Self‐Compensation in Transparent Conducting F‐Doped SnO2

The factors limiting the conductivity of fluorine‐doped tin dioxide (FTO) produced via atmospheric pressure chemical vapor deposition are investigated. Modeling of the transport properties indicates that the measured Hall effect mobilities are far below the theoretical ionized impurity scattering limit. Significant compensation of donors by acceptors is present with a compensation ratio of 0.5, indicating that for every two donors there is approximately one acceptor. Hybrid density functional theory calculations of defect and impurity formation energies indicate the most probable acceptor‐type defects. The fluorine interstitial defect has the lowest formation energy in the degenerate regime of FTO. Fluorine interstitials act as singly charged acceptors at the high Fermi levels corresponding to degenerately n‐type films. X‐ray photoemission spectroscopy of the fluorine impurities is consistent with the presence of substitutional F_O donors and interstitial F_i in a roughly 2:1 ratio in agreement with the compensation ratio indicated by the transport modeling. Quantitative analysis through Hall effect, X‐ray photoemission spectroscopy, and calibrated secondary ion mass spectrometry further supports the presence of compensating fluorine‐related defects.     

Using Data Contention in Dual-ported Memories for Security Applications

Field Programmable Gate Arrays (FPGA) provide the invaluable feature of dynamic hardware reconfiguration by loading configuration bit files. However, this flexibility also opens up the threat of theft of Intellectual Property (IP) since these configuration files can be easily extracted and cloned. In this context, the ability to bind an application configuration to a specific device is an important step to prevent product counterfeiting. Furthermore, such a technology can also enable advanced business models such as device-specific feature activation. In this work, we present a new technique to generate entropy on FPGA device—based on data contention in the hardware circuitry. For this entropy, we use the output of intentionally generated write collisions in synchronous dual-ported block RAMs (BRAM). We show that the parts of this output generated by such write collisions can be either probabilistic but also deterministic and device-specific. The characteristics of such an entropy source can be used for a large variety of security applications, such as chip identification and device authentication. In addition to that, we also propose a solution to efficiently create cryptographic keys on-chip at runtime. As a last contribution, we eventually present a strategy how to transform this entropy source into a circuit for True Random Number Generation (TRNG).     

平板投影光楔的图象质量

我们报道了一种厚度为20mm的14英寸平板投影显示屏,其亮度可达5000尼特、分辨率为600×800。这种显示器由现成的有机玻璃制成,使用只带梯形预畸变的无需调节的视频投影仪。在厚度为20mm对角线为50英寸屏幕上光学模拟预示XGA分辨率,亮度为500尼特、对比度与传统投影仪相当。     

Lithium Phosphonate Functionalized Polymer Coating for High-Energy Li[Ni0.8Co0.1Mn0.1]O2 with Superior Performance at Ambient and Elevated Temperatures

High-energy Ni-rich lithium transition metal oxides such as Li[Ni_0.8Co_0.1Mn_0.1]O₂ (NCM₈₁₁) are appealing positive electrode materials for next-generation lithium batteries. However, the high sensitivity toward moist air during storage and the high reactivity with common organic electrolytes, especially at elevated temperatures, are hindering their commercial use. Herein, an effective strategy is reported to overcome these issues by coating the NCM₈₁₁ particles with a lithium phosphonate functionalized poly(aryl ether sulfone). The application of this coating allows for a substantial reduction of lithium-based surface impurities (e.g., LiOH, Li₂CO₃) and, generally, the suppression of detrimental side reactions upon both storage and cycling. As a result, the coated NCM₈₁₁-based cathodes reveal superior Coulombic efficiency and cycling stability at ambient and, particularly, at elevated temperatures up to 60 ° C (a temperature at which the non-coated NCM₈₁₁ electrodes rapidly fail) owing to the formation of a stable cathode electrolyte interphase with enhanced Li⁺ transport kinetics and the well-retained layered crystal structure. These results render the herein presented coating strategy generally applicable for high-performance lithium battery cathodes.     

Lone‐Pair‐Induced Covalency as the Cause of Temperature‐ and Field‐Induced Instabilities in Bismuth Sodium Titanate

Bismuth sodium titanate (BNT)‐derived materials have seen a flurry of research interest in recent years because of the existence of extended strain under applied electric fields, surpassing that of lead zirconate titanate (PZT), the most commonly used piezoelectric. The underlying physical and chemical mechanisms responsible for such extraordinary strain levels in BNT are still poorly understood, as is the nature of the successive phase transitions. A comprehensive explanation is proposed here, combining the short‐range chemical and structural sensitivity of in situ Raman spectroscopy (under an applied electric field and temperature) with macroscopic electrical measurements. The results presented clarify the causes for the extended strain, as well as the peculiar temperature‐dependent properties encountered in this system. The underlying cause is determined to be mediated by the complex‐like bonding of the octahedra at the center of the perovskite: a loss of hybridization of the 6s² bismuth lone pair interacting with the oxygen p‐orbitals occurs, which triggers both the field‐induced phase transition and the loss of macroscopic ferroelectric order at the depolarization temperature.     

A G/sub m/-C low-pass filter for zero-IF mobile applications with a very wide tuning range

A third-order G/sub m/-C Butterworth low-pass filter implementing G/sub m/-tuning and G/sub m/-switching to maximize the tuning range is described. This filter is intended to be used as a channel-selection/anti-aliasing filter in the analog baseband part of a zero-IF radio receiver architecture for multimode mobile communications. Its G/sub m/-switching feature allows extending the tuning range and adapting the power consumption. The filter's cutoff frequency ranges from 50 kHz to 2.2 MHz. An Input IP3 of up to +18 dBV/sub p/ is achieved, for a total worst-case power consumption of 7.3 mW for both I and Q paths, and an effective area of less than 0.5 mm/sup 2/ in a 0.25-/spl mu/m SiGe BiCMOS process. A new figure of merit is introduced for comparison of published low-pass tunable filters including noise, linearity, and tuning range.     

eFeed-Hungers.com: Mitigating global hunger crisis using next generation technologies

Hunger is a global crisis and impacting the world for a very long time. Significant efforts have been made in the past by various organizations employing various means to address this persisting problem. Despite this, it still remains far from being resolved. Recently, the United Nations has published a report on global hunger, which claims that the global food production is fairly enough to feed the entire world with a population of about 7.3 billion. However, a major quantity of the food grown is not channeled appropriately and effectively to reach the needy and thus gets wasted unfortunately. Using the advanced computer technologies, we devise and develop a web-based computational framework (eFeed-Hungers.com) that serves as a bridge between the food waste and the hunger to mitigate the hunger issue; the food waste is the excess, unused, edible food, which otherwise is destined to the dumpster unfortunately. The eFeed-Hungers.com encourages and assists the food waste donation announcements with the least minimal efforts with the best possible outreach. Through the eFeed-Hungers.com, the food donations are globally searchable by the needy, with enough additional information imparted for quick decisions making to fetch the appropriate donated food. The eFeed-Hungers.com is envisioned to be a fully functional organization eventually with global outreach.     

Dynamic Policy-Based Network Management for a Secure Coalition Environment

This article reports the latest results of an R&D effort to develop a prototype implementation of a dynamic policy-based network management (PBNM) system that can be used to configure and manage a secure network for a coalition environment across an unsecured wide area network. The prototype, based on a distributed architecture, includes capabilities for policy creation and management, dynamic policy negotiation, and dynamic policy provisioning. The policy negotiation facilitates the rapid deployment of a coalition network while the dynamic policy provisioning automates the configuration and management of network services including firewalls, virtual private network connections, routing, quality of service (QoS), and domain name services. Such a PBNM system enhances an organization's ability to react to network incidents identified by a network situational awareness assessment. Although the focus of the current research is a military coalition environment, the system can be used in any distributed enterprise or collaborative environment