calibration solution. The SV4-EC method is applied to inductively coupled plasma optical emission spectrometry (ICP-OES) and is based on gradient dilution taking place within the instrument's sample introduction tubing. Both the calibration solution and the samples are diluted by a blank solution containing an internal standard species. Forty-five dilution points are collected over time while the solutions are mixed. Instrument responses from the calibration solution are then plotted against those from the samples, and the slope of the calibration curve is used to determine the unknown analyte concentrations in the samples. The method is used to determine Ba, Co, Cr, Cu, Fe, Mn, Ni, V and Zn in coconut water, creek water, green tea, mouthwash, soft drink, vinegar, and vodka. Limits of detection are in the 0.0002–0.009 mg L−1 (n = 10) range, with precision on the order of 0.4 %–3 % RSD. Analyte percent recoveries from a 0.5 mg L−1 spike are in the ranges of 88.4 %–111 %, 88.9 %–111 %, and 88.0 %–111 % for EC, SV4-EC, and the internal-standard-corrected method (SV4-EC/Sc), respectively. No statistically significant difference is observed between EC and SV4-EC recoveries for any of the sample matrices evaluated. Comparable results between EC and SV4-EC were also found for the analysis of two certified reference materials, Bovine Liver and Oyster Tissue. Based on a single calibration solution, the SV4-EC method requires caution when preparing the calibration standard to minimize measurement bias.

Automated standard dilution analysis using a four-port switching valve for fast inductively coupled plasma optical emission spectrometry determination

A four-port switching valve (SV4) autonomously mix the two calibration solutions in standard dilution analysis for fast and accurate ICP-OES analysis of complex matrices.

Online coupling solid-phase ligand-fishing with high-performance liquid chromatography-diode array detector-tandem mass spectrometry for rapid screening and identification of xanthine oxidase inhibitors in natural products.

Screening and analysis of bioactive compounds from natural products is challenging work due to their complexity. This study presents the first report on hyphenation of solid-phase ligand-fishing using immobilized xanthine oxidase microcolumn (IXOM) and high-performance liquid chromatography-diode array detector-tandem mass spectrometry (HPLC-DAD-MS/MS) for screening and identification of XO inhibitors from complex mixtures. Solid-phase ligand-fishing system was hyphenated withthe HPLC system via four-port switching valve and a six-port injection valve as an interface for transferring effluents from IXOM to HPLC, and collecting chromatograms from LFMC (ligand-fishing microextraction column) and C18 column in a run by only one DAD. Mixtures containing allopurinol (positive control) and tryptophane (negative control) were analyzed in order to verify the specificity and reproducibilityof the approach. Subsequently, the newly developed system was applied to screening and identification of XO inhibitors from L. macranthoides and its human microsomal metabolites. Six prototype compounds (3-caffeoylquinic acid, 5-caffeoylquinic acid, 4-caffeoylquinic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid) and three metabolites (3-caffeoyl-epi-quinic acid, 5-caffeoyl-epi-quinic acid, 4-caffeoyl-epi-quinic acid) with XO binding affinities were identified. The XO inhibition activities of six prototype compounds were evaluated and confirmed using in vitro enzymatic assay. With the online system developed here, we present a feasible, selective, and effective strategy for rapid screening and identification of enzyme inhibitors from complex mixtures.

Mach–Zehnder-Based Four-Port Switching Module on SOI

In this letter, a Mach-Zehnder-based four-port switching module was designed and fabricated by a 0.8-μm standard commercial complementary metal-oxide semiconductor line. The module is composed of five electro-optic switching elements and can be used to realize nonblocking switching for the duplex interconnection among four ports. The switching elements are electrically driven with a nanosecond response. Full routing functionality of the four-port switching module is demonstrated with crosstalk levels lower than -11.8 dB under a common spectral bandwidth of 40 nm.

Switching Characteristics in Variable-Index Arrayed Waveguides Using Thin-Film Heater

We have demonstrated switching characteristics in a wavelength switch based on multiple GaInAs/InP quantum wells. It consisted of straight arrayed waveguides with a linearly varying refractive index distribution. The refractive index can be changed via the thermo-optic (TO) effect. Using a Ti/Au thin-film heater to generate the TO effect, we realized four-port switching at four demultiplexed wavelengths. In addition, by changing the structure of the heater from rectangular to triangular, the power consumption for four-port switching was reduced by half.

Integrated Row and Column Rerouting for Reconfiguration of VLSI Arrays with Four-Port Switches

This paper deals with the issue of developing efficient algorithms for reconfiguring two-dimensional VLSI arrays linked by four-port switches in the presence of faulty processing elements (PEs). The proposed algorithm reroutes the arrays with faults in both row and column directions at the same time. Unlike previous work, the compensation technique to replace the faulty PE is not restricted to the adjacent rows of the excluded row. Instead, we consider the neighbor rows of any faulty PE for compensation purposes. The nonfaulty PEs lying in the excluded rows are also effectively utilized to form the maximal target arrays, making the proposed algorithm more efficient in terms of both the percentages of harvest and the degradation of VLSI arrays for random and clustered faults. Empirical study shows that the improvement in harvest increases with increasing fault size and is more notable for maximal square target arrays than for maximal target arrays. Our investigations show that the improvement can be up to 8 percent and 23 percent for a 256 times 256 VLSI array with random faults of size 25 percent for maximal target arrays and for maximal square target arrays, respectively.

Reconfiguration algorithms for power efficient VLSI subarrays with four-port switches

Techniques to determine subarrays when processing elements of VLSI arrays become faulty have been investigated extensively. These tend to identify the largest subarray that is possible without concentrating on the power efficiency of the resulting subarray. In this paper, we propose new techniques, based on heuristic strategy and dynamic programming, to minimize the interconnect length in an attempt to reduce power dissipation without performance penalty. Our algorithms show that notable improvements in the reduction of the number of long interconnects could be realized in linear time and without sacrificing the size of the subarray. Our evaluations show that, for a VLSI array of size 256/spl times/256, the number of long interconnects in the subarray can be reduced by up to 95 percent for clustered faults and up to 50 percent and 73 percent for a random fault with density of 10 percent and 0.1 percent, respectively, when compared with the most efficient implementation cited in the literature. The interconnect power saving for a VLSI array of size 512/spl times/512 is by up to 11 percent for a random fault. We have also shown that interconnect power savings of up to 14 percent are possible for the cases investigated. Simulations based on several random and clustered fault scenarios clearly reveal the superiority of the proposed techniques for power efficient realizations. In addition, the lower bound of the performance has been proposed to demonstrate that the proposed algorithms are nearly optimal for the cases considered in this paper.

SCI evaluation in multinode environments for computing and data-processing applications

The need of high-performance low-cost computing systems motivates intense research in this field, and some very fine results have been achieved. By clustering cheap personal computers together, we placed a virtual supercomputer at our disposal. Currently, PC clusters are mainly programmed using message passing programming models. The scalable coherent interface (SCI) interconnect technology opens the possibility for shared memory models. To profit from all the advantages that SCI offers, an application programming interface (API) for SCI-based systems is needed. The SISCI API provides the necessary tools for developing SCI-based systems applications like performance tests and other similar utilities. The paper presents an easy application that uses the SCI API functions and was developed to measure the total bandwidth of a cluster. Four PCs with Pentium II and running under a Windows NT 4.0 server were connected via Dolphin's four-port switch. The application is an example of what this SCI API can offer to any user who wants to develop an SCI-based cluster application without the need of a wide knowledge on the SCI standard.

InGaAsP/InP optical waveguide switch operated by a carrier-induced change in the refractive index

Waveguided semiconductor optical switches operated by a carrier-induced change in the refractive-index associated with the plasma dispersion are proposed. InGaAsP/InP four-port switches having two intersecting single-mode channel waveguides are fabricated by selective liquid-phase epitaxy and investigated at 1.5μm wavelength. Optical switching is observed as a result of mode interference in the waveguide intersection region.

Waveguided optical switch in InGaAs/InP using free-carrier plasma dispersion

Waveguided optical switches using a carrier injection plasma dispersion are proposed. InGaAsP/InP four-port switches with two intersecting single-mode channel waveguides were fabricated by selective LPE and investigated at 1.5 μm wavelength. Optical switching was observed, based on mode interference in the waveguide intersecting region.

Liquid-crystal fiber-optic switch

An adjustable access coupler for multimode fiber-optic networks has been constructed, based on the voltage-tunable total-internal-reflection effect in nematic liquid crystals. Fibers are coupled via graded-index rod lenses at normal incidence to flint-glass prisms in contact with a 6-microm liquid-crystal layer. The achromatic four-port switch has a 1.6-dB optical insertion loss, a tap ratio controllable from -4.6 to -48 dB, a directionality of 44 dB, and an operating voltage of 5 to 20 V rms.

Compound optical crosspoint with low crosstalk

A multimode electrooptical switch that has high isolation between channels has been demonstrated experimentally in a 70-microm-thick plate of Z-cut LiTaO(3). The fiber-compatible four-port switch is intended for integration into an optical matrix. The crosspoint consists of an in-plane crossover, two simple optical switches, and a curved connecting waveguide. For convergent input light with a 0.07 numerical aperture, 10% of the initially channeled light was transferred into the crosschannel, and the optical switching ratio of that channel was 26 dB using 450-V dc for control.