Ga 0.5 In 0.5 P layers have been grown by organometallic vapor-phase epitaxy using various values of input V/III ratio for two phosphorus precursors, phosphine, the conventional precursor, and tertiarybutylphosphine ͑TBP͒, a newly developed, less-hazardous precursor. For growth on nominally ͑001͒ GaAs substrates misoriented by 3°͑and in some cases by 0°or 6°͒ to produce ͓110͔ steps on the surface at a growth temperature of 620°C, the Cu-Pt-type ordering is found to be strongly affected by the input flow rate of the phosphorus precursor ͑V/III ratio͒. For decreasing input partial pressures below 3 Torr for PH 3 and 0.75 Torr for TBP the low-temperature photoluminescence ͑PL͒ peak energy increases indicating a lower degree of order. This is confirmed by transmission electron diffraction results. The decrease in the degree of order corresponds to a decrease in the concentration of ͓110͔-oriented P dimers on the surface, as indicated by surface photoabsorption spectroscopy results. These data indicate that the reduction in ordering is caused by the loss of the ͑2ϫ4͒ reconstructed surface during growth. The difference in the behavior for PH 3 and TBP is interpreted as due to the lower pyrolysis efficiency of PH 3 . The surface structure measured using high-resolution atomic force microscopy indicates that the ͓110͔ steps produced by the intentional misorientation of the substrate are bunched to produce supersteps approximately 30-40 Å in height for the lowest V/III ratios. The step height decreases markedly as the input phosphorus partial pressure increases from 0.4 to 0.75 Torr for TBP and from 1 to 3 Torr for PH 3 . This corresponds to a change from mainly monolayer to predominantly bilayer steps in the vicinal regions between bunched supersteps. Stabilization of the bilayer steps is interpreted as due to formation of the ͑2ϫ2͒ reconstruction on the ͑111͒B step edges. The degree of order is an inverted U-shaped function of the flow rate of the phosphorus precursor. Thus, use of very high input V/III ratios is also found to reduce the degree of order in the Ga 0.5 In 0.5 P layers. These high input phosphorus flow rates are found to result in a monotonic increase in the density of ͓110͔-oriented P dimers on the surface. This decrease in order is believed to be related to a change in the structure of kinks on the ͓110͔ steps at high V/III ratios.

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CuPt ordering is widely observed in GaInP epitaxial layers grown by organometallic vapor phase epitaxy. The formation of this spontaneously ordered structure during epitaxial growth is intimately related to the atomic-scale physical processes occurring on the surface, specifically surface reconstruction and the attachment of atoms at steps. For growth on singular ͑001͒ GaAs substrates the surface structure, measured using atomic force microscopy, is seen to consist of small islands surrounded by either monolayer or bilayer steps. An increase in the growth rate from 0.25 to 2.0 m/h with a constant tertiarybutylphosphine partial pressure at 670°C has no effect on either the degree of order or the step structure. Only the step spacing is observed to change. It decreases systematically as the growth rate is increased, following an approximate 1/͑growth rate͒ 1/2 dependence. As the growth rate increases, the time atoms have to rearrange before being frozen due to coverage by the next layer decreases. This leads directly to the dependence observed. These observations are consistent with previous observations which appear to show a close correlation between step structure ͑monolayer versus bilayer͒ and ordering, although the causative factor has not been determined.

Transmission electron microscope ͑TEM͒ and transmission electron diffraction ͑TED͒ studies have been performed to investigate the effects of V/III ratio on ordering and antiphase boundaries ͑APBs͒ in organometallic vapor phase epitaxial Ga 0.5 In 0.5 P layers grown onto ͑001͒ GaAs vicinal substrates at 670°C. TED and TEM examination showed that the degree of order is higher in the layer grown using a V/III ratio of 160 than in the layer grown using a V/III ratio of 40. TEM results showed that the higher V/III ratio could be used to suppress APBs. In addition, the growth of order-induced heterostructures, where the V/III ratio is increased abruptly during growth, could be used to block the propagation of APBs. Mechanisms are proposed to explain these phenomena.

The effect of electric field applied and Mg2+ doped on formation of calcium carbonatescale in circulating cooling water is investigated by using home-made experimental device, which can simulate the scaleof formationin local power plant. The results showthat high-voltage electrostatic fields and magnesium ions can inhibit scale growthin circulating cooling water. When the magnesium ion concentration is 4 mmol/L, the scale inhibition effect is the best under the action of the electric field (6 kV), and its scale inhibition rate can reach 44.56%. Meanwhile, some phenomenonare explained and confirmed by the results of first-principles calculations. The calculated shear modulus of aragonite is greater than that of calcite. This might be used to explain that aragonite is easier to adhere to the heat exchange surface. This is in good agreement with experimental results. Calcite has better anti-scaling property than aragonite. The crystal structure after physical water treatment is blunt, and the untreated crystal structure is sharp.