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1、東北石油大學本科生畢業(yè)設計(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結(jié)晶的表面形貌。利用原子力顯微鏡從介觀尺度上對不同影響因素下NaCl溶液結(jié)晶樣品進行了觀察,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NaCl溶液結(jié)晶過程的影響,并對其成形機制和分形維數(shù)進行了探討。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越高,生成的枝叉狀結(jié)構(gòu)越來越大,并且結(jié)晶中有許多立方體結(jié)構(gòu)。比較結(jié)晶花樣的
2、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,晶體長得細小,且往往長成針狀、樹枝狀。反之,結(jié)晶速率小,晶體長得粗大。表面平整度影響著結(jié)晶的表面形貌。而且,表面的平整度會影響溶液的流動,從而影響NaCl晶粒的聚集行為,對分形花樣的形成起到一定的作用。關(guān)鍵詞:NaCl溶液;結(jié)晶;分
3、形維數(shù);擴散受限聚集機制東北石油大學本科生畢業(yè)設計(論文)AbstractThesurfacetopographyofsodiumchloridesolutionscrystallizationwasstudiedindifferentinitialconcentration,differenttemperatureanddifferentbasement.Thesurfacetopographyofsodiumchloridesolutionscrystallizationsampleswereobservedfrom
4、mesoscaleunderdifferentaffectingfactorsbyatomicforcemicroscope,andusingtheImage-proPlustoprocessingthescanimages.Analyzingtheinfluenceoftheseveralfactorstotheprocessofsodiumchloridesolutionscrystallization,theformingmechanismandthefractaldimensionwerediscussed.Th
5、eresultsofthestudyshowthattheloweroftheinitialconcentrationofthesodiumchloridesolutions,themoretendtogeneratedendriticstructurefractalpatternconsistingofsmallcrystalparticles.Alongwiththeincreaseoftheinitialconcentrationofthesodiumchloridesolutions,theaggregation
6、degreeofthefractalpatternofcrystallizationwasincreasedandformingbiggerdendriticstructure.Whatmore,thereismuchmorecubicstructureinthecrystallization.Comparingthefractaldimensionofthecrystallizationpattern,anditisfoundedthatthefractalpatterndimensionoftheloweriniti
7、alconcentrationcrystallizationwassimilartoKochcurve,andthefractalpatterndimensionofthehigherinitialconcentrationcrystallizationwasconsistentwiththediffusion-limitedaggregationmodel.Astheincreaseoftheinitialconcentrationofthecrystallization,thefractaldimensionincr
8、easesgradually.Thetemperatureinfluencesthecrystallizationrate.Thehigherthecrystallizationrate,themorethecrystallizationcenterandthemoretendencyofthecrystalliza