Synthesis and Characterization of a Novel Podophyllotoxin Derivative Containing a Cyclohexadienone Group

4β-Azido-4-demethyl-4'-O-demethyl-epipodophyllotoxin reacted with phenyliodonium diacetate in MeOH at room temperature to synthesize a novel podophyllotoxin derivative containing a cyclohexadienone group with the original configurations of C2 and C4,which are required for the antitumor activities.The component and structure of the pro-duct were confirmed using elemental analysis,high-resolution mass spectrum,1H and 13C NMR spectra,and infrared spectrum.Furthermore,the fragmentation routes of the product were fully assigned with electron-impact time-of-flight mass spectrometry(EI-TOF MS),which can also be used for the structural elucidation based on the molecular ion at m/z 455(16%)and three novel characteristic fragment ions at m/z 183(37%),425(7%),and 199(5%).The cyclohexadienone product is sensitive to acidic media.When it is treated with a trace of acid,another novel derivative containing an orthoquinone moiety is formed,which links with the metabolism of the cancer inhibitors.     

Investigating bottom-quark Yukawa interaction at Higgs factory

Measuring the fermion Yukawa coupling constants is important for understanding the origin of the fermion masses and their relationship with spontaneously electroweak symmetry breaking.In contrast,some new physics(NP)models change the Lorentz structure of the Yukawa interactions between standard model(SM)fermions and the SM-like Higgs boson,even in their decoupling limit.Thus,the precise measurement of the fermion Yukawa interactions is a powerful tool of NP searching in the decoupling limit.In this work,we show the possibility of investigating the Lorentz structure of the bottom-quark Yukawa interaction with the 125 GeV SM-like Higgs boson for future e^+e^- colliders.     

内陆水体叶绿素a含量定量检测的研究

以武汉东湖为实验基地,通过对其水体的多次检测,获得了从2006年6月到9月4个月的东湖水体透射光谱,并与蒸馏水透射光谱进行比较,对东湖水富营养化程度进行了定性分析.采用一种新的测量方法得到叶绿素a浓度与677 nm和703 nm处相对强度的差值和比值有很好的线性相关性,建立了东湖水体叶绿素a含量的准确定量检测模型,为实现对东湖水实时、快速、准确监测提供了基础,为高精度遥感水质分析提供了参考.     

自启动的非归零/归零码和光电时钟信号发生器及码型转换

采用双波长注入一包含伪随机码发生器与相位调制器的光电振荡器可以同时得到非归零(NRZ)码,归零(RZ)码以及光,电时钟信号输出。该方案使用了光域耦合的双环路结构,在不增加有源器件的条件下实现边模抑制。相位调制器用于反馈调制并同时实现占空比可调的非归零码到归零码的转换。双波长的注入排除了编码信号在振荡器中引入的非时钟频率成分。实验给出了10 Gb/s工作速率下的结果,得到了抖动为637 fs的光信号输出。转换得到的归零码信号占空比约为33%。输出电时钟信号的相位噪声在频偏10 kHz处为-109 dBc/Hz,边模抑制比为58 dB。     

Organic Nanocrystals Based on a Solid-emission-tunable AIEgen for Cell Imaging

The development of fluorescent nanocrystals based on organic small molecules is of great importance in bioimaging due to the merits of easy modification,high brightness and excellent photostability,however suffering from the emission-detrimental aggregation-caused quenching(ACQ)effect.Herein,we successfully designed and synthesized an AIE-active di(N,N-dimethylaniline)-dibenzofulvene(named as NFTPE),which exhibits the crystallization-induced emission enhancement(CIEE)effect.Interestingly,two types of yellow-and orange-emissive crystals for NFTPE were obtained,exhibiting aggregation microenvironment-dependent emission tuning in the solid state.Single-crystal analysis and density functional theory(DFT)calculations reveal that different aggregation microenvironments result in the distinct molecular conformation for various emission.Excitingly,the crystallization of NFTPE in an aqueous solution under the assistance of amphiphilic PEG polymer matrices could be monitored in situ by the fluorescence changes,facilitating the preparation of NFTPE nanocrystals(NFTPE-NCs)by adjusting the aggregation microenvironment.The obtained NFTPE-NCs exhibit the superior performance in cell imaging in respect to high brightness,photostability,and biocompatibility,thus demonstrating the potential in bioimaging applications.     

黑荆树皮中缩合单宁的提取

采用微波法、超声波法和高压蒸煮法从黑荆树皮中提取缩合单宁,探索了它们的最佳提取工艺条件,并对这些提取方法进行了比较.实验发现微波法是提取缩合单宁的最佳方法.用IR、UV、TG-DTA分析和XRD分析对微波法在最佳条件下提取的缩合单宁进行了表征.     

光纤中高斯型伪随机序列码偏振度的理论分析和实验研究

推导了准单色光波情况下高斯脉冲伪随机序列偏振度的简洁数学表达式.理论分析结果表明,偏振度与差分群延迟之间的关系与线路啁啾和光纤色散无关,并且此关系可以由光信号频谱半宽度Δω和分光比γ唯一确定.用10 Gbit/s 7级m序列归零码进行的实验表明:实验结果与理论推导基本一致,从而验证了推导公式的正确性.     

微波消解-石墨炉原子吸收光谱法测定菜籽及饼粕中铅和镉

目前菜籽及饼粕的综合利用越来越受到人们的重视,同时重金属的污染问题也日益引起人们广泛的关注,因此测定菜籽及饼粕中铅和镉的含量具有十分重要的意义。文章研究了微波消解溶剂、微波时间和压力对样品消解效果的影响,优化了石墨炉原子吸收光谱法测定条件,建立了一种快速检测菜籽及饼粕中铅、镉含量的有效方法。研究表明,铅、镉的检出限分别为2.172 μg·L-1(54.30 ng·g-1)、0.243 μg·L-1(6.075 ng·g-1),其线性范围分别为0～100 μg·L-1,0～8 μg·L-1;样品测定回收率在80.8%～110.7%之间,RSD小于5.3%。该法具有检出限低、灵敏度高、快速、准确的特点,用于实际样品测定的结果令人满意。     

基于法布里-珀罗干涉的全光纤振动检测仪

在传统的振动测量中,激光监测装置只能测量电机的单个参数.为实现对轴中心高为56 mm及以上电机的机械振动测量,建立了双通道独立测量系统.该系统可用于同时测量电机转轴的速度以及转轴产生的振动.该实验基于法布里-珀罗干涉、散斑干涉原理得到含有振动信号和速度信号的混合信号,将合成信号分解后,运用希尔伯特变换解调振动信号以及自...