A Study of the Constituents of the Bark of Chamaecyparis Formosensis Matsum

Sixteen compounds were isolated from the bark of Chamaecyparis formosensis Matsum. These compounds include four categories: (a) long-chain alcohols, acids and esters, (b) sterols and their glucosides, (c) o-methoxyphenol and related compounds, (d) diterpenes of abietane, pimarane, secoabietane and totarane.     

The effects of melt annealing and counterpart's molecular weight on the thermal properties and phase morphology of poly(L‐lactide)‐based blends

The thermal properties and phase morphology of poly(L ‐lactide) (PLLA)‐based blends have been studied. Two poly(ethylene glycol)s (PEGs) with molecular weight (MW) of about 1,500 (1.5k) g/mol and 2,000,000 (2M) g/mol, respectively, were used as counterparts. The blends were annealed at a preselected temperature of 200 °C for either 2 min or 30 min before the characterizations. Both PEGs were determined to enhance the crystallizability of PLLA. After a 2‐min process of annealing, the PEG(1.5k)'s crystallization efficiency on PLLA has been noted to increase with the increase of its content. Conversely, PEG(2M)'s crystallization efficiency declined with the increase of its content. Extending the annealing time has evidently changed the PEGs' crystallization effect on PLLA. Moreover, the PEG(1.5k) has, to a greater extent, brought about the depression of PLLA's melting temperature by increasing its content, and this depression increased with the annealing time. The blends exhibited lower thermal stability than those of the parent components, particularly for the PEG(1.5k)‐included system with a higher PEG content. Regardless of the annealing time, the PEG(1.5k)‐included blends have shown homogeneous melt morphology under light microscope, whereas the PEG(2M)‐included blends have displayed phase‐separated melt morphology. In addition to the composition, PEG's MW and annealing time influence the crystalline morphology of the blends. The ringed PLLA spherulites have appeared mostly in the 2‐min annealed PEG(1.5k)‐included blends. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1497–1510, 2009     

Metallocene bis(perfluoroalkanesulfonate)s as air-stable cationic Lewis acids

Zirconocene and titanocene bis(perfluorooctanesulfonate)s were synthesized. In contrast to the corresponding triflates and perchlorates, these compounds are air- and water-stable. They were proved to be ionic on the basis of conductivity measurements and X-ray analysis, allowing these complexes to be stored for months. The strong Lewis acidity of these cationic metallocene species, which was proved by ESR study, enabled catalytic glycosylation.     

（K1（x），K2（x））-有限伸张映射

该文首先给出(K1(x),K2(x))一有限伸张映射的定义,然后研究其自我提高的可积性性质.最后利用Caccioppoli型不等式得到可去奇异性结果.     

Nanomechanical characteristics of SnO2:F thin films deposited by chemical vapor deposition

The nanoindentation characterizations and mechanical properties of fluorine-doped tin oxide (SnO₂:F) films deposited on glass substrates, using chemical vapor deposition (CVD) method, were studied, which included the effects of the indentation loads, the loading time and the hold time on the thin film. The surface roughness, fractal dimension and frictional coefficient were also studied by varying the freon flow rates. X-ray diffraction (XRD), atomic force microscopy (AFM) and frictional force microscopy (FFM) were used to analyze the morphology of the microstructure. The results showed that crystalline structure of the film had a high intensity (1 1 0) peak orientation, especially at a low freon flow rate. According to the nanoindentation records, the Young's modulus ranged from 62.4 to 75.1 GPa and the hardness ranged from 5.1 to 9.9 GPa at a freon flow rate of 8000 sccm. The changes in measured properties were due to changing loading rate.     

Parseval Theory of Complex Wavelet Transform for Wavelet Family Including Rotational Parameters

A rotational parameter Rθ has been introduced to complex wavelet transform （CWT）. The rotational CWT （RCWT） corresponds to a matrix element 〈φ｜U2（θ;μ;κ）[F〉 in the context of quantum mechanics, where U2（θ;μ;κ） is a two-mode rotational displacing-squeezing operator in the 〈η｜ representation. Based on this, the Parseval theorem and the inversion formula of RCWT have been proved. The concise proof not only manifestly shows the merit of Dirac＇s representation theory but also leads to a new orthogonal property of complex mother wavelets in parameter space.     

A Novel Rule Induction Algorithm

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｋｎｏｗｌｅｄｇｅｄｉｓｃｏｖｅｒｙｉｎｄａｔａｂａｓｅｓ (ＫＤＤ)ｉｓｃｏｎｃｅｒｎｅｄｗｉｔｈｅｘｔｒａｃｔｉｎｇｕｓｅｆｕｌｉｎｆｏｒｍａｔｉｏｎｆｒｏｍｄａｔａｂａｓｅｓ.Ｔｈｅｔｅｒｍｄａｔａｍｉｎｉｎｇｈａｓｈｉｓｔｏｒｉｃａｌｌｙｂｅｅｎｕｓｅｄｉｎｔｈｅｄａｔａｂａｓｅｃｏｍｍｕｎｉｔｙａｎｄｉｎｓｔａｔｉｓｔｉｃｓ (ｏｆｔｅｎｉｎｔｈｅｌａｔｔｅｒｗｉｔｈｎｅｇａｔｉｖｅｃｏｎｎｏｔａｔｉｏｎｓｔｏｉｎｄｉｃａｔｅｉｍｐｒｏｐｅｒｄａｔａａｎａｌｙ…     

Control of the microstructure of polymer network and effects of the microstructures on light scattering properties of UV‐cured polymer‐dispersed liquid crystal films

Polymer‐dispersed liquid crystals (PDLC) films were prepared from ultraviolet (UV) irradiation‐induced polymerization of the photopolymerizable monomers in photopolymerizable monomers/nematic liquid crystal (LC) mixtures. The effects of the composition of the mixtures, the curing temperature, and the UV light intensity on the microstructure of the polymer network in the PDLC films were investigated. Furthermore, the effects of the microstructures on the light scattering properties of the PDLC films in the wavelength region of 300–2500 nm were studied experimentally and theoretically based on the combination of three kinds of classical light scattering theories: the Rayleigh‐Gans (RG) approach, the anomalous diffraction (AD) approach, and the geometrical optics (GO) approach. It was found that the sizes of LC domain in PDLC films increased with the increase of the LC content as well as the decrease of the UV curing intensity, while increased at first and then decreased with the increase of the curing temperature. Moreover, smaller LC domain sizes could exhibit strong scattering properties in a smaller VIS wavelength region and the transmittance in NIR region (especially in the wavelength range of 1300–2500 nm) obviously decreased with the increasing sizes of LC domain. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2090–2099, 2008