Modulation of Spin-Crossover Behavior in an Elongated and Flexible Hofmann-Type Porous Coordination Polymer

Three porous coordination polymers {Fe(dpa)[Pt(CN)₄]·G·nH₂O} (1-G; dpa = 1,2-di(4-pyridyl)ethane, G = dpa, bibenzyl (bbz) and stilbene (stb)) have been prepared by using a long and flexible ligand dpa. These compounds formed analogous 3-D elongated Hofmann-type frameworks based on 2-D planar layers extended by Pt–CN–Fe linkages with dpa as flexible pillar ligands. 1-dpa showed a characteristic three-step spin transition (ST) in the temperature range 180–240 K. The ST behavior was reversibly modulated by dehydration and hydration processes in keeping with the three steps. 1-bbz and 1-stb exhibited a gradual three-step ST over the range 80–200 K and an abrupt ST with T _c = 163 K. The guest-dependent cooperativity of the ST behavior is discussed by considering the flexibility of the framework and guest molecules.     

Thermophilic phospholipase A2 in the cytosolic fraction from the archaeon Pyrococcus horikoshii

Hyperthermophilic archaeon Pyrococcus horikoshii produced phospholipase A² in a cytosolic fraction. The enzyme displayed optimal activity at 90°C and pH 7 and preferentially hydrolyzed sn-2 fatty acids in the following order: linoleoyl> oleoyl>arachidoyl phosphatidylcholine. Phospholipase A₂ had similar activities toward l-α-1-palmitoyl-2-arachidoyl derivatives of phosphatidylcholine and phosphatidylethanolamine. Phospholipase A₂ activity was unaffected by the addition of 0.0001–1 mM calcium, but was inhibited slightly by the addition of 2–10 mM calcium. The activity was enhanced more than 5–18-fold in the presence of 3–20% (vol/vol) glycerol. The activity was unaffected by the addition of 1–5 mM EDTA or 0.01–20 mM dithiothreitol. A caldarchaetidic acid derivative having a molecular weight of 1544 disappeared upon incubation of the cytosolic fraction with total lipid. The phospholipase A₂ was difficult to purify by general chromatography because it existed as an aggregate. Electrophoresis was carried out using 10–15% polyacrylamide gels containing sodium dodecyl sulfate (SDS-PAGE). No activity of phospholipase A₂ activity was observed in the absence of proteins less than 19 kD in size, as fractionated by SDS-PAGE. Portions of this article were presented at the Biocatalysis Symposium at the 91st Annual Meeting and Expo of the American Oil Chemists’ Society in San Diego, CA, April, 2000.     

Single- and double-layered mesoporous TiO2/P25 TiO2 electrode for dye-sensitized solar cell

Nanocrystalline mesoporous titania (MP-TiO₂) was synthesized by surfactant-assisted templating method using tetraisopropyl orthotitanate modified with acetylacetone and laurylamine hydrochloride as template. The short-circuit photocurrent density (J_sc) of the cell made from MP-TiO₂ was much higher than that of the cell made from commercial P25 titania. The incident photon to current conversion efficiency (IPCE) spectra of thin MP-TiO₂ cell were higher than that of thick P25 cell in the region between 400 and 475 nm but lower than that of thick P25 cell in the red region, because the thickness of thin transparent MP-TiO₂ film was not enough to scatter the light leading to low absorbed spectra in red region. IPCE spectra of MP-TiO₂ can be improved by using the cell made from blended MP-TiO₂ with P25. The cell performance was improved with increasing sintering temperature. Double-layered titania cells were also fabricated to further improve the cell performance by increasing light scattering and amount of adsorbed dye. The solar energy conversion efficiency (η) up to 8.1% was obtained by using the double-layered titania cell sintered at 450 °C for 2 h.     

A High-Speed Measurement Method for Reflective Liquid Crystal Cells Using a Liquid Crystal Polarization-Converting Device

We propose a novel measurement method for determining cell parameters, such as a cell thickness and twist angle in reflective liquid crystal (LC) cells, by using a unique polarization-converting device prepared with a circularly and homogeneously aligned LC (CH-LC) cell. The light intensity distributions from the reflective LC cell transmitted twice through the CH-LC cell are measured by a charge-coupled device array camera. Cell thickness can be derived by using coordinate values of local minimum spot in the spatial light intensity distribution measured at one wavelength, where the pretilt angle is assumed to be the designed value. Both cell thickness and twist angle can also be determined by two local minimum positions of the light intensity at two different wavelengths and the effects of a quarter-wave plate are discussed     

数字高清等离子电视图像质量技术的发展

随着数字广播服务的展开及数字通用光盘（DVD）普及，对具有高画质的平面、薄型电视的需求正在增长。我们已经开发了一种新的数字高清等离子电视来满足这种需求。这一新产品具有一个改善图像质量的系统，可以显示362亿种彩色以及最大2048级灰度的图像。该新系统与创新的彩色生成技术结合可以创造出生动的图像，其独有的运动图案降噪技术可以消除大部分持续困扰等离子屏（PDP）电视的运动图像畸形和赝像。这一技术使得在降低10％功耗的同时增加10％的亮度成为可能。     

Test Compression for IP Core Testing with Reconfigurable Network and Fixing-Flipping Coding

This paper proposes a class of test compression for IP (intellectual property) core testing. The proposed compression requires only test cubes for the IP cores and it dose not require the structural information about the IP cores. It uses both a reconfigurable network and classes of coding, namely fixing-flipping coding and fixing-shifting-flipping coding. The proposed compression is evaluated from the viewpoint of compression rates and hardware overhead. For three out of four large ISCAS89 benchmark circuits, the compression rates of the proposed compression are better than those of the four existing test compressions.

晶圆干燥缺陷的机理与控制

长期以来,人们对于硅片在经过HF湿法处理之后出现的水印早已有所认识,尤其是图形包含亲水和疏水层时最为明显。我们系统地研究了经过HF后道处理之缺陷形成的机理,并确认了与先前报道的水印截然不同的缺陷类型。根据X射线和其它分析表明,认为这些缺陷与周围环境残余的汽相HF和随后的晶圆表面反应有关。根据反应腔室HF浓度的不同可以产生不同类型的缺陷。由于水印是由硅在水中的氧化和随后产生的氧化物的分解形成的,少量的HF具有加速这个过程的效果。形成不同缺陷的条件,还有避免这些缺陷的策略均得以认定。正确的排空管理是一个关键的因素。最后发现,重参杂的硅更易产生缺陷。     

Photonic crystal microcrystalline silicon solar cells

Enhancing the absorption of thin‐film microcrystalline silicon solar cells over a broadband range in order to improve the energy conversion efficiency is a very important challenge in the development of low cost and stable solar energy harvesting. Here, we demonstrate that a broadband enhancement of the absorption can be achieved by creating a large number of resonant modes associated with two‐dimensional photonic crystal band edges. We utilize higher‐order optical modes perpendicular to the silicon layer, as well as the band‐folding effect by employing photonic crystal superlattice structures. We establish a method to incorporate photonic crystal structures into thin‐film (~500 nm) microcrystalline silicon photovoltaic layers while suppressing undesired defects formed in the microcrystalline silicon. The fabricated solar cells exhibit 1.3 times increase of a short circuit current density (from 15.0 mA/cm² to 19.6 mA/cm²) by introducing the photonic crystal structure, and consequently the conversion efficiency increases from 5.6% to 6.8%. Moreover, we theoretically analyze the absorption characteristics in the fabricated cell structure, and reveal that the energy conversion efficiency can be increased beyond 9.5% in a structure less than 1/400 as thick as conventional crystalline silicon solar cells with an efficiency of 24%. © 2015 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.     

Integrated CNTs thin film for MEMS mechanical sensors

This paper reports the top-down fabrication of CNTs thin film on MEMS structure, and characterization of piezoresistive coefficients of aligned single wall carbon nanotube (SWNT) forest film. The film was synthesized by water-assisted chemical vapor deposition (CVD), a process known as “super growth”. CNTs film was condensed, manually maneuvered and conveniently patterned by EB lithography to form desirable shapes. The longitudinal and transverse gauge factors of the CNTs thin film were measured to be 3.75 and 0.67, respectively.     

Distribution of microorganisms with particular reference to encapsulated bacteria in kefir grains

Propagable and non-propagable kefir grains in a form resembling cauliflower florets were observed by scanning electron microscopy (SEM) and light microscopy. In propagable grains short and long rod-shaped bacteria and yeasts formed separate colonies on the outside surface and inside. Internally, filaments which derived from capsules around the cells extended radially from a population of long rod-shaped bacteria. In non-propagable grains long rod-shaped bacteria with filamentous appendages were not observed, but only short rod-shaped bacteria and yeasts. Indian ink preparations showed presence of encapsulated bacteria in propagable grains and absence of these in non-propagable ones. The above results suggest that encapsulated bacteria are responsible for propagation of kefir grains.