Adhesive Joining Technology for Manufacturing of the Composite Flexspline for a Harmonic Drive

A new manufacturing method for the cup-type composite flexsplinc drive was developed using adhesive joining technology to obviate the manufacturing difficulty of the conventional one-piece cup-type steel flexspline and to improve the dynamic characteristics of the flexspline.

In this method, the boss, tube and tooth sections of the flexspline were designed and manufactured separately, and adhesively bonded. The tube section was manufactured with high strength carbon fiber epoxy composite material and its dynamic properties were compared with those of the conventional steel flexspline.

The torque transmission capability of the adhesively-bonded joint was numerically calculated using the nonlinear shear stress-strain relationship which was represented by an exponential form.

From the test results of the manufactured composite flexspline and the conventional flexspline, it was found that the manufactured composite flexspline had better torque transmission characteristics. Also, it was found that the damping capacity of the composite flexspline was considerable improved.     

Sound transducer calibration of ambulatory audiometric system utilizing delta learning rule

An efficient calibration algorithm for an ambulatory audiometric test system is proposed. This system utilizes a personal digital assistant (PDA) device to generate the correct sound pressure level (SPL) from an audiometric transducer such as an earphone. The calibrated sound intensities for an audio-logical examination can be obtained in terms of the sound pressure levels of pure-tonal sinusoidal signals in eight-banded frequency ranges (250, 500, 1 000, 2 000, 3 000, 4 000, 6 000 and 8 000 Hz), and with mapping of the input sound pressure levels by the weight coefficients that are tuned by the delta learning rule. With this scheme, the sound intensities, which evoke eight-banded sound pressure levels by 5 dB steps from a minimum of 25 dB to a maximum of 80 dB, can be generated without volume displacement. Consequently, these sound intensities can be utilized to accurately determine the hearing threshold of a subject in the ambulatory audiometric testing environment.     

Synthesis of Uniquely Structured SnO2 Hollow Nanoplates and Their Electrochemical Properties for Li‐Ion Storage

A new mechanism for the transformation of nanostructured metal selenides into uniquely structured metal oxides via the Kirkendall effect, which results from the different diffusion rates of metal and Se ions and O₂ gas, is proposed. SnSe nanoplates are selected as the first target material and transformed into SnO₂ hollow nanoplates by the Kirkendall effect. SnSe‐C composite powder, in which SnSe nanoplates are attached or stuck to amorphous carbon microspheres, transforms into several tens of SnO₂ hollow nanoplates by a thermal oxidation process under an air atmosphere. Core–shell‐structured SnSe‐SnSe₂@SnO₂, SnSe₂@SnO₂, Se‐SnSe₂@SnO₂, and Se@SnO₂ and yolk–shell‐structured Se@void@SnO₂ intermediates are formed step‐by‐step during the oxidation of the SnSe nanoplates. The uniquely structured SnO₂ hollow nanoplates have superior cycling and rate performance for Li‐ion storage. Additionally, their discharge capacities at the 2nd and 600th cycles are 598 and 500 mA h g^‐1, respectively, and the corresponding capacity retention measured from the 2nd cycle is as high as 84%.     

Highly Aligned Plasmonic Gold Nanorods in a DNA Matrix

Since the Lycurgus Cup was made in the 4th century, metal nanoparticles have attracted much interest due to the characteristics of the plasmonic and metamaterials that show beautiful colors. Despite these fascinating properties, the practical use is limited because it is difficult to control the orientation of the plasmonic nanoparticles. Here, highly aligned plasmonic gold nanorods are obtained using self‐assembled DNA material. Simple mechanical shearing results in long‐range DNA–gold nanorod arrays which show parallel, perpendicular, and zigzag configurations due to the competition between the shear force and DNA elasticity. The resulting surface plasmonic resonance properties of the aligned DNA–gold nanorods film show highly polarization‐dependent behavior in a large area, which is critical for optical and photonic applications. This simple way to form anisotropic plasmonic films can be used for plasmonic nanoparticles in potential applications such as displays and sensors.     

Two Regioisomeric π‐Conjugated Small Molecules: Synthesis,Photophysical, Packing,and Optoelectronic Properties

Two regioisomeric D₁‐A‐D‐A‐D₁ type π‐conjugated molecules (1,4‐bis{5‐[4‐(5‐fluoro‐7‐(5‐hexylthiophen‐2‐yl)benzo[c ][1,2,5]thiadiazole)]­thiophen‐2‐yl}‐2,5‐bis(hexyldecyloxy)benzene (Prox‐FBT) and 1,4‐bis{5‐[4‐(6‐fluoro‐7‐(5‐hexylthiophen‐2‐yl)benzo[c ][1,2,5]thiadiazole)]­thiophen‐2‐yl}‐2,5‐bis(hexyldecyloxy)benzene (Dis‐FBT)) are synthesized, by controlling the fluorine topology to be proximal or distal relative to the central core. The different F geometries are confirmed by the ¹H–¹H nuclear Overhauer effect spectroscopy (NOESY). Clearly different optical, electrochemical, and thermal transition behaviors are obtained, i.e., stronger absorption, deeper valance band (by ≈0.2 eV), and higher melting/recrystallization temperatures (by 7–20 °C) are observed for Dis‐FBT. The different intermolecular packing and unit cell structures are also calculated for the two regioisomers, based on the powder X‐ray diffraction and 2D grazing‐incidence wide‐angle X‐ray diffraction measurements. A tighter π–π packing with a preferential monoclinic face‐on orientation is extracted for Dis‐FBT, compared to Prox‐FBT with bimodal orientations. Different topological structures significantly affect the electrical and photovoltaic properties, where Prox‐FBT shows higher parallel hole mobility (2.3 × 10^?3 cm² V^?1 s^?1), but Dis‐FBT demonstrates higher power conversion efficiency (5.47%) with a larger open‐circuit voltage of 0.95 V (vs 0.79 V for Prox‐FBT). The findings suggest that small changes in the topological geometry can affect the electronic structure as well as self‐assembly behaviors, which can possibly be utilized for fine‐adjusting the electrical properties and further optimization of optoelectronic devices.     

Ultrasonic thermoforming of a large thermoplastic polyurethane film with the aid of infrared heating

This study concerns ultrasonic thermoforming of Thermoplastic polyurethane (TPU) film for the fabrication of a television speaker diaphragm. The speaker diaphragm has a convex-protruded feature with a rounded-rectangular shape on which a number of micro-corrugations are formed for sound quality improvement. This diaphragm has generally been manufactured out of thin TPU film using a thermoforming process, which required cycle time as long as several minutes for proper heating and cooling of the polymer film and mold. In this study, an ultrasonic thermoforming process was introduced to reduce the cycle time to fabricate the diaphragm by taking advantage of the rapid and localized heating capability of ultrasonic vibration energy. To improve the forming quality of a large diaphragm for a television speaker, infrared heating was added to the process to preheat the TPU film before the forming stage. Various processing parameters including ultrasonic thermoforming and infrared heating conditions were investigated in relation to the forming quality. As a consequence, the diaphragm could be fabricated with acceptable forming ratios (> 95 % in the band region and > 70 % in the micro-corrugations) and short cycle time (12 s). This means that the proposed process is superior to conventional thermoforming processes that require long cycle time (> 200 s).     

A new method for reducing VOCs formation during crude oil loading process

This study investigates the process of loading crude oil onto a tanker and the associated formation of Volatile organic compounds (VOCs). The main goal is to find mechanisms for reducing the amount of VOCs formation during the loading process. Different cases with a combination of a swirl unit and a U-bend were examined. Computational fluid dynamics (CFD) method was used to simulate the cavitation phenomenon, fluid flow pattern, and VOCs formation inside a loading pipeline. An experimental study was also done to investigate the accuracy of the numerical approach and to test the designed swirl units. Based on the numerical and experimental studies, a new approach is presented to reduce the VOCs formation notably during the loading process. The proposed approach can reduce the amount of VOCs formation by around 90 %, which can help to reduce the amount of wasted crude oil and also protect the atmosphere from gas emissions.     

Influence Plots for LASSO

With many predictors in regression, fitting the full model can induce multicollinearity problems. Least Absolute Shrinkage and Selection Operation (LASSO) is useful when the effects of many explanatory variables are sparse in a high‐dimensional dataset. Influential points can have a disproportionate impact on the estimated values of model parameters. This paper describes a new influence plot that can be used to increase understanding of the contributions of individual observations and the robustness of results. This can serve as a complement to other regression diagnostics techniques in the LASSO regression setting. Using this influence plot, we can find influential points and their impact on shrinkage of model parameters and model selection. We illustrate the methods with two examples. Copyright © 2016 John Wiley & Sons, Ltd.     

High‐Resolution Spin‐on‐Patterning of Perovskite Thin Films for a Multiplexed Image Sensor Array

Inorganic–organic hybrid perovskite thin films have attracted significant attention as an alternative to silicon in photon‐absorbing devices mainly because of their superb optoelectronic properties. However, high‐definition patterning of perovskite thin films, which is important for fabrication of the image sensor array, is hardly accomplished owing to their extreme instability in general photolithographic solvents. Here, a novel patterning process for perovskite thin films is described: the high‐resolution spin‐on‐patterning (SoP) process. This fast and facile process is compatible with a variety of spin‐coated perovskite materials and perovskite deposition techniques. The SoP process is successfully applied to develop a high‐performance, ultrathin, and deformable perovskite‐on‐silicon multiplexed image sensor array, paving the road toward next‐generation image sensor arrays.