bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic Ferromagnetism and Antiferromagnetism of 4-Methacryloyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl and 4-Acryloyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl
Authors: Sugimoto Hiroyuki , Aota Hiroyuki , Harada Akira , Morishima Yotaro , Kamachi Mikiharu , Mori Wasuke , Kishita Michihiko , Ohmae Norihiro , Nakano Motohiro , Sorai Michio 
Published: March 2006

Abstract
The temperature dependence of the magnetic susceptibilities for 4-methacryloyloxy- and 4-acryloyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl (MOTMP and AOTMP, respectively) was measured. Intermolecular magnetic coupling in these radicals was changed from antiferromagnetic to ferromagnetic by substituting hydrogen at α-position with a methyl group. A magnetic phase transition for MOTMP was observed at 0.14 K in the measurement of the temperature dependence of heat capacity. The circumstantial evidences support that the ordered state is of ferromagnet.
A Novel Laser-induced Synthesis of 1,1-Dichloroethylene from 1,1-Dichloroethane
Authors: Oshima Yoshito , Iguchi Kayoko , Tominaga Hiro-o , Koda Seiichiro 
Published: March 2006

Abstract
The laser-induced photochlorination of 1,1-dichloroethane followed by its dehydrochlorination has been examined in a flow reactor under normal pressure at 25–200 °C, which has been proved to be a novel direct synthesis of vinylidene chloride.
197Au Mössbauer Spectroscopic Study of the Ternary Systems (Ag,Au)2X (X = S and Se)
Authors: Sakai Hiroshi , Ando Manabu , Ichiba Sumio , Maeda Yutaka 
Published: March 2006

Abstract
197Au Mössbauer spectroscopy has been applied for the low-temperature β-phases of ternary systems, Ag2−xAuxX (X = S, and Se; x = 0.2 and 0.5). The nature of linear X–Au–X bonds present in these systems is discussed on the basis of the Mössbauer data and the bond distances.
Micellar Activation of Nucleophilic Cu2+-complexes of Surfactant Imidazole Ligands by Co-surfactants for the Hydrolysis of p-Nitrophenyl Picolinate. Importance of the Charge Site on Surfactant Ligand
Authors: Ogino Kenji , Yoshida Toshiharu , Nishi Kazuyoshi , Fujita Tsunehisa , Tagaki Waichiro 
Published: March 2006

Abstract
The micellar activation of the nucleophilic Cu2+-complexes of four surfactant imidazole ligands has been examined for the hydrolysis of p-nitrophenyl picolinate. A dramatic difference in the effect of co-surfactant was observed between the ligands having a charged group at the polar terminal and those having it at the inner site apart from the imidazole head group.
Chemistry of Benzopentathiepin. Formation of 2-Imino-1,3-benzodithioles from Alkyl or Aryl Isochalcogenocyanates with Benzopentathiepin
Authors: Sato Ryu , Yamaichi Shizuko 
Published: March 2006

Abstract
Various 2-imino-1,3-benzodithioles were synthesized in good yields by the reaction of alkyl or aryl isochalcogenocyanates, R–N=C=X (X = S or Se), with benzopentathiepin in the presence of triethylamine.
1H-NMR Spectroscopic Studies on the Ruthenocene and Its Salts
Authors: Watanabe Masanobu , Sano Hirotoshi 
Published: March 2006

Abstract
Temperature dependence of 1H-NMR spectra of a system containing ruthenocene and ruthenoceniumX+Y− salts (X; Cl, Br, I and Y; PF6, BF4, I3) in 1:1 molar ratio indicates the presence of intermolecular electron transfer between the ruthenocene and ruthenocenium species associated with an exchange of X atoms between the RuIICp2 molecules and RuIVCp2X+ cations.
New Lumazines from the Marine Polychaete, Odontosyllis undecimdonta
Authors: Inoue Shoji , Okada Kunisuke , Tanino Hideo , Kakoi Hisae , Ohnishi Yoshiko , Horii Naojiro 
Published: March 2006

Abstract
6-β-Methoxypropionyl-3-methyllumazine and 6-β-methoxypropionyl-1,3-dimethyllumazine, and 6-β-hydroxypropionyl-3-methyllumazine have been newly isolated from the swimming polychaete, Odontosyllis undecimdonta.
Intramolecular Hydrogen Migration of Geometrically Constrained 3,3-Diphenyl-2-t-butyloxaziridine
Authors: Kawamura Yasuhiko , Tsukayama Masao , Hayashi Shuzo , Horie Tokunaru 
Published: March 2006

Abstract
Thermolysis of 3,3-diphenyl-2-t-butyloxaziridine gave benzophenone oxime and isobutylene via the C–O bond fission followed by the intramolecular synchronous hydrogen migration from the t-butyl group without the intervention of the corresponding nitrone.
The Benzimidazole Dye Hoechst 8208 Intercalates into DNA
Authors: Kubota Yukio , Nakamura Hiroyuki 
Published: March 2006

Abstract
The interaction of the benzimidazole dye Hoechst 8208 (H8208) with DNA has been studied by optical, hydrodynamic, and 1H NMR techniques. All of the results clearly indicate that H8208 intercalates between successive DNA base pairs.
Heck-type Reaction of lodotrimethylsilane with Olefins Affording Alkenyltrimethylsilanes
Authors: Yamashita Hiroshi , Kobayashi Toshi-aki , Hayashi Teruyuki , Tanaka Masato 
Published: March 2006

Abstract
lodotrimethylsilane reacted with styrene derivatives in the presence of triethylamine and a palladium catalyst to give β-styrylsilanes.
Chlorination of Benzene with L-Zeolite Catalyst in the Presence of Oxygen and Various Solvents
Authors: Nakamura Tadashi , Shinoda Kiyonori , Yasuda Kensei 
Published: March 2006

Abstract
Benzene was chlorinated by using L type zeolite into p-dichlorobenzene (p-DCB) in a high yield in the presence of 1,2-dichloroethane (EDC) and oxygen.
Selective Adsorption of Palladium(II), Platinum(IV), and Mercury(II) on a New Chitosan Derivative Possessing Pyridyl Group
Authors: Baba Yoshinari , Hirakawa Hiroyuki 
Published: March 2006

Abstract
Crosslinked N-(2-pyridylmethyl)chitosan was newly synthesized by crosslinking N-(2-pyridylmethylidene)chitosan of the intermediate compound before reducing it so that the adsorptive activity is not lowered by the crosslinking. The pyridylmethylchitosan selectively adsorbed palladium(II), platinum(IV), and mercury(II) over base metals from hydrochloric acid.
Radical Anion of Nitrile Ylide by Dual Beam Irradiation of 3-(4-Biphenylyl)-2H-azirine at Low Temperature
Authors: Ishida Akito , Naito Ikuo , Takamuku Setsuo 
Published: March 2006

Abstract
Photolysis and the successive γ-radiolysis of 3-(4-biphenylyl)-2H-azirine at 77 K resulted in the formation of a novel intermediate with an absorption maximum at 425 nm, which was produced by one-electron reduction of the nitrile ylide. The intermediate was also produced by photochemical ring-opening of the azirine radical anion.
β-Selective Epoxidation of Cholesterol Derivatives with Molecular Oxygen and Aldehyde Catalyzed by Manganese(II) Complex
Authors: Yamada Tohru , Imagawa Kiyomi , Mukaiyama Teruaki 
Published: March 2006

Abstract
In the presence of a catalytic amount of bis(dipivaloylmethanato)manganese(II) (= Mn(dpm)2), various cholesterol derivatives are smoothly converted into the corresponding β-epoxides in good to high yields with combined use of molecular oxygen and isobutyraldehyde. These stereoselectivities are the reversal of the cases using peracid such as mCPBA.
Photochemical α-Cleavage Reaction of Levoglucosenone
Authors: Yamada Shinji , Matsumoto Masakatsu 
Published: March 2006

Abstract
Irradiation of levoglucosenone having a 6-membered cyclic α,β-unsaturated ketone structure with a high pressure mercury arc stereoselectively produced (Z)-β,γ-unsaturated acid derivatives. The mechanism of the formation of these products is explained in terms of the α-cleavage reaction which is scarcely observed in the photochemical reaction of α,β-unsaturated ketones.
Identification of Pyrolysis Reaction Model of Linear Low Density Polyethylene (LLDPE)
Authors: Kim Seungdo , Kavitha D 
Published: March 2006

Abstract
This paper described how to estimate the Arrhenius parameters as well as the pyrolysis reaction model of LLDPE from isothermal kinetic data. We used a custom-made thermobalance that is capable of monitoring a weight decrease with time under pure static condition and performed six isothermal kinetic experiments at 713, 718, 723, 728, 733, and 738 K that were chosen within a temperature range (710–740 K) where main decompositions were observed from non-isothermal kinetic results. Comparing experimental reduced-time-plots (RTPs) with theoretical ones, the pyrolysis reaction model of LLDPE is accounted for by “Avrami–Erofeev” model in the investigated temperature region, allowing its functional form to be 2(1 − α)[−ln(1 − α)]1/2. It is, hence, expected that the reaction order model adopted by the previous studies without verification is inappropriate to represent the pyrolysis reaction model of LLDPE. Bubble nucleation may be a major pyrolysis reaction mechanism of LLDPE. As heat is applied, the LLDPE is melted. Volatiles may be accumulated inside the melt until reaching a critical concentration where bubble nucleation sets forth. The rates of heat, mass, or momentum transfer in the LLDPE melt and its physico-chemical properties (especially viscosity) play an important role in characterizing the thermal decomposition kinetics of LLDPE.
Eulerian backtracking of atmospheric tracers. I: Adjoint derivation and parametrization of subgrid‐scale transport
Authors: Hourdin F. , Talagrand O. 
Published: March 2006

AbstractThe problem of identification of sources of atmospheric tracers is most classically addressed through either Lagrangian backtracking or adjoint integration. On the basis of physical considerations, the retro‐transport equation, which is at the basis of Lagrangian backtracking, can be derived in a Eulerian framework as well. Because of a fundamental time symmetry of fluid transport, Lagrangian or Eulerian backtracking can be used for inverting measurements of the concentration of an atmospheric tracer. The retro‐transport equation turns out to be the adjoint of the direct transport equation, with respect to the scalar product defined by integration with respect to air mass. In the present paper, the exact equivalence between the physically‐derived retro‐transport and adjoint equations is proved. The transformation from the direct to the retro‐transport equation requires only simple transformations. The sign of terms describing explicit advection is changed. Terms describing linear sources or sinks of tracers are kept unchanged. Terms representing diffusion by unresolved time‐symmetric motions of the transporting air are also unchanged. This is rigorously shown for turbulent eddy‐diffusion or mixing length theory. The case of subgrid‐scale vertical transport by non‐time‐symmetric motions of air is studied using the example of the Tiedtke mass‐flux scheme for cumulus convection. The retro‐transport equation is then obtained by simply inverting the roles of updraughts and downdraughts, as well as of entrainment and detrainment. Conservation of mass of the transporting air is critical for all those properties to hold. Copyright © 2006 Royal Meteorological Society
Eulerian backtracking of atmospheric tracers. II: Numerical aspects
Authors: Hourdin F. , Talagrand O. , Idelkadi A. 
Published: March 2006

AbstractIn Part I of this paper, a mathematical equivalence was established between Eulerian backtracking or retro‐ transport, on the one hand, and adjoint transport with respect to an air‐mass‐weighted scalar product, on the other. The time symmetry which lies at the basis of this mathematical equivalence can however be lost through discretization. That question is studied, and conditions are explicitly identified under which discretization schemes possess the property of time symmetry. Particular consideration is given to the case of the LMDZ model. The linear schemes used for turbulent diffusion and subgrid‐scale convection are symmetric. For the Van Leer advection scheme used in LMDZ, which is nonlinear, the question of time symmetry does not even make sense. Those facts are illustrated by numerical simulations performed in the conditions of the European Transport EXperiment (ETEX). For a model that is not time‐symmetric, the question arises as to whether it is preferable, in practical applications, to use the exact numerical adjoint, or the retro‐transport model. Numerical results obtained in the context of one‐dimensional advection show that the presence of slope limiters in the Van Leer advection scheme can produce in some circumstances unrealistic (in particular, negative) adjoint sensitivities. The retro‐transport equation, on the other hand, generally produces robust and realistic results, and always preserves the positivity of sensitivities. Retro‐transport may therefore be preferable in sensitivity computations, even in the context of variational assimilation. Copyright © 2006 Royal Meteorological Society
Diagnosis and tuning of observational error in a quasi‐operational data assimilation setting
Authors: Chapnik Bernard , Desroziers Gerald , Rabier Florence , Talagrand Olivier 
Published: March 2006

AbstractDesroziers and Ivanov proposed a method to tune error variances used for data assimilation. The implementation of this algorithm implies the computation of the trace of certain matrices which are not explicitly known. A method proposed by Girard, allowing an approximate estimation of the traces without explicit knowledge of the matrices, was then used. This paper proposes a new implementation of the Desroziers and Ivanov algorithm, including a new computation scheme for the required traces. This method is compared to Girard's in two aspects: its use in the implementation of the tuning algorithm, and the computation of a quantification of the observation impacts on the analysis known as Degrees of Freedom for Signal. Those results are illustrated by studies utilizing the French data assimilation/numerical weather‐prediction system ARPEGE. The impact of a first quasi‐operational tuning of variances on forecasts is shown and discussed. Copyright © 2006 Royal Meteorological Society
Linear dynamics of non‐symmetric perturbations in geostrophic horizontal shear flows
Authors: Kalashnik M. V. , Mamatsashvili G. R. , Chagelishvili G.D. , Lominadze J. G. 
Published: March 2006

AbstractThe linear dynamics of non‐symmetric wave and vortex mode perturbations in spectrally stable geostrophic zonal flows with a constant horizontal shear along the meridional direction, when a fluid is incompressible and stratified, is investigated. Specific features of these dynamics are closely related to the non‐normality of the linear operators governing perturbation evolution in shear flows and are well interpreted in the framework of the non‐modal approach—by tracing the linear dynamics of spatial Fourier harmonics of perturbations in time. If the Rossby number Ro<1, there occurs an algebraic (asymptotically linear) amplification of non‐symmetric shear internal waves. It is shown that at Ro>1, in addition, there takes place an exponential/explosive transient growth of the waves that precedes the time interval of algebraic amplification. We also describe the evolution of pure vortex mode perturbations imposed initially on the mean flow. It is shown that at Ro∼1, pure vortex (aperiodic) perturbations are able to gain basic flow energy and then generate non‐symmetric shear internal waves. The studied linear phenomena are specific to geostrophic zonal flows and cast doubt on the filtering of fast wave perturbations in the traditional quasi‐geostrophic models of geophysical hydrodynamics. Copyright © 2006 Royal Meteorological Society
Sea‐breeze‐induced mass transport over complex terrain in south‐eastern France: A case‐study
Authors: Bastin S. , Drobinski P. 
Published: March 2006

AbstractThe structure and evolution of the sea breeze in southern France on 25 June 2001 is investigated experimentally and numerically. This study shows how interactions between the sea breeze, the synoptic flow and the complex terrain affect the sea‐breeze structure, and quantifies and discusses the air‐mass transport associated with the sea‐breeze circulation. The analysis of the front propagation and the associated turbulent kinetic energy budget allows four distinct stages of sea‐breeze front evolution to be identified. Quantification of the horizontal and vertical air‐mass fluxes is related to these four stages: the horizontal advection is directly linked to the intensity of the sea‐breeze flow. Two main mechanisms contribute to the vertical export within the free troposphere: anabatic upslope winds which are intensified by the sea‐breeze flow and frontogenesis at the sea‐breeze front which generates turbulence and mixing and upward motion. Copyright © 2006 Royal Meteorological Society
Daytime convective development over land: A model intercomparison based on LBA observations
Authors: Grabowski W. W. , Bechtold P. , Cheng A. , Forbes R. , Halliwell C. , Khairoutdinov M. , Lang S. , Nasuno T. , Petch J. , Tao W.‐K. , Wong R. , Wu X. , Xu K.‐M. 
Published: March 2006

AbstractThis paper investigates daytime convective development over land and its representation in single‐column models (SCMs) and cloud‐resolving models (CRMs). A model intercomparison case is developed based on observations of the diurnal cycle and convection during the rainy season in Amazonia. The focus is on the 6 h period between sunrise and early afternoon which was identified in previous studies as critical for the diurnal cycle over summertime continents in numerical weather prediction and climate models. This period is characterized by the formation and growth of a well‐mixed convective boundary layer from the early morning temperature and moisture profiles as the surface sensible‐ and latent‐heat fluxes increase after sunrise. It proceeds with the formation of shallow convective clouds as the convective boundary layer deepens, and leads to the eventual transition from shallow to deep precipitating convection around local noon. To provide a benchmark for other models, a custom‐designed set of simulations, applying increasing in time computational domain and decreasing spatial resolution, was executed. The SCMs reproduced the previously identified problem with premature development of deep convection, less than two hours after sunrise. The benchmark simulations suggest a possible route to improve SCMs by considering a time‐evolving cumulus entrainment rate as convection evolves from shallow to deep and the cloud width increases up to an order of magnitude. The CRMs featuring horizontal grid length around 500 m are capable of capturing the qualitative aspects of the benchmark simulations, but there are significant differences among the models. Two‐dimensional CRMs tend to simulate too rapid a transition from shallow to deep convection and too high a cloud cover. Copyright © 2006 Royal Meteorological Society
A new look at the midlatitude–MJO teleconnection in the northern hemisphere winter
Authors: Kim Baek‐Min , Lim Gyu‐Ho , Kim Kwang‐Yul 
Published: March 2006

AbstractThe midlatitude to Madden–Julian (MJO) teleconnection in the northern hemisphere wintertime was investigated using twenty years of outgoing long‐wave radiation and National Center for Atmospheric Research/National Centers for Environmental Prediction re‐analysis data. It is revealed through empirical orthogonal functions and regression analyses that the tropical upper‐level divergence (convergence) associated with enhanced (reduced) tropical convection has a subtropical counterpart of upper‐level convergence (divergence). As the convective region of MJO moves eastward from the Indian Ocean to the western Pacific, the divergent circulation connecting the Tropics and subtropics moves eastward. From an analysis of vertical motion diagnosed by the generalized omega equation, it was revealed that the position of the subtropical Rossby gyres of the MJO with respect to the Asian‐Pacific jet was the most important factor affecting the existence of the localized divergence (convergence) and associated lower‐level vertical motion in the subtropics. As the subtropical Rossby gyres pass by the longitudinal position of the Asian‐Pacific jet, vertical motion occurs to meet the balance required by quasi‐geostrophic theory. Since this anomalous vertical motion is large enough to cause convection at that region, the diabatic heating process reinforces the vertical motion. Furthermore, other dynamical processes neglected in quasi‐geostrophic theory are activated and contribute to the vertical motion balancing the diabatic heating. As a result of the vertical motion near the jet entrance region in the subtropics, the vorticity advection by vertical wind and the tilting of vorticity become important. Since these two terms are similar in shape and magnitude, they reinforce each other during the development phase of the midlatitude–MJO teleconnection. Combining these two terms, we define the baroclinic jet source (BJS). In order to evaluate the BJS as a source for the midlatitude–MJO teleconnection, a numerical experiment is carried out. The linear barotropic model is forced by only two terms, yet the model captured clearly the main feature of the midlatitude–MJO teleconnection. Copyright © 2006 Royal Meteorological Society
Comparison of the Met Office's surface exchange scheme, MOSES, against field observations
Authors: Rooney G. G. , Claxton B. M. 
Published: March 2006

AbstractResults are presented from a comparison of the Met Office Surface Exchange Scheme (MOSES) with observational data. A stand‐alone version of MOSES is used which can be forced directly with observations rather than model output. The forcing data consist of near‐surface measurements of incident radiation, wind speed, temperature, pressure, humidity and precipitation, and the model output is compared with measured surface fluxes of sensible and latent heat and with soil moisture at several levels below the surface. The dataset spans four years and comes from a grassland site with a shallow water table, the Met Office Research Unit at Cardington in Bedfordshire, UK.The performance of the model is assessed in response to the variation of some key parameters and parametric functions. The model calculation of atmospheric fluxes is found to be robust to variations in the soil thermal properties, and it is shown that there is little overall improvement in model performance as the vegetation height and ratio of scalar to momentum roughness lengths are varied over a range of possible values. The calculation of atmospheric moisture flux and soil‐moisture profile is assessed using two constant subsurface profiles of saturated hydraulic conductivity and one profile which decreases with depth. It is found that the last of these can produce a more physically accurate profile of soil moisture, but with current model tuning this produces less accurate values of atmospheric moisture flux. The model results compare favourably with those of a force–restore model. Copyright © 2006 Crown copyright
On the nonlinear interaction between global teleconnection patterns
Authors: Khokhlov V. N. , Glushkov A. V. , Loboda N. S. 
Published: March 2006

AbstractProcesses of nonlinear interaction between teleconnection patterns are addressed. Evidence of chaotic behaviour for the relationship between the Arctic Oscillation (AO), the Southern Oscillation (SO), and the Antarctic Oscillation (AAO) is examined using cross‐redundancy and Granger causality. The analysis is carried out for three epochs of the twentieth century, during which different trends of global temperature were observed. To study the influence of low‐frequency variations, a wavelet decomposition is applied. Presented results display many well‐known features of feedbacks between climate change and observed trends in the indices of teleconnection patterns. By using wavelet detail components, some behaviour is revealed as being particularly pure. At the same time, some findings require considerable further work, especially the apparent nonlinear interaction between the AO and the AAO. Our results are encouraging for the prospects of a useful model describing climate changes at the decadal and centurial time‐scales. Copyright © 2006 Royal Meteorological Society