bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal Structures and Magnetic Properties of d-pπ Organic Conductors, (EDT-TTF)4CoCl4(1,1,2-TCE)x and Related Materials
Authors: Mori Hatsumi , Sakurai Naoki , Tanaka Shoji , Moriyama Hiroshi 
Published: December 2003

Abstract
A new series of d-pπ organic conductors ((EDT-TTF)4CoX4(solvent)x [EDT–TTF = ethylenedithiotetrathiafulvalene; X = Cl, Br; solvent = 1,1,2–TCE (trichloroethane), CH2Cl2]) consists of anions including 3d localized spins and donors containing itinerant pπ electrons. The crystal and band structure analyses show that these salts have face-to-face regular donor stacking, the so-called β-type donor arrangement, and that the calculated Fermi surfaces are closed due to relatively large interchain interactions. Resistivity measurements show the metallic behaviors down to 80 K [(EDT-TTF)4CoCl4(1,1,2-TCE)x], 235 K [(EDT-TTF)4CoCl4(CH2Cl2)x], 110 K [(EDT-TTF)4CoBr4(1,1,2-TCE)x], and 190 K [(EDT-TTF)4CoBr4(CH2Cl2)x], respectively. Especially, for (EDT-TTF)4CoCl4(1,1,2-TCE)x, the ESR measurements indicate that the linewidth attributed to EDT-TTF+ increases and that the g-value decreases rapidly when the resistivity starts increasing below 80 K, owing to substantially the dipole–dipole interaction between pπ (EDT-TTF+)-3d (Co2+) spins. At around 33 and 20 K, the anomalies of the ESR linewidth have been observed, suggesting the instability of the pπ part.
The B1u and B2u Vibrational Modes Causing a D6h to D3h Transition in Benzene and in [18]- and [30]Annulenes
Authors: Yoshizawa Kazunari , Tachibana Masamitsu , Yamabe Tokio 
Published: December 2003

Abstract
Alternation of long and short carbon–carbon bonds in large cyclic polyenes are investigated from the point of view of vibrational analyses. [6(2n + 1)]Annulenes, where n is 0, 1, 2,···, are cyclic polyenes that can have planar bond-delocalized D6h or bond-localized D3h structures without severe nonbonded interactions. The B1u and B2u modes of vibration that potentially cause a D6h to D3h transition in benzene, [18]annulene, and [30]annulene are specifically discussed. The delocalized D6h structure is stable in benzene and [18]annulene, but not in [30]annulene. The D6h structure of [30]annulene has an imaginary B2u mode of 416i cm−1 that has relevance to the so-called Kekulé B2u mode of benzene. The D6h structure of [30]annulene is confirmed to be a transition state that leads to the equivalent D3h global minimum in both the forward and reverse directions.
Determination of Total Arsenic in Environmental and Geological Samples by Electrothermal Atomic Absorption Spectrometry Using a Tungsten Furnace after Solvent Extraction and Cobalt(III) Oxide Collection
Authors: Narukawa Tomohiro , Yoshimura Wataru , Uzawa Atsushi 
Published: December 2003

Abstract
A separation method, using solvent extraction and cobalt(III) oxide collection, has been studied for determining the total arsenic in environmental and geological samples by electrothermal atomic absorption spectrometry (ETAAS) using a tungsten furnace. After arsenic iodide was extracted into benzene, cobalt(III) oxide powder was added to the benzene solution to collect the extracted arsenic. The cobalt(III) oxide was separated from benzene by vacuum filtration and then suspended in 5 cm3 of water. The slurry was introduced into the tungsten furnace and the determination of arsenic was performed. The relative standard deviation of the proposed method at the 0.20 mg dm−3 arsenic level was 2.4% (n = 10). The calibration curve obtained with the proposed method was linear up to 0.50 mg dm−3 (5.00 ng/10 mm3), and the detection limit (3σ) was 12 μg dm−3 (0.12 ng/10 mm3). The present method was applied to the analysis of some environmental and geological standard reference materials, and the concentrations of total arsenic obtained by the present method were in good agreement with the certified values or the reference values of those samples.
Hydroxylation of Aliphatic Hydrocarbons with m-Chloroperbenzoic Acid Catalyzed by Electron-Deficient Iron(III) Porphyrin Complexes
Authors: Lim Mi Hee , Lee Yoon Jung , Goh Yeong Mee , Nam Wonwoo , Kim Cheal 
Published: December 2003

Abstract
The catalytic hydroxylation of aliphatic hydrocarbons by m-chloroperbenzoic acid (MCPBA) has been studied in the presence of elecrtron-deficient iron(III) porphyrin complexes. High yields of alcohol products were obtained with small amounts of ketone formation under mild reaction conditions. The stereospecificity and regioselectivity of the iron porphyrin complexes have been investigated in hydroxylation reactions as well. The hydroxylation of alkanes has been performed in the presence of isotopically 18O-labeled water, H218O, in order to understand the effects of the electronic nature of iron porphyrin complexes, the concentration of H218O, the C–H bond strength of alkanes, and the reaction temperature on the 18O-incorporation from the labeled water into alcohols. We found that the amounts of 18O incorporated into the alcohol products varied in the reactions; these results were interpreted with that the reaction of oxygen atom transfer from a high-valent iron oxoporphyrin complex to alkanes competes with that of oxygen atom exchange between the intermediate and labeled water that leads to 18O-incorporation from H218O into the alcohol products. Deuterium kinetic isotope effects (KIEs) in the alkane hydroxylations by the iron porphyrin complexes and MCPBA have been studied with a mixture of cyclohexane and cyclohexane-d12. The KIE values obtained in the reactions were found to depend significantly on the nature to the iron porphyrin complexes. The temperature dependence of kH/kD was also studied from −40 to 25 °C and the parameters of Arrhenius equation (i.e., the pre-exponential factor ratio, AH/AD, and the isotopic difference of C–H and C–D bond activation energies, Ea(D)–Ea(H)) were determined.
Synthesis and Photochemical Properties of Ruthenium–Cobalt and Ruthenium–Nickel Dinuclear Complexes
Authors: Komatsuzaki Nobuko , Himeda Yuichiro , Hirose Takuji , Sugihara Hideki , Kasuga Kazuyuki 
Published: December 2003

Abstract
Three dinuclear colmplexes, two Ru(II)–Co(III) and one Ru(II)–Ni(II) polypyridyl complexes, were prepared by the use of ethylene- and pentamethylene-linked bisphenanthroline as the bridging ligands. Their photochemical and electrochemical properties were examined. Each metal complex component was shown to be electronically insulated. Since the roles of the Ru(II) as a photosensitizer and the Co(III) or Ni(II) moiety as an electron acceptor were expected, a photocatalytic CO2 reduction experiment was carried out. The catalytic ability of the Ru(II)–Co(III) system was shown to be almost the same as the corresponding intermolecular systems with the improved CO/H2 selectivity, showing that the Co(III) polypyridyl complex was as effecticve as the Co(II) species for a catalytic center.
Solvent-Dependent Conformations of Cyclic Tetrapeptide. II
Authors: Tamaki Makoto , Yabu Mikihiro , Saeki Tomomi , Kaneko Ayako , Akabori Sadatoshi , Muramatsu Ichiro 
Published: December 2003

Abstract
The solvent-dependent conformations of cyclo(–δ-Ava–l-Pro–)2 were characterized by means of the 1H and 13H NMR, CD, and IR spectra. CD results in CH2Cl2, CH3CN, CH3OH, and H2O indicated that the change in polarity of the solvent induces a reversible change in the conformation of cyclo(–δ-Ava–l-Pro–)2, revealed by the decrease of the negative peak near to 230 nm and then by the gradual appearance of a negative trough near to 210 nm. The NMR data in CD3Cl, CD2Cl2, CD3CN, and CD3OH confirmed that cyclo(–δ-Ava–l-Pro–)2 has a C2 symmetric conformation consisting of all-trans peptide-bond backbones in all solvents, and that the change in polarity of the solvent induces a difference in the rotational states of the Pro αC–C=O single bond.
Glycosylation Using 2-Azido-3,4,6-tri-O-benzyl-2-deoxy-d-glucose, -galactose, and -mannose with the Aid of p-Nitrobenzenesulfonyl Chloride–Silver Trifluoromethanesulfonate–Triethylamine System
Authors: Koto Shinkiti , Asami Kazuyasu , Hirooka Motoko , Nagura Kazuo , Takizawa Mizue , Yamamoto Satoko , Okamoto Nami , Sato Mitsuko , Tajima Hiromi , Yoshida Toyosaku , Nonaka Nobuo , Sato Tadaaki , Zen Shonosuke , Yago Kazuo , Tomonaga Fumiya 
Published: December 2003

Abstract
This report describes a simple synthesis of 2-azido-3,4,6-tri-O-benzyl-2-deoxy-d-glucopyranose. Glycosylation using this as well as 2-azido-3,4,6-tri-O-benzyl-2-deoxy-d-galactopyranose and -mannopyranose was achieved with the aid of a reagent system consisting of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, and triethylamine, and its modifications. O-(2-Acetamido-2-deoxy-β-d-glucopyranosyl)-(1→4)-O-α-d-mannopyranosyl-(1→4)-α-d-mannopyranose, the repeating unit of the main chain of the O-specific cell wall polysaccharide of E. coli 058 was synthesized.
Oxidative Addition of Aryl and Benzyl Trifluoroacetates to Zerovalent Palladium Complexes with Two Modes of C–O Bond Cleavage Processes
Authors: Nagayama Kazuhiro , Shimizu Isao , Yamamoto Akio 
Published: December 2003

Abstract
The aryl trifluoroacetates oxidatively added to a zerovalent palladium complex 2a with acyl-O bond cleavage under mild conditions to give the corresponding trans-(aryloxo)(trifluoroacetyl)palladium complexes 3a—3c. But 4-nitrophenyl trifluoroacetate reacted with 2a to yield cis-[Pd(OC6H4-4-NO2)2(PMe3)2] 3d, which was produced with C–O bond activation followed by disproportionation reaction. In contrast, benzyl trifluoroacetates reacted with the Pd(0) complex with benzyl–O bond fission to form benzyl(trifluoroacetato)palladium complexes 4a—4d. Complexes 4a—4d are in equilibrium in solutions between trans and cis isomers, with the proportion of the cis isomer increasing in polar solvents. Palladium-catalyzed carbonylation of benzyl trifluoroacetate has been achieved in the presence of benzyl alcohol and triethylamine to yield benzyl phenylacetate.
A Facile Synthesis of Trifluoromethyl- and 3,3,3-Trifluoropropenyl-Substituted Aromatic Compounds by the Oxidative Desulfurization-Fluorination of the Corresponding Carbodithioates
Authors: Furuta Satoru , Kuroboshi Manabu , Hiyama Tamejiro 
Published: December 2003

Abstract
Trifluoromethyl-substituted aromatic compounds were easily synthesized by the oxidative desulfurization-fluorination reaction of readily accessible methyl arenecarbodithioates using [n-Bu4N]H2F3 and 1,3-dibromo-5,5-dimethylhydantoin (DBH) under extremely mild conditions. Use of N-bromosuccinimide or N-iodosuccinimide instead of DBH afforded difluoro(methylthio)methyl-substituted aromatics. In a similar way, 3,3,3-trifluoropropenyl-substituted aromatic compounds were readily prepared from the corresponding α,β-unsaturated carbodithioates.
Synthesis and Properties of Extremely Stable Tris(6-methoxy-1-azulenyl)methyl Cation and a Series of Di(1-azulenyl)phenylmethyl and (1-Azulenyl)diphenylmethyl Cations Stabilized by Methoxy Substituents
Authors: Ito Shunji , Kikuchi Shigeru , Morita Noboru , Asao Toyonobu 
Published: December 2003

Abstract
Extremely stable carbocations, tris(6-methoxy-1-azulenyl)methyl (8), bis(6-methoxy-1-azulenyl)(4-methoxyphenyl)methyl (9a), and (6-methoxy-1-azulenyl)bis(4-methoxyphenyl)methyl (10a) cations and a series of di(1-azulenyl)phenylmethyl and (1-azulenyl)diphenylmethyl cations having methoxy substituents on each phenyl group, i.e., di(1-azulenyl)(4-methoxyphenyl)methyl (9b) and (1-azulenyl)bis(4-methoxyphenyl)methyl (10b) cations and 3-methyl-1-azulenyl (9cand 10c) and 3,6-di-t-butyl-1-azulenyl (9d and 10d) analogues, were synthesized by hydride abstraction from the corresponding methane derivatives and their properties were fully characterized. The pKR+ values of 8 and 9a were well beyond 14.0. The value of 10a was determined as 13.2, which is higher by 10.2 pK units than that of (1-azulenyl)diphenylmethyl cation. The value also considerably increased by the methoxy substitution on each phenyl group. The values of 9b—d (pKR+ 11.7—13.4) and 10b—d (pKR+ 5.2—7.0) are higher by 1.0—1.4 and 2.2—2.4 pK units than those of the corresponding analogous benzyl and diphenylmethyl cations. The electrochemical reduction of 8, 9a—d, and 10a—d showed a wave at −0.88, −0.71 — −0.83, and −0.56 — −0.71 V (V vs. Ag/Ag+), respectively, upon cyclic voltammetry (CV). The relatively high reduction potentials also exhibited the stabilization of the methyl cations by the methoxy substituents. The oxidation of 8 in acetonitrile exhibited barely separated two-step, one-electron oxidation waves at a potential range of +0.90 — +0.98 V upon CV, although 9a—d and 10a—d did not show two similar waves at a narrow potential range. The wave is ascribed to the oxidation of two azulene rings to generate a trication species.
New Ionic Liquid Crystal Compounds Having a 1,3-Oxathiane or 1,3-Dioxane Ring
Authors: Haramoto Yuichiro , Akiyama Yoshiharu , Segawa Ryouichi , Nanasawa Masato , Ujiie Seiji , Holmes Andrew B 
Published: December 2003

Abstract
New pyridinium type thermotropic ionic liquid crystal materials bearing a 1,3-oxathiane ring in their central core: N-substituted 4-(5-alkyl-1,3-oxathian-2-yl)pyridinium bromides (8) and corresponding 1,3-dioxane analogs (10) were synthesized. And the mesomorphic behaviors of these two systems are compared. The principal feature of these compounds is to exhibit a smectic A phase over a very wide temperature range including room temperature [for example 8-4: G −7 SmA 166 I; 10-4: G −24 SmA 152 I (°C)].
Scheduling and Reliable Lead-Time Quotation for Orders with Availability Intervals and Lead-Time Sensitive Revenues
Authors: Keskinocak Pinar , Ravi R. , Tayur Sridhar 
Published: December 2003

Motivated by applications in the manufacturing and service industries, we consider two models for coordinating scheduling with lead-time quotation: a basic model with a single customer type, and an enhanced model where an additional second customer type expects immediate service or production. In both models, revenues obtained from the customers are sensitive to the lead time, there is a threshold of lead time above which the customer does not place an order, and the quoted lead times are 100% reliable. These models are related to well-known scheduling problems, which have been studied in both offline and online settings. We introduce the immediate quotation case and study it with the (traditional) online version. We provide complexity results for the offline case, and perform competitive analysis for the online cases. A natural question of bridging the gap between the online and quotation models leads us to the delayed quotation model, which we study briefly. The analysis of these models provides useful qualitative insights as well.
Learning and Forgetting: Modeling Optimal Product Sampling Over Time
Authors: Heiman Amir , McWilliams Bruce , Shen Zhihua , Zilberman David 
Published: December 2003

Firms use samples to increase the sales of almost all consumable goods, including food, health, and cleaning products. Despite its importance, sampling remains one of the most under-researched areas. There are no theoretical quantitative models of sampling behavior other than the pioneering work of Jain et al. (1995), who modeled sampling as an important factor in the diffusion of new products. In this paper we characterize sampling as having two effects. The first is the change in the probability of a consumer purchasing a product immediately after having sampled the product. The second is an increase in the consumer's cumulative goodwill formation, which results from sampling the product. This distinction differentiates our model from other models of goodwill, in which firm sales are only a function of the existing goodwill level. We determine the optimal dynamic sampling effort of a firm and examine the factors that affect the sampling decision. We find that although the sampling effort will decline over a product's life cycle, it may continue in mature products. Another finding is that when we have a positive change in the factors that increase sampling productivity, steady-state goodwill stock and sales will increase, but equilibrium sampling can either increase or decrease. The change in the sampling level is indeterminate because, while increased sampling productivity means that firms have incentives to increase sampling, the increase in the equilibrium goodwill level indirectly reduces the marginal productivity of sampling, thus reducing the incentives to sample. We discuss managerial implications, and how the model can be used to address various circumstances.
Ending Inventory Valuation in Multiperiod Production Scheduling
Authors: Fisher Marshall , Ramdas Kamalini , Zheng Yu-Sheng 
Published: December 2003

When making lot-sizing decisions, managers often use a model horizon T that is much smaller than any reasonable estimate of the firm's future horizon. This is done because forecast accuracy deteriorates rapidly for longer horizons, while computational burden increases. However, what is optimal over the short horizon may be suboptimal over the long run, resulting in errors known as end-effects. A common end-effect in lot-sizing models is to set end-of-horizon inventory to zero. This policy can result in excessive setup costs or stock-outs in the long run. We present a method to mitigate end-effects in lot sizing by including a valuation term V(IT) for end-of-horizon inventory IT, in the objective function of the short-horizon model. We develop this concept within the classical EOQ modeling framework, and then apply it to the dynamic lot-sizing problem (DLSP). If demand in each period of the DLSP equals the long-run average demand rate, then our procedure induces an optimal ordering policy over the short horizon that coincides with the long-run optimal ordering policy. We test our procedure empirically against the Wagner-Whitin algorithm and the Silver Meal heuristic, under several demand patterns, within a rolling horizon framework. With few exceptions, our approach significantly outperforms the other approaches tested, for modest to long model horizons. We discuss applicability to more general lot-sizing problems.
Modelling Practical Lot-Sizing Problems as Mixed-Integer Programs
Authors: Belvaux Gaetan , Wolsey Laurence A. 
Published: December 2003

In spite of the remarkable improvements in the quality of general purpose mixed-integer programming software, the effective solution of a variety of lot-sizing problems depends crucially on the development of tight formulations for the special problem features occurring in practice. After reviewing some of the basic preprocessing techniques for handling safety stocks and multilevel problems, we discuss a variety of aspects arising particularly in small and large bucket (time period) models such as start-ups, changeovers, minimum batch sizes, choice of one or two set-ups per period, etc. A set of applications is described that contains one or more of these special features, and some indicative computational results are presented. Finally, to show another technique that is useful, a slightly different (supply chain) application is presented, for which the a priori addition of some simple mixed-integer inequalities, based on aggregation, leads to important improvements in the results.
Problem–Solving Oscillations in Complex Engineering Projects
Authors: Mihm Jürgen , Loch Christoph , Huchzermeier Arnd 
Published: December 2003

Coordination among many interdependent actors in complex product development projects is recognized as a key activity in organizational theory. It is well known that this coordination becomes progressively more difficult with project size, but we do not yet sufficiently understand whether this effect can be controlled with frequent and rich communication among project members, or whether it is inevitable. Recent work in complexity theory suggests that a project might form a “rugged landscape,” for which performance deterioration with system size is inevitable.This paper builds a mathematical model of a complex design project that is divided into components (subproblems) and integrated back to the system. The model explicitly represents local component decisions, as well as component interactions in determining system performance. The model shows, first, how a rugged performance landscape arises even from simple components with simple performance functions, if the components are interdependent.Second, we characterize the dynamic behavior of the system analytically and with simulations. We show under which circumstances it exhibits performance oscillations or divergence to design solutions with low performance. Third, we derive classes of managerial actions available to improve performance dynamics, such as modularization, immediate communication, and exchanging preliminary information. Some of these have not yet received adequate attention in literature and practice.
Calibration with Many Checking Rules
Authors: Sandroni Alvaro , Smorodinsky Rann , Vohra Rakesh V. 
Published: December 2003

Each period an outcome (out of finitely many possibilities) is observed. For simplicity assume two possible outcomes, a and b. Each period, a forecaster announces the probability of a occurring next period based on the past. Consider an arbitrary subsequence of periods (e.g., odd periods, even periods, all periods in which b is observed, etc.). Given an integer n, divide any such subsequence into associated subsubsequences in which the forecast for a is between [i /n, i+1/n), i ∈ {0, 1, …, n}. We compare the forecasts and the outcomes (realized next period) separately in each of these subsubsequences. Given any countable partition of [0,1] and any countable collection of subsequences, we construct a forecasting scheme such that for all infinite strings of data, the long-run average forecast for a matches the long-run frequency of realized a's. A good Christian must beware of mathematicians and those soothsayers who make predictions by unholy methods, especially when their predictions come true, lest they ensnare the soul through association with demons. St. Augustine, De genesis ad litteram, Book II.
Sustaining Technology Leadership Can Require Both Cost Competence and Innovative Competence
Authors: Schmidt Glen M. , Porteus Evan L. 
Published: December 2003

Some firms, particularly in high-tech, appear to view technology leadership and cost leadership as separate and distinct ways of achieving high profits within a given product market. In contrast, we develop a model of technology competition suggesting that a firm's success in sustaining its technology leadership may hinge on its ability to produce the new product (resulting from the new technology) at lower cost, an ability we call the firm's “cost competence.” In our model, cost competence, above a critical hurdle level, is essential to the incumbent firm in its bid to retain technology leadership. The model also clarifies the role of “innovative competence,” which characterizes a firm's ability to turn an investment in new technology into a marketable product. We present an example of a standard product market model (for determining prices and production quantities for two competing products in the aftermath of the technology competition) in which the assumptions of our technology competition model hold.An additional key finding is that there can be discontinuities in the returns that accrue from enhanced cost competence. If a firm is on the right side of a “jump point,” its expected profits can be dramatically more than if it were only slightly less competent. These jump points arise where the firm's cost competence becomes sufficient to cause a competitor to decide against competing in the new technology, or to significantly drop its investment amount. When a potential competitor backs down, the prospect of high returns for the incumbent opens up.