Role Of Barrier Layer Research Articles

Role of barrier layer in the developing phase of “Category 6” super typhoon Haiyan

With the remarkable intensity of 170 knots, Typhoon Haiyan started as a tropical depression on November 3 and developed to the peak as super tropical cyclone (TC) on November 7 in 2013. This intensity makes Haiyan one of the strongest TCs record ever observed and 35 knots higher than the maximum of the existing highest category. Haiyan originated from the eastern part of the Northwest Pacific Warm Pool and moved westward over warm water with a thick barrier layer (BL). The BL reduced the vertical mixing and entrainment caused by Haiyan and prevented the cold thermocline water into the mixed layer (ML). As a result, sea temperature cooling associated with wind stirring was suppressed. Relative high sea surface temperature (SST) kept fueling Haiyan via latent heat flux release, which favored the rapid development of a “Category 6” super typhoon

Role of barrier layer in the developing phase of “Category 6” super typhoon Haiyan

With the remarkable intensity of 170 knots, Typhoon Haiyan starts as a tropical depression on November 3 and develops to the peak as super tropical cyclone (TC) on November 7 in 2013. This intensity makes Haiyan one of the strongest TCs record ever observed and 35 knots higher than the maximum of the existing highest category. Haiyan originated from the eastern part of the Northwest Pacific Warm Pool and moved westward over warm water with a thick barrier layer (BL). The BL reduced the vertical mixing and entrainment caused by Haiyan and prevented the cold thermocline water into the mixed layer (ML). As a result, sea temperature cooling associated with wind stirring was suppressed. Relative high sea surface temperature (SST) kept fueling Haiyan via latent heat flux release, which favored the rapid development of a “Category 6” super typhoon.

Response of upper ocean and impact of barrier layer on Sidr cyclone induced sea surface cooling

In the present study an attempt has been made to investigate the impact of salinity stratification on the SST during the tropical cyclone (TC) passage. In this context, a severe post monsoon cyclone, Sidr, (Category 4) that developed over the south-eastern Bay of Bengal (BoB) during 11–16 November, 2007 was chosen as a case study. Pre-existence of a thick barrier layer (BL), temperature inversions and a higher effective oceanic layer for cyclogenesis (EOLC) were noticed along the path of the Sidr cyclone. The analysis of available Argo floats along the Sidr cyclone track also revealed less cooling during as well as after its passage as was reported from satellite derived SST. The role of BL on Sidr induced sea surface cooling was investigated using a diagnostic mixed layer model. Model results also depict the reduced sea surface cooling during the passage of Sidr. This is attributed to the presence of BL which results in the inhibition of the entrainment of cool thermocline water into the shallow mixed layer. Climatological as well as in situ observations of tropical cyclone heat potential (TCHP) and EOLC shows that the Sidr cyclone propagated towards the regions of higher EOLC.

The role of barrier layer in southeastern Arabian Sea during the development of positive Indian Ocean Dipole events

Using data from Argo and simple ocean data assimilation (SODA), the role of the barrier layer (BL) in the southeastern Arabian Sea (SEAS: 60°E–75°E, 0°–10°N) is investigated during the development of positive Indian Ocean Dipole (IOD) events from 1960 to 2008. It is found that warmer sea surface temperature (SST) in the northern Indian Ocean appears in June in the SEAS. This warm SST accompanying anomalous southeastern wind persists for six months and a thicker BL and a corresponding thinner mixed layer in the SEAS contribute to the SST warming during the IOD formation period. The excessive precipitation during this period helps to form a thicker BL and a thinner mixed layer, resulting in a higher SST in the SEAS. Warm SST in the SEAS and cold SST to the southeast of the SEAS intensify the southeasterly anomaly in the tropical Indian Ocean, which transports more moisture to the SEAS, and then induces more precipitation there. The ocean-atmosphere interaction process among wind, precipitation, BL and SST is very important for the anomalous warming in the SEAS during the development of positive IOD events.

ANALYSES OF SURFACE OXIDE FILMS ON ELECTROPOLISHED ALLOY 690TT AFTER IMMERSION FOR DIFFERENT TIMES

The corrosion of Ni base alloys in high temperature and high pressure water is affected by samples surface statuses.The morphologies and structures of surface oxide films grown on electropolished(EP) alloy 690TT after immersion in the simulated hydrogenated primary water of pressured water reactors(PWRs) for different times were analyzed by AFM,SEM,TEM,EDS and XPS.After immersion for 15 and 35 h,the EP alloy 690TT samples were covered with columnar oxides. With the increase of the immersion time,the sample surfaces were covered with scattered big oxide particles and loose needle-like oxides.Regardless of the immersion time,the formed oxide films are composed of spinel oxides and metallic Ni.After immersion for 720,1440 and 2160 h,the oxide films are composed of three layers:the outmost layer is the separated big oxide particles which are rich in Fe and Ni:the intermediate layer is the loose needle-like oxides rich in Ni;the inner layer is the continuous and compact Cr oxides.The peak decomposition of the XPS revealed that the Cr oxides in the inner layer are probably Cr_2O_3.Only the inner layer in the oxide film could restrain the outward diffusion of metal atoms and also the inward diffusion of the oxygen atoms and then played the role of barrier layer well. Electropolishing treatment disadvantaged the fast growth of protective oxide film on alloy 690TT in the studied solution.The average corrosion rate of the inner layer does not decrease gradually with increasing the immersion time.After immersion for 2160 h,the oxide film still could not protect the matrix from further corrosion.

Role of barrier layers in electroluminescence from SiN-based multilayer light-emitting devices

We report the effects of barrier layer on the electroluminescence properties of the SiN-based multilayer light-emitting devices (LEDs). It is found that the emission efficiency is significantly enhanced by more than one order of magnitude compared to that of LED without barrier layer. Meanwhile, the emission wavelength can also be tuned from 620to510nm by controlling the Si∕N ratio of the barrier layer. The improved performance of LEDs can be attributed to the variation in the band offset between the Si-rich SiN well layer and the N-rich SiN barrier layer.

Structure and crystallographic orientation of aluminum films on n-and p-silicon in the Al-Ti-Si and Al-Ti-SiOx-Si systems

The structure and crystallographic orientation of aluminum films in the Al-Ti-Si and Al-Ti-SiOx-Si systems is studied with the use of electron microscopic, electron diffraction, and x-ray methods and thermodynamic analysis. The role of barrier layers formed by Ti and by the “Ti-SiOx low-temperature oxide” composition in the formation and orientation of aluminum grains is determined.

Barrier layers for Cu ULSI metallization

Barrier layers are integral parts of many metal interconnect systems. In this paper we review the current status of barrier layers for copper metallization for ultra-large-scale-integration (ULSI) technology for integrated circuits (ICs) manufacturing. The role of barrier layers is reviewed and the criteria that determine the process window, i.e. the optimum barrier thickness and the deposition processes, for their manufacturing are discussed. Various deposition methods are presented: physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition (ECD), electroless deposition (ELD), and atomic layer CVD (ALCVD) for barrier layers implementation. The barrier integration methods and the interaction between the barrier and the copper metallization are presented and discussed. Finally, the common inspection and metrology for barrier layer are critically reviewed.