Packaging of a 128 by 128 liquid-crystal-on-silicon spatial lightmodulator using self-pulling soldering

A self-pulling soldering technology has been demonstrated for assembling liquid crystal on silicon (LCOS) spatial light modulators (SLMs). Solder joints with different profiles and sizes are designed to provide vertical surface tension forces to control the gap accommodating the ferroelectric liquid crystal (FLC) layer in the range of a micron with sub-micron uniformity. This technology provides an automatic, batch assembly process for a LCOS SLM through one reflow process. The component designs and process optimization are described, and the first operational results are presented     

The chemical and physical properties of electrochemically prepared polyaniline perchlorate (PAP)

Polyaniline perchlorate (PAP) was synthesized by electrochemical oxidation from 0.2 M aniline in acetonitrile solution containing 0.1 M tetraethylammonium perchlorate as supporting electrolyte. From polarographic and cyclic voltammetry results, the values of the half-wave potential (E_1/2), transfer coefficient (α), and number of electrons related to the electrode reaction (n) were calculated to be 825 mV, 0.894, and 1, respectively. The morphology of the PAP film was observed by using an SEM analyzer. From thermal analysis of the PAP sample, the reaction rate (R) for its thermal decomposition was obtained from the TGA result and a exothermic peak at 330°C was also observed in the DSC curve. The electrical conductivity of the PAP pellet was measured at temperatures from ?170 to 25°C. From a plot of conductivity vs. 1/T, the activation energy (E_a) was obtained to be 0.14 eV. The conduction mechanism in a pressed pellet of PAP is suggested to be electronic hopping conduction. The values of the ESR parameters were calculated from an ESR curve for PAP at room temperature.     

1.55 /spl mu/m bottom-emitting InAlGaAs VCSELs with Al/sub 2/O/sub 3//a-Si thin-film pairs as top mirror

A a 1.55 /spl mu/m InAlGaAs/InP vertical-cavity surface-emitting laser grown by metal-organic chemical vapour deposition is presented. Al/sub 2/O/sub 3//a-Si thin-film pairs and InAlGaAs/InAlAs epitaxial layers are used as a top mirror and a bottom-side output coupler, respectively. Direct modulation characteristics through singlemode fibre are reported at a speed of 2.5 Gbit/s.     

MICROBIAL DESULFURIZATION OF COAL

The sulfur found in coal is generally divided into three forms: pyritic, sulfate, and organic sulfur. Originating from irt-situ oxidation of metal sulfides, sulfates axe present in coal at low concentrations. Being soluble in water, they are relatively easy to be leached from the coal. Similarly, microbial depyritization promotes the oxidative conversion of inorganic sulfur compounds to water-soluble products. The pyrite removal results from the combined effects of direct bacterial attack and indirect chemical solubilization. In the former, pyrite (FeS₂) is oxidized by bacteria into Fe₂(SO4) ₃; in the latter, ferric iron is the actual oxidizing agent and microorganisms serve to regenerate the ferric iron from ferrous iron.

Organic sulfur is chemically bound to the carbon skeleton of coal. It is believed to be present mainly in the forms of organic sulfides, disulfides, thiols and thiophenes. Two pathways have been proposed for microbial desulfurization of heterocycles. One emphasized the oxidation of carbon ring structures to polar teachable derivatives. The other stressed the sulfur-specific metabolism without degradation of the carbon skeleton. Both pathways have been demonstrated with model organosulfur compounds, especially dibenzothiophene (DBT). Reports on organic sulfur removal from coal and water-soluble coal-derived products by microorganisms are also available. Unfortunately, due to the difficulty in accurate analysis.of organic sulfur content, the technical feasibility of microbial organic sulfur removal from coal is still in dispute.

The costs of independent microbial depyritization and organic:sulfur removal were estimated to be $10-14 and $14 per ton of coal, respectively. A cost analysis for a tow-step process, which was designed to achieve complete removal of inorganic sulfur and a 40% reduction of organic sulfur, yieded $11 per ton of coal. These are lower than the costs of other techniques, e.g. $20-40 per ton of coal for flue-gas desulfurization.     

纳米晶氧敏材料SrMgxTi1-xO3的制备与性能研究

应用硬脂酸法制备了纳米级晶粒大小的SrMgxTi1-xO3(x=0.1,0.2…0.5),采用DTA，TG，XRD，XPS等手段进行表征，结果表明，Mg部分取代了Ti进入了晶格中，生成了单一晶相的复合氧化物，掺杂了Mg之后的材料在所测量的氧浓度范围内，呈单一的P型导电特性，具有优良的敏性能，颗粒小，适应制成小型氧敏器件而获得实际应用。     

电厂中速磨煤机密封风机的选型设计

介绍密封风机的作用及工作过程,分析密封风机因选型不当可能出现的问题,并以徐塘电厂为例进行了风机选型设计。密封风机的正确选型不仅减小了磨煤机密封及内部受损,而且稳定了锅炉机组的工作。     

Quality factor measurement of micro gyroscope structure according to vacuum level and desired Q-factor range package method

A micro-machined gyro chip of gyroscope is normally packaged in specific vacuum level to get the specific quality factor(Q-factor). If the Q-factor is too high, frequency tuning and the approximate matching between driving and sensing comb structure become difficult, and if the Q-factor is too low, its sensitivity decreases. The optimum Q-factor of our gyro chip design is 4000 range. To get this range, we measured the drive mode Q-factor as vacuum level of our gyro chip and we found that the vacuum level of the desired Q-factor 4000 is in the range of 740 mTorr. Based on this data, we fabricate the wafer level package gyro chip of the desired Q-factor by controlled the basic pressure of package bonding chamber just prior to the bonding process. After wafer level package process, we measured Q-factor of whole samples. Among 804 samples, 502 packaged gyro chips are worked and the Q-factor of 67% samples is between 3500 and 4500 range.     

Ludesch的勘探人员旅馆

位于Ludesch的圣马丁勘探人员旅馆属于奥地利Vorarlberg的一种革新木结构作法的建筑。此建筑从外表看是个清晰的立方体，它建在与公路平行的地段边缘。这有利于建立明确的入口位置。同时，该建筑将后方的林区——不受打扰的勘探人员专用操场与公路隔离开来。     

大功率凝结水泵的变频调速技术改造

指出十里泉发电厂6#机组两台1000 kW定速凝结水泵运行存在的问题,介绍水泵变频调速改造的方案及应用情况,总结凝结水泵改造为变频调速后的运行效果和节能效果。