4,248 research outputs found
A STUDY ON THE ELECTRIC CONDUCTANCE OF RESISTANCE SPOT WELDS - THE CONTACT CONDUCTANCE BETWEEN 2 THIN PLATES
No full textThe authors thank the anonymous reviewer for his constructive comments on the discussion of the results
CHO microRNA engineering is growing up : recent successes and future challenges
No full textmicroRNAs with their ability to regulate complex pathways that control cellular behavior and phenotype have been proposed as potential targets for cell engineering in the context of optimization of biopharmaceutical production cell lines, specifically of Chinese Hamster Ovary cells. However, until recently, research was limited by a lack of genomic sequence information on this industrially important cell line. With the publication of the genomic sequence and other relevant data sets for CHO cells since 2011, the doors have been opened for an improved understanding of CHO cell physiology and for the development of the necessary tools for novel engineering strategies. In the present review we discuss both knowledge on the regulatory mechanisms of microRNAs obtained from other biological models and proof of concepts already performed on CHO cells, thus providing an outlook of potential applications of microRNA engineering in production cell lines
Power-efficient gate control of synchronous boost converters with high output voltage
No full textA half output voltage swing gate driving scheme is presented for high voltage single chip DC/DC converters. In the proposed scheme the energy for the PMOS gate drive is reused for the NMOS gate drive, and switching loss is reduced. A high speed and area-efficient high voltage level shifter is also realised. A prototype is implemented using a 0.5 mu m 40 V power BiCMOS process
Spin-orbit density functional theory calculations for (X = F, Cl, Br and I) molecules
No full textTwo component spin-orbit density functional theory (SODFT) calculations for spectroscopic constants of IX (X = F, Cl, Br and I) molecules have been performed with several functionals using shape-consistent relativistic effective core potentials (RECPs) with effective one-electron spin-orbit operator. The SODFT results obtained with the B3LYP functional are in very good accord with the results of previous two-component CCSD(T) calculations with the same RECP and basis sets. Results of two-component SODFT calculations with RECPs are also in good agreement with reported all-electron relativistic DFT calculations with the same functionals. The spectroscopic constants obtained with ACM and PBE0 functionals display the best agreement with the experimental values among the functionals tested. Spin-orbit effects from the SODFT calculations result in increases of bond lengths and decreases of dissociation energies and harmonic vibrational frequencies and the magnitudes are in reasonable agreement with those from two-component CCSD(T) calculations. Spin-orbit effects appear to be quite insensitive to the choice of functionals for the bond lengths and harmonic vibrational frequencies, but those of the dissociation energies somewhat deviate with the differing class of functionals
Correcting image distortion in the X-ray digital tomosynthesis system for PCB solder joint inspection
No full textX-ray digital tomosynthesis (DT), which makes a cross-sectional image of 3D objects, has been researched and implemented in industrial applications nowadays, such as printed circuit board (PCB) inspection and inspection of electronic parts and other industrial parts/products. In this method, a cross-section image is obtained from a synthesis of more than two images projected from different views. However, distortion in X-ray images in practical imaging situation breaks the correspondences between those images and prevents us from acquiring accurate cross-section images. In this research, we propose a series of image correction method, which is composed of a neural network-based feature extraction for the distorted image and building a polynomial mapping function. The distorted raw image is sequentially corrected in terms of shape and intensity by using a reference pattern. To avoid corruption in feature extraction for the distorted image, an edge-filtered image is utilized rather than using a binarized one. Kohonen neural network is then employed to automatically group the edge points and localize the features, the pattern centers, without any pre-knowledge about the characteristics of the distortion. The proposed correction method is implemented to an actual DT system by carrying out a series of experiments on PCB. The results reveal the validity of the proposed image correction method and also verify the usefulness of the developed system for application of solder joint inspection. (C) 2003 Elsevier B.V. All rights reserved
Voltage-clamped class-E inverter with harmonic tuning, network for magnetron drive
No full textA passive lossless snubber utilizing harmonic resonance is proposed for the voltage-driven class-E inverter. This snubber reduces the peak resonant voltage stress across the switch in class-E operation by adding the third-order harmonic current into the fundamental resonant part and can be extended to a higher-order network for further reduction. Though the principle is actually equivalent to the class-F operation in RF power amplifiers, it is first tried for the class-E inverter without a current source inductor. A series of analyses is performed to find component values that provide the optimum harmonic condition, and the experimental results from the inverter power supply for driving a magnetron are presented
Dual-band internal WLAN antenna for 2.4/5 GHz laptop PC applications
No full textThis paper presents a dual-band internal WLAN PIFA for 2.4/5 GHz laptop applications in consideration of the influences of laptop housing and LCD. The prototype antenna is modified when installed along the perimeter of the display panel of the laptop housing. The proposed antenna has a small ground plane and achieves an impedance bandwidth of 250 MHz (2.37-2.62 GHz) in Bluetooth band and 950 MHz (4.98-5.93 GHz) near 5 GHz in WLAN band within 2:1 voltage standing wave ratio (VSWR). It also shows good antenna gain with small volume. These features make it an alternative for use in dual-band WLAN antennas. Design details for the proposed antenna in the case of the antenna itself and the application of laptop PC housing are described, and experimental results of the antenna achievements are investigated and discussed. (c) 2006 Wiley Periodicals, Inc
Crystal structure of the human GINS complex
No full textThe GINS complex mediates the assembly of the MCM2-7 (minichromosome maintenance) complex with proteins in a replisome progression complex. The eukaryotic GINS complex is composed of Sld5, Psf1, Psf2, and Psf3, which must be assembled for cell proliferation. We determined the crystal structure of the human GINS complex: GINS forms an elliptical shape with a small central channel. The structures of Sld5 and Psf2 resemble those of Psf1 and Psf3, respectively. In addition, the N-terminal and C-terminal domains of Sld5/ Psf1 are permuted in Psf2/ Psf3, which suggests that the four proteins have evolved from a common ancestor. Using a structure- based mutational analysis, we identified the functionally critical surface regions of the GINS complex.X113935sciescopu
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