Analysis of Off-Axial Optical Systems (1)

We have established a new method of aberration analysis for off-axial optical systems which are generalized concepts of co-axial optical systems, by introducing two kinds of newly defined 4-element vectors and expanding these vectors with the help of tensor algebra. In this method, since aberration properties are represented in tensor form, we can easily formulate the aberration relations between different azimuths. We can then evaluate the azimuth dependence of aberration properties in greater detail by separating them into inherent optical properties parts, which are independent of azimuths, and the paraxial ray-tracing part, which includes the expression of the evaluation azimuth.     

The ground state well depth position Rm of Van der Waals molecules and the spectral line shapes

As the ground state potential curve is strongly related to spectral line shapes, the minumum position of the ground state potential is obtained from the experiemental absorption profile k(Δν, T) at high density of the radiating atoms. The temperature dependence of the absorption processes of Hg and Cd lines 253.65 and 326.1 nm, respectively perturbed by inert gases (Xe, Kr, Ar and Ne) had been carefully studied over a wide spectral range. Using the point of the maximum temperature dependence Δν_m in each case, we are able to calculate the position of the ground state potential R_m using a simple formula.     

热熔合反应合成超重核产生截面的同位素依赖性

通过在形成超重核的重离子俘获和熔合过程中引入位垒分布函数的方法对双核模型做了进一步发展. 超重核形成过程中的俘获、熔合和蒸发3个阶段分别采用了半经验的耦合道模型、数值求解主方程和统计蒸发模型的方法来描述. 计算了近年来Dubna小组利用热熔合反应⁴⁸Ca(²⁴³Am, 3n—5n)^288—286115和⁴⁸Ca(²⁴⁸Cm, 3n—5n)^293—291116合成超重新核素的蒸发余核激发函数. 系统分析了⁴⁸Ca轰击锕系元素U,Np,Pu,Am,Cm合成超重核Z=112—116产生截面的同位素依赖性. 给出了合成超重新核素最佳的弹靶组合和入射能量, 即有最大的超重核产生截面. 计算说明, 壳修正能和中子分离能是影响超重核生成截面产生同位素依赖性的主要因素.     

Multivariate risk models under heavy‐tailed risks

In this paper, we consider four common types of ruin probabilities for a discrete‐time multivariate risk model, where the insurer is assumed to be exposed to a vector of net losses resulting from a number of business lines over each period. By assuming a large initial capital for the risk model and regularly varying distributions for the net losses, we establish some interesting asymptotic estimates for ruin probabilities in terms of the upper tail dependence function of the net loss vector. Our results insightfully characterize how the dependence structure among the individual net losses affect the ruin probabilities in an asymptotic sense, and more importantly, from our main results, explicit asymptotic estimates for those ruin probabilities can be obtained via specifying a copula for the net loss vectors. Copyright © 2013 John Wiley & Sons, Ltd.     

STUDY ON THE CONCENTRATION DEPENDENCE OF ORIENTATION OF POLYSTYRENE ON SILVER BY THE SERS TECHNIQUE*

Polystyrene films were adsorbed onto a silver surface from dichloromethane solutions with concentrations of 0.1 to12 wt%, and then studied by the surface enhanced Raman technique. A critical concentration for coil interpenetration wasobserved.     

Triplet-triplet transfer of electronic energy upon nonequilibrium vibrational excitation of triplet molecules

The specific features of the triplet-triplet (T-T) transfer of electronic excitation energy in a gas phase upon nonequilibrium vibrational excitation of the triplet molecules of a donor were studied for an anthraquinone-diacetyl donor-acceptor pair using the time-resolved slow fluoresence of anthraquinone and sensitized phosphorescence of diacetyl. It is shown that in the gas phase, which allows regular control of the number of collisions, competition between the processes of T-T transfer and intermolecular vibrational relaxation is observed for nanosecond time resolution. The T-T transfer rate for the molecular system investigated exceeded the rate of intermolecular vibrational relaxation k_V in the triplet state T₁ of the donor. The effectiveness of the T-T transfer of energy by vibrationally excited molecules turned out to be higher than the effectiveness of transfer by thermalized ones, but even the highest of them was much less than unity. An increase in the equilibrium temperature of vapors led to a decrease in the effectiveness of transfer for both vibrationally excited and thermalized triplet molecules, thus indicating the importance of the collisional complex in the intermolecular process studied. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 4, pp. 474–479, July–August, 2000.     

Radiation-induced defects in sucrose single crystals, revisited: a combined electron magnetic resonance and density functional theory study

The results are presented of an electron magnetic resonance analysis at 110 K of radiation-induced defects in sucrose single crystals X-irradiated at room temperature, yielding a total of nine (1)H hyperfine coupling tensors assigned to three different radical species. Comparisons are made with results previously reported in the literature. By means of electron paramagnetic resonance and electron nuclear double resonance temperature variation scans, most of the discrepancies between the present 110 K study and a previous 295 K study by Sagstuen and co-workers are shown to originate from the temperature dependence of proton relaxation times and hyperfine coupling constants. Finally, radical models previously suggested in the literature are convincingly refuted by means of quantum chemical density functional theory calculations.     

Volumetric study on the inclusion complex formation of α- and β-cyclodextrin with 1-alkanols at different temperatures

The partial molar volumes (V_a) of 1-alkanols (carbon number, m=5, 6, 7) in - and -cyclodextrin (CD) solutions at 5.00 mmol kg^–1 have been determined as a function of alkanol concentration (C_a) between 293.2 and 308.2 K by using a dilatometer. It has been observed that with an increase in C_a, V_a increased in -CD solution but decreased in -CD solution, asymptotically to a value of V_a in CD-free water. The dependence of V_a on C_a provided the binding constant (K) of 1:1 complex, the volume change in complex formation, and the partial molar volume of complex itself. The complex formation mechanism has been discussed on the basis of these values and their carbon number dependences in the respect of geometric behavior, hydrophobic interaction, and van der Waals interaction. It is concluded that the CD cavity in water is not rigid but flexible for fitting in nicely with guest molecule.     

Conductivity of irradiated Kapton in relation to energy loss of ions and electrons

Abstract

We have studied the effects of 2.5 MeV electron irradiation and ion (C, N, F, Si and Kr) bombardment on the electrical conductivity of a polyimide (Kapton-H) with ion energies ranging between 320 keV (N) and 1.25 GeV (Kr). In this wide range of situations we have tried to sort out the respective effects of nuclear and electronic excitation energy losses.

For all ion irradiation the conductivity is found to scale with the electronic excitation absorbed dose: i.e. a power law of conductivity versus absorbed dose with an exponent around 9 is observed. At a given absorbed dose (in Gray units) the efficiency of each ion to enhance conductivity is found to be proportional to the electronic energy loss; electrons are much less efficient than ions and thus collective excitations are required to achieve this process.

The nuclear energy loss can perhaps play some role at conductivities higher than 100 Ω^?1 m^?1, but its effects are negligible in the range explored here.     

Temperature Dependence of the Efficiency of Collisional Transfer of Vibrational Energy in Mixtures of Vibrationally Excited Triplet Molecules with Foreign Gases

By the pressure dependences of the decay rates of delayed fluorescence activated by vibrational excitation of triplet molecules of benzophenone and anthraquinone, the efficiencies of collisional transfer of vibrational energy (V–V-transfer) in the vibrational quasi-continuum of the triplet state have been estimated. It is shown that the efficiencies of the process in mixtures with foreign gases increase with increasing dipole moment and polarizability of colliding molecules. In the temperature range 433–513 K, we obtained an inverse temperature dependence of the V–V-transfer efficiency, which is satisfactorily described by empirical relations taking into account long-range attractive forces. The results obtained point to the determining role of long-range attractive forces in quasi-resonance V–V-transfer of vibrational energy by molecules excited in vibrational quasi-continuum.