document

A study on siting of emergency shelters for dam failure floods considering population distribution and weather effects

Jiao, Yutie (author), Li, Zongkun (author), Ge, Wei (author), Jing, Laihong (author), Wu, Meimei (author), Wang, Te (author), Sun, Heqiang (author), Wang, Jianyou (author), Zhang, Xiangyang (author), van Gelder, P.H.A.J.M. (author)

In recent years, dam failures have occurred frequently because of extreme weather, posing a significant threat to downstream residents. The establishment of emergency shelters is crucial for reducing casualties. The selection of suitable shelters depends on key information such as the number and distribution of affected people, and the...

journal article 2024

document

Deep reinforcement learning control approach to mitigating actuator attacks

Wu, C. (author), Pan, W. (author), Staa, Rick (author), Liu, Jianxing (author), Sun, Guanghui (author), Wu, Ligang (author)

This paper investigates the deep reinforcement learning based secure control problem for cyber–physical systems (CPS) under false data injection attacks. We describe the CPS under attacks as a Markov decision process (MDP), based on which the secure controller design for CPS under attacks is formulated as an action policy learning using data....

journal article 2023

document

CO₂ utilization in chemical looping gasification and co-gasification of lignocellulosic biomass components over iron-based oxygen carriers: Thermogravimetric behavior, synergistic effect, and reduction characteristics

Kuo, Po Chih (author), Sun, Zhuang (author), Özdemir, F. (author), Aziz, Muhammad (author), Wu, Wei (author)

Efficient CO₂ utilization in the thermochemical conversion of biomass plays an important role in creating a future low-carbon economy. This study attempts to explore the CO₂-assisted chemical looping gasification and co-gasification process of lignocellulosic biomass components (hemicellulose, cellulose, and lignin) with...

journal article 2023

document

Designed Multifunctional Spider Silk Enabled by Genetically Encoded Click Chemistry

Jiang, Bojing (author), Tan, Sin Yen (author), Fang, Shiyu (author), Feng, Xiaohan (author), Park, B.P. (author), Fok, Hong Kiu Francis (author), Yang, Zhongguang (author), Wang, Ri (author), Kou, Songzi (author), Wu, Angela Ruohao (author), Sun, Fei (author)

Spider silk is recognized for its exceptional mechanical properties and biocompatibility, making it a versatile platform for developing functional materials. In this study, a modular functionalization strategy for recombinant spider silk is presented using SpyTag/SpyCatcher chemistry, a prototype of genetically encoded click chemistry. The...

journal article 2023

document

A Secure Robot Learning Framework for Cyber Attack Scheduling and Countermeasure

Wu, Chengwei (author), Yao, Weiran (author), Luo, Wensheng (author), Pan, W. (author), Sun, Guanghui (author), Xie, Hui (author), Wu, Ligang (author)

The problem of learning-based control for robots has been extensively studied, whereas the security issue under malicious adversaries has not been paid much attention to. Malicious adversaries can invade intelligent devices and communication networks used in robots, causing incidents, achieving illegal objectives, and even injuring people....

journal article 2023

document

Tailoring the flow properties of inhaled micronized drug powders by atomic and molecular layer deposition

Zhang, F. (author), Wu, K. (author), La Zara, D. (author), Sun, F. (author), Quayle, Michael J. (author), Petersson, Gunilla (author), Folestad, Staffan (author), Chew, Jia Wei (author), van Ommen, J.R. (author)

For dry powder inhaled formulations, good flow behaviour is vital in re-dispersing the powder. However, inhaled drug powders with a particle size below 10 µm are classified as highly cohesive materials with poor flow characteristics. Here we demonstrate how to alter the flow properties of micronized budesonide powders by depositing different...

journal article 2023

document

Direct Trajectory Optimization of Free-Floating Space Manipulator for Reducing Spacecraft Variation

Shao, X. (author), Yao, Weiran (author), Li, Xiaolei (author), Sun, Guanghui (author), Wu, Ligang (author)

This letter investigates the direct trajectory optimization of the free-floating space manipulator (FFSM). The main purpose is to plan the joint space trajectories to reduce the spacecraft motion due to the joint rotation during the FFSM performing tasks. To improve the calculation efficiency, the adaptive Radau pseudospectral method (A-RPM)...

journal article 2022

document

A cooperative strategy for optimizing vehicle relocations and staff movements in cities where several carsharing companies operate simultaneously

Chang, X. (author), Wu, Jianjun (author), Correia, Gonçalo (author), Sun, Huijun (author), Feng, Ziyan (author)

Carsharing has become a popular travel mode owing to its convenience of use, easy parking, and low cost of using a car by those who only need it occasionally. However, because of the inadequate location of carsharing stations (station-based systems) or vehicles (free-floating systems), effectively requiring expensive and complex relocation...

journal article 2022

document

A Biocatalytic Platform for the Synthesis of Enantiopure Propargylic Alcohols and Amines

Sang, Xianke (author), Tong, Feifei (author), Zeng, Zhigang (author), Wu, Minghu (author), Yuan, Bo (author), Sun, Zhoutong (author), Sheng, Xiang (author), Hollmann, F. (author), Zhang, W. (author)

Propargylic alcohols and amines are versatile building blocks in organic synthesis. We demonstrate a straightforward enzymatic cascade to synthesize enantiomerically pure propargylic alcohols and amines from readily available racemic starting materials. In the first step, the peroxygenase from Agrocybe aegerita converted the racemic...

journal article 2022

document

Template-free preparation of porous Co microfibers from spent lithium-ion batteries as a promising microwave absorber

Wu, Xiao Min (author), Xie, Fei (author), Yao, Yong Lin (author), Sun, Yue (author), Hua, Zhong Sheng (author), Zhao, Zhuo (author), Yang, Y. (author)

In order to take full advantage of the secondary resources, in this paper, we reported a template-free process to prepare porous Co microfibers from spent lithium-ion batteries (LIBs). First, the waste LiCoO₂ powders were leached by oxalic acid at a suitable temperature, and rod-like cobalt oxalate powders were obtained. Second,...

journal article 2022

document

Secure Control for Cyber-Physical Systems under Malicious Attacks

Wu, Chengwei (author), Yao, Weiran (author), Pan, W. (author), Sun, Guanghui (author), Liu, Jianxing (author), Wu, Ligang (author)

This article investigates the secure control problem for cyber-physical systems when the malicious data are injected into the cyber realm, which directly connects to the actuators. Based on moving target defense (MTD) and reinforcement learning, we propose a novel proactive and reactive defense control scheme. First, the system (A,B) is...

journal article 2021

document

Learning Tracking Control for Cyber-Physical Systems

Wu, C. (author), Pan, W. (author), Sun, Guanghui (author), Liu, Jianxing (author), Wu, Ligang (author)

This paper investigates the problem of optimal tracking control for cyber-physical systems (CPS) when the cyber realm is attacked by denial-of-service (DoS) attacks which can prevent the control signal transmitting to the actuator. Attention is focused on how to design the optimal tracking control scheme without using the system dynamics and...

journal article 2021

document

Relocating operational and damaged bikes in free-floating systems: A data-driven modeling framework for level of service enhancement

Chang, Ximing (author), Wu, Jianjun (author), Sun, Huijun (author), Correia, Gonçalo (author), Chen, JianHua (author)

Free-floating bike sharing is an innovative and sustainable travel mode, where shared bikes can be picked up and returned at any proper place on the streets and not just at docking stations. Nevertheless, in these systems, two major problems arise. One is the imbalance of free-floating shared bikes (FFSB) between zones due to one-way trips,...

journal article 2021

document

First demonstration of l-band high-power limiter with gan schottky barrier diodes (Sbds) based on steep-mesa technology

Sun, Y. (author), Kang, Xuanwu (author), Deng, Shixiong (author), Zheng, Yingkui (author), Wei, Ke (author), Xu, Linwang (author), Wu, Hao (author), Liu, Xinyu (author)

Gallium nitride (GaN) has attracted increased attention because of superior material properties, such as high electron saturation velocity and high electrical field strength, which are promising for high-power microwave applications. We report on a high-performance vertical GaN-based Schottky barrier diode (SBD) and its demonstration in a...

journal article 2021

document

Low Leakage and High Forward Current Density Quasi-Vertical GaN Schottky Barrier Diode With Post-Mesa Nitridation

Kang, Xuanwu (author), Sun, Y. (author), Zheng, Yingkui (author), Wei, Ke (author), Wu, Hao (author), Zhao, Yuanyuan (author), Liu, Xinyu (author), Zhang, Kouchi (author)

In this brief, a high-performance quasi-vertical GaN Schottky barrier diode (SBD) on sapphire substrate with post-mesa nitridation process is reported, featuring a low damaged sidewall with extremely low leakage current. The fabricated SBD with a drift layer of 1 μm has achieved a very high ON/OFF current ratio (Iscriptscriptstyle ON...

journal article 2021

document

High-power and broadband microwave detection with a quasi-vertical GaN Schottky barrier diode by novel post-mesa nitridation

Sun, Y. (author), Kang, Xuanwu (author), Deng, Shixiong (author), Zheng, Yingkui (author), Wei, Ke (author), Xu, Linwang (author), Wu, Hao (author), Liu, Xinyu (author)

We report a high-performance GaN Schottky barrier diode (SBD) on a sapphire substrate with a novel post-mesa nitridation technique and its application in a high-power microwave detection circuit. The fabricated SBD achieved a very high forward current density of 9.19 kA cm-2 at 3 V, a low specific on-resistance (RON,sp) of 0.22 mO cm2 and...

journal article 2021

document

High performance mixed potential type No₂ gas sensor based on porous YSZ layer formed with graphite doping

Hong, Hao (author), Sun, J. (author), Wu, Cinan (author), Liu, Zewen (author)

High performance mixed potential type NO₂ sensors using porous yttria-stabilized zirconia (YSZ) layers doped with different concentration graphite as solid electrolyte and LaFeO₃ as sensing electrode were fabricated and characterized. LaFeO₃ was prepared by a typical citrate sol–gel method and characterized...

journal article 2019

document

Lumen Degradation Lifetime Prediction for High-Power White LEDs Based on the Gamma Process Model

Ibrahim, M.S. (author), Fan, J. (author), Yung, Winco K.C. (author), Wu, Zeyu (author), Sun, B. (author)

Nowadays, due to the advancement of design and manufacturing technology, there are many consumer products with high reliability. Similarly, the competition in the business sector influences the product development time to become shorter and that makes it difficult for manufacturers to evaluate the reliability of current products before new...

journal article 2019

document

A recognition model of driving risk based on Belief Rule-Base methodology

Sun, Chuan (author), Wu, Chaozhong (author), Chu, Duanfeng (author), Lu, Z. (author), Tan, Jian (author), Wang, Jianyu (author)

This paper aims to recognize driving risks in individual vehicles online based on a data-driven methodology. Existing advanced driver assistance systems (ADAS) have difficulties in effectively processing multi-source heterogeneous driving data. Furthermore, parameters adopted for evaluating the driving risk are limited in these systems. The...

journal article 2018

document

Research on the mechanical, thermal, induction heating and healing properties of steel slag/steel fibers composite asphalt mixture

Liu, Quantao (author), Li, Bin (author), Schlangen, E. (author), Sun, Yihan (author), Wu, Shaopeng (author)

In this paper, steel slag/steel fiber composite asphalt mixture were prepared. The effects of the addition of steel slag and/or steel fibers on the mechanical, thermal, induction heating and healing properties of asphalt mixture were investigated. The results showed that adding steel slag and/or steel fibers improves the water stability,...

journal article 2017