本文關(guān)鍵詞： 受限空間 廣義郎之萬方程 模耦合理論 多孔介質(zhì) 活性粒子 動力學(xué)不均一　出處：《中國科學(xué)技術(shù)大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：隨著生命和納米科學(xué)技術(shù)的不斷發(fā)展,介觀尺度(一般來說,介觀尺度的范圍大約在10nm～1μm之間)中粒子動力學(xué)的研究因其重要性受到了越來越多的關(guān)注。通常,介觀體系(如細(xì)胞,離子通道等)具有非常復(fù)雜的內(nèi)部結(jié)構(gòu)和運(yùn)動學(xué)特征。從結(jié)構(gòu)上看,細(xì)胞、離子通道具有空間受限的特征,而其中存在的大量有機(jī)物質(zhì)又使得其表現(xiàn)出多孔介質(zhì)的特點(diǎn)。從運(yùn)動學(xué)角度上看,細(xì)胞等有機(jī)體具有將周圍環(huán)境能量轉(zhuǎn)換成定向驅(qū)動力的能力。因此,這些介觀系統(tǒng)的內(nèi)在結(jié)構(gòu)和運(yùn)動特征可以導(dǎo)致復(fù)雜多變的動力學(xué)行為,例如粒子定向輸運(yùn),復(fù)雜環(huán)境高分子異常擴(kuò)散和膠粒相分離等。這些問題往往不能用簡單的統(tǒng)計力學(xué)方程定量描述和理論分析,因此理論結(jié)合適當(dāng)?shù)奈锢砟Ｐ瓦M(jìn)行計算機(jī)模擬成了研究這一類介觀體系動力學(xué)的重要技術(shù)方法。本文以介觀體系中經(jīng)常遇到的納米粒子和高分子作為主要研究對象,采用理論結(jié)合模擬的手段研究介觀體系中受限、多孔及活性等復(fù)雜環(huán)境對納米尺度物質(zhì)擴(kuò)散動力學(xué)的影響�！袷芟蘅臻g粒子擴(kuò)散動力學(xué)近二三十年來,受限空間粒子擴(kuò)散的研究因其重要性和在實(shí)際介觀系統(tǒng)中的應(yīng)用一直都是物理、化學(xué)和生命科學(xué)關(guān)注的前沿問題。在軟凝聚物及生命系統(tǒng)中,存在著大量狹長的通道,物質(zhì)必須通過這些通道到達(dá)指定位置從而實(shí)現(xiàn)其功能。本文重點(diǎn)考察了隨時間變化的通道中納米粒子的兩個重要動力學(xué)行為,熵隨機(jī)共振和粒子定向輸運(yùn)。研究表明變化的通道對粒子的動力學(xué)產(chǎn)生了顯著的影響,主要表現(xiàn)為:隨機(jī)共振強(qiáng)度和粒子輸運(yùn)速度隨粒子重力有著非單調(diào)的變化趨勢。這些現(xiàn)象在靜止邊界的通道中是無法觀測到的。我們利用粗�；拿枋鍪侄�,將通道對粒子運(yùn)動的影響在一定的時間和空間尺度上等效成熵壘的作用,發(fā)現(xiàn)粒子在變化通道中受到了來自通道產(chǎn)生的有效熵力的作用。通過對有效熵力的分析,很好的解釋了變化通道中觀測到的熵隨機(jī)共振及粒子輸運(yùn)對重力的非平凡的依賴行為。我們還進(jìn)一步研究了其它與通道特征有關(guān)的物理量,例如振蕩振幅、頻率、相差、對稱性等對熵隨機(jī)共振及粒子輸運(yùn)的影響。●復(fù)雜環(huán)境高分子擴(kuò)散動力學(xué)細(xì)胞等復(fù)雜環(huán)境中存在著大量的物質(zhì),如肌動蛋白纖維、核糖體、t-RNA和m-RNA等,這些物質(zhì)的存在會對其中高分子的擴(kuò)散及結(jié)構(gòu)動力學(xué)產(chǎn)生重要的影響。例如,其中障礙物粒子的存在會降低酶的催化作用,提高RNA的穩(wěn)定性甚至是它的熔點(diǎn),還可以阻礙DNA綁定蛋白的遷移等等。而高分子在這樣一種具有大量復(fù)雜物質(zhì)的環(huán)境中的擴(kuò)散問題也是生物物理及化學(xué)研究的重要課題之一。在本文中,通過結(jié)合模耦合理論和描述高分子運(yùn)動的廣義郎之萬方程,我們從理論上研究了多孔介質(zhì)環(huán)境中高分子的擴(kuò)散及結(jié)構(gòu)動力學(xué)行為。研究結(jié)果表明,在多孔介質(zhì)這樣擁擠的環(huán)境中,高分子出現(xiàn)了異常擴(kuò)散行為,且末端距漲落的冪率衰減現(xiàn)象也與在一般環(huán)境中的高分子存在著時間尺度上的行為差異。進(jìn)一步的研究表明了多孔介質(zhì)中基底粒子(無法運(yùn)動的粒子)的存在是導(dǎo)致異常擴(kuò)散的主要原因,因為基底粒子的存在導(dǎo)致的系統(tǒng)平移不變性的消失使得高分子所感受到的記憶摩擦核出現(xiàn)了長尾衰減的行為,以此我們也證實(shí)了基底粒子對高分子動力學(xué)的影響要遠(yuǎn)遠(yuǎn)強(qiáng)于可運(yùn)動的流體粒子�！窕钚粤Ｗ臃瞧胶鈩恿W(xué)活性粒子是指那些能將周圍環(huán)境的能量轉(zhuǎn)換成自身驅(qū)動力而具有定向運(yùn)動能力的人工合成納米粒子。在最近幾年中,由于材料學(xué)和納米科學(xué)的蓬勃發(fā)展,具有各種功能和形狀的活性粒子層出不窮。由于粒子的活性可以推動體系遠(yuǎn)離平衡態(tài),因此導(dǎo)致了活性粒子體系的大量有趣現(xiàn)象,如粒子集群運(yùn)動、流體力學(xué)作用下的粒子自旋反轉(zhuǎn)、體系相分離等。基于這些有趣的非平衡現(xiàn)象,自組裝的研究也因此得到了長足的發(fā)展。近來,人們開始從理論及模擬上著手研究粒子活性在玻璃態(tài)轉(zhuǎn)變過程中所扮演的角色,其中體系的動力學(xué)不均一行為因其重要性受到了特別的關(guān)注。在本文中,我們利用描述活性粒子的過阻尼郎之萬方程詳盡的研究了粒子活性對體系動力學(xué)不均一的影響。經(jīng)研究發(fā)現(xiàn),較高粒子體積分?jǐn)?shù)下體系的動力學(xué)不均一程度隨著活性的增加表現(xiàn)出了非單調(diào)的變化,進(jìn)一步的研究使得我們還發(fā)現(xiàn)在粒子活性較大時,隨著粒子體積分?jǐn)?shù)的增加,體系的動力學(xué)不均一也表現(xiàn)出非單調(diào)變化的行為。上述這些非單調(diào)變化都說明了一個結(jié)論,即粒子活性在體系非平衡動力學(xué)過程中扮演了兩種不同的角色,它們分別是活性導(dǎo)致的體系有效高溫和活性誘導(dǎo)的粒子之間有效相互作用力。
[Abstract]:With the continuous development of life and nano science and technology, meso scale (generally, the range of meso scale at about 10nm ~ 1 m) in the study of particle dynamics has attracted more and more attention because of its importance. Usually, the mesoscopic system (such as cell ion channels, etc.) with internal structure and kinematic characteristics are very complicated. Look from the structure, characteristics of cells, ion channels have limited space, of which a large number of organic matter exists and makes it show the characteristics of porous media. From the kinematic point of view, such as cell of the organism will convert the energy into the surrounding environment the ability of directional driving force. Therefore, the internal structure and movement characteristics of these mesoscopic systems can lead to complex dynamic behavior, such as particle transport, molecular diffusion and particle complex environment of abnormal phase separation and so on. These problems can not be used to Jane The statistical mechanics equation of quantitative description and theoretical analysis, the theory combined with physical models of the computer simulation technology has become an important method to study this kind of mesoscopic system dynamics. In this paper, mesoscopic systems are often encountered in the nanoparticles and polymer as the main research object, restricted by combining theory with simulation method to study the influence of mesoscopic system. The activity of porous and complex environment such as diffusion kinetics on the nano scale material. The limited space particle diffusion dynamics in recent twenty or thirty years, study on confined space particle diffusion due to its importance and application in practice in mesoscopic systems has always been a frontier problem concerns physics, chemistry and life science. In soft condensed matter and life in the system, there is a narrow channel, so as to realize the function of the material must arrive at the designated location through these channels. This paper focus Two important dynamical behavior of nanoparticles changes with time in the channel of the entropic stochastic resonance and particle transport. The research showed that significantly influenced the dynamics of particle channel, mainly as follows: stochastic resonance intensity and particle transport velocity with particle gravity vary. These non monotonic trend in static boundary channel is not observed. We use a coarse-grained description method, will affect the channel on the motion of particles in a certain time and space scale equivalent to the entropy barrier, found by the effective particle force generated from entropy changes in the channel in the channel. Through the analysis of the effective entropy force, a good explanation of the entropic stochastic resonance and change channel observed in particle transport on the gravity of non trivial dependence behavior. We also further studies and other channels The relevant physical characteristics, such as amplitude, frequency, phase difference, symmetry transport effect on entropy stochastic resonance and particles. There are a lot of material dynamics of cell in complex environment - diffusion complex environment such as polymer, F-actin, ribosome, t-RNA and m-RNA, the presence of these substances will produce the the important effect of diffusion and kinetics of polymer structure. For example, the obstacle particles can reduce the enzyme catalysis, improve the stability of RNA and its melting point, can also hinder the migration of DNA binding protein and so on. One of the important topics of polymer diffusion problems in such a complex with a large number of substances in the environment is the bio physical and chemical research. In this paper, by combining the generalized Lang Zhiwan equation coupled mode theory and describe the motion of the polymer, we theoretically study the The diffusion and the structural dynamics behavior of polymer in porous media in the environment. The results of the study show that, in such a crowded environment in porous medium, the polymer abnormal diffusion behavior, the power fluctuation rate Qiemo end distance attenuation phenomenon and polymer in the general environment there are differences on time scales. Further studies show that the basement the particles in porous media (no moving particle) is the main cause of the abnormal diffusion, because the system shift invariance due to the existence of the substrate particles disappear makes polymer feel memory friction nuclear decay behavior appeared in the long tail, so we also confirmed the effect of substrate particles on the polymer dynamics is much stronger in the fluid movement. The particles can be activated particles non kinetic activity particle equilibrium refers to those of the surrounding environment can be converted into their own energy drive The artificial synthesis of nanoparticles with force capability. The directional movement in recent years, due to the vigorous development of material science and nano science, active particles with various functions and shapes. The particle emerge in an endless stream activity can promote the system away from equilibrium, thus leading to a large number of interesting activity particle systems, such as particle cluster motion spin reversal fluid mechanics under the action of the phase separation of the system. These interesting non-equilibrium phenomena based on self-assembly research has also been considerable development. Recently, people started from theory and simulation to research the particle activity played in the course of glass transition in the role, which the system dynamics is not uniform behavior because of the importance of particular attention. In this paper, we use the Wan Fangcheng Lang description of active particle damping exhaustive research on particle live Influence of heterogeneity on system dynamics. The study found that the kinetics of high particle volume fraction under the system heterogeneity with the increased activity shows a non monotonous variation, makes further study we also found that the activity of particles is larger, with the increase of particle volume fraction, the system dynamics is not uniform performance a non monotonic behavior. These non monotonic changes are explained to a conclusion, namely particle activity in the system of non equilibrium dynamics in the process of playing two different roles, they are between the induction system of high temperature and effective activity caused by the effective particle interactions.

【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TB383.1;O631

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