Real-Time Weld Quality Prediction Using a Laser Vision Sensor in a Lap Fillet Joint during Gas Metal Arc Welding.

Nondestructive test (NDT) technology is required in the gas metal arc (GMA) welding process to secure weld robustness and to monitor the welding quality in real-time. In this study, a laser vision sensor (LVS) is designed and fabricated, and an image processing algorithm is developed and implemented to extract precise laser lines on tested welds. A camera calibration method based on a gyro sensor is used to cope with the complex motion of the welding robot. Data are obtained based on GMA welding experiments at various welding conditions for the estimation of quality prediction models. Deep neural network (DNN) models are developed based on external bead shapes and welding conditions to predict the internal bead shapes and the tensile strengths of welded joints.

Screening study for genetic polymorphisms affecting pharmacokinetics of talniflumate.

Talniflumate is a phthalidyl ester of niflumic acid, which has potent analgesic and anti-inflammatory effects and is widely used to treat inflammatory disorders, such as rheumatoid arthritis. To screen the possible genetic factors affecting the pharmacokinetics (PK) of talniflumate, 23 male Korean volunteers were enrolled from two separate bioequivalence studies. All subjects received 740 mg (two tablets) talniflumate in a standard 2×2 cross-over model in a randomized order. For the genetic study, PK parameters of the reference drug were used. We used Illumina Human610Quad v1.0 DNA Analysis BeadChip for whole genome single nucleotide polymorphism (SNP) analysis and whole genome genotyping data were processed by linear regression analysis for PK parameters. Whole genome analysis revealed 1498 significant SNPs (P < 0.0001) for Cmax, 65 significant SNPs (P < 0.0001) for T max, and 1491 significant SNPs (P < 0.0001) for AUC inf. For clinical pharmacological purposes, we selected SNPs from drug metabolizing enzymes and transporters, and analyzed the PK parameters of various genotypes. Two SNPs (rs11165069 from ABCA4 (p=0.00002); rs17847036 from CYP2C9 (p=0.000001)) showed significant associations with talniflumate C max. In the T max group, two SNPs (rs3787555 from CYP24A1 (p=0.00035); rs2275034 from ABCA4 (p=0.000587)) showed significant associations with talniflumate T max. In the AUC inf group, two SNPs (rs11165069 from ABCA4 (p=0.00002); rs12461006 from SLC1A6 (p=0.00008)) exhibited significant associations with talniflumate absorption. These results show that genetic factors could affect the PK parameters, and provide information that may be used in the development of personalized talniflumate therapy.

Disordered nanostructures by hole-mask colloidal lithography for advanced light trapping in silicon solar cells.

We report on the fabrication of disordered nanostructures by combining colloidal lithography and silicon etching. We show good control of the short-range ordered colloidal pattern for a wide range of bead sizes from 170 to 850 nm. The inter-particle spacing follows a Gaussian distribution with the average distance between two neighboring beads (center to center) being approximately twice their diameter, thus enabling the nanopatterning with dimensions relevant to the light wavelength scale. The disordered nanostructures result in a lower integrated reflectance (8.1%) than state-of-the-art random pyramid texturing (11.7%) when fabricated on 700 µm thick wafers. When integrated in a 1.1 µm thin crystalline silicon slab, the absorption is enhanced from 24.0% up to 64.3%. The broadening of resonant modes present for the disordered nanopattern offers a more broadband light confinement compared to a periodic nanopattern. Owing to its simplicity, versatility and the degrees of freedom it offers, this potentially low-cost bottom-up nanopatterning process opens perspectives towards the integration of advanced light-trapping schemes in thin solar cells.

Color filter incorporating a subwavelength patterned grating in poly silicon.

A color filter based on a subwavelength patterned grating in poly silicon was proposed and realized on a quartz substrate. It was produced by utilizing the laser interference lithography technique to feature wide effective area compared to the costly e-beam lithography. An oxide layer was introduced on top of the silicon grating layer as a mask to facilitate the silicon-etching and to enhance the filtering selectivity as well. The structural parameters for the device include the grating pitch and height of 450 nm and 100 nm respectively, the silicon stripe width of 150 nm, and the oxide thickness of 200 nm. The fabricated device offered a spectral response suitable for a blue color filter, exhibiting the center wavelength of approximately 460 nm, the bandwidth approximately 90 nm and the peak transmission 40%. The positional dependence of its performance was examined to find the effective area of 3 x 3 mm(2), where the variation in the relative transmission efficiency and in the center wavelength was less than 10% and 2 nm respectively. Finally, the influence of the angle of the incident beam upon the transfer characteristics of the device was investigated to reveal that the rate of change in the relative transmission was equivalent to about 1.5%/degree.

Color filter based on a subwavelength patterned metal grating.

A color filter incorporating a subwavelength patterned grating in a metal film perforated with a square array of circular apertures on a quartz substrate was accomplished. Its performance was enhanced by applying a dielectric overlay to the grating layer so as to match the refractive indices of the media on either side of it. The device was designed by utilizing the finite-difference time-domain method and implemented by adopting the electron-beam direct-writing technique. Two different devices were fabricated with the structural parameters: the grating height of 50 nm and the pitch of 340 nm for the red color and 260 nm for the green color. For the red color filter the center wavelength was 680 nm and the peak transmission 57%, while for the green color one the center wavelength was 550 nm and the peak transmission 50%. It was confirmed the introduction of the index matching overlay led to an increase of ~15% in the transmission efficiency and helped combine double bands into a single dominant band as well, thereby improving the color selectivity of the filter.

Light extraction enhancement from nano-imprinted photonic crystal GaN-based blue light-emitting diodes.

The nano-imprint lithography method was employed to incorporate wide-area (375 x 330 mum(2)) photonic-crystal (PC) patterns onto the top surface of GaN-based LEDs. When the 280-nm-thick p-GaN was partly etched to ~140 nm, the maximal extraction-efficiency was observed without deteriorating electrical properties. After epoxy encapsulation, the light output of the PC LED was enhanced by 25% in comparison to the standard LED without pattern, at a standard current of 20 mA. By three-dimensional finite-difference time-domain method, we found that the extraction efficiency of the LED tends to be saturated as the etch-depth in the GaN epitaxial-layer becomes larger than the wavelength of the guided modes.

Robust regression-based analysis of drug-nucleic acid binding.

Outlier detection can be very important in analyzing data from Scatchard plots. In this study, a robust (outlier-resistant) regression procedure was used in conjunction with a Scatchard plot to study the binding of the methylphenazinium cation with double-stranded DNA. The procedures, their results, and their advantages are discussed.