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The formation mechanism of Cd–S–Se quantum dots (QDs) with a CdS/CdSe core–shell structure within a silicate glass system was investigated by monitoring the change in the first excitonic absorption peak of CdSe, CdS, and Cd–S–Se QDs as a function of the heat‐treatment (HT) duration. When a silicate glass containing QD formation components for CdSe or CdS single‐phased QDs was heat‐treated, CdSe QDs grew via Ostwald ripening, whereas CdS QDs hardly formed within the given silicate glass matrix. When the glass, including CdO, ZnSe, and ZnS, was utilized for the synthesis of Cd–S–Se QDs within the glass matrix, Cd–S–Se QDs were successfully formed and exhibited similar growth behavior to CdSe QDs during the initial stage of HT. The structural changes in the QD‐embedded glasses during HT were also monitored by Raman spectroscopy and discussed, and a possible formation mechanism of CdSe/CdS core–shell‐structured QDs within silicate glasses is suggested. [ABSTRACT FROM AUTHOR]

Abstract In an effort to endow Ge-Sb-S sulfide glass with capability to transmit the long-wavelength infrared (LWIR) photons as well as to possess highly dispersive refractive indexes over the LWIR spectral range, we have compositionally adjusted ternary Ge-Sb-S glass prior to tuning quaternary Ge-X-Sb-S (X = Ga, Bi, In or Sn) glass. Among the constituent atoms of ternary Ge-Sb-S glass, Ge content turned out to exert the strongest influence not only on thermal and mechanical properties but also on infrared transmission edge. Specifically, glass transition temperature and Vickers hardness tended to be directly proportional to Ge content, but infrared transmission edge was blue-shifted upon increase of Ge content, simultaneously producing an additional multiphonon absorption peak at ~ 9 µm. As such, Ge-Sb-S glass containing Ge atoms less than ~ 15 at% was considered to feature applicability in LWIR range, which on the other hand suffers from relatively poor thermal and mechanical properties. In our experimental attempts on quaternary sulfide glasses performed to mitigate such deteriorations, presence of relatively small amount of Ga appeared to be most effective among the elements employed in this study as the fourth constituent. Moreover, only Ga atoms improved thermal stability with significantly increasing crystallization temperature. Quaternary Ge-Ga-Sb-S glass compositionally optimized in this study was then verified to be much more dispersive than typical Se-based chalcogenide glasses in the LWIR region. [ABSTRACT FROM AUTHOR]

In the present study, zinc‐molybdenum‐tellurite glasses are prepared and their thermal, thermo‐mechanical, viscous, and mechanical properties for mid‐IR molded glass lens applications are studied. From the thermal analysis, it is found that the glass transition temperature, onset crystallization temperature, and stability parameters slightly increase with an increase in ZnO content in both series of glasses. Thermal expansion coefficient decreases from 16.56 to 14.67 × 10−6 K−1 as the ZnO content increased from 10 to 30 mol%. For fixed 10 mol% of MoO3 content, Knoop hardness slightly decreases from 3009 to 2842 MPa as ZnO content increases from 10 to 30 mol% whereas it increases for 20 mol% of MoO3. The results indicate that the addition of ZnO and MoO3 contents into the tellurite glass system increases bridging oxygen contribution and in turn network compactness of tellurite matrix. [ABSTRACT FROM AUTHOR]

It was shown that the residual stress of the tetrahedral amorphous carbon (ta-C) thin film deposited on insulating material by filtered cathodic vacuum arc (FCVA) source can be controlled with mid-frequency pulse bias voltage. The residual stress of ta-C thin film decreased monotonically with the substrate pulse bias when the base material to be coated was insulating. There was not the apparent peak of residual stress about the substrate pulse bias which appeared for the electrically conducting base material. It was observed that the residual stress increased with the arc current and dielectric thickness at some pulse voltage range (100 V–1000 V). The sp 3 contents calculated by using Raman spectra and the surface hardness values as a function of substrate pulse voltage showed the similar trend with the residual stress values. For ta-C thin film deposited on the polished alumina sample, it was shown that the critical load in the scratch test decreased with the residual stress. The residual stress of ta-C on the insulating base material was explained with the change of the sheath voltage in the equivalent circuit model. [ABSTRACT FROM AUTHOR]

The thermal expansion coefficient ( TEC) of Ge-Sb-Se glass, within a compositional range suitable for molded lenses capable of transmitting long-wavelength infrared, was analyzed to assess compositional dependence. Unlike other thermal properties, eg, glass transition temperature and dilatometric softening temperature, which are correlated mostly with germanium content, the TEC turned out to behave most sensitively with selenium content. The thermal expansion behavior of this glass was evaluated based on two structural parameters: the mean coordination number and average bond energy ( ABE). It was verified that the relation between TEC and these structural parameters needs to be distinguished in terms of homopolar Se-Se bonds. Specifically, the TEC tends to decrease monotonically as the mean coordination number increases, and there are relatively small discrepancies between Se-sufficient and Se-deficient compositions. The TEC of the Se-sufficient glass appears to have a relatively well-defined correlation with the ABE: the TEC decreases as the ABE increases. However, a much weaker correlation between the TEC and ABE is observed in the Se-deficient glass. The observed thermal expansion behavior of this glass is delineated, with a particular focus on its connection to the structural role of the Se atoms. [ABSTRACT FROM AUTHOR]

As for the molded lens applications of ternary Ge–Sb–Se glass, Ge-rich compositions are normally preferable since thermal and mechanical properties are better in these compositions. In an effort to explicate thermal properties of such glasses suitable for practical molding process, we have evaluated their compositional dependence of glass transition temperature (T g ) and softening point temperature (T s ). Among three constituent atoms, Ge turns out to exert a most conspicuous correlation with T g and T s . This phenomenological behavior is then explained in connection with structural evolution induced by Ge. Based on analysis of mean coordination number and average bond energy, it is inferred that the glass structure becomes energetically more stable and topologically more connected with increasing Ge content. [ABSTRACT FROM AUTHOR]

Background: As the most abundant protein in human tissues, the use of collagen is essential in the fields of biological science and medicine.Objective: The aim of this study is to investigate the mechanical effect of pulsed laser irradiation on collagen tissue.Methods: With various laser parameters such as peak power, pulse width, and repetition rate, the induced stresses on samples were measured and analyzed. Monte Carlo simulation was performed to investigate the effect of laser parameters on the collagen sample.Results: The results indicated that the magnitude of mechanical stress could be controlled by various laser parameters.Conclusions: This study can be used in biostimulation for therapy and mechanoreceptor stimulation for tactile application. [ABSTRACT FROM AUTHOR]

Background: The evaluation and control of lighting is crucial in physiological, biomedical, and industrial fields. Many kinds of lighting techniques based on LED have been developed due to its advantages.Objective: The aim of this study is to develop the multi-colored LED system for healing purposes.Methods: Light source with three-color chip LEDs was investigated to detect the dominant wavelength.Results: The results show that the additive principle by three-color LEDs can be successfully applied to lighting system by generating a variety of colors.Conclusions: The results are expected to be useful in the field of light therapy and medicine. Applications of the developed light system are lighting therapies such as stimulating blood circulation and digestive processes, and controlling inflammation. [ABSTRACT FROM AUTHOR]

Background: Evaluation of joint movements is essential to choose an appropriate rehabilitation protocol for a patient.Objective: The aim of this study is to suggest an alternative optical technique for measurement of joint angle which is convenient, inexpensive, and can be operated in real time.Methods: According to the principle of the triangulation method, position sensitive detector (PSD) converts reflected light signals into distance-related voltages. Various parameters were investigated to increase detection range and resolution of joint angle measurements.Results: The accuracy of the suggested optical sensor was verified by comparing with a commercial goniometer and 3D motion capture system.Conclusions: This method can be applied to monitor recovery progress for the patient in rehabilitation and sport science. [ABSTRACT FROM AUTHOR]

For diagnostic and therapeutic purposes, the joint angle measurement of a patient after an accident or a surgical operation is significant for monitoring and evaluating the recovering process. This paper proposed an optical fiber sensor for the measurement of angular displacement. The effect of beveled fiber angle on the detected light signal was investigated to find an appropriate mathematical model. Beveled fiber tips redirected the light over a range of angles away from the fiber axis. Inverse polynomial models were applied to directly obtain and display the joint angle change in real time with the Lab-VIEW program. The actual joint angle correlated well with the calculated LabVIEW output angle over the test range. The proposed optical sensor is simple, cost effective, small in size, and can evaluate the joint angle in real time. This method is expected to be useful in the field of rehabilitation and sport science. [ABSTRACT FROM AUTHOR]

For diagnostic and therapeutic purposes, the joint angle measurement of a patient after an accident or a surgical operation is significant for monitoring and evaluating the recovering process. This paper proposed an optical fiber sensor for the measurement of angular displacement. The effect of beveled fiber angle on the detected light signal was investigated to find an appropriate mathematical model. Beveled fiber tips redirected the light over a range of angles away from the fiber axis. Inverse polynomial models were applied to directly obtain and display the joint angle change in real time with the Lab-VIEW program. The actual joint angle correlated well with the calculated LabVIEW output angle over the test range. The proposed optical sensor is simple, cost effective, small in size, and can evaluate the joint angle in real time. This method is expected to be useful in the field of rehabilitation and sport science. [ABSTRACT FROM AUTHOR]

We successfully fabricated Y2O3:RE3+ (RE = Eu, Tb, and Dy) core and core–shell nanophosphors by the molten salt method and sol–gel processes with Y2O3 core size of the order of 100~150 nm. The structural and morphological studies of the RE3+-doped Y2O3 nanophosphors are analyzed by using XRD, SEM and TEM techniques, respectively. The concentration and annealing temperature dependent structural and luminescence characteristics were studied for Y2O3:RE3+ core and core–shell nanophosphors. It is observed that the XRD peaks became narrower as annealing temperature increased in the core–shell nanophosphor. This indicates that annealing at higher temperature improves the crystallinity which in turn enhances the average crystallite size. The emission intensity and quantum yield of the Eu3+-doped Y2O3 core and core–shell nanoparticles increased significantly when annealing temperature is varied from 450 to 550 °C. No considerable variation was noticed in the case of Y2O3:Tb3+ and Y2O3:Dy3+ core and core–shell nanophosphors. [ABSTRACT FROM AUTHOR]

In this paper, the glass systems, TeO2–ZnO–BaO (TZB), TeO2–ZnO–BaO–Nb2O5 (TZB–Nb) and TeO2–ZnO–BaO–MoO3 (TZB–Mo), were fabricated by the traditional melt-quench protocol for use as mid-infrared (mid-IR) transmitting optical material. The effect of Nb2O5 and MoO3 on the key glass material properties was studied through various techniques. From the Raman analysis, it was found that the structural modification was clear with the addition of both Nb2O5 and MoO3 in the TZB system. The transmittance of studied glasses was measured and found that the optical window covered a region from 0.4 to 6 μm. The larger linear refractive index was obtained for the Nb2O5-doped TZB glass system than that of other studied systems. High glass transition temperature, low thermo-mechanical coefficient and high Knoop hardness were noticed in the Nb2O5-doped TZB glass system due to the increase in cross-linking density and rigidity in the tellurite network. The results suggest that the Nb2O5-doped TZB optical glasses could be a promising material for mid-infrared transmitting optics. [ABSTRACT FROM AUTHOR]

In an effort to augment thermal and mechanical properties of ternary Ge-Sb-Se glass for use in molded lens applications, mixed-chalcogen Ge 27.5 Sb 12.5 S x Se 60- x glasses have been investigated in this study with a particular attention paid to refractive index dispersion as well as infrared transmission edge. Changes in Vickers hardness, glass transition temperature, dilatometric softening temperature and thermal expansion coefficient are elucidated in terms of structural evolutions that sulfur induces. Infrared transmission edge blueshifts upon the addition of sulfur, which can be nicely interpreted in connection with average bond energy and molar mass of a given composition based on a postulation that this glass behaves as a single average harmonic oscillator in shaping multiphonon absorption. Refractive index at the long-wavelength infrared range becomes more dispersive with increasing sulfur content in these sulfur-selenide glasses, and thereby their dispersion can be pinpointed via adjusting S content. The Abbe diagram in the long-wavelength infrared region is extended towards the high-dispersion side, thus enhancing practicality of the chalcogenide glasses as in the form of lens and/or filter for the thermal imaging applications. [ABSTRACT FROM AUTHOR]