简介:Euphausiapacificisanimportantsourceofnaturalastaxanthin.StudieswerecarriedouttoassesstheextractabilityofastaxanthinfromE.pacificusingsubcritical1,1,1,2-tetrafluoroethane(R134a).Toexaminetheeffectsofmultipleprocessvariablesontheextractionyield,astaxanthinwasextractedundervariousconditionsofpressure(30-150bar),temperature(303-343K),time(10-50min),flowrate(2-10gmin-1),moisturecontent(5.5%-63.61%),andparticlesize(0.25-0.109mm).Theresultsshowedthattheextractionyieldincreasedwithtemperature,pressure,timeandflowrate,butdecreasedwithmoisturecontentandparticlesize.Amaximumyieldof87.74%wasobtainedunderconditionsof100bar,333K,and30minwithaflowrateof6gmin-1andamoisturecontentof5.5%.Thesubstantialastaxanthinyieldobtainedunderlow-pressureconditionsdemonstratesthatsubcriticalR134aisagoodalternativetoCO2forextractionofastaxanthinfromE.pacific.
简介:以覆盖黄河三角洲和连云港区域的两景高分一号卫星遥感影像1A级产品为例,利用现场采集的地面控制点和1∶50000的DEM产品,开展了影像自主定位和正射校正实验,制作了控制点偏移矢量图,并对影像的定位精度进行了分析.结果表明:高分一号卫星影像具有较好的自主定位精度,黄河三角洲区域影像定位精度在27.8m左右,连云港区域影像定位精度在53.8m左右;在单控制点的情况下,影像的定位精度在3m左右,最大偏移量约为6m;在多控制点下正射校正,影像的定位精度为1m左右,最大偏移量为1个像元;对比控制点偏移矢量图,检查点较影像同名点的偏移方向与大小基本一致,表明高分一号卫星影像内部刚性较好.
简介:TheenvironmentalconditionsaroundthefirstoffshoreHZ21-1steelwellheadplatformintheSouthChinaSeaarecharacterizedbydeepwater,frequenttyphoons,roughwaves,highwatertemperature,severelycorrosiveseawater,andthickfoulingorganismattachments.Thedesignandeffectivenessofgalvanicanodeprotectionsystemarepresented,andseveralmethodsaredescribed,whicharethecalculationmethodoftheprotectivecurrentdensityconsideringthevariationofwaterdepth,themethodofdeterminingprotectionparametersconsideringvariousfactors,thearrangementofanodesbasedonpotentialdistributionandcurrentrequirementsatdifferentwaterdepths,andthemethodofanodeinstallation.Finallytheeffectoftheaccuracyofselectedcathodicprotectionparametersontheeconomicbenefitsofoffshoreprojectsisalsodiscussed..
简介:TheHY-1AsatelliteisthefirstoceanicsatelliteofChina.Duringthewinterof2002~2003,thedataoftheHY-1AwereappliedtotheseaicemonitoringandforecastingfortheBohaiSeaofChinaforthefirsttime.TheseaiceretrievalsystemoftheHY-1Ahasbeenconstructed.Itreceives1Bdatafromthesatellite,outputsseaiceimagesandprovidesdigitalproductsoficeconcentration,icethicknessandiceedge,whichcanbeusedasimportantinformationforseaicemonitoringandtheinitialfieldsofthenumericseaiceforecastandasoneofthereferencedatafortheseaiceforecastingverification.Theseaiceretrievalsystemofthesatelliteisdescribed,includingitsprocesses,methodsandparameters.TheretrievingresultsandtheirapplicationtotheseaicemonitoringandforecastingfortheBohaiSeaarealsodiscussed.
简介:虽然许多注意被给了描述波浪的模型,潮和沉积运输在足够的详细处理决定在床上的本地变化在深测术的一个相对详细的代表上铺平,远,更少的注意被给了在大得多的规模考虑这个问题的模型(例如象一条潮汐的扁平、潮汐的隧道那样的geomorphological元素的)。这聚集了或lumped模型趋于不表示这些过程详细,但是相当在兴趣的规模捕获行为。如此的模型用平衡集中的概念开发了的是聚集的规模在潮汐的盆和邻近的海岸(ASMITA)之间的词法相互作用。在这份报纸,我们提供一些新卓见进平衡,和是这条建模途径的关键部件的水平、垂直的交换的概念。在一份同伴报纸,我们总结被承担了扩大原来的模型概念的开发的一个范围,到说明概念的框架的灵活性和力量。然而,日益增多地增加详细在详细基于过程的模型和我们给某考虑到在二之间的边界的更多的方向感动模特儿。聚集模型规模的HighlightsThe概念被探索,ASMITA模型的基础详细被构画出在在快规模的基于过程的模型和在聚集的模型使用的水平交换使用了的分散之间的关系被探索提出合适的平衡关系的基础被解释其他的方法包括移流和分散检验。
简介:Cytarabine(1-β-D-arabinofuranosylcytosine,Ara-C),isolatedfromaCaribbeanspongespeciesTethyacrypta,isthefirstantitumordrugfromamarineresource.In1980,theUSFoodandDrugAdministrationapprovedthisdrugforthetreatmentofdifferenttypesofleukemia.Thisdrughasashortplasmahalf-life,lowstability,limitedbioavailability,andseveresideeffects.Toimprovestabilityandbioavailability,wesynthesizedninenovelderivativesbyblockingthecytarabinemetabolicsitesandimprovinglipophilicity.ThecLogPvaluesofthenewlysynthesizedcompoundswerecalculated.Allthesynthesizedcompoundsweremorelipophilicthancytarabine,resultinginmembranepermeabilityandbioavailabilityimprovement.TheantitumoractivitiesagainstleukemiacelllineHL-60wereevaluatedbyusingtheMTTassay.ThebioassayresultsrevealedthattheIC50valuesofcompounds5,8and9were0.080,0.090and0.057μmolL-1,respectively,whichwassimilarwiththatofcytarabine(0.056μmolL-1).Incomparison,compound4withaphosphategroupatO5’wasinactive.Becausephosphoesterbondsareeasilyhydrolyzedbyalkalinephosphataseandarecommonlyusedinproducingprodrugstrategies,compound4mightalsobemetabolizedinvivoandgeneratecompound3orevencytarabinethroughamulti-stepreaction.Thus,compound4mightbeapromisingcompoundtobedevelopedasaprodrug.