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1.
The study on the effect of NO on the growth of Chaetoceros curvisetus   总被引:1,自引:0,他引:1  
1 INTRODUCTION As a recently recognized information molecule in campaign of the “Molecule of the Year” by Sci- ence magazine, nitric oxide (NO) has attracted much attention from biologists and many other field scien- tists, for its very important physio…  相似文献   

2.
This study clarified the failure mechanism of a landslide on Ji'an-Dandong highway,through the detailed analysis of its geological condition.Then based on the back analysis of the broken landslide,take limit equilibrium method to evaluate the stability of the potential landslide.The result shows that the landslide is lack of safety stock,so anchor rope is designed to reinforce the landslide.  相似文献   

3.
The pressure grouting pile of driven tube can improve the load bearing capacity of the single pile from the mechanism of pressure grouting pile of driven tube.On the basis of analyzing the mechanism,the authors designed the machines and tools of pressure grouting,determined the operating manufacture and technology parameter on the pressure grouting secondly.The result shows that the pressure grouting pile of driven tube not only changes the pile type but also reduce the length of the pile and its engineering cost,it enhances the load bearing capacity of single pile an the same time.  相似文献   

4.
Systematic study on sorption behavior of o-nitrophenol on marine sediments was conducted.Isotherms of sorption of o-nitrophenol on marine sediments could be described by Freundlich model; and the isotherm of sorption of o-nitrophenol on HCl-treated sediment could be described by Langmuir model. The sorption behavior was affected by various factors including organic carbon content, aqueous solution salinity,temperature, and acidity. The sorption amount of o-nitrophenol increased when salinity and acidity of the aqueous solution increase, but decreased with increasing temperature. Organic carbon content in sediments had apparent effect on the behavior except for HCl-treated sediments.  相似文献   

5.
Analysis of cold tolerance on mangrove Kandelia candel leaf growing in different soil salinity along Jiulong River Estuary in South China showed that the cold tolerance decreased as the increase of soil salinity. The lethal temperatures of K. candel leaf were-10.4,-9.9 and-8.6℃ in Liaodong, Baijiao and Aotou, respectively. Under 1-2℃ cold stress treatment on detached leaves of K. candel, their caloric value gradually decreased, while electrolyte leakage gradually increased. The leaf's caloric value and electrolyte leakage in Aotou with higher soil salinity varied more largely than those in Liaodong with lower soil salinity. In K. candel leaf, total water content lowered a little, bound water content rose significantly and free water content dropped significantly with duration of cold stress. At the same time, reduction sugar, soluble sugar and starch content gradually decreased and sucrose content gradually increased. Bound water, free water and sucrose content in K. candel leaf from Aotou with higher soil salinity changed more slowly than those from Liaodong with lower soil salinity, but reduction sugar, soluble sugar and starch content in K. candel leaf from Aotou had faster variations than those from Liaodong. These data indicated that soil salinity can reduce cold tolerance of K.candel leaf by increasing negative effect of salt ions in cell membrane, inhibiting variations of water content, and aggravating consumption of material and energy.  相似文献   

6.
Reflecting the structure of igneous formation by calculating fractal dimension of logs, the fractal di- mension of pyroclastic is larger than lava. Structure of pyroclastic is more complicated than that of lava, so reflecting the structure of igneous formation's complexity with fractal dimension is feasible. It is feasible to reflect the structure of igneous formation's complexity with fractal dimension.  相似文献   

7.
The new polyenzyme method for making gravy from Harengula zunasi offal involves protein enzymolysis with flavorase after proper alkaline and neutral protease levels were established by orthogonal trials to select the best hydrolytic conditions for processing offal with alkaline and neutral protease. The conditions for the polyenzyme method were pH of 7.0, temperature of 50℃ , alkaline and neutral protease concentration of 1.5% respectively, hydrolysis time of 120 min, andflavorase concentration of 2.0% , for 60 min. The new gravy-making technology yields a nutritious and delicious gravy containing 40.3 % of total essential amino acids, with delicious amino acids Glu, Asp, Gly, Ala, Pro and Ser comprising 49.5% , total and amino nitrogen being respectively1.9 and 1.1 g/100 g (amino acid nitrogen being 61.0% of total nitrogen), The polyenzyme method was used to make 14.8% protein gravy from Harengula zunasi offal. In addition, in inorganic elements, the phosphorus content is the highest.  相似文献   

8.
The Humboldt squid Dosidicus gigas has a short life span,and environmental variability plays a significant role in regulating its population dynamics and distribution.An analysis of 1 096 samples of D.gigas collected by the Chinese commercial fishing vessels during 2013,2014,and 2016 off the Peruvian Exclusive Economic Zone,was conducted to evaluate the impacts of El Ni?o events on the somatic condition of D.gigas.This study indicates that the slopes of all beak variables in relation to mantle length(ML)for females were greater than those of males during 2013,2014,and 2016,and slopes of the upper crest length and the lower ro strum length significantly differed between females and males in 2013(P0.05).Variation in the slopes for beak variables among years was studied;no significant difference was observed(ANCOVA,P0.05).The Fulton's condition coefficients(K)of females and males in 2013 and 2014 were significantly greater than tho se in 2016(P0.01).01).The K values of females were greater than tho se of males in 201 3,2014,and 2016,and K values significantly differed between females and males in 201 3.In normal years,the chlorophyll a(Chl a)concentration showed an N-shaped variability from January to December.However,in the El Ni?o period,it tended to weaken the upwelling coupled with warm and low Chl a concentration waters.We suggest that the poor somatic condition of D.gigas during the El Ni?o year was resulted from the low Chl a concentration in the waters,and the abundance of D.gigas would decrease due to the unfavourable environment and the lack of prey items in the El Ni?o year.  相似文献   

9.
The fructification of the noeggerathialean foliage Plagiozamites is very likely a cylindric strobilus based on close associations from the Early Permian Lower Shihhotse Formation of Weibei Coalfield in Shaanxi and Dengfeng Coalfield in Henan. The strobilus is articulated. Sporophylls arise from the node, with the proximal parts slightly united and with a tight angle to the axis; distal parts upturned pointing upwards and nearly parallel to the axis, coveting the neighboring sporophylls of the next node. A sessile sporangium is situated at the adaxial side of each sporophyll. There are 12-16 sporangia and sporophylls in each node. This type of strobilus may have been identified as some sphenophyllalean/equisetalean cones in previous study.  相似文献   

10.
This study clarified the failure mechanism of a landslide on Ji' an-Dandong highway, through the detailed analysis of its geological condition. Then based on the back analysis of the broken landslide, take limit equilibrium method to evaluate the stability of the potential landslide. The result shows that the landslide is lack of safety stock, so anchor rope is designed to reinforce the landslide.  相似文献   

11.
Filling velocity and thickness of soft layer are major factors affecting subgrade stability according to an example study by means of finite element stress method (FESM). A case is studied and shows that the subgrade was slided because of excessive filling velocity. To determine a reasonable filling velocity is a key problem to a subgrade with marine soft soil.  相似文献   

12.
Effect of Uncertainty of Grid DEM on TOPMODEL: Evaluation and Analysis   总被引:3,自引:0,他引:3  
1 Introduction Digital Elevation Model (DEM) is a digital representa- tion of the earth’s surface and is typically represented in three formats: Grid DEM, TIN (Triangular Irregular Network) and contour-based storage structure. Being readily available and easily operating, Grid DEM has been widely applied to the analysis of hydrological problems (Moore et al., 1991) and other fields. Unfor- tunately, DEM has its inherent errors, the departure of a measurement from its true value, whic…  相似文献   

13.
The effects of degraded porphyran (P1) and natural porphyran (P) on the lifespan and vitality of Drosophila melanogaster are studied. The porphyrans, added daily to the food medium at 0.2% and 1% concentrations, can significantly increase the lifespan in average of 55.79 and 58.23 d in 0.2% P1 diet females and 1% P1 diet males, extending by 12.29% and 8.60% over the corresponding controls, respectively. The effects of porphyrans on D. melanogaster in heat-stress condition were also examined, and found a remarkable increase in survival time. The results which are consistently associated with the use of porphyrans are related to their free radical scavenger action. Considerable increase in vitality demonstrated that vitalities of middle-aged fly (assessed by measuring their mating capacity) was observed after porphyrans addition. Therefore, porphyrans are effective in reducing the rate of aging, and P1 in low molecular weight is better than natural P.  相似文献   

14.
As a very important component of a coastal system,tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are highly sensitive to the global change.The Quanzhou Bay,located along the middle part of Fujian coast of China,covers about 136.4km2,and the area of coastal wetland in the entire bay from intertidal to subtidal with 6m of water depth accounts for 96% of the total area.Seven short cores were collected and divided in situ with the interval of 5cm on the coastal wetlands of Quanzhou Bay on April 19,2006.The sediment samples were scattered and the grain sizes were measured by using Mastersizer 2000.Human beings' activities on tidal flat have disturbed the vertical distribution of sediments in stratigraphic sequence and accelerated the sedimentation rates.Grain size analysis results show that the grain size diameters increase and sediment becomes worse sorted towards the sea under the strong human disturbance;Spartina alterniflora can play a role of trapping the fine sediment;but near the bank,the sediment becomes coarse and there are two peak values on frequency curve influenced by the sandpile.The trough formed by human activities along the coastline changes the transport path of water and suspended sediment.The sediments are transported through the trough and deposit in it during the flood;the ebb flow is retarded by the flow output through the adjacent trough,and the deposited sediment can not be re-suspended;then,the sedimentation rate increases.In situ observation show that the sedimentation rate is about 8-10cm/yr.  相似文献   

15.
Ascertaining the relationship between "source-sink" landscape and non-point source(NPS) pollution is crucial for reducing NPS pollution, however, it is not easy to realize this target on cell unit scale. To reveal the relationships between "sourcesink" landscape and NPS pollution based on cell units of a small catchment in the Three Gorges Reservoir Region(TGRR), the runoff and nutrient yields were simulated first by rainfall events on a cell unit scale based on the Annualized AGricultural Non-Point Source Pollution Model(AnnAGNPS). Landscape structure and pattern were quantified with "sourcesink" landscape indicators based on cell units including landscape area indices and locationweighted landscape indices. The results showed that:the study case of small Wangjiagou catchment highlighted a good prediction capability of runoff and nutrient export by the AnnAGNPS model. Throughout the catchment, the spatial distribution trends of four location-weighted landscape indices were similar to the trends of simulated total nitrogen(TN) and total phosphorus(TP), which highlighted the importance of spatial arrangement of "source" and "sink" landscape types in a catchment when estimating pollutant loads. Results by Pearson correlation analysis indicated that the location-weighted landscape index provided a more comprehensive account of multiple factors, and can better reflect NPS-related nutrient loss than other landscape indices applied in single-factor analysis. This study provides new findings for applying the "source-sink" landscape indices based on cell units in small catchments to explain the effect of "source-sink" landscape on nutrient export based on cell unit, and helps improve the understanding of the correlation between "source-sink" landscape and NPS pollution.  相似文献   

16.
1GeologicalsettingThe researched area is located at the east margin of Eurasia plate and is 50 km from Changbaishan Vol-cano to west. The average elevation of the studied area is about 1 200 m and rivers flow mainly from the east to the west. There are To…  相似文献   

17.
Forecast of Flood in Chaohu Lake Basin of China Based on Grey-Markov Theory   总被引:1,自引:0,他引:1  
Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term forecast of natural precipitation at present. In the present paper the disadvantages of grey GM (1, 1) and Markov chain are ana- lyzed, and Grey-Markov forecast theory about flood is put forward and then the modifying model is developed by making prediction of Chaohu Lake basin. Hydrological law was conducted based on the theoretical forecasts by grey system GM (1, 1) forecast model with improved Markov chain. The above method contained Stat-analysis, embodying scientific approach, precise forecast and its reliable results.  相似文献   

18.
The effect of temperature on the life history characteristics of amictic females ( AF), unfertilized mictic females (UMF) and fertilized mictic females (FMF) in Brachionus calyciflorus was studied with replicated individual cultures at 20℃ ,25℃ and 30℃ , and with algae Scenedesmus obliquus for their food. There were highly significant effects of both temperature and female type, independently and interactively, on the duration of juvenile and post-reproduction periods, and the number of eggs produced by the rotifer per life cvcle. Among all the temperature-female type combinations, all the juvenile periods of FMF, and the post-reproduction periods of UMF and FMF at 20℃, were the longest, and the number of eggs produced by an UMF at 30℃ was the highest. There were highly significant effects of both temperature and female type on the duration of the reproduction period, but no clear correlation was observed between temperature and female type. The reproduction period of AF was longer than that of UMF and FMF.Only temperature influenced significantly the mean life-span of the three types of females. The duration of juvenile,reproduction and post-reproduction periods as well as the life-span of the three types of females were all reduced very significantly with rise of temperature, but the rates of reduction varied with female type. Among the three types of females, the number of eggs produced per life cycle by an UMF was the highest, and that of a FMF was the lowest. A significant relationship between the number of eggs produced per life cycle and temperature was observed only in the UMF.  相似文献   

19.
This research presents experimental data on mechanical foam bursting device,based on the high speed of air fluid impinging insidethe foam bursting device,foam bubbles disrupted as a consequence of pressures changed very quickly as shear force and their impact forces.Experimental data on foam-bursting capacity have been presented.Designed device can provide effective foam bursting on collapse foam.  相似文献   

20.
The Effect of Tide on the Global Climate Change   总被引:1,自引:0,他引:1  
The differential rotation between the solid and fluid spheres caused by tidal force could explain the 1500 to 1800 - year cycle of the worlds temperature. Strong tide increases the vertical and horizontal mixing of water in the oceans,dra-wing the cold Pacific water from the depths to the surface and the warm water from the west to the east, where it cools or warms the atmosphere above, absorbs or releases CO2 to decrease or increase greenhouse effect and to make La Nina or El Nino occur in the global. The moons declination and obliquity of the ecliptic affect the tidal intensity. The exchange of tidal energy and tide -generating force caused by the sun, moon and major planets makes the earths layers rotate in different speeds. The differenti-al rotation between solid and fluid of the earth is the basic reason for El Nino and global climate change.  相似文献   

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