摘要：纳米材料可有效改善水泥基的力学性能和耐久性,为探索纳米SiO2、Fe2O3对混凝土材料的增强机理,研制力学性能更优的混凝土,制备了0%～2.0%掺量范围内单掺纳米SiO2、纳米Fe2O3、复掺纳米SiO2和纳米Fe2O3的混凝土试件,对养护龄期为7 d及28 d的混凝土力学性能开展试验研究,结果表明:纳米材料总掺量为1.5%且纳米SiO2掺量为1.0%、纳米Fe2O3掺量为0.5%时改性混凝土的力学性能达到最优,该复掺比例改性混凝土比普通混凝土及同掺量的单掺改性混凝土具有更优异的力学性能。采用冷场发射扫描电镜对纳米改性混凝土内部微观形貌进行观察,并借助能量分散谱仪分析纳米改性混凝土的化学成分,结果表明掺入的纳米SiO2及纳米Fe2O3会发生晶核作用并与Ca(OH)2晶粒发生化学反应,在混凝土内部分别生成珊瑚状、球状水化产物C-S-H凝胶及C-F-H凝胶,晶核的高活性吸附凝胶在其表面聚集,减少Ca(OH)2晶粒的数量,并互补填充形成密实的水化产物,使混凝土结构更加紧实致密。研究成果可为高性能混凝土的研发提供参考。
摘要：This paper presents an overview of the theories and computer implementation aspects of phase field models (PFM) of fracture. The advantage of PFM over discontinuous approaches to fracture is that PFM can elegantly simulate complicated fracture processes including fracture initiation, propagation, coalescence, and branching by using only a scalar field, the phase field. In addition, fracture is a natural outcome of the simulation and obtained through the solution of an additional differential equation related to the phase field. No extra fracture criteria are needed and an explicit representation of a crack surface as well as complex track crack procedures are avoided in PFM for fracture, which in turn dramatically facilitates the implementation. The PFM is thermodynamically consistent and can be easily extended to multi-physics problem by 'changing' the energy functional accordingly. Besides an overview of different PFMs, we also present comparative numerical benchmark examples to show the capability of PFMs.
摘要：Digital liquid sample handling is an enabling tool for cutting-edge lifesciences research. Similar to Field Programmable Gate Arrays (FPGA) in Integrated Circuits, we present here an active-matrix thin-film electronicsbased digital microfluidics system, which will be henceforth referred to as Field Programmable Droplets Arrays (FPDA). The system contains 256 × 256 pixels in an active area of 10.65 cm2, which is capable of manipulating thousands of individually addressable liquid droplets simultaneously. By leveraging a customised TFT-based circuit design solution, it becomes possible to programmatically manipulate droplets at the pixel level. The minimum achievable droplet volume is around 0.5 nl, which is two orders of magnitude smaller than the state-of-the-art reported1. The movement of droplets can be either pre-programmed or controlled in real-time. The FPDA system shows great potential of the ubiquitous thin-film electronics technology in digital liquid handling. These efforts will make it possible to create a true programmable lab-on-a-chip device to enable great advances in life science research.
摘要：In this work, a design of large-bandwidth high-gain low-noise transimpedance amplifier (TIA) for scanning tunneling microscope (STM) is proposed. The simulations show that the proposed TIA has the bandwidth higher than 200 kHz, two orders of magnitude higher than those of conventional commercial TIAs for STM. At low frequencies, the noises of the proposed TIA are almost the same as the conventional commercial ones with the same transimpedance gain. At high frequencies, its calculated input equivalent noise voltage power spectral density (PSD) is 40 (nV)2/Hz and its input equivalent noise current PSD is 3.2 (fA)2/Hz at 10 kHz. The corresponding values are 23 (nV)2/Hz and 88 (fA)2/Hz at 100 kHz. The STM with the proposed TIA can meet the needs of fast high-quality STM imaging measurements and fast high-energy-resolution scanning tunneling spectra measurements for the low-conducting materials, such as complex organic systems and wide bandgap semiconductors.
摘要：An ultra-low-noise large-bandwidth transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA connected with the tip-sample component in CryoSTM is called as CryoSTM-TIA. Its transimpedance gain is as high as 1 GΩ, and its bandwidth is over 300 kHz, but its equivalent input noise current power spectral density is less than 4 (fA)2/Hz at 100 kHz. The low inherent noise for the CryoSTM-TIA is due to its special design: (1) its pre-amplifier is made of a pair of low-noise cryogenic high electron mobility transistors (HEMTs); (2) the noise generated by one HEMT is eliminated by a large capacitor; (3) the capacitance of the cable connected the gate of the other HEMT to the tip is minimized; (4) thermal noise sources, such as the feedback resistor, are placed in the cryogenic zone. The dc output voltage drift of the CryoSTM-TIA is very low, as 5 μV/°C. The apparatus can be used for measuring the scanning tunneling differential conductance spectra, especially the scanning tunneling shot noise spectra (STSNS) of quantum systems, even if the shot noise is very low. It provides a universal tool to study various novel quantum states by measuring STSNS, such as detecting the Majorana bound states.
摘要：Cultural confidence is one of the important factors to promote the inheritance and development of excellent national culture. Maonan traditional craft contains excellent national culture, cultural customs and so on, which is a part of carrying forward China's traditional culture confidence. From the perspective of cultural confidence, this paper analyzes the characteristics and advantages of the current Maonan traditional crafts and puts forward suggestions to promote the innovative development of Maonan traditional crafts, which can better promote the inheritance and development of Maonan traditional crafts.
摘要：Driven by the rapid development of omnimedia, the Internet, movies, television, etc. have gradually blend in people’s daily lives, and cartoons are also deeply loved by children. Colleges and universities are an important base for cultivating animation talents, in the process of carrying out animation teaching, due to the short setting up time and other reasons, it is necessary to continuously improve the teaching system of animation professional courses, and comprehensively analyze the current problems in teaching, so as to provide more help for students’ learning and avoid being affected by a variety of factors that lead to the inability to effectively improve teaching efficiency. In the language environment of omnimedia, it is necessary to actively improve the efficiency of animation teaching, optimize the teaching system according to the actual situation, and implement the teaching of all links to maximize the role of curriculum system reform. Based on this, this paper mainly analyzes the importance and necessity of animation curriculum reform in the language environment of omnimedia.
摘要：Traditional dwellings with high regional artistic expression, is an important carrier of China's national culture, regional characteristics, ethnic customs. The wooden architecture of the Dong Nationality 's residential houses originated from the southern stilt-style architecture. Its unique construction technology is a treasure of national culture. Studying the aesthetic implication of Dong residential buildings will help people understand Dong culture more deeply. From the perspective of artistic aesthetics, this paper makes a detailed study of the dwellings of Dong people from five aspects: the environmental beauty of man-nature harmony, the beauty of building materials, the beauty of structure, the beauty of architectural skills and the beauty of culture. Hope to help readers understand the spiritual core of Dong culture, to better protect the Dong residential buildings wooden.
摘要：In the past 30 years, the development of brownland into green land has become an important way for the sustainable development and management of urban land. Fully understanding the various application scenarios and values of this approach is helpful to explore its efforts in providing ecosystem services and meet the development needs of different types of cities. This paper reviews the practice and literature of brownfield redevelopment from the perspective of landscape architecture, and obtains the process of its theoretical development and its understanding deepening. Through sorting out the relevant discipline literature, the seven main green space types and their potential broad benefits are summarized, and we realize that the brownfield itself has many values that cannot be ignored in the development process. On this basis, it proposes that there is a new cognition of the relationship between brownfield and green space.
摘要：In the post-epidemic era, great turbulence has taken place in the field of human life, especially the travel rate of people has been greatly reduced, but the requirements for urban public space required for travel are constantly improving.As the main social life space carrier of street space requires carrying more functions to meet the requirements of the outbreak era.Through literature search and social investigation, the optimization design strategy is proposed for the problems of weak slow traffic use right, monotonous space function, lack of commercial management, and random public facilities of urban streets. Then, through the legend analysis, the optimization effect of street space in four levels of environmental comfort, functional diversification, management order and facilities refine#2;ment can be achieved to improve the residents' street life experience and return to the public space essence of "people-oriented" street.
摘要：With the change in media technology, the pattern of time and space is constantly broken, and the development of media tends to be more and more spatial and temporal freedom. On the social level, the social range of the general public is expanding, and the social distance is shrinking based on the expansion. However, people's senses have also changed, from balance to breaking balance to the constant pursuit of balance. In this paper, we will discuss the body logic of social networks and the future development trend of social networks from the perspective of senses based on the change of senses in the media.
摘要：In order to explore the cultural connotation and artistic characteristics of Tang Dynasty ceramic decorative patterns, integrate traditional ethnic decorative patterns with modern design, and promote the inheritance and development of excellent traditional culture, this paper first understands the decorative patterns of Tang Dynasty ceramics by reading books and consulting materials, collects representative ceramic utensils of the Tang Dynasty, and extracts the decorative patterns on these cultural relics, analyzes the inner meaning of the patterns through semiotics, and understands their aesthetic characteristics. The use of shape grammar, complexity into simplicity, decomposition and reconstruction of the extracted pattern for innovative design, into the modern aesthetic concept, according to its semantic and visual characteristics into the modern product design and decoration. The Tang Dynasty is a representative period of China's culture, and the combination of Tang Dynasty patterns and modern design is conducive to inheriting the excellent culture of the Tang Dynasty, while increasing the cultural value of modern design and enhancing product competitiveness.