Browsing by Issue Date, starting with "2016-10-14"

Now showing 1 - 20 of 16346

Probing the intrinsic optical Bloch-mode emission from a 3D photonic crystal
(2016-10-14)
Hsieh, Mei-Li
;
Bur, James A.
;
Du, Qingguo
;
John, Sajeev
;
Lin, Shawn-Yu
We report experimental observation of intrinsic Bloch-mode emission from a 3D tungsten photonic crystal at low thermal excitation. After the successful removal of conventional metallic emission (normal emission), it is possible to make an accurate comparison of the Bloch-mode and the normal emission. For all biases, we found that the emission intensity of the Bloch-mode is higher than that of the normal emission. The Bloch-mode emission also exhibits a slower dependence on (h(omega)/k(b)T) than that of the normal emission. The observed higher emission intensity and a different T-dependence is attributed to Bloch-mode assisted emission where emitters have been located into a medium having local density of states different than the isotropic case. Furthermore, our finite-difference time-domain (FDTD) simulation shows the presence of localized spots at metal-air boundaries and corners, having intense electric field. The enhanced plasmonic field and local non-equilibrium could induce a strong thermally stimulated emission and may be the cause of our unusual observation.
Family of graphene-assisted resonant surface optical excitations for terahertz devices
(2016-10-14)
Lin, I-Tan
;
Liu, Jia-Ming
;
Tsai, Hsin-Cheng
;
Wu, Kaung-Hsiung
;
Syu, Jheng-Yuan
The majority of the proposed graphene-based THz devices consist of a metamaterial that can optically interact with graphene. This coupled graphene-metamaterial system gives rise to a family of resonant modes such as the surface plasmon polariton (SPP) modes of graphene, the geometrically induced SPPs, also known as the spoof SPP modes, and the Fabry-Perot (FP) modes. In the literature, these modes are usually considered separately as if each could only exist in one structure. By contrast, in this paper, we show that even in a simple metamaterial structure such as a one-dimensional (1D) metallic slit grating, these modes all exist and can potentially interact with each other. A graphene SPP-based THz device is also fabricated and measured. Despite the high scattering rate, the effective SPP resonances can still be observed and show a consistent trend between the effective frequency and the grating period, as predicted by the theory. We also find that the excitation of the graphene SPP mode is most efficient in the terahertz spectral region due to the Drude conductivity of graphene in this spectral region.
Metallic nanowires and mesoscopic networks on a free surface of superfluid helium and charge-shuttling across the liquid-gas interface
(2016-10-14)
Moroshkin, P.
;
Batulin, R.
;
Leiderer, P.
;
Kono, K.
;
物理研究所
We investigate the motion of electrically charged metallic nano- and microparticles produced by laser ablation in He gas and injected into superfluid helium. In the presence of a vertical static electric field, the particles either perform a repetitive shuttle-like motion transporting the charge across the liquid-gas interface or become trapped under the free surface of liquid He and coalesce into long filaments and complex two-dimensional mesoscopic networks. A classical electrohydrodynamic model is used to describe the motion of charged microparticles in superfluid He. The resulting filaments and networks are analyzed using electron microscopy. It is demonstrated that each filament is in fact composed of a large number of nanowires with a characteristic diameter of order of 10 nm and extremely large aspect ratios.
Induction of unidirectional pi-electron rotations in low-symmetry aromatic ring molecules using two linearly polarized stationary lasers
(2016-10-14)
Mineo, Hirobumi
;
Yamaki, Masahiro
;
Kim, Gap-Sue
;
Teranishi, Yoshiaki
;
Lin, Sheng Hsien
A new laser-control scenario of unidirectional p-electron rotations in a low-symmetry aromatic ring molecule having no degenerate excited states is proposed. This scenario is based on dynamic Stark shifts of two relevant excited states using two linearly polarized stationary lasers. Each laser is set to selectively interact with one of the two electronic states, the lower and higher excited states are shifted up and down with the same rate, respectively, and the two excited states become degenerate at their midpoint. One of the four control parameters of the two lasers, i.e. two frequencies and two intensities, determines the values of all the other parameters. The direction of p-electron rotations, clockwise or counter-clockwise rotation, depends on the sign of the relative phase of the two lasers at the initial time. An analytical expression for the time-dependent expectation value of the rotational angular momentum operator is derived using the rotating wave approximation (RWA). The control scenario depends on the initial condition of the electronic states. The control scenario with the ground state as the initial condition was applied to toluene molecules. The derived time-dependent angular momentum consists of a train of unidirectional angular momentum pulses. The validity of the RWA was checked by numerically solving the time-dependent Schrodinger equation. The simulation results suggest an experimental realization of the induction of unidirectional p-electron rotations in low-symmetry aromatic ring molecules without using any intricate quantum-optimal control procedure. This may open up an effective generation method of ring currents and current-induced magnetic fields in biomolecules such as amino acids having aromatic ring molecules for searching their interactions.
數學需要電腦與新數學基礎
(國立交通大學丘成桐中心, 2016-10-15)
作者:渥伊沃茨基（Vladimir Voevodsky）
;
譯者:周樹靜　
用電腦輔證數學證明才能避免犯錯
數理簡訊科學真理與民生問題的兩難
(國立交通大學丘成桐中心, 2016-10-15)
編輯室
學界大老論辯中國巨型對撞機的未來
數理簡訊微軟想以10 年之功「解決」癌症
(國立交通大學丘成桐中心, 2016-10-15)
編輯室
科學與科技在 21 世紀得到飛躍性的發展，許多科技成就猶如奇蹟，例如電腦程式 AlphaGo 可以漂亮擊敗圍棋高手李世乭，Tesla 電動跑車的性能和續航力毫不遜於汽油跑車。這賦予大眾一種現代科技無所不能的印象，好像沒有什麼是科技辦不到的。
人工智慧專家系統之父
(國立交通大學丘成桐中心, 2016-10-15)
訪問者:克努斯（Donald Knuth）
;
尼爾森（Nils Nilsson）
;
舒泰克（Len Shustek）
;
譯者:林真
專訪涂林獎得主費根堡之生涯回顧
Growth factors-loaded calcium phosphate/polymer hybrid coating with sequential release behavior prepared via electrochemical deposition method
(2016-10-15)
Sar, Jenny I-Chun
;
Lin, Yen-Zhu
;
Lin, Chung-Kwei
;
Liu, Tse-Ying
;
Chen, San-Yuan
In this study, the dicalcium phosphate dehydrate (DCPD)/carboxymethyl hexanoyl chitosan (CHC) hybrid coating layer with sequential release of BMP-2 and TGF-beta 1 was deposited onto Ti6Al4V substrate by electrochemical co-precipitation method. Different concentrations of amphiphatic chitosan derivative (carboxymethyl hexanoyl chitosan, CHC), BMP-2 and TGF-beta 1-loaded PLA microspheres (PLA/TGF-beta 1 MSs) were co-precipitated with the precursor of DCPD. The resulting DCPD/CHC hybrid coating incorporated with BMP-2 and PLA/TGF-beta 1 MSs was designed for improving the osteoconductive and osteoinductive functionalities of Ti6Al4V. FTIR spectroscopy and X-ray diffraction were used to characterize these hybrid coatings. The drug release profile, MC3T3-E1 cell proliferation and alkaline phosphatase activity were used to investigate the functionality of these hybrid coatings. It was found that the incorporation of CHC could be used as a mean to manipulate the release behavior of growth factor from the DCPD/CHC hybrid coating. In addition, the BMP-2- and PLA/TGF-beta 1 MSs-incorporated DCPD/CHC hybrid coating exhibited a sequential release of BMP-2 and TGF-beta 1 during the first and second two weeks, respectively. Importantly, the DCPD/CHC hybrid coating immersed in simulated body fluid gradually transformed to hydroxyapatite phase. Hence, the BMP-2 and PLA/TGF-beta 1 MSs-incorporated DCPD/CHC hybrid coating exhibited the best cell viability and the highest ALP activity after 14 days. The biocompatible hybrid coating with sequential release functionality proposed in the present study can enhance the osseointegration process and possess promising potential for clinical applications in bone implants and tissue engineering. (C) 2016 Elsevier B.V. All rights reserved.
數理人文第十期中英文對照
(國立交通大學丘成桐中心, 2016-10-15)
編輯室
中英名詞對照
專題-人工智慧與AlphaGo 關於深度學習網絡的兩個問題
(國立交通大學丘成桐中心, 2016-10-15)
郭宗杰
;
趙學信　
為什麼需要深度網絡與非線性機制
我們還需要康德的先驗概念嗎？
(國立交通大學丘成桐中心, 2016-10-15)
張復
從心理學和神經科學重新檢視康德的時空概念
輸給AlphaGo之後
(國立交通大學丘成桐中心, 2016-10-15)
楊芬瑩
人機對奕的價值再探索
數理簡訊望月流的春天
(國立交通大學丘成桐中心, 2016-10-15)
編輯室
ABC 猜想的新進展
編輯曲線人工智慧的新世紀？
(國立交通大學丘成桐中心, 2016-10-15)
編輯室
今年 3 月，AlphaGo 擊敗韓國九段棋手李世乭，震驚了科技界與社會。「人工智慧」、「深度學習」頓時流行起來。想想我們生活中早已充滿各種智慧裝置，突然之間，科幻小說或電影中的情節，似乎指日可待。
AlphaGo 這麼了不起嗎？
(國立交通大學丘成桐中心, 2016-10-15)
作者:尼爾森（Michael Nielsen）
;
譯者:林奕君
捕捉人類直覺的圍棋程式可望帶來深遠影響
Growth factors-loaded calcium phosphate/polymer hybrid coating with sequential release behavior prepared via electrochemical deposition method
(2016-10-15)
Sar, Jenny I-Chun
;
Lin, Yen-Zhu
;
Lin, Chung-Kwei
;
Liu, Tse-Ying
;
Chen, San-Yuan
In this study, the dicalcium phosphate dehydrate (DCPD)/carboxymethyl hexanoyl chitosan (CHC) hybrid coating layer with sequential release of BMP-2 and TGF-beta 1 was deposited onto Ti6Al4V substrate by electrochemical co-precipitation method. Different concentrations of amphiphatic chitosan derivative (carboxymethyl hexanoyl chitosan, CHC), BMP-2 and TGF-beta 1-loaded PLA microspheres (PLA/TGF-beta 1 MSs) were co-precipitated with the precursor of DCPD. The resulting DCPD/CHC hybrid coating incorporated with BMP-2 and PLA/TGF-beta 1 MSs was designed for improving the osteoconductive and osteoinductive functionalities of Ti6Al4V. FTIR spectroscopy and X-ray diffraction were used to characterize these hybrid coatings. The drug release profile, MC3T3-E1 cell proliferation and alkaline phosphatase activity were used to investigate the functionality of these hybrid coatings. It was found that the incorporation of CHC could be used as a mean to manipulate the release behavior of growth factor from the DCPD/CHC hybrid coating. In addition, the BMP-2- and PLA/TGF-beta 1 MSs-incorporated DCPD/CHC hybrid coating exhibited a sequential release of BMP-2 and TGF-beta 1 during the first and second two weeks, respectively. Importantly, the DCPD/CHC hybrid coating immersed in simulated body fluid gradually transformed to hydroxyapatite phase. Hence, the BMP-2 and PLA/TGF-beta 1 MSs-incorporated DCPD/CHC hybrid coating exhibited the best cell viability and the highest ALP activity after 14 days. The biocompatible hybrid coating with sequential release functionality proposed in the present study can enhance the osseointegration process and possess promising potential for clinical applications in bone implants and tissue engineering. (C) 2016 Elsevier B.V. All rights reserved.
專題-人工智慧與AlphaGo 電腦圍棋四十年
(國立交通大學丘成桐中心, 2016-10-15)
顏士淨
;
嚴礽麒
;
許舜欽　
自從電腦圍棋程式 AlphaGo 挑戰世界圍棋冠軍李世乭九段的消息發佈後，電腦圍棋的發展再次受到世人矚目。人機大戰對局立刻成為新聞話題，賽前雖然有各式各樣的預測，但絕大多數看好李世乭，甚至很多人猜測李應該會以 5：0 輕鬆取勝。原因之一是設計電腦圍棋程式的難度非常高，雖在過去歷經幾十年的研究探索，圍棋程式感覺上與人類專家之間仍有極大的差距。
專題-人工智慧與AlphaGo 打開AlphaGo！
(國立交通大學丘成桐中心, 2016-10-15)
顏士淨
電腦圍棋為何能擊敗人類九段棋手
數理簡訊第七屆世界華人數學家大會
(國立交通大學丘成桐中心, 2016-10-15)
編輯室
三年一度的世界華人數學家大會（ICCM），第七屆大會今年 8 月 6 日至 11 日在北京舉行。8 月 6 日，在北京人民大會堂舉行的開幕典禮中，已頒發諸多重要獎項，包括晨興數學獎、陳省身獎、國際合作獎，同一天，也頒發獎勵年輕學子的新世界數學獎。