Spectral and Mechanistic Studies of the Reactions of Substituted 1,5-Benzothiazepine with Dichloroacetyl Chloride and Triethylamine

A lot of attentions have been paid to the synthesis of benzothiazepines and derivatives1,2 due to their significant physiological activities. It has been reported that b-lactam, a major part of the antibiotic skeleton, can be introduced to a molecule by reaction of an imine moiety with ketene3,4. We introduced a b-lactam skeleton to benzothiazepine and hoped the new compounds may possess certain biological activities. SHNH3ClCHCHCOC2H5OHSNClCla: ortho-Clb: para-Cl+PyridineScheme …     

Synthesis and Study of Two-Photon Induced Fluorescence of Novel Dyes

Morerecently,thesynthesisofnewdyeswithlargeupconvertedfluorescencebecomesthefocusoftheresearchandhasopenedupamyriadofapplications.Theapplicationsincludetwo-photoninducedlasing',two-photonopticalpowerlimiting',threedimensionalopticaldatastorage',andphotodynamictherapy'.Nevertheless,thistechniquehasneverreacheditsfullpotentialduetothelackofdyeswhichexhibithighupconvertedfluorescentilltensity.ThisrepoFtdescribesthesynthesisandpropertiesoftwo-photoninducedfluorescencedyeswhicharespecificallydesign…     

气相色谱/质谱/质谱法分析石油基引燃物

应用Ｖａｒｉａｎ ３８００ ＧＣ／Ｓａｔｕｒｎ ２０００ ＭＳ 气相色谱／质谱联用分析仪（简称ＧＣ／ＭＳ／ＭＳ）对以汽油、煤渍和紫油为引燃物，燃烧聚丙稀化纤地毯和土壤时的模拟现场物品进行了引燃物的检出。发现采用ＧＣ／ＭＳ／ＭＳ方法比用ＧＣ／ＭＳ方法可以较彻底地排队由于柱注失、地毯燃物分解产物、土壤背景产物和地毯增塑剂等引起的干扰，而且可以提高检测灵敏度。详细考察了以不同质荷比的离子作母离子时对ＧＣ     

One-dimensional Coordination Polymers of rctt-1,3-Diphenyl-2,4-bis [2-（5-phenyl）- oxazolyl]cyclobutane with CuCI2 and COCl2

The Cu（Ⅱ） and Co（Ⅱ） supramolecular coordination polymers, [CuCl2（DPO）- （CH3CN）0.5（CH2Cl2）0.5]n （CuDPO, DPO = rctt-1,3-diphenyl-2,4-bis[2-（5-phenyl）oxazolyl]cyclo- butane） and [CoCl2（DPO）]n （CoDPO）, were synthesized and characterized by single-crystal X-ray diffraction method. CuDPO crystallizes in monoclinic, space group P21/n, with a = 11.243（5）, b = 16.070（8）, c = 19.872（9） A, β = 95.678（10）°, Z = 4, V= 3573（3） A3, C35.50H28.50Cl3CuN2.50O2, Mr = 692.00, Dc = 1.287 g/cm3, p = 0.868 mm^-1, F（000） = 1420, S = 1.089, （△/σ）max = 0.069, the final R = 0.0682 and wR = 0.1749. CoDPO is of monoclinie, space group P21/n, with a = 11.396（4）, b = 15.151（5）, c = 17.673（6） A, β = 90.528（6）°, Z = 4, V = 3051.4（17） A3, C34H26Cl2CoN2O2, Mr = 624.40, Dc = 1.359 g/cm3, μ = 0.770 mm^-1, F（000） = 1284, S = 0.981, （△/σ）max = 0.001, the final R = 0.0471 and wR = 0.0961. In each case, the metal cation is coordinated by two C1 anions and two N atoms from oxazole ring of the ligands, which leads to the formation of a one-dimensional polymeric structure. It is found that the cyclobutane ring of coordinated DPO adopts a distorted conformation in the crystal, which is attributed to the increased steric effect between adjacent aryl substituents for the coordination of oxazole ring to metal cation. Thermal gravimetric analysis of the two complexes was also observed.     

MgO缺陷和不规则表面吸附Cl2的电子结构研究

采用从头算程序对MgO表面 3种不同配位位置吸附Cl2 的构型进行优化 ,并用扩展休克尔紧束缚 (EHT)晶体轨道方法对MgO的缺陷和不规则表面吸附Cl2的可能构型进行能带计算 ,讨论了吸附前后能带组成和成键性质的变化。研究表明 :MgO表面吸附Cl2 将更趋向于吸附在O原子上而非Mg原子上 ,而且在 3种配位中MgO表面三配位氧最有利于吸附Cl2 ;吸附时 ,电子从O原子转移到Cl2 分子的反键轨道 ,但是各种吸附构型的MgO表面对Cl2 的吸附作用均比较微弱 ,是典型的物理吸附。     

Electromagnetically induced phase grating controlled by spontaneous emission

Electromagnetically induced phase grating controlled by spontaneous emission is studied. The results show that the diffraction efficiency of phase grating is strikingly enhanced due to the existence of spontaneously generated coherence (SGC), and the diffraction efficiency of 35% can be obtained in optimal SGC parameter case. Furthermore, at large SGC parameter, the high efficiency of phase grating can be maintained by the application of weak coupled and relatively strong probe fields, and choosing the proper length of atomic sample. At the same time, in such an atomic system, the SGC effect depends on incoherent pump.     

环精固定相—电化学检测测定肾上腺素和拟肾上腺素对映体

以乙酰化－β-环糊精作固定相，较系统地研究了流动相组成及柱温、流速等对肾上腺素类对映体分离的影响，优化了反相色谱流动相组成为0．06ml/LNaOA(pH5.0) 0.03mmol/L EDTA.2Na 2(vol)%CH3CN,工作电位E为＋0．60V。探讨了环糊精立体选择性与主－客体分子结构之间的关系。工作曲线的线性范围0－250μg/L，检测限低于0．60ng/L，相对标准偏差小于3．5％。     

Influence of structural defects on the optical properties of strongly coupled Au nanoshell arrays

The effects of different defects on optical properties and plasmon resonances properties of Au nanoshell arrays were investigated by using the finite-difference time-domain(FDTD) theory.It is found that the optical properties of the nanoshell arrays are strongly influenced by different defects.We show that when the hollow Au nanoshell arrays are placed in air,there is a wide photonic band gap(PBG) in the infrared region,but the band gap becomes narrower as we introduced different defects.Based on the distributions of electric field component E z and the total energy distribution of the electric and the magnetic field,we show that there exhibit dipoles field distributions for the plasmon mode at the long-wavelength edge of the band gap,but composite higher order modes are excited at the short-wavelength edge of the band gap.The plasmon resonant modes also can be controlled by introducing defects.     

Fresnel coefficients for a layer of NIM

Reflection and transmission of traveling and evanescent waves by a layer of material with a negative index of refraction (NIM) is studied by means of the Fresnel coefficients. We derive their values in the “NIM limit”, and we show that this limit is consistent with the exact solution. It is also indicated that simply substituting the negative values of the relative permittivity and permeability of the NIM material into the exact solution leads to incorrect results for evanescent waves.     

On the predictive ability of narrative disclosures in annual reports

We investigate whether narrative disclosures in 10-K and 10K-405 filings contain value-relevant information for predicting market performance. We apply text classification techniques from computer science to machine code text disclosures in a sample of 4280 filings by 1236 firms over five years. Our methodology develops a model using documents and actual performance for a training sample. This model, when applied to documents from a test set, leads to performance prediction. We find that a portfolio based on model predictions earns significantly positive size-adjusted returns, indicating that narrative disclosures contain value-relevant information. Supplementary analyses show that the text classification model captures information not contained in document-level features of clarity, tone and risk sentiment considered in prior research. However, we find that the narrative score is not providing information incremental to traditional predictors such as size, market-to-book and momentum, but rather affects investors’ use of price momentum as a factor that predicts excess returns.