Read/write mechanisms and data storage system using atomic force microscopy and MEMS technology

Information storage system that has a potentially ultrahigh storage density based on the principles of atomic force microscopy (AFM) has been developed. Micro-electro-mechanical systems (MEMS) technology plays a major role in integration and miniaturization of the standard AFM. Its potential application for ultrahigh storage density has been demonstrated by AFM with a piezoresponse mode to write and read information bits in ferroelectric Pb(Zr(x)Ti(1 - x))O3 films. With this technique, bits as small as 40 nm in diameter have been achieved, resulting in a data storage density of simply more than 200 Gb/in2. Retention loss phenomenon has also been observed and investigated by AFM in the piezoresponse mode. Finally, local piezoelectric measurements of PZT films by different processing technologies are discussed in detail.     

Air Bearing Simulation for Bit Patterned Media

Patterned media are being considered as a promising approach for achieving storage densities beyond 1 Tb/in² on hard disks. Patterned media reduce cross talk of adjacent bits and improve thermal stability of the media. In this investigation, the flying characteristics of femto-type sliders over bit patterned media (BPM) are investigated. The discrete bits of the disk are modeled as isolated conical protrusions on the disk surface.     

电动汽车充电桩充电管理系统设计

为了提高电动汽车充电桩的兼容性,设计了一套用于电动汽车充电桩的充电管理系统.基于STM32的电动汽车充电桩充电管理系统具有射频卡数据读写、电表数据读写、数据信息存储、PWM波输出和捕获、键盘输入等功能,系统提供了良好的人机界面,能够对充电过程中的相关信息进行获取和管理.     

The detection quantum efficiency of electronic image recording systems

The principles in design and operation of TV electron-image recording systems are elucidated. Using the ‘detection quantum efficiency’ (DQE) as a figure of merit, the influence of various parameters is discussed, such as single electron response, read-out noise and saturation of the camera tubes as well as the properties of digital frame stores. The analogue signal processing mode gives a DQE of about 0·8 and can be adapted to a wide range of operating conditions. Counting of normalized electron signals in digital storages allows an almost ideal image detection, which can, however, at best only be applied with a current density below 10^?13 A cm^?2. Compared to photographic recording, electronic systems offer real-time response, compatibility with computers and great flexibility of stored information. Their DQE is similar in the analogue mode but superior in the counting mode. The storage capacity, on the other hand—particularly the number of pixels—is presently still inferior to the photoplate.     

Tem Of Dislocations Under High Stress In Germanium And Doped Silicon

The stacking fault energies y of silicon (58 ± 6 mJ m^?2) and germanium (75 ± 10 mJ m^?2) were determined. Within the limits of accuracy γ was not found to change on doping with (13·8 mol m^?3 (8 × 10¹⁸ cm^?3) boron, and 1·17 mol m^?3 (7 × 10¹⁷ cm^?3) phosphorus). Freezing in dislocations under high shear stress reveals a different behaviour of screw dislocations: whereas these dislocations become wider in pure and p-silicon, they become narrower in n-silicon. From this we conclude the ratio of mobilities of the two 30° partials to be different in n- and p-silicon. Other observations on frozen dislocations are mentioned.     

水产品可追溯信息管理系统的设计

以SQLServer2005和ASP．NET为开发平台,采用RFIO技术和zigbee技术,建立起一个多层次、多用户、多权限的水产品追溯系统。该系统主要由读写器和一个面向对象的信息管理平台组成,其中读写器通过RFID技术读写标签,并采用zigbee技术与上位机的通信,实现数据的读取、查询功能。该系统以水产品供应链中重要采集点的信息为信息源,实现信息的采集、传输、管理、存储、查询等功能。     

“Millipede” – an AFM data storage system at the frontier of nanotribology

The Millipede data storage concept is based on the parallel operation of a large number of micromechanical levers that function as AFM sensors. The technique holds promise to evolve into a novel ultrahigh-density, terabit-capacity, and high-data-rate storage technology. Thermomechanical writing and reading in very thin polymer (PMMA) films is used to store and sense 30–40 nm sized bits of similar pitch size, resulting in 400–500 Gbit/in² storage densities. High data rates are achieved by operating very large arrays (32×32) of AFM sensors in parallel. Batch-fabrication of 32×32 AFM cantilever array chips has been achieved, and array reading and writing have been demonstrated. An important consideration for the Millipede storage project is the polymer dynamics on the size scale of one bit. Scaling of rheological parameters measured for macroscopic polymer samples is likely to be incorrect due to the finite length of the underlying molecular polymer chain, a size that is comparable to the bit itself. In order to shed light on these issues we performed lifetime studies of regular arrays of nanometer size patterns using light-scattering techniques.     

Scanning tunneling microscope combined with scanning electron microscope

A scanning tunneling microscope (STM) has been installed in a usual scanning electron microscope (SEM) with a vacuum of 10⁻⁶ Torr. The STM image is displayed on the cathode ray tube of the SEM, 512 × 512 pixels, with a scanning rate of 80 s/picture. The spatial resolution of the STM is about 1 Å, while that of the SEM is several tens of ångströms. The combined scanning microscope covers a wide magnification range from 10 to 10⁷, where STM covers the high magnification region from 10⁵ to 10⁷.     

A cooling system using wickless heat pipes for multichip modules: Experiment and analysis

The present study is concerned with a cooling package system for electronic components such as multichip modules (MCM) which are used in many electronic system. The im of the cooling capacity up to heat flux of 4 W/cm² was achieved. A heat flux of 4 W/cm² is about two to three times of the value generally accepted as the limit by forced air cooling together with heat pipes (Kishimoto et al., 1994). The data obtained from the experimental program was used to manifest the deficiency and inaccuracies of multitude of the empirical correlations for various heat transfer modes involved in the computer simulation of the proposed system. The dominant role of the temperature distributions in the system and the related two-phase flow heat transfer have been quantitatively identified and the limit of the computer simulation for such system as proposed in the present study has been advanced.     

A monitor for heavy ion flux density control based on detection of recoil protons during irradiation of polymer films

An monitor for control of accelerated particle flux density used in irradiation of polymer films with heavy ions with a low track density (10³?5 × 10⁷ cm^?2) is based on detection of recoil protons. It has been designed to control irradiation of a film with a width of up to 650 mm and is composed of five PIN diodes with a hydrogenous target placed in front of each diode. The sensitivity of the monitor with a polyethylene target to the density of a xenon ion beam is described by a linear function; its value is (4.0±0.5) × 10^?3 pulses/(ion/cm²). The instrument is capable of monitoring ion flux densities of <10⁶ cm^?2, for which all other methods are ineffective. It can be used to determine the track density in a finished product, bypassing the stage of a check with an electron microscope. The signals from the monitor can also be used to introduce a feedback in a system of automatic beam tuning in order to improve the film irradiation quality. The radiation hardness of silicon detectors is ≈ 10¹² protons/cm². At an average detector load of ≈ 10⁴ protons/cm², the average service life of the monitor is 10⁸ s of continuous operation.     

A device for sublimation molecular beam deposition of erbium-doped silicon films

The device described contains a source of Er vapors in the form of a rectangular erbium strip heated to a temperature of 800–950°C by a current passing through it. The base material (Si) flow was produced by sublimation of a silicon bar cut from a single-crystal ingot. The device was used for growing epitaxial Si layers with an Er concentration of 5×10¹⁸–10²¹ cm⁻³.     

超低透过率的测定

本文介绍了用波长为632.8nm的He—Ne激光器作为光源测量透射比小于10^-7/cm²的X光滤光片针孔透射比的方法。为了测量这样低的透过率,我们设计和安装了反射式超低透过率测定装置。用黑色玻璃作为反射式衰减元件,用光电倍增管作为接收器,用数字电压表作为读数仪表。同时,还用中性玻璃滤光片组作为透过式衰减器,也测量了超低透过率。两种方法都得出满意的结果。     

Measuring the surface purity of substrates by the tribometry method

A tribometric device designed for rapid monitoring of the concentrations of atomic and molecular contaminants on the surfaces of semiconductor and dielectric substrates within the range of 10^?7–10^?10 g/cm² is described. The method is based on measurements of the static and sliding friction coefficients between the investigated surfaces. The arrangement of interacting substrates forming a point contact and allowing elimination of disturbances in the crystal structure in the slip region at loads in the range of 0–3.7 N and angles between the substrates of 0–15° is shown.     

Research on the fretting wear behavior of silicon wafers before and after carbon ions implantation

Carbon ions with different doses of 2×10¹⁵ and 2×10¹⁶ ions/cm² were implanted into single crystal silicon wafers under an energy level of 80 keV. The nanohardness and elastic modulus of silicon wafers were studied on the nano-mechanical testing system. The fretting wear tests were performed on the UMT-2 Micro-tribometer to evaluate the fretting wear resistance of C⁺ implanted silicon wafer and to investigate its micro-tribological properties. The results demonstrate that the nanohardness and elastic modulus of silicon wafer with dose of 2×10¹⁵ ions/cm² decreased and those of 2×10¹⁶ ions/cm² changed little. Implanted silicon wafer with dose of 2×10¹⁶ ions/cm² had much lower coefficient of friction and wear volume under low loads, which suggests a significant effect of friction-reducing and anti-wear. The results also indicate that abrasive wear was the main wear mechanism for both virgin silicon and C⁺ implanted silicon with dose of 2×10¹⁵ ions/cm². However, adhesive wear played a significant role in the wear mechanism of the C⁺ implanted silicon with dose of 2×10¹⁶ ions/cm² under the low loads, while the abrasive wear dominated the wear mechanism under high loads.     

A laser spectrometer of field-asymmetric ion mobility

A method for analyzing a substance has been experimentally tested. The method combines the field-asymmetric ion mobility spectrometry and laser ionization of molecules under atmospheric pressure. Pulsed radiation of the fourth harmonic of an YAG: Nd³⁺ laser (λ = 266 nm) and a spectrometer with a cylindrical analysis camera were used. The results of detecting nitrocompounds—trinitrotoluene, cyclotrimethylenetrinitramine (hexogen, RDX), etc.—are presented. The experimental detection limits of the spectrometer are 5 × 10⁻¹⁵ g/cm³ (cyclotrimethylenetrinitramine) and ≤3 × 10⁻¹⁵ g/cm³ (trinitrotoluene).     

基于Android系统的微型光谱仪数据传输及图形化显示

为了满足光谱仪数据采集显示一体化、操作控制智能化的要求,提出了一种基于Android系统的微型光谱仪数据传输及图形化显示的设计方案。该方案是在Android系统平台上进行光谱仪数据采集与嵌入式设备间的串口通信,将采集得到的数据以光谱图的形式显示,并支持数据及图片的保存功能。实验结果表明,该光谱仪可以在Android系统下以115 200bit/s的速度高效采集光谱数据,实时地将数据以光谱图的形式显示出来,并支持数据保存及读取的操作。     

Radio Frequency Technology for Automated Manufacturing and Logistics Control. Part 1: Passive RFID Systems and the Effects of Antenna Parameters on Operational Distance

Identification plays an important role in automation. In the near future radio frequency identification (RFID) will be an option for mass production automation projects. RFID represents a contactless method for data transfer in object identification. Generally, RFID systems consists of three components: 1. A small electronic data carrying device called a transponder, or a tag that is attached to the item to be identified. 2. A reader or a scanner that communicates with the tag by using radio frequency signals. 3. A host data processing system that contains information on the identified item and distributes information to other remote data processing systems. An RFID system can be considered as a wireless communication system because the scanner communicates with the tag by using electromagnetic waves at radio frequencies. The performance of this communication link can be studied by determining the read range for backscatter RFID systems. The read range, or the distance at which the reader unit notices the tag, depends on many factors. Several parameters, e.g. the frequency used for identification, the gain, the orientation and the polarisation of the reader antenna and the transponder antenna, and the placement of the tag on the object to be identified, will all have an impact on the RFID system read range. In this paper, Part 1, we focus on presenting an overview of different passive RFID systems and the read range of the backscatter RFID system. The function of frequency, antenna gain and polarisation mismatch are analysed and discussed. In Part 2, several manufacturing automation cases of different natures will be presented. These cases contain a selection of requirements for an RFID system and they are analysed using the information presented in this paper.     

A Bulk Plasma Generator Based on a Plasma Cathode Discharge

The design, operating features, and parameters of a bulk plasma generator based on a steady-state low-pressure discharge with the additional injection of electrons from an external emitter are described. An additional constricted-arc discharge plasma is used as an electron emitter. This type of a discharge system ensures the formation of a homogeneous and stable gas plasma with a concentration of up to 2 ×10¹⁰ cm^–3 in a volume of 1 m³ at a pressure of up to 3 × 10^–4 Torr in a vacuum chamber. At a discharge current of up to 10 A, its voltage is 100–150 V. The device is characterized by a high efficiency of the energy utilization and a long service life, can operate with chemically active gases, and is easy to adjust and maintain.     

An absolute intensity beam monitor

Based on fast gas electron multipliers, a beam monitor and recording electronics for reading information and transmitting it to the local network was manufactured. The speed of operation of the system is determined by the characteristics of driver amplifiers and equal to ~10⁸ (particle/s)/cm². The operation of the system was tested from a radioactive source.     

MEASUREMENT OF RADIATION INDUCED LOCALIZED ABSORPTION IN CHROMATOGRAPHIC ELUENTS BY MEANS OF THE CO LASER AND THE PZT PYROELECTRIC DETECTOR

Abstract

Combined use of the CO laser and PZT piezoelectric detector is proposed as a sensitive and specific detector for gas chromatography. The feasibility of this detection scheme is demonstrated for a model mixture containing varying proportions of acetone in water. After separation on a GC column, spectra of both constituents were recorded in the 1600 cm^?1 to 1900 cm^?1 range that encompasses the characteristic frequency of C=O bond in acetone. Reasonably high sensitivity (mass concentration limit is 1.2x10^?8 g acetone) and a good degree (factor 530) of spectral discrimination was achieved by a proper selection of analytical wavelengths.