WEI Kai , GONG Quanmei , ZHOU Shunhua
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.001 CSTR:
Abstract:The corresponding relationship between long term uneven settlement law of Shanghai Metro shield tunnel in operation period and the idea of ant colony algorithms is found based on the measured settlement data.Then a new prediction model of long term uneven settlement in tunnel is put forward on the basis of colony algorithms.The forecasting effect of the new model is tested.A comparative study is made of predicted data with the measured data,and the idea of establishing and perfecting the new model is acquired.The results show the prediction model is directly established on real settlement data,which avoids the mistakes due to factitiousness in traditional methods.The established prediction model proves to be accurate,easy to operate and adaptable.Besides,the model can be improved in many fields,which fact is considered as a brand new way to long term uneven settlement prediction calculation of tunnel.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.002 CSTR:
Abstract:Basic thought and contents of performance based antiterrorism design for bridges are discussed,including the relationship between the antiterrorism fortification level and antiterrorism performance of bridges,the determination of antiterrorism performance grades for bridges and the objective of antiterrorism performance.The concept of the multi layered defense is proposed.This paper presents a general framework of bridges’ antiterrorism design comprising three design phases and six design processes.
PENG Wei , PENG Tianbo , LI Jianzhong
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.003 CSTR:
Abstract:In order to find out the appropriate longitudinal seismic constraint system for multispan cable stayed bridge,an analysis is made of the dynamic characteristics and linear seismic response of the bridge under four kinds of rigid constraint systems between girder and different pylons in longitudinal direction based on a cable stayed bridge with six pylons in China.The results indicate that,for a multispan cable stayed bridge,only changing the positions of rigid constraints,the partial pylons constraint system is not appropriate for seismic performance; the system with all the pylons being constrained by girder or the total floating system can diminish the difference of seismic response of different pylons,but when multispan cable stayed bridges with total floating system are used in soft soil condition,special attention must be paid to the seismic design of side pylon and structural longitudinal displacement.
ZENG Yong , CHEN Airong , MA Rujin
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.004 CSTR:
Abstract:A practical normalized stress intensity factor is stated in this paper on the basis of the evolution of cracks of cable wires, which fits the crack growth behavior for a semicircular crack and for straight crack. Example testifies that the fracture strength of a cable wire with a surface crack can be assessed conveniently and the result can be acquired with satisfactory precision by this convenient and practical method. And the fracture toughness criterion is more realistic for the fracture strength of the wire.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.005 CSTR:
Abstract:The protection current distribution was investigated in a three layer reinforced concrete cathodic protection system, with carbon fiber reinforced cement based material as the conductive coating anode. The influence of steel bars’ initial current state, concrete resistivity and magnitude of applied current density on the current distribution was discussed, respectively. The results show that both the initial corrosion rate of rebars and concrete resistivity have a great effect on the protection current distribution. However, the magnitude of impressed current density only affects the uniformity of current distribution to some extent when the rebars are corroding severely. This study contributes to the cathodic protection of reinforced concrete structures in field condition.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.006 CSTR:
Abstract:Experiment of 23 materials under similar lighting condition show that the physical illuminations of different construction materials have widely discrepancy. Lighting level is decided by reflectance,and the illustriousness changes with various angles of incidence and viewing.Consideration of other impact factors, modified coefficient K obtained from experimental values amends the computing formula recommended by the International Commission on Illumination(CIE),and then a new formula is derived.Compared with the original computing formula,an effective energy saving is achieved.
JIANG Jinyong , YUN Meiping , YANG Peikun
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.007 CSTR:
Abstract:The paper presents a set of equations to estimate optimal cycle lengths for signalized intersections based on the delay models of Highway Capacity Manual 2000.Firstly,theoretic methods to calculate the optimal cycle length with minimum delays are proposed.Then optimal cycle lengths for sample intersections representing typical traffic situation scenarios are calculated.Two equations to estimate the optimal cycle length are developed respectively for two phase and multi phase signalized intersections through regression analysis.The new equations overcome the shortcomings of the famous Webster cycle length equation which is not applicable to intersections with high degrees of saturation.
XU Tiandong , SUN Lijun , HAO Yuan , DU Yuchuan
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.008 CSTR:
Abstract:In order to guide traffic in road network level, to equilibrate traffic distribution and improve traffic efficiency in a macroscopic level, the paper presents a study of the drivers’ dynamic route choice according to the varying traffic information provided by variable message signs(VMS) of advanced traveler information system(ATIS) in a typical urban road network. For a VMS with only literal information set on surface street, and a VMS with both literal and graphic information set on urban freeway, State Preference(SP) survey is carried out to investigate traffic behavior data, which are then analyzed by disaggregate choice behavior method. A dynamic route choice behavior model is founded, which is suited for situations when travel time, traffic conditions, and information of traffic incidents of different routes are known. Results show that the veracity and integrality, and the personal characteristics of drivers are main factors to impact the route choice behavior. The study provides a basis for founding ATIS and setting optimal strategies of information promulgation.
WU Jiaorong , FENG Jiandong , CHEN Xiaohong
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.009 CSTR:
Abstract:Based on a comparative study of the fire emergency evacuation design specified in China’s current “Subway Design Specifications” and “NFPA 130 Standard for Fixed Guideway Transit and Passenger Rail Systems2007 Edition” by National Fire Proteciton Association,deficiencies of“Subway Design Specifications”are revealed.The escalator capacity is expected to be too large,and walking speed of passengers by means of evacuation facility is not well defined.In addition,the evacuation design is not well specified.Finally,the paper presents some proposals for improving “Subway Design Specifications” of China.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.010 CSTR:
Abstract:A study was made of the mechanical properties of ordinary Portland cement modified asphalt emulsion concrete,including compressive strength and compressive modulus,flexural strength and flexural modulus.Bases on infrared spectroscopy analysis,X ray diffraction analysis and scan electron microscopy,an investigation was made into the microstructure characteristics of cement asphalt emulsion mastic and concrete interface.The results show that all mechanical properties of asphalt emulsion concrete improve significantly,when the cement increases.There is no obvious chemical reaction between cement and asphalt emulsion in cement asphalt emulsion mastic,and cement can hydrate with the watery phase of asphalt emlusion.The hydrate products of cement in asphalt emulsion are similar to those in water.The cement asphalt mastic,which is physical compoud mastic by netlike hydrate products and asphalt,improves the adherence of binder aggregation and mechanical properties of asphalt emulsion concrete.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.011 CSTR:
Abstract:The traditional method was modified and applied to the assessment of the eutrophication of China lakes.Five indicators such as chlorophyll a (Chl.a),total phosphorus (TP),total nitrogen (TN),chemical oxygen demand (COD),and secchi disk depth (SD) were included,and each one was assigned with a weight.The method was validated by the measured data of 27 lakes in China and also compared with the other assessment methods.The results show that the method is easy to calculate but obtains convincing conclusions.The method is a valuable tool for lake management in China.
YANG Jian , ZHAO Limin , CHEN Qiaoyan , YI Danghao
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.012 CSTR:
Abstract:Ecological and physiological adaptabilities of earthworms in vermifilter were studied under different hydraulic loading,and physiological indexes of earthworms in different filter conditions were compared with that of artificial cultured earthworm with the same natural influencing factors.The results show that when hydraulic loading rises from 2.4 m3·m-2·d-1 to 6.0 m3·m-2·d-1,density and biomass in unit area of earthworms are affected by hydraulic loading slightly.Though,the two items take on a trend of slowly decrease,they can keep a level of 1.5×104·m-2 and 3 kg·m-2 separately and the filter’s environment is favorable for earthworms to breed and hatch.While compared with artificial cultured earthworms,food taken,digestion,excretion and other ecological functions are brought to excellent play in the case of this loading.What’s more,the digestibility reaches to 35.31%~41.47% which is markedly prior to that (17.17%~25.95%)of earthworms in cow dung.However,when the hydraulic loading increases up to 6.7 m3·m-2·d-1,earthworm number and bio quantity reduces 1/3 and respiratory system function has a notable decrease which is notably lower than that of artificial cultured earthworms,furthermore, metabolism level of sludge is influenced.In order to maintain a good living environment for earthworms to assure the exertion of ecological function,it is commended that the running hydraulic loading in earthworm vermifilter should not exceed 6.7 m3·m-2·d-1.
LI Yongmei , YANG Shijia , ZENG Qingling , GU Guowei
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.013 CSTR:
Abstract:Lab scale experiments were conducted to investigate the degradation potential of 17β estradiol (E2) and 17α ethinyl estradiol (EE2) by anaerobic anoxic oxic (A2O) activated sludge process.Based on the removal of nutrients and estrogen,the operational parameters such as hydraulic retention time (HRT),sludge retention time (SRT) and the recycle ratio of mixed liquor (r) were optimized.The results indicate that estrogens are dramatically removed by the A2O process.At the fixed temperature of 20℃ and sludge recycle ratio of 100%,the optimum operational parameters for HRT,SRT and r are 8 h,20 d and 300%,respectively.Under the above optimum conditions,the removal efficiencies of TN,PO3-4-P and COD are 82%,95% and 84%,respectively.E2 in the final effluent is below the detection limit; of the totally removed E2,72%,6% and 22% are removed in the anaerobic,anoxic and oxic tanks,respectively.EE2 removal efficiency is more than 80%; the anaerobic,anoxic and aerobic tanks contribute 45%,21% and 34% of the totally removed EE2,respectively.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.014 CSTR:
Abstract:Speech articulation is the key point of research on classroom acoustics,and speech articulation testing is the most direct approach to decide whether the listening environments are superior or inferior.It is sometimes very difficult to find the required classrooms where factors of listening environment can be regularly changed.Virtual listening environment where reverberation time can be regularly changed can be fabricated by applying exponent attenuation to the signal of actural classroom,so does signal to noise ratio by intermingling noise with the dead signal obtained in anechoic room.Speech articulation tests were done in those virtual listening environments,and then the optimal reverberation time in mid frequencies and minimal signal to noise ratio can be obtained by analyzing the variance of articulation index scores.Results prove that research on speech articulation in classrooms by fabricating virtual listening environment is applicable.
NING Guobao , WANG Yongzhan , YU Zhuoping , CHEN Xinbo
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.015 CSTR:
Abstract:According to a in wheel motor driving electric vehicle assemblied with double wishbone suspension with torsion bar,the mathematic model of suspension is built,in which the structure features,the dimensions and the gestures of the bars,the springs and the dampers are considered.With the mathematic model of the suspension,the 1/4 vehicle model is also built.Based on this model,the structural nonlinearity is researched,and the vehicle performances especially vertical performances are discussed considering the structural nonlinearity.This research method brings the suspension damping and stiffness match into nonlinear field,which advances the deactive suspension development theory.
ZHU Shaozhong , GAO Xiaojie , YU Zhuoping
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.016 CSTR:
Abstract:Through linearizing nonlinear vehicle model,vehicle side slip angle estimation algorithms based on generalized Kalman filter and generalized Luenberger observer are formulated.An extended 2 degree freedom vehicle model considering tire nonlinear characteristics is firstly proposed,and the tire model parameters are obtained with nonlinear least square method.Through local linearization method,the nonlinear vehicle model is linearized at current working states and by using this linear vehicle model,generalized Kalman filter and generalized Luenberger observer for side slip angle estimation can be developed.Finally the effectiveness of both algorithms is verified through different handling maneuvers.Under extreme driving situation,the proposed methods can provide much higher estimation precision.
CAO Jing , LI Liguang , SUN Yongzheng , LIU Yaqi
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.017 CSTR:
Abstract:Through theoretical calculations,the study takes the city Shanghai as an example to analyze the effect of fuel saving and substitution if taxis,buses in public transport and private cars employ hybrid electric and fuel cell technologies,which provides a basis for dramatically cutting down the energy consumption of the public transportation to realize the aim of the next “eleventh five year plan”.
MA Jun , WANG Ning , KONG Deyang
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.018 CSTR:
Abstract:According to China consumer purchase behavior and utility maximum, AHP method is used to analyze the weight of each main decision factors such as cost, reliability, dynamic performance, image, safety and conveniences. China NEV market share forecasting model is established based on logit regression analysis between USA, Europe and Japan NEV market share and customer utility. The forecasting model studies three different government regulation scenarios: basic scenario, general scenario and radical scenario. The results of the model indicate that government regulations have obvious impact on NEV market performance. In 2015, NEV is expected to account for 14% market share under basic scenario, 23% under general scenario and 36% under radical scenario. Hybrid Energy Vehicle and Battery Energy Vehicle take account of the biggest market share under three scenarios, Fuel Cell Vehicle accounts for the least market share through 0.25% to 0.85% under the three scenarios.
ZHOU Jinsong , GONG Dao , REN Lihui
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.019 CSTR:
Abstract:To suppress the vibration of flexible carbody of railway vehicle,flexible damper is proposed to be longitudinally installed under carbody underframe.Taking the carbody as a uniform Euler beam supported on secondary suspension,including the structure damping ratio and the flexible damper,a vertical model was built to research the effects of flexible damper on the vehicle ride quality by using the fast ride quality calculation algorithm.The results show flexible damper can help control the flexural vibration of the flexible carbody and the higher the flexible carbody damping coefficient,the lower the first bending frequency of carbody need to be.Researches also show that the nearer the carbody damper installation position is to the center of the carbody,the better effects it will achieve.An example is illustrated in the paper.When the coefficient of flexible damper reaches to 5.0× 109 N·s·m-1,the required lowest bending frequency will drop to 6.5 Hz,which can still achieve good ride quality under 200 km·h-1 operational speed.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.020 CSTR:
Abstract:The technical risk (Rt) management is dynamically fulfilled throughout and matched with the development process, from the upper layers to lower ones.The Rt is defined in the view of analyzing and controling it during the product development.Two dimension model of Rt is put forward which consists of Rprd (technical risk of product) and Rprs (technical risk of process).Hereby the technical risk management system of complex product development is set up.There are identification and assessment of Rt, risk planning,tracking and controlling on function layer,Rt management is processed on system,subsystem,manufacturing level on process layer.Rt management system is applied to the development of lithgraphy machine.
TANG Yanbo , GE Wancheng , GONG Guoqiang
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.021 CSTR:
Abstract:Conventional maximum likelihood algorithm based on cyclic prefix has plateau effect and has no obvious peak correlation value in multi path channels,because some of the cyclic prefixes have been polluted by Inter Symbol Interference(ISI)due to the multi path delays and Doppler effects.The algorithm can not be used in multi path channels without optimization.An optimized method based on the cyclic prefixes is proposed in this paper,which reduces the number of cyclic prefixes in correlation calculation according to the signal noise ratio and multi path delays and uses average correlation values in multi sampling points.The proposed method proves to be able to get sharp peak values and improve the symbol precision compared with the existing methods both in Additive white Gaussian noise(AWGN) channels and in multi path channels.In multi path channel,plateau effect decreases significantly.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.022 CSTR:
Abstract:According to a simulated data set,single epoch positioning results by kinematic positioning were obtained,and then the attitude were calculated with various antenna combinations respectively.The results show that when the length of the baseline is about 5m in square,the RMS for Yaw is about ±0.05°,while Roll and Pitch are about ±0.2°.When the length of the baselines is about 10m in square,the RMS for Yaw is about ±0.03°,while Roll and Pitch are about ±0.11°.So the accuracy of the attitude angles has a correlation with the length of the transverse and longitudinal baselines.When the lengths of baselines are the same,the accuracy of Yaw is higher than Roll and Pitch.The accuracy of Yaw and Roll mainly depends on the lengths of the longitudinal baselines,while the accuracy of Pitch transverse denpends on the length of transverse baselines.In general,the longer the baseline is,the higher accuracy of the attitude angles will be.
SHI Yimin , CHEN Wei , SHI Baoxiang
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.023 CSTR:
Abstract:A new method of transformation between the three dimension geocentric coordinate system and independent coordinate system in adjustment of GPS networks is proposed.Compared with the conventional methods,it is not based on the 54 or 80 national reference ellipsoid.In the present technical situation,it’s easy to get the accurate geocentric coordinates on all control points with GPS.In order to transform the coordinates to the existent independent coordinate system exactly and conveniently,the regional ellipsoid surface approximated to the projection plane is firstly adopted in this mode,and then transformation is realized on Gauss plane.This method not only realizes the accurate transformation between the two coordinate systems,but also provides a complete set of transformation parameters for the whole area for a long period.Analogously it provides also a new simple method which can generate the transformation parameters with 3 known points in the smaller area.
LIU Feng , CAI Jingong , LV Bingquan , GAO Xianzhi
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.024 CSTR:
Abstract:The comprehensive analysis of geochemistry and petroleum geology is used to study petroleum source and accumulation characters of Archean metamorphic buried hill of Xinglongtai in the west Sag of Liaohe Depression.The results show that the oil gas reservoir sequence of the buried hill can be divided into two systems of oil pool formation.One is the high pressure system near the top of the buried hill,the other is the normal pressure system in the inner of the buried hill.The crude oils from two systems have similar geochemical characters,which is characterized by the concentrations of saturated hydrocarbons more than 75 percent,low isoprenoid alkane contents,Pr/Ph around 1.0,paucity of gammacerane,C27,C28,C29 sterane distributed in”V” shape.They are the highest maturity oils of Xinglongtai and both from the highly mature source rocks of Es3 in Qingshui Subsag.Reservoring period of two systems is very close,however,two systems are distinctly different in system of migration passage and main factors controlling hydrocarbon accumulation.Reservoir forming mode of the buried hill can be characterized by the unidirectional oil gas source,multiple transportation system(unconformity,fault and fissure in the buried hill),bidirectional migration(lateral migration and vertical migration),multi period accumulation.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.025 CSTR:
Abstract:The study of the relationship between the design parameters and the cost is helpful to the designers to consider the economics of the project.The system of the relationship between the design parameters and the cost is semi quantitative analyzed through the interpretative structral modelling method(ISM),and the structure of the system is set up.Changes of the design parameters will affect much the cost of the building.The higher the level of the parameter is,the more the influence is.The building size,storey height,numeber of storeies,building shape,total height of the building are the main cost drivers.Taking the residential building as an example,the cost estimating model with the regression model at the foudation of the result of the ISM application is set up.The “ISM+regression model” is a useful method to study to which degree changes in the parameters of the building will affect the cost of that building,and aslo it’s helpful for the quantitative analysis to the relationship between the building parameters and cost.
WANG Xia , HUANG Xianjin , ZHEN Feng , ZHONG Taiyang
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.026 CSTR:
Abstract:The evaluation information of development potential of urban underground space resource is not complete and exact entirely.The multi level grey approach is employed to develop the evaluation index system of development potential of urban underground space resource.A case study is made of the five main blocks in Gulou district of Nanjing.The result shows that the multi level grey evaluation on the development potential of urban underground space resource doesn’t require a large sample,but offers an effective reference for the scientific and normative evaluation on the development potential of urban underground space resource.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.027 CSTR:
Abstract:Based on convenient sample and questionnaire survey,an analysis is made of the corporate political strategies and its effectiveness for foreign firms in Shanghai.The study shows that corporate political strategies are paid much attention to and implemented well by foreign firms in Shanghai.Firm level factor and managers’ individual personal level factors influence prominently the corporate political strategies.Big firms are more likely to take active political strategies.Managers with longer working years tend to keep closer relationship with government.Managers’ education level is negatively related in this regard.Three generic political strategies (information,financial incentive and constituency building) proposed by Hillman and Hitt are believed to be effective strategies among foreign firms.
2009, 37(8). DOI: 10.3969/j.issn.0253-374x.2009.08.028 CSTR:
Abstract:To diversify credit risk,the so called deposit linking with credit risk is issued,whose return depends on whether a specified firm default before the maturity of the deposit.The first passage model is employed.A firm is believed to go bankrupcy when its assets are less than its debts.With stochastic interest rate,the closed form pricing formula is obtained with partial deffrential equation approach.Finally,the financial significance is discussed.
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