Spin-stretching of DNA and protein molecules for detection by fluorescence and atomic force microscopy

We have developed a rapid and efficient way of stretching DNA and denatured protein molecules for detection by fluorescence microscopy and atomic force microscopy (AFM). In the described method, a viscous drag created by transient rotational flow stretches randomly coiled DNA molecules or denatured proteins. Stretching is achieved by dispensing a droplet of sample solution containing DNA or denatured protein on a MgCl2-soaked mica surface. We present fluorescent images of straightened lambdaDNA molecules and AFM images of stress-shared, reduced von Willebrand factor as well as straightened lambdaDNA. The described quick and reliable spin-stretching technique will find wide applications in the analysis of single biopolymer molecules.     

The edge-cracking of AISI 304 stainless steel during hot-rolling

The hot-rolled plates of AISI 304 stainless steel, containing edge cracks of different intensities, were examined. The austenitic matrix of the steel contained small amounts of ferrite inhomogeneously distributed across the width and the thickness of the plate. A correlation was found between ferrite content and edge cracking: the higher the ferrite content the longer the edge cracks. Among the chemical elements present in the steel, the most critical effect on ferrite content was exerted by carbon and nitrogen. The longest edge cracks were observed for plates with the lowest content of carbon and nitrogen. A possible contribution of steel chemistry and heating temperature to changes in the steel phase composition and the probability of edge cracking is discussed.     

Concentration characteristics of atmospheric PCBs for urban and rural area, Korea

Mean concentrations of total PCBs (gas+particle) detected in urban and rural atmospheres were 130.41+/-62.57 pg/m(3) and 39.65+/-34.04 pg/m(3), respectively. The concentration distribution of PCB homologs in the urban and rural area decreased with increasing Cl substitutions and showed significant correlation coefficients (P>0.05) with the octanol-air partition coefficient (K(OA)) and vapor pressure, respectively. The fractions (%) of total PCBs were 28% for tri-CBs, 25% for tetra-CBs and 24% for penta-CBs in urban air and 45% for tri-CBs, 24% for tetra-CBs, and 21% for penta-CBs in rural air. The sum of those homologs was 77% for urban and 90% for rural air. Therefore, these homologs were identified as the main components of PCB homologs compared to other homologs (>penta-CBs). The Clausius-Clapeyron (CC) plot was applied to atmospheric PCB data, relating PCB partial vapor pressure (logarithm P) to inverse absolute temperature (1/T). The slopes obtained from Clausius-Clapeyron plots were -3888 (R(2)=0.75, P<0.0001) for urban and -1902 (R(2)=0.22, P<0.1) for rural air. The slope for urban air was approximately two times higher than that of rural air, possibly because the atmospheric concentration of lower molecular weight congeners in urban air may be predominantly influenced by local sources relative to rural air.     

State-of-charge estimation of lead-acid batteries using an adaptive extended Kalman filter

Lead-acid batteries are widely used in conventional internal-combustion-engined vehicles and in some electric vehicles. In order to improve the longevity, performance, reliability, density and economics of the batteries, a precise state-of-charge (SoC) estimation is required. The Kalman filter is one of the techniques used to determine the SoC. This filter assumes an a priori knowledge of the process and measurement noise covariance values. Estimation errors can be large or even divergent when incorrect a priori covariance values are utilized. These estimation errors can be reduced by using the adaptive Kalman filter, which adaptively modifies the covariance. In this study, an adaptive extended Kalman filter (AEKF) method is used to estimate the SoC. The AEKF can reduce the SoC estimation error, making it more reliable than using a priori process and measurement noise covariance values.     

Synthesis and electroluminescent properties of blue-emitting t-butylated bis(diarylaminoaryl)anthracenes for OLEDs

A new series of blue fluorescent emitters based on t-butylated bis(diarylaminoaryl) anthracenes were synthesized and their electroluminescent properties investigated. Into these blue materials, t-butyl groups were introduced to both prevent molecular aggregation between the blue emitters through steric hindrance and reduce self-quenching. As such, this would contribute to overall improvement in OLED efficiency. To explore the electroluminescent properties of these materials, multilayered OLEDs were fabricated into a device structure of: ITO/NPB(50 nm)/blue emitters doped in ADN(30 nm)/Alq₃(20 nm)/Liq(2 nm)/Al(100 nm). All devices showed efficient blue emissions. In particular, one device exhibited highly efficient sky blue emissions with a maximum luminance of 11,060 cd/m² at 12.0 V and respective luminous and power efficiencies of 6.59 cd/A and 2.58 lm/W at 20 mA/cm². The peak wavelength of the electroluminescence was 468 nm with CIEx,y coordinates of (0.159, 0.198) at 12.0 V. In addition, a deep blue device with CIEx,y coordinates of (0.159, 0.151) at 12.0 V showed a luminous efficiency of 4.2 cd/A and power efficiency of 1.66 lm/W at 20 mA/cm².     

A fully integrated 33.8-dBm bulk CMOS T/R switch with a negative-voltage switch controller

This paper presents a single-pole double-throw CMOS transmit/receiver (T/R) switch in a standard 0.18 μm CMOS process. The T/R switch uses 6-stacked body-floated N-MOSFETs to enhance linearity, and a negative-voltage controller integrated on a single die with the power switch cell. A complementary DICSON charge pump is employed to generate the negative voltages and three-step level shifters are used to control the switch cell. The fabricated T/R switch has P_1dB of 33.8 and 32.6 dBm at 900 and 1,800 MHz from a 2 V supply, respectively. The insertion losses of TX are 0.7 and 1.1 dB at 900 and 1,800 MHz, respectively. The isolations from TX to ANT and RX to ANT are >25 dB at both frequencies, and the return losses are >20 dB. The proposed T/R switch shows comparable or better performance compared to the previously reported T/R switches without the switch controller.     

Parallel Density-Based Spatial Clustering with Dual-Functional Memristive Crossbar Array

Analog and digital switching performances in a Ta/HfO₂/RuO₂ (THR) memristor are studied to implement a density-based spatial clustering of applications with noise (DBSCAN) algorithm in a low-power, parallel-computing memristor crossbar structure. In the analog mode THR memristor, more than 256 states can be stored through a fine-tuning process with a denoising scheme. The analog mode crossbar array facilitates Euclidean distance calculation between any points in the given graphic dataset. In the digital mode, the on/off ratio of more than three orders of magnitude between the binary states is achieved, providing functionality to cluster the data points with a reduced number of operations. The parallel computing capacity of the adopted crossbar decreases the time complexity of the original DBSCAN from O(n²) to O(n). Through array-level simulations, the effectiveness of hardware functionality is validated using representative synthetic datasets and single-cell RNA sequences datasets.     

Effect of pressure on surface passivation of silicon solar cell by forming gas annealing

Forming gas annealing (FGA) of single crystalline commercial silicon solar cell was carried out at various conditions of temperature, pressure, time, and gas ratio for different samples. We report here the role of working pressure during annealing to improve the performance of the solar cells. The improvement basically comes from the surface passivation. It was found that the annealing of solar cells at high temperature in forming gas ambient could bring improvement in conversion efficiency only if the process pressure is sufficient to suppress the out diffusion of hydrogen from the silicon nitride layer that acts as anti-reflection coating. The outcome of this experiment can be instrumental in providing guidelines for improving the low grade commercial cells by introducing an easy and low cost step of forming gas annealing in appropriate condition.     

Molecular Engineering of Blue Fluorescent Molecules Based on Silicon End‐Capped Diphenylaminofluorene Derivatives for Efficient Organic Light‐Emitting Materials

Blue fluorescent materials based on silicone end‐capped 2‐diphenylaminofluorene derivatives are synthesized and characterized. These materials are doped into a 2‐methyl‐9,10‐di‐[2‐naphthyl]anthracene host as blue dopant materials in the emitting layer of organic light‐emitting diode devices bearing a structure of ITO/DNTPD (60 nm)/NPB (30 nm)/emitting layer (30 nm)/Alq₃ (20 nm)/LiF (1.0 nm)/Al (200 nm). All devices exhibit highly efficient blue electroluminescence with high external quantum efficiencies (3.47%–7.34% at 20 mA cm^?2). The best luminous efficiency of 11.2 cd A^?1 and highest quantum efficiency of 7.34% at 20 mA cm^?2 are obtained in a device with CIE coordinates (0.15, 0.25). A deep‐blue OLED with CIE coordinates (0.15, 0.14) exhibits a luminous efficiency of 3.70 cd A^?1 and quantum efficiency of 3.47% at 20 mA cm^?2.