南京大学学报(自然科学版)
南京大學學報(自然科學版)
남경대학학보(자연과학판)
JOURNAL OF NANJING UNIVERSITY(NATURAL SCIENCES)
2014年
6期
873-882
,共10页
陈梅英%欧忠辉%卓艳云%陈锦权%林河通%冯力
陳梅英%歐忠輝%卓豔雲%陳錦權%林河通%馮力
진매영%구충휘%탁염운%진금권%림하통%풍력
相场法%冰晶生长%界面厚度%各向异性%过冷度
相場法%冰晶生長%界麵厚度%各嚮異性%過冷度
상장법%빙정생장%계면후도%각향이성%과랭도
phase-field%crystal growth%interface thickness%anisotropic%degree of supercooling
水溶液冻结过程生成的冰晶是低温保存中造成细胞损伤的主要原因.研究如何降低冰晶形成和生长过程对细胞伤害的方法,是低温生物研究的重要课题.本文采用国内外描述相变微观结构的相场模型,将体系视为水和溶质二元系统,研究了界面厚度尺度、各向异性强度和过冷度对结晶过程冰晶生长的影响.结果表明:界面厚度影响模拟结果,为了获得可靠的计算结果,界面厚度参数取值为3.00 dx;各向异性系数大小对冰晶形貌有很大影响,取值越大,冰晶的二次分枝越发达,且尖端速度波动的幅值越大,各向异性系数取值范围0.010~0.025;过冷度明显影响冰晶的生长和形貌,过冷度大,冰晶生长速度加快,二次分枝发达,形貌变化较大,固相率也随之变大.参数优化结果为:界面厚度尺度等于3.00 dx,各向异性系数等于0.023,过冷度等于20 K 的模拟结果与低温显微镜下观察到的冰晶生长形貌试验结果相吻合.
水溶液凍結過程生成的冰晶是低溫保存中造成細胞損傷的主要原因.研究如何降低冰晶形成和生長過程對細胞傷害的方法,是低溫生物研究的重要課題.本文採用國內外描述相變微觀結構的相場模型,將體繫視為水和溶質二元繫統,研究瞭界麵厚度呎度、各嚮異性彊度和過冷度對結晶過程冰晶生長的影響.結果錶明:界麵厚度影響模擬結果,為瞭穫得可靠的計算結果,界麵厚度參數取值為3.00 dx;各嚮異性繫數大小對冰晶形貌有很大影響,取值越大,冰晶的二次分枝越髮達,且尖耑速度波動的幅值越大,各嚮異性繫數取值範圍0.010~0.025;過冷度明顯影響冰晶的生長和形貌,過冷度大,冰晶生長速度加快,二次分枝髮達,形貌變化較大,固相率也隨之變大.參數優化結果為:界麵厚度呎度等于3.00 dx,各嚮異性繫數等于0.023,過冷度等于20 K 的模擬結果與低溫顯微鏡下觀察到的冰晶生長形貌試驗結果相吻閤.
수용액동결과정생성적빙정시저온보존중조성세포손상적주요원인.연구여하강저빙정형성화생장과정대세포상해적방법,시저온생물연구적중요과제.본문채용국내외묘술상변미관결구적상장모형,장체계시위수화용질이원계통,연구료계면후도척도、각향이성강도화과랭도대결정과정빙정생장적영향.결과표명:계면후도영향모의결과,위료획득가고적계산결과,계면후도삼수취치위3.00 dx;각향이성계수대소대빙정형모유흔대영향,취치월대,빙정적이차분지월발체,차첨단속도파동적폭치월대,각향이성계수취치범위0.010~0.025;과랭도명현영향빙정적생장화형모,과랭도대,빙정생장속도가쾌,이차분지발체,형모변화교대,고상솔야수지변대.삼수우화결과위:계면후도척도등우3.00 dx,각향이성계수등우0.023,과랭도등우20 K 적모의결과여저온현미경하관찰도적빙정생장형모시험결과상문합.
The main cause of cell damage in aqueous solution was ice crystals generated by low temperature preservation.It is an important topic for low temperature biology research to study how to reduce the cell damage from ice crystal formation and growth.In order to investigate the influence on correlative parameters such as interface thickness,anisotropic and degree of supercooling,by regarding system as water and solute in binary system,the phase-field model theory which had been widely used in the phase transition of the microscopic structure at home and abroad was employed to stimulate the ice growth process.The results showed that the interface thickness had influence on the simulation results.It should be taken a reasonable value of 3.00 dx to get reliable cal-culation results.The anisotropic coefficient had a great influence on the crystal morphology.When it became bigger, the secondary dendritic branches of ice crystals were better-developed and the fluctuation amplitude of tip growth speed would be intensified ranging from 0.010 to 0.025.The degree of supercooling significantly affected the growth and morphology of the ice crystals.The growth speed of ice crystal would increase by the larger degree of supercooling and the secondary dendritic branches of ice crystals were better-developed,the morphology and the solid fraction would have greater change too.The conclusion of the optimization results of the interface thickness was 3.00 dx,the anisotropic coefficient was 0.023 and super-cooling degree was 20 K.It would validate the simulation results coincided well with the experiment.