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ISSN 1000-0585
CN 11-1848/P
Started in 1982
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  • Table of Content
      , Volume 55 Issue 9 Previous Issue    Next Issue
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    BUILDING SCIENCE
    Social technical analysis of urban household residential carbon emissions in China
    LIU Nianxiong, MO Dan, WANG Muzhou, ZHANG Jingnan
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 933-939.  
    Abstract   PDF (3070KB) ( 593 )
    Urban household carbon emission reduction is an important research field under the current background of global climate change and quick urbanization process in China. This paper introduces a social technical analysis of household residential carbon emissions. Building and occupant data of sample households was collected through post occupancy monitoring, electricity and gas meter records, photographs and questionnaires. The data provides insight into different household patterns for controlling the HVAC (heating, ventilation and air conditioning) systems. The case study relates the occupant behavior, thermal environment and energy consumption. The result can serve as tools for informing occupants about low carbon lifestyles and more energy efficient ways to control the thermal environment.
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    CIVIL ENGINEERING
    Destructive effect of steel slag coarse aggregate on the concrete under autoclaved condition
    MI Guidong, WANG Qiang, WANG Weilun
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 940-944.  
    Abstract   PDF (3033KB) ( 1125 )
    This study analyzes the destructive effect of steel slag coarse aggregate on concrete with bad steel slag. The destructive effect of steel slag coarse aggregate on different strength concrete samples was investigated by autoclave tests of the steel slag coarse aggregate and the concrete containing the steel slag coarse aggregate. The free CaO and MgO mass ratios of the steel slag were 4.83% and 4.76%. The results show that the free CaO and the minerals containing MgO react rapidly at high temperatures, which crushes the steel slag aggregate due to the interior expansion stresses. The concrete containing the steel slag coarse aggregate might be damaged by the expansion stresses caused by the steel slag. The concrete damage is more severe with higher steel slag coarse aggregate mass ratios. Though the higher strength concrete can resist higher interior expansion stresses caused by the steel aggregate, the aggregate content should still be strictly controlled. For the steel slag used in this paper, the steel slag coarse aggregate mass ratios should be less than 40%.
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    HYDRAULIC ENGINEERING
    Livelihood resources and sustainable development of relocated people for dam construction: An institutional model
    CHEN Wenchao, QIANG Maoshan, XIA Bingqing, ZHENG Tengfei
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 945-949.  
    Abstract   PDF (1109KB) ( 486 )
    The limitations of the traditional compensation policy based on material losses are the main factor that prevents relocated people from recovering from resettlement. This paper constructs a model of their livelihood resources and the sustainable development costs for people based on the Sustainable Livelihoods Framework for the China context, which relates the livelihood resources, boundary conditions, survival strategies and sustainable output development. Data collected from 571 migrants from 7 relocated sites in Southwest China was used in the structural equation modeling to verify the models accuracy. The model indicates that livelihood resources change with the initial boundary condition which leads to different survival strategies and different sustainable development outputs. Then, the strategies and outputs will have a feedback effect that affects the boundary conditions and livelihood resources. The process continues until the whole system balances.
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    Supervisor management and evaluation method based on real-time tracking
    JIANG Hanchen, LIN Peng, QIANG Maoshan
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 950-956,963.  
    Abstract   PDF (2804KB) ( 853 )
    A method was developed to provide prompt management and evaluation of supervisory staff behavior on dam construction sites. The system uses smart phones embedded with global positioning system (GPS) module for real-time location tracking. The supervisor location information is collected and uploaded to the server by the smart phones. The server processes the data and displays the locations and paths of each supervisor on a web page for real-time monitoring. Three indicators, the field work time, effective work time and effective working range, were developed to identify the specific work context and measure the supervisor workloads. The method was verified by simulated field tests that show that the method can accurately determine the real-time positions of the supervisors and can identify their work context. Thus, three indicators reflect the actual situation. The real-time tracking system is a useful tool for managing and evaluating field supervisor behavior in large hydraulic projects.
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    Rapid evaluation of anti-fouling coating materials for Limnopernafortunei
    YAO Guoyou, XU Mengzhen, AN Xuehui, WANG Zhaoyin
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 957-963.  
    Abstract   PDF (2163KB) ( 755 )
    Anti-fouling coatings are an efficient control method for the control of golden mussels. Rapid evaluation methods are needed to evaluate the effectiveness of anti-fouling coatings for screening. Forced attachment experiments were used to study the effectiveness of 17 types of commercially available coatings including polyurea, silane, and epoxy resins. The number of attached byssus, the attachment strength, and the contact angle on the materials were indicated by rapid evaluation indices for the coatings effectiveness. The results show that the average number of the attached byssus and the average attachment strength were negatively related to the contact angle on the materials, positively related to the dispersion force component of the surface free energy (Fowkes method), negatively related to the solid-liquid interfacial energy (ZDY method), and positively related to the solid surface free energy (ZDY method) of the coatings. Therefore, the contact angle, the dispersion force component of the surface free energy, the solid-liquid interfacial energy and the solid surface free energy were selected as the rapid evaluation indices for evaluating the effectiveness of the anti-fouling coatings. The indices provide scientific guidance for selecting anti-fouling coatings in large water transfer projects, such as the South-to-North Water Diversion Project.
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    Statistical features of the drainage network in the Qinghai-Tibet Plateau and the effect of the uplift
    LIU Le, WANG Zhaoyin, YU Guoan, LI Teng
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 964-970.  
    Abstract   PDF (3670KB) ( 847 )
    The continued uplift of the Qinghai-Tibet Plateau since the Late Cenozoic Era has not only tremendously influenced the plateau topography, but has also resulted in unique river networks in this area. The features of the stream networks and the influence of the plateau uplift on the river morphology were studied by measuring the number of streams, stream lengths, slopes and areas of the drainage basins for the Yalutsangpo, Jinsha, Yalong, Lancang, Nujiang, and upper Yellow River from shuttle radar topography mission (SRTM) data. The networks of the 6 rivers were mapped and analyzed by comparisons with the Horton Laws. The networks are represented by the Horton Laws for the streams from the first to sixth orders but deviate dramatically at the highest order. The results show that the plateau uplift is uniform in the inner part but the very different uplift speed at the plateau edge disrupts the stream networks.
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    CONSTRUCTION MANAGEMENT
    Effect of local governments' land leasing behavior based on yardstick competition
    LONG Fenjie, WANG Xiaomeng, ZOU Di
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 971-976,983.  
    Abstract   PDF (1503KB) ( 582 )
    This study theoretically and empirically analyzes how a yardstick competition influences a local governments' land leasing behavior spatially for a Chinese particular land supply system. The ratio of the industrial land to total land supply is shown to be affected by other governments'decisions due to yardstick competition from “top” and “bottom” when mobility factors are included through tests of the horizontal externalities in the land supply in 177 prefecture-level cities. The result shows spatial autocorrelation between local governments and their competitors who rank near them in terms of the ratio of the industrial and residential to total land supply because of the yardstick competition from the “top”, with of significance at 0.1 percent. For yardstick competition from the “bottom”, the coefficient of the spatial lag variable for residential land is no longer significant while industrial land maintains its ability to attract factors like labor and capital.
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    Relationship between diversification and performance of Chinese real estate listed companies
    ZHANG Hong, GAO Shuai, LI Vera
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 977-983.  
    Abstract   PDF (989KB) ( 658 )
    The existing research on the relationship between diversification and company performance still has many controversies. This study analyzes selected Chinese real estate listed companies as examples of company performance in an emerging capital market. The analysis considers the influence of regional diversification, product diversification, and business type diversification on the company performance using time series data (2007-2013). The factor analysis method is used to calculate a synthesize index to relate the degree of diversification and the performance. The results show no significant correlation between diversification and performance with regional diversification having minimal discount effect on the performance, product diversification having a secondary discount effect on the performance, and business diversification having the most significant discount effect on the performance. The combined effect of the diversification has a greater discount effect on the company performance.
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    Cyclical fluctuations of Beijing residential housing market based on a wavelet analysis
    FAN Ying, ZHANG Hong, YANG Zan
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 984-990.  
    Abstract   PDF (1732KB) ( 641 )
    This study analyzes the cyclical fluctuations of Beijing residential housing market using macro data in 1999-2014. This study uses a literature review to identify the limitations of current studies on real estate cycles and how to improve both the index selection and model simulations. The index selection uses objective weighting using a principal component analysis (PCA) to extract the core index and expand the sample data. The model simulation uses wavelet analyses to separate and rebuild the cyclical fluctuations. The empirical analysis shows a short 3.75 year short cycle and a medium 9 year cycle in Beijing residential housing market. The model indicates that the real estate market is entering a recession period in 2014, which will be noticed by market participants including investors, financial institutions and the government.
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    NUCLEAR AND NEW ENERGY ENGINEERING
    Modeling of the heat transfer characteristics of the effective thermal conductivity test facility for high temperature gas-cooled reactors
    REN Cheng, YANG Xingtuan, LI Congxin, SUN Yanfei, LIU Zhiyong
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 991-997.  
    Abstract   PDF (5027KB) ( 803 )
    The effective thermal conductivity is a characteristic parameter which represents the macroscopic heat transfer ability of the pebble bed type core of the high temperature gas-cooled reactor. A full-scale effective thermal conductivity measurement facility was developed by the Institute of Nuclear and New Energy Technology of Tsinghua University to improve calculations and safety analyses of the Chinese high temperature gas-cooled reactor design using experiments in a static graphite pebble bed in a vacuum or helium environment. A simplified two-dimensional model was used to simulate the thermal conduction and radiation characteristics of the facility under vacuum and at high temperatures. The steady and transient heat transfer characteristics were calculated to assess the radial temperature distribution in the pebble bed zone, the influences of different materials in the top and bottom insulating layers, overheating of the central heaters and temperature increases and decreases to guide operation of the experimental facility.
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    Optimization of the high temperature tensile strength design method for the GH3128 Alloy
    ZHAO Xi, YUAN Kun, ZHOU Yu
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 998-1002.  
    Abstract   PDF (1825KB) ( 628 )
    GH3128, a domestic Ni-based superalloy, has good high-temperature performance and is a promising main structural material for intermediate heat exchangers (IHX) which are the key component in very high temperature reactors (VHTR). The existing American Society of Mechanical Engineers (ASME) standard is shown to be inappropriate. Then, 3 fitting methods (single polynomial fit, 2-step polynomial fit and 2-step exponential fit) are used to calculate the allowable design strengths for the tensile strength. The results show that the 2-step polynomial fit method should be used for the ultimate tensile strength with the 2-step exponential fit method for the yield strength. These design curves give consistent and reliable design margins for the structural design of IHX.
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    Fast boundary element method based on a 3D pipe model for analyzing cathodic protection
    LIU Liqi, WANG Haitao
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 1003-1009.  
    Abstract   PDF (1938KB) ( 600 )
    The boundary element method (BEM) was used to analyze a cathodic protection (CP) system consisting of large pipeline structures. A three-dimensional pipe boundary element model was used to reduce the number of elements on the pipelines as well as the element integral computations. The pipelines were meshed with line elements with the boundary integrals were based on the original shapes. The large-scale CP problem was solved on a common desktop computer using the fast multipole method (FMM) to accelerate the BEM. The nonlinearity introduced by the polarization curve at the cathode was solved iteratively. The numerical results demonstrate that the number of elements can be reduced by one order of magnitude when discretizing pipelines with these line elements compared with triangular elements and that the FMM can solve large CP problems with up to 50 000 dimension of freedoms (DOFs).
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    HTR-10GT inventory control characteristics and mechanism
    LI Xiao, YANG Xiaoyong, ZHANG Youjie
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 1010-1016,1022.  
    Abstract   PDF (2256KB) ( 556 )
    The HTR-10GT inventory control characteristics were analyzed to design a system with low recuperated effectiveness. The system was modeled using a simplified model based on reasonable hypotheses and numerical simulations of the entire system model. The results illustrate that the helium mass flow rate decreases as the load decreases but at a slower rate with both following approximately quadratic relations. The regenerator effectiveness is improved which improves the cycle efficiency; however, the efficiency is reduced by temperature ratio decreases, several components deviating from their design operating points and Reynolds number effects. The Reynolds number effects also negatively impact the compressor stability. This study provides reference information for high temperature gas-cooled reactor (HTR) cycle design and operation.
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    ENVIRONMENTAL SCIENCE AND ENGINEERING
    Strategic game model for climate change negotiations based on utility theory
    WANG Can, JIN Zhugang, CAI Wenjia
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 1017-1022.  
    Abstract   PDF (1125KB) ( 982 )
    A game theory model incorporating utility theory was used to analyze climate change strategies for different countries. The model includes the positive, negative and spillover effects of climate change related investments, temperature change uncertainties and their effects on GDP (gross domestic product) growth. The strategies are dynamic to test for the existence of the first-mover disadvantage. The first-mover disadvantage hypothesis is also confirmed by a typical real case. The strategic model indicates that each country should wait and urge others to make promises in advance, as has been seen in real negotiations.
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    Technical-economic analyses and prediction of liquid biofuels in China
    ZHAO Lili, CHANG Shiyan, XU Jie, ZHANG Xiliang
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 1023-1035.  
    Abstract   PDF (2162KB) ( 667 )
    A plant-gate price (PGP) estimation model was used in technical-economic analyses of 17 liquid biofuel production processes. The net present value (NPV) method was used to determine the PGPs of biofuels with a finite internal rate of return based on the costs for total investment, feedstock, operation, taxes, fees, and loans. The results will help policy makers formulate incentive policies for research and development (R&D) of liquid biofuels in China. The results indicate that the PGPs of 1.5th generation biofuel products are highly sensitive to feedstock cost (54%-90%). Bioethanol based on non-grain starches and sugars, and biofuels based on jatropha will be competitive with fossil fuels by 2020-2025. Most of 2nd generation biofuel PGPs will drop during 2020-2030 and will be competitive with fossil fuels around 2025. The feedstock cost, 13%-40%, and operating expenses, 21%-48%, contribute almost equally to the PGPs. In the mid-and long-terms, the priorities should be to develop 2nd generation fuels. The PGP of 3rd generation biofuels are the most sensitive to the feedstock cost (64%-96%) and will not be able to compete with fossil fuels until 2040-2045. Tax preferences will be critical to accelerating the growth of biofuels. Most biofuels will be competitive with fossil fuels 10-15 years earlier if the value-added tax (VAT), consumption tax and income tax are exempted. They will be competitive with fossil fuels even earlier as if a carbon tax is imposed on fossil fuels. However, the effect of the carbon tax will not be significant in the near-and mid-terms. This research suggests that the government develops a long-term plan and take action towards the sound development of biofuels by promoting feedstock breeding, helping establish a cost-effective feedstock collection, storage and transportation system, and support R&D and demonstration projects of biofuel conversion technologies. Policies including tax preference and carbon tax are also suggested to accelerate the biofuel development.
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    BIOLOGICAL SCIENCE AND ENGINEERING
    Fast CAPs threshold and tuning curves based on a sound card detection system
    GONG Qin, ZHANG Shuoyue
    Journal of Tsinghua University(Science and Technology). 2015, 55 (9): 1036-1044.  
    Abstract   PDF (1751KB) ( 524 )
    Auditory nerve compound action potentials (CAPs) threshold curves reflect the hearing sensitivity to intensity variations while its tuning curves reflect the sensitivity to frequency variations in the auditory nerve system. A fast CAPs threshold and tuning curve detection algorithm were developed based on an external multimedia sound card with C# to simplify the data extraction for studies of the auditory nerve system with more objective and more accurate information in a shorter time. The factors influencing the fast CAPs tuning curves such as the orientation of the sweeping frequency and the frequency of the stimulus were analyzed using guinea pig experiments. The fast CAPs threshold and tuning curves compare well with previous results. The factors contributing to fast CAPs tuning curve accuracy include reduction of the needed criteria and the rates of change for the masker intensity. This system is a fast, objective, and comprehensive analysis platform which will be valuable for further research on auditory nerve compound action potentials.
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