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回復(fù)性是動(dòng)力系統(tǒng)中最重要的概念之一，它不僅對(duì)動(dòng)力系統(tǒng)的研究起到基礎(chǔ)性的作用，而且在其它數(shù)學(xué)學(xué)科（例如，組合、數(shù)論等）中有不平凡的應(yīng)用。在報(bào)告中我們將回顧回復(fù)性與其應(yīng)用的一些經(jīng)典結(jié)果，同時(shí)將介紹研究中用到的一些工具、最新的研究成果和一些未解決的問(wèn)題。

智能材料與結(jié)構(gòu)是一類在外界激勵(lì)下可以做出主動(dòng)響應(yīng)的新型材料與結(jié)構(gòu)，具有主動(dòng)大變形、變剛度、控制方式多樣、可重復(fù)使用、可大尺寸成型等特點(diǎn)，在航天航空、生物醫(yī)療、電子器件等領(lǐng)域顯示出了巨大的應(yīng)用潛力與實(shí)用價(jià)值。智慧材料和人工智能的交叉研究將引領(lǐng)航空航天、智能制造、生物醫(yī)療和機(jī)器人等領(lǐng)域發(fā)展的新方向，為未來(lái)構(gòu)造智能社會(huì)提供物質(zhì)基礎(chǔ)和保障。本報(bào)告將圍繞典型智能材料，介紹其在空天領(lǐng)域的新思路和新成果。

石墨烯與層狀材料在光子學(xué)與光電子學(xué)領(lǐng)域展現(xiàn)出巨大潛力。在這些領(lǐng)域中，它們的光學(xué)與電學(xué)特性得以充分結(jié)合，并且石墨烯無(wú)帶隙的特點(diǎn)亦可轉(zhuǎn)化為優(yōu)勢(shì)。石墨烯中狄拉克電子的線性色散關(guān)系，使其能夠?qū)崿F(xiàn)超寬譜帶的可調(diào)諧性，以及通過(guò)柵壓調(diào)控、在超寬帶寬內(nèi)實(shí)現(xiàn)三次諧波增強(qiáng)，這為光通信與信號(hào)處理領(lǐng)域所需的電可調(diào)寬帶頻率轉(zhuǎn)換器開(kāi)辟了道路。由于泡利阻塞效應(yīng)，石墨烯中可觀察到可飽和吸收現(xiàn)象，該特性可被用于實(shí)現(xiàn)多種超快與寬帶激光器的鎖模運(yùn)作。石墨烯集成光子學(xué)為下一代數(shù)據(jù)通信與電信中所需的調(diào)制器、探測(cè)器和開(kāi)關(guān)的晶圓級(jí)制造提供了一個(gè)平臺(tái)。這些功能可通過(guò)將石墨烯層置于作為無(wú)源光波導(dǎo)的光波導(dǎo)頂端來(lái)實(shí)現(xiàn)，從而簡(jiǎn)化現(xiàn)有技術(shù)。基于多種原子晶體的異質(zhì)結(jié)構(gòu)，其性質(zhì)既不同于其單一組成成分，也不同于其三維體材料。將這些晶體以堆疊方式組合，可用于設(shè)計(jì)此類異質(zhì)結(jié)構(gòu)的功能，并應(yīng)用于新型發(fā)光器件中，例如單光子發(fā)射器和可調(diào)諧發(fā)光二極管。 Graphene and layered materials have great potential in photonics and optoelectronics, where the combination of their optical and electronic properties can be fully exploited, and the absence of a bandgap in graphene can be beneficial. The linear dispersion of the Dirac electrons in graphene enables ultra-wide-band tunability as well as gate controllable third-harmonic enhancement over an ultra-broad bandwidth, paving the way for electrically tuneable broadband frequency converters for optical communications and signal processing. Saturable absorption is observed as a consequence of Pauli blocking and can be exploited for mode-locking of a variety of ultrafast and broadband lasers. Graphene integrated photonics is a platform for wafer scale manufacturing of modulators, detectors and switches for next generation datacom and telecom. These functions can be achieved with graphene layers placed on top of optical waveguides, acting as passive light-guides, thus simplifying the current technology. Heterostructures based on layers of atomic crystals have properties different from those of their individual constituents and of their three dimensional counterparts. The combinations of such crystals in stacks can be used to design the functionalities of such heterostructures, that can be exploited in novel light emitting devices, such as single photon emitters, and tuneable light emitting diodes.

糖質(zhì)，又稱為碳水化合物，是地球上含量最為豐富的生物大分子。盡管其生理功能至關(guān)重要，糖質(zhì)的結(jié)構(gòu)生物學(xué)研究卻顯著滯后于蛋白質(zhì)與核酸。前期對(duì)于人源葡萄糖轉(zhuǎn)運(yùn)蛋白 GLUT3 與 D-葡萄糖的1.5 ?分辨率晶體結(jié)構(gòu)清晰表明，該轉(zhuǎn)運(yùn)體能夠識(shí)別α與β兩種變旋異構(gòu)體。這一發(fā)現(xiàn)凸顯了高分辨率結(jié)構(gòu)在闡明糖質(zhì)分子的立體化學(xué)方面的重要作用。雖然冷凍電鏡已能夠解析膜蛋白胞外修飾的糖鏈結(jié)構(gòu)，但通常僅限于修飾位點(diǎn)附近的少數(shù)糖殘基，且難以獲得高分辨率結(jié)構(gòu)。近年來(lái)，我們一直致力于獲得完整糖鏈的高分辨率結(jié)構(gòu)，但進(jìn)展有限。通過(guò)建立名為“CryoSeek”的新范式，我們最近成功解析了多種具有高階結(jié)構(gòu)組裝特征的糖質(zhì)分子的高分辨率結(jié)構(gòu)。 Carbohydrates are the most abundant biomolecules on Earth. Despite their physiological importance, the structural biology of glycans has significantly lagged behind that of proteins and nucleic acids. The crystal structure of the human glucose transporter GLUT3 bound to D-glucose at 1.5 ? resolution clearly demonstrates that the transporter can recognize both α- and β-anomers. This finding underscores the power of high-resolution structures in elucidating the stereochemistry of sugars. While cryo-EM has enabled the structural resolution of glycan chains that modify the extracellular surface of membrane proteins, it has largely been limited to a small number of sugar residues near the modification site and at moderate resolutions. We have been striving to solve high-resolution structures of full glycan chains with little success until recently. By establishing a new paradigm called CryoSeek, we have successfully resolved the high-resolution structures of numerous glycans with higher-order structural assemblies.

自聚合物發(fā)現(xiàn)以來(lái)，科學(xué)家對(duì)其結(jié)構(gòu)始終存在爭(zhēng)論。在Hermann Staudinger提出大分子概念前，學(xué)界普遍認(rèn)為聚合物源于小顆粒或分子的膠體聚集。自1920年起，聚合物和大分子被認(rèn)為是通過(guò)共價(jià)鍵將單體在二維或三維空間連接構(gòu)成的材料。盡管大分子鏈間超分子相互作用的重要性不言而喻，但當(dāng)時(shí)難以設(shè)想基于小分子相互作用可構(gòu)建聚合物材料。超分子化學(xué)的突破性進(jìn)展表明，通過(guò)強(qiáng)方向性次級(jí)相互作用可實(shí)現(xiàn)小分子構(gòu)建聚合物材料——超分子聚合物領(lǐng)域由此誕生。通過(guò)控制分子片段間的超分子相互作用，設(shè)計(jì)具有響應(yīng)性與動(dòng)態(tài)功能的新型功能材料變得更為容易。其中，對(duì)分子時(shí)空位置的控制是獲得目標(biāo)功能的關(guān)鍵。本次講座將探討手性在時(shí)空維度中的典型案例及涌現(xiàn)機(jī)制，同時(shí)聚焦非共價(jià)合成中的分子相互作用，探討其在自旋過(guò)濾、生物材料及OLED等領(lǐng)域的應(yīng)用前景。 Since the discovery of the first polymers, scientists have debated their structures. Before Hermann Staudinger published the brilliant concept of macromolecules, it was generally assumed that the properties of polymers were based on the colloidal aggregation of small particles or molecules. Since 1920, polymers and macromolecules have been synonymous with each other; i.e. materials made by means of many covalent bonds that connect monomers in 2 or 3 dimensions. Although supramolecular interactions between macromolecular chains are clearly important, e.g. in nylons, it was unthinkable to imagine polymeric materials based on the interaction of small molecules. Breakthroughs in supramolecular chemistry have shown that polymer materials can be made by small molecules using strong directional secondary interactions; the field of supramolecular polymers was born. In a sense, we have come full circle [1]. By controlling the supramolecular interactions between molecular fragments, it became easier to design systems materials with unconventional responsive behavior and dynamic functionalities. In all cases, control over the position of the molecules in time and space is essential to achieve the required functionality. In our group we focus on the emergence of homochirality in time and space and some examples of this challenge will be discussed in the lecture. We use this to design supramolecular materials and chiral systems with highly ordered morphologies that change their properties on the action of light, pressure, temperature, or the addition of chemicals. On the other hand, applications in spin filtering, biomaterials and OLEDs will be discussed with a continues focus on the molecular interactions using non-covalent synthesis [2].

基因打靶（gene targeting）的誕生，標(biāo)志著分子遺傳學(xué)從描述性研究進(jìn)入可定向改造基因功能的時(shí)代。上世紀(jì)八十年代，馬里奧·卡佩奇教授通過(guò)在哺乳動(dòng)物胚胎干細(xì)胞中實(shí)現(xiàn)同源重組，首次建立了在基因組特定位點(diǎn)進(jìn)行精準(zhǔn)修飾的技術(shù)。這一突破使科學(xué)家能夠“敲除”或“敲入”特定基因，從而系統(tǒng)地研究其在發(fā)育、生理與疾病中的功能。該方法孕育了“敲除小鼠”模型，為人類遺傳病、腫瘤和神經(jīng)系統(tǒng)疾病研究奠定了基礎(chǔ)，并推動(dòng)了現(xiàn)代基因治療與精準(zhǔn)醫(yī)學(xué)的發(fā)展。本報(bào)告將回顧基因打靶技術(shù)從概念到實(shí)現(xiàn)的科學(xué)歷程，探討其對(duì)生命科學(xué)與醫(yī)學(xué)的深遠(yuǎn)影響。 Gene targeting marked the transition of molecular genetics from largely descriptive studies to an era of targeted engineering of gene function. In the 1980s, Professor Mario R. Capecchi achieved homologous recombination in mammalian embryonic stem cells, thereby establishing the first technology for precise modification at defined genomic loci. This breakthrough enabled scientists to knock out or knock in specific genes and to systematically interrogate their roles in development, physiology, and disease. The method gave rise to knockout mouse models, laid the foundation for research on human genetic disorders, cancer, and neurological diseases, and propelled the development of modern gene therapy and precision medicine. This lecture will retrace the scientific journey from concept to realization and explore the profound impact of gene targeting on the life sciences and medicine. 為了傳播感染，人類免疫缺陷病毒（HIV）需形成具有包膜的球形顆粒，并通過(guò)質(zhì)膜出芽釋放。我們研究發(fā)現(xiàn)，HIV-1及其他逆轉(zhuǎn)錄病毒通過(guò)劫持宿主的內(nèi)體分選轉(zhuǎn)運(yùn)（ESCRT）通路的活性實(shí)現(xiàn)出芽。我們與合作團(tuán)隊(duì)進(jìn)一步研究了ESCRT通路在HIV出芽、細(xì)胞分裂及其他關(guān)鍵細(xì)胞功能中的作用，并解析了十余種不同ESCRT因子及復(fù)合體的三維結(jié)構(gòu)。這些研究揭示了ESCRT組分如何組裝、相互作用并識(shí)別病毒及泛素化蛋白，ESCRT-III亞基如何通過(guò)構(gòu)象變化形成能夠重塑細(xì)胞膜的纖絲狀結(jié)構(gòu)，以及ATP水解所釋放的能量如何驅(qū)動(dòng)膜重塑。 To spread infections, the human immunodeficiency virus (HIV) must form enveloped spherical particles that bud through the plasma membrane. We have demonstrated that HIV-1 and other retroviruses bud from cells by usurping the activity of the host Endosomal Sorting Pathway Required for Transport (ESCRT) pathway. We and our collaborators have also explored the functions of the ESCRT pathway in HIV budding, cell division and other cellular functions, and determined the three-dimensional structures of more than a dozen different ESCRT factors and complexes. This work has helped reveal how ESCRT components assemble, interact, and recognize viral and ubiquitylated proteins, how ESCRT-III subunits can change conformations and form filaments that remodel membranes, and how the energy of ATP hydrolysis is used to power membrane remodeling.