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1.
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   

2.
Gelatin from the sea cucumber (Paracaudina chinens var.) was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff (MWCO). The portion (less than 5 kDa) was further separated by Sephadex G-25. The active peak was collected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals (O2·^-) and hydroxyl radicals (·OH) of the fraction with the highest activity were 29.02% and 75.41%, respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria.  相似文献   

3.
The original purpose of Vessel Monitoring System(VMS) is for enforcement and control of vessel sailing. With the application of VMS in fishing vessels, more and more population dynamic studies have used VMS data to improve the accuracy of fisheries stock assessment. In this paper, we simulated the trawl trajectory under different time intervals using the cubic Hermite spline(c Hs) interpolation method based on the VMS data of 8 single otter trawl vessels(totally 36000 data items) fishing in Zhoushan fishing ground from September 2012 to December 2012, and selected the appropriate time interval. We then determined vessels’ activities(fishing or non-fishing) by comparing VMS speed data with the corresponding speeds from logbooks. The results showed that the error of simulated trajectory greatly increased with the increase of time intervals of VMS data when they were longer than 30 minutes. Comparing the speeds from VMS with those from the corresponding logbooks, we found that the vessels’ speeds were between 2.5 kn and 5.0 kn in fishing. The c Hs interpolation method is a new choice for improving the accuracy of estimation of sailing trajectory, and the VMS can be used to determine the vessels’ activities with the analysis of their trajectories and speeds. Therefore, when the fishery information is limited, VMS can be one of the important data sources for fisheries stock assessment, and more attention should be paid to its construction and application to fisheries stock assessment and management.  相似文献   

4.
The influence of Bacillus probiotics on the digestive enzyme activity and the growth of Litopenaeus vannamei were de-termined in this study. The shrimp was treated with five percentages (1.5, 3.0, 4.5, 6.0 and 7.5) of probiotics (Bacillus spp.) supple-mented to the feed and cultured for 45d. The growth measured as the weight gain at the end of culturing was significantly (P<0.05) higher in probiotic-treated shrimps than that of the control (without receiving probiotics). Activities of protease and amylase, two digestive enzymes of the midgut gland and the intestine were significantly (P<0.05) higher in probiotic-treated shrimp than in the control.  相似文献   

5.
The objective of this study is to experimentally investigate the effectiveness of Tuned Liquid Dampers (TLDs) for suppressing the dynamic response of a platform structure subjected to wave loading and to explore the applicability of TLDs for suppressing the structural vibration of fixed offshore platforms. The experimental model is scaled according to a full size platform by matching its dynamic properties. Rectangular and circular TLDs of various sizes and water depths are examined. The experiments were performed in a 2 D wave flume. The effectiveness of TLDs is evaluated based on their response reduction. By observing the performance and the behavior of TLDs through laboratory experiments, the effects of a number of parameters including container shape, container size, number of dampers, frequency ratio, mass ratio, and incident wave characteristics are investigated.  相似文献   

6.
1 .INTRODUCTIONThewesternequatorialPacific ,particularlythesouthernmostPhilippineSea ,wascalled“watermasscrossroads”byFineetal.(1 994 )duetotheconfluencethereofseveralwatermassesfromhigherlatitudesofbothhemispheres (Wyrtki,1 96 1 ;Fineetal.,1 994 ) .Fineetal.(1 994 )de picted (Fig .1 )majorcurrentsintheIndonesianregion .AfterencounteringthewesternboundaryalongthePhilippinecoast,theNorthEquatorialCur rent (NEC)bifurcatesintothenorthwardflowingKuroshioandthesouthwardflowingMindanao…  相似文献   

7.
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   

8.
Study on the dominant species of Pteropoda in East China Sea   总被引:2,自引:0,他引:2  
1 INTRODUCTION Pteropoda is a group of marine pelagic mol- lusks, which belongs to Opisthobranchia of Gastro- poda. Although Pteropoda is not a major group in pelagic zooplankton in terms of abundance and number of species, their ecological characters are…  相似文献   

9.
Filter-feeding shellfish are common benthos and significantly affect the biogeochemical cycle in the shallow coastal ecosystems.Ark clam Scapharca subcrenata is one of the widely cultured bivalve species in many coastal areas owing to its tremendous economic value.However,there is little information regarding the effects of the bioturbation of S.subcrenata on the fluxes of nutrient exchange in the sediment-water interface(SWI).In this regard,S.subcrenata was sampled during October 2016 to determine the effects of its bioturbation activity on the nutrient exchange flux of the SWI.The results showed that the biological activity of S.subcrenata could increase the diffusion depth and the rate of the nutrients exchange in the sediments.The bioturbation of S.subcrenata could allow the nutrients to permeate into the surface sediments at 6-10cm and increase the release rate of nutrients at the SWI.The releasing fluxes of DIN and PO43−-P in the culture area were found to be around three times higher than that in the non-cultured region.The culture of S.subcrenata has been proved to be an important contributor to nutrient exchange across the SWI in the farming area of Haizhou Bay.Nutrients exchange in the SWI contributes a part of 86%DIN,71%PO43−-P and 18%SiO32−-Si for the aquaculture farm.  相似文献   

10.
1 Introduction FishcageculturesystemhasbeenwidelyusedinmaricultureindustryinChina .Indesigningthecagesystem ,thewaterdragactingonit,includingthatonculturedfish ,shouldbetakenintoaccount.Avarietyofmethodshavebeenusedtodeterminethewaterdragofanimalsrangin…  相似文献   

11.
Numerical Study on Density Residual Currents of the Bohai Sea in Summer   总被引:2,自引:0,他引:2  
M2 tide and density residual currents in the Bohai Sea were examined using the Blumberg and Mellor 3D nonlinear numerical coastal circulation model incorporating,Mellor and Yamada level 2.5 turbulent closure model.The tidal results showed good agreement with previous work.The model results indicated that the density residual currents are robust in summer;and that at the transition zone between well-mixed and stratified water,the horizontal velocity is high and the vertical velocity is positive.  相似文献   

12.
The activities of some digestive enzymes are studied for Takifugu rubripes larvae and juvenile from the first feeding to 27 d after hatching at selected stages of development. The homogenate of whole larvae body is used for enzymatic determination. Activity of acid protease decreases notably during the beginning days after the commencement of completely exogenous feeding and the days before the beginning of the juvenile stage. Alkaline protease specific activity also decreases at metamorphosis, The activities are associated with the morphology of the developing digestive tract. Amylase activity increases before the first feeding, followed by a decreasing and then a rather constant level. Lipase activity remains low during the larvae and juvenile periods. Alkaline phosphatase activity increases gradually. This reflects the development of brush border membranes of enterocytes.  相似文献   

13.
In this paper, the spreading way in the southern hemisphere that anomalous warm water piled in tropical eastern Pacific is analysed and then impact of E1 Nino on the variability of the Antarctic sea ice extent is investigated by using a dataset from 1970 to 2002. The analysis result show that in E1 Nino event the anomalous warm water piled in tropical eastern Pacific is poleward propagation yet the westward propagation along southern equator current hash “t been discovered . The poleward propagation time of the anomalous warm water is about 1 year or so. E1 Nino event has a close relationship with the sea ice extent in the Amundsen sea , Bellingshausen sea and Antarctic peninsula . After E1 Nino appears , there is a lag of two years that the sea ice in the Amundsen sea , Bellingshausea sea, especially in the Antarctic peninsula decreases obviously. The processes that E1 Nino has influence with Antarctic sea ice extent is the warm water piled in tropical eastern Pacific poleward propagation along off the coast of southern America and cause the anomalous temperature raise in near pole and then lead the sea ice in Amundsen sea , Bellingshausen sea and Antarctic peninsula to decrease where the obvious decrease of the sea ice since 80’ decade has close relation to the frequently appearance of E1 Nino.  相似文献   

14.
In this study, Pearl oyster mantle type V collagen(POMC) and tilapia scale type I collagen(TSC) were extracted and hydrolyzed by various proteases in order to obtain peptides. The antioxidant activity of the peptides was investigated by DPPH, hydroxyl radical scavenging experiments and a dynamic digestion model in vitro. The results show that there are significant differences in amino acid composition between POMC and TSC. The collagen peptides obtained from pearl oyster mantle(POMCP) by treating with alkaline protease exhibited higher antioxidant activity than that from tilapia scale(TSCP) treated with papaya protease, and both of them showed greater DPPH and hydroxyl radical scavenging activity than other peptides. After being separated via Sephadex G-25 chromatography, the M1 fraction isolated from POMCP, and the S1 fraction from TSCP with which both had higher molecular weights showed the strongest antioxidant activity than other fractions, and the M1 fraction exhibited stronger antioxidant activity than the S1 fraction in scavenging free-radicals and protecting cells from the oxidation damage. Furthermore, after treating the dynamic digestion system model in vitro, the DPPH and hydroxyl radical scavenging activity of the M1 fraction increased slightly. These results suggest that POMCP exhibits stronger antioxidant activity than TSCP, which means that PMOP may be a good candidate to be a potential natural antioxidant in the food-processing industry.  相似文献   

15.
INTRODUCTIONTheYellowSeaandtheEastChinaSea (ECS)aremarginalseasofthenorthwestPacificandhaveexpansivecontinentalshelves .TheuniqueandstrikingfeaturesoftheYellowSeaandtheECSarethattheyhavestrongtidalcurrent;aresubjecttostrongmonsooninfluence ;andreceiveinflowfromthebiggestriverinChina ,theChangjiangRiver ;andthatthefamouswesternboundarycurrent,theKuroshio ,passesthroughtheECS ,withitsbranchesintrudingupwardintothecontinentalshelfareas.Generallyspeaking ,thewaterexchangecapacityofthe…  相似文献   

16.
The effects of environmental Na /K ratio on the gill ion-transport enzyme activity,plasma osmolality and growth ofCynoglossus semi/aevis juveniles were investigated.The results showed that,plasma osmolality was similar among flounder adaptedto different Na /K ratios of saline groundwaters (P>0.05),while the growth,gill Na ,K -ATPase and HCO,3'--ATPase activities wereaffected by Na /K ratio significantly (P<0.05).The gill Na ,K -ATPase activity reached its maximum on day 3,then decreasedgradually from day 3 to day 9 and remained constant from day 9 to day 15.The peak values of gill Na ,K -ATPase activity weredetected on day 3 for all Na /K ratios of saline groundwaters,then the enzyme activities descended,and on day 9 the enzyme activi-ties achieved steady state,and the gill HCO,3--ATPase activity increased rapidly and achieved steady state after one day.Duringsteady state,the gill Na ,K -ATPase and HCO,3--ATPase activity of Na /K ratios 20 and 40 treatments were significantly higherthan those in the control group (Na /K ratio 27.5),while there were no significant differences between the Na /K ratio 30 treatmentand the control group; the gill Na ,K -ATPase activity of Na /K ratio 20 and 40 treatments were significantly higher than that forratio 30 treatment,but there were no significant differences of gill HCO3-ATPase activity among these treatments.At the end of the15-day experiment,the weight gain (%) and specific growth rate (SGR) of flounders maintained in seawater were significantly higherthan those in groundwaters; significant differences also occurred among the treatments; Na /K ratio 30 treatment had the highestvalues (33.7% and 1.94 respectively),which were significantly higher than those under Na /K ratios 20 and 40 treatments.There-fore,for the saline groundwater used in this experiment,it is suggested that the Na /K ratio be adjusted to approximately 30,I.e.,asclose to that of natural seawater as possible in the culture of flounder.  相似文献   

17.
N-(2-hydroxy-1-naphthaldene)-4-aminoantipyrine has been synthesized. The structure is determined by X-ray diffraction method and elemental analysis. The crystal system belongs to orthorhombic space group P(2)2(1)2(1). The geometry has been ob-tained from the density functional theory (DFT) method and the B3LYP method employing the 6-31G* basis sets. The calculated results propose that the latter is close to the experimental data. The structural parameters from the theory are close to those of the crystal and the calculated total energy of coordination is -31677.172 eV. The energy of HOMO and LUMO and the energy gap are 5.179 eV, -1.603 eV and 3.577 eV, respectively.  相似文献   

18.
Myosin subfragment-1 was prepared from the myofibrils of bighead carp (Aristichthys nobilis). The myosin subfrag- ment-1 was proved to have the activity of tripolyphosphatase (TPPase) responding to the hydrolysis of sodium tripolyphosphate (STPP). The optimum temperature and pH for the TPPase of myosin subfragment-1 were 30℃ and pH 5.0, and at pH 8.0 the TPPase also showed a high activity. Mg2 was necessary to TPPase. The TPPase activity of myosin subfragment-1 was activated by Mg2 under low concentrations, but was inhibited when the concentration was over 17 mmolL-1. The TPPase activity was also affected by KCl. The optimum concentration of KCl for TPPase was 0.3 molL-1 under the condition of 17 mmolL-1 Mg2 . The TPPase activity was significantly inhibited by EDTA-Na2. Reagents such as KBr, KI and KIO3 could inhibit the TPPase effectively. K2Cr2O7 as well as KMnO7 and KNO3 exhibited weak inhibiting effects. The TPPase converted STPP to pyrophosphate (PP) and orthophosphate (Pi) stoichiometrically with a KM of 3.2 mmolL-1.  相似文献   

19.
A new kinetic spectrophotometric method has been developed for the determination of trace Ni (II) in natural water.The method is based on the catalytic effect of Ni (II) on the oxidation of weak acid brilliant blue dye (RAWL) by KIO4 in acid medium.The concentration of nickel (II) can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ= 626 nm using the fix-time method.The influencing factors are investigated by the orthogonal experimental design.The obtained optimum analytical conditions are:pH=2.00,c RAWL=5.00×10-5 mol L-1,cKIO 4= 2.00×10-5 mol L-1,the reaction time t=10 min and the temperature T=25℃..Under the optimum conditions,the developed method allows the measurement of Ni (II) in a range of 0-40.0 ng mL-1.The standard deviation of eleven independent measurements of blank reaction is S=3.08×10-3 and the limit of detection is 2.20 ng mL-1.The relative standard deviations (RSDs) in six replicate determinations of 5 ng mL-1 and 8 ng mL-1 Ni (II) are 2.87% and 1.11%,respectively.Moreover,the experiments show few cations and anions can interfere with the measurement of Ni (II).The recovery efficiencies of this method are in a range of 97.0%-102.5% in freshwater samples.But there is a decreasing effect,which is about 0.2 times the added Ni (II) in seawater medium.After reasonable calibration this processing method is used for the determination of Ni (II) in seawater samples successfully.The results show this developed method has high accuracy and precision,high sensitivity,large range of linearity and high speed.The method can,therefore,be employed at room temperature.  相似文献   

20.
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   

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