ALBERT

Description: The fabrication and electrical characterization of Schottky junction diodes have been extensively researched for three-quarters of a century since the original work of Schottky in 1938. This study breaks from the highly standardized regime of such research and provides an alternative methodology that prompts novel, more efficient applications of the adroit Schottky junction in areas such as chemical and thermal sensing. The core departure from standard Schottky diode configuration is that the metal electrode is of comparable or higher resistance than the underlying semiconductor. Further, complete electrical characterization is accomplished through recording four-probe resistance-temperature ( R D -T ) characteristics of the device, where electrical sourcing and sensing is done only via the metal electrode and not directly through the semiconductor. Importantly, this results in probing a nominally unbiased junction while eliminating the need for an Ohmic contact to the semiconductor. The characteristic R D -T plot shows two distinct regions of high (metal) and low (semiconductor) resistances at low and high temperatures, respectively, connected by a cross-over region of width, ΔT , within which there is a large negative temperature coefficient of resistance. The R D -T characteristic is highly sensitive to the Schottky barrier height; consequently, at a fixed temperature, R D responds appreciably to small changes in barrier height such as that induced by absorption of a chemical species (e.g., H 2 ) at the interface. A theoretical model is developed to simulate the R D -T data and applied to Pd/p-Si and Pt/p-Si Schottky diodes with a range of metal electrode resistance. The analysis gives near-perfect fits to the experimental R D -T characteristics, yielding the junction properties as fit parameters. The modelling not only helps elucidate the underlying physics but also helps to comprehend the parameter space essential for the discussed applications. Although the primary regime of application is limited to a relatively narrow range ( ΔT ) for a given type of diode, the alternative methodology is of universal applicability to all metal-semiconductor combinations forming Schottky contacts.

Description: Predicting the propagation path of a network worm is highly beneficial for taking appropriate countermeasures in advance. Traditional worm propagation models mainly deal with the total number of infected hosts during a period of time, which cannot indicate a worm's track. We choose the worm using random scanning to study, as it was the basic type and all the others were derived from it. A novel model proposed in this paper locates the subnets going to be infected at a given time based on the infection measurement of the subnet. The time and frequency for victims in the subnet to increase were calculated according to common characteristics of worm diffusion and the relationship between malicious traffic and bandwidth usage. Taking the two factors above as input, fuzzy reasoning was adopted to deduce the real-time infection situation for each subnet. The bigger the value of infection situation, the more likely the corresponding subnet would be attacked in a short time. Simulation experimental results show that the model estimates the worm's track dynamically with acceptable accuracy. Furthermore, the increase interval of victims in subnet is much longer for worm with slower spread speed, which provides sufficient time to carry out pertinent response.

Description: Rice wine fermentation represents a unique environment for the evolution of the budding yeast, Saccharomyces cerevisiae . To understand how the selection pressure shaped the yeast genome and gene regulation, we determined the genome sequence and transcriptome of a S. cerevisiae strain YHJ7 isolated from Chinese rice wine (Huangjiu), a popular traditional alcoholic beverage in China. By comparing the genome of YHJ7 to the lab strain S288c, a Japanese sake strain K7, and a Chinese industrial bioethanol strain YJSH1, we identified many genomic sequence and structural variations in YHJ7, which are mainly located in subtelomeric regions, suggesting that these regions play an important role in genomic evolution between strains. In addition, our comparative transcriptome analysis between YHJ7 and S288c revealed a set of differentially expressed genes, including those involved in glucose transport (e.g., HXT 2, HXT7 ) and oxidoredutase activity (e.g., AAD 10, ADH 7). Interestingly, many of these genomic and transcriptional variations are directly or indirectly associated with the adaptation of YHJ7 strain to its specific niches. Our molecular evolution analysis suggested that Japanese sake strains (K7/UC5) were derived from Chinese rice wine strains (YHJ7) at least approximately 2,300 years ago, providing the first molecular evidence elucidating the origin of Japanese sake strains. Our results depict interesting insights regarding the evolution of yeast during rice wine fermentation, and provided a valuable resource for genetic engineering to improve industrial wine-making strains.

Description: This article concerns tests for sphericity in cases where the data dimension is larger than the sample size. The existing multivariate sign-based procedure (Hallin & Paindaveine, 2006) for sphericity is not robust with respect to high dimensionality, producing tests with Type I error rates that are much larger than the nominal levels. This is mainly due to bias from estimating the location parameter. We develop a correction that makes the existing test statistic robust with respect to high dimensionality, and show that the proposed test statistic is asymptotically normal under elliptical distributions. The proposed method allows the dimensionality to increase as the square of the sample size. Simulations demonstrate that it has good size and power in a wide range of settings.

Description: Two novel core–shell structure ternary terbium composites SiO 2(600) @Tb(MABA-Si)·L(L:dipy/phen) nanometre luminescence materials were prepared by ternary terbium complexes Tb(MABA-Si)·L 2 ·(ClO 4 ) 3 ·2H 2 O shell grafted onto the surface of SiO 2 microspheres. And corresponding ternary terbium complexes were synthesized using (CONH(CH 2 ) 3 Si(OCH 2 CH 3 ) 3 ) 2 (denoted as MABA-Si) as first ligand and L as second ligand coordinated with terbium perchlorate. The as-synthesized products were characterized by means of IR spectra, 1 HNMR, element analysis, molar conductivity, SEM and TEM. It was found that the first ligand MABA-Si of terbium ternary complex hydrolysed to generate the Si–OH and the Si–OH condensate with the Si–OH on the surface of SiO 2 microspheres; then ligand MABA-Si grafted onto the surface of SiO 2 microspheres. The diameter of SiO 2 core of SiO 2(600) @Tb(MABA-Si)·L was approximately 600 nm. Interestingly, the luminescence properties demonstrate that the two core–shell structure ternary terbium composites SiO 2(600) Tb(MABA-Si)·L(dipy/phen) exhibit strong emission intensities, which are 2.49 and 3.35 times higher than that of the corresponding complexes Tb(MABA-Si)·L 2 ·(ClO 4 ) 3 ·2H 2 O, respectively. Luminescence decay curves show that core–shell structure ternary terbium composites have longer lifetime. Excellent luminescence properties enable the core–shell materials to have potential applications in medicine, industry, luminescent fibres and various biomaterials fields.

Description: Author(s): X. H. Niu, R. Peng, H. C. Xu, Y. J. Yan, J. Jiang, D. F. Xu, T. L. Yu, Q. Song, Z. C. Huang, Y. X. Wang, B. P. Xie, X. F. Lu, N. Z. Wang, X. H. Chen, Z. Sun, and D. L. Feng To understand the pairing symmetry and superconducting transition temperature in heavily electron-doped iron-based superconductors, it is important to study more of these materials, especially ones with decent stability in air and without phase separation. Here, angle-resolved photoemission spectroscopy probes the surface electronic structure and superconducting gap in the new superconductor (Li 0 . 8 Fe 0 . 2 )OHFeSe, which shows a T c as high as 40 K. [Phys. Rev. B 92, 060504(R)] Published Tue Aug 18, 2015

Description: Recent advances in materials, mechanics, and electronic device design are rapidly establishing the foundations for health monitoring technologies that have "skin-like" properties, with options in chronic (weeks) integration with the epidermis. The resulting capabilities in physiological sensing greatly exceed those possible with conventional hard electronic systems, such as those found in wrist-mounted wearables, because of the intimate skin interface. However, most examples of such emerging classes of devices require batteries and/or hard-wired connections to enable operation. The work reported here introduces active optoelectronic systems that function without batteries and in an entirely wireless mode, with examples in thin, stretchable platforms designed for multiwavelength optical characterization of the skin. Magnetic inductive coupling and near-field communication (NFC) schemes deliver power to multicolored light-emitting diodes and extract digital data from integrated photodetectors in ways that are compatible with standard NFC-enabled platforms, such as smartphones and tablet computers. Examples in the monitoring of heart rate and temporal dynamics of arterial blood flow, in quantifying tissue oxygenation and ultraviolet dosimetry, and in performing four-color spectroscopic evaluation of the skin demonstrate the versatility of these concepts. The results have potential relevance in both hospital care and at-home diagnostics.

Description: Cardiac progenitor cell-derived exosomes prevent cardiomyocytes apoptosis through exosomal miR-21 by targeting PDCD4 Cell Death and Disease 7, e2277 (June 2016). doi:10.1038/cddis.2016.181 Authors: J Xiao, Y Pan, X H Li, X Y Yang, Y L Feng, H H Tan, L Jiang, J Feng & X Y Yu

Description: Author(s): X. P. Shen, S. D. Chen, Q. Q. Ge, Z. R. Ye, F. Chen, H. C. Xu, S. Y. Tan, X. H. Niu, Q. Fan, B. P. Xie, and D. L. Feng We studied the low-lying electronic structure of the newly discovered iron-platinum-arsenide superconductor, Ca 10 (Pt 4 As 8 )(Fe 2− x Pt x As 2 ) 5 ( T c =22 K) with angle-resolved photoemission spectroscopy. We found that the Pt 4 As 8 layer contributes to a small electronlike Fermi surface, indicative of metallic c... [Phys. Rev. B 88, 115124] Published Fri Sep 13, 2013

Description: Author(s): Juan Jiang (姜娟), C. He (贺诚), Y. Zhang (张焱), M. Xu (徐敏), Q. Q. Ge (葛青亲), Z. R. Ye (叶子荣), F. Chen (陈飞), B. P. Xie (谢斌平), and D. L. Feng (封东来) The in-plane resistivity anisotropy has been studied with the Montgomery method on the detwinned parent compound of the iron-based superconductor FeTe. The observed resistivity in the antiferromagnetic (AFM) direction is larger than that in the ferromagnetic (FM) direction, which is different from t... [Phys. Rev. B 88, 115130] Published Tue Sep 17, 2013