An "ORTHOCORE" magnetic shift register

A method for preparing a batch fabricated integrated magnetic shift register, "Orthocore" is described. The device consists of a complex pattern of printed wires encapsulated in plastic and coated with an electroless magnetic material. Some of the properties required of the material are discussed along with some of the optimum deposition parameters. Substrate considerations such as smoothness and coefficient of expansion are mentioned. The considerations used for a diodeless shift register are described and the design equations are presented. The resulting integrated shift registers are described and their operating conditions are given. The device is shown to have advantage in terms of reliability, cost, and environmental stability.     

A fast Josephson SFQ shift register

A Josephson SFQ (single flux quantum) shift register circuit operating under a two-phase power was designed and tested. The test cell was fabricated using the Nb/AlO_x/Nb junction SNEAP process. The main data latch is DC biased; the data storage is accomplished by the transfer of a single flux quantum in or out of a SQUID (superconducting quantum interference device) superconducting loop. A two-phase sinusoidal clock with offset is used to operate the circuit. Simulations verify that the operating frequency can go beyond 70 GHz, with operating margins exceeding 20%. Preliminary measurements indicate that the circuit operates as intended     

Josephson shift register design and layout

Integrated circuit chips were designed and fabricated, based on a Josephson shift register circuit that simulated operation at 25 GHz using the SPICE program. The 6.25-mm² chip featured a twelve-gate, four-stage shift register fabricated with Nb/AlO_x/Nb Josephson junctions with a design value of 2000 A/cm² critical current density. SUPERCOMPACT, a general program for the design of monolithic microwave integrated circuits, was used to model the effects of layout geometry on the uniformity and phase coherence of logic gate bias currents. A layout geometry for the superconductive transmission lines and thin-film bias resistors was developed. The original SPICE-designed circuit was modified as a result of these calculations. Modeling indicated that bias current variations could be limited to 3% for all possible logic states of the shift register, and phase coherence of the gates could be maintained to within 2° at 10 GHz. The fundamental soundness of the circuit design was demonstrated by the proper operation of fabricated shift registers     

一种专用高速ECL移位寄存器电路的设计和测量

介绍了由先进的多晶硅发射极NPN晶体管和高速ECL100E141电路单元构成的一块专用高速移位寄存器阵列的设计和主要参数的测量.提出一种移位寄存器最高工作频率的测量方法.该方法有效地消除由外部连线和外接器件及测试夹具所造成的寄生延迟对测试结果的影响,准确地测试出电路的最高工作频率.本电路并行输入输出和移位的最高工作频率为410MHz.该电路是为提高某些测试系统高频测量性能而设计的全功能移位寄存器阵列.其布局和结构合理灵活,可以方便地构成多种数据移位寄存方式,有利于使用和测量,具有一定的通用性.     

A nanowire-based shift register for display scan drivers

The development of display scan drivers is an essential step in the effort to develop transparent and flexible display devices based on nanowire transistors. Here we report a transparent nanowire-based shift register that functions as the standard logic circuit of a display scan driver. To form the shift register circuits using only n-type nanowire transistors, a novel circuit structure was introduced to avoid the output voltage drop typical of purely n-type circuits. A circuit simulation based on the measured nanowire transistor characteristics was developed in the planning phase to verify the circuit operation of the shift register. The shift register successfully produced an output of 0-3 V without an output voltage drop while applying an input of 3 V peak to peak. In addition, the shift register was designed to have multiple channels with a randomly oriented nanowire placement method to enhance the operation yield.     

A magnetic shift register employing controlled domain wall motion

A shift register based on controlled domain wall propagation in a magnetic wire with an axial easy direction has been developed. The operational characteristics of an experimental model are discussed. Some hard drawn magnetic materials have been shown to have at least a 3-to-1 nucleation-to-propagation threshold field window over several hundred foot lengths of wire which guarantees operation, This is accomplished without putting the wire under tension. One such promising material is a modified 79-percent Ni, 17- percent Fe, 3-percent Nb, 1-percent Ag, permalloy. An experimental5 times 10^{3}-bit shift register has been constructed with 0.8-mil hard drawn Nb, Ag permalloy and operated at speeds of5 times 10^{3}bps with 12-percent drive current margins. The input power at this rate is approximately 1 mW/bit.     

A two-stage shift register for clocked Quantum-Dot Cellular Automata

Quantum-Dot Cellular Automata (QCA) is a computational scheme utilizing the position of interacting single electrons within arrays of quantum dots ("cells") to encode and process binary information. Clocked QCA architectures can provide power gain, logic level restoration, and memory features. Using arrays of micron-sized metal dots, we experimentally demonstrate operation of a QCA latch-inverter and a two-stage shift register.     

Operation of a 100-bit, 2.6 µm bubble shift register

Complete circuit operation for a small 100-bit serial shift register memory with a 10.6 μm period fabricated on a garnet wafer using electron beam lithography and single level all-permalloy technology is reported. Overall circuit operation including generation, propagation, and detection was achieved with a 6 Oe bias margin using a 1 kHz rotating field. Although the circuit design and fabrication techniques were not optimized, we believe that this is the first published report of complete circuit operation for a single level device with bubbles as small as 2.6 μm. The performance of two different types of chevron expander detectors and two different generators was evaluated and circuits combining disk generators with herringbone detectors were found to provide the best overall operating margin. At low speeds (∼5 Hz) high-bias failures were caused by failure of the domains to strip out fully in the detector while the low bias limit was determined by the introduction of spurious bubbles into the track near the generator.     

The cryogenic multiplexer and shift register for submillimeter-wave digital camera

We have been developing cryogenic readout integrate circuits using SONY GaAs JFETs for large format arrays of high impedance type detectors especially for submillimeter/terahertz astronomy. The GaAs JFETs manufactured by SONY CO. Ltd have excellent static properties at less than 1 K. Besides, these JFETs have good performance for electrical switches; they have very low gate capacitance (<50 fF), low on resistance (∼10 kΩ), and high off resistance (>100 TΩ). To realize a cryogenic readout system for submillimeter-wave/terahertz camera, we designed multiplexers with sample-and-holds and shift registers. We report the first test results of each circuit and show prospect of a cryogenic multiplex system for a submillimeter-wave/terahertz digital camera.     

On nonlinear feedforward shift register and its linear equivalent system

Abstract

In this paper we shall show how we can find a linear system equivalent to a running key generator consisting of a maximum length (ML), a linear feedback shift register (LFSR), and a nonlinear feedforward state filter function. At the same time, a new analysis, which uses a Walsh orthogonal expansion of the state filter function and its relation to the crosscorrelation function (CCF) between the ML‐sequence and the produced running key sequence, is introduced.     

An analysis of the effect of a reliability paradigm shift on leading British aerospace companies

The aerospace industry is moving towards a new paradigm for the statement of reliability specifications. This paradigm is not a technical metric inherent to a system in isolation, but rather encompasses the wider objectives, operational profile and logistic priorities of its customer. This customer focus is encapsulated in the metrics Failure Free Operating Period and Maintenance Free Operating Period. These metrics describe the duration of effective system operation, in the first case for systems where faults and maintenance are permitted and in the second for systems where faults may not be repaired. As part of the Department of Trade and Industry (DTI) funded Aerospace Project for Insertion of Reliability (ASPIRE) research programme, which itself is part of the Ultra Reliable Aircraft (URA) programme, representatives of leading aerospace companies were interviewed about their opinion n how this new reliability paradigm and associated concepts would affect their way of doing business and their engineering processes. It would appear that the aerospace industry is ready for a move to a more realistic set of reliability metrics and away from the old style MTBF based metrics. This sea change would most likely be welcomed by customers, but as yet the manufacturing companies are unconvinced that such a radical move would be a good thing. Much of the resistance to change is due to old‐fashioned, but well entrenched, beliefs in the traditional way of doing things. A move away from this would bring freshness to the industry and lead to cost and time savings as the traditional approach is dropped in favour of a more planned and thought out approach. Copyright © 2002 John Wiley & Sons, Ltd.     

An evolutionary analysis of the innovation policy domain: Is there a paradigm shift?

Scientometrics - Researchers focus on understanding the nature of ecosystems and societies as well as explaining how paradigms change. These efforts are presented and disseminated through scholarly...     

The characterization of magnetic bubble-domain materials with X-ray topography

The use of X-ray topography to characterize magnetic bubble materials is discussed. By mapping the crystal strains, the technique reveals defects which can influence the bubble domains and which are not easily observed by other methods. Examples of topographs are given for flux grown iron garnets, Czochralski grown Gd3Ga5O12substrate crystals, and LPE iron garnet layers. The influence of substrate defects on the magnetic film is demonstrated. Transmission topographs of substrate-film combinations have not revealed an intermediate layer of misfit dislocations. The application of X-ray topography to a study of the growth induced anisotropy in magnetic garnets is also described. The topographs reveal a correlation between regions having a particular growth band symmetry and those having a particular noncubic anisotropy.     

An analytical computation method for statistical tolerance analysis of assemblies with truncated normal mean shift

This paper proposes an analytical solution for fast tolerance analysis of the assembly of components with a mean shift or drift in the form of a doubly-truncated normal distribution. The assembly of components with a mean shift or drift in the form of a uniform distribution (the Gladman model) can be calculated by this method as well since the uniform distribution is a special form of the doubly-truncated normal distribution. Integration formulae of the first four moments of the truncated normal distribution are first derived. The first four moments of the resultant tolerance distribution are then calculated. As a result, the resultant tolerance specification is represented as a function of the standard deviation and the coefficient of kurtosis of the resultant distribution. Based on this method, the calculated resultant tolerance specification is more accurate than that predicted by the Gladman's model or the simplified truncated normal model. The difference between this model and the Monte Carlo method with 1,000,000 simulation samples is less than 0.5%. The merit of the proposed method is that it is fast and accurate which is crucial for engineering applications in tolerance analysis.     

基于蒙特卡洛方法的触发器聚类布局算法

针对触发器聚类的布局问题,提出了一种基于蒙特卡洛方法的触发器聚类布局算法。该方法的核心思想为设计合理的评分函数,并通过蒙特卡洛方法模拟触发器聚类在版图上的随机游走过程,获取样本,再通过评分函数评价样本质量,逐步地在可行域中搜索最优解。实验结果表明,相较于现有的方法,该方法在总线长与时序性能两方面,分别得到平均约9%与17%的改善与提升。此外,该方法具有较强的健壮性,适用于复杂度较高或者版图利用率较高的设计,并能够快速收敛,以较小的时间代价完成优化。     

Discrete cosine transform-based shift estimation for fringe pattern profilometry using a generalized analysis model

What is believed to be a new analysis algorithm to carry out profile measurement with low computational complexity and less noise sensitivity is presented. First, a discrete cosine transform (DCT)-based representation method is introduced to express the height distribution of a 3D surface. Then a novel shift estimation algorithm, called the DCT-based shift estimation (DCT-SE), is presented to reconstruct 3D object surfaces by using the proposed expression and the generalized analysis model. The advantage of DCT-SE is that without loss of measurement precision it provides lower computational complexity to implement 3D reconstruction from nonlinearly distorted fringe patterns and, at the same time, survives the random noise. Simulations and experiments show that the proposed DCT-SE is a fast, accurate, and efficient reconstruction algorithm for digital projection- based fringe pattern profilometry techniques.     

Roles of safety climate and shift work on perceived injury risk: a multi-level analysis

This study evaluated the relationship between employees’ work shift (i.e., day shift versus night shift) and perceptions of injury risk, and how the relationship is affected by company level safety climate and injury frequency. The results showed that night shift workers perceived a higher level of injury risk compared to day shift workers. Both company level safety climate and injury frequency played critical roles in predicting individual perceived work injury risk. Perception of injury risk of night shift workers was significantly lower when they perceived high-level rather than low-level safety climate. However, this pattern was not noticeable for day shift workers. These findings highlighted the importance of considering company level factors when attempting to understand the differences between day shift and night shift work on an individual's perception of injury risk.     

An analysis of a cubic isoparametric transformation

The general nine point isoparametric transformation is analysed with respect to a triangle with two straight sides and one curved side. Point placements are determined on the curved side which ensure that the Jacobian of the transformation remains positive inside and on the boundary of the triangle. Special cases of the transformation are considered which lead to implied curves of the form of symmetric cubics, parabolas, and explicit cubics respectively, thus enabling isoparametric transformations to match a variety of boundary shapes.     

偏场下薄膜体声波谐振器频率偏移的摄动分析

为准确预测测量力、热场的薄膜体声波谐振器(FBAR)传感器的灵敏度,采用叠加于有限偏场之上的小增量场理论描述,提出一种摄动与有限元联合求解方法。该方法利用COMSOL有限元软件计算FBAR传感器受外界载荷下其压电层AlN的平均偏置应力,进一步在COMSOL中计算FBAR的谐振频率与相应的振型,将有限元的计算数据代入摄动积分公式中,得到FBAR传感器的频率灵敏度。并以一个圆膜片FBAR为案例,介绍该方法用于计算圆膜片FBAR频率-集中力灵敏度的详细过程。采用摄动与有限元联合求解方法得到的频率灵敏度为41.3 MHz/N,与文献报道的实验结果 50 MHz/N接近,验证了方法的可行性。     

Core-level shift analysis of amorphous CdTeOx materials

We show the importance of considering the detailed local distributions of oxygen atoms around tellurium in CdTeO _x glasses when interpreting X-ray photoemission experiments. We perform first principles calculations of core-level shifts that are used to compute X-ray photo-electron spectra. The core-level shifts are investigated by means of atomic density of states and a structural Voronoi analysis. We find that the dominating effect on the atomic core-level shift of tellurium is charge redistribution due to the oxygen atoms. There is however also a prominent effect from the geometrical arrangement of the oxygen neighbors.