Browsing by Author "Wang, Chun-Chieh"

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A counter electrode based on hollow spherical particles of polyaniline for a dye-sensitized solar cell
(2012)
Huang, Kuan-Chieh
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Hu, Chih-Wei
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Tseng, Chen-Ya
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Liu, Chen-Yu
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Yeh, Min-Hsin
Hollow spherical polyaniline (hsPANI) particles are synthesized and deposited on an ITO/glass substrate to prepare a counter electrode (designated as hsPANI-CE) for a dye-sensitized solar cell (DSSC). The structure and crystallization of the hsPANI particles are characterized by using high resolution transmission electron microscopy (HR-TEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectra. A power-conversion efficiency (h) of 6.84% is obtained for the DSSC with the hsPANI-CE, while it is 6.02% in the case of the DSSC with a CE based on pristine PANI (designated as PANI-CE). Such enhancement is attributed to the hsPANI film having a larger active surface area (A) of 0.191 cm(2), compared to that of the PANI film (A = 0.126 cm(2)), both values being estimated by a rotating disk electrode (RDE). Cyclic voltammetric (CV) curves have evidenced that the electro-catalytic ability of the hsPANI-CE for the reduction of tri-iodide (I-3(-)) ions is higher than that of the PANI-CE. As a reference, the DSSC with a Pt-sputtered CE gives an h of 7.17%. Electrochemical impedance spectroscopic (EIS) spectra are used to substantiate the photovoltaic behaviors. The results suggest that the film consisting of hsPANI particles can be a potential catalytic layer for the replacement of Pt in the CE of a DSSC.
A New Method for Calibrating a Six-DOF Joint Force/Torque Sensor
(2014-01-01)
Tran Trong Hieu
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Chao, Paul C-P
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Wang, Yu-Jen
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Wang, Chun-Chieh
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電機工程學系
A SIX-DOF FORCE/TORQUE SENSOR FOR COLLABORATIVE ROBOT AND ITS CALIBRATION METHOD
(2017-01-01)
Trong-Hieu Tran
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Tan-Phat Phan
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Chao, Paul C. -P
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Wang, Yu-Jen
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Wang, Chun-Chieh
This study presents a new six-DOF force/torque sensor and its calibration method for a "collaborative robot or cobot". This new calibration method applies the so-called "maximum likelihood estimation (MLE)". MLE is used to determine and identify the parameters related to applied torques/forces and resulted deformations at varied locations of the sensor structure. Formulating the relations in a vector-matrix form, such parameters are captured as the coefficients in a matrix relating torques/forces to angular/linear deformations in different directions. In addition to applying MLE, finite element (FEM) modeling and analysis are conducted to generate realistic-like empirical data for the aforementioned calibration computation based on MLE. The matrix formed by these coefficients can then predict forces and torques with good accuracy via deformations detected by strain gauges. Seen in simulation results, the worst sum of error for three forces is less than 0.04%, while that for three torques is less than 0.00005%. Very small values of sum of error demonstrate a strong correlation of the model with the results obtained from MLE, indicating high precision in sensing forces and torques without decoupling matrix. The developed sensor is highly suitable for real-time sensing of multidimensional interactive forces/torques in industrial robots.
An IP-decoupling approach to host mobility
(2007-01-01)
Wang, Chun-Chieh
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Chi, Kuang-Hui
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Tseng, Chien-Chao
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資訊工程學系
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Department of Computer Science
This paper presents the design, implementation, and performance evaluation of an approach to supporting host mobility in the wireless Internet. We observe that a single IP address conventionally serves dual purposes: a network-level routing directive and an endpoint identity of a certain session in transport or upper layers. Therefore, when a host affiliates with a new IP address due to movements, any pre-established active session thereupon suffers outage. Unlike prior schemes exploiting mobility agents, we propose to let a host use two IP addresses for network- and transport-layer identifications, respectively, and introduce a translation table that associates the two identities. Such an association results from querying or dynamic updates to the Domain Name System, or from direct message exchanges between two communication peers so as to optimize delivery paths. Simulation results show that our scheme outperforms counterpart Mobile IP and Mobile IPv6, in terms of communication delay, packet error rate, message space overhead, and potential packet loss during handoffs. Additionally, qualitative discussions conclude that our proposal lends itself to IPv4 and IPv6 interconnected networks, or multi-tier environment such as wireless Local Area Networks and mobile telecommunication overlay systems.
An optimal design of thermal-actuated and piezoresistive-sensed CMOS-MEMS resonant sensor
(2013-11-01)
Wang, Chun-Chieh
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Tsai, Chun-Yin
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Chen, Tsung-Lin
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Liao, Sin-Hao
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機械工程學系
This paper proposes an optimal design of the thermal-actuated, piezoresistive-sensed resonator fabricated by a foundry-provided CMOS-MEMS process. The optimal design is achieved both by quantitatively comparing the mechanical properties of different composite films as well as by deriving an analytical model for determining the device dimensions. The analytical model includes a stress model of an asymmetric mechanical structure and a piezoresistivity model of the heavily doped, n-type polysilicon film. The analytical model predicts that the optimal length of the displacement sensor is 200 mu m when the thermal actuator is 200 mu m in length and the absorption plate is 100 mu m in length. Additionally, the model predicts the resistivity of the polysilicon film of (6.8 +/- 2.2) m Omega cm and the gauge factor of (6.8 +/- 2.9) when the grain size is (250 +/- 100) nm. Experimental results agree well with simulation results. Experimental data show that the resonant frequency of the device is 80.06 kHz and shifts to 79.8 kHz when a brick of Pt mass is deposited on the resonator. The mass of the Pt estimated from the frequency shift is 4.5419 x 10(-12) kg, while estimated from the measured dimension is 4.4204 x 10(-12) kg. Sensitivity of the resonant sensor is calculated to be 1.8 x 10(2) Hz ng(-1). Experimental results further show that the polysilicon film used in the experiments has a grain size of (241 +/- 105) nm, an average gauge factor of 5.56 and average resistivity of 5.5 m Omega cm.
Application of Optimum Tire Force Distribution to Vehicle Motion Control
(2012)
Wang, Chun-Chieh
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Cheng, Sheng-Yuan
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Hsiao, Tesheng
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Chou, Wei-Yao
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交大名義發表
This paper presents a motion control scheme for a front-wheel-steering/rear-wheel-driving (FWS/RWD) vehicle using the optimum tire force distribution method. The proposed control system is divided into three layers: the upper controller, the optimum tire force distribution algorithm, and the lower controller. When the driver commands the vehicle, the upper controller computes the total desired longitudinal tire force, lateral tire force, and the desired yaw moment which allow the vehicle to follow the given reference trajectory. Then the desired forces and moments are optimally distributed to the four wheels, and the lower controller compensates for the nonlinear and uncertain characteristics of the tire dynamics to generate the desired forces. Finally, simulations are carried out to verify the effectiveness of the proposed control scheme.
Calcitriol exerts a mineralization-inductive effect comparable to that of vitamin C in cultured human periodontium cells
(2019-01-01)
Hong, Hsiang-Hsi
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Hong, Adrienne
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Wang, Chun-Chieh
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Huang, E-Wen
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Chiang, Cheng-Cheng
This study inspected whether calcitriol could exert a mineralization-inductive effect comparable to that of vitamin C in cultured human periodontium cells (hPDCs). The mRNA expression of the mineralization-related biomarkers core-binding factor subunit alpha-1 (Cbfal), collagen 1 alpha l (Col-l), alkaline phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP), osteocalcin (OCN), vitamin D receptor (VDR), cementum protein 1 (CEMP-1), cementum attachment protein (CAP), interleukin 6 (IL-6), transforming growth factor-beta 1 (TGF-beta 1) and osteoprotegerin (OPG) was surveyed after incubation of hPDCs with vitamin C and calcitriol for 2 weeks. Translational expression information from ALP activity and CEMP-1 and CAP immunofluorescence assays was acquired from hPDCs at the second and third weeks. Extracellular calcifications were confirmed by von Kossa staining, Alizarin Red staining and synchrotron transmission X-ray microscopy (TXM) at the fourth and fifth weeks. It was found that both vitamin C and calcitriol not only increased mineralization-related mRNA fold-changes but also enhanced ALP activity, CEMP1 immunofluorescence, von Kossa and Alizarin Red staining and TXM-associated calcifications. Generally, 10(-8) M calcitriol displayed greater mineralization significance than 10(-7) M calcitriol in the assays tested. However, vitamin C stimulated lower Cbfal, Col-1, ALP, OPN, BSP, OCN, VDR, CEMP-1 and IL-6 mRNA fold-changes than 10(-8) M calcitriol. Finally, TXM analysis indicated that a 10(-8) M calcitriol treatment stimulated greater calcifications than vitamin C treatment. Therefore, the analytical results confirmed the osteo-inductive potential of vitamin C in cultured hPDCs. In contrast, 10(-8) M calcitriol could potentially function as a substitute because it stimulates a greater mineralization effect than vitamin C or 10(-7) M calcitriol.
Corrosion mechanism of annealed equiatomic AlCoCrFeNi tri-phase high-entropy alloy in 0.5 M H2SO4 aerated aqueous solution
(2019-08-15)
Yen, Chao-Chun
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Lu, Hsueh-Ning
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Tsai, Ming-Hung
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Wu, Bo-Wei
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Lo, Yu-Chieh
This work investigates the corrosion mechanism of annealed equiatomic AlCoCrFeNi tri-phase alloy in 0.5 M H2SO4 aerated aqueous solution. Experimental results indicate that the B2 matrix is preferentially corroded away while grain-boundary FCC and labyrinth-like BCC endure, consistent with the tendency of formation energy for monolayer hydroxide on the (001) plane of three phases calculated by the first principle based on density function theory. Furthermore, the stable passive current density is related to lower k(sp) values of Co(OH)(3), Fe (OH)(3), and Cr(OH)(3), while the annealing effect on enhancing corrosion resistance is owing to the more uniformity of passive hydroxide film.
Differences in texture evolution from low-entropy to high-entropy face-centered cubic alloys during tension test
(2020-03-01)
Lin, Kuan-Hao
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Chang, Shou-Yi
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Lo, Yu-Chieh
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Wang, Chun-Chieh
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Lin, Su-Jien
Texture evolution during tension test was investigated on three face-centered cubic (FCC) metals, namely, Ni (unary), equiatomic CrFeNi (ternary), and equiatomic CoCrFeMnNi (quinary) with small and large grain sizes of similar to 20 and similar to 100 mu m, respectively. The microtextures for 18%, 36% and 54% engineering strains of a tension-interrupted specimen were characterized on the same area. The three metals exhibited a similar texture evolution, which the fraction of {001}//ND remains constant However, the fraction of {011}//ND decreases, whereas that of {111}//ND increases. On the other hand, the fraction of <001>//RD also remains constant, that of <011>//RD decreases, and that of <111>//RD increases. However, the several differences still were found during plastic deformation. Fine-grained Ni initiated a significantly crystallographic rotation (CRo) at the lower strain, increased with strain and then remained nearly unchanged as strain was higher than 18%. Coarse-grained Ni delayed this rotation and slowly developed the trend at large strains. As for CrFeNi, the comparison between fine-grained and coarse-grained structure does not have obvious difference. As for fine-grained CoCrFeMnNi, it can be seen that an obvious CRo develops under 36% strain, and maintains constant over 36% strain. But the coarse-grained CoCrFeMnNi reveals that the significant CRo develops continuously from 0% to 54% strain. The mechanisms for the effects of number of element and grain size in the present study are elucidated.
Dinitrosyliron Complex [(PMDTA)Fe(NO)(2)]: Intermediate for Nitric Oxide Monooxygenation Activity in Nonheme Iron Complex
(2020-06-15)
Lu, Shan
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Chiou, Tzung-Wen
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Li, Wei-Liang
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Wang, Chun-Chieh
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Wang, Yun-Ming
Despite a comprehensive study on the biosynthesis and function of nitric oxide, biological metabolism of nitric oxide, especially when its concentration exceeds the cytotoxic level, remains elusive. Oxidation of nitric oxide by O-2 in aqueous solution has been known to yield NO2. On the other hand, a biomimetic study on the metal-mediated conversion of NO to NO2/NO3- via O-2 reactivity disclosed a conceivable pathway for aerobic metabolism of NO. During the NO-to-NO2-/NO3- conversion, transient formation of metal-bound peroxynitrite and subsequent release of (NO2)-N-center dot via O-O bond cleavage were evidenced by nitration of tyrosine residue or 2,4-di-tert-butylphenol (DTBP). However, the synthetic/catalytic/enzymatic cycle for conversion of nitric oxide into a nitrite pool is not reported. In this study, sequential reaction of the ferrous complex [(PMDTA)Fe(kappa(2) -O,O'- NO2)(kappa(1) -O-NO2)] (3; PMDTA = pentamethyldiethylenetriamine) with NO(g), KC8, and O-2 established a synthetic cycle, complex 3 -> {Fe(NO)(2)}(9) DNIC [(PMDTA)Fe(NO)(2)][NO2] (4) -> {Fe(NO)(2)}(10) DNIC [(PMDTA)Fe(NO)(2)] (1) -> [(PMDTA)(NO)- Fe(kappa(2)-O,N-ONOO)] (2) -> complex 3, for the transformation of nitric oxide into nitrite. In contrast to the reported reactivity of metal-bound peroxynitrite toward nitration of DTBP, peroxynitrite-bound MNIC 2 lacks phenol nitration reactivity toward DTBP. Presumably, the [(PMDTA)Fe] core in {Fe(NO)}(8) MNIC 2 provides a mononuclear template for intramolecular interaction between Fe-bound peroxynitrite and Fe-bound NO , yielding Fe-bound nitrite stabilized in the form of complex 3. This [(PMDTA)Fe]-core-mediated concerted peroxynitrite homolytic O-O bond cleavage and combination of the O atom with Fe- bound NO - reveals a novel and effective pathway for NO-to-NO2- transformation. Regarding the reported assembly of the dinitrosyliron unit (DNIU) [Fe(NO)(2)] in the biological system, this synthetic cycle highlights DNIU as a potential intermediate for nitric oxide monooxygenation activity in a nonheme iron system.
Evidence of preserved collagen in an Early Jurassic sauropodomorph dinosaur revealed by synchrotron FTIR microspectroscopy
(2017-01-31)
Lee, Yao-Chang
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Chiang, Cheng-Cheng
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Huang, Pei-Yu
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Chung, Chao-Yu
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Huang, Timothy D.
Fossilized organic remains are important sources of information because they provide a unique form of biological and evolutionary information, and have the long-term potential for genomic explorations. Here we report evidence of protein preservation in a terrestrial vertebrate found inside the vascular canals of a rib of a 195-million-year-old sauropodomorph dinosaur, where blood vessels and nerves would normally have been present in the living organism. The in situ synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectra exhibit the characteristic infrared absorption bands for amide A and B, amide I, II and III of collagen. Aggregated haematite particles (alpha-Fe2O3) about 6 similar to 8 mu m in diameter are also identified inside the vascular canals using confocal Raman microscopy, where the organic remains were preserved. We propose that these particles likely had a crucial role in the preservation of the proteins, and may be remnants partially contributed from haemoglobin and other iron-rich proteins from the original blood.
Fuzzy control design of a magnetically actuated optical image stabilizer with hysteresis compensation
(2009-04-01)
Tu, Tse-Yi
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Chao, Paul C. -P.
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Chiu, Chi-Wei
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Wang, Chun-Chieh
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Huang, Jeng-Shen
A fuzzy controller (FC) is designed for a magnetically actuated optical image stabilizer (OIS) in order to suppress the vibrations caused by hand shakings and hysteresis. To this end, the dynamic model of the OIS with consideration of hysteresis is first established, along with assuming the hand-shaking vibration as sinusoidal excitations. It is clearly shown that with capability of continuing parameter tuning, the FC is superior to the conventional PID for vibration suppression. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3068542]
Growth competition between layer-type and porous-type Cu3Sn in microbumps
(2017-12-01)
Chu, David T.
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Chu, Yi-Cheng
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Lin, Jie-An
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Chen, Yi-Ting
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Wang, Chun-Chieh
Experimental study of growth competition between the co-existing layer-type and porous-type Cu3Sn in solder microbumps of Cu/SnAg/Cu is reported. The thickness of the SnAg solder is about 14 pm and the Cu column on both sides is 20 pm. Upon wetting-reflow, the solder is reacted completely to form Cu Sn iptermetallic compounds in a multi-layered structure of Cu/Cu3Sn/Cu6Sn5/Cu3Sn/Cu. Upon further annealing at 220 degrees C and 260 C, we obtain Cu/Cu3Sn/porous Cu3Sn/Cu3Sn/Cu, in which both types of Cu3Sn co-exist and form an interface. In the layer-type growth, we assume Cu to be the dominant diffusing species, coming from the Cu column. The Cu reacts with Cu6Sn5 to grow the Cu3Sn layer. In the porous-type growth, we assume Sn to be the dominant diffusing species, coming from the depletion of Sn in Cu6Sn5. The depleted Cu6Sn5 transforms to the porous-type Cu3Sn. At the same time, the Sn diffuses to the side-wall of Cu column to form a coating of Cu3Sn. Experimental observations of 3-dimensional distribution of voids in the porous-type Cu3Sn are performed by synchrotron radiation tomography; the voids are interconnected for the out-diffusion of Sn. The competing growth between the layer-type and the porous-type Cu3Sn is analyzed. (C) 2017 Elsevier Ltd. All rights reserved.
Integrated Accelerometer with Capacitance to Digital Interface Circuit Design based on monolithic 0.18 mu m CMOS MEMS technology
(2012)
Wang, Chun-Chieh
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Fan, Long-Sheng
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Wen, Kuei-Ann
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
A monolithic accelerometer with integrated capacitance to digital readout circuit implemented in mixed-signal MEMS process is proposed to demonstrate sensor-to-bit integration. The sensing range is from -5g to 5g and the variation of the capacitance is from 441.2fF to 470fF. The sensitivity of the accelerometer is 2.88fF/g. The capacitance value of the sensing range is readout by the capacitance to digital circuit to readout. The capacitance to time circuit of the sensitivity is 6.94us/pF which is equivalent to 20ns/1bit. The digital output can be obtained without analog to digital module, and thus with power saving advantage, the output signal can be directly interface to digital signal process.
Investigation of post-annealing indium tin oxide for future electro-optical device application
(2011)
Ho, Ching-Yuan
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Tu, Tse-Yi
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Wang, Chun-Chieh
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Kang, Yuan
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電控工程研究所
The nanostructure transformation associated with electro-optical properties via post-annealing of indium tin oxide film (ITO) is investigated by increasing post-annealing temperature in ambient oxygen. Although oxygen vacancy and activation Sn ions contribute to conductivity of ITO film, the oxygen vacancy inevitably reduces during posting annealing, but Sn-O related bonds are oppositely increased with IR absorption at 790 cm(-1). Moreover, the sheet resistance of as-deposited ITO film 8.6 Omega/sq increases to 47 Omega/sq as the annealing temperature rises to 500 degrees C., the photoluminescence (PL) spectrum indicates that the oxygen vacancy plays a key role in dominating R-s in comparison with Sn-O bonds. The blue light transmittance of ITO film is slightly proportional to the annealing temperature due to phase crystallization enhancing band gap narrowing. Furthermore, as the annealing temperature rises beyond 500 degrees C, the transmittance is compromised between the Burstein-Moss effect of high carrier concentration and nanostructure crystallinity. The oxygen deficient vacancy, instead of Sn-O related bonds, is a major contribution for ITO conductivity and transmittance
Lattice distortion effect on elastic anisotropy of high entropy alloys
(2020-03-25)
Yen, Chao-Chun
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Huang, Guan-Rong
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Tan, Yun-Cheng
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Yeh, Han-Wen
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Luo, Da-Ji
The superior mechanical properties of high-entropy alloys (HEAs) have made an outstanding success in materials science and engineering. Studies to date have been devoted to what the severe lattice distortion induces. However, most researchers focus on its stimulation to plastic deformation instead of scrutinizing the variations on elasticity. Compared with conventional alloys, HEAs may perform disproportionate elasticity with uneven local lattice strain resulting from the severe lattice distortion. Therefore, it is necessary to survey its influence on the mechanical properties of HEAs systematically. In this study, the Lennard-Jones (LJ) potential, the embedded atom method (EAM) potential, and the modified embedded atom method (MEAM), are respectively conducted to investigate the lattice distortion effect on Young's modulus E (hkl) and Poisson's ratio nu (hkl, theta) along [100], [110], and [111] loading directions for several fcc metals composed of 1 similar to 5 atomic types, including Ni, Ni98W2, Ni96W4, FeCrNi, and CoNiCrFeMn HEAs. Also, a method is used to analyze the performance of the individual element on the elastic properties in the HEA environment. As a result, it can be unveiled that the effect of electron density inconsistency is more dominant than the effect of lattice distortion associated with the atomic size difference. The electronic configuration in the HEA environment plays a major role in elastic anisotropy while the difference of the atomic radii does the minor one. The anisotropy of CoNiCrFeMn HEA analyzed by this work is also consistent with in-situ neutron diffraction measurements. (C) 2019 Elsevier B.V. All rights reserved.
Micro-Layer and Lattice Structure Effects on Impedance of Titanium Oxide Phthalocyanine
(2018-07-01)
Lam, Tu-Ngoc
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Huang, Wei-Jie
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Wang, Chun-Chieh
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Chuang, Wei-Tsung
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Su, Ya-Wen
In this study, the authors employ synchrotron techniques to characterize multi-scale microstructure in elucidating how the modified crystal lattices at angstrom level and molecular stacking at micrometer scale of titanium oxide phthalocyanine (TiOPc) thin film tuning the impedance. The a and c lattice lengths of the TiOPc reveal a positive correlation with the impedance because of the - stacking distances of TiOPc molecules arrangements. Our results suggest a promising dip coating method to tailor the charge storage capability of TiOPc through controlling the crystal lattice sizes of TiOPc.
Multi-scale mapping for collagen-regulated mineralization in bone remodeling of additive manufacturing porous implants
(2019-05-15)
Tsai, Pei-I.
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Lam, Tu-Ngoc
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Wu, Meng-Huang
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Tseng, Kuan-Ying
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Chang, Yuan-Wei
Long term success of metallic fusion cages depends on mechanobiological processes through the bone incorporation and rich osseointegration. An optimal configuration of porous titanium-aluminum-vanadium (Ti-6Al-4V) implant fabricated via the additive manufacturing was evaluated in complimentary structure examinations to investigate the growth of autologous osseous at multi-length scales. X-ray microcomputed tomography (micro-CT) and transmission X-ray microscopy (TXM) using newly-built analysis method indicate the porous Ti-6Al-4V is much better for bone ingrowth compared to commercially non-porous titanium (Ti) and porous tantalum (Ta) implants at the ultramicrostructural level. The evolution of bone formation and remodeling acquired by nano X-ray Laue diffraction mapping exhibits the isotropic orientation and low crystallinity of all newly formed bone whereas mature bone in Ti-6Al-4V discloses the preferential alignment and higher crystallinity volumes of constituent hydroxyapatite (HA) crystallites. The high degree in mineral crystallinity of the fully mature bone suggests additive manufactured Ti-6Al-4V pores enhance the collagen-regulated mineralization.
NTP-PoCT: A conformance test tool for push-to-talk over cellular network
(2008-06-01)
Lin, Yi-Bing
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Wang, Chun-Chieh
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Lu, Chih-Hung
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Hsu, Miao-Ru
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資訊工程學系
This paper describes a conformance test tool for push-to-talk over cellular network developed on an Open Mobile Alliance Service Interoperability Test Platform. Based on the TTCN-3 specifications, we show how PoC test cases can be efficiently implemented on the test platform. Copyright (C) 2007 John Wiley & Sons, Ltd.
Structural characterization of colloidal crystals and inverse opals using transmission X-ray microscopy
(2014-07-15)
Huang, Bo-Han
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Wang, Chun-Chieh
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Liao, Chen-Hong
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Wu, Pu-Wei
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Song, Yen-Fang
A nondestructive tomographic technique was used to determine the crystallographic information of colloidal crystals comprising of polystyrene (PS) microspheres, as well as their silver inverse opals. The properties of the colloidal crystals, such as defects, grain size, grain boundaries, stacking sequence, and grain orientation, were determined using the full field transmission X-ray microscopy (TXM) with a spatial resolution of 50 nm. The PS microspheres (500-750 nm) which underwent a vertical electrophoresis process to form a face-centered cubic (fcc) close-packed structure with an ABCABC packing sequence. In addition, the colloidal crystal exhibited multiple grains, and an orientation variation of 6.1 degrees in the stacking direction between two neighboring grains. (C) 2014 Elsevier Inc. All rights reserved.