8β-hydroxyeremophil-7(11)-ene-12,8α(4β,6α)-diolide分子的晶体结构

运用层析法、结晶法从狭苞橐吾全草中分离得到艾里莫芬烷型倍半萜8β-hydroxyeremophil-7(11)-ene-12,8α(4β,6α)-diolide化合物,并通过质谱、核磁共振氢谱和碳谱、氢核-氢核相关谱、异核多量子相干谱和异核多键相干谱进行结构鉴定．其单晶经X射线衍射测试表明,其晶体属正交晶系,空间群为P212121,晶胞参数为: a=6．8519(5),b=10．7191(8),c=18．5942(14)A,V=1365．67(18) A3,Z=4,Dc=1．354 mg／m3．F(000)=592,μ=0．101 mm-1     

4,4,5,5-四甲基-1,3,2-二氧硼戊环的11B NMR及1H-11B HMQC研究

以4,4,5,5-四甲基-1,3,2-二氧硼戌环分子为研究对象,对碳硼烷类化合物的核磁共振(NMR)检测方法进行了研究.除了采用常规的核磁共振碳谱(~(13)C NMR)、氢谱(~1H NMR)及其二维相关谱外,引入核磁共振硼谱(~(11)B NMR)与二维异核多量子相关谱(~1H-~(11)B HMQC),对含硼类化合物结构进行了测定,该方法对于准确解析硼烷类化合物的结构具有较好的参考意义.     

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.     

1,2-二氢-4-(4-羟基苯基)(2H)二氮杂萘-1-酮的NMR研究

应用多种二维核磁共振谱,即：2D同核化学位移全相关谱(TOCSY),2D NOESY谱,2D 异核多量子相关谱(HMQC)和2D异核¹³C-¹H多键 相关谱(HMBC),对化合物1,2-二氢-4-(4-羟基苯基)(2H)二氮杂萘-1-酮的¹H和¹³C NMR 谱线进行了完整归属,从而系统地分析和讨论了该化合物的结构特征.     

三苯基锡4-吡啶甲酸酯的合成和晶体结构研究

利用三苯基氢氧化锡与4-吡啶甲酸在乙醇溶液中以摩尔比1:1反应,合成了有机锡化合物[Ph3SnO2CC5H4NH2O]n.通过元素分析、红外光谱、核磁共振氢谱和X-射线单晶衍射对其结构进行了表征.该化合物为正交晶系,空间群P212121,a=1.22176(19),b=1.4971(2),c=2.4313(4)nm,Z=8,V=4.4471(12)nm3,Dc=1.464g/cm3,μ=1.172mm-1,F(000)=1968,R=0.0437,wR=0.0674.该化合物中心锡原子为五配位三角双锥构型,并且通过4-吡啶甲酸配体的氮原子桥联作用形成一维无限链状结构.     

三维超分子化合物(C_(20)O_2H_(14))(C_(12)N_2H_8)的合成、晶体结构与荧光性质

合成了一个三维超分子化合物(C20O2H14)(C12N2H8)(命名为BP1),通过元素分析、红外光谱、核磁共振氢谱和X射线单晶衍射对其结构进行了表征,结果表明分子之间通过氢键和π-π堆积弱的相互作用形成超分子化合物。对所有合成的超分子化合物进行了紫外光谱和荧光光谱的测试。在室温DMSO溶液中,当激发波长为342 nm时,化合物在373 nm处有一强发射峰,呈现紫色荧光,这可以归属于分子内的π*→π跃迁。X射线单晶衍射分析结果表明,该超分子化合物属于三斜晶系,P1空间群,晶胞参数a=1.087 8(2)nm,b=1.125 2(2)nm,c=1.168 0(2)nm,α=97.89(3)°,β=110.91(3)°,γ=109.62(3)°,V=1.203 2(4)nm3,Z=2,R1=0.053 1,wR2=0.163 4,GOF值为1.034。     

1,3,5,7-四甲基-2,6,8-三乙基吡咯甲川-BF2络合物的合成及晶体结构

合成了标题化合物 ,借助于元素分析、红外光谱、核磁共振氢谱、质谱以及X 射线单晶衍射等分析方法确定了它的结构。该化合物属于三斜晶系 ,空间群为P-1(No 2 ) ,化学式 :C19H2 7BF2 N2 。晶胞参数 :a =1 2 2 5 7( 2 ) ,b=1 7830 ( 8) ,c=0 8877( 2 )nm ,α =10 0 2 6 ( 2 ) ,β =10 7 5 7( 1) ,γ =76 96 ( 2 )°,V =1 7892( 9)nm3 ,Mr=332 2 4,Z =4,Dc=1 2 33g·cm-3 ,μ(MoKα) =0 86cm-1,F( 0 0 0 ) =712 0 0 ,R =0 0 5 1,Rw=0 0 6 0。化合物中除 2 ,6 ,8位的三个甲基 (C( 12 ) ,C( 15 ) ,C( 18) )和氟原子 (F( 1) ,F( 2 ) )外 ,其余非氢原子近似组成一个大平面结构。在对其晶体结构进行详细分析的基础上 ,我们还初步讨论了它的分子结构与光谱及激光性能的关系。     

3S-7-羟基蜂蜜曲霉素分子的晶体结构

从红树林内生真菌Xylariasp．2508中分离到一个新的蜂蜜曲霉素型化合物3S-7-羟基蜂蜜曲霉素,这是首次从海洋真菌中获得该类结构的化合物并测定其晶体结构．通过核磁共振谱、红外光谱、质谱进行结构鉴定．其单晶经X射线衍射测试表明,该化合物晶体属单斜晶系,空间群为P21,化学式为C10H12O5,Mr=212．20．晶胞参数为:a=10．8884(19)(A|。),b=7.2284(13)(A|。),c=13．398(2)(A|。),β=104．217(3)°,V=1022．2(3)(A|。)3,Z=4,Dc=1．379 mg／m3, F(000)=448,μ=0．112 mm-1．结构由直接法解出,用全矩阵最小二乘法修正,最终偏离因子R=0．0498,wR=0．101．该分子由一个苯并吡喃环组成．通过与文献中已知3R-7-羟基蜂蜜曲霉素的熔点及旋光度对照,确定其绝对构型为3S．其初步抑菌实验结果表叫,3S-7-羟批蜂蜜曲霉素菌在每纸片200μg的剂量下对金黄色葡萄球菌(Staphylococcus aureus)没有表现出抑菌活性．     

绣线菊碱Ⅲ的结构研究

利用核磁共振谱对绣线菊碱Ⅲ(Spirasine Ⅲ)结构中的碳,氢信号作了归属,用同核相关谱和异核相关谱分析了噁唑烷环存在带来的双信号问题,指认出C_1,R,S两种构型的信号并对噁唑烷环的ABXY体系做了模拟。     

Formation of [3]Pseudorotaxanes from β-cyclodextrin and a Series of Dicarboxylic Acids with Their Corresponding α,ω-alkanedicarboxylate Anions

通过研磨法和共沉淀法成功制得β-环糊精与碳原子数11~15的脂肪族二元酸包合物,并通过傅立叶变换红外光谱(FTIR)、差热分析(DTA)以及X射线衍射(XRD)的方法确证了该包合物为[3]准轮烷结构．上述包合物通过与NaOH作用得到了β-环糊精与脂肪族二元酸双负离子的包合物并通过核磁共振氢谱(1H-NMR)及二维NOSEY谱确认了该包合物同样具有[3]准轮烷结构．     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.