1,123 research outputs found
A HIGH-SPEED SI BIPOLAR-TRANSISTOR WITH SAVEN - (SELF-ALIGNED DEVICE USING VERTICAL NITRIDE)
No full textThis paper presents a new device called SAVEN (self-aligned device using vertical nitride) which has faster switching speed characteristics. To obtain this level of performance, SAVEN adapts the technology reducing the extrinsic base region by controlling the vertical nitride layer. Also, it uses the trench isolation and TiSi2 process of the n+ polysilicon emitter region. The emitter area is designed to be 1.0 x 4.0 mum2. DC characteristics of the fabricated transistor is evaluated and analyzed for the SPICE input parameters. The current gain of the butted npn transistor is around 100, and the breakdown voltage for the collector-to-emitter is 7.5 V. The junction capacitances of base-to-collector and collector-to-substrate are measured at 12 fF and 19 fF, respectively. These low values are due to the small extrinsic base width and elimination of the parasitic capacitance between the epitaxial layer and substrate. From the measurement of the current mode logic (CML) ring oscillator with 31 stages, the minimum propagation delay time per gate is 45 ps at 1.4 mW.The authors are grateful to S.H.Chai, J.G.Koo and J.H.Lee for many helpful discussions. Also they would like to thank Korea Telecommunication (KT) for financial support
Thermodynamic design data and performance evaluation of the water plus lithium bromide plus lithium iodide plus lithium nitrate plus lithium chloride system for absorption chiller
No full textDuhring (P-T-X) and enthalpy-concentration (H-X-T) diagrams of the H2O + LiBr + LINO3 + LiI + LiCl (mole ratio of LiBr : LiNO3 : LiI :LiCl = 5: 1 : 1 :2) system were constructed by using the experimental data sets. Thermodynamic design data for a double-effect series-flow absorption chiller were calculated at various operating conditions [2 less than or equal to T(e)less than or equal to 14 degrees C, 30 less than or equal to T(a)less than or equal to 50 degrees C, 30 less than or equal to T(c)less than or equal to 50 degrees C, T-gh(COP = 0) less than or equal to T-gh less than or equal to T-gh (crystallization limit)] by a computer simulation. The proposed working fluid was found to be applicable to cycle operation of air-cooled absorption chiller with no crystallization problem at higher absorber temperature. (C) 2000 Elsevier Science Ltd. All rights reserved
Cyano-bridged homometallic 1-d and bimetallic 2-d assemblies: Synthesis, structures, and magnetic properties of [Ni(baepn)(CN)](n)(ClO(4))(n) and [Ni(baepn)](2n)[Fe(CN)(6)](n)(H(2)O)(8n)
No full textCyano-bridged homometallic complex [Ni(baepn)(CN)](n)(ClO4)(n) (1) and bimetallic complex [Ni(baepn)](2n)[Fe(CN)(6)](n)-(H2O)(8n) (2) [baepn = N,N'-bis(2-aminoethyl)-1,3-propanediamine] were synthesized and characterized. 1 crystallizes in the monoclinic space group P2(1)/n with a = 9.560(3) Angstrom, b = 10.700(3) Angstrom, c = 14.138(9) Angstrom, beta = 90.18(6)degrees, and Z = 4; 2 crystallizes in the monoclinic space group P2(1)/c with a = 8.951(2) Angstrom, b = 13.672(3) Angstrom, c = 14.392(3) Angstrom, beta = 98.906(4)degrees, and Z = 4. The complex 1 has one-dimensional structure whose chain vector runs along the b axis with baepn ligands and perchlorate anions alternately arranged up and down in the c direction. The antiferromagnetic nature of 1 was explained in terms of the infinite chain model and Haldane gap, giving g = 2.33, J = -29.4 cm(-1), and the magnitude of Haldane gap E-g = 5.22 K. The complex 2 that constitutes the first example of 2-D bimetallic assembly of Ni(II) ion and ferrocyanide anion is composed of the neutral layers based on the [Ni4Fe4] square grid spanning in the bc plane. For 2, the analysis with the Curie-Weiss law in 2-300 K range results in Theta = 0.200 K and the magnetism was explained in terms of the ability of ferrocyanide in the -Ni-NC-Fe-CN-Ni unit to promote ferromagnetic Ni-Ni interaction.The financial supports from the Korea
Science and Engineering Foundation (CMDS, Grants R02-
2001-000-00016-0 and R02-2002-000-00057-0) and the
BK21 project are gratefully acknowledged
Effects of the resistivity and crystal orientation of the silicon PIN detector on the dark current and radiation response characteristics
No full textPresident Hyun-Sik Chae of SF Technology Co.
Ltd. for assembling our detectors with amplifier circuit
Analysis of protein phosphorylation in fertilized eggs of Rana dybowskii
No full textThe phosphorylation of 100 and 170 kDa proteins was increased in response to fertilization in eggs of Rana dybowskii. There was a transient increase of inositol 1,4,5-trisphosphate and diacylglycerol in fertilized eggs. Treatment of 0.2 mM CaCl2 in unfertilized egg homogenate also phosphorylated the 100 and 170 kDa proteins. Data suggest that the sperm signal increases IP3 content in egg cytoplasm, triggering Ca2+ release from internal storage into cell matrix to activate Ca2+-dependent protein kinases, necessary for the early embryonic development
Chemical modification of carbon nanotubes and preparation of polystyrene/carbon nanotubes composites
No full textSingle-walled carbon nanotubes (SWNTs) have been chemically modified through the formation of carboxylic acid functionalities or by grafting octadecylamine and polystyrene onto them. We purified SWNTs with nitric acid to remove some remaining catalysts and amorphous carbon materials. After purification, we broke the carbon nanotubes and shortened their lengths by using a 3:1 mixture of concentrated sulfuric acid and nitric acid. During these purification and Cutting processes, carboxylic acid units formed at the open ends of the SWNTs. Octadecylamine and amino-terminated polystyrene were grafted onto the cut SWNTs by condensation reactions between the amine and carboxylic acid units. The Cut SWNTs did not disperse in organic solvents, but the octadecylamine-grafted and polystyrene-grafted SWNTs dispersed well in dichloromethane and aromatic solvents (e.g., benzene, toluene). Composites were prepared by mixing polystyrene with the octadecylamine-grafted or poly styrene-grafted SWNTs. Each composite had a higher dynamic storage modulus than that of a pristine polystyrene. The composites exhibited enhanced storage moduli, complex viscosities, and unusual non-terminal behavior when compared with a monodisperse polystyrene matrix because of the good dispersion of carbon nanotubes in the polystyrene matrix.Authors would like to express the sincere thanks to KOSEF (Korea Science and Engineering
Foundation), CAFPoly (Center for Advanced Functional
Polymers), and BK 21 program for their financial support
Crystallization and preliminary X-ray crystallographic analysis of malonamidase E2, an amidase signature family member
No full textMalonamidase E2 from Bradyrhizobium japonicum catalyzes the hydrolysis of malonamate. The enzyme belongs to an amidase signature family which has a highly conserved serine- and glycine-rich sequence over a stretch of similar to45 amino acids. More than 100 known or predicted members belonging to this family, whose biological functions vary widely, can be identified in sequence databases. Although urgently needed, no three-dimensional structure of any protein of this family is yet available. The crystallization of malonamidase E2 was undertaken as a first step toward the goal of providing information on the canonical structure of the amidase signature family. The enzyme was crystallized using the hanging-drop vapour-diffusion method at 277 K under two different conditions. One crystal form, which is easier to work with than the other form, belongs to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 104.29, b = 95.58, c = 74.90 Angstrom. The unit cell is likely to contain two molecules of MAE2, with a crystal volume per protein mass (V-M) of 2.045 Angstrom(3) Da(-1) and solvent content of about 39.9% by volume. A native data set to 1.8 Angstrom resolution was obtained from a flash-cooled crystal using synchrotron radiation
Improve the IDM recipe creation flow by integrating and benchmarking a new solver
No full textThe core business of ASML is to develop lithography tools (scanners) for chip manufacturing. As the feature size decreases on the chips, the need to control the performance of ASML scanners is increased therefore this requires more advanced metrology techniques/tools. These advanced metrology tools help to analyze what is actually printed on the wafer with the scanner. YieldStar (YS) is an optical metrology tool developed by ASML. YieldStar is an angle-resolved scatterometer which allows to measure both Optical Critical Dimension (OCD) and Overlay (OV). Since YS uses visible light and the dimensions of the features of interest are generally a few nm, it is difficult to measure these features on wafers in a direct manner. Therefore, it is needed to model the structures/features and use optical modeling and optimization techniques to reconstruct the right profile of the structure. The modelling of the geometrical and material parameters is performed in YS software. Within the YS software, ASML provides their customer a platform to support metrology recipe creation to reconstruct CD (critical dimensions: all the geometrical parameters/features on a chip) based on the measurements performed on YS tool. This metrology recipe creation platform is called In Device Metrology (IDM) Recipe Creation Flow (RCF). The current IDM RCF is comprised of several steps, which together with the complexity of the IDM profile contribute to the total recipe creation time of an IDM profile. The recipe creation time for complex 3D profiles is high because some of the steps in the RCF require long computation time and large manual user interaction. The recipe creation time is needed to be reduced in order to bring the recipe creation flow within specification which can be achieved by automating the IDM recipe creation step(s). Therefore, to automate the IDM RCF, a new solver has been designed. In this work, an improvement in the IDM RCF has been proven by validating the performance of the new solver for different IDM profiles. As a result of this study, it is found that the new solver has fully automated the IDM RCF step(s) and the time to recipe is reduced, while, at the same time it has merged some of the steps together and reduced the number of steps in the IDM RCF. The implementation of the new solver has also increased the application scope of the IDM RCF
Author's reply to comment on ""Biological removal of polychlorinated dibenzo-p-dioxins from incinerator fly ash by sphingomonas wittichii RW1"" by Rolf U. Halden
No full textX111sciescopu
FOURIER TRANSFORM MICROWAVE SPECTROSCOPY OF SCS (X), YS (X) AND VS (X)
No full textAuthor Institution: Department of Chemistry and Steward Observatory, University of Arizona, Tucson, AZ 85721Pure rotational spectra of three transition-metal monosulfides, ScS, YS, and VS, have been recorded using Fourier transform microwave spectroscopy (FTWM) in the range 10-40 GHz. These molecules are all free radicals and have been synthesized in a mixture of HS gas with metal vapor, obtained by laser ablation of a metal rod. In the case of ScS and VS, a discharge was necessary to successfully produce the molecules. For YS, the N=10, 21, 32 and 43 rotational transitions have been recorded. For ScS and VS, the N=10, N=21 and N=32 have been obtained. Vanadium, scandium and yttrium hyperfine structures were resolved for these species. Rotational, fine structure and hyperfine coupling constants have been determined for all three radicals. This works completes the high-resolution pure rotational measurements of 3d transition-metal monosulfides, and provides the most accurate values of the hyperfine parameters for these molecules to date. Bond lengths and spectroscopic parameters will be presented
- …
