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)。     

海洋放线菌fang-1的化学成分

采用硅胶柱色谱、凝胶柱色谱、高效液相色谱等方法对放线菌fang-1化学成分进行分离和纯化,根据质谱、核磁共振图谱鉴定单体化合物结构.分离得到5个化合物,分别鉴定为:环(苯丙氨酸-异亮氨酸)二肽(1),环(脯氨酸-异亮氨酸)二肽(2),环(酪氨酸-亮氨酸)二肽(3),环(亮氨酸-异亮氨酸)二肽(4),邻苯二甲酸二异丁酯(5).5个化合物均为首次从该菌中分离得到,其中化合物1-4为环二肽.     

Parisaponin Ⅰ和Parisvietnaside A的NMR数据分析

从滇重楼中分离得到2个甾体皂苷,利用1H NMR、13C NMR、1H-1H COSY、HSQC、HMBC、1D和2D TOCSY等多种核磁共振方法鉴定其结构分别为(25R)-26-O-β-D-吡喃葡萄糖基-3β,22α,26-三羟基-呋甾-5-烯-3-O-α-L-吡喃鼠李糖基-(1→2)-[α-L-呋喃阿拉伯糖基-(1→4)]-β-D-吡喃葡萄糖苷(1,Parisaponin I)和(25R)-3β,5α,6β-三羟基-△7-螺甾烯-3-O-β-D-吡喃葡萄糖基-(1→3)-[α-L-吡喃鼠李糖基-(1→2)]-β-D-吡喃葡萄糖苷(2,paris-vietnaside A).对化合物1和2的1H NMR和13C NMR信号分别进行了归属和详细分析,并纠正了文献中的核磁数据归属错误.化合物2为首次从滇重楼中分离得到.     

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)。     

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。     

网胰藻中的含氮化合物

从中国南海网胰藻(Hydroclathrus Clathratus)中分离得到4个含氮化合物,经波谱技术鉴定为:N-(2'-羟基-1'-羟甲基十五烷基)二十脂肪酸酰胺(Ⅰ)、尿嘧啶(Ⅱ)、1-(2-脱氧-β-D-呋喃核糖-5-甲基-1,2,3,4-四氢-2,4-二酮(Ⅲ)和2-苯胺基-1,4-萘二酮(Ⅳ),其中化合物Ⅳ为首次从自然界中分离得到.     

SiO2纳米粒子在毛细管电泳分离蛋白质中的应用

将SiO2纳米粒子作为添加剂用于溶菌酶、牛血清白蛋白、牛血红蛋白的毛细管电泳(CE)分离研究.对影响3种蛋白质分离的因素如缓冲溶液的浓度,SiO2纳米粒子、聚合物PVP、乙腈的含量,及分离电压、温度等进行了考察,得到最佳分离条件,即50mmol/L NaH2PO4-10mmol/L H3PO4缓冲溶液(pH=2.8),...     

软骨凹顶藻Laurencia Cartilaginea 甾醇成分的研究

从中国南海软骨凹顶藻乙醇浸提物的乙酸乙酯相中 ,首次分离得到一种环二氧麦角甾醇 :5α,8α-环二氧麦角甾 - 6 ,2 2 -二烯 - 3β-醇 (1)。通过 GC- MS方法检测到了其他 5种甾醇化合物 :5 ,8-环二氧麦角甾 - 1,6 ,2 2 -三烯 - 3-醇 (2 ) ,麦角甾 - 6 ,2 2 -二烯 - 5 ,8-二羟基 - 3-酮 (3) ,豆甾 - 6 ,2 2 -二烯 - 5 ,8-二羟基 - 3-酮 (4) ,麦角甾 -5 ,7,9(11) ,2 2 -四烯 - 3-醇 (5 )以及豆甾 - 5 ,7,2 2 -三烯 - 3-醇 (6 )     

1-(4-氯苯甲酰基)-4-[1′-N′-(2′,3′,4′,6′-四-o-乙酰基)-D-吡喃葡萄糖基]氨基硫脲与DNA相互作用的光谱及电化学研究

紫外 -可见光谱法和循环伏安法研究了 1- (4 -氯苯甲酰基 ) - 4- [1′- N′- (2′,3′,4′,6′-四 - o-乙酰基 ) - D-吡喃葡萄糖基 ]氨基硫脲与 DNA的相互作用。该试剂与 DNA作用后 ,引起 DNA的紫外特征吸收峰呈明显的减色效应和红移现象 ,通过该试剂对溴化乙锭 - DNA紫外 -可见光谱和循环伏安曲线的影响 ,证明它与DNA发生了嵌插作用。     

Parisaponin I 和Parisvietnaside A 的NMR数据分析

从滇重楼中分离得到2个甾体皂苷,利用¹H NMR、¹³C NMR、¹H-¹H COSY、HSQC、 HMBC、1D和2D TOCSY等多种核磁共振方法鉴定其结构分别为(25R)-26-O-β-D-吡喃葡萄糖基-3β, 22α, 26-三羟基-呋甾-5-烯- 3-O-α-L -吡喃鼠李糖基-(1→2)[α-L-呋喃阿拉伯糖基(1→4)]-β-D-吡喃葡萄糖苷（1, Parisaponin I）和(25R)-3β, 5α, 6β-三羟基-△7-螺甾烯-3-O-β-D-吡喃葡萄糖基-(1→3)[α-L-吡喃鼠李糖基-(1→2)]-β-D-吡喃葡萄糖苷（2, parisvietnaside A）. 对化合物1和2的¹H NMR和¹³C NMR信号分别进行了归属和详细分析,并纠正了文献中的核磁数据归属错误. 化合物2为首次从滇重楼中分离得到.      

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.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

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.