一种改进的认知域自适应干扰温度估算算法

从认知无线电通信接入、干扰回避和功率控制的角度出发,采用自适应谱线增强技术对基于多窗口谱估计的干扰温度估算算法进行了改进,并进一步推导了功率谱与干扰温度的关系.依托符合IEEE 802.11G标准的无线环境对算法进行了性能仿真,仿真结果表明,改进算法具有较好的检测性能,提高了干扰温度估算的精度和可信度,具有一定的实际应用价值.     

无线电通信抗干扰方法研究

针对传统方法在应用时无线电通信误码率较高,为此提出无线电通信抗干扰方法研究。建立无线电通信模型,用来表示无线电通信信道传输过程;然后对混合通信信号进行去均值化和预白化处理,将无线电通信信号均值处理为零,并且对混合信号中冗余信息的压缩和去除;计算无线电通信信号高阶累积量和归一化峭度特征值,分析无线电通信信号高斯分布的偏离程度;根据提取到的特征参数,利用分离算法对无线电通信信号进行计算,将无线电通信信号从干扰信号中分离出来,以此实现了无线电通信抗干扰。实验结果表明,应用此次设计方法后无线电通信误码率低于传统方法,更适用于无线电通信抗干扰。     

谈谈海上无线电通信

谈谈海上无线电通信段作军我们知道，船舶航行于世界的各个海区，无线电局信对于航行安全和进行各种业务显得尤其重要，因此，先进的无线电通信技术，都较早地应用于海上通信。不同的通信方式在船岸电台上的应用，要求对其有统一的管理，下面就从几个方面分别介绍。一、呼...     

基于区块链与可信度函数的电子加密信息上链存储方法

为优化加密信息在区块链的存储空间占比，提高上链存储速度，提出了基于区块链与可信度函数设计电子加密信息上链存储方法。建立基于区块链和可信度函数的信息加密分类模型，获取溯源凭证判定函数，对电子信息进行代理重加密；计算集群存储空间容量，使用加密密文直接匹配访问结构树；区分主体可信度与客体可信度，基于可信度函数分类电子加密信息，设计电子加密信息上链存储方法。实验结果表明，应用所提方法后，当文件数量在1 000～10 000个时，数据存储速度最快，存储空间占比以及存储速度上均有较大优化。     

让电波在自己的轨道上驰骋

在科技迅速发展的今天，无线电通信已深入到包括人们日常生活在内的各个领域。无论是天上的飞机、卫星、海上的轮船舰艇、陆地上的各种车辆，还是人们熟悉的收音机、电视机，或是“大哥大”、BP机等等，全都离不开无线电通信技术。业余无线电通信是整个无线电通信世界当中一个重要的组成部分。它是一项鼓励人们去从事无线电收信和发信实践的业余兴趣爱好活动。联合国下设的国际电信联盟ITU根据不同的用途，将全世界所有无线电通信分为若干种业务，业余无线电通信属于其中的“业余业务”。ITU对业余业务的定义为：供业余无线电爱好者进行…     

编队防御敌通信侦察的解析模型及分析

在未来高技术海战中，海上编队将面临敌电子信息攻击，敌我双方主要在短波、超短波无线电通信对抗范围内进行争夺。探讨舰艇编队的通信反侦察，研究通信反侦察的措施，为海上编队通信电子防御的指挥决策与组织实施提供依据和参考，以进一步增强编队通信防御能力。     

浅析甚高频数据交换系统

随着软件无线电技术的发展、E-航海概念的引入,使航运业对水上无线电通信数字化、高速化、宽带化的要求越来越高,甚高频数据交换系统(VDES)是国际航标协会航海委员会提出的,VDES对于海上信息服务有重要意义,包括海上救援和海上交通,是E-航海的关键所在.本文通过研究国际重要会议的相关提案,对VDES的提出背景、组成内容及实施路线进行了整理阐述.     

海上目标航向航速解算新方法

航向航速是海上目标的重要特征,能准确获取目标的航向航速对于海上目标的跟踪和识别具有非常重要的意义。当雷达载体具有较高运动速度时,雷达测量的目标位置信息是非线性的,并且海上目标运动速度慢,在短时间内,受雷达测量精度的限制,目标位置的微小变化量很难精确估算,此时需要建立精度较高的非线性滤波模型,利用卡尔曼滤波方法,提高目标位置信息的估计精度。针对单脉冲雷达,本文提出了一种实时性强,工程上易于实现的海上目标航向航速的解算方法,推导了雷达载体高速运动条件下跟踪目标的滤波方程,采用卡尔曼滤波方法提高了目标位置估算精度。紧密结合工程背景,利用雷达载体的GPS信息和目标测量信息实现了海上目标航向航速的高精度解算。分析了解算数据长度对解算精度的影响,并给出了不同目标选择数据长度的经验公式。最后,通过海上目标在不同场景下的仿真实验,验证了本文方法的有效性和正确性。      

一种认知无线电通信模型的研究

认知无线电通信系统能够感知法定授权用户的活跃性,利用空闲频谱进行信息传输。文章建立了一个新型的认知无线电通信模型,然后对模型链路吞吐量进行仿真,结果表明模型的感知范围和链路吞吐量之间存在一个折衷,选择合适的感知半径和分布式距离可以获得较大的吞吐量。     

浙江宁波市无管局开展港区海上无线电通信安全演练

本刊讯 5月28日,浙江宁波市无线电管理局联合宁波港股份有限公司,在北仑大榭岛附近海域开展了保护宁波港区海上无线电通信安全演练. 此次演练的目的是加强宁波港区无线电通信安全与水上频率保护工作,保障宁波港区各类无线电通信正常工作,确保船舶航行安全,同时通过具体实施《保护宁波港区无线电通信安全工作机制》发现问题,完善预案.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.