Browsing by Issue Date, starting with "2018-01-12"

Now showing 1 - 20 of 11464

Carbon-doped SnS2 nanostructure as a high-efficiency solar fuel catalyst under visible light
(2018-01-12)
Shown, Indrajit
;
Samireddi, Satyanarayana
;
Chang, Yu-Chung
;
Putikam, Raghunath
;
Chang, Po-Han
Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an L-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS2 (SnS2-C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS2 lattice, resulting in different photophysical properties as compared with undoped SnS2. This SnS2-C photocatalyst significantly enhances the CO2 reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS2-C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO2 reduction under visible light, where the in situ carbon-doped SnS2 nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.
Microscopic evidence for the dissociation of water molecules on cleaved GaN(1(1)over bar00)
(2018-01-14)
Wu, Shih-Yu
;
Lang, Liang-Wei
;
Cai, Pei-Yang
;
Chen, Yun-Wen
;
Lai, Yu-Ling
The dissociation of water molecules absorbed on a cleaved non-polar GaN(1(1)over bar00) surface was studied primarily with synchrotron-based photoemission spectra and density-functional-theory calculations. The adsorbed water molecules are spontaneously dissociated into hydrogen atoms and hydroxyl groups at either 300 or 130 K, which implies a negligible activation energy (<11 meV) for the dissociation. The produced H and OH were bound to the surface nitrogen and gallium on GaN(1(1)over bar00) respectively. These results highlight the promising applications of the non-polar GaN(1(1)over bar00) surface in water dissociation and hydrogen generation.
可預測的都很無趣，我們應該尋找驚奇
(國立交通大學丘成桐中心, 2018-01-15)
格夏普拉達
;
翁秉仁　
;
Oscar Garc a-Prada
1966 年費爾茲獎與2004 年阿貝爾獎得主阿提雅訪談
Granger causal connectivity dissociates navigation networks that subserve allocentric and egocentric path integration
(2018-01-15)
Lin, Chin-Teng
;
Chiu, Te-Cheng
;
Wang, Yu-Kai
;
Chuang, Chun-Hsiang
;
Gramann, Klaus
Studies on spatial navigation demonstrate a significant role of the retrosplenial complex (RSC) in the transformation of egocentric and allocentric information into complementary spatial reference frames (SRFs). The tight anatomical connections of the RSC with a wide range of other cortical regions processing spatial information support its vital role within the human navigation network. To better understand how different areas of the navigational network interact, we investigated the dynamic causal interactions of brain regions involved in solving a virtual navigation task. EEG signals were decomposed by independent component analysis (ICA) and subsequently examined for information flow between clusters of independent components (ICs) using direct short-time directed transfer function (sdDTF). The results revealed information flow between the anterior cingulate cortex and the left prefrontal cortex in the theta (4-7 Hz) frequency band and between the prefrontal, motor, parietal, and occipital cortices as well as the RSC in the alpha (8-13 Hz) frequency band. When participants prefered to use distinct reference frames (egocentric vs. allocentric) during navigation was considered, a dominant occipito-parieto-RSC network was identified in allocentric navigators. These results are in line with the assumption that the RSC, parietal, and occipital cortices are involved in transforming egocentric visual-spatial information into an allocentric reference frame. Moreover, the RSC demonstrated the strongest causal flow during changes in orientation, suggesting that this structure directly provides information on heading changes in humans. (C) 2017 Elsevier B.V. All rights reserved.
Using pre-distorted PAM-4 signal and parallel resistance circuit to enhance the passive solar cell based visible light communication
(2018-01-15)
Wang, Hao-Yu
;
Wu, Jhao-Ting
;
Chow, Chi-Wai
;
Liu, Yang
;
Yeh, Chien-Hung
Using solar cell (or photovoltaic cell) for visible light communication (VLC) is attractive. Apart from acting as a VLC receiver (Rx), the solar cell can provide energy harvesting. This can be used in self-powered smart devices, particularly in the emerging "Internet of Things (IoT)'' networks. Here, we propose and demonstrate for the first time using pre-distortion pulse-amplitude-modulation (PAM)-4 signal and parallel resistance circuit to enhance the transmission performance of solar cell Rx based VLC. Pre-distortion is a simple non-adaptive equalization technique that can significantly mitigate the slow charging and discharging of the solar cell. The equivalent circuit model of the solar cell and the operation of using parallel resistance to increase the bandwidth of the solar cell are discussed. By using the proposed schemes, the experimental results show that the data rate of the solar cell Rx based VLC can increase from 20 kbit/s to 1.25 Mbit/s (about 60 times) with the bit error-rate (BER) satisfying the 7% forward error correction (FEC) limit. (C) 2017 Elsevier B.V. All rights reserved.
畫貴思其一
(國立交通大學丘成桐中心, 2018-01-15)
劉巨德
闡述其落筆之前，「需精思其『蒙』，精思其『一』」的畫思，並提供作者近期個展的代表作品以為印證。
A level-set method for two-phase flows with soluble surfactant
(2018-01-15)
Xu, Jian-Jun
;
Shi, Weidong
;
Lai, Ming-Chih
;
應用數學系
;
Department of Applied Mathematics
A level-set method is presented for solving two-phase flows with soluble surfactant. The Navier-Stokes equations are solved along with the bulk surfactant and the interfacial surfactant equations. In particular, the convection-diffusion equation for the bulk surfactant on the irregular moving domain is solved by using a level-set based diffusive-domain method. A conservation law for the total surfactant mass is derived, and a re-scaling procedure for the surfactant concentrations is proposed to compensate for the surfactant mass loss due to numerical diffusion. The whole numerical algorithm is easy for implementation. Several numerical simulations in 2D and 3D show the effects of surfactant solubility on drop dynamics under shear flow. (C) 2017 Elsevier Inc. All rights reserved.
先秦兩漢的歷史敘事
(國立交通大學丘成桐中心, 2018-01-15)
李隆獻
從「敘事」觀點切入，重新閱讀先秦兩漢的歷史文本，並運用西方敘事理論與出土考古文獻，豐富整個論述的完整性。
中美科技競賽，誰會贏？
(國立交通大學丘成桐中心, 2018-01-15)
劉裘蒂
丘成桐談中國基礎科學現狀
數理人文第十三期中英文對照
(國立交通大學丘成桐中心, 2018-01-15)
編輯室
中英名詞對照
做數學最美妙的是大量的合作與分享
(國立交通大學丘成桐中心, 2018-01-15)
傑克森
;
周樹靜
;
Allyn Jackson
2000 年沃爾夫獎得主博特訪談
編輯曲線數學與人類的福祉
(國立交通大學丘成桐中心, 2018-01-15)
編輯室
介紹本期內容
Charged BTZ-like black hole solutions and the diffusivity-butterfly velocity relation
(2018-01-15)
Ge, Xian-Hui
;
Sin, Sang-Jin
;
Tian, Yu
;
Wu, Shao-Feng
;
Wu, Shang-Yu
We show that there exists a class of charged BTZ-like black hole solutions in Lifshitz spacetime with a hyperscaling violating factor. The charged BTZ black hole is characterized by a charge-dependent logarithmic term in the metric function. As concrete examples, we give five such charged BTZ-like black hole solutions and the standard charged BTZ metric can be regarded as a special instance of them. In order to check the recent proposed universal relations between diffusivity and the butterfly velocity, we first compute the diffusion constants of the standard charged BTZ black holes and then extend our calculation to arbitrary dimension d, exponents z and theta. Remarkably, the case d = theta and z = 2 is a very special in that the charge diffusion D-c is a constant and the energy diffusion D-e might be ill-defined, but v(B)(2)tau diverges. We also compute the di ff usion constants for the case that the DC conductivity is fi nite but in the absence of momentum relaxation.
數理簡訊拓樸物理學自閉症與數學天才 2018 年突破數學獎
(國立交通大學丘成桐中心, 2018-01-15)
編輯室
純數學與物理的再連結
讓鮮魚呈現自己的美味
(國立交通大學丘成桐中心, 2018-01-15)
謝復興
;
吳宏達
漫談數據、科學、計算
數學與你的幸福
(國立交通大學丘成桐中心, 2018-01-15)
蘇宇瑞
;
Francis Edward Su
本文改寫自蘇宇瑞（Francis Edward Su）2017 年在AMS 與 MAA 的聯合數學大會上，為美國數學協會主席任期屆滿所做的卸任演說。
Neutralized chimeric DNA probe for detection of single nucleotide polymorphism on surface plasmon resonance biosensor
(2018-01-15)
Huang, Chun-Jen
;
Lin, Zhong-En
;
Yang, Yuh-Shyong
;
Chan, Hardy Wai-Hong
;
Chen, Wen-Yih
An implementation of neutralized chimeric DNA oligomer as a probe for sensitive detection of single nucleotide polymorphisms (SNPs) on a surface plasmon resonance imaging sensor is investigated. The chimeric DNA oligomer was synthesized in a conventional DNA synthesizer, containing neutral nucleotides with a methylated phosphate group. The secondary structures and melting points of the chimeric DNA fragment and its complexes with perfect-matched and single-mismatched complementary DNA molecules were examined by using circular dichroism and UV vis spectroscopy in comparison with the native probe DNA counterpart. The results indicate that the chimeric DNA complexes can form a B-form structure and exhibit high thermostability. Moreover, the hybridization and discrimination efficiency of the chimeric probe DNA for the SNP genotyping were verified by using the SPRi sensor under different experimental conditions. The data reveal the effects of the ionic strength and operation temperature on the selectivity of the chimeric probe DNA for the SNP detection. The hybridization condition with a low ionic strength and high temperature allows the chimeric probe DNA distinguishing perfect-matched and single-mismatched target DNA molecules to the best extent, likely due to the reduced electrostatic repulsive force and presence of the additional methyl group on the backbone. Consequently, the direct and label-free detection with the SPR technique and neutralized chimeric probe DNA can be realized for the SNP genotyping by optimizing the operation condition and sequence design.
中國基礎科學發展
(國立交通大學丘成桐中心, 2018-01-15)
丘成桐
丘成桐對中國科學教育者的錚錚之言。他比較東西方思想發展，說明為何古希臘思想為基礎科學的發展奠定了基礎，並強調基礎科學和哲學的內在關聯。
學習的奧祕是遺忘
(國立交通大學丘成桐中心, 2018-01-15)
渥秋華
;
紀露結
;
Natalie Wolchover
揭開深度學習神秘黑箱的新理論
A remark on an integral characterization of the dual of BV
(2018-01-15)
Fusco, Nicola
;
Spector, Daniel
;
應用數學系
;
Department of Applied Mathematics
In this paper, we show how under the continuum hypothesis one can obtain an integral representation for elements of the topological dual of the space of functions of bounded variation in terms of Lebesgue and Kolmogorov-Burkill integrals. (C) 2017 Elsevier Inc. All rights reserved.