Weighted premium calculation principles

A prominent problem in actuarial science is to define, or describe, premium calculation principles (pcp’s) that satisfy certain properties. A frequently used resolution of the problem is achieved via distorting (e.g., lifting) the decumulative distribution function, and then calculating the expectation with respect to it. This leads to coherent pcp’s. Not every pcp can be arrived at in this way. Hence, in this paper we suggest and investigate a broad class of pcp’s, which we call weighted premiums, that are based on weighted loss distributions. Different weight functions lead to different pcp’s: any constant weight function leads to the net premium, an exponential weight function leads to the Esscher premium, and an indicator function leads to the conditional tail expectation. We investigate properties of weighted premiums such as ordering (and in particular loading), invariance. In addition, we derive explicit formulas for weighted premiums for several important classes of loss distributions, thus facilitating parametric statistical inference. We also provide hints and references on non-parametric statistical inferential tools in the area.     

A redox-active two-dimensional coordination polymer: preparation of silver and gold nanoparticles and crystal dynamics on guest removal

A two-dimensional (2D) square-grid coordination polymer, {[Ni(cyclam)]2[BPTC]}n.2nH2O (1), has been assembled from [Ni(cyclam)](ClO4)2 (cyclam = 1,4,8,11-tetraazacyclotetradecane) and H4BPTC (H4BPTC = 1,1'-biphenyl-2,2',6,6'-tetracarboxylic acid) in H2O/MeOH (2.5:1, v/v) in the presence of triethylamine. When solid 1 was immersed in the EtOH solutions of AgNO3 (1.3 x 10(-1) M) and NaAuCl4.2H2O (3.4 x 10(-2) M), respectively, for 5 min at room temperature, solids including Ag (3.7 +/- 0.4 nm, diameter) and Au (2 nm, diameter) nanoparticles were formed by the redox reactions between Ni(II) ions incorporated in 1 and metal ions, as evidenced by HRTEM images, EPR, and XPS spectra. When single-crystal 1 was heated at 180 degrees C under 10(-5) Torr for 24 h, it was transformed to dehydrated compound {[Ni(cyclam)]2[BPTC]}n (2) in the single-crystal-to-single-crystal manner. The X-ray crystal structure of 2 reveals extensive dynamic motions of the molecular components in response to guest removal, involving rotation of the carboxylate and macrocycle, swing of the biphenyl, and bending of the macrocyclic coordination plane toward the carboxylate plane, which reduces the interlayer distance.     

Theoretical explorations on the armchair BN nanotube with defects

A systematic study of armchair boron nitride nanotubes (BNNTs) with defects has been carried out within density functional theory. The effect brought by the defects is localized. The defect sites have major contribution to the frontier molecular orbital and change the conductivity of the BNNTs. The defect sites are reactive centers. The substitution of boron with carbon enhances the field emission of the tubes. Doping or vacancy defect creates active center on nanotubes, thus broadening the applications of nanotubes in chemistry and material sciences through functionalization.     

Improving dispersion stability of zirconium hydroxide sol for preparing nano zirconia by the reverse precipitation

Zirconium hydroxide sol was prepared by the reverse precipitation method with ZrOCl₂ solution as raw material and the processing condition of the zirconium hydroxide sol was investigated. When the saturated absorption amount of the surfactant was 1.0?wt%, the pH value for the highest stability was shifted from 7.9 to 9.3 and the pH range for preparing stable zirconium hydroxide sol widened as 8.0-11.0. The suitable concentration of ZrOCl₂ solution for the efficient gelation keeping the high dispersion stability was investigated. The microwave drying was demonstrated to be suitable for preparation of nanoparticle. The characteristics of produced nano zirconia were discussed, which in results the shape of powder was spherical and the grain size was 35?nm at average with moderate dispersion.     

Flame-Flow Interaction in Premixed Turbulent Flames During Transient Head-On Quenching

This paper reports on experimental investigations of turbulent flame-wall interaction (FWI) during transient head-on quenching (HOQ) of premixed flames. The entire process, including flame-wall approach and flame quenching, was analyzed using high repetition rate particle image velocimetry (PIV) and simultaneous flame front tracking based on laser-induced fluorescence (LIF) of the OH molecule. The influence of convection upon flame structures and flow fields was analyzed qualitatively and quantitatively for the fuels methane (CH₄) and ethylene (C₂H₄) at ? = 1. For this transient FWI, flames were initialized by laser spark ignition 5 mm above the burner nozzle. Subsequently, flames propagated against a steel wall, located 32 mm above the burner nozzle, where they were eventually quenched in the HOQ regime due to enthalpy losses. Twenty ignition events were recorded and analyzed for each fuel. Quenching distances were 179 μm for CH₄ and 159 μm for C₂H₄, which lead by nondimensionalization with flame thickness to Peclet numbers of 3.1 and 5.5, respectively. Flame wrinkling and fresh gas velocity fluctuations proved flame and flow laminarization during wall approach. Velocity fluctuations cause flame wrinkling, which is higher for CH₄ than C₂H₄ despite lower velocity fluctuations. Lewis number effects explained this phenomenon. Results from flame propagation showed that convection dominates propagation far from the wall and differences in flame propagation are related to the different laminar flame speeds of the fuels. Close to the wall flames of both fuels propagate similarly, but experimental results clearly indicate a decrease in intrinsic flame speed. In general, the experimental results are in good agreement with other experimental studies and several numerical studies, which are mainly based on direct numerical simulations.     

Retention of Large Biological Molecules by Size-Exclusion Chromatography

Size-exclusion chromatography has been developed for the separation of large biological molecules including proteins, polymers, peptides, nucleic acids, and polysaccharide according to their molecular size. This study determined the retention factors for dextran (5, 25, 50, 270, 670, and 1100?kDa) and polysaccharides, such as fucoidan, alginic acid, and laminarin, in the size-exclusion chromatography stationary phase. In addition, the molecular weights and retention factor of three polysaccharides were calculated from the dextran standard curve. The largest retention factor was 4.26 using the size-exclusion chromatography columns (5?kDa dextran). The molecular weights of fucoidan, alginic acid, and laminarin were determined to be 250, 200, and 5 to 64?kDa, respectively.     

Kondesationen mit hydrazin-N,N′-dicarbonsäurediamidin,XXIII [1] fluorierte β-diketone als reaktionspartner

Application of a 30% aqueous potassium carbonate solution for the condensation of 1,2-hydrazinedicaboxamidine with 1,1,1-trifluoro-2,4-pentanedione leads to the formation of 4,4′-dimethyl-6,6′-bis(trifluoromethyl)-2,2′-hydrazopyrimidine, with 1,1,1-trifluoro-2,4-hexanedione to 4,4′-diethyl-6,6′-bis-(trifluoromethyl)-2,2′-hydrazopyrimidine. 2-Guanidinoamino-4-methyl-6-trifluoromethylpyridine formed as an intermediate in this reacton may be isolated, while 4-ethyl-2-guanidinoamino-6-trifluoromethylpyrimidine undergoes cyclization to yield 2-amino-5-ethyl-7-trifluoromethyl-s-triazolo[1,5-a]pyrimidine.     

Theoretical study of the Si2NO potential energy surface

The structures, spectroscopies, and stabilities of the doublet Si₂NO radical are explored at the density functional theory (DFT) and ab initio levels. Seventeen isomers are located, connected by 26 interconversion transition states. At the CCSD(T)/6‐311+G(2df)//QCISD/6‐311G(d)+ZPVE level, three low‐lying isomers are predicted, that is, one bent species SiNSiO 3 (5.1 kcal/mol) containing the important Si?N triple bonding and two four‐membered ring isomers including cyclic cSiNSiO 1 (0.0) with Si? Si cross‐bonding with C_2v symmetry and puckered cSiNSiO 1′ (11.9) with divalent carbene character. Three low‐lying isomers 1, 1′, and 3 have reasonable kinetic stabilities and might be observable either experimentally or astrophysically. The possible formation strategies of 1, 1′, and 3 in laboratory and in space are discussed in detail. The calculated vibrational frequencies and possible formation processes of 3 are consistent with recent experimental observations. In light of the fact that no cyclic nitrogen‐containing species have been detected in space, two cyclic isomers 1 and 1′ could be promising candidates. Furthermore, the bonding nature of three isomers 1, 1′, and 3 is analyzed. The calculated results are also compared with those of the analogue C₂NO radical. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007