基于无线传感器网络的土壤墒情监测系统

目前农田监测智能化水平低,管理实时性差,远距离信息传输能力弱、可扩展性不强,且市场上普遍的土壤墒情机一般基于有线连接方式,对于农田监测有一定的局限性,价格昂贵,不适合一般农田的智能化管理。设计了一种土壤监测无线传感网络节点及其远程传输装置,该系统通过PICl8F4520单片机将ARN-100土壤水分传感器、ARN—Tw土壤温度传感器及H311-AS002-T土壤酸碱度传感器采集到的土壤参数处理后,通过ZigBee近距离无线通讯网络以及3G远程无线网络,将数据实时传输给监测终端。测试结果验证了该系统的合理性与实用性,符合现代农业发展方向。     

镀液流速对碳化硅微粒与铜共沉积的影响

本文利用易于控制流速的旋转圆盘电极研究了SiC微粒与Cu的共沉积。得出了在不同镀液流动速度下镀得的复合镀层中微粒含量与镀液中微粒浓度以及与电流密度之间的关系曲线,进而探讨了镀液流速对Cu-SiC共沉积的影响。镀液流速通过影响微粒与阴极之间的弱吸附影响微粒在阴极表面的停留,从而对Cu-SiC复合电沉积过程产生很大影响。     

Diamond growth by carbon ion implantation of diamond

Medium energy (5–25 keV) ¹³C⁺ ion implantation into diamond (100) to a fluence ranging from 10¹⁶ cm⁻² to 10¹⁸ cm⁻² was performed for the study of diamond growth via the approach of ion beam implantation. The samples were characterized with Rutherford backscattering/channelling spectroscopy, Raman spectroscopy, X-ray photoemission spectroscopy and Auger electron spectroscopy. Extended defects are formed in the cascade collision volume during bombardment at high temperatures. Carbon incorporation indeed induces a volume growth but the diamond (100) samples receiving a fluence of 4 × 10¹⁷ to 2 × 10¹⁸ at. cm⁻² (with a dose rate of 5 × 10¹⁵ at. cm⁻² s⁻¹ at 5 to 25 keV and 800 °C) showed no He-ion channelling. Common to these samples is that the top surface layer of a few nanometers has a substantial amount of graphite which can be removed by chemical etching. The rest of the grown layer is polycrystalline diamond with a very high density of extended defects.     

Synthesis and fluorescence properties of aromatic‐aliphatic copolyamides

The aromatic‐aliphatic copolyamides were synthesized by condensation polymerization of aromatic diamine PPD (or APS, where PPD is p‐phenylene diamine and APS is aminophenyl sulfone), aliphatic diamine HDA (or EDA, where HDA is hexanediamine and EDA is ethylenediamine), and TPC (where TPC is terephthalyl chloride) with different molar ratios of aromatic diamine to aliphatic diamine. The steady‐state fluorescence of these condensed copolymers was investigated. These copolyamides exhibit strong blue‐to‐green fluorescence. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 315–321, 2005     

Characterization of end‐functionalized styrene–butadiene–styrene copolymers and their application in modified asphalt

End amino, carboxylic acid, and hydroxyl functionalized styrene–butadiene–styrene (SBS) triblock copolymers were prepared with 1,5‐diazabicyclo[3.1.0]hexane, carbon dioxide, and epoxy ethane as capping agents, respectively. The effects of the end polar groups on the morphology and dynamic mechanical properties were investigated. Transmission electron microscopy images suggested that the group at the end of the polystyrene (PS) segment made the morphology of the PS domains disordered and incompact. Dynamic mechanical results showed that the storage and loss modulus increased after SBS was end‐functionalized. End amino and carboxylic acid groups improved the compatibility and storage stability of SBS‐modified asphalt. However, the effect of the end‐hydroxyl group on the improvement of the storage stability of SBS‐modified asphalt was not obvious. The differential scanning calorimetry analysis of SBS‐modified asphalt further showed that the compatibility and storage stability of SBS‐modified asphalt were improved by the attachment of amino or carboxylic acid groups through the anionic polymerization method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 8–16, 2007     

Prevention from Soft Errors via Architecture Elasticity

Due to the decreasing threshold voltages, shrinking feature size, as well as the exponential growth of on-chip transistors, modern processors are increasingly vulnerable to soft errors. However, traditional mechanisms of soft error mitigation take actions to deal with soft errors only after they have been detected. Instead of the passive responses, this paper proposes a novel mechanism which proactively prevents from the occurrence of soft errors via architecture elasticity. In the light of a predictive model, we adapt the processor architectures h01istically and dynamically. The predictive model provides the ability to quickly and accurately predict the simulation target across different program execution phases on any architecture configurations by leveraging an artificial neural network model. Experimental results on SPEC CPU 2000 benchmarks show that our method inherently reduces the soft error rate by 33.2% and improves the energy efficiency by 18.3% as compared with the static configuration processor.     

CPL: Detecting Protein Complexes by Propagating Labels on Protein-Protein Interaction Network

Proteins usually bind together to form complexes, which play an important role in cellular activities. Many graph clustering methods have been proposed to identify protein complexes by finding dense regions in protein-protein interaction networks. We present a novel framework （CPL） that detects protein complexes by propagating labels through interactions in a network, in which labels denote complex identifiers. With proper propagation in CPL, proteins in the same complex will be assigned with the same labels. CPL does not make any strong assumptions about the topological structures of the complexes, as in previous methods. Tile CPL algorithm is tested on several publicly available yeast protein-protein interaction networks and compared with several state-of-the-art methods. The results suggest that CPL performs better than the existing methods. An analysis of the functional homogeneity based on a gene ontology analysis shows that the detected complexes of CPL are highly biologically relevant.     

An Elastic Architecture Adaptable to Various Application Scenarios

The quantity of computer applications is increasing dramatically as the computer industry prospers. Meanwhile, even for one application, it has different requirements of performance and power in different scenarios. Although various processors with different architectures emerge to fit for the various applications in different scenarios, it is impossible to design a dedicated processor to meet all the requirements. Furthermore, dealing with uncertain processors significantly aggravates the burden of programmers and system integrators to achieve specific performance/power. In this paper, we propose elastic architecture （EA） to provide a uniform computing platform with high elasticity, i.e., the ratio of worst-case to best-case performance/power/performance-power trade-off, which can meet different requirements for different applications. It is achieved by dynamically adjusting architecture parameters （instruction set, branch predictor, data path, memory hierarchy, concurrency, status~zcontrol, and so on） on demand. The elasticity of our prototype implementation of EA, as Sim-EA, ranges from 3.31 to 14.34, with 5.41 in arithmetic average, for SPEC CPU2000 benchmark suites, which provides great flexibility to fulfill the different performance and power requirements in different scenarios. Moreover, Sim-EA can reduce the EDP （energy-delay product） for 31.14% in arithmetic average compared with a baseline fixed architecture. Besides, some subsequent experiments indicate a negative correlation between application intervals＇ lengths and their elasticities.     

基于DNA遗传优化的正交小波常模盲均衡算法

在上行多用户中继网络中,针对中继协作波束成形与多天线基站联合优化的问题,本文提出了两种不同的但是具有一定相关性的设计方法。在第一种方法中,考虑在接收端SINR约束的情况下,使中继节点总功率最小化;在第二种方法中,研究在中继节点满足一定功率约束的情况下,使接收端SINR最大化。研究发现,基站线性接收器的最优权值矩阵决定于中继节点加权向量,进而可将多变量优化的复杂问题转化为单一变量优化问题。原问题进而可转化为半正定规划问题,可以用内点法方便的解决。仿真结果表明,与通过迭代运用凸优化求多向量的方法相比,该方法性能更优。     

基于接收信号强度的非视距检测与修正算法

为了减少非视距（NLOS）误差对基于到达时间（TOA）的无线定位系统性能的影响,本文提出一种采用接收信号强度（RSS）与TOA测量值相结合的方法对含有NLOS误差的TOA测量值进行检测并修正。在视距（LOS）传播的TOA与RSS之间关系已知的前提下,利用定位基站得到的TOA与RSS测量值,计算TOA测量值中含有NLOS误差的可能性,并利用该可能性对TOA测量值进行修正。该方法在不增加通信次数的情况下,大大提高了定位精度。本文最后在一个无线定位系统上实现了该算法,并进行了对比实验。实验结果表明,该算法不需对多次定位结果进行统计,即可有效降低NLOS误差对系统性能的影响,适用于对功耗要求苛刻的场合。