Upgrade of the beam profile ionization monitor for the KOMBAS fragment separator

The results from upgrade of an ionization beam profile monitor (IBPM) are presented. The IBPM consists of a conventional capacitor that extracts the ionization products of the residual gas and analyzing capacitors. The main objective of this upgrade was to create a device with uniform spatial resolution. For this purpose, an additional difference of potentials, the ramping of which allows the beam cross section to be scanned, is applied between the capacitors of the monitor, while the electric fields in the capacitors themselves remain constant. Two IBPMs have been developed as a result of the facilitys upgrade: an IBPM for on-line monitoring of the vertical and horizontal beam current distributions in the beam line in an area of 8 × 8 cm² with a uniform 1-mm resolution, and an IBMP for detailed beam profile monitoring with a uniform resolution of 1 × 1 mm² over the scanning region. It was established experimentally that the proposed scanning technique provides good results in beam profile measurements when the ion component of the ionized residual gas is extracted; for the electron component, the result is much worse.__________Translated from Pribory i Tekhnika Eksperimenta, No. 2, 2005, pp. 61–66.Original Russian Text Copyright © 2005 by Teterev, Phi Thanh Huong.     

DYP-40薄膜电容切片机中润滑膜进给机构的设计

薄膜电容器由于具有很多优良的特性,因此是一种性能优秀的电容器。薄膜电容器主要应用于电子、家电、通讯、电力、电气化铁路、混合动力汽车、风力发电、太阳能发电等多个行业,这些行业的稳定发展,推动了薄膜电容器市场的增长.随着技术水平的发展,电子、家电、通讯等多个行业更新换代周期越来越短,而薄膜电容器凭借其良好的电工性能和高可靠性,成为推动上述行业更新换代不可或缺的电子元件。主要介绍了凸轮拉杆机构中的润滑膜进给机构的设计及应用机构。     

Fast energy output from a high-current pulsed capacitor by using a pseudospark gap

Results of works on a fast energy output from a capacitor by using a pseudospark gap are described. For this purpose, an HCEIcap 50-0.1 capacitor was specially designed with a combined paper-film insulation impregnated with a castor oil with three types of films: mylar, polypropylene, and teflon. A TDI1-50K/50 pseudospark gap was modified so that the total circuit inductance did not exceed 10 nH. During tests at 40–45 kV, current pulses of ～100 kA with a 2.4 × 10¹²-A/s rise rate were obtained.     

A megavolt frequency generator pulses with an FWHM duration of 30 ns

A generator of a pulse voltage with an amplitude of up to 1 MV based on a ten-stage voltage multiplier is described. The generator contains a control panel, a unit for periodical triggering of spark gaps in the generator stages, and a rectifier outputting a voltage of ± 50 kV for charging capacitors in stages. The generator has an output discharge capacitance of 500 pF, a stored energy of 250 J, a self-inductance of <0.7 μH, a guaranteed service life of 10⁵ charging-discharging cycles, a rise time of the first voltage half-wave of 15 ns at a load of 200 pF, and a repetition rate of 1 Hz. To reduce the self-inductance of the source, insulating housings of capacitors and spark gaps are used in its layout.     

A High-Current Pulse Generator SIGNAL with an Inductive Energy Storage and a Microsecond Plasma Opening Switch

The primary energy storage in the SIGNAL installation is a 4.7-F capacitor bank with a stored energy of up to 24 kJ switched by a gas-discharge gap switch of the trigatron type. The plasma source and the design of the microsecond plasma opening switch ensure current flow through this switch and inductive storage for a time of up to 1.7 s. The current amplitude reaches 330 kA. The current switched to the load is 20–300 kA in various modes with a rise time of 10–200 ns. The voltage across the feedthrough insulator reaches 400 kV. The installation is used in experimental studies of linear pinches, capillary discharge, and microsecond plasma opening switches.     

Embedded components in printed circuit boards: a processing technology review

It is evident that embedded passive components (EPCs) allow packaging substrate miniaturization and have the potential to reduce costs. Moreover, they exhibit superior electrical behaviour with respect to the minimization of parasitic effects. However, as for most emerging technologies, there is no well-established process or method for EPCs that lead to the desired result, but many have been and are still being investigated. This article attempts to review the state of the art of resistor and capacitor EPCs, including an assessment of the pros and cons of the various technologies pursued.In the review, it is found that compared to discrete surface mount devices, EPCs provide (in order of current importance): space reduction of 30% or more, better HF signal integrity and potential cost reduction. Embedded resistors in thin-film technology are, in general, restricted to small resistance values up to a few k. Embedded resistors in ceramic thick-film technology require a high temperature curing process and much care during lamination, but they can be combined with embedded capacitors and exhibit high stability. Whereas embedded resistors in polymer thick-film technology require a low curing temperature and can be combined with capacitors, they exhibit poorer electrical properties and stability. Moreover, tolerances of embedded resistors after manufacturing are exceeded by 15%, independent of the manufacturing technology, which means that laser trimming is required.Embedded capacitors are based mostly on barium-titanite with a dielectric constant of only approximately 20, which limits the capacitance density to a few nF/in². Ferroelectric material with a dielectric constant up to 2000 for embedded capacitors has been investigated but not yet established. Besides the traditional screen print technology for the deposition of pastes and inks, the ink-jet technology becomes more promising. Much higher flexibility with respect to material composition, layer thickness and even active components like LEDs have already been produced by ink-jetting.     

Highly sensitive,precise, and traceable measurement of force

Force in the micronewton range may be traced to the International System of Units by an electrostatic force balance weight system. However, there is a conflict between range and sensitivity. To solve this problem, a lever-type force metrology system based on the null-balance method is reported. The force is loaded on one end of the lever, causing elastic torsion of the central rod, and an electrostatic force is applied to the other end. With a variety of mass loading positions and standard weights, a wide range of moments may be produced to calibrate the system. The electrostatic force was generated by a pair of coaxial cylindrical capacitors where the applied voltage was converted into electrode displacement. The design of the inner and outer cylindrical capacitors was deduced considering the material and miniaturization requirements, and concentric alignment was ensured by a vision system. The null balance was achieved by a proportion-integration-differentiation control system, so that the external force was compensated by the electrostatic force. A method to increase the center of gravity was used to improve the resolution. The mechanism was analyzed based on stiffness, strength, stability, and frequency. Furthermore, the impact on the capacitance gradient due to the capacitor tilt caused by the applied force was estimated. Standard weights were utilized to evaluate the system performance. The results showed that a stiffness of 0.8 N/m and a force resolution of 10^?8 N were achieved.     

The effect of the composition of a Nd-loaded liquid organic scintillator on light yield

The light yield in samples of a Nd-loaded scintillator was measured. The scintillator composition differed in the solvent (pseudocumene (PC) and a mixture of PC with linear alkyl benzene), the scintillating dye type (РРО or ВРО), and the Nd concentration. The light yield in the PC (PPO, 1.5 g/L), which was approximately 11500 photons/MeV, was assumed to be the standard. The ionizing-radiation sources were ¹³⁷Cs, ²⁴¹Am, and ¹⁰⁹Cd radionuclides. It was shown that the light yield in the scintillator with a Nd concentration as high 30 g/L (~3%) in PC made it possible to attain energy resolution at a level of 3% at an energy of 3 MeV (neutrinoless 2β decay of ¹⁵⁰Nd).     

A prototyping and microfabrication CAD/CAM tool for the excimer laser micromachining process

A CAD/CAM tool for prototyping and small-scale production of micro-electro-mechanical systems (MEMS) devices based on the excimer laser ablation process has been developed. The system’s algorithms use the 3D geometry of a microstructure, defined as an STL file exported from a CAD model, and parameters that influence the process (laser fluence, pulse repetition frequency, number of shots per area, wall angle, stitching errors) to automatically generate a precise NC part program for the excimer laser machine. The performance of the system has been verified by NC part program generation for several 3D microstructures and subsequent machining trials. An initial stitching error of 23.4±2.2-μm wide and 3.4±1.5-μm high was observed when the overlap size between adjacent volumes was zero, when ablating 100×100-μm features in polycarbonate (PC) at a fluence of 0.5 J/cm² using a workpiece-dragging technique. When the size of the overlap was optimised by a system based on optimal process parameters determined by the Taguchi design of experiment method (DOE), and incorporated in the mask design, the maximum stitching error was reduced to 13.4±2.2-μm wide and 1.4±0.9-μm high under the same conditions. By employing a hexagonal-shaped mask with incorporated size of the image overlap, reduced horizontal-stitching errors of 2.4±0.2-μm wide and 1.4±0.2-μm high were observed. The system simplifies part program creation and is useful for excimer laser operators who currently use a tedious trial and error process to create programs and complex masks to generate microstructure parts.     

Small-capacity deadweight force standard machine compensating loading frame

The Korea Research Institute of Standards and Science (KRISS) has developed a 20 N deadweight force standard machine. The machine consists of a weight stack, a loading frame, a taring system, a main body and a control system. The taring system has the role of compensating the initial force generated by the loading frame. With two motors, a displacement sensor, several limit switches, and a synthetic control system consisting of a programmable logic controller and an operating PC, the machine can be operated almost fully automatically. The machine can generate a compressive force in the range of 0.5–22 N with a relative expanded uncertainty of 1.0 × 10^–4. The machine was compared with a 200 N deadweight force standard machine. In the comparison, the relative deviation was 5.8 × 10^–5, less than the declared expanded uncertainty of the force standard machines, therefore confirming the machine’s accuracy.     

A layered microchip conductance detector with through-layer access to detection fields and high sensitivity to dielectric constant

The present study explores a novel apertured microchip conductance detector (AMCD) that is sensitive to dielectric constant. Fashioned on silicon oxide/silicon using optical microlithography, the detector has novel parallel-plate geometry with a top mesh electrode, a middle apertured insulator, and a bottom conducting electrode. This monolithic apertured architecture is planar and may be provided with a thin insulator layer enabling large capacitances, while the top mesh electrode and middle apertured-insulator enable access to regions of the capacitor where electric fields are strong. Hence, the detector is sensitive yet mechanically robust. To test its response, the AMCD was immersed in various solvents, namely water, methanol, acetonitrile, and hexanes. Its response was found to vary in proportion to the solvents' respective dielectric constants. The AMCD was also able to distinguish quantitatively the presence of various molecules in solution, including molecules with chromophores [such as acetylsalicylic acid (ASA)] in methanol and those without chrompohores [such as polyethylene glycol 200 Daltons (PEG200)] in methanol or water. The universal nature of dielectric constant and the microchip detector's sensitivity point to a wide range of potential applications.     

A magnetic-thyristor pulse generator for electric-discharge technologies

A generator is described that is intended for operation in the area of electric-discharge technologies. Depending on the electrical strength of the load, the generator produces voltages of up to 50 kV, the dissipated energy of the pulse is up to 200 J, and the pulse repetition rate is up to 100 Hz. The generator is based on the direct discharge of capacitors to a discharge gap through a coaxial cable with a length of up to 200 m and without additional switching components. The circuit stabilizing the pulse energy due to recuperation of the unused energy in the filter capacitor of the power supply is used to stabilize the energy dissipated by the load.     

Dilute Triton X-100 in water as a reference liquid for hydrometer calibration using Cuckow’s method

We propose a 200 parts in 10⁶ by volume solution of the surfactant Triton X-100 in water as a reference liquid for hydrometer calibration using Cuckow’s method. This liquid has advantages over traditional hydrocarbon fluids such as nonane and tridecane; it is safer, less expensive, and the density can be determined with sufficient accuracy from the mixing ratio. Previous researchers have used about 70 parts in 10⁶ by volume Triton X-100 in water. Here we report measurements on the surface tension behaviour of aqueous Triton X-100 solutions with concentrations in the range (39–301) parts in 10⁶ by volume. These measurements indicate that a 200 parts in 10⁶ mixture is a suitable compromise between surface tension behaviour and accuracy of calculation of the liquid density from the mixing ratio of Triton X-100 to water. Performance tests to confirm the suitability of this liquid are given.     

Investigating on performance parameters and flow field of centrifugal compressor based on the splitter blade leading edge’s location effect

Impeller design in turbomachines is one of the most challenging issues in these machines’ systems, which still plays a significant role in their efficiency and performance. This article considers different designs for splitter blades. Therefore, the CFD methods modify the position of the splitter blades leading edge at the hub and shroud. This modification shall lead to a different splitter blade profile from the main blades. Then, the effects of splitter blades are discussed, and the performance parameters have also been studied to improve this method’s implementation. The results revealed that the compressor’s efficiency was improved by approximately 1.5 % in one specific case. This finding proves that the previous design methods were not the optimum ones for compressors and how to increase the compressor’s efficiency by CFD methods and by changing the splitter blades’ location.

     

由正交傅里叶-梅林矩定位的双光纤耦合微内尺度测量

为了解决微内尺度的精密测量问题,提出了一种基于正交傅里叶-梅林矩(OFMM’s)定位的双光纤耦合瞄准触发式微内尺度测量方法。该方法通过耦合器实现光能量在不同光纤间的反向传输,把双光纤传感器测头的横向位移量转化为光束的偏转量,通过显微成像系统把此偏转量转化为CCD图像捕捉系统更大的横向位移量。为提高测量精度,运用OFMM’s的幅值旋转不变性和独特的图像形状细节特征的描述能力对CCD图像捕捉系统的图像信号进行亚像素定位;根据OFMM’s的实际位置进行补偿以提高输出图像边缘的定位精度,从而提高测量精度。对OFMM’s的定位精度及传感器性能进行了实验验证,并依据JJF(黑)8-2008,利用自行研制的微小孔径测量机实现了对直径为200μm、深2 000μm深盲孔的直径测量,其测量重复性不确定度优于0.25μm。     

Capacitor units with air insulation for linear transformers

The design of two capacitor units intended for use in high-power pulsed generators is described and the results of their tests are presented. Each unit is an assembly consisting of a multichannel spark gap and two capacitors with a total capacitance of 80 or 16 nF and a charging voltage of up to 100 kV. The use of air at atmospheric pressure as the insulating and working medium of the spark gap is a feature of the capacitor units. The following parameters of the output pulses were obtained at a resistive load for the 80- and 16-nF units: currents of ～48 and ～20 kA, voltages of ～55 and ～52 kV, and times of energy deposition into the load of ～140 and ～60 ns, respectively. A model for numerical calculation of the transient discharge process in the capacitor units is presented and the influence of the capacitance of the capacitors and the number of spark channels in the spark gap on the parameters of the generated pulse is analyzed.     

Analyzing the shape parameter effects on the performance of the mixed-flow fan using CFD &amp; Factorial design

Fans are representative turbo-machinery widely used for ventilation throughout the industrial world. Recently, as the importance of energy saving has been magnified with the fans, the demand for the fans with high efficiency and performance has been increasing. The representative method for enhancing the performance includes design optimization; in practice, fan performance can be improved by changing the shape parameters such as those of meridional plane, impeller, and diffuser. Before optimizing the efficient design, a process of screening to select important design parameters is essential. The present study aimed to analyze the effects of mixed-flow fans’ shape parameters on fan performance (static pressure and fan static efficiency) and derive optimum models based on the results. In this study, the shape parameters considered in the impeller domain are as follows: tip clearance, number of blades, beta angle of Leading edge (LE) in the blade, and beta angle of Trailing edge (TE) in the blade. The shape parameters considered in the diffuser domain are as follows: meridional length of the Guide vane (GV), number of GV, beta angle of LE in the GV and beta angle of TE in the GV. The effects of individual shape parameters were analyzed using the CFD (Computational fluid dynamic) and DOE (Design of experiments) methods. The reliability of CFD was verified through the comparison between preliminary fan model’s experiment results and CFD results, and screening processes were implemented through 2^4-1 fractional factorial design. From the analysis of DOE results, it could be seen that the tip clearance and the number of blades in the impeller domain greatly affected the fan performance, and the beta angle of TE at the GV in the diffuser domain greatly affected the fan performance. Finally, the optimum models with improved fan performance were created using linear regression equations derived from 2^4-1 fractional factorial design.     

A method for rejecting unreliable ceramic capacitor blanks

The possibility of assessing the degree of baking of ceramic capacitor blanks according to changes in their electrophysical properties (tan δ and E _br) after moistening is considered. The method of vacuum moistening involving measurements of dielectric losses or the electric strength is proposed for nondestructive random (at the baking stage) or total (at the stage of burning-in of Mo-Mn electrodes) testing of blanks for capacitors. This method allows rejection of up to 25–30% of unreliable capacitor blanks.     

高压串联电容器不平衡保护的研究

高压串联电容器主要有H形接线和分支接线两种接线形式,分别针对这两种接线形式的电容器,定量推导了单个支路电容器故障时不平衡电流与总电流的比值和过电压倍数,在此基础上,对这两种接线形式的电容器不平衡保护的动作特性进行了分析。