Host/guest complex of Me-β-CD/2,2-dimethoxy-2-phenyl acetophenone for initiation of aqueous photopolymerization: Kinetics and mechanism

Methylated-β-cyclodextrin (Me-β-CD) was used to complex the photoinitiator, 2,2-dimethoxy-2-phenyl acetophenone (DMPA), yielding a water-soluble host/guest complex. The comparative studies demonstrated that the Me-β-CD complexed DMPA exhibited a high photoreactivity identical to the uncomplexed DMPA, while the CD complex obviously influenced the products of primary photolysis of DMPA and the photopolymerization kinetics due to the steric effect of CD on the subsequent initiation reactions. The photopolymerization rate of acrylamide can be described by the equation: R_p=K[2a]^0.62[M]^1.37[I]^0.5[Me-β-CD]⁰. The mechanism of polymerization was also discussed.     

3.5代通信中链路自适应技术的研究和仿真

3.5代移动通信中的链路自适应技术使用自适应调制编码和快速混合重传技术替代了3代中使用的功率控制技术。仿真结果比较了这两种新技术与功率控制技术的性能,证明了这两个新技术显著地提高了网络平均的吞吐量。     

DSU与DSU采集链

文章介绍了超精度的新型地震传感器DSU，它由微机电系统(MEMS)和兼有模拟电路和24位△—∑数字电路的混合器件(ASIC)组成，其失真度可达0．0032％，响应频带0～800Hz。DSU采集链使采集站、大线和检波器合为一体，既消除了电磁干扰和道间串音，又提高了采集数据的精度。DSU及DSU采集链的应用将为地震采集技术向超精度发展提供可靠保证。     

用C语言链表解决大整数运算的精度问题

介绍用C语言链表解决大整数运算的精度问题的方法。     

计算机网络安全扫描技术研究

随着互联网技术的发展,网络安全问题日益突出。作为一种主动防御手段,网络安全扫描技术在保护网络安全方面发挥着越来越大的作用。本文主要对主机探测,端口扫描,操作系统探测以及漏洞扫描等四种主要的网络安全扫描技术做了研究。     

关于节目主持人形象塑造教学过程中的技巧探析

节目主持人的形象直接影响着整个节目的质量,文章针对节目主持人形象问题的塑造展开了研究和分析,同时结合在实际教学中经常出现的问题,从主持人形象要求教学模式的实际情况出发,阐述和分析了主持人形象塑造教学过程中的教学技巧和方法。     

基于Host Link FINS协议的PLC远程通信

以欧姆龙公司CP1H型号的PLC为应用背景,设计了基于Host Link FINS协议的PLC设备远程监控系统.该文提出了基于串口的远程通信方案,并且详细分析了Host Link FINS协议的结构和指令格式,用MFC实现了监控软件的设计,完成监控软件与欧姆龙PLC的数据通信功能,实现监控软件对PLC的远程监控.经过现场的测试和运行,该监控系统稳定可靠,性能较高.     

Inhibitory Effect of Monoterpenes on Response of Pityogenes bidentatus to Aggregation Pheromone Released by Piezoelectric Sprayer for Precision Release of Semiochemicals

A piezoelectric sprayer for dispensing semiochemicals was developed and used for a field test of bark beetle semiochemicals. The sprayer consists of a geared pump that pushes a syringe slowly to dispense semiochemicals in solvents through a microtube to a glass micropipet fixed to a piezoelectric high-frequency vibrator. The frequency is adjusted via a function generator to about 120 kHz until the harmonic properties of the glass micropipet, drawn by an electrophysiological pipet puller, cause vibrations that atomize the solvent from the micropipet tip. The sprayer, syringe, pump, function generator, and power supply were hung on one arm of a rotating trap pair (traps 6 m apart) that was slowly rotated at 2 revolutions per hour (rph) to even out the position effects on trap catches. The aggregation pheromone components of Pityogenes bidentatus, grandisol and cis-verbenol, were released by standard tube dispensers in one trap and compared to the release of similar amounts by the sprayer in the other trap. No significant differences in catch were observed. No effect of the solvent hexane on aggregation could be observed. The trap pair also caught approximately equal numbers of bark beetles when the baits were identical. The release of (+)and (–)--pinene, (+)-3-carene, and terpinolene, monoterpenes of host Scotch pine, Pinus sylvestris, at increasing rates from 0.01 to 10 log-equivalents in decadic steps (each at 0.1–100 g/min) resulted in decreasing responses to aggregation pheromone (only 9% at highest rate). Inhibition by the individual monoterpenes tested at the 100 g/min rate was significant for (+)and (–)--pinene and terpinolene (12, 13, and 15% of control, respectively). The inhibition by the host Scotch pine monoterpenes may allow P. bidentatus to avoid resistant trees that release large amounts of toxic monoterpenes in their resin and instead colonize dying and diseased limbs or slash, the usual host substrate. The piezoelectric sprayer should prove generally useful to dispense precise amounts of semiochemicals in field and laboratory experiments.     

Characterization of chemicals mediating ovipositional host-plant finding byAmyelois transitella females

Ovipositional host-finding in the navel orangeworm,Amyelois transitella (Walker), is brought about by an in-flight response to host odors. Wind-tunnel studies of the response of gravid females to almonds showed that this response is mediated primarily by long-chain fatty acids, particularly oleic acid and linoleic acid. Evidence for the behavioral activity of fatty acids is based on the fact that: (1) behavioral activity of almond oil was concentrated in a single liquid chromatographic fraction whose composition was predominantly long-chain fatty acids, (2) behavioral activity was lost when either almond oil or the active fraction of that oil was treated with diazomethane, (3) full activity was elicited by a selective extraction of free fatty acids from crude almond oil, and (4) upwind response by females was elicited by a blend of synthetic oleic and linoleic acids, albeit at a level less than that elicited by almond oil. Five fatty acids identified from the almond oil were: myristic acid (1%), palmitic acid (16%), stearic acid (3%), oleic acid (58%), and linoleic (22%). Attraction to various combinations of synthetic acids was observed only when oleic acid was present, and oleic acid elicited upwind flights to the source when presented alone; however, short-range responses were enhanced by the addition of linoleic acid, which elicited no long-range orientation by itself. Despite significant levels of attraction to synthetic blends, the percentage of females flying to the source was lower than that flying to acidulated almond oil, the best natural attractant tested. Thus, although longrange response may be mediated primarily by a blend of oleic and linoleic acids, additional and as yet unidentified components must also play an important role. Long-range chemically modulated host finding in this and other generalist plant feeders is discussed with respect to current models of the evolution of host finding, and it is argued that suggestions that long-range host finding should be correlated with narrowness of host utilization are logically flawed and are not supported by our current understanding of specific examples of host finding.     

基于改进AdaBoost算法的复杂网络链路预测

链路预测是复杂网络的重要研究方向,当前的链路预测算法因可利用的网络信息有限,导致预测算法的精确度受限。为了提高预测算法的性能,采用改进的AdaBoost算法进行链路预测。首先根据复杂网络样本建立邻接矩阵,完成样本的矩阵化处理;然后采用AdaBoost算法进行分类训练,通过权重投票获取预测结果;最后,考虑到复杂网络弱分类器预测正负误差分布的不均衡问题,设置权重调整因子η及其调整范围[η1,η2],并根据η值动态调整AdaBoost算法的多个弱分类器分类结果的权重,从而获得准确的链路预测结果。实验结果证明,相比其他常用网络链路预测算法及传统AdaBoost算法,改进的AdaBoost算法的预测准确率优势明显,且在节点数量较多时,其预测时间性能和其他算法的差距较小。