The MTV experiment: searching for T-violation in polarized Li-8 at TRIUMF

The MTV experiment (Mott Polarimetry for T-Violation Experiment) is running at TRIUMF, to search for a large T-violating transverse electron-polarization in polarized ⁸Li β-decay. We aim at reaching precision of 10^?4 for the R-correlation, which is defined as a T-violating triple vector correlation in the β-decay rate function. A Mott polarimeter system using a CDC (Cylindrical Drift Chamber) is used to measure the left-right scattering asymmetry in the Mott scattering from a thin metal foil. In the present study, we aim to discuss systematic effects in Mott polarimetry using the CDC.     

基于特征散度的模糊彩色图像分割算法

为提高算法的普适能力,提出了一种新的基于特征散度的模糊彩色图像分割算法(FDCIS).算法引入了特征散度和模糊相异性函数来度量差异性,利用特征散度进行数据聚类,实现图像的区域融合.实验证明,算法较好地降低了彩色图像大样本数据的运算量,简单而有效地解决了过度分割现象,避免了聚类算法对初始条件的依赖性,与人的主观视觉感知具有良好的一致性.     

Five Stilbene Glucosides from Gnetum gnemonoides and Gnetum africanum

Five new stilbene glucosides, gnemonosides F, G, H, I, and J were isolated from the stem lianas of Gnetum gnemonoides Brongn and Gnetum africanum Welw along with nine known stilbenoids. The structures of the new compounds were elucidated as gnetin E 4a,4b,4c‐O‐β‐triglucopyranoside ( 2 ), gnetin E 4a,4c‐O‐β‐diglucopyranoside ( 3 ), gnetin C 4a,4b,11a‐O‐β‐triglucopyranoside ( 4 ), gnetin D 4a,4b‐O‐β‐diglucopyranoside ( 5 ), and gnetuhainin A 4a,4b‐O‐β‐diglucopyranoside ( 6 ) on the basis of spectroscopic evidence.     

Syntheses and properties of a series of amphiphilic polyacrylamides bearing two long alkyl chains and phosphatidylcholine analogous groups in the side chains

A novel vinyl monomer 2-{(3-acrylamidopropyl)dimethyl ammonio}ethyl 2′-isopropyl phosphate (AAPI) having phosphatidylcholine analogous moiety and a series of new acrylamide monomers containing two long alkyl chains [stearyloleylacrylamide (SOAAm), distearylacrylamide (SSAAm), and n-docosyloleylacrylamide (DOAAm)] were synthesized and characterized. The polyacrylamides ( Va, Vb , and Vc ) were obtained from radical copolymerization of SOAAm, SSAAm, or DOAAm with AAPI in the presence of AIBN as an initiator. The investigations of these copolymers were carried out by x-ray analysis method, DSC, TG-DTA, and viscosity measurement, respectively. The copolymer Vb containing distearyl groups as hydrophobic side chains shows a crystalline state at room temperature, and the ordered structure disappears at high temperature. The phase transition from a crystalline state to a liquid-crystalline state was observed obviously only for copolymer Vb . In addition, the II-A isotherms and A-T isobars of these copolymers were measured and their stable LB films were also prepared. © 1996 John Wiley & Sons, Inc.     

Synthesis and properties of poly(acrylamide)s containing both long chain alkyl groups and phosphatidylcholine analogues in the side chains

A series of new phospholipid analogous acrylamide monomers ( 4a–e ) containing long alkyl chains as hydrophobic groups and containing phosphatidylcholine analogues as hydrophilic group were synthesized in high yields. The homopolymerizations and copolymerization ( 4b with 4e ) were carried out in the presence of a radical initiator. The structures and thermal properties of these polymers were investigated by x-ray diffraction analysis, DSC, and polarizing microscopy measurements. It has been revealed that these homopolymers ( 5b, 5c , and 5d ) which bear saturated long-hydrocarbon chains in the side chains exhibited not only orderly stacked bilayer structures at room temperature but also clear liquid crystalline behavior within a wide temperature range. The viscosity behavior of all polymers was found similar to usual polyelectrolytes in porlar solvent. The polymers obtained were also characterized by ¹H-NMR, IR, and melting point, respectively. © 1996 John Wiley & Sons, Inc.     

Lithium potassium borate and lithium rubidium borate: new non‐linear optical crystals

The title compounds, LiKB₄O₇ and LiRbB₄O₇, are newly developed non‐linear optical crystals containing two kinds of anionic groups, namely (B₃O₈)^7? and (B₅O₁₀)^5?. The (B₃O₈)^7? groups form infinite spiral chains parallel to the [100] direction, which are interconnected by sharing O atoms with (B₅O₁₀)^5? groups.     

Stilbenoids isolated from stem bark of Shorea hemsleyana

Two new stilbene glucosides [(+)-alpha-viniferin 13b-O-beta-glucopyranoside and resveratrol 12-C-beta-glucopyranoside] and two new resveratrol oligomers, hemsleyanols A and B, were isolated from the bark of Shorea hemsleyana along with four known resveratrol oligomers. The structures of the isolates, including the relative configurations, were established by spectroscopic data involving long-range coupling and nuclear Overhauser effect experiments.     

Novel,Complex Flavonoids from Mallotus philippensis (Kamala Tree)

One new flavanone, 4′‐hydroxyisorottlerin ( 2 ), and two new chalcone derivatives, kamalachalcones C ( 3 ) and D ( 4 ), were isolated from Mallotus philippensis (kamala tree). The largest compound ( 4 ; M_r 1098 g/mol) was shown to possess a unique, fused‐ring system made of two hydroxy‐chalcone units, giving rise to eight fused benzene/pyran units. From the same plant, the following six known compounds were also isolated: kamalachalcone A ( 5 ) and B ( 6 ), isoallorottlerin ( 7 ), isorottlerin ( 8 ), 5,7‐dihydroxy‐8‐methyl‐6‐prenylflavanone ( 9 ); 6,6‐dimethylpyrano(2″,3″: 7,6)‐5‐hydroxy‐8‐methylflavanone ( 10 ), and rottlerin ( 1 ). The structures of the new compounds were confirmed by in‐depth spectral analyses, including 2D‐NMR techniques, and the full ¹³C‐NMR assignments of the known flavanones 1 and 7 – 10 are published for the first time.