2-甲基-6-(2-甲苯基)-2-庚烯的波谱学研究

采用色谱法从蒲儿根花部位中分离得到2-甲基-6-(2-甲苯基)-2-庚烯,该化合物第一次以单体的形式得到,通过测定氢-氢相关谱(1H-1H COSY)、DEPT谱、异核单量子相关谱(HSQC)及异核多键相关谱(HMBC)等二维谱确定了该化合物的结构,并对该化合物的1H NMR和13C NMR谱进行了归属.     

海洋真菌Penicillium sp.中的环二肽类化合物

从南海采集的海泥中分离得到的海洋真菌Penicillium sp.中分离得到3种环二肽类化合物。通过理化性质和波谱数据分析鉴定了3种化合物的结构。它们分别是3-异丁基-6-异丙基哌嗪-2,5-二酮(1)、3-另丁基-6-异丁基哌嗪-2,5-二酮(2)、3-另丁基-6-异丙基哌嗪-2,5-二酮(3)。     

艾纳香中黄酮化合物的研究

从中药艾纳香(Blumea balsamifera DC)中分离得到两种新的黄酮化合物,应用NMR、MS、IR、UV等波谱数据,确定其化学结构为3,5,3'-三羟基-7,4'-二甲氧基黄酮(Ⅰ)和3,5,3',4'-四羟基-7-甲氧基黄酮(Ⅱ).     

长枝沙菜Hypnea Charoides次级代谢物的分离与结构鉴定

对采自中国南海的红藻长枝沙菜 Hypnea Charoides的次级代谢物进行研究 ,从中分离得到 4个化合物 ,通过核磁共振、质谱等现代波谱分析技术确定其结构为 :豆甾 - 5 ,2 2 -二烯 - 3β-醇 - 3- o- β- D-吡喃葡萄糖甙 ( Ⅰ)、1 - o-十六碳酰基 -甘油酯 ( Ⅱ )、棕榈酸 ( Ⅲ )、正二十四烷 ( Ⅳ ) ,这些化学成分均首次从长枝沙菜中分离得到。     

山绿茶化学成分的研究

硅胶柱色谱、凝胶柱色谱分离,高效液相色谱纯化,得到单体化合物,用各种有机波谱鉴定化合物结构。分离得到6个化合物,鉴定为:α-香树脂素(Ⅰ),乌索酸(Ⅱ),3β,19α-二羟基乌索-12-烯-24,28-二酸(Ⅳ),2α,3β,23-三羟基乌索-12-烯-28-羧酸(),3β,19α,20β-三羟基乌索-12-烯-24,28-二羧酸(V),3β,19α-二羟基乌索-12-烯-23,28-二羧酸(Ⅲ)。化合物Ⅰ,Ⅲ,Ⅳ,Ⅴ,Ⅵ都是首次从该植物中分离得到。     

1,8-二羟基-3-甲基-苯并［d,e］蒽酮的2D NMR研究

从中药芦荟(Aloe vera)中分离得到一个蒽酮类新化合物. 通过UV、IR、HREI-M S、¹H NMR和¹³C NMR及2D NMR(¹H-¹H COSY、HMBC、HMQC和J -resolved)方法， 鉴定其结构为：1,8- 二羟基-3-甲基-苯并［d,e］蒽酮. 文章的侧重点在于讨论该化合物的¹H和¹³C NMR信号的全归属.     

2-（二硝基亚甲基）-4，5-咪唑烷二酮的反应研究

2-(二硝基亚甲基)-4，5-咪唑烷二酮(1)是1998年首次报道的一个新化合物，是Latypov等在探索合成低感高能炸药1，1-二氨基-2，2-二硝基乙烯(FOX-7)的过程中得到的一个重要中间体，它去掉羰基开环即得FOX-7，     

中药水团花(Adina pilulifera)中2个色酮苷的NMR化学位移全归属

从采自广东的茜草科植物水团花Adina pilulifera根中分离鉴定出2个色酮苷类化合物Undulatoside B（1）和5,7-二羟基-2-甲基色酮-7-O-β-D-芹糖(1→6)-β-D-葡萄糖(2). 应用2D NMR实验技术对化合物1，2的结构进行了详细研究，并对其¹H和¹³C NMR信号进行了全归属.     

海洋真菌Gliocladium sp.中的甾体和酚类化合物

从山东乳山采集的海洋真菌Gliocladium sp.中分离得到2个甾体化合物和4个酚类化合物,经1H-NMR、13C-NMR和MS等现代波谱手段鉴定它们的结构分别为:麦角甾-5,7,22E-三烯-3β-醇(1)、23-甲基麦角甾-5,7,22E-三烯-3β-醇(2)、3-羟甲基苯酚(3)、4-甲基-1,2-二苯酚(4)、4-(2-羟乙基)苯酚(5)、2-羟基-6-甲基苯甲酸(6)。     

2-三苯基锗基乙基苯基酮、4-三氯锗基-4-甲基-2-戊酮及其类似物Raman及IR光谱

我们合成有机锗化合物的重要中间体 4-三氯锗基 - 4-甲基 - 2 -戊酮 ( A)、3-三氯锗基 -3,5,5-三甲基环己酮 ( B)、2 -三氯锗基 - 2 -苯基乙基苯基酮 ( C)、2 -三苯基锗基乙基苯基酮 ( D) ,测量了他们的 Raman和 IR光谱并进行了讨论。在化合物 A- D的 Raman和 IR光谱 ,苯环中的 C- H伸缩振动 ,饱和 C- H伸缩振动 ,饱和 Ge- C伸缩振动等特征数据基本一致。C=O伸缩振动在 Raman和 IR光谱中位置基本一致 ,但在红外光谱中均为强吸收带 ,而在 Raman光谱中的峰强度差别则非常大 ,化合物 A、D的峰非常弱 ,而 C的峰则很强 ,化合物 A- C的 Ge- Cl振动均在 390 cm- 1附近出现强峰。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.     

Fiber Modal Index Measurements Based on Fiber Gratings

A novel method based on fiber gratings for measuring the effective indices of fiber modes is proposed. The effective index difference between the core mode and a cladding mode was obtained by analyzing the interference fringe of a pair of cascaded long-period fiber gratings. In order to extract the core mode index from the measured index difference, an index matching oil immersion method is proposed. By analyzing the interaction between the cladding mode and the oil applied on the cladding surface, the mode order and the effective index of the involved cladding mode might be calculated. Experimental results about the interference fringe shifts induced by the oil index and the oil-applied length are also presented.     

Optical Pulse Compression Schemes That Use Nonlinear Bragg Gratings

Nonlinear optical pulse compression of picosecond pulses typically requires long lengths of optical fiber and multiple components. Periodic structures, such as fiber Bragg gratings, are highly dispersive at wavelengths outside of the photonic bandgap. This implies that such gratings can be used as very short all-fiber compressors. In this paper a number of such compression schemes are reviewed involving uniform and nonuniform fiber Bragg gratings, relying on both soliton and nonsoliton compression principles. Experimental results supporting the corresponding underlying theory are also presented. Finally, an extension of one of the compression schemes is shown, which allows the generation of adjustable high-repetition rate soliton trains.