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污水监测追踪新冠病毒的时空动态变化（英文）

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Engineering 2024年第9期 70-77页

作者：郑夏婉 Kathy Leung 徐晓庆邓妤张玉琳陈熙 Chung In Yau Kenny W.K.Hui Eddie Pak Ho-kwong Chui 杨绒 Hein Min Tun Gabriel Matthew Leung Joseph Tsz Kei Wu Malik Peiris Leo Lit Man Poon 张彤 Environmental Microbiome Engineering and Biotechnology Lab Center for Environmental Engineering Research Department of Civil Engineering The University of Hong Kong WHO Collaborating Centre for Infectious Disease Epidemiology and Control School of Public Health Li Ka Shing Faculty of Medicine The University of Hong Kong Laboratory of Data Discovery for Health Litd.(D24H) The University of Hong Kong-Shenzhen Hospital School of Public Health Li Ka Shing Faculty of Medicine The University of Hong Kong Drainage Services Department The Government of the Hong Kong Special Administrative Region Environmental Protection Department The Government of the Hong Kong Special Administrative Region The Jockey Club School of Public Health and Primary Care Faculty of Medicine The University of Hong Kong HKU-Pasteur Research Pole The University of Hong Kong

Wastewater surveillance（WWS） can leverage its wide coverage, population-based sampling, and high monitoring frequency to capture citywide pandemic trends independent of clinical surveillance. Here we conducted a nine months daily WWS for severe acute respiratory syndrome coronavirus 2（SARS-CoV-2） from 12 wastewater treatment plants（WWTPs）, covering approximately 80% of the population,to monitor infection dynamics in Hong Kong, China. We found that the SARS-CoV-2 virus concentration in wastewater was correlated with the daily number of reported cases and reached two pandemic peaks three days earlier during the study period. In addition, two different methods were established to estimate the prevalence/incidence rates from wastewater measurements. The estimated results from wastewater were consistent with findings from two independent citywide clinical surveillance programmes(rapid antigen test（RAT） surveillance and serology surveillance), but higher than the cases number reported by the Centre for Health Protection（CHP） of Hong Kong, China. Moreover, the effective reproductive number（R_t） was estimated from wastewater measurements to reflect both citywide and regional transmission dynamics. Our findings demonstrate that large-scale intensive WWS from WWTPs provides cost-effective and timely public health information, especially when the clinical surveillance is inadequate and costly. This approach also provides insights into pandemic dynamics at higher spatiotemporal resolutions, facilitating the formulation of effective control policies and targeted resource allocation.

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Optimal decentralized control of large scale systems

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Control Theory and Technology 2016年第4期14卷 287-313页

作者： Xiao Qi SHI Daniel E. DAVISON Raymond kwong Edward J. DAVISON Systems Control Group Department of Electrical and Computer Engineering University of Toronto Ontario Canada MSS 3G4 Department of Electrical and Computer Engineering University of Waterloo Ontario Canada N2L 3G1

This paper presents a new optimized decentralized controller design method for solving the tracking and disturbance rejection problems for large-scale linear time-invariant systems, using only low-order decentralized controllers. To illustrate the type of results which can be obtained using the new optimized decentralized control design method, the control of a large flexible space structure is studied and compared with the standard centralized LQR-observer controller. The order of the resultant decentralized controller is much smaller than that of the standard centralized LQR-observer controller. The proposed controller also has certain fail-safe properties and, in addition, it can be five orders of magnitude more robust than the standard LQR-observer controller based on their real stability radii. The new decentralized controller design method is applied to a large flexible space structure system with 5 inputs and 5 outputs and of order 24.

关键词： Decentralized control multivariable control PID control robustness optimization large-scale systems flexiblestructures

Effects of Nitridation Temperature on Characteristics of Gallium Nitride Thin Films Prepared Via Two-Step Method

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Acta Metallurgica Sinica(English Letters) 2015年第3期28卷 362-366页

作者： Chee Yong Fong Sha Shiong Ng Fong kwong Yam Haslan Abu Hassan Zainuriah Hassan Nano-Optoelectronics Research and Technology Laboratory School of PhysicsUniversiti Sains Malaysia

In this research,the growth of GaN thin films on c-plane sapphire（0001） substrates via two-step method without the assist of buffer layer and catalysts was ***,gallium oxide（Ga_2O_3） thin films were deposited on sapphire substrates by radio frequency magnetron sputtering *** deposited Ga_2O_3 thin films were then nitridated at various *** this research,attention is focused on the influence of nitridation temperatures on the structural and optical properties of the synthesized GaN thin *** is revealed that 950 ℃ is the optimal nitridation temperature for synthesizing hexagonal wurtzite GaN thin film with preferential（0002） growth direction.

关键词： Sputtering Nitridation Gallium oxide Gallium nitride

k-dimensional hashing scheme for hard disk integrity verification in computer forensics

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第10期12卷 809-818页

作者： Zoe Lin JIANG Lucas Chi kwong HUI Siu Ming YIU Kam Pui CHOW School of Computer Science and Technology Harbin Institute of Technology Shenzhen Graduate School Department of Computer Science The University of Hong Kong

Verifying the integrity of a hard disk is an important concern in computer forensics,as the law enforcement party needs to confirm that the data inside the hard disk have not been modified during the investigation.A typical approach is to compute a single chained hash value of all sectors in a specific ***,this technique loses the integrity of all other sectors even if only one of the sectors becomes a bad sector occasionally or is modified *** this paper we propose a k-dimensional hashing scheme,kD for short,to distribute sectors into a kD space,and to calculate multiple hash values for sectors in k dimensions as integrity *** the integrity of the sectors can be verified depending on any hash value calculated using the sectors,the probability to verify the integrity of unchanged sectors can be high even with bad/modified sectors in the hard *** show how to efficiently implement this kD hashing scheme such that the storage of hash values can be reduced while increasing the chance of an unaffected sector to be verified *** results of a 3D scheme show that both the time for computing the hash values and the storage for the hash values are reasonable.

关键词： Computer forensics Digital evidence Hard disk integrity k-dimensional hashing

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污水中新型冠状病毒监测技术的进展与启示

科学通报 2024年第3期69卷 362-369页

作者：邓妤徐晓庆郑夏婉梁卓伟徐浩光李迎慧扈庆华杨敏黄霞唐宋张岚张彤香港大学土木工程系环境工程研究中心环境微生物组工程与技术实验室中国香港999077 香港大学李嘉诚医学院公共卫生学院中国香港999077 香港特别行政区政府环境保护署中国香港999077 深圳市疾病预防控制中心深圳518055 中国科学院生态环境研究中心北京100085 清华大学环境学院北京100084 中国疾病预防控制中心环境与健康相关产品安全所北京100021

污水流行病学的概念最早于2001年提出[1],最初是通过追踪污水中多种与人群健康和行为相关的化学与生物标记物,对使用毒品与非法药物的群体进行精准溯源[2],或是预警、跟踪和遏制传染病的暴发及其在社区中的传播[3].其中一个典型的应用... 详细信息

污水流行病学的概念最早于2001年提出[1],最初是通过追踪污水中多种与人群健康和行为相关的化学与生物标记物,对使用毒品与非法药物的群体进行精准溯源[2],或是预警、跟踪和遏制传染病的暴发及其在社区中的传播[3].其中一个典型的应用实例是2013年以色列在常规污水监测中发现了被认为已经根除的脊髓灰质炎病毒,随即据此展开大规模疫苗接种从而成功避免了小儿麻痹症在当地的再次暴发.

关键词：脊髓灰质炎病毒生物标记物人群健康污水监测监测技术进展与启示暴发

Passively Q-switched and femtosecond modelocked erbium-doped fiber laser based on a 2D palladium disulfide(PdS2) saturable absorber

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Photonics Research 2020年第4期8卷 511-518页

作者： PING kwong CHENG CHUN YIN TANG XIN YU WANG LONG-HUI ZENG YUEN HONG TSANG Department of Applied Physics and Materials Research Center The Hong Kong Polytechnic UniversityHung HornKowloonHong KongChina

Stable Q-switched and mode-locked erbium-doped fiber lasers(EDFLs)are first demonstrated by using the novel layered palladium disulfide(PdS2),a new member of group 10 transition metal dichalcogenides(TMDs)-based saturable absorbers(SAs).Self-started Q-switched operation at 1567 nm was achieved with a threshold pump power of 50.6 *** modulation ranges of pulse duration and repetition rate were characterized as 12.6-4.5μs and 17.2-26.0 kHz,***,a mode-locked EDFL was also obtained with a pump power threshold of 106.4 *** achieved pulse duration is 803 fs,corresponding to a center wavelength of 1565.8 nm and4.48 nm 3 dB *** the best of our knowledge,the achieved pulse duration of the mode-locked EDFL in this work is the narrowest compared with all other group 10 TMD SA-based lasers.

关键词： Passively Q-switched femtosecond modelocked erbium-doped fiber laser a 2D palladium disulfide

颅脑有限元模型演化规律及其生物力学研究进展

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医用生物力学 2014年第6期29卷 576-581,588页

作者：羊玢曹立波陈宁 Tse kwong Ming lee Heow Pueh 湖南大学汽车车身先进设计制造国家重点实验室长沙410082 南京林业大学汽车与交通工程学院南京210037 新加坡国立大学机械工程系新加坡117576

交通事故中头颈部损伤因其较高的致命性,已成为最严重的损伤类型。有限元模型在创伤性脑损伤生物力学机理研究中得到日益广泛应用。回顾头颈部有限元模型的生物力学研究历史和现状,并阐述车辆碰撞交通事故中人体颅脑典型交通伤演化规律... 详细信息

交通事故中头颈部损伤因其较高的致命性,已成为最严重的损伤类型。有限元模型在创伤性脑损伤生物力学机理研究中得到日益广泛应用。回顾头颈部有限元模型的生物力学研究历史和现状,并阐述车辆碰撞交通事故中人体颅脑典型交通伤演化规律和生物力学研究进展,探索头颈部损伤安全防护的方法,以期为车辆碰撞事故中人体颅脑损伤生物力学研究和相应的汽车安全防护装置研制提供理论依据。

关键词：有限元模型颅脑损伤生物力学演化规律损伤防护

Stress analysis of the TMSR graphite component under irradiation conditions

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Nuclear Science and Techniques 2018年第12期29卷 21-29页

作者： Xiong Yang Yan-Tao Gao Yang Zhong Dong Ding Derek-kwong-Lai Tsang Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Science Beijing 100049China

TMSR uses nuclear graphite as a neutron moderator, a reflector, and the structural material, and utilizes molten salt as a coolant. When running normally, the graphite components are immersed in the molten ***, the nuclear graphite comes into direct contact with the molten salt, which infiltrates the open pores of the nuclear graphite. This infiltration may influence the stress analysis of the graphite component. In this study, a User Material subroutine was used to analyze the stress distribution of the graphite component, both with and without molten salt infiltration. Many influence factors were taken into consideration, such as the dose gradient, the shape of the permeation zone, and the permeation area. The results show that the dose gradient, shape, and area of the permeation zone all significantly influence the stress distribution. Furthermore, the results of the stress analysis indicate that for a regular graphite component with a square cross section, the peak maximum principal stress value occurs at the center of the cross section, and the symmetry of the maximum principal stress distributions was modified by quarter circle and half ellipse permeation zones.

关键词：石墨部件压力分析直接接触影响因素压力分布熔融浸透

LOX upregulates FAK phosphorylation to promote metastasis in osteosarcoma

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Genes & Diseases 2023年第1期10卷 254-266页

作者： Xiang Chen Margaret Clement MJohn Hicks Poonam Sarkar MWaleed Gaber Tsz-kwong Man Department of Pediatrics Baylor College of MedicineOne Baylor PlazaHoustonTX 77030USA Department of Pathology Baylor College of MedicineOne Baylor PlazaHoustonTX 77030USA Dan L.Duncan Comprehensive Cancer Center 7200 Cambridge StreetHoustonTX 77054USA Texas Children's Cancer and Hematology Centers 1102 Bates StHoustonTX 77030USA

Osteosarcoma is a malignant bone tumor that commonly occurs in the pediatric *** the use of chemotherapy and surgery,metastasis remains to be the leading cause of death in patients with *** have previously reported that cytoplasmic mislocalization of p27 is associated with a poor outcome in *** this study,we further show that lysyl oxidase(LOx)expression was associated with p27 *** is an enigmatic molecule that acts as a tumor suppressor or a metastatic promoter;however,its role in osteosarcoma is still ***,we performed both in vitro and in vivo analyses to dissect the role of Lox in *** result of our survival analysis indicated that Lox expression significantly correlated with a poor outcome in osteosarcoma with or without controlling for the initial metastasis status(P<0.05).Functionally,we found that higher LoX expression promoted osteosarcoma cell proliferation,migration,and invasiveness in vitro and produced a higher number of mice with pulmonary metastases in an orthotopic xenograft mouse ***,phospho-FAK was increased in osteosarcoma cells with high LOX *** results further showed that FAK inhibition significantly reduced tumor cell proliferation and migration in vitro as well as LoX-mediated metastasis in ***,our findings suggest that there is a novel link between p27 mislocalization and LOX *** plays a pivotal role in osteosarcoma metastasis by upregulating FAK *** inhibition may constitute a promising therapeutic strategy to reduce the development of metastasis in osteosarcoma with Lox overexpression.

关键词： Focal adhesion kinase Lysyl oxidase Metastasis Osteosarcoma