Influence of long-range interactions on superconductivity and phase separation

The t-J model is studied including a long-range 1/r repulsive interaction. It is observed that charge-density-wave states become stable as the strength of the 1/r term, V_coul, is increased. Due to this effect, the domain of stability of the superconducting phase that appears near phase separation at V_coul=0 is not enlarged by a 1/r interaction as naively expected. Nevertheless, superconductivity exists in a finite region of parameter space, even if phase separation is suppressed.     

The Matroid of Supports of A Linear Code

 A relation between the Hamming weight enumerator of a linear code and the Tutte polynomial of the corresponding matroid has been known since long ago. It provides a simple proof of the MacWilliams equation (see D. Welsh, Matroid Theory (1976)). In this paper we prove analogous results for the support weight distributions of a code. Received March 5, 1996; revised version October 28, 1996     

Characteristics of mince from pond-bred silvercarp (Hypophthalmichthys molitrix) and preliminary experiments on its use in sausages

The quality of fresh, chilled and frozen mince made from the flesh of pond-bred silvercarp (Hypophthalmichthys molitrix (Val)) was evaluated. Flavour panel scores for all minces were acceptable and this quality did not deteriorate during storage for one week in a domestic refrigerator (5–6°C) or for one year at ?20°C. The levels of oxidative rancidity (2-thiobarbituric acid analysis) in the minces were consistent with this maintenance of quality. Aerobic plate counts at 25°C of fresh mince rose from 7–9 × 10⁴ to 1.1 × 10⁵ after 6 days' storage at 5–6°C. Coliform and psychrotroph counts rose from 1.0 × 10¹ and 7–8 × 10³ to 5–4 × 10² and 1.3 × 10⁴, respectively. The functional and textural properties of pond-bred silvercarp mince in terms of salt-soluble protein content, water binding capacity and penetrometer values were measured on fresh, refrigerated and frozen samples. All-fish sausages and frankfurters developed from pond-bred silvercarp mince were assessed in laboratory and consumer tests against commercial beef sausages and frankfurters. The fish products competed well and achieved levels of acceptance similar to those of the beef-containing products. Texture measurements revealed slight changes in the fish products during storage for 7 days at 5–6°C. No spoilage was detected in any of the products after a week at 5–6°C. The nutritional advantages of the fish sausages and frankfurters are discussed.     

The fit between technology and structure as a predictor of performance in nursing subunits.

Regression analyses of field study data from 27 nursing subunits supported the hypothesis that a simple measure of fit between technology and structure is better predictor of quality of care than either technology or structure alone, or the two together. The results of this study were thus consistent with the growing body of congruency literature, and they suggest that a simple measure of structure may be quite useful in such research.     

Effects of the 65 mph speed limit on injury morbidity and mortality

Effective December 1987 and January 1988, the maximum speed limit on rural limited access highways in Michigan was raised from 55 mph to 65 mph. This study examined the effects of the raised limit on injury morbidity and mortality. A multiple time-series design was used, comparing roads where the speed limit was raised with roads where the limit remained unchanged. Data were collected on numbers and rates of automobile crashes, injuries, and deaths from January 1978 through December 1988. Time-series intervention analyses were conducted to estimate effects associated with the speed limit change while controlling for long-term trends, seasonal cycles, and other patterns. Statistical controls were also included for major factors known to influence crash and injury rates. Results revealed significant increases in casualties on roads where the speed limit was raised, including a 19.2% increase in fatalities, a 39.8% increase in serious injuries, and a 25.4% increase in moderate injuries. Fatalities also increased on 55 mph limited access freeways, suggesting that the 65 mph limit may have spillover effects on segments of freeways where the limit was not changed. No significant changes in fatalities or injuries were found on other types of roads. The increased convenience of reduced travel time with the higher speed limit is obtained at a significant cost in terms of injury morbidity and mortality.     

Strategy, structure, and performance issues of precompetitive R&D consortia: insights and lessons learned from SEMATECH

This paper examines the evolution of the role, structure, and orientation of SEMATECH in supporting the competitiveness of U.S. semiconductor industry between the late 1980s and the late 1990s. SEMATECH overcame its early challenges and succeeded by shifting its emphasis from horizontal (competitive) to vertical (precompetitive) collaboration, and then to a combined horizontal/vertical form (competitive). This evolutionary path in structure and strategy has broad implications for future relations between SEMATECH and the semiconductor industry as a whole, as well as industry R&D consortia in general. These implications are explored by detailing recent strategic developments at SEMATECH and their relationship to the market environment and structure in the global semiconductor manufacturing industry. This analysis is then extended to explore the implications for strategic research partnerships in other industries, which share particular salient characteristics with the semiconductor industry.     

Synthesis and characterization of novel hydrophobically modified polybetaines as pour point depressants

A novel hydrophobic monomer was synthesized from the acetoacetic ester and dodecylamine by condensation reaction in mild conditions. The modification by the dodecyl groups monomer was involved in the Michael addition reaction with acrylic (or methacrylic) acid followed by radical polymerization. Both linear and crosslinked novel betaine‐type polyampholytes bearing hydrophobic “tail” and hydrophilic “head” were obtained. The linear polymer was characterized by viscometry, FTIR, and Raman spectroscopy. Swelling–shrinking behavior of linear and crosslinked samples was studied in water–DMF and water–DMSO mixtures. The applicability of hydrophobically modified polybetaines as pour point depressants (fluidity improvers) was also demonstrated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1042–1048, 2004     

Influence of turbulent mixing on fast polymerization reactions

Investigations on development of a macrokinetics approach were generalized to the analysis of fast chemical reactions, mainly using cationic polymerization of isobutylene as an example, which is a new class of liquid‐phase processes. The removal of diffusional constraints on polymer synthesis, by intensification of turbulent mixing in the reaction zone, makes it possible to calculate the kinetic parameters of polymerization and polymer‐analogous reactions, to optimize the molecular characteristics of polymeric products obtained, and to control the character of the process as a whole. The laws pertaining to the progression of fast processes are considered for the synthesis of separate polymers, in particular stereoregular polydienes, ethylene–propylene copolymers, and chlorobutyl rubber. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 613–624, 2004