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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.technovation.2010.03.004 Byline: Hsiu-Ling Li, Ming-Je Tang Keywords: Vertical integration; Innovative performance; Organizational learning; External knowledge sourcing Abstract: We set out in this study to analyze the impact of vertical integration on the innovative performance of a firm and to explore the interaction between vertical integration and different modes of external knowledge sourcing. Our empirical results reveal an initial increase in the effect of vertical integration on innovative performance up to a certain level of integration, although this is subsequently followed by a decline; that is, the relationship is characterized by an inverted U-shape. The results further reveal that external knowledge sourcing is positively related to the innovative performance of a firm, albeit with a negative interaction with the level of vertical integration. In other words, firms with higher levels of vertical integration may be faced with barriers to the acquisition of external knowledge. Our findings suggest that firms should be cautious in their pursuit of a strategy of vertical integration, given the non-monotonic impact on innovative performance, whilst an increase in the level of vertical integration is also likely to diminish the effectiveness of the external knowledge sourcing. Author Affiliation: Department of International Business, National Taiwan University, Taipei 106, Taiwan

Rotor and its corresponding system play an important role in a precision machine. However, accuracy deterioration, machine damage, or malfunction could also happen to the machine due to various abnormalities of the rotor system. Thus, a monitoring system that can early detect and identify abnormalities so that proper actions can be taken to ensure the machine works properly is necessary. In this study, fault diagnosis/monitoring method that can online monitor the three major abnormalities (impact by unusual force, abnormal friction and unbalanced rotation) of a rotor system was developed. Both of wavelet transform and fast Fourier transform were employed in the method to analyse the permanent change and transient change of system vibration signals for abnormality diagnosis. Characteristic values of converted vibration signals of a rotor system were calculated and used to form a diagnosis map. Subsequently, occurrence possibility of an abnormality can be predicted with the use of the degree of approach model. To verify the proposed monitoring method and system, both simulation and experiments were conducted. The results have shown high feasibility and reliability of the detection system.

The polarization dependence of directional couplers (DC) formed by silicon-on-insulator (SOI) slot waveguides was studied, and its applications as highly efficient polarization beam splitters (PBSs) and polarization-independent directional couplers (PIDCs) were investigated. The coupling lengths for the quasi-TE and quasi-TM modes may vary with the waveguide geometry due to structural birefringence; thus numerical simulations of the coupling effects in the directional couplers with different aspect ratios and waveguide spacing were conducted to obtain the optimal design parameters for high efficiency as well as compact device size. The lengths of the coupling regions of the designed PBS and PIDC are 47.61 and 23.13?μm, respectively, and they delivered good performance, with an extinction ratio greater than 20 and 1?dB bandwidth larger than 100?nm. The tolerance of fabrication error in the practical device is also discussed.

We show, to the best of our knowledge, the first simulation result of the strong plasmonic field coupling and enhancement at the Ag/Si interface of a silver core/protruded silicon shell nanocylinder by using the finite-element method. The strong plasmon field, with a slow effective phase velocity accumulated at the Ag/Si interface, which results from the large effective index of the surface plasmon due to the nearly identical real parts with opposite signs of the permittivities of silver and silicon at 633nm, is analyzed. When the silicon shell has shallow protrusions of proper periodicity to meet the phase matching condition between the incident light and the surface plasmon wave at the Ag/Si interface, a higher scattered electric field and a higher sensitivity to the refractive index change of the surrounding medium can be achieved. Furthermore, a feasible implementation of the core–shell nanocylinder design concept is studied and discussed.

A hexagonal nanostructure formed by seven core shell nanocylinders filled with different dielectric cores is investigated. The surface plasmon resonance in such a hexagonal nanostructure under conditions of different illumination wavelengths, dielectric cores, angles of incidence, and thicknesses of silver shells is studied by use of the finite element method. Simulation results show that the resonant wavelength is redshifted as the dielectric constant and the size of the core increase. The peak resonant wavelength and the local field enhancement are approximately proportional to the radius of the dielectric core. Additionally, the surface plasmon field excited by TM-polarized light at the incident angle of θ=15° is exactly a linear combination of those excited at incident angles of θ=0° and 30°, confirming the linear nature of the surface plasmon resonance in a nanostructure formed by linear media.

We conducted this experiment to assess the effect of saline injection in electrochemical therapy. Platinum electrodes using direct current were inserted into egg white or liver parenchyma. Pure water or 0.9%, 3%, or 26% sodium chloride were injected into various objects to compare with the control group (no injection). Power was set at 10 V. In the egg-white experiment, gas bubbles and coagulated protein developed around the electrodes. In ex vivoliver, frothy reddish debris developed around the cathodes, while a hardening and shrunken surface occurred around the anodes. The pH was 14 around the cathodes, 0 around the anodes. The electric current, the amount of coagulated protein, and the severity of tissue damage were all in proportion to the concentrations of the injected saline. The volume destroyed in the 26% saline group was 8.1 times larger than that of the control group. Therefore, injected saline, especially saturated saline, can enhance the effect of electrochemical therapy.