超临界流体色谱法分析大豆磷脂

 采用以CO2 为流动相的超临界流体色谱方法 ,以含 0 0 5 % (体积分数 )三乙胺的乙醇作为改性剂 ,对具有重要生物功能的大豆磷脂组成进行分析 ,获得了大豆磷脂提取物中 6个重要组分的定性结果 ,并讨论了流动相组成、操作温度和压力对分离的影响。对其中有代表意义的磷脂酰胆碱 (PC)进行了外标法定量分析 ,在PC质量浓度为0 0 2 0 g/L～ 0 0 75 g/L时具有较好的线性关系 ,PC加样回收率为 96 7% (n =5 ) ,重现性好。此方法可用于实际样品的分析。     

杂化MCM-41固载催化剂的合成、表征及催化研究

用γ-氯丙基三乙氧基硅烷和正硅酸乙酯混合在模板剂引导下共水解合成了有机-无机杂化的介孔分子筛MCM-41,通过与(1R,2R)-1,2-环己二胺和[RuCl2(p-cymene)]2反应,制成了固载化的不对称氢转移反应催化剂,并进行了FT-IR、XRD和N2吸附 脱附的表征.不对称氢转移催化反应结果表明,在催化还原苯乙酮成α-苯乙醇的反应中,平均转化率为6.42％,产物平均ee（对映体过量）值为12.64％,固载化催化剂与其匀相体系的催化性能相比(转化率为3.56％,ee值为33.04％),转化率更高,ee值有一定程度的降低.     

Micronization of the officinal component emodin via the SEDS process through prefilming atomization

The micronization of emodin in a mixed solution of dichloromethane and methanol by the Solution Enhanced Dispersion by Supercritical Fluids through Prefilming Atomization (SEDS‐PA) process has been successfully performed. Morphologies and particle sizes (PSs) of the emodin microparticles were analyzed by scanning electron microscopy. The results of micronization show that the acicular or rod‐like emodin crystals with PSs of about 3‐10 µm wide and 100‐300 µm long have successfully been micronized to needle‐like, rod‐like, twisted fiber‐like and coalesced net‐like microparticles with PSs of about 0.1‐1.0μm wide and 2‐40μm long by the SEDS‐PA process. The effect of technological conditions on micronization has been studied. With the increase of initial solution concentration and temperature, the PSs of emodin microparticles increase. With the increase of solution flow rate and pressure, the PSs of emodin microparticles decrease. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Demonstration and operation of quantum harmonic oscillators in an AlGaAs-GaAs heterostructure

Frontiers of Physics - Nonreciprocal microwave devices, in which the transmission of waves is non-symmetric between two ports, are indispensable for the manipulation of information processing and...