Molar extinction coefficients of some carbohydrates in aqueous solutions

Molar extinction coefficients of some carbohydrates viz. l-arabinose (C₅H₁₀O₅), d-glucose (C₆H₁₂O₆), d-mannose (C₆H₁₂O₆), d-galactose (C₆H₁₂O₆), d(-) fructose (C₆H₁₂O₆) and maltose (C₁₂H₂₄O₁₂) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying within experimental uncertainty. Within concentration ranges studied, Beer-Lambert law is obeyed very well.     

Photon mass attenuation coefficients,effective atomic numbers and electron densities of some thermoluminescent dosimetric compounds

Photon mass attenuation coefficients of some thermoluminescent dosimetric (TLD) compounds, such as LiF, CaCO₃, CaSO₄, CaSO₄.2H₂O, SrSO₄, CdSO₄, BaSO₄, C₄H₆BaO₄ and 3CdSO₄.8H₂O were determined at 279.2, 320.07, 514.0, 661.6, 1115.5, 1173.2 and 1332.5 keV in a well-collimated narrow beam good geometry set-up using a high resolution, hyper pure germanium detector. The attenuation coefficient data were then used to compute the effective atomic number and the electron density of TLD compounds. The interpolation of total attenuation cross-sections of photons of energyE in elements of atomic numberZ was performed using the logarithmic regression analysis of the data measured by the authors and reported earlier. The best-fit coefficients so obtained in the photon energy range of 279.2 to 320.07 keV, 514.0 to 661.6 keV and 1115.5 to 1332.5 keV by a piece-wise interpolation method were then used to find the effective atomic number and electron density of the compounds. These values are found to be in agreement with other available published values.     

Gamma or X-rays attenuation properties of some biochemical compounds

The probability of gamma or X-ray interactions with important 14 antioxidants have been discussed for total photon interactions in the wide energy range of 1?keV–100?GeV using the WinXCOM code. The variations of mass attenuation coefficient (μ_ρ), effective atomic number (Z_eff) and electron density (N_el) with photon energy were plotted for total photon interactions. It was found that the values of μ_ρ, Z_eff and N_el depend on the incoming photon energy and chemical compositions of antioxidant. The highest values of these parameters were found at a low-energy zone where the photoelectric effect is the dominant interaction process. When antioxidants were compared with each other, it was seen that Z_eff has the highest values for Oenin chloride and Delphinidin chloride which contain the Cl element. This investigation is thought to be useful for medical applications where radiation exposure is present.     

Molar extinction coefficients of IR absorption bands of Cu(II) dipivaloylmethanate

IR absorption spectra of an intracomplex chelate compound of Cu(II) bis-dipivaloylmethanate in the spectral range 4000–300 cm⁻¹ are investigated. A comparison is made between the spectra of the complex in different aggregative states: as a solution in heptane and as condensed films. The molar extinction coefficients of absorption bands are calculated. The extinction coefficients found are used to evaluate the thickness of Cu(dpm)₂ films. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 1, pp. 34–37, January–February, 2000.     

A study of photon interaction in some hormones

The effective atomic numbers (Z _eff) and electron density (N _el) of some hormones such as testosterone, methandienone, estradiol and rogesterone for total and partial photon interactions have been computed in the wide energy region 1 keV–100 GeV using an accurate database of photon-interaction cross sections and the WinXCom program. The computed Z _eff and N _el are compared with the values generated by XMuDat program. The computer tomography (CT) numbers and kerma values relative to air are also calculated and the computed data of CT numbers in the low-energy region help in visualizing the image of the biological samples and to obtain precise accuracy in treating the inhomogenity of them in medical radiology. In view of dosimetric interest, the photon absorbed dose rates of some commonly used gamma sources (Na-21, Cs-137, Mn-52, Co-60 and Na-22) are also estimated.     

Molar coefficients of extinction for IR absorption bands of Ni(II) acetylacetonate, ketoiminate, and trifluoroacetylacetonate

We have studied IR absorption spectra (within the spectral range of 4000-200 cm⁻¹ of the intracomplex chelate compounds Ni(II) bis-acetylacetonate, Ni(II) bis-ketoiminate, and Ni(II) bis-trifluoroacetylacetonate and have given a full interpretation and comparison of the spectra of these compounds in dissolved and solid states. The reasons for the differences in the spectra are discussed. The molar coefficients of extinction for the absorption bands are calculated. Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3, Akad. Lavrent’ev Ave., Novosibirsk, 630090, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 775–780, September–October, 1998.     

Uncertainty propagation of chemical kinetics parameters and binary diffusion coefficients in predicting extinction limits of hydrogen/oxygen/nitrogen non-premixed flames

A comprehensive investigation of the uncertainties associated with the experimental and numerical evaluation of the extinction strain rate in hydrogen/oxygen/nitrogen non-premixed flames is presented in this work. The reported new experimental uncertainties of the extinction strain rate include several sources of uncertainties that typically affect the characterisation of velocity and boundary conditions of counterflow flames via particle image velocimetry. The uncertainties associated with the numerical determination of the extinction strain rate not only depend upon the selected chemical kinetics parameters but also on the binary diffusion coefficients. In order to identify the major sources of uncertainties in the chemical and diffusion models, a Monte Carlo based high-dimensional model representation analysis of the extinction curve was performed. Independent and simultaneous perturbations of relevant chemical kinetics and diffusion parameters have shown that the uncertainties associated with the binary diffusion coefficients are about a factor of 10 smaller than the uncertainty due to chemical kinetics parameters. Since the experimentally well known binary diffusion coefficient for hydrogen and nitrogen, , accounts for most of the propagated uncertainty of the diffusion model, it is shown here that only a reduction of the uncertainty of chemical kinetics parameters will have a significant impact in improving the accuracy of the extinction strain rate predictions.     

Effective atomic numbers of some vanadium and nickel compounds for total photon interactions using transmission experiments

Effective atomic numbers of V₂O₃,VO₂,VF₃,NH₄VO₃,VF₄,NiF₂,NiCl₂,NiF₂4H₂O,NiCl₂6H₂O,Ni(ClO₄)₂6H₂O were measured in the X-ray energy range 15.746- using an Si(Li) detector. The measured values are compared with the theoretical ones calculated using WinXcom.     

Regaining profiles of extinction coefficients of optically dense scattering media in laser location measurements

We suggest a procedure for regaining spectral values of the extinction coefficients ε(r) of optically dense scattering media in laser location measurements. Allowance is made for the contribution of multiple scattering to a recorded signal and its correction for the degree of change of the qualitative composition of the scattering medium. The procedure can increase the accuracy of regaining ε(r) and eliminate the “edge effect” at the end of the probed path. The latter is achieved by determining a calibration constant from the transparency value of the whole probing range, which is calculated from back-scattered signals corrected based on the constancy of the lidar ratio. We present an algorithm for calculating the correction coefficient. The efficiency of regaining profiles of ε(r) is estimated using the atmospheric situation of a pure atmosphere and an extended smoke cloud arising from forest fires as an example. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 4, pp. 522–527, July–August, 2007.     

Determination of effective atomic numbers and effective electron densities for Cu/Zn alloy

The mass attenuation coefficients, total interaction cross-sections, effective atomic numbers, effective electron densities and photon mean free paths of the Cu/Zn alloy were determined on the basis of the mixture rule at 356, 511, 662, 835 and 1275 keV gamma-ray energies. The gamma-rays were detected by using an ordinary NaI(Tl) scintillation detection system with a resolution of 10.2% at 662 keV.It was observed that the mixture rule is a suitable method for determination of these parameters. The effective atomic numbers and effective electron densities tend to be almost constant as a function of energy. There is good agreement between experiment and theory, calculated by WinXCom.     

A comparative study of gamma-ray interaction and absorption in some building materials using Zeff-toolkit

The gamma-ray shielding behaviour of a material can be investigated by determining its various interaction and energy-absorption parameters (such as mass attenuation coefficients, mass energy absorption coefficients, and corresponding effective atomic numbers and electron densities). Literature review indicates that the effective atomic number (Z_eff) has been used as extensive parameters for evaluating the effects and defect in the chosen materials caused by ionising radiations (X-rays and gamma-rays). A computer program (Z_eff-toolkit) has been designed for obtaining the mean value of effective atomic number calculated by three different methods. A good agreement between the results obtained with Z_eff-toolkit, Auto_Z_eff software and experimentally measured values of Z_eff has been observed. Although the Z_eff-toolkit is capable of computing effective atomic numbers for both photon interaction (Z_eff,PI) and energy absorption (Z_eff,En) using three methods in each. No similar computer program is available in the literature which simultaneously computes these parameters simultaneously. The computed parameters have been compared and correlated in the wide energy range (0.001–20?MeV) for 10 commonly used building materials. The prominent variations in these parameters with gamma-ray photon energy have been observed due to the dominance of various absorption and scattering phenomena. The mean values of two effective atomic numbers (Z_eff,PI and Z_eff,En) are equivalent at energies below 0.002?MeV and above 0.3?MeV, indicating the dominance of gamma-ray absorption (photoelectric and pair production) over scattering (Compton) at these energies. Conversely in the energy range 0.002–0.3?MeV, the Compton scattering of gamma-rays dominates the absorption. From the 10 chosen samples of building materials, 2 soils showed better shielding behaviour than did other 8 materials.     

变系数Burgers方程的分类及相似解(英文)

应用经典李群理论考虑了描述非平面冲击波形成和衰减现象的(1 1)维变系数Burgers方程,得到该方程的群分类及相应的对称.对于某些具体形式的色散项系数a(t)和非线性项系数b(t),给出了对应方程的对称约化及相似解.本文在已有基础上给出了方程新的显式解.这些解对于研究某些复杂的物理现象,以及验证数值求解法则的可行性有重要的意义.     

变系数Whitham-Broer-Kaup方程组的对称、约化及精确解

利用修正的Clarkson-Kruskal直接法对变系数Whitham-Broer-Kaup(VCWBK)方程组进行等价转化,建立了VCWBK方程组与常系数WBK方程组解之间的关系,并得到了常系数WBK方程组的一些对称和相似约化.借助辅助函数法得到了VCWBK方程组的一些新精确解,包括有理函数解、双曲函数的解、三角函数解和Jacobi椭圆函数解.     

Diamagnetic susceptibility of some organic compounds

The diamagnetic susceptibilities of four aromatic compounds of known structure have been measured and the principal molecular susceptibilities have been deduced from these, knowing the molecular orientations. The anisotropy of the substituted benzene is less than that of the unsubstituted benzene. The delocalization term is greater for molecules with stronger hydrogen bonds.     

Induced quasicrystallinity of solutions of organic compounds

Using the method of optical probing, we investigated the effect exerted by the concentration of the substance and the temperature of the solution on the spectral behavior of the difference in the refractive indices of ordinary and extraordinary waves Δn=n_o−n_e of excited solutions of Rhodamine 6G and 3,6-tetramethyldiaminophthalimide in glycerin. We established that laser-excitation-induced quasicrystallinity of the indicated solutions in probing in the fluorescence band, which is characterized by the magnitude of the difference between the refractive indices Δn, increases with increase in the concentration of the substance. This increase in the crystallinity of the system with increase in the concentration of the substance (the activator) is possible up to the instant of the appearance of intermolecular interaction of the molecules. To whom correspondence should be addressed. Reported at the Second International Scientific and Technical Conference on Quantum Electronics, Minsk, November 23–25, 1998. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 672–674, September–October, 1999.     

大气气溶胶消光特性和折射率的测量

介绍了一种综合利用能见度仪、微脉冲激光雷达和光学粒子计数器测量大气气溶胶折射率的新方法。首先使用能见度仪和激光雷达测量出大气气溶胶的消光系数和消光后向散射比,然后使用粒子计数器测量出粒子谱分布,结合气溶胶粒子折射率,根据球形粒子的米（Mie）散射理论,可以得到气溶胶消光系数和消光后向散射比。通过分析消光系数、消光后向散射比、粒子谱分布和折射率之间的关系,结合已知的消光系数和消光后向散射比,反演出大气气溶胶粒子的折射率。     

Measurement of mass attenuation coefficients in some Cr,Co and Fe compounds around the absorption edge and the validity of the mixture rule

The total mass attenuation coefficients for elements Cr, Co and Fe and compounds CrCl₂, CrCl₃, Cr₂(SO₄)₃K₂SO₄·24H₂O, CoO, CoCl₂, Co(CH₃COO)₂, FePO₄, FeCl₃·6H₂O, Fe(SO₄)₂NH₄·12H₂O were measured at different energies between 4.508 and 14.142 keV using secondary excitation method. Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr were chosen as secondary exciters. 59.5 keV γ-rays emitted from a ²⁴¹Am annular source were used to excite a secondary exciter and K_α(K-L₃, L₂) lines emitted by the secondary exciter were counted by a Si(Li) detector with a resolution of 160 eV at 5.9 keV. It was observed that mixture rule method is not a suitable method for determination of the mass attenuation coefficients of compounds, especially at an energy that is near the absorption edge. The obtained values were compared with theoretical values.      

A new method of new exact solutions and solitary wave-like solutions for the generalized variable coefficients Kadomtsev——Petviashvili equation

Using the solution of general Korteweg--de Vries (KdV) equation, the solutions of the generalized variable coefficient Kadomtsev--Petviashvili (KP) equation are constructed, and then its new solitary wave-like solution and Jacobi elliptic function solution are obtained.