Experiments on chaos synchronization in two separate erbium-dopedfiber lasers

Chaos synchronization in two separate erbium-doped fiber lasers through a 1.5-km-long fiber is experimentally demonstrated. Two identical erbium-doped fiber lasers are fabricated and modulated by an optical modulator near the relaxation oscillation frequency of the fiber laser. At this frequency, the two fiber lasers generate chaotic carriers. When the synchronization conditions such as cavity length, modulation frequency, and laser characteristics are satisfied, the two chaotic fiber lasers are synchronized     

Soft X‐ray Ptychographic Imaging and Morphological Quantification of Calcium Silicate Hydrates (C–S–H)

Morphological details of calcium silicate hydrate (C–S–H) stemming from the hydration process of Portland cement (PC) phases are crucial for understanding the PC‐based systems but are still only partially known. Here we introduce the first soft X‐ray ptychographic imaging of tricalcium silicate (C₃S) hydration products. The results are compared using both scanning transmission X‐ray and electron transmission microscopy data. The evidence shows that ptychography is a powerful method to visualize the details of outer and inner product C–S–H of fully hydrated C₃S, which have fibrillar and an interglobular structure with average void sizes of 20 nm, respectively. The high‐resolution ptychrography image enables us to perform morphological quantification of C–S–H, and, for the first time, to possibly distinguish the contributions of inner and outer product C–S–H to the small angle scattering of cement paste. The results indicate that the outer product C–S–H is mainly responsible for the q^?3 regime, whereas the inner product C–S–H transitions to a q^?2 regime. Various hypotheses are discussed to explain these regimes.     

Determination of atomistic deformation of tricalcium silicate paste with high-volume fly ash

We examined the effect of incorporating high-volume fly ash on the atomic arrangement and interatomic deformation behavior of calcium silicate hydrates in tricalcium silicate paste upon exposure to external forces. The interatomic structural changes and strains under compressive load were assessed using synchrotron in situ high-energy X-ray scattering-based atomic pair distribution function analysis. Three different types of strains, which were (a) macroscopic strains from gauges on the surfaces of specimen, (b) strains in a reciprocal space (Bragg peak shift), and (c) strains in real space (PDF peak shift), were compared to each other. All monitored and calculated strains for tricalcium silicate-fly ash (50 wt% fly ash) paste were compared with the counterparts of the pure tricalcium silicate paste. Pair distribution function analysis in the range of r < 10 Å indicated that the atomic arrangement of tricalcium silicate-fly ash was similar to that of synthetic calcium silicate hydrates followed by that of pure tricalcium silicate paste. Moreover, the pair distribution function refinement results revealed that the calcium silicate hydrate structure in tricalcium silicate-fly ash paste was similar to tobermorite 11 Å, unlike that in pure tricalcium silicate paste. The interatomic strain of tricalcium silicate-fly ash in the real space (r < 20 Å) was smaller than that of tricalcium silicate under compression, which suggested that the incompressibility of calcium silicate hydrates at atomistic scale was enhanced by the incorporation of fly ash into it. This was likely to be caused by the increased silicate polymerization of calcium silicate hydrates, which was attributed to the increase in the amount of silicate in their structure via the addition of fly ash.     

Environmental Enrichment Enhances Cav 2.1 Channel-Mediated Presynaptic Plasticity in Hypoxic–Ischemic Encephalopathy

Hypoxic–ischemic encephalopathy (HIE) is a devastating neonatal brain condition caused by lack of oxygen and limited blood flow. Environmental enrichment (EE) is a classic paradigm with a complex stimulation of physical, cognitive, and social components. EE can exert neuroplasticity and neuroprotective effects in immature brains. However, the exact mechanism of EE on the chronic condition of HIE remains unclear. HIE was induced by a permanent ligation of the right carotid artery, followed by an 8% O₂ hypoxic condition for 1 h. At 6 weeks of age, HIE mice were randomly assigned to either standard cages or EE cages. In the behavioral assessments, EE mice showed significantly improved motor performances in rotarod tests, ladder walking tests, and hanging wire tests, compared with HIE control mice. EE mice also significantly enhanced cognitive performances in Y-maze tests. Particularly, EE mice showed a significant increase in Ca_v 2.1 (P/Q type) and presynaptic proteins by molecular assessments, and a significant increase of Ca_v 2.1 in histological assessments of the cerebral cortex and hippocampus. These results indicate that EE can upregulate the expression of the Ca_v 2.1 channel and presynaptic proteins related to the synaptic vesicle cycle and neurotransmitter release, which may be responsible for motor and cognitive improvements in HIE.     

Ensuring IT Consulting SERVQUAL and User Satisfaction: A Modified Measurement Tool

This paper provides the newly developed IT consulting SERVQUAL measurement tool. In an attempt to measure the IS customers' perceived quality of the consulting services they received, the researchers developed a diagnostic tool of SERVQUAL based on the solid theoretical background, which can specifically be applied to the IT consulting service sector. It is composed of 6 dimensions of reliability, responsiveness, assurance, empathy, process and education, and the former four are derived from IT SERVQUAL and the latter two are added to consider the characteristics of IT consulting service.To develop IT consulting SERVQUAL, 7 consultants having over the 10 years careers, 3 customers having much experienced of consulting service, and 2 professors majoring in MIS have examined the constructs and the items of questionnaires. And this research had been applied to 86 respondents of 42 different organizations that had received IT consulting services over 2 past years to ensure the validation of this tool. The correlation and the factor analyses were conducted for validation of the measurement tool.The results indicated that six different areas in the measurement tool are significantly related with level of the customer satisfaction in spite of their few problems in its validation and its application in the field will be helpful to identify their problems and make plans for advancement.     

An Optical Packet Addressing Scheme for Optical Packet Switched Networks Using RF Frequency Carrier Assignment

We propose an efficient optical packet addressing technique for optical packet-switched networks, where the pre-assigned RF frequency carriers are used to represent the packet addresses. It can simplify the control process of optical packet switching so that it results in reduced address processing time and smaller complexity of the packet address processor due to simple extraction of address information. We also analyze the performance of the proposed packet addressing scheme in the transmission aspect taking into account packet address wavelength beating and laser nonlinearity.     

Harvesting of <Emphasis Type="Italic">Scenedesmus obliquus</Emphasis> cultivated in seawater using electro-flotation

Seawater, when supplemented to a growth medium, appears to stimulate auto-flocculation of a certain microalgae species like Scenedesmus obliquus and thus renders its harvesting easy. To make use of this unique response for the purpose of biomass harvesting, S. obliquus was grown in a seawater-added medium and then collected in electrochemically- mediated ways. Significantly higher harvesting efficiency and energy saving were observed with electroflotation (EF) than with electro-coagulation-flotation (ECF) and the standard BG11 medium. An optimal EF condition, the highest recovery rate with least energy use, was found with a supply of 0.5 A. Seawater amendment was most beneficial in a level of 10%. All this clearly showed that applying EF to cells cultivated in the seawater-supplemented medium is a promising harvesting means that enables one to obtain algae biomass without interfering with the downstream process of biodiesel production.     

Safe arm design with MR-based passive compliant joints and visco—elastic covering for service robot applications

In this paper a safe arm with passive compliant joints and visco—elastic covering is designed for human-friendly service robots. The passive compliant joint (PCJ) is composed of a magnetorheological (MR) damper and a rotary spring. In addition to a spring component, a damper is introduced for damping effect and works as a rotary viscous damper by controlling the electric current according to the angular velocity of spring displacement. When a manipulator interacts with human or environment, the joints and cover passively operate and attenuate the applied collision force. The force attenuation property is verified through collision experiments showing that the proposed passive arm is safe in view of some evaluation measures.     

Performance Comparison of a SSVEP BCI Task by Individual Stereoscopic 3D Susceptibility

This study aimed at investigating the differences in brain–computer interface (BCI) task performance between 2D and 3D displays depending on their individual susceptibility to stereoscopic 3D. Eleven female and 10 male participants attempted a steady-state visually evoked potential BCI navigation task in a virtual home environment with and without 3D views. Participants were categorized into fatigued and unfatigued groups, depending on their individual susceptibility to 3D, which was characterized using a subjective evaluation method for 3D visual fatigue. The task completion time for the fatigued group under the 3D conditions was significantly delayed relative to the 2D mode. In contrast, a significantly decreased completion time was observed in the 3D view relative to the 2D view for the unfatigued group. The averaged positive predictive value significantly increased in the 3D mode relative to the 2D one for the unfatigued group only. These results are expected to provide a practical implication for enhancing BCI task performance in light of individual vulnerability to 3D.     

Effects of molar substitution of AA pendant on poly(MMA-co-GMA) under UV curing

The molar substitution of an acrylic acid (AA) pendant group on a glycidyl methacrylate–methyl methacrylate copolymer was investigated to evaluate its affects on mechanical properties and thermal stability under UV curing. Structural analysis was conducted by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy (¹H-NMR) to study the synthetic route of the acrylate copolymer. The mechanical behaviors of AA substituted copolymers were interpreted in terms of both their loss tangent and elongation at the break point, because AA increases the cross-linking density, which is directly proportional to the degree of homopolymerization; this relationship was monitored by ¹H-NMR with various molar substitutions. In addition, the optical and mechanical properties of the copolymers were also characterized by the extent of AA molar substitution. The optimal behavior was obtained at a molar substitution of 94.3% (equivalent to an AA/GMA molar ratio of 1.4) and satisfied both the transparency (>89.3%) and elongation (>7.4%) requirements for the complex-shaped coatings.