苷类化合物研究(Ⅰ)——天麻苷类似物的合成

本文合成了16种天麻苷类似物,测定了它们的¹³CNMR和¹HNMR。依据NMR数据,这些化合物的端基构型指定为β构型。     

High Speed Signal Wavelength Conversion Using Stimulated Raman Effect in Ultrasmall Silicon-on-Insulator Optical Waveguides

We propose the high speed signal wavelength conversion based on stimulated Raman effect on silicon waveguides. Simulation results of non-return-to-zero （NRZ） pseudorandom bit sequence （2^7-1 code） at 500-Gb/s rate of conversion in an ultrasmall silicon-on-insulator （SOI） optical waveguide are presented by co-propagating pump optical field. The most attractive issue is that the inverted converted signal can be obtained at the same wavelength as that of primary signal. In addition, the conversion performances, including extinction ratio （ER） and average peak power of conversion signal, depend strongly on the launching pump intensity.     

固相萃取分离-电感耦合等离子体质谱(ICP-MS)法测定海产品中的无机砷

分别将N-(β氨乙基)-γ-氨丙基三甲氧基硅烷(AEAPTMS)、3-巯丙基三甲氧基硅烷(MPTMS)与四乙氧基硅烷(TEOS)水解共聚,制备氨基\巯基键合的硅胶材料。将此材料作为固相萃取(SPE)小柱的填充材料,建立了固相萃取快速分离富集海产品样品中五价砷As(Ⅴ)和三价砷As(Ⅲ),电感耦合等离子体质谱(ICP-MS)法测定海产品中无机砷的方法。研究了固相萃取小柱对无机砷的吸附原理、性能和洗脱条件,在pH=3~4范围内固相萃取小柱材料有良好的选择吸附性,利用硝酸(2%)可将As(Ⅴ)洗脱,利用硝酸(2%)+KIO3(0.1mol/L)可将As(Ⅲ)洗脱。实际样品检测的加标回收率在72.3%~102%,实现了海产品样品中无机砷形态快速、方便、准确的检测。     

苷类化合物研究 IV: 熊果苷类似物的合成

本文报道以1-溴-2,3,4,6-四-O-乙酰基-a-D-吡喃糖与苯二酚在氢氧化钠的丙酮-水溶液中反应, 生成熊果苷类似物. 由^1HNMR测定了糖苷的端基异构体.     

Combined effects of cycling endurance and total ionizing dose on floating gate memory cells

The combined effects of cycling endurance and radiation on floating gate memory cell are investigated in detail, and the obtained results are listed below. (i) The programmed flash cells with a prior appropriate number of program and easing cycling stress exhibit much smaller threshold voltage shift than without those in response to radiation, which is ascribed mainly to the recombination of trapped electrons (introduced by cycling stress) and trapped holes (introduced by irradiation) in the oxide surrounding the floating gate. (ii) The radiation induced transconductance degradation in prior cycled flash cell is more severe than those without cycling stress in the programmed state or erased state. (iii) Radiation is more likely to set up the interface generation in programmed state than in erased state. This paper will be useful in understanding the issues involved in cycling endurance and radiation effects as well as in designing radiation hardened floating gate memory cells.     

苷类化合物研究 IV: 熊果苷类似物的合成

本文报道以1-溴-2,3,4,6-四-O-乙酰基-a-D-吡喃糖与苯二酚在氢氧化钠的丙酮-水溶液中反应, 生成熊果苷类似物. 由^1HNMR测定了糖苷的端基异构体.