Photoinduced radical polymerization of styrene derivatives via their cation radicals

Summary It was found that radical polymerization occurs when the mixture of p-methoxystyrene and styrene in the presence of electron acceptors is photoexcited in basic solvents. Concomitantly, p-methoxystyrenestyrene co-dimers: trans-1-(4-methoxyphenyl)-2-phenyl-cyclobutane and 1-(4-methoxyphenyl)-1,2,3,4-tetrahydronaphthalene are produced. From the results of some polymerization runs and the co-dimer structure, it is considered that the linear co-dimer cation radical is the common precursor for both radical polymerization and cationic dimerization, and the radical polymerization is initiated by its radical end.     

Growth and differentiation potentials in confluent state of culture of human skeletal muscle myoblasts

The transitional behaviors of myoblasts toward differentiation were investigated in the cultures at the low and high seeding densities (respectively, X₀ = 1.0 × 10³ and 2.0 × 10⁵ cells/cm²). In the culture at the low seeding density, an increase in confluence degree accompanied a decrease in growth potential (R_p), being R_p = 0.85 and 0.11 at t = 48 and 672 h, respectively. Myoblasts seeded at the high density resulted in the immediate cessation of growth with keeping the low range of R_p = 0.02–0.09 throughout the culture. The reduction of R_p led to the generation of three subpopulations of cells in proliferative, quiescent and differentiated states. Close cell contacts in the confluent state of high seeding culture induced cell quiescence to a higher extent with suppressing differentiation.     

Finite strip analysis of curved composite girders with incomplete interaction

This paper presents a finite strip analysis of curved composite girders with incomplete interaction. In the present analysis curved composite girder bridges are modelled by curved strip elements for the concrete slab and steel girder and spring elements for the shear connectors. The shear connectors are assumed as a two-dimensional spring element along the nodal line. The proposed method is applied to the analysis of curved box girders, curved plates and curved composite girder bridges with complete and incomplete interaction. Some analytical results obtained by this method are compared with the test results and theoretical values obtained by other methods, and they are in good agreement. Slip behavior of curved composite box girders is also discussed based on the results by the proposed method.     

Successful treatment of severe cytomegalovirus retinitis with foscarnet and intraocular injection of ganciclovir in a myelosuppressed unrelated bone marrow transplant patient

PURPOSE: To compare U.S. medical student Match results in 1996 for 19 categorical residency positions by specialty with those of the overall Match reported by the National Resident Matching Program (NRMP). METHOD: Data for the numbers of "active" senior U.S. student applicants (those who submitted rank lists), the numbers of U.S. seniors matched, and the numbers of unfilled positions for 19 specialties were obtained from a variety of sources. Chi-square analysis was performed to compare Match results for each independent specialty with the overall Match results. The level for statistical significant was set at p < .005. RESULTS: Eight specialties were identified as significantly more competitive than the overall Match process for both the percentage of U.S. seniors who successfully matched in that specialty and the ratio of unmatched U.S. senior applicants to unfilled categorical positions. Five specialties were identified as significantly less competitive for these two measures. Six specialties showed no significant difference in the percentages of U.S. students matching, but for three of these specialties there were more unmatched students than unfilled categorical positions. CONCLUSION: U.S. medical student Match results for categorical residency positions for different specialties vary significantly from the overall Match process. This information can be used in counseling senior medical students on their specialty selection and the residency application process.     

Feedback position control apparatus of tokamak plasma horizontal position with a digital drive

A plasma horizontal position feedback control system (PHPFCS) and a digital current drive (DCD) for controlling vertical magnetic field are made on an experimental base, and the horizontal position of a plasma in a small tokamak (HAMANA‐T) is controlled by PID operations from the initial phase of plasma generation. The DCD consists of constant‐current discharge units for multiple condensers and drives a digital current analogous as a whole to the control signal of PHPFCS in the range of ±90 A. The maximum value of the digital current increases in proportion to the number of units. This PHPFCS elongates plasma duration from 1.3 ms to 2.1 ms, smooths the waveform of plasma current, and reduces the plasma loop voltage from 25 V to 20 V. Furthermore, PHPFCS reduces the range of variation in plasma horizontal displacement from 3.5 cm to within 0.5 cm and makes it possible to set accurately the horizontal position from the initial phase in the inner region of a vacuum chamber. © 2000 Scripta Technica, Electr Eng Jpn, 130(4): 26–34, 2000     

Robust stabilization of a power system based on direct control of generator power by a series variable impedance unit

Power system stabilizing controllers have become more and more intelligent with the advancement of technologies in power electronics devices and circuit topologies. However, nonlinearities that are inherent in power system dynamics often spoil the robustness of a power system controller designed at an operating point. In this paper we propose a power system stabilizing controller using a variable series impedance unit with a control reference to obtain the prespecified linearized power swing characteristics. It is expected that the control scheme will be robust in the sense that the control parameters do not have to be readjusted even if the configuration or the operating point of the power system is changed. Some numerical studies demonstrate the significant effect of the proposed controller, in which a variable series impedance is used, on the power system stabilization. © 1998 Scripta Technica, Electr Eng Jpn, 123(4): 34–40, 1998     

Mechanical Strength and Electrical Conductivity of Cu–In Solid Solution Alloy Wires

Metallurgical and Materials Transactions A - Conductive spring wires for application in electrical components require high strength, high electrical conductivity, and convenient manufacturability....     

Preparation and Characterization of Superconducting B1-Type Mo1-xNbxN Thin Films

Solid-solution thin films, Mo_1−xNb_xN, with B1 (NaCl) structure have been deposited on substrates at 450°C by reactive sputtering of composite targets with Mo and Nb metals in an equimolar Ar and N₂ gas mixture. The lattice parameter of the solid solution increased linearly with an increase of Nb content, x . The superconducting transition temperature, T _c, of the Mo-rich films ( x ≦ 0.12) was around 6 K, which was lower than that expected from theoretical prediction. The residual resistivity ratio, r =ρ(300 K)/ρ(20 K), of the films varied with x , and a minimum value of r was observed in the vicinity of x = 0.5.