A novel simple CBCM method free from charge injection-induced errors

In this letter, we propose a charge injection-induced error-free charge-based capacitance measurement method (CIEF CBCM). This novel method uses only one n/pMOS pair to characterize the small interconnect capacitance. It has the simplest test structure among various CBCM methods. More importantly, the CIEF CBCM method is free from the errors induced by charge injection. Besides, only one additional pad is needed for one additional capacitor under the test by this method, and it is the most efficient method for process characterization and monitoring.     

Desorption ionization of biomolecules on metals

Direct desorption ionization of various types of biomolecules on metal substrates without the need of matrices was observed by a time-of-flight mass spectrometer. It provides a new convenient method for detection of small biomolecules without the confusion of ion peaks from matrix compounds. Simple commercial Al foil can be used as the substrate to obtain mass spectra of biomolecules without the need of an etching process to produce a porous surface such as with direct ionization on silicon (DIOS). The desorption and ionization mechanism is also discussed.     

Bipolar ion detector based on sequential conversion reactions

This work demonstrates the feasibility of a novel scintillation detector with greater detection efficiency than that of chevron-type microchannel plate (MCP) detectors. The detection mechanism involves sequential conversion reactions induced by ion-surface impacts. Identical detection conditions can be utilized to monitor both positive and negative ions in mass spectrometers. The proposed detector comprises an ion beam guiding device, a negatively biased washer-shaped conversion dynode, and an aluminum-coated scintillation detector. The beam guide changes the electric field around the washer-shaped conversion dynode, and it allows the primary and secondary ions to propagate toward the scintillation phosphor and the conversion dynode, respectively. The detection is achieved by the detection of electron-induced luminescence on a phosphor. The amplification efficiency of this bipolar ion detector increases as the conversion dynode voltage increases. For ions with a mass-to-charge ratio of up to 90 000, the sensitivity of the BID is 1.4-14.4 times that of the MCP. Further improvement of the sensitivity can be achieved by increasing the conversion dynode voltage or the ion acceleration voltage. Results of this study demonstrate that this detector is a promising alternative for efficient ion detection.     

High-speed mass measurement of nanoparticle and virus

Until now, there have been no relatively easy methods to measure the mass and mass distributions of nanoparticles/viruses. In this work, we report the first set of measurements of mass and mass distributions for nanoparticles/viruses using a novel mass spectrometry technology. In the past, mass spectrometry was typically used to measure the mass of a particle or molecule with a mass less than 1,000,000 Da. We developed cell mass spectrometry that can measure the mass of a cell or a microparticle. Nevertheless, there is a gap for mass measurement methods in the mass region of a nanoparticle or virus (1 MDa to 1 GDa). Here, we developed a nanoparticle/virus mass spectrometry technique to make rapid and accurate mass and mass distribution measurements of nanoparticles/viruses. This technique should be valuable for the quality control of nanoparticle production and the identification of various viruses. In the future, this method can also serve to monitor drug delivery when nanoparticles are used as carriers. Furthermore, it may be possible to measure the degree of infection by measuring the number of viruses in specific cells or in plasma.     

Rapid Identification of Terminal Sialic Acid Linkage Isomers by Pseudo-MS3 Mass Spectrometry

We used pseudo-triple-stage tandem MS to rapidly differentiate terminal α(2,3)- and α(2,6)-linked sialic acids of glycopeptides and native glycans. The precursor ions generate important diagnostic fragments to distinguish different terminal linked isomeric glycans and glycopeptides based on collision-induced dissociation (CID). The diagnostic ions include hexose linked with N-acetylhexosamine residues, sialic acid with the loss of water, and sialic acid residues. Their values of mass-to-charge ratio (m/z) are at 366.14, 274.09, and 292.10, respectively. The relative intensity ratios (RIR) were calculated by the intensity of signals at m/z 274.09 and 292.10 divided by the intensity of the signal at m/z 366.14. Under optimal conditions of an in-source fragmentation voltage of 70 V and a normalized collision energy of 30 %, the difference in RIR of diagnostic ions between terminal α(2,3)-linked sialic acid of glycopeptide (1.3) and terminal α(2,6)-linked sialic acid of glycopeptide (<0.18) is the largest. Moreover, quantitative calibration curves with different percentages of α(2,3)- and α(2,6)-linked sialoglycopeptides demonstrated that this method applied not only to biantennary N-linked glycan, but also to complex and hybrid N-linked glycans and O-linked glycans. From measurements of the RIR of diagnostic ions, erythropoietin, fetuin, and herceptin have 98, 70, and 100 %, respectively, α(2,3)-linked N-sialic acid of total terminal sugar moieties. N-Glycosylation of the antibody-binding fragment (Fab) moiety of cetuximab has 100 % α(2,6)-linked N-glycolylneuraminic acid terminal glycan linkages. This method can be applied to identify compounds from chemical synthesis. It can also be used for quality evaluation of bio-similar protein drugs.     

A unified structure of trellis-based soft-output decoding algorithms for turbo codes

In this paper, a general reliability-updating formula is proposed for trellis-based soft-output decoding algorithms to optimize the tradeoff between performance and complexity. Based on the general formula, new algorithms are presented, and a concise interpretation is provided to relate new proposed algorithms and those reported previously. In addition, we devise a unified decoding structure with respect to the general formula. All trellis-based algorithms are mapped into a single decoding process under the unified structure, and different algorithms can be easily switched between one another. Owing to the modularity and flexibility, this unified structure is especially suitable for turbo decoders with programmable implementation.     

Bilateral exchange of soft-information for iterative reliability-based decoding with adaptive belief propagation

For linear block codes without a sparse graph representation, there exists an iterative decoding algorithm which combines the traditional reliability-based decoding (RBD) with adaptive belief propagation (ABP) to achieve a good tradeoff between the error performance and decoding complexity. However, in the original design of the iterative scheme, only a one-way flow of soft-information from the ABP-part to the RBD-part is available, hence limiting the performance of iterative processing. In this study, several low-complexity schemes are presented for the RBD-part to produce desirable soft-outputs such that decoded results can be bilaterally exchanged between both of the RBD and ABP parts. Simulation results also verify the superiority of the proposed idea over the conventional design.     

Kinetics of proton-excited Ar-F2and Kr-F2mixtures

Mixtures of Ar and F2and of Kr and F2were excited with pulsed proton beams. Time-resolved spectra as well as time-integrated spectra were employed to study the detailed mechanism of production and quenching processes of ArF*, KrF*, Ar2F*, and Kr2F*. The kinetics of ArF*, KrF*, and XeF* lasers are discussed briefly.     

Charge monitoring cell mass spectrometry

An instrument to directly measure the charge carried by a cell or a microparticle as well as mass-to-charge ratio of the cell/microparticle was developed for rapid mass distribution measurement. A successful mass spectrum with a record high mass has been demonstrated. In this article, the details of the construction and operation of the charge monitoring cell mass spectrometer are reported. Examples are also given for demonstration and discussion.     

Combined puncturing and path pruning for convolutional codes and the application to unequal error protection

In this paper, puncturing and path pruning are combined for convolutional codes to construct a new coding scheme for unequal error protection (UEP), called the hybrid punctured and path-pruned convolutional codes. From an algebraic viewpoint, we show that the hybrid codes not only inherit all the advantages of the conventional rate-compatible punctured convolutional codes and path-compatible pruned convolutional codes but also can provide more flexible choices of protection capability for UEP. In addition, a data-multiplexing scheme originally proposed for path-pruned codes which can guarantee smooth transition between rates without additional zero-padding for frame termination is proven applicable to the hybrid codes to improve the system throughput.