Dynamic optimization methodology based on subgrid-scale dissipation for large eddy simulation

A dynamic procedure based on subgrid-scale dissipation is proposed for large eddy simulation of turbulent flows. In the new method, the model coefficients are determined by minimizing the square error of the resolved dissipation rate based on the Germano identity. A dynamic two-term mixed model is tested and evaluated both a priori and a posteriori in simulations of homogeneous and isotropic turbulence. The new dynamic procedure proves to be more effective to optimize the model coefficients as compared with traditional method. The corresponding dynamic mixed model can predict the physical quantities more accurately than traditional dynamic mixed model. (C) 2016 AIP Publishing LLC

Physiological Responses of Synechocystis sp PCC 6803 under Clinorotation

Photosystem efficiency and the characteristic on oxidative stress were examined to elucidate the metabolic responses of Synechocystis sp. PCC 6803 to short-term clinorotation. Results compiled when using clinostat to simulate microgravity for 60 h, showed that clinorotation clearly prohibited the photochemical quantum yield, but promoted the synthesis of chlorophyll and total protein. This may be a compensatory mechanism for the algal cell to maintain its normal metabolism. An increased malondialdehyde (MDA) content of algal cell upon clinorotation, together with an enhanced catalase (CAT) activity was observed during the whole period of clinorotation. One conclusion is that short-term clinorotation acts as a kind of stress, and that these physiological responses may be a special way for an algal cell to adapt itself to a different environment other than earth gravity.Photosystem efficiency and the characteristic on oxidative stress were examined to elucidate the metabolic responses of Synechocystis sp. PCC 6803 to short-term clinorotation. Results compiled when using clinostat to simulate microgravity for 60 h, showed that clinorotation clearly prohibited the photochemical quantum yield, but promoted the synthesis of chlorophyll and total protein. This may be a compensatory mechanism for the algal cell to maintain its normal metabolism. An increased malondialdehyde (MDA) content of algal cell upon clinorotation, together with an enhanced catalase (CAT) activity was observed during the whole period of clinorotation. One conclusion is that short-term clinorotation acts as a kind of stress, and that these physiological responses may be a special way for an algal cell to adapt itself to a different environment other than earth gravity

Biphenyls from aerial parts of Ribes takare

Three new biphenyls, 4,7,8-trimethoxy-2,3-methylenedioxydibenzofuran (1), 7-hydroxy-4,8dimethoxy-2,3-methylenedioxydibenzofuran (2), and 3',5-dimethoxy-3,4-methylenedioxybiphenyl (3), along with eighteen known compounds (4-21) were isolated from the aerial part of Ribes takare D. Don. Their structures were elucidated on the basis of spectroscopic data. Compound 1 and compound 2 showed mild alpha-glucosidase inhibitory activity. (C) 2013 Guo-You Li and Dong-Mei Fang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Interaction-induced supercurrent in quantum Hall setups

Recently, we have proposed an unusual mechanism of superconducting current that is specific for quantum Hall edge channels connected to superconducting electrodes. We have shown that the supercurrent can be mediated by a nonlocal electron-electron interaction that provides an opportunity for a long-distance information transfer in the direction opposite to the electron flow. A convenient model for such interaction is that of an external circuit. The consideration has been performed for the case of a single channel. In order to facilitate the experimental verification and the observation of peculiar features of the effect, in this paper, we provide a more detailed description of the phenomenon and extend the results to more sophisticated setups. We establish that the dynamical phase contributes to superconducting interference; this being the manifestation of the channel chirality. We consider setups that include the scattering between quantum Hall channels of opposite direction and multiple superconducting contacts. For a single quantum Hall constriction, we derive a general and comprehensive relation for the interaction-induced supercurrent in terms of scattering amplitudes and demonstrate the nonlocal nature of the current by considering its sensitivity to scattering. In multiterminal setups, we reveal the characteristic phase dependences of the supercurrents explaining those in terms of interference of Andreev reflection processes. For more complex setups encompassing, at least, two constrictions, we find an interplay between noninteracting and interaction-induced currents and contributions of more complex interference processes.QN/Nazarov Grou

Topology protection-unprotection transition: Example from multiterminal superconducting nanostructures

We show theoretically that in the superconducting nanostructures the gapped states of different topology are not always protected by separating gapless states. Depending on the structure design parameters, they can be either protected or not, with a protection-unprotection transition separating these two distinct situations. We build up a general theoretical description of the transition vicinity in the spirit of Landau theory. We speculate that similar protection-unprotection transitions may also occur for other realizations of topological protection in condensed matter systems.QN/Nazarov Grou

Finite Element Analysis of Power Module Packages with One-step Molding for Power Inductors

With the development of 5G communication technology and the rise of power semiconductors, the switching frequency of the circuit keeps increasing, which pushes for miniaturization of power modules and related components. Therefore, in this paper, a one-step molding technology was proposed for a DC/DC buck converter power module. We proposed a method of using Soft Magnetic Powder filled Epoxy (SMPE) adhesive as a molding material to encapsulate a power module, which is a DC/DC buck converter power module contains several passive components, 1 power inductor, and a high-efficiency switching regulator with two integrated N-channel MOSFETs. On the basis of Finite Element Method (FEM), models were firstly established with component level moldings and checked with actual module samples for calibration. Based on the calibrated model, inductors without component level molding were then simulated. SMPE with 4~7μm insulated carbonyl ferrous powder were prepared and measured the magnetic relative permeability. Such material was investigated to pot the whole power module as a one-step molding, instead of separate molding for the power inductor and the power module. After that, thermal analysis and inductance were calculated and compared.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material

Non-intrusive Reliability Analysis of Multi-layered Slopes in Spatially Variable Soils

Stochastic finite element method and random finite element method can provide rigorous tools for slope reliability analysis incorporating spatial variability of soil properties. However, both of them are difficult to be applied into practice due to the modification of finite-element codes and the low efficiency, respectively. To address these problems, this paper develops a more practical approach called non-intrusive stochastic finite element method (NISFEM) for slope reliability analysis in spatially variable soils. In the NISFEM, the random fields of spatially variable soils are generated using Karhunen-Loeve expansion, and the safety factor of slope stability is calculated using commercial finite-element package. After that, the Hermite polynomial chaos expansion is used to express the safety factor explicitly for slope reliability analysis. In addition, this paper suggests an easy dimension reduction technique to further improve the efficiency of NISFEM, namely, to adopt a relatively small truncated ratio in Karhunen-Loeve expansion. The proposed method is illustrated and verified using a multi-layered soil slope example. Through the sensitivity study, it is found that the vertical spatial variability affects the slope failure probability and the sensitivity of uncertain soil properties significantly

台灣光復初期的民意代表( 一九四六∼一九五一)

[[abstract]]二次大戰後，台灣面臨新的社會轉型及政治變化。光復後的一、二年內，台灣產生大 批的民意代表，包括各縣市參議員、省參議員、國民參政員、制憲國大代表、行憲第 一屆國大代表及立監委。者批社會領導人物，具備什麼成份和素質？他們與過渡中的 術會政治雸環境，產生怎樣的互動關係？這是本論文所要研究的目的所在。 本論文概分三大部分：第一部分敘述光復初期各級民意代表的產生。這一部分除了追 述歷史背景、交待各級民意代表產生的經過之外，並且查究選舉中的紛爭、分析民意 代表的流動情形及其原因。從這部分，可以發現光復初期台灣知識份子參與政治的 渴望，也顯示當時台灣的社會和政治正處在一個過渡而動璗的時段。 第二部分係民意代表的成份分析，這是靜態的分析，其中包括對性別、年齡、教育背 景、社會經歷及戰前政治角色的分析。透過這些分析，不僅顯現三級民意代表之間彼 此不同的特色，同時也顯現地緣因素造成的差異。 第三部分在探討民意代表與光復初期政局的關係。以（１）台灣的光復（２）一九四 七年的社會動亂（３）一九四九年中實施的三七五減租政策及同年的 國府播遷來台 等四大事項做為討論的指標，探討民意代表與時局的關係，從中發現民意代表們在時 局中的一連串迎拒調適的反應。