Development of an Experimental EUVL System

The authors have developed an experimental system for the studies of extreme ultraviolet projection lithography at 13.0nm wavelength, which includes a laser plasma source,an ellipsoidal condenser, a transmission mask and a Schwarzschild optics. The optical system is optimized to achieve 0.1μm resolution over a 0.1mm diameter image field of view and the mirrors of the objective were coated with Mo/Si multilayer to provide 60% reflectance atnear-normal incidence angle for 13.0nm radiation.     

Characteristics of a symmetrical Cockcroft-Walton power supply of 50 Hz 1.2 MV∕50 mA

A 1.2 MV∕50 mA symmetrical Cockcroft-Walton (SCW) power supply of over 83% power efficiency, driven by 50 Hz frequency, was developed for an industrial electron beam irradiator. It is constructed by capacitors of 45 nF and 28.13 nF in the coupling column and capacitors of 18.75 nF in the smoothing column. Working status of the rectifier in high power output condition was analyzed, and the conduction angle of the rectifier was calculated. The power factor (PF) of the SCW circuit has been studied, and the equivalent condensance of the circuit has been derived. Measurements were done for the PF compensation. The surge impact during the short circuit transient process was considered in choosing the protection resistance. Test results showed that design specifications of the power supply were achieved, with the non-load voltage being up to 1.32 MV and the ratio of ripple voltage to output voltage as 9.4%.     

Analysis of melt-through process of 1.07 μm continuous wave high power laser irradiation on metal

Laser-metal interactions are influenced by various parameters, including laser wavelength and laser pulse duration. By proper adjustments of these parameters, one can create states that manifest different phenomena during laser ablation. In this work, we study laser melt-through of metal using 1 kW high power continuous laser with 1.07 μm wave length. A Ytterbium (Yb) doped fiber laser is used on the metal sample of varying thicknesses (0.1 ～ 2 mm). In addition to providing measurements from the melt-through process, numerical study of thermal transport effect of laser heating and thermo-elastic response of metal are reported. The test-based simulation is shown to reproduce the thermal transport characteristics of beam-metal interaction at high power continuous wave irradiation with notable accuracy.     

Nonlinear control of voltage source converters in AC–DC power system

This paper presents the design of a robust nonlinear controller for a parallel AC–DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC–DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations.     

A study on the variation of the performance and the cost of power generation in a combined heat and power plant with the change of the user facility’s return temperature

Journal of Mechanical Science and Technology - A combined heat and power (CHP) system generates electricity from thermal energy and generates heat by utilizing the remaining thermal energy. The...     

Investigations of the nitrided subsurface layers of an Fe–Cr-model alloy

An Fe–5 wt%Cr alloy was nitrided in gaseous atmosphere at 590 °C for 12 h. In the resulting diffusion layer, nitrides precipitate on a nanometre scale. The microstructure in the diffusion layer was characterised by optical microscopy and hardness measurements. The morphology, volume fraction and chemical composition of the nitrides were determined by means of atom probe tomography. The orientation of the nitrides with respect to the matrix was investigated using three-dimensional field ion tomography. The evolution of the nitrides was studied at different depths from the surface and their nanoscopic features were correlated with the obtained hardness profile. At a depth of 270 μm from the surface, the first stages of nitride formation could be analysed.     

Ester Oxidation—The Effect of an Iron Surface

Carboxy ester oxidation on a low-carbon steel (iron) surface was studied at temperatures of 448 to 523 K to determine the extent of surface reaction between iron and oxidation products. The reaction was followed by semiquantitative analysis of dissolved iron using atomic absorption spectroscopy and by measuring the amount and molecular weight of the polymeric oxidation products using gel permeation chromatography. In contrast to reaction at an aluminum surface, reaction at the iron surface appeared to affect the molecular weight distribution of oxidation polymer and produced soluble iron products that homogeneously catalyzed ester degradation. The formation of soluble iron products was found to be extremely temperature-dependent, related to the degree of oxidation, and almost totally suppressed by a known metal coater—tricresyl phosphate (TCP). Evidence of a similar chemical reaction between carboxy ester oxidation products and an iron surface in the contact zone of an ester-lubricated, four-ball wear test is discussed.     

Novel approach to harmonic control for Class F power amplifier with high power added efficiency

This paper presents a new topology to implement Class F power amplifier for eliminating the on -resistance （ RON ） effect. The time-domain and frequency-domain voltage and current waveforms for Class F amplifier are analyzed using Fourier series analysis method. Considering the on-resistance effect, the formulas of the efficiency, output power, dc power dissipation, and fundamental load impedance are given from ideal current and voltage waveforms. For experimental verification, we designed and implemented a Class F power amplifier, which operates at 850 MHz using AlGaAs/GaAs Heterostructure FET （HFET） device, and analyzed the measurement results. Test results show that the maximum PAE of 67% can be achieved at 28 dBm output power level.     

Synergy Between Corrosion and Wear of Electrodeposited Ni–W Coating

In this study, a block-on-ring wear tester was employed to investigate the tribocorrosion behavior of the electrodeposited Ni–W coating. Columnar grains embedded with lamellar and nanocrystalline microstructure were found in the fabricated Ni–W coating. The passivation of the Ni–W alloy was observed in the potentiodynamic polarization curve measured in 5 wt% NaCl solution. The result showed that with the raise of the applied overpotential, both the wear rate and the surface W-content of the coating increased. On the contrary, the accompanying coefficient of friction decreased with the potential. Small pitting and cracking occurred on the tested specimen. This microcracking structure was also observed in the corroded zone of the Ni–W coating by using TEM microscopy. A further XPS analysis determined the corrosion film was composed of Ni(OH)₂, NiO, and WO₃ on the corroded surface. The formation of this porous corrosion film at high overpotential was found to cause an accelerated weight loss and thereby, the interaction between wear and corrosion, of the Ni–W coating under tribocorrosion.     

Accelerator of the НГ-12И neutron generator as an implanter of hydrogen ions

The use of an updated accelerator of the -12 neutron generator as a high-current implanter of hydrogen ions (protons and deuterons) with energies of 175–210 MeV into wafers made of crystalline silicon is described. The ion-beam scanning system used ensured nonuniformity in the irradiation of wafers with a diameter of 100 mm of <10%, which allowed the production of silicon-on-insulator wafers by the hydrogen splitting technique. The required particle fluence was 10¹⁷ cm^–2. A slight refinement of the setup allows wafers with diameters of up to 200 mm to be irradiated. The design features of the setup as they apply to different temperature conditions (down to a temperature close to that of liquid nitrogen) of the irradiation of 100-mm-diameter wafers are described.Translated from Pribory i Tekhnika Eksperimenta, No. 1, 2005, pp. 126–129.Original Russian Text Copyright © 2004 by Stepovik, Mokichev, Magda, Kiryushkin, Kozikov, Semkov, Kurochkin, Lukin, Khmelnitskii, Popov.     

Nondestructive testing of the state of a ship’s hull with an underwater robot

The possibility of nondestructive testing of a ship’s hull with the AURORA underwater robot is discussed. The robot performs underwater cleaning of a ship’s hull with simultaneous contactless measuring of the thickness of the hull sheet with an ultrasonic detector; it tests the state of the protective coating and restores the shape of the underwater part of the hull.     

高速钢W18和W6的正确鉴别

高速钢是一个量大面广的钢种,一般用于刀具制造的有W18Cr4V和W6Mo5Cr4V2(简称W18、W6)两种牌号。在生产中,由于管理上的原因,W18和W6混料现象时有发生,而这两种高速钢的淬火温度是不相同的,任何一次混料都会带来严重的经济损失,如何将混料的W18和W6区别开来,有以下几种方法。     

MEMS器件的W2W真空封装研究

开发了一种适于MEMS器件的基于W2W(圆片对圆片)工艺的简易的圆片级真空封装方法。通过电镀工艺在MEMS器件圆片和封盖圆片上各沉积含5μm Cu和1.5μm Sn金属层的键合环。器件圆片和封盖圆片在160℃及0.01Pa的真空环境中保持10 min以形成真空,之后在270℃及4 MPa保持30 min通过Cu和Sn的互溶扩散工艺完成键合。测量键合区内Cu元素和Sn元素的重量比,证实形成了Cu3Sn和Cu6Sn5金属间化合物。通过剪切力测试对单个芯片的键合面强度进行标定,计算剪切强度达32.20 MPa。     

Force spectroscopy of an elastic peptide: effect of D₂O and temperature on persistence length

This study explores the mechanical unfolding of elastic protein analogues as a function of temperature, in both H₂O and D₂O, using atomic force microscopy (AFM) force spectroscopy in a specially constructed AFM liquid cell. This represents the first time that the effect of D₂O on protein flexibility has been investigated at the single molecule level by this technique. Model elastic peptides, R6, were encoded from synthetic genes expressed in Escherichia coli. The peptides possess short N‐ and C‐terminal domains with central repetitive domains containing 13 repeats of the motif PGQGQQ‐plus‐GYYPTSLQQ. These sequences mimic those in native high molecular weight subunit glutenin proteins which confer elasticity to bread dough. Fitting single molecule stretching events to the worm‐like chain model, allows determination of the molecular persistence length under various experimental conditions. The effect of increasing the temperature is to increase the persistence length of the peptide in both H₂O and D₂O, consistent with the expected “thermal softening” effect. However, the effect is significantly enhanced in D₂O, in which the persistence length at 45°C is ～25% greater than the value measured in H₂O at the same temperature. Stronger intrapeptide H‐bonding due to isotopic substitution of hydrogen for deuterium is the most likely cause of the enhanced backbone rigidity. Microsc. Res. Tech. 74:170–176, 2011. © 2010 Wiley‐Liss, Inc.     

Elastic–plastic contact analysis of an ellipsoid and a rigid flat

The work presents a finite element model (FEM) of the equivalent von-Mises stress and displacements that are formed for the different ellipticity contact of an ellipsoid with a rigid flat. The material is modeled as elastic perfectly plastic and follows the von-Mises yield criterion. The smaller the ellipticity of the ellipsoid is, the larger the depth of the first yield point from the ellipsoid tip happens. The FEM produces contours for the normalized normal and radial displacement as functions of the different interference depths. The evolution of plastic region in the asperity tip for a sphere (k_e=1) and an ellipsoid with different ellipticities $(k_e=\frac{1}{2}\mathrm{and}\frac{1}{5})$ is shown with increasing interferences. It is interesting to note the behavior of the evolution of the plastic region in the ellipsoid tip for different ellipticities, k_e, is different. The developments of the plastic region on the contact surface are shown in more details in Fig. 7. When the dimensionless contact pressure is up to 2.5, the uniform contact pressure distribution is almost prevailing in the entire contact area. It can be observed clearly that the normalized contact pressure ascends slowly from the center to the edge of the contact area for a sphere (k_e=1), almost has uniform distribution prevailing the entire contact area for an ellipsoid $(k_e=\frac{1}{2})$, and descends slowly from the center to the edge of the contact area for an ellipsoid $(k_e=\frac{1}{5})$.