Parameter variation aware hybrid TFET-CMOS based power gating technique with a temperature variation tolerant sleep mode

In this work, we discuss the origin and temperature dependence of various mechanisms behind the flow of leakage current in two topologies of TFET – basic TFET and pocket doped TFET. It is shown that the leakage current of pocket doped TFET shows relatively less variations with change in temperature when compared with MOSFET and basic TFET, and hence they can be deployed in low voltage temperature variation prone applications. But, this advantage of pocket-doped TFET is overshadowed by the huge sensitivity of its ON-state current towards variations in doping concentration at the tunnel junction. Hence, the fabrication of the TFET based circuits requires a negotiation with the yield and cost of the fabrication process. In order to mitigate this issue, we propose a hybrid TFET-CMOS based power gating technique. The hybrid technique utilizes a minimum number of TFETs to reduce the sleep mode leakage current, while enabling a temperature variation tolerant sleep mode at a supply voltage of 0.6 V.     

活塞效应效率对地铁轨道区排热的影响

针对地铁轨行区不同的通风模式,利用SES软件对某地铁进行模拟计算,分别分析了正常工况下轨行区有、无轨道排热系统两种情况下的隧道空气温度分布情况,得到无TES比有TES时隧道空气最高温度高2.9℃的结论。通过分析不同模式下的活塞效应效率值来解释导致2.9℃温差的原因。     

Overall photocatalytic water splitting on Na2ZrxTi6−xO13 (x = 0, 1) nanobelts modified with metal oxide nanoparticles as cocatalysts

In this work, we present the preparation of Na₂Zr_xTi_6?xO₁₃ (x = 0, 1) nanobelts through a rapid solvocombustion method. The phases exhibited stable photocatalytic activity for overall water splitting under UV light. Effect of the annealing temperature on the physicochemical properties and the catalytic performance of the materials were studied. Na₂ZrTi₅O₁₃ exhibited a higher rate of H₂ evolution compared to Na₂Ti₆O₁₃, and it was attributed to the incorporation of Zr⁴⁺ in the structure, which generates a distortion in the octahedral sites of the structure. This distortion promoted an enhanced charge transport and a reduction in the recombination of the free carriers and a higher photocatalytic activity. The nanobelts were superficially modified through the deposition of metal oxide nanoparticles as cocatalyst, MO (M = Ni, Cu). The incorporation of metal oxide nanoparticles improved the charge separation process and the overall efficiency. An integral study of the structural, morphological, textural, optical and photoelectrochemical properties of the materials is presented and a charge transference mechanism on the semiconductor interface is proposed. The highest catalytic activity was obtained by Na₂ZrTi₅O₁₃ modified with CuO (2909 μmol g?¹ h^?1), and corresponds to an increase of 13.6 times the activity of the bare photocatalyst. This was attributed to an improved charge separation at the interface of n-type Na₂ZrTi₅O₁₃ and p-type CuO semiconductors. For the best of our knowledge, the activity exhibited for overall water splitting of Na₂Zr_xTi_6?xO₁₃ (x = 0, 1) nanobelts prepared by solvocombustion method and modified with the addition of MO nanoparticles in this work is higher compared to the reported in previous works.     

Effects of buoyancy induced roof ventilation systems for smoke removal in tunnel fires

The present article highlights the performance of natural roof ventilation systems and its effects on tunnel fire flow characteristics. Numerical analysis is performed using Large Eddy Simulations (LES) to predict fire growth rate and smoke movement in tunnel with single and multiple roof openings. The smoke venting performance of ceiling vents are investigated by varying the vent size and fire source locations. The critical parameters such as mass flow rate through ceiling openings, smoke traveling time and fire growth patterns are presented. The ceiling openings are effective in transferring hot gases and reduces the longitudinal smoke velocity. The heat source and ceiling vent locations significantly affects the vent performance and smoke behavior in tunnel. The present results are in good agreement with the experimental results available in literature.     

引汉济渭工程秦岭隧洞围岩稳定性有限元分析

对引汉济渭工程秦岭引水隧洞开挖的初期支护施工过程围岩结构的塑性变形分布规律进行分析研究,结合计算结果,为初期支护过程围岩的稳定性提供分析依据,以便对现场施工提供合理化建议。采用非线性弹塑性有限元法,依据地下结构设计理论及岩石的Drucker-Prager屈服准则,考虑围岩和初期支护衬砌结构的整体性,对秦岭引水隧洞的Ⅲ、Ⅳ类围岩开挖和初期支护结构的施工过程进行了模拟,计算了开挖施工过程三种不同工况下围岩顶拱及侧向的塑性变形。结果表明:秦岭隧洞初期支护施工过程的三种工况下围岩结构的塑性变形主要集中在顶拱120°范围内及两侧边墙,隧洞围岩结构整体处于安全状态。     

Modelling and optimization of the firing zone of a tunnel kiln to predict the optimal feed locations and mass fluxes of the fuel and secondary air

Optimization of the firing zone was done to minimize the fuel cost as being the objective function by finding the optimal operating variables. These variables are the initial admixed coal (AC) in the brick body, the mass flux and locations of pulverized coal (PC) and the secondary air required for complete combustion. The constraints are the carbon coming from the AC which increases the porosity of the bricks, and should be consumed completely. Two other constraints to avoid thermal shock are the temperature difference between bricks and air, and the maximum heating rate of the bricks. The results were compared to the plant data.     

Analysis of tunnel diode antenna using iterative method

An efficient iterative method, based on the wave concept has been used to analyze the printed tunnel diode integrated antenna. A high computational speed has been achieved by introducing a 2D fast Fourier transformation (2D-FFT) in wave-guide environment. The simulated results are compared with published data and a good agreement is observed.     

龙耀路越江隧道通风系统设计

根据龙耀路越江隧道分期实施投入运营的情况,介绍了隧道通风系统设计。接着介绍了通风设备配置情况。最后分析了隧道峒口内环境,经计算,CO浓度均满足设计标准。     

公路隧道给水系统中的超压问题及其措施

针对公路隧道给水系统的超压问题,指出三种减压措施的利与弊,并着重介绍减压阀在公路隧道中的选用要点、安装维护以及注意事项。     

龙耀路越江隧道中智能消防疏散指示系统的应用

越江隧道为人员密集型场所,针对火灾消防逃生的需求,系统地介绍智能消防疏散指示系统。以龙耀路越江隧道为例,从系统设置、布线、工作方式和效果等角度阐述了该系统在越江隧道中的实际应用。