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We present an overview of the quantum design, growth and lasing operation of both IR and mid-IR OPSL structures aimed at extracting multi-Watt powers CW and multi-kW peak power pulsed. Issues related to power scaling are identified and discussed. The IR OPSLs based on InGaAs QW bottom emitters targeted at wavelengths between 1015nm and 1040nm are operated in CW mode (yielding a maximum power of 64W) and pulsed (peak power of 245W). The mid-IR top emitter OPSLs designed to lase at 2m are based on a novel lattice mismatched growth using InGaSb QWs and yield a maximum peak power of 350W pulsed.

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We present a study of the use of amine-functionalized, mesoporous silicas as supports for nanoparticulate palladium, and the use of the composite materials as heterogeneous catalysts for the Suzuki coupling of aryl bromides. Upon modification of the silica, via attachment of N-functionalized aminopropylsilyl ethers to surface silanol groups, only a small reduction in surface area and average pore diameter is observed. The mesoporosity and high surface area are also maintained after introduction of nanoparticulate palladium, as evidenced by the measurement of BET nitrogen sorption isotherms. Electron microscopy shows that the palladium particles are well-dispersed and of typical diameter 3−6 nm. Catalysis was initially tested using the coupling of phenylboronic acid with 4-bromoanisole in the presence of K2CO3 and with toluene as solvent. This revealed that the choice of organic modification has a crucial role in determining the activity and recyclability of the catalyst:  optimum behavior was found for diamine- and triamine-containing systems, while quaternary alkylammonium salts showed poor activities. The optimized catalysts are also active in the coupling of a range of aryl bromides and phenylboronic acids, and after three catalytic runs they show virtually no drop in activity. Upon further cycling, however, and after six catalytic runs, we do observe a drop in activity, and this is accompanied by some leaching of palladium and pore-blocking by reaction products and byproducts.

A range of ortho-metalated catalysts with alkylphosphine ligands of the general formula [Pd(X)(κ²N,C-C6H4CH2NMe2)(PR3)] have been synthesized, and the crystal structures of five examples (R = Cy, X = TFA, OTf, Cl, I; PR3 = PCy2(o-biphenyl), X = TFA) have been determined. The crystal structures of two dimeric precursor complexes, [{Pd(μ-TFA)(κ²N,C-C6H4CH2NMe2)}2] and [{Pd(TFA)(κ²N,C-C6H4CH&dbd;NⁱPr)}2], have also been determined. The application of the phosphine adducts to both Suzuki coupling and Buchwald−Hartwig amination reactions with aryl chloride substrates was examined, and the performance of these catalysts versus conventional palladium sources was evaluated. In general the palladacyclic complexes show considerably enhanced activity. Typically, the best activity is seen with tricyclohexylphosphine adducts in Suzuki coupling and tri-tert-butylphosphine analogues in amination reactions. In nearly all the amination reactions performed, small amounts of a second product species were observed, namely 4,6-bis(aryl)-3,4-dihydro-2H-[1,4]oxazines. The crystal structure of one example, 4,6-bis(4-methoxyphenyl)-3,4-dihydro-2H-[1,4]oxazine, was determined. Studies on the activation of palladacyclic precatalysts in the coupling of morpholine led to the isolation of a morpholine adduct, [Pd(TFA)(κ²N,C-C6H5CH2NMe2){NH(CH2CH2)O}], which was structurally characterized by X-ray analysis.

The orthometalated complex [{Pd(μ-Cl){κ²-P,C-P(OC6H2-2,4-^tBu2)(OC6H3-2,4-^tBu2)2}}2] reacts with phenylboronic acid hydrate and K2CO3 in dimethylacetamide to give [Pd{κ²-P,C-μ²-O-P(O)(C6H2-2,4-^tBu2)(C6H3-2,4-^tBu2)(DMAc)}]. When the reaction is repeated in dimethylformamide 3,3‘,5,5‘-tetra-tert-butyl-2,2‘-biphenol is isolated. Both compounds have been characterized crystallographically. The reaction of palladium dichloride with PⁱPr2(OC6H4-4-Et) in 2-methoxyethanol followed by recrystallization in the presence of ethanol leads to the formation of trans-[PdCl2{PⁱPr2(OEt)}2], which was also characterized by crystallography. To determine whether related solvolytic processes have a bearing on catalytic activity, the performance of a range of catalysts with “hydrolyzed” and “nonhydrolyzed” ligands was assessed in the Suzuki coupling of aryl bromides. In some cases it was evident that hydrolysis plays a significant role on the catalytic activity; however, this depends not only on the ligand, but also on the combination of ligand and palladium precursor.

Abstract: May 1987 is a month that will not be forgotten in the South Pacific. The first of two military coups d'etat led by Colonel Sitiveni Rabuka not only transformed the course of post-colonial political development in Fiji, but this event also had profound implications for international relations in the region. Co-incidentally, May 1987 was also the month when detailed results of Fiji's second national population census since Independence in 1970 became available. The 1986 census documents Fiji's population on the eve of a political revolution which has the potential to cause significant economic and social change. The demographic process most likely to be affected in the short-term by the coups is population movement, both within Fiji and to overseas destinations. This: paper examines developments in population movement between 1970 and 1986 with particular reference to an acceleration in levels of migration overseas by Indians and an exodus of Fijians from rural village communities for towns on Viti Levu and Vanua Levu. Trends in internal and international migration are evaluated at a range of spatial scales — national, regional and local. Some speculation on the effect of political and economic changes since May 1987 on these population movements attempts to provide a contemporary perspective on demographic developments over the last 15 years.

Regenerative braking is of considerable importance in increasing the efficiency of the system using dc traction vehicles or with dc motors requiring frequent starting and braking. Generally phase control is used for feeding back the regenerative power into the ac lines. This method results in poor power factor and low value of regenerative power. In order to improve the power factor, a method based on forced commutation is proposed in this paper, which, in addition realises large regenerative power. Power control circuits are discussed. Experimental verification of the basic principles involved is carried out

Local hemispherical effective emissivities and integrated cavity emissivities are computed for isothermal and nonisothermal diffuse double cones (a conical section joined to a conical frustum) with and without lids, and are compared with corresponding values for cylindrocones. The local emissivities increase and become more uniform with increasing taper of the frustum. They are also considerably higher when there is a lid. For cavities with the same conical section, length, and aperture, a lidded double cone is blacker than a lidded cylindrocone when the front half of the frustum is invisible, but less black otherwise. For double cones of the same length, diameter, and aperture, the best choice of cone and frustum angles depends upon the particular viewing conditions. The integrated cavity emissivities vary only slightly with the angles of cone and frustum when the frustum is relatively long, and the normal emissivity (for a small on-axis detector a large distance away) is higher than the hemispherical emissivity (for a detector that fills the cavity aperture). When the frustum is relatively short, all of these vary substantially with angle, and the hemispherical emissivity can be higher than the normal emissivity. There is a marked variation of both local and integrated emissivities with wavelength in nonisothermal double cones; e.g., for the particular cases illustrated, the normal spectral emissivities change by from 4% to 6% and the hemispherical spectral emissivities by from 17% to 20% between 0.3 and 1 μm for a 1% temperature variation at 1300 K. The amount of the change in these spectral emissivities also depends upon the geometry of the cavity.

Local, hemispherical, effective emissivities and integrated cavity emissivities have been computed for isothermal and nonisothermal diffuse conical and cylindrical cavities having lids with circular apertures. The local emissivities of the walls increase rapidly with decreasing aperture diameter and are moderately insensitive to the value of the lid emissivity. The integrated emissivity increases or decreases with the distance of the detector from the cavity; the direction of the change depends upon the cavity geometry. For a nonisothermal cavity, the effective spectral emissivity changes substantially with both wavelength and cavity temperature; consequently, it is in general significantly different from the effective total emissivity.

Local, hemispherical, effective emissivities and integrated cavity emissivities are computed for isothermal and nonisothermal diffuse cylindro-cones (a cylindrical section of radius R_2 and length L_2 joined to a conical base of length L_1 and half-angle θ), with and without lids, and are compared with corresponding values for the limiting cases of right circular cones and cylinders. The local emissivities everywhere along the walls are considerably higher in a cylindro-cone with a lid than in a similar one without, and also increase rapidly with decreasing cone angle. They are considerably higher in a cylindro-cone than in a cone of length L_1 or in a cylinder of length L_2. On the other hand, for cavities of the same total length, the cylinder has the highest local emissivities except at and near the base, where the emissivity of the cone is highest. There is a regular transition between these two extremes through various intermediary cylindro-cones. The normal integrated cavity emissivities are higher than the hemispherical emissivities for cavities for which (L_1 + L_2)/2R_2 ≳ 0.8. The local and integrated spectral emissivities of nonisothermal cylindro-cones change markedly with wavelength and somewhat with cavity reference temperature. Approximate local emissivities for nonisothermal cylindro-cones can be obtained from corresponding isothermal ones in a simple manner, with useful accuracy.

The reaction of [RuHCl(CO)(PPh3)3] (1a) with P&tbd1;CCMe3 results in the formation of the phosphaalkenyl complex [Ru(P&dbd;CHCMe3)Cl(CO)(PPh3)2] (2a). Being coordinatively unsaturated, 2a reacts reversibly with CO to provide [Ru(P&dbd;CHCMe3)Cl(CO)2(PPh3)2] (3) and with isonitriles (CNR) to provide [Ru(P&dbd;CHCMe3)Cl(CNR)(CO)(PPh3)2] [R = CMe3 (4a), C6H3Me2-2,6 (4b)]. With an excess of CNCMe3, the salt [Ru(P&dbd;CHCMe3)(CNR)2(CO)(PPh3)2]Cl 5(Cl) is obtained. The anionic bidentate ligand K[H2B(bta)2] (bta = benzotriazolyl) reacts with 2a via chloride displacement to provide [Ru(P&dbd;CHCMe3){H2B(bta)2}(CO)(PPh3)2] (6) while the facially tridentate macrocycle 1,4,7-trithiacyclononane ([9]aneS3) provides [Ru(P&dbd;CHCMe3)(CO)(PPh3)([9]aneS3)]Cl 7(Cl). The thiocarbonyl complex [Ru{P&dbd;CHCMe3)Cl(CS)(PPh3)2] (2b), obtained from [RuHCl(CS)(PPh3)3] (1b) and P&tbd1;CCMe3, reacts with [Et2NH2][S2CNEt2] or [9]aneS3 to provide [Ru(P&dbd;CHCMe3)(S2CNEt2)(CS)(PPh3)2] (8) and [Ru(P&dbd;CHCMe3)(CS)(PPh3)([9]aneS3)]Cl 9(Cl), respectively. The salt 5(Cl) or the neutral complex 4a react slowly with air (accelerated by base), to provide the λ⁵-phosphaalkenylmetallacycle [Ru{P(&dbd;O)C(CMe3)C(&dbd;O)}(CNCMe3)2(PPh3)2] (10). The reactions of 1a with sodium formate or ferrocene carboxylate provides the complexes [Ru(P&dbd;CHCMe3)(O2CR)(CO)(PPh3)2] (R = H (11a), C5H4Fe(η-C5H5) (11b)). The X-ray crystal structure of 11a is reported.

The reaction of [IrCl(CO)(PPh3)2] with LiSeC&tbd1;CR (R = C6H4Me-4) provides [Ir(SeC&tbd1;CR)(CO)(PPh3)2] (1), which undergoes oxidative addition reactions with oxygen, methyl iodide, benzeneselenenyl chloride and bis(4-tolylethynyl)mercury to provide the complexes [Ir(SeC&tbd1;CR)(η²-O2)(CO)(PPh3)2] (2), [Ir(CH3)(SeC&tbd1;CR)I(CO)(PPh3)2] (3), [Ir(CH3)I2(CO)(PPh3)2] (4), [IrCl(SePh)(SeC&tbd1;CR)(CO)(PPh3)2] (5), and [Ir(C&tbd1;CR)(HgC&tbd1;CR)(SeC&tbd1;CR)(CO)(PPh3)2] (6). The complexes 1−3, and 5, and 6 each contain the alkyneselenolate ligand bound to iridium in a monodentate manner through selenium.

Di-orthometalated iridium complexes of triaryl phosphites have been prepared and characterized. The synthesis of the triphenyl phosphite derivative [IrH(cod){P(OC6H4)2(OC6H5)}], 3, requires a circuitous route by treatment of [IrCl(cod){P(OPh)3}] with methyllithium and then methanol. However, with the hindered phosphites P(OAr)3 (Ar = C6H4-2-^tBu or C6H3-2,4-^tBu2) the di-orthometalated species 5a,b are readily obtained by reaction of the phosphite with [{Ir(μ-OMe)(cod)}2] or [Ir(cod)(py)2][PF6]. The mechanisms of these reactions have been investigated and are different. Both 5a and 5b are catalysts for imine hydrogenation. The complexes [IrH5{P(OAr)3}2] have been isolated from hydrogenation reactions and synthesized independently.

Luminosity functions have been measured for four normal trichromats for three field sizes (1°, 12′, 1.5′) at various levels of retinal illuminance. As the illuminance decreases the reverse Purkinje effect is observed, i.e., there is a decrease in spectral sensitivity of the eye to blue relative to red. The dependence of the spectral sensitivity on field size is not pronounced for the experimental conditions used here. Considerable differences are found between the luminosity functions of the observers. These differences are several times larger than those obtained on repeated curves by any observer. It is shown that the use of an average luminosity function may give very misleading results in some cases.A comparison is made with the data obtained by previous workers.

Wavelength discrimination curves have been measured for two normal trichromats for three field sizes and various intensities. In order to obtain high-intensity levels in the blue region, a high-pressure xenon arc was used as a source. Results for the 1° field agree essentially with those of previous workers. The higher blue intensities have led to the establishment of a definite minimum at 420 mμ. Results for the smaller field sizes differ considerably from previous data. The chief reason for this seems to he in the viewing technique used. While previous authors employed strict fixation, this paper reports data obtained with a scanning technique. The effect of different methods of plotting is briefly discussed.

The high-frequency modulation characteristics of GaAs-based bipolar cascade vertical cavity surface-emitting lasers operating at 980 nm with GaAs tunnel junctions and p-doped Al_0.98Ga_0.02As oxide apertures have been measured. We achieve −3 dB laser output modulations of 6.5 GHz for two-stage and 9.4 GHz for three-stage devices in response to small-signal current injection at an operating temperature of −50°C.

Platinum complexes with π-acidic, ortho-metalated triaryl phosphite and phosphinite ligands show unexpectedly good activity in Suzuki biaryl coupling reactions with aryl bromide substrates.

A high-power surface emitting flared laser with curved feedback grating is reported. Low threshold, low divergence out-coupling is achieved. Single longitudinal mode operation with surface emitting power in excess of 110 mW and sidemode suppression of > 40 dB is demonstrated.

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It has been suggested that Humphrey's ADE system may be an improvement on the Bain system. To compare their efficiencies we have studied 20 anaesthetized adults who had controlled ventilation established with a circle absorber system at a VE sufficient to maintain normocapnia. Patients were then randomly allocated to either a Bain or an ADE system. Fresh gas flow was sufficient to keep PE CO2 constant for 30 min. The other circuit was then used for an additional 30 min. The required FGF was 54 ml kg−1 min−1 for the Bain system, compared with 67 ml kg−1 min−1 for the ADE system. We conclude that, during controlled ventilation, the ADE system is 25% less efficient than the Bain system.

The purpose of this study was to identify EEG changes associated with low-dose propofol infusion producing only sedative effects, and to describe the memory effects of low-dose propofol infusion. Ten healthy volunteers underwent EEG monitoring (at Fz, Cz, Pz and Oz electrode sites) before, during and after propofol 0.5mg kg−1 i.v. bolus and 75 fig kg−1 min−1 as an infusion. Mean serum concentration of propofol during infusion was 0.86 (SD 0.14) μg ml−1. The EEG changed significantly during infusion, with increased power in the beta, (15–20 Hz). beta2 (20.5–30 Hz) and delta (1–3.5 Hz) frequencies. Beta1 and beta2 power changes were most marked at the Fz and Cz electrodes. Subjects were sedated, but able to complete cognitive tasks. Visual analogue scales of attention and sleepiness were obtained throughout the study and demonstrated a sedative effect during propofol infusion, but were not a significant factor in memory performance or EEG changes. A verbal learning task (Rey Auditory-Verbal Learning Task) administered before, during and after infusion showed a marked reduction in short-term memory capacity and dramatically impaired free recall and recognition during infusion. Nine of 10 subjects had partial amnesia for complex visual scenes presented during infusion, recalling less than 50% of the material. Stronger cueing was required to retrieve information presented during propofol infusion, with an increase in mean retrieval time from 95.4 (41.2) s to 426.8 (83.1) s. EEG and memory effects resolved quickly after the end of infusion. We conclude that anterior, high frequency EEG activity increases significantly during low-dose propofol infusion and that propofol produces significant memory impairment which has characteristics of true amnesia, concurrent with changes in beta, power in the EEG. The fact that low-dose propofol produces significant changes in both cognitive and EEG measures warrants further investigation into the utility of the EEG power spectrum as a useful monitor of amnesia during conscious sedation with propofol.