基于ZigBee的传感器网络在石化工业中的应用探讨

随着计算机技术、通信技术与网络技术的飞速发展,无线传感器网络受到了国际上的广泛关注.在概述了无线传感器网络的优势及其在石化领域的应用前景基础上,对ZigBee及现有无线通信技术的特性进行了分析.重点介绍了ZigBee技术协议和特点,并利用目前市场上所能提供的器件和开发套件设计出了一种应用于石化工业中的传感器网络方案.最后,通过实验验证了方案的正确性和可行性.     

A variable fidelity information fusion method based on radial basis function

Radial basis function (RBF) model has been widely used in complex engineering design process to replace the computational-intensive simulation models. This paper proposes a variable-fidelity metamodeling (VFM) approach based on RBF, in which different levels fidelity information can be integrated and fully exploited. In the proposed VFM approach, a RBF metamodel is constructed for the low-fidelity (LF) model as a start. Then by taking the constructed LF metamodel as a prior-knowledge and mapping the output space of the LF metamodel to that of the studied high-fidelity (HF) model, a variable fidelity (VF) metamodel is created to approximate the relationships between the design variables and corresponding output responses. A numerical illustrative example is adopted to make a detailed comparison between the VFM approach developed in this research and three existing scaling function based VFM approaches, considering different sample sizes and sample noises. Results illustrate that the proposed VFM approach outperforms the scaling function based VFM approaches both in global and local accuracy. Then the proposed VFM approach is applied to two engineering problems, modeling aerodynamic data for a three-dimensional aircraft and the prediction of weld bead profile in laser welding, to illustrate its ability in support of complex engineering design.     

Role of the Initiation Factors in mRNA Start Site Selection and fMet-tRNA Recruitment by Bacterial Ribosomes

Translation initiation is a complex, multi-step process of fundamental importance in all kingdoms of life, during which the start site of the genetic message transmitted in the form of an RNA molecule (mRNA) is selected, and the level of translation determined. Being the slowest step of protein synthesis, initiation is the phase most often subject to regulation. Here we review, in a historical perspective and focusing mainly on results from our laboratory, the development of our perception of the mechanisms by which the most relevant steps of this pathway occur in bacteria. In particular, we describe: (a) the mechanistics and kinetics of translation initiation; (b) properties of mRNAs with and without Shine–Dalgarno sequence relevant for initiation site selection and translational efficiency; c) ribosomal binding and dissociation of the initiation factors, formation and properties of translation initiation intermediates; (d) the mechanisms by which translation initiation fidelity is ensured. Finally, we provide a short survey of the known translation initiation inhibitors.     

在病理性创伤情况下狗的高频心电图改变

高频心电研究开展已有４０余年的历史，但至今尚无法应用于临床，未获突破性进展问题的实质，在于高频心电形成的因素很多，机理未明，表面上看起来特异性不明显，单靠一般的统计法研究，难以探明高频心电的生成机理，因此高频心电一时还无法作为临床早期诊断的有效方法。本文通过用狗的心脏进行模型实验，研究狗心脏产生人为创伤模拟病变与高频心电表现的确切关系，以及高频心电的可利用性。同时指出，目前国内外部分学者采用统计切迹（ｎｏｔｈ）和转折（Ｓｌｕｒ）的总数来讨论与某些心脏疾病之间关系的方法是不够确切的，因为通过动物试验表明，切迹和转折的数目非心脏病变的唯一标志，告诫对此必须进行十分必要的特征提取。     

以改进影像逼真度为约束条件的变换域水印嵌入强度

在改进影像逼真度透明性指标约束下，对变换域数字水印各AC系数嵌入强度的上限进行了讨论，给出了满足改进影像逼真度约束的嵌入强度上限估计式．该结论及其推论可作为影像逼真度透明性指标的充分条件，用于确定数字水印的嵌入强度(max)的值对值△Fuv及嵌入版本数r等具体参数．实验结果证明了该结论的有效性．     

Broadband Wireless Access Solutions - Progressive Challenges and Potential Valueof Next Generation Mobile Networks

The growth in mobile communication will accelerate over the next years. Today most of the mobile subscribers use cellular services only. But this will change in the near future towards broadband wireless access services like WiFi and WiMAX. This paper describes a fundamental overview of the broadband wireless access technologies and outlines the market view, major trends and introduces OFDM technologies. New developments for integration of broadband wireless access into the operators' infrastructure are also discussed.     

双光子B-J模型中类克尔介质对量子态保真度的影响

研究了充满类克尔介质的高 Q腔中二能级原子与单模相干光场发生双光子相互作用 (双光子 B- J模型 )时 ,类克尔介质对该体系量子态保真度的影响。结果表明 :当类克尔介质与光场耦合较强时 ,原子的量子态保真度为 1,即原子处于退纠缠状态 ,此时光场对原子的作用被类克尔介质所屏蔽。     

非线性光传输系统中损耗对光信号传输的影响

文章采用非线性系统的守恒律和位力定理对光传输系统中损耗对载波光信号传输的影响进行了研究.研究表明,在普通光纤与色散补偿光纤的交界处,孤波的幅度有所降低,但其形状保持不变;光孤子通过放大器后其幅度得到放大,其形状将自动得到恢复.该信号可以高保真地在光纤中传输,具有理想信息载体的特性.     

Smoothing the trail for dissemination of evidence-based practices for youth: Flexibility within fidelity.

The role and implementation of evidence-based practice and empirically supported treatments has been hotly contested among researchers and practitioners. Using examples of and from various empirically supported treatments the authors offer suggestions for smoothing the pathway for dissemination of evidence-based practice with children and adolescents. The authors underscore that mediational analyses, treatment process studies, and the continued creation of flexible treatment manuals are important components of successful dissemination. Flexibility within fidelity is proposed as the preferred perspective that eases the transition and dissemination of empirically supported treatments from research clinics to service clinics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)