The resin impregnant styrene/acrylic emulsion used for automobile filter paper was synthesized by semi-continuous emulsion polymerization using styrene and acrylate as main monomers.The effects of pH regulators on emulsion properties were studied by changing the kinds,concentration and control mode of the regulators.The results showed that,the pH value in emulsion polymerization was adjusted by the pH regulators,such as sodium bicarbonate,ammonia water and sodium hydroxide,and the water-resistance and bursting strength of the filter paper were markedly improved when the filter paper was impregnated with the emulsion.The comprehensive properties of the emulsion were the best and most stable when ammonia water with concentration of 5.0% was used as pH regulator to adjust the pH value in polymerization to 8.0 then adjust the pH value of the system after polymerization to 7.0～7.5.
Our analysis of the surface aerosol and ultraviolet(UV) measurements in Pearl River Delta(PRD) region shows that the sur-face UV radiation is reduced by more than 50% due to high aerosol concentrations.This has important impacts on urban eco-system and photochemistry,especially on ozone photochemical production over the region.The quantitative effect of aerosols on surface ozone is evaluated by analyzing surface observations(including ozone,ultraviolet radiation,aerosol radiative pa-rameters) and by using radiative and chemical models.A case study shows that the aerosol concentrations and UV radiation are significantly correlated with ozone concentrations.The correlation coefficient between the aerosol optical depth(AOD) and the PM10 mass concentration is very high,with a maximum of 0.98,and the AOD and UV radiation/ozone is anti-correlated,with a correlation coefficient of -0.90.The analysis suggests that ozone productivity is significantly decreased due to the reduction of UV radiation.The noon-time ozone maximum is considerably depressed when AOD is 0.6,and is further decreased when AOD is up to 1.2 due to the reduction of ozone photochemical productivity.Because the occurring probability of aerosol optical depth for AOD550 nm≥0.6 and AOD340 nm≥1.0 is 47,and 55% respectively during the dry season(October,November,December,January),this heavy aerosol condition explains the low ozone maximum that often occurs in the dry season over the Guangzhou region.The analysis also suggests that the value of single scattering albedo(SSA) is very sensitive to the aerosol radiative effect when the radiative and chemical models are applied,implying that the value of SSA needs to be carefully studied when the models are used in calculating ozone production.
Objective:To compare the effect of co induction with different triple anesthetics in blunting the cardiovascular responses to tracheal intubation.Methods:Sixty patients were randomly divided into three groups and induced with thiopental,proplfol or etornidate in combination with midazolam and fentanyl respectively.Blood pressure(BP) and heart rate(HR) were observed before and after fracheal intubation.Results:At tracheal intubation,HR in thiopental group was a little higher than the baseline( P 0.05),but in propofol and etomidate groups,the changes were not significant.BP in propofol group was markedly lower than the baseline( P 0.05),but in thiopental and etomidate groups,the changes were not significant.Before and after tracheal intubation,the occurrence of hypotension and bradycardia in propofol group was slightly higher than that in thlopental group,but there was no occurrence of hypotension in etomidate group.Conclusions:Coinduction with triple anesthetics proves to be effective in blunting the cardiovascular responses to tracheal intubation.Proplfol can completely eliminate the cardiovascular responses to tracheal intubation,but facilitate hypotension and bradycardia;thiopenlal and etomidate can only eliminate the increase of BP and HR respectively.
Using the non-hydrostatic meso-scale model MM5v3,dense fog that occurred from March 7 to March 8,2001 over the Nanling Mts.area was studied.With integrated field experiments observations,the occurrence,development and lift mechanism of fog were analyzed.The results indicate that before the coming of stratiform clouds,southerly warm and wet air ascended along mountainside and cooling condensation formed mountain fog.Then fog was formed by the stratiform on cloud-contacting mountaintop.Front inversion layer accelerated the development and longer duration of the lower cloud and fog.The intensity,occurrence time,mass content and the variation of temperature and relative humidity of the fog were in accordance with those of the observation.It showed that the meso-scale model has the potential to forecast mountain fog.
Traditional sports are human life and social development, the living condition culture has strong empirical, hardly, scarcity, therefore in the "cultural environment" the rise of this general developments in the field shall be included in the non-material cultural heritage has practical value. Based on the analysis of traditional ethnic sports non-material cultural heritage protection on the basis of the status quo, put forward the national tradition sports non-material cultural heritage protection path, to promote the national traditional sports and the benign development of the intangible cultural heritage.
Decomposition of sample by NaOH and H 2SO 4 treatment, Al +3 and EDTA form a complex, using xylene orange as a indicator, titration of excess amount EDTA by zinc standard solution, the content of aluminium can be calculated. Simple, quick and accurate determination of aluminium in the cryolite and aluminium fluoride was achieved by this method. The recoveries after addition of standard are 98～103%and 98～101%respectively. The relative standard deviation are 0.61% and 0.41%(n=11)respectively.
Objective:To study the incidences of the infants with lowered hair Zinc(Zn),copper(Cu),iron(Fe) and calcium(Ca),and the relationships with some diseases.Methods:The concentrations of hair Zn, Cu,Fe and Ca in 4776 infants were detected by atomic absorption spectrometer(AAS).Results:The incidence of the infants with lowered hair Zn, Cu, Fe and Ca was 17.71%, 9.95%,10.22% and 12.46% respectively. The incidence of recurrent respiratory tract infection(RRI),poor appetite and pica was 71.16%,57.57% and 11.47% respectively in the infants with lowered hair Zn;That of anemia was 15.79% and 73.16% respectively and that of RRI were 9.43% and 35.66% respectively in the infants with lowered hair Cu or Fe.That of rickets was 81.51% in the infants with lowered hair Ca.Conclusion:Lowered hair Zn,Cu,Fe,Ca are related with some diseases mentioned above in the infant.
