A1/A1-Oxide Interface Diffusion During Electromigration

1995 ◽  
Vol 391 ◽  
Author(s):  
R.A. Augur ◽  
R.A.M. Wolters ◽  
W. Schmidt ◽  
S. Kordić
Keyword(s):  
Grain Boundaries ◽  
Current Density ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Oxide Interface ◽  
Interface Diffusion ◽  
The Past ◽  
Wide Range ◽  
Extended Range ◽  
Modification Of The Surface

AbstractThis paper presents new results concerning diffusion at the interface between Al and its oxide, due to electromigration in Al interconnects. The results show that the phenomenon is an important and general one. Significant large-scale modification of the surface of Alalloy conductors was observed after electromigration stress under a wide range of different conditions: 1) in a number of different alloys (Al-Si, Al-Cu, Al-Si-V & Al-Si-V-Pd), 2) with and without passivation, 3) over an extended temperature range, 4) over an extended range of current density, and 5) with a number of different underlayers (SiO2, W-Ti (no vacuum-break before Al deposition) and W-Ti (oxidized surface before Al deposition)). After electromigration stressing, the surface showed height variations: at certain locations the original thickness remained, while at adjacent locations the thickness was reduced; as much as 150nm in 2500 hrs, for Al-Si on oxidized W-Ti metallization. Damage by thinning has received little attention in the past. Based on the results presented, a model for the underlying mechanism is proposed. In this model Al atoms diffuse concurrently along the interface between the Al-metal and its oxide, and through the grain boundaries, even at low stress conditions and in non-bamboo lines.

Making Memories Unavailable

2007 ◽  
Vol 215 (1) ◽  
pp. 4-11 ◽  
Author(s):  
Karl-Heinz Bäuml
Keyword(s):  
Memory Representation ◽  
Prior Work ◽  
Experimental Paradigm ◽  
Memory Tests ◽  
Inhibitory Processes ◽  
The Past ◽  
Wide Range ◽  
Extended Range ◽  
Subsequent Recall ◽  
Retrieval Blocking

Abstract. Research from the past decades has shown that cuing and retrieval are not always beneficial for episodic memory and can also be detrimental. Prior work assumed that these detrimental effects are caused by retrieval blocking, in which cuing and retrieval strengthen material and the repeated involuntary sampling of the strengthened material hinders subsequent recall of nonstrengthened targets. Using a new experimental paradigm and an extended range of memory tests, recent research indicates that the detrimental effects of retrieval and cuing occur across a wide range of memory tests and are likely to be the result of inhibitory processes. These inhibitory processes impair the nonretrieved and noncue items' memory representation and make these items unavailable in memory. The recent results and the new theory are reviewed and discussed.

scholarly journals Improved gene co-expression network quality through expression dataset down-sampling and network aggregation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Franziska Liesecke ◽  
Johan-Owen De Craene ◽  
Sébastien Besseau ◽  
Vincent Courdavault ◽  
Marc Clastre ◽  
...  
Keyword(s):  
Large Scale ◽  
Expression Profiles ◽  
Expression Data ◽  
Rna Seq ◽  
Network Construction ◽  
The Past ◽  
Wide Range ◽  
Gene Associations ◽  
New Gene ◽  
Network Quality

Abstract Large-scale gene co-expression networks are an effective methodology to analyze sets of co-expressed genes and discover new gene functions or associations. Distances between genes are estimated according to their expression profiles and are visualized in networks that may be further partitioned to reveal communities of co-expressed genes. Creating expression profiles is now eased by the large amounts of publicly available expression data (microarrays and RNA-seq). Although many distance calculation methods have been intensively compared and reviewed in the past, it is unclear how to proceed when many samples reflecting a wide range of different conditions are available. Should as many samples as possible be integrated into network construction or be partitioned into smaller sets of more related samples? Previous studies have indicated a saturation in network performances to capture known associations once a certain number of samples is included in distance calculations. Here, we examined the influence of sample size on co-expression network construction using microarray and RNA-seq expression data from three plant species. We tested different down-sampling methods and compared network performances in recovering known gene associations to networks obtained from full datasets. We further examined how aggregating networks may help increase this performance by testing six aggregation methods.

A Study on the Establishment of Criteria for Reduction measures of Mega Drought in Korea

2020 ◽  
Author(s):  
Park MooJong ◽  
Song Youngseok ◽  
Lee Heesup ◽  
Park Juhyeok
Keyword(s):  
Disaster Response ◽  
Large Scale ◽  
Technology Development ◽  
Development Program ◽  
Severity Index ◽  
Moisture Index ◽  
The Past ◽  
Wide Range ◽  
The Republic ◽  
Drought Damage

<p>Recently, climate change due to global warming has been frequented by large-scale weather disasters that have not been experienced in the past. Among various weather disasters, drought is one of the representative weather disasters in Korea recently along with heavy rains. In the case of drought, it occurs in a wide range in the short term and long term, and it is difficult to identify specific occurrence times, places, and causes, and damage and influence are enormous.</p><p>In the past, the Republic of Korea has been prepared with non-structural measures such as securing irrigation water for drought restoration, developing emergency management, and developing a drought information system based on drought index. The reduction measures for drought degradation were mainly used by Palmer Draught Severity Index (PDSI), Standardized Precision Index (SPI), Crop Moisture Index (CMI), Crop Specific Drug Index (CMI), and Profication (DICS Index), and Survey.</p><p>In this study, we intend to establish standards for reducing drought damage by investigating and analyzing drought damage characteristics in Korea. In the past, drought damage in Korea occurred in agriculture, living and industry, and the ministry manages and stores the data on drought damage. The drought damage in South Korea from 1965 to 2018 occurred a total of 204 times, mostly in South Gyeongsang and South Jeolla provinces, rather than in special cities and metropolitan cities. The purpose of this study is to analyze the characteristics of drought damage in Korea and establish the measures to reduce mega drought.</p><p>Acknowledges : This research was supported by a grant(2019-MOIS31-010) from Fundamental Technology Development Program for Extreme Disaster Response funded by Korean Ministry of Interior and Safety(MOIS).</p>

scholarly journals Convalescent Plasma Therapy: a Possible Treatment of COVID-19 Pandemic

2020 ◽  
Vol 2 (2) ◽  
pp. 45-47
Author(s):  
Shubha Devi Sapkota ◽  
Monika Sharma ◽  
Gehendra Bhusal
Keyword(s):  
Infectious Disease ◽  
Clinical Trials ◽  
Severe Acute Respiratory Syndrome ◽  
Large Scale ◽  
Alternative Therapy ◽  
Lung Damage ◽  
Plasma Therapy ◽  
The Past ◽  
Wide Range ◽  
Severe Infections

COVID 19 is a newly recognized infectious disease that has rapidly spread with no verified treatment available. It is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-COV-2). In Convalescent plasma therapy, the yellowish liquid or the plasma from the recovered blood is used to treat the patient suffering from the same illness. For more than 100 years it has been used to treat severe infections with varying degrees of success. For this present infection, multiple clinical trials on plasma therapy are still under vigorous investigations. Despite the very low chance of risks like allergies, lung damage, and transmission of blood-related infection, the therapy has shown a positive result in the recovery of the patients. Many experts are observing its use as a “stopgap measure” until effective vaccines and antiviral drugs are available in a wide range. However, the main challenges faced are finding suitable donors, its expensiveness in the whole procedure, and inability to perform on a large scale. In this commentary, summarization of the convalescent plasma therapy is done as a hopeful alternative therapy of severe or critical COVID 19. It has also emphasized the promising results shown since the past while the use of this therapy in various infectious diseases.

scholarly journals A new golden age: testing general relativity with cosmology

2011 ◽  
Vol 369 (1957) ◽  
pp. 4941-4946
Author(s):  
Rachel Bean ◽  
Pedro G. Ferreira ◽  
Andy Taylor
Keyword(s):  
General Relativity ◽  
Large Scale ◽  
Large Scale Structure ◽  
Einstein Gravity ◽  
Field Equations ◽  
The Past ◽  
Cosmological Observations ◽  
Wide Range ◽  
Theories Of Gravity ◽  
The Universe

Gravity drives the evolution of the Universe and is at the heart of its complexity. Einstein's field equations can be used to work out the detailed dynamics of space and time and to calculate the emergence of large-scale structure in the distribution of galaxies and radiation. Over the past few years, it has become clear that cosmological observations can be used not only to constrain different world models within the context of Einstein gravity but also to constrain the theory of gravity itself. In this article, we look at different aspects of this new field in which cosmology is used to test theories of gravity with a wide range of observations.

Taking Measure of the UN's Legacy at Seventy-Five

2020 ◽  
Vol 34 (3) ◽  
pp. 285-295
Author(s):  
David M. Malone ◽  
Adam Day
Keyword(s):  
Cold War ◽  
Large Scale ◽  
New Technologies ◽  
The United States ◽  
First Century ◽  
Post Cold War ◽  
The Past ◽  
Wide Range ◽  
New Thinking ◽  
New Ideas

AbstractOver the past seventy-five years, the UN has evolved significantly, often in response to geopolitical dynamics and new waves of thinking. In some respects, the UN has registered remarkable achievements, stimulating a wide range of multilateral treaties, promoting significant growth of human rights, and at times playing a central role in containing and preventing large-scale armed conflict. As part of the special issue on “The United Nations at Seventy-Five: Looking Back to Look Forward,” this essay argues that the organization has been the most impactful in three areas: producing, shaping, and driving key ideas, particularly on development and rights; generating such effective operational agencies as UNICEF and the World Food Program; and, especially in the immediate post–Cold War period, addressing major conflict risks through the Security Council. Since then, however, the UN has struggled to meet emerging challenges on many fronts and been increasingly hampered by internal ossification and institutional sprawl as well as internecine dysfunction. The twenty-first century has confronted the UN with further challenges relating most notably to climate change; to risks arising from new technologies; and to the increasingly fraught relationships between China, Russia, and the United States. If the past seventy-five years can offer one lesson, it is that new thinking and new ideas will need to drive the organization to evolve still further and faster, or else risk irrelevance.

The Study of Grain Boundaries in Ag-Sheathed Bscco Tapes by Scanning Transmission Electron Microscopy

1999 ◽  
Vol 5 (S2) ◽  
pp. 796-797
Author(s):  
K. Kishida ◽  
Y. Pan ◽  
N.D. Browning
Keyword(s):  
Grain Boundaries ◽  
Critical Current ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Point Of View ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Current Densities ◽  
Commercial Applications

Highly textured (Bi,Pb)2Sr2Ca2Cu3O10(Bi-2223)/Ag composite tapes have received considerable attention as high-Tc superconducting materials for electric power and high-magnetic-field applications because of their relatively high-critical current densities and their flexibility. In order to improve the performance of these tapes for many commercial applications, it is essential that the mechanisms that limit the critical current density are fully understood. Previous microscopical studies of these tapes have revealed that interfaces such as grain boundaries strongly influence the transport of large currents1. From a morphological point of view, several models have been proposed to describe potential current transport mechanisms. However, as these models consider mainly the large-scale configuration of the boundaries, the underlying mechanism controlling the properties is still unclear. In order to elucidate the exact role of grain boundaries, systematical studies on the effect of the atomic structure as well as any chemistry change that occurs at the interface are required.

scholarly journals Comparisons of Underlying Mechanisms, Clinical Efficacy and Safety Between Anti-PD-1 and Anti-PD-L1 Immunotherapy: The State-of-the-Art Review and Future Perspectives

2021 ◽  
Vol 12 ◽  
Author(s):  
Yating Zhao ◽  
Liu Liu ◽  
Liang Weng
Keyword(s):  
Clinical Efficacy ◽  
Clinical Performance ◽  
Underlying Mechanism ◽  
Efficacy And Safety ◽  
The Past ◽  
Real World Evidence ◽  
Wide Range ◽  
Novel Biomarkers ◽  
Cancer Types ◽  
Underlying Mechanisms

Over the past decade, diverse PD-1/PD-L1 blockades have demonstrated significant clinical benefit in across a wide range of tumor and cancer types. With the increasing number of PD-1/PD-L1 blockades available in the market, differences between the clinical performance of each of them started to be reported. Here, we provide a comprehensive historical and biological perspective regarding the underlying mechanism and clinical performance of PD-1/PD-L1 blockades, with an emphasis on the comparisons of their clinical efficacy and safety. The real-world evidence indicated that PD-1 blockade may be more effective than the PD-L1, though no significant differences were found as regards to their safety profiles. Future head-to-head studies are warranted for direct comparison between them. Finally, we summarize the yet to be elucidated questions and future promise of anti-PD-1/PD-L1 immunotherapy, including a need to explore novel biomarkers, novel combinatorial strategies, and their clinical use on chronic infection.

scholarly journals Spontaneous ring formation in wind-emitting accretion discs

2019 ◽  
Vol 625 ◽  
pp. A108 ◽  
Author(s):  
A. Riols ◽  
G. Lesur
Keyword(s):  
Growth Rates ◽  
Formation Process ◽  
Large Scale ◽  
Scale Height ◽  
Accretion Discs ◽  
Mhd Turbulence ◽  
The Past ◽  
Ring Form ◽  
Wide Range ◽  
The Ideal

Rings and gaps have been observed in a wide range of proto-planetary discs, from young systems like HLTau to older discs like TW Hydra. Recent disc simulations have shown that magnetohydrodynamic (MHD) turbulence (in both the ideal or non-ideal regime) can lead to the formation of rings and be an alternative to the embedded planets scenario. In this paper, we have investigated the way in which these ring form in this context and seek a generic formation process, taking into account the various dissipative regimes and magnetisations probed by the past simulations. We identify the existence of a linear and secular instability, driven by MHD winds, and giving birth to rings of gas that have a width larger than the disc scale height. We show that the linear theory is able to make reliable predictions regarding the growth rates, the contrast and spacing between ring and gap, by comparing these predictions to a series of 2D (axisymmetric) and 3D MHD numerical simulations. In addition, we demonstrate that these rings can act as dust traps provided that the disc is sufficiently magnetised, with plasma beta lower than 104. Given its robustness, the process identified in this paper could have important implications, not only for proto-planetary discs but also for a wide range of accreting systems threaded by large-scale magnetic fields.

The Romans in Britain

2017 ◽  
Author(s):  
Richard Hingley
Keyword(s):  
Material Culture ◽  
Indigenous People ◽  
Large Scale ◽  
First Century ◽  
Imperial Culture ◽  
The Past ◽  
Military Presence ◽  
Wide Range ◽  
Colonial Contact ◽  
And Control

This chapter addresses the ways in which Roman colonization operated within the Roman Empire’s province of Britannia during the first century CE, and analyzes theoretical aproaches to colonialism, colonisation, Romanisation, and imperalism. Roman colonies were formally established settlements of Roman citizens and several existed in Britain. But Britain was also colonized through additional mechanisms, including large-scale migration, a substantial military presence, and an incorporative imperial culture. Questions about the extent to which the indigenous people became Romanized or retained native ways are explored, and the chapter questions how thoroughly indigenous frontier populations adopted colonists’ ideologies and material culture. The evidence suggests a wide range of different responses to colonial contact and control, issues that have been drawn upon by the British in their colonial activities over the past centuries.

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