A model for retention on short, intermediate and long time-scale in ferroelectric thin films

We developed a model with no adjustable parameter for retention loss at short and long time scale in ferroelectric thin-film capacitors. We found that the predictions of this model are in good agreement with the experimental observations in the literature. In particular, it explains why a power-law function shows better fitting than a linear-log relation on a short time scale (10^-7 s to 1 s) and why a stretched exponential relation gives more precise description than a linear-log plot on a long time scale (>100 s), as reported by many researchers in the past. More severe retention losses at higher temperatures and in thinner films have also been correctly predicted by the present theory.Comment: 15 pages and 3 figure

Unipolar and bipolar fatigue in antiferroelectric lead zirconate thin films and evidences for switching-induced charge injection inducing fatigue

For the first time, we show that unipolar fatigue does occur in antiferroelectric capacitors, confirming the predictions of a previous work [Appl. Phys. Lett., 94, 072901 (2009)]. We also show that unipolar fatigue in antiferroelectrics is less severe than bipolar fatigue if the driving field is of the same magnitude. This phenomenon has been attributed to the switching-induced charge injection, the main cause for polarization fatigue in ferroelectric and antiferroelectric materials. Other evidences for polarization fatigue caused by the switching-induced charge injection from the nearby electrode rather than the charge injection during stable/quasi-stable leakage current stage are also discussed.Comment: 10 pages and 2 figure

On Robust Stability of Limit Cycles for Hybrid Systems with Multiple Jumps

In this paper, we address stability and robustness properties of hybrid limit cycles for a class of hybrid systems with multiple jumps in one period. The main results entail equivalent characterizations of stability of hybrid limit cycles for hybrid systems. The hybrid limit cycles may have multiple jumps in one period and the jumps are allowed to occur on sets. Conditions guaranteeing robustness of hybrid limit cycles are also presented

An Internal Control Evaluation Tool For Advertising Revenue In The Newspaper And Magazine Publishing Industry

Even before the recent economic downturn, the newspaper and magazine publishing industry had been experiencing unprecedented change, with some companies facing an immediate need to either invent a new business model or else cease operations.  The current economic slowdown has, in many cases, exacerbated those challenges.  These trends have had the effect of increasing the risk of fraudulent financial reporting.  The revenue cycle continues to be one of the most important areas for auditors to examine for possible fraud and one for which strong, comprehensive internal controls are especially important (AICPA 2002).  This paper presents an internal control review checklist for advertising revenue in the newspaper and magazine publishing industry.  This checklist may be used by independent auditors as a general benchmark in performing a preliminary evaluation of a company’s internal controls over advertising revenue.  In instances where important internal controls on the checklist have been omitted from the client’s system, the auditor should consider whether the omission increases audit risk.  The checklist may also be used by CFOs or controllers in the industry to help determine whether their company’s internal control system is adequate

Phase Separation of Bismuth Ferrite into Magnetite under Voltage Stressing

Micro-Raman studies show that under ~700 kV/cm of d.c. voltage stressing for a few seconds, thin-film bismuth ferrite BiFeO3 phase separates into magnetite Fe3O4. No evidence is found spectroscopically of hemite alpha-Fe2O3, maghemite gamma-Fe2O3, or of Bi2O3. This relates to the controversy regarding the magnitude of magnetization in BiFeO3.Comment: 9 pages and 2 figure

Redundancy relations and robust failure detection

All failure detection methods are based on the use of redundancy, that is on (possible dynamic) relations among the measured variables. Consequently the robustness of the failure detection process depends to a great degree on the reliability of the redundancy relations given the inevitable presence of model uncertainties. The problem of determining redundancy relations which are optimally robust in a sense which includes the major issues of importance in practical failure detection is addressed. A significant amount of intuition concerning the geometry of robust failure detection is provided

Electrical Detection of Spin Accumulation at a Ferromagnet-Semiconductor Interface

We show that the accumulation of spin-polarized electrons at a forward-biased Schottky tunnel barrier between Fe and n-GaAs can be detected electrically. The spin accumulation leads to an additional voltage drop across the barrier that is suppressed by a small transverse magnetic field, which depolarizes the spins in the semiconductor. The dependence of the electrical accumulation signal on magnetic field, bias current, and temperature is in good agreement with the predictions of a drift-diffusion model for spin-polarized transport.Comment: Submitted to Phys. Rev. Let

Corporate Inversions And Fair Play

A Corporate inversion is a process that a company undergoes to change the domicile of the parent corporation in a multinational corporate conglomerate to a country other than the United States. J. S. Barry (2002) quotes U.S. Senator Max Baucus, Chairman of the Senate Finance Committee, as saying: "Prominent U.S. companies are literally re-incorporating in off-shore tax havens in order to avoid U.S. taxes. They are, in effect, renouncing their U.S. citizenship to cut their tax bill. This is very troubling, especially now, as we all try to pull together as a nation." Senator Charles Grassley (R-Iowa), the ranking Republican member of the Finance Committee, has called inversions "immoral." Stanley Works, a corporation based in Connecticut, planned to re-incorporate in Bermuda. A Democratic Representative from that state, James Maloney, said, "Connecticut hasn't seen such a shameful day since Benedict Arnold sailed away." Stanley Works buckled under political pressure and did not go forward with the planned inversion. This paper addresses the current practice of corporate inversions, and reviews the current legal and political actions taken to address them

Revenue Process Internal Control For Manufacturers: An Evaluation Tool For Independent Auditors And Managers

Effective management of the revenue process is critical to the success and long-run viability of any business.  The revenue process also entails an elevated risk area for financial reporting fraud (AICPA 2002; Beasley et al., 2010).  Accordingly, this important process demands heightened attention from independent auditors and company managers, and internal control activities must be considered as part of the ongoing evaluations of this important area.  This paper presents a tool for evaluating internal control objectives and activities pertinent to the revenue process for companies operating in the manufacturing sector.  This evaluation tool may be used by independent auditors as a general benchmark in performing a preliminary evaluation of a manufacturing client’s internal control over the revenue process.  Independent auditors who will find the tool most useful will primarily be those wishing to comply with U.S. Generally Accepted Auditing Standards (GAAS), including those performing integrated audit engagements in accordance with Public Company Accounting Oversight Board (PCAOB) Auditing Standard No. 5 and the new requirements set forth in the Committee of Sponsoring Organizations of the Treadway Commission’s (COSO) Internal Control – Integrated Framework.  In instances where important internal control activities have been omitted from the client’s system, the auditor should consider whether the omission increases the risk of material misstatement.  This tool may also be used by managers to evaluate the adequacy of their company’s internal control activities within the revenue process

An Internal Control Evaluation Tool For The Construction Industry

This paper presents a Control Objectives Reconciliation, a tool that independent auditors of clients in the construction industry should find useful in performing a preliminary evaluation of the client’s internal control system.  Auditors are advised to compare their client’s control objectives with those presented in Exhibits 1 through 7.  Where the client’s system appears to omit significant control objectives, the auditor should consider the risks brought on or magnified by the omission during the preliminary evaluation of the client’s internal control system.  The Control Objectives Reconciliation is also potentially useful to Construction Company CFOs or Controllers who may be concerned about the adequacy of their company’s internal control system.  The Reconciliation also highlights for Construction Company CFOs or Controllers those internal controls deemed to be important to their external, independent auditors