考虑事故风险损失的爆炸物品经济订货批量模型研究

爆炸物品在储存过程中存在发生爆炸事故,从而给人类和环境带来伤害的可能,因此在对爆炸物品进行采购决策时必需考虑由此带来的风险损失.在给出爆炸物品事故风险损失度量方法的基础上,建立了爆炸物品的经济订货批量模型,证明了模型存在唯一最优解,并给出了模型的求解步骤,为相关企业合理制定采购决策提供了理论依据.数字算例分析了事故概率、赔偿标准、单位库存费、单次采购费对最优批量的影响,比较了考虑事故风险损失与否时的最优批量,结果表明,当事故概率或赔偿标准较高时,两者对应的最优批量差异明显.这也说明,当事故概率或赔偿标准达到一定程度时,考虑事故风险损失是十分必要的.     

Bounds on partial derivatives of NURBS surfaces

In this paper, we estimate the partial derivative bounds for Non-Uniform Rational B-spline(NURBS) surfaces. Firstly, based on the formula of translating the product into sum of B-spline functions, discrete B-spline theory and Dir function, some derivative bounds on NURBS curves are provided. Then, the derivative bounds on the magnitudes of NURBS surfaces are proposed by regarding a rational surface as the locus of a rational curve. Finally, some numerical examples are provided to elucidate how tight the bounds are.     

Investigation into Sonogashira reaction on 5-iodo-1-(phenyl/p-halophenyl)imidazole-4-carbonitrile compounds

Investigation into Sonogashira reaction on 5-iodo-1-(phenyl/p-halophenyl)imidazole-4-carbonitrile compounds had been developed by introducing an iodo atom at the C-5 position of the imidazole ring of 5-amino-1-(phenyl/p-halophenyl)imidazole-4-carbonitrile compounds. Specifically, 5-iodo-1-(4-iodophenyl)imidazole-4-carbonitrile compound had shown double Sonogashira coupling reactions with two differently substituted iodine along with the formation of two other compounds where an unusual coupling product with self-aggregation property was obtained. In other cases, monocoupling had been observed together with another compound where iodine atom present at C5 position of imidazole was replaced by hydrogen atom.     

New biphenantherene and nervogenic acid derivatives from Liparis regnieri Finet and their inhibitory activities against NF-κB activation

A phytochemical investigation of the whole plant of Liparis regnieri Finet led to the isolation of one new biphenantherene (1) and ten new nervogenic acid derivatives (2–11), together with nine known compounds. Their structures were elucidated mainly by extensive analyses of 1D and 2D NMR spectroscopic data and chemical reactions. Additionally, for the first time a previously unreported biphenantherene was discovered to effectively suppress TNF-α induced expression of NF-κB-Luc in Hela cells with the IC₅₀ value of 1.80 μM and the structure-activity relationshipwas also discussed.     

Simultaneous Spectrophotometric Determination of Imipramine Hydrochloride with Chlordiazepoxide and Nortriptyline Hydrochloride with Fluphenazine Hydrochloride

Spectrophotometry was used with multivariate calibration to simultaneously determine compounds in mixtures. Two antidepressant mixtures were investigated: imipramine hydrochloride and chlordiazepoxide and nortriptyline hydrochloride and fluphenazine hydrochloride. Considerable spectral overlap and large differences in component concentrations were challenges. Since this type of analysis is often performed using complex algorithms, a simple strategy was used here for the simultaneous determination of both mixture components by classical least squares, principal component regression, and partial least squares. Experimental design was used to select the optimum parameters including the wavelength range, sampling interval, software, and derivative order. Accuracy was enhanced by proper wavelength selection. In addition, derivatives of the raw spectra improved the selectivity. The standard deviation, deviation of mean recovery from 100%, and prediction ability of the models were used as the responses. In respect to these terms, first-order derivatization of the spectra and a sampling interval of 1?nm provided the best results. In particular, the low concentration compounds in the mixtures (chlordiazepoxide and fluphenazine) were determined more accurately with precision lower than 3%. The strategy was used for the quality control of pharmaceuticals containing the mixtures without chemical pretreatment.     

Silver(I) complex with 2-amino-4,4α-dihydro-4α,7-dimethyl-3H-phenoxazin-3-one (Phx-1) ligand: crystal structure,vibrational spectra and biological studies

The first metal complex of Phx-1 ligand, bis(2-amino-4,4α-dihydro-4α,7-dimethyl-3H-phenoxazin-3-one)nitratosilver(I), [Ag(Phx-1)₂NO₃], has been obtained and investigated by single crystal X-ray diffraction and vibrational spectroscopy methods. The Ag⁺ is bonded to heterocyclic nitrogen atoms of two organic ligands and one oxygen atom of a nitrate anion. The Phx-1 ligand coordination mode is supported by IR and Raman spectra, interpreted with the help of theoretical DFT studies. The antibacterial activity of the ligand and its Ag(I) complex as well as some reference compounds were screened against Gram-positive and Gram-negative bacteria, applying microdilution procedures. High sensitivity to the studied complex was found for Rhodococcus erythropolis and Bacillus licheniformis strains. Modified Phx-1 ligand preparation procedures are also presented.     

Highly enantioselective Michael addition of α,α-disubstituted aldehydes to maleimides catalyzed by new primary amine-squaramide bifunctional organocatalysts

New bifunctional primary amine-squaramides catalyzed asymmetric Michael addition reaction of α,α-disubstituted aldehydes to maleimides has been developed. This organocatalytic asymmetric reaction provides easy access to functionalized succinimides with a broad substrate scope. Both enantiomers of desired succinimide derivatives were obtained in good to excellent yields (up to 98%) with excellent enantioselectivities (up to >99%?ee).     

A pyrene-based dual chemosensor for colorimetric detection of Cu2+ and fluorescent detection of Fe3+

A pyrene based chemosensor was designed and synthesized. The pyrene fluorophore was connected with a pyridine unit through a Schiff base structure to give the sensor (L). L was tested with a variety of metal ions and exhibited high colorimetric selectivities for Cu²⁺ and Fe³⁺ over other ions. Upon binding with Cu²⁺ or Fe³⁺, L showed an obvious optical color change from colorless to pink for Cu²⁺ or orange for Fe³⁺ over a wide pH range from 3 to 12. Moreover, the fluorescence of L at 370 nm decreased sharply after bonding with Fe³⁺, while other metal ions including Cu²⁺ had no apparent interference. Thus, using such single chemosensor, Cu²⁺ and Fe³⁺ can be detected independently with high selectivity and sensitivity. The limits of detection toward Cu²⁺ and Fe³⁺ were 8.5 and 2.0 μM, respectively. DFT calculation results also proved the formation of stable coordination complexes and the phenomenon of fluorescence quenching by Fe³⁺. Furthermore, L was also successfully used as a bioimaging reagent for detection of Fe³⁺ in living cells.     

Three‐body expansion of the fragment molecular orbital method combined with density‐functional tight‐binding

The three‐body fragment molecular orbital (FMO3) method is formulated for density‐functional tight‐binding (DFTB). The energy, analytic gradient, and Hessian are derived in the gas phase, and the energy and analytic gradient are also derived for polarizable continuum model. The accuracy of FMO3‐DFTB is evaluated for five proteins, sodium cation in explicit solvent, and three isomers of polyalanine. It is shown that FMO3‐DFTB is considerably more accurate than FMO2‐DFTB. Molecular dynamics simulations for sodium cation in water are performed for 100 ps, yielding radial distribution functions and coordination numbers. © 2017 Wiley Periodicals, Inc.     

交换L*-环

我们证明一个交换整环或交换局部环是一个L*-环当且仅当它是一个O*-环.文中还证明了一些一般性的条件使之一个交换环不是L*.