Browsing by Issue Date, starting with "2016-07-15"

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Vesicle electrohydrodynamic simulations by coupling immersed boundary and immersed interface method
(2016-07-15)
Hu, Wei-Fan
;
Lai, Ming-Chih
;
Seol, Yunchang
;
Young, Yuan-Nan
;
應用數學系
In this paper, we develop a coupled immersed boundary (IB) and immersed interface method (IIM) to simulate the electrodeformation and electrohydrodynamics of a vesicle in Navier-Stokes leaky dielectric fluids under a DC electric field. The vesicle membrane is modeled as an inextensible elastic interface with an electric capacitance and an electric conductance. Within the leaky dielectric framework and the piecewise constant electric properties in each fluid, the electric stress can be treated as an interfacial force so that both the membrane electric and mechanical forces can be formulated in a unified immersed boundary method. The electric potential and transmembrane potential are solved simultaneously via an efficient immersed interface method. The fluid variables in Navier-Stokes equations are solved using a projection method on a staggered MAC grid while the electric potential is solved at the cell center. A series of numerical tests have been carefully conducted to illustrate the accuracy and applicability of the present method to simulate vesicle electrohydrodynamics. In particular, we investigate the prolateoblate-prolate (POP) transition and the effect of electric field and shear flow on vesicle electrohydrodynamics. Our numerical results are in good agreement with those obtained in previous work using different numerical algorithms. (C) 2016 Elsevier Inc. All rights reserved.
學術界揭竿而起—楊芬瑩
(國立交通大學丘成桐中心, 2016-07-15)
楊芬瑩
推倒貪婪期刊付費高牆！
數理簡訊 PK 大戰與對局論
(國立交通大學丘成桐中心, 2016-07-15)
編輯室
零和賽局混合策略的精彩實例
M2M Encountering: Collaborative Localization via Instant Inter-Particle Filter Data Fusion
(2016-07-15)
Qiu, Jun-Wei
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
Much research has addressed indoor localization by integrating portable/wearable sensing and communication technologies. While GPS has dominated the outdoor environments, indoor localization schemes have to consider different observations, such as radio-frequency signals, vision or motions data, and apply data fusion to combine various sensor inputs. In this paper, we observe that when two devices meet up, which we call machine-to-machine (M2M) encountering, they can collaboratively calibrate each other\'s potential locations via M2M communications. We apply this technique to particle filter (PF), a common fusion technique, and show how to take the M2M encountering opportunities, which may happen frequently in crowded areas, to allow user devices to collaboratively calibrate their locations. Hence, the PF technique, which normally fuses observations from individual devices, is extended to an inter-PF, cross-device domain. We validate our inter-PF solution by simulations as well as a prototype system with smartphones and ZigBee infrastructure deployed in an office building. It is verified that the inter-PF helps converge the positioning results more rapidly, and improves location quality. Also, the proposed encountering mechanism has potential to be applied to other localization algorithms to improve their accuracy.
Targeted inactivation of murine Ddx3x: essential roles of Ddx3x in placentation and embryogenesis
(2016-07-15)
Chen, Chia-Yu
;
Chan, Chieh-Hsiang
;
Chen, Chun-Ming
;
Tsai, Yin-Shuan
;
Tsai, Tsung-Yuan
The X-linked DEAD-box RNA helicase DDX3 (DDX3X) is a multifunctional protein that has been implicated in gene regulation, cell cycle control, apoptosis, and tumorigenesis. However, the precise physiological function of Ddx3x during development remains unknown. Here, we show that loss of Ddx3x results in an early post-implantation lethality in male mice. The size of the epiblast marked by Oct3/4 is dramatically reduced in embryonic day 6.5 (E6.5) Ddx3x(-)/Y embryos. Preferential paternal X chromosome inactivation (XCI) in extraembryonic tissues of Ddx3x heterozygous (Ddx3x(-/+)) female mice with a maternally inherited null allele leads to placental abnormalities and embryonic lethality during development. In the embryonic tissues, Ddx3x exhibits developmental-and tissue-specific differences in escape from XCI. Targeted Ddx3x ablation in the epiblast leads to widespread apoptosis and abnormal growth, which causes embryonic lethality in the Sox2-cre/+; Ddx3x(flox)/Y mutant around E11.5. The observation of significant increases in gamma H2AX and p-p53(Ser15) indicates DNA damage, which suggests that loss of Ddx3x leads to higher levels of genome damage. Significant upregulation of p21(WAF1/Cip1) and p15(Ink4b) results in cell cycle arrest and apoptosis in Ddx3x-deficient cells. These results have uncovered that mouse Ddx3x is essential for both embryo and extraembryonic development.
L-p gradient estimate for elliptic equations with high-contrast conductivities in R-n
(2016-07-15)
Yeh, Li-Ming
;
應用數學系
;
Department of Applied Mathematics
Uniform estimate for the solutions of elliptic equations with high-contrast conductivities R-n is concerned. The space domain consists of a periodic connected sub-region and a periodic disconnected matrix block subset. The elliptic equations have fast diffusion in the connected sub-region and slow diffusion in the disconnected subset. Suppose epsilon is an element of (0, 1] is the diameter of each matrix block and omega(2) is an element of a (0, 1] is the conductivity ratio of the disconnected matrix block subset to the connected sub-region. It is proved that the W-1,W-p norm of the elliptic solutions in the connected sub-region is bounded uniformly in epsilon, is an element of, on when epsilon <= is an element of, the L-p norm of the elliptic solutions in the whole space is bounded uniformly in epsilon, omega; the W-1,W-p norm of the elliptic solutions in perforated domains is bounded uniformly in epsilon. However, the L-p norm of the second order derivatives of the solutions in the connected sub-region may not be bounded uniformly in epsilon, omega. (C) 2016 Elsevier Inc. All rights reserved.
數理簡訊格羅騰迪克的晚年手稿
(國立交通大學丘成桐中心, 2016-07-15)
編輯室
無恆產者的遺產之爭
數理簡訊英國三年拍了四部數學電影
(國立交通大學丘成桐中心, 2016-07-15)
編輯室
拉曼努真的故事《天才無限家》正上演
Targeted inactivation of murine Ddx3x: essential roles of Ddx3x in placentation and embryogenesis
(2016-07-15)
Chen, Chia-Yu
;
Chan, Chieh-Hsiang
;
Chen, Chun-Ming
;
Tsai, Yin-Shuan
;
Tsai, Tsung-Yuan
The X-linked DEAD-box RNA helicase DDX3 (DDX3X) is a multifunctional protein that has been implicated in gene regulation, cell cycle control, apoptosis, and tumorigenesis. However, the precise physiological function of Ddx3x during development remains unknown. Here, we show that loss of Ddx3x results in an early post-implantation lethality in male mice. The size of the epiblast marked by Oct3/4 is dramatically reduced in embryonic day 6.5 (E6.5) Ddx3x(-)/Y embryos. Preferential paternal X chromosome inactivation (XCI) in extraembryonic tissues of Ddx3x heterozygous (Ddx3x(-/+)) female mice with a maternally inherited null allele leads to placental abnormalities and embryonic lethality during development. In the embryonic tissues, Ddx3x exhibits developmental-and tissue-specific differences in escape from XCI. Targeted Ddx3x ablation in the epiblast leads to widespread apoptosis and abnormal growth, which causes embryonic lethality in the Sox2-cre/+; Ddx3x(flox)/Y mutant around E11.5. The observation of significant increases in gamma H2AX and p-p53(Ser15) indicates DNA damage, which suggests that loss of Ddx3x leads to higher levels of genome damage. Significant upregulation of p21(WAF1/Cip1) and p15(Ink4b) results in cell cycle arrest and apoptosis in Ddx3x-deficient cells. These results have uncovered that mouse Ddx3x is essential for both embryo and extraembryonic development.
探索小數點以下十兆位的秘密
(國立交通大學丘成桐中心, 2016-07-15)
作者:貝利（David H. Bailey）
;
波宛（Jonathan M. Borwein）
;
麥廷理（Andrew Mattingly）
;
外特威克（Glenn Wightwick）
;
譯者:林真
從 π 的 BBP 公式浪潮談起
雷公的髮髻—王寶貫
(國立交通大學丘成桐中心, 2016-07-15)
王寶貫
從人造衛星鳥瞰風暴之頂
Product of two positive contractions
(2016-07-15)
Li, Chi-Kwong
;
Pelejo, Diane Christine
;
Wang, Kuo-Zhong
;
應用數學系
;
Department of Applied Mathematics
Several characterizations are given for a square matrix that can be written as the product of two positive (semidefinite) contractions. Based on one of these characterizations, and the theory of alternating projections, a Matlab program is written to check the condition and construct the two positive contractions whose product equal to the given matrix, if they exist. (C) 2016 Elsevier Inc. All rights reserved.
為何知識論始終未能獲得中國哲學的青睞
(國立交通大學丘成桐中心, 2016-07-15)
林鎮國
以哲學史上三場爭辯為例
猶存俠骨齊夷意（上）
(國立交通大學丘成桐中心, 2016-07-15)
聯合編輯:亞丁（Michael Artin）
;
傑克森（Allyn Jackson）
;
曼弗德（David Mumford）
;
泰特（John Tate）
;
譯者:翁秉仁
悼亞歷山大．格羅騰迪克（1928-2014）
Thermoelectric properties of nanocrystalline Bi3Se2Te thin films grown using pulsed laser deposition
(2016-07-15)
Tuyen, Le Thi Cam
;
Phuoc Huu Le
;
Luo, Chih Wei
;
Leu, Jihperng
;
材料科學與工程學系
This study reports the material and thermoelectric properties of n-type nanocrystalline Bi-Se-Te thin films grown using pulse laser deposition (PLD) with a Bi2Se2Te single crystal as the target. In order to optimize the transport and thermoelectric properties, Bi-Se-Te thin films are fabricated by maintaining the substrate temperature (T-S) between 200 and 350 degrees C and a helium gas pressure (P-He) from 0.027 to 86.7 Pa. Unlike the target, all deposited films unexpectedly exhibit Bi2Se2Te phase with highly c-axis orientation, because of the high re-evaporation rates of Se and Te at the elevated T-S >= 200 degrees C. The estimated grain (crystalline) size ranges between 18.4 and 39.4 nm, and this monotonically increases as TS increases. The Bi3Se2Te films demonstrate excellent electrical conductivities owning to the high carrier concentration in the order of 10(20) cm(-3). A window of deposition conditions for high thermoelectric power factors (PF) is T-S of 250-350 degrees C and P-He of 40 Pa. The optimal PF is 8.3 mu W/cmK(2) for the Bi3Se2Te film prepared at 250 degrees C and 40 Pa. (C) 2016 Elsevier B.V. All rights reserved.
Extremality of numerical radii of matrix products
(2016-07-15)
Gau, Hwa-Long
;
Wu, Pei Yuan
;
應用數學系
;
Department of Applied Mathematics
For two n-by-n matrices A and B, it was known before that their numerical radii satisfy the inequality w(AB) <= 4w(A)w(B), and the equality is attained by the 2-by-2 matrices A = [GRAPHICS] and B = [GRAPHICS] . Moreover, the constant "4" here can be reduced to "2" if A and B commute, and the corresponding equality is attained by A = I-2 circle times [GRAPHICS] and B = [GRAPHICS] circle times I-2. In this paper, we give a complete characterization of A and B for which the equality holds in each case. More precisely, it is shown that w(AB) = 4w(A)w(B) (resp., w(AB) = 2w(A)w(B) for commuting A and B) if and only if either A or B is the zero matrix, or A and B are simultaneously unitarily similar to matrices of the form [GRAPHICS] circle plus A\' and [GRAPHICS] circle plus B\' (resp., [GRAPHICS] circle plus A\' and [GRAPHICS] circle plus B\') with w(A\') <= vertical bar a vertical bar/2 and w(B\') <= vertical bar b vertical bar/2. An analogous characterization for the extremal equality for tensor products is also proven. For doubly commuting matrices, we use their unitary similarity model to obtain the corresponding result. For commuting 2-by-2 matrices A and B, we show that w(AB) = w(A)w(B) if and only if either A or B is a scalar matrix, or A and B are simultaneously unitarily similar to [GRAPHICS] and [GRAPHICS] with vertical bar a(1)vertical bar >= vertical bar a(2)vertical bar and vertical bar b(1)vertical bar >= vertical bar b(2)vertical bar. (C) 2016 Elsevier Inc. All rights reserved.
Lessons from a failure case of an excavated floodway supported by precast cantilever pile walls
(2016-07-15)
Cheng, Meng-Hsiung
;
Huang, Ming-Wan
;
Pan, Yii-Wen
;
Liao, Jyh-Jong
;
土木工程學系
The Gangweigou floodway, across the Quiren and Rende districts in Tainan, Taiwan, was designed to bypass partial discharge in the Gangweigou River during heavy rainfall events for the purpose of flood control. This flood way was an excavated open channel supported by single or double rows of precast RC cantilever pile walls on each side of its banks; these piles were installed by the jetting-assisted method. Twenty days after the completion of the floodway, it was put to work for the first time during a heavy rainfall. Unexpectedly, the cantilever pile walls in several sections failed and caused the collapse of the slope behind the walls. This paper explores the failure mechanism and the real causes of failure in this case. Based on the conditions of hydrology and hydraulics, failure processes and the results of stability analyses, it was concluded that ignoring a possible bed incision or bank erosion was likely the primary problem with the improper design. The most critical condition was when the water level in the floodway quickly dropped, which resulted in rapid drawdown. The failure of the case could have been avoided if both the rapid drawdown condition and the potential of the channel bed incision were considered. (C) 2016 Elsevier B.V. All rights reserved.
戴森傳奇
(國立交通大學丘成桐中心, 2016-07-15)
林開亮
從數論、QED 到科普寫作大師
編輯曲線數學的另一方風景
(國立交通大學丘成桐中心, 2016-07-15)
編輯室
在本刊第 7 期，曼弗德的〈數學之美〉中談到了阿提雅等人的認知科學實驗，由數學家看一系列數學公式，並為它們的優美程度給分（該文有公式列表）。
數理簡訊高等數學能力從何而來
(國立交通大學丘成桐中心, 2016-07-15)
編輯室
數學與語言有相同的演化根源嗎？