A New On-Land Seismogenic Structure Source Database from the Taiwan Earthquake Model (TEM) Project for Seismic Hazard Analysis of Taiwan

Taiwan is located at an active plate boundary and prone to earthquake hazards. To evaluate the island’s seismic risk, the Taiwan Earthquake Model (TEM) project, supported by the Ministry of Sciences and Technology, evaluates earthquake hazard, risk, and related social and economic impact models for Taiwan through multidisciplinary collaboration. One of the major tasks of TEM is to construct a complete and updated seismogenic structure database for Taiwan to assess future seismic hazards. Toward this end, we have combined information from pre-existing databases and data obtained from new analyses to build an updated and digitized three-dimensional seismogenic structure map for Taiwan. Thirty-eight on-land active seismogenic structures are identified. For detailed information of individual structures such as their long-term slip rates and potential recurrence intervals, we collected data from existing publications, as well as calculated from results of our own field surveys and investigations. We hope this updated database would become a significant constraint for seismic hazard assessment calculations in Taiwan, and would provide important information for engineers and hazard mitigation agencies

High-efficiency RNA cloning enables accurate quantification of miRNA expression by deep sequencing

Small RNA cloning and sequencing is uniquely positioned as a genome-wide approach to quantify miRNAs with single-nucleotide resolution. However, significant biases introduced by RNA ligation in current protocols lead to inaccurate miRNA quantification by 1000-fold. Here we report an RNA cloning method that achieves over 95% efficiency for both 5′ and 3′ ligations. It achieves accurate quantification of synthetic miRNAs with less than two-fold deviation from the anticipated value and over a dynamic range of four orders of magnitude. Taken together, this high-efficiency RNA cloning method permits accurate genome-wide miRNA profiling from total RNAs

Observation of interlayer phonon modes in van der Waals heterostructures

We have investigated the vibrational properties of van der Waals heterostructures of monolayer transition metal dichalcogenides (TMDs), specifically MoS2/WSe2 and MoSe2/MoS2 heterobilayers as well as twisted MoS2 bilayers, by means of ultralow-frequency Raman spectroscopy. We discovered Raman features (at 30 ~ 40 cm-1) that arise from the layer-breathing mode (LBM) vibrations between the two incommensurate TMD monolayers in these structures. The LBM Raman intensity correlates strongly with the suppression of photoluminescence that arises from interlayer charge transfer. The LBM is generated only in bilayer areas with direct layer-layer contact and atomically clean interface. Its frequency also evolves systematically with the relative orientation between of the two layers. Our research demonstrates that LBM can serve as a sensitive probe to the interface environment and interlayer interactions in van der Waals materials

Strength can be controlled by edge dislocations in refractory high-entropy alloys

Energy efficiency is motivating the search for new high-temperature (high-T) metals. Some new body-centered-cubic (BCC) random multicomponent “high-entropy alloys (HEAs)” based on refractory elements (Cr-Mo-Nb-Ta-V-W-Hf-Ti-Zr) possess exceptional strengths at high temperatures but the physical origins of this outstanding behavior are not known. Here we show, using integrated in-situ neutron-diffraction (ND), high-resolution transmission electron microscopy (HRTEM), and recent theory, that the high strength and strength retention of a NbTaTiV alloy and a high-strength/low-density CrMoNbV alloy are attributable to edge dislocations. This finding is surprising because plastic flows in BCC elemental metals and dilute alloys are generally controlled by screw dislocations. We use the insight and theory to perform a computationally-guided search over 10(7) BCC HEAs and identify over 10(6) possible ultra-strong high-T alloy compositions for future exploration

Spontaneous Arrangement of Two-way Flow in Water Bridge

By revisiting the century-old problem of water bridge, we demonstrate that it is in fact dynamic and comprises of two coaxial currents that carry different charges and flow in opposite directions. Initially, the inner flow is facilitated by the cone jet that is powered by H+ and flows out of the anode beaker. The negative cone jet from cathode is established later and forced to take the outer route. This spontaneous arrangement of two-way flow is revealed by the use of chemical dyes, e.g., fluorescein and FeCl3, carbon powder, and the Particle Image Velocimetry. These two opposing flows are found to carry non-equal flux that results in a net transport of water to the cathode beaker. By combining the above information and taking into account the counter flow to equate the water level from the connecting pipe, we can estimate the cross section and flow speed of these co-axial flows as a function of time and applied voltage.Comment: 5 pages, 5 figure

Trisodium bis­{1-[iminio­(morpholino)meth­yl]guanidinium} bis­[hexa­hydrogen­hexa­molybdoaluminate(III)] chloride icosa­hydrate

In the title compound, Na3(C6H15N5O)2[Al(OH)6Mo6O18]2Cl·20H2O, the [Al(OH)6Mo6O18]3− polyoxo­anion has a B-type Anderson structure exhibiting approximate D 3d symmetry. There are two types of sodium cations: the Na+ cations of type I have a distorted octa­hedral coordination geometry formed by six O atoms and are statistically distributed over two positions with equal occupancies, while the coordination polyhedra of the two Na+ cations of type II share one Cl anion located on an inversion center. The latter fragment, containing a Cl anion and two sodium cations, links two polyoxoanions into centrosymmetric blocks. The diprotonated 1-[imino­(morpholino)meth­yl]guanidinium cations and uncordinated water mol­ecules contribute to extensive N—H⋯O and O—H⋯O hydrogen bonding, resulting in the formation a three-dimensional supra­molecular structure

Earthquake Probability Assessment for the Active Faults in Central Taiwan: A Case Study

Frequent high seismic activities occur in Taiwan due to fast plate motions. According to the historical records the most destructive earthquakes in Taiwan were caused mainly by inland active faults. The Central Geological Survey (CGS) of Taiwan has published active fault maps in Taiwan since 1998. There are 33 active faults noted in the 2012 active fault map. After the Chi-Chi earthquake, CGS launched a series of projects to investigate the details to better understand each active fault in Taiwan. This article collected this data to develop active fault parameters and referred to certain experiences from Japan and the United States to establish a methodology for earthquake probability assessment via active faults. We consider the active faults in Central Taiwan as a good example to present the earthquake probability assessment process and results. The appropriate “probability model” was used to estimate the conditional probability where M ≥ 6.5 and M ≥ 7.0 earthquakes. Our result shows that the highest earthquake probability for M ≥ 6.5 earthquake occurring in 30, 50, and 100 years in Central Taiwan is the Tachia-Changhua fault system. Conversely, the lowest earthquake probability is the Chelungpu fault. The goal of our research is to calculate the earthquake probability of the 33 active faults in Taiwan. The active fault parameters are important information that can be applied in the following seismic hazard analysis and seismic simulation

Observation of Interlayer Phonon Modes in van der Waals Heterostructures

We have investigated the vibrational properties of van der Waals heterostructures of monolayer transition metal dichalcogenides (TMDs), specifically MoS2/WSe2 and MoSe2/MoS2 heterobilayers and twisted MoS2 bilayers, by means of ultralow-frequency Raman spectroscopy. We discovered Raman features (at 30–40 cm−1) that arise from the layer-breathing mode (LBM) vibration between the two incommensurate TMD monolayers in these structures. The LBM Raman intensity correlates strongly with the suppression of photoluminescence that arises from interlayer charge transfer. The LBM is generated only in bilayer areas with direct layer-layer contact and an atomically clean interface. Its frequency also evolves systematically with the relative orientation between the two layers. Our research demonstrates that the LBM can serve as a sensitive probe to the interface environment and interlayer interactions in van der Waals materials