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1、東北石油大學(xué)本科生畢業(yè)設(shè)計(jì)(論文)摘要研究了NaCl溶液在不同初始濃度、不同溫度和不同基底時(shí)結(jié)晶的表面形貌。利用原子力顯微鏡從介觀尺度上對(duì)不同影響因素下NaCl溶液結(jié)晶樣品進(jìn)行了觀察,利用圖像處理軟件Image-proPlus處理掃描圖像,分析了這幾種因素對(duì)NaCl溶液結(jié)晶過(guò)程的影響,并對(duì)其成形機(jī)制和分形維數(shù)進(jìn)行了探討。研究結(jié)果表明,初始濃度越低,結(jié)晶分形花樣越傾向于生成由細(xì)小的晶體顆粒組成的樹枝狀結(jié)構(gòu)。隨著初始濃度的增大,結(jié)晶分形花樣聚集程度越來(lái)越高,生成的枝叉狀結(jié)構(gòu)越來(lái)越大,并且結(jié)晶中有許多立方體結(jié)構(gòu)
2、。比較結(jié)晶花樣的分形維數(shù),發(fā)現(xiàn)較低初始濃度結(jié)晶的分形花樣的分形維數(shù)與Koch曲線類似,較高初始濃度結(jié)晶的分形花樣的分形維數(shù)符合擴(kuò)散受限聚集(Diffusion-limitedaggregation,DLA)模型的結(jié)果。隨著結(jié)晶初始濃度的增大,分形維數(shù)逐漸增大。溫度影響了結(jié)晶的速率,結(jié)晶速率大,則結(jié)晶中心增多,晶體長(zhǎng)得細(xì)小,且往往長(zhǎng)成針狀、樹枝狀。反之,結(jié)晶速率小,晶體長(zhǎng)得粗大。表面平整度影響著結(jié)晶的表面形貌。而且,表面的平整度會(huì)影響溶液的流動(dòng),從而影響NaCl晶粒的聚集行為,對(duì)分形花樣的形成起到一定的作用
3、。關(guān)鍵詞:NaCl溶液;結(jié)晶;分形維數(shù);擴(kuò)散受限聚集機(jī)制東北石油大學(xué)本科生畢業(yè)設(shè)計(jì)(論文)AbstractThesurfacetopographyofsodiumchloridesolutionscrystallizationwasstudiedindifferentinitialconcentration,differenttemperatureanddifferentbasement.Thesurfacetopographyofsodiumchloridesolutionscrystallizatio
4、nsampleswereobservedfrommesoscaleunderdifferentaffectingfactorsbyatomicforcemicroscope,andusingtheImage-proPlustoprocessingthescanimages.Analyzingtheinfluenceoftheseveralfactorstotheprocessofsodiumchloridesolutionscrystallization,theformingmechanismandthe
5、fractaldimensionwerediscussed.Theresultsofthestudyshowthattheloweroftheinitialconcentrationofthesodiumchloridesolutions,themoretendtogeneratedendriticstructurefractalpatternconsistingofsmallcrystalparticles.Alongwiththeincreaseoftheinitialconcentrationoft
6、hesodiumchloridesolutions,theaggregationdegreeofthefractalpatternofcrystallizationwasincreasedandformingbiggerdendriticstructure.Whatmore,thereismuchmorecubicstructureinthecrystallization.Comparingthefractaldimensionofthecrystallizationpattern,anditisfoun
7、dedthatthefractalpatterndimensionofthelowerinitialconcentrationcrystallizationwassimilartoKochcurve,andthefractalpatterndimensionofthehigherinitialconcentrationcrystallizationwasconsistentwiththediffusion-limitedaggregationmodel.Astheincreaseoftheinitialc
8、oncentrationofthecrystallization,thefractaldimensionincreasesgradually.Thetemperatureinfluencesthecrystallizationrate.Thehigherthecrystallizationrate,themorethecrystallizationcenterandthemoretendencyofthecrystalliza