大跨度悬索桥桥塔施工监控指标研究

在悬索桥上部结构施工阶段,施工控制的主要计算参数包括桥塔预高量和桥塔允许偏位。以郭家沱长江大桥桥塔为例,利用Midas Civil建立桥塔的空间有限元模型,计算分析上部结构施工阶段桥塔的预高量、抗推刚度、抗扭刚度和允许偏位等。不同施工状态下索塔的抗推刚度和抗扭刚度是不一样的,考虑裸塔、空缆、成桥3个施工工况,通过对桥塔施加3个工况对应的荷载力,分析桥塔在不同工况下的抗推刚度和抗扭刚度;通过计算得出桥塔在不考虑温度修正的情况下预抬高量,以及猫道架设时的抗推刚度、抗扭刚度、允许水平偏位和允许扭转位移等参数,制定相关监控措施,为大桥的建设提供技术保障。

Expressway traffic flow prediction using chaos cloud particle swarm algorithm and PPPR model

Aiming at the real-time fluctuation and nonlinear characteristics of the expressway short-term traffic flow forecasting the parameter projection pursuit regression PPPR model is applied to forecast the expressway traffic flow where the orthogonal Hermite polynomial is used to fit the ridge functions and the least square method is employed to determine the polynomial weight coefficient c.In order to efficiently optimize the projection direction a and the number M of ridge functions of the PPPR model the chaos cloud particle swarm optimization CCPSO algorithm is applied to optimize the parameters. The CCPSO-PPPR hybrid optimization model for expressway short-term traffic flow forecasting is established in which the CCPSO algorithm is used to optimize the optimal projection direction a in the inner layer while the number M of ridge functions is optimized in the outer layer.Traffic volume weather factors and travel date of the previous several time intervals of the road section are taken as the input influencing factors. Example forecasting and model comparison results indicate that the proposed model can obtain a better forecasting effect and its absolute error is controlled within [-6,6] which can meet the application requirements of expressway traffic flow forecasting.

Regression model for daily passenger volume of high-speed railway line under capacity constraint

A non-linear regression model is proposed to forecast the aggregated passenger volume of Beijing-Shanghai high-speed railway(HSR) line in China. Train services and temporal features of passenger volume are studied to have a prior knowledge about this high-speed railway line. Then, based on a theoretical curve that depicts the relationship among passenger demand, transportation capacity and passenger volume, a non-linear regression model is established with consideration of the effect of capacity constraint. Through experiments, it is found that the proposed model can perform better in both forecasting accuracy and stability compared with linear regression models and back-propagation neural networks. In addition to the forecasting ability, with a definite formation, the proposed model can be further used to forecast the effects of train planning policies.

Glacier Changes during the Past 40 Years in the West Kunlun Shan

Recent studies on glaciers in the West Kunlun Shan, northwest Tibetan Plateau, have shown that they may be stable or retreating slightly. Here, we assess changes in the mass of the glaciers in the West Kunlun Shan(WKS) in an attempt to understand the processes that control their behavior. Glaciers over the recent 40 years(1970-2010) have shrunk 3.4±3.1%in area, based on a comparison between two Chinese glacier inventories. Variations of surface elevations, derived from ICESat-GLAS(Ice, Cloud, and Land Elevation Satellite-Geoscience Laser Altimeter System) elevation products(GLA14 data) using the robust linear-fit method, indicate that the glaciers have been gaining mass at a rate of 0.23±0.24 m w.e./a since 2003. The annual mass budget for the whole WKS range from 2003 to 2009 is estimated to be 0.71±0.62 Gt/a. This gain trend is confirmed by MOD10A1 albedo for the WKS region which shows a descent of the mean snowline altitude from 2003 to 2009.

Effect of copper on the growth of shrimps Litopenaeus vannamei : water parameters and copper budget in a recirculating system

Shrimps( Litopenaeus vannamei) were intensively cultured in a recirculating aquaculture system for 98 days to investigate effects of 0.3 mg/L Cu on its performance, Cu budget, and Cu distribution. Shrimps in Cu-treated systems had greater mean final weight(11.10 vs 10.50 g), body length(107.23 vs 106.42 mm), survival rate(67.80% vs 66.40%), and yield(6.42 vs 5.99 kg/m 3), and lower feed conversion ratio(1.20 vs 1.29) than those in control systems but the differences were not significant. Vibrio numbers remained stable(10 4 –10 6 colony forming units/mL) in the rearing tanks of both control and treated systems. Total ammonium-N, nitrite-N, nitrate-N, pH, chemical oxygen demand, 5-day carbonaceous biochemical oxygen demand, and total suspended solids were similar in controls and treatments. Dissolved Cu concentration in the treated systems decreased from 0.284 to 0.089 mg/L while in the control systems it increased from 0.006 2 to 0.018 mg/L. The main sources of Cu in the treated systems were the artificially added component(75.7% of total input), shrimp feed(21.0%), water(2.06%), and shrimp biomass(1.22%). The major outputs of Cu occurred via the mechanical filter(41.7%), water renewal(15.6%), and draining of the sediment trap(15.1%). The foam fractionator removed only 0.69% of total Cu input. Harvested shrimp biomass accounted for 11.68% of Cu input. The Cu concentration of shrimps in the Cu-treated systems(30.70 mg/kg wet weight) was significantly higher than that in control systems(22.02 mg/kg). Both were below the maximum permissible concentration(50 mg/kg) for Cu in seafood for human consumption in China. Therefore, recirculating systems can be used for commercial on-growing of Litopenaeus vannamei without loss of shrimp quality, even in water polluted by 0.30 mg/L Cu. The mechanical filter is the main route for Cu removal.

Kernelized fourth quantification theory for mineral target prediction

This paper presents a nonlinear multidimensional scaling model, called kernelized fourth quantifica- tion theory, which is an integration of kernel techniques and the fourth quantification theory. The model can deal with the problem of mineral prediction without defining a training area. In mineral target prediction, the pre-defined statistical cells, such as grid cells, can be implicitly transformed using kernel techniques from input space to a high-dimensional feature space, where the nonlinearly separable clusters in the input space are ex- pected to be linearly separable. Then, the transformed cells in the feature space are mapped by the fourth quan- tifieation theory onto a low-dimensional scaling space, where the sealed cells can be visually clustered according to their spatial locations. At the same time, those cells, which are far away from the cluster center of the majority of the sealed cells, are recognized as anomaly cells. Finally, whether the anomaly cells can serve as mineral potential target cells can be tested by spatially superimposing the known mineral occurrences onto the anomaly ceils. A case study shows that nearly all the known mineral occurrences spatially coincide with the anomaly cells with nearly the smallest scaled coordinates in one-dimensional sealing space. In the case study, the mineral target cells delineated by the new model are similar to those predicted by the well-known WofE model.

D2 Lymphadenectomy in Gastric Cancer Surgery

Gastric cancer is one of the most common causesof cancer death worldwide. Surgery is the most widely utilizedtreatment for resectable gastric cancer. Evidence indicates thatlymph node involvement and depth of invasion of the primarytumor are the most important prognostic factors for gastriccancer patients. Therefore, lymph node clearance is deemed akey procedure in gastric cancer surgery for the prognostic valueto patients. Although the appropriate lymphadenectomy duringgastrectomy for cancer still remains controversial, extendedlymph node dissection (D2 lymphadenectomy) should berecommended in high volume hospitals.

The Knee Wear Prediction of UHMWPE Tibial Insert Using VIPRO Platform

The failure mechanism was postulated as a combination of the high level of loading during normal activities and a non-conforming contact mechanism between the femoral condyles and the tibial insert. The question that arises is： could be this phenomenon evaluated quantitatively a priori, e.g., could be the failure due to delamination wear predicted？ In order to do some finite element simulations were performed to dynamically determinate the contact area and contact pressure for three different activities. The results obtained using VIPRO platform lead to the conclusion that many clinically reported failures of the tibial tray are caused by the adhesive and fatigue wear.

High Throughput Satellite System Capacity Analysis and Application Forecast

With the development of large numbers broadband Internet access,global satellite communications is moving towards High Throughput Satellites(HTS).Now,USA,Canada,Europe,Thailand,Japan,United Arab Emirates,Australia have already developed HTS systems.However,there is little research to analyze the factors influencing high throughput.Thus,from the design perspective,the throughput of HTS and influencing factors are calculated and compared at a system level.Finally,the application of HTS is analyzed and forecasted.

Analysis of external noise spectrum of high-speed railway

A schematic to make the spectra of the exterior noise of high speed railway was put forward. The exterior noise spectrum was defined based on the characteristics of the high-speed train exterior noise. Its characteristics considered here include identifying the exterior main sources and their locations, their frequency components including the Doppler effect due to the noise sources moving at high speed, the sound field intensity around the train in high-speed operation, the sound radiation path out of the train, and the pressure level and frequency components of the noise at the measuring points specified by the International Organization for Standardization(ISO). The characteristics of the high-speed train exterior noise of the high speed railways in operation were introduced. The advanced measuring systems and their principles for clearly indentifying the exterior noise sources were discussed in detail. Based on the concerned noise results measured at sites, a prediction model was developed to calculate the sound level and the characteristics of the exterior noise at any point where it is difficult to measure and to help to make the exterior noise spectrums. This model was also verified with the test results. The verification shows that there is a good agreement between the theoretical and experimental results.

Effects of Preheat on the Thermodynamics of the ICF Hot Spot

We determine the dependence of key inertial confinement fusion （ICF） hot spot properties on the deuterium-tritium （DT） fuel adiabat accomplished by addition of heat to the cold shell. Our main result is to observe that variation of this parameter reduces the simulation to experiment discrepancy in several experimentally inferred quantities. Simulations are continued from capsule only l D simulations using the Lawrence Livermore National Laboratory ICF code, HYDRA. The continuations employ the high energy density physics （HEDP） University of Chicago code, FLASH, and a hydro only code, FronTier, modified with a radiation equation of state （EOS） model. Hot spot densities, burn-weighted ion temperatures and pressures show a decreasing trend, while the hot spot radius shows an increasing trend in response to added heat to the cold shell. Instantaneous quantities are assessed at the time of maximum neutron production within each simulation.

Optimal channels of the Garvey-Kelson mass relations in extrapolation

Garvey-Kelson mass relations connect nuclear masses of neighboring nuclei within high accuracy, and provide us with convenient tools in predicting unknown masses by extrapolations from existent experimental data. In this paper we investigate optimal"channels" of the Garvey-Kelson relations in extrapolation to the unknown regions, and tabulate our predicted masses by using these optimized channels of the Garvey-Kelson relations.

通信枢纽楼能耗运行分析研究

如何在业务量不断增加,电源容量无法扩容的情况下,更好地解决供电能力紧张、机房装机位不足、机房散热等问题,是本论文的研究意义所在。本文通过对S省通信枢纽楼能耗运行分析,给出以上难点的合理化建议和建设指导原则。