磷酸锌铝分子筛ZAPO-5晶体的合成及表征

用水热晶化法以三乙醇胺为模板剂合成了磷酸锌铝分子筛ZAPO-5微晶,以二乙氨基乙醇为模板剂合成了长178μm的优质磷酸锌铝分子筛ZAPO-5大单晶。经IR,SEM和XRD表征ZAPO-5具有AlPO4-5型分子筛结构。     

90 GW peak power few-cycle mid-infrared pulses from an optical parametric amplifier

We demonstrate a compact 20 Hz repetition-rate mid-IR OPCPA system operating at a central wavelength of 3900 nm with the tail-to-tail spectrum extending over 600 nm and delivering 8 mJ pulses that are compressed to 83 fs (<7 optical cycles). Because of the long optical period (～13 fs) and a high peak power, the system opens a range of unprecedented opportunities for tabletop ultrafast science and is particularly attractive as a driver for a highly efficient generation of ultrafast coherent x-ray continua for biomolecular and element specific imaging.     

风电叶片气动外形设计对质量的影响

随着大型风电叶片长度的增加,质量因素对叶片的结构特性影响越来越大。要求在保证必要的气动效率条件下降低叶片的质量。本文利用简化后的风电叶片质量求解模型,分析了叶片铺层规律基本不变,挥舞刚度固定等条件下,叶片的弦长、厚度及相对厚度对叶片质量的影响。结果表明:增加叶片的厚度有利于减小叶片质量,对于所分析的叶片,在叶片展向20%~80%的增加相对厚度对减小质量最有利。在此条件下,考虑到气动与质量的耦合影响,降低叶片质量将导致气动效率的损失。     

Cascade Two-photon Correlated-emission Optical Bistability

１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｅｓｔｕｄｉｅｓｏｆｔｈｅｇｅｎｅｒａｔｉｏｎｏｆｔｈｅｓｑｕｅｚｅｄｓｔａｔｅｓｏｆｌｉｇｈｔａｎｄｔｈｅｉｒｐｒｏｐｅｒｔｉｅｓ，ｔｗｏｐｈｏｔｏｎｔｒａｎｓｉｔｉｏｎｐｒｏｃｅｓｅｓｈａｖｅｒｅｃｉｅｖｅｄｇ...     

Surfactant effects of chlorpromazine and imipramine on lipid bilayers containing sphingomyelin and cholesterol

The surface-active drugs chlorpromazine (CPZ) and imipramine (IP) have been tested on large unilamellar vesicles composed of phosphatidylcholine (PC), sphingomyelin (SM), and cholesterol (Ch) in different proportions. The well-characterized nonionic detergent Triton X-100 (TX) has also been used in parallel experiments. Leakage of vesicular aqueous contents and bilayer solubilization have been measured for each surfactant molecule and vesicle composition. All three surface-active molecules behave in a qualitatively similar way, irrespective of bilayer composition: they induce leakage at concentrations well below their critical micellar concentrations (cmc) and solubilization near the cmc. In these events, the potency of the three surfactants under study increases with decreasing cmc, in the order IP相似文献   

Synthesis and Characterization of a Novel Addition-Fragmentation Reactive Surfactant (TRANSURF) for Use in Free-Radical Emulsion Polymerizations

The synthesis and characterization of a new type of chain-transfer-active surfactant (i.e., TRANSURF) is reported. The compound was designed on the basis of the chemistry of macromers, which undergo free-radical chain-transfer addition-fragmentation reactions. In effect this allows incorporation of the surfactant molecule into the polymer backbone, and thus reduces the influence of surfactant migration during film formation. Surfactants of this type, containing two hydrophilic head groups, can have a marked influence on the polymer and latex properties (e.g., molecular weight distributions and particle size). Characterization of the physical properties of this surfactant was therefore carried out using surface tension, conductivity, and fluorescence techniques. Because of the surfactant's unusual "bolaform" (alpha, omega) (Zana, R., in "Structure-Performance Relationships in Surfactants" (K. Esumi and M. Ueno, Eds.), Surfactant Science Series 70, Dekker, New York, 1997) structure the micelle formation process has been found to be quite different from that of the conventional surfactant, sodium dodecyl sulfate (SDS). From the surface tension data a flat molecular conformation was evident at 1x10(-3) mol dm(-3) (131 ?(2) surface area), which we assumed to correspond to the low aggregation number of premicellar aggregates. There is evidence to suggest formation of a larger volume of the microdomains in these micelles compared to that in SDS. At higher TRANSURF concentrations, however, we find no clear indication of a switch to a "wicket"-type conformation, although such conformational changes cannot be ruled out. Copyright 2001 Academic Press.     

表面修饰的硫化镉纳米粒子与牛血清白蛋白相互作用的荧光光谱研究

由于半导体纳米晶体独特的物理和化学特性,具有优良的光谱特征和光化学稳定性,其作为荧光生物探针,在生物学、医学方面的学术价值和良好的发展前景正引起科学工作者的广泛关注[1～3].