Inverted Solution Processable OLEDs Using a Metal Oxide as an Electron Injection Contact.

A new type of bottom‐emission electroluminescent device is described in which a metal oxide is used as the electron‐injecting contact. The preparation of such a device is simple. It consists of the deposition of a thin layer of a metal oxide on top of an indium tin oxide covered glass substrate, followed by the solution processing of the light‐emitting layer and subsequently the deposition of a high‐workfunction (air‐stable) metal anode. This architecture allows for a low‐cost electroluminescent device because no rigorous encapsulation is required. Electroluminescence with a high brightness reaching 5700 cd m^–2 is observed at voltages as low as 8 V, demonstrating the potential of this new approach to organic light‐emitting diode (OLED) devices. Unfortunately the device efficiency is rather low because of the high current density flowing through the device. We show that the device only operates after the insertion of an additional hole‐injection layer in between the light‐emitting polymer (LEP) and the metal anode. A simple model that explains the experimental results and provides avenues for further optimization of these devices is described. It is based on the idea that the barrier for electron injection is lowered by the formation of a space–charge field over the metal‐oxide–LEP interface due to the build up of holes in the LEP layer close to this interface.     

加氢处理润滑油基础油各组分对光安定性的影响

将经紫外光照前后的加氢处理润滑油基础油分离为饱和烃、轻质芳烃、中质芳烃、重质芳烃和极性组分，分别采用薄层色谱、质谱和紫外吸收光谱分析了各组分的烃组成、硫和氮含量的变化，并通过将从原料油中分离出的各组分反加到光安定性好的饱和烃中，试验验证了加氢处理润滑油基础油中的重质芳烃和极性组分是光不安定组分，其中含有硫、氮的芳香杂环化合物光安定性差。     

影响道路沥青低温抗裂性能的因素

用弯曲梁流变仪、直接拉伸试验机对7种国内外油源沥青样品进行了低温抗裂性能的评价，从沥青的四组分、相对分子质量及其分布来分析其对沥青低温抗裂性能的影响，结果表明，沥青的相对分子质量分布宽，对沥青的低温抗裂性能有利。     

液晶光阀光电导层光吸收系数的研究

用化学气相沉积法制备了液晶光阀中光电导层———非晶硅薄膜,从实验中得出最佳制备工艺的参数取值。给出了用包络线法测量非晶硅薄膜光吸收系数的原理,测量了样品的光吸收系数随波长的变化规律。得到样品在最佳工艺条件下的光吸收系数高于1×103cm-1。     

Distributed Optical Fiber Sensor for Multi-point Temperature Measurement

The distributed optical fiber sensing technology is overviewed, which is based on Raman scattering light theory. Basic operation principle, structure, system characteristics and signal processing are discussed. This structure and method of the signal processing possess of certain spatial resolution, hence will ensure the practicability of system.     

Application of piece‐wise linear weight functions for 2D 8‐node quadrilateral element in contact problems

The present study is a continuation of our previous work with the aim to reduce problems caused by standard higher order elements in contact problems. The difficulties can be attributed to the inherent property of the Galerkin method which gives uneven distributions of nodal forces resulting in oscillating contact pressures. The proposed remedy is use of piece‐wise linear weight functions. The methods to establish stiffness and/or mass matrix for 8‐node quadrilateral element in 2D are presented, i.e. the condensing and direct procedures. The energy and nodal displacement error norms are also checked to establish the convergence ratio. Interpretation of calculated contact pressures is discussed. Two new 2D 8‐node quadrilateral elements, QUAD8C and QUAD8D, are derived and tested in many examples, which show their good performance in contact problems. Copyright © 2004 John Wiley & Sons, Ltd.     

A simple approximation algorithm for the weighted matching problem

We present a linear time approximation algorithm with a performance ratio of 1/2 for finding a maximum weight matching in an arbitrary graph. Such a result is already known and is due to Preis [STACS'99, Lecture Notes in Comput. Sci., Vol. 1563, 1999, pp. 259-269]. Our algorithm uses a new approach which is much simpler than the one given by Preis and needs no amortized analysis for its running time.     

高分子量丙烯酰胺-DAC共聚物的研制

采用复合引发体系 ,以丙烯酰胺 (AM)和阳离子单体丙烯酰氧乙基三甲基氯化铵(DAC)为共聚体 ,进行水溶液绝热聚合 ,研制了一种DAC单体含量为 4 0 %～ 5 0 %、相对分子质量大于 1× 10 7的阳离子型聚丙烯酰胺。     

Pool boiling on a superhydrophilic surface

Titanium Dioxide, TiO₂, is a photocatalyst with a unique characteristic. A surface coated with TiO₂ exhibits an extremely high affinity for water when exposed to UV light and the contact angle decreases nearly to zero. Inversely, the contact angle increases when the surface is shielded from UV. This superhydrophilic nature gives a self-cleaning effect to the coated surface and has already been applied to some construction materials, car coatings and so on. We applied this property to the enhancement of boiling heat transfer. An experiment involving the pool boiling of pure water has been performed to make clear the effect of high wettability on heat transfer characteristics. The heat transfer surface is a vertical copper cylinder of 17 mm in diameter and the measurement has been done at saturated temperature and in a steady state. Both TiO₂-coated and non-coated surfaces were used for comparison. In the case of the TiO₂-coated surface, it is exposed to UV light for a few hours before experiment and it is found that the maximum heat flux (CHF) is about two times larger than that of the uncoated surface. The temperature at minimum heat flux (MHF) for the superhydrophilic surface is higher by 100 K than that for the normal one. The superhydrophilic surface can be an ideal heat transfer surface. Copyright © 2002 John Wiley & Sons, Ltd.