Molecular imprinting of bisphenol A and alkylphenols using amylose as a host matrix

A novel molecularly imprinted polymer has been created by a radical polymerisation of acryloylamylose in the presence of a template.     

Short syntheses of (+/-)-delta-araneosene and humulene utilizing a combination of four-component assembly and palladium-mediated cyclization

[reaction: see text] The four components shown are assembled in two steps, and the product is converted to araneosene by a short sequence.     

Enantioselective synthesis of the protein phosphatase inhibitor (-)-motuporin

A highly convergent asymmetric synthesis of the protein phosphatase inhibitor motuporin 1a is described. Synthesis and coupling of the individual peptide fragments [34 + 35 --> 51] followed by macrocyclization afforded the fully protected motuporin precursor 33, which is converted to the natural product by dehydration and ester hydrolysis. Six of the eight stereogenic centers associated with the natural product were introduced using asymmetric crotylsilane bond construction methodology. Our approach features an efficient Pd(0)-catalyzed cross-coupling reaction between a configurationally well-defined vinyl zinc intermediate 22 and an (E)-vinyl iodide 7, which afforded compound 43, resulting in the construction of the trisubstituted (E,E)-diene system of the motuporin side chain. Improved reaction conditions for macrocyclization in the formation of 33 are also detailed.     

Porous solgel fiber as a transducer for highly sensitive chemical sensing

A novel solgel process for making porous silica fiber and doping the fiber core with sensing material is described. A CoCl(2) -doped solgel fiber was fabricated and was used to construct an active-core optical fiber moisture sensor. Test results show that the sensitivity of the active-core optical fiber sensor is much higher than that of an evanescent-wave-based optical fiber sensor.     

Calculation of electron wave functions and refractive index of Ne

The radial wave functions of inner electron shell and outer electron shell of a Ne atom were obtained by the approximate analytical method and tested by calculating the ground state energy of the Ne atom. The equivalent volume of electron cloud and the refractive index of Ne were calculated. The calculated refractive index agrees well with the experimental result. Relationship between the refractive index and the wave function of Ne was discovered. Supported by the New Star Program of Beijing Science and Technology, China (Grant No. 952870400), the Beijing Municipal Commission of Education, and the Excellent Young Teachers Program of Ministry of Education, China     

基于面向对象技术的多媒体CAI素材库系统

建立实用、高效的多媒体ＣＡＩ素材库是高效率、高质量开发ＣＡＩ软件的基础和关键．本文从数据模型、面向对象分析和存储模式三方面入手,提出一种支撑ＣＡＩ制作工具的素材库体系结构,并讨论该体系结构的特性和进一步研究的问题．     

Effect of oxygen on superconductivity and structure of Bi-system superconductor

A systematic study of the effects of oxygen content and distribution in 2223 single-phase Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O_10+δ s superconductor has has been carried out using a combination of quenching in air and low-temperature annealing in nitrogen. With decreasing oxygen content a maximum was observed in T_c, accompanying the increase in room-temperature resistivity. Also the effect of oxygen redistribution has been studied by low-temperature annealing in nitrogen, which allows no oxygen content change. After this annealing, in T_c, the room temperature resistivity and the c-axis parameter an apparent change occurred as compared to the original quenching states. From tge measurement of in situ resistivity which increased gradually during low-temperature annealing, it seems that a metastable phase was formed by oxygen diffusion. The interchange of oxygen atoms between Bi₂O₂ and CuO₂ planes and the possible ordering of oxygen vacancies were proposed to explain the relevant experimental phenomena.     

激光二极管相对于铯饱和吸收D2线的无调制扰动三次谐波锁频

将频率调制加在声光调制器上 ,用三次谐波探测法获得了铯原子D2 线的三阶微分饱和光谱。采用这种激光器无调制扰动方案结合三次谐波锁频技术 ,实现了 85 2nm的分布布拉格反射器半导体激光器相对于 6S1/2 F =4- 6P3 /2 F′ =5超精细跃线的频率锁定。由锁定后的频率误差信号估算 ,10s内激光频率起伏小于± 35 0kHz ,相对频率稳定度约 1× 10 -9。这种无调制扰动方案可以消除一般的饱和吸收稳频方法中由于直接对激光器进行频率调制而带来的额外频率噪声 ;三次谐波锁频技术的应用 ,还可有效地降低铯原子饱和吸收谱中剩余多普勒背景的影响