Visible and infrared (1.54 μm) emission from Er-lmplanted porous Si for photonic applications

This paper explores the challenges faced in developing efficient room temperature porous Si-based light emitting diodes. We experimentally demonstrate that porous Si is an excellent host material for erbium ions to emit strong, room temperature, sharp-line luminescence at 1.54 μm. A comparison of photoluminescence data for erbium implanted samples of bulk Si, porous Si, and quartz indicate that quantum confinement likely enhances the erbium IR luminescence efficiency. Due to the 650 to 850°C annealing, it is unlikely that the environment of erbium in our samples is amorphous Si.     

信息技术与美术教学的课程整合

通过开发高校美术教学的网络资源,来转变高校美术学习的模式,同时创建高校美术教学与信息技术整合的新型学习环境,进行研究性学习、相关资料的学习和自主学习。     

高等数学与信息技术的整合探讨

随着社会信息化的不断发展,信息技术已经普遍的应用在了教学之中,信息技术其实也是利用计算机等多媒体来实现教学目的的。在当代的高等数学教学中也会运用到信息技术的整合,这样的整合不仅提高了高等数学的教学质量,还为以后的教学信息化打下了一个坚定的基础。     

电力信息技术与电力通信技术融合策略分析

随着信息时代的到来和科学技术的迅猛发展,我国的各类企业都实现了突破式的发展,电力企业更是实现了技术的革新和发展形态的转变,电力系统的可靠性和工作效率都得到了巨大的提高,这归功于电力信息技术与电力通信技术的融合.本文从电力信息技术与通信技术融合的经济、文化、技术因素分析两者之间的融合环境,并为他们之间的高效融合提供行之有效地策略.     

网络融合─—浅析电信网络的发展趋势

针对目前电信业的发展 ,从技术、市场的角度论述了电信网络的发展趋势 ,对下一代网络进行了展望 :电信网、计算机网、有线电视网的融合 ,技术、市场、业务的融合将是大趋势 .文章还就中国电信在新形式下的发展提出了自己的看法     

Impurity-induced disordering of AIGalnAs quantum wells by low temperature Zn diffusion

We investigated impurity-induced disordering (IID) in AIGalnAs multi-quantum wells (MQWs) on InP substrate by Zn diffusion under low temperature conditions. Blue-shift of band-gap energy of lattice-matched AIGalnAs MQW on InP strongly depended on the temperature of Zn diffusion. The lattice-matched MQW was not completely disordered below 500°C. On the other hand, photoluminescence spectra from compressively strained AIGalnAs MQW, after disordering was independent of the temperature of Zn diffusion. Considerable disordering was observed in the strained MQW, which was saturated even at the low temperature of 400°C. The measured hole concentration of the Zn diffused layer at 400°C was as low as 3 × l0¹⁸cm⁻³ The IID lasers were also fabricated and characterized. No significant increase in the optical loss due to the Zn diffusion was observed in these lasers. On leave from Toshiba Co., Japan.     

射频干扰对消技术在通信系统集成中的应用

介绍了射频干扰对消技术的原理和系统模型,总结了其实现的关键技术点,指出了在通信系统集成中以及任务系统集成中的应用,以及宽带和大动态等未来的发展方向。     

关于机电一体化发展与应用研究

随着现代科技迅猛发展极大推动各个学科相互之间渗透和交叉,导致工程领域出现技术改造.受到急剧发展的微电子技术与计算机技术影响,加之渗透到机械工业,使得机械工程形成机电一体化,机械工业的管理体系、构成、技术结构、生产方式、功能、产品结构都呈现极大变化,这也就使得工业生产从机械电气化过渡到机电一体化阶段.这必须依托相关技术的发展.     

信息技术与各学科教学策略的整合研究

教育部提出,要努力推进信息技术与其他学科教学的融合。信息技术与各学科教学的融合是教育教学改革的核心。文章阐述了信息技术与各学科教学整合的意义、内涵、目的,以及如何在实际教学中采取有效手段进行整合,提出了信息技术与各学科教学整合的3种实施策略。     

On the size of shares for secret sharing schemes

A secret sharing scheme permits a secret to be shared among participants in such a way that only qualified subsets of participants can recover the secret, but any nonqualified subset has absolutely no information on the secret. The set of all qualified subsets defines the access structure to the secret. Sharing schemes are useful in the management of cryptographic keys and in multiparty secure protocols.We analyze the relationships among the entropies of the sample spaces from which the shares and the secret are chosen. We show that there are access structures with four participants for which any secret sharing scheme must give to a participant a share at least 50% greater than the secret size. This is the first proof that there exist access structures for which the best achievable information rate (i.e., the ratio between the size of the secret and that of the largest share) is bounded away from 1. The bound is the best possible, as we construct a secret sharing scheme for the above access structures that meets the bound with equality.This work was partially supported by Algoritmi, Modelli di Calcolo e Sistemi Informativi of M.U.R.S.T. and by Progetto Finalizzato Sistemi Informatici e Calcolo Parallelo of C.N.R. under Grant Number 91.00939.PF69.     

Performance analysis of a low power low noise tunable band pass filter for multiband RF front end

This paper presents a low power tunable active inductor and RF band pass filter suitable for multiband RF front end circuits. The active inductor circuit uses the PMOS cascode structure as the negative transconductor of a gyrator to reduce the noise voltage. Also, this structure provides possible negative resistance to reduce the inductor loss with wide inductive bandwidth and high resonance frequency. The RF band pass filter is realized using the proposed active inductor with suitable input and output buffer stages. The tuning of the center frequency for multiband operation is achieved through the controllable current source. The designed active inductor and RF band pass filter are simulated in 180 nm and 45 nm CMOS process using the Synopsys HSPICE simulation tool and their performances are compared. The parameters, such as resonance frequency, tuning capability, noise and power dissipation, are analyzed for these CMOS technologies and discussed. The design of a third order band pass filter using an active inductor is also presented.     

Conventional and modified TAS/OSTBC schemes in dual‐hop fixed‐gain amplify‐and‐forward relaying systems with imperfect feedback

Modified transmit antenna selection (TAS)/orthogonal space‐time block coding (OSTBC) (M‐TAS/OSTBC) schemes have been shown to achieve superior error performance together with a reduced‐rate feedback channel in the presence of feedback errors (FEs) when compared with the conventional TAS/OSTBC (C‐TAS/OSTBC) schemes. This paper focuses on the bringing of fixed‐gain amplify‐and‐forward (FGAF) relaying schemes that employ M‐TAS/OSTBC schemes at both hops that provides reduced feedback‐rate and robust error performance in the presence of erroneous‐feedback channels. The exact expressions of the outage and error probabilities for both dual‐hop FGAF relaying schemes in Nakagami‐m fading channels have been derived and validated via Monte Carlo simulations. Additionally, with the help of high signal‐to‐noise ratio (SNR) (i.e., asymptotic) approaches and some analytical approximations, the asymptotic diversity order analysis has been carried out. Besides, by providing a simulation‐based examination on the inclusion of power allocation within the modified scheme, the additional advantages on the performance have been exhibited. The extensive investigation and comparisons to the conventional schemes have shown that M‐TAS/OSTBC schemes employed at each transmission link provide full diversity order and considerable error performance as the C‐TAS/OSTBC scheme in ideal feedback cases and also achieve more robust error performance in the presence of FEs. Thus, by using M‐TAS/OSTBC schemes, the overall performances of the dual‐hop FGAF relaying schemes have been enhanced, which would result in reductions on the average SNR requirements to achieve a specified error rate constraint. Copyright © 2015 John Wiley & Sons, Ltd.     

Heteroepitaxial silicon-carbide nitride films with different carbon sources on silicon substrates prepared by rapid-thermal chemical-vapor deposition

Cubic crystalline silicon-carbon nitride (Si_1−x−yC_xN_y) films have been grown successfully using various carbon sources by rapid-thermal chemical-vapor deposition (RTCVD). The characteristics of the Si_1−x−yC_xN_y films grown with SiH₃CH₃, C₂H₄, and C₃H₈ are examined and compared by x-ray photoelectron spectroscopy (XPS) spectra, scanning electron microscopy (SEM) images, and transmission electron microscopy (TEM) patterns. The XPS spectra show that the differences of chemical composition and chemical-bonding state are co-related to the C bonding type of the different carbon source. The SEM images and TEM analysis indicate that the better Si_1−x−yC_xN_y film can be obtained using C₃H₈ gas as the carbon source. In addition, correlations between the growing stages to the microstructure of the cubic-crystalline Si_1−x−yC_xN_y films have been illustrated in detail.     

基于多智能体技术的变电站设备信息集成分析

伴随智能变电站的逐渐发展,变电站设备信息集成成为变电站建设中的一个重要课题.本文围绕多智能体技术,首先对多智能体系统进行简单介绍,然后对基于多智能体技术的变电站设备信息集成设计进行详细论述.     

信息技术与高职教务管理深度融合研究

教务管理是高职院校中的重要部分和核心环节,直接影响着一个学校的教学质量。近年来,由于高职学校的不断扩大,其教学性质也有别于其他高校,教务管理上应与时俱进,将信息技术与教务管理相结合,实现信息化教育,从而更好地提升教学质量和特色教学。文章对信息技术与高职教务管理深度融合进行了研究。     

信息技术与中职教学整合设计的思考

如今,随着网络信息技术的突飞猛进,中等职业学校的信息技术教学也在不断地改进和创新。信息技术作为一项工具,在新课改背景下理应成为为教学服务的重要技术手段,共同致力于教学内容的丰富和教学效率的提高,进而圆满完成各项教学目标。本文密切结合中等职业学校信息技术教学的现状,系统论述信息网络技术与教学整合设计的有效方法,以期为提高信息技术的课堂教学效果提供有价值的参考依据。     

Polishing behaviors of single crystalline ceria abrasives on silicon dioxide and silicon nitride CMP

The effects of single crystalline ceria (CeO₂) abrasives in chemical mechanical polishing (CMP) slurries were investigated for silicon dioxide (SiO₂) and silicon nitride (Si₃N₄) CMP process. The size of ceria abrasives was controlled by varying hydrothermal reaction conditions. Polishing removal rate was measured with four slurries, with different mean primary particle size of 62, 116, 163 and 232 nm. The polishing results showed that the single crystalline ceria abrasives were not easily broken-down by mechanical force during CMP process. It was found that the removal rate of oxide and nitride film strongly depend upon abrasive size, whereas the surface uniformity deteriorates as abrasive size increases. The observed polishing results confirmed that there exists an optimum abrasive size (163 nm) for maximum removal selectivity between oxide and nitride films. The polishing behavior of the single crystalline ceria abrasives was discussed in terms of morphological properties of the abrasive particle.     

数据资源整合系统的应用实现

随着信息化程度的提高,各行各业的积累数据量急剧增长,基于各行业对数据资源整合的需求,提出了一种数据资源整合系统的应用设计架构。该系统采用分层框架技术对资源整合系统的架构进行设计与实现,灵活地解决了各类数据资源整合的问题。结合教育考试数据的资源整合系统的功能模块的设计与实现,实现数据资源整合系统的测试,展示了分层架构设计的灵活性和优势。     

面向云网融合的传输接入及SDN部署策略研究

云业务是运营商实现政企业务突破的关键入口,大力发展云业务驱使运营商快速提升云网一体化服务能力,提供高品质云专线。本文提出面向云网融合的传输OTN、SPN接入方案及传输网络SDN部署策略,为现阶段基于传送网的云网融合部署提供参考借鉴。     

Analytical analysis of IF-penalties for different FSK and CPFSKdetection schemes

Due to the nonnegligible laser linewidth in coherent optical systems, IF bandwidths larger than the Nyquist signaling rate are required. This causes additional sensitivity penalties, which are evaluated for three types of coherent optical FSK (frequency-shift-keying) detection; two-filter-, delay-line discriminator-, and phase-diversity detection. Sensitivity as a function of the relative IF-bandwidth is given in a fully analytical form and confirmed by experimental measurements