4,478 research outputs found
Control of the dipole layer of polar organic molecules adsorbed on metal surfaces via different charge-transfer channels
Organic molecules with a permanent electric dipole moment have been widely used as a template for further growth of molecular layers in device structures. Key properties of the resulting organic films such as energy level alignment (ELA), work function, and injection/collection barrier are linked to the magnitude and direction of the dipole moment at the interface. Using angle-resolved photoemission spectroscopy (ARPES), we have systematically investigated the coverage-dependent work function and spectral line shapes of occupied molecular energy states (MES) of chloroaluminium-phthalocyanine (ClAlPc) grown on Ag(111). We demonstrate that the dipole orientation of the first ClAlPc layer can be controlled by adjusting the deposition rate and post annealing conditions; the ELA at the interface differs by ~0.4 eV between the Cl-up and -down configurations of the adsorbed ClAlPc molecules. These observations are rationalized by density-functional-theory (DFT) calculations based on a realistic model of the ClAlPc/Ag(111) interface, which reveal that the different orientations of the ClAlPc dipole layer lead to different charge-transfer channels between the adsorbed ClAlPc and Ag(111) substrate. Our findings provide a useful framework towards method development for ELA tuning
The Application of Borehole Hydrogeological Investigation for Assessing Landslide Susceptibility
On the basis of 49 borehole studies at the mid- and upper-stream of the Dajia and Jhuoshuei river basins, landslide occurrence was found to not only be related to subsurface geological composition and hydrogeological characteristics, but also to groundwater level dynamics, which have seldom been addressed in previous works. It is suggested that the interplay between hydrogeologic and landslide factors be given further consideration in future investigations. This would be a crucial step towards effective disaster prevention for mountainous regions in Taiwan.本研究主要係嘗試透過孔內水文地質調查結果,評估大甲溪與濁水溪流域地表下岩層的地質材料特性、水力特性、地下水與集水區山崩潛勢之關聯性。過去研究較少針對崩塌地進行現地水文地質調查與試驗,本研究根據49處試驗場址成果顯示,水文地質特性與山崩的潛勢、滑動深度,以及地下水位有一定程度之關聯性。本研究建議進行調查區域的水文地質特性,以及各促崩因子所造成的山崩的易損性,係各類型山崩災害分析與潛勢評估之重要的研究各題,亦可提供相關台灣災害防治之參考
Will the US Economy Recover in 2010? A Minimal Spanning Tree Study
We calculated the cross correlations between the half-hourly times series of
the ten Dow Jones US economic sectors over the period February 2000 to August
2008, the two-year intervals 2002--2003, 2004--2005, 2008--2009, and also over
11 segments within the present financial crisis, to construct minimal spanning
trees (MSTs) of the US economy at the sector level. In all MSTs, a core-fringe
structure is found, with consumer goods, consumer services, and the industrials
consistently making up the core, and basic materials, oil and gas, healthcare,
telecommunications, and utilities residing predominantly on the fringe. More
importantly, we find that the MSTs can be classified into two distinct,
statistically robust, topologies: (i) star-like, with the industrials at the
center, associated with low-volatility economic growth; and (ii) chain-like,
associated with high-volatility economic crisis. Finally, we present
statistical evidence, based on the emergence of a star-like MST in Sep 2009,
and the MST staying robustly star-like throughout the Greek Debt Crisis, that
the US economy is on track to a recovery.Comment: elsarticle class, includes amsmath.sty, graphicx.sty and url.sty. 68
pages, 16 figures, 8 tables. Abridged version of the manuscript presented at
the Econophysics Colloquim 2010, incorporating reviewer comment
Optical observations of NEA 3200 Phaethon (1983 TB) during the 2017 apparition
The near-Earth asteroid 3200 Phaethon (1983 TB) is an attractive object not
only from a scientific viewpoint but also because of JAXA's DESTINY+ target.
The rotational lightcurve and spin properties were investigated based on the
data obtained in the ground-based observation campaign of Phaethon. We aim to
refine the lightcurves and shape model of Phaethon using all available
lightcurve datasets obtained via optical observation, as well as our
time-series observation data from the 2017 apparition. Using eight 1-2-m
telescopes and an optical imager, we acquired the optical lightcurves and
derived the spin parameters of Phaethon. We applied the lightcurve inversion
method and SAGE algorithm to deduce the convex and non-convex shape model and
pole orientations. We analysed the optical lightcurve of Phaethon and derived a
synodic and a sidereal rotational period of 3.6039 h, with an axis ratio of a/b
= 1.07. The ecliptic longitude (lambda) and latitude (beta) of the pole
orientation were determined as (308, -52) and (322, -40) via two independent
methods. A non-convex model from the SAGE method, which exhibits a concavity
feature, is also presented.Comment: 14 pages, 4 figures, 1 figure in Appendix A. Accepted for publication
in Astronomy & Astrophysics (A&A
Nanolithography : status and challenges
With the help of immersion lithography and multiple patterning, photolithography has been the key technology over the last decade in manufacturing of ICs, microchips and MEMS devices. Continuous rapid shrinking of feature size made the authorities to seek alternative patterning methods that can go beyond classic photographic limits. Some promising techniques have been proposed as next generation lithography and further technological progress are required to make them significant and reliable to meet the current demand. EUVL is considered as the main candidate for sub-10 nm manufacturing because of its process simplicity and reduced operating cost. Remarkable progress in EUVL has been made and the tools will be available for commercial operation soon. EBL, FIB and X-ray lithography are used for patterning in R&D, mask/mold fabrication and low volume chip design. DSA have already been realized in lab and further effort will be needed to make it as NGL solution. NIL has emerged attractively due to its simple process-steps, high-throughput, high-resolution and low cost and become one of the commercial platforms for nanofabrication
Investigation on viscosity and non-isothermal crystallization behavior of P-bearing steelmaking slags with varying TiO2 content
The viscous flow and crystallization behavior of CaO-SiO2-MgO-Al2O3-FetO-P2O5-TiO2 steelmaking slags have been investigated over a wide range of temperatures under Ar (High purity, >99.999 pct) atmosphere, and the relationship between viscosity and structure was determined. The results indicated that the viscosity of the slags slightly decreased with increasing TiO2 content. The constructed nonisothermal continuous cooling transformation (CCT) diagrams revealed that the addition of TiO2 lowered the crystallization temperature. This can mainly be ascribed to that addition of TiO2 promotes the formation of [TiO6]-octahedra units and, consequently, the formation of MgFe2O4-Mg2TiO4 solid solution. Moreover, the decreasing viscosity has a significant effect on enhancing the diffusion of ion units, such as Ca2+ and [TiO4]-tetrahedra, from bulk melts to the crystal–melt interface. The crystallization of CaTiO3 and CaSiTiO5 was consequently accelerated, which can improve the phosphorus content in P-enriched phase (n2CaO·SiO2-3CaO·P2O5). Finally, the nonisothermal crystallization kinetics was characterized and the activation energy for the primary crystal growth was derived such that the activation energy increases from −265.93 to −185.41 KJ·mol−1 with the addition of TiO2 content, suggesting that TiO2 lowered the tendency for the slags to crystallize
Elevated p62/SQSTM1 determines the fate of autophagy-deficient neural stem cells by increasing superoxide
Autophagy plays important roles in many biological processes, but our understanding of the mechanisms regulating stem cells by autophagy is limited. Interpretations of earlier studies of autophagy using knockouts of single genes are confounded by accumulating evidence for other functions of many autophagy genes. Here, we show that, in contrast to Fip200 deletion, inhibition of autophagy by deletion of Atg5, Atg16L1, or Atg7 does not impair the maintenance and differentiation of postnatal neural stem cells (NSCs). Only Fip200 deletion, but not Atg5, Atg16L1, or Atg7 deletion, caused p62/sequestome1 aggregates to accumulate in NSCs. Fip200 and p62 double conditional knockout mice demonstrated that p62 aggregate formation triggers aberrant superoxide increases by impairing superoxide dismutase functions. By comparing the inhibition of autophagy by deletion of Atg5, Atg16L1, or Atg7 with Fip200 deletion, we revealed a critical role of increased p62 in determining the fate of autophagy-deficient NSCs through intracellular superoxide control
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts
Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas
This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing
molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
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