Heat transfer in microchannels

The objective of this research was to develop an analytical solution to the heat transfer problem in microchannels with slip-flow--a heat transfer problem for gases at low pressures or in extremely small geometries, and to verify this solution experimentally. In this investigation, an analytical expression for the velocity distribution with slip-flow was obtained which involved the Knudsen (Kn) number in an infinite series form. The result showed that the velocity always increased as the Knudsen number was increased. The Knudsen number for extremely small channels may become large enough to affect significantly the velocity distribution and consequently affect the heat transfer properties. A mathematical model of temperature distribution was established by combining the energy and momentum equations. A series solution was obtained. Also, expressions for the local and overall Nusselt numbers were derived in terms of the Knudsen number and Graetz number. A new technique for evaluation of eigenvalues for the solution of the heat transfer problem in microchannels was developed. This method was based on the construction of a matrix. The computational results showed that the method was effective. The local values and average Nusselt number were found for Kn from 0.005 to 0.3 with aspect ratio $a=1,\ 2/3,\ 1/2,\ 1/4$ and 1/8. Experiments for helium through a microchannel with dimensions of 117 $\mu$m x 24 $\mu$m x 63.5 mm and a microtube with inside diameter of 52 $\mu$m were conducted

When Image Denoising Meets High-Level Vision Tasks: A Deep Learning Approach

Conventionally, image denoising and high-level vision tasks are handled separately in computer vision. In this paper, we cope with the two jointly and explore the mutual influence between them. First we propose a convolutional neural network for image denoising which achieves the state-of-the-art performance. Second we propose a deep neural network solution that cascades two modules for image denoising and various high-level tasks, respectively, and use the joint loss for updating only the denoising network via back-propagation. We demonstrate that on one hand, the proposed denoiser has the generality to overcome the performance degradation of different high-level vision tasks. On the other hand, with the guidance of high-level vision information, the denoising network can generate more visually appealing results. To the best of our knowledge, this is the first work investigating the benefit of exploiting image semantics simultaneously for image denoising and high-level vision tasks via deep learning. The code is available online https://github.com/Ding-Liu/DeepDenoising.Comment: the 27th International Joint Conference on Artificial Intelligence (2018

乡村建设思想的历史起点

在近代中国思潮的起伏波动中，重商主义的倡导与中国传统的重农思想的冲突在所不免，由此引发了一场持续数十年的“工商立国”与“农业立国”之争。自1901年初《自强说》发表至1911年清朝覆亡的10年间，见诸报刊的讨论文字日渐增多，其观点则大致可分为工商为本论，农工商并重论，农业为本论三大类。1920年《农业立国意见书》的发表，标志着“农业立国论”将在未来的历史选择中开始拥有了独特的时代意义和价值。从某种意义而言，它形成了其后乡村建设思想的历史起点

Research on Innovating English Practical Teaching Approach to Enhance the Employability of College Students

The connotation of college students’ employability is very rich, including both hard power of professional knowledge and occupation ability, and soft power of management, innovation, cooperation, learning and expression analysis etc. How to cultivate and enhance students’ employability through daily teaching process is always one of the key reforms in colleges and universities. Based on the English practical teaching reform, this paper explores and researches suggestive approach to improve the employability of college students

Reflection on Challenges and Countermeasure of Entrepreneurship Education in China

With the rapid pace of globalization, uncertainty, and discontinuous knowledge-based society, for a country, innovation and entrepreneurship have become the main competence. After the World War Ⅱ, small and medium sized enterprises have promoted economic productivity and offered new job opportunities. Based on this, Entrepreneurship education has become a rapid new field in the universities. Entrepreneurship education is one of the basic ways to solve the employment problem of university students. At present, university enterprise education in China has just started, facing many problems. This paper attempts to make a theoretic reflection on problems of entrepreneurship education in China and make suggestive countermeasure