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Properties of Cementitious Rendering Mortar Prepared with Recycled Fine Aggregates

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Journal of Wuhan university of Technology(Materials Science) 2010年第6期25卷 1053-1056页

作者：潘智生 department of Civil and Structural engineering The Hong Kong Polytechnic University

The results of an experimental study on investigating the properties of cementitious rendering mortars prepared with a recycled fine aggregate（RA） were *** RA was obtained from a recycling plant in which mixed demolition wastes were processed by mechanical crushing,sieving and sorting *** series of rendering mortar mixes were prepared with a constant water/cement and a constant aggregate/cement ratios of 0.55 and 3 *** sand and natural crushed rock fine were originally used in the two series separately,and they were consistently replaced by 2.%,50%,75% and 100% by the recycled *** experimental results showed that mechanical properties,such as compressive strength,flexural strength and modulus of elasticity of the mortars prepared with the RA were lower than the mortars made with the natural ***,the bond strength at the interface between the mortar and masonry bricks determined by the Triplet test was found to be higher for the mortars prepared with the RA.

关键词： rendering mortar recycled fine aggregate triplet test mechanical properties

Theoretical insights into the structures and fundamental properties of pnictogen nitrides

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Chinese Physics B 2024年第9期33卷 474-479页

作者： Jingjing Wang Panlong kong Dingmei Zhang Defang Gao Zaifu Jiang Wei Dai School of Mathematics and Physics Jingchu University of TechnologyJingmen 448000China

Recent experimental advancements reported a chemical reaction between antimony and nitrogen under high temperature and high pressure,yielding crystalline antimony nitride(Sb_(3)N_(5))with an orthorhombic *** by this statement,we calculate the stability,elastic properties,electronic properties and energy density of the Cmc2.(1) structure for pnictogen nitrides X_(3)N_(5)(X=P,As,Sb,and Bi)using first-principles calculations combined with particle swarm optimization *** of formation enthalpies,elastic constants and phonon spectra show that P_(3)N_(5),As_(3)N_(5) and Sb_(3)N_(5) are thermodynamically,mechanically and kinetically stable at 35 GPa,whereas Bi_(3)N_(5) is mechanically and kinetically stable but thermodynamically *** computed electronic density of states shows strong covalent bonding between the N atoms and the phosphorus group atoms in the four compounds,confirmed by the calculated electronic localization *** also calculate the energy densities for Sb_(3)N_(5) and find it to be a potentially high-energy-density material.

关键词： pnictogen nitrides structural stability electronic property energy density

Chaos-based encryption for fractal image coding

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Chinese Physics B 2012年第1期21卷 115-126页

作者：袁正雄黄国和 department of electronic {2. City University of Hong Kong

A chaos-based cryptosystem for fractal image coding is proposed. The Renyi chaotic map is employed to determine the order of processing the range blocks and to generate the keystream for masking the encoded sequence. Compared with the standard approach of fraetal image coding followed by the Advanced Encryption Standard, our scheme offers a higher sensitivity to both plaintext and ciphertext at a comparable operating efficiency. The keystream generated by the Renyi chaotic map passes the randomness tests set by the United States National Institute of Standards and Technology, and so the proposed scheme is sensitive to the key.

关键词： chaos cryptography joint image compression and encryption fractal image coding

Predicting the Maintainability of Open Source Software Using Design Metrics

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Wuhan university Journal of Natural Sciences 2008年第1期13卷 14-20页

作者： ZHOU Yuming1,2. XU Baowen1,3 1. School of Computer Science and engineering, Southeast university, Nanjing 2.0096, Jiangsu,{2. 2. department of Computing, hong kong polytechnic university, hong kong, china 3. Jiangsu Institute of Software Quality, Nanjing 2.0096, Jiangsu,{2. School of Computer Science and engineering Southeast University Nanjing China department of Computing Hong Kong Polytechnic University Hong Kong China Jiangsu Institute of Software Quality Nanjing China

This paper empirically investigates the relationships between 15 design metrics and maintainability of 148 Java open source software. The results show that size and complexity metrics are strongly related to the maintainability of open source software. However, cohesion and coupling, as currently captured by existing metrics, do not seem to have a significant impact on maintainability. When used together, these metrics can predict system maintainability fairly accurately （mean MREs below 30%）.

关键词： open source: object-oriented maintainability metric prediction regression

Modeling uncertainty in geographic information and analysis

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Science china(Technological Sciences) 2008年第S1期51卷 38-47页

作者： SHI WenZhong Advanced Research Centre for Spatial Information Technology,department of Land Surveying and Geo-Informatics,the{2.,Hung Hom,Kowloon,hong kong,china 1. Advanced Research Centre for Spatial Information Technology Department of Land Surveying and Geo-Informatics the Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong China

Uncertainty modeling and data quality for spatial data and spatial analyses are im-portant topics in geographic information science together with space and time in geography,as well as spatial analysis. In the past two decades,a lot of efforts have been made to research the uncertainty modeling for spatial data and analyses. This paper presents our work in the research. In particular,four progresses in the re-search are given out: (a) from determinedness-to uncertainty-based representation of geographic objects in GIS; (b) from uncertainty modeling for static data to dy-namic spatial analyses; (c) from modeling uncertainty for spatial data to models; and (d) from error descriptions to quality control for spatial data.

关键词： uncertainty quality control spatial data spatial analysis spatial model

Imbalanced rock burst assessment using variational autoencoder-enhanced gradient boosting algorithms and explainability

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Underground Space 2024年第4期17卷 226-245页

作者： Shan Lin Zenglong Liang Miao Dong hongwei Guo hong Zheng Key Laboratory of Urban Security and Disaster engineering Ministry of EducationBeijing University of TechnologyBeijing 100124China department of Civil and Environmental engineering The Hong Kong Polytechnic University(PolyU)Hung HomKowloon 999077Hong KongChina

We conducted a study to evaluate the potential and robustness of gradient boosting algorithms in rock burst assessment,established a variational autoencoder(VAE)to address the imbalance rock burst dataset,and proposed a multilevel explainable artificial intelligence(XAI)tailored for tree-based ensemble *** collected 537 data from real-world rock burst records and selected four critical features contributing to rock burst ***,we employed data visualization to gain insight into the data’s structure and performed correlation analysis to explore the data distribution and feature ***,we set up a VAE model to generate samples for the minority class due to the imbalanced class *** conjunction with the VAE,we compared and evaluated six state-of-theart ensemble models,including gradient boosting algorithms and the classical logistic regression model,for rock burst *** results indicated that gradient boosting algorithms outperformed the classical single models,and the VAE-classifier outperformed the original classifier,with the VAE-NGBoost model yielding the most favorable *** to other resampling methods combined with NGBoost for imbalanced datasets,such as synthetic minority oversampling technique(SMOTE),SMOTE-edited nearest neighbours(SMOTE-ENN),and SMOTE-tomek links(SMOTE-Tomek),the VAE-NGBoost model yielded the best ***,we developed a multilevel XAI model using feature sensitivity analysis,Tree Shapley Additive exPlanations(Tree SHAP),and Anchor to provide an in-depth exploration of the decision-making mechanics of VAE-NGBoost,further enhancing the accountability of treebased ensemble models in predicting rock burst occurrences.

关键词： Gradient boosting VAE Ensemble learning Explainable artificial intelligence(XAI) Rock burst

engineering singlet and triplet excitons of TADF emitters by different host-guest interactions

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Aggregate

Aggregate 2024年第1期5卷 337-344页

作者： Wei Zhang Jie kong Rui Zhi An Jiachen Zhang Yujie Zhou Lin-Song Cui Meng Zhou Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefeiChina Key Laboratory of Precision and Intelligent Chemistry University of Science and Technology of China(USTC)HefeiChina CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiChina

Understanding the host-guest interactions for thermally activated delayed fluorescence(TADF)emitters is critical because the interactions between the host matrices and TADF emitters enable precise control on the optoelectronic performance,whereas technologically manipulating the singlet and triplet excitons by using different kinds of host-guest interactions remains ***,we report a comprehensive picture that rationalizes host-guest interaction-modulated exciton recombination by using time-resolved *** found that the early-time relaxation is accelerated in polar polymer because dipole-dipole interaction facilitates the stabilization of the 1CT ***,an opposite trend is observed in longer delay time,and faster decay in the less polar polymer is ascribed to theπ-πinteraction that plays the dominant role in the later stage of the excited *** findings highlight the technological engineering singlet and triplet excitons using different kinds of host-guest interactions based on their electronic characteristics.

关键词： host-guest interaction singlet TADF triplet

CONTACT DEFORMATION AND PRE-CONTROL OF TRANSMISSION PROPERTIES OF POINT CONJUGATE GEAR

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Chinese Journal of Mechanical engineering 2000年第1期13卷 76-80页

作者： Liu Huran Yuan Wenhui (department of Mechanical engineering, Changsha Railway Institute) Li Rongbin (The{2.) 长沙铁道学院湖南长沙香港理工大学香港

According to spatial conjugate principle and theory of elastic contact, a method to pre-control transmission properties and contact mark of point meshing gear is presented, while the deformation of tooth surface is un... 详细信息

关键词： Elastic Contact Deformation Meshing Gear

Determination of ocean tide loading displacements in hong kong using GPS technique

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Science china Earth Sciences 2010年第7期53卷 993-1007页

作者： YUAN LinGuo1,3, DING XiaoLi1, SUN HePing2. Zhong Ping1,3 & CHEN Wu1 1 department of Land Surveying and Geo-Informatics, The{2., Kowloon, hong kong, china 2.Key Laboratory of Dynamic Geodesy, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, china 3 department of Surveying engineering, School of Civil engineering, Southwest Jiaotong university, Chengdu 610031, china 1. department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University Kowloon Hong Kong China3. Department of Surveying Engineering School of Civil Engineering Southwest Jiaotong University Chengdu 610031 China2. Key Laboratory of Dynamic Geodesy Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China

Ocean tide loading (OTL) displacements of eight principal constituents at 12.sites in hong kong were determined using more than eight years of continuous GPS observations. Parameters of the OTL displacements were estimated using daily GPS solutions obtained with precise point positioning (PPP) technique. The results were compared with predictions from seven latest global ocean tide models. Gravity measurements of OTL in hong kong were also used to validate the GPS results. The study shows that the results from both the GPS and gravity measurements agree best with the GOT4.7 and NAO99b models, when the K1 and K2.constituents are excluded. The agreements between the GPS and the model estimates are generally at sub-millimeter level in both the horizontal and vertical directions, except for S2. K2.and K1 constituents that have relatively larger errors. After removing the systematic biases between the GPS and the model estimates, the misfits of M2. S2. N2. O1, P1 and Q1 at all sites are within 0.5 and 1.0 mm in the horizontal and the vertical directions, respectively, whereas K1 and K2.show relatively larger misfits of up to 2.3 mm. Both the GPS and the gravity S2.estimates have large biases with unknown reasons when compared with the modeled values, which needs to be further investigated. The study demonstrates that GPS is capable of estimating the OTL displacements with the same accuracy as the model predictions, especially for coastal areas.

关键词： GPS ocean tide loading ocean tide model site displacement