传感器网络中基于二元簇的节能路由算法

传感器网络中的分簇算法已经被证明能够有效地节约能量。据此提出了一种基于二元簇的路由算法,其基本思想是网络中的每个节点同时属于2个不同簇,利用二元性来减少在路由发现中的资源浪费,并能够更加确定地发现路由以节约资源。理论分析和模拟实验都表明,该算法在能量消耗和网络生命周期延长方面较优。     

量子阱红外探测器能带结构的计算

利用电子波在阱与垒的界面上的反射及干涉效应，计算了量子阱红外探测器(QWIP)的能带结构，并对其适用性进行了分析和讨论。通过与K-P模型比较发现，本方法对计算较宽势阱(阱宽大于4nm)的量子阱结构的电子态适合。在垒宽和阱宽不变条件下，用两种方法计算得到的AlGaAs／GaAs量子阱材料中Al组分x与吸收峰值波长λp的关系曲线基本相同。结果说明，在较宽的范围内，本方法对QWIP能带结构的计算是适用且简便的。     

低发射率材料红外法向发射率谱测量方法的研究

采用热管技术研制了材料发射率谱的专用测量附件;利用双温测量技术,在P-E983型红外分光光度计及3600型数据站上进行了较低温度下低发射率材料红外法向发射率谱测量方法的研究.实测了几种材料的发射率谱;讨论了影响测量误差的诸因素.     

Linked influence of pH and cations on fatty-acid monolayer integrity related to high-quality Langmuir-Blodgett films

This study shows the connection between the morphological structure of transferred films and the chemical composition of the monolayer before transfer. The stability of a behenic acid monolayer depends on the linked influence of the type of cation and of the pH value in the aqueous subphase. The stability of the monolayer is assessed by the expansion of the solid-packed state and by the relaxation time. Its integrity is characterized by the number of crystal defects which appear in transferred Langmuir-Blodgett (LB) films as seen through Nomarski microscope observations. Both stability and integrity are greatly improved when Cd²⁺ or Mn²⁺are added to the subphase at pH 5.75 and 6 respectively. In these conditions, the transfer is very efficient and the LB films thus obtained are of very high quality. The pH values of the subphase at which the molecules of behenic acid are transformed into bivalent salts differ significantly according to the nature of the cation involved. Comparing infrared spectra of the LB films, it appeared that the relative amount of acid/salt found in the monolayer was practically the same with a subphase containing either Cd²⁺ at pH 5.75 or Mn²⁺ at pH 6. This suggests that the ratio of acidic and salt forms would be a key parameter for obtaining high-quality LB films.     

Use of pyrogenic silicas for petroleum oil polar fraction characterisation. Fourier transform infrared spectroscopy and microelectrophoresis studies

In the power transformer, the presence of polar or charged species in the insulating oil can cause failure and electric discharges. Solid substrates such as silica can be used to extract the polar species and to refine the oil in order to prevent future failure in the power transformer. However, the use of silica for petroleum oil separation and refining will depend on the silica characteristics such as surface charge, surface composition, specific surface area and particle size.Various pyrogenic silicas having various specific surface areas (49-200 m² g⁻¹) and particle sizes (207-500 nm) were used to extract the polar fractions from the neat transformer insulating oils (a new, NO, and used, UO2, oils). The oil covered silica samples were investigated by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy in the range 4000-600 cm⁻¹. The bare silica surfaces present two main hydroxyl components, a sharper peak at 3745 cm⁻¹, I₃₇₄₅, due to isolated silanols and a second broad, which spreads over 3745-3000 cm⁻¹, I_3745-3000, due to H-bonded silanols. The relative intensities of the two components, I₃₇₄₅/I_3745-3000, varied for the bare and the oil covered silicas depending on the solid surface characteristics. The adsorption of the NO polar fraction onto silica leads to strong reduction in intensity of the sharper peak in favour of the broad one. However, the adsorption of the UO2 polar fraction onto silica leads in all cases to the decrease in the intensity of the both silica OH components. Further, the UO2 adsorption on the silica leads to the apparition of a broad peak at low frequency in the region 3250-3300 cm⁻¹ which, is due to the associated phenolic groups of UO2 oil polar fraction. The analysis of the DRIFT spectra for various samples indicates that the oil polar fraction resembles to asphaltenes compounds.The microelectrophoresis method used to investigate the surface charge at the water/oil polar fraction covered silica interface, indicates negatively charged particles. Further, the negative charge increased with the pH, as resulting from the increase of the ionisation and/or the amount of the oil polar carboxylic and phenolic groups. The oil polar fraction, i.e. the asphaltene components, in contact with both the silica surface and water at high pH values rearrange, due to their amphiphilic character.Finally, the use of the silica substrates seems to be suited to extract and analyse polar species present in petroleum oil. A correlation is found between the nature of the oil, its functionalities, and the magnitude of its zeta potential value at the water/oil covered silica interface.     

Instability of zeolite Y supported cobalt sulfide hydrotreating catalysts in the absence of H2S

Ion exchanged CoNaY was sulfided at 473 and 673 K and subsequently heated in He at 673 and 773 K. The resulting samples were characterized by means of overall sulfur analysis, temperature programmed Ar treatment and Fourier transform infrared spectroscopy. It was shown that during He flushing at sufficiently high temperature a protolysis reaction occurs resulting in the decomposition of Co sulfide into Co²⁺ ions and H₂S.     

Modified Imidazoles: Degradation Inhibitors and Adhesion Promoters for Polyimide Films on Copper Substrates

Polyimide films on copper substrates that are exposed to elevated temperatures and an oxidizing environment will be subject to degradation. In order to halt this degradation without changing the properties of the system, a polymeric agent could be placed between the polyimide and the copper. This paper will investigate three such materials that will not only slow down the degradation of the polyimide and the oxidation of the copper, but will also improve adhesion within the system. Fourier transform infrared reflection-absorption spectroscopy (FTIR-RAS) will be used to investigate the polyimide/polymeric agent/copper system.     

Inductive proximity sensor with a flat coil and a new differential relaxation oscillator

A high-sensitivity flat-coil inductive proximity sensor microsystem has been realized and successfully tested. The flat coil, made with CMOS-compatible post processes, is connected to a versatile differential relaxation oscillator electronic interface. In this new and simple interface, the excitation, the signal extraction and amplification are assured by only one operational amplifier. Experimental results on the microsystem confirm that large output frequency variations occur when a metallic target approaches the sensor.     

CCD应用中的高速图象数据采集技术

介绍了一种可用于精密光学测量的高速线阵ＣＣＤ图象数据采集系统，给出了系统组成、各单元设计考虑和主要技术指标。