174 research outputs found

    Reform of the Chinese housing system in the 1990s

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    This thesis considers the Chinese housing reforms of the 1990s in the context of the previous system and assesses their impact. The PRC housing system evolved gradually from 1949 onwards. Described as a "work unit welfare-in-kind housing provision system", it was widely perceived as having fundamental flaws and was targeted for reform from 1978 onwards. Following a period of protracted experimentation from 1978 to 1990, the Chinese government launched a new wave of comprehensive housing reforms from the beginning of the 1990s. The four key early measures were: rent increases, the sale of public housing, the creation of the Housing Accumulation Fund, and the development of Economic and Practical Housing. However, these changes had only limited impact, and a new policy, monetised housing provision, was introduced in the late 1990s, along with a series of ancillary policies. This aimed to prohibit the allocation of housing to employees by work units, directing them instead to provide a cash allowance as part of wages; employees were directed to purchase or rent accommodation in the market. This was intended to speed up the process towards a market economy in the housing sector. The fact that housing reforms have such a major impact on all urban families makes them extremely sensitive. At the same time, reforms in other areas of the economy are dependent on the successful implementation of housing reforms. This thesis analyses the impact of the reforms and assesses how far they have succeeded in making fundamental changes to the housing provision system

    Liuzhou Fantastic Stones Museum

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    The natural beauty of its landscapes and rivers underpin China’s culture. For thousands of years the rivers along with other geological forces have fashioned natural artifacts that capture this cultural history. The Hongshuihe is a magical river that flows across northern Guangxi Province into the Liujiang River just south of Liuzhou City. The unique physics of this River produce natural art in the form of ornamental stones. Because these stones served traditionally as tribute, they became part of the context of Chinese history and cultural development. Interest in these natural treasures rekindled in Liuzhou in the wake of the “Cultural Revolution” and since then the city has been dedicated to finding, preserving and making these natural cultural treasures available to its people, and the people of China and the world. The poster looks briefly at the overall classification of ornamental stones then explores the cultural aspects of appreciation and play by introducing some of Liuzhou’s finest water stones

    Experimental behaviour of very high-strength concrete-encased steel composite column subjected to axial compression and end moment

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    [EN] A type of cost-effective and very high strength concrete (VHSC) with 28-day compressive strength of 100-150 MPa is developed for applications in concrete-encased steel composite column constructions. This paper experimentally investigates the structural behaviour of VHSC encased steel composite columns based on a series of pure compression and eccentric compression tests. It is found that such high-strength composite column exhibits brittle post peak behaviour and low ductility but with acceptable compressive resistance. Throughout the tests, the main failure of VHSC encased column under compressive load is brittle spalling of concrete followed by local buckling of the reinforcement bars. The splitting and slippage may occur between concrete and steel section due to bending downward action. The confinement effect by the shear stirrups designed based on normal reinforced concrete codes may not be sufficient. Composite column subjected to initial flexural cracking due to end moment load with large eccentricity may experience degradation in the stiffness and ultimate resistance so that plastic design resistance may not be achieved. Analytical studies show that the N-M interaction model based on current design codes may over-predict the combined resistance of the composite columns. Therefore, a modified elastic-plastic design approach based on strain compatibility is developed to evaluate the compressive resistance of concrete encased composite columns. The validation against the test data shows a reasonable and conservative estimation on the combined resistance of VHSC encased composite columns.Huang, Z.; Huang, X.; Li, W.; Zhou, Y.; Sui, L.; Liew, JY. (2018). Experimental behaviour of very high-strength concrete-encased steel composite column subjected to axial compression and end moment. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 323-329. https://doi.org/10.4995/ASCCS2018.2018.7034OCS32332

    Stage-by-stage Wavelet Optimization Refinement Diffusion Model for Sparse-View CT Reconstruction

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    Diffusion models have emerged as potential tools to tackle the challenge of sparse-view CT reconstruction, displaying superior performance compared to conventional methods. Nevertheless, these prevailing diffusion models predominantly focus on the sinogram or image domains, which can lead to instability during model training, potentially culminating in convergence towards local minimal solutions. The wavelet trans-form serves to disentangle image contents and features into distinct frequency-component bands at varying scales, adeptly capturing diverse directional structures. Employing the Wavelet transform as a guiding sparsity prior significantly enhances the robustness of diffusion models. In this study, we present an innovative approach named the Stage-by-stage Wavelet Optimization Refinement Diffusion (SWORD) model for sparse-view CT reconstruction. Specifically, we establish a unified mathematical model integrating low-frequency and high-frequency generative models, achieving the solution with optimization procedure. Furthermore, we perform the low-frequency and high-frequency generative models on wavelet's decomposed components rather than sinogram or image domains, ensuring the stability of model training. Our method rooted in established optimization theory, comprising three distinct stages, including low-frequency generation, high-frequency refinement and domain transform. Our experimental results demonstrate that the proposed method outperforms existing state-of-the-art methods both quantitatively and qualitatively

    Quantum Cellular Neural Networks

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    We have previously proposed a way of using coupled quantum dots to construct digital computing elements - quantum-dot cellular automata (QCA). Here we consider a different approach to using coupled quantum-dot cells in an architecture which, rather that reproducing Boolean logic, uses a physical near-neighbor connectivity to construct an analog Cellular Neural Network (CNN).Comment: 7 pages including 3 figure

    Taxonomic Abundance at Panxian Dadong, a Middle Pleistocene Cave in South China

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    The faunal assemblage from the site of Panxian Dadong provides evidence for a general continuity in species representation throughout a period of approximately 120 kya. Taxonomically, faunal material from Dadong includes classic taxa of the Middle Pleistocene Ailuropoda-Stegodon faunal complex of South China. Taxonomic abundance measures document a sample that is rich in large ungulate species including rhinoceros, stegodonts, and large bovids. These data are further examined in light of assemblage formation processes, temporal distribution, and environmental context. Taphonomic data that demonstrate the presence and activities of bonecollecting species (including porcupines, hominids, and large and small carnivores) suggest that Dadong Cave was an attractive shelter that saw many uses during the period analyzed. These include hominid foraging, porcupine bone collecting, and carnivore scavenging and hunting. KEYWORDS: Middle Pleistocene, South China, Ailuropoda-Stegodon fauna, hominid

    Thermal Cycling Life Prediction of Sn-3.0Ag-0.5Cu Solder Joint Using Type-I Censored Data

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    Because solder joint interconnections are the weaknesses of microelectronic packaging, their reliability has great influence on the reliability of the entire packaging structure. Based on an accelerated life test the reliability assessment and life prediction of lead-free solder joints using Weibull distribution are investigated. The type-I interval censored lifetime data were collected from a thermal cycling test, which was implemented on microelectronic packaging with lead-free ball grid array (BGA) and fine-pitch ball grid array (FBGA) interconnection structures. The number of cycles to failure of lead-free solder joints is predicted by using a modified Engelmaier fatigue life model and a type-I censored data processing method. Then, the Pan model is employed to calculate the acceleration factor of this test. A comparison of life predictions between the proposed method and the ones calculated directly by Matlab and Minitab is conducted to demonstrate the practicability and effectiveness of the proposed method. At last, failure analysis and microstructure evolution of lead-free solders are carried out to provide useful guidance for the regular maintenance, replacement of substructure, and subsequent processing of electronic products

    Lithic Raw Material Use at the Late Middle Pleistocene Site of Panxian Dadong

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    The possibility of selective use of lithic raw material in the Middle Pleistocene cave deposits of Panxian Dadong is examined in order to evaluate hominid strategies of resource management. Limestone, chert, and basalt, available in or nearby the cave, were differentially used for the production of tools and unretouched flakes. Limestone was predominantly used to produce expedient tools, unretouched flakes were most commonly made of basalt, and chert was most frequently used to produce retouched flakes and tools. Patterns in the reduction sequence for each raw material also indicate that these lithic resources were selectively used. The early stages of core reduction are clearly represented in basalt flakes, whereas chert artifacts exhibit the later stages of tool production and the greatest degree of resharpening. When the selection of raw material is examined through time, over a span of more than 100,000 years, two patterns are clear. The proportion of chert and basalt and the overall frequency of artifacts increases. These changes in the frequency and selection of raw material occur without a techno-typological change. The major shifts in raw material usage correlate with a colder climatic regime and may relate to the intensified use of the cave for animal carcass processing and shelter. KEYWORDS: Middle Pleistocene, lithics, reduction sequence, hominid
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