Statistics data shows that concentration ratio indexes, just as CR4, CR8 and CR100, of circulation industry in China is 0.57, 0.81 and 2.81.This means that concentration in circulation industry is on a rather low level.
In structure, the concentration ratio, economy of scale, differentiation of product and barrier to entry and exit are discussed, which comes to a conclusion that the Chinese construction enterprises are being in excess-competition.
At the concentration ratio of 1∶1,the LC50 of PCE and Cd in 24,48,72 and 96 h was 17.00,11.81,10.61 and 9.19 mg·L-1,and 17.00,11.81,10.61 and 9.19 mg·L-1,and the AI was 0.39,0.70,0.51 and 0.54,respectively,and the joint toxicity was also synergistic.
The experiments showed that the optimum conditions are:the reaction temperature 105 ℃,the concentration of 2-methylpyridine 0.075 mol/L,the concentration ratio of K2Cr2O7 to 2-methylpyridine 2∶1,the concentration of sulfuric acid was 9 mol/L,the reaction time was 2 h. The highest yield was 87.7%,the conversion was 97.6%,and the selectivity was 89.8%.
In this paper the Cd(Ⅱ) -glycinamide complex system was studied by differential pulse polarography ( DPP) at cadmium total concentration 1. 00 × 10-4 - 5. 00 ×10 -4mol·dm -3, fixed total-ligand to total-metal concentration ratio 50 - 200 and varied pH.
(5) In the north region of JiangHuai valleys, the rainstorm, rainstorm days, and the rainstorm concentration ratio in MeiYu period mainly show periodic variations ofquasi-five years and 2-3 years, the rainstorm intensity shows periodic variation of quasi-seven years, the rainstorm contribution ratio shows periodic variation of 6 years and 3 years.
METHODS:To calculate HHI and Concentration Ratio of pharmaceutical industry in 1990～1996.RESULTS & CONCLUSION:Nowadays market concentration of pharmaceutical industry is low,but the tendency of concentration is distinct.
The study results show that when the vacuum of the condenser and other heat exchange conditions are kept unchanged,an increase in heat exchange coefficient at the steam side of condenser heat exchange tubes can raise the critical fouling heat-resistance,thereby enhancing the concentration ratio of the circulating water and attaining the aim of saving water for the circulation water system along with the securing of sizable water-saving and environmental protection benefits.
In this paper the relation between circulating cooling water by high concentration ratio and water saving is introduced,the possibility of the improvement for high concentration ratio is discussed,the current approaches and the factors restricting high concentration ratio are also described.
The nonselective, selective and double-selective spin-lattice relaxation rates of some protons in huperzine E were acquired in the absence and presence of AchE at a concentration ratio of [ligand]/[protein] = 1: 0.005.
When the initial concentration of indole was 150 mg/L, the concentration ratio of indole to pyridine was in the range of 1-10.
It is found that the character of aggregates and the degree of their influence depend on the PM-to-PEI concentration ratio, polymer structure, and reaction temperature.
It is shown that the vapor composition depends on the concentration ratio of sodium and boron oxides in the condensed phase.
It is shown that the basicity of melts increases with an increase in the Na2O content at a constant concentration ratio of glass-forming oxides.