大力发展长定尺钢轨 满足客运专线建设需要

长定尺钢轨可以大大提高钢轨的整体平顺性,钢轨长尺化生产可以大大提高其成材率。由于探伤后再锯切,可保证钢轨端头的内部质量,增加定尺钢轨的长度,减少焊接接头的数量,提高轨道运行的平顺性及安全可靠性。介绍长定尺钢轨的长度,指出发展长定尺钢轨需要解决的问题,例如长定尺钢轨生产技术改造、运输、焊接及在我国铁路的实施步骤。

Long-term variability of the sharp thermocline in the Yellow and East China Seas

Based on observed temperature data since the 1950s, long-term variability of the summer sharp thermocline in the Yellow Sea Cold Water Mass （YSCWM） and East China Sea Cold Eddy （ECSCE） areas is examined. Relationships between the thermocline and atmospheric and oceanic forcing were investigated using multiyear wind, Kuroshio discharge and air temperature data. Results show that： 1） In the YSCWM area, thermocline strength shows about 4-year and 16-year period oscillations. There is high correlation between summer thermocline strength and local atmospheric temperature in summer and the previous winter; 2） In the ECSCE area, interannual oscillation of thermocline strength with about a 4-year period （stronger in El Nifio years） is strongly correlated with that of local wind stress. A transition from weak to strong thermocline during the mid 1970s is consistent with a 1976/1977 climate shift and Kuroshio volume transport; 3） Long-term changes of the thermocline in both regions are mainly determined by deep layer water, especially on the decadal timescale. However, surface water can modify the thermocline on an interannual timescale in the YSCWM area.

Quantum-Mechanical Study on Surrounding-Gate Metal-Oxide-Semiconductor Field-Effect Transistors

As the channel length of metal-oxide-semiconductor field-effect transistors （MOSFETs） scales into the nanometer regime, quantum mechanical effects are becoming more and more significant. In this work, a model for the surrounding-gate （SG） nMOSFET is developed. The SchrSdinger equation is solved analytically. Some of the solutions are verified via results obtained from simulations. It is found that the percentage of the electrons with lighter conductivity mass increases as the silicon body radius decreases, or as the gate voltage reduces, or as the temperature decreases. The eentroid of inversion-layer is driven away from the silicon-oxide interface towards the silicon body, therefore the carriers will suffer less scattering from the interface and the electrons effective mobility of the SG nMOSFETs will be enhanced.

Investigation of the Grain Growth Evolution in the AISI 304H Austenitic Stainless Steel

The austenitic stainless steels usually present an excellent combination of corrosion resistance and mechanical properties such as ductility in the annealed condition and high yield strength after cold deformation. Solution annealing in the AISI 304H is recommended before deformation process in order to improve ductility. However, long annealing during solution annealing can cause GG （grain growth） or AGG （abnormal grain growth） in the AISI 304H. In these cases, ductility is strongly decreased. Therefore, GG or AGG must be avoided during solution annealing. In this article, grain growth during solution annealing of the AISI 304H samples was determined. Samples of the AISI 304H were annealed at 1,100 ℃ for solution-annealing times varying from 15 min to 180 min. The results show that AGG took place for samples annealed at 1,100 ℃ for 30 min. In this condition, grain size reached 70 ± 10 μm. After annealing solution at 1,100 ℃ for 180 min, grain size reached 120 ~ 20 μm. In summary, the results shown that solution annealing at 1,100 ℃ even for relatively short annealing promotes the prompt increase of the grain size.

Dynamic Simulation of Carbon Sequestration by Pinus sylvestris var. mongolica

Based on the functional process of carbon sequestration of forest, we categorize carbon sequestration in two parts： carbon capture and carbon storage. Here,Pinus sylvestris var.mongolica was used to simulate the dynamic changing process of carbon sequestration of forest in a century using tree growth formula and the cost of carbon capture and sequestration. We found that the total carbon captured and stored by 100-year-old P. sylvestris var.mongolica are both 966 kg C tree^-1. On the assumption that the current year is the planting year, the present total carbon sequestration value （capital value） of 100-year-old P. sylvesrtis var.mongolica is 54.78 USD tree^-1 at the discount rate of 3%, with the present total carbon capture value of 18.92 USD tree^-1 and carbon storage value of 35.86 USD tree^-1. The dynamic process of the annual value of carbon capture is ilustrated by an upside-down U shape curve, while that of carbon storage service folows an S shape curve. The combination of the dynamic processes of carbon capture value and carbon storage value represent the changing process of carbon sequestration value, which appears to be an S shape curve.