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用碳纳米管来计算

科技纵览 2016年第7期 26-31页

作者： Max Shulaker 黄汉森 subhasish mitra

半个多世纪以来，硅半导体行业一直在大步前进，压路机般碾过沟坎，公然藐视“燃料将耗尽”“将被竞争者取代”的一再警告。可以理解，技术人员们不太愿意去预测硅时代的结束。但我们必须作出推测。在过去几十年中，随着硅晶体管物理尺... 详细信息

半个多世纪以来，硅半导体行业一直在大步前进，压路机般碾过沟坎，公然藐视“燃料将耗尽”“将被竞争者取代”的一再警告。可以理解，技术人员们不太愿意去预测硅时代的结束。但我们必须作出推测。在过去几十年中，随着硅晶体管物理尺寸的不断缩小，计算机芯片的效率和速度逐步改善，现在开关的微型化对性能改进的作用已不明显。压路机还在前进，

关键词：计算机芯片碳纳米管硅晶体管半导体行业技术人员性能改进压路机微型化

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防木马芯片

科技纵览 2015年第2期 44-49页

作者： subhasish mitra H. S. Philip Wong Simon Wong

很久以前，有这样一个故事，希腊士兵花了10年工夫想攻克特洛伊城，可最终他们离开了，留下了一个巨大的木马。特洛伊人以为那是一件漂亮的礼物，将其拉进城内。当晚，一群希腊士兵从马肚子里溜出来，为其战友打开了城门，进而将这座睡... 详细信息

很久以前，有这样一个故事，希腊士兵花了10年工夫想攻克特洛伊城，可最终他们离开了，留下了一个巨大的木马。特洛伊人以为那是一件漂亮的礼物，将其拉进城内。当晚，一群希腊士兵从马肚子里溜出来，为其战友打开了城门，进而将这座睡梦中的城市洗劫一空。时间过去了差不多3000年，如今，特洛伊木马是指看似无害但实际上却含有恶意代码的软件。安全公司不断开发新的测试方法来检测这些代码的威胁性。然而．木马还有另外一种变体——“硬件木马”，它刚刚开始受到关注，且被证明更难破解。

关键词：特洛伊木马芯片恶意代码测试方法士兵希腊软件硬件

基于软熔行为的烧结矿与纽曼混合块矿的高炉数值模拟

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基于软熔行为的烧结矿与纽曼混合块矿的高炉数值模拟

Fluid Inclusion Characteristics of Tungsten Mineralization in the Agargaon Area of Sakoli Fold Belt, Central India

2019年全国高炉炼铁学术年会

作者：刘新亮 Tom Honeyands Paul Zulli Damien O'Dea Geoffrey Evans subhasish mitra 邱光君必和必拓铁矿市场澳大利亚纽卡斯尔大学ARC先进铁矿石技术研究中心澳大利亚卧龙岗大学ARC炼钢研究中心

本文试验研究了烧结矿、纽曼混合块矿（NBLL）及二者混合炉料的软熔行为,并采用数值模拟考察了其在高炉内的性能;研究结果表明在软熔过程中烧结矿与NBLL间存在着明显的物理和化学交互作用,此反应明显地改善了烧结矿-NBLL混合炉料的软熔... 详细信息

本文试验研究了烧结矿、纽曼混合块矿（NBLL）及二者混合炉料的软熔行为,并采用数值模拟考察了其在高炉内的性能;研究结果表明在软熔过程中烧结矿与NBLL间存在着明显的物理和化学交互作用,此反应明显地改善了烧结矿-NBLL混合炉料的软熔行为。通过使用同步辐射X射线和中子CT扫描软熔试验试样,发现混合炉料的孔隙度与单一烧结矿相近,并明显高于单一块矿,即烧结矿与NBLL间存在着物理交互作用;扫描电镜分析证实1200℃左右烧结矿中的钙开始向NBLL扩散,二者发生了明显的化学交互作用。在软熔试验基础上,高炉数值模拟结果亦证实烧结矿-NBLL混合炉料行为与单一烧结矿更接近;与具有相同炉料碱度的烧结矿相比,烧结矿-NBLL混合炉料在高炉内软熔带透气性更好、全炉压差更低、煤气利用率更高。

关键词：块矿烧结矿交互作用软熔带高炉

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Journal of Earth Science 2020年第3期31卷 559-570页

作者： Girish Kumar Mayachar subhasish Ghosh National Centre for Excellence in Geoscience Research Remote Sensing and Aerial SurveyGeological Survey of IndiaBangalore 560078India

The Lower to Middle Proterozoic Sakoli fold belt in Central India forms a triangular belt with significant mineralization of strategic *** Sakoli fold belt comprises metasediments,felsic and mafic volcanics with metabasalts bounded by the gneissic-migmatitic *** last pulses of granitic activity in the form of quartz lenses intrude the metasediments and are associated with tungsten *** metasediments are intruded by the quartz veins and tourmaline breccias trending 60°N to 65°E and 60°S to 65°W and are parallel to the regional structural *** tungsten mineralization in this area is restricted to tourmaline-quartz mica greisens and quartz *** NE-SW trending foliated contact zones of chlorite mica schist and porphyritic granite/gneisses have served as easy channels for the mineralizing vapours and solutions to percolate,which formed ore bearing greisens and quartz *** mineralization is erratic and manifested by sparse and sporadic disseminations of wolframite and scheelite associated with minor amount of molybdenite and *** fluid inclusion microthermometry on mineralized quartz veins and quartz-tourmaline veins reveals the existence of a metamorphogenic aqueous-gaseous(H2O-CO2+NaCl)fluid that underwent phase separation and gave rise to gaseous(CO2)*** salinity of tungsten mineralizations varies from low to high(1.32 wt.%to 40.44 wt.%NaCl eq.).The estimated P-T range of tungsten mineralization varies from 1.2 to 2.2 kbar at 280 to 390℃.Raman spectroscopy reveals that the fluid inclusions mainly contain H2O and CO2 with rarely H2S and *** isotopic data reveal that the sulfur isotope fractions from the depositsδ^34S ranging from+3.1‰to+3.35‰,suggesting the deep crustal source for the sulfur,which can be further interpreted as a single(magmatic)supply of sulfur during magmatic-hydrothermal *** studies reveal the presence of chlorides such as FeCl2/MgCl2 and CaCl2,indicating t

关键词： Sakoli fold belt fluid inclusions tungsten

Influence of bank vegetation and gravel bed on velocity and Reynolds stress distributions

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International Journal of Sediment Research 2009年第2期24卷 236-246页

作者： Hossein AFZALIMEHR subhasish DEY Department of Water Engineering Isfahan University of Technology Department of Civil Engineering Indian Institute of Technology

This paper presents the results of a laboratory flume experimental study on the interaction of bank vegetation and gravel bed on the flow velocity(primarily on the location of the maximum velocity,Umax) and the Reynolds stress distributions. The results reveal that the dip of the maximum velocity below the water surface is up to 35% of flow depth and the difference between Umax and the velocity at the water surface is considerable in the presence of vegetation on the walls. The zone of the log-law varies from y/h=2 up to 15 percent of flow depth and it does not depend on distance from the wall. Deviation of the velocity profile in the outer layer over a gravel bed with vegetation cover on the walls is much larger than the case of flow over a gravel bed without vegetation cover on the walls. The presence of vegetation on the walls changes uniform flow to non-uniform flow. This fact can be explained by considering the nonlinear Reynolds stress distribution and location of maximum velocity in each profile at different distances across the flume. The Reynolds stress distributions at the distance 0.02 m from the wall have negative values and away from the wall,they change the sign taking positive values with specific convex form with apex in higher location. Average of von Karman constant κ for this study is equal to 0.16. Based on κ=0.16,the methods of Clauser and the Reynolds stress are compatible for determination of shear velocity.

关键词： Bank vegetation Uniform flow Reynolds stress Gravel bed Von Karman constant

Circulation characteristics of horseshoe vortex in scour region around circular piers

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Water Science and Engineering 2013年第1期6卷 59-77页

作者： subhasish DAS Rajib DAS Asis MAZUMDAR School of Water Resources Engineering Jadavpur University

This paper presents an experimental investigation of the circulation of the horseshoe vortex system within the equilibrium scour hole at a circular pier, with the data measured by an acoustic Doppler velocimeter （ADV）. Velocity vector plots and vorticity contours of the flow field on the upstream plane of symmetry （y = 0 cm） and on the planes ：e3 cm away from the plane of symmetry Cv = ~3 cm） are presented. The vorticity and circulation of the horseshoe vortices were determined using the forward difference technique and Stokes theorem, respectively. The results show that the magnitudes of circulations are similar on the planes y = 3 cm and y = -3 cm, which are less than those on the plane y = 0 cm. The circulation decreases with the increase of flow shallowness, and increases with the densimetric Froude number. It also increases with the pier Reynolds number at a constant densimetric Froude number, or at a constant flow shallowness. The relative vortex strength （dimensionless circulation） decreases with the increase of the pier Reynolds number. Some empirical equations are proposed based on the results. The predicted circulation values with these equations match the measured data, which indicates that these equations can be used to estimate the circulation in future studies.

关键词： experimental investigation," open channel turbulent flow," scour," horseshoe vortex,"circulation," circular pier forward difference technique," Stokes theorem

Interfacial instability of sand patterns induced by turbulent shear flow

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International Journal of Sediment Research 2021年第4期36卷 449-456页

作者： Sk Zeeshan Ali subhasish Dey Department of Civil Engineering Indian Institute of Technology Hyderabad Department of Civil Engineering Indian Institute of Technology Kharagpur Department of Hydraulic Engineering State Key Laboratory of Hydro-Science and Engineering Tsinghua University

When a turbulent shear flow above a plane sand surface entrains sand grains, it generates a variety of sand patterns. Fluvial sand forms two major interfacial patterns: meso-scale dunes and antidunes, and large-scale bars. Measurements have evidenced that under erosive conditions, meso-scale patterns either change to or coexist with large-scale patterns. However, it remains elusive what exactly drives the switching of interfacial patterns and how the switching occurs. Here, we showdcombing a flow model with a grain transport model, allowing for both the surface and suspended sand fluxes dthat the switching of patterns emerges from the shear-driven complex feedback between grain transport and topographic perturbations. The switching predominantly depends on the magnitudes of the Rouse number and the grain size to undisturbed flow depth ratio. The model offers quantitative predictions of the maximum amplification of sand patterns and unveils a new attraction erepulsion phenomenon.

关键词： Instability Sand patterns Turbulent flow Sediment transport

Intrusion Detection System Using Classification Algorithms with Feature Selection Mechanism over Real-Time Data Traffic

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China Communications 2024年第9期21卷 292-320页

作者： Gulab Sah Sweety Singh subhasish Banerjee Computer Science and Engineering National Institute of Technology Arunachal PradeshIndia

The key objective of intrusion detection systems(IDS)is to protect the particular host or network by investigating and predicting the network traffic as an attack or *** IDS uses many methods of machine learning(ML)to learn from pastexperience attack *** based and identify the new *** though these methods are effective,but they have to suffer from large computational costs due to considering all the traffic features,***,emerging technologies like the Internet of Things(Io T),big data,*** getting advanced day by day;as a result,network traffics are also increasing ***,the issue of computational cost needs to be addressed ***,in this research,firstly,the ML methods have been used with the feature selection technique(FST)to reduce the number of features by picking out only the important ones from NSL-KDD,CICIDS2017,and CIC-DDo S2019datasets later that helped to build IDSs with lower cost but with the higher performance which would be appropriate for vast scale *** experimental result demonstrated that the proposed model *** tree(DT)with Recursive feature elimination(RFE)performs better than other classifiers with RFE in terms of accuracy,specificity,precision,sensitivity,F1-score,and G-means on the investigated datasets.

关键词： CICIDS2017 dataset classifiers IDS ML NSL KDD dataset RFE

Suspended load in flows on erodible bed

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International Journal of Sediment Research 2009年第3期24卷 315-324页

作者： Sujit K. BOSE subhasish DEY Visiting Fellow Department of Civil Engineering Indian Institute of Technology Chair Prof. Department of Civil Engineering Indian Institute of Technology

Steady state suspended-load of sediment transported in flow over erodible beds usually is treated by the advection-diffusion approach, though in recent years, it is being treated as a two-phase flow phenomenon incorporating kinetics of sediment particles. Among the advection-diffusion approaches, Rouse’s equation is the well-known, although a number of researchers in later periods have attempted to improve it by modifying the mixing length concept taking into account other aspects. In this paper, the advection-diffusion approach and associated logarithmic law of flow velocity are revisited. It is concluded from the logarithmic law that the Reynolds shear stress is a linear function of height above the bed, which reduces to bed shear stress in the case of a long horizontal channel. As a consequence, it is shown that the volumetric concentration of sediment is best approximated by the sum of two power laws of height above the bed. An equation is derived for the suspended-load transport rate in terms of elementary functions.

关键词： Sediment transport Fluvial hydraulics Suspended load Open channel flow