既有线PCT梁的改造及快速列车作用下的走行性分析

本文针对我国既有线上混凝土T梁在客、货车提速下难以满足要求的问题 ,提出了既有线PCT梁的改造方案并应用MSC/PATRAN、MSC/NASTRAN、MSC/DYTRAN大型结构分析程序进行了桥梁动力特性及一动六拖电动车组速度为 14 0km·h- 1 ～ 3 0 0km·h- 1 时的走行性分析 ,结果表明本文提出的加固方案大大提高了桥梁的有载频率 ,避免了桥梁在货车作用下的横向谐振 ;同时桥梁的动力特性及车辆的运行安全性和平稳性满足速度小于 2 2 0km·h- 1 的一动六拖电动车组的运行。

高速铁路多Π形预应力混凝土梁桥动力特性及列车走行性分析

提出了高速铁路多Π形预应力混凝土梁桥空间振动分析模型及列车－多Π形梁桥时变系统空间振动方程的建立方法，用它可简便分析跨宽比很小的多Π形梁桥与列车系统的空间振动，亦可用于一般单Π形梁桥考虑畸变与翘曲的静、动力分析。实例分析结果证明本文提出的模型和方法能良好地反映列车与桥梁系统的实际空间振动行为。

高墩大跨连续刚构桥动力特性分析

本文运用桥梁结构动力学与车辆动力学的研究方法,建立车桥时变系统空间振动方程。对某高墩大跨连续刚构桥进行了列车走行性分析,得出在列车作用下的车桥动力响应的理论计算结果,表明该桥具有足够的横竖向刚度,能够保障列车行车的走行安全性与乘坐舒适性的要求。同时根据计算结果可以得出在高墩大跨预应力混凝土连续刚构桥中,边墩或边跨出现最大响应的可能性非常大,因此在高墩大跨预应力混凝土连续刚构桥设计中对边墩的考虑应予以足够重视。

Development of engineered cementitious composites with local ingredients

In order to reduce the cost of high performance polyvinyl alcohol（PVA） fiber reinforced cementitious material（called engineered cementitious composites,ECC）,a ductile ECC material is developed using domestic PVA fibers along with other local ingredients,such as fly ash,cement and sand.In addition to the economic analysis of ECC,the four-point bending test and the optical microscope are employed to investigate the deflection capacity of ECC,its crack width and the occurrence of the self-healing phenomenon.The experimental results suggest that ECC made with domestic ingredients exhibits larger deformability and the average crack width is controlled around 60 μm.Furthermore,the self-healing behavior is observed in cracks of the specimens after cycles of wet and dry curing.The economic analysis shows that the cost of ECC can be greatly reduced via employing domestic PVA fibers.It is,therefore,feasible to produce low cost ECC material employing domestic PVA fibers,while simultaneously retaining high material ductility.

Bus transit travel time reliability evaluation based on automatic vehicle location data

In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed and evaluated based on automatic vehicle location （AVL） data. Based on the statistical analysis of the bus transit travel time, six indices including the coefficient of variance, the width of travel time distribution, the mean commercial speed, the congestion frequency, the planning time index and the buffer time index are proposed. Moreover, a framework for evaluating bus transit travel time reliability is constructed. Finally, a case study on a certain bus route in Suzhou is conducted. Results show that the proposed evaluation index system is simple and intuitive, and it can effectively reflect the efficiency and stability of bus operations. And a distinguishing feature of bus transit travel time reliability is the temporal pattern. It varies across different time periods.

Variation of the second-phase morphology and its influence on fracture behavior of Al-Si alloy

Using an optical microscope and scanning electron microscope (SEM), the variation of eutectic Si morphology of Al-Si alloy in solution treatment was observed to study its influence on mechanical properties and fracture behavior. The results show that eutectic Si undergoes stubbing, necking, fragmentation, and growth in the initial stage (250 min); in the middle solution stage (250 to 400 min), the eutectic Si morphology has no significant change, only the degree of spheroidizing becomes higher; after 600 min, the growth of eutectic Si is a coarsening process controlled by diffusion and follows the Liftshitz-Slyozov-Wangner (LSW) model, and the eutectic Si morphology deteriorates due to the occurrence of facets and lap. Based on the quantitative measure and regression analysis, the eutectic Si morphology has a remarkable influence on mechanical properties and fracture behavior.

Influence of land use characteristics and trip attributes on commuting mode choice: a case of Nanjing

The effects of socio-demographics, land use characteristics and trip attributes on the commute mode choice are studied with a nested logit （NL） model. Based on the random utility maximum theory, the NL model is formulated. The analysis is carried out in the main area of Nanjing. Direct and cross elasticities are calculated to analyze the effects of travel time and travel cost on the selection of travel mode choice. The results reveal that the non-motorized travel modes are more attractive in the areas with higher housing and employment accessibility and car owners are found to be more likely to commute to work by car. The bus and subway choice probabilities are more sensitive to changes in travel times than to changes in travel costs. In conclusion, a comprehensive public transit system and effective integration of land use and transportation policies help to relieve the traffic congestion levels caused by the increasing urban sprawl.

循环流化床机组超深度调峰20%额定负荷方式探讨

随着电网容量的不断增容,光伏、风电、水电等新能源发电容量在电网中的比例逐渐增大,600MW、1000MW大容量火电机组并入电网台数的增多、原电网中的火电机组作为调峰幅度的增大、“碳达峰、碳中和”即“双碳目标”时限的不断趋近,尽管电网火电机组深度调峰幅度要求越来越宽,但低谷期间电网度过深谷点仍很困难,这样对各火电机组调峰的深度挖潜再度提出更高要求,力求最大限度地满足电网的需求。

Relationship between number of passing events and operating parameters in mixed bicycle traffic

This paper investigates the passing events between electric bicycles and conventional bicycles and explores the relationships between passing events and traffic parameters in bicycle facilities.Three exclusive bicycle paths in Nanjing, China,were observed with cameras.Then,the field data including vehicle number,velocity characteristics and passing event features were analyzed in detail.Data analysis and fitting reveal that the speed difference has little impact on the passing event number,as does the bicycle ratio.The Gaussian function can better describe the relationship between the passing event number and bicycle volume （density）.The valid use level of bicycle path width influences the inflexion of the passing events-density fitting curve.The conclusions can be applied for estimating the passing events in mixed bicycle flows and for choosing a suitable width of separate bicycle path.

EFFICIENT METHOD FOR MULTIDISCIPLINARY DESIGN OPTIMIZATION BY CONSIDERING UNCERTAINTY

A new reliability-based multidisciplinary design optimization （RBMDO） framework is proposed by combining the single-loop-based reliability analysis （SLBRA） method with multidisciplinary feasible （MDF） method. The Kriging approximate model with updating is introduced to reduce the computational cost of MDF caused by the complex structure. The computational efficiency is remarkably improved as the lack of iterative process during reliability analysis. Special attention is paid to a turbine blade design optimization by adopting the proposed method. Results show that the method is much more efficient than the commonly used double-loop based RBMDO method. It is feasible and efficient to apply the method to the engineering design.

Feasibility and safety of autologous bone marrow mononuclear cell transplantation in patients with advanced chronic liver disease

AIM： To evaluate the safety and feasibility of bone marrow cell （BMC） transplantation in patients with chronic liver disease on the waiting list for liver transplantation. METHODS： Ten patients （eight males） with chronic liver disease were enrolled to receive infusion of autologous bone marrow-derived cells. Seven patients were classified as Child-Pugh B and three as Child-Pugh C. Baseline assessment included complete clinical and laboratory evaluation and abdominal MRI. Approximately 50 mL of bone marrow aspirate was prepared by centrifugation in a ficoll-hypaque gradient. At least of 100 millions of mononuclear-enriched BMCs were infused into the hepatic artery using the routine technique for arterial chemoembolization for liver tumors. Patients were followed up for adverse events up to 4 mo. RESULTS： The median age of the patients was 52 years （range 24-70 years）. All patients were discharged 48 h after BMC infusion. Two patients complained ofmild pain at the bone marrow needle puncture site. No other complications or specific side effects related to the procedure were observed. Bilirubin levels were lower at 1 （2.19 ± 0.9） and 4 mo （2.10 ± 1.0） after cell transplantation that baseline levels （238 ± 1.2）. Albumin levels 4 mo after BMC infusion （3.73 ± 0.5） were higher than baseline levels （3.47 ± 0.5）. International normalized ratio （INR） decreased from 1.48 （SD = 0.23） to 1.43 （SD = 0.23） one month after cell transplantation. CONCLUSION： BMC infusion into hepatic artery of patients with advanced chronic liver disease is safe and feasible. In addition, a decrease in mean serum bilirubin and INR levels and an increase in albumin levels are observed. Our data warrant further studies in order to evaluate the effect of BMC transplantation in patients with advanced chronic liver disease.

Planning method for AUV region detection under ocean current

In this paper we present two strategies of AUV (Autonomous Underwater Vehicle) region detection and an approach to decompose the detection region according to the direction of the ocean current. In the task of local detection and identification, the algorithm against the ocean current was proposed. In the tasks of closing obstacle, going back or moving, the fuzzy logic theory was used to solve the effect of ocean current. In one of our strategies the concept of weighted journey based on the angle between heading and ocean current is suggested and the TSP's exact optimal result is utilized to solve the global path planning. Simulations demonstrate the feasibility of this approach.

A DSS DEVELOPMENT AND APPLICATION FOR SUSTAINABLE DEVELOPMENT

The characteristics of sustainable development problems in the developing countries is discussed.In order to develop and use decision support system (DSS) for supporting sustainable development problem decision making in the developing countries,this paper presents a strategy of constructing the DSS for sustainable development.A methodology of representing the model of sustainable development problems and developing a nonprocedural modeling language that is used to define sustainable development problems,a methodology of numeric and non numeric operation based theorem proving is given in this paper.

Discontinuous flying particle swarm optimization algorithm and its application to slope stability analysis

A new version of particle swarm optimization(PSO) called discontinuous flying particle swarm optimization(DFPSO) was proposed,where not all of the particles refreshed their positions and velocities during each iteration step and the probability of each particle in refreshing its position and velocity was dependent on its objective function value.The effect of population size on the results was investigated.The results obtained by DFPSO have an average difference of 6% compared with those by PSO,whereas DFPSO consumes much less evaluations of objective function than PSO does.

Development of dynamic-mathematical model of hydraulic excavator

This work deals with analysis of dynamic behaviour of hydraulic excavator on the basis of developed dynamic-mathematical model.The mathematical model with maximum five degrees of freedom is extended by new generalized coordinate which represents rotation around transversal main central axis of inertia of undercarriage.The excavator is described by a system of six nonlinear,nonhomogenous differential equations of the second kind.Numerical analysis of the differential equations has been done for BTH-600 hydraulic excavator with moving mechanism with pneumatic wheels.

Preliminary Study on Applicability of Microsatellite DNA Primers from Parasite Protozoa Trypanosoma cruzi in Free-living Protozoa

In this paper, we took the lead in studying on specificity of the microsatellite DNA loci and applicability of mi crosatellite DNA primers in protozoa. In order to study characters of microsatellites in free living protozoa, eight microsatellite loci primers developed from Trypanosoma cruzi (MCLE01, SCLE10, MCLE08, SCLE11, MCLF10, MCLG10, MCL03, MCL05) were employed to amplify microsatellite in four free living protozoa, including Bodo designis, Euglena gracilis FACHB848, Paramecium bruzise and Tetrahymena thermophila BF1. In the amplification systems of P. bruzise, four loci (SCLE10, SCLE11, MCLF10, MCL03) were amplified successfully, and four amplification fragments were in proper size. In genome of E. gracilis FACHB848, five of eight primers brought five clear amplification bands. In B. designis, three (No.4, 5 and 7) of eight loci produced clear and sharp products without stutter bands, whereas no bands appeared in T. thermophila BF1. Further, eight 300-500 bp amplification fragments were cloned and sequenced. Nevertheless, all sequenced products did not contain corresponding microsatellite sequence, although Bodo is in the same order and has the nearest phylogenetic relation with Trypanosoma among these four species. Thus, the microsatellite DNA primers can not be applied among order or more far taxa, and the specificity of microsatellite DNA is very high in protozoa. The results of this study will contribute to our understanding of microsatellite DNA in protozoa.

On the Asymptotic Behavior of Certain Second Order Differential Equations

Two criteria for asymptotic behavior of certain second order differential equations are obtained. The results extend and improve Feng's theorem.

A parametric study on the contact stress of half toroidal continuously variable transmission

The most general contact in mechanical transmission is the elliptical one. In particular, a toroidal continuously variable transmission (CVT) has an elliptical shape in the contact area under the elastohydrodynamic lubrication regime, where the shearing of the fluid subjects to high contact stress and transmits the power. Many parameters affect the contact service performance of the half toroidal CVT, which include the properties of the contacting material (Young抯 modulus), operating parameters (input torque and maximum traction coefficient) and geometrical parameters (aspect cavity ratio, curvature ratio and half cone angle of the power roller). In this paper, the contacts between the input disk, the power roller and the output disk are formulated using the classical Hertzian contact theory. Based on the formulated equations, different system parameters, which affect the maximum Hertzian stresses, are compared. The comparative results will provide some observations of the relations between the maximum Hertzian stresses and transmission ratios in the form of graphs. These graphs give useful information for designer to know the maximum Hertzian stress during operation in such systems.

Knowledge Discovery for Event Series Decision Based on Rough Set

To make decisions about event series is part of our life, and to discover knowledge from these decisions is of great significance in the field of controlling and decision-making. The paper takes event series as the exterior form of movements with the dynamic attributes, and gets the Markov transition probabilities matrix to express those attributes with statistics. First, according to the matrix, the decision table is constructed. Then, by reducing attributes based on rough set theory, the decision table is reduced, and the decision rules are acquired as well. Finally we make the decision through defining rule distance and taking the minimum rule distance as decision principle. Followed is an example, which proves that the algorithm is feasible and effective to the event series decision.

Construction management through bot: Taiwan high speed rall case

One of the key elements in real estate management is streamlining the construction process. Thus, the facilities can be built on a faster, cheaper, and higher quality base. Consequently, it will enhance the owner’s competitiveness. Due to the high cost and lengthy duration of mega-construction projects in recent years, Build-Operate-Transfer (BOT) contracts are getting popular in delivering constructed projects in the public sector. With BOT, the public owners are able to focus on the effectiveness of fair resource allocation as well as bring the efficiency of private enterprise into governmental operations. This paper uses Taiwan High Speed Rail project to exemplify the BOT method in executing the constructed projects in the chain of real estate management processes. The paper explains the reasons for building HSR and adopting BOT approach. The detail of the HSR project and the feasibility analysis of the project will be presented in this paper. The feasibility analysis comprises the comparisons of different transportation means, the financial analysis, and other benefits from HSR. Finally, conclusions will be drawn.