【Editor's Note】
May 27, 2023 is the 118th anniversary of Fudan University. "The celebration of various activities is centered on the promotion of scientific research." Since 1954, on the eve of the school anniversary, then president Chen Wangdao put forward this idea, holding scientific reports during the school celebration has become one of the important academic traditions in Fudan.
Continuing the academic tradition, the string song is endless. From May 9th, more than 50 famous teachers from various disciplines of culture, social science, engineering and medicine will give academic speeches one after another.
At the new engineering session "Continue to Promote Integration and Innovation and Create New Momentum for the Development of New Engineering" to celebrate the 118th anniversary of the founding of the university, 7 scientists from Fudan shared the cutting-edge progress in their fields, opening a window of future science and technology for the audience.
Liu Ming, director of the National Key Laboratory of Integrated Chips and Systems, dean of the Institute of Chip and System Frontier Technology, and academician of the Chinese Academy of Sciences, Zhan Yiqiang, academic leader of the National Key Laboratory of Photovoltaic Science and Technology, deputy dean and professor of the School of Information Science and Engineering, Yan Bo, professor of the School of Computer Science and Technology, Zhou Peng, deputy director of the new generation of integrated circuit technology integration platform, deputy dean and professor of the School of Microelectronics, and He Dean, deputy director of the Institute of Biomedical Engineering Technology and professor of the School of Information Science and Engineering, Xu Feng, director of the Key Laboratory of Electromagnetic Wave Information Science of the Ministry of Education, deputy dean and professor of the School of Information Science and Engineering, and Fang Hongbin, a young researcher of the Institute of Engineering and Applied Technology, gave reports successively.
The innovative development path of integrated circuits
"This year marks the 76th anniversary of the birth of the transistor, and I want to review with you how transistors and integrated circuits have evolved and how they have changed the way each of us live." At the beginning of the report meeting, Liu Ming briefly outlined the development process of integrated circuits.
Liu Ming All pictures in this article are courtesy of Fudan University
"The invention of the transistor is not an isolated event." Historically, countless scholars have contributed to the field of integrated circuits, and transistors were developed by predecessors based on a deep understanding of solid-state physics and driven by market demand. Liu Ming concluded: "Devices and circuit architectures with different principles and functions enable integrated circuits to be widely used in different fields, and researchers' breakthroughs in devices and circuit architectures will also allow integrated circuits to have new application scenarios." ”
Liu Ming introduced that increasing integration, improving performance and reducing power consumption are the core goals of the development of integrated circuit technology, and for a long time, the continuous scaling of transistor size has driven the rapid progress of integrated circuit technology. Materials, device structures, lithography, packaging, and even EDA tools are all evolving in the process of integrated circuit size miniaturization.
In order to promote the further scaling of transistor size, the manufacturing process and equipment of integrated circuits are becoming more and more complex, Liu Ming took EUV lithography machine as an example, introduced the diversified innovation of lithography technology from the light source, lens material and structure, pattern transmission mode, pointed out that EUV lithography machine can be called the most complex and accurate machine made by human beings so far, and it is also the product of global industrial cooperation.
At the same time, advanced process chips face the constraint of lithography "area wall", and the single wafer (die) area has approached the limit of the graphic projection capability of the lithography machine. In response to such challenges, Liu Ming proposed that the integrated circuit industry is entering a new stage of coordinated development of system, design, manufacturing and packaging. Integrated chip technology - die-level semiconductor integration technology can decompose complex chips into pellets, and use silicon precision manufacturing technology to integrate several dies to achieve complex system integration and application, break through the limitation of "area wall", and realize the improvement of chip performance and function expansion.
Sustainable development requires new solar cells that are more efficient and stable
Zhan Yiqiang pointed out in the report entitled "Research on Flexible, Efficient and Stable Perovskite Solar Cells" that at present, global energy and environmental problems are prominent, and the overall development of perovskite cells can effectively improve the supply capacity of solar photovoltaic products and technologies, promote sustainable development, and accelerate the realization of carbon peak and carbon neutrality.
Zhan Yiqiang
Solar energy is an ideal clean energy, and the use of semiconductor photovoltaic effect is an important way for human beings to use solar energy efficiently. Zhan Yiqiang introduced that perovskite new photovoltaic technology is one of the key research directions of the National Key Laboratory of Photovoltaic Science and Technology of Fudan University, and has obtained high efficiency comparable to monocrystalline silicon technology, with unique advantages such as low cost, low energy consumption, compatibility with large area, and flexibility.
Facing the major needs of the country, the team strives to solve major scientific problems in advanced solar cell technology, focuses on key tasks such as the practical frontier technology of low-cost and high-efficiency perovskite cells, and creates a source of photovoltaic technology innovation.
Through more than ten years of systematic research, the team used the covalent crosslinking strategy to initially solve the core problem of perovskite intrinsic stability, and combined with various means such as surface interface modification and stress regulation to improve the working life of the device. Related research has developed a low-temperature preparation process suitable for flexible substrates, which uses downconversion luminescent materials to broaden the light absorption range of flexible perovskite, and can prepare more efficient flexible perovskite photovoltaic devices. Facing the future, flexible perovskite devices are also likely to be widely used in aerospace, building photovoltaic integration, transportation, wearable portable devices and other fields.
The development of AIGC large models is the general trend in the future
At present, AIGC (or "generative artificial intelligence") is subverting scientific research in various fields and also has an impact on human society. Yan Bo introduced in the report entitled "AIGC New Engine and Its Multidisciplinary Cross-integration Application" that AIGC includes three major elements: computing power, data and algorithms, and its technology has evolved into three cutting-edge capabilities of twin, editing and creation. The AIGC+X paradigm enables new methods for scientific research, the discovery of new materials, and the generation of new data.
Yan Bo
"Quantitative change has triggered a qualitative change in AIGC's generation ability, such as the recent hot language model ChatGPT, which allows us to see the result of a qualitative change." Yan Bo said that at present, the AIGC model has the potential to be highlighted, which can achieve high-fidelity 3D modeling, real-time synthesis of talking portraits, and can also synthesize creative content based on text to generate high-resolution videos.
With the development of society, the industry has put forward new needs in the fields of smart security, smart medical care, and smart terminals, in this regard, AIGC can better solve the problems of media adaptation editors not being real, remote small objects not being accurate, and low-quality and low-resolution problems that cannot be seen clearly.
AIGC's strong editing capabilities are also playing an important role in the real world. The "fully enriched" surveillance video enrichment system developed by his laboratory realizes the rapid positioning and identification of conditional semantics, achieves the purpose of rapid solving of cases, and reduces the search time by 99%. At present, this surveillance video full enrichment technology and system has been successfully applied in the investigation of Shenzhen public security.
AIGC's twin ability is also cleverly applied to the restoration of historical materials in the Fudan University History Museum, which can reproduce important historical image materials carrying Fudan's memories in high definition.
In the field of AI+ medical treatment, the laboratory conducts research on AIGC+ medical applications and develops the core algorithm and hardware system of "endoscopic smart eye". The results have benefited more than 80,000 patients in the past four years.
Yan Bo finally concluded that the development of AIGC big model is the general trend in the future, which will strongly support the research of AI+ science and bring a new research paradigm.
The two-dimensional semiconductor industry integrated with silicon is a new blue ocean
Integrated circuits play a fundamental supporting role in the development of China's modern industry and are an important part of achieving high-level scientific and technological self-reliance. Transistors are the underlying technology related to the future of mankind, and crystalline silicon helps transistors achieve the "incremental" miracle of integrated circuits.
In recent years, the problems and challenges in the field of integrated circuits have become more and more obvious, the most important are the process problems caused by miniaturization, the energy consumption problems caused by high energy density and the speed mismatch caused by storage walls. Limited by the three physical principles of size miniaturization, power consumption and energy efficiency, and storage walls, the development of integrated circuit performance has gradually slowed down.
ZHOU Peng
Only innovation can break through the bottleneck, and the field of integrated circuits urgently needs breakthroughs in new materials, new structures and new devices. Zhou Peng's team set their sights on two-dimensional materials with richer physical properties and more diversified properties to build new devices and find solutions to the current problems of integrated density and energy consumption for silicon.
"Thanks to its unique and excellent performance, two-dimensional semiconductors are expected to overcome the bottleneck of traditional technologies and alleviate the energy consumption challenges and storage dilemma of silicon-based integrated circuit development." Zhou Peng introduced. In recent years, Zhou Peng and his team have achieved a series of research results such as dual-surface channel transistors (TSCFET), ultra-thin multi-channel fence-fence transistors (MBCFET), silicon-based two-dimensional heterogeneous integrated stacked transistors (CFET), and two-dimensional PN junction flash memory (Flash).
"My report today is to prove that two-dimensional semiconductors are feasible." Zhou Peng introduced that two-dimensional semiconductors have unique electrical, thermal, chemical and optical properties, which are expected to achieve final gate length scaling, which can be used to build compact back-end CMOS circuits (CFET), laboratory-based ultra-large size 2D transistors have shown good performance, and a way to produce 2D-FETs on an industrial scale is also being developed.
Zhou Peng believes that the two-dimensional semiconductor industry integrated with silicon is a new blue ocean, which requires further innovation-driven and continuous core technology research and development.
Challenging the "forbidden zone": ultrasound evaluation and regulation of the skeletal system
More than two decades ago, bones were a "no-go zone" for ultrasound diagnosis. His team challenged the "no-go zone" and made great progress in bone ultrasound research. This time, he brought a report entitled "Ultrasound Evaluation and Regulation of the Skeletal System".
Osteoporosis is the second largest disease affecting human health, and there are more than 100 million osteoporosis patients in China. It can be said that the research of bone ultrasound is oriented to people's life and health and major national strategic needs.
Osteoporosis in adults is diagnosed mainly by X-ray, CT, and dual-energy X-ray. "These methods can reflect the 'quantity' of bone, i.e. bone density, but they do not reflect the 'quality' of bone, such as bone elasticity." He pointed out.
Over the years, ultrasound has been valued and clinically applied because of its many advantages. However, most of the existing bone ultrasound imagers use ultrasonic transmission method, and the measurement site is limited, usually only the calcaneus part can be measured; The imaging spatial resolution is low and can only roughly display the morphological and contour information inside the bone.
He was in peace
In the face of many challenges, his team proposed a honeycomb cancellous bone ultrasonic scattering theoretical model, constructed a theoretical model of ultrasonic propagation in mucus-filled, multilayer tubular long bone, optimized the inverse problem solving algorithm based on meta-learning, and developed a new bone ultrasound diagnostic instrument based on ultrasonic backscattering.
At present, this bone ultrasound diagnostic instrument has been applied to the Earth Star II experimental head low bed rest experiment. It provides an important theoretical basis and a large number of valuable experimental data for the study of bone loss in microgravity environment and for the bone loss confrontation of astronauts on the Chinese space station.
A revolution in radar technology: synthetic aperture radar
A week ago, the Shanghai Science and Technology Award Conference came with good news, and Xu Feng's team won the first prize of Shanghai Natural Science Award. Standing on the podium of Xianghuitang this time, he brought a report entitled "Microwave Vision and Radar Intelligent Target Recognition".
Xu Feng
The most traditional radar, invented during World War II, is equipped with a circular display interface, on which detected targets appear as cursors. Xu Feng's team is studying synthetic aperture radar (SAR), which can be installed on flight platforms such as satellites or aircraft to image the ground all day and all-weather, realizing the leap from one-dimensional ranging to two-dimensional high-resolution imaging, which is a revolution in radar technology.
After more than 40 years of independent research and development, Mainland China has launched dozens of radar satellites, but it is still facing the application bottleneck of radar image interpretation, which needs to be broken through. "Radar satellites can obtain massive amounts of data every day, and it is very inefficient to train professionals to manually interpret it. The mainland urgently needs to carry out basic research on automatic interpretation of SAR images. Xu Feng said.
Microwave vision is a new concept proposed by Academician Jin Yaqiu, that is, the development of physics-inspired artificial intelligence technology dedicated to automatic interpretation of microwave domain radar images. Xu Feng introduced the differences between microwave vision and traditional optical vision in terms of working principle, image properties, cognitive mechanism and so on. If optical vision is based on the innate vision neural network of optical excitation and the biomimetic vision trained by acquired big data, then microwave vision is interpretable physical vision based on electromagnetic physics mechanism and can adapt to sparse data.
In addition to discussing the physical, intelligent and cognitive foundations of microwave vision, and proposing a variety of intelligent target recognition algorithms, Xu Feng's team also designed a set of UAV-borne radar imaging algorithms and systems for the integrated application of detection and imaging recognition. In the video played at the report meeting, the drone slowly rose on the light grass, and high-resolution SAR imaging was done on the headquarters and south of the Handan campus, realizing high-resolution imaging without assisted positioning, and the team is currently developing a microwave vision principle prototype for on-board and on-board intelligent processing, and further pushing the research results to the actual system.
After the advent of various large models, Xu Feng's team did some tests on them and found that it was difficult to directly apply radar images with strong physical properties, indicating that it did not learn systematic physics knowledge, so he believed that Science for AI represented by physical intelligence had a lot of room for development. Faced with the question of "does ChatGPT mean the arrival of the singularity", Xu Feng made his own response at the end of the report, "Whether the singularity comes or not, we believe in science!" ”
Build the robots of the future and take inspiration from nature
Where will robots go in the future? Animals and origami provide endless inspiration for scientists.
"The development of robots has been taking inspiration from nature, such as service robotic arms and quadruped robotic dogs are common cases in our lives." In Fang Hongbin's view, bionics is an important force to promote the progress of robot technology.
The design, modeling and control of bionic mobile robots are both new hotspots and new challenges. In the face of narrow and restricted environments, such as survivor search and rescue in disaster ruins, industrial pipeline inspection and cleaning, human gastrointestinal detection and treatment, battlefield information concealment reconnaissance and other tasks, traditional wheeled and legged robots are powerless, which urgently requires further learning from animals and proposing a new robot structure design.
Fang Hongbin
How to learn from animals? "Legless animals have the ability to move well in unstructured environments such as restricted and narrow, such as earthworms, which have the ability to move both above ground and in underground pipes," Fang said. "Learning the morphological characteristics and movement mechanism of legless animals and developing bionic legless mobile robots is an important direction for the development of robots in the future."
In recent years, the Bionic Structure and Robotics Laboratory of the Institute of Intelligent Robotics of Fudan University has made many innovative achievements in the field of worm-like mobile robots. Fang Hongbin's "peristaltic + swimming", "peristalsis + swinging", "peristalsis + rolling" and other multi-modal mobile robots imitating worms can move efficiently in complex environments including pipelines, water areas and gravel ground. Fang Hongbin also innovatively introduced the idea of "folding" into robot development, innovated the traditional "three-dimensional design-three-dimensional processing-final assembly" robot preparation process to "two-dimensional crease processing-folding", and designed a variety of origami imitation worm mobile robots, which constitute an important direction for future robot development.
Fang Hongbin believes that bionic robots and origami robots research opportunities and challenges coexist, the future robots will show more rigid-flex coupling features and reconfigurable features, robot performance will also continue to move forward in the direction of multimodal motion, high performance, miniaturization and intelligence.