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3,3′,5,5′-Tetra-tert-butyl-2′-sulfanyl[1,1′-biphenyl]-2-ol (H2[tBu4OS]) was prepared in 24 % yield overall from the analogous biphenol using standard techniques. Addition of H2[tBu4OS] to Mo(NAr)(CHCMe2Ph)(2,5-dimethylpyrrolide)2 led to formation of Mo(NAr)(CHCMe2Ph)[tBu4OS], which was trapped with PMe3 to give Mo(NAr)(CHCMe2Ph)[tBu4OS](PMe3) (1(PMe3)). An X-ray crystallographic study of 1(PMe3) revealed that two structurally distinct square pyramidal molecules are present in which the alkylidene ligand occupies the apical position in each. Both 1(PMe3)A and 1(PMe3)B are disordered. Mo(NAd)(CHCMe2Ph)(tBu4OS)(PMe3) (2(PMe3); Ad=1-adamantyl) and W(NAr)(CHCMe2Ph)(tBu4OS)(PMe3) (3(PMe3)) were prepared using analogous approaches. 1(PMe3) reacts with ethylene (1 atm) in benzene within 45 minutes to give an ethylene complex Mo(NAr)(tBu4OS)(C2H4) (4) that is isolable and relatively stable toward loss of ethylene below 60 °C. An X-ray study shows that the bond distances and angles for the ethylene ligand in 4 are like those found for bisalkoxide ethylene complexes of the same general type. Complex 1(PMe3) in the presence of one equivalent of B(C6F5)3 catalyzes the homocoupling of 1-decene, allyltrimethylsilane, and allylboronic acid pinacol ester at ambient temperature. 1(PMe3), 2(PMe3), and 3(PMe3) all catalyze the ROMP of rac-endo,exo-5,6-dicarbomethoxynorbornene (rac-DCMNBE) in the presence of B(C6F5)3, but the polyDCMNBE that is formed has a random structure.

Through relatively straightforward techniques that begin with Mo(NAr)(CH-t-Bu)[OCMe(CF3)2]2 (Ar = 2,6-i-Pr2C6H3), we have prepared Mo(NAr)(CMePh)(OMesityl)2, [Mo(NAr)(CMePh)(OC6F5)2]2, Mo(NAr)(CMePh)(OC6F5)2(MeCN), Mo(NAr)(CMePh)(OC6F5)2(bipyridyl), Mo(NAr)(CMePh)(Cl)2(bipyridyl), Mo(NAr)(CMePh)(Cl)(OHMT)(MeCN) (OHMT = O-2,6-(2,4,6-Me3C6H2)2C6H3), and Mo(NAr)(CMePh)(Pyrrolide)(OHMT). X-ray studies reveal that in five compounds the alkylidene isomer (A) is that in which the phenyl group in the alkylidene points toward the imido nitrogen. In Mo(NAr)(CMePh)(OC6F5)2(MeCN) the isomer in which the methyl group points toward the imido nitrogen (isomer B) has cocrystallized with isomer A (12%). In two 14e compounds that contain isomer A, the Mo═C-C angles differ by 30-36°, consistent with a Mo...C-Hβ agostic interaction. Several of the complexes reported here react readily with ethylene, 1-decene, or cyclooctene to give the expected products, thus confirming their viability as initiators or intermediates in metathesis reactions.

In this paper, an efficient rapid convergent control algorithm will be developed and will be compared with other adaptive control algorithms using a plate-cavity system. The plate-cavity system used for these numerical experiments is a test bed of noise suppression technology for expendable launch vehicles. It consists of a flexible plate backed by a rigid cavity. Piezoelectric (PZT) actuators are considered to be bonded on both sides of the plate symmetrically. The plate is bombarded with an amplified random noise signal, and the control system is used to suppress the noise inside the cavity generated by the outside sound source. Other control algorithms included for the comparisons are LMS Widrow's finite impulse response (FIR) adaptive control algorithm [1], and a modified Godard's algorithm [2]. Comparisons of the random noise attenuation capability, transient and convergence performance, and computational requirements of each algorithm will be made as the order of the controller and relevant convergence parameters are varied.

Labor recruitment in Taiwan has been determined by labor cost and the response of industry. Taiwanese industries solve the labor shortage by hiring part-time and overseas labor which yields short-term economic benefits, although it will take longer to attain full industrial maturity.

Taiwanese government has tried to enhance trade by increasing domestic demand and export markets, and altering mercantilist regulations of trade. The government's efforts to restructure the economy also include the liberalization of imports, and controls on foreign exchange and financial systems. The policies implementing the efforts have been formulated to establish Taiwanese markets in other international markets.

The complex permittivity and permeability of La0.7Sr0.3MnO3 (LSMO)-epoxy composite absorbers are investigated in the microwave ranges from 2 to 18 GHz by transmission/reflection method. A negative magnetic susceptibility of perovskite oxides has been obtained in the frequency range of 4-18 GHz. By the use of the cavity perturbation technique, the negative magnetic susceptibility for 7.5-14 GHz is reconfirmed. For LSMO-epoxy composite with 80 wt % fillers, the maximum reflection loss can reach 23 dB at 10.5 GHz and the absorbing bandwidth above 10 dB is 1.5 GHz with 2 mm thickness. [ABSTRACT FROM AUTHOR]

In this study, the influence of the addition of carbon nanotube (CNT) (0, 0.5, 1.0, and 2.0 wt %) on complex permittivity, complex permeability, and reflection loss for La0.7Sr0.3MnO3-δ (LSMO)/ polymer composites was investigated. Microwave absorbing composites were prepared by molding and curing a mixture of LSMO powders, CNTs, and epoxy resin. The complex permittivity and complex permeability for LSMO/CNT composites were examined by a cavity perturbation technique. The experimental results showed that the complex permittivity increased with increasing CNT addition and the imaginary part of the permeability decreased with rising frequency. In the present study, a microwave absorbing composite filled with 80 wt % LSOM powders and 2 wt % CNTs exhibited the optimum performance, that is, the microwave absorbing peak was -22.85 dB at 9.5 GHz and the -10 dB absorbing bandwidth reached 3.3 GHz for the sample with a matching thickness of 3 mm. [ABSTRACT FROM AUTHOR]

A cavity perturbation resonance technique is used to determine the complex permittivity and permeability of iron-based composite absorbers prepared by mixing various weight percentages of carbonyl iron powder with epoxy as the matrix. The complex permittivity ([variant_greek_epsilon]′-j[variant_greek_epsilon]″) and permeability (μ′-jμ″) are measured around X-band (7–12.5 GHz for permittivity and 7.5–14 GHz for permeability) by the cavity perturbation resonance technique and the results are compared with those obtained by the transmission/reflection method. Experimental results show that the average differences of real parts of permittivity ([variant_greek_epsilon]′) and real and imaginary parts of permeability (μ′ and μ″) measured by these two techniques are less than 10%. The differences in [variant_greek_epsilon]″, however, is apparently higher than the others. As a general trend, the difference increases with increasing weight percentage of carbonyl iron. [ABSTRACT FROM AUTHOR]

A study was conducted to identify the determinants of fast repeat migrations of the labor force of Taiwan. Analysis of the data from 1980-1989 national migration surveys of the labor force revealed that the nature and outcome of previous migrations affect the possibility to make fast repeat migration. It was also found that employees and the unemployed are more likely to do fast return migration than employers, the self-employed and unpaid family workers.