Newsletter No. 385

No. 385, 19.10.2011 7 校 園 消 息 CAMPUS NEWS 入學資訊日參加人數創新高 • Orientation Day Draws Record-Breaking Number of Visitors 中 大在10月8和9日於 校園舉辦本科入學資 訊日，吸引了大批中學生、家 長和教師參加。兩天的總參 觀人數約有八萬九千人，創歷 屆新高。 中大校長沈祖堯教授在10月 8日早上與在學中大生對話， 分享中大豐盛及多元的校園 生活，包括四年制課程、書院 制度、通識教育、交流機會和 I．CARE 博群計劃，為資訊 日揭開序幕。 當天三場為新高中學生而設 的講座全部滿座。講座中， 侯傑泰副校長介紹了明年開 始推行的四年課程新學制，入學及學生資助處處長周陳文 琬則講述新學制下的收生安排。此外，還有多場分別以粵 語、英語及普通話進行的入學講座及有問必答諮詢會，介 紹中大的入學資料。 資訊日節目除了入學講座外，八所學院分別安排了豐富活 動以介紹其學系及課程，包括資料展覽、開放實驗室及有 關設施，以及各類示範活動。此外，九所書院也開放宿舍 及學生設施，或舉行講座、設立展覽攤位等，向來賓介紹 書院特色。 C UHK held its Orientation Day for Undergraduate Admissions on 8 and 9 October, attracting some 89,000 visitors, many of them secondary school teachers, students and their parents, to our campus. A sharing session was arranged on the morning of 8 October to kick off the event. In the sharing session Prof. Joseph J.Y. Sung, CUHK Vice-Chancellor, and some CUHK students shared what they felt about the various facets of university life on our campus, including the four- year curriculum, the college system, general education, exchange programmes and the I • CARE programme. The three admission talks held that day for applicants with the Hong Kong Diploma of Secondary Education qualifications drew a full house. In the talks, Prof. Hau Kit-tai, Pro-Vice-Chancellor, introduced the audience to the new four-year undergraduate curriculum, while Mrs. Chow Chan Man-yuen Grace, Director of Admissions and Financial Aid, explained the admission arrangements when the new curriculum is implemented next year. There were other admission talks and Q&A sessions delivered in Cantonese, English and Putonghua to familiarize visitors with the University’s admission requirements. In addition to admission talks, exhibitions, demonstrations, visits to laboratories and other facilities were organized by the eight Faculties. The nine Colleges of the University organized open houses, information sessions and set up booths to give the visitors a better understanding of the characteristics of CUHK Colleges. S ome of you may remember that at the beginning of A Beautiful Mind , a film about the legendary mathematician John Nash, the male protagonist positions a drinking glass against the sun so that the refracted light falls on the necktie of his schoolmate. The budding mathematician muses, ‘There could be a mathematical explanation for how bad your tie is.’ Innocent as this quip may seem, Prof. Wei Juncheng of the Department of Mathematics at CUHK would not hesitate to add that natural phenomena can also be explained in mathematical terms and mathematics is the tool for everything ranging from physics, life to finance. The refraction of light in the above example can be explained by the Maxwell Equations. The spots on deer and leopards, and the stripes on clownfish and zebras are all translatable into a set of partial differential equations for the Reaction-Diffusion Systems. Partial differential equations come in handy because a differential operator is needed to express the relationship of a variable with time and space. Let’s look at the animals. Whether we find spots or stripes on their bodies is a result of the distribution and concentration of the molecules of a pigment in the medium of another pigment and the interaction between their molecules. Reaction-diffusion equations can explain the interaction between two media, in different proportions, and how one medium is distributed or aggregates in another medium. They can be used to explain the spots or the stripes found in animals, or even the moles and spots on human skin that may change colour or migrate with time. When the proportion of two media is more balanced, the mathematical solution of the reaction-diffusion equation would just result in stripes. When the proportion is more extreme, the result would be spots. Thus, both stripes and spots can be described with a pair of reaction- diffusion equations. In other words, the pigments of orange and black on a clownfish are balanced in proportion and result in the stripes we see on it. If the orange pigment dominates, the equation would tell us that the black pigment would aggregate in the form of spots and we would have a clownfish with leopard- like spots. However, simple physical phenomena can be easily explained by relatively simple mathematical equations. With the increasing complexity of other phenomena, more sophisticated mathematical methods are required. Prof. Wei Juncheng is one of the leading figures in the field of partial differential equations, particularly in the analysis of concentration phenomena in nonlinear elliptic equations and systems. The de Giorgi Conjecture is one of the most famous conjectures in pure mathematics, proposed by the Italian mathematician Ennio de Giorgi in 1978. It concerns the structure of certain nonlinear equations and had puzzled mathematicians around the world. Up to 2006, the conjecture was shown to be true in the second to the eighth dimensions. Thus researchers generally held that the conjecture would apply in any number of dimensions. Through an ingenious mathematical method, Professor Wei and his team were able to find a counter example in the ninth dimension and show that it could not have applied in any dimension higher than the eighth. Professor Wei’s solving of the de Giorgi Conjecture also helped solve the complex reaction-diffusion equations. He found that with the increase of the diffusion parameter in the equations, the spots would become unstable and might split into two or even more to form complex patterns. The seemingly random and haphazard phenomena in nature actually obey rules and follow orderly paths developed with the intelligence of the human mind. The study of mathematics has made us see through a natural phenomenon. It has also demonstrated its generality of application and structural beauty. The reaction-diffusion equations are not only applicable to animal patterns but also to the physical structure of superconductors, to an understanding of the spread of an epidemic, or may even tell us how cells take in nutrients. Researching into the mathematical structure of differential equations can take one outside mathematics itself into different fields of knowledge. This is what fascinates mathematicians like Prof. Wei Juncheng.