Polyetherimide substrates for future high density optical data storage

Polyetherimide (PEI) substrate for next‐generation high density optical data storage is fabricated and characterized. Cover‐layer incident or first‐surface recording configurations do not require optical properties of the substrate, which are the prerequisite conditions for the conventional material of polycarbonate (PC). Instead of the optical properties, good mechanical properties with a sufficient transcribability are required. Even though PEI has higher glass transition temperature than that of PC, a microscopic transcribability of PEI is comparable with PC by laminating a thermal insulation layer on the backside of a stamper to retard the heat flow. A macroscopic warpage of PEI substrate is smaller than that of PC substrates, which reduces tilt and servo burden. The lowest critical speed coupled with the flutter of PEI substrate is larger than that of PC substrate because of the mechanical properties of PEI. POLYM. ENG. SCI., 48:97–101, 2008. © 2007 Society of Plastics Engineers     

基于USB的155 Mb/s码型发生器的研制

介绍了一种带USB接口的光的155Mb／s码型发生器。伪随机码和其他格式的码型由PC产生通过USB接口进入双口RAM，再经串并变换后由光发射模块发射。该系统可方便地设定各种格式的码型，并同时具备光接口和电接口，可广泛应用于光通信各种实验中，具有重要的实用价值。     

Growth of highly orientated strontium barium niobate thin films on Si substrates through the sol–gel process using a K: SBN template layer

We report the growth of highly C-axis orientation of Sr _x Ba_1−x Nb₂O₆ (SBN) thin films on p-type (100) Si substrates by using a potassium-substituted SBN template layer with the sol–gel method. The crystallization of SBN thin films was found closely related to the potassium ion doping concentration and the postannealing temperature of the K-SBN template layer. Secondary ion mass spectrometry analysis showed that potassium elements were accumulated at the interface of the template layer and silicon substrate. SBN films postannealed at 750 °C with K-SBN template layer has a smaller full width at half maximum of X-ray rocking curve of 2.45° than that of 5.40° for the pure SBN films. By introducing a template layer, the surface morphologies of SBN films fabricated on silicon substrate were greatly improved.     

Formation mechanism of 21R AlN-polytypoids in aluminothermic reduction and nitridation process

Synthesis of 21R AlN polytypoids was investigated using Al and ultrafine SiO₂ powder in a flowing nitrogen atmosphere by means of thermal gravity (TG), differential scanning calorimeter (DSC), X-ray diffractometer (XRD) and scanning electronic microscope (SEM) linked with energy dispersive spectrometer (EDS). The results showed that the formation mechanism of AlN polytypoids was different from that in reaction sintering process using Si₃N₄, AlN, Al₂O₃ and other sintering additive as raw materials. It was suggested that firstly Al reduce SiO₂ into Si and is also nitrided into AlN, then AlN, Al₂O₃ and SiO₂ dissolve into silicon liquid until the AlN polytypoids precipitate in saturated liquid in a flowing nitrogen atmosphere at lower than 1700 °C.     

A Nonvolatile Organic Memory Device Using ITO Surfaces Modified by Ag‐Nanodots

We report on a single‐layer organic memory device made of poly(N‐vinylcarbazole) embedded between an Al electrode and ITO modified with Ag nanodots (Ag‐NDs). Devices exhibit high ON/OFF switching ratios of 10⁴. This level of performance could be achieved by modifying the ITO electrodes with some Ag‐NDs that act as trapping sites, reducing the current in the OFF state. Temperature dependence of the electrical characteristics suggest that the current of the low‐resistance state can be attributed to Schottky charge tunnelling through low‐resistance pathways of Al particles in the polymer layer and that the high‐resistance state can be controlled by charge trapping by the Al particles and Ag‐NDs.     

Complementary effects of solid lubricants in the automotive brake lining

An experimental investigation was carried out to examine the tribological behavior of NAO (non-asbestos organic) type brake linings containing different volume ratios of graphite and antimony trisulfide (Sb₂S₃). A scale dynamometer was used for friction tests and particular emphases were given to the effect of applied pressure, sliding speed, and temperature on the coefficient of friction according to the relative amounts of the two solid lubricants. Results showed that the brake linings with both solid lubricants exhibited better friction stability and less speed sensitivity than the friction materials containing a single solid lubricant. In particular, the brake lining containing higher concentrations of graphite showed better fade resistance than others during high-temperature friction test.     

储层压力与天然气分布关系——以鄂北塔巴庙地区上古生界储层为例

通过分析塔巴庙地区储层压力的分布特征，建立了研究区泥岩压实曲线，并对影响和控制该区储层压力的主要因素和机理进行了探讨，对“欠压实”剩余压力、生气增压、抬升引起的降压进行了定量计算。分析结果表明，晚三叠-早白垩世末“欠压实”作用和晚侏罗-早白垩世末烃源岩大量生烃作用使塔巴庙地区上古生界形成异常高压；晚白垩系构造抬升降压，使得现今储层为正常-低异常压力。同时证实了“欠压实”对天然气有压力封盖作用，天然气都分布在最大“欠压实”幅度以下的储层当中。烃源岩生气高峰为晚侏罗-早白垩世末，但天然气大规模运移是在晚白垩世，方向以沿过剩压力梯度降低较快的方向（太原-山西组至下石盒子组）垂向运移，通道主要为裂缝，运移的动力主要为异常高压。由于储层致密，聚集成藏能量有限，造成天然气充注不足、气水分异不好、含气饱和度低。     

Synthesis of Mg-α-sialon from the mixture of silicon, aluminum and magnesia powders in a flowing nitrogen atmosphere

Synthesis of Mg-α-Sialon has been investigated by the mixture of silicon, aluminum and magnesia powders in a flowing nitrogen atmosphere in the range of 1300–1600 °C, when Mg-α-Sialon is designed with a chemical formulation of Mg _x Si_12−3x Al_3x O _x N_16−x in present work. The results showed that Mg-α-sialon initially occurred at 1400 °C and basically increased with elevated temperatures. For the samples of x = 0.6, 0.8 and 1.0 the products mainly consisted of Mg-α-Sialon with small amounts of Si, AlN and 21R AlN-polytypoid phases at 1600° C. However, in final products of x = 1.2, 1.4 and 1.6 only a little of Mg-α-Sialon formed and a great amount of Si remained in these samples at all the fired temperatures. Fortunately, the content of Mg-α-Sialon in these samples were obviously increased by adding a small amount of α-Si₃N₄ as seeds before nitridation.     

A Study on NMR and GC/MS Spectra of the Isomers of Linear Hexyl Naphthalene

The GC/MS and NMR analysis of the reaction products of naphthalene with 1-bromohexane were reported. The products obtained were suggested to have six isomers of linear hexylnaphthalene and the structure of each isomer was determined by GC/MS and NMR spectra. For the first time, the unique chemical shift data were obtained. The content of each isomer calculated by ¹H NMR and ¹³C NMR spectra was consistent with that by GC/MS spectra, which confirmed the accuracy of NMR data.     

Automating application software generation

Many approaches have been proposed to enhance software productivity and reliability. These approaches typically fall into three categories: the engineering approach, the formal approach and the knowledge-based approach. But the optimal gain in software productivity cannot be obtained if one relies on only one of these approaches. This paper describes the work in knowledge-based software engineering conducted by the authors for the past 10 years. The final goal of the research is to develop a paradigm for software engineering which integrates the three approaches mentioned above. A knowledge-based tool which can support the whole process of software development is provided in this paper.