Risk factors in oil and gas industry returns: International evidence

The recent boom in oil prices has attracted many investors to oil companies in search of both returns and diversification benefits. This analysis of the risk factors of investing in the oil and gas industry in 34 countries finds evidence that oil price is a globally priced factor for the oil industry. The oil and gas sector in developed countries responds more strongly to oil price changes than in emerging markets. Oil and gas industry returns also respond asymmetrically to changes in oil prices; oil price rises have a greater impact than oil price drops. There is no parallel to the asymmetry of oil price changes in other industries related to commodities. If there is any asymmetry, it is in the opposite direction from oil. Negative commodity price changes have a greater impact than positive ones. The results seem to indicate that the oil and gas industry is distinguished by a pass-through effect.     

基于PIC16C72的水位水温控制器的设计

为满足落水式太阳能热水器自动控制的要求,设计了一个基于PIC16C72单片机的水温水位控制器。以NTC热敏电阻作为测温传感器,用PIC16C72内置的多路8位A/D转换器把NTC热敏电阻上的压降转换为数字量实现测温。通过非对称多谐振荡器电路把水位传感器的等效电阻转换为振荡信号的频率,然后用PIC16C72内置的计数器测量频率的高低,实现对水位的测量。介绍了控制器的工作原理、完整的硬件电路和功能。该设计省去了温度测量信号调理电路、专用A/D转换和输出译码驱动芯片,具有硬件系统组成简单、可靠性好的特点。     

基于XC3S1600E的实时数据采集与处理系统

本文主要介绍了一种基于FPGA的USB总线技术的双通道数据采集系统设计方案,该方案采用Spartan3E XC3S1600E作为核心处理芯片,使用FPGA内部的软核及状态机把各个模块有效的连接起来。     

基于FPGA的星载电场仪信号处理系统设计

为了构建空间电场测量体系,设计了基于FPGA的星载电场仪信号处理系统。区别于探空火箭电场信号测量系统,星载电场仪系统采用XilinxFPGA为主控制器和数据处理单元,同时针对星上环境提出了偏置电流源和浮动参考地等独特设计。文章介绍了系统的硬件设计和软件设计。测试结果表明,系统稳定可靠,具有一定的参考价值和实际应用价值。     

Influences of gold and silver nanoparticles in loop-mediated isothermal amplification reactions

Loop-mediated isothermal amplification (LAMP) performed with protein DNA polymerase Bst and DNA chains was influenced by nanoparticles in different ways. The effects of different concentrations of gold nanoparticles (AuNPs) with diameters 10 and 20?nm and silver nanoparticles (AgNPs) 1–10?nm in diameter on the amplification of the pR72H gene of Vibrio parahaemolyticus were investigated. AuNPs with a diameter of 10?nm in 0.6–60?nM concentration accelerated initiation of the LAMP reaction, 3?nM AuNPs reduced the reaction time by about 10?min, whereas 20?nm AuNPs did not, although neither size increased the yield after 60?min. AgNPs inhibited the LAMP reaction both in speed and yield at concentrations of 0.6–60?nM; the yield of amplification was reduced by 50% and 80% for 12 and 60?nM, respectively, after reaction for 1?h. This indicated that strong bactericidal effects of silver are also observed in its nanoparticles. The molecular mechanism of AuNPs and AgNPs in LAMP needs to be explored further, although their size-related electronic, magnetic and optical properties, as well as their ability to affect protein denaturation, or hydrophilic/hydrophobic effects may be involved.     

非晶 Ni_(19)Zr_9Al_(72) 合金表面状态的研究

采用俄歇电子能谱（ＡＥＳ）,Ｘ射线光电子能谱（ＸＰＳ）,并结合氩离子溅射剥层,研究了非晶Ｎｉ１９Ｚｒ９Ａｌ７２合金条带的表面状态。结果表明,在条带表层,Ｎｉ以金属态存在,Ａｌ和Ｚｒ被选择氧化,且Ａｌ被优先选择氧化。条带两侧表面均被一薄层氧化物覆盖,氧化物的主要组分是Ａｌ２Ｏ３,另有少量的ＺｒＯ２．     

Studies on polymeric conservation treatments of ceramic tiles with Paraloid B‐72 and two alkoxysilanes

The aim of this study was to evaluate the effect of different polymeric protections applied on ceramic tiles on their mechanical and water absorption properties. Three conservation products were used: the acrylic polymer Paraloid B‐72 and two alkoxysilane‐based formulations (tetraethoxysilane (TEOS) and IN2210, a polidimetilsiloxane‐based formulation). The coatings were applied onto handmade tiles manufactured according to a 18th century procedure. Different application procedures (immersion, brushing, and spraying) were tested. The protection effectiveness was assessed through capillary water absorption and four point bending tests. The mineralogical characterization of tiles was undertaken by XRD. The best protective properties of the tiles were achieved by immersion treatments with Paraloid B‐72 based on the protocols followed by the museums restoration departments. Nevertheless, the results of the present work show that the second immersion in Paraloid B‐72 solution, commonly made, can be eliminated, as it does not provide any significant increase in the hydrophobic or mechanical properties of the tiles. As a result, there are obvious economical benefits, as the coating process became less time‐consuming and more environmental friendly, as the amount of organic compounds is reduced. On the other hand, the use of small volumes of Paraloid B‐72 solution applied by brush, or IN2210 sprayed can provide good results, if the only purpose of the treatment is the increase of the hydrophobic properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

ЦКБ—72型轴承试验机改造

利用现代计算机技术和传感器技术将ЦКБ—72轴承寿命试验机进行改造,以满足一般的轴承寿命试验及轴承特殊性能试验。改造后的试验机可自动检测并记录试验轴承的温度、载荷、转速等参数,实现试验机的智能化控制。     

升压型DC／DC变换器在便携式仪器仪表中的应用

介绍三种升压型DC／DC变换器QX2301、VA7910和XC6371的特点及其典型应用电路,可广泛用于电池供电的便携式仪器仪表中。