基于联合变换相关器的像移测量仿真分析

对基于联合变换相关器的像移测量数学原理进行了说明,介绍了面阵CCD的安装位置以及输入图像的获取方法,分析了低信噪比输入图像、相对转动位移对测量精度的影响。应用MATLAB对输入图像进行傅里叶变换得到联合功率谱,对二值化处理的功率谱进行傅里叶变换得到相关输出,用质量中心算法计算出像移量。分析得出,输入图像信噪比大于5dB,测量均方误差小于0.05像素;输入图像相对转动位移在0.1°的范围内,转动位移对测量精度和峰噪比的影响可以忽略不计。综合分析表明像移测量均方误差小于0.05像素。     

NEAR-UV ACTIVATION OF ENZYMATIC CONVERSION OF 5-HYDROXYTRYPTOPHAN TO SEROTONIN

Near-UV (337 nm) photoactivation of the 5-hydroxytryptophan decarboxylation reaction producing serotonin has been observed. The photoactivation effect was investigated as a function of fluence rate and fluence, and pH. Photoactivation of decarboxylase activity was found to occur at nearly neutral pH values (low activity of the enzyme in the dark). The findings indicate that the effect of light is similar to a pH shift toward the acid region, which causes the enzyme conversion from the inactive to active form. Pyridoxal phosphate, the decarboxylase cofactor, in the form of an adduct absorbing at 330-340 nm, is suggested as a candidate for the role of the photoactive chromophore of decarboxylase.     

Molecular and crystal structures of the complex of 18-dehydroglycyrrhetic acid with dimethyl sulfoxide

The crystal structure of the complex of 18-dehydroglycyrrhetic acid (GLD) with DMSO (C₃₀H₄₁O₄·C₂H₆OS) has been determined by x-ray structural analysis. Syntex P21 diffractometer, CuK radiation, 1309 reflections, R = 0.080. A conformational analysis has been made of the GLD molecule in comparison with that of glycyrrhetic acid. The conformations of rings A and B in the GLD molecule do not differ from the conformations of the corresponding rings of glycyrrhetic acid. Differences arise in ringsC,D, andE because of the presence of the double bond between the C18 and C19 atoms.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 362–366, May-June, 1996. Original article submitted Novemher 11, 1995.     

Transition Metal Ion-binding Properties of a 14-Membered N2O2S2- Macrobicyclic Ligand

The selective liquid–liquid extraction of various transition metal cations from the aqueous phase to the organic phase was carried out using a 14-membered N₂O₂S₂-macrobicycle. Metal picrates such as Pb²⁺, Co²⁺, Zn²⁺, Ni²⁺,Cu²⁺ and Cd²⁺ were used in this extraction studies. It was found that the ligand showed moderate selectivity towards Pb²⁺ only among the other metals. The extraction constant (log K _ex) was determined to be 13.8 for Pb²⁺ complex.     

Temperature-dependent selectivity of inclusion by <Emphasis Type="Italic">trans</Emphasis>-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid

From acetophenone solution with a small amount of water, a widely used clathrate forming compound, trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (DED), crystallizes either in the form of a clathrate with acetophenone (25°C) or in the form of hydrate (5°C). The clathrate of DED with acetophenone is triclinic, space group P-1 with the unit cell parameters: a = 8.5002(2) Å, b = 12.5247(8) Å, c = 12.8251(8) Å; α = 62.876(2)°, β = 80.454(2)°, γ = 89.789(2)°; V = 1194.4(1) ų, Z = 2; the molar ratio DED:acetophenone is 2:3. The clathrate is of channel type; the system of mutually intersecting channels propagates in [100] and [01–1] directions in the structure. The guest molecules of acetophenone are included in the channels and do not form any H-bonds with the host molecules of DED. The hydrate of DED crystallizes in monoclinic system, in space group C2/c, with the unit cell parameters: a = 31.770(6) Å, b = 8.503(2) Å, c = 12.888(3) Å; β = 104.26(3)°; V = 3374(1) ų, Z = 8; the molar ratio DED:water is 1:3. One of two carboxylic groups of the molecule of DED is deprotonated and the proton is incorporated into the hydroxonium ion H₃O⁺. The crystal structure of the hydrate of DED is of layer type with well distinguished hydrophobic and hydrophilic parts.     

Gas-chromatographic analysis of alkylated derivatives of carane and of cycloheptane in capillary columns

The retention indices of synthesized alkyl derivatives of carane and of cycloheptane in capillary columns with tricresyl phosphate and squalane at 70°C have been determined. The influence of the structure of the hydrocarbons studied on the values of their retention parameters is considered. An estimate is given of the nature of the interrelationship between the physical properties of these hydrocarbons and their retention indices on a nonpolar stationary phase.Institute of Physical Organic Chemistry, Academy of Sciences of the Belorussian SSR, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 427–432, July–August, 1986.     

Features of ZnO Nanocrystal Size Distribution in a Polymer Matrix

Physics of the Solid State - X-ray diffraction patterns of a photocurable epoxy acryl-based polymer composite with addition of ZnO nanocrystals are analyzed. We recover the size distribution...     

X-ray structure analysis of triacetyllagochilin and lagochilin tetraformate

The molecular structures of two diterpene lagochilins, triacetyllagochilin and lagochilin tetraformate, are determinated by x-ray structure analysis.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 142–144, March–April, 2000.     

The I2(B) predissociation by solving an inverse atoms-in-molecule problem

The valence electronic states of the iodine molecule are analysed by means of a simple atoms-in-molecule model which accounts for the lowest ²P states of iodine atoms and approximates the spin-orbit interaction by its atomic part. For this model, an inverse problem is solved, i.e. non-relativistic potential energy curves and diabatic couplings are determined by a least-squares fit to known relativistic potential energy curves. The resulting adiabatic wave functions are used to calculate the electronic matrix elements responsible for natural, hyperfine and magnetic predissociation of the iodine molecule in the B0⁺ _u: state. The results are in reasonable agreement with experimental data, being stable enough with respect to the variation of input relativistic potentials. They also indicate the importance of diabatic couplings between the non-relativistic states of the same symmetry.